The influence of applied internal and external rotation on the pivot shift phenomenon.

PubMed

Kopf, Sebastian; Musahl, Volker; Perka, Carsten; Kauert, Ralf; Hoburg, Arnd; Becker, Roland

2017-04-01

The pivot shift test is performed in different techniques and the rotation of the tibia seems to have a significant impact on the amount of the pivot shift phenomenon. It has been hypothesised that external rotation will increase the phenomenon due to less tension at the iliotibial band in knee extension. Twenty-four patients with unilateral anterior cruciate ligament insufficiency were included prospectively. The pivot shift test was performed bilaterally in internal and external tibial rotation under general anaesthesia. Knee motion was captured using a femoral and a tibial inertial sensor. The difference between positive and negative peak values in Euclidean norm of acceleration was calculated to evaluate the amount of the pivot shift phenomenon. The pivot shift phenomenon was significantly increased in patients with ACL insufficiency when the test was performed in external [mean 5.2 ms - 2 (95% CI 4.3-6.0)] compared to internal tibial rotation [mean 4.4 ms - 2 (95% CI 3.5-5.4)] (p = 0.002). In healthy, contralateral knees did not show any difference between external [mean 4.0 ms - 2 (95% CI 3.3-4.7)] and internal tibial rotation [mean 4.0 ms - 2 (95% CI 3.4-4.6)] (ns). The pivot shift phenomenon was increased with external rotation in ACL-insufficient knees, and therefore, one should perform the pivot shift test, rather, in external rotation to easily evoke the, sometimes difficult to detect, pivot shift phenomenon. I (diagnostic study).

Effect of Tibial Plateau Levelling Osteotomy on Cranial Tibial Subluxation in the Feline Cranial Cruciate Deficient Stifle Joint: An Ex Vivo Experimental Study.

PubMed

Bilmont, A; Retournard, M; Asimus, E; Palierne, S; Autefage, A

2018-06-11

 This study evaluated the effects of tibial plateau levelling osteotomy on cranial tibial subluxation and tibial rotation angle in a model of feline cranial cruciate ligament deficient stifle joint.  Quadriceps and gastrocnemius muscles were simulated with cables, turnbuckles and a spring in an ex vivo limb model. Cranial tibial subluxation and tibial rotation angle were measured radiographically before and after cranial cruciate ligament section, and after tibial plateau levelling osteotomy, at postoperative tibial plateau angles of +5°, 0° and -5°.  Cranial tibial subluxation and tibial rotation angle were not significantly altered after tibial plateau levelling osteotomy with a tibial plateau angle of +5°. Additional rotation of the tibial plateau to a tibial plateau angle of 0° and -5° had no significant effect on cranial tibial subluxation and tibial rotation angle, although 2 out of 10 specimens were stabilized by a postoperative tibial plateau angle of -5°. No stabilization of the cranial cruciate ligament deficient stifle was observed in this model of the feline stifle, after tibial plateau levelling osteotomy.  Given that stabilization of the cranial cruciate ligament deficient stifle was not obtained in this model, simple transposition of the tibial plateau levelling osteotomy technique from the dog to the cat may not be appropriate. Schattauer GmbH Stuttgart.

The Effect of the Accelerometer Operating Range on Biomechanical Parameters: Stride Length, Velocity, and Peak Tibial Acceleration during Running

PubMed Central

Kiesewetter, Pierre; Milani, Thomas L.

2018-01-01

Previous studies have used accelerometers with various operating ranges (ORs) when measuring biomechanical parameters. However, it is still unclear whether ORs influence the accuracy of running parameters, and whether the different stiffnesses of footwear midsoles influence this accuracy. The purpose of the present study was to systematically investigate the influence of OR on the accuracy of stride length, running velocity, and on peak tibial acceleration. Twenty-one recreational heel strike runners ran on a 15-m indoor track at self-selected running speeds in three footwear conditions (low to high midsole stiffness). Runners were equipped with an inertial measurement unit (IMU) affixed to the heel cup of the right shoe and with a uniaxial accelerometer at the right tibia. Accelerometers (at the tibia and included in the IMU) with a high OR of ±70 g were used as the reference and the data were cut at ±32, ±16, and at ±8 g in post-processing, before calculating parameters. The results show that the OR influenced the outcomes of all investigated parameters, which were not influenced by tested footwear conditions. The lower ORs were associated with an underestimation error for all biomechanical parameters, which increased noticeably with a decreasing OR. It can be concluded that accelerometers with a minimum OR of ±32 g should be used to avoid inaccurate measurements. PMID:29303986

Effect of tibial plateau leveling on stability of the canine cranial cruciate-deficient stifle joint: an in vitro study.

PubMed

Reif, Ullrich; Hulse, Donald A; Hauptman, Joe G

2002-01-01

To evaluate the effect of tibial plateau leveling on joint motion in canine stifle joints in which the cranial cruciate ligament (CCL) had been severed. In vitro cadaver study. Six canine cadaver hind legs. Radiographs of the stifle joints were made to evaluate the tibial plateau angle with respect to the long axis of the tibia. The specimens were mounted in a custom-made testing device to measure cranio-caudal translation of the tibia with respect to the femur. An axial load was applied to the tibia, and its position was recorded in the normal stifle, after transection of the CCL, and after tibial plateau leveling. Further, the amount of caudal tibial thrust was measured in the tibial plateau leveled specimen while series of eight linearly increasing axial tibial loads were applied. Transection of the CCL resulted in cranial tibial translation when axial tibial load was applied. After tibial plateau leveling, axial loading resulted in caudal translation of the tibia. Increasing axial tibial load caused a linear increase in caudal tibial thrust in all tibial plateau-leveled specimens. After tibial plateau leveling, axial tibial load generates caudal tibial thrust, which increases if additional axial load is applied. Tibial plateau leveling osteotomy may prevent cranial translation during weight bearing in dogs with CCL rupture by converting axial load into caudal tibial thrust. The amount of caudal tibial thrust seems to be proportional to the amount of weight bearing. Copyright 2002 by The American College of Veterinary Surgeons

The effect of plate position and size on tibial slope in high tibial osteotomy: a cadaveric study.

PubMed

Rubino, L Joseph; Schoderbek, Robert J; Golish, S Raymond; Baumfeld, Joshua; Miller, Mark D

2008-01-01

Opening wedge high tibial osteotomies are performed for degenerative changes and varus. Opening wedge osteotomies can change proximal tibial slope in the sagittal plane, possibly imparting stability in the ACL-deficient knee. The aim of this study was to assess the effect of plate position and size on change in tibial slope. Eight cadaveric knees underwent opening wedge high tibial osteotomy with Puddu plates of each different size. Plates were placed anterior, central, and posterior for each size used. Lateral radiographs were obtained. Tibial slope was measured and compared with baseline slope. Tibial slope was affected by plate position (P < 0.05) and size (P < 0.001). Smaller, posterior plates had less effect on tibial slope. However, anterior and central plates increased tibial slope over all plate sizes (P < 0.05). This study found that tibial slope increases with opening wedge high tibial osteotomy. Larger corrections and anterior placement of the plate are associated with larger increases in slope.

Predictive formula for the length of tibial tunnel in anterior crucitate ligament reconstruction.

PubMed

Chernchujit, Bancha; Barthel, Thomas

2009-12-01

The anterior cruciate ligament (ACL) reconstruction using bone-patellar tendon bone graft is a common procedure in orthopedics. One challenging problem found is a graft-tunnel mismatch. Previous studies have reported the mathematic formula to predict the tibial angle length and angle to avoid graft-tunnel mismatch but these formulas have shown limited predictability. To propose a predictive formula for the length of tibial tunnel and to examine its predictability. Thirty six patients (26 males, 14 females) with ACL injury were included in this study. The preoperativemedial proximal tibial angle was measured. Intraoperatively, the tibial tunnel length and tibial entry point were measured. The postoperative coronal and saggital angle of tibial tunnel were measured from knee radiograph. The data were analysed by using trigonometry correlation and formulate the predictive formula of tibial tunnel length. We found that tibial tunnel length (T) has trigonometric correlation between the location of tibial tunnel entry point (w), coronal angle of tibial tunnel (b), saggital angle of tibial tunnel (a) and the medial proximal tibial slope (c) by using this formula T = Wcos(c)tan(b)/sin(a) This proposed predictive formula can well predict the length of the tibial tunnel at preoperative period to avoid graft-tunnel mismatch.

Al-Awadi/Raas-Rothschild/Schinzel (AARRS) phocomelia syndrome: case report and developmental field analysis.

PubMed

Subhani, Muhammad; Akangire, Gangaram; Kulkarni, Archana; Wilson, Golder N

2009-07-01

We describe a girl infant with anomalies of the left pelvis and lower limb (pelvic, femoral, and tibial hypogenesis with absent fibula), subtle facial changes, patent foraman ovale, single umbilical artery, single kidney, and imperforate anus. The external genitalia were asymmetric and ambiguous with normal uterus and ovaries visualized by ultrasound. The anomalies are compatible with previously reported cases of Al-Awadi/Raas-Rothschild/Schinzel (AARRS) phocomelia, an autosomal recessive disorder with WNT7 gene mutations documented in one family. We suggest that AARRS phocomelia, Fuhrmann syndrome, and similar conditions comprise a spectrum, and that the anomaly pattern derives from serial action of the same signal pathways within primary (e.g., the major axes), secondary (e.g., heart or limb primordia), and/or local (e.g., tibial-fibular differentiation) developmental fields.

Medial tibial plateau morphology and stress fracture location: A magnetic resonance imaging study.

PubMed

Yukata, Kiminori; Yamanaka, Issei; Ueda, Yuzuru; Nakai, Sho; Ogasa, Hiroyoshi; Oishi, Yosuke; Hamawaki, Jun-Ichi

2017-06-18

To determine the location of medial tibial plateau stress fractures and its relationship with tibial plateau morphology using magnetic resonance imaging (MRI). A retrospective review of patients with a diagnosis of stress fracture of the medial tibial plateau was performed for a 5-year period. Fourteen patients [three female and 11 male, with an average age of 36.4 years (range, 15-50 years)], who underwent knee MRI, were included. The appearance of the tibial plateau stress fracture and the geometry of the tibial plateau were reviewed and measured on MRI. Thirteen of 14 stress fractures were linear, and one of them stellated on MRI images. The location of fractures was classified into three types. Three fractures were located anteromedially (AM type), six posteromedially (PM type), and five posteriorly (P type) at the medial tibial plateau. In addition, tibial posterior slope at the medial tibial plateau tended to be larger when the fracture was located more posteriorly on MRI. We found that MRI showed three different localizations of medial tibial plateau stress fractures, which were associated with tibial posterior slope at the medial tibial plateau.

Comparison of volumetric bone mineral density in the tibial region of interest for ACL reconstruction.

PubMed

Klein, Scott A; Nyland, John; Caborn, David N M; Kocabey, Yavuz; Nawab, Akbar

2005-12-01

Adequate tibial bone mineral density (BMD) is essential to soft tissue graft fixation during anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to compare volumetric bone plug density measurements at the tibial region of interest for ACL reconstruction using a standardized immersion technique and Archimedes' principle. Cancellous bone cores were harvested from the proximal, middle, and distal metaphyseal regions of the lateral tibia and from the standard tibial tunnel location used for ACL reconstruction of 18 cadaveric specimens. Proximal tibial cores displayed 32.6% greater BMD than middle tibial cores and 31.8% greater BMD than distal tibial cores, but did not differ from the BMD of the tibial tunnel cores. Correlational analysis confirmed that the cancellous BMD in the tibial tunnel related to the cancellous BMD of the proximal and distal lateral tibial metaphysis. In conjunction with its adjacent cortical bone, the cancellous BMD of the region used for standard tibial tunnel placement provides an effective foundation for ACL graft fixation. In tibia with poor BMD, bicortical fixation that incorporates cortical bone from the distal tibial tunnel region is recommended.

Preserving the PCL during the tibial cut in total knee arthroplasty.

PubMed

Cinotti, G; Sessa, P; Amato, M; Ripani, F R; Giannicola, G

2017-08-01

Previous studies have shown that the PCL insertion may be damaged during the tibial cut performed in total knee arthroplasty. We investigated the maximum thickness of a tibial cut that preserves the PCL insertion and to what extent the posterior slope of the tibial cut and that of the patient's tibial plateaus affect the outcome. MR images of 83 knees were analysed. The maximum thickness of a tibial cut that preserves the PCL using a posterior slope of 0°, 3°, 5° and parallel to the patient's slope of the tibial plateau, was evaluated. Correlations between the results and the degrees of the posterior slope of the patient's tibial plateaus were also investigated. The maximum thickness of a tibial cut that preserves the entire PCL insertion was, on average, 5.5, 4.7, 4.2 and 3.1 mm when a posterior slope of 0°, 3°, 5° and parallel to the patients' tibial plateaus was used, respectively. When the 25th percentile was considered, the maximum thickness of a tibial cut that preserved the PCL was 4 and 3 mm with a tibial cut of 0° and 5° of posterior slope, respectively. The maximum thickness of a tibial cut that preserved the PCL was significantly greater in patients with a sagittal slope of the tibial plateaus more than 8° than in those with a sagittal slope less than 8°. In cruciate retaining implants, the PCL insertion may be spared in the majority of patients by performing a tibial cut of 4 mm, or even less when a posterior slope of 3°-5° is used. The clinical relevance of our study is that the execution of a conservative tibial cut, followed by a second tibial resection to achieve the thickness required for the tibial component to be implanted, may be an alternative technique to spare the PCL in CR TKA. II.

Analysis of the significance of the measurement of acceleration with respect to lateral laxity of the anterior cruciate ligament insufficient knee.

PubMed

Yoshimura, I; Naito, M; Hara, M; Zhang, J

2000-01-01

The purpose of this study was to assess dynamically the lateral thrust of anterior cruciate ligament (ACL) insufficient knees, and from the findings determine any relationship between ACL insufficiency and the later development of osteoarthritis (OA). We investigated 80 knees in 40 patients awaiting ACL reconstruction and 25 knees of 25 patients, which had undergone ACL reconstruction. An acceleration sensor was fixed to the anterior tibial tubercle and this 'acted' in two directions--medial lateral and perpendicular. The peak value of the lateral acceleration immediately after heel strike was significantly greater in the ACL insufficient knees when compared to their opposite normal knees. When the periods from injury were compared, the lateral thrust of the injured side after 3 years or more was significantly greater than in the first 3 years. There was no significant difference between the normal knees and the ACL reconstructed knees. The results indicated that the lateral acceleration peak value was significantly greater in the ACL insufficient knees than in their opposite normal knees.

Anthropometric measurements of tibial plateau and correlation with the current tibial implants.

PubMed

Erkocak, Omer Faruk; Kucukdurmaz, Fatih; Sayar, Safak; Erdil, Mehmet Emin; Ceylan, Hasan Huseyin; Tuncay, Ibrahim

2016-09-01

The aim of the study was to make an anthropometric analysis at the resected surfaces of the proximal tibia in the Turkish population and to compare the data with the dimensions of tibial components in current use. We hypothesized that tibial components currently available on the market do not fulfil the requirements of this population and a new tibial component design may be required, especially for female patients with small stature. Anthropometric data from the proximal tibia of 226 knees in 226 Turkish subjects were measured using magnetic resonance imaging. We measured the mediolateral, middle anteroposterior, medial and lateral anteroposterior dimensions and the aspect ratio of the resected proximal tibial surface. All morphological data were compared with the dimensions of five contemporary tibial implants, including asymmetric and symmetric design types. The dimensions of the tibial plateau of Turkish knees demonstrated significant differences according to gender (P < 0.05). Among the different tibial implants reviewed, neither asymmetric nor symmetric designs exhibited a perfect conformity to proximal tibial morphology in size and shape. The vast majority of tibial implants involved in this study tend to overhang anteroposteriorly, and a statistically significant number of women (21 %, P < 0.05) had tibial anteroposterior diameters smaller than the smallest available tibial component. Tibial components designed according to anthropometric measurements of Western populations do not perfectly meet the requirements of Turkish population. These data could provide the basis for designing the optimal and smaller tibial component for this population, especially for women, is required for best fit. II.

Medial tibial plateau morphology and stress fracture location: A magnetic resonance imaging study

PubMed Central

Yukata, Kiminori; Yamanaka, Issei; Ueda, Yuzuru; Nakai, Sho; Ogasa, Hiroyoshi; Oishi, Yosuke; Hamawaki, Jun-ichi

2017-01-01

AIM To determine the location of medial tibial plateau stress fractures and its relationship with tibial plateau morphology using magnetic resonance imaging (MRI). METHODS A retrospective review of patients with a diagnosis of stress fracture of the medial tibial plateau was performed for a 5-year period. Fourteen patients [three female and 11 male, with an average age of 36.4 years (range, 15-50 years)], who underwent knee MRI, were included. The appearance of the tibial plateau stress fracture and the geometry of the tibial plateau were reviewed and measured on MRI. RESULTS Thirteen of 14 stress fractures were linear, and one of them stellated on MRI images. The location of fractures was classified into three types. Three fractures were located anteromedially (AM type), six posteromedially (PM type), and five posteriorly (P type) at the medial tibial plateau. In addition, tibial posterior slope at the medial tibial plateau tended to be larger when the fracture was located more posteriorly on MRI. CONCLUSION We found that MRI showed three different localizations of medial tibial plateau stress fractures, which were associated with tibial posterior slope at the medial tibial plateau. PMID:28660141

Kinematically aligned total knee arthroplasty limits high tibial forces, differences in tibial forces between compartments, and abnormal tibial contact kinematics during passive flexion.

PubMed

Roth, Joshua D; Howell, Stephen M; Hull, Maury L

2018-06-01

Following total knee arthroplasty (TKA), high tibial forces, large differences in tibial forces between the medial and lateral compartments, and anterior translation of the contact locations of the femoral component on the tibial component during passive flexion indicate abnormal knee function. Because the goal of kinematically aligned TKA is to restore native knee function without soft tissue release, the objectives were to determine how well kinematically aligned TKA limits high tibial forces, differences in tibial forces between compartments, and anterior translation of the contact locations of the femoral component on the tibial component during passive flexion. Using cruciate retaining components, kinematically aligned TKA was performed on thirteen human cadaveric knee specimens with use of manual instruments without soft tissue release. The tibial forces and tibial contact locations were measured in both the medial and lateral compartments from 0° to 120° of passive flexion using a custom tibial force sensor. The average total tibial force (i.e. sum of medial + lateral) ranged from 5 to 116 N. The only significant average differences in tibial force between compartments occurred at 0° of flexion (29 N, p = 0.0008). The contact locations in both compartments translated posteriorly in all thirteen kinematically aligned TKAs by an average of 14 mm (p < 0.0001) and 18 mm (p < 0.0001) in the medial and lateral compartments, respectively, from 0° to 120° of flexion. After kinematically aligned TKA, average total tibial forces due to the soft tissue restraints were limited to 116 N, average differences in tibial forces between compartments were limited to 29 N, and a net posterior translation of the tibial contact locations was observed in all kinematically aligned TKAs during passive flexion from 0° to 120°, which are similar to what has been measured previously in native knees. While confirmation in vivo is warranted, these findings give surgeons who perform kinematically aligned TKA confidence that the alignment method and surgical technique limit high tibial forces, differences in tibial forces between compartments, and anterior translation of the tibial contact locations during passive flexion.

Maximizing tibial coverage is detrimental to proper rotational alignment.

PubMed

Martin, Stacey; Saurez, Alex; Ismaily, Sabir; Ashfaq, Kashif; Noble, Philip; Incavo, Stephen J

2014-01-01

Traditionally, the placement of the tibial component in total knee arthroplasty (TKA) has focused on maximizing coverage of the tibial surface. However, the degree to which maximal coverage affects correct rotational placement of symmetric and asymmetric tibial components has not been well defined and might represent an implant design issue worthy of further inquiry. Using four commercially available tibial components (two symmetric, two asymmetric), we sought to determine (1) the overall amount of malrotation that would occur if components were placed for maximal tibial coverage; and (2) whether the asymmetric designs would result in less malrotation than the symmetric designs when placed for maximal coverage in a computer model using CT reconstructions. CT reconstructions of 30 tibial specimens were used to generate three-dimensional tibia reconstructions with attention to the tibial anatomic axis, the tibial tubercle, and the resected tibial surface. Using strict criteria, four commercially available tibial designs (two symmetric, two asymmetric) were placed on the resected tibial surface. The resulting component rotation was examined. Among all four designs, 70% of all tibial components placed in orientation maximizing fit to resection surface were internally malrotated (average 9°). The asymmetric designs had fewer cases of malrotation (28% and 52% for the two asymmetric designs, 100% and 96% for the two symmetric designs; p < 0.001) and less malrotation on average (2° and 5° for the asymmetric designs, 14° for both symmetric designs; p < 0.001). Maximizing tibial coverage resulted in implant malrotation in a large percentage of cases. Given similar amounts of tibial coverage, correct rotational positioning was more likely to occur with the asymmetric designs. Malrotation of components is an important cause of failure in TKA. Priority should be given to correct tibial rotational positioning. This study suggested that it is easier to balance rotation and coverage with asymmetric tibial baseplates; clinical research will need to determine whether the observed difference affects patellar tracking, loosening rates, or the likelihood of revisions after TKA.

Tibial tunnel aperture location during single-bundle posterior cruciate ligament reconstruction: comparison of tibial guide positions.

PubMed

Shin, Young-Soo; Han, Seung-Beom; Hwang, Yeok-Ku; Suh, Dong-Won; Lee, Dae-Hee

2015-05-01

We aimed to compare posterior cruciate ligament (PCL) tibial tunnel location after tibial guide insertion medial (between the PCL remnant and the medial femoral condyle) and lateral (between the PCL remnant and the anterior cruciate ligament) to the PCL stump as determined by in vivo 3-dimensional computed tomography (3D-CT). Tibial tunnel aperture location was analyzed by immediate postoperative in vivo CT in 66 patients who underwent single-bundle PCL reconstruction, 31 by over-the-PCL and 35 by under-the-PCL tibial guide insertion techniques. Tibial tunnel positions were measured in the medial to lateral and proximal to distal directions of the posterior proximal tibia. The center of the tibial tunnel aperture was located more laterally (by 2.7 mm) in the over-the-PCL group than in the under-the-PCL group (P = .040) and by a relative percentage (absolute value/tibial width) of 3.2% (P = .031). Tibial tunnel positions in the proximal to distal direction, determined by absolute value and relative percentage, were similar in the 2 groups. Tibial tunnel apertures were located more laterally after lateral-to-the-PCL tibial guide insertion than after medial-to-the-PCL tibial guide insertion. There was, however, no significant difference between these techniques in distance from the joint line to the tibial tunnel aperture. Insertion lateral to the PCL stump may result in better placement of the PCL in its anatomic footprint. Level III, retrospective comparative study. Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

The Effect of Tibial Plateau Levelling Osteotomy on Stifle Extensor Mechanism Load: A Canine Ex Vivo Study.

PubMed

Drew, Jarrod O; Glyde, Mark R; Hosgood, Giselle L; Hayes, Alex J

2018-02-01

 To evaluate the effect of tibial plateau levelling osteotomy on stifle extensor mechanism load in an ex vivo cruciate-intact canine cadaveric model.   Ex vivo mechanical testing study.  Cadaveric canine pelvic limbs ( n  = 6).  A 21-mm tibial radial osteotomy was performed on pelvic limbs ( n  = 6) prior to being mounted into a load-bearing limb press. The proximal tibial segment was incrementally rotated until the anatomical tibial plateau angle had been rotated to at least 1°. The proportional change in stifle extensor mechanism load between the anatomical tibial plateau angle and the neutralized (∼6.5 degrees) and over-rotated (∼1°) tibial plateau angle was analysed using a one-sample t -test against a null hypothesis of no change. A p -value ≤0.05 was considered significant.  There was no significant change in the stifle extensor mechanism load from the anatomical tibial plateau angle (308 N [261-355 N]) to the neutralized tibial plateau angle (313 N [254-372 N]; p =.81), or from the anatomical tibial plateau angle to the over-rotated tibial plateau angle (303 N [254-352 N; p  = 0.67).  Tibial plateau levelling osteotomy does not significantly alter stifle extensor mechanism load at either a neutralized or over-rotated tibial plateau angle in our cruciate-intact model. Schattauer GmbH Stuttgart.

Models of tibial fracture healing in normal and Nf1-deficient mice.

PubMed

Schindeler, Aaron; Morse, Alyson; Harry, Lorraine; Godfrey, Craig; Mikulec, Kathy; McDonald, Michelle; Gasser, Jürg A; Little, David G

2008-08-01

Delayed union and nonunion are common complications associated with tibial fractures, particularly in the distal tibia. Existing mouse tibial fracture models are typically closed and middiaphyseal, and thus poorly recapitulate the prevailing conditions following surgery on a human open distal tibial fracture. This report describes our development of two open tibial fracture models in the mouse, where the bone is broken either in the tibial midshaft (mid-diaphysis) or in the distal tibia. Fractures in the distal tibial model showed delayed repair compared to fractures in the tibial midshaft. These tibial fracture models were applied to both wild-type and Nf1-deficient (Nf1+/-) mice. Bone repair has been reported to be exceptionally problematic in human NF1 patients, and these patients can also spontaneously develop tibial nonunions (known as congenital pseudarthrosis of the tibia), which are recalcitrant to even vigorous intervention. pQCT analysis confirmed no fundamental differences in cortical or cancellous bone in Nf1-deficient mouse tibiae compared to wild-type mice. Although no difference in bone healing was seen in the tibial midshaft fracture model, the healing of distal tibial fractures was found to be impaired in Nf1+/- mice. The histological features associated with nonunited Nf1+/- fractures were variable, but included delayed cartilage removal, disproportionate fibrous invasion, insufficient new bone anabolism, and excessive catabolism. These findings imply that the pathology of tibial pseudarthrosis in human NF1 is complex and likely to be multifactorial.

Local delivery of HMGB1 in gelatin sponge scaffolds combined with mesenchymal stem cell sheets to accelerate fracture healing.

PubMed

Xue, Deting; Zhang, Wei; Chen, Erman; Gao, Xiang; Liu, Ling; Ye, Chenyi; Tan, Yanbin; Pan, Zhijun; Li, Hang

2017-06-27

Fracture nonunion and delayed union continue to pose challenges for orthopedic surgeons. In the present study, we combined HMGB1 gelatin sponges with MSC sheets to promote bone healing after surgical treatment of rat tibial fractures. The HMGB1 gelatin sponge scaffolds supported the expansion of mesenchymal stem cells (MSCs) and promoted the osteogenic differentiation of MSCs and MSC sheets. Lentiviral vectors were then used to overexpress HMGB1 in MSCs. The results indicated that HMGB1 promotes the osteogenic differentiation of MSCs through the STAT3 pathway. Both siRNA and a STAT3 inhibitor downregulated STAT3, further confirming that HMGB1 induces the osteogenic differentiation of MSCs partly via the STAT3 signal pathway. In a rat tibial osteotomy model, we demonstrated the ability of HMGB1 gelatin sponge scaffolds to increase bone formation. The addition of MSC sheets further enhanced fracture healing. These findings support the use of HMGB1-loaded gelatin sponge scaffolds combined with MSC sheets to enhance fracture healing after surgical intervention.

Local delivery of HMGB1 in gelatin sponge scaffolds combined with mesenchymal stem cell sheets to accelerate fracture healing

PubMed Central

Xue, Deting; Zhang, Wei; Chen, Erman; Gao, Xiang; Liu, Ling; Ye, Chenyi; Tan, Yanbin; Pan, Zhijun; Li, Hang

2017-01-01

Fracture nonunion and delayed union continue to pose challenges for orthopedic surgeons. In the present study, we combined HMGB1 gelatin sponges with MSC sheets to promote bone healing after surgical treatment of rat tibial fractures. The HMGB1 gelatin sponge scaffolds supported the expansion of mesenchymal stem cells (MSCs) and promoted the osteogenic differentiation of MSCs and MSC sheets. Lentiviral vectors were then used to overexpress HMGB1 in MSCs. The results indicated that HMGB1 promotes the osteogenic differentiation of MSCs through the STAT3 pathway. Both siRNA and a STAT3 inhibitor downregulated STAT3, further confirming that HMGB1 induces the osteogenic differentiation of MSCs partly via the STAT3 signal pathway. In a rat tibial osteotomy model, we demonstrated the ability of HMGB1 gelatin sponge scaffolds to increase bone formation. The addition of MSC sheets further enhanced fracture healing. These findings support the use of HMGB1-loaded gelatin sponge scaffolds combined with MSC sheets to enhance fracture healing after surgical intervention. PMID:28431400

Tarsal tunnel syndrome

MedlinePlus

Tibial nerve dysfunction; Neuropathy - posterior tibial nerve; Peripheral neuropathy - tibial nerve; Tibial nerve entrapment ... Tarsal tunnel syndrome is an unusual form of peripheral neuropathy . It occurs when there is damage to the ...

Tibial plateau fracture following gracilis-semitendinosus anterior cruciate ligament reconstruction: The tibial tunnel stress-riser.

PubMed

Sundaram, R O; Cohen, D; Barton-Hanson, N

2006-06-01

Tibial plateau fractures following anterior cruciate ligament (ACL) reconstruction are extremely rare. This is the first reported case of a tibial plateau fracture following four-strand gracilis-semitendinosus autograft ACL reconstruction. The tibial tunnel alone may behave as a stress riser which can significantly reduce bone strength.

Posterior tibial slope as a risk factor for anterior cruciate ligament rupture in soccer players.

PubMed

Senişik, Seçkin; Ozgürbüz, Cengizhan; Ergün, Metin; Yüksel, Oğuz; Taskiran, Emin; Işlegen, Cetin; Ertat, Ahmet

2011-01-01

Anterior cruciate ligament (ACL) is the primary stabilizer of the knee. An impairment of any of the dynamic or static stability providing factors can lead to overload on the other factors and ultimately to deterioration of knee stability. This can result in anterior tibial translation and rupture of the ACL. The purpose of this study was to examine the influence of tibial slope on ACL injury risk on soccer players. A total of 64 elite soccer players and 45 sedentary controls were included in this longitudinal and controlled study. The angle between the tibial mid-diaphysis line and the line between the anterior and posterior edges of the medial tibial plateau was measured as the tibial slope via lateral radiographs. Individual player exposure, and injuries sustained by the participants were prospectively recorded. Eleven ACL injuries were documented during the study period. Tibial slope was not different between soccer players and sedentary controls. Tibial slope in the dominant and non-dominant legs was greater for the injured players compared to the uninjured players. The difference reached a significant level only for the dominant legs (p < 0.001). While the tibial slopes of the dominant and non-dominant legs were not different on uninjured players (p > 0.05), a higher tibial slope was observed in dominant legs of injured players (p < 0.05). Higher tibial slope on injured soccer players compared to the uninjured ones supports the idea that the tibial slope degree might be an important risk factor for ACL injury. Key pointsDominant legs' tibial slopes of the injured players were significantly higher compared to the uninjured players (p < 0.001).Higher tibial slope was determined in dominant legs compared to the non-dominant side, for the injured players (p = 0.042). Different tibial slope measures in dominant and non-dominant legs might be the result of different loading and/or adaptation patterns in soccer.

Trifurcation of the tibial nerve within the tarsal tunnel.

PubMed

Develi, Sedat

2018-05-01

The tibial nerve is the larger terminal branch of the sciatic nerve and it terminates in the tarsal tunnel by giving lateral and medial plantar nerves. We present a rare case of trifurcation of the tibial nerve within the tarsal tunnel. The variant nerve curves laterally after branching from the tibial nerve and courses deep to quadratus plantae muscle. Interestingly, posterior tibial artery was also terminating by giving three branches. These branches were accompanying the terminal branches of the tibial nerve.

Comparison of the primary stability of different tibial baseplate concepts to retain both cruciate ligaments during total knee arthroplasty.

PubMed

Nowakowski, Andrej M; Stangel, Melanie; Grupp, Thomas M; Valderrabano, Victor

2013-10-01

A novel tibial baseplate design (Transversal Support Tibial Plateau) as a new treatment concept for bi-cruciate retaining total knee arthroplasty is evaluated for mechanical stability and compared to other tibial baseplate designs. This concept should provide better primary stability and thus, less subsidence, than implantation of two separate unicondylar tibial baseplates. Different baseplates were implanted into synthetic bone specimens (Sawbones® Pacific Research Laboratories, Inc., Washington, USA), all uncemented. Using a standardized experimental setup, subsidence was achieved, enabling comparison of the models regarding primary stability. Overall implant subsidence was significantly increased for the two separate unicondylar tibial baseplates versus the new Transversal Support Tibial Plateau concept, which showed comparable levels to a conventional tibial baseplate. Reduced subsidence results in better primary stability. Linking of two separate baseplates appears to provide increased primary stability in terms of bony fixation, comparable to that of a conventional single tibial baseplate. © 2013. Published by Elsevier Ltd. All rights reserved.

Effect of Tibial Posterior Slope on Knee Kinematics, Quadriceps Force, and Patellofemoral Contact Force After Posterior-Stabilized Total Knee Arthroplasty.

PubMed

Okamoto, Shigetoshi; Mizu-uchi, Hideki; Okazaki, Ken; Hamai, Satoshi; Nakahara, Hiroyuki; Iwamoto, Yukihide

2015-08-01

We used a musculoskeletal model validated with in vivo data to evaluate the effect of tibial posterior slope on knee kinematics, quadriceps force, and patellofemoral contact force after posterior-stabilized total knee arthroplasty. The maximum quadriceps force and patellofemoral contact force decreased with increasing posterior slope. Anterior sliding of the tibial component and anterior impingement of the anterior aspect of the tibial post were observed with tibial posterior slopes of at least 5° and 10°, respectively. Increased tibial posterior slope contributes to improved exercise efficiency during knee extension, however excessive tibial posterior slope should be avoided to prevent knee instability. Based on our computer simulation we recommend tibial posterior slopes of less than 5° in posterior-stabilized total knee arthroplasty. Copyright © 2015 Elsevier Inc. All rights reserved.

Current Trends in Anterior Cruciate Ligament Reconstruction: A Review

PubMed Central

Vaishya, Raju; Ingole, Sachin; Vijay, Vipul

2015-01-01

Anterior cruciate ligament reconstruction (ACLR) is an accepted and established surgical technique for anterior cruciate ligament (ACL) injuries and is now being practiced across the globe in increasing numbers. Although most patients get good to excellent results in the short-term after ACLR, its consequences in the long-term in prevention or acceleration of knee osteoarthritis (OA) are not yet well-defined. Still, there are many debatable issues related to ACLR, such as the appropriate timing of surgery, graft selection, fixation methods of the graft, operative techniques, rehabilitation after surgery, and healing augmentation techniques. Most surgeons prefer not to wait long after an ACL injury to do an ACLR, as delayed reconstruction is associated with secondary damages to the intra- and periarticular structures of the knee. Autografts are the preferred choice of graft in primary ACLR, and hamstring tendons are the most popular amongst surgeons. Single bundle ACLR is being practiced by the majority, but double bundle ACLR is getting popular due to its theoretical advantage of providing more anatomical reconstruction. A preferred construct is the interference fixation (Bio-screw) at the tibial site and the suspensory method of fixation at the femoral site. In a single bundle hamstring graft, a transportal approach for creating a femoral tunnel has recently become more popular than the trans-tibial technique. Various healing augmentation techniques, including the platelet rich plasma (PRP), have been tried after ACLR, but there is still no conclusive proof of their efficacy. Accelerated rehabilitation is seemingly more accepted immediately after ACLR. PMID:26697280

Tibial lengthening over humeral and tibial intramedullary nails in patients with sequelae of poliomyelitis: a comparative study.

PubMed

Chen, Daoyun; Chen, Jianmin; Jiang, Yao; Liu, Fanggang

2011-06-01

Leg discrepancy is common after poliomyelitis. Tibial lengthening is an effective way to solve this problem. It is believed lengthening over a tibial intramedullary nail can provide a more comfortable lengthening process than by the conventional technique. However, patients with sequelae of poliomyelitis typically have narrow intramedullary canals allowing limited space for inserting a tibial intramedullary nail and Kirschner wires. To overcome this problem, we tried using humeral nails instead of tibial nails in the lengthening procedure. In this study, we used humeral nails in 20 tibial lengthening procedures and compared the results with another group of patients who were treated with tibial lengthening over tibial intramedullary nails. The mean consolidation index, percentage of increase and external fixation index did not show significant differences between the two groups. However, less blood loss and shorter operating time were noted in the humeral nail group. More patients encountered difficulty with the inserted intramedullary nail in the tibial nail group procedure. The complications did not show a statistically significant difference between the two techniques on follow-up. In conclusion, we found the humeral nail lengthening technique was more suitable in leg discrepancy patients with sequelae of poliomyelitis.

The Valgus Inclination of the Tibial Component Increases the Risk of Medial Tibial Condylar Fractures in Unicompartmental Knee Arthroplasty.

PubMed

Inoue, Shinji; Akagi, Masao; Asada, Shigeki; Mori, Shigeshi; Zaima, Hironori; Hashida, Masahiko

2016-09-01

Medial tibial condylar fractures (MTCFs) are a rare but serious complication after unicompartmental knee arthroplasty. Although some surgical pitfalls have been reported for MTCFs, it is not clear whether the varus/valgus tibial inclination contributes to the risk of MTCFs. We constructed a 3-dimensional finite elemental method model of the tibia with a medial component and assessed stress concentrations by changing the inclination from 6° varus to 6° valgus. Subsequently, we repeated the same procedure adding extended sagittal bone cuts of 2° and 10° in the posterior tibial cortex. Furthermore, we calculated the bone volume that supported the tibial component, which is considered to affect stress distribution in the medial tibial condyle. Stress concentrations were observed on the medial tibial metaphyseal cortices and on the anterior and posterior tibial cortices in the corner of cut surfaces in all models; moreover, the maximum principal stresses on the posterior cortex were larger than those on the anterior cortex. The extended sagittal bone cuts in the posterior tibial cortex increased the stresses further at these 3 sites. In the models with a 10° extended sagittal bone cut, the maximum principal stress on the posterior cortex increased as the tibial inclination changed from 6° varus to 6° valgus. The bone volume decreased as the inclination changed from varus to valgus. In this finite element method, the risk of MTCFs increases with increasing valgus inclination of the tibial component and with increased extension of the sagittal cut in the posterior tibial cortex. Copyright © 2016 Elsevier Inc. All rights reserved.

Cranial tibial wedge osteotomy: a technique for eliminating cranial tibial thrust in cranial cruciate ligament repair.

PubMed

Slocum, B; Devine, T

1984-03-01

Cranial tibial wedge osteotomy, surgical technique for cranial cruciate ligament rupture, was performed on 19 stifles in dogs. This procedure leveled the tibial plateau, thus causing weight-bearing forces to be compressive and eliminating cranial tibial thrust. Without cranial tibial thrust, which was antagonistic to the cranial cruciate ligament and its surgical reconstruction, cruciate ligament repairs were allowed to heal without constant loads. This technique was meant to be used as an adjunct to other cranial cruciate ligament repair techniques.

The Tibial Slope in Patients With Achondroplasia: Its Characterization and Possible Role in Genu Recurvatum Development.

PubMed

Brooks, Jaysson T; Bernholt, David L; Tran, Kevin V; Ain, Michael C

2016-06-01

Genu recurvatum, a posterior resting position of the knee, is a common lower extremity deformity in patients with achondroplasia and has been thought to be secondary to ligamentous laxity. To the best of our knowledge, the role of the tibial slope has not been investigated, and no studies describe the tibial slope in patients with achondroplasia. Our goals were to characterize the tibial slope in children and adults with achondroplasia, explore its possible role in the development of genu recurvatum, and compare the tibial slope in patients with achondroplasia to that in the general population. We reviewed 252 lateral knee radiographs of 130 patients with achondroplasia seen at our clinic from November 2007 through September 2013. Patients were excluded if they had previous lower extremity surgery or radiographs with extreme rotation. We analyzed patient demographics and, on all radiographs, the tibial slope. We then compared the mean tibial slope to norms in the literature. Tibial slopes >90 degrees had an anterior tibial slope and received a positive prefix. Statistical analysis included intraclass and interclass reliability, Pearson correlation coefficient, and the Student t tests (significance, P<0.05). The overall mean tibial slope for the 252 knees was +1.32±7 degrees, which was significantly more anterior than the normal slopes reported in the literature for adults (7.2 to 10.7 degrees, P=0.0001) and children (10 to 11 degrees, P=0.0001). The Pearson correlation coefficient for mean tibial slope and age showed negative correlations of -0.4011 and -0.4335 for left and right knees, respectively. This anterior tibial slope produces proximal and posterior vector force components, which may shift the knee posteriorly in weightbearing. The mean tibial slope is significantly more anterior in patients with achondroplasia than in the general population; however, this difference diminishes as patients' age. An anterior tibial slope may predispose to a more posterior resting knee position, also known as genu recurvatum. Level IV-retrospective case series.

Decision-Making Influences Tibial Impact Accelerations During Lateral Cutting.

PubMed

Lucas, Logan A; England, Benjamin S; Mason, Travis W; Lanning, Christopher R; Miller, Taylor M; Morgan, Alexander M; Almonroeder, Thomas G

2018-05-29

Lower extremity musculoskeletal injuries are common in sports such as basketball and soccer. Athletes competing in sports of this nature must maneuver in response to the actions of their teammates, opponents, etc. This limits their ability to pre-plan movements. The purpose of this study was to compare impact accelerations during pre-planned vs. un-planned lateral cutting. Thirty subjects (15 males, 15 females) performed pre-planned and un-planned cuts while we analyzed impact accelerations using an accelerometer secured to their tibia. For the pre-planned condition, subjects were aware of the movement to perform before initiating a trial. For the un-planned condition, subjects initiated their movement and then reacted to the illumination of one of three visual stimuli which dictated whether they would cut, land, or land-and-jump. A mixed-model ANOVA with a between factor of sex (male, female) and a within factor of condition (pre-planned, un-planned) was used to analyze the magnitude and variability of the impact accelerations for the cutting trials. Both males and females demonstrated higher impact accelerations (p = .010) and a trend toward greater inter-trial variability (p = .073) for the un-planned cutting trials (vs. pre-planned cuts). Un-planned cutting may place greater demands on the musculoskeletal system.

What Components Comprise the Measurement of the Tibial Tuberosity-Trochlear Groove Distance in a Patellar Dislocation Population?

PubMed

Tensho, Keiji; Akaoka, Yusuke; Shimodaira, Hiroki; Takanashi, Seiji; Ikegami, Shota; Kato, Hiroyuki; Saito, Naoto

2015-09-02

The tibial tuberosity-trochlear groove distance is used as an indicator for medial tibial tubercle transfer; however, to our knowledge, no studies have verified whether this distance is strongly affected by tubercle lateralization at the proximal part of the tibia. We hypothesized that the tibial tuberosity-trochlear groove distance is mainly affected by tibial tubercle lateralization at the proximal part of the tibia. Forty-four patients with a history of patellar dislocation and forty-four age and sex-matched controls were analyzed with use of computed tomography. The tibial tuberosity-trochlear groove distance, tibial tubercle lateralization, trochlear groove medialization, and knee rotation were measured and were compared between the patellar dislocation group and the control group. The association between the tibial tuberosity-trochlear groove distance and three other parameters was calculated with use of the Pearson correlation coefficient and partial correlation analysis. There were significant differences in the tibial tuberosity-trochlear groove distance (p < 0.001) and knee rotation (p < 0.001), but there was no difference in the tibial tubercle lateralization (p = 0.13) and trochlear groove medialization (p = 0.08) between the patellar dislocation group and the control group. The tibial tuberosity-trochlear groove distance had no linear correlation with tubercle lateralization (r = 0.21) or groove medialization (r = -0.15); however, knee rotation had a good positive correlation in the patellar dislocation group (r = 0.62). After adjusting for the remaining parameters, knee rotation strongly correlated with the tibial tuberosity-trochlear groove distance (r = 0.69, p < 0.001), whereas tubercle lateralization showed moderate significant correlations in the patellar dislocation group (r = 0.42; p = 0.005). Because the tibial tuberosity-trochlear groove distance is affected more by knee rotation than by tubercle malposition, its use as an indicator for tibial tubercle transfer may not be appropriate. Surgical decisions of tibial tubercle transfer should be made after the careful analysis of several underlying factors of patellar dislocation. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

Tibial component alignment and risk of loosening in unicompartmental knee arthroplasty: a radiographic and radiostereometric study.

PubMed

Barbadoro, P; Ensini, A; Leardini, A; d'Amato, M; Feliciangeli, A; Timoncini, A; Amadei, F; Belvedere, C; Giannini, S

2014-12-01

Unicompartmental knee arthroplasty (UKA) has shown a higher rate of revision compared with total knee arthroplasty. The success of UKA depends on prosthesis component alignment, fixation and soft tissue integrity. The tibial cut is the crucial surgical step. The hypothesis of the present study is that tibial component malalignment is correlated with its risk of loosening in UKA. This study was performed in twenty-three patients undergoing primary cemented unicompartmental knee arthroplasties. Translations and rotations of the tibial component and the maximum total point motion (MTPM) were measured using radiostereometric analysis at 3, 6, 12 and 24 months. Standard radiological evaluations were also performed immediately before and after surgery. Varus/valgus and posterior slope of the tibial component and tibial-femoral axes were correlated with radiostereometric micro-motion. A survival analysis was also performed at an average of 5.9 years by contacting patients by phone. Varus alignment of the tibial component was significantly correlated with MTPM, anterior tibial sinking, varus rotation and anterior and medial translations from radiostereometry. The posterior slope of the tibial component was correlated with external rotation. The survival rate at an average of 5.9 years was 89%. The two patients who underwent revision presented a tibial component varus angle of 10° for both. There is correlation between varus orientation of the tibial component and MTPM from radiostereometry in unicompartmental knee arthroplasties. Particularly, a misalignment in varus larger than 5° could lead to risk of loosening the tibial component. Prognostic studies-retrospective study, Level II.

Proximal Tibial Bone Graft

MedlinePlus

... All Site Content AOFAS / FootCareMD / Treatments Proximal Tibial Bone Graft Page Content What is a bone graft? Bone grafts may be needed for various ... the proximal tibia. What is a proximal tibial bone graft? Proximal tibial bone graft (PTBG) is a ...

Importance of tibial slope for stability of the posterior cruciate ligament deficient knee.

PubMed

Giffin, J Robert; Stabile, Kathryne J; Zantop, Thore; Vogrin, Tracy M; Woo, Savio L-Y; Harner, Christopher D

2007-09-01

Previous studies have shown that increasing tibial slope can shift the resting position of the tibia anteriorly. As a result, sagittal osteotomies that alter slope have recently been proposed for treatment of posterior cruciate ligament (PCL) injuries. Increasing tibial slope with an osteotomy shifts the resting position anteriorly in a PCL-deficient knee, thereby partially reducing the posterior tibial "sag" associated with PCL injury. This shift in resting position from the increased slope causes a decrease in posterior tibial translation compared with the PCL-deficient knee in response to posterior tibial and axial compressive loads. Controlled laboratory study. Three knee conditions were tested with a robotic universal force-moment sensor testing system: intact, PCL-deficient, and PCL-deficient with increased tibial slope. Tibial slope was increased via a 5-mm anterior opening wedge osteotomy. Three external loading conditions were applied to each knee condition at 0 degrees, 30 degrees, 60 degrees, 90 degrees, and 120 degrees of knee flexion: (1) 134-N anterior-posterior (A-P) tibial load, (2) 200-N axial compressive load, and (3) combined 134-N A-P and 200-N axial loads. For each loading condition, kinematics of the intact knee were recorded for the remaining 5 degrees of freedom (ie, A-P, medial-lateral, and proximal-distal translations, internal-external and varus-valgus rotations). Posterior cruciate ligament deficiency resulted in a posterior shift of the tibial resting position to 8.4 +/- 2.6 mm at 90 degrees compared with the intact knee. After osteotomy, tibial slope increased from 9.2 degrees +/- 1.0 degrees in the intact knee to 13.8 degrees +/- 0.9 degrees. This increase in slope reduced the posterior sag of the PCL-deficient knee, shifting the resting position anteriorly to 4.0 +/- 2.0 mm at 90 degrees. Under a 200-N axial compressive load with the osteotomy, an additional increase in anterior tibial translation to 2.7 +/- 1.7 mm at 30 degrees was observed. Under a 134-N A-P load, the osteotomy did not significantly affect total A-P translation when compared with the PCL-deficient knee. However, because of the anterior shift in resting position, there was a relative decrease in posterior tibial translation and increase in anterior tibial translation. Increasing tibial slope in a PCL-deficient knee reduces tibial sag by shifting the resting position of the tibia anteriorly. This sag is even further reduced when the knee is subjected to axial compressive loads. These data suggest that increasing tibial slope may be beneficial for patients with PCL-deficient knees.

Total knee arthroplasty after high tibial osteotomy. A comparison study in patients who had bilateral total knee replacement.

PubMed

Meding, J B; Keating, E M; Ritter, M A; Faris, P M

2000-09-01

The outcome of total knee replacement after high tibial osteotomy remains uncertain. We hypothesized that the results of total knee replacement with or without a previous high tibial osteotomy are similar. The results of a consecutive series of thirty-nine bilateral total knee arthroplasties performed with cement at an average of 8.7 years after unilateral high tibial osteotomy were reviewed. There were twenty-seven men and twelve women. Preoperatively, the knee scores according to the system of the Knee Society were similar for all of the knees; however, valgus alignment and patella infera were more common in the knees with a previous high tibial osteotomy. Bilateral total knee replacement was staged in seven patients and was simultaneous in thirty-two patients. The results of the total knee arthroplasties were retrospectively reviewed with respect to the knee and function scores according to the system of the Knee Society, the radiographic findings, and the complications. Intraoperatively, no notable differences were identified in the number of medial, lateral, or lateral patellar releases required. However, less lateral tibial bone was resected in the group with a previous high tibial osteotomy (average, 3.3 millimeters) than in the group without a high tibial osteotomy (average, 7.5 millimeters). The average duration of follow-up was 7.5 years (range, three to sixteen years) in the group with a previous high tibial osteotomy and 6.8 years (range, two to ten years) in the group without a high tibial osteotomy. At the time of the final follow-up, the knee and function scores were similar for the two groups (89.0 and 81.0 points, respectively, for the group with a previous high tibial osteotomy, and 89.6 and 83.9 points, respectively, for the group without a high tibial osteotomy). Although more knees were free of pain in the group without a previous high tibial osteotomy (thirty-six) than in the group with a previous osteotomy (thirty-three), this difference was not found to be significant with the numbers available (p = 0.4810). Knee alignment and stability, femoral and tibial component alignment, and range of motion also were similar in both groups postoperatively. One allpolyethylene tibial component was revised in the high tibial osteotomy group. Two knees in each group required manipulation. There were no deep infections. While patients with a previous high tibial osteotomy may have important differences preoperatively, including valgus alignment, patella infera, and decreased bone stock in the proximal part of the tibia, the present study suggests that the clinical and radiographic results of primary total knee arthroplasty in knees with and without a previous high tibial osteotomy are not substantially different. In our relatively small group of patients, the previous high tibial osteotomy had no adverse effect on the outcome of the subsequent total knee replacement.

Tibial Tray Thickness Significantly Increases Medial Tibial Bone Resorption in Cobalt-Chromium Total Knee Arthroplasty Implants.

PubMed

Martin, J Ryan; Watts, Chad D; Levy, Daniel L; Miner, Todd M; Springer, Bryan D; Kim, Raymond H

2017-01-01

Stress shielding is an uncommon complication associated with primary total knee arthroplasty. Patients are frequently identified radiographically with minimal clinical symptoms. Very few studies have evaluated risk factors for postoperative medial tibial bone loss. We hypothesized that thicker cobalt-chromium tibial trays are associated with increased bone loss. We performed a retrospective review of 100 posterior stabilized, fixed-bearing total knee arthroplasty where 50 patients had a 4-mm-thick tibial tray (thick tray cohort) and 50 patients had a 2.7-mm-thick tibial tray (thin tray cohort). A clinical evaluation and a radiographic assessment of medial tibial bone loss were performed on both cohorts at a minimum of 2 years postoperatively. Mean medial tibial bone loss was significantly higher in the thick tray cohort (1.07 vs 0.16 mm; P = .0001). In addition, there were significantly more patients with medial tibial bone loss in the thick tray group compared with the thin tray group (44% vs 10%, P = .0002). Despite these differences, there were no statistically significant differences in range of motion, knee society score, complications, or revision surgeries performed. A thicker cobalt-chromium tray was associated with significantly more medial tibial bone loss. Despite these radiographic findings, we found no discernable differences in clinical outcomes in our patient cohort. Further study and longer follow-up are needed to understand the effects and clinical significance of medial tibial bone loss. Copyright © 2016 Elsevier Inc. All rights reserved.

Anatomic tibial component design can increase tibial coverage and rotational alignment accuracy: a comparison of six contemporary designs.

PubMed

Dai, Yifei; Scuderi, Giles R; Bischoff, Jeffrey E; Bertin, Kim; Tarabichi, Samih; Rajgopal, Ashok

2014-12-01

The aim of this study was to comprehensively evaluate contemporary tibial component designs against global tibial anatomy. We hypothesized that anatomically designed tibial components offer increased morphological fit to the resected proximal tibia with increased alignment accuracy compared to symmetric and asymmetric designs. Using a multi-ethnic bone dataset, six contemporary tibial component designs were investigated, including anatomic, asymmetric, and symmetric design types. Investigations included (1) measurement of component conformity to the resected tibia using a comprehensive set of size and shape metrics; (2) assessment of component coverage on the resected tibia while ensuring clinically acceptable levels of rotation and overhang; and (3) evaluation of the incidence and severity of component downsizing due to adherence to rotational alignment and overhang requirements, and the associated compromise in tibial coverage. Differences in coverage were statistically compared across designs and ethnicities, as well as between placements with or without enforcement of proper rotational alignment. Compared to non-anatomic designs investigated, the anatomic design exhibited better conformity to resected tibial morphology in size and shape, higher tibial coverage (92% compared to 85-87%), more cortical support (posteromedial region), lower incidence of downsizing (3% compared to 39-60%), and less compromise of tibial coverage (0.5% compared to 4-6%) when enforcing proper rotational alignment. The anatomic design demonstrated meaningful increase in tibial coverage with accurate rotational alignment compared to symmetric and asymmetric designs, suggesting its potential for less intra-operative compromises and improved performance. III.

The risk of sacrificing the PCL in cruciate retaining total knee arthroplasty and the relationship to the sagittal inclination of the tibial plateau.

PubMed

Sessa, Pasquale; Fioravanti, Giulio; Giannicola, Giuseppe; Cinotti, Gianluca

2015-01-01

In cruciate retaining total knee arthroplasty (TKA), a partial avulsion of PCL may occur when en-bloc tibial osteotomy is performed. We evaluated the effects of a tibial cut performed with different degrees of posterior slope on PCL insertion and whether the results are affected by the sagittal inclination of the patient's tibial plateau. We selected 83 MRIs of knees showing mild or no degenerative changes. The effects of a simulated tibial cut performed with a posterior slope of 0°, 3°, 5° and parallel to the patient's tibial plateau inclination on PCL insertion in the proximal tibia were investigated. The results were correlated with the degree of posterior inclination of the tibial plateau. Every angle we used for the tibial cut caused a PCL avulsion greater than 50%. The percentage of PCL avulsion significantly increased with increasing the posterior slope of the tibial cut. Patients with sagittal tibial plateau inclination <5° showed greater PCL avulsion than those with sagittal inclination >8°. Most of the PCL insertion is likely to be sacrificed when resection of the proximal tibia is performed en-block. The risk of PCL avulsion is reduced in patients showing a marked posterior inclination of the tibial plateau, but even in this group of patients a surgical technique aimed at sparing most of the PCL insertion is necessary. Copyright © 2014 Elsevier B.V. All rights reserved.

Histological analysis of the tibial anterior cruciate ligament insertion.

PubMed

Oka, Shinya; Schuhmacher, Peter; Brehmer, Axel; Traut, Ulrike; Kirsch, Joachim; Siebold, Rainer

2016-03-01

This study was performed to investigate the morphology of the tibial anterior cruciate ligament (ACL) by histological assessment. The native (undissected) tibial ACL insertion of six fresh-frozen cadaveric knees was cut into four sagittal sections parallel to the long axis of the medial tibial spine. For histological evaluation, the slices were stained with haematoxylin and eosin, Safranin O and Russell-Movat pentachrome. All slices were digitalized and analysed at a magnification of 20×. The anterior tibial ACL insertion was bordered by a bony anterior ridge. The most medial ACL fibres inserted from the medial tibial spine and were adjacent to the articular cartilage of the medial tibial plateau. Parts of the bony insertions of the anterior and posterior horns of the lateral meniscus were in close contact with the lateral part of the tibial ACL insertion. A small fat pad was located just posterior to the functional ACL fibres. The anterior-posterior length of the medial ACL insertion was an average of 10.8 ± 1.1 mm compared with the lateral, which was only 6.2 ± 1.1 mm (p < 0.001). There were no central or posterolateral inserting ACL fibres. The shape of the bony tibial ACL insertion was 'duck-foot-like'. In contrast to previous findings, the functional mid-substance fibres arose from the most posterior part of the 'duck-foot' in a flat and 'c-shaped' way. The most anterior part of the tibial ACL insertion was bordered by a bony anterior ridge and the most medial by the medial tibial spine. No posterolateral fibres nor ACL bundles have been found histologically. This histological investigation may improve our understanding of the tibial ACL insertion and may provide important information for anatomical ACL reconstruction.

Section modulus is the optimum geometric predictor for stress fractures and medial tibial stress syndrome in both male and female athletes.

PubMed

Franklyn, Melanie; Oakes, Barry; Field, Bruce; Wells, Peter; Morgan, David

2008-06-01

Various tibial dimensions and geometric parameters have been linked to stress fractures in athletes and military recruits, but many mechanical parameters have still not been investigated. Sedentary people, athletes with medial tibial stress syndrome, and athletes with stress fractures have smaller tibial geometric dimensions and parameters than do uninjured athletes. Cohort study; Level of evidence, 3. Using a total of 88 subjects, male and female patients with either a tibial stress fracture or medial tibial stress syndrome were compared with both uninjured aerobically active controls and uninjured sedentary controls. Tibial scout radiographs and cross-sectional computed tomography images of all subjects were scanned at the junction of the midthird and distal third of the tibia. Tibial dimensions were measured directly from the films; other parameters were calculated numerically. Uninjured exercising men have a greater tibial cortical cross-sectional area than do their sedentary and injured counterparts, resulting in a greater value of some other cross-sectional geometric parameters, particularly the section modulus. However, for women, the cross-sectional areas are either not different or only marginally different, and there are few tibial dimensions or geometric parameters that distinguish the uninjured exercisers from the sedentary and injured subjects. In women, the main difference between the groups was the distribution of cortical bone about the centroid as a result of the different values of section modulus. Last, medial tibial stress syndrome subjects had smaller tibial cross-sectional dimensions than did their uninjured exercising counterparts, suggesting that medial tibial stress syndrome is not just a soft-tissue injury but also a bony injury. The results show that in men, the cross-sectional area and the section modulus are the key parameters in the tibia to distinguish exercise and injury status, whereas for women, it is the section modulus only.

Reliability of tunnel angle in ACL reconstruction: two-dimensional versus three-dimensional guide technique.

PubMed

Leiter, Jeff R S; de Korompay, Nevin; Macdonald, Lindsey; McRae, Sheila; Froese, Warren; Macdonald, Peter B

2011-08-01

To compare the reliability of tibial tunnel position and angle produced with a standard ACL guide (two-dimensional guide) or Howell 65° Guide (three-dimensional guide) in the coronal and sagittal planes. In the sagittal plane, the dependent variables were the angle of the tibial tunnel relative to the tibial plateau and the position of the tibial tunnel with respect to the most posterior aspect of the tibia. In the coronal plane, the dependent variables were the angle of the tunnel with respect to the medial joint line of the tibia and the medial and lateral placement of the tibial tunnel relative to the most medial aspect of the tibia. The position and angle of the tibial tunnel in the coronal and sagittal planes were determined from anteroposterior and lateral radiographs, respectively, taken 2-6 months postoperatively. The two-dimensional and three-dimensional guide groups included 28 and 24 sets of radiographs, respectively. Tibial tunnel position was identified, and tunnel angle measurements were completed. Multiple investigators measured the position and angle of the tunnel 3 times, at least 7 days apart. The angle of the tibial tunnel in the coronal plane using a two-dimensional guide (61.3 ± 4.8°) was more horizontal (P < 0.05) than tunnels drilled with a three-dimensional guide (64.7 ± 6.2°). The position of the tibial tunnel in the sagittal plane was more anterior (P < 0.05) in the two-dimensional (41.6 ± 2.5%) guide group compared to the three-dimensional guide group (43.3 ± 2.9%). The Howell Tibial Guide allows for reliable placement of the tibial tunnel in the coronal plane at an angle of 65°. Tibial tunnels were within the anatomical footprint of the ACL with either technique. Future studies should investigate the effects of tibial tunnel angle on knee function and patient quality of life. Case-control retrospective comparative study, Level III.

What are the bias, imprecision, and limits of agreement for finding the flexion-extension plane of the knee with five tibial reference lines?

PubMed

Brar, Abheetinder S; Howell, Stephen M; Hull, Maury L

2016-06-01

Internal-external (I-E) malrotation of the tibial component is associated with poor function after total knee arthroplasty (TKA). Kinematically aligned (KA) TKA uses a functionally defined flexion-extension (F-E) tibial reference line, which is parallel to the F-E plane of the extended knee, to set I-E rotation of the tibial component. Sixty-two, three-dimensional bone models of normal knees were analyzed. We computed the bias (mean), imprecision (±standard deviation), and limits of agreement (mean±2 standard deviations) of the angle between five anatomically defined tibial reference lines used in mechanically aligned (MA) TKA and the F-E tibial reference line (+external). The following are the bias, imprecision, and limits of agreement of the angle between the F-E tibial reference line and 1) the tibial reference lines connecting the medial border (-2°±6°, -14° to 10°), medial 1/3 (6°±6°, -6° to 18°), and the most anterior point of the tibial tubercle (9°±4°, -1° to 17°) with the center of the posterior cruciate ligament, and 2) the tibial reference lines perpendicular to the posterior condylar axis of the tibia (-3°±4°, -11° to 5°), and a line connecting the centers of the tibial condyles (1°±4°, -7° to 9°). Based on these in vitro findings, it might be prudent to reconsider setting the I-E rotation of the tibial component to tibial reference lines that have bias, imprecision, and limits of agreement that fall outside the -7° to 10° range associated with high function after KA TKA. Copyright © 2016 Elsevier B.V. All rights reserved.

The transverse ligament as a landmark for tibial sagittal insertions of the anterior cruciate ligament: a cadaveric study.

PubMed

Kongcharoensombat, Wirat; Ochi, Mitsuo; Abouheif, Mohamed; Adachi, Nobuo; Ohkawa, Shingo; Kamei, Goki; Okuhara, Atushi; Shibuya, Hoyatoshi; Niimoto, Takuya; Nakasa, Tomoyuki; Nakamae, Atsuo; Deie, Masataka

2011-10-01

The purpose of this study was to determine the relation between the position of the transverse ligament, the anterior edge of the anterior cruciate ligament (ACL) tibial footprint, and the center of the ACL tibial insertion. We used arthroscopy for localization of the anatomic landmarks, followed by insertions of guide pins under direct visualization, and then the position of these guide pins was checked on plain lateral radiographs. The transverse ligament and the anterior aspect of the ACL tibial footprint were identified by arthroscopy in 20 unpaired cadaveric knees (10 left and 10 right). Guide pins were inserted with tibial ACL adapter drill guides under direct observation at the transverse ligament, the anterior aspect of the tibial footprint, and the center of tibial insertion of the ACL. Then, plain lateral radiographs of specimens were taken. The Amis and Jakob line was used to define the attachment of the ACL tibial insertion and the transverse ligament. A sagittal percentage of the location of the insertion point was determined and calculated from the anterior margin of the tibia in the anteroposterior direction. The transverse ligament averaged 21.20% ± 4.1%, the anterior edge of the ACL tibial insertion averaged 21.60% ± 4.0%, and the center of the ACL tibial insertion averaged 40.30% ± 4.8%. There were similar percent variations between the transverse ligament and the anterior edge of the ACL tibial insertion, with no significant difference between them (P = .38). Intraobserver and interobserver reliability was high, with small standard errors of measurement. This study shows that the transverse ligament coincides with the anterior edge of the ACL tibial footprint in the sagittal plane. The transverse ligament can be considered as a new landmark for tibial tunnel positioning during anatomic ACL reconstruction. Copyright © 2011 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

A 3D finite element model to investigate prosthetic interface stresses of different posterior tibial slope.

PubMed

Shen, Yi; Li, Xiaomiao; Fu, Xiaodong; Wang, Weili

2015-11-01

Posterior tibial slope that is created during proximal tibial resection in total knee arthroplasty has emerged as an important factor in the mechanics of the knee joint and the surgical outcome. But the ideal degree of posterior tibial slope for recovery of the knee joint function and preventions of complications remains controversial and should vary in different racial groups. The objective of this paper is to investigate the effects of posterior tibial slope on contact stresses in the tibial polyethylene component of total knee prostheses. Three-dimensional finite element analysis was used to calculate contact stresses in tibial polyethylene component of total knee prostheses subjected to a compressive load. The 3D finite element model of total knee prosthesis was constructed from the images produced by 3D scanning technology. Stresses in tibial polyethylene component were calculated with four different posterior tibial slopes (0°, 3°, 6° and 9°). The 3D finite element model of total knee prosthesis we presented was well validated. We found that the stress distribution in the polythene as evaluated by the distributions of the von Mises stress, the maximum principle stress, the minimum principle stress and the Cpress were more uniform with 3° and 6° posterior tibial slopes than with 0° and 9° posterior tibial slopes. Moreover, the peaks of the above stresses and trends of changes with increasing degree of knee flexion were more ideal with 3° and 6° posterior slopes. The results suggested that the tibial component inclination might be favourable to 7°-10° so far as the stress distribution is concerned. The range of the tibial component inclination also can decrease the wear of polyethylene. Chinese posterior tibial slope is bigger than in the West, and the current domestic use of prostheses is imported from the West, so their demands to tilt back bone cutting can lead to shorten the service life of prostheses; this experiment result is of important clinical significance, guiding orthopaedic surgeon after the best angle to cut bone.

ACL double-bundle reconstruction with one tibial tunnel provides equal stability compared to two tibial tunnels.

PubMed

Drews, Björn Holger; Seitz, Andreas Martin; Huth, Jochen; Bauer, Gerhard; Ignatius, Anita; Dürselen, Lutz

2017-05-01

The purpose of this study was to investigate whether an anterior cruciate ligament (ACL) double-bundle reconstruction with one tibial tunnel displays the same in vitro stability as a conventional double-bundle reconstruction with two tibial tunnels when using the same tensioning protocol. In 11 fresh-frozen cadaveric knees, ACL double-bundle reconstruction with one and two tibial tunnels was performed. The two grafts were tightened using 80 N in different flexion angles (anteromedial-bundle at 60° and posterolateral-bundle at 15°). Anterior tibial translation (134 N) and translation with combined rotatory and valgus loads (10 Nm valgus stress and 4 Nm internal tibial torque) were determined at 0°, 30°, 60° and 90° flexion. Measurements were taken in intact ACL, resected ACL, three-tunnel reconstruction and four-tunnel reconstruction. Additionally, the tension on the grafts was determined. Student's t test was performed for statistical analysis of the related samples. Significance was set at p < 0.017 according to Bonferroni correction. The two reconstructive techniques displayed no significant differences in comparison with the intact ACL in anterior tibial translation at 0°, 60° and 90° of flexion. The same results were obtained for the anterior tibial translation with a combined rotatory load at 60° and 90°. When directly comparing both reconstructive techniques, there were no significant differences for the anterior tibial translation and combined rotatory load at all flexion angles. The measured tension on grafts displayed similar load sharing between both bundles. Except at full extension, both grafts displayed a significantly different tension increase under anterior tibial translation for both techniques (p = 0.0086). Tightening both bundles in ACL double-bundle reconstruction with one or two tibial tunnels in different flexion angles achieved comparable restoration of stability, although there was different load sharing on the bundles. With regard to individualized ACL reconstruction, the double-bundle technique with one tibial tunnel offers a possibility to address small tibial insertion sites without compromising the advantages of a double-bundle procedure.

Lateral thrust of anterior cruciate ligament-insufficient knees and posterior cruciate ligament-insufficient knees.

PubMed

Yoshimura, Ichiro; Naito, Masatoshi; Zhang, Jingfan

2002-01-01

Leaving anterior cruciate ligament (ACL) insufficiency and posterior cruciate ligament (PCL) insufficiency untreated frequently leads to osteoarthritis (OA). The purpose of this study was to evaluate dynamically the lateral thrust of ACL-insufficient knees and PCL-insufficient knees, and from the findings investigate the relationship between cruciate ligament insufficiency and OA occurrence. An acceleration sensor was attached to the affected and control anterior tibial tubercles, acting in medial-lateral and perpendicular directions. The lateral thrust immediately after heel strike was measured continuously by a telemeter under stabilised walking conditions. When compared to the contralateral healthy knee, the peak value of lateral acceleration immediately after heel strike was significantly larger in the ACL-insufficient knee; and lateral thrust was increased, but not significantly, in the PCL-insufficient knee. Given that lateral thrust of the knee during walking increases due to ACL or PCL injury, it may be a principal contributor to OA progression.

Foot strike pattern differently affects the axial and transverse components of shock acceleration and attenuation in downhill trail running.

PubMed

Giandolini, Marlene; Horvais, Nicolas; Rossi, Jérémy; Millet, Guillaume Y; Samozino, Pierre; Morin, Jean-Benoît

2016-06-14

Trail runners are exposed to a high number of shocks, including high-intensity shocks on downhill sections leading to greater risk of osseous overuse injury. The type of foot strike pattern (FSP) is known to influence impact severity and lower-limb kinematics. Our purpose was to investigate the influence of FSP on axial and transverse components of shock acceleration and attenuation during an intense downhill trail run (DTR). Twenty-three trail runners performed a 6.5-km DTR (1264m of negative elevation change) as fast as possible. Four tri-axial accelerometers were attached to the heel, metatarsals, tibia and sacrum. Accelerations were continuously recorded at 1344Hz and analyzed over six sections (~400 steps per subject). Heel and metatarsal accelerations were used to identify the FSP. Axial, transverse and resultant peak accelerations, median frequencies and shock attenuation within the impact-related frequency range (12-20Hz) were assessed between tibia and sacrum. Multiple linear regressions showed that anterior (i.e. forefoot) FSPs were associated with higher peak axial acceleration and median frequency at the tibia, lower transverse median frequencies at the tibia and sacrum, and lower transverse peak acceleration at the sacrum. For resultant acceleration, higher tibial median frequency but lower sacral peak acceleration were reported with forefoot striking. FSP therefore differently affects the components of impact shock acceleration. Although a forefoot strike reduces impact severity and impact frequency content along the transverse axis, a rearfoot strike decreases them in the axial direction. Globally, the attenuation of axial and resultant impact-related vibrations was improved using anterior FSPs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tibial Stress Injuries: Decisive Diagnosis and Treatment of "Shin Splints."

ERIC Educational Resources Information Center

Couture, Christopher J.; Karlson, Kristine A.

2002-01-01

Tibial stress injuries, commonly called shin splints, often result when bone remodeling processes adopt inadequately to repetitive stress. Physicians who are caring for athletic patients must have a thorough understanding of this continuum of injuries, including medial tibial stress syndrome and tibial stress fractures, because there are…

"Clothesline technique" for proximal tibial shaft fracture fixation using conventional intramedullary nail: a simple, useful, and inexpensive technique to prevent fracture malalignment.

PubMed

Belangero, William Dias; Santos Pires, Robinson Esteves; Livani, Bruno; Rossi, Felipe Lins; de Andrade, Andre Luis Lugnani

2018-05-01

Treatment of proximal tibial shaft fractures is always challenging. Despite the development of modern techniques, the literature still shows high complication rates, especially regarding proximal fragment malalignment. It is well known that knee position in flexion during tibial nailing is responsible for extension and valgus deformities of the proximal fragment. Unlike in tibial shaft fractures, nails do not reduce proximal tibial fractures due to the medullary canal width. This study aims to describe a simple, useful, and inexpensive technique to prevent valgus and extension deformities when treating proximal tibial fractures using conventional nails: the so-called clothesline technique.

Temporary Fixation Using a Long Femoral-tibial Nail to Treat a Displaced Medial Tibial Plateau Fracture in a 90-year-old Patient: A Case Report

PubMed Central

Batta, V; Sinha, S; Trompeter, A

2017-01-01

Introduction: Tibial plateau fractures are complex injuries in the elderly population. When traditional methods of fixation are not suitable, an alternative method needs to be chosen for a favorable outcome. We demonstrate a previously undescribed treatment for displaced tibial plateau fractures in the very elderly with poor soft-tissue integrity. Case Report: A 90-year-old woman suffered an open, Gustilo Grade IIIA, displaced fracture of the tibial plateau. An intramedullary knee arthrodesis, the femoral-tibial nail was used to temporarily stabilize her fracture. She was able to weight bear immediately postfixation. Conclusion: A long femoral-tibial nail allows favorable fracture and soft tissue healing, ease of nursing and immediate full weight-bearing. It shows good promise and should be considered as a management option when traditional methods are not applicable in select patients. PMID:29181350

Temporary Fixation Using a Long Femoral-tibial Nail to Treat a Displaced Medial Tibial Plateau Fracture in a 90-year-old Patient: A Case Report.

PubMed

Batta, V; Sinha, S; Trompeter, A

2017-01-01

Tibial plateau fractures are complex injuries in the elderly population. When traditional methods of fixation are not suitable, an alternative method needs to be chosen for a favorable outcome. We demonstrate a previously undescribed treatment for displaced tibial plateau fractures in the very elderly with poor soft-tissue integrity. A 90-year-old woman suffered an open, Gustilo Grade IIIA, displaced fracture of the tibial plateau. An intramedullary knee arthrodesis, the femoral-tibial nail was used to temporarily stabilize her fracture. She was able to weight bear immediately postfixation. A long femoral-tibial nail allows favorable fracture and soft tissue healing, ease of nursing and immediate full weight-bearing. It shows good promise and should be considered as a management option when traditional methods are not applicable in select patients.

Higher Rate of Revision in PFC Sigma Primary Total Knee Arthroplasty With Mismatch of Femoro-Tibial Component Sizes.

PubMed

Young, Simon W; Clarke, Henry D; Graves, Stephen E; Liu, Yen-Liang; de Steiger, Richard N

2015-05-01

Total knee arthroplasty (TKA) systems permit a degree of femoro-tibial component size mismatch. The effect of mismatched components on revision rates has not been evaluated in a large study. We reviewed 21,906 fixed-bearing PFC Sigma primary TKAs using the Australian Orthopaedic Association National Joint Replacement Registry, dividing patients into three groups: no femoro-tibial size mismatch, tibial component size > femoral component size, and femoral component > tibial component. Revision rates were higher when the femoral size was greater than the tibia, compared to both equal size (HR = 1.20 (1.00, 1.45), P = 0.047) and to tibial size greater than femoral (HR = 1.60 (1.08, 2.37), P = 0.019). Potential mechanisms to explain these findings include edge loading of polyethylene and increased tibial component stresses. Copyright © 2014 Elsevier Inc. All rights reserved.

Fracture reduction and primary ankle arthrodesis: a reliable approach for severely comminuted tibial pilon fracture.

PubMed

Beaman, Douglas N; Gellman, Richard

2014-12-01

Posttraumatic arthritis and prolonged recovery are typical after a severely comminuted tibial pilon fracture, and ankle arthrodesis is a common salvage procedure. However, few reports discuss the option of immediate arthrodesis, which may be a potentially viable approach to accelerate overall recovery in patients with severe fracture patterns. (1) How long does it take the fracture to heal and the arthrodesis to fuse when primary ankle arthrodesis is a component of initial fracture management? (2) How do these patients fare clinically in terms of modified American Orthopaedic Foot and Ankle Society (AOFAS) scores and activity levels after this treatment? (3) Does primary ankle arthrodesis heal in an acceptable position when anterior ankle arthrodesis plates are used? During a 2-year period, we performed open fracture reduction and internal fixation in 63 patients. Eleven patients (12 ankles) with severely comminuted high-energy tibial pilon fractures were retrospectively reviewed after surgical treatment with primary ankle arthrodesis and fracture reduction. Average patient age was 58 years, and minimum followup was 6 months (average, 14 months; range, 6-22 months). Anatomically designed anterior ankle arthrodesis plates were used in 10 ankles. Ring external fixation was used in nine ankles with concomitant tibia fracture or in instances requiring additional fixation. Clinical evaluation included chart review, interview, the AOFAS ankle-hindfoot score, and radiographic evaluation. All of the ankle arthrodeses healed at an average of 4.4 months (range, 3-5 months). One patient had a nonunion at the metaphyseal fracture, which healed with revision surgery. The average AOFAS ankle-hindfoot score was 83 with 88% having an excellent or good result. Radiographic and clinical analysis confirmed a plantigrade foot without malalignment. No patients required revision surgery for malunion. Primary ankle arthrodesis combined with fracture reduction for the severely comminuted tibial pilon fracture reliably healed and restored acceptable function in this highly selective patient group. Ring external fixation may be a useful adjunct to internal fixation, and this concept should be further studied. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing... Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be implanted...

Tibial stress injuries: decisive diagnosis and treatment of 'shin splints'.

PubMed

Couture, Christopher J; Karlson, Kristine A

2002-06-01

Tibial stress injuries, commonly called 'shin splints,' often result when bone remodeling processes adapt inadequately to repetitive stress. Physicians who care for athletic patients need a thorough understanding of this continuum of injuries, including medial tibial stress syndrome and tibial stress fractures, because there are implications for appropriate diagnosis, management, and prevention.

Anterior tibial stress fractures treated with anterior tension band plating in high-performance athletes.

PubMed

Cruz, Alexandre Santa; de Hollanda, João Paris Buarque; Duarte, Aires; Hungria Neto, José Soares

2013-06-01

The non-surgical treatment of anterior tibial cortex stress fractures requires long periods of abstention from sports activities and often results in non-union. Many different surgical techniques have already been previously described to treat these fractures, but there is no consensus on the best treatment. We describe the outcome of treatment using anterior tibial tension band plating in three high-performance athletes (4 legs) with anterior tibial cortex stress fractures. Tibial osteosynthesis with a 3.5-mm locking compression plate in the anterolateral aspect of the tibia was performed in all patients diagnosed with anterior tibial stress fracture after September 2010 at Santa Casa Hospital. All of the fractures were consolidated within a period of 3 months after surgery, allowing for an early return to pre-injury levels of competitive sports activity. There were no infection, non-union, malunion or anterior knee pain complications. Anterior tibial tension band plating leads to prompt fracture consolidation and is a good alternative for the treatment of anterior tibial cortex stress fractures. Bone grafts were shown to be unnecessary.

High tibial osteotomy in knee laxities: Concepts review and results

PubMed Central

Robin, Jonathan G.; Neyret, Philippe

2016-01-01

Patients with unstable, malaligned knees often present a challenging management scenario, and careful attention must be paid to the clinical history and examination to determine the priorities of treatment. Isolated knee instability treated with ligament reconstruction and isolated knee malalignment treated with periarticular osteotomy have both been well studied in the past. More recently, the effects of high tibial osteotomy on knee instability have been studied. Lateral closing-wedge high tibial osteotomy tends to reduce the posterior tibial slope, which has a stabilising effect on anterior tibial instability that occurs with ACL deficiency. Medial opening-wedge high tibial osteotomy tends to increase the posterior tibia slope, which has a stabilising effect in posterior tibial instability that occurs with PCL deficiency. Overall results from recent studies indicate that there is a role for combined ligament reconstruction and periarticular knee osteotomy. The use of high tibial osteotomy has been able to extend the indication for ligament reconstruction which, when combined, may ultimately halt the evolution of arthritis and preserve their natural knee joint for a longer period of time. Cite this article: Robin JG, Neyret P. High tibial osteotomy in knee laxities: Concepts review and results. EFORT Open Rev 2016;1:3-11. doi: 10.1302/2058-5241.1.000001. PMID:28461908

Medial Tibial Stress Shielding: A Limitation of Cobalt Chromium Tibial Baseplates.

PubMed

Martin, J Ryan; Watts, Chad D; Levy, Daniel L; Kim, Raymond H

2017-02-01

Stress shielding is a well-recognized complication associated with total knee arthroplasty. However, this phenomenon has not been thoroughly described. Specifically, no study to our knowledge has evaluated the radiographic impact of utilizing various tibial component compositions on tibial stress shielding. We retrospectively reviewed 3 cohorts of 50 patients that had a preoperative varus deformity and were implanted with a titanium, cobalt chromium (CoCr), or an all polyethylene tibial implant. A radiographic comparative analysis was performed to evaluate the amount of medial tibial bone loss in each cohort. In addition, a clinical outcomes analysis was performed on the 3 cohorts. The CoCr was noted to have a statistically significant increase in medial tibial bone loss compared with the other 2 cohorts. The all polyethylene cohort had a statistically significantly higher final Knee Society Score and was associated with the least amount of stress shielding. The CoCr tray is the most rigid of 3 implants that were compared in this study. Interestingly, this cohort had the highest amount of medial tibial bone loss. In addition, 1 patient in the CoCr cohort had medial soft tissue irritation which was attributed to a prominent medial tibial tray which required revision surgery to mitigate the symptoms. Copyright © 2016 Elsevier Inc. All rights reserved.

Tibial bone fractures occurring after medioproximal tibial bone grafts for oral and maxillofacial reconstruction.

PubMed

Kim, Il-Kyu; Cho, Hyun-Young; Pae, Sang-Pill; Jung, Bum-Sang; Cho, Hyun-Woo; Seo, Ji-Hoon

2013-12-01

Oral and maxillofacial defects often require bone grafts to restore missing tissues. Well-recognized donor sites include the anterior and posterior iliac crest, rib, and intercalvarial diploic bone. The proximal tibia has also been explored as an alternative donor site. The use of the tibia for bone graft has many benefits, such as procedural ease, adequate volume of cancellous and cortical bone, and minimal complications. Although patients rarely complain of pain, swelling, discomfort, or dysfunction, such as gait disturbance, both patients and surgeons should pay close attention to such after effects due to the possibility of tibial fracture. The purpose of this study is to analyze tibial fractures that occurring after osteotomy for a medioproximal tibial graft. An analysis was intended for patients who underwent medioproximal tibial graft between March 2004 and December 2011 in Inha University Hospital. A total of 105 subjects, 30 females and 75 males, ranged in age from 17 to 78 years. We investigated the age, weight, circumstance, and graft timing in relation to tibial fracture. Tibial fractures occurred in four of 105 patients. There were no significant differences in graft region, shape, or scale between the fractured and non-fractured patients. Patients who undergo tibial grafts must be careful of excessive external force after the operation.

Influence of post-cam design of posterior stabilized knee prosthesis on tibiofemoral motion during high knee flexion.

PubMed

Lin, Kun-Jhih; Huang, Chang-Hung; Liu, Yu-Liang; Chen, Wen-Chuan; Chang, Tsung-Wei; Yang, Chan-Tsung; Lai, Yu-Shu; Cheng, Cheng-Kung

2011-10-01

The post-cam design of contemporary posterior stabilized knee prosthesis can be categorized into flat-on-flat or curve-on-curve contact surfaces. The curve-on-curve design has been demonstrated its advantage of reducing stress concentration when the knee sustained an anteroposterior force with tibial rotation. How the post-cam design affects knee kinematics is still unknown, particularly, to compare the difference between the two design features. Analyzing knee kinematics of posterior stabilized knee prosthesis with various post-cam designs should provide certain instructions to the modification of prosthesis design. A dynamic knee model was utilized to investigate tibiofemoral motion of various post-cam designs during high knee flexion. Two posterior stabilized knee models were constructed with flat-on-flat and curve-on-curve contact surfaces of post-cam. Dynamic data of axial tibial rotation and femoral translation were measured from full-extension to 135°. Internal tibial rotation increased with knee flexion in both designs. Before post-cam engagement, the magnitude of internal tibial rotation was close in the two designs. However, tibial rotation angle decreased beyond femoral cam engaged with tibial post. The rate of reduction of tibial rotation was relatively lower in the curve-on-curve design. From post-cam engagement to extreme flexion, the curve-on-curve design had greater internal tibial rotation. Motion constraint was generated by medial impingement of femoral cam on tibial post. It would interfere with the axial motion of the femur relative to the tibia, resulting in decrease of internal tibial rotation. Elimination of rotational constraint should be necessary for achieving better tibial rotation during high knee flexion. Copyright © 2011 Elsevier Ltd. All rights reserved.

Canine stifle joint biomechanics associated with tibial plateau leveling osteotomy predicted by use of a computer model.

PubMed

Brown, Nathan P; Bertocci, Gina E; Marcellin-Little, Denis J

2014-07-01

To evaluate effects of tibial plateau leveling osteotomy (TPLO) on canine stifle joint biomechanics in a cranial cruciate ligament (CrCL)-deficient stifle joint by use of a 3-D computer model simulating the stance phase of gait and to compare biomechanics in TPLO-managed, CrCL-intact, and CrCL-deficient stifle joints. Computer simulations of the pelvic limb of a Golden Retriever. A previously developed computer model of the canine pelvic limb was used to simulate TPLO stabilization to achieve a tibial plateau angle (TPA) of 5° (baseline value) in a CrCL-deficient stifle joint. Sensitivity analysis was conducted for tibial fragment rotation of 13° to -3°. Ligament loads, relative tibial translation, and relative tibial rotation were determined and compared with values for CrCL-intact and CrCL-deficient stifle joints. TPLO with a 5° TPA converted cranial tibial translation to caudal tibial translation and increased loads placed on the remaining stifle joint ligaments, compared with results for a CrCL-intact stifle joint. Lateral collateral ligament load was similar, medial collateral ligament load increased, and caudal cruciate ligament load decreased after TPLO, compared with loads for a CrCL-deficient stifle joint. Relative tibial rotation after TPLO was similar to that of a CrCL-deficient stifle joint. Stifle joint biomechanics were affected by TPLO fragment rotation. In the model, stifle joint biomechanics were partially improved after TPLO, compared with CrCL-deficient stifle joint biomechanics, but TPLO did not fully restore CrCL-intact stifle joint biomechanics. Overrotation of the tibial fragment negatively influenced stifle joint biomechanics by increasing caudal tibial translation.

Management of combined knee medial compartmental and patellofemoral osteoarthritis with lateral closing wedge osteotomy with anterior translation of the distal tibial fragment: Does the degree of anteriorization affect the functional outcome and posterior tibial slope?

PubMed

Sadek, Ahmed F; Osman, Mohammed K; Laklok, Mohamed A

2016-10-01

The aim of this study was to assess the effect of degree of anterior translation of the distal tibial fragment after lateral closing wedge high tibial osteotomy in patients having combined knee medial compartmental and patellofemoral osteoarthritis. A retrospective study was conducted on 64 patients who were operated on for combined knee medial compartmental and patellofemoral osteoarthritis, by lateral closing wedge high tibial osteotomy with anterior translation of the distal tibial fragment. They were divided into two groups; Group I comprising 32 patients (34 knees, mean age of 51.4±7years) whose degree of anterior translation was <1cm and Group II comprising 32 patients (33 knees, mean age of 52.2±8.3years) whose degree of anterior translation was >1.5cm. The final assessment was performed via: visual analog scale, postoperative Knee Society clinical rating system function score, active range of motion, time to union, degree of correction of mechanical axis, posterior tibial slope, and Insall-Salvati ratio. Group II patients exhibited statistically superior mean postoperative score and better return to their work than Group I (P=0.013, 0.076, respectively). Both groups showed statistically significant differences between the preoperative and postoperative evaluation parameters (P<0.001). The posterior tibial slope was decreased in both groups but with no significant difference (P=0.527). Lateral closing wedge high tibial osteotomy combined with anterior translation of the distal tibial fragment more than 1.5cm achieved significantly better postoperative functional knee score. Both groups exhibited comparatively decreased posterior tibial slope. Copyright © 2016 Elsevier B.V. All rights reserved.

Standing balance in people with trans-tibial amputation due to vascular causes: A literature review.

PubMed

Seth, Mayank; Lamberg, Eric

2017-08-01

Balance is an important variable to consider during the rehabilitation process of individuals with trans-tibial amputation. Limited evidence exists on the balance abilities of people with trans-tibial amputation due to vascular causes. The purpose of this article is to review literature and determine if standing balance is diminished in people with trans-tibial amputation due to vascular causes. Literature review. Data were obtained from PubMed, Google Scholar, OandP.org , CINHAL, and Science Direct. Studies were selected only if they included standing balance assessment of people with unilateral trans-tibial amputation due to vascular causes. The review yielded seven articles that met the inclusion criteria. The general test methodology required participants to stand still on force platforms, with feet together, while center of pressure or postural sway was recorded. According to the findings of this review, individuals with trans-tibial amputees due to vascular causes have diminished balance abilities. Limited evidence suggests their balance might be further diminished as compared to individuals with trans-tibial amputation due to trauma. Although the evidence is limited, because of the underlying pathology and presence of comorbidities in individuals with trans-tibial amputation due to vascular causes, one cannot ignore these findings, as even a minor injury from a fall may develop into a non-healing ulcer and affect their health and well-being more severely than individuals with trans-tibial amputation due to trauma. Clinical relevance Individuals with trans-tibial amputation due to vascular causes have diminished balance abilities compared to healthy individuals and individuals with trans-tibial amputation due to trauma. This difference should be considered when designing and fabricating prostheses. Prosthetists and rehabilitation clinicians should consider designing amputation cause-specific rehabilitation interventions, focussing on balance and other functional limitations related to comorbidities of amputation.

Intraoperative study on anthropometry and gender differences of the proximal tibial plateau at the arthroplasty resection surface.

PubMed

Yang, Bo; Yu, Jiakuo; Gong, Xi; Chen, Lianxu; Wang, Yongjian; Wang, Jian; Wang, Haijun; Zhang, Jiying

2014-01-01

The tibial plateau is asymmetric with a larger medial plateau. We observed from clinical practice that the shape of the tibial plateau does not always present a larger medial plateau. Tibial plateau also showed other shapes. The purpose of this study was to analyze the anthropometric data of the proximal tibia in a large group of Chinese patients undergoing total knee arthroplasty and to investigate the morphology of the resected proximal tibial surface and its gender differences. A total of 822 knees (164 males, 658 females) from the Chinese population were measured intraoperatively for medial anteroposterior (MAP) and lateral anteroposterior (LAP) dimensions of the resected proximal tibial surface. The difference of MAP and LAP (DML) was also calculated as MAP minus LAP. We then classified the data into three groups based on the DML (<-2, -2 to 2, and >2 mm) to analyze the morphology of the proximal tibia and its distribution between male and female. The shape of proximal tibial plateau was of three types: larger medial plateau type, symmetric type, and larger lateral plateau type. There were significant differences between males and females in relation to the shape distribution of the proximal tibial plateau (P < 0.05). Most of the proximal tibial plateau was asymmetric, with 517 of 822 (62.9%) tibia having a DML >2 mm and 120 of 822 (14.6%) tibia having a DML<-2 mm. Only 185 of 822 (22.5%) tibia had a DML between -2 and 2 mm. The results of this study can be used as a guideline to design tibial components with different DMLs to better match the different anthropometry of the resected tibial surface.

Theoretical discrepancy between cage size and efficient tibial tuberosity advancement in dogs treated for cranial cruciate ligament rupture.

PubMed

Etchepareborde, S; Mills, J; Busoni, V; Brunel, L; Balligand, M

2011-01-01

To calculate the difference between the desired tibial tuberosity advancement (TTA) along the tibial plateau axis and the advancement truly achieved in that direction when cage size has been determined using the method of Montavon and colleagues. To measure the effect of this difference on the final patellar tendon-tibial plateau angle (PTA) in relation to the ideal 90°. Trigonometry was used to calculate the theoretical actual advancement of the tibial tuberosity in a direction parallel to the tibial plateau that would be achieved by the placement of a cage at the level of the tibial tuberosity in the osteotomy plane of the tibial crest. The same principle was used to calculate the size of the cage that would have been required to achieve the desired advancement. The effect of the difference between the desired advancement and the actual advancement achieved on the final PTA was calculated. For a given desired advancement, the greater the tibial plateau angle (TPA), the greater the difference between the desired advancement and the actual advancement achieved. The maximum discrepancy calculated was 5.8 mm for a 12 mm advancement in a case of extreme TPA (59°). When the TPA was less than 31°, the PTA was in the range of 90° to 95°. A discrepancy does exist between the desired tibial tuberosity advancement and the actual advancement in a direction parallel to the TPA, when the tibial tuberosity is not translated proximally. Although this has an influence on the final PTA, further studies are warranted to evaluate whether this is clinically significant.

Comparison of intraoperative anthropometric measurements of the proximal tibia and tibial component in total knee arthroplasty.

PubMed

Miyatake, Naohisa; Sugita, Takehiko; Aizawa, Toshimi; Sasaki, Akira; Maeda, Ikuo; Kamimura, Masayuki; Fujisawa, Hirokazu; Takahashi, Atsushi

2016-09-01

Precise matching of the tibial component and resected bony surfaces and proper rotational implanting of the tibial component are crucial for successful total knee arthroplasty. We aimed to analyze the exact anthropometric proximal tibial data of Japanese patients undergoing total knee arthroplasty and correlate the measurements with the dimensions of current total knee arthroplasty systems. A total of 703 knees in 566 Japanese patients who underwent total knee arthroplasty for osteoarthritis were included. The bone resection in the proximal tibia was performed perpendicular to the tibial axis in the frontal plane. Measurements of the proximal tibia were intraoperatively obtained after proximal tibial preparation. There were significant positive correlations between the lateral anteroposterior and medial anteroposterior and mediolateral dimensions. A progressive decrease in the mediolateral/lateral anteroposterior ratio with an increasing lateral anteroposterior dimension or the mediolateral/anteroposterior ratio with an increasing anteroposterior dimension was observed. The lateral anteroposterior dimension was smaller than the medial anteroposterior dimension by a mean of 4.8 ± 2.0 mm. The proximal tibia exhibited asymmetry between the lateral and medial plateaus. A comparison of the morphological data and dimensions of the implants, one of which was a symmetric tibial component (NexGen) and the others were asymmetric (Genesis II and Persona), indicated that an asymmetric tibial component could be beneficial to maximize tibial plateau coverage. This study provided important reference data for designing a proper tibial component for Japanese people. The proximal tibial cut surface was asymmetric. There was wide dispersion in the lateral anteroposterior, medial anteroposterior, and mediolateral dimensions depending on the patient. Our data showed that the tibial components of the Genesis II and Persona rather than that of the NexGen may be preferable for Japanese people because of their asymmetric design. Copyright © 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

Interaction of arch type and footwear on running mechanics.

PubMed

Butler, Robert J; Davis, Irene S; Hamill, Joseph

2006-12-01

Running shoes are designed to accommodate various arch types to reduce the risk of lower extremity injuries sustained during running. Yet little is known about the biomechanical changes of running in the recommended footwear that may allow for a reduction in injuries. To evaluate the effects of motion control and cushion trainer shoes on running mechanics in low- and high-arched runners. Controlled laboratory study. Twenty high-arched and 20 low-arched recreational runners (>10 miles per week) were recruited for the study. Three-dimensional kinematic and kinetics were collected as subjects ran at 3.5 ms(-1) +/- 5% along a 25-m runway. The motion control shoe evaluated was the New Balance 1122, and the cushioning shoe evaluated was the New Balance 1022. Repeated-measures analyses of variance were used to determine if low- and high-arched runners responded differently to motion control and cushion trainer shoes. A significant interaction was observed in the instantaneous loading rate such that the low-arched runners had a lower instantaneous loading rate in the motion control condition, and the high-arched runners had a lower instantaneous loading rate in the cushion trainer condition. Significant main effects for shoe were observed for peak positive tibial acceleration, peak-to-peak tibial acceleration, mean loading rate, peak eversion, and eversion excursion. These results suggest that motion control shoes control rearfoot motion better than do cushion trainer shoes. In addition, cushion trainer shoes attenuate shock better than motion control shoes do. However, with the exception of instantaneous loading rate, these benefits do not differ between arch type. Running footwear recommendations should be based on an individual's running mechanics. If a mechanical analysis is not available, footwear recommendations can be based empirically on the individual's arch type.

Standardized pivot shift test improves measurement accuracy.

PubMed

Hoshino, Yuichi; Araujo, Paulo; Ahlden, Mattias; Moore, Charity G; Kuroda, Ryosuke; Zaffagnini, Stefano; Karlsson, Jon; Fu, Freddie H; Musahl, Volker

2012-04-01

The variability of the pivot shift test techniques greatly interferes with achieving a quantitative and generally comparable measurement. The purpose of this study was to compare the variation of the quantitative pivot shift measurements with different surgeons' preferred techniques to a standardized technique. The hypothesis was that standardizing the pivot shift test would improve consistency in the quantitative evaluation when compared with surgeon-specific techniques. A whole lower body cadaveric specimen was prepared to have a low-grade pivot shift on one side and high-grade pivot shift on the other side. Twelve expert surgeons performed the pivot shift test using (1) their preferred technique and (2) a standardized technique. Electromagnetic tracking was utilized to measure anterior tibial translation and acceleration of the reduction during the pivot shift test. The variation of the measurement was compared between the surgeons' preferred technique and the standardized technique. The anterior tibial translation during pivot shift test was similar between using surgeons' preferred technique (left 24.0 ± 4.3 mm; right 15.5 ± 3.8 mm) and using standardized technique (left 25.1 ± 3.2 mm; right 15.6 ± 4.0 mm; n.s.). However, the variation in acceleration was significantly smaller with the standardized technique (left 3.0 ± 1.3 mm/s(2); right 2.5 ± 0.7 mm/s(2)) compared with the surgeons' preferred technique (left 4.3 ± 3.3 mm/s(2); right 3.4 ± 2.3 mm/s(2); both P < 0.01). Standardizing the pivot shift test maneuver provides a more consistent quantitative evaluation and may be helpful in designing future multicenter clinical outcome trials. Diagnostic study, Level I.

Biomechanical and functional indicators in male semiprofessional soccer players with increased hip alpha angles vs. amateur soccer players.

PubMed

Lahner, Matthias; von Schulze Pellengahr, Christoph; Walter, Philipp Alexander; Lukas, Carsten; Falarzik, Andreas; Daniilidis, Kiriakos; von Engelhardt, Lars Victor; Abraham, Christoph; Hennig, Ewald M; Hagen, Marco

2014-03-16

Femoroacetabular impingement (FAI) is predominant in young male athletes, but not much is known about gait differences in cases of increased hip alpha angles. In our study, the hip alpha angle of Nötzli of soccer players was quantified on the basis of magnetic resonance imaging (MRI) with axial oblique sequences. The aim of the current study was to compare the rearfoot motion and plantar pressure in male semiprofessional soccer players with increased alpha angles to age-matched amateur soccer players. In a prospective analysis, male semiprofessional and amateur soccer players had an MRI of the right hip to measure the alpha angle of Nötzli. In a biomechanical laboratory setting, 14 of these participants in each group ran in two shoe conditions. Simultaneously in-shoe pressure distribution, tibial acceleration, and rearfoot motion measurements of the right foot were performed. In the semiprofessional soccer group, the mean value of the alpha angle of group was 55.1 ± 6.58° (range 43.2-76.6°) and 51.6 ± 4.43° (range 41.9-58.8°) in the amateur group. In both shoe conditions, we found a significant difference between the two groups concerning the ground reaction forces, tibial acceleration, rearfoot motion and plantar pressure parameters (P < 0.01, P < 0.05, P = 0.04). Maximum rearfoot motion is about 22% lower in the semiprofessional group compared to the amateur group in both shoe conditions. This study confirmed that semiprofessional soccer players with increased alpha angles showed differences in gait kinematics compared to the amateur group. These findings support the need for a screening program for competitive soccer players. In cases of a conspicuous gait analysis and symptomatic hip pain, FAI must be ruled out by further diagnostic tests.

Influence of tibial shock feedback training on impact loading and running economy.

PubMed

Clansey, Adam Charles; Hanlon, Michael; Wallace, Eric S; Nevill, Alan; Lake, Mark J

2014-01-01

The purpose of this study was to determine whether real-time feedback (RTF) training would reduce impact loading variables previously linked with tibial stress fracture risk and whether these adaptations would influence running economy. Twenty-two male runners were randomly assigned to RTF (n = 12) and control (n = 10) groups. The RTF group received feedback based on their peak tibial axial accelerations (PTA) during six 20-min treadmill runs for 3 wk, whereas the control group adhered to the same training but without feedback. Unilateral three-dimensional kinematic and kinetic analysis and running economy measurements were conducted before, after, and at 1 month posttraining. The RTF group had significant reductions (P < 0.01) in PTA and average and instantaneous vertical force loading rates after training as compared with no changes in the control group. These modifications in impact loads were only maintained in PTA 1 month after the training. A significant increase (P = 0.0033) in ankle plantarflexion at initial contact and a significant change (P = 0.030) in foot strike pattern from a rearfoot to midfoot strike pattern and a significant decrease (P = 0.008) in heel vertical velocity at initial contact appeared to be the primary mechanical strategies adopted by runners to reduce impact loading after RTF training. Despite these gait adaptations, running economy was unaffected. The results of this study suggest that gait retraining using RTF is an effective means of eliciting reductions in impact loading without negatively affecting running economy. However, with loading rate reductions not being maintained 1 month posttraining, further research is required to determine how these reductions in impact severity can be retained long term.

Management of tibial non-unions according to a novel treatment algorithm.

PubMed

Ferreira, Nando; Marais, Leonard Charles

2015-12-01

Tibial non-unions represent a spectrum of conditions that are challenging to treat. The optimal management remains unclear despite the frequency with which these diagnoses are encountered. The aim of this study was to determine the outcome of tibial non-unions managed according to a novel tibial non-union treatment algorithm. One hundred and eighteen consecutive patients with 122 uninfected tibial non-unions were treated according to our proposed tibial non-union treatment algorithm. All patients were followed-up clinically and radiologically for a minimum of six months after external fixator removal. Four patients were excluded because they did not complete the intended treatment process. The final study population consisted of 94 men and 24 women with a mean age of 34 years. Sixty-seven non-unions were stiff hypertrophic, 32 mobile atrophic, 16 mobile oligotrophic and one true pseudoarthrosis. Six non-unions were classified as type B1 defect non-unions. Bony union was achieved after the initial surgery in 113/122 (92.6%) tibias. Nine patients had failure of treatment. Seven persistent non-unions were successfully retreated according to the tibial non-union treatment algorithm. This resulted in final bony union in 120/122 (98.3%) tibias. The proposed tibial non-union treatment algorithm appears to produce high union rates across a diverse group of tibial non-unions. Tibial non-unions however, remain difficult to treat and should be referred to specialist units where advanced reconstructive techniques are practiced on a regular basis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of tibial slope on the stability of the anterior cruciate ligament-deficient knee.

PubMed

Voos, James E; Suero, Eduardo M; Citak, Musa; Petrigliano, Frank P; Bosscher, Marianne R F; Citak, Mustafa; Wickiewicz, Thomas L; Pearle, Andrew D

2012-08-01

We aimed to quantify the effect of changes in tibial slope on the magnitude of anterior tibial translation (ATT) in the anterior cruciate ligament (ACL)-deficient knee during the Lachman and mechanized pivot shift tests. We hypothesized that increased posterior tibial slope would increase the amount of ATT of an ACL-deficient knee, while leveling the slope of the tibial plateau would decrease the amount of ATT. Lachman and mechanized pivot shift tests were performed on hip-to-toe cadaveric specimens, and ATT of the lateral and the medial compartments was measured using navigation (n = 11). The ACL was then sectioned. Stability testing was repeated, and ATT was recorded. A proximal tibial osteotomy in the sagittal plane was then performed achieving either +5 or -5° of tibial slope variation after which stability testing was repeated (n = 10). Sectioning the ACL resulted in a significant increase in ATT in both the Lachman and mechanized pivot shift tests (P < 0.05). Increasing or decreasing the slope of the tibial plateau had no effect on ATT during the Lachman test (n.s.). During the mechanized pivot shift tests, a 5° increase in posterior slope resulted in a significant increase in ATT compared to the native knee (P < 0.05), while a 5° decrease in slope reduced ATT to a level similar to that of the intact knee. Tibial slope changes did not affect the magnitude of translation during a Lachman test. However, large changes in tibial slope variation affected the magnitude of the pivot shift.

[The geometry of the keel determines the behaviour of the tibial tray against torsional forces in total knee replacement].

PubMed

García David, S; Cortijo Martínez, J A; Navarro Bermúdez, I; Maculé, F; Hinarejos, P; Puig-Verdié, L; Monllau, J C; Hernández Hermoso, J A

2014-01-01

The keel design of the tibial tray is essential for the transmission of the majority of the forces to the peripheral bone structures, which have better mechanical proprieties, thus reducing the risk of loosening. The aim of the present study was to compare the behaviour of different tibial tray designs submitted to torsional forces. Four different tibial components were modelled. The 3-D reconstruction was made using the Mimics software. The solid elements were generated by SolidWorks. The finite elements study was done by Unigraphics. A torsional force of 6 Nm. applied to the lateral aspects of each tibial tray was simulated. The GENUTECH® tibial tray, with peripheral trabecular bone support, showed a lower displacement and less transmitted tensions under torsional forces. The results suggest that a tibial tray with more peripheral support behaves mechanically better than the other studied designs. Copyright © 2013 SECOT. Published by Elsevier Espana. All rights reserved.

Increases in tibial force imbalance but not changes in tibiofemoral laxities are caused by varus-valgus malalignment of the femoral component in kinematically aligned TKA.

PubMed

Riley, Jeremy; Roth, Joshua D; Howell, Stephen M; Hull, Maury L

2018-01-29

The purposes of this study were to quantify the increase in tibial force imbalance (i.e. magnitude of difference between medial and lateral tibial forces) and changes in laxities caused by 2° and 4° of varus-valgus (V-V) malalignment of the femoral component in kinematically aligned total knee arthroplasty (TKA) and use the results to detemine sensitivities to errors in making the distal femoral resections. Because V-V malalignment would introduce the greatest changes in the alignment of the articular surfaces at 0° flexion, the hypotheses were that the greatest increases in tibial force imbalance would occur at 0° flexion, that primarily V-V laxity would significantly change at this flexion angle, and that the tibial force imbalance would increase and laxities would change in proportion to the degree of V-V malalignment. Kinematically aligned TKA was performed on ten human cadaveric knee specimens using disposable manual instruments without soft tissue release. One 3D-printed reference femoral component, with unmodified geometry, was aligned to restore the native distal and posterior femoral joint lines. Four 3D-printed femoral components, with modified geometry, introduced V-V malalignments of 2° and 4° from the reference component. Medial and lateral tibial forces were measured during passive knee flexion-extension between 0° to 120° using a custom tibial force sensor. Eight laxities were measured from 0° to 120° flexion using a six degree-of-freedom load application system. With the tibial component kinematically aligned, the increase in the tibial force imbalance from that of the reference component at 0° of flexion was sensitive to the degree of V-V malalignment of the femoral component. Sensitivities were 54 N/deg (medial tibial force increasing > lateral tibial force) (p < 0.0024) and 44 N/deg (lateral tibial force increasing > medial tibial force) (p < 0.0077) for varus and valgus malalignments, respectively. Varus-valgus malalignment did not significantly change varus, internal-external rotation, anterior-posterior, and compression-distraction laxities from 0° to 120° flexion. At only 30° of flexion, 4° of varus malalignment increased valgus laxity 1° (p = 0.0014). At 0° flexion, V-V malalignment of the femoral component caused the tibial force imbalance to increase significantly, whereas the laxities were relatively unaffected. Because tibial force imbalance has the potential to adversely affect patient-reported outcomes and satisfaction, surgeons should strive to limit errors in resecting the distal femoral condyles to within ± 0.5 mm which in turn limits the average increase in tibial force imbalance to 68 N. Because laxities were generally unaffected, instability resulting from large increases in laxity is not a clinical concern within the ± 4° range tested. Therapeutic, Level II.

Internal-external malalignment of the femoral component in kinematically aligned total knee arthroplasty increases tibial force imbalance but does not change laxities of the tibiofemoral joint.

PubMed

Riley, Jeremy; Roth, Joshua D; Howell, Stephen M; Hull, Maury L

2018-06-01

The purposes of this study were to quantify the increase in tibial force imbalance (i.e. magnitude of difference between medial and lateral tibial forces) and changes in laxities caused by  2° and 4° of internal-external (I-E) malalignment of the femoral component in kinematically aligned total knee arthroplasty. Because I-E malalignment would introduce the greatest changes to the articular surfaces near 90° of flexion, the hypotheses were that the tibial force imbalance would be significantly increased near 90° flexion and that primarily varus-valgus laxity would be affected near 90° flexion. Kinematically aligned TKA was performed on ten human cadaveric knee specimens using disposable manual instruments without soft tissue release. One 3D-printed reference femoral component, with unmodified geometry, was aligned to restore the native distal and posterior femoral joint lines. Four 3D-printed femoral components, with modified geometry, introduced I-E malalignments of 2° and 4° from the reference component. Medial and lateral tibial forces were measured from 0° to 120° flexion using a custom tibial force sensor. Bidirectional laxities in four degrees of freedom were measured from 0° to 120° flexion using a custom load application system. Tibial force imbalance increased the greatest at 60° flexion where a regression analysis against the degree of I-E malalignment yielded sensitivities (i.e. slopes) of 30 N/° (medial tibial force > lateral tibial force) and 10 N/° (lateral tibial force > medial tibial force) for internal and external malalignments, respectively. Valgus laxity increased significantly with the 4° external component with the greatest increase of 1.5° occurring at 90° flexion (p < 0.0001). With the tibial component correctly aligned, I-E malalignment of the femoral component caused significant increases in tibial force imbalance. Minimizing I-E malalignment lowers the increase in the tibial force imbalance. By keeping the resection thickness of each posterior femoral condyle to within ± 0.5 mm of the thickness of the respective posterior region of the femoral component, the increase in imbalance can be effectively limited to 38 N. Generally laxities were unaffected within the ± 4º range tested indicating that instability is not a clinical concern and that manual testing of laxities is not useful to detect I-E malalignment.

High-resolution axial MR imaging of tibial stress injuries

PubMed Central

2012-01-01

Purpose To evaluate the relative involvement of tibial stress injuries using high-resolution axial MR imaging and the correlation with MR and radiographic images. Methods A total of 33 patients with exercise-induced tibial pain were evaluated. All patients underwent radiograph and high-resolution axial MR imaging. Radiographs were taken at initial presentation and 4 weeks later. High-resolution MR axial images were obtained using a microscopy surface coil with 60 × 60 mm field of view on a 1.5T MR unit. All images were evaluated for abnormal signals of the periosteum, cortex and bone marrow. Results Nineteen patients showed no periosteal reaction at initial and follow-up radiographs. MR imaging showed abnormal signals in the periosteal tissue and partially abnormal signals in the bone marrow. In 7 patients, periosteal reaction was not seen at initial radiograph, but was detected at follow-up radiograph. MR imaging showed abnormal signals in the periosteal tissue and entire bone marrow. Abnormal signals in the cortex were found in 6 patients. The remaining 7 showed periosteal reactions at initial radiograph. MR imaging showed abnormal signals in the periosteal tissue in 6 patients. Abnormal signals were seen in the partial and entire bone marrow in 4 and 3 patients, respectively. Conclusions Bone marrow abnormalities in high-resolution axial MR imaging were related to periosteal reactions at follow-up radiograph. Bone marrow abnormalities might predict later periosteal reactions, suggesting shin splints or stress fractures. High-resolution axial MR imaging is useful in early discrimination of tibial stress injuries. PMID:22574840

Segmental transports for posttraumatic lower extremity bone defects: are femoral bone transports safer than tibial?

PubMed

Liodakis, Emmanouil; Kenawey, Mohamed; Krettek, Christian; Ettinger, Max; Jagodzinski, Michael; Hankemeier, Stefan

2011-02-01

The long-term outcomes following femoral and tibial segment transports are not well documented. Purpose of the study is to compare the complication rates and life quality scores of femoral and tibial transports in order to find what are the complication rates of femoral and tibial monorail bone transports and if they are different? We retrospectively analyzed the medical records of 8 femoral and 14 tibial consecutive segment transports performed with the monorail technique between 2001 and 2008 in our institution. Mean follow-up was 5.1 ± 2.1 years with a minimum follow-up of 2 years. Aetiology of the defects was posttraumatic in all cases. Four femoral (50%) and nine tibial (64%) fractures were open. The Short Form-36 (SF-36) health survey was used to compare the life quality after femoral and tibial bone transports. The Mann-Whiney U test, Fisher exact test, and the Student's two tailed t-test were used for statistical analysis. P ≤ 0.05 was considered to be statistically significant. The tibial transport was associated with higher rates of severe complications and additional procedures (1.5 ± 0.9 vs. 3.4 ± 2.7, p = 0.048). Three patients of the tibial group were amputated because of recurrent infections and one developed a complete regenerate insufficiency that was treated with partial diaphyseal tibial replacement. Contrary to that none of patients of the femoral group developed a complete regenerate insufficiency or was amputated. Tibial bone transports have a higher rate of complete and incomplete regenerate insufficiency and can more often end in an amputation. The authors suggest systematic weekly controls of the CRP value and of the callus formation in patients with posttraumatic tibia bone transports. Further comparative studies comparing the results of bone transports with and without intramedullary implants are necessary.

Minimizing Alteration of Posterior Tibial Slope During Opening Wedge High Tibial Osteotomy: a Protocol with Experimental Validation in Paired Cadaveric Knees

PubMed Central

Westermann, Robert W; DeBerardino, Thomas; Amendola, Annunziato

2014-01-01

Introduction The High Tibial Osteotomy (HTO) is a reliable procedure in addressing uni- compartmental arthritis with associated coronal deformities. With osteotomy of the proximal tibia, there is a risk of altering the tibial slope in the sagittal plane. Surgical techniques continue to evolve with trends towards procedure reproducibility and simplification. We evaluated a modification of the Arthrex iBalance technique in 18 paired cadaveric knees with the goals of maintaining sagittal slope, increasing procedure efficiency, and decreasing use of intraoperative fluoroscopy. Methods Nine paired cadaveric knees (18 legs) underwent iBalance medial opening wedge high tibial osteotomies. In each pair, the right knee underwent an HTO using the modified technique, while all left knees underwent the traditional technique. Independent observers evaluated postoperative factors including tibial slope, placement of hinge pin, and implant placement. Specimens were then dissected to evaluate for any gross muscle, nerve or vessel injury. Results Changes to posterior tibial slope were similar using each technique. The change in slope in traditional iBalance technique was -0.3° ±2.3° and change in tibial slope using the modified iBalance technique was -0.4° ±2.3° (p=0.29). Furthermore, we detected no differences in posterior tibial slope between preoperative and postoperative specimens (p=0.74 traditional, p=0.75 modified). No differences in implant placement were detected between traditional and modified techniques. (p=0.85). No intraoperative iatrogenic complications (i.e. lateral cortex fracture, blood vessel or nerve injury) were observed in either group after gross dissection. Discussion & Conclusions Alterations in posterior tibial slope are associated with HTOs. Both traditional and modified iBalance techniques appear reliable in coronal plane corrections without changing posterior tibial slope. The present modification of the Arthrex iBalance technique may increase the efficiency of the operation and decrease radiation exposure to patients without compromising implant placement or global knee alignment. PMID:25328454

Increased revision rate with posterior tibial tunnel placement after using the 70-degree tibial guide in ACL reconstruction.

PubMed

Inderhaug, Eivind; Raknes, Sveinung; Østvold, Thomas; Solheim, Eirik; Strand, Torbjørn

2017-01-01

To map knee morphology radiographically in a population with a torn ACL and to investigate whether anatomic factors could be related to outcomes after ACL reconstruction at mid- to long-term follow-up. Further, we wanted to assess tibial tunnel placement after using the 70-degree "anti-impingement" tibial tunnel guide and investigate any relation between tunnel placement and revision surgery. Patients undergoing ACL reconstruction involving the 70-degree tibial guide from 2003 to 2008 were included. Two independent investigators analysed pre- and post-operative radiographs. Demographic data and information on revision surgery were collected from an internal database. Anatomic factors and post-operative tibial tunnel placements were investigated as predictors of revision. Three-hundred and seventy-seven patients were included in the study. A large anatomic variation with significant differences between men and women was seen. None of the anatomic factors could be related to a significant increase in revision rate. Patients with a posterior tibial tunnel placement, defined as 50 % or more posterior on the Amis and Jakob line, did, however, have a higher risk of revision surgery compared to patients with an anterior tunnel placement (P = 0.03). Use of the 70-degree tibial guide did result in a high incidence (47 %) of posterior tibial tunnel placements associated with an increased rate of revision surgery. The current study was, however, not able to identify any anatomic variation that could be related to a higher risk of revision surgery. Avoiding graft impingement from the femoral roof in anterior tibial tunnel placements is important, but the insight that overly posterior tunnel placement can lead to inferior outcome should also be kept in mind when performing ACL surgery. IV.

Influence of the posterior tibial slope on the flexion gap in total knee arthroplasty.

PubMed

Okazaki, Ken; Tashiro, Yasutaka; Mizu-uchi, Hideki; Hamai, Satoshi; Doi, Toshio; Iwamoto, Yukihide

2014-08-01

Adjusting the joint gap length to be equal in both extension and flexion is an important issue in total knee arthroplasty (TKA). It is generally acknowledged that posterior tibial slope affects the flexion gap; however, the extent to which changes in the tibial slope angle directly affect the flexion gap remains unclear. This study aimed to clarify the influence of tibial slope changes on the flexion gap in cruciate-retaining (CR) or posterior-stabilizing (PS) TKA. The flexion gap was measured using a tensor device with the femoral trial component in 20 cases each of CR- and PS-TKA. A wedge plate with a 5° inclination was placed on the tibial cut surface by switching its front-back direction to increase or decrease the tibial slope by 5°. The flexion gap after changing the tibial slope was compared to that of the neutral slope measured with a flat plate that had the same thickness as that of the wedge plate center. When the tibial slope decreased or increased by 5°, the flexion gap decreased or increased by 1.9 ± 0.6mm or 1.8 ± 0.4mm, respectively, with CR-TKA and 1.2 ± 0.4mm or 1.1 ± 0.3mm, respectively, with PS-TKA. The influence of changing the tibial slope by 5° on the flexion gap was approximately 2mm with CR-TKA and 1mm with PS-TKA. This information is useful when considering the effect of manipulating the tibial slope on the flexion gap when performing CR- or PS-TKA. Copyright © 2014 Elsevier B.V. All rights reserved.

An Improved Tibial Force Sensor to Compute Contact Forces and Contact Locations In Vitro After Total Knee Arthroplasty.

PubMed

Roth, Joshua D; Howell, Stephen M; Hull, Maury L

2017-04-01

Contact force imbalance and contact kinematics (i.e., motion of the contact location in each compartment during flexion) of the tibiofemoral joint are both important predictors of a patient's outcome following total knee arthroplasty (TKA). Previous tibial force sensors have limitations in that they either did not determine contact forces and contact locations independently in the medial and lateral compartments or only did so within restricted areas of the tibial insert, which prevented them from thoroughly evaluating contact force imbalance and contact kinematics in vitro. Accordingly, the primary objective of this study was to present the design and verification of an improved tibial force sensor which overcomes these limitations. The improved tibial force sensor consists of a modified tibial baseplate which houses independent medial and lateral arrays of three custom tension-compression transducers each. This sensor is interchangeable with a standard tibial component because it accommodates tibial articular surface inserts with a range of sizes and thicknesses. This sensor was verified by applying known loads at known locations over the entire surface of the tibial insert to determine the errors in the computed contact force and contact location in each compartment. The root-mean-square errors (RMSEs) in contact force are ≤ 6.1 N which is 1.4% of the 450 N full-scale output. The RMSEs in contact location are ≤ 1.6 mm. This improved tibial force sensor overcomes the limitations of the previous sensors and therefore should be useful for in vitro evaluation of new alignment goals, new surgical techniques, and new component designs in TKA.

Do modern total knee replacements improve tibial coverage?

PubMed

Meier, Malin; Webb, Jonathan; Collins, Jamie E; Beckmann, Johannes; Fitz, Wolfgang

2018-01-25

The purpose of the present study is to compare newer designs of various symmetric and asymmetric tibial components and measure tibial bone coverage using the rotational safe zone defined by two commonly utilized anatomic rotational landmarks. Computed tomography scans (CT scans) of one hundred consecutive patients scheduled for total knee arthroplasty were obtained pre-operatively. A virtual proximal tibial cut was performed and two commonly used rotational axes were added for each image: the medio-lateral axis (ML-axis) and the medial 1/3 tibial tubercle axis (med-1/3-axis). Different symmetric and asymmetric implant designs were then superimposed in various rotational positions for best cancellous and cortical coverage. The images were imported to a public domain imaging software, and cancellous and cortical bone coverage was computed for each image, with each implant design in various rotational positions. One single implant type could not be identified that provided the best cortical and cancellous coverage of the tibia, irrespective of using the med-1/3-axis or the ML-axis for rotational alignment. However, it could be confirmed that the best bone coverage was dependent on the selected rotational landmark. Furthermore, improved bone coverage was observed when tibial implant positions were optimized between the two rotational axes. Tibial coverage is similar for symmetric and asymmetric designs, but depends on the rotational landmark for which the implant is designed. The surgeon has the option to improve tibial coverage by optimizing placement between the two anatomic rotational alignment landmarks, the medial 1/3 and the ML-axis. Surgeons should be careful assessing intraoperative rotational tibial placement using the described anatomic rotational landmarks to optimize tibial bony coverage without compromising patella tracking. III.

Arthroscopic repair of the posterior horn of the medial meniscus with opening wedge high tibial osteotomy: surgical technique.

PubMed

Jung, Kwang Am; Kim, Sung Jae; Lee, Su Chan; Jeong, Jae Hoon; Song, Moon Bok; Lee, Choon Key

2009-07-01

Simultaneous repair of a radial tear at the tibial attachment site of the posterior horn of the medial meniscus under special circumstances requiring tibial valgus osteotomy is technically difficult. First, most patients who need an osteotomy have a narrowed medial tibiofemoral joint space. In such a situation, the pull-out suture technique is more difficult to perform than in a normal joint space. Second, pulling out suture strands that penetrate the posterior horn of the medial meniscus to the anterior tibial cortex increases the risk of transection during osteotomy. We performed a meniscus repair combined with an opening wedge tibial valgus osteotomy without complications and present our technique as a new method for use in selective cases necessitating both meniscus repair of a complete radial tear and opening wedge tibial osteotomy.

Histological Analysis of the Tibial Anterior Cruciate Ligament Insertion

PubMed Central

Siebold, Rainer; Oka, Shinya; Traut, Ulrike; Schuhmacher, Peter; Kirsch, Joachim

2017-01-01

Objective: To describe the morphology of the tibial ACL insertion by histological assessment in the sagittal plane. Methods: For histology the native (undissected) tibial ACL insertion of 6 fresh-frozen cadaveric knees was cut into 4 sagittal sections parallel to the long axis of the medial tibial spine. The slices were stained with hematoxylin and eosin, Safranin O and Russell-Movat pentachrome. All slices were digitalized and analyzed at a magnification of ×20. Results: From medial to lateral the anterior-posterior lengths of the ACL insertion were an average of 10.2, 9.3, 7.6 and 5.8 mm. The anterior margin of the tibial ACL insertion raised from an anterior ridge. The most medial ACL fibers rose along with a peak of the anterior part of the medial tibial spine in which the direct insertion was adjacent to the articular cartilage. Parts of the bony insertions of the anterior and posterior horns of the lateral meniscus were in close contact to the lateral ACL insertion. A small fat pad was located just posterior to the tibial ACL insertion. There were no central or posterolateral inserting ACL fibers in the area intercondylaris anterior. Conclusion: The functional intraligamentous midsubstance ACL fibers arose from the most posterior part of its bony tibial insertion in a flat and “C-shape” way. The anterior border of this functional ACL started from a bony ‘anterior ridge’ and the medial border was along with a peak of the medial tibial spine.

[Repairing of soft tissue defect in leg by free vascularized thoracoumbilical flap with reversed flow].

PubMed

Xu, Y Q; Li, Z Y; Li, J

2000-11-01

To investigate the clinical effect of free vascularized thoracoumbilical flap with reversal flow in repairing the soft tissue defect in leg with tibia exposure. Forty-four casting mould specimens of leg arteries were studied firstly. Then 25 cases with soft tissue defect and tibia exposure in the proximal-middle segment of leg were adopted in this study. Among them, 18 cases had long distance thrombosis of the anterior tibial vessels or posterior tibial vessels due to traumatic lesion. The maximal size of defect was 28 cm x 11 cm and the minimal size of defect was 11 cm x 9 cm. In operation, the thoracoumbilical flap which was based on the inferior epigastric vessels was anastomosed to the distal end of the anterior tibial vessels or posterior tibial vessels. Anterior tibial artery, posterior tibial artery and fibular artery had rich communication branches in foot and ankle. All the flaps survived, the color and cosmetic result of them were good. The free vascularized thoracoumbilical flap with reversed flow is practical in repairing the soft tissue defect of leg with tibia exposure. Either the anterior tibial vessels or the posterior tibial vessels is normal, and the distal end of injured blood vessels is available, this technique can be adopted.

An Innovative Approach to the Repair of Distal Tibia Nonunion Using a Retrograde Buried Tibio-Talar-Calcaneal Nail: A Case Report.

PubMed

Van Steyn, Peter; Romash, Michael

We report a case using retrograde tibial nailing as treatment of nonunion of a distal tibial osteotomy, which was performed as part of a complex reconstruction of distal tibial malunion with ankle arthritis. Although retrograde nailing has classically been used for tibial-talar-calcaneal arthrodesis, this method spares the subtalar joint. Preservation of some hindfoot motion by subtalar mobility allows for a decrease in the loss of function typically seen with tibial-talar-calcaneal arthrodesis. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Tibial rotational osteotomy for idiopathic torsion. A comparison of the proximal and distal osteotomy levels.

PubMed

Krengel, W F; Staheli, L T

1992-10-01

A retrospective analysis was done of 52 rotational tibial osteotomies (RTOs) performed on 35 patients with severe idiopathic tibial torsion. Thirty-nine osteotomies were performed at the proximal or midtibial level. Thirteen were performed at the distal tibial level with a technique previously described by one of the authors. Serious complications occurred in five (13%) of the proximal and in none of the distal RTOs. For severe and persisting idiopathic tibial torsion, the authors recommend correction by RTO at the distal level. Proximal level osteotomy is indicated only when a varus or valgus deformity required concurrent correction.

Tibial lengthening using a humeral intramedullary nail combined with a single-plane external fixator for leg discrepancy in sequelae of poliomyelitis.

PubMed

Chen, Daoyun; Chen, Jianmin; Liu, Fanggang; Jiang, Yao

2011-03-01

The sequelae of poliomyelitis are the common causes of leg discrepancy. Tibial lengthening is an effective way to solve this problem but it is associated with a high rate of complications. In this study, we combined the use of humeral nail and external fixator in tibial lengthening with the purpose of reducing lengthening complications. Compared with the cases lengthened by a single-plane external fixator alone, this combined strategy was found to be beneficial in maintaining the tibial alignment. Therefore, it can be recommended as a good technique for tibial lengthening in patients with sequelae of poliomyelitis.

Relationship between the tibial mechanical axis and bony anatomical landmarks of the calf and foot as measured on radiographs obtained with a new laser-calibrated position.

PubMed

He, Peiheng; Zhu, Qi; Zhang, Zhaohui; Zou, Xuenong; Xu, Dongliang

2013-01-01

To investigate relationship between the tibial mechanical axis and bony landmarks of the calf and foot by developing a new laser-calibrated position for radiography of the lower limb. A total of 120 volunteers were randomly divided into two groups. All subjects were marked with skin projection of the hypothetical axis of the calf on the frontal and sagittal planes. Radiographs of weight-bearing full-length lower-limb were obtained by the laser-calibrated positioning in the experimental group, and by the use of conventional technique in the control group. To consider the rotation of the calf, radiological features of the knee and ankle were investigated. The relationship between the tibial mechanical axis and the bony landmarks of the calf and foot were also measured. Anteroposterior view depicted a tangential projection on the superior/inferior tibiofibular syndesmosis and between lateral malleolus and talus in ankle mortise in the experimental group. Bony overlap on the superior/inferior tibiofibular syndesmosis and between lateral malleolus and talus was seen in control group. On the tangential projection, it also presented a clear wheel-like contour of the medial femoral condyle, but a partial overlap between medial femoral condyle and tibial plateau. The femoral joint angle between the connecting line at the lowest point of the medial and lateral femoral condyles and the tibial mechanical axis was 83.6° ± 2.49° in the experimental group and 85.3° ± 2.18° in the control group (P < 0.001). The tibial tubercle-axis distance from the center of the medial and middle one-third of the tibial tubercle to the tibial mechanical axis was 1.5 mm in the experimental group and 3.7 mm in the control group (P < 0.05). The malleoli-axis distance from the midpoint of the bimalleolar line joining the tips of the medial and lateral malleoli to the tibial mechanical axis was 1.9 mm in the experimental group and 6.9 mm in the control group (P < 0.001). Lateral view showed no difference between the tibial mechanical axis and the fibular reference line within two groups. In the new radiographic position, our data indicate that the hypothetical tibial mechanical axis and fibular reference line, obtained by marking the specified anatomic landmarks of the calf and foot, are located more closely to the tibial mechanical axis by correcting the rotation of the calf and foot during the radiography. On anteroposterior view, the tibial mechanical axis was approximately 2 mm medial to the center of the ankle. This indicates that the hypothetical tibial mechanical axis marked on the skin could be referred to guide the tibial osteotomy in total knee arthroplasty.

Pseudoaneurysm of the Anterior Tibial Artery following Ankle Arthroscopy in a Soccer Player.

PubMed

Tonogai, Ichiro; Matsuura, Tetsuya; Iwame, Toshiyuki; Wada, Keizo; Takasago, Tomoya; Goto, Tomohiro; Hamada, Daisuke; Kawatani, Yohei; Fujimoto, Eiki; Kitagawa, Tetsuya; Takao, Shyoichiro; Iwamoto, Seiji; Yamanaka, Moriaki; Harada, Masafumi; Sairyo, Koichi

2017-01-01

Ankle arthroscopy carries a lower risk of vascular complications when standard anterolateral and anteromedial portals are used. However, the thickness of the fat pad at the anterior ankle affords little protection for the thin-walled anterior tibial artery, rendering it susceptible to indirect damage during procedures performed on the anterior ankle joint. To our knowledge, only 11 cases of pseudoaneurysm involving the anterior tibial artery after ankle arthroscopy have been described in the literature. Here we reported a rare case of a 19-year-old soccer player who presented with pseudoaneurysm of the anterior tibial artery following ankle arthroscopy using an ankle distraction method and underwent anastomosis for the anterior tibial artery injury. Excessive distraction of the ankle puts the neurovascular structures at greater risk for iatrogenic injury of the anterior tibial artery during ankle arthroscopy. Surgeons should look carefully for postoperative ankle swelling and pain after ankle arthroscopy.

Pseudoaneurysm of the Anterior Tibial Artery following Ankle Arthroscopy in a Soccer Player

PubMed Central

Iwame, Toshiyuki; Hamada, Daisuke; Fujimoto, Eiki; Kitagawa, Tetsuya; Takao, Shyoichiro; Iwamoto, Seiji; Yamanaka, Moriaki; Harada, Masafumi

2017-01-01

Ankle arthroscopy carries a lower risk of vascular complications when standard anterolateral and anteromedial portals are used. However, the thickness of the fat pad at the anterior ankle affords little protection for the thin-walled anterior tibial artery, rendering it susceptible to indirect damage during procedures performed on the anterior ankle joint. To our knowledge, only 11 cases of pseudoaneurysm involving the anterior tibial artery after ankle arthroscopy have been described in the literature. Here we reported a rare case of a 19-year-old soccer player who presented with pseudoaneurysm of the anterior tibial artery following ankle arthroscopy using an ankle distraction method and underwent anastomosis for the anterior tibial artery injury. Excessive distraction of the ankle puts the neurovascular structures at greater risk for iatrogenic injury of the anterior tibial artery during ankle arthroscopy. Surgeons should look carefully for postoperative ankle swelling and pain after ankle arthroscopy. PMID:28607785

ACL Roof Impingement Revisited: Does the Independent Femoral Drilling Technique Avoid Roof Impingement With Anteriorly Placed Tibial Tunnels?

PubMed

Tanksley, John A; Werner, Brian C; Conte, Evan J; Lustenberger, David P; Burrus, M Tyrrell; Brockmeier, Stephen F; Gwathmey, F Winston; Miller, Mark D

2017-05-01

Anatomic femoral tunnel placement for single-bundle anterior cruciate ligament (ACL) reconstruction is now well accepted. The ideal location for the tibial tunnel has not been studied extensively, although some biomechanical and clinical studies suggest that placement of the tibial tunnel in the anterior part of the ACL tibial attachment site may be desirable. However, the concern for intercondylar roof impingement has tempered enthusiasm for anterior tibial tunnel placement. To compare the potential for intercondylar roof impingement of ACL grafts with anteriorly positioned tibial tunnels after either transtibial (TT) or independent femoral (IF) tunnel drilling. Controlled laboratory study. Twelve fresh-frozen cadaver knees were randomized to either a TT or IF drilling technique. Tibial guide pins were drilled in the anterior third of the native ACL tibial attachment site after debridement. All efforts were made to drill the femoral tunnel anatomically in the center of the attachment site, and the surrogate ACL graft was visualized using 3-dimensional computed tomography. Reformatting was used to evaluate for roof impingement. Tunnel dimensions, knee flexion angles, and intra-articular sagittal graft angles were also measured. The Impingement Review Index (IRI) was used to evaluate for graft impingement. Two grafts (2/6, 33.3%) in the TT group impinged upon the intercondylar roof and demonstrated angular deformity (IRI type 1). No grafts in the IF group impinged, although 2 of 6 (66.7%) IF grafts touched the roof without deformation (IRI type 2). The presence or absence of impingement was not statistically significant. The mean sagittal tibial tunnel guide pin position prior to drilling was 27.6% of the sagittal diameter of the tibia (range, 22%-33.9%). However, computed tomography performed postdrilling detected substantial posterior enlargement in 2 TT specimens. A significant difference in the sagittal graft angle was noted between the 2 groups. TT grafts were more vertical, leading to angular convergence with the roof, whereas IF grafts were more horizontal and universally diverged from the roof. The IF technique had no specimens with roof impingement despite an anterior tibial tunnel position, likely due to a more horizontal graft trajectory and anatomic placement of the ACL femoral tunnel. Roof impingement remains a concern after TT ACL reconstruction in the setting of anterior tibial tunnel placement, although statistical significance was not found. Future clinical studies are planned to develop better recommendations for ACL tibial tunnel placement. Graft impingement due to excessively anterior tibial tunnel placement using a TT drilling technique has been previously demonstrated; however, this may not be a concern when using an IF tunnel drilling technique. There may also be biomechanical advantages to a more anterior tibial tunnel in IF tunnel ACL reconstruction.

Physeal growth arrest after tibial lengthening in achondroplasia

PubMed Central

2012-01-01

Background and purpose Bilateral tibial lengthening has become one of the standard treatments for upper segment-lower segment disproportion and to improve quality of life in achondroplasia. We determined the effect of tibial lengthening on the tibial physis and compared tibial growth that occurred at the physis with that in non-operated patients with acondroplasia. Methods We performed a retrospective analysis of serial radiographs until skeletal maturity in 23 achondroplasia patients who underwent bilateral tibial lengthening before skeletal maturity (lengthening group L) and 12 achondroplasia patients of similar height and age who did not undergo tibial lengthening (control group C). The mean amount of lengthening of tibia in group L was 9.2 cm (lengthening percentage: 60%) and the mean age at the time of lengthening was 8.2 years. The mean duration of follow-up was 9.8 years. Results Skeletal maturity (fusion of physis) occurred at 15.2 years in group L and at 16.0 years in group C. The actual length of tibia (without distraction) at skeletal maturity was 238 mm in group L and 277 mm in group C (p = 0.03). The mean growth rates showed a decrease in group L relative to group C from about 2 years after surgery. Physeal closure was most pronounced on the anterolateral proximal tibial physis, with relative preservation of the distal physis. Interpretation Our findings indicate that physeal growth rate can be disturbed after tibial lengthening in achondroplasia, and a close watch should be kept for such an occurrence—especially when lengthening of more than 50% is attempted. PMID:22489887

Physeal growth arrest after tibial lengthening in achondroplasia: 23 children followed to skeletal maturity.

PubMed

Song, Sang-Heon; Agashe, Mandar Vikas; Huh, Young-Jae; Hwang, Soon-Young; Song, Hae-Ryong

2012-06-01

Bilateral tibial lengthening has become one of the standard treatments for upper segment-lower segment disproportion and to improve quality of life in achondroplasia. We determined the effect of tibial lengthening on the tibial physis and compared tibial growth that occurred at the physis with that in non-operated patients with achondroplasia. We performed a retrospective analysis of serial radiographs until skeletal maturity in 23 achondroplasia patients who underwent bilateral tibial lengthening before skeletal maturity (lengthening group L) and 12 achondroplasia patients of similar height and age who did not undergo tibial lengthening (control group C). The mean amount of lengthening of tibia in group L was 9.2 cm (lengthening percentage: 60%) and the mean age at the time of lengthening was 8.2 years. The mean duration of follow-up was 9.8 years. Skeletal maturity (fusion of physis) occurred at 15.2 years in group L and at 16.0 years in group C. The actual length of tibia (without distraction) at skeletal maturity was 238 mm in group L and 277 mm in group C (p = 0.03). The mean growth rates showed a decrease in group L relative to group C from about 2 years after surgery. Physeal closure was most pronounced on the anterolateral proximal tibial physis, with relative preservation of the distal physis. Our findings indicate that physeal growth rate can be disturbed after tibial lengthening in achondroplasia, and a close watch should be kept for such an occurrence-especially when lengthening of more than 50% is attempted.

Combined CT-based and image-free navigation systems in TKA reduces postoperative outliers of rotational alignment of the tibial component.

PubMed

Mitsuhashi, Shota; Akamatsu, Yasushi; Kobayashi, Hideo; Kusayama, Yoshihiro; Kumagai, Ken; Saito, Tomoyuki

2018-02-01

Rotational malpositioning of the tibial component can lead to poor functional outcome in TKA. Although various surgical techniques have been proposed, precise rotational placement of the tibial component was difficult to accomplish even with the use of a navigation system. The purpose of this study is to assess whether combined CT-based and image-free navigation systems replicate accurately the rotational alignment of tibial component that was preoperatively planned on CT, compared with the conventional method. We compared the number of outliers for rotational alignment of the tibial component using combined CT-based and image-free navigation systems (navigated group) with those of conventional method (conventional group). Seventy-two TKAs were performed between May 2012 and December 2014. In the navigated group, the anteroposterior axis was prepared using CT-based navigation system and the tibial component was positioned under control of the navigation. In the conventional group, the tibial component was placed with reference to the Akagi line that was determined visually. Fisher's exact probability test was performed to evaluate the results. There was a significant difference between the two groups with regard to the number of outliers: 3 outliers in the navigated group compared with 12 outliers in the conventional group (P < 0.01). We concluded that combined CT-based and image-free navigation systems decreased the number of rotational outliers of tibial component, and was helpful for the replication of the accurate rotational alignment of the tibial component that was preoperatively planned.

Comparison of long-term results between osteo-odonto-keratoprosthesis and tibial bone keratoprosthesis.

PubMed

Charoenrook, Victor; Michael, Ralph; de la Paz, Maria Fideliz; Temprano, José; Barraquer, Rafael I

2018-04-01

To compare the anatomical and the functional results between osteo-odonto-keratoprosthesis (OOKP) and keratoprosthesis using tibial bone autograft (Tibial bone KPro). We reviewed the charts of 258 patients; 145 had OOKP whereas 113 had Tibial bone KPro implanted. Functional success was defined as best corrected visual acuity ≥0.05 on decimal scale and anatomical success as retention of the keratoprosthesis lamina. Kaplan-Meier survival curves were calculated for anatomical and functional survival as well as to estimate the probability of post-op complications. The anatomical survival for both KPro groups was not significantly different and was estimated as 67% for OOKP and 54% for Tibial bone KPro at 10 years after surgery. There was also no difference found after subdividing for primary diagnosis groups such as chemical injury, thermal burn, trachoma and all autoimmune cases combined. Estimated functional survival at 10 years post-surgery was 49% for OOKP and 25% for Tibial bone KPro, which was significantly different. The probability of patients with Tibial bone KPro developing one or more post-operative complications at 10 years after surgery (65%) was significantly higher than those with OOKP (40%). Mucous membrane necrosis and retroprosthetic membrane formation were more common in Tibial bone KPro than OOKP. Both types of autologous biological KPro, OOKP and Tibial bone KPro, had statistically similar rate of keratoprosthesis extrusion. Although functional success rate was significantly higher in OOKP, it may have been influenced by a better visual potential in the patients in this group. Copyright © 2018 Elsevier Inc. All rights reserved.

Measurement of Posterior Tibial Slope Using Magnetic Resonance Imaging.

PubMed

Karimi, Elham; Norouzian, Mohsen; Birjandinejad, Ali; Zandi, Reza; Makhmalbaf, Hadi

2017-11-01

Posterior tibial slope (PTS) is an important factor in the knee joint biomechanics and one of the bone features, which affects knee joint stability. Posterior tibial slope has impact on flexion gap, knee joint stability and posterior femoral rollback that are related to wide range of knee motion. During high tibial osteotomy and total knee arthroplasty (TKA) surgery, proper retaining the mechanical and anatomical axis is important. The aim of this study was to evaluate the value of posterior tibial slope in medial and lateral compartments of tibial plateau and to assess the relationship among the slope with age, gender and other variables of tibial plateau surface. This descriptive study was conducted on 132 healthy knees (80 males and 52 females) with a mean age of 38.26±11.45 (20-60 years) at Imam Reza hospital in Mashhad, Iran. All patients, selected and enrolled for MRI in this study, were admitted for knee pain with uncertain clinical history. According to initial physical knee examinations the study subjects were reported healthy. The mean posterior tibial slope was 7.78± 2.48 degrees in the medial compartment and 6.85± 2.24 degrees in lateral compartment. No significant correlation was found between age and gender with posterior tibial slope ( P ≥0.05), but there was significant relationship among PTS with mediolateral width, plateau area and medial plateau. Comparison of different studies revealed that the PTS value in our study is different from other communities, which can be associated with genetic and racial factors. The results of our study are useful to PTS reconstruction in surgeries.

Incidence and epidemiology of tibial shaft fractures.

PubMed

Larsen, Peter; Elsoe, Rasmus; Hansen, Sandra Hope; Graven-Nielsen, Thomas; Laessoe, Uffe; Rasmussen, Sten

2015-04-01

The literature lacks recent population-based epidemiology studies of the incidence, trauma mechanism and fracture classification of tibial shaft fractures. The purpose of this study was to provide up-to-date information on the incidence of tibial shaft fractures in a large and complete population and report the distribution of fracture classification, trauma mechanism and patient baseline demographics. Retrospective reviews of clinical and radiological records. A total of 196 patients were treated for 198 tibial shaft fractures in the years 2009 and 2010. The mean age at time of fracture was 38.5 (21.2SD) years. The incidence of tibial shaft fracture was 16.9/100,000/year. Males have the highest incidence of 21.5/100,000/year and present with the highest frequency between the age of 10 and 20, whereas women have a frequency of 12.3/100,000/year and have the highest frequency between the age of 30 and 40. AO-type 42-A1 was the most common fracture type, representing 34% of all tibial shaft fractures. The majority of tibial shaft fractures occur during walking, indoor activity and sports. The distribution among genders shows that males present a higher frequency of fractures while participating in sports activities and walking. Women present the highest frequency of fractures while walking and during indoor activities. This study shows an incidence of 16.9/100,000/year for tibial shaft fractures. AO-type 42-A1 was the most common fracture type, representing 34% of all tibial shaft fractures. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Tibial periostitis ("medial tibial stress syndrome")].

PubMed

Fournier, Pierre-Etienne

2003-06-01

Medial tibial stress syndrome is characterised by complaints along the posteromedial tibia. Runners and athletes involved in jumping activities may develop this syndrome. Increased stress to stabilize the foot especially when excessive pronation is present explain the occurrence this lesion.

Posterior Tibial Slope Angle Correlates With Peak Sagittal and Frontal Plane Knee Joint Loading During Robotic Simulations of Athletic Tasks.

PubMed

Bates, Nathaniel A; Nesbitt, Rebecca J; Shearn, Jason T; Myer, Gregory D; Hewett, Timothy E

2016-07-01

Tibial slope angle is a nonmodifiable risk factor for anterior cruciate ligament (ACL) injury. However, the mechanical role of varying tibial slopes during athletic tasks has yet to be clinically quantified. To examine the influence of posterior tibial slope on knee joint loading during controlled, in vitro simulation of the knee joint articulations during athletic tasks. Descriptive laboratory study. A 6 degree of freedom robotic manipulator positionally maneuvered cadaveric knee joints from 12 unique specimens with varying tibial slopes (range, -7.7° to 7.7°) through drop vertical jump and sidestep cutting tasks that were derived from 3-dimensional in vivo motion recordings. Internal knee joint torques and forces were recorded throughout simulation and were linearly correlated with tibial slope. The mean (±SD) posterior tibial slope angle was 2.2° ± 4.3° in the lateral compartment and 2.3° ± 3.3° in the medial compartment. For simulated drop vertical jumps, lateral compartment tibial slope angle expressed moderate, direct correlations with peak internally generated knee adduction (r = 0.60-0.65), flexion (r = 0.64-0.66), lateral (r = 0.57-0.69), and external rotation torques (r = 0.47-0.72) as well as inverse correlations with peak abduction (r = -0.42 to -0.61) and internal rotation torques (r = -0.39 to -0.79). Only frontal plane torques were correlated during sidestep cutting simulations. For simulated drop vertical jumps, medial compartment tibial slope angle expressed moderate, direct correlations with peak internally generated knee flexion torque (r = 0.64-0.69) and lateral knee force (r = 0.55-0.74) as well as inverse correlations with peak external torque (r = -0.34 to -0.67) and medial knee force (r = -0.58 to -0.59). These moderate correlations were also present during simulated sidestep cutting. The investigation supported the theory that increased posterior tibial slope would lead to greater magnitude knee joint moments, specifically, internally generated knee adduction and flexion torques. The knee torques that positively correlated with increased tibial slope angle in this investigation are associated with heightened risk of ACL injury. Therefore, the present data indicated that a higher posterior tibial slope is correlated to increased knee loads that are associated with heightened risk of ACL injury. © 2016 The Author(s).

Effect of ACL Transection on Internal Tibial Rotation in an in Vitro Simulated Pivot Landing

PubMed Central

Oh, Youkeun K.; Kreinbrink, Jennifer L.; Ashton-Miller, James A.; Wojtys, Edward M.

2011-01-01

Background: The amount of resistance provided by the ACL (anterior cruciate ligament) to axial tibial rotation remains controversial. The goal of this study was to test the primary hypotheses that ACL transection would not significantly affect tibial rotation under the large impulsive loads associated with a simulated pivot landing but would increase anterior tibial translation. Methods: Twelve cadaveric knees (mean age of donors [and standard deviation] at the time of death, 65.0 ± 10.5 years) were mounted in a custom testing apparatus to simulate a single-leg pivot landing. A compound impulsive load was applied to the distal part of the tibia with compression (∼800 N), flexion moment (∼40 N-m), and axial tibial torque (∼17 N-m) in the presence of five trans-knee muscle forces. A differential variable reluctance transducer mounted on the anteromedial aspect of the ACL measured relative strain. With the knee initially in 15° of flexion, and after five combined compression and flexion moment (baseline) loading trials, six trials were conducted with the addition of either internal or external tibial torque (internal or external loading), and then six baseline trials were performed. The ACL was then sectioned, six baseline trials were repeated, and then six trials of either the internal or the external loading condition, whichever had initially resulted in the larger relative ACL strain, were carried out. Tibiofemoral kinematics were measured optoelectronically. The results were analyzed with a nonparametric Wilcoxon signed-rank test. Results: Following ACL transection, the increase in the normalized internal tibial rotation was significant but small (0.7°/N-m ± 0.3°/N-m to 0.8°/N-m ± 0.3°/N-m, p = 0.012), while anterior tibial translation increased significantly (3.8 ± 2.9 to 7.0 ± 2.9 mm, p = 0.017). Conclusions: ACL transection leads to a small increase in internal tibial rotation, equivalent to a 13% decrease in the dynamic rotational resistance, under the large forces associated with a simulated pivot landing, but it leads to a significant increase in anterior tibial translation. Clinical Relevance: An ACL reconstruction that restores both ligament orientation and stiffness will provide major resistance to anterior tibial translation while providing minor resistance to axial tibial rotation. PMID:21325589

Peripheral Vasculature: High-Temporal- and High-Spatial-Resolution Three-dimensional Contrast-enhanced MR Angiography1

PubMed Central

Haider, Clifton R.; Glockner, James F.; Stanson, Anthony W.; Riederer, Stephen J.

2009-01-01

Purpose: To prospectively evaluate the feasibility of performing high-spatial-resolution (1-mm isotropic) time-resolved three-dimensional (3D) contrast material–enhanced magnetic resonance (MR) angiography of the peripheral vasculature with Cartesian acquisition with projection-reconstruction–like sampling (CAPR) and eightfold accelerated two-dimensional (2D) sensitivity encoding (SENSE). Materials and Methods: All studies were approved by the institutional review board and were HIPAA compliant; written informed consent was obtained from all participants. There were 13 volunteers (mean age, 41.9; range, 27–53 years). The CAPR sequence was adapted to provide 1-mm isotropic spatial resolution and a 5-second frame time. Use of different receiver coil element sizes for those placed on the anterior-to-posterior versus left-to-right sides of the field of view reduced signal-to-noise ratio loss due to acceleration. Results from eight volunteers were rated independently by two radiologists according to prominence of artifact, arterial to venous separation, vessel sharpness, continuity of arterial signal intensity in major arteries (anterior and posterior tibial, peroneal), demarcation of origin of major arteries, and overall diagnostic image quality. MR angiographic results in two patients with peripheral vascular disease were compared with their results at computed tomographic angiography. Results: The sequence exhibited no image artifact adversely affecting diagnostic image quality. Temporal resolution was evaluated to be sufficient in all cases, even with known rapid arterial to venous transit. The vessels were graded to have excellent sharpness, continuity, and demarcation of the origins of the major arteries. Distal muscular branches and the communicating and perforating arteries were routinely seen. Excellent diagnostic quality rating was given for 15 (94%) of 16 evaluations. Conclusion: The feasibility of performing high-diagnostic-quality time-resolved 3D contrast-enhanced MR angiography of the peripheral vasculature by using CAPR and eightfold accelerated 2D SENSE has been demonstrated. © RSNA, 2009 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.2533081744/-/DC1 PMID:19789238

Modeling knee joint endoprosthesis mode of deformation

NASA Astrophysics Data System (ADS)

Skeeba, V. Yu; Ivancivsky, V. V.

2018-03-01

The purpose of the work was to define the efficient design of the endoprosthesis, working in a multiple-cycle loading environment. Methodology and methods: triangulated surfaces of the base contact surfaces of endoprosthesis butt elements have been created using the PowerShape and SolidWorks software functional environment, and the assemblies of the possible combinations of the knee joint prosthetic designs have been prepared. The mode of deformation modeling took place in the multipurpose program complex ANSYS. Results and discussion: as a result of the numerical modeling, the following data were obtained for each of the developed knee joint versions: the distribution fields of absolute (total) and relative deformations; equivalent stress distribution fields; fatigue strength coefficient distribution fields. In the course of the studies, the following efficient design assembly has been established: 1) Ti-Al-V alloy composite femoral component with polymer inserts; 2) ceramic liners of the compound separator; 3) a Ti-Al-V alloy composite tibial component. The fatigue strength coefficient for the femoral component is 4.2; for the femoral component polymer inserts is 1.2; for the ceramic liners of the compound separator is 3.1; for the tibial component is 2.7. This promising endoprosthesis structure is recommended for further design and technological development.

Cranial tibial thrust: a primary force in the canine stifle.

PubMed

Slocum, B; Devine, T

1983-08-15

A cranially directed force identified within the canine stifle joint was termed cranial tibial thrust. It was generated during weight bearing by tibial compression, of which the tarsal tendon of the biceps femoris is a major contributor, and by the slope of the tibial plateau, found to have a mean cranially directed inclination of 22.6 degrees. This force may be an important factor in cranial cruciate ligament rupture and in generation of cranial drawer sign.

Immediate effects of modified landing pattern on a probabilistic tibial stress fracture model in runners.

PubMed

Chen, T L; An, W W; Chan, Z Y S; Au, I P H; Zhang, Z H; Cheung, R T H

2016-03-01

Tibial stress fracture is a common injury in runners. This condition has been associated with increased impact loading. Since vertical loading rates are related to the landing pattern, many heelstrike runners attempt to modify their footfalls for a lower risk of tibial stress fracture. Such effect of modified landing pattern remains unknown. This study examined the immediate effects of landing pattern modification on the probability of tibial stress fracture. Fourteen experienced heelstrike runners ran on an instrumented treadmill and they were given augmented feedback for landing pattern switch. We measured their running kinematics and kinetics during different landing patterns. Ankle joint contact force and peak tibial strains were estimated using computational models. We used an established mathematical model to determine the effect of landing pattern on stress fracture probability. Heelstrike runners experienced greater impact loading immediately after landing pattern switch (P<0.004). There was an increase in the longitudinal ankle joint contact force when they landed with forefoot (P=0.003). However, there was no significant difference in both peak tibial strains and the risk of tibial stress fracture in runners with different landing patterns (P>0.986). Immediate transitioning of the landing pattern in heelstrike runners may not offer timely protection against tibial stress fracture, despite a reduction of impact loading. Long-term effects of landing pattern switch remains unknown. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metal-backed versus all-polyethylene tibial components in primary total knee arthroplasty

PubMed Central

2011-01-01

Background and purpose The choice of either all-polyethylene (AP) tibial components or metal-backed (MB) tibial components in total knee arthroplasty (TKA) remains controversial. We therefore performed a meta-analysis and systematic review of randomized controlled trials that have evaluated MB and AP tibial components in primary TKA. Methods The search strategy included a computerized literature search (Medline, EMBASE, Scopus, and the Cochrane Central Register of Controlled Trials) and a manual search of major orthopedic journals. A meta-analysis and systematic review of randomized or quasi-randomized trials that compared the performance of tibial components in primary TKA was performed using a fixed or random effects model. We assessed the methodological quality of studies using Detsky quality scale. Results 9 randomized controlled trials (RCTs) published between 2000 and 2009 met the inclusion quality standards for the systematic review. The mean standardized Detsky score was 14 (SD 3). We found that the frequency of radiolucent lines in the MB group was significantly higher than that in the AP group. There were no statistically significant differences between the MB and AP tibial components regarding component positioning, knee score, knee range of motion, quality of life, and postoperative complications. Interpretation Based on evidence obtained from this study, the AP tibial component was comparable with or better than the MB tibial component in TKA. However, high-quality RCTs are required to validate the results. PMID:21895503

Survivorship comparison of all-polyethylene and metal-backed tibial components in cruciate-substituting total knee arthroplasty--Chinese experience.

PubMed

Shen, Bin; Yang, Jing; Zhou, Zongke; Kang, Pengde; Wang, Liao; Pei, Fuxing

2009-10-01

Considering its cost saving, the all-polyethylene tibial component is of potential interest in developing countries like China. But to our knowledge, a survivorship comparison of all-polyethylene and metal-backed tibial components in posterior cruciate ligament-substituting total knee arthroplasty (PS-TKA) has not been studied in China previously. Using survivorship analysis, we have studied the midterm outcome of 34 cemented PS-TKA using an all-polyethylene tibial component and of 34 cemented PS-TKA using a metal-backed tibial component which has an identical articular surface with all-polyethylene tibial components. All operations were performed by the same group of surgeons; 58 patients underwent a unilateral operation and five patients a bilateral operation. These patients had a mean follow-up of 5.9 years (range: 5-7 years); three patients were lost to follow-up and one was revised for infection. No significant difference between the two groups was reported regarding HSS scores, ROM, clinical and radiographic parameters measured and survival rates. Although the Asian lifestyle includes more squatting and bending of the knee, the results of this series of TKA using all-polyethylene tibial components in Chinese people are comparable to the satisfactory results of other reported all-polyethylene series whose patients are mainly Western people. Considering its cost saving and excellent clinical result, the all-polyethylene tibial component is of potential interest in developing countries.

Association of physical activity and physical performance with tibial cartilage volume and bone area in young adults.

PubMed

Antony, Benny; Venn, Alison; Cicuttini, Flavia; March, Lyn; Blizzard, Leigh; Dwyer, Terence; Cross, Marita; Jones, Graeme; Ding, Changhai

2015-10-26

Physical activity has been recommended to patients with knee osteoarthritis for improving their symptoms. However, it is still controversial if physical activity has effects on joint structures including cartilage volume. The aim of this study was to describe the associations between physical activity and performance measured 5 years prior and tibial cartilage volume and bone area in young adults. Subjects broadly representative of the Australian population (n = 328, aged 31-41 years, female 47.3 %) were selected from the Childhood Determinants of Adult Health study. They underwent T1-weighted fat-suppressed magnetic resonance imaging (MRI) scans of their knees. Tibial bone area and cartilage volume were measured from MRI. Physical activity (measured using long international physical activity questionnaire (IPAQ)) and performance measures (long jump, leg muscle strength, physical work capacity (PWC170)) were measured 5 years prior. In multivariable analyses, total physical activity (min/week) (β: 0.30 mm(3), 95 % CI: 0.13,0.47), vigorous (β: 0.54 mm(3), 95 % CI: 0.13,0.94), moderate (β: 0.34 mm(3), 95 % CI: 0.01,0.67), walking (β: 0.40 mm(3), 95 % CI: 0.07,0.72) and IPAQ category (β: 182.9 mm(3), 95 % CI: 51.8,314.0) were positively associated with total tibial cartilage volume but not tibial bone area. PWC170, long jump and leg muscle strength were positively and significantly associated with both total tibial cartilage volume and total tibial bone area; and the associations with tibial cartilage volume decreased in magnitude but remained significant for PWC170 and long jump after further adjustment for tibial bone area. While tibial bone area is affected only by physical performance, total tibial cartilage volume can be influenced by both physical activity and performance in younger adults. The clinical significance suggests a beneficial effect for cartilage but the bone area association was restricted to performance suggesting other factors rather than physical activity may be important.

New accelerometric method to discriminate between asymptomatic subjects and patients with medial knee osteoarthritis during 3-d gait.

PubMed

Turcot, Katia; Aissaoui, Rachid; Boivin, Karine; Pelletier, Michel; Hagemeister, Nicola; de Guise, Jacques A

2008-04-01

This study presents a new method to estimate 3-D linear accelerations at tibial and femoral functional coordinate systems. The method combines the use of 3-D accelerometers, 3-D gyroscopes and reflective markers rigidly fixed on an exoskeleton and, a functional postural calibration method. Marker positions were tracked by a six-camera optoelectronic system (VICON 460, Oxford Metrics). The purpose of this study was to determine if this method could discriminate between medial osteoarthritic and asymptomatic knees during gait. Nine patients with osteoarthritic knees and nine asymptomatic control subjects were included in this study. Eighteen parameters representing maximal, minimal, and range of acceleration values were extracted during the loading and preswing to mid-swing phase periods, and were compared in both groups. Results show good discriminative capacity of the new method. Eight parameters were significantly different between both groups. The proposed method has the potential to be used in comprehending and monitoring gait strategy in patients with osteoarthritic knee.

Clinical field follow-up of high density polyethylene (HDPE)-Jaipur prosthetic technology for trans-tibial amputees.

PubMed

Jensen, J S; Craig, J G; Mtalo, L B; Zelaya, C M

2004-12-01

The purpose of this study was to examine the outcome of the application of the High Density Polyethylene (HDPE)-Jaipur prosthetic construction in fitting trans-tibial amputees in a number of projects in the developing world. Projects in Honduras, Uganda and India were visited. Three hundred and twenty (320) patients had been provided with a HDPE-Jaipur prosthesis and of these 172 were seen for a technical and clinical follow-up after a median of 35 months. More than half the amputations were due to trauma, the remainder to disease. Fabrication and fitting in the three projects was carried out by individuals who had undertaken a twice week training course provided by Bhagwan Mahaveer Viklang Sahayata Samiti limb centre in Jaipur. The individuals involved had limited background training in prosthetics. Craftsmanship and fit were assessed as being poor in 56% of cases. The technical quality of the Jaipur foot was considered acceptable as its performance was better than previously observed results. Although there was patient satisfaction of 85% and compliance of 94% the HDPE-Jaipur trans-tibial system was not considered acceptable as 49% reported walking distances less than 1km and 36% discomfort. The major inadequacy in outcome relates to the use for fabrication and fitting of individuals with inadequate education and training.

The anteroposterior axis of the tibia in Korean patients undergoing total knee replacement.

PubMed

Kim, C W; Seo, S S; Kim, J H; Roh, S M; Lee, C R

2014-11-01

The aim of this study was to find anatomical landmarks for rotational alignment of the tibial component in total knee replacement (TKR) in a CT-based study. Pre-operative CT scanning was performed on 94 South Korean patients (nine men, 85 women, 188 knees) with osteoarthritis of the knee joint prior to TKR. The tibial anteroposterior (AP) axis was defined as a line perpendicular to the femoral surgical transepicondylar axis and passing through the centre of the posterior cruciate ligament (PCL). The angles between the defined tibial AP axis and anatomical landmarks at various levels of the tibia were measured. The mean values of the angles between the defined tibial AP axis and the line connecting the anterior border of the proximal third of the tibia to the centre of the PCL was -0.2° (-17 to 14.1, sd 4.1). This was very close to the defined tibial axis, and remained so regardless of lower limb alignment and the degree of tibial bowing. Therefore, AP axis defined as described, is a reliable anatomical landmark for rotational alignment of tibial components. ©2014 The British Editorial Society of Bone & Joint Surgery.

Fine dissection of the tarsal tunnel in 60 cases

PubMed Central

Yang, Y.; Du, M. L.; Fu, Y. S.; Liu, W.; Xu, Q.; Chen, X.; Hao, Y. J.; Liu, Z.; Gao, M. J.

2017-01-01

The fine dissection of nerves and blood vessels in the tarsal tunnel is necessary for clinical operations to provide anatomical information. A total of 60 feet from 30 cadavers were dissected. Two imaginary reference lines that passed through the tip of the medial malleolus were applied. A detailed description of the branch pattern and the corresponding position of the posterior tibial nerve, posterior tibial artery, medial calcaneal nerve and medial calcaneal artery was provided, and the measured data were analyzed. Our results can be summarized as follows. I. A total of 81.67% of the bifurcation points of the posterior tibial nerve, which was divided into the medial and lateral plantar nerves, were located within the tarsal tunnel, not distal to the tarsal tunnel. II. The bifurcation points of the posterior tibial artery were all located in the tarsal tunnel. Almost all of the bifurcation points of the posterior tibial artery were lower than those of the posterior tibial nerve. The bifurcation point of the posterior tibial artery situated distal to the tarsal tunnel was not found. III. The number and the origin of the medial calcaneal nerves and arteries were highly variable. PMID:28398291

Gender differences in passive knee biomechanical properties in tibial rotation.

PubMed

Park, Hyung-Soon; Wilson, Nicole A; Zhang, Li-Qun

2008-07-01

The anterior cruciate ligament (ACL) is the most commonly injured knee ligament with the highest incidence of injury in female athletes who participate in pivoting sports. Noncontact ACL injuries commonly occur with both internal and external tibial rotation. ACL impingement against the lateral wall of the intercondylar notch during tibial external rotation and abduction has been proposed as an injury mechanism, but few studies have evaluated in vivo gender-specific differences in laxity and stiffness in external and internal tibial rotations. The purpose of this study was to evaluate these differences. The knees of 10 male and 10 female healthy subjects were rotated between internal and external tibial rotation with the knee at 60 degrees of flexion. Joint laxity, stiffness, and energy loss were compared between male and female subjects. Women had higher laxity (p = 0.01), lower stiffness (p = 0.038), and higher energy loss (p = 0.008) in external tibial rotation than did men. The results suggest that women may be at greater risk of ACL injury resulting from impingement against the lateral wall of the intercondylar notch, which has been shown to be associated with external tibial rotation and abduction.

Dynamic RSA for the evaluation of inducible micromotion of Oxford UKA during step-up and step-down motion.

PubMed

Horsager, Kristian; Kaptein, Bart L; Rømer, Lone; Jørgensen, Peter B; Stilling, Maiken

2017-06-01

Background and purpose - Implant inducible micromotions have been suggested to reflect the quality of the fixation interface. We investigated the usability of dynamic RSA for evaluation of inducible micromotions of the Oxford Unicompartmental Knee Arthroplasty (UKA) tibial component, and evaluated factors that have been suggested to compromise the fixation, such as fixation method, component alignment, and radiolucent lines (RLLs). Patients and methods - 15 patients (12 men) with a mean age of 69 (55-86) years, with an Oxford UKA (7 cemented), were studied after a mean time in situ of 4.4 (3.6-5.1) years. 4 had tibial RLLs. Each patient was recorded with dynamic RSA (10 frames/second) during a step-up/step-down motion. Inducible micromotions were calculated for the tibial component with respect to the tibia bone. Postoperative component alignment was measured with model-based RSA and RLLs were measured on screened radiographs. Results - All tibial components showed inducible micromotions as a function of the step-cycle motion with a mean subsidence of up to -0.06 mm (95% CI: -0.10 to -0.03). Tibial component inducible micromotions were similar for cemented fixation and cementless fixation. Patients with tibial RLLs had 0.5° (95% CI: 0.18-0.81) greater inducible medio-lateral tilt of the tibial component. There was a correlation between postoperative posterior slope of the tibial plateau and inducible anterior-posterior tilt. Interpretation - All patients had inducible micromotions of the tibial component during step-cycle motion. RLLs and a high posterior slope increased the magnitude of inducible micromotions. This suggests that dynamic RSA is a valuable clinical tool for the evaluation of functional implant fixation.

All-Polyethylene Tibial Components: An Analysis of Long-Term Outcomes and Infection.

PubMed

Houdek, Matthew T; Wagner, Eric R; Wyles, Cody C; Watts, Chad D; Cass, Joseph R; Trousdale, Robert T

2016-07-01

There is debate regarding tibial component modularity and composition in total knee arthroplasty (TKA). Biomechanical studies have suggested improved stress distribution in metal-backed tibias; however, these results have not translated clinically. The purpose of this study was to analyze the outcomes of all-polyethylene components and to compare the results to those with metal-backed components. We reviewed 31,939 patients undergoing a primary TKA over a 43-year period (1970-2013). There were 28,224 (88%) metal-backed and 3715 (12%) all-polyethylene tibial components. The metal-backed and all-polyethylene groups had comparable demographics with respect to gender, age and body mass index (BMI). Mean follow-up was 7 years. The mean survival for all primary TKAs at the 5-, 10-, 20- and 30-year time points was 95%, 89%, 73%, and 57%, respectively. All-polyethylene tibial components were found to have a significantly improved (P < .0001) survivorship when compared with their metal-backed counterparts. All-polyethylene tibial components were also found to have a significantly lower rate of infection, instability, tibial component loosening, and periprosthetic fracture. The all-polyethylene group had improved survival rates in all age groups, except in patients 85 years old or greater, where there was no significant difference. All-polyethylene tibial components had improved survival for all BMI groups except in the morbidly obese (BMI ≥ 40) where there was no significant difference. All-polyethylene tibial components had significantly improved implant survival, reduced rates of postoperative infection, fracture, and tibial component loosening. All polyethylene should be considered for most of the patients, regardless of age and BMI. Copyright © 2016 Elsevier Inc. All rights reserved.

Ground reaction forces and bone parameters in females with tibial stress fracture.

PubMed

Bennell, Kim; Crossley, Kay; Jayarajan, Jyotsna; Walton, Elizabeth; Warden, Stuart; Kiss, Z Stephen; Wrigley, Tim

2004-03-01

Tibial stress fracture is a common overuse running injury that results from the interplay of repetitive mechanical loading and bone strength. This research project aimed to determine whether female runners with a history of tibial stress fracture (TSF) differ in ground reaction force (GRF) parameters during running, regional bone density, and tibial bone geometry from those who have never sustained a stress fracture (NSF). Thirty-six female running athletes (13 TSF; 23 NSF) ranging in age from 18 to 44 yr were recruited for this cross-sectional study. The groups were well matched for demographic, training, and menstrual parameters. A force platform measured selected GRF parameters (peak and time to peak for vertical impact and active forces, and horizontal braking and propulsive forces) during overground running at 4.0 m.s.(-1). Lumbar spine, proximal femur, and distal tibial bone mineral density were assessed by dual energy x-ray absorptiometry. Tibial bone geometry (cross-sectional dimensions and areas, and second moments of area) was calculated from a computerized tomography scan at the junction of the middle and distal thirds. There were no significant differences between the groups for any of the GRF, bone density, or tibial bone geometric parameters (P > 0.05). Both TSF and NSF subjects had bone density levels that were average or above average compared with a young adult reference range. Factor analysis followed by discriminant function analysis did not find any combinations of variables that differentiated between TSF and NSF groups. These findings do not support a role for GRF, bone density, or tibial bone geometry in the development of tibial stress fractures, suggesting that other risk factors were more important in this cohort of female runners.

Fractures of the Tibial Plateau Involve Similar Energies as the Tibial Pilon but Greater Articular Surface Involvement

PubMed Central

Dibbern, Kevin; Kempton, Laurence B.; Higgins, Thomas F.; Morshed, Saam; McKinley, Todd O.; Marsh, J. Lawrence; Anderson, Donald D.

2016-01-01

Patients with tibial pilon fractures have a higher incidence of post-traumatic osteoarthritis than those with fractures of the tibial plateau. This may indicate that pilon fractures present a greater mechanical insult to the joint than do plateau fractures. We tested the hypothesis that fracture energy and articular fracture edge length, two independent indicators of severity, are higher in pilon than plateau fractures. We also evaluated if clinical fracture classification systems accurately reflect severity. Seventy-five tibial plateau fractures and fifty-two tibial pilon fractures from a multi-institutional study were selected to span the spectrum of severity. Fracture severity measures were calculated using objective CT-based image analysis methods. The ranges of fracture energies measured for tibial plateau and pilon fractures were 3.2 to 33.2 Joules (J) and 3.6 to 32.2 J, respectively, and articular fracture edge lengths were 68.0 to 493.0 mm and 56.1 to 288.6 mm, respectively. There were no differences in the fracture energies between the two fracture types, but plateau fractures had greater articular fracture edge lengths (p<0.001). The clinical fracture classifications generally reflected severity, but there was substantial overlap of fracture severity measures between different classes. Clinical Significance Similar fracture energies with different degrees of articular surface involvement suggest a possible explanation for dissimilar rates of post-traumatic osteoarthritis for fractures of the tibial plateau compared to the tibial pilon. The substantial overlap of severity measures between different fracture classes may well have confounded prior clinical studies relying on fracture classification as a surrogate for severity. PMID:27381653

[Application of tibial mechanical axis locator in tibial extra-articular deformity in total knee arthroplasty].

PubMed

Li, Guoliang; Han, Guangpu; Zhang, Jinxiu; Ma, Shiqiang; Guo, Donghui; Yuan, Fulu; Qi, Bingbing; Shen, Runbin

2013-07-01

To explore the application value of self-made tibial mechanical axis locator in tibial extra-articular deformity in total knee arthroplasty (TKA) for improving the lower extremity force line. Between January and August 2012, 13 cases (21 knees) of osteoarthritis with tibial extra-articular deformity were treated, including 5 males (8 knees) and 8 females (13 knees) with an average age of 66.5 years (range, 58-78 years). The disease duration was 2-5 years (mean, 3.5 years). The knee society score (KSS) was 45.5 +/- 15.5. Extra-articular deformities included 1 case of knee valgus (2 knees) and 12 cases of knee varus (19 knees). Preoperative full-length X-ray films of lower extremities showed 10-21 degrees valgus or varus deformity of tibial extra joint. Self-made tibial mechanical axis locator was used to determine and mark coronal tibial mechanical axis under X-ray before TKA, and then osteotomy was performed with extramedullary positioning device according to the mechanical axis marker.' All incisions healed by first intention, without related complications of infection and joint instability. All patients were followed up 5-12 months (mean, 8.3 months). The X-ray examination showed < 2 degrees knee deviation angle in the others except 1 case of 2.9 degrees knee deviation angle at 3 days after operation, and the accurate rate was 95.2%. No loosening or instability of prosthesis occurred during follow-up. KSS score was 85.5 +/- 15.0 at last follow-up, showing significant difference when compared with preoperative score (t=12.82, P=0.00). The seft-made tibial mechanical axis locator can improve the accurate rate of the lower extremity force line in TKA for tibia extra-articular deformity.

Posterior tibial slope in medial opening-wedge high tibial osteotomy: 2-D versus 3-D navigation.

PubMed

Yim, Ji Hyeon; Seon, Jong Keun; Song, Eun Kyoo

2012-10-01

Although opening-wedge high tibial osteotomy (HTO) is used to correct deformities, it can simultaneously alter tibial slope in the sagittal plane because of the triangular configuration of the proximal tibia, and this undesired change in tibial slope can influence knee kinematics, stability, and joint contact pressure. Therefore, medial opening-wedge HTO is a technically demanding procedure despite the use of 2-dimensional (2-D) navigation. The authors evaluated the posterior tibial slope pre- and postoperatively in patients who underwent navigation-assisted opening-wedge HTO and compared posterior slope changes for 2-D and 3-dimensional (3-D) navigation versions. Patients were randomly divided into 2 groups based on the navigation system used: group A (2-D guidance for coronal alignment; 17 patients) and group B (3-D guidance for coronal and sagittal alignments; 17 patients). Postoperatively, the mechanical axis was corrected to a mean valgus of 2.81° (range, 1°-5.4°) in group A and 3.15° (range, 1.5°-5.6°) in group B. A significant intergroup difference existed for the amount of posterior tibial slope change (Δ slope) pre- and postoperatively (P=.04).Opening-wedge HTO using navigation offers accurate alignment of the lower limb. In particular, the use of 3-D navigation results in significantly less change in the posterior tibial slope postoperatively than does the use of 2-D navigation. Accordingly, the authors recommend the use of 3-D navigation systems because they provide real-time intraoperative information about coronal, sagittal, and transverse axes and guide the maintenance of the native posterior tibial slope. Copyright 2012, SLACK Incorporated.

Radiologic assessment of femoral and tibial tunnel placement based on anatomic landmarks in arthroscopic single bundle anterior cruciate ligament reconstruction

PubMed Central

Nema, Sandeep Kumar; Balaji, Gopisankar; Akkilagunta, Sujiv; Menon, Jagdish; Poduval, Murali; Patro, Dilip

2017-01-01

Background: Accurate tibial and femoral tunnel placement has a significant effect on outcomes after anterior cruciate ligament reconstruction (ACLR). Postoperative radiographs provide a reliable and valid way for the assessment of anatomical tunnel placement after ACLR. The aim of this study was to examine the radiographic location of tibial and femoral tunnels in patients who underwent arthroscopic ACLR using anatomic landmarks. Patients who underwent arthroscopic ACLR from January 2014 to March 2016 were included in this retrospective cohort study. Materials and Methods: 45 patients who underwent arthroscopic ACLR, postoperative radiographs were studied. Femoral and tibial tunnel positions on sagittal and coronal radiographic views, graft impingement, and femoral roof angle were measured. Radiological parameters were summarized as mean ± standard deviation and proportions as applicable. Interobserver agreement was measured using intraclass correlation coefficient. Results: The position of the tibial tunnel was found to be at an average of 35.1% ± 7.4% posterior from the anterior edge of the tibia. The femoral tunnel was found at an average of 30% ± 1% anterior to the posterior femoral cortex along the Blumensaat's line. Radiographic impingement was found in 34% of the patients. The roof angle averaged 34.3° ± 4.3°. The position of the tibial tunnel was found at an average of 44.16% ± 3.98% from the medial edge of the tibial plateau. The coronal tibial tunnel angle averaged 67.5° ± 8.9°. The coronal angle of the femoral tunnel averaged 41.9° ± 8.5°. Conclusions: The femoral and tibial tunnel placements correlated well with anatomic landmarks except for radiographic impingement which was present in 34% of the patients. PMID:28566780

Radiologic assessment of femoral and tibial tunnel placement based on anatomic landmarks in arthroscopic single bundle anterior cruciate ligament reconstruction.

PubMed

Nema, Sandeep Kumar; Balaji, Gopisankar; Akkilagunta, Sujiv; Menon, Jagdish; Poduval, Murali; Patro, Dilip

2017-01-01

Accurate tibial and femoral tunnel placement has a significant effect on outcomes after anterior cruciate ligament reconstruction (ACLR). Postoperative radiographs provide a reliable and valid way for the assessment of anatomical tunnel placement after ACLR. The aim of this study was to examine the radiographic location of tibial and femoral tunnels in patients who underwent arthroscopic ACLR using anatomic landmarks. Patients who underwent arthroscopic ACLR from January 2014 to March 2016 were included in this retrospective cohort study. 45 patients who underwent arthroscopic ACLR, postoperative radiographs were studied. Femoral and tibial tunnel positions on sagittal and coronal radiographic views, graft impingement, and femoral roof angle were measured. Radiological parameters were summarized as mean ± standard deviation and proportions as applicable. Interobserver agreement was measured using intraclass correlation coefficient. The position of the tibial tunnel was found to be at an average of 35.1% ± 7.4% posterior from the anterior edge of the tibia. The femoral tunnel was found at an average of 30% ± 1% anterior to the posterior femoral cortex along the Blumensaat's line. Radiographic impingement was found in 34% of the patients. The roof angle averaged 34.3° ± 4.3°. The position of the tibial tunnel was found at an average of 44.16% ± 3.98% from the medial edge of the tibial plateau. The coronal tibial tunnel angle averaged 67.5° ± 8.9°. The coronal angle of the femoral tunnel averaged 41.9° ± 8.5°. The femoral and tibial tunnel placements correlated well with anatomic landmarks except for radiographic impingement which was present in 34% of the patients.

Proximal tibial fracture following anterior cruciate ligament reconstruction surgery: a biomechanical analysis of the tibial tunnel as a stress riser.

PubMed

Aldebeyan, Wassim; Liddell, Antony; Steffen, Thomas; Beckman, Lorne; Martineau, Paul A

2017-08-01

This is the first biomechanical study to examine the potential stress riser effect of the tibial tunnel or tunnels after ACL reconstruction surgery. In keeping with literature, the primary hypothesis tested in this study was that the tibial tunnel acts as a stress riser for fracture propagation. Secondary hypotheses were that the stress riser effect increases with the size of the tunnel (8 vs. 10 mm), the orientation of the tunnel [standard (STT) vs. modified transtibial (MTT)], and with the number of tunnels (1 vs. 2). Tibial tunnels simulating both single bundle hamstring graft (8 mm) and bone-patellar tendon-bone graft (10 mm) either STT or MTT position, as well as tunnels simulating double bundle (DB) ACL reconstruction (7, 6 mm), were drilled in fourth-generation saw bones. These five experimental groups and a control group consisting of native saw bones without tunnels were loaded to failure on a Materials Testing System to simulate tibial plateau fracture. There were no statistically significant differences in peak load to failure between any of the groups, including the control group. The fracture occurred through the tibial tunnel in 100 % of the MTT tunnels (8 and 10 mm) and 80 % of the DB tunnels specimens; however, the fractures never (0 %) occurred through the tibial tunnel of the standard tunnels (8 or 10 mm) (P = 0.032). In the biomechanical model, the tibial tunnel does not appear to be a stress riser for fracture propagation, despite suggestions to the contrary in the literature. Use of a standard, more vertical tunnel decreases the risk of ACL graft compromise in the event of a fracture. This may help to inform surgical decision making on ACL reconstruction technique.

Open wedge high tibial osteotomy using three-dimensional printed models: Experimental analysis using porcine bone.

PubMed

Kwun, Jun-Dae; Kim, Hee-June; Park, Jaeyoung; Park, Il-Hyung; Kyung, Hee-Soo

2017-01-01

The purpose of this study was to evaluate the usefulness of three-dimensional (3D) printed models for open wedge high tibial osteotomy (HTO) in porcine bone. Computed tomography (CT) images were obtained from 10 porcine knees and 3D imaging was planned using the 3D-Slicer program. The osteotomy line was drawn from the three centimeters below the medial tibial plateau to the proximal end of the fibular head. Then the osteotomy gap was opened until the mechanical axis line was 62.5% from the medial border along the width of the tibial plateau, maintaining the posterior tibial slope angle. The wedge-shaped 3D-printed model was designed with the measured angle and osteotomy section and was produced by the 3D printer. The open wedge HTO surgery was reproduced in porcine bone using the 3D-printed model and the osteotomy site was fixed with a plate. Accuracy of osteotomy and posterior tibial slope was evaluated after the osteotomy. The mean mechanical axis line on the tibial plateau was 61.8±1.5% from the medial tibia. There was no statistically significant difference (P=0.160). The planned and post-osteotomy correction wedge angles were 11.5±3.2° and 11.4±3.3°, and the posterior tibial slope angle was 11.2±2.2° pre-osteotomy and 11.4±2.5° post-osteotomy. There were no significant differences (P=0.854 and P=0.429, respectively). This study showed that good results could be obtained in high tibial osteotomy by using 3D printed models of porcine legs. Copyright © 2016 Elsevier B.V. All rights reserved.

Complex Medial Meniscus Tears Are Associated With a Biconcave Medial Tibial Plateau.

PubMed

Barber, F Alan; Getelman, Mark H; Berry, Kathy L

2017-04-01

To determine whether an association exists between a biconcave medial tibial plateau and complex medial meniscus tears. A consecutive series of stable knees undergoing arthroscopy were evaluated retrospectively with the use of preoperative magnetic resonance imaging (MRI), radiographs, and arthroscopy documented by intraoperative videos. Investigators independently performed blinded reviews of the MRI or videos. Based on the arthroscopy findings, medial tibial plateaus were classified as either biconcave or not biconcave. A transverse coronal plane ridge, separating the front of the tibial plateau from the back near the inner margin of the posterior body of the medial meniscus, was defined as biconcave. The medial plateau slope was calculated with MRI sagittal views. General demographic information, body mass index, and arthroscopically confirmed knee pathology were recorded. A total of 179 consecutive knees were studied from July 2014 through August 2015; 49 (27.2%) biconcave medial tibial plateaus and 130 (72.8%) controls were identified at arthroscopy. Complex medial meniscus tears were found in 103. Patients with a biconcave medial tibial plateau were found to have more complex medial meniscus tears (69.4%) than those without a biconcavity (53.1%) (P = .049) despite having lower body mass index (P = .020). No difference in medial tibial plateau slope was observed for biconcavities involving both cartilage and bone, bone only, or an indeterminate group (P = .47). Biconcave medial tibial plateaus were present in 27.4% of a consecutive series of patients undergoing knee arthroscopy. A biconcave medial tibial plateau was more frequently associated with a complex medial meniscus tear. Level III, case-control study. Copyright © 2016 Arthroscopy Association of North America. All rights reserved.

Bypass grafting to the anterior tibial artery.

PubMed

Armour, R H

1976-01-01

Four patients with severe ischaemia of a leg due to atherosclerotic occlusion of the tibial and peroneal arteries had reversed long saphenous vein grafts to the patent lower part of the anterior tibial artery. Two of these grafts continue to function 19 and 24 months after operation respectively. One graft failed on the fifth postoperative day and another occluded 4 months after operation. The literature on femorotibial grafting has been reviewed. The early failure rate of distal grafting is higher than in the case of femoropopliteal bypass, but a number of otherwise doomed limbs can be salvaged. Contrary to widely held views, grafting to the anterior tibial artery appears to give results comparable to those obtained when the lower anastomosis is made to the posterior tibial artery.

Tibial stress fracture after computer-navigated total knee arthroplasty.

PubMed

Massai, F; Conteduca, F; Vadalà, A; Iorio, R; Basiglini, L; Ferretti, A

2010-06-01

A correct alignment of the tibial and femoral component is one of the most important factors determining favourable long-term results of a total knee arthroplasty (TKA). The accuracy provided by the use of the computer navigation systems has been widely described in the literature so that their use has become increasingly popular in recent years; however, unpredictable complications, such as displaced or stress femoral or tibial fractures, have been reported to occur a few weeks after the operation. We present a case of a stress tibial fracture that occurred after a TKA performed with the use of a computer navigation system. The stress fracture, which eventually healed without further complications, occurred at one of the pinhole sites used for the placement of the tibial trackers.

Effects of tibial slope changes in the stability of fixed bearing medial unicompartmental arthroplasty in anterior cruciate ligament deficient knees.

PubMed

Suero, Eduardo M; Citak, Musa; Cross, Michael B; Bosscher, Marianne R F; Ranawat, Anil S; Pearle, Andrew D

2012-08-01

Patients with anterior cruciate ligament (ACL) deficiency may have increased failure rates with UKA as a result of abnormal contact stresses and altered knee kinematics. Variations in the slope of the tibial component in UKA may alter tibiofemoral translation, and affect outcomes. This cadaveric study evaluated tibiofemoral translation during the Lachman and pivot shift tests after changing the slope of a fixed bearing unicondylar tibial component. Sectioning the ACL increased tibiofemoral translation in both the Lachman and pivot shift tests (P<0.05). Tibial slope leveling (decreasing the posterior slope) of the polyethylene insert in a UKA decreases anteroposterior tibiofemoral translation in the sagittal plane to a magnitude similar to that of the intact knee. With 8° of tibial slope leveling, anterior tibial translation during the Lachman test decreased by approximately 5mm. However, no variation in slope altered the pivot shift kinematics in the ACL deficient knees. Copyright © 2011 Elsevier B.V. All rights reserved.

Tension Band Plating for Chronic Anterior Tibial Stress Fractures in High-Performance Athletes.

PubMed

Zbeda, Robert M; Sculco, Peter K; Urch, Ekaterina Y; Lazaro, Lionel E; Borens, Olivier; Williams, Riley J; Lorich, Dean G; Wellman, David S; Helfet, David L

2015-07-01

Anterior tibial stress fractures are associated with high rates of delayed union and nonunion, which can be particularly devastating to a professional athlete who requires rapid return to competition. Current surgical treatment strategies include intramedullary nailing, which has satisfactory rates of fracture union but an associated risk of anterior knee pain. Anterior tension band plating is a biomechanically sound alternative treatment for these fractures. Tension band plating of chronic anterior tibial stress fractures leads to rapid healing and return to physical activity and avoids the anterior knee pain associated with intramedullary nailing. Case series; Level of evidence, 4. Between 2001 and 2013, there were 13 chronic anterior tibial stress fractures in 12 professional or collegiate athletes who underwent tension band plating after failing nonoperative management. Patient charts were retrospectively reviewed for demographics, injury history, and surgical details. Radiographs were used to assess time to osseous union. Follow-up notes and phone interviews were used to determine follow-up time, return to training time, and whether the patient was able to return to competition. Cases included 13 stress fractures in 12 patients (9 females, 3 males). Five patients were track-and-field athletes, 4 patients played basketball, 2 patients played volleyball, and 1 was a ballet dancer. Five patients were Division I collegiate athletes and 7 were professional or Olympic athletes. Average age at time of surgery was 23.6 years (range, 20-32 years). Osseous union occurred on average at 9.6 weeks (range, 5.3-16.9 weeks) after surgery. Patients returned to training on average at 11.1 weeks (range, 5.7-20 weeks). Ninety-two percent (12/13) eventually returned to preinjury competition levels. Thirty-eight percent (5/13) underwent removal of hardware for plate prominence. There was no incidence of infection or nonunion. Anterior tension band plating for chronic tibial stress fractures provides a reliable alternative to intramedullary nailing with excellent results. Compression plating avoids the anterior knee pain associated with intramedullary nailing but may result in symptomatic hardware requiring subsequent removal. © 2015 The Author(s).

Survivorship comparison of all-polyethylene and metal-backed tibial components in cruciate-substituting total knee arthroplasty—Chinese experience

PubMed Central

Shen, Bin; Yang, Jing; Zhou, Zongke; Kang, Pengde; Wang, Liao

2008-01-01

Considering its cost saving, the all-polyethylene tibial component is of potential interest in developing countries like China. But to our knowledge, a survivorship comparison of all-polyethylene and metal-backed tibial components in posterior cruciate ligament-substituting total knee arthroplasty (PS-TKA) has not been studied in China previously. Using survivorship analysis, we have studied the midterm outcome of 34 cemented PS-TKA using an all-polyethylene tibial component and of 34 cemented PS-TKA using a metal-backed tibial component which has an identical articular surface with all-polyethylene tibial components. All operations were performed by the same group of surgeons; 58 patients underwent a unilateral operation and five patients a bilateral operation. These patients had a mean follow-up of 5.9 years (range: 5–7 years); three patients were lost to follow-up and one was revised for infection. No significant difference between the two groups was reported regarding HSS scores, ROM, clinical and radiographic parameters measured and survival rates. Although the Asian lifestyle includes more squatting and bending of the knee, the results of this series of TKA using all-polyethylene tibial components in Chinese people are comparable to the satisfactory results of other reported all-polyethylene series whose patients are mainly Western people. Considering its cost saving and excellent clinical result, the all-polyethylene tibial component is of potential interest in developing countries. PMID:18688613

Systemic Treatment with Strontium Ranelate Accelerates the Filling of a Bone Defect and Improves the Material Level Properties of the Healing Bone

PubMed Central

Zacchetti, Giovanna; Rizzoli, René

2014-01-01

Rapid bone defect filling with normal bone is a challenge in orthopaedics and dentistry. Strontium ranelate (SrRan) has been shown to in vitro decrease bone resorption and increase bone formation, and represents a potential agent with the capacity to accelerate bone defect filling. In this study, bone tibial defects of 2.5 mm in diameter were created in 6-month-old female rats orally fed SrRan (625 mg/kg/d; 5/7 days) or vehicle for 4, 8, or 12 weeks (10 rats per group per time point) from the time of surgery. Tibias were removed. Micro-architecture was determined by micro-computed tomography (µCT) and material level properties by nanoindentation analysis. µCT analysis showed that SrRan administration significantly improved microarchitecture of trabecular bone growing into the defect after 8 and 12 weeks of treatment compared to vehicle. SrRan treatment also accelerated the growth of cortical bone over the defect, but with different kinetics compared to trabecular bone, as the effects were already significant after 4 weeks. Nanoindentation analysis demonstrated that SrRan treatment significantly increased material level properties of both trabecular bone and cortical bone filling the defect compared to vehicle. SrRan accelerates the filling of bone defect by improving cortical and trabecular bone microarchitecture both quantitatively and qualitatively. PMID:25243150

The effect of proximal tibial slope on dynamic stability testing of the posterior cruciate ligament- and posterolateral corner-deficient knee.

PubMed

Petrigliano, Frank A; Suero, Eduardo M; Voos, James E; Pearle, Andrew D; Allen, Answorth A

2012-06-01

Proximal tibial slope has been shown to influence anteroposterior translation and tibial resting point in the posterior cruciate ligament (PCL)-deficient knee. The effect of proximal tibial slope on rotational stability of the knee is unknown. Change in proximal tibial slope produced via osteotomy can influence both static translation and dynamic rotational kinematics in the PCL/posterolateral corner (PLC)-deficient knee. Controlled laboratory study. Posterior drawer, dial, and mechanized reverse pivot-shift (RPS) tests were performed on hip-to-toe specimens and translation of the lateral and medial compartments measured utilizing navigation (n = 10). The PCL and structures of the PLC were then sectioned. Stability testing was repeated, and compartmental translation was recorded. A proximal tibial osteotomy in the sagittal plane was then performed achieving either +5° or -5° of tibial slope variation, after which stability testing was repeated (n = 10). Analysis was performed using 1-way analysis of variance (ANOVA; α = .05). Combined sectioning of the PCL and PLC structures resulted in a 10.5-mm increase in the posterior drawer, 15.5-mm increase in the dial test at 30°, 14.5-mm increase in the dial test at 90°, and 17.9-mm increase in the RPS (vs intact; P < .05). Increasing the posterior slope (high tibial osteotomy [HTO] +5°) in the PCL/PLC-deficient knee reduced medial compartment translation by 3.3 mm during posterior drawer (vs deficient; P < .05) but had no significant effect on the dial test at 30°, dial test at 90°, or RPS. Conversely, reversing the slope (HTO -5°) caused a 4.8-mm increase in medial compartment translation (vs deficient state; P < .05) during posterior drawer and an 8.6-mm increase in lateral compartment translation and 9.0-mm increase in medial compartment translation during RPS (vs deficient state; P < .05). Increasing posterior tibial slope diminished static posterior instability of the PCL/PLC-deficient knee as measured by the posterior drawer test but had little effect on rotational or dynamic multiplanar stability as assessed by the dial and RPS tests, respectively. Conversely, decreasing posterior slope resulted in increased posterior instability and a significant increase in the magnitude of the RPS. These results suggest that increasing posterior tibial slope may improve sagittal stability in the PCL/PLC-deficient knee. Moreover, a knee with diminished posterior tibial slope may demonstrate greater multiplanar instability in this setting. Consequently, proximal tibial slope should be considered when treating combined PCL/PLC injuries of the knee.

Longitudinal tear of the medial meniscus posterior horn in the anterior cruciate ligament-deficient knee significantly influences anterior stability.

PubMed

Ahn, Jin Hwan; Bae, Tae Soo; Kang, Ki-Ser; Kang, Soo Yong; Lee, Sang Hak

2011-10-01

Longitudinal tears of the medial meniscus posterior horn (MMPH) are commonly associated with a chronic anterior cruciate ligament (ACL) deficiency. Many studies have demonstrated the importance of the medial meniscus in terms of limiting the amount of anterior-posterior tibial translation in response to anterior tibial loads in ACL-deficient knees. An MMPH tear in an ACL-deficient knee increases the anterior-posterior tibial translation and rotatory instability. In addition, MMPH repair will restore the tibial translation to the level before the tear. Controlled laboratory study. Ten human cadaveric knees were tested sequentially using a custom testing system under 5 conditions: intact, ACL deficient, ACL deficient with an MMPH peripheral longitudinal tear, ACL deficient with an MMPH repair, and ACL deficient with a total medial meniscectomy. The knee kinematics were measured at 0°, 15°, 30°, 60°, and 90° of flexion in response to a 134-N anterior and 200-N axial compressive tibial load. The rotatory kinematics were also measured at 15° and 30° of flexion in a combined rotatory load of 5 N·m of internal tibial torque and 10 N·m of valgus torque. Medial meniscus posterior horn longitudinal tears in ACL-deficient knees resulted in a significant increase in anterior-posterior tibial translation at all flexion angles except 90° (P < .05). An MMPH repair in an ACL-deficient knee showed a significant decrease in anterior-posterior tibial translation at all flexion angles except 60° compared with the ACL-deficient/MMPH tear state (P < .05). The total anterior-posterior translation of the ACL-deficient/MMPH repaired knee was not significantly increased compared with the ACL (only)-deficient knee but was increased compared with the ACL-intact knee (P > .05). A total medial meniscectomy in an ACL-deficient knee did not increase the anterior-posterior tibial translation significantly compared with MMPH tears in ACL-deficient knees at all flexion angles (P > .05). In a combined rotatory load, tibial rotation after MMPH tears or a total medial meniscectomy in an ACL-deficient knee were not affected significantly at all flexion angles. This study shows that an MMPH longitudinal tear in an ACL-deficient knee alters the knee kinematics, particularly the anterior-posterior tibial translation. MMPH repair significantly improved anterior-posterior tibial translation in ACL-deficient knees. These findings may help improve the treatment of patients with ACL and MMPH longitudinal tear by suggesting that the medial meniscal repairs should be performed for greater longevity when combined with an ACL reconstruction.

Bilateral double level tibial lengthening in dwarfism.

PubMed

Burghardt, Rolf D; Yoshino, Koichi; Kashiwagi, Naoya; Yoshino, Shigeo; Bhave, Anil; Paley, Dror; Herzenberg, John E

2015-12-01

Outcome assessment after double level tibial lengthening in patients with dwarfism. Fourteen patients with dwarfism were analyzed after bilateral simultaneous double level tibial lengthening. Average age was 15.1 years. Average lengthening was 13.5 cm. The two levels were lengthened by an average of 7.5 cm proximally and 6.0 cm distally. Concomitant deformities were also addressed during lengthening. External fixation treatment time averaged 8.8 months. Healing index averaged 0.7 months/cm. Bilateral tibial lengthening for dwarfism is difficult, but the results are usually quite gratifying.

Understanding the etiology of the posteromedial tibial stress fracture.

PubMed

Milgrom, Charles; Burr, David B; Finestone, Aharon S; Voloshin, Arkady

2015-09-01

Previous human in vivo tibial strain measurements from surface strain gauges during vigorous activities were found to be below the threshold value of repetitive cyclical loading at 2500 microstrain in tension necessary to reduce the fatigue life of bone, based on ex vivo studies. Therefore it has been hypothesized that an intermediate bone remodeling response might play a role in the development of tibial stress fractures. In young adults tibial stress fractures are usually oblique, suggesting that they are the result of failure under shear strain. Strains were measured using surface mounted unstacked 45° rosette strain gauges on the posterior aspect of the flat medial cortex just below the tibial midshaft, in a 48year old male subject while performing vertical jumps, staircase jumps and running up and down stadium stairs. Shear strains approaching 5000 microstrain were recorded during stair jumping and vertical standing jumps. Shear strains above 1250 microstrain were recorded during runs up and down stadium steps. Based on predictions from ex vivo studies, stair and vertical jumping tibial shear strain in the test subject was high enough to potentially produce tibial stress fracture subsequent to repetitive cyclic loading without necessarily requiring an intermediate remodeling response to microdamage. Copyright © 2015 Elsevier Inc. All rights reserved.

Arthroscopic pullout repair of a complete radial tear of the tibial attachment site of the medial meniscus posterior horn.

PubMed

Kim, Young-Mo; Rhee, Kwang-Jin; Lee, June-Kyu; Hwang, Deuk-Soo; Yang, Jun-Young; Kim, Sung-Jae

2006-07-01

We developed an effective arthroscopic pullout technique for repairing complete radial tears of the tibial attachment site of the medial meniscus posterior horn (MMPH). In our technique, the torn meniscus is reattached to the tibial plateau immediately medial or anteromedial to the posterior cruciate ligament (PCL) using two No. 2 Ethibond sutures (Ethicon, Somerville, NJ). After a complete radial tear of the tibial attachment site of the MMPH and its reparability were confirmed, using a Caspari suture loaded with a suture shuttle, one No. 2 Ethibond suture is placed through the meniscus, through the red-red zone, 3 to 5 mm medial to the torn edge of the MMPH, and the other is passed through the meniscocapsular junction 3 to 5 mm medial to the torn edge of the meniscus. Then, a tibial tunnel, 5-mm in diameter, is made from the anteromedial aspect of the proximal tibia to the previously prepared tibial plateau, immediately medial or anteromedial to the PCL, and the two No. 2 Ethibond sutures are pulled out through the tibial tunnel and then fixed to the proximal tibia using a 3.5-mm cortical screw and washer. Firm reattachment of the torn meniscus was confirmed arthroscopically.

The use of a robotic tibial rotation device and an electromagnetic tracking system to accurately reproduce the clinical dial test.

PubMed

Stinton, S K; Siebold, R; Freedberg, H; Jacobs, C; Branch, T P

2016-03-01

The purpose of this study was to: (1) determine whether a robotic tibial rotation device and an electromagnetic tracking system could accurately reproduce the clinical dial test at 30° of knee flexion; (2) compare rotation data captured at the footplates of the robotic device to tibial rotation data measured using an electromagnetic sensor on the proximal tibia. Thirty-two unilateral ACL-reconstructed patients were examined using a robotic tibial rotation device that mimicked the dial test. The data reported in this study is only from the healthy legs of these patients. Torque was applied through footplates and was measured using servomotors. Lower leg motion was measured at the foot using the motors. Tibial motion was also measured through an electromagnetic tracking system and a sensor on the proximal tibia. Load-deformation curves representing rotational motion of the foot and tibia were compared using Pearson's correlation coefficients. Off-axis motions including medial-lateral translation and anterior-posterior translation were also measured using the electromagnetic system. The robotic device and electromagnetic system were able to provide axial rotation data and translational data for the tibia during the dial test. Motion measured at the foot was not correlated to motion of the tibial tubercle in internal rotation or in external rotation. The position of the tibial tubercle was 26.9° ± 11.6° more internally rotated than the foot at torque 0 Nm. Medial-lateral translation and anterior-posterior translation were combined to show the path of the tubercle in the coronal plane during tibial rotation. The information captured during a manual dial test includes both rotation of the tibia and proximal tibia translation. All of this information can be captured using a robotic tibial axial rotation device with an electromagnetic tracking system. The pathway of the tibial tubercle during tibial axial rotation can provide additional information about knee instability without relying on side-to-side comparison between knees. The translation of the proximal tibia is important information that must be considered in addition to axial rotation of the tibia when performing a dial test whether done manually or with a robotic device. Instrumented foot position cannot provide the same information. IV.

In Vivo Tibial Fit and Rotational Analysis of a Customized, Patient-Specific TKA versus Off-the-Shelf TKA.

PubMed

Schroeder, Lennart; Martin, Gregory

2018-05-25

In total knee arthroplasty (TKA), surgeons often face the decision of maximizing tibial component fit and achieving correct rotational alignment at the same time. Customized implants (CIMs) address this difficulty by aiming to replicate the anatomical joint structure, utilizing data from patient-specific knee geometry during the manufacturing. We intraoperatively compared component fit in four tibial zones of a CIM to that of three different off-the-shelf (OTS) TKA designs in 44 knees. Additionally, we assessed the rotational alignment of the tibia using computed tomography (CT)-based computer aided design model analysis. Overall the CIM device showed significantly better component fit than the OTS TKAs. While 18% of OTS designs presented an implant overhang of 3 mm or more, none of the CIM components did ( p  < 0.05). There was a larger percentage of CIMs seen with optimal fit (≤1 mm implant overhang to ≤1 mm tibial bone undercoverage) than in OTS TKAs. Also, OTS implants showed significantly more component underhang of ≥3 mm than the CIM design (37 vs. 18%). The rotational analysis revealed that 45% of the OTS tibial components showed a rotational deviation of more than 5 degrees and 4% of more than 10 degrees to a tibial rotational axis described by Cobb et al. No deviation was seen for the CIM, as the device is designed along this axis. Using the medial one-third of the tibial tubercle as the rotational landmark, 95% of the OTS trays demonstrated a rotational deviation of more than 5 degrees and 73% of more than 10 degrees compared with 73% of CIM tibial trays with more than 5 degrees and 27% with more than 10 degrees. Based on our findings, we believe that the CIM TKA provides both better rotational alignment and tibial fit without causing overhang of the tibial tray than the three examined OTS implants. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

What Strains the Anterior Cruciate Ligament During a Pivot Landing?

PubMed Central

Oh, Youkeun K.; Lipps, David B.; Ashton-Miller, James A.; Wojtys, Edward M.

2015-01-01

Background The relative contributions of an axial tibial torque and frontal plane moment to anterior cruciate ligament (ACL) strain during pivot landings are unknown. Hypothesis The peak normalized relative strain in the anteromedial (AM) bundle of the ACL is affected by the direction of the axial tibial torque but not by the direction of the frontal plane moment applied concurrently during a simulated jump landing. Study Design Controlled and descriptive laboratory studies. Methods Fifteen adult male knees with pretensioned knee muscle-tendon unit forces were loaded under a simulated pivot landing test. Compression, flexion moment, internal or external tibial torque, and knee varus or valgus moment were simultaneously applied to the distal tibia while recording the 3D knee loads and tibiofemoral kinematics. The AM-ACL relative strain was measured using a 3-mm differential variable reluctance transducer. The results were analyzed using nonparametric Wilcoxon signed–rank tests. A 3D dynamic biomechanical knee model was developed using ADAMS and validated to help interpret the experimental results. Results The mean (SD) peak AM-ACL relative strain was 192% greater (P <.001) under the internal tibial torque combined with a knee varus or valgus moment (7.0% [3.9%] and 7.0% [4.1%], respectively) than under external tibial torque with the same moments (2.4% [2.5%] and 2.4% [3.2%], respectively). The knee valgus moment augmented the AM-ACL strain due to the slope of the tibial plateau inducing mechanical coupling (ie, internal tibial rotation and knee valgus moment); this augmentation occurred before medial knee joint space opening. Conclusion An internal tibial torque combined with a knee valgus moment is the worst-case ACL loading condition. However, it is the internal tibial torque that primarily causes large ACL strain. Clinical Relevance Limiting the maximum coefficient of friction between the shoe and playing surface should limit the peak internal tibial torque that can be applied to the knee during jump landings, thereby reducing peak ACL strain and the risk for noncontact injury. PMID:22223717

Area of the tibial insertion site of the anterior cruciate ligament as a predictor for graft size.

PubMed

Guenther, Daniel; Irarrázaval, Sebastian; Albers, Marcio; Vernacchia, Cara; Irrgang, James J; Musahl, Volker; Fu, Freddie H

2017-05-01

To determine the distribution of different sizes of the area of the tibial insertion site among the population and to evaluate whether preoperative MRI measurements correlate with intraoperative findings to enable preoperative planning of the required graft size to cover the tibial insertion site sufficiently. The hypothesis was that the area of the tibial insertion site varies among individuals and that there is good agreement between MRI and intraoperative measurements. Intraoperative measurements of the tibial insertion site were taken on 117 patients. Three measurements were taken in each plane building a grid to cover the tibial insertion site as closely as possible. The mean of the three measurements in each plane was used for determination of the area. Two orthopaedic surgeons, who were blinded to the intraoperative measurements, took magnetic resonance imaging (MRI) measurements of the area of the tibial insertion site at two different time points. The intraoperative measured mean area was 123.8 ± 21.5 mm 2 . The mean area was 132.8 ± 15.7 mm 2 (rater 1) and 136.7 ± 15.4 mm 2 (rater 2) when determined using MRI. The size of the area was approximately normally distributed. Inter-rater (0.89; 95 % CI 0.84, 0.92; p < 0.001) and intrarater reliability (rater 1: 0.97; 95 % CI 0.95, 0.98; p < 0.001; rater 2: 0.95; 95 % CI 0.92, 0.96; p < 0.001) demonstrated excellent test-retest reliability. There was good agreement between MRI and intraoperative measurement of tibial insertion site area (ICCs rater 1: 0.80; 95 % CI 0.71, 0.87; p < 0.001; rater 2: 0.87; 95 % CI 0.81, 0.91; p < 0.001). The tibial insertion site varies in size and shape. Preoperative determination of the area using MRI is repeatable and enables planning of graft choice and size to optimally cover the tibial insertion site. III.

Quadriceps force and anterior tibial force occur obviously later than vertical ground reaction force: a simulation study.

PubMed

Ueno, Ryo; Ishida, Tomoya; Yamanaka, Masanori; Taniguchi, Shohei; Ikuta, Ryohei; Samukawa, Mina; Saito, Hiroshi; Tohyama, Harukazu

2017-11-18

Although it is well known that quadriceps force generates anterior tibial force, it has been unclear whether quadriceps force causes great anterior tibial force during the early phase of a landing task. The purpose of the present study was to examine whether the quadriceps force induced great anterior tibial force during the early phase of a landing task. Fourteen young, healthy, female subjects performed a single-leg landing task. Muscle force and anterior tibial force were estimated from motion capture data and synchronized force data from the force plate. One-way repeated measures analysis of variance and the post hoc Bonferroni test were conducted to compare the peak time of the vertical ground reaction force, quadriceps force and anterior tibial force during the single-leg landing. In addition, we examined the contribution of vertical and posterior ground reaction force, knee flexion angle and moment to peak quadriceps force using multiple linear regression. The peak times of the estimated quadriceps force (96.0 ± 23.0 ms) and anterior tibial force (111.9 ± 18.9 ms) were significantly later than that of the vertical ground reaction force (63.5 ± 6.8 ms) during the single-leg landing. The peak quadriceps force was positively correlated with the peak anterior tibial force (R = 0.953, P < 0.001). Multiple linear regression analysis showed that the peak knee flexion moment contributed significantly to the peak quadriceps force (R 2  = 0.778, P < 0.001). The peak times of the quadriceps force and the anterior tibial force were obviously later than that of the vertical ground reaction force for the female athletes during successful single-leg landings. Studies have reported that the peak time of the vertical ground reaction force was close to the time of anterior cruciate ligament (ACL) disruption in ACL injury cases. It is possible that early contraction of the quadriceps during landing might induce ACL disruption as a result of excessive anterior tibial force in unanticipated situations in ACL injury cases.

Significant RF-EMF and thermal levels observed in a computational model of a person with a tibial plate for grounded 40 MHz exposure.

PubMed

McIntosh, Robert L; Iskra, Steve; Anderson, Vitas

2014-05-01

Using numerical modeling, a worst-case scenario is considered when a person with a metallic implant is exposed to a radiofrequency (RF) electromagnetic field (EMF). An adult male standing on a conductive ground plane was exposed to a 40 MHz vertically polarized plane wave field, close to whole-body resonance where maximal induced current flows are expected in the legs. A metal plate (50-300 mm long) was attached to the tibia in the left leg. The findings from this study re-emphasize the need to ensure compliance with limb current reference levels for exposures near whole-body resonance, and not just rely on compliance with ambient electric (E) and magnetic (H) field reference levels. Moreover, we emphasize this recommendation for someone with a tibial plate, as failure to comply may result in significant tissue damage (increases in the localized temperature of 5-10 °C were suggested by the modeling for an incident E-field of 61.4 V/m root mean square (rms)). It was determined that the occupational reference level for limb current (100 mA rms), as stipulated in the 1998 guidelines of the International Commission on Non-Ionizing Radiation Protection (ICNIRP), is satisfied if the plane wave incident E-field levels are no more than 29.8 V/m rms without an implant and 23.4 V/m rms for the model with a 300 mm implant. © 2014 Wiley Periodicals, Inc.

Surgical treatment of a proximal diaphyseal tibial deformity associated with partial caudal and cranial cruciate ligament deficiency and patella baja.

PubMed

Vincenti, S; Knell, S; Pozzi, A

2017-04-01

Caudal cruciate ligament injury can be a complication following tibial plateau leveling osteotomy (TPLO) (Slocum und Slocum, 1993) especially if the post-operative Tibial Plateau Angle (TPA) is less than 5 degree. We describe a case of negative TPA associated with partial cranial and caudal ligament rupture treated with a center of rotation of angulation (CORA) based cranial tibial opening wedge osteotomy and tibial tuberosity transposition. A 13 kg, mixed breed dog was presented for right pelvic limb lameness. Radiographically a bilateral patella baja and a malformed tibia tuberosity along with a bilateral TPA of -8 degree were detected. Arthroscopically a partial rupture of the cranial and caudal cruciate ligaments were found. A cranial tibial opening wedge osteotomy of 23 degree and a fibular ostectomy were performed. The osteotomy was fixed with a 8 holes ALPS 9 (KYON, Switzerland) and a 3-holes 2.0mm UniLock plate (Synthes, Switzerland). Then a proximal tibial tuberosity transposition of 10mm was performed and fixed with a pin and tension band construct. The postoperative TPA was 15 degree. The radiographic controls at 6, 10 weeks, 6 months and 1 year after surgery revealed an unchanged position of the implants and progressive healing of the osteotomies. At the 6 and 12 months recheck evaluation the dog had no evidence of lameness or stifle pain and radiographs revealed complete healing of the osteotomy site and no implant failure. The diaphyseal CORA based osteotomy allowed accurate correction of a proximal tibial deformity associated with negative TPA.

Effects of diabetic peripheral neuropathy on gait in vascular trans-tibial amputees.

PubMed

Nakajima, Hiroshi; Yamamoto, Sumiko; Katsuhira, Junji

2018-07-01

Patients with diabetes often develop diabetic peripheral neuropathy, which is a distal symmetric polyneuropathy, so foot function on the non-amputated side is expected to affect gait in vascular trans-tibial amputees. However, there is little information on the kinematics and kinetics of gait or the effects of diabetic peripheral neuropathy in vascular trans-tibial amputees. This study aimed to clarify these effects, including the biomechanics of the ankle on the non-amputated side. Participants were 10 vascular trans-tibial amputees with diabetic peripheral neuropathy (group V) and 8 traumatic trans-tibial amputees (group T). Each subject's gait was analyzed at a self-selected speed using a three-dimensional motion analyzer and force plates. Ankle plantarflexion angle, heel elevation angle, and peak and impulse of anterior ground reaction force were smaller on the non-amputated side during pre-swing in group V than in group T. Center of gravity during pre-swing on the non-amputated side was lower in group V than in group T. Hip extension torque during loading response on the prosthetic side was greater in group V than in group T. These findings suggest that the biomechanical function of the ankle on the non-amputated side during pre-swing is poorer in vascular trans-tibial amputees with DPN than in traumatic trans-tibial amputees; the height of the center of gravity could not be maintained during this phase in vascular trans-tibial amputees with diabetic peripheral neuropathy. The hip joint on the prosthetic side compensated for this diminished function at the ankle during loading response. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of open wedge high tibial osteotomy on the lateral tibiofemoral compartment in sheep. Part II: standard and overcorrection do not cause articular cartilage degeneration.

PubMed

Ziegler, Raphaela; Goebel, Lars; Cucchiarini, Magali; Pape, Dietrich; Madry, Henning

2014-07-01

To evaluate whether medial open wedge high tibial osteotomy (HTO) results in structural changes in the articular cartilage in the lateral tibiofemoral compartment of adult sheep. Three experimental groups received biplanar osteotomies of the right proximal tibiae: (a) closing wedge HTO (4.5° of tibial varus), (b) opening wedge HTO (4.5° tibial valgus; standard correction), and (c) opening wedge HTO (9.5° of valgus; overcorrection), each of which was compared to the contralateral knees that only received an arthrotomy. After 6 months, the macroscopic and microscopic characteristics of the articular cartilage of the lateral tibiofemoral compartment were assessed. The articular cartilage in the central region of the lateral tibial plateau in sheep had a higher safranin O staining intensity and was 4.6-fold thicker than in the periphery (covered by the lateral meniscus). No topographical variation in the type-II collagen immunoreactivity was seen. All lateral tibial plateaus showed osteoarthritic changes in regions not covered by the lateral meniscus. No osteoarthritis was seen in the peripheral submeniscal regions of the lateral tibial plateau and the lateral femoral condyle. Opening wedge HTO resulting in both standard and overcorrection was not associated with significant macroscopic and microscopic structural changes between groups in the articular cartilage of the lateral tibial plateau and femoral condyle after 6 months in vivo. Opening wedge HTO resulting in both standard and overcorrection is a safe procedure for the articular cartilage in an intact lateral tibiofemoral compartment of adult sheep at 6 months postoperatively.

The soleal line: a cause of tibial pseudoperiostitis.

PubMed

Levine, A H; Pais, M J; Berinson, H; Amenta, P S

1976-04-01

An unusually prominent soleal line (a normal anatomic variant) may mimic periosteal reaction along the posterior margin of the proximal tibial shaft. This area of pseudoperiostitis is differentiated from hyperostoses arising from the anterior tibial tubercle and the interosseous membrane. It is always associated with normal, undisturbed architecture of the underlying bone.

Can the tibial slope be measured on lateral knee radiographs?

PubMed

Faschingbauer, M; Sgroi, M; Juchems, M; Reichel, H; Kappe, T

2014-12-01

The posterior tibial slope influences both the natural knee stability as well as the stability and kinematics after total knee arthroplasty (TKA). Exact definition of the posterior tibial slope (PTS) requires lateral radiographs of the lower limb. Only lateral knee radiographs are routinely obtained after TKA, however. The purpose of the present study therefore was to analyse the relationship between PTS measurement results on short and expanded lateral knee radiographs. The PTS was measured on 100 consecutive lateral radiographs of the lower limb using the mechanical and three diaphyseal axes with various distances below the tibial plateau. Significant differences between PTS results were found for all three diaphyseal axes, with the smallest differences and the strongest correlation for a diaphyseal axis at 16 and 20 cm below the tibial plateau. Using short distances below the tibial plateau (6 and 10 cm) resulted in an overestimation of the PTS of 3°, on average. The PTS measurements in long lateral knee radiographs are more accurate compared to short radiographs. On short lateral knee radiographs, only a estimation of the PTS can be carried out. Diagnostic study, Level II.

Lower-extremity rotational profile and toe-walking in preschool children with autism spectrum disorder.

PubMed

Arik, Atilla; Aksoy, Cemalettin; Aysev, Ayla; Akçakin, Melda

2018-04-24

The aim of this study was to establish the torsional and toe-walking profiles of children with autism spectrum disorder (ASD), and to analyze the correlations between torsion, toe-walking, autism severity score, and age. In total, 79 consecutive children with autism were examined to determine their hip rotations, thigh-foot angle, degree of toe-walking, and autism severity. Femoral and tibial torsion values, of the preschool patients, were compared statistically with age-matched controls. The hip rotation profile of the patients was similar to the normal group. Nearly a half of the patients with ASD present excessive external tibial torsion. The difference in the tibial torsion between patients and normal children was statistically significant. A weak correlation was found only between tibial torsion and the autism severity score, but no correlation was found between the other parameters. External tibial torsion is the cardinal and persistent orthopedic manifestation among patients with ASD. Toe-walking is the second most common such manifestation and is an independent orthopedic feature in these patients. External tibial torsion may potentially contribute toward the described gait abnormalities in patients with ASD.

Trampoline fracture of the proximal tibial metaphysis in children may not progress into valgus: a report of seven cases and a brief review.

PubMed

Kakel, R

2012-06-01

Fracture of the proximal tibial metaphysis in children is a rare injury but notorious for carrying the risk of subsequent valgus deformity of the tibia. Trampoline-caused fracture of the proximal tibial metaphysis in children may not progress into valgus. We followed up six children who collectively sustained seven fractures of the proximal tibial metaphysis while trampolining with other heavier and/or older children. Initial and follow-up x-rays were reviewed by an orthopaedic surgeons and two radiologists. None of the patients developed valgus deformity with follow-up. Trampoline is associated with a specific type of injury to the proximal tibia when children are trampolining with other heavier children even without falling off the trampoline. This fracture is linear and complete, often non-displaced. Unlike "other" proximal tibial metaphyseal fractures, trampoline-associated proximal tibial metaphysical fracture in children is not associated with a risk of subsequent valgus deformity. Level 4. case series. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

A Novel Method to Assess Wear Rates of Retrieved Tibial Inserts Following in-vivo Use

NASA Astrophysics Data System (ADS)

Paniogue, Tanille J.

Ultra-high molecular weight polyethylene (UHMWPE) on cobalt chrome is the bearing couple of choice for total knee arthroplasty. The number of patients undergoing total knee arthroplasty has been steadily growing and is projected to continue increasing rapidly in the near future. Many of these patients are younger and more active and therefore need a longer lasting device. However, many of these devices fail prematurely and often the primary reason for failure and ultimately revision is due to wear related issues. Therefore, examining how wear rates of the UHMWPE tibial insert change during in-vivo use can help elucidate the mechanisms of accelerated wear and hopefully aid in finding solutions to combat wear related failures. Different crosslinking treatments have been employed by manufacturers to improve wear resistance of the polyethylene. While this has been shown to be an effective way to reduce wear, crosslinking has led to other issues such as oxidative instability and a decline in mechanical properties. The purpose of this body of work is to examine how changes in oxidation, after in-vivo use, affect wear resistance. A novel testing method was developed to test the native articular surface from retrieved tibial inserts in a laboratory Pin-on-Disk (POD) simulator. The method was validated using short-duration implant articular surfaces and non-articular control pins. In the absence of high surface oxidation or severe surface damage, the articular surface pins had comparable steady state wear rates to their bulk counterparts. Tests of devices with longer in-vivo service show chemical changes consistent with a free-radical mediated oxidation mechanism. Tribological assessment of the articular surfaces shows increasing wear rates as a function of oxidation. While this relationship has been hypothesized in the literature, these experiments represent the first physical demonstration of the phenomenon. The wear mechanism is further explored through infrared spectroscopy, assessment of the wear scar, and documentation of evolution of the contact surfaces in the articulation.

Nontraumatic tibial polyethylene insert cone fracture in mobile-bearing posterior-stabilized total knee arthroplasty.

PubMed

Tanikake, Yohei; Hayashi, Koji; Ogawa, Munehiro; Inagaki, Yusuke; Kawate, Kenji; Tomita, Tetsuya; Tanaka, Yasuhito

2016-12-01

A 72-year-old male patient underwent mobile-bearing posterior-stabilized total knee arthroplasty for osteoarthritis. He experienced a nontraumatic polyethylene tibial insert cone fracture 27 months after surgery. Scanning electron microscopy of the fracture surface of the tibial insert cone suggested progress of ductile breaking from the posterior toward the anterior of the cone due to repeated longitudinal bending stress, leading to fatigue breaking at the anterior side of the cone, followed by the tibial insert cone fracture at the anterior side of the cone, resulting in fracture at the base of the cone. This analysis shows the risk of tibial insert cone fracture due to longitudinal stress in mobile-bearing posterior-stabilized total knee arthroplasty in which an insert is designed to highly conform to the femoral component.

Factors affecting the impingement angle of fixed- and mobile-bearing total knee replacements: a laboratory study.

PubMed

Walker, Peter S; Yildirim, Gokce; Sussman-Fort, Jon; Roth, Jonathan; White, Brian; Klein, Gregg R

2007-08-01

Maximum flexion-or impingement angle-is defined as the angle of flexion when the posterior femoral cortex impacts the posterior edge of the tibial insert. We examined the effects of femoral component placement on the femur, the slope angle of the tibial component, the location of the femoral-tibial contact point, and the amount of internal or external rotation. Posterior and proximal femoral placement, a more posterior femoral-tibial contact point, and a more tibial slope all increased maximum flexion, whereas rotation reduced it. A mobile-bearing knee gave results similar to those of the fixed-bearing knee, but there was no loss of flexion in internal or external rotation if the mobile bearing moved with the femur. In the absence of negative factors, a flexion angle of 150 degrees can be reached before impingement.

Study of the anatomy of the tibial nerve and its branches in the distal medial leg.

PubMed

Torres, André Leal Gonçalves; Ferreira, Marcus Castro

2012-01-01

Determine, through dissection in fresh cadavers, the topographic anatomy of the tibial nerve and its branches at the ankle, in relation to the tarsal tunnel. Bilateral dissections were performed on 26 fresh cadavers and the locations of the tibial nerve bifurcation and its branches were measured in millimeters. For the calcaneal branches, the amount and their respective nerves of origin were also analyzed. The tibial nerve bifurcation occurred under the tunnel in 88% of the cases and proximally in 12%. As for the calcaneal branches, the medial presented with one (58%), two (34%) and three (8%) branches, with the most common source occurring in the tibial nerve (90%) and the lower with a single branch per leg and lateral plantar nerve as the most common origin (70%). Level of Evidence, V Expert opinion .

Outcomes of Surgical Treatment for Anterior Tibial Stress Fractures in Athletes: A Systematic Review.

PubMed

Chaudhry, Zaira S; Raikin, Steven M; Harwood, Marc I; Bishop, Meghan E; Ciccotti, Michael G; Hammoud, Sommer

2017-12-01

Although most anterior tibial stress fractures heal with nonoperative treatment, some may require surgical management. To our knowledge, no systematic review has been conducted regarding surgical treatment strategies for the management of chronic anterior tibial stress fractures from which general conclusions can be drawn regarding optimal treatment in high-performance athletes. This systematic review was conducted to evaluate the surgical outcomes of anterior tibial stress fractures in high-performance athletes. Systematic review; Level of evidence, 4. In February 2017, a systematic review of the PubMed, MEDLINE, Cochrane, SPORTDiscus, and CINAHL databases was performed to identify studies that reported surgical outcomes for anterior tibial stress fractures. Articles meeting the inclusion criteria were screened, and reported outcome measures were documented. A total of 12 studies, published between 1984 and 2015, reporting outcomes for the surgical treatment of anterior tibial stress fractures were included in this review. All studies were retrospective case series. Collectively, surgical outcomes for 115 patients (74 males; 41 females) with 123 fractures were evaluated in this review. The overall mean follow-up was 23.3 months. The most common surgical treatment method reported in the literature was compression plating (n = 52) followed by drilling (n = 33). Symptom resolution was achieved in 108 of 123 surgically treated fractures (87.8%). There were 32 reports of complications, resulting in an overall complication rate of 27.8%. Subsequent tibial fractures were reported in 8 patients (7.0%). Moreover, a total of 17 patients (14.8%) underwent a subsequent procedure after their initial surgery. Following surgical treatment for anterior tibial stress fracture, 94.7% of patients were able to return to sports. The available literature indicates that surgical treatment of anterior tibial stress fractures is associated with a high rate of symptom resolution and return to play in athletes, although the high complication rate and potential need for subsequent procedures are important considerations for surgeons and patients.

Management of Gustilo Anderson III B open tibial fractures by primary fascio-septo-cutaneous local flap and primary fixation: The 'fix and shift' technique.

PubMed

Ramasamy, P R

2017-01-01

Open fractures of tibia have posed great difficulty in managing both the soft tissue and the skeletal components of the injured limb. Gustilo Anderson III B open tibial fractures are more difficult to manage than I, II, and III A fractures. Stable skeletal fixation with immediate soft tissue cover has been the key to the successful outcome in treating open tibial fractures, in particular, Gustilo Anderson III B types. If the length of the open wound is larger and if the exposed surface of tibial fracture and tibial shaft is greater, then the management becomes still more difficult. Thirty six Gustilo Anderson III B open tibial fractures managed between June 2002 and December 2013 with "fix and shift" technique were retrospectively reviewed. All the 36 patients managed by this technique had open wounds measuring >5 cm (post debridement). Under fix and shift technique, stable fixation involved primary external fixator application or primary intramedullary nailing of the tibial fracture and immediate soft tissue cover involved septocutaneous shift, i.e., shifting of fasciocutaneous segments based on septocutaneous perforators. Primary fracture union rate was 50% and reoperation rate (bone stimulating procedures) was 50%. Overall fracture union rate was 100%. The rate of malunion was 14% and deep infection was 16%. Failure of septocutaneous shift was 2.7%. There was no incidence of amputation. Management of Gustilo Anderson III B open tibial fractures with "fix and shift" technique has resulted in better outcome in terms of skeletal factors (primary fracture union, overall union, and time for union and malunion) and soft tissue factors (wound healing, flap failure, access to secondary procedures, and esthetic appearance) when compared to standard methods adopted earlier. Hence, "fix and shift" could be recommended as one of the treatment modalities for open III B tibial fractures.

Does lateral versus medial exposure influence total knee tibial component final external rotation? A CT based study.

PubMed

Passeron, D; Gaudot, F; Boisrenoult, P; Fallet, L; Beaufils, P

2009-10-01

A previous study demonstrated that performing a total knee arthroplasty through a lateral approach including anterior tibial tuberosity (ATT) osteotomy (refixed in its original position) presented numerous advantages: correcting the preoperative patella lateral tilt and improving postoperative patella tracking. We hypothesized that these improvements in patella centering were, at least in part, due to an increased external rotation of the tibial component. Postoperative scannographic studies were, therefore, undertaken to measure tibial component rotation and analyze the results according the medial and lateral exposure used. Rotational positioning of the tibial component is influenced by the lateral or medial approach selected at surgery. Forty-five CAT scans, performed according to the protocol criteria of the French Hip and Knee Society (SFHG), were studied 3 months postoperatively: 15 knees operated through the lateral approach and 30 knees operated through a standard medial approach. The total knee utilized in all these cases was a posteriorly stabilized, fixed-bearing, design. We measured first the angle formed between the perpendicular to the transverse axis of the tibial component and the axis joining the ATT to the center of the knee; second we also measured the coronal distance between the center of the component and the anterior tibial tuberosity (ATT). In the group using the medial approach, the lateral position of the ATT was 7 + or - 3mm with a rotation angle of 18 degrees . In the group using the lateral approach these measurements were respectively 1 + or - 4mm and 2 degrees (p<0.0001). External rotation of the tibial component is substantially increased by the lateral approach compared to the medial approach. Better exposure of the lateral tibial plateau is probably responsible of this difference. This increased external rotation improves postoperative patella tracking. Prospective; comparative; non-randomized study; level 3. 2009 Elsevier Masson SAS. All rights reserved.

Location of the tibial tunnel aperture affects extrusion of the lateral meniscus following reconstruction of the anterior cruciate ligament.

PubMed

Kodama, Yuya; Furumatsu, Takayuki; Miyazawa, Shinichi; Fujii, Masataka; Tanaka, Takaaki; Inoue, Hiroto; Ozaki, Toshifumi

2017-08-01

The anterior root of the lateral meniscus provides functional stability to the meniscus. In this study, we evaluated the relationship between the position of the tibial tunnel and extrusion of the lateral meniscus after anterior cruciate ligament reconstruction, where extrusion provides a proxy measure of injury to the anterior root. The relationship between extrusion and tibial tunnel location was retrospectively evaluated from computed tomography and magnetic resonance images of 26 reconstructed knees, contributed by 25 patients aged 17-31 years. A measurement grid was used to localize the position of the tibial tunnel based on anatomical landmarks identified from the three-dimensional reconstruction of axial computed tomography images of the tibial plateaus. The reference point-to-tibial tunnel distance (mm) was defined as the distance from the midpoint of the lateral edge of the grid to the posterolateral aspect of the tunnel aperture. The optimal cutoff of this distance to minimize post-operative extrusion was identified using receiver operating curve analysis. Extrusion of the lateral meniscus was positively correlated to the reference point-to-tibial tunnel distance (r 2  = 0.64; p < 0.001), with a cutoff distance of 5 mm having a sensitivity to extrusion of 83% and specificity of 93%. The mean extrusion for a distance >5 mm was 0.40 ± 0.43 mm, compared to 1.40 ± 0.51 mm for a distance ≤5 mm (p < 0.001). Therefore, a posterolateral location of the tibial tunnel aperture within the footprint of the anterior cruciate ligament decreases the reference point-to-tibial tunnel distance and increases extrusion of the lateral meniscus post-reconstruction. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1625-1633, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

External torsion in a proximal tibia and internal torsion in a distal tibia occur independently in varus osteoarthritic knees compared to healthy knees.

PubMed

Mochizuki, Tomoharu; Tanifuji, Osamu; Koga, Yoshio; Hata, Ryosuke; Mori, Takahiro; Nishino, Katsutoshi; Sato, Takashi; Kobayashi, Koichi; Omori, Go; Sakamoto, Makoto; Tanabe, Yuji; Endo, Naoto

2017-05-01

The relative torsional angle of the distal tibia is dependent on a deformity of the proximal tibia, and it is a commonly used torsional parameter to describe deformities of the tibia; however, this parameter cannot show the location and direction of the torsional deformity in the entire tibia. This study aimed to identify the detailed deformity in the entire tibia via a coordinate system based on the diaphysis of the tibia by comparing varus osteoarthritic knees to healthy knees. In total, 61 limbs in 58 healthy subjects (age: 54 ± 18 years) and 55 limbs in 50 varus osteoarthritis (OA) subjects (age: 72 ± 7 years) were evaluated. The original coordinate system based on anatomic points only from the tibial diaphysis was established. The evaluation parameters were 1) the relative torsion in the distal tibia to the proximal tibia, 2) the proximal tibial torsion relative to the tibial diaphysis, and 3) the distal tibial torsion relative to the tibial diaphysis. The relative torsion in the distal tibia to the proximal tibia showed external torsion in both groups, while the external torsion was lower in the OA group than in the healthy group (p < 0.0001). The proximal tibial torsion relative to the tibial diaphysis had a higher external torsion in the OA group (p = 0.012), and the distal tibial torsion relative to the tibial diaphysis had a higher internal torsion in the OA group (p = 0.004) in comparison to the healthy group. The reverse torsional deformity, showing a higher external torsion in the proximal tibia and a higher internal torsion in the distal tibia, occurred independently in the OA group in comparison to the healthy group. Clinically, this finding may prove to be a pathogenic factor in varus osteoarthritic knees. Level Ⅲ. Copyright © 2017 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

Avulsion of the tibial tuberosity in a litter of greyhound puppies.

PubMed

Skelly, C M; McAllister, H; Donnelly, W J

1997-10-01

Avulsion of the tibial tuberosity was diagnosed in six of seven greyhound littermates aged five and a half months. The puppies showed hindlimb lameness of varying severity. Radiological assessment of affected stifle joints revealed partial or complete avulsion of the tibial tuberosities. In four puppies the lesions were bilateral. Euthanasia of the two most severely affected puppies was performed; the changes observed on histopathological examination of their cranioproximal tibiae suggested that the underlying lesion was that of osteochondrosis. A hereditary predisposition in greyhounds to osteochondrosis of the physis between the apophysis and the cranioproximal tibial diaphysis is postulated.

Medial tibial pain. A prospective study of its cause among military recruits.

PubMed

Milgrom, C; Giladi, M; Stein, M; Kashtan, H; Margulies, J; Chisin, R; Steinberg, R; Swissa, A; Aharonson, Z

1986-12-01

In a prospective study of 295 infantry recruits during 14 weeks of basic training, 41% had medial tibial pain. Routine scintigraphic evaluation in cases of medial tibial bone pain showed that 63% had abnormalities. A stress fracture was found in 46%. Only two patients had periostitis. None had ischemic medial compartment syndrome. Physical examination could not differentiate between cases with medial tibial bone pain secondary to stress fractures and those with scintigraphically normal tibias. When both pain and swelling were localized in the middle one-third of the tibia, the lesion most likely proved to be a stress fracture.

Tibial anatomy in normal small breed dogs including anisometry of various extracapsular stabilizing suture attachment sites.

PubMed

Witte, P G

2015-01-01

To investigate proximal tibial anatomy and its influence on anisometry of extracapsular stabilizing sutures in small dog breeds. Mediolateral radiographs of the femora, stifles, and tibiae of 12 small breed dogs were acquired with the stifles positioned at various angles. Measurements taken included tibial plateau angle (TPA), diaphyseal: proximal tibial angle (DPA), patellar tendon angle (PTA), Z-angle, relative tibial tuberosity width (rTTW), and the distance between six combinations of two femoral and three tibial extra-capsular stabilizing suture (ECS) attachment sites. Theoretical strain through stifle range-of-motion was recorded. The TPA (32° ± 5.8°), DPA (10.2° ± 7.3°), PTA (103.7° ± 6.2°), and Z-angle (70.4° ± 9.0°) were positively correlated with one another (R >0.7), but none were correlated with rTTW (0.93 ± 0.10). The F2-T1 combination of ECS attachment sites had lowest strain for nine stifles. The shortest attachment site separation was at a stifle flexion of 50° for nine stifles. Proximal tibial anatomy measurements could not predict optimal attachment site combination, optimal stifle angle for suture placement, or ECS strain. There is individual variation in the optimal attachment site combination and stifle angle for suture placement, which may influence consistency of outcomes with ECS.

Prediction of Tibial Rotation Pathologies Using Particle Swarm Optimization and K-Means Algorithms.

PubMed

Sari, Murat; Tuna, Can; Akogul, Serkan

2018-03-28

The aim of this article is to investigate pathological subjects from a population through different physical factors. To achieve this, particle swarm optimization (PSO) and K-means (KM) clustering algorithms have been combined (PSO-KM). Datasets provided by the literature were divided into three clusters based on age and weight parameters and each one of right tibial external rotation (RTER), right tibial internal rotation (RTIR), left tibial external rotation (LTER), and left tibial internal rotation (LTIR) values were divided into three types as Type 1, Type 2 and Type 3 (Type 2 is non-pathological (normal) and the other two types are pathological (abnormal)), respectively. The rotation values of every subject in any cluster were noted. Then the algorithm was run and the produced values were also considered. The values of the produced algorithm, the PSO-KM, have been compared with the real values. The hybrid PSO-KM algorithm has been very successful on the optimal clustering of the tibial rotation types through the physical criteria. In this investigation, Type 2 (pathological subjects) is of especially high predictability and the PSO-KM algorithm has been very successful as an operation system for clustering and optimizing the tibial motion data assessments. These research findings are expected to be very useful for health providers, such as physiotherapists, orthopedists, and so on, in which this consequence may help clinicians to appropriately designing proper treatment schedules for patients.

Total knee replacement-cementless tibial fixation with screws: 10-year results.

PubMed

Ersan, Önder; Öztürk, Alper; Çatma, Mehmet Faruk; Ünlü, Serhan; Akdoğan, Mutlu; Ateş, Yalım

2017-12-01

The aim of this study was to evaluate the long term clinical and radiological results of cementless total knee replacement. A total of 51 knees of 49 patients (33 female and 16 male; mean age: 61.6 years (range, 29-66 years)) who underwent TKR surgery with a posterior stabilized hydroxyapatite coated knee implant were included in this study. All of the tibial components were fixed with screws. The HSS scores were examined preoperatively and at the final follow-up. Radiological assessment was performed with Knee Society evaluating and scoring system. Kaplan-Meier survival analysis was performed to rule out the survival of the tibial component. The mean HSS scores were 45.8 (range 38-60) and 88.1 (range 61-93), preoperatively and at the final follow-up respectively. Complete radiological assessment was performed for 48 knees. Lucent lines at the tibial component were observed in 4 patients; one of these patients underwent a revision surgery due to the loosening of the tibial component. The 10-year survival rate of a tibial component was 98%. Cementless total knee replacement has satisfactory long term clinical results. Primary fixation of the tibial component with screws provides adequate stability even in elderly patients with good bone quality. Level IV, Therapeutic study. Copyright © 2017 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

Magnitude of cement-device interfacial stresses with and without tibial stemming: impact of BMI.

PubMed

Gopalakrishnan, Ananthkrishnan; Hedley, Anthony Keith; Kester, Mark A

2011-03-01

Patients expect their total knee arthroplasty to relieve pain and to be long lasting. With patients becoming more active, weighing more, and living longer, this expectation becomes increasingly more difficult to fulfill. Patients who are obese and active put greater loads on their implants and may have a greater risk of failure. Although much attention has been paid to decreasing polyethylene wear, a major cause of implant failure, very little research focus has been directed to elucidate other measures to reduce failure, such as the efficacy of prophylactic stemming of the tibial tray. This study explored whether additional mechanical support for tibial base plates would help reduce bone cement stresses in heavy patients, who, like patients with a high activity level, put added stress on their implants. A tibial base plate with a 12-mm-diameter x 50-mm-long stem was compared with the same tibial base plate with a 15-mm-diameter x 20-mm-long end cap using finite element analysis. The results indicate that the tibial base plate with a prophylactic stem significantly reduced compressive and shear stresses on the cement-device interface and therefore may help to reduce the possibility of tibial loosening in these at-risk patients. Further, such studies will aid the surgeon in educating patients and in selecting the appropriate implant strategy.

Evaluating the suitability of highly cross-linked and remelted materials for use in posterior stabilized knees.

PubMed

Huot, J Caitlin; Van Citters, Douglas W; Currier, John H; Currier, Barbara H; Mayor, Michael B; Collier, John P

2010-11-01

Posterior stabilized (PS) knee designs are a popular choice for cruciate sacrificing knee arthroplasty procedures. The introduction of PS inserts fabricated from highly cross-linked and remelted Ultra High Molecular Weight Polyethylene (UHMWPE) has recently generated concern as these materials have been shown to possess reduced mechanical properties. This study investigated whether highly cross-linked and remelted UHMWPE material (referred to as XRP) can be expected to perform similarly to historical gamma-air polyethylene, which has suffered few reported incidences of tibial post failure. Never-implanted gamma-air PS tibial inserts shelf-aged 14 years were examined and compared to XRP materials. Evaluation of oxidation levels, impact toughness, and fatigue strength demonstrated never-implanted gamma-air PS tibial inserts to possess nonuniform mechanical properties. Despite severe oxidation along the exterior of gamma-air tibial posts, comparatively low oxidation levels at the center of the tibial posts corresponded to sufficiently high mechanical properties. XRP material (75 kGy) showed superior impact toughness over shelf aged gamma-air material; however, tibial post fatigue testing demonstrated XRP material (100 kGy) to be less resistant to fatigue failure than historical gamma-air material. Results from this study indicate that XRP materials (100 kGy) may demonstrate an inferior resistance to tibial post failure than historical polyethylene. © 2010 Wiley Periodicals, Inc.

21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

...-and-socket joint located between a stemmed femoral and a stemmed tibial component and a runner and track joint between each pair of femoral and tibial condyles. The ball-and-socket joint is composed of a...-molybdenum. The ball of the tibial component is held within the socket of the femoral component by the...

21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

...-and-socket joint located between a stemmed femoral and a stemmed tibial component and a runner and track joint between each pair of femoral and tibial condyles. The ball-and-socket joint is composed of a...-molybdenum. The ball of the tibial component is held within the socket of the femoral component by the...

21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

...-and-socket joint located between a stemmed femoral and a stemmed tibial component and a runner and track joint between each pair of femoral and tibial condyles. The ball-and-socket joint is composed of a...-molybdenum. The ball of the tibial component is held within the socket of the femoral component by the...

21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

...-and-socket joint located between a stemmed femoral and a stemmed tibial component and a runner and track joint between each pair of femoral and tibial condyles. The ball-and-socket joint is composed of a...-molybdenum. The ball of the tibial component is held within the socket of the femoral component by the...

Tibial Bowing and Pseudarthrosis in Neurofibromatosis Type 1

DTIC Science & Technology

2014-04-01

Neurofibromatosis Type 1 PRINCIPAL INVESTIGATOR: Dr. David Stevenson CONTRACTING ORGANIZATION: University of Utah SALT LAKE CITY...COVERED 1 April 2013 - 31 March 2014 4. TITLE AND SUBTITLE Tibial Bowing and Pseudarthrosis in Neurofibromatosis Type 1 5a. CONTRACT NUMBER...SUPPLEMENTARY NOTES 14. ABSTRACT Anterolateral tibial bowing is a morbid skeletal manifestation observed in 5% of children with neurofibromatosis

Metachronous Bilateral Posterior Tibial Artery Aneurysms in Ehlers-Danlos Syndrome Type IV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hagspiel, Klaus D., E-mail: kdh2n@virginia.edu; Bonatti, Hugo; Sabri, Saher

2011-04-15

Ehlers-Danlos syndrome type IV is a life-threatening genetic connective tissue disorder. We report a 24-year-old woman with EDS-IV who presented with metachronous bilateral aneurysms/pseudoaneurysms of the posterior tibial arteries 15 months apart. Both were treated successfully with transarterial coil embolization from a distal posterior tibial approach.

Comparison of quantitative evaluation between cutaneous and transosseous inertial sensors in anterior cruciate ligament deficient knee: A cadaveric study.

PubMed

Murase, Atsunori; Nozaki, Masahiro; Kobayashi, Masaaki; Goto, Hideyuki; Yoshida, Masahito; Yasuma, Sanshiro; Takenaga, Tetsuya; Nagaya, Yuko; Mizutani, Jun; Okamoto, Hideki; Iguchi, Hirotaka; Otsuka, Takanobu

2017-09-01

Recently several authors have reported on the quantitative evaluation of the pivot-shift test using cutaneous fixation of inertial sensors. Before utilizing this sensor for clinical studies, it is necessary to evaluate the accuracy of cutaneous sensor in assessing rotational knee instability. To evaluate the accuracy of inertial sensors, we compared cutaneous and transosseous sensors in the quantitative assessment of rotational knee instability in a cadaveric setting, in order to demonstrate their clinical applicability. Eight freshly frozen human cadaveric knees were used in this study. Inertial sensors were fixed on the tibial tuberosity and directly fixed to the distal tibia bone. A single examiner performed the pivot shift test from flexion to extension on the intact knees and ACL deficient knees. The peak overall magnitude of acceleration and the maximum rotational angular velocity in the tibial superoinferior axis was repeatedly measured with the inertial sensor during the pivot shift test. Correlations between cutaneous and transosseous inertial sensors were evaluated, as well as statistical analysis for differences between ACL intact and ACL deficient knees. Acceleration and angular velocity measured with the cutaneous sensor demonstrated a strong positive correlation with the transosseous sensor (r = 0.86 and r = 0.83). Comparison between cutaneous and transosseous sensor indicated significant difference for the peak overall magnitude of acceleration (cutaneous: 10.3 ± 5.2 m/s 2 , transosseous: 14.3 ± 7.6 m/s 2 , P < 0.01) and for the maximum internal rotation angular velocity (cutaneous: 189.5 ± 99.6 deg/s, transosseous: 225.1 ± 103.3 deg/s, P < 0.05), but no significant difference for the maximum external rotation angular velocity (cutaneous: 176.1 ± 87.3 deg/s, transosseous: 195.9 ± 106.2 deg/s, N.S). There is a positive correlation between cutaneous and transosseous inertial sensors. Therefore, this study indicated that the cutaneous inertial sensors could be used clinically for quantifying rotational knee instability, irrespective of the location of utilization. Copyright © 2017 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

Bone microarchitecture of the tibial plateau in skeletal health and osteoporosis.

PubMed

Krause, Matthias; Hubert, Jan; Deymann, Simon; Hapfelmeier, Alexander; Wulff, Birgit; Petersik, Andreas; Püschel, Klaus; Amling, Michael; Hawellek, Thelonius; Frosch, Karl-Heinz

2018-05-07

Impaired bone structure poses a challenge for the treatment of osteoporotic tibial plateau fractures. As knowledge of region-specific structural bone alterations is a prerequisite to achieving successful long-term fixation, the aim of the current study was to characterize tibial plateau bone structure in patients with osteoporosis and the elderly. Histomorphometric parameters were assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT) in 21 proximal tibiae from females with postmenopausal osteoporosis (mean age: 84.3 ± 4.9 years) and eight female healthy controls (45.5 ± 6.9 years). To visualize region-specific structural bony alterations with age, the bone mineral density (Hounsfield units) was additionally analyzed in 168 human proximal tibiae. Statistical analysis was based on evolutionary learning using globally optimal regression trees. Bone structure deterioration of the tibial plateau due to osteoporosis was region-specific. Compared to healthy controls (20.5 ± 4.7%) the greatest decrease in bone volume fraction was found in the medio-medial segments (9.2 ± 3.5%, p < 0.001). The lowest bone volume was found in central segments (tibial spine). Trabecular connectivity was severely reduced. Importantly, in the anterior and posterior 25% of the lateral and medial tibial plateaux, trabecular support and subchondral cortical bone thickness itself were also reduced. Thinning of subchondral cortical bone and marked bone loss in the anterior and posterior 25% of the tibial plateau should require special attention when osteoporotic patients require fracture fixation of the posterior segments. This knowledge may help to improve the long-term, fracture-specific fixation of complex tibial plateau fractures in osteoporosis. Copyright © 2018 Elsevier B.V. All rights reserved.

Flat midsubstance of the anterior cruciate ligament with tibial "C"-shaped insertion site.

PubMed

Siebold, Rainer; Schuhmacher, Peter; Fernandez, Francis; Śmigielski, Robert; Fink, Christian; Brehmer, Axel; Kirsch, Joachim

2015-11-01

This anatomical cadaver study was performed to investigate the flat appearance of the midsubstance shape of the anterior cruciate ligament (ACL) and its tibial "C"-shaped insertion site. The ACL midsubstance and the tibial ACL insertion were dissected in 20 cadaveric knees (n = 6 fresh frozen and n = 14 paraffined). Magnifying spectacles were used for all dissections. Morphometric measurements were performed using callipers and on digital photographs. In all specimens, the midsubstance of the ACL was flat with a mean width of 9.9 mm, thickness of 3.9 mm and cross-sectional area of 38.7 mm(2). The "direct" "C"-shaped tibial insertion runs from along the medial tibial spine to the anterior aspect of the lateral meniscus. The mean width (length) of the "C" was 12.6 mm, its thickness 3.3 mm and area 31.4 mm(2). The centre of the "C" was the bony insertion of the anterior root of the lateral meniscus overlayed by fat and crossed by the ACL. No posterolateral (PL) inserting ACL fibres were found. Together with the larger "indirect" part (area 79.6 mm(2)), the "direct" one formed a "duck-foot"-shaped footprint. The tibial ACL midsubstance and tibial "C"-shaped insertion are flat and are resembling a "ribbon". The centre of the "C" is the bony insertion of the anterior root of the lateral meniscus. There are no central or PL inserting ACL fibres. Anatomical ACL reconstruction may therefore require a flat graft and a "C"-shaped tibial footprint reconstruction with an anteromedial bone tunnel for single bundle and an additional posteromedial bone tunnel for double bundle.

Posterior tibial slope and femoral sizing affect posterior cruciate ligament tension in posterior cruciate-retaining total knee arthroplasty.

PubMed

Kuriyama, Shinichi; Ishikawa, Masahiro; Nakamura, Shinichiro; Furu, Moritoshi; Ito, Hiromu; Matsuda, Shuichi

2015-08-01

During cruciate-retaining total knee arthroplasty, surgeons sometimes encounter increased tension of the posterior cruciate ligament. This study investigated the effects of femoral size, posterior tibial slope, and rotational alignment of the femoral and tibial components on forces at the posterior cruciate ligament in cruciate-retaining total knee arthroplasty using a musculoskeletal computer simulation. Forces at the posterior cruciate ligament were assessed with the standard femoral component, as well as with 2-mm upsizing and 2-mm downsizing in the anterior-posterior dimension. These forces were also determined with posterior tibial slope angles of 5°, 7°, and 9°, and lastly, were measured in 5° increments when the femoral (tibial) components were positioned from 5° (15°) of internal rotation to 5° (15°) of external rotation. Forces at the posterior cruciate ligament increased by up to 718N with the standard procedure during squatting. The 2-mm downsizing of the femoral component decreased the force at the posterior cruciate ligament by up to 47%. The 2° increment in posterior tibial slope decreased the force at the posterior cruciate ligament by up to 41%. In addition, posterior cruciate ligament tension increased by 11% during internal rotation of the femoral component, and increased by 18% during external rotation of the tibial component. These findings suggest that accurate sizing and bone preparation are very important to maintain posterior cruciate ligament forces in cruciate-retaining total knee arthroplasty. Care should also be taken regarding malrotation of the femoral and tibial components because this increases posterior cruciate ligament tension. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of Component Rotation in Total Knee Arthroplasty on Tibiofemoral Kinematics-A Cadaveric Investigation.

PubMed

Maderbacher, Guenther; Keshmiri, Armin; Springorum, Hans R; Maderbacher, Hermann; Grifka, Joachim; Baier, Clemens

2017-09-01

Physiological tibiofemoral kinematics have been shown to be important for good knee function after total knee arthroplasty (TKA). The purpose of the present study was to investigate the influence of component rotation on tibiofemoral kinematics during knee flexion. We asked which axial component alignment best reconstructs physiological tibiofemoral kinematics and which combinations should be avoided. Ten healthy cadaveric knees were examined. By means of a navigational device, tibiofemoral kinematics between 0° and 90° of flexion were assessed before and after TKA using the following different rotational component alignment: femoral components: ligament balanced, 6° internal, 3° external rotation, and 6° external rotation in relation to the posterior condylar line; tibial components: self-adapted, 6° internal rotation, and 6° external rotation. Physiological tibiofemoral kinematics could be partly reconstructed by TKA. Ligament-balanced femoral rotation and 6° femoral external rotation both in combination with 6° tibial component external rotation, and 3° femoral external rotation in combination with 6° tibial component internal rotation or self-aligning tibial component were able to restore tibial longitudinal rotation. Largest kinematical differences were found for the combination femoral component internal and tibial component external rotations. From a kinematic-based view, surgeons should avoid internal rotation of femoral components. However, even often recommended combinations of rotational component alignment (3° femoral external and tibial external rotation) significantly change tibiofemoral kinematics. Self-aligning tibial components solely restored tibiofemoral kinematics with the combination of 3° femoral component of external rotation. For the future, navigational devices might help to axially align components to restore patient-specific and natural tibiofemoral kinematics. Copyright © 2017 Elsevier Inc. All rights reserved.

Risk factors for tibial implant malpositioning in total knee arthrosplasty-consecutive series of one thousand, four hundred and seventeen cases.

PubMed

Gaillard, Romain; Cerciello, Simone; Lustig, Sebastien; Servien, Elvire; Neyret, Philippe

2017-04-01

Total knee arthroplasty (TKA) malalignment may result in pain and limited range of motion. The present study assessed the influence of different surgeon's and patient's related factors on the post-operative tibial tray coronal alignment. The charts and the x-rays of a continuous prospective series of 1417 TKAs operated upon between 1987 and 2015 were retrospectively reviewed. The long-leg AP views were performed at two months post-op and the tibial mechanical angle of the tibial tray was measured. Three groups were defined: varus (≤87° n = 167), valgus (≥93° n = 55) and well alignment (88° to 92° n = 1195). The influence of several pre-operative and peri-operative factors was investigated: surgeon handedness and experience (junior or senior), previous tibial osteotomies, Ahlbäck stage of osteoarthritits, pre-operative alignment, height and weight, age at surgery, approach (medial, lateral or tibial tubercle osteotomy), generation of implants, tray fixation, size of the tray and stem lenght. Univariate then multivariate analysis were performed to find out any correlation. Multivariate analysis showed a strong correlation between varus alignment of the tibial tray and pre-operative varus of the lower limb (p = 0.037), increased BMI (p = 0.016) and operated side opposite to the dominant surgeon's arm (p = 0.006). In a similar way a strong correlation was found between valgus alignment and pre-operative valgus of the limb (p = 0.026). Poor alignment of the tibial tray after TKA was associated with pre-operative malalignment of the lower limb, increased BMI and an index knee which was opposite to surgeon's dominant arm.

The effect of posterior tibial slope on knee flexion in posterior-stabilized total knee arthroplasty.

PubMed

Shi, Xiaojun; Shen, Bin; Kang, Pengde; Yang, Jing; Zhou, Zongke; Pei, Fuxing

2013-12-01

To evaluate and quantify the effect of the tibial slope on the postoperative maximal knee flexion and stability in the posterior-stabilized total knee arthroplasty (TKA). Fifty-six patients (65 knees) who had undergone TKA with the posterior-stabilized prostheses were divided into the following 3 groups according to the measured tibial slopes: Group 1: ≤4°, Group 2: 4°-7° and Group 3: >7°. The preoperative range of the motion, the change in the posterior condylar offset, the elevation of the joint line, the postoperative tibiofemoral angle and the preoperative and postoperative Hospital for Special Surgery (HSS) scores were recorded. The tibial anteroposterior translation was measured using the Kneelax 3 Arthrometer at both the 30° and the 90° flexion angles. The mean values of the postoperative maximal knee flexion were 101° (SD 5), 106° (SD 5) and 113° (SD 9) in Groups 1, 2 and 3, respectively. A significant difference was found in the postoperative maximal flexion between the 3 groups (P < 0.001). However, no significant differences were found between the 3 groups in the postoperative HSS scores, the changes in the posterior condylar offset, the elevation of the joint line or the tibial anteroposterior translation at either the 30° or the 90° flexion angles. A 1° increase in the tibial slope resulted in a 1.8° flexion increment (r = 1.8, R (2) = 0.463, P < 0.001). An increase in the posterior tibial slope can significantly increase the postoperative maximal knee flexion. The tibial slope with an appropriate flexion and extension gap balance during the operation does not affect the joint stability.

Revision 1 size and position of the healthy meniscus, and its correlation with sex, height, weight, and bone area- a cross-sectional study.

PubMed

Bloecker, Katja; Englund, Martin; Wirth, Wolfgang; Hudelmaier, Martin; Burgkart, Rainer; Frobell, Richard B; Eckstein, Felix

2011-10-28

Meniscus extrusion or hypertrophy may occur in knee osteoarthritis (OA). However, currently no data are available on the position and size of the meniscus in asymptomatic men and women with normal meniscus integrity. Three-dimensional coronal DESSwe MRIs were used to segment and quantitatively measure the size and position of the medial and lateral menisci, and their correlation with sex, height, weight, and tibial plateau area. 102 knees (40 male and 62 female) were drawn from the Osteoarthritis Initiative "non-exposed" reference cohort, including subjects without symptoms, radiographic signs, or risk factors for knee OA. Knees with MRI signs of meniscus lesions were excluded. The tibial plateau area was significantly larger (p < 0.001) in male knees than in female ones (+23% medially; +28% laterally), as was total meniscus surface area (p < 0.001, +20% medially; +26% laterally). Ipsi-compartimental tibial plateau area was more strongly correlated with total meniscus surface area in men (r = .72 medially; r = .62 laterally) and women (r = .67; r = .75) than contra-compartimental or total tibial plateau area, body height or weight. The ratio of meniscus versus tibial plateau area was similar between men and women (p = 0.22 medially; p = 0.72 laterally). Tibial coverage by the meniscus was similar between men and women (50% medially; 58% laterally), but "physiological" medial meniscal extrusion was greater in women (1.83 ± 1.06mm) than in men (1.24mm ± 1.18mm; p = 0.011). These data suggest that meniscus surface area strongly scales with (ipsilateral) tibial plateau area across both sexes, and that tibial coverage by the meniscus is similar between men and women.

Revision 1 Size and position of the healthy meniscus, and its Correlation with sex, height, weight, and bone area- a cross-sectional study

PubMed Central

2011-01-01

Background Meniscus extrusion or hypertrophy may occur in knee osteoarthritis (OA). However, currently no data are available on the position and size of the meniscus in asymptomatic men and women with normal meniscus integrity. Methods Three-dimensional coronal DESSwe MRIs were used to segment and quantitatively measure the size and position of the medial and lateral menisci, and their correlation with sex, height, weight, and tibial plateau area. 102 knees (40 male and 62 female) were drawn from the Osteoarthritis Initiative "non-exposed" reference cohort, including subjects without symptoms, radiographic signs, or risk factors for knee OA. Knees with MRI signs of meniscus lesions were excluded. Results The tibial plateau area was significantly larger (p < 0.001) in male knees than in female ones (+23% medially; +28% laterally), as was total meniscus surface area (p < 0.001, +20% medially; +26% laterally). Ipsi-compartimental tibial plateau area was more strongly correlated with total meniscus surface area in men (r = .72 medially; r = .62 laterally) and women (r = .67; r = .75) than contra-compartimental or total tibial plateau area, body height or weight. The ratio of meniscus versus tibial plateau area was similar between men and women (p = 0.22 medially; p = 0.72 laterally). Tibial coverage by the meniscus was similar between men and women (50% medially; 58% laterally), but "physiological" medial meniscal extrusion was greater in women (1.83 ± 1.06mm) than in men (1.24mm ± 1.18mm; p = 0.011). Conclusions These data suggest that meniscus surface area strongly scales with (ipsilateral) tibial plateau area across both sexes, and that tibial coverage by the meniscus is similar between men and women. PMID:22035074

Ketorolac Administered in the Recovery Room for Acute Pain Management Does Not Affect Healing Rates of Femoral and Tibial Fractures.

PubMed

Donohue, David; Sanders, Drew; Serrano-Riera, Rafa; Jordan, Charles; Gaskins, Roger; Sanders, Roy; Sagi, H Claude

2016-09-01

To determine whether ketorolac administered in the immediate perioperative period affects the rate of nonunion in femoral and tibial shaft fractures. Retrospective comparative study. Single Institution, Academic Level 1 Trauma Center. Three hundred and thirteen skeletally mature patients with 137 femoral shaft (OTA 32) and 191 tibial shaft (OTA 42) fractures treated with intramedullary rod fixation. Eighty patients with 33 femoral shaft and 52 tibial shaft fractures were administered ketorolac within the first 24 hours after surgery (group 1-study group). Two-hundred thirty-three patients with 104 femoral shaft and 139 tibial shaft fractures were not (group 2-control group). Rate of reoperation for repair of a nonunion and time to union. Average time to union of the femur was 147 days for group 1 and 159 days for group 2 (P = 0.57). Average time to union of the tibia was 175 days for group 1 and 175 days for group 2 (P = 0.57). There were 3 femoral nonunions (9%) in group 1 and eleven femoral nonunions (11.6%) in group 2 (P = 1.00). There were 3 tibial nonunions (5.8%) in group 1 and 17 tibial nonunions (12.2%) in group 2 (P = 0.29). The average dose of ketorolac for patients who healed their fracture was 85 mg, whereas it was 50 mg for those who did not (P = 0.27). All patients with a nonunion in the study group were current smokers. Ketorolac administered in the first 24 hours after fracture repair for acute pain management does not seem to have a negative impact on time to healing or incidence of nonunion for femoral or tibial shaft fractures. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

EFFECT OF AXIAL TIBIAL TORQUE DIRECTION ON ACL RELATIVE STRAIN AND STRAIN RATE IN AN IN VITRO SIMULATED PIVOT LANDING

PubMed Central

Oh, Youkeun K.; Kreinbrink, Jennifer L.; Wojtys, Edward M.; Ashton-Miller, James A.

2011-01-01

Anterior cruciate ligament (ACL) injuries most frequently occur under the large loads associated with a unipedal jump landing involving a cutting or pivoting maneuver. We tested the hypotheses that internal tibial torque would increase the anteromedial (AM) bundle ACL relative strain and strain rate more than would the corresponding external tibial torque under the large impulsive loads associated with such landing maneuvers. Twelve cadaveric female knees [mean (SD) age: 65.0 (10.5) years] were tested. Pretensioned quadriceps, hamstring and gastrocnemius muscle-tendon unit forces maintained an initial knee flexion angle of 15°. A compound impulsive test load (compression, flexion moment and internal or external tibial torque) was applied to the distal tibia while recording the 3-D knee loads and tibofemoral kinematics. AM-ACL relative strain was measured using a 3mm DVRT. In this repeated measures experiment, the Wilcoxon Signed-Rank test was used to test the null hypotheses with p<0.05 considered significant. The mean (± SD) peak AM-ACL relative strains were 5.4±3.7 % and 3.1±2.8 % under internal and external tibial torque, respectively. The corresponding mean (± SD) peak AM-ACL strain rates reached 254.4±160.1 %/sec and 179.4±109.9 %/sec, respectively. The hypotheses were supported in that the normalized mean peak AM-ACL relative strain and strain rate were 70% and 42% greater under internal than external tibial torque, respectively (p=0.023, p=0.041). We conclude that internal tibial torque is a potent stressor of the ACL because it induces a considerably (70%) larger peak strain in the AM-ACL than does a corresponding external tibial torque. PMID:22025178

Osseointegration properties of titanium dental implants modified with a nanostructured coating based on ordered porous silica and bioactive glass nanoparticles

NASA Astrophysics Data System (ADS)

Covarrubias, Cristian; Mattmann, Matías; Von Marttens, Alfredo; Caviedes, Pablo; Arriagada, Cristián; Valenzuela, Francisco; Rodríguez, Juan Pablo; Corral, Camila

2016-02-01

The fabrication of a nanoporous silica coating loaded with bioactive glass nanoparticles (nBG/NSC) on titanium dental implant surface and its in vitro and in vivo evaluation is presented. The coating was produced by a combined sol-gel and evaporation induced self-assembly process. In vitro bioactivity was assessed in simulated body fluid (SBF) and investigating the osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs). A rat tibial model was employed to analyze the bone response to nBG/NSC-modified titanium implant surface in vivo. The nBG/NSC coating was confirmed at nano level to be constituted by a highly ordered nanoporous silica structure. The coating nanotopography in conjunction with the bioactivity of the BG particles accelerate the in vitro apatite formation and promote the osteogenic differentiation of hBMSCs in absence of osteogenic supplements. These properties accelerate the formation of bone tissue in the periphery of the implant after 3 weeks of implantation. Backscattered scanning electron microscopy images revealed the presence of gaps and soft tissue in the unmodified implant after 6 weeks, whereas the nBG/NSC-modified implant showed mature bone in intimate contact with the implant surface. The nBG/NSC coating appears promising for accelerating the osseointegration of dental implants.

Reconstruction of bilateral tibial aplasia and split hand-foot syndrome in a father and daughter.

PubMed

Al Kaissi, Ali; Ganger, Rudolf; Klaushofer, Klaus; Grill, Franz

2014-01-01

Tibial aplasia is of heterogeneous aetiology, the majority of reports are sporadic. We describe the reconstruction procedures in two subjects - a daughter and father manifested autosomal dominant (AD) inheritance of the bilateral tibial aplasia and split hand-foot syndrome. Reconstruction of these patients required multiple surgical procedures and orthoprosthesis was mandatory. The main goal of treatment was to achieve walking. Stabilization of the ankle joint by fibular-talar-chondrodesis on both sides, followed by bilateral Brown-procedure at the knee joint level has been applied accordingly. The outcome was with improved function of the deformed limbs and walking was achieved with simultaneous designation of orthotic fitting. This is the first study encompassing the diagnosis and management of a father and daughter with bilateral tibial aplasia associated with variable split hand/foot deformity without foot ablation. Our patients showed the typical AD pattern of inheritance of split-hand/foot and tibial aplasia.

Total Knee Arthroplasty for Osteoarthritis Secondary to Fracture of the Tibial Plateau. A Prospective Matched Cohort Study.

PubMed

Lizaur-Utrilla, Alejandro; Collados-Maestre, Isabel; Miralles-Muñoz, Francisco A; Lopez-Prats, Fernando A

2015-08-01

A prospective matched cohort study was performed to compare outcomes of total knee arthroplasties (TKA) between 29 patients with posttraumatic osteoarthritis (POA) after a fracture of tibial plateau and 58 patients underwent routine TKA. Mean follow-up was 6.7 years. There were no significant differences in KSS, WOMAC, SF12 scores or range of motion. In the control group there were no complications. In the posttraumatic group, complications occurred in 4 patients (13.7%) (P=0.010) including partial patellar tendon detachment, superficial infection, skin necrosis, and knee stiffness. Only this last patient required revision for manipulation under anesthesia. Also, there was a revision for tibial aseptic loosening in each group. TKA is an effective treatment for POA after tibial plateau fracture. We recommend the prior removal of hardware, as well as tibial tubercle osteotomy when necessary. Copyright © 2015 Elsevier Inc. All rights reserved.

Management of tibial fractures using a circular external fixator in two calves.

PubMed

Aithal, Hari Prasad; Kinjavdekar, Prakash; Amarpal; Pawde, Abhijit Motiram; Singh, Gaj Raj; Setia, Harish Chandra

2010-07-01

To report the repair of tibial diaphyseal fractures in 2 calves using a circular external skeletal fixator (CEF). Clinical report. Crossbred calves (n=2; age: 6 months; weight: 55 and 60 kg). Mid-diaphyseal tibial fractures were repaired by the use of a 4-ring CEF (made of aluminum rings with 2 mm K-wires) alone in 1 calf and in combination with hemicerclage wiring in 1 calf. Both calves had good weight bearing with moderate lameness postoperatively. Fracture healing occurred by day 60 in 1 calf and by day 30 in calf 2. The CEF was well maintained and tolerated by both calves through fracture healing. Joint mobility and limb usage improved gradually after CEF removal. CEF provided a stable fixation of tibial fractures and healing within 60 days and functional recovery within 90 days. CEF can be safely and successfully used for the management of selected tibial fractures in calves.

[Investigation of tibial bones of the rats exposed on board "Spacelab-2":histomorphometric analysis

NASA Technical Reports Server (NTRS)

Durnova, G. N.; Kaplanskii, A. S.; Morey-Holton, E. R.; Vorobeva, V. N.

1996-01-01

Proximal metaphyses of tibial bones from the Sprague-Dowly rats exposed in US dedicated space life sciences laboratory SLS-2 for 13-14 days and sacrificed on day 13 in microgravity and within 5 hours and 14 days following recovery were the subject of histological, histochemical, and histomorphometric analyses. After the 13-day flight of SLS-2 the rats showed initial signs of osteopenia in the spongy tissue of tibial bones, secondary spongiosis affected first. Resorption of the secondary spongiosis was consequent to enhanced resorption and inhibition of osteogenesis. In rats sacrificed within 5 hours of recovery manifestations of tibial osteopenia were more evident than in rats sacrificed during the flight. Spaceflight-induced changes in tibial spongiosis were reverse by character the amount of spongy bone was fully compensated and following 14 days of readaptation to the terrestrial gravity.

Study of the anatomy of the tibial nerve and its branches in the distal medial leg

PubMed Central

Torres, André Leal Gonçalves; Ferreira, Marcus Castro

2012-01-01

Objective Determine, through dissection in fresh cadavers, the topographic anatomy of the tibial nerve and its branches at the ankle, in relation to the tarsal tunnel. Methods Bilateral dissections were performed on 26 fresh cadavers and the locations of the tibial nerve bifurcation and its branches were measured in millimeters. For the calcaneal branches, the amount and their respective nerves of origin were also analyzed. Results The tibial nerve bifurcation occurred under the tunnel in 88% of the cases and proximally in 12%. As for the calcaneal branches, the medial presented with one (58%), two (34%) and three (8%) branches, with the most common source occurring in the tibial nerve (90%) and the lower with a single branch per leg and lateral plantar nerve as the most common origin (70%). Level of Evidence, V Expert opinion. PMID:24453596

Total knee arthroplasty and fractures of the tibial plateau

PubMed Central

Softness, Kenneth A; Murray, Ryan S; Evans, Brian G

2017-01-01

Tibial plateau fractures are common injuries that occur in a bimodal age distribution. While there are various treatment options for displaced tibial plateau fractures, the standard of care is open reduction and internal fixation (ORIF). In physiologically young patients with higher demand and better bone quality, ORIF is the preferred method of treating these fractures. However, future total knee arthroplasty (TKA) is a consideration in these patients as post-traumatic osteoarthritis is a common long-term complication of tibial plateau fractures. In older, lower demand patients, ORIF is potentially less favorable for a variety of reasons, namely fixation failure and the need for delayed weight bearing. In some of these patients, TKA can be considered as primary mode of treatment. This paper will review the literature surrounding TKA as both primary treatment and as a salvage measure in patients with fractures of the tibial plateau. The outcomes, complications, techniques and surgical challenges are also discussed. PMID:28251061

Assessment of bone healing on tibial fractures treated with wire osteosynthesis associated or not with infrared laser light and biphasic ceramic bone graft (HATCP) and guided bone regeneration (GBR): Raman spectroscopy study

NASA Astrophysics Data System (ADS)

Bastos de Carvalho, Fabíola; Aciole, Gilberth Tadeu S.; Aciole, Jouber Mateus S.; Silveira, Landulfo, Jr.; Nunes dos Santos, Jean; Pinheiro, Antônio L. B.

2011-03-01

The aim of this study was to evaluate, through Raman spectroscopy, the repair of complete tibial fracture in rabbits fixed with wire osteosynthesis - WO, treated or not with infrared laser light (λ 780nm, 50mW, CW) associated or not to the use of HATCP and GBR. Surgical fractures were created under general anesthesia (Ketamine 0.4ml/Kg IP and Xilazine 0.2ml/Kg IP), on the tibia of 15 rabbits that were divided into 5 groups and maintained on individual cages, at day/night cycle, fed with solid laboratory pelted diet and had water ad libidum. On groups II, III, IV and V the fracture was fixed with WO. Animals of groups III and V were grafted with hydroxyapatite + GBR technique. Animals of groups IV and V were irradiated at every other day during two weeks (16J/cm2, 4 x 4J/cm2). Observation time was that of 30 days. After animal death the specimens were kept in liquid nitrogen for further analysis by Raman spectroscopy. Raman spectroscopy showed significant differences between groups (p<0.001). It is concluded that IR laser light was able to accelerate fracture healing and the association with HATCP and GBR resulted on increased deposition of calcium hydroxyapatite.

Tibial plateau fracture after primary anatomic double-bundle anterior cruciate ligament reconstruction: a case report.

PubMed

Gobbi, Alberto; Mahajan, Vivek; Karnatzikos, Georgios

2011-05-01

Tibial plateau fracture after primary anatomic double-bundle anterior cruciate ligament (ACL) reconstruction is rare. To our knowledge, this is the first case report of a tibial plateau fracture after primary anatomic double-bundle ACL reconstruction. In our patient the tibial plateau fracture occurred after a torsional injury to the involved extremity. The fracture occurred 4.5 years after the ACL reconstruction. The fracture was intra-articular Schatzker type IV and had a significant displacement. The patient was treated operatively by open reduction-internal fixation. He recovered well. Copyright © 2011 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Analysis of Arterial Mechanics During Head-Down-Tilt Bed Rest

NASA Technical Reports Server (NTRS)

Elliott, Morgan B.; Martin, David S.; Westby, Christian M.; Stenger, Michael B.; Platts, Steven H.

2014-01-01

Carotid, brachial, and tibial arteries reacted differently to HDTBR. Previous studies have not analyzed the mechanical properties of the human brachial or anterior tibial arteries. After slight variations during bed-rest, arterial mechanical properties and IMT returned to pre-bed rest values, with the exception of tibial stiffness and PSE, which continued to be reduced post-bed rest while the DC remained elevated. The tibial artery remodeling was probably due to decreased pressure and volume. Resulting implications for longer duration spaceflight are unclear. Arterial health may be affected by microgravity, as shown by increased thoracic aorta stiffness in other ground based simulations (Aubert).

Compartment syndrome after tibial plateau fracture☆

PubMed Central

Pitta, Guilherme Benjamin Brandão; dos Santos, Thays Fernanda Avelino; dos Santos, Fernanda Thaysa Avelino; da Costa Filho, Edelson Moreira

2014-01-01

Fractures of the tibial plateau are relatively rare, representing around 1.2% of all fractures. The tibia, due to its subcutaneous location and poor muscle coverage, is exposed and suffers large numbers of traumas, not only fractures, but also crush injuries and severe bruising, among others, which at any given moment, could lead compartment syndrome in the patient. The case is reported of a 58-year-old patient who, following a tibial plateau fracture, presented compartment syndrome of the leg and was submitted to decompressive fasciotomy of the four right compartments. After osteosynthesis with internal fixation of the tibial plateau using an L-plate, the patient again developed compartment syndrome. PMID:26229779

Modified arthroscopic suture fixation of a displaced tibial eminence fracture.

PubMed

Lehman, Ronald A; Murphy, Kevin P; Machen, M Shaun; Kuklo, Timothy R

2003-02-01

This study describes a new arthroscopic method using a whip-stitch technique for treating a displaced type III tibial eminence fracture. A 12-year-old girl who sustained a displaced type III tibial eminence fracture was treated with arthroscopic fixation using the Arthrosew disposable suture device (Surgical Dynamics, Norwalk, CT) to place a whip stitch into the anterior cruciate ligament (ACL). The Arthrex ACL guide (Arthrex, Naples, FL) was used to reduce the avulsed tibial spine fragment. Sutures were then passed through the tibial tunnel and secured over a bony bridge with the knee in 20 degrees of flexion. At 9 months, the patient has a full range of motion with normal Lachman and anterior drawer testing, and she has returned to competitive basketball. Radiographs show complete fracture healing. KT-1000 and isokinetic testing at 9-month follow-up show only minimal side-to-side differences. The Arthrosew device provides a significant advantage in the treatment of type III and IV fractures of the tibial eminence by obtaining arthroscopic fixation within the substance of the ACL, thus obviating arthrotomy and hardware placement. This technique also restores the proper length and tension to the ACL, and provides a simplified, reproducible method of treatment for this injury.

The effect of high tibial osteotomy on osteoarthritis of the knee : Clinical and histological observations.

PubMed

Koshino, T; Tsuchiya, K

1979-03-01

High tibial osteotomies were performed on 136 osteoarthritic knees for correction of varus deformity. Before osteotomy all patients experienced moderate or severe pain, and the knees showed lateral thrust on weight-bearing. The patients were followed up for one to five years. Marked relief of pain was obtained in 112 knees, and the patients were satisfied with the result of operation in 122. These painless knees showed no lateral thrust, and in the majority the deformity had been adequately corrected, with post-operative femoro-tibial angles (standing) ranging from 165° to 174°. Four of 28 knees with femoro-tibial angles of 175° to 179°, when measured one year after operation, showed recurrence of varus deformity three years after osteotomy. Preoperative ranges of knee motion were well maintained after osteotomy even when arthrotomy had also been undertaken. Intra-articular assessment in two patients, several years after operation, showed that the most degenerated portions of the articular surface were completely covered by a fibrocartilagenous layer, with no bare bone.High tibial osteotomy is most effective in osteoarthritic knees with varus deformity, when correction is made to a femoro-tibial angle (standing) of 170° (10° valgus).

The effect of high tibial osteotomy on osteoarthritis of the knee. Clinical and histological observations.

PubMed

Koshino, T; Tsuchiya, K

1979-01-01

High tibial osteotomies were performed on 136 osteoarthritic knees for correction of varus deformity. Before osteotomy all patients experienced moderate or severe pain, and the knees showed lateral thrust on weight-bearing. The patients were followed up for one to five years. Marked relief of pain was obtained in 112 knees, and the patients were satisfied with the result of operation in 122. These painless knees showed no lateral thrust, and in the majority the deformity had been adequately corrected, with post-operative femoro-tibial angles (standing) ranging from 165 degrees to 174 degrees. Four of 28 knees with femoro-tibial angles of 175 degrees to 179 degrees, when measured one year after operation, showed recurrence of varus deformity three years after osteotomy. Preoperative ranges of knee motion were well maintained after osteotomy even when arthrotomy had also been undertaken. Intra-articular assessment in two patients, several years after operation, showed that the most degenerated portions of the articular surface were completely covered by a fibrocartilagenous layer, with no bare bone. High tibial osteotomy is most effective in osteoarthritic knees with varus deformity, when correction is made to a femoro-tibial angle (standing) of 170 degrees (10 degrees valgus).

[Effects of posterior tibial slope on non-contact anterior cruciate ligament rupture and stability of anterior cruciate ligament rupture knee].

PubMed

Yue, De-bo; E, Sen; Wang, Bai-liang; Wang, Wei-guo; Guo, Wan-shou; Zhang, Qi-dong

2013-05-07

To retrospectively explore the correlation between anterior cruciate ligament (ACL)-ruptured knees, stability of ACL-rupture knee and posterior tibial slope (PTS). From January 2008 to October 2012, 150 knees with ACL rupture underwent arthroscopic surgery for ACL reconstruction. A control group was established for subjects undergoing arthroscopic surgery without ACL rupture during the same period. PTS was measured on a digitalized lateral radiograph. Lachman and mechanized pivot shift tests were performed for assessing the stability of knee. There was significant difference (P = 0.007) in PTS angle between the patients with ACL rupture (9.5 ± 2.2 degrees) and the control group (6.6 ± 1.8 degrees). Only among females, increased slope of tibial plateau had effect on the Lachman test. There was a higher positive rate of pivot shift test in patients of increased posterior slope in the ACL rupture group. Increased posterior tibial slope (>6.6) appears to contribute to non-contact ACL injuries in females. And the changes of tibial slope have no effect upon the Lachman test. However, large changes in tibial slope affect pivot shift.

Two-stage Electron Acceleration by 3D Collisionless Guide-field Magnetic Reconnection

NASA Astrophysics Data System (ADS)

Buechner, J.; Munoz, P.

2017-12-01

We discuss a two-stage process of electron acceleration near X-lines of 3D collisionless guide-field magnetic reconnection. Non-relativistic electrons are first pre-accelerated by magnetic-field-aligned (parallel) electric fields. At the nonlinear stage of 3D guide-field magnetic reconnection electric and magnetic fields become filamentary structured due to streaming instabilities. This causes an additional curvature-driven electron acceleration in the guide-field direction. The resulting spectrum of the accelerated electrons follows a power law.

How does tibial cartilage volume relate to symptoms in subjects with knee osteoarthritis?

PubMed Central

Wluka, A; Wolfe, R; Stuckey, S; Cicuttini, F

2004-01-01

Background: No consistent relationship between the severity of symptoms of knee osteoarthritis (OA) and radiographic change has been demonstrated. Objectives: To determine the relationship between symptoms of knee OA and tibial cartilage volume, whether pain predicts loss of cartilage in knee OA, and whether change in cartilage volume over time relates to change in symptoms over the same period. Method: 132 subjects with symptomatic, early (mild to moderate) knee OA were studied. At baseline and 2 years later, participants had MRI scans of their knee and completed questionnaires quantifying symptoms of knee OA (knee-specific WOMAC: pain, stiffness, function) and general physical and mental health (SF-36). Tibial cartilage volume was determined from the MRI images. Results: Complete data were available for 117 (89%) subjects. A weak association was found between tibial cartilage volume and symptoms at baseline. The severity of the symptoms of knee OA at baseline did not predict subsequent tibial cartilage loss. However, weak associations were seen between worsening of symptoms of OA and increased cartilage loss: pain (rs = 0.28, p = 0.002), stiffness (rs = 0.17, p = 0.07), and deterioration in function (rs = 0.21, p = 0.02). Conclusion: Tibial cartilage volume is weakly associated with symptoms in knee OA. There is a weak association between loss of tibial cartilage and worsening of symptoms. This suggests that although cartilage is not a major determinant of symptoms in knee OA, it does relate to symptoms. PMID:14962960

Posterior slope of the tibial implant and the outcome of unicompartmental knee arthroplasty.

PubMed

Hernigou, Philippe; Deschamps, Gerard

2004-03-01

Laboratory studies have suggested that the sagittal displacements permitted by a knee replacement are influenced by the posterior slope of the tibial implant. The effect of the posterior slope of the tibial implant on the outcome of unicompartmental arthroplasty is not well known. The purpose of the present study was to assess the effect of the posterior slope on the long-term outcome of unicompartmental arthroplasty in knees with intact and deficient anterior cruciate ligaments. We retrospectively reviewed the results of ninety-nine unicompartmental arthroplasties after a mean duration of follow-up of sixteen years. At the time of the arthroplasty, the anterior cruciate ligament was considered to be normal in fifty knees, damaged in thirty-one, and absent in eighteen. At the most recent follow-up, we measured the posterior tibial slope and the anterior tibial translation on standing lateral radiographs. The anteroposterior stability of seventy-seven knees that had not been revised by the time of the most recent follow-up was evaluated clinically. In the group of seventy-seven knees that had not been revised by the time of the most recent follow-up, there was a significant linear relationship between anterior tibial translation (mean, 3.7 mm) and posterior tibial slope (mean, 4.3 degrees ) (p < 0.01). The mean posterior slope of the tibial implant was significantly less in the group of seventy-seven knees without loosening of the implant than it was in the group of seventeen knees with loosening of the implant (p < 0.05). Five ruptures of the anterior cruciate ligament occurred in knees in which the ligament had been considered to be normal at the time of implantation; the posterior tibial slope in these five knees was > or = 13 degrees. Clinical evaluation revealed normal or nearly normal anteroposterior stability at the time of the most recent follow-up in all sixty-six unrevised knees in which the anterior cruciate ligament had been present at the time of implantation. Of the eighteen knees in which the anterior cruciate ligament had been absent at the time of the arthroplasty, eleven still had the implant in situ at the time of the most recent follow-up; the mean posterior tibial slope in these eleven knees was <5 degrees. Seven knees in which the anterior cruciate ligament had been absent at the time of the arthroplasty were revised. In these knees, the tibial prosthesis was implanted with a posterior slope of >8 degrees. These findings suggest that >7 degrees of posterior slope of the tibial implant should be avoided, particularly if the anterior cruciate ligament is absent at the time of implantation. An intact anterior cruciate ligament, even when partly degenerated, was associated with the maintenance of normal anteroposterior stability of the knee for an average of sixteen years following unicompartmental knee arthroplasty. Prognostic study, Level II-1 (retrospective study). See Instructions to Authors for a complete description of levels of evidence.

Distal tibial pilon fractures (AO/OTA type B, and C) treated with the external skeletal and minimal internal fixation method.

PubMed

Milenković, Sasa; Mitković, Milorad; Micić, Ivan; Mladenović, Desimir; Najman, Stevo; Trajanović, Miroslav; Manić, Miodrag; Mitković, Milan

2013-09-01

Distal tibial pilon fractures include extra-articular fractures of the tibial metaphysis and the more severe intra-articular tibial pilon fractures. There is no universal method for treating distal tibial pilon fractures. These fractures are treated by means of open reduction, internal fixation (ORIF) and external skeletal fixation. The high rate of soft-tissue complications associated with primary ORIF of pilon fractures led to the use of external skeletal fixation, with limited internal fixation as an alternative technique for definitive management. The aim of this study was to estimate efficacy of distal tibial pilon fratures treatment using the external skeletal and minimal internal fixation method. We presented a series of 31 operated patients with tibial pilon fractures. The patients were operated on using the method of external skeletal fixation with a minimal internal fixation. According to the AO/OTA classification, 17 patients had type B fracture and 14 patients type C fractures. The rigid external skeletal fixation was transformed into a dynamic external skeletal fixation 6 weeks post-surgery. This retrospective study involved 31 patients with tibial pilon fractures, average age 41.81 (from 21 to 60) years. The average follow-up was 21.86 (from 12 to 48) months. The percentage of union was 90.32%, nonunion 3.22% and malunion 6.45%. The mean to fracture union was 14 (range 12-20) weeks. There were 4 (12.19%) infections around the pins of the external skeletal fixator and one (3.22%) deep infections. The ankle joint arthrosis as a late complication appeared in 4 (12.90%) patients. All arthroses appeared in patients who had type C fractures. The final functional results based on the AOFAS score were excellent in 51.61%, good in 32.25%, average in 12.90% and bad in 3.22% of the patients. External skeletal fixation and minimal internal fixation of distal tibial pilon fractures is a good method for treating all types of inta-articular pilon fractures. In fractures types B and C dynamic external skeletal fixation allows early mobility in the ankle joint.

Larger medial femoral to tibial condylar dimension may trigger posterior root tear of medial meniscus.

PubMed

Chung, Jun Young; Song, Hyung Keun; Jung, Myung Kuk; Oh, Hyeong Tak; Kim, Joon Ho; Yoon, Ji-Sang; Min, Byoung-Hyun

2016-05-01

The major meniscal functions are load bearing, load distribution, and shock absorption by increasing the tibiofemoral joint (TFJ) contact area and dissipating axial loads by conversion into hoop stresses. The increased hoop strain stretches the meniscus in outward direction towards radius, causing extrusion, which is associated with the root tear and resultant degenerative osteoarthritis. Since the larger contact area of medial TFJ may increase the hoop stresses, we hypothesized that the larger medial femoral to tibial condylar dimension would contribute to the development of medial meniscus posterior root tear (MMPRT). Thus, the purpose of the study was to assess the relationship between MMPRT and medial femoral to tibial condylar dimension. A case-control study was conducted to compare medial femoral to tibial condylar dimensions of patients with complete MMPRT (n = 59) with those of demography-matched controls (n = 59) during the period from 2010 to 2013. In each patient, MRIs were reviewed and several parameters were measured including articulation width of medial femoral condyle (MFC) at 0°, 30°, 60°, and 90°, medial tibial condyle (MTC) width, degree of meniscal extrusion, and medial femoral to tibial condylar width ratio (MFC/MTC) at 0°, 30°, 60°, and 90°, respectively. Demographic and radiographic data were assessed. A larger medial femoral to tibial condylar dimension was associated with MMPRT at 0° and 30° knee angles. Patients with MFC/MTC greater than 0.9 at 0° also showed about 2.5-fold increase in the chance of MMPRT. Those with meniscal extrusion greater than 3 mm also had about 17.1 times greater chance for the presence of MMPRT accordingly. A larger medial femoral to tibial condylar dimension may be considered as one of the regional contributors to the outbreak of MMPRT, and medial femoral to tibial condylar width ratio greater than 0.9 at 0° knee angle may be considered as a significant risk factor for MMPRT. III.

The Cost-Effectiveness of Surgical Treatment of Medial Unicompartmental Knee Osteoarthritis in Younger Patients

PubMed Central

Konopka, Joseph F.; Gomoll, Andreas H.; Thornhill, Thomas S.; Katz, Jeffrey N.; Losina, Elena

2015-01-01

Background: Surgical options for the management of medial compartment osteoarthritis of the varus knee include high tibial osteotomy, unicompartmental knee arthroplasty, and total knee arthroplasty. We sought to determine the cost-effectiveness of high tibial osteotomy and unicompartmental knee arthroplasty as alternatives to total knee arthroplasty for patients fifty to sixty years of age. Methods: We built a probabilistic state-transition computer model with health states defined by pain, postoperative complications, and subsequent surgical procedures. We estimated transition probabilities from published literature. Costs were determined from Medicare reimbursement schedules. Health outcomes were measured in quality-adjusted life-years (QALYs). We conducted analyses over patients’ lifetimes from the societal perspective, with health and cost outcomes discounted by 3% annually. We used probabilistic sensitivity analyses to account for uncertainty in data inputs. Results: The estimated discounted QALYs were 14.62, 14.63, and 14.64 for high tibial osteotomy, unicompartmental knee arthroplasty, and total knee arthroplasty, respectively. Discounted total direct medical costs were $20,436 for high tibial osteotomy, $24,637 for unicompartmental knee arthroplasty, and $24,761 for total knee arthroplasty (in 2012 U.S. dollars). The incremental cost-effectiveness ratio (ICER) was $231,900 per QALY for total knee arthroplasty and $420,100 per QALY for unicompartmental knee arthroplasty. Probabilistic sensitivity analyses showed that, at a willingness-to-pay (WTP) threshold of $50,000 per QALY, high tibial osteotomy was cost-effective 57% of the time; total knee arthroplasty, 24%; and unicompartmental knee arthroplasty, 19%. At a WTP threshold of $100,000 per QALY, high tibial osteotomy was cost-effective 43% of time; total knee arthroplasty, 31%; and unicompartmental knee arthroplasty, 26%. Conclusions: In fifty to sixty-year-old patients with medial unicompartmental knee osteoarthritis, high tibial osteotomy is an attractive option compared with unicompartmental knee arthroplasty and total knee arthroplasty. This finding supports greater utilization of high tibial osteotomy for these patients. The cost-effectiveness of high tibial osteotomy and of unicompartmental knee arthroplasty depend on rates of conversion to total knee arthroplasty and the clinical outcomes of the conversions. Level of Evidence: Economic Level II. See Instructions for Authors for a complete description of levels of evidence. PMID:25995491

MRI Anatomy of the Tibial ACL Attachment and Proximal Epiphysis in a Large Population of Skeletally Immature Knees: Reference Parameters for Planning Anatomic Physeal-Sparing ACL Reconstruction.

PubMed

Swami, Vimarsha Gopal; Mabee, Myles; Hui, Catherine; Jaremko, Jacob Lester

2014-07-01

To aid in performing anatomic physeal-sparing anterior cruciate ligament (ACL) reconstruction, it is important for surgeons to have reference data for the native ACL attachment positions and epiphyseal anatomy in skeletally immature knees. To characterize anatomic parameters of the ACL tibial insertion and proximal tibial epiphysis at magnetic resonance imaging (MRI) in a large population of skeletally immature knees. Cross-sectional study; Level of evidence, 3. The ACL tibial attachment site and proximal epiphysis were examined in 570 skeletally immature knees with an intact ACL (age, 6-15 years) using 1.5-T proton density-weighted sagittal MRI; also measured were the tibial anteroposterior diameter; anterior, central, and posterior ACL attachment positions; vertical height of the epiphysis; and maximum oblique epiphyseal depth extending from the ACL tibial attachment center to the tibial tuberosity. In adolescents (11-15 years of age), the center of the ACL's tibial attachment was 51.5% ± 5.7% of the anteroposterior diameter of the tibia, with no significant differences between sexes or age groups (P > .05 in all cases). Mean vertical epiphyseal height was 15.9 ± 1.7 mm in the adolescent group, with significant differences between 11-year-olds (15.2 ± 1.5 mm) and 15-year-olds (16.6 ± 1.6 mm), P < .001, and between males (16.6 ± 1.5 mm) and females (14.8 ± 1.4), P < .001. Mean maximum oblique depth was 30.0 ± 5.3 mm, with a significant difference between 11-year-olds (26.7 ± 4.9 mm) and 15-year-olds (32.7 ± 5.1 mm), P < .001, and between males (29.7 ± 6.4 mm) and females (27.8 ± 5.2 mm), P < .001. The maximum oblique depth occurred at a mean angle of ~50°, and this angle did not change with age or sex. There was a significant moderate correlation (r = 0.39, P < .001) between epiphyseal vertical height and maximum oblique depth. The center of the ACL tibial attachment was consistently near 51% of the anteroposterior diameter, regardless of age or sex. The vertical depth of the tibial epiphysis was ~16 mm in adolescents. Maximum oblique depth from ACL attachment was ~30 mm, occurring at a mean angle ~50° regardless of age or sex. The normative values for tibial ACL attachment and epiphyseal anatomy presented here may be helpful in selecting candidates for surgery and in planning surgical approaches for pediatric ACL reconstruction. © 2014 The Author(s).

MRI analysis of tibial PCL attachment in a large population of adult patients: reference data for anatomic PCL reconstruction.

PubMed

Teng, Yuanjun; Guo, Laiwei; Wu, Meng; Xu, Tianen; Zhao, Lianggong; Jiang, Jin; Sheng, Xiaoyun; Xu, Lihu; Zhang, Bo; Ding, Ning; Xia, Yayi

2016-09-05

Consistent reference data used for anatomic posterior cruciate ligament (PCL) reconstruction is not well defined. Quantitative guidelines defining the location of PCL attachment would aid in performing anatomic PCL reconstruction. The purpose was to characterize anatomic parameters of the PCL tibial attachment based on magnetic resonance imaging (MRI) in a large population of adult knees. The PCL tibial attachment site was examined in 736 adult knees with an intact PCL using 3.0-T proton density-weighted sagittal MRI. The outcomes measured were the anterior-posterior diameter (APD) of the tibial plateau; angle between the tibial plateau and the posterior tibial 'shelf' (the slope where the PCL tibial attachment site was) (PTS); length of the PTS; proximal, central, and distal PCL attachment positions as well as the width of the PCL attachment site; and vertical dimension of the PCL attachment site inferior from the tibial plateau. The average APD of the tibia plateau was 33.6 ± 3.5 mm, yielding significant differences between males (35.5 ± 3.0 mm) and females (31.6 ± 2.7 mm), P <.05, and there was a significantly decreasing trend with increasing age in males (P <.05). Mean angle between the tibial plateau and the PTS was 122.4° ± 8.1°, and subgroup analysis showed that the young group had a differently smaller angle (120.9° ± 7.5°) than the middle-aged (123.7° ± 8.2°) and the old (123.4° ± 7.7°) in males population, while there were no significant differences between sexes (P >.05). The proximal, central positions and width of the PCL attachment site were 13.4 ± 3.0 mm, 17.8 ± 3.0 mm and 9.6 ± 2.4 mm along the PTS, with significant differences between males and females (P <.05), and accounted for 60.0 % ± 9.1 %, 80.0 % ± 4.6 % and 43.3 % ± 9.7 % of the PTS respectively, with no significant differences between sexes and among age groups (all P >.05). This study provides reference data of the tibial PCL attachment based on MRI in the sagittal orientation. In analysis of retrospective data from a large population of adult patients, the quantitative values can be used as references to define the inserted angle and depth of the drill guide, and the exact position and size of the tibial PCL tunnel for performing arthroscopic anatomic PCL reconstruction.

Primary Ankle Arthrodesis for Severely Comminuted Tibial Pilon Fractures.

PubMed

Al-Ashhab, Mohamed E

2017-03-01

Management of severely comminuted, complete articular tibial pilon fractures (Rüedi and Allgöwer type III) remains a challenge, with few treatment options providing good clinical outcomes. Twenty patients with severely comminuted tibial pilon fractures underwent primary ankle arthrodesis with a retrograde calcaneal nail and autogenous fibular bone graft. The fusion rate was 100% and the varus malunion rate was 10%. Fracture union occurred at a mean of 16 weeks (range, 13-18 weeks) postoperatively. Primary ankle arthrodesis is a successful method for treating highly comminuted tibial pilon fractures, having a low complication rate and a high satisfaction score. [Orthopedics. 2017; 40(2):e378-e381.]. Copyright 2016, SLACK Incorporated.

Proximal tibial osteotomy. A survivorship analysis.

PubMed

Ritter, M A; Fechtman, R A

1988-01-01

Proximal tibial osteotomy is generally accepted as a treatment for the patient with unicompartmental arthritis. However, a few reports of the long-term results of this procedure are available in the literature, and none have used the technique known as survivorship analysis. This technique has an advantage over conventional analysis because it does not exclude patients for inadequate follow-up, loss to follow-up, or patient death. In this study, survivorship analysis was applied to 78 proximal tibial osteotomies, performed exclusively by the senior author for the correction of a preoperative varus deformity, and a survival curve was constructed. It was concluded that the reliable longevity of the proximal tibial osteotomy is approximately 6 years.

Tibial plateau fracture after anterior cruciate ligament reconstruction: Role of the interference screw resorption in the stress riser effect.

PubMed

Thaunat, Mathieu; Nourissat, Geoffroy; Gaudin, Pascal; Beaufils, Philippe

2006-06-01

We report a case of tibial plateau fracture after previous anterior cruciate ligament (ACL) reconstruction using patellar tendon autograft and bioabsorbable screws 4 years previously. The fracture occurred through the tibial tunnel. The interference screw had undergone complete resorption and the tunnel widening had increased. The resorption of the interference screw did not simultaneously promote and foster the growth of surrounding bone tissue. Therefore, the area of reactive tissue left by the screw resorption in an enlarged bone tunnel may lead to vulnerability of the tibial plateau. Stress risers would occur following ACL reconstruction if either resorption is not complete or bony integration is not complete.

Anterolateral Knee Extra-articular Stabilizers: A Robotic Sectioning Study of the Anterolateral Ligament and Distal Iliotibial Band Kaplan Fibers.

PubMed

Geeslin, Andrew G; Chahla, Jorge; Moatshe, Gilbert; Muckenhirn, Kyle J; Kruckeberg, Bradley M; Brady, Alex W; Coggins, Ashley; Dornan, Grant J; Getgood, Alan M; Godin, Jonathan A; LaPrade, Robert F

2018-05-01

The individual kinematic roles of the anterolateral ligament (ALL) and the distal iliotibial band Kaplan fibers in the setting of anterior cruciate ligament (ACL) deficiency require further clarification. This will improve understanding of their potential contribution to residual anterolateral rotational laxity after ACL reconstruction and may influence selection of an anterolateral extra-articular reconstruction technique, which is currently a matter of debate. Hypothesis/Purpose: To compare the role of the ALL and the Kaplan fibers in stabilizing the knee against tibial internal rotation, anterior tibial translation, and the pivot shift in ACL-deficient knees. We hypothesized that the Kaplan fibers would provide greater tibial internal rotation restraint than the ALL in ACL-deficient knees and that both structures would provide restraint against internal rotation during a simulated pivot-shift test. Controlled laboratory study. Ten paired fresh-frozen cadaveric knees (n = 20) were used to investigate the effect of sectioning the ALL and the Kaplan fibers in ACL-deficient knees with a 6 degrees of freedom robotic testing system. After ACL sectioning, sectioning was randomly performed for the ALL and the Kaplan fibers. An established robotic testing protocol was utilized to assess knee kinematics when the specimens were subjected to a 5-N·m internal rotation torque (0°-90° at 15° increments), a simulated pivot shift with 10-N·m valgus and 5-N·m internal rotation torque (15° and 30°), and an 88-N anterior tibial load (30° and 90°). Sectioning of the ACL led to significantly increased tibial internal rotation (from 0° to 90°) and anterior tibial translation (30° and 90°) as compared with the intact state. Significantly increased internal rotation occurred with further sectioning of the ALL (15°-90°) and Kaplan fibers (15°, 60°-90°). At higher flexion angles (60°-90°), sectioning the Kaplan fibers led to significantly greater internal rotation when compared with ALL sectioning. On simulated pivot-shift testing, ALL sectioning led to significantly increased internal rotation and anterior translation at 15° and 30°; sectioning of the Kaplan fibers led to significantly increased tibial internal rotation at 15° and 30° and anterior translation at 15°. No significant difference was found when anterior tibial translation was compared between the ACL/ALL- and ACL/Kaplan fiber-deficient states on simulated pivot-shift testing or isolated anterior tibial load. The ALL and Kaplan fibers restrain internal rotation in the ACL-deficient knee. Sectioning the Kaplan fibers led to greater tibial internal rotation at higher flexion angles (60°-90°) as compared with ALL sectioning. Additionally, the ALL and Kaplan fibers contribute to restraint of the pivot shift and anterior tibial translation in the ACL-deficient knee. This study reports that the ALL and distal iliotibial band Kaplan fibers restrain anterior tibial translation, internal rotation, and pivot shift in the ACL-deficient knee. Furthermore, sectioning the Kaplan fibers led to significantly greater tibial internal rotation when compared with ALL sectioning at high flexion angles. These results demonstrate increased rotational knee laxity with combined ACL and anterolateral extra-articular knee injuries and may allow surgeons to optimize the care of patients with this injury pattern.

[High tibial osteotomy--fixation by means of external fixation--indication, technique, complications (author's transl)].

PubMed

Klems, H

1976-02-01

High tibial osteotomy has proved its value in the treatment of gonarthrosis with or without axis deformity. The thrust of weight-bearing and other stresses is lessened on the degenerated tibial condyle and transferred to the more normal condyle. The stable fixation by means of external fixation allows early movement of the knee joint.-R-ferences to operative technique, indication, complications and after-treatment.

Knee braces can decrease tibial rotation during pivoting that occurs in high demanding activities.

PubMed

Giotis, Dimitrios; Tsiaras, Vasilios; Ristanis, Stavros; Zampeli, Franceska; Mitsionis, Grigoris; Stergiou, Nicholas; Georgoulis, Anastasios D

2011-08-01

The purpose of this study was to investigate whether knee braces could effectively decrease tibial rotation during high demanding activities. Using an in vivo three-dimensional kinematic analysis, 21 physically active, healthy, male subjects were evaluated. Each subject performed two tasks that were used extensively in the literature because they combine increased rotational and translational loads on the knee, (1) descending from a stair and subsequent pivoting and (2) landing from a platform and subsequent pivoting under three conditions: (A) wearing a prophylactic brace (braced), (B) wearing a patellofemoral brace (sleeved), and (C) unbraced condition. In the first task, tibial rotation during the pivoting phase was significantly decreased in the braced condition as compared to the sleeved condition (P = 0.019) and the non-braced condition (P = 0.002). In the second task, the same variable was significantly decreased in the braced condition as compared to the sleeved (P = 0.001) and the unbraced condition (P < 0.001). The sleeved condition also produced significantly decreased tibial rotation with respect to the unbraced condition (P = 0.021). Bracing decreased tibial rotation in activities where increased translational and rotational forces were applied. Because knee braces decreased tibial rotation, they can possibly be used with ACL-reconstructed and ACL-deficient patients to prevent such problems. Case-control study, Level III.

Does Tibial Slope Affect Perception of Coronal Alignment on a Standing Anteroposterior Radiograph?

PubMed

Schwartz, Adam J; Ravi, Bheeshma; Kransdorf, Mark J; Clarke, Henry D

2017-07-01

A standing anteroposterior (AP) radiograph is commonly used to evaluate coronal alignment following total knee arthroplasty (TKA). The impact of coronal alignment on TKA outcomes is controversial, perhaps due to variability in imaging and/or measurement technique. We sought to quantify the effect of image rotation and tibial slope on coronal alignment. Using a standard extramedullary tibial alignment guide, 3 cadaver legs were cut to accept a tibial tray at 0°, 3°, and 7° of slope. A computed tomography scan of the entire tibia was obtained for each specimen to confirm neutral coronal alignment. Images were then obtained at progressive 10° intervals of internal and external rotation up to 40° maximum in each direction. Images were then randomized and 5 blinded TKA surgeons were asked to determine coronal alignment. Continuous data values were transformed to categorical data (neutral [0], valgus [L], and varus [R]). Each 10° interval of external rotation of a 7° sloped tibial cut (or relative internal rotation of a tibial component viewed in the AP plane) resulted in perception of an additional 0.75° of varus. The slope of the proximal tibia bone cut should be taken into account when measuring coronal alignment on a standing AP radiograph. Copyright © 2017 Elsevier Inc. All rights reserved.

Sequential avulsions of the tibial tubercle in an adolescent basketball player.

PubMed

Huang, Ying Chieh; Chao, Ying-Hao; Lien, Fang-Chieh

2010-05-01

Tibial tubercle avulsion is an uncommon fracture in physically active adolescents. Sequential avulsion of tibial tubercles is extremely rare. We reported a healthy, active 15-year-old boy who suffered from left tibial tubercle avulsion fracture during a basketball game. He received open reduction and internal fixation with two smooth Kirschner wires and a cannulated screw, with every effort to reduce the plate injury. Long-leg splint was used for protection followed by programmed rehabilitation. He recovered uneventfully and returned to his previous level of activity soon. Another avulsion fracture happened at the right tibial tubercle 3.5 months later when he was playing the basketball. From the encouragement of previous successful treatment, we provided him open reduction and fixation with two small-caliber screws. He recovered uneventfully and returned to his previous level of activity soon. No genu recurvatum or other deformity was happening in our case at the end of 2-year follow-up. No evidence of Osgood-Schlatter disease or osteogenesis imperfecta was found. Sequential avulsion fractures of tibial tubercles are rare. Good functional recovery can often be obtained like our case if we treat it well. To a physically active adolescent, we should never overstate the risk of sequential avulsion of the other leg to postpone the return to an active, functional life.

Tibial nerve stimulation to inhibit the micturition reflex by an implantable wireless driver microstimulator in cats

PubMed Central

Li, Xing; Liao, Li-Min; Chen, Guo-Qing; Wang, Zhao-Xia; Lu, Tian-Ji; Deng, Han; Loeb, Gerald-E

2016-01-01

Abstract Background: Traditional tibial nerve stimulation (TNS) has been used to treat overactive bladder syndrome (OAB), but there are some shortcomings. Thus, a novel alternative is needed for the treatment of OAB. The study investigated the effects of a new type of tibial nerve microstimulator on the micturition reflex in cats. Methods: An implantable wireless driver microstimulator was implanted around the tibial nerve in 9 α-chloralose anesthetized cats. Cystometry was performed by infusing 0.9% normal saline (NS) or 0.25% acetic acid (AA) through a urethral catheter. Multiple cystometrograms were performed before, during, and after TNS to determine the inhibitory effect of the microstimulator on the micturition reflex. Results: TNS at 2 threshold (T) intensity significantly increased the bladder capacity (BC) during NS infusion. Bladder overactivity was irritated by the intravesical infusion of 0.25% AA, which significantly reduced the BC compared with the NS infusion. TNS at 2 T intensity suppressed AA-induced bladder overactivity and significantly increased the BC compared with the AA control. Conclusion: The implantable wireless driver tibial nerve microstimulator appears to be effective in inhibiting the micturition reflex during physiologic and pathologic conditions. The implantable wireless driver tibial nerve microstimulator could be used to treat OAB. PMID:27537576

[Mobility of a polyethylene tibial insert in a mobile total knee prosthesis].

PubMed

Castel, E; Roger, B; Camproux, A; Saillant, G

1999-03-01

We have studied the mobility of a mobile tibial implant in total knee arthroplasty (TKA) by a radiographical evaluation. We analyzed mobility of the polyethylene tibial insert of 15 "G2S" TKA implanted for one year or more. We established a dynamic radiographical evaluation. We used 3 weight-bearing radiographs: AP in extension and two lateral (one in extension and one at 90 degrees of flexion), two AP with femoral internal and external rotation, 2 strict lateral X-rays in neutral rotation in antero-posterior replacement with a 25 kilograms strength Telos, and 2 AP in varus and valgus with Telos. Wilcoxon's test and Fisher's exact test were used for statistical evaluation. Our study demonstrated preservation of the polyethylene mobility in tibial TKA implant in all movements: in rotation, in antero-posterior translation with Telos, and even in antero-posterior translation during physiological condition with flexion-extension weight-bearing radiographs. Statistical tests were very significant. We noticed that flexion induced anterior translation of tibial polyethylene when PCL was preserved. This study answered to our question whether mobility of TKA tibial implant persists after implantation. This mobility should reduce loosening forces to the tibia and stress in the polyethylene component. Now we have to determine the amplitude of mobility required to reach this objective.

Gender differences in knee kinematics and muscle activity during single limb drop landing.

PubMed

Nagano, Yasuharu; Ida, Hirofumi; Akai, Masami; Fukubayashi, Toru

2007-06-01

The likelihood of sustaining an ACL injury in a noncontact situation is two to eight times greater for females than for males. However, the mechanism and risk factors of ACL injury are still unknown. We compared knee kinematics as well as electromyographic activity during landing between male and female athletes. Eighteen male athletes and nineteen female athletes participated in the experiment. The angular displacements of flexion/extension, valgus/varus, and internal/external tibial rotation, as well as the translational displacements of anterior/posterior tibial translation during single limb drop landing were calculated. Simultaneous electromyographical activity of the rectus femoris (RF) and hamstrings (Ham) was taken. During landing, internal tibial rotation of the females was significantly larger than that of the males, while differences were not observed in flexion, varus, valgus, and anterior tibial translation. Hamstrings/quadriceps ratio (HQR) for the 50 ms time period before foot contact was greater in males than in females. The mechanism of noncontact ACL injury during a single limb drop landing would be internal tibial rotation combined with valgus rotation of the knee. Increased internal tibial rotation combined with greater quadriceps activity and a low HQR could be one reason female athletes have a higher incidence of noncontact ACL injuries.

Influence of medial parapatellar nail insertion on alignment in proximal tibia fractures--special consideration of the fracture level.

PubMed

Weninger, Patrick; Tschabitscher, Manfred; Traxler, Hannes; Pfafl, Veronika; Hertz, Harald

2010-04-01

Although a lateral starting point for tibial nailing is recommended to avoid valgus misalignment, higher rates of intra-articular damage were described compared with a medial parapatellar approach. The aim of this anatomic study was to evaluate the fracture level allowing for a safe medial nail entry point without misalignment or dislocation of fragments. Thirty-two fresh-frozen cadaver lower extremities were used to create 1-cm osteotomies at four different levels (n = 8) from 2 cm to 8 cm below the tibial tuberosity. Nine-millimeter unreamed solid titanium tibial nails (Connex, I.T.S. Spectromed, Lassnitzhohe, Austria) were inserted from a medial parapatellar incision. Misalignment (degree) and dislocation of the distal fragment were measured in the frontal and sagittal plane. A medial parapatellar approach for tibial nail insertion mainly caused valgus and anterior bow misalignment and ventral and medial fragment displacement. Mean misalignment and fragment displacement did not exceed 0.5 degree if the osteotomy was performed 8 cm to 9 cm below the tibial tuberosity. According to the results of this study, a medial parapatellar approach can be performed without misalignment and fragment dislocation in proximal tibia fractures extending 8 cm or more below the tibial tuberosity.

The role of the deep medial collateral ligament in controlling rotational stability of the knee.

PubMed

Cavaignac, Etienne; Carpentier, Karel; Pailhé, Regis; Luyckx, Thomas; Bellemans, Johan

2015-10-01

The tibial insertion of the deep medial collateral ligament (dMCL) is frequently sacrificed when the proximal tibial cut is performed during total knee arthroplasty. The role of the dMCL in controlling the knee's rotational stability is still controversial. The aim of this study was to quantify the rotational laxity induced by an isolated lesion of the dMCL as it occurs during tibial preparation for knee arthroplasty. An isolated resection of the deep MCL was performed in 10 fresh-frozen cadaver knees. Rotational laxity was measured during application of a standard 5.0 N.m rotational torque. Maximal tibial rotation was measured at different knee flexion angles using an image-guided navigation system (Medivision Surgetics system, Praxim, Grenoble, France) before and after dMCL resection. In all cases, internal and external tibial rotation increased after dMCL resection. Total rotational laxity increased significantly for all knee flexion angles, with an average difference of +7.8° (SD 5.7) with the knee in extension, +8.9° (SD 1.9) in 30° flexion, +7° (SD 2.9) in 60° flexion and +5.3° (SD 2.8) in 90° flexion. Sacrificing the tibial insertion of the deep MCL increases rotational laxity of the knee by 5°-9°, depending on the knee flexion angle. Based on our findings, new surgical techniques and implants that preserve the dMCL insertion such as tibial inlay components should be developed. Further clinical evaluations are necessary.

A cadaveric investigation into the demographic and bony alignment properties associated with osteoarthritis of the patellofemoral joint.

PubMed

Weinberg, Douglas S; Tucker, Braden J; Drain, Joseph P; Wang, David M; Gilmore, Allison; Liu, Raymond W

2016-06-01

Patellofemoral joint osteoarthritis is common, although circumstances dictating its evolution and pathogenesis remain unclear. Advances in surgical technique have improved the ability to modify long-bone alignment in the coronal, sagittal, and axial planes. However, to our knowledge, there is no significant long-term data available in regard to the relationship between anatomic alignment parameters most amenable to surgical modification and patellofemoral joint osteoarthritis. Five-hundred and seventy-one cadaveric skeletons were obtained from the Hamann-Todd osteological collection. Mechanical lateral distal femoral angle, medial proximal tibial angle, tibial slope, femoral version, tibial torsion, the position of the tibial tubercle relative to the width of the tibial plateau, trochlear depth, and patellar size were measured using validated techniques. A previously published grading system for patellofemoral joint arthritis was used to quantify macroscopic signs of degenerative joint disease. Increasing age (standardized beta 0.532, p<0.001), female gender (standardized beta 0.201, p=0.002), and decreasing mechanical lateral distal femoral angle (standardized beta -0.128, p=0.025) were independent correlates of increased patellofemoral joint osteoarthritis. A relatively more laterally positioned tibial tubercle trended towards predicting patellofemoral joint osteoarthritis (standardized beta 0.080, p=0.089). These findings confirm that patellofemoral joint osteoarthritis is strongly associated with increasing age and female gender. Valgus alignment of the distal femur, a relatively more lateral location of the tibial tubercle, and a shallower trochlear grove appear to have modest effects on the development of patellofemoral joint osteoarthritis. Copyright © 2016 Elsevier B.V. All rights reserved.

Correlation between hindfoot joint three-dimensional kinematics and the changes of the medial arch angle in stage II posterior tibial tendon dysfunction flatfoot.

PubMed

Zhang, Yi-Jun; Xu, Jian; Wang, Yue; Lin, Xiang-Jin; Ma, Xin

2015-02-01

The aim of this study was to explore the correlation between the kinematics of the hindfoot joint and the medial arch angle change in stage II posterior tibial tendon dysfunction flatfoot three-dimensionally under loading. Computed tomography (CT) scans of 12 healthy feet and 12 feet with stage II posterior tibial tendon dysfunction flatfoot were taken both in non- and full-body-weight-bearing condition. The CT images of the hindfoot bones were reconstructed into three-dimensional models with Mimics and Geomagic reverse engineering software. The three-dimensional changes of the hindfoot joint were calculated to determine their correlation to the medial longitudinal arch angle. The medial arch angle change was larger in stage II posterior tibial tendon dysfunction flatfoot compared to that in healthy foot under loading. The rotation and translation of the talocalcaneal joint, the talonavicular joint and the calcanocuboid joint had little influence on the change of the medial arch angle in healthy foot. However, the eversion of the talocalcaneal joint, the proximal translation of the calcaneus relative to the talus and the dorsiflexion of talonavicular joint could increase the medial arch angle in stage II posterior tibial tendon dysfunction flatfoot under loading. Joint instability occurred in patients with stage II posterior tibial tendon dysfunction flatfoot under loading. Limitation of over movement of the talocalcaneal joint and the talonavicular joint may help correct the medial longitudinal arch in stage II posterior tibial tendon dysfunction flatfoot. Copyright © 2014 Elsevier Ltd. All rights reserved.

The effects of sectioning the spring ligament on rearfoot stability and posterior tibial tendon efficiency.

PubMed

Jennings, Meagan M; Christensen, Jeffery C

2008-01-01

Posterior tibial tendon insufficiency has been implicated as a cause of adult acquired flatfoot. Multiple theories are debated as to whether or not a flatfoot deformity develops secondary to insufficiency of the posterior tibial tendon or of the ligamentous structures such as the spring ligament complex. This cadaveric study was undertaken in an attempt to determine the effect that sectioning the spring ligament complex has on foot stability, and whether engagement of the posterior tibial tendon would be able to compensate for the loss of the spring ligament complex. A 3-dimensional kinematic system and a custom-loading frame were used to quantify rotation about the talus, navicular, and calcaneus in 5 cadaveric specimens, before and after sectioning the spring ligament complex, while incremental tension was applied to the posterior tibial tendon. This study demonstrated that sectioning the spring ligament complex created instability in the foot for which the posterior tibial tendon was unable to compensate. Sectioning the spring ligament complex also produced significant changes in talar, navicular, and calcaneal rotations. During simulated midstance, the navicular plantarflexed, adducted, and everted; the talar head plantarflexed, adducted, and inverted; and the calcaneus plantarflexed, abducted, and everted, after sectioning the spring ligament complex. The results of this study indicate that the spring ligament complex is the major stabilizer of the arch during midstance and that the posterior tibial tendon is incapable of fully accommodating for its insufficiency, suggesting that the spring ligament complex should be evaluated and, if indicated, repaired in flatfoot reconstruction. 5.

Perforating and deep lymphatic vessels in the knee region: an anatomical study and clinical implications.

PubMed

Pan, Wei-Ren; Zeng, Fan-Qiang; Wang, De-Guang; Qiu, Zhi-Qiang

2017-05-01

To determine the relationship between the perforating and deep lymphatic vessels in the knee region for clinical implications. Four lower limbs from two unembalmed human cadavers were used. Under a surgical microscope, 6% hydrogen peroxide was employed to detect lymph vessels accompanying the small saphenous vein, anterior tibial, posterior tibial and fibular blood vessels all commencing from distal ends of specimens. Each lymphatic vessel was inserted by a 30-gauge needle and injected with a barium sulphate mixture. Each specimen was dissected, radiographed and photographed to determine the perforating and deep lymphatic vessels in the region. A perforating lymph vessel was observed in the popliteal fossa of each specimen. It arose from the superficial popliteal lymph node and terminated in the deep popliteal lymph node. The anterior tibial, posterior tibial and peroneal lymph vessels were discovered in the region travelling with the corresponding vascular bundles. After penetrating the vascular aperture of the interosseous membrane between the tibia and fibula, the anterior tibial lymph vessel entered directly into the deep popliteal lymph node or converged to either the posterior tibial or fibular lymph vessel, before entering the node. The posterior tibial and peroneal lymph vessels entered the deep popliteal lymph node. The efferent lymph vessel of the deep popliteal lymph node travelled with the femoral vascular bundle. The perforating and deep lymphatic vessels in the knee region has been presented and discussed. The information advances our anatomical knowledge and the results will benefit clinical management. © 2017 Royal Australasian College of Surgeons.

Bone stress in runners with tibial stress fracture.

PubMed

Meardon, Stacey A; Willson, John D; Gries, Samantha R; Kernozek, Thomas W; Derrick, Timothy R

2015-11-01

Combinations of smaller bone geometry and greater applied loads may contribute to tibial stress fracture. We examined tibial bone stress, accounting for geometry and applied loads, in runners with stress fracture. 23 runners with a history of tibial stress fracture & 23 matched controls ran over a force platform while 3-D kinematic and kinetic data were collected. An elliptical model of the distal 1/3 tibia cross section was used to estimate stress at 4 locations (anterior, posterior, medial and lateral). Inner and outer radii for the model were obtained from 2 planar x-ray images. Bone stress differences were assessed using two-factor ANOVA (α=0.05). Key contributors to observed stress differences between groups were examined using stepwise regression. Runners with tibial stress fracture experienced greater anterior tension and posterior compression at the distal tibia. Location, but not group, differences in shear stress were observed. Stepwise regression revealed that anterior-posterior outer diameter of the tibia and the sagittal plane bending moment explained >80% of the variance in anterior and posterior bone stress. Runners with tibial stress fracture displayed greater stress anteriorly and posteriorly at the distal tibia. Elevated tibial stress was associated with smaller bone geometry and greater bending moments about the medial-lateral axis of the tibia. Future research needs to identify key running mechanics associated with the sagittal plane bending moment at the distal tibia as well as to identify ways to improve bone geometry in runners in order to better guide preventative and rehabilitative efforts. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of axial tibial torque direction on ACL relative strain and strain rate in an in vitro simulated pivot landing.

PubMed

Oh, Youkeun K; Kreinbrink, Jennifer L; Wojtys, Edward M; Ashton-Miller, James A

2012-04-01

Anterior cruciate ligament (ACL) injuries most frequently occur under the large loads associated with a unipedal jump landing involving a cutting or pivoting maneuver. We tested the hypotheses that internal tibial torque would increase the anteromedial (AM) bundle ACL relative strain and strain rate more than would the corresponding external tibial torque under the large impulsive loads associated with such landing maneuvers. Twelve cadaveric female knees [mean (SD) age: 65.0 (10.5) years] were tested. Pretensioned quadriceps, hamstring, and gastrocnemius muscle-tendon unit forces maintained an initial knee flexion angle of 15°. A compound impulsive test load (compression, flexion moment, and internal or external tibial torque) was applied to the distal tibia while recording the 3D knee loads and tibofemoral kinematics. AM-ACL relative strain was measured using a 3 mm DVRT. In this repeated measures experiment, the Wilcoxon signed-rank test was used to test the null hypotheses with p < 0.05 considered significant. The mean (±SD) peak AM-ACL relative strains were 5.4 ± 3.7% and 3.1 ± 2.8% under internal and external tibial torque, respectively. The corresponding mean (± SD) peak AM-ACL strain rates reached 254.4 ± 160.1%/s and 179.4 ± 109.9%/s, respectively. The hypotheses were supported in that the normalized mean peak AM-ACL relative strain and strain rate were 70 and 42% greater under internal than under external tibial torque, respectively (p = 0.023, p = 0.041). We conclude that internal tibial torque is a potent stressor of the ACL because it induces a considerably (70%) larger peak strain in the AM-ACL than does a corresponding external tibial torque. Copyright © 2011 Orthopaedic Research Society.

Comparison of Bioabsorbable Interference Screws Composed of Poly-l-lactic Acid and Hydroxyapatite (PLLA-HA) to WasherLoc Tibial Fixation in Patients After Anterior Cruciate Ligament Reconstruction of the Knee Joint.

PubMed

Patkowski, Mateusz; Królikowska, Aleksandra; Reichert, Paweł

2016-01-01

The reconstruction of the anterior cruciate ligament (ACL) of the knee joint is a standard in ACL complete rupture treatment in athletes. One of the weakest points of this procedure is tibial fixation of grafts. The aim was, firstly, to evaluate patients 3-4 years after primary ACL reconstruction with the use of autologous ipsilateral STGR grafts and with tibial fixation using a bioabsorbable interference screw composed of PLLA-HA or WasherLoc, comparing the postoperative result to the preoperative condition and, secondly, to compare the results between the two groups of patients with different tibial fixation. Group I consisted of 20 patients with a bioabsorbable interference screw composed of PLLA-HA tibial fixation. In Group II, there were 22 patients after ACL reconstruction with the use of WasherLoc tibial fixation. The Lachman test, pivot-shift test, Lysholm Knee Scoring Scale and 2000 International Knee Documentation Committee (2000 IKDC) Subjective Knee Evaluation Form were used to evaluate the results. The intra-group comparison of the results of the 2000 IKDC Subjective Knee Evaluation Form and Lysholm Knee Scoring Scale obtained in the groups studied showed statistically significant differences between the evaluation performed preoperatively and postoperatively. The inter-group comparison of the results of the 2000 IKDC Subjective Knee Evaluation Form and Lysholm Knee Scoring Scale obtained postoperatively showed no statistically significant differences between the two groups. An evaluation 3-4 years after ACL reconstruction with the use of autologous ipsilateral STGR grafts demonstrated significant progress from the preoperative condition to the postoperative result in patients with tibial fixation using a bioabsorbable interference screw composed of PLLA-HA as well as in patients with WasherLoc tibial fixation. There were no differences found between the two groups of patients after ACL reconstruction in terms of manual stability testing or a subjective assessment of knee joint outcomes.

Tibial Eminence Involvement With Tibial Plateau Fracture Predicts Slower Recovery and Worse Postoperative Range of Knee Motion.

PubMed

Konda, Sanjit R; Driesman, Adam; Manoli, Arthur; Davidovitch, Roy I; Egol, Kenneth A

2017-07-01

To examine 1-year functional and clinical outcomes in patients with tibial plateau fractures with tibial eminence involvement. Retrospective analysis of prospectively collected data. Academic Medical Center. All patients who presented with a tibial plateau fracture (Orthopaedic Trauma Association (OTA) 41-B and 41-C). Patients were divided into fractures with a tibial eminence component (+TE) and those without (-TE) cohorts. All patients underwent similar surgical approaches and fixation techniques for fractures. No tibial eminence fractures received fixation specifically. Short musculoskeletal functional assessment (SMFA), pain (Visual Analogue Scale), and knee range-of-motion (ROM) were evaluated at 3, 6, and 12 months postoperatively and compared between cohorts. Two hundred ninety-three patients were included for review. Patients with OTA 41-C fractures were more likely to have an associated TE compared with 41-B fractures (63% vs. 28%, P < 0.01). At 3 months postoperatively, the +TE cohort was noted to have worse knee ROM (75.16 ± 51 vs. 86.82 ± 53 degree, P = 0.06). At 6 months, total SMFA and knee ROM was significantly worse in the +TE cohort (29 ± 17 vs. 21 ± 18, P ≤ 0.01; 115.6 ± 20 vs. 124.1 ± 15, P = 0.01). By 12 months postoperatively, only knee ROM remained significantly worse in the +TE cohort (118.7 ± 15 vs. 126.9 ± 13, P < 0.01). Multivariate analysis revealed that tibial eminence involvement was a significant predictor of ROM at 6 and 12 months and SFMA at 6 months. Body mass index was found to be a significant predictor of ROM and age was a significant predictor of total SMFA at all time points. Knee ROM remains worse throughout the postoperative period in the +TE cohort. Functional outcome improves less rapidly in the +TE cohort but achieves similar results by 1 year. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Cemented all-polyethylene and metal-backed polyethylene tibial components used for primary total knee arthroplasty: a systematic review of the literature and meta-analysis of randomized controlled trials involving 1798 primary total knee implants.

PubMed

Voigt, Jeffrey; Mosier, Michael

2011-10-05

The cost of the implant as part of a total knee arthroplasty accounts for a substantial portion of the costs for the overall procedure: all-polyethylene tibial components cost considerably less than cemented metal-backed tibial components. We performed a systematic review of the literature to determine whether the clinical results of lower-cost all-polyethylene tibial components were comparable with the results of a more expensive metal-backed tibial component. We searched The Cochrane Library, MEDLINE, EMBASE, EBSCO CINAHL, the bibliographies of identified articles, orthopaedic meeting abstracts, health technology assessment web sites, and important orthopaedic journals. This search was performed for the years 1990 to the present. No language restriction was applied. We restricted our search to Level-I studies involving participants who received either an all-polyethylene or a metal-backed tibial implant. The primary outcome measures were durability, function, and adverse events. Two reviewers independently screened the papers for inclusion, assessed trial quality, and extracted data. Effects estimates were pooled with use of fixed and random-effects models of risk ratios, calculated with 95% confidence intervals. Heterogeneity was assessed with the I2 statistic. Forest plots were also generated. Data on 1798 primary total knee implants from twelve studies were analyzed. In all studies, the median or mean age of the participants was greater than sixty-seven years, with a majority of the patients being female. There was no difference between patients managed with an all-polyethylene tibial component and those managed with a metal-backed tibial component in terms of adverse events. There was no significant difference between the two groups in terms of the durability of the implants at two, ten, and fifteen years postoperatively, regardless of the year or how durability was defined (revision or radiographic failure). Finally, with use of a variety of validated measures, there was no difference between the two groups in terms of functional status at two, eight, and ten years, regardless of the measure used. A less expensive all-polyethylene component as part of a total knee arthroplasty has results equivalent to those obtained with a cemented metal-backed tibial component. Using a total knee implant with a cemented all-polyethylene tibial component could save the healthcare system substantial money while obtaining equivalent results to more expensive cemented designs and materials.

Resonant ion acceleration by plasma jets: Effects of jet breaking and the magnetic-field curvature.

PubMed

Artemyev, A V; Vasiliev, A A

2015-05-01

In this paper we consider resonant ion acceleration by a plasma jet originating from the magnetic reconnection region. Such jets propagate in the background magnetic field with significantly curved magnetic-field lines. Decoupling of ion and electron motions at the leading edge of the jet results in generation of strong electrostatic fields. Ions can be trapped by this field and get accelerated along the jet front. This mechanism of resonant acceleration resembles surfing acceleration of charged particles at a shock wave. To describe resonant acceleration of ions, we use adiabatic theory of resonant phenomena. We show that particle motion along the curved field lines significantly influences the acceleration rate. The maximum gain of energy is determined by the particle's escape from the system due to this motion. Applications of the proposed mechanism to charged-particle acceleration in the planetary magnetospheres and the solar corona are discussed.

Fracture of the proximal tibia after revision total knee arthroplasty with an extensor mechanism allograft.

PubMed

Klein, Gregg R; Levine, Harlan B; Sporer, Scott M; Hartzband, Mark A

2013-02-01

Extensor mechanism reconstruction with an extensor mechanism allograft (EMA) remains one of the most reliable methods for treating the extensor mechanism deficient total knee arthroplasty. We report 3 patients who were treated with an EMA who sustained a proximal tibial shaft fracture. In all 3 cases, a short tibial component was present that ended close to the level of the distal extent of the bone block. When performing an EMA, it is important to recognize that the tibial bone block creates a stress riser and revision to a long-stemmed tibial component should be strongly considered to bypass this point to minimize the risk of fracture. Copyright © 2013 Elsevier Inc. All rights reserved.

Racetrack-shape fixed field induction accelerator for giant cluster ions

NASA Astrophysics Data System (ADS)

Takayama, Ken; Adachi, Toshikazu; Wake, Masayoshi; Okamura, Katsuya

2015-05-01

A novel scheme for a racetrack-shape fixed field induction accelerator (RAFFIA) capable of accelerating extremely heavy cluster ions (giant cluster ions) is described. The key feature of this scheme is rapid induction acceleration by localized induction cells. Triggering the induction voltages provided by the signals from the circulating bunch allows repeated acceleration of extremely heavy cluster ions. The given RAFFIA example is capable of realizing the integrated acceleration voltage of 50 MV per acceleration cycle. Using 90° bending magnets with a reversed field strip and field gradient is crucial for assuring orbit stability in the RAFFIA.

Non-Maximal Tripartite Entanglement Degradation of Dirac and Scalar Fields in Non-Inertial Frames

NASA Astrophysics Data System (ADS)

Salman, Khan; Niaz, Ali Khan; M. K., Khan

2014-03-01

The π-tangle is used to study the behavior of entanglement of a nonmaximal tripartite state of both Dirac and scalar fields in accelerated frame. For Dirac fields, the degree of degradation with acceleration of both one-tangle of accelerated observer and π-tangle, for the same initial entanglement, is different by just interchanging the values of probability amplitudes. A fraction of both one-tangles and the π-tangle always survives for any choice of acceleration and the degree of initial entanglement. For scalar field, the one-tangle of accelerated observer depends on the choice of values of probability amplitudes and it vanishes in the range of infinite acceleration, whereas for π-tangle this is not always true. The dependence of π-tangle on probability amplitudes varies with acceleration. In the lower range of acceleration, its behavior changes by switching between the values of probability amplitudes and for larger values of acceleration this dependence on probability amplitudes vanishes. Interestingly, unlike bipartite entanglement, the degradation of π-tangle against acceleration in the case of scalar fields is slower than for Dirac fields.

Measurement of bone mineral density in the tunnel regions for anterior cruciate ligament reconstruction by dual-energy X-ray absorptiometry, computed tomography scan, and the immersion technique based on Archimedes' principle.

PubMed

Tie, Kai; Wang, Hua; Wang, Xin; Chen, Liaobin

2012-10-01

To determine, for anterior cruciate ligament (ACL) reconstruction, whether the bone mineral density (BMD) of the femoral tunnel was higher than that of the tibial tunnel, to provide objective evidence for choosing the appropriate diameter of interference screws. Two groups were enrolled. One group comprised 30 normal volunteers, and the other comprised 9 patients with ACL rupture. Dual-energy X-ray absorptiometry was used to measure the BMD of the femoral and tibial tunnel regions of the volunteers' right knees by choosing a circular area covering the screw fixation region. The knees were also scanned by spiral computed tomography (CT), and the 3-dimensional reconstruction technique was used to determine the circular sections passing through the longitudinal axis of the femoral and tibial tunnels. Grayscale CT values of the cross-sectional area were measured. Cylindrical cancellous bone blocks were removed from the femoral and tibial tunnels during the ACL reconstruction for the patients. The volumetric BMD of the bone blocks was measured using a standardized immersion technique according to Archimedes' principle. As measured by dual-energy X-ray absorptiometry, the BMD of the femoral and tibial tunnel regions was 1.162 ± 0.034 g/cm(2) and 0.814 ± 0.038 g/cm(2), respectively (P < .01). The CT value of the femoral tunnel region was 211.7 ± 11.5 Hounsfield units, and the value of the tibial tunnel region was 104.9 ± 7.4 Hounsfield units (P < .01). The volumetric BMD of the bone block from the femoral tunnel (2.80 ± 0.88 g/cm(3)) was higher than the value from the tibial tunnel (1.88 ± 0.59 g/cm(3)) (P < .01). Comparing the data between male and female patients, we found no significant difference in both femoral and tibial tunnel regions. For ACL reconstruction, the BMD of the femoral tunnel is higher than that of the tibial tunnel. This implies that a proportionally larger-diameter interference screw should be used for fixation in the proximal tibia than that used for fixation in the distal femur. Level IV, therapeutic case series. Copyright © 2012 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Global rotation has high sensitivity in ACL lesions within stress MRI.

PubMed

Espregueira-Mendes, João; Andrade, Renato; Leal, Ana; Pereira, Hélder; Skaf, Abdala; Rodrigues-Gomes, Sérgio; Oliveira, J Miguel; Reis, Rui L; Pereira, Rogério

2017-10-01

This study aims to objectively compare side-to-side differences of P-A laxity alone and coupled with rotatory laxity within magnetic resonance imaging, in patients with total anterior cruciate ligament (ACL) rupture. This prospective study enrolled sixty-one patients with signs and symptoms of unilateral total anterior cruciate ligament rupture, which were referred to magnetic resonance evaluation with simultaneous instrumented laxity measurements. Sixteen of those patients were randomly selected to also have the contralateral healthy knee laxity profile tested. Images were acquired for the medial and lateral tibial plateaus without pressure, with postero-anterior translation, and postero-anterior translation coupled with maximum internal and external rotation, respectively. All parameters measured were significantly different between healthy and injured knees (P < 0.05), with exception of lateral plateau without stress. The difference between injured and healthy knees for medial and lateral tibial plateaus anterior displacement (P < 0.05) and rotation (P < 0.001) was statistically significant. It was found a significant correlation between the global rotation of the lateral tibial plateau (lateral plateau with internal + external rotation) with pivot-shift, and between the anterior global translation of both tibial plateaus (medial + lateral tibial plateau) with Lachman. The anterior global translation of both tibial plateaus was the most specific test with a cut-off point of 11.1 mm (93.8 %), and the global rotation of the lateral tibial plateau was the most sensitive test with a correspondent cut-off point of 15.1 mm (92.9 %). Objective laxity quantification of ACL-injured knees showed increased sagittal laxity, and simultaneously in sagittal and transversal planes, when compared to their healthy contralateral knee. Moreover, when measuring instability from anterior cruciate ligament ruptures, the anterior global translation of both tibial plateaus and global rotation of the lateral tibial plateau add diagnostic specificity and sensitivity. This work strengthens the evidence that the anterior cruciate ligament plays an important biomechanical role in controlling the anterior translation, but also both internal and external rotation. The high sensitivity and specificity of this device in objectively identifying and measuring the multiplanar instability clearly guides stability restoration clinical procedures. Level of evidence Cross-sectional study, Level III.

Testing the effectiveness and the contribution of experimental supercharge (reversed) end-to-side nerve transfer.

PubMed

Nadi, Mustafa; Ramachandran, Sudheesh; Islam, Abir; Forden, Joanne; Guo, Gui Fang; Midha, Rajiv

2018-05-18

OBJECTIVE Supercharge end-to-side (SETS) transfer, also referred to as reverse end-to-side transfer, distal to severe nerve compression neuropathy or in-continuity nerve injury is gaining clinical popularity despite questions about its effectiveness. Here, the authors examined SETS distal to experimental neuroma in-continuity (NIC) injuries for efficacy in enhancing neuronal regeneration and functional outcome, and, for the first time, they definitively evaluated the degree of contribution of the native and donor motor neuron pools. METHODS This study was conducted in 2 phases. In phase I, rats (n = 35) were assigned to one of 5 groups for unilateral sciatic nerve surgeries: group 1, tibial NIC with distal peroneal-tibial SETS; group 2, tibial NIC without SETS; group 3, intact tibial and severed peroneal nerves; group 4, tibial transection with SETS; and group 5, severed tibial and peroneal nerves. Recovery was evaluated biweekly using electrophysiology and locomotion tasks. At the phase I end point, after retrograde labeling, the spinal cords were analyzed to assess the degree of neuronal regeneration. In phase II, 20 new animals underwent primary retrograde labeling of the tibial nerve, following which they were assigned to one of the following 3 groups: group 1, group 2, and group 4. Then, secondary retrograde labeling from the tibial nerve was performed at the study end point to quantify the native versus donor regenerated neuronal pool. RESULTS In phase I studies, a significantly increased neuronal regeneration in group 1 (SETS) compared with all other groups was observed, but with modest (nonsignificant) improvement in electrophysiological and behavioral outcomes. In phase II experiments, the authors discovered that secondary labeling in group 1 was predominantly contributed from the donor (peroneal) pool. Double-labeling counts were dramatically higher in group 2 than in group 1, suggestive of hampered regeneration from the native tibial motor neuron pool across the NIC segment in the presence of SETS. CONCLUSIONS SETS is indeed an effective strategy to enhance axonal regeneration, which is mainly contributed by the donor neuronal pool. Moreover, the presence of a distal SETS coaptation appears to negatively influence neuronal regeneration across the NIC segment. The clinical significance is that SETS should only employ synergistic donors, as the use of antagonistic donors can downgrade recovery.

Biomechanical Evaluation of Knee Joint Laxities and Graft Forces After Anterior Cruciate Ligament Reconstruction by Anteromedial Portal, Outside-In, and Transtibial Techniques

PubMed Central

Sim, Jae Ang; Gadikota, Hemanth R.; Li, Jing-Sheng; Li, Guoan; Gill, Thomas J.

2013-01-01

Background Recently, anatomic anterior cruciate ligament (ACL) reconstruction is emphasized to improve joint laxity and to potentially avert initiation of cartilage degeneration. There is a paucity of information on the efficacy of ACL reconstructions by currently practiced tunnel creation techniques in restoring normal joint laxity. Study Design Controlled laboratory study. Hypothesis Anterior cruciate ligament reconstruction by the anteromedial (AM) portal technique, outside-in (OI) technique, and modified transtibial (TT) technique can equally restore the normal knee joint laxity and ACL forces. Methods Eight fresh-frozen human cadaveric knee specimens were tested using a robotic testing system under an anterior tibial load (134 N) at 0°, 30°, 60°, and 90° of flexion and combined torques (10-N·m valgus and 5-N·m internal tibial torques) at 0° and 30° of flexion. Knee joint kinematics, ACL, and ACL graft forces were measured in each knee specimen under 5 different conditions (ACL-intact knee, ACL-deficient knee, ACL-reconstructed knee by AM portal technique, ACL-reconstructed knee by OI technique, and ACL-reconstructed knee by TT technique). Results Under anterior tibial load, no significant difference was observed between the 3 reconstructions in terms of restoring anterior tibial translation (P > .05). However, none of the 3 ACL reconstruction techniques could completely restore the normal anterior tibial translations (P <.05). Under combined tibial torques, both AM portal and OI techniques closely restored the normal knee anterior tibial translation (P > .05) at 0° of flexion but could not do so at 30° of flexion (P <.05). The ACL reconstruction by the TT technique was unable to restore normal anterior tibial translations at both 0° and 30° of flexion under combined tibial torques (P <.05). Forces experienced by the ACL grafts in the 3 reconstruction techniques were lower than those experienced by normal ACL under both the loading conditions. Conclusion Anterior cruciate ligament reconstructions by AM portal, OI, and modified TT techniques are biomechanically comparable with each other in restoring normal knee joint laxity and in situ ACL forces. Clinical Relevance Anterior cruciate ligament reconstructions by AM portal, OI, and modified TT techniques result in similar knee joint laxities. Technical perils and pearls should be carefully considered before choosing a tunnel creating technique. PMID:21908717

Anterior Cruciate Ligament Reconstruction with Tibial Attachment Preserving Hamstring Graft without Implant on Tibial Side

PubMed Central

Sinha, Skand; Naik, Ananta Kumar; Maheshwari, Mridul; Sandanshiv, Sumedh; Meena, Durgashankar; Arya, Rajendra K

2018-01-01

Background: Tibial attachment preserving hamstring graft could prevent potential problems of free graft in anterior cruciate ligament (ACL) reconstruction such as pull out before graft-tunnel healing or rupture before ligamentization. Different implants have been reportedly used for tibial side fixation with this technique. We investigated short-term outcome of ACL reconstruction (ACLR) with tibial attachment sparing hamstring graft without implant on the tibial side by outside in technique. Materials and Methods: Seventy nine consecutive cases of ACL tear having age of 25.7 ± 6.8 years were included after Institutional Board Approval. All subjects were male. The mean time interval from injury to surgery was of 7.5 ± 6.4 months. Hamstring tendons were harvested with open tendon stripper leaving the tibial insertion intact. The free ends of the tendons were whip stitched, quadrupled, and whip stitched again over the insertion site of hamstring with fiber wire (Arthrex). Single bundle ACLR was done by outside in technique and the femoral tunnel was created with cannulated reamer. The graft was pulled up to the external aperture of femoral tunnel and fixed with interference screw (Arthrex). The scoring was done by Lysholm, Tegner, and KT 1000 by independent observers. All cases were followed up for 2 years. Results: The mean length of quadrupled graft attached to tibia was 127.65 ± 7.5 mm, and the mean width was 7.52 ± 0.78 mm. The mean preoperative Lysholm score of 47.15 ± 9.6, improved to 96.8 ± 2.4 at 1 year. All cases except two returned to the previous level of activity after ACLR. There was no significant difference statistically between preinjury (5.89 ± 0.68) and postoperative (5.87 ± 0.67) Tegner score. The anterior tibial translation (ATT) (KT 1000) improved from 11.44 ± 1.93 mm to 3.59 ± 0.89 mm. The ATT of operated knee returned to nearly the similar value as of the opposite knee (3.47 ± 1.16 mm). The Pivot shift test was negative in all cases. None had a failure of graft till final followup. Conclusion: Attachment sparing hamstring graft without a tibial implant is a simple, cost-effective technique that provides a consistently satisfactory outcome. PMID:29576645

Shin splints - self-care

MedlinePlus

... self-care; Tibial periostitis - self-care; Posterior tibial shin splints - self-care ... Shin splints are an exercise problem. You get shin splints from overloading your leg muscles, tendons or shin ...

Posterior tibial nerve stimulation vs parasacral transcutaneous neuromodulation for overactive bladder in children.

PubMed

Barroso, Ubirajara; Viterbo, Walter; Bittencourt, Joana; Farias, Tiago; Lordêlo, Patrícia

2013-08-01

Parasacral transcutaneous electrical nerve stimulation and posterior tibial nerve stimulation have emerged as effective methods to treat overactive bladder in children. However, to our knowledge no study has compared the 2 methods. We evaluated the results of parasacral transcutaneous electrical nerve stimulation and posterior tibial nerve stimulation in children with overactive bladder. We prospectively studied children with overactive bladder without dysfunctional voiding. Success of treatment was evaluated by visual analogue scale and dysfunctional voiding symptom score, and by level of improvement of each specific symptom. Parasacral transcutaneous electrical nerve stimulation was performed 3 times weekly and posterior tibial nerve stimulation was performed once weekly. A total of 22 consecutive patients were treated with posterior tibial nerve stimulation and 37 with parasacral transcutaneous electrical nerve stimulation. There was no difference between the 2 groups regarding demographic characteristics or types of symptoms. Concerning the evaluation by visual analogue scale, complete resolution of symptoms was seen in 70% of the group undergoing parasacral transcutaneous electrical nerve stimulation and in 9% of the group undergoing posterior tibial nerve stimulation (p = 0.02). When the groups were compared, there was no statistically significant difference (p = 0.55). The frequency of persistence of urgency and diurnal urinary incontinence was nearly double in the group undergoing posterior tibial nerve stimulation. However, this difference was not statistically significant. We found that parasacral transcutaneous electrical nerve stimulation is more effective in resolving overactive bladder symptoms, which matches parental perception. However, there were no statistically significant differences in the evaluation by dysfunctional voiding symptom score, or in complete resolution of urgency or diurnal incontinence. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Tibial component considerations in bicruciate-retaining total knee arthroplasty: A 3D MRI evaluation of proximal tibial anatomy.

PubMed

Saxena, Vishal; Anari, Jason B; Ruutiainen, Alexander T; Voleti, Pramod B; Stephenson, Jason W; Lee, Gwo-Chin

2016-08-01

Restoration of normal anatomy and proper ligament balance are theoretical prerequisites for reproducing physiological kinematics with bicruciate-retaining total knee arthroplasty (TKA). The purpose of this study was to use a 3D MRI technique to evaluate the topography of the proximal tibia and outline considerations in tibial component design for bicruciate-retaining TKA. We identified 100 consecutive patients (50 males and 50 females) between ages 20 and 40 years with knee MRIs without arthritis, dysplasia, ACL tears, or prior knee surgery. A novel 3D MRI protocol coordinating axial, coronal, and sagittal images was used to measure: 1) medial and lateral posterior tibial slopes; 2) medial and lateral coronal slopes; and 3) distance from the anterior tibia to the ACL footprint. There was no overall difference in medial and lateral posterior tibial slopes (5.5° (95% CI 5.0 to 6.0°) vs. 5.4° (95% CI 4.8 to 6.0°), respectively (p=0.80)), but 41 patients had side-to-side differences greater than 3°. The medial coronal slope was greater than the lateral coronal slope (4.6° (95% CI 4.0 to 5.1°) vs. 3.3° (95% CI 2.9 to 3.7°), respectively (p<0.0001)). Females had less clearance between the anterior tibia and ACL footprint than males (10.8mm (95% CI 10.4 to 11.2mm) vs. 13.0mm (95% CI 12.5 to 13.5mm), respectively (p<0.0001)). Due to highly variable proximal tibial topography, a monoblock bicruciate-retaining tibial baseplate may not reproduce normal anatomy in all patients. Level IV - Anatomic research study. Copyright © 2015 Elsevier B.V. All rights reserved.

Favourable rotational alignment outcomes in PSI knee arthroplasty: A Level 1 systematic review and meta-analysis.

PubMed

Mannan, A; Smith, T O

2016-03-01

Implant malposition in total knee arthroplasty (TKA) often results in unsatisfactory outcomes. Rotational malalignment leads to impaired patellar tracking, stability and joint biomechanics. Patient-specific instrumentation aims to improve three-dimensional implant positioning while reducing overall costs of instrumentation. A PRISMA compliant search of all relevant literature between 2000 and 2014 was performed. The primary outcome of interest was deviation from a neutral femoral and tibial axial alignment of patient-specific instrumentation (PSI) vs conventional instrumentation. Femoral rotation was measured with reference to the transepicondylar axis. Tibial rotation was reported with reference to the anterior tibial tuberosity and a "best fit" with the anterior tibial cortex. Six randomised studies met the inclusion criteria reporting on a total of 444 knees. Computed tomography (CT) based PSI systems were used exclusively in three studies, and two further studies in association with magnetic resonance imaging (MRI). MRI was used exclusively in one study. Mean femoral rotation in the conventional group was: -1.7 to 1.6° (vs -1.7 to 1° in the PSI group). Meta-analysis demonstrated a significant treatment effect favouring PSI with increased accuracy in "three-degree outliers" with femoral rotation: Z=2.07, P=0.04. A single study reported tibial rotational outcomes with no significant difference demonstrated in conventional instrumentation vs PSI. This Level 1 meta-analysis demonstrates favourable femoral rotational alignment outcomes in PSI knee arthroplasty. Only limited data is available for tibial rotational outcomes. Further studies with standardised "gold-standard" measurement criteria are required to clarify tibial rotational outcomes in PSI TKA. 1. Copyright © 2015 Elsevier B.V. All rights reserved.

In vivo tibial stiffness is maintained by whole bone morphology and cross-sectional geometry in growing female mice

PubMed Central

Main, Russell P.; Lynch, Maureen E.; van der Meulen, Marjolein C.H.

2010-01-01

Whole bone morphology, cortical geometry, and tissue material properties modulate skeletal stresses and strains that in turn influence skeletal physiology and remodeling. Understanding how bone stiffness, the relationship between applied load and tissue strain, is regulated by developmental changes in bone structure and tissue material properties is important in implementing biophysical strategies for promoting healthy bone growth and preventing bone loss. The goal of this study was to relate developmental patterns of in vivo whole bone stiffness to whole bone morphology, cross-sectional geometry, and tissue properties using a mouse axial loading model. We measured in vivo tibial stiffness in three age groups (6wks, 10wks, 16wks old) of female C57Bl/6 mice during cyclic tibial compression. Tibial stiffness was then related to cortical geometry, longitudinal bone curvature, and tissue mineral density using microcomputed tomography (microCT). Tibial stiffness and the stresses induced by axial compression were generally maintained from 6 to 16wks of age. Growth-related increases in cortical cross-sectional geometry and longitudinal bone curvature had counteracting effects on induced bone stresses and, therefore, maintained tibial stiffness similarly with growth. Tissue mineral density increased slightly from 6 to 16wks of age, and although the effects of this increase on tibial stiffness were not directly measured, its role in the modulation of whole bone stiffness was likely minor over the age range examined. Thus, whole bone morphology, as characterized by longitudinal curvature, along with cortical geometry, plays an important role in modulating bone stiffness during development and should be considered when evaluating and designing in vivo loading studies and biophysical skeletal therapies. PMID:20673665

Are undesirable contact kinematics minimized after kinematically aligned total knee arthroplasty? An intersurgeon analysis of consecutive patients.

PubMed

Howell, Stephen M; Hodapp, Esther E; Vernace, Joseph V; Hull, Maury L; Meade, Thomas D

2013-10-01

Tibiofemoral contact kinematics or knee implant motions have a direct influence on patient function and implant longevity and should be evaluated for any new alignment technique such as kinematically aligned total knee arthroplasty (TKA). Edge loading of the tibial liner and external rotation (reverse of normal) and adduction of the tibial component on the femoral component are undesirable contact kinematics that should be minimized. Accordingly, this study determined whether the overall prevalence of undesirable contact kinematics during standing, mid kneeling near 90 degrees and full kneeling with kinematically aligned TKA are minimal and not different between groups of consecutive patients treated by different surgeons. Three surgeons were asked to perform cemented, kinematically aligned TKA with patient-specific guides in a consecutive series of patients with their preferred cruciate-retaining (CR) implant. In vivo tibiofemoral contact positions were obtained using a 3- to 2-dimensional image registration technique in 69 subjects (Vanguard CR-TKA N = 22, and Triathlon CR-TKA N = 47). Anterior or posterior edge loading of the tibial liner was not observed. The overall prevalence of external rotation of the tibial component on the femoral component of 6 % was low and not different between surgeons (n.s.). The overall prevalence of adduction of the tibial component on the femoral component of 4 % was low and not different between surgeons (n.s.). Kinematically aligned TKA minimized the undesirable contact kinematics of edge loading of the tibial liner, and external rotation and adduction of the tibial component on the femoral component during standing and kneeling, which suggests an optimistic prognosis for durable long-term function. III.

Balanced Flexion and Extension Gaps Are Not Always of Equal Size.

PubMed

Kinsey, Tracy L; Mahoney, Ormonde M

2018-04-01

It has been widely accepted in total knee arthroplasty (TKA) that flexion and extension gaps in the disarticulated knee during surgery should be equalized. We hypothesized that tensioning during assessment of the flexion gap can induce temporary widening of the gap due to posterior tibial translation. We aimed to describe posterior tibial translation at flexion gap (90°) assessments and assess the correlation of tibial translation with laxity (flexion space increase) using constrained and non-constrained inserts. Imageless navigation was used to measure flexion angle, tibial position relative to the femoral axis, and lateral/medial laxity in 30 patients undergoing primary TKA. Trialing was conducted using posteriorly stabilized and cruciate retaining trials of the same size to elucidate the association of posterior tibial translation with changes in joint capsule laxity at 90° knee flexion. All patients demonstrated posterior tibial translation during flexion gap assessment relative to their subsequent final implantation [mean ± standard deviation (range), 11.3 ± 4.4 (4-21) mm]. Positive linear correlation [r = 0.69, 95% confidence interval (CI) 0.44-0.84, P ≤ .001] was demonstrated between translations [8.7 ± 2.4 (3-13) mm] and laxity changes [2.9° ± 2.0° (-0.7° to 7.4°)] at 90° of flexion. Posterior tibial translation can cause artifactual widening of the flexion gap during gap balancing in posteriorly stabilized TKA, which can be of sufficient magnitude to alter femoral component size selection for some patients. Recognition and management of these intra-operative dynamics for optimal kinematics could be feasible with the advent of robotic applications. Copyright © 2017 Elsevier Inc. All rights reserved.

High resolution ultrasonography of the tibial nerve in diabetic peripheral neuropathy.

PubMed

Singh, Kunwarpal; Gupta, Kamlesh; Kaur, Sukhdeep

2017-12-01

High-resolution ultrasonography of the tibial nerve is a fast and non invasive tool for diagnosis of diabetic peripheral neuropathy. Our study was aimed at finding out the correlation of the cross sectional area and maximum thickness of nerve fascicles of the tibial nerve with the presence and severity of diabetic peripheral neuropathy. 75 patients with type 2 diabetes mellitus clinically diagnosed with diabetic peripheral neuropathy were analysed, and the severity of neuropathy was determined using the Toronto Clinical Neuropathy Score. 58 diabetic patients with no clinical suspicion of diabetic peripheral neuropathy and 75 healthy non-diabetic subjects were taken as controls. The cross sectional area and maximum thickness of nerve fascicles of the tibial nerves were calculated 3 cm cranial to the medial malleolus in both lower limbs. The mean cross sectional area (22.63 +/- 2.66 mm 2 ) and maximum thickness of nerve fascicles (0.70 mm) of the tibial nerves in patients with diabetic peripheral neuropathy compared with both control groups was significantly larger, and statistically significant correlation was found with the Toronto Clinical Neuropathy Score ( p < 0.001). The diabetic patients with no signs of peripheral neuropathy had a larger mean cross sectional area (14.40 +/- 1.72 mm 2 ) and maximum thickness of nerve fascicles of the tibial nerve (0.40 mm) than healthy non-diabetic subjects (12.42 +/- 1.01 mm 2 and 0.30 mm respectively). The cross sectional area and maximum thickness of nerve fascicles of the tibial nerve is larger in diabetic patients with or without peripheral neuropathy than in healthy control subjects, and ultrasonography can be used as a good screening tool in these patients.

Radiographic Investigation of the Distal Extension of Fractures Into the Articular Surface of the Tibia (The RIDEFAST Study).

PubMed

Marchand, Lucas S; Rane, Ajinkya A; Working, Zachary M; Jacobson, Lance G; Kubiak, Erik N; Higgins, Thomas F; Rothberg, David L

2017-12-01

To determine whether radiographic measurements are predictive of involvement of the distal tibia articular surface in tibial shaft fractures. Retrospective review. Academic Level-I trauma hospital. Two-hundred seventeen patients with tibial shaft fractures distal to the isthmus (OTA/AO: 42-A1-3; 42-B1-3; 42-C1-3; and 43-A1-3). Analysis of anteroposterior (AP) and lateral radiographs. The following parameters were measured: (1) angle between the predominant fracture line and the plane of the tibial plafond (α-angle), (2) length of the shaft fracture, (3) distance from the most inferior extent of the shaft fracture to the tibial plafond (DTP), (4) width of the tibial plafond, (5) width of the tibial isthmus, (6) ratio of fracture length to DTP (FTP), and (7) fibular fracture distance. Distal intra-articular involvement (DIA). A total of 217 patients were identified, 56 (26%) with DIA. The FTP ratio as measured on both the AP (odds ratio: 8.20, confidence interval, 4.26-17.22, P < 0.0001) and lateral radiographs (10.00, 4.78-23.23, <0.0001) was the most effective screening measurement for DIA. AP and lateral FTP ratios of 0.224 and 0.255, respectively, achieved a negative predictive value of 100%, eliminating the need for computed tomography in 16%-23% of injuries. Involvement of the distal articular surface in patients with distal tibial shaft fractures is significantly associated with fracture geometry and pattern. The FTP ratio may be used as an effective screening tool to rule out of intra-articular involvement. Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Chronic shin splints. Classification and management of medial tibial stress syndrome.

PubMed

Detmer, D E

1986-01-01

A clinical classification and treatment programme has been developed for chronic medial tibial stress syndrome. Medial tibial stress syndrome has been reported to be either tibial stress fracture or microfracture, tibial periostitis, or distal deep posterior chronic compartment syndrome. Three chronic types exist and may coexist: Type I (tibial microfracture, bone stress reaction or cortical fracture); type II (periostalgia from chronic avulsion of the periosteum at the periosteal-fascial junction); and type III (chronic compartment syndrome syndrome). Type I disease is treated nonoperatively. Operations for resistant types II and III medial tibial stress syndrome were performed in 41 patients. Bilaterality was common (type II, 50% type III, 88%). Seven had coexistent type II/III; one had type I/II. Preoperative symptoms averaged 24 months in type II, 6 months in type III, and 33 months in types II/III. Mean age was 22 years (15 to 51). Resting compartment pressures were normal in type II (mean 12 mm Hg) and elevated in type III and type II/III (mean 23 mm Hg). Type II and type II/III patients received fasciotomy plus periosteal cauterisation. Type III patients had fasciotomy only. All procedures were performed on an outpatient basis using local anaesthesia. Follow up was complete and averaged 6 months (2 to 14 months). Improved performance was as follows: type II, 93%, type III, 100%; type II/III, 86%. Complete cures were as follows: type II, 78%; type III, 75%; and type II/III, 57%. This experience suggests that with precise diagnosis and treatment involving minimal risk and cost the athlete has a reasonable chance of return to full activity.

Reliability of frames of reference used for tibial component rotation in total knee arthroplasty.

PubMed

Page, Stephen R; Deakin, Angela H; Payne, Anthony P; Picard, Frederic

2011-01-01

This study evaluated seven different frames of reference used for tibial component rotation in total knee arthroplasty (TKA) to determine which ones showed good reliability between bone specimens. An optoelectronic system based around a computer-assisted surgical navigation system was used to measure and locate 34 individual anatomical landmarks on 40 tibias. Each particular frame of reference was reconstructed from a group of data points taken from the surface of each bone. The transverse axis was used as the baseline to which the other axes were compared, and the differences in angular rotation between the other six reference frames and the transverse axis were calculated. There was high variability in the tibial rotational alignment associated with all frames of reference. Of the references widely used in current TKA procedures, the tibial tuberosity axis and the anterior condylar axis had lower standard deviations (6.1° and 7.3°, respectively) than the transmalleolar axis and the posterior condylar axis (9.3° for both). In conclusion, we found high variability in the frames of reference used for tibial rotation alignment. However, the anterior condylar axis and transverse axis may warrant further tests with the use of navigation. Combining different frames of reference such as the tibial tuberosity axis, anterior condylar axis and transverse axis may reduce the range of errors found in all of these measurements.

The distance from the extramedullary cutting guide rod to the skin surface as a reference guide for the tibial slope in total knee arthroplasty.

PubMed

Tsukeoka, Tadashi; Tsuneizumi, Yoshikazu

2016-03-01

Although sagittal tibial alignment in total knee arthroplasty (TKA) is important, no landmarks exist to achieve a reproducible slope. The purpose of this study was to evaluate the clinical usefulness of the distance from the guide rod to the skin surface for the tibial slope in TKA. Computer simulation studies were performed on 100 consecutive knees scheduled for TKA. The angle between the line connecting the most anterior point of the predicted tibial cut surface and the skin surface 20 cm distal to the predicted cut surface (Line S) and the mechanical axis (MA) of the tibia in the sagittal plane was measured. The mean (±SD) absolute angle difference between the Line S and the MA was 0.9°±0.7°. The Line S was almost parallel to the MA in the sagittal plane (95% and 99% within two degrees and three degrees of deviation from MA, respectively). The guide rod orientation is a surrogate for the tibial cut slope because the targeted posterior slope is usually built into the cutting block and ensuring the rod is parallel to the MA in the sagittal plane is recommended. Therefore the distance between the skin surface and the rod can be a useful guide for the tibial slope. II. Copyright © 2015 Elsevier B.V. All rights reserved.

The role of fixation and bone quality on the mechanical stability of tibial knee components.

PubMed

Lee, R W; Volz, R G; Sheridan, D C

1991-12-01

Tibial component loosening remains one of the major causes of failure of cemented and noncemented total knee arthroplasties. In this study, the authors identified the role of implant design, method of fixation, and bone density as it related to implant stability. The physical properties of "good" and "bad" bone were simulated using a "good" and "bad" foam model of the proximal tibia, fabricated in the laboratory from DARO RF-100 foam. A generic tibial component permitting various fixation designs was implanted into "good" and "bad" variable density foam tibial models in both cemented and noncemented modes. The mechanical stability of the implants was determined using a Materials Testing Machine by the application of an eccentrically applied cyclic load. The micromotion (subsidence and lift-off) of the tibial implants was recorded using two Linear Variable Differential Transformers. Statistically significant differences in implant stability were recorded as a function of fixation method. The most rigid implant fixation was achieved using four peripherally placed, 6.5-mm cancellous screws. The addition of a central stem added stability only in the case of "poor" quality foam. The mechanical stability of noncemented implants related directly to the density of the foam. Implant stability was greatly enhanced in "poor" quality foam by the use of cement. The method of implant fixation and bone density are critical determinants to tibial implant stability.

Landing strategies focusing on the control of tibial rotation in the initial contact period of one-leg forward hops.

PubMed

Chen, W-L; Chen, Y-T; Huang, S-Y; Yang, C-Y; Wu, C-D; Chang, C-W

2017-08-01

Anterior cruciate ligament (ACL) reconstruction (ACLR) surgeries successfully restore anterior tibial translation but not tibial rotation. This study aimed to explore landing strategies focusing on the control of tibial rotation at landing when the ACL is most vulnerable. Three groups of male subjects (50 ACLRs, 26 basketball players, and 31 controls) participated in one-leg forward hop tests for determining the tibial rotatory landing strategies adopted during the initial landing phase. The differences in knee kinematics and muscle activities between internal and external tibial rotatory (ITR, ETR) landing strategies were examined. A higher proportion of basketball players (34.6%) were found to adopt ITR strategies (controls: 6.5%), exhibiting significantly greater hopping distance and knee strength. After adjusting for hopping distance, subjects adopting ITR strategies were found to hop faster with straighter knees at foot contact and with greater ITR and less knee adduction angular displacement during the initial landing phase. However, significantly greater angular displacement in knee flexion, greater medial hamstring activities, and greater co-contraction index of hamstrings and medial knee muscles were also found during initial landing. Our results support the importance of the recruitments of medial hamstrings or the local co-contraction in assisting the rotatory control of the knee during initial landing for avoiding ACL injuries. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

High energy focused shock wave therapy accelerates bone healing. A blinded, prospective, randomized canine clinical trial.

PubMed

Kieves, N R; MacKay, C S; Adducci, K; Rao, S; Goh, C; Palmer, R H; Duerr, F M

2015-01-01

To evaluate the influence of shock wave therapy (SWT) on radiographic evidence of bone healing after tibial plateau leveling osteotomy (TPLO). Healthy dogs between two to nine years of age that underwent TPLO were randomly assigned to receive either electro-hydraulic SWT (1,000 shocks) or sham treatment (SHAM). Treatment or SHAM was administered to the osteotomy site immediately postoperatively and two weeks postoperatively. Three blinded radiologists evaluated orthogonal radiographs performed eight weeks postoperatively with both a 5-point and a 10-point bone healing scale. Linear regression analysis was used to compare median healing scores between groups. Forty-two dogs (50 stifles) were included in the statistical analysis. No major complications were observed and all osteotomies healed uneventfully. The median healing scores were significantly higher at eight weeks postoperatively for the SWT group compared to the SHAM group for the 10-point (p <0.0002) and 5-point scoring systems (p <0.0001). Shock wave therapy applied immediately and two weeks postoperatively led to more advanced bone healing at the eight week time point in this study population. The results of this study support the use of electro-hydraulic SWT as a means of accelerating acute bone healing of canine osteotomies. Additional studies are needed to evaluate its use for acceleration of bone healing following fracture, or with delayed union.

Quantitative Comparison of the Microscopic Anatomy of the Human ACL Femoral and Tibial Entheses

PubMed Central

Beaulieu, Mélanie L.; Carey, Grace E.; Schlecht, Stephen H.; Wojtys, Edward M.; Ashton-Miller, James A.

2015-01-01

The femoral enthesis of the human anterior cruciate ligament (ACL) is known to be more susceptible to injury than the tibial enthesis. To determine whether anatomic differences might help explain this difference, we quantified the microscopic appearance of both entheses in 15 unembalmed knee specimens using light microscopy, toluidine blue stain and image analysis. The amount of calcified fibrocartilage and uncalcified fibrocartilage, and the ligament entheseal attachment angle were then compared between the femoral and tibial entheses via linear mixed-effects models. The results showed marked differences in anatomy between the two entheses. The femoral enthesis exhibited a 3.9-fold more acute ligament attachment angle than the tibial enthesis (p < 0.001), a 43% greater calcified fibrocartilage tissue area (p < 0.001), and a 226% greater uncalcified fibrocartilage depth (p < 0.001), with the latter differences being particularly pronounced in the central region. We conclude that the ACL femoral enthesis has more fibrocartilage and a more acute ligament attachment angle than the tibial enthesis, which provides insight into why it is more vulnerable to failure. PMID:26134706

Biomechanical study of the tibia in knee replacement revision.

PubMed

Quílez, M P; Pérez, M A; Seral-García, B

2015-01-01

The best management of severe bone defects following total knee replacement is still controversial. Metal augments, tantalum cones and porous tibial sleeves could help the surgeon to manage any type of bone loss, providing a stable and durable knee joint reconstruction. Five different types of prostheses have been analysed: one prosthesis with straight stem; two prostheses with offset stem, with and without supplement, and two prostheses with sleeves, with and without stem. The purpose of this study is to report a finite element study of revision knee tibial implants. The main objective was to analyse the tibial bone density changes and Von Misses tension changes following different tibial implant designs. In all cases, the bone density decreases in the proximal epiphysis and medullary channels, with a bone density increase also being predicted in the diaphysis and at the bone around the stems tips. The highest value of Von Misses stress has been obtained for the straight tibial stem, and the lowest for the stemless metaphyseal sleeves prosthesis. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.

On the longitudinal distribution of electric field in the acceleration zones of plasma accelerators and thrusters with closed electron drift

NASA Astrophysics Data System (ADS)

Kim, V. P.

2017-04-01

The long-term experience in controlling the electric field distribution in the discharge gaps of plasma accelerators and thrusters with closed electron drift and the key ideas determining the concepts of these devices and tendencies of their development are analyzed. It is shown that an electrostatic mechanism of ion acceleration in plasma by an uncompensated space charge of the cloud of magnetized electrons "kept" to the magnetic field takes place in the acceleration zones and that the electric field distribution can be controlled by varying the magnetic field in the discharge gap. The role played by the space charge makes the mechanism of ion acceleration in this type of thrusters is fundamentally different from the acceleration mechanism operating in purely electrostatic thrusters.

"Shin splint" syndrome and tibial stress fracture in the same patient diagnosed by means of (99m)Tc-HMDP SPECT/CT.

PubMed

Vicente, Justo Serrano; Grande, Maria Luz Domínguez; Torre, Jose Rafael Infante; Madrid, Juan Ignacio Rayo; Barquero, Carmen Durán; Bernardo, Lucía García; Sánchez, Román Sánchez

2013-04-01

We show a patient who presented leg pain triggered by intense exercise. The most likely diagnosis was a possible tibial stress fracture or a "shin splint" syndrome (soleus enthesopathy). We performed a bone scintigraphy including SPECT/CT that revealed the presence of the two concomitant pathologies. SPECT/CT identified the hot spot superimposed with bone lesion in the tibial stress fracture and only remodeling activity without evidence of cortical lesions in the enthesopathy processes.

The medial tibial stress syndrome. A cause of shin splints.

PubMed

Mubarak, S J; Gould, R N; Lee, Y F; Schmidt, D A; Hargens, A R

1982-01-01

The medial tibial stress syndrome is a symptom complex seen in athletes who complain of exercise-induced pain along the distal posterior-medial aspect of the tibia. Intramuscular pressures within the posterior compartments of the leg were measured in 12 patients with this disorder. These pressures were not elevated and therefore this syndrome is a not a compartment syndrome. Available information suggests that the medial tibial stress syndrome most likely represents a periostitis at this location of the leg.

Technique tip: use of anterior cruciate ligament jig for hindfoot fusion by calcanio-talo-tibial nail.

PubMed

Haque, Syed; Sarkar, Jay

2012-08-01

The use of intramedullary nail fixation for tibio-talo-calcaneal fusion is gaining popularity. There is chance of failure of procedure following faulty operative technique specially alignment. The article describes a useful application of tibial tunnel jig in inserting the calcanio-talo-tibial guide wire. There is precision of few millimeters in the exit point of guide wire on talus. The authors believe that this helps in better positioning of nail and hence better alignment and better operative outcome.

Improving Soldier Recovery from Catastrophic Bone Injuries: Developing an Animal Model for Standarizing the Bone Reparative Potential of Emerging Progenitor Cell Therapies

DTIC Science & Technology

2008-08-01

To better understand the cellular basis of a long bone defect, we have utilized the GFP reporters in the closed tibial fracture. The surprise finding...callus. In the coming year we will apply the information learned from the calvarial defect to a non-union extension of the tibial fracture model...initiated a comprehensive examination of the tibial fracture model in mice bearing GFP reporters of lineage progression. This project has been assumed

Shock Wave-Stimulated Periosteum for Cartilage Repair

DTIC Science & Technology

2012-12-01

inserted into the tibial periosteum of 6 animals to measure the actual shock waveform in the tissue for two ESW doses (energy densities). In 12 goats... tibial periosteum stimulated by one of the 2 doses of ESWs (n=6) will be harvested, 4 days post-treatment, as an autograft for implantation into one 1...locations of sensor away from the head of the ESW device. 1.b. Insert a pressure sensor into the periosteum of the right proximal tibial of6 goats to

Trajectory of cartilage loss within 4 years of knee replacement--a nested case-control study from the osteoarthritis initiative.

PubMed

Eckstein, F; Boudreau, R M; Wang, Z; Hannon, M J; Wirth, W; Cotofana, S; Guermazi, A; Roemer, F; Nevitt, M; John, M R; Ladel, C; Sharma, L; Hunter, D J; Kwoh, C K

2014-10-01

Knee replacement (KR) represents a clinically important endpoint of knee osteoarthritis (KOA). Here we examine the 4-year trajectory of femoro-tibial cartilage thickness loss prior to KR vs non-replaced controls. A nested case-control study was performed in Osteoarthritis Initiative (OAI) participants: Cases with KR between 12 and 60 month (M) follow-up were each matched with one control (without KR through 60M) by age, sex, and baseline radiographic stage. Femoro-tibial cartilage thickness was measured quantitatively using magnetic resonance imaging (MRI) at the annual visit prior to KR occurrence (T0), and at 1-4 years prior to T0 (T-1 to T-4). Cartilage loss between cases and controls was compared using paired t-tests and conditional logistic regression. One hundred and eighty-nine knees of 164 OAI participants [55% women; age 64 ± 8.7; body mass index (BMI) 29 ± 4.5] had KR and longitudinal cartilage data. Comparison of annualized slopes of change across all time points revealed greater loss in the central medial tibia (primary outcome) in KRs than in controls [94 ± 137 vs 55 ± 104 μm; P = 0.0017 (paired t); odds ratio (OR) 1.36 (95% confidence interval (CI): 1.08-1.70)]. The discrimination was stronger for T-2 → T0 [OR 1.61 (1.33-1.95), n = 127] than for T-1 → T0, and was not statistically significant for intervals prior to T-2 [i.e., T-4 → T-2, OR 0.97 (0.67-1.41), n = 60]. Results were similar for total medial femoro-tibial cartilage loss (secondary outcome), and when adjusting for pain and BMI. In knees with subsequent replacement, cartilage loss accelerates in the 2 years, and particularly in the year prior to surgery, compared with controls. Whether slowing this cartilage loss can delay KR remains to be determined. Copyright © 2014 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Influence of the ambient acceleration field upon acute acceleration tolerance in chickens

NASA Technical Reports Server (NTRS)

Smith, A. H.; Spangler, W. L.; Rhode, E. A.; Burton, R. R.

1979-01-01

The paper measured the acceleration tolerance of domestic fowl (Rhode Island Red cocks), acutely exposed to a 6 Gz field, as the time over which a normal heart rate can be maintained. This period of circulatory adjustment ends abruptly with pronounced bradycardia. For chickens which previously have been physiologically adapted to 2.5 -G field, the acute acceleration tolerance is greatly increased. The influence of the ambient acceleration field on the adjustment of the circulatory system appears to be a general phenomenon.

Posterior stability in fixed-bearing versus mobile-bearing total knee replacement: a radiological comparison of two implants.

PubMed

Siebold, R; Louisia, S; Canty, J; Bartlett, R J

2007-02-01

Posterior tibial translation in total knee replacement (TKR) could be one major factor for PE wear, delamination and loosening of the tibial component due to increased shear forces and component-to-bone interface stress. The aim of this study was to assess the posterior stability of two different designs of posterior cruciate ligament (PCL) substituting TKR. In this non-randomised consecutive study 43 patients underwent TKR for primary osteoarthritis. Twenty-six patients in group FB received a deep-dished fixed-bearing Duracon TKR (Howmedica, Rutherford, NJ, USA) and 17 patients in group MB a deep-dished rotating mobile-bearing Duracon TKR. In both groups the PCL was resected. All patients had pre- and postoperative kneeling stress radiographs and were clinically evaluated with the Knee Society Score. Posterior tibial translation was measured by tracing a line along the posterior tibial cortex in relationship to the posterior edge of Blumensaat's line. The average follow-up was 13 months for group FB and 11 months for group MB. Both groups demonstrated a statistical significant increase of the mean posterior tibial translation on kneeling stress X-ray of 4.1 mm (group FB) (P < 0.001) and of 6.6 mm (group MB) (P < 0.001) compared to pre-operative. Group MB showed a significant higher posterior draw (P < 0.008). Clinical assessment using the Knee Society Score showed comparable short-term results. The deep-dished fixed-bearing TKR as well as the deep-dished rotating mobile-bearing TKR demonstrated significant posterior tibial translation on kneeling stress X-ray. It remains to be determined what amount of joint play is optimal for clinical function and to minimise shear forces and PE wear. Moreover the amount of posterior tibial translation was significantly higher with the mobile-bearing insert, which could be directly related to the asymmetric rotational mobility of the tibial insert. A long-term follow-up is necessary to investigate whether our findings correlate with the survival-rate of these specific implants.

Tibial slope correction combined with second revision ACL produces good knee stability and prevents graft rupture.

PubMed

Dejour, David; Saffarini, Mo; Demey, Guillaume; Baverel, Laurent

2015-10-01

Revision ACL reconstruction requires careful analysis of failure causes particularly in cases of two previous graft ruptures. Intrinsic factors as excessive tibial slope or narrow femoral notch increase failure risks but are rarely addressed in revision surgery. The authors report outcomes, at minimum follow-up of 2 years, for second revision ACL reconstructions combined with tibial deflexion osteotomy for correction of excessive slope (>12°). Nine patients that underwent second revision ACL reconstruction combined with tibial deflexion osteotomy were retrospectively studied. The mean age was 30.3 ± 4.4 years (median 28; range 26-37), and mean follow-up was 4.0 ± 2.0 years (median 3.6; range 2.0-7.6). Autografts were harvested from the quadriceps tendon (n = 8) or hamstrings (n = 1), and tibial osteotomy was done by anterior closing wedge, without detachment of the patellar tendon, to obtain a slope of 3° to 5°. All patients had fused osteotomies, stable knees, and there were no intraoperative or postoperative complications. The mean posterior tibial slope decreased from 13.2° ± 2.6° (median 13°; range 12°-18°) preoperatively to 4.4° ± 2.3° (median 4°; range 2°-8°) postoperatively. The mean Lysholm score was 73.8 ± 5.8 (median 74; range 65-82), and the IKDC-SKF was 71.6 ± 6.1 (median 72.8; range 62.2-78.5). The satisfactory results of second revision ACL reconstruction combined with tibial deflexion osteotomy at minimum follow-up of 2 years suggest that tibia slope correction protects reconstructed ACL from fatigue failure in this study. The authors stress the importance of careful analysis failure causes prior to revision ACL reconstruction, and recommend correction of tibial slope if it exceeds 12°, to reduce the risks of graft retear. III.

Significant effect of the posterior tibial slope and medial/lateral ligament balance on knee flexion in total knee arthroplasty.

PubMed

Fujimoto, Eisaku; Sasashige, Yoshiaki; Masuda, Yasuji; Hisatome, Takashi; Eguchi, Akio; Masuda, Tetsuo; Sawa, Mikiya; Nagata, Yoshinori

2013-12-01

The intra-operative femorotibial joint gap and ligament balance, the predictors affecting these gaps and their balances, as well as the postoperative knee flexion, were examined. These factors were assessed radiographically after a posterior cruciate-retaining total knee arthroplasty (TKA). The posterior condylar offset and posterior tibial slope have been reported as the most important intra-operative factors affecting cruciate-retaining-type TKAs. The joint gap and balance have not been investigated in assessments of the posterior condylar offset and the posterior tibial slope. The femorotibial gap and medial/lateral ligament balance were measured with an offset-type tensor. The femorotibial gaps were measured at 0°, 45°, 90° and 135° of knee flexion, and various gap changes were calculated at 0°-90° and 0°-135°. Cruciate-retaining-type arthroplasties were performed in 98 knees with varus osteoarthritis. The 0°-90° femorotibial gap change was strongly affected by the posterior condylar offset value (postoperative posterior condylar offset subtracted by the preoperative posterior condylar offset). The 0°-135° femorotibial gap change was significantly correlated with the posterior tibial slope and the 135° medial/lateral ligament balance. The postoperative flexion angle was positively correlated with the preoperative flexion angle, γ angle and the posterior tibial slope. Multiple-regression analysis demonstrated that the preoperative flexion angle, γ angle, posterior tibial slope and 90° medial/lateral ligament balance were significant independent factors for the postoperative knee flexion angle. The flexion angle change (postoperative flexion angle subtracted by the preoperative flexion angle) was also strongly correlated with the preoperative flexion angle, posterior tibial slope and 90° medial/lateral ligament balance. The postoperative flexion angle is affected by multiple factors, especially in cruciate-retaining-type TKAs. However, it is important to pay attention not only to the posterior tibial slope, but also to the flexion medial/lateral ligament balance during surgery. A cruciate-retaining-type TKA has the potential to achieve both stability and a wide range of motion and to improve the patients' activities of daily living.

Ipsilateral intact fibula as a predictor of tibial plafond fracture pattern and severity.

PubMed

Luk, Pamela C; Charlton, Timothy P; Lee, Jackson; Thordarson, David B

2013-10-01

The objective of this study was to determine whether there is a difference in fracture pattern and severity of comminution between tibial plafond fractures with and without associated fibular fractures using computed tomography (CT). We hypothesized that the presence of an intact fibula was predictive of increased tibial plafond fracture severity. This was a case control, radiographic review performed at a single level I university trauma center. Between November 2007 and July 2011, 104 patients with 107 operatively treated tibial pilon fractures and preoperative CT scans were identified: 70 patients with 71 tibial plafond fractures had associated fibular fractures, and 34 patients with 36 tibial plafond fractures had intact fibulas. Four criteria were compared between the 2 groups: AO/OTA classification of distal tibia fractures, Topliss coronal and sagittal fracture pattern classification, plafond region of greatest comminution, and degree of proximal extension of fracture line. The intact fibula group had greater percentages of AO/OTA classification B2 type (5.5 vs 0, P = .046) and B3 type (52.8 vs 28.2, P = .013). Conversely, the percentage of AO/OTA classification C3 type was greater in the fractured fibula group (53.5 vs 30.6, P = .025). Evaluation using the Topliss sagittal and coronal classifications revealed no difference between the 2 groups (P = .226). Central and lateral regions of the plafond were the most common areas of comminution in fractured fibula pilons (32% and 31%, respectively). The lateral region of the plafond was the most common area of comminution in intact fibula pilon fractures (42%). There was no statistically significant difference (P = .71) in degree of proximal extension of fracture line between the 2 groups. Tibial plafond fractures with intact fibulas were more commonly associated with AO/OTA classification B-type patterns, whereas those with fractured fibulas were more commonly associated with C-type patterns. An intact fibula may be predictive of less comminution of the plafond. The lateral and central regions of the plafond were the most common areas of comminution in tibial plafond fractures, regardless of fibular status. Level III, case control study.

A TE-mode accelerator

NASA Astrophysics Data System (ADS)

Takeuchi, S.; Sakai, K.; Matsumoto, M.; Sugihara, R.

1987-04-01

An accelerator is proposed in which a TE-mode wave is used to drive charged particles in contrast to the usual linear accelerators in which longitudinal electric fields or TM-mode waves are supposed to be utilized. The principle of the acceleration is based on the V(p) x B acceleration of a dynamo force acceleration, in which a charged particle trapped in a transverse wave feels a constant electric field (Faraday induction field) and subsequently is accelerated when an appropriate magnetic field is externally applied in the direction perpendicular to the wave propagation. A pair of dielectric plates is used to produce a slow TE mode. The conditions of the particle trapping the stabilization of the particle orbit are discussed.

Geometry of the Valgus Knee: Contradicting the Dogma of a Femoral-Based Deformity.

PubMed

Eberbach, Helge; Mehl, Julian; Feucht, Matthias J; Bode, Gerrit; Südkamp, Norbert P; Niemeyer, Philipp

2017-03-01

Realignment osteotomies of valgus knee deformities are usually performed at the distal femur, as valgus alignment is considered to be a femoral-based deformity. This dogma, however, has not been proven in a large patient population. Valgus malalignment may also be caused by a tibial deformity or a combined tibial and femoral deformity. The purposes of this study were (1) to analyze the coronal geometry of patients with valgus malalignment and identify the location of the underlying deformity and (2) to investigate the proportion of cases that require realignment osteotomy at the tibia, the femur, or both locations to avoid an oblique joint line. Cross-sectional study; Level of evidence, 3. The analysis included 420 standing full-leg radiographs of patients with valgus malalignment (mechanical femorotibial angle [mFTA], ≥4°). A systematic analysis of the coronal leg geometry was performed including the mFTA, mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), and joint-line convergence angle (JLCA). The localization of the deformity was determined according to the malalignment test described by Paley, and patients were assigned to 1 of 4 groups: femoral-based valgus deformity, tibial-based valgus deformity, femoral- and tibial-based valgus deformity, or intra-articular/ligamentary-based valgus deformity. Subsequently, the ideal osteotomy site was identified with the goal of a postoperative change of the joint line of two different maximum values, ±2° and ±4°, from its physiological varus position of 3°. Measurements of the coronal alignment revealed a mean (±SD) mFTA of 7.4° ± 4.3° (range, 4°-28.2°). The mean mLDFA and mean mMPTA were 84.8° ± 2.4° and 90.9° ± 2.6°, respectively. The mean JLCA was 1.2° ± 3.1°. The majority (41.0%) of valgus deformities were tibial based, 23.6% were femoral based, 26.9% were femoral and tibial based, and 8.6% were intra-articular/ligamentary based. To achieve a straight-leg axis and an anatomic postoperative joint line with a tolerance of ±4°, the ideal site of a corrective osteotomy was tibial in 55.2% of cases and femoral in 19.5% of cases. A double-level osteotomy would be necessary in 25.2% of cases. With a tolerance of ±2°, the ideal osteotomy site was the proximal tibia in 41.0% of cases and the distal femur in 13.6% of cases; a double-level osteotomy would be necessary in 45.5% of cases. In contrast to the widespread belief that valgus malalignment is usually caused by a femoral deformity, this study found that valgus malalignment was attributable to tibial deformity in the majority of patients. In addition, a combined femoral- and tibial-based deformity was more common than an isolated femoral-based deformity. As a clinical consequence, varus osteotomies to treat lateral compartment osteoarthritis must be performed at the tibial site or as a double-level osteotomy in a relevant number of patients to avoid an oblique joint line.

[Surgical approaches to tibial plateau fractures].

PubMed

Krause, Matthias; Müller, Gunnar; Frosch, Karl-Heinz

2018-06-06

Intra-articular tibial plateau fractures can present a surgical challenge due to complex injury patterns and compromised soft tissue. The treatment goal is to spare the soft tissue and an anatomical reconstruction of the tibial articular surface. Depending on the course of the fracture, a fracture-specific access strategy is recommended to provide correct positioning of the plate osteosynthesis. While the anterolateral approach is used in the majority of lateral tibial plateau fractures, only one third of the joint surface is visible; however, posterolateral fragments require an individual approach, e. g. posterolateral or posteromedial. If necessary, osteotomy of the femoral epicondyles can improve joint access for reduction control. Injuries to the posterior columns should be anatomically reconstructed and biomechanically correctly addressed via posterior approaches. Bony posterior cruciate ligament tears can be refixed via a minimally invasive posteromedial approach.

Novel implant for peri-prosthetic proximal tibia fractures.

PubMed

Tran, Ton; Chen, Bernard K; Wu, Xinhua; Pun, Chung Lun

2018-03-01

Repair of peri-prosthetic proximal tibia fractures is very challenging in patients with a total knee replacement or arthroplasty. The tibial component of the knee implant severely restricts the fixation points of the tibial implant to repair peri-prosthetic fractures. A novel implant has been designed with an extended flange over the anterior of tibial condyle to provide additional points of fixation, overcoming limitations of existing generic locking plates used for proximal tibia fractures. Furthermore, the screws fixed through the extended flange provide additional support to prevent the problem of subsidence of tibial component of knee implant. The design methodology involved extraction of bone data from CT scans into a flexible CAD format, implant design and structural evaluation and optimisation using FEM as well as prototype development and manufacture by selective laser melting 3D printing technology with Ti6Al4 V powder. A prototype tibia implant was developed based on a patient-specific bone structure, which was regenerated from the CT images of patient's tibia. The design is described in detail and being applied to fit up to 80% of patients, for both left and right sides based on the average dimensions and shape of the bone structure from a wide range of CT images. A novel tibial implant has been developed to repair peri-prosthetic proximal tibia fractures which overcomes significant constraints from the tibial component of existing knee implant. Copyright © 2018 Elsevier Ltd. All rights reserved.

Ceramic hemi-unicondylar arthroplasty in an adolescent patient with idiopathic tibial chondrolysis.

PubMed

Dombroski, Derek; Garino, Jonathan; Lee, Gwo-Chin

2009-06-01

Despite recent advances in cartilage regeneration and restoration procedures, isolated, large, full-thickness cartilage lesions in young patients continue to pose significant challenges to patients and orthopedic surgeons. Treatment options for this difficult problem have traditionally included arthrodesis, osteotomy, osteochondral allograft, and prosthetic reconstruction. We present a case of an adolescent patient with isolated idiopathic lateral tibial chondrolysis treated with a custom ceramic hemi-unicondylar hemiarthroplasty. Preoperatively, a 3-dimensional computed tomography scan of the patient's knee was obtained to begin manufacturing a conforming custom ceramic insert that would articulate between the tibial base plate and the patient's native lateral femoral cartilage. Through a lateral parapatellar approach, the tibial preparation was carried out using the Zimmer M/G unicompartmental knee system (Warsaw, Indiana), and the tibial base plate was cemented into position in the standard fashion. A custom, conforming, prefabricated ceramic insert (CeramTec, Memphis, Tennessee) was then inserted onto the tibial base plate. At 5-year follow-up, this salvage procedure was successful in relieving pain and restoring function in this young patient. There were no signs of implant loosening or lysis. Magnetic resonance imaging of the knee at last follow-up revealed that the cartilage thickness of the patient's lateral femoral condyle remained unchanged. Unicondylar hemiarthroplasty performed in patients with large unipolar lesions in the knee can provide durable and reliable pain relief. Ceramic is a viable material that can be considered for articulation with native cartilage.

Bilateral periprosthetic tibial stress fracture after total knee arthroplasty: A case report.

PubMed

Ozdemir, Guzelali; Azboy, Ibrahim; Yilmaz, Baris

2016-01-01

Periprosthetic fractures around the knee after total knee arthroplasty can be seen in the femur, tibia and patella. The tibial fractures are rare cases. Our case with bilateral tibial stress fracture developed after total knee arthroplasty (TKA) is the first of its kind in the literature. 75-year-old male patient with bilateral knee osteoarthritis had not benefited from conservative treatment methods previously applied. Left TKA was applied. In the second month postoperatively, periprosthetic tibial fracture was identified and osteosynthesis was implemented with locked tibia proximal plate-screw. Bone union in 12 weeks was observed in his follow-ups. After 15 months of his first operation, TKA was applied to the right knee. Postoperatively in the second month, as in the first operation, periprosthetic tibial fracture was detected. Osteosynthesis with locking plate-screw was applied and union in 12 weeks was observed in his follow-up. He was seen mobilized independently and without support in the last control of the case made in the 24th month after the second operation. The number of TKA applications is expected to increase in the future. The incidence of periprosthetic fractures should also be expected to increase in these cases. Periprosthetic tibial fractures after TKA are rarely seen. The treatment of periprosthetic fractures around the knee after TKA can be difficult. In the case of persistent pain in the upper end of the tibia after the surgery, stress fracture should be considered. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Tibial avulsion fracture of the posterior root of the medial meniscus in a skeletally-immature child - a case report.

PubMed

Matava, Matthew J; Kim, Young-Mo

2011-01-01

It has been theorized that a traumatic tibial avulsion fracture of the posterior root of the medial meniscus (MM) is the cause of the so-called meniscus ossicle (MO). We report the delayed appearance of a tibial avulsion fracture of the posterior root of the MM after a valgus, twisting injury in a 12-year-old boy with open physes. Magnetic resonance imaging (MRI) scans performed 3 days after the injury did not demonstrate a definitive tibial avulsion fracture of the posterior root of the MM; whereas, a repeat MRI for 3 months post-injury did. Medial extrusion of the MM was also noted on the 3 month MRI. Arthroscopic reattachment of the avulsed posterior root of the MM using a trans-physeal nonabsorbable suture tied over a proximal tibia staple was performed. Follow-up MRI at 6 months postoperatively demonstrated healing of the tibial avulsion fracture of the posterior root of the MM in an anatomic position. The patient had a complete resolution of symptoms and there was no angular deformity or limb-length discrepancy at 2 years postoperatively. To our knowledge, this is the first report describing a tibial avulsion fracture of the posterior root of the MM in a skeletally-immature patient successfully treated by a trans-physeal arthroscopic suture. This case also illustrates the development of the MO of the posterior root of the MM. Copyright © 2010 Elsevier B.V. All rights reserved.

Effect of tibial tuberosity advancement on femorotibial contact mechanics and stifle kinematics.

PubMed

Kim, Stanley E; Pozzi, Antonio; Banks, Scott A; Conrad, Bryan P; Lewis, Daniel D

2009-01-01

Objective- To evaluate the effects of tibial tuberosity advancement (TTA) on femorotibial contact mechanics and 3-dimensional kinematics in cranial cruciate ligament (CrCL)-deficient stifles of dogs. Study Design- In vitro biomechanical study. Animals- Unpaired pelvic limbs from 8 dogs, weighing 28-35 kg. Methods- Digital pressure sensors placed subjacent to the menisci were used to measure femorotibial contact force, contact area, peak and mean contact pressure, and peak pressure location with the limb under an axial load of 30% body weight and a stifle angle of 135 degrees . Three-dimensional static poses of the stifle were obtained using a Microscribe digitizing arm. Each specimen was tested under normal, CrCL-deficient, and TTA-treated conditions. Repeated measures analysis of variance with a Tukey post hoc test (P<.05) was used for statistical comparison. Results- Significant disturbances to all measured contact mechanic parameters were evident after CrCL transection, which corresponded to marked cranial tibial subluxation and internal tibial rotation in the CrCL-deficient stifle. No significant differences in any contact mechanic and kinematic parameters were detected between normal and TTA-treated stifles. Conclusion- TTA eliminates craniocaudal stifle instability during simulated weight-bearing and concurrently restores femorotibial contact mechanics to normal. Clinical Relevance- TTA may mitigate the progression of stifle osteoarthritis in dogs afflicted with CrCL insufficiency by eliminating cranial tibial thrust while preserving the normal orientation of the proximal tibial articulating surface.

Comparison of tibial shaft ski fractures in children and adults.

PubMed

Hamada, Tomo; Matsumoto, Kazu; Ishimaru, Daichi; Sumi, Hiroshi; Shimizu, Katsuji

2014-09-01

To examine whether child and adult skiers have different risk factors or mechanisms of injury for tibial shaft fractures. Descriptive epidemiological study. Prospectively analyzed the epidemiologic factors, injury types, and injury mechanisms at Sumi Memorial Hospital. This study analyzed information obtained from 276 patients with tibial fractures sustained during skiing between 2004 and 2012. We focused on 174 ski-related tibial shaft fractures with respect to the following factors: age, gender, laterality of fracture, skill level, mechanism of fracture (fall vs collision), scene of injury (steepness of slope), snow condition, and weather. Fracture pattern was graded according to Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification and mechanical direction [external (ER) or internal rotation (IR)]. Tibial shaft fractures were the most common in both children (89.3%) and adults (47.4%). There were no significant differences in gender, side of fracture, mechanism of fracture, snow condition, or weather between children and adults. Skill levels were significantly lower in children than in adults (P < 0.0001). Type A fractures were more dominant in children (73 cases, 72.3%) than in adults (39 cases, 53.4%). There was significantly more ER in children than in adults (P < 0.0001). Among children, female patients had significantly more IR than ER; in contrast, among adults, women were injured by ER. We found significant differences in some of these parameters, suggesting that child and adult skiers have different risk factors or mechanisms of injury for tibial shaft fractures.

Intercondylar roof impingement pressure after anterior cruciate ligament reconstruction in a porcine model.

PubMed

Iriuchishima, Takanori; Tajima, Goro; Ingham, Sheila J M; Shen, Wei; Horaguchi, Takashi; Saito, Akiyoshi; Smolinski, Patrick; Fu, Freddie H

2009-06-01

Anterior cruciate ligament (ACL) graft impingement against the intercondylar roof has been postulated, but not thoroughly investigated. The roof impingement pressure changes with different tibial and femoral tunnel positions in ACL reconstruction. Anterior tibial translation is also affected by the tunnel positions of ACL reconstruction. The study design included a controlled laboratory study. In 15 pig knees, the impingement pressure between ACL and intercondylar roof was measured using pressure sensitive film before and after ACL single bundle reconstruction. ACL reconstructions were performed in each knee with two different tibial and femoral tunnel position combinations: (1) tibial antero-medial (AM) tunnel to femoral AM tunnel (AM to AM) and (2) tibial postero-lateral (PL) tunnel to femoral High-AM tunnel (PL to High-AM). Anterior tibial translation (ATT) was evaluated after each ACL reconstruction using robotic/universal force-moment sensor testing system. Neither the AM to AM nor the PL to High-AM ACL reconstruction groups showed significant difference when compared with intact ACL in roof impingement pressure. The AM to AM group had a significantly higher failure load than PL to High-AM group. This study showed how different tunnel placements affect the ACL-roof impingement pressure and anterior-posterior laxity in ACL reconstruction. Anatomical ACL reconstruction does not cause roof impingement and it has a biomechanical advantage in ATT when compared with non-anatomical ACL reconstructions in the pig knee. There is no intercondylar roof impingement after anatomical single bundle ACL reconstruction.

Large animal models in experimental knee sports surgery: focus on clinical translation.

PubMed

Madry, Henning; Ochi, Mitsuo; Cucchiarini, Magali; Pape, Dietrich; Seil, Romain

2015-12-01

Large animal models play a crucial role in sports surgery of the knee, as they are critical for the exploration of new experimental strategies and the clinical translation of novel techniques. The purpose of this contribution is to provide critical aspects of relevant animal models in this field, with a focus on paediatric anterior cruciate ligament (ACL) reconstruction, high tibial osteotomy, and articular cartilage repair. Although there is no single large animal model strictly replicating the human knee joint, the sheep stifle joint shares strong similarities. Studies in large animal models of paediatric ACL reconstruction identified specific risk factors associated with the different surgical techniques. The sheep model of high tibial osteotomy is a powerful new tool to advance the understanding of the effect of axial alignment on the lower extremity on specific issues of the knee joint. Large animal models of both focal chondral and osteochondral defects and of osteoarthritis have brought new findings about the mechanisms of cartilage repair and treatment options. The clinical application of a magnetic device for targeted cell delivery serves as a suitable example of how data from such animal models are directly translated into in clinical cartilage repair. As novel insights from studies in these translational models will advance the basic science, close cooperation in this important field of clinical translation will improve current reconstructive surgical options and open novel avenues for regenerative therapies of musculoskeletal disorders.

Magnetic Resonance Imaging Assessment of Intra-Articular Structures in the Canine Stifle Joint after Implantation of a Titanium Tibial Plateau Levelling Osteotomy Plate.

PubMed

Feichtenschlager, Christian; Gerwing, Martin; Failing, Klaus; Peppler, Christine; Kása, Andreas; Kramer, Martin; von Pückler, Kerstin H

2018-06-02

 To determine the effectiveness of magnetic resonance imaging (MRI) in the evaluation of anatomical stifle structures with respect to implant positioning after tibial plateau levelling osteotomy (TPLO) using a titanium plate.  Selected sagittal and dorsal sequences of pre- and postoperative MRI (1.0 T scanner) of 13 paired ( n  = 26) sound cadaveric stifle joints were evaluated. The effect of susceptibility artifact on adjacent anatomical stifle structures was graded from 0 to 5. The impact of implant positioning regarding assessment score was calculated using Spearman's rank correlation coefficient.  Sagittal turbo spin echo (TSE)-acquired images enabled interpretation of most soft tissue, osseous and cartilage structures without detrimental effect of susceptibility artifact distortions. In T2-weighted TSE images, the cranial cruciate ligament and caudal horn of the medial meniscus could be evaluated, independent of implant position, without any susceptibility artifact in all specimens. T2-weighted fast field echo, water selective, balanced fast field echo and short tau inversion recovery were most markedly affected by susceptibility artifact.  In selected TSE sequences, MRI allows evaluation of critical intra-articular structures after titanium TPLO plate implantation. Further investigations with confirmed stifle pathologies in dogs are required, to evaluate the accuracy of MRI after TPLO in clinical cases in this context. Schattauer GmbH Stuttgart.

Tibial and fibular nerves evaluation using intraoperative electromyography in rats.

PubMed

Nepomuceno, André Coelho; Politani, Elisa Landucci; Silva, Eduardo Guandelini da; Salomone, Raquel; Longo, Marco Vinicius Losso; Salles, Alessandra Grassi; Faria, José Carlos Marques de; Gemperli, Rolf

2016-08-01

To evaluate a new model of intraoperative electromyographic (EMG) assessment of the tibial and fibular nerves, and its respectives motor units in rats. Eight Wistar rats underwent intraoperative EMG on both hind limbs at two different moments: week 0 and week 12. Supramaximal electrical stimulation applied on sciatic nerve, and compound muscle action potential recorded on the gastrocnemius muscle (GM) and the extensor digitorum longus muscle (EDLM) through electrodes at specifics points. Motor function assessment was performaced through Walking Track Test. Exposing the muscles and nerves for examination did not alter tibial (p=0.918) or fibular (p=0.877) function between the evaluation moments. Electromyography of the GM, innervated by the tibial nerve, revealed similar amplitude (p=0.069) and latency (p=0.256) at week 0 and at 12 weeks, creating a standard of normality. Meanwhile, electromyography of the EDLM, innervated by the fibular nerve, showed significant differences between the amplitudes (p=0.003) and latencies (p=0.021) at the two different moments of observation. Intraoperative electromyography determined and quantified gastrocnemius muscle motor unit integrity, innervated by tibial nerve. Although this study was not useful to, objectively, assess extensor digitorum longus muscle motor unit, innervated by fibular nerve.

Quantitative comparison of the microscopic anatomy of the human ACL femoral and tibial entheses.

PubMed

Beaulieu, Mélanie L; Carey, Grace E; Schlecht, Stephen H; Wojtys, Edward M; Ashton-Miller, James A

2015-12-01

The femoral enthesis of the human anterior cruciate ligament (ACL) is known to be more susceptible to injury than the tibial enthesis. To determine whether anatomic differences might help explain this difference, we quantified the microscopic appearance of both entheses in 15 unembalmed knee specimens using light microscopy, toluidine blue stain and image analysis. The amount of calcified fibrocartilage and uncalcified fibrocartilage, and the ligament entheseal attachment angle were then compared between the femoral and tibial entheses via linear mixed-effects models. The results showed marked differences in anatomy between the two entheses. The femoral enthesis exhibited a 3.9-fold more acute ligament attachment angle than the tibial enthesis (p<0.001), a 43% greater calcified fibrocartilage tissue area (p<0.001), and a 226% greater uncalcified fibrocartilage depth (p<0.001), with the latter differences being particularly pronounced in the central region. We conclude that the ACL femoral enthesis has more fibrocartilage and a more acute ligament attachment angle than the tibial enthesis, which provides insight into why it is more vulnerable to failure. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Automated Measurement of Patient-Specific Tibial Slopes from MRI

PubMed Central

Amerinatanzi, Amirhesam; Summers, Rodney K.; Ahmadi, Kaveh; Goel, Vijay K.; Hewett, Timothy E.; Nyman, Edward

2017-01-01

Background: Multi-planar proximal tibial slopes may be associated with increased likelihood of osteoarthritis and anterior cruciate ligament injury, due in part to their role in checking the anterior-posterior stability of the knee. Established methods suffer repeatability limitations and lack computational efficiency for intuitive clinical adoption. The aims of this study were to develop a novel automated approach and to compare the repeatability and computational efficiency of the approach against previously established methods. Methods: Tibial slope geometries were obtained via MRI and measured using an automated Matlab-based approach. Data were compared for repeatability and evaluated for computational efficiency. Results: Mean lateral tibial slope (LTS) for females (7.2°) was greater than for males (1.66°). Mean LTS in the lateral concavity zone was greater for females (7.8° for females, 4.2° for males). Mean medial tibial slope (MTS) for females was greater (9.3° vs. 4.6°). Along the medial concavity zone, female subjects demonstrated greater MTS. Conclusion: The automated method was more repeatable and computationally efficient than previously identified methods and may aid in the clinical assessment of knee injury risk, inform surgical planning, and implant design efforts. PMID:28952547

Severe lateral tibial bowing with short stature in two siblings--a provisionally novel syndrome.

PubMed

Zitano, Lia; Loder, Randall T; Cohen, Mervyn D; Weaver, David D

2012-09-01

In this report, we describe two siblings with short stature and severe lateral tibial bowing. In the younger sibling, the bowing was bilateral, while in the older sib, it was unilateral. However, both showed bilateral abnormalities of the distal tibial epiphyses and growth plates. Pseudoarthrosis of the left distal tibial metaphysis and subsequent spontaneous resolution of the abnormality occurred in the younger sibling. The fibulas of both children were of normal diameter and were straight, except for the distal ends. Surgery has almost completely corrected the lower leg bowing in both patients. The type of tibial bowing seen in these children can be associated with a number of syndromes, such as neurofibromatosis type I, Weismann-Netter syndrome, and a variety of environmental caused disorders, such as vitamin D deficient rickets. However, the severity of the bowing present in our patients and the absence of other clinical features differentiates this condition from those reported in the literature. We posit that the condition in the children presented here represents an as yet undescribed syndrome, which is likely to be of genetic origin. Copyright © 2012 Wiley Periodicals, Inc.

High field gradient particle accelerator

DOEpatents

Nation, John A.; Greenwald, Shlomo

1989-01-01

A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle.

Pseudoaneurysm as a complication of ankle arthroscopy.

PubMed

Mariani, P P; Mancini, L; Giorgini, T L

2001-04-01

We describe a case of pseudoaneurysm of the anterior tibial artery as a complication after arthroscopic ankle synovectomy, in which standard anterolateral and anteromedial portals were used. Pseudoaneurysm has been previously reported as a complication in ankle arthroscopy with the use of the anterocentral portal. Previously described anatomic variations of the tibial artery and its close relationship with the anterior ankle capsule may complicate arthroscopic surgery, especially when aggressive synovectomy is performed. Anterior tibial artery aneurysm is a rare complication of ankle arthroscopy, but its potential catastrophic sequelae must not be underestimated.

Electron heating and acceleration during magnetic reconnection

NASA Astrophysics Data System (ADS)

Dahlin, Joel

2017-10-01

Magnetic reconnection is thought to be an important driver of energetic particles in a variety of astrophysical phenomena such as solar flares and magnetospheric storms. However, the observed fraction of energy imparted to a nonthermal component can vary widely in different regimes. We use kinetic particle-in-cell (PIC) simulations to demonstrate the important role of the non-reversing (guide) field in controlling the efficiency of electron acceleration in collisionless reconnection. In reconnection where the guide field is smaller than the reconnecting component, the dominant electron accelerator is a Fermi-type mechanism that preferentially energizes the most energetic particles. In strong guide field reconnection, the field-line contraction that drives the Fermi mechanism becomes weak. Instead, parallel electric fields are primarily responsible for driving electron heating but are ineffective in driving the energetic component of the spectrum. Three-dimensional simulations reveal that the stochastic magnetic field that develops during 3D guide field reconnection plays a vital role in particle acceleration and transport. The reconnection outflows that drive Fermi acceleration also expel accelerating particles from energization regions. In 2D reconnection, electrons are trapped in island cores and acceleration ceases, whereas in 3D the stochastic magnetic field enables energetic electrons to leak out of islands and freely sample regions of energy release. A finite guide field is required to break initial 2D symmetry and facilitate escape from island structures. We show that reconnection with a guide field comparable to the reconnecting field generates the greatest number of energetic electrons, a regime where both (a) the Fermi mechanism is an efficient driver and (b) energetic electrons may freely access acceleration sites. These results have important implications for electron acceleration in solar flares and reconnection-driven dissipation in turbulence.

SPECT/CT tracer uptake is influenced by tunnel orientation and position of the femoral and tibial ACL graft insertion site.

PubMed

Hirschmann, Michael T; Mathis, Dominic; Rasch, Helmut; Amsler, Felix; Friederich, Niklaus F; Arnold, Markus P

2013-02-01

SPECT/CT is a hybrid imaging modality, which combines a 3D scintigraphy (SPECT) and a conventional computerised tomography (CT). SPECT/CT allows accurate anatomical localisation of metabolic tracer activity. It allows the correlation of surgical factors such as tunnel position and orientation with mechanical alignment, clinical outcome and biological factors. The purpose of this study was to investigate whether the SPECT/CT tracer uptake (intensity and distribution) correlates with the stability and laxity of the knee joint and the position and orientation of the tibial and femoral tunnels in patients after anterior cruciate ligament (ACL) reconstruction. A consecutive series of knees (n=66), with symptoms of pain and/or instability after ACL reconstruction were prospectively evaluated using clinical examination and 99mTc-HDP-SPECT/CT. Clinical laxity testing was performed using the Rolimeter (Ormed, Freiburg, Germany) including Lachman testing (0-2 mm, 3-5 mm, 6-10 mm, >10 mm), anterior drawer test (0-2 mm, 3-5 mm, 6-10 mm, >10 mm), pivot shift test (positive versus negative) and patient-based subjective instability (yes versus no). For analysis of SPECT/CT tracer uptake a previously validated SPECT/CT localisation scheme consisting of 17 tibial, nine femoral and four patellar regions on standardised axial, coronal, and sagittal slices was used. The tracer activity on SPECT/CT was localised and recorded using a 3D volumetric and quantitative analysis software. Mean, standard deviation, minimum and maximum of grading for each area of the localisation scheme were recorded. The position and orientation of the tibial and femoral tunnel was assessed using a previously published method on 3D-CT. Correlation of instability, pivot shift as well as clinical laxity testing with 99mTc-HDP-SPECT/CT tracer uptake intensity and distribution showed no significant correlation. 99mTc-HDP-SPECT/CT tracer uptake correlated significantly with the position and orientation of the ACL graft. A more horizontal femoral graft position showed significantly increased tracer uptake within the superior and posterior femoral regions. A more posteriorly-placed femoral insertion site showed significantly more tracer uptake within the femoral and tibial tunnel regions. A more vertical or a less medial tibial tunnel orientation showed significant increased uptake within the tibial and femoral tunnel regions. A more anterior tibial tunnel position showed significantly more tracer uptake in the femoral and tibial tunnel regions as well as the entire tibiofemoral joint. SPECT/CT tracer uptake intensity and distribution showed a significant correlation with the femoral and tibial tunnel position and orientation in patients with symptomatic knees after ACL reconstruction. No correlation was found with stability or clinical laxity. SPECT/CT tracer uptake distribution has the potential to give us important information on joint homeostasis and remodelling after ACL reconstruction. It might help to predict ACL graft failure and improve our surgical ACL reconstruction technique in finding the optimal tunnel and graft position and orientation.

Does a conservative tibial cut in conventional total knee arthroplasty violate the deep medial collateral ligament?

PubMed

Maes, Michael; Luyckx, Thomas; Bellemans, Johan

2014-11-01

Based on the anatomy of the deep medial collateral ligament (MCL), it was hypothesized that at least part of its cross-sectional insertion area is jeopardized while performing a standard tibial cut in conventional total knee arthroplasty (TKA). The aim of this study was to determine whether it is anatomically possible to preserve the tibial deep MCL insertion during conventional TKA. Thirty-three unpaired cadaveric knee specimens were used for this study. Knees with severe varus/valgus deformity or damage to the medial structures of the knee were excluded. In the first part of the study, the dimensions of the tibial insertion of the deep MCL and its relationship to the joint line were recorded. Next, the cross-sectional area of the deep MCL insertion was determined using calibrated digital photographic analysis. In the second part, the effect of a standard 9-mm 3° sloped tibial cut on the structural integrity of the deep MCL cross-sectional insertion area was determined using conventional instrumentation. The proximal border of the deep MCL insertion site on the tibia was located on average 4.7 ± 1.2 mm distally to the joint line. After performing a standard 9-mm 3° sloped tibial cut, on average 54% of the deep MCL insertion area was resected. In 29% of the cases, the deep MCL insertion area was completely excised. The deep MCL cannot routinely be preserved in conventional TKA. The deep MCL insertion is at risk and may be jeopardized in case of a tibial cut 9 mm below the native joint line. As the deep MCL is a distinct medial stabilizer and plays an important role in rotational stability, this may have implications in future designs of both unicondylar and total knee arthroplasty, but further research is necessary.

Comparison of Clinical Results and Injury Risk of Posterior Tibial Cortex Between Attune and Press Fit Condylar Sigma Knee Systems.

PubMed

Song, Sang Jun; Park, Cheol Hee; Liang, Hu; Kang, Se Gu; Park, Jong Jun; Bae, Dae Kyung

2018-02-01

We compared clinical and radiographic results after total knee arthroplasty (TKA) using Attune and Press Fit Condylar Sigma, and investigated whether use of the current prosthesis increased injury risk to the tibial cortex in Asian patients. We also assessed whether a preoperative posterior tibial slope angle (PSA) is associated with the injury when using the current prosthesis. The 300 TKAs with Attune (group A) were compared to the 300 TKAs with Press Fit Condylar Sigma (group B). Demographics were not different, except follow-up periods (24.8 vs 33.3 months, P < .001). The Western Ontario and McMaster Universities Index and range of motion were compared. A minimum distance between tibial component stem and posterior tibial cortex (mDSC) was compared. The correlation between preoperative PSA and mDSC was analyzed in group A. The postoperative Western Ontario and McMaster Universities Index and range of motion of group A were better than those of group B (17.7 vs 18.8, P = .004; 131.4° vs 129.0°, P = .008). The mDSC was shorter in group A (6.3 vs 7.0 mm, P < .001), which made up a higher proportion of the high-risk group for posterior tibial cortical injury with an mDSC of <4 mm (20.0% vs 10.7%, P = .002). A negative correlation was found between the preoperative PSA and mDSC in group A (r = -0.205, P < .001). The TKA using the current prosthesis provided more satisfactory results than the TKA using the previous prosthesis. However, the injury risk to the posterior tibial cortex increased in the knees with a large PSA when using the current prosthesis for Asian patients. Copyright © 2017 Elsevier Inc. All rights reserved.

Tibial coverage, meniscus position, size and damage in knees discordant for joint space narrowing – data from the Osteoarthritis Initiative

PubMed Central

Bloecker, K.; Guermazi, A.; Wirth, W.; Benichou, O.; Kwoh, C.K.; Hunter, D.J.; Englund, M.; Resch, H.; Eckstein, F.

2013-01-01

SUMMARY Introduction Meniscal extrusion is thought to be associated with less meniscus coverage of the tibial surface, but the association of radiographic disease stage with quantitative measures of tibial plateau coverage is unknown. We therefore compared quantitative and semi-quantitative measures of meniscus position and morphology in individuals with bilateral painful knees discordant on medial joint space narrowing (mJSN). Methods A sample of 60 participants from the first half (2,678 cases) of the Osteoarthritis Initiative cohort fulfilled the inclusion criteria: bilateral frequent pain, Osteoarthritis Research Society International (OARSI) mJSN grades 1–3 in one, no-JSN in the contra-lateral (CL), and no lateral JSN in either knee (43 unilateral mJSN1; 17 mJSN2/3; 22 men, 38 women, body mass index (BMI) 31.3 ± 3.9 kg/m2). Segmentation and three-dimensional quantitative analysis of the tibial plateau and meniscus, and semi-quantitative evaluation of meniscus damage (magnetic resonance imaging (MRI) osteoarthritis knee score – MOAKS) was performed using coronal 3T MR images (MPR DESSwe and intermediate-weighted turbo spin echo (IW-TSE) images). CL knees were compared using paired t-tests (between-knee, within-person design). Results Medial tibial plateau coverage was 36 ± 9% in mJSN1 vs 45 ± 8% in CL no-JSN knees, and was 31 ± 9% in mJSN2/3 vs 46 ± 6% in no-JSN knees (both P < 0.001). mJSN knees showed greater meniscus extrusion and damage (MOAKS), but no significant difference in meniscus volume. No significant differences in lateral tibial coverage, lateral meniscus morphology or position were observed. Conclusions Knees with medial JSN showed substantially less medial tibial plateau coverage by the meniscus. We suggest that the less meniscal coverage, i.e., less mechanical protection may be a reason for greater rates of cartilage loss observed in JSN knees. PMID:23220556

All-polyethylene tibial components in distal femur limb-salvage surgery: a finite element analysis based on promising clinical outcomes.

PubMed

Tang, Fan; Zhou, Yong; Zhang, Wenli; Min, Li; Shi, Rui; Luo, Yi; Duan, Hong; Tu, Chongqi

2017-04-04

Whether all-polyethylene tibial (APT) components are beneficial to patients who received distal femur limb-salvage surgery lacks high-quality clinical follow-up and mechanical evidence. This study aimed to investigate the biomechanics of the distal femur reconstructed with APT tumor knee prostheses using finite element (FE) analysis based on our previous, promising clinical outcome. Three-dimensional FE models that use APT and metal-backed tibial (MBT) prostheses to reconstruct distal femoral bone defects were developed and input into the Abaqus FEA software version 6.10.1. Mesh refinement tests and gait simulation with a single foot both in the upright and 15°-flexion positions with mechanical loading were conducted. Stress distribution analysis was compared between APT and MBT at the two static positions. For both prosthesis types, the stress was concentrated on the junction of the stem and shaft, and the maximum stress in the femoral axis base was more than 100 Mpa. The stress on the tibial surface was relatively distributed, which was 1-19 MPa. The stress on the tibial bone-cement layer of the APT prosthesis was approximately 20 times higher than that on the MBT prosthesis in the same region. The stress on the proximal tibial cancellous bone and cortical bone of the APT prosthesis was 3-5 times greater than that of the MBT prosthesis, and it was more distributed. Although the stress of bone-cement around the APT component is relatively high, the stress was better distributed at the polyethylene-cement-bone interface in APT than in MBT prosthesis, which effectively protects the proximal tibia in distal femur tumor knee prosthesis replacement. These results should be considered when selecting the appropriate tibial component for a patient, especially under the foreseeable conditions of osteoporosis.

THE MECHANISMS OF ELECTRON ACCELERATION DURING MULTIPLE X LINE MAGNETIC RECONNECTION WITH A GUIDE FIELD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Huanyu; Lu, Quanming; Huang, Can

2016-04-20

The interactions between magnetic islands are considered to play an important role in electron acceleration during magnetic reconnection. In this paper, two-dimensional particle-in-cell simulations are performed to study electron acceleration during multiple X line reconnection with a guide field. Because the electrons remain almost magnetized, we can analyze the contributions of the parallel electric field, Fermi, and betatron mechanisms to electron acceleration during the evolution of magnetic reconnection through comparison with a guide-center theory. The results show that with the magnetic reconnection proceeding, two magnetic islands are formed in the simulation domain. Next, the electrons are accelerated by both themore » parallel electric field in the vicinity of the X lines and the Fermi mechanism due to the contraction of the two magnetic islands. Then, the two magnetic islands begin to merge into one, and, in such a process, the electrons can be accelerated by both the parallel electric field and betatron mechanisms. During the betatron acceleration, the electrons are locally accelerated in the regions where the magnetic field is piled up by the high-speed flow from the X line. At last, when the coalescence of the two islands into one big island finishes, the electrons can be further accelerated by the Fermi mechanism because of the contraction of the big island. With the increase of the guide field, the contributions of the Fermi and betatron mechanisms to electron acceleration become less and less important. When the guide field is sufficiently large, the contributions of the Fermi and betatron mechanisms are almost negligible.« less

Absence of a Tourniquet Does Not Affect Fixation of Cemented TKA: A Randomized RSA Study of 70 Patients.

PubMed

Ejaz, Ashir; Laursen, Anders C; Jakobsen, Thomas; Rasmussen, Sten; Nielsen, Poul Torben; Laursen, Mogens B

2015-12-01

We aimed to determine whether not using a tourniquet in cemented TKA would affect migration of the tibial component measured by radiosterometric analysis (RSA). Seventy patients were randomized into a tourniquet group and a non-tourniquet group and using model-based RSA, the migration of the tibial component was analyzed. Primary and secondary outcome measures were maximum total point motion (MTPM) and translations and rotations. Follow-up period was 2 years. The tibial component was well fixated in both groups and no significant difference in migration between the two groups was detected (P=0.632). Mean MTPM (SD) was 0.47 mm (0.16) in the tourniquet group and 0.45 mm (0.21) in the non-tourniquet group. Absence of tourniquet indicates that stable fixation of the tibial component can be achieved in cemented TKA. Copyright © 2015 Elsevier Inc. All rights reserved.

Interlocking-based attachment during locomotion in the beetle Pachnoda marginata (Coleoptera, Scarabaeidae)

PubMed Central

Bußhardt, Philipp; Kunze, Daniel; Gorb, Stanislav N.

2014-01-01

The attachment function of tibial spurs and pretarsal claws in the beetle Pachnoda marginata (Coleoptera, Scarabaeidae) during locomotion was examined in this study. First, we measured the angle, at which the beetles detached from substrates with different roughness. At a surface roughness of 12 μm and higher, intact animals were able to cling to a completely tilted platform (180°). Second, we estimated the forces the beetles could exert in walking on smooth and rough cylinders of different diameters, on a plane and also between two plates. To elucidate the role of the individual structures, we ablated them consecutively. We found tibial spurs not to be in use in walking on flat substrates. On some of the curved substrates, ablation of tibial spurs caused an effect. A clear effect of tibial spurs was revealed in walking between two plates. Thus, these structures are probably used for generating propulsion in narrowed spaces. PMID:25385502

Etiologic factors in the development of medial tibial stress syndrome: a review of the literature.

PubMed

Tweed, Jo L; Avil, Steven J; Campbell, Jackie A; Barnes, Mike R

2008-01-01

Medial tibial stress syndrome is a type of exercise-induced leg pain that is common in recreational and competitive athletes. Although various studies have attempted to find the exact pathogenesis of this common condition, it remains unknown. Various theories in literature from 1976 to 2006 were reviewed using key words. Until recently, inflammation of the periosteum due to excessive traction was thought to be the most likely cause of medial tibial stress syndrome. This periostitis has been hypothesized by some authors to be caused by the tearing away of the muscle fibers at the muscle-bone interface, although there are several suggestions as to which, if any, muscle is responsible. Recent studies have supported the view that medial tibial stress syndrome is not an inflammatory process of the periosteum but instead a stress reaction of bone that has become painful.

Achilles lengthening/posterior tibial tenotomy with immediate weightbearing for patients with significant comorbidities.

PubMed

Redfern, John C; Thordarson, David B

2008-03-01

Fixed equinovarus deformities can be challenging to treat especially in medically debilitated patients. The purpose of this study was to evaluate Achilles lengthening with posterior tibial tenotomy and immediate weightbearing in this difficult group of patients. Thirteen extremities in 10 patients underwent Achilles lengthening and posterior tibial tenotomy for fixed equinovarus deformities with significant medical comorbidities. Pre- and postoperative ambulatory status and deformities were noted. Average age at the time of surgery was 65 with an average duration of deformity 6.3 years. The average equinus corrected from 26 degrees to 1.2 degrees and the average varus deformity improved from -8.5 degrees to 2.7 degrees. All patients except one who was wheelchair-bound had a significant improvement in ambulatory status. Achilles lengthening with posterior tibial tenotomy allowed for immediate postoperative weightbearing with improvement in deformity and ambulatory status in this complicated patient group.

The Los Alamos Laser Acceleration of Particles Workshop and beginning of the advanced accelerator concepts field

NASA Astrophysics Data System (ADS)

Joshi, C.

2012-12-01

The first Advanced Acceleration of Particles-AAC-Workshop (actually named Laser Acceleration of Particles Workshop) was held at Los Alamos in January 1982. The workshop lasted a week and divided all the acceleration techniques into four categories: near field, far field, media, and vacuum. Basic theorems of particle acceleration were postulated (later proven) and specific experiments based on the four categories were formulated. This landmark workshop led to the formation of the advanced accelerator R&D program in the HEP office of the DOE that supports advanced accelerator research to this day. Two major new user facilities at Argonne and Brookhaven and several more directed experimental efforts were built to explore the advanced particle acceleration schemes. It is not an exaggeration to say that the intellectual breadth and excitement provided by the many groups who entered this new field provided the needed vitality to then recently formed APS Division of Beams and the new online journal Physical Review Special Topics-Accelerators and Beams. On this 30th anniversary of the AAC Workshops, it is worthwhile to look back at the legacy of the first Workshop at Los Alamos and the fine groundwork it laid for the field of advanced accelerator concepts that continues to flourish to this day.

Shock Transmission and Fatigue in Human Running.

PubMed

Verbitsky, Oleg; Mizrahi, Joseph; Voloshin, Arkady; Treiger, July; Isakov, Eli

1998-08-01

The goal of this research was to analyze the effects of fatigue on the shock waves generated by foot strike. Twenty-two subjects were instrumented with an externally attached, lightweight accelerometer placed over the tibial tuberosity. The subjects ran on a treadmill for 30 min at a speed near their anaerobic threshold. Fatigue was established when the end-tidal CO 2 pressure decreased. The results indicated that approximately half of the subjects reached the fatigue state toward the end of the test. Whenever fatigue occurred, the peak acceleration was found to increase. It was thus concluded that there is a clear association between fatigue and increased heel strike-induced shock waves. These results have a significant implication for the etiology of running injuries, since shock wave attenuation has been previously reported to play an important role in preventing such injuries.

Decline in bone mineral density with stress fractures in a woman on depot medroxyprogesterone acetate. A case report.

PubMed

Harkins, G J; Davis, G D; Dettori, J; Hibbert, M L; Hoyt, R A

1999-03-01

Depot medroxyprogesterone acetate is a popular contraceptive among young, physically active women. However, its administration has been linked to a relative decrease in estrogen levels. Since bone resorption is accelerated during hypoestrogenic states, there has been growing concern about the potential development of osteoporosis and fractures with the use of this contraceptive method. A physically active, 33-year-old woman demonstrated a 12.4% drop in femoral neck bone mineral density (BMD), 6.4% drop in lumbar BMD and 0.8% drop in total BMD with the subsequent development of a tibial stress fracture while on depot medroxyprogesterone acetate. Bone mineralization rapidly improved, and the stress fracture resolved with discontinuation of the medication. The long-term effects of depot medroxyprogesterone acetate on bone mineralization in physically active women should be evaluated more thoroughly.

Role of the fibula in the stability of diaphyseal tibial fractures fixed by intramedullary nailing.

PubMed

Galbraith, John G; Daly, Charles J; Harty, James A; Dailey, Hannah L

2016-10-01

For tibial fractures, the decision to fix a concomitant fibular fracture is undertaken on a case-by-case basis. To aid in this clinical decision-making process, we investigated whether loss of integrity of the fibula significantly destabilises midshaft tibial fractures, whether fixation of the fibula restores stability to the tibia, and whether removal of the fibula and interosseous membrane for expediency in biomechanical testing significantly influences tibial interfragmentary mechanics. Tibia/fibula pairs were harvested from six cadaveric donors with the interosseous membrane intact. A tibial osteotomy fracture was fixed by reamed intramedullary (IM) nailing. Axial, torsion, bending, and shear tests were completed for four models of fibular involvement: intact fibula, osteotomy fracture, fibular plating, and resected fibula and interosseous membrane. Overall construct stiffness decreased slightly with fibular osteotomy compared to intact bone, but this change was not statistically significant. Under low loads, the influence of the fibula on construct stability was only statistically significant in torsion (large effect size). Fibular plating stiffened the construct slightly, but this change was not statistically significant compared to the fibular osteotomy case. Complete resection of the fibula and interosseous membrane significantly decreased construct torsional stiffness only (large effect size). These results suggest that fixation of the fibula may not contribute significantly to the stability of diaphyseal tibial fractures and should not be undertaken unless otherwise clinically indicated. For testing purposes, load-sharing through the interosseous membrane contributes significantly to overall construct mechanics, especially in torsion, and we recommend preservation of these structures when possible. Copyright © 2016 Elsevier Ltd. All rights reserved.

Utility of cement injection to stabilize split-depression tibial plateau fracture by minimally invasive methods: A finite element analysis.

PubMed

Belaid, D; Vendeuvre, T; Bouchoucha, A; Brémand, F; Brèque, C; Rigoard, P; Germaneau, A

2018-05-08

Treatment for fractures of the tibial plateau is in most cases carried out by stable fixation in order to allow early mobilization. Minimally invasive technologies such as tibioplasty or stabilization by locking plate, bone augmentation and cement filling (CF) have recently been used to treat this type of fracture. The aim of this paper was to determine the mechanical behavior of the tibial plateau by numerically modeling and by quantifying the mechanical effects on the tibia mechanical properties from injury healing. A personalized Finite Element (FE) model of the tibial plateau from a clinical case has been developed to analyze stress distribution in the tibial plateau stabilized by balloon osteoplasty and to determine the influence of the cement injected. Stress analysis was performed for different stages after surgery. Just after surgery, the maximum von Mises stresses obtained for the fractured tibia treated with and without CF were 134.9 MPa and 289.9 MPa respectively on the plate. Stress distribution showed an increase of values in the trabecular bone in the treated model with locking plate and CF and stress reduction in the cortical bone in the model treated with locking plate only. The computed results of stresses or displacements of the fractured models show that the cement filling of the tibial depression fracture may increase implant stability, and decrease the loss of depression reduction, while the presence of the cement in the healed model renders the load distribution uniform. Copyright © 2018 Elsevier Ltd. All rights reserved.

Improvement of the knee center of rotation during walking after opening wedge high tibial osteotomy.

PubMed

Kim, Kyungsoo; Feng, Jun; Nha, Kyung Wook; Park, Won Man; Kim, Yoon Hyuk

2015-06-01

Accurate measurement of the center of rotation of the knee joint is indispensable for prediction of joint kinematics and kinetics in musculoskeletal models. However, no study has yet identified the knee center of rotations during several daily activities before and after high tibial osteotomy surgery, which is one surgical option for treating knee osteoarthritis. In this study, an estimation method for determining the knee joint center of rotation was developed by applying the optimal common shape technique and symmetrical axis of rotation approach techniques to motion-capture data and validated for typical activities (walking, squatting, climbing up stairs, walking down stairs) of 10 normal subjects. The locations of knee joint center of rotations for injured and contralateral knees of eight subjects with osteoarthritis, both before and after high tibial osteotomy surgery, were then calculated during walking. It was shown that high tibial osteotomy surgery improved the knee joint center of rotation since the center of rotations for the injured knee after high tibial osteotomy surgery were significantly closer to those of the normal healthy population. The difference between the injured and contralateral knees was also generally reduced after surgery, demonstrating increased symmetry. These results indicate that symmetry in both knees can be recovered in many cases after high tibial osteotomy surgery. Moreover, the recovery of center of rotation in the injured knee was prior to that of symmetry. This study has the potential to provide fundamental information that can be applied to understand abnormal kinematics in patients, diagnose knee joint disease, and design a novel implants for knee joint surgeries. © IMechE 2015.

Forefoot-rearfoot coupling patterns and tibial internal rotation during stance phase of barefoot versus shod running.

PubMed

Eslami, Mansour; Begon, Mickaël; Farahpour, Nader; Allard, Paul

2007-01-01

Based on twisted plate and mitered hinge models of the foot and ankle, forefoot-rearfoot coupling motion patterns can contribute to the amount of tibial rotation. The present study determined the differences of forefoot-rearfoot coupling patterns as well as excessive excursion of tibial internal rotation in shod versus barefoot conditions during running. Sixteen male subjects ran 10 times at 170 steps per minute under the barefoot and shod conditions. Forefoot-rearfoot coupling motions were assessed by measuring mean relative phase angle during five intervals of stance phase for the main effect of five time intervals and two conditions (ANOVA, P<0.05). Tibial internal rotation excursion was compared between the shod and barefoot conditions over the first 50% of stance phase using paired t-test, (P<0.05). Forefoot adduction/abduction and rearfoot eversion/inversion coupling motion patterns were significantly different between the conditions and among the intervals (P<0.05; effect size=0.47). The mean absolute relative angle was significantly modified to 37 degrees in-phase relationship at the heel-strike of running with shoe wears. No significant differences were noted in the tibial internal rotation excursion between shod and barefoot conditions. Significant variations in the forefoot adduction/abduction and rearfoot eversion/inversion coupling patterns could have little effect on the amount of tibial internal rotation excursion. Yet it remains to be determined whether changes in the frontal plane forefoot-rearfoot coupling patterns influence the tibia kinematics for different shoe wears or foot orthotic interventions. The findings question the rational for the prophylactic use of forefoot posting in foot orthoses.

Strain measurements of the tibial insert of a knee prosthesis using a knee motion simulator.

PubMed

Sera, Toshihiro; Iwai, Yuya; Yamazaki, Takaharu; Tomita, Tetsuya; Yoshikawa, Hideki; Naito, Hisahi; Matsumoto, Takeshi; Tanaka, Masao

2017-12-01

The longevity of a knee prosthesis is influenced by the wear of the tibial insert due to its posture and movement. In this study, we assumed that the strain on the tibial insert is one of the main reasons for its wear and investigated the influence of the knee varus-valgus angles on the mechanical stress of the tibial insert. Knee prosthesis motion was simulated using a knee motion simulator based on a parallel-link six degrees-of-freedom actuator and the principal strain and pressure distribution of the tibial insert were measured. In particular, the early stance phase obtained from in vivo X-ray images was examined because the knee is applied to the largest load during extension/flexion movement. The knee varus-valgus angles were 0° (neutral alignment), 3°, and 5° malalignment. Under a neutral orientation, the pressure was higher at the middle and posterior condyles. The first and second principal strains were larger at the high and low pressure areas, respectively. Even for a 3° malalignment, the load was concentrated at one condyle and the positive first principal strain increased dramatically at the high pressure area. The negative second principal strain was large at the low pressure area on the other condyle. The maximum equivalent strain was 1.3-2.1 times larger at the high pressure area. For a 5° malalignment, the maximum equivalent strain increased slightly. These strain and pressure measurements can provide the mechanical stress of the tibial insert in detail for determining the longevity of an artificial knee joint.

Effects of directly autotransplanted tibial bone marrow aspirates on bone regeneration and osseointegration of dental implants.

PubMed

Payer, Michael; Lohberger, Birgit; Strunk, Dirk; Reich, Karoline M; Acham, Stephan; Jakse, Norbert

2014-04-01

Aim of the pilot trial was to evaluate applicability and effects of directly autotransplanted tibial bone marrow (BM) aspirates on the incorporation of porous bovine bone mineral in a sinus lift model and on the osseointegration of dental implants. Six edentulous patients with bilaterally severely resorbed maxillae requiring sinus augmentation and implant treatment were included. During surgery, tibial BM was harvested and added to bone substitute material (Bio-Oss(®) ) at the randomly selected test site. At control sites, augmentation was performed with Bio-Oss(®) alone. The cellular content of each BM aspirate was checked for multipotency and surface antigen expression as quality control. Histomorphometric analysis of biopsies from the augmented sites after 3 and 6 months (during implantation) was used to evaluate effects on bone regeneration. Osseointegration of implants was evaluated with Periotest(®) and radiographic means. Multipotent cellular content in tibial BM aspirates was comparable to that in punctures from the iliac crest. No significant difference in amount of new bone formation and the integration of bone substitute particles was detected histomorphometrically. Periotest(®) values and radiographs showed successful osseointegration of inserted implants at all sites. Directly autotransplanted tibial BM aspirates did not show beneficial regenerative effects in the small study population (N = 6) of the present pilot trial. However, the proximal tibia proved to be a potential donor site for small quantities of BM. Future trials should clarify whether concentration of tibial BM aspirates could effect higher regenerative potency. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Anatomic mapping for surgical reconstruction of the proximal tibiofibular ligaments.

PubMed

See, Aaron; Bear, Russell R; Owens, Brett D

2013-01-01

Injury to the proximal tibiofibular joint is uncommon. Previous studies regarding the anatomy of this region have predominantly focused on joint orientation. As radiographic technology has advanced, later studies have attempted to evaluate the capsular anatomy. However, no reports specifically map the ligaments to this joint. The objectives of the current study were to define specific ligamentous structures that provide stability to the proximal tibiofibular joint, describe easily identifiable and reproducible surgical landmarks to aid in surgical reconstruction, and add to the understanding of the posterolateral structures of the knee previously described by other authors. The proximal tibiofibular joint ligaments were identified in 10 fresh-frozen cadaveric specimens. Average ligament length, width, and thickness and area of the footprints of the tibial and fibular attachments were measured. Distances from the ligament footprints to known anatomic landmarks (eg, Gerdy's tubercle, tibial articular surface, and fibular styloid) were also measured. The anterior ligament tibial attachment was a mean of 15.6 mm lateral and posterior to Gerdy's tubercle and 17.3 mm anterior and inferior from the fibular styloid. Posterior ligament tibial insertion was a mean of 15.7 mm inferior to the tibial articular surface on the tibial side and 14.2 mm medial and slightly inferior from the fibular styloid. Definable ligaments provide stability to the proximal tibiofibular joint and can be reconstructed in an anatomic fashion using the landmarks and parameters described. This information allows for an anatomic reconstruction of the proximal tibiofibular joint, which should provide patients with better outcomes and fewer postoperative sequelae. Copyright 2013, SLACK Incorporated.

Do physical examination and CT-scan measures of femoral neck anteversion and tibial torsion relate to each other?

PubMed

Sangeux, Morgan; Mahy, Jessica; Graham, H Kerr

2014-01-01

Informed clinical decision making for femoral and/or tibial de-rotation osteotomies requires accurate measurement of patient function through gait analysis and anatomy through physical examination of bony torsions. Validity of gait analysis has been extensively studied; however, controversy remains regarding the accuracy of physical examination measurements of femoral and tibial torsion. Comparison between CT-scans and physical examination measurements of femoral neck anteversion (FNA) and external tibial torsion (ETT) were retrospectively obtained for 98 (FNA) and 64 (ETT) patients who attended a tertiary hospital for instrumented gait analysis between 2007 and 2010. The physical examination methods studied for femoral neck anteversion were the trochanteric prominence angle test (TPAT) and the maximum hip rotation arc midpoint (Arc midpoint) and for external tibial torsion the transmalleolar axis (TMA). Results showed that all physical examination measurements statistically differed to the CT-scans (bias(standard deviation): -2(14) for TPAT, -10(12) for Arc midpoint and -16(9) for TMA). Bland and Altman plots showed that method disagreements increased with increasing bony torsions in all cases but notably for TPAT. Regression analysis showed that only TMA and CT-scan measurement of external tibial torsion demonstrated good (R(2)=57%) correlation. Correlations for both TPAT (R(2)=14%) and Arc midpoint (R(2)=39%) with CT-scan measurements of FNA were limited. We conclude that physical examination should be considered as screening techniques rather than definitive measurement methods for FNA and ETT. Further research is required to develop more accurate measurement methods to accompany instrumented gait analysis. Copyright © 2013. Published by Elsevier B.V.

Relationship between the skeletal maturation of the distal attachment of the patellar tendon and physical features in preadolescent male football players.

PubMed

Nakase, Junsuke; Aiba, Tomohiro; Goshima, Kenichi; Takahashi, Ryohei; Toratani, Tatsuhiro; Kosaka, Masahiro; Ohashi, Yoshinori; Tsuchiya, Hiroyuki

2014-01-01

The aim of this study was to compare ultrasonography stages of the tibial tuberosity development and physical features. This study examined 200 knees in 100 male football players aged 10-15 years. Tibial tuberosity development on ultrasonography was divided into 3 stages: Sonolucent stage (stage S), Individual stage (stage I), and Connective stage (stage C). Age, height, quadriceps and hamstring muscle tightness, and muscle strength in knee extension and flexion were determined. These findings were compared with the respective stages of development. The tibial tuberosity was stage S in 27 knees, stage I in 69 knees, and stage C in 104 knees, with right and left sides at the same stage in 95 %. Average age and height significantly increased with advancing tibial tuberosity development. Quadriceps tightness increased with tibial tuberosity development. Hamstring tightness decreased with development. The strength of both knee extension and flexion increased with advancing development, with a greater change seen in knee extension, hamstring/quadriceps ratio: stage C, 0.74; stage A, 0.64; stage E, 0.53. Osgood-Schlatter pathogenesis reportedly involves increased quadriceps tightness with rapidly increasing femoral length during tibial tuberosity development. In this study, it was confirmed that quadriceps tightness increased, yet hamstring tightness decreased, suggesting that quadriceps tightness is not due to femoral length alone. Other factors, including muscle strength, may be involved. The study shows that thigh muscle tightness and thigh muscle performance change with the skeletal maturation of the distal attachment of the patellar tendon. These results add new information to the pathogenesis of Osgood-Schlatter disease.

Delay in weight bearing in surgically treated tibial shaft fractures is associated with impaired healing: a cohort analysis of 166 tibial fractures.

PubMed

Houben, I B; Raaben, M; Van Basten Batenburg, M; Blokhuis, T J

2018-04-09

The relation between timing of weight bearing after a fracture and the healing outcome is yet to be established, thereby limiting the implementation of a possibly beneficial effect for our patients. The current study was undertaken to determine the effect of timing of weight bearing after a surgically treated tibial shaft fracture. Surgically treated diaphyseal tibial fractures were retrospectively studied between 2007 and 2015. The timing of initial weight bearing (IWB) was analysed as a predictor for impaired healing in a multivariate regression. Totally, 166 diaphyseal tibial fractures were included, 86 cases with impaired healing and 80 with normal healing. The mean age was 38.7 years (range 16-89). The mean time until IWB was significantly shorter in the normal fracture healing group (2.6 vs 7.4 weeks, p < 0.001). Correlation analysis yielded four possible confounders: infection requiring surgical intervention, fracture type, fasciotomy and open fractures. Logistic regression identified IWB as an independent predictor for impaired healing with an odds ratio of 1.13 per week delay (95% CI 1.03-1.25). Delay in initial weight bearing is independently associated with impaired fracture healing in surgically treated tibial shaft fractures. Unlike other factors such as fracture type or soft tissue condition, early resumption of weight bearing can be influenced by the treating physician and this factor therefore has a direct clinical relevance. This study indicates that early resumption of weight bearing should be the treatment goal in fracture fixation. 3b.

Effect of tibial plateau leveling osteotomy on femorotibial contact mechanics and stifle kinematics.

PubMed

Kim, Stanley E; Pozzi, Antonio; Banks, Scott A; Conrad, Bryan P; Lewis, Daniel D

2009-01-01

To evaluate the effects of tibial plateau leveling osteotomy (TPLO) on femorotibial contact mechanics and 3-dimensional (3D) kinematics in cranial cruciate ligament (CrCL)-deficient stifles of dogs. In vitro biomechanical study. Unpaired pelvic limbs from 8 dogs, weighing 28-35 kg. Digital pressure sensors placed subjacent to the menisci were used to measure femorotibial contact force, contact area, peak and mean contact pressure, and peak pressure location with the limb under an axial load of 30% body weight and a stifle angle of 135 degrees. Three-dimensional static poses of the stifle were obtained using a Microscribe digitizing arm. Each specimen was tested under normal, CrCL-deficient, and TPLO-treated conditions. Repeated measures analysis of variance with a Tukey post hoc test (P<.05) was used for statistical comparison. Significant disturbances to all measured contact mechanical variables were evident after CrCL transection, which corresponded to marked cranial tibial subluxation and increased internal tibial rotation in the CrCL-deficient stifle. No significant differences in 3D femorotibial alignment were observed between normal and TPLO-treated stifles; however, femorotibial contact area remained significantly smaller and peak contact pressures in both medial and lateral stifle compartments were positioned more caudally on the tibial plateau, when compared with normal. Whereas TPLO eliminates craniocaudal stifle instability during simulated weight bearing, the procedure fails to concurrently restore femorotibial contact mechanics to normal. Progression of stifle osteoarthritis in dogs treated with TPLO may be partly the result of abnormal stifle contact mechanics induced by altering the orientation of the proximal tibial articulating surface.

Effect of cranial cruciate ligament deficiency, tibial plateau leveling osteotomy, and tibial tuberosity advancement on contact mechanics and alignment of the stifle in flexion.

PubMed

Kim, Stanley E; Pozzi, Antonio; Banks, Scott A; Conrad, Bryan P; Lewis, Daniel D

2010-04-01

To assess contact mechanics and 3-dimensional (3-D) joint alignment in cranial cruciate ligament (CCL)-deficient stifles before and after tibial plateau leveling osteotomy (TPLO) and tibial tuberosity advancement (TTA) with the stifle in 90 degrees of flexion. In vitro biomechanical study. Cadaveric pelvic limb pairs (n=8) from dogs weighing 28-35 kg. Contralateral limbs were assigned to receive TPLO or TTA. Digital pressure sensors were used to measure femorotibial contact area, peak and mean contact pressure, and peak pressure location with the limb under a load of 30% body weight and stifle flexion angle of 90 degrees . 3-D poses were obtained using a Microscribe digitizer. Specimens were tested under normal, CCL deficient, and treatment conditions. Significant disturbances in alignment were not observed after CCL transection, although medial contact area was 10% smaller than normal (P=.003). There were no significant differences in contact mechanics or alignment between normal and TTA conditions; TPLO induced 6 degrees varus angulation (P<.001), 26% decrease in lateral peak pressure (P=.027), and 18% increase in medial mean pressure (P=.008) when compared with normal. Cranial tibial subluxation is nominal in CCL-deficient stifles loaded in flexion. Stifle alignment and contact mechanics are not altered by TTA, whereas TPLO causes mild varus and a subsequent increase in medial compartment loading. Cranial tibial subluxation of CCL-deficient stifles may not occur during postures that load the stifle in flexion. The significance of minor changes in loading patterns after TPLO is unknown.

Does Maximal External Tibial Component Rotation Influence Tibiofemoral Load Distribution in the Primary Knee Arthroplasty Setting: A Comparison of Neutral vs Maximal Anatomical External Rotatory States.

PubMed

Manning, William A; Ghosh, Kanishka M; Blain, Alasdair P; Longstaff, Lee M; Rushton, Steven P; Deehan, David J

2017-06-01

Tibial component rotation at time of knee arthroplasty can influence conformity, load transmission across the polyethylene surface, and perhaps ultimately determined survivorship. Optimal tibial component rotation on the cut surface is reliant on standard per operative manual stressing. This subjective assessment aims to balance constraint and stability of the articulation through a full arc of movement. Using a cadaveric model, computer navigation and under defined, previously validated loaded conditions mimicking the in vivo setting, the influence of maximal tibial component external rotation compared with the neutral state was examined for changes in laxity and tibiofemoral continuous load using 3D displacement measurement and an orthosensor continuous load sensor implanted within the polyethylene spacer in a simulated single radius total knee arthroplasty. No significant difference was found throughout arc of motion (0-115 degrees of flexion) for maximal varus and/or valgus or rotatory laxity between the 2 states. The neutral state achieved equivalence for mediolateral load distribution at each point of flexion. We have found that external rotation of the tibial component increased medial compartment load in comparison with the neutral position. Compared with the neutral state, external rotation consistently effected a marginal, but not significant reduction in lateral load under similar loading conditions. The effects were most pronounced in midflexion. On the basis of these findings, we would advocate for the midtibial tubercle point to determine tibial component rotation and caution against component external rotation. Copyright © 2017 Elsevier Inc. All rights reserved.

High field gradient particle accelerator

DOEpatents

Nation, J.A.; Greenwald, S.

1989-05-30

A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications is disclosed. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle. 10 figs.

Field Emission in Superconducting Accelerators: Instrumented Measurements for Its Understanding and Mitigation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geng, Rongli; Freyberger, Arne P.; Legg, Robert A.

Several new accelerator projects are adopting superconducting accelerator technology. When accelerating cavities maintain high RF gradients, field emission, the emission of electrons from cavity walls, can occur and may impact operational cavity gradient, radiological environment via activated components, and reliability. In this talk, we will discuss instrumented measurements of field emission from the two 1.1 GeV superconducting continuous wave (CW) linacs in CEBAF. The goal is to improve the understanding of field emission sources originating from cryomodule production, installation and operation. Such basic knowledge is needed in guiding field emission control, mitigation, and reduction toward high gradient and reliable operationmore » of superconducting accelerators.« less

Electron acceleration by a focused laser pulse in a static magnetic field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang Shihua; Wu Fengmin; Zhao Xianghao

2007-12-15

The model given by K. P. Singh [Phys. Rev. E 69, 056410 (2004)] for vacuum laser acceleration in a static magnetic field is revisited by including the effects of diffraction and the longitudinal electric field of a focused laser beam. Compared with a similar model without a static magnetic field, a simulation shows that electrons can gain much more net energy in this model even using the fifth-order corrected equations for the field of a focused laser beam. The acceleration mechanism and the acceleration efficiency are also investigated.

Effect of polarization and focusing on laser pulse driven auto-resonant particle acceleration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sagar, Vikram; Sengupta, Sudip; Kaw, Predhiman

2014-04-15

The effect of laser polarization and focusing is theoretically studied on the final energy gain of a particle in the Auto-resonant acceleration scheme using a finite duration laser pulse with Gaussian shaped temporal envelope. The exact expressions for dynamical variables viz. position, momentum, and energy are obtained by analytically solving the relativistic equation of motion describing particle dynamics in the combined field of an elliptically polarized finite duration pulse and homogeneous static axial magnetic field. From the solutions, it is shown that for a given set of laser parameters viz. intensity and pulse length along with static magnetic field, themore » energy gain by a positively charged particle is maximum for a right circularly polarized laser pulse. Further, a new scheme is proposed for particle acceleration by subjecting it to the combined field of a focused finite duration laser pulse and static axial magnetic field. In this scheme, the particle is initially accelerated by the focused laser field, which drives the non-resonant particle to second stage of acceleration by cyclotron Auto-resonance. The new scheme is found to be efficient over two individual schemes, i.e., auto-resonant acceleration and direct acceleration by focused laser field, as significant particle acceleration can be achieved at one order lesser values of static axial magnetic field and laser intensity.« less

Strain Response of the Anterior Cruciate Ligament to Uniplanar and Multiplanar Loads During Simulated Landings: Implications for Injury Mechanism.

PubMed

Kiapour, Ata M; Demetropoulos, Constantine K; Kiapour, Ali; Quatman, Carmen E; Wordeman, Samuel C; Goel, Vijay K; Hewett, Timothy E

2016-08-01

Despite basic characterization of the loading factors that strain the anterior cruciate ligament (ACL), the interrelationship(s) and additive nature of these loads that occur during noncontact ACL injuries remain incompletely characterized. In the presence of an impulsive axial compression, simulating vertical ground-reaction force during landing (1) both knee abduction and internal tibial rotation moments would result in increased peak ACL strain, and (2) a combined multiplanar loading condition, including both knee abduction and internal tibial rotation moments, would increase the peak ACL strain to levels greater than those under uniplanar loading modes alone. Controlled laboratory study. A cadaveric model of landing was used to simulate dynamic landings during a jump in 17 cadaveric lower extremities (age, 45 ± 7 years; 9 female and 8 male). Peak ACL strain was measured in situ and characterized under impulsive axial compression and simulated muscle forces (baseline) followed by addition of anterior tibial shear, knee abduction, and internal tibial rotation loads in both uni- and multiplanar modes, simulating a broad range of landing conditions. The associations between knee rotational kinematics and peak ACL strain levels were further investigated to determine the potential noncontact injury mechanism. Externally applied loads, under both uni- and multiplanar conditions, resulted in consistent increases in peak ACL strain compared with the baseline during simulated landings (by up to 3.5-fold; P ≤ .032). Combined multiplanar loading resulted in the greatest increases in peak ACL strain (P < .001). Degrees of knee abduction rotation (R(2) = 0.45; β = 0.42) and internal tibial rotation (R(2) = 0.32; β = 0.23) were both significantly correlated with peak ACL strain (P < .001). However, changes in knee abduction rotation had a significantly greater effect size on peak ACL strain levels than did internal tibial rotation (by ~2-fold; P < .001). In the presence of impulsive axial compression, the combination of anterior tibial shear force, knee abduction, and internal tibial rotation moments significantly increases ACL strain, which could result in ACL failure. These findings support multiplanar knee valgus collapse as one the primary mechanisms of noncontact ACL injuries during landing. Intervention programs that address multiple planes of loading may decrease the risk of ACL injury and the devastating consequences of posttraumatic knee osteoarthritis. © 2016 The Author(s).

Moore I postero-medial articular tibial fracture in alpine skiers: Surgical management and return to sports activity.

PubMed

Morin, Vincent; Pailhé, Régis; Sharma, Akash; Rouchy, René-Christopher; Cognault, Jérémy; Rubens-Duval, Brice; Saragaglia, Dominique

2016-06-01

Over the past 10 years, like many authors, we observed an increasing number of Moore I tibial plateau fractures related to alpine skiing for which the surgeon may face difficult choices regarding surgical approach and fixation means. Some authors have recently been suggesting a posterior approach associated to open reduction and osteosynthesis by a buttress plate. But in our knowledge there is no specific study on sports activity recovery after Moore I tibial fractures. The aim of this work was to assess sports activities and clinical outcomes after surgically treated Moore I tibial plateau fractures in an athletic population of skiers. We conducted a prospective case series between 2012 and 2014. This included fifteen patients aged 39.6±7 years whom presented with a Moore I tibial plateau fracture during a skiing accident. 12 cases (80%) presented with an associated tibial spine fracture. Treatment consisted of a standard antero-medial approach, with a medial para patellar arthrotomy to allow direct visualisation of articular reduction and spinal fixation. Two or three 6.5mm long cancellous bone screws were placed antero-posteriorly so as to ensure perfect compression of the fracture site. Radiological and functional results were assessed by an independent observer (Lysholm-Tegner, UCLA, KOOS scores) at the longest follow-up. Mean follow-up was 18.2±6 months (12-28). An immediate postoperative anatomical reduction was achieved in all cases and remained stable in time. At last follow-up Lysholm mean score was 85±14 points (59-100), UCLA score was 7.3±1.6 (4-10) and Tegner score was 4.6±1.3 (3-6). Mean KOOS score was 77±15 (54-97). 87% of patients had resumed their skiing activity and 93% were satisfied or very satisfied from their post-operative surgical outcome. We observed no pseudarthrosis or secondary varus displacement. In our series 87% of patients had resumed back to their sporting activities. Surgical management of Moore I tibial plateau fractures by isolated antero-posterior screwing provides excellent clinical and radiological results. The anteromedial incision has a dual advantage of anatomical reduction, tibial spine fixation (in 80% of our cases) and posteromedial fragment reduction. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tibial component coverage based on bone mineral density of the cut tibial surface during unicompartmental knee arthroplasty: clinical relevance of the prevention of tibial component subsidence.

PubMed

Lee, Yong Seuk; Yun, Ji Young; Lee, Beom Koo

2014-01-01

An optimally implanted tibial component during unicompartmental knee arthroplasty would be flush with all edges of the cut tibial surface. However, this is often not possible, partly because the tibial component may not be an ideal shape or because the ideal component size may not be available. In such situations, surgeons need to decide between component overhang and underhang and as to which sites must be covered and which sites could be undercovered. The objectives of this study were to evaluate the bone mineral density of the cut surface of the proximal tibia around the cortical rim and to compare the bone mineral density according to the inclusion of the cortex and the site-specific matched evaluation. One hundred and fifty consecutive patients (100 men and 50 women) were enrolled in this study. A quantitative computed tomography was used to determine the bone density of the cut tibial surface. Medial and lateral compartments were divided into anterior, middle, and posterior regions, and these three regions were further subdivided into two regions according to containment of cortex. The site-specific matched comparison (medial vs. lateral) of bone mineral density was performed. In medial sides, the mid-region, including the cortex, showed the highest bone mineral density in male and female patients. The posterior region showed the lowest bone mineral density in male patients, and the anterior and posterior regions showed the lowest bone mineral density in female patients. Regions including cortex showed higher bone mineral density than pure cancellous regions in medial sides. In lateral sides, posterior regions including cortex showed highest bone mineral density with statistical significance in both male and female patients. The anterior region showed the lowest bone mineral density in both male and female patients. The mid-region of the medial side and the posterior region of the lateral side are relatively safe without cortical coverage when the component is not flush with all edges of the tibia. Cortical coverage is strongly recommended for the prevention of subsidence of the tibial component in the posterior region of the medial side, and in the anterior region of the lateral side.

Do Tibial Plateau Fractures Worsen Outcomes of Knee Ligament Injuries? A Matched Cohort Analysis

PubMed Central

Cinque, Mark E.; Godin, Jonathan A.; Moatshe, Gilbert; Chahla, Jorge; Kruckeberg, Bradley M.; Pogorzelski, Jonas; LaPrade, Robert F.

2017-01-01

Background: Tibial plateau fractures account for a small portion of all fractures; however, these fractures can pose a surgical challenge when occurring concomitantly with ligament injuries. Purpose/Hypothesis: The purpose of this study was to compare 2-year outcomes of soft tissue reconstruction with or without a concomitant tibial plateau fracture and open reduction internal fixation. We hypothesized that patients with a concomitant tibial plateau fracture at the time of soft tissue surgery would have inferior outcomes compared with patients without an associated tibial plateau fracture. Study Design: Cohort study; Level of evidence, 3. Methods: Forty patients were included in this study: 8 in the fracture group and 32 in the matched control group. Inclusion criteria for the fracture group included patients who were at least 18 years old at the time of surgery and sustained a tibial plateau fracture and a concomitant injury of the anterior cruciate ligament, posterior cruciate ligament, medial collateral ligament, or fibular collateral ligament in isolation or any combination of cruciate or collateral ligaments and who subsequently underwent isolated or combined ligament reconstruction. Patients were excluded if they underwent prior ipsilateral knee surgery, sustained additional bony injuries, or sustained an isolated extra-articular ligament injury at the time of injury. Each patient with a fracture was matched with 4 patients from a control group who had no evidence of a tibial plateau fracture but underwent the same soft tissue reconstruction procedure. Results: Patients in the fracture group improved significantly from preoperatively to postoperatively with respect to Short Form–12 (P < .05) and Western Ontario and McMaster Universities Osteoarthritis Index total scores (P < .05). The Lysholm (P = .075) and Tegner scores (P = .086) also improved, although this was not statistically significant. Patients in the control group improved significantly from preoperatively to postoperatively across all measured scores. A comparison of the postoperative results between the 2 groups showed no statistically significant difference. Conclusion: The presence of a tibial plateau fracture in conjunction with a ligamentous knee injury did not have a negative effect on postoperative patient-reported outcomes. Patient-reported outcome scores after surgery in both the fracture and control groups improved beyond the minimally clinically important difference, indicating that the presence of a fracture did not detract from the outcomes observed in patients without fractures undergoing concomitant ligament reconstruction. PMID:28840154

Electron acceleration in a secondary magnetic island formed during magnetic reconnection with a guide field

NASA Astrophysics Data System (ADS)

Wang, Huanyu; Lu, Quanming; Huang, Can; Wang, Shui

2017-05-01

Secondary magnetic islands may be generated in the vicinity of an X line during magnetic reconnection. In this paper, by performing two-dimensional (2-D) particle-in-cell simulations, we investigate the role of a secondary magnetic island in electron acceleration during magnetic reconnection with a guide field. The electron motions are found to be adiabatic, and we analyze the contributions of the parallel electric field and Fermi and betatron mechanisms to electron acceleration in the secondary island during the evolution of magnetic reconnection. When the secondary island is formed, electrons are accelerated by the parallel electric field due to the existence of the reconnection electric field in the electron current sheet. Electrons can be accelerated by both the parallel electric field and Fermi mechanism when the secondary island begins to merge with the primary magnetic island, which is formed simultaneously with the appearance of X lines. With the increase in the guide field, the contributions of the Fermi mechanism to electron acceleration become less and less important. When the guide field is sufficiently large, the contribution of the Fermi mechanism is almost negligible.

A novel electron accelerator for MRI-Linac radiotherapy.

PubMed

Whelan, Brendan; Gierman, Stephen; Holloway, Lois; Schmerge, John; Keall, Paul; Fahrig, Rebecca

2016-03-01

MRI guided radiotherapy is a rapidly growing field; however, current electron accelerators are not designed to operate in the magnetic fringe fields of MRI scanners. As such, current MRI-Linac systems require magnetic shielding, which can degrade MR image quality and limit system flexibility. The purpose of this work was to develop and test a novel medical electron accelerator concept which is inherently robust to operation within magnetic fields for in-line MRI-Linac systems. Computational simulations were utilized to model the accelerator, including the thermionic emission process, the electromagnetic fields within the accelerating structure, and resulting particle trajectories through these fields. The spatial and energy characteristics of the electron beam were quantified at the accelerator target and compared to published data for conventional accelerators. The model was then coupled to the fields from a simulated 1 T superconducting magnet and solved for cathode to isocenter distances between 1.0 and 2.4 m; the impact on the electron beam was quantified. For the zero field solution, the average current at the target was 146.3 mA, with a median energy of 5.8 MeV (interquartile spread of 0.1 MeV), and a spot size diameter of 1.5 mm full-width-tenth-maximum. Such an electron beam is suitable for therapy, comparing favorably to published data for conventional systems. The simulated accelerator showed increased robustness to operation in in-line magnetic fields, with a maximum current loss of 3% compared to 85% for a conventional system in the same magnetic fields. Computational simulations suggest that replacing conventional DC electron sources with a RF based source could be used to develop medical electron accelerators which are robust to operation in in-line magnetic fields. This would enable the development of MRI-Linac systems with no magnetic shielding around the Linac and reduce the requirements for optimization of magnetic fringe field, simplify design of the high-field magnet, and increase system flexibility.

A novel electron accelerator for MRI-Linac radiotherapy

PubMed Central

Whelan, Brendan; Gierman, Stephen; Holloway, Lois; Schmerge, John; Keall, Paul; Fahrig, Rebecca

2016-01-01

Purpose: MRI guided radiotherapy is a rapidly growing field; however, current electron accelerators are not designed to operate in the magnetic fringe fields of MRI scanners. As such, current MRI-Linac systems require magnetic shielding, which can degrade MR image quality and limit system flexibility. The purpose of this work was to develop and test a novel medical electron accelerator concept which is inherently robust to operation within magnetic fields for in-line MRI-Linac systems. Methods: Computational simulations were utilized to model the accelerator, including the thermionic emission process, the electromagnetic fields within the accelerating structure, and resulting particle trajectories through these fields. The spatial and energy characteristics of the electron beam were quantified at the accelerator target and compared to published data for conventional accelerators. The model was then coupled to the fields from a simulated 1 T superconducting magnet and solved for cathode to isocenter distances between 1.0 and 2.4 m; the impact on the electron beam was quantified. Results: For the zero field solution, the average current at the target was 146.3 mA, with a median energy of 5.8 MeV (interquartile spread of 0.1 MeV), and a spot size diameter of 1.5 mm full-width-tenth-maximum. Such an electron beam is suitable for therapy, comparing favorably to published data for conventional systems. The simulated accelerator showed increased robustness to operation in in-line magnetic fields, with a maximum current loss of 3% compared to 85% for a conventional system in the same magnetic fields. Conclusions: Computational simulations suggest that replacing conventional DC electron sources with a RF based source could be used to develop medical electron accelerators which are robust to operation in in-line magnetic fields. This would enable the development of MRI-Linac systems with no magnetic shielding around the Linac and reduce the requirements for optimization of magnetic fringe field, simplify design of the high-field magnet, and increase system flexibility. PMID:26936713

Horses and cows might teach us about human knees

NASA Astrophysics Data System (ADS)

Holland, C.; Vollrath, F.; Gill, H. S.

2014-04-01

Our comparative study of the knees of horses and cows (paraphrased as highly evolved joggers and as domesticated couch-potatoes, respectively) demonstrates significant differences in the posterior sections of bovine and equine tibial cartilage, which are consistent with specialisation for gait. These insights were possible using a novel analytical measuring technique based on the shearing of small biopsy samples, called dynamic shear analysis. We assert that this technique could provide a powerful new tool to precisely quantify the pathology of osteoarthritis for the medical field.

Beam trapping in high-current cyclic accelerators with strong-focusing fields. Memorandum report, January-December 1984

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sprangle, P.; Kapetanakos, C.A.

1985-03-06

In cyclic induction accelerators, the energy of the particles increases slowly in synchronism with the vertical (betatron) magnetic field. As a consequence of the slow acceleration, the charged particles must be confined by the weak-focusing magnetic field over long periods of time, and thus field errors, instabilities, and radiation losses can impose limitations on the acceleration process. These limitations can be substantially relaxed if the acceleration were to occur rapidly, say over a few microseconds. An appropriate name for such an accelerator is REBA-TRON (Rapid Electron Beam Accelerator). This paper considers a possible mechanism which could trap a high currentmore » electron beam in the strong focusing magnetic fields of the rebatron. We investigate a possible mechanism for trapping an intense relativistic electron beam confined by strong focusing fields. In our model the electron beam is assumed to be injected into torsatron fields off axis, near the chamber walls. The finite resistivity of the walls results in a drag force on the beam centroid which may cause the beam to spiral inward towards the axis of the chamber. We have analyzed this mechanism and obtained decay rates for the inward spiraling beam motion.« less

Synchronous acceleration with tapered dielectric-lined waveguides

NASA Astrophysics Data System (ADS)

Lemery, F.; Floettmann, K.; Piot, P.; Kärtner, F. X.; Aßmann, R.

2018-05-01

We present a general concept to accelerate nonrelativistic charged particles. Our concept employs an adiabatically-tapered dielectric-lined waveguide which supports accelerating phase velocities for synchronous acceleration. We propose an ansatz for the transient field equations, show it satisfies Maxwell's equations under an adiabatic approximation and find excellent agreement with a finite-difference time-domain computer simulation. The fields were implemented into the particle-tracking program astra and we present beam dynamics results for an accelerating field with a 1-mm-wavelength and peak electric field of 100 MV /m . Numerical simulations indicate that a ˜200 -keV electron beam can be accelerated to an energy of ˜10 MeV over ˜10 cm with parameters of interest to a wide range of applications including, e.g., future advanced accelerators, and ultra-fast electron diffraction.

Component alignment in revision total knee arthroplasty using diaphyseal engaging modular offset press-fit stems.

PubMed

Nakasone, Cass K; Abdeen, Ayesha; Khachatourians, Armond G; Sugimori, Tanzo; Vince, Kelly G

2008-12-01

We performed a retrospective study of the radiographic position of femoral and tibial components in a series of revision total knee arthroplasties using diaphyseal-engaging, press fit, modular stems. Fifty-two consecutive revision cases were performed. Femoral and tibial component alignment was measured preoperatively and postoperatively. The canal-filling ratio was measured and correlated with anatomic alignment. There was a trend toward improved alignment with increasing canal fill, suggesting that uncemented diaphyseal engaging press-fit modular stems facilitate accurate alignment for both femoral and tibial components in revision surgery.

Atypical presentation of popliteal artery entrapment syndrome: involvement of the anterior tibial artery.

PubMed

Bou, Steven; Day, Carly

2014-11-01

Popliteal artery entrapment syndrome (PAES) is a rare condition that should be suspected in a young patient with exertional lower extremity pain. We report the case of an 18-year-old female volleyball player with bilateral exertional lower extremity pain who had been previously diagnosed with tendinitis and periostitis. Diagnostic studies showed entrapment of the left popliteal artery and the left anterior tibial artery. To our knowledge, there has only been 1 previous report of anterior tibial artery involvement in PAES. Copyright © 2014 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Long-term anabolic effects of prostaglandin-E2 on tibial diaphyseal bone in male rats

NASA Technical Reports Server (NTRS)

Jee, Webster S. S.; Ke, Hua Zhu; Li, Xiao Jian

1991-01-01

The effects of long-term prostaglandin E2 (PGE2) on tibial diaphyseal bone were studied in 7-month-old male Sprague-Dawley rats given daily subcutaneous injections of 0, 1, 3 and 6 mg PGE2/kg/day for 60, 120 and 180 days. The tibial shaft was measured by single photon absorptiometry and dynamic histomorphometric analyses were performed on double-fluorescent labeled undecalcified tibial diaphyseal bone samples. Exogenous PGE2 administration produced the following transient changes in a dose-response manner between zero and 60 days: (1) increased bone width and mineral density; (2) increased total tissue and total bone areas; (3) decreased marrow area; (4) increased periosteal and corticoendosteal lamellar bone formation; (5) activated corticoendosteal lamellar and woven trabecular bone formation; and (6) activated intracortical bone remodeling. A new steady-state of increased tibial diaphyseal bone mass and elevated bone activities were observed from day 60 onward. The elevated bone mass level attained after 60 days of PGE2 treatment was maintained at 120 and 180 days. These observations indicate that the powerful anabolic effects of PGE2 will increase both periosteal and corticoendosteal bone mass and sustain the transient increase in bone mass with continuous daily administration of PGE2.

Cemented total knee replacement in 24 dogs: surgical technique, clinical results, and complications.

PubMed

Allen, Matthew J; Leone, Kendall A; Lamonte, Kimberly; Townsend, Katy L; Mann, Kenneth A

2009-07-01

To characterize the performance of cemented total knee replacement (TKR) in dogs. Preclinical research study. Skeletally mature, male Hounds (25-30 kg; n=24) with no preexisting joint pathology. Dogs had unilateral cemented TKR and were evaluated at 6, 12, 26, or 52 weeks (6 dogs/time point) by radiography, bone density analysis, visual gait assessment, and direct measurement of thigh circumference and stifle joint range of motion as indicators of functional recovery. At study end, the stability of the cemented tibial component was determined by destructive mechanical testing. Joint stability was excellent in 16 dogs (67%) and good in 8 dogs. None of the tibial components had evidence of migration or periprosthetic osteolysis whereas 1 femoral component was loose at 52 weeks. There was an early and significant decrease in tibial bone density, likely because of disuse of the operated limb. Dogs returned to full activity by 12 weeks. The tibial cement-bone interface maintained its strength over 52 weeks. Cement provides stable fixation of the tibial component in canine TKR. Cemented TKR yields adequate clinical function and stifle joint excursion in the dog. Clinical studies are needed to determine the long-term fate of cemented TKR implants, to assess the influence of implant design on implant fixation and wear, and to obtain objective functional data.

Association between foot type and tibial stress injuries: a systematic review.

PubMed

Barnes, A; Wheat, J; Milner, C

2008-02-01

To systematically review published articles investigating the association between structural foot characteristics and tibial stress injuries, and to suggest possible future avenues of research in this area. Literature was identified, selected and appraised in accordance with the methods of a systematic review. Articles potentially relevant to the research question were identified by searching the following electronic databases: Amed, Cinahl, Index to UK theses, Medline, PubMed, Scopus, Sports discus and Web of science. Duplicates were removed and, based on the title and abstract, the full text of relevant studies were retrieved. Two reviewers independently assessed papers; this formed the basis for the inclusion of the most appropriate trials. From the 479 articles originally identified, nine were deemed appropriate for inclusion in the review. In general, specific data relating to this relationship was limited. Outcomes of the nine investigations were difficult to compare due to differing methods used across studies. Results have proved conflicting, with limited evidence found to implicate any specific foot type as a potential risk factor for tibial stress injuries. No definitive conclusions can be drawn relating foot structure or function to an increased risk of tibial stress injuries. Extremes of foot types are likely to pose an increased risk of tibial stress injuries compared to normal arched feet.

Combustion in an acceleration field: A survey of Soviet literature

NASA Technical Reports Server (NTRS)

Radloff, S. J.; Osborn, J. R.

1980-01-01

The effect of an acceleration field on the burning rate of a solid propellant was measured from -900g's to +1000g's using both double base and ammonium perchlorate based propellants. The acceleration fields were simulated using a centrifuge device and the burning rate was recorded. Both metalized and non-metalized variations of each propellant were tested and it was found that acceleration fields affect the burning rate. For the most part the theoretical predictions and the experimental results agreed.

Predictors of failure and success of tibial interventions for critical limb ischemia.

PubMed

Fernandez, Nathan; McEnaney, Ryan; Marone, Luke K; Rhee, Robert Y; Leers, Steven; Makaroun, Michel; Chaer, Rabih A

2010-10-01

The efficacy of tibial artery endovascular intervention (TAEI) for critical limb ischemia (CLI) and particularly for wound healing is not fully defined. The purpose of this study is to determine predictors of failure and success for TAEI in the setting of CLI. All TAEI for tissue loss or rest pain (Rutherford classes 4, 5, and 6) from 2004 to 2008 were retrospectively reviewed. Clinical outcomes and patency rates were analyzed by multivariable Cox proportional hazards regression and life table analysis. One hundred twenty-three limbs in 111 patients (62% male, mean age 74) were treated. Sixty-seven percent of patients were diabetics, 55% had renal insufficiency, and 21% required hemodialysis. One hundred two limbs (83%) exhibited tissue loss; all others had ischemic rest pain. All patients underwent tibial angioplasty (PTA). Tibial excimer laser atherectomy was performed in 14% of the patients. Interventions were performed on multiple tibial vessels in 20% of limbs. Isolated tibial procedures were performed on 50 limbs (41%), while 73 patients had concurrent ipsilateral superficial femoral artery or popliteal interventions. The mean distal popliteal and tibial runoff score improved from 11.8 ± 3.6 to 6.7 ± 1.6 (P < .001), and the mean ankle-brachial index increased from 0.61 ± 0.26 to 0.85 ± 0.22 (P < .001). Surgical bypass was required in seven patients (6%). The mean follow up was 6.8 ± 6.6 months, while the 1-year primary, primary-assisted, and secondary patency rates were 33%, 50%, and 56% respectively. Limb salvage rate at 1 year was 75%. Factors found to be associated with impaired limb salvage included renal insufficiency (hazard ratio [HR] = 5.7; P = .03) and the need for pedal intervention (HR = 13.75; P = .04). TAEI in an isolated peroneal artery (odds ratio = 7.80; P = .01) was associated with impaired wound healing, whereas multilevel intervention (HR = 2.1; P = .009) and tibial laser atherectomy (HR = 3.1; P = .01) were predictors of wound healing. In patients with tissue loss, 41% achieved complete closure (mean time to healing, 10.7 ± 7.4 months), and 39% exhibited partial wound healing (mean follow up, 4.4 ± 4.8 months) at last follow up. Diabetes, smoking, statin therapy, and revascularization of > 1 tibial vessel had no impact on limb salvage or wound healing. Re-intervention rate was 50% at 1 year. TAEI is an effective treatment for CLI with acceptable limb salvage and wound healing rates, but requires a high rate of reintervention. Patients with renal failure, pedal disease, or isolated peroneal runoff have poor outcomes with TAEI and should be considered for surgical bypass. Copyright © 2010 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

Revolutionizing orthopaedic biomaterials: The potential of biodegradable and bioresorbable magnesium-based materials for functional tissue engineering

PubMed Central

Farraro, Kathryn F.; Kim, Kwang E.; Woo, Savio L-Y.; Flowers, Jonquil R.; McCullough, Matthew B.

2014-01-01

In recent years, there has been a surge of interest in magnesium (Mg) and its alloys as biomaterials for orthopaedic applications, as they possess desirable mechanical properties, good biocompatibility, and biodegradability. Also shown to be osteoinductive, Mg-based materials could be particularly advantageous in functional tissue engineering to improve healing and serve as scaffolds for delivery of drugs, cells, and cytokines. In this paper, we will present two examples of Mg-based orthopaedic devices: an interference screw to accelerate ACL graft healing and a ring to aid in the healing of an injured ACL. In vitro tests using a robotic/UFS testing system showed that both devices could restore function of the goat stifle joint. Under a 67-N anterior tibial load, both the ACL graft fixed with the Mg-based interference screw and the Mg-based ring-repaired ACL could restore anterior tibial translation (ATT) to within 2 mm and 5 mm, respectively, of the intact joint at 301, 601, and 901 of flexion. In-situ forces in the replacement graft and Mg-based ring-repaired ACL were also similar to those of the intact ACL. Further, early in vivo data using the Mg-based interference screw showed that after 12 weeks, it was non-toxic and the joint stability and graft function reached similar levels as published data. Following these positive results, we will move forward in incorporating bioactive molecules and ECM bioscaffolds to these Mg-based biomaterials to test their potential for functional tissue engineering of musculoskeletal and other tissues. PMID:24373510

Revolutionizing orthopaedic biomaterials: The potential of biodegradable and bioresorbable magnesium-based materials for functional tissue engineering.

PubMed

Farraro, Kathryn F; Kim, Kwang E; Woo, Savio L-Y; Flowers, Jonquil R; McCullough, Matthew B

2014-06-27

In recent years, there has been a surge of interest in magnesium (Mg) and its alloys as biomaterials for orthopaedic applications, as they possess desirable mechanical properties, good biocompatibility, and biodegradability. Also shown to be osteoinductive, Mg-based materials could be particularly advantageous in functional tissue engineering to improve healing and serve as scaffolds for delivery of drugs, cells, and cytokines. In this paper, we will present two examples of Mg-based orthopaedic devices: an interference screw to accelerate ACL graft healing and a ring to aid in the healing of an injured ACL. In vitro tests using a robotic/UFS testing system showed that both devices could restore function of the goat stifle joint. Under a 67-N anterior tibial load, both the ACL graft fixed with the Mg-based interference screw and the Mg-based ring-repaired ACL could restore anterior tibial translation (ATT) to within 2mm and 5mm, respectively, of the intact joint at 30°, 60°, and 90° of flexion. In-situ forces in the replacement graft and Mg-based ring-repaired ACL were also similar to those of the intact ACL. Further, early in vivo data using the Mg-based interference screw showed that after 12 weeks, it was non-toxic and the joint stability and graft function reached similar levels as published data. Following these positive results, we will move forward in incorporating bioactive molecules and ECM bioscaffolds to these Mg-based biomaterials to test their potential for functional tissue engineering of musculoskeletal and other tissues. © 2013 Published by Elsevier Ltd.

Thermo-magnetic instabilities in Nb 3Sn superconducting accelerator magnets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bordini, Bernardo

2006-09-01

The advance of High Energy Physics research using circulating accelerators strongly depends on increasing the magnetic bending field which accelerator magnets provide. To achieve high fields, the most powerful present-day accelerator magnets employ NbTi superconducting technology; however, with the start up of Large Hadron Collider (LHC) in 2007, NbTi magnets will have reached the maximum field allowed by the intrinsic properties of this superconductor. A further increase of the field strength necessarily requires a change in superconductor material; the best candidate is Nb 3Sn. Several laboratories in the US and Europe are currently working on developing Nb 3Sn accelerator magnets,more » and although these magnets have great potential, it is suspected that their performance may be fundamentally limited by conductor thermo-magnetic instabilities: an idea first proposed by the Fermilab High Field Magnet group early in 2003. This thesis presents a study of thermo-magnetic instability in high field Nb 3Sn accelerator magnets. In this chapter the following topics are described: the role of superconducting magnets in High Energy Physics; the main characteristics of superconductors for accelerator magnets; typical measurements of current capability in superconducting strands; the properties of Nb 3Sn; a description of the manufacturing process of Nb 3Sn strands; superconducting cables; a typical layout of superconducting accelerator magnets; the current state of the art of Nb 3Sn accelerator magnets; the High Field Magnet program at Fermilab; and the scope of the thesis.« less

The Anterolateral Capsule of the Knee Behaves Like a Sheet of Fibrous Tissue.

PubMed

Guenther, Daniel; Rahnemai-Azar, Amir A; Bell, Kevin M; Irarrázaval, Sebastián; Fu, Freddie H; Musahl, Volker; Debski, Richard E

2017-03-01

The function of the anterolateral capsule of the knee has not been clearly defined. However, the contribution of this region of the capsule to knee stability in comparison with other anterolateral structures can be determined by the relative force that each structure carries during loading of the knee. Purpose/Hypothesis: The purpose of this study was to determine the forces in the anterolateral structures of the intact and anterior cruciate ligament (ACL)-deficient knee in response to an anterior tibial load and internal tibial torque. It was hypothesized that the anterolateral capsule would not function like a traditional ligament (ie, transmitting forces only along its longitudinal axis). Controlled laboratory study. Loads (134-N anterior tibial load and 7-N·m internal tibial torque) were applied continuously during flexion to 7 fresh-frozen cadaveric knees in the intact and ACL-deficient state using a robotic testing system. The lateral collateral ligament (LCL) and the anterolateral capsule were separated from the surrounding tissue and from each other. This was done by performing 3 vertical incisions: lateral to the LCL, medial to the LCL, and lateral to the Gerdy tubercle. Attachments of the LCL and anterolateral capsule were detached from the underlying tissue (ie, meniscus), leaving the insertions and origins intact. The force distribution in the anterolateral capsule, ACL, and LCL was then determined at 30°, 60°, and 90° of knee flexion using the principle of superposition. In the intact knee, the force in the ACL in response to an anterior tibial load was greater than that in the other structures ( P < .001). However, in response to an internal tibial torque, no significant differences were found between the ACL, LCL, and forces transmitted between each region of the anterolateral capsule after capsule separation. The anterolateral capsule experienced smaller forces (~50% less) compared with the other structures ( P = .048). For the ACL-deficient knee in response to an anterior tibial load, the force transmitted between each region of the anterolateral capsule was 434% greater than was the force in the anterolateral capsule ( P < .001) and 54% greater than the force in the LCL ( P = .036) at 30° of flexion. In response to an internal tibial torque at 30°, 60°, or 90° of knee flexion, no significant differences were found between the force transmitted between each region of the anterolateral capsule and the LCL. The force in the anterolateral capsule was significantly smaller than that in the other structures at all knee flexion angles for both loading conditions ( P = .004 for anterior tibial load and P = .04 for internal tibial torque). The anterolateral capsule carries negligible forces in the longitudinal direction, and the forces transmitted between regions of the capsule were similar to the forces carried by the other structures at the knee, suggesting that it does not function as a traditional ligament. Thus, the anterolateral capsule should be considered a sheet of tissue. Surgical repair techniques for the anterolateral capsule should restore the ability of the tissue to transmit forces between adjacent regions of the capsule rather than along its longitudinal axis.

ELECTRON ACCELERATION BY CASCADING RECONNECTION IN THE SOLAR CORONA. II. RESISTIVE ELECTRIC FIELD EFFECTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, X.; Gan, W.; Liu, S.

We investigate electron acceleration by electric fields induced by cascading reconnections in current sheets trailing coronal mass ejections via a test particle approach in the framework of the guiding-center approximation. Although the resistive electric field is much weaker than the inductive electric field, the electron acceleration is still dominated by the former. Anomalous resistivity η is switched on only in regions where the current carrier’s drift velocity is large enough. As a consequence, electron acceleration is very sensitive to the spatial distribution of the resistive electric fields, and electrons accelerated in different segments of the current sheet have different characteristics.more » Due to the geometry of the 2.5-dimensional electromagnetic fields and strong resistive electric field accelerations, accelerated high-energy electrons can be trapped in the corona, precipitating into the chromosphere or escaping into interplanetary space. The trapped and precipitating electrons can reach a few MeV within 1 s and have a very hard energy distribution. Spatial structure of the acceleration sites may also introduce breaks in the electron energy distribution. Most of the interplanetary electrons reach hundreds of keV with a softer distribution. To compare with observations of solar flares and electrons in solar energetic particle events, we derive hard X-ray spectra produced by the trapped and precipitating electrons, fluxes of the precipitating and interplanetary electrons, and electron spatial distributions.« less

Modeling magnetic field amplification in nonlinear diffusive shock acceleration

NASA Astrophysics Data System (ADS)

Vladimirov, Andrey

2009-02-01

This research was motivated by the recent observations indicating very strong magnetic fields at some supernova remnant shocks, which suggests in-situ generation of magnetic turbulence. The dissertation presents a numerical model of collisionless shocks with strong amplification of stochastic magnetic fields, self-consistently coupled to efficient shock acceleration of charged particles. Based on a Monte Carlo simulation of particle transport and acceleration in nonlinear shocks, the model describes magnetic field amplification using the state-of-the-art analytic models of instabilities in magnetized plasmas in the presence of non-thermal particle streaming. The results help one understand the complex nonlinear connections between the thermal plasma, the accelerated particles and the stochastic magnetic fields in strong collisionless shocks. Also, predictions regarding the efficiency of particle acceleration and magnetic field amplification, the impact of magnetic field amplification on the maximum energy of accelerated particles, and the compression and heating of the thermal plasma by the shocks are presented. Particle distribution functions and turbulence spectra derived with this model can be used to calculate the emission of observable nonthermal radiation.

Particle Acceleration, Magnetic Field Generation in Relativistic Shocks

NASA Technical Reports Server (NTRS)

Nishikawa, Ken-Ichi; Hardee, P.; Hededal, C. B.; Richardson, G.; Sol, H.; Preece, R.; Fishman, G. J.

2005-01-01

Shock acceleration is an ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. Using a 3-D relativistic electromagnetic particle (REMP) code, we have investigated particle acceleration associated with a relativistic jet front propagating through an ambient plasma with and without initial magnetic fields. We find only small differences in the results between no ambient and weak ambient parallel magnetic fields. Simulations show that the Weibel instability created in the collisionless shock front accelerates particles perpendicular and parallel to the jet propagation direction. New simulations with an ambient perpendicular magnetic field show the strong interaction between the relativistic jet and the magnetic fields. The magnetic fields are piled up by the jet and the jet electrons are bent, which creates currents and displacement currents. At the nonlinear stage, the magnetic fields are reversed by the current and the reconnection may take place. Due to these dynamics the jet and ambient electron are strongly accelerated in both parallel and perpendicular directions.

Particle Acceleration, Magnetic Field Generation, and Emission in Relativistic Shocks

NASA Technical Reports Server (NTRS)

Nishikawa, Ken-IchiI.; Hededal, C.; Hardee, P.; Richardson, G.; Preece, R.; Sol, H.; Fishman, G.

2004-01-01

Shock acceleration is an ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. Using a 3-D relativistic electromagnetic particle (m) code, we have investigated particle acceleration associated with a relativistic jet front propagating through an ambient plasma with and without initial magnetic fields. We find only small differences in the results between no ambient and weak ambient parallel magnetic fields. Simulations show that the Weibel instability created in the collisionless shock front accelerates particles perpendicular and parallel to the jet propagation direction. New simulations with an ambient perpendicular magnetic field show the strong interaction between the relativistic jet and the magnetic fields. The magnetic fields are piled up by the jet and the jet electrons are bent, which creates currents and displacement currents. At the nonlinear stage, the magnetic fields are reversed by the current and the reconnection may take place. Due to these dynamics the jet and ambient electron are strongly accelerated in both parallel and perpendicular directions.

Flow-Through Free Fibula Osteocutaneous Flap in Reconstruction of Tibial Bone, Soft Tissue, and Main Artery Segmental Defects.

PubMed

Li, Zonghuan; Yu, Aixi; Qi, Baiwen; Pan, Zhenyu; Ding, Junhui

2017-08-01

The aim of this report was to present the use of flow-through free fibula osteocutaneous flap for the repair of complex tibial bone, soft tissue, and main artery segmental defects. Five patients with bone, soft tissue, and segmental anterior tibial artery defects were included. The lengths of injured tibial bones ranged from 4 to 7 cm. The sizes of impaired soft tissues were between 9 × 4 and 15 × 6 cm. The lengths of defect of anterior tibial artery segments ranged from 6 to 10 cm. Two patients had distal limb perfusion problems. Flow-through free fibula osteocutaneous flap was performed for all 5 patients. Patients were followed for 12 to 18 months. All wounds healed after 1-stage operation, and all flow-through flaps survived. The distal perfusion after vascular repair was normal in all patients. Superficial necrosis of flap edge was noted in 1 case. After the local debridement and partial thickness skin graft, the flap healed uneventfully, and the surgical operation did not increase injury to the donor site. Satisfactory bone union was achieved in all patients in 2 to 4 months postoperation. Enlargement of fibula graft was observed during follow-up from 12 to 18 months. The functions of adjacent joints were recovered, and all patients were able to walk normally. Flow-through free fibula osteocutaneous flap was shown to be an effective and efficient technique for repairing composite tibial bone, soft tissue, and main artery segmental defects. This 1-stage operation should be useful in clinical practice for the treatment of complex bone, soft tissue, and vessel defects.

Surgical treatment of refractory tibial stress fractures in elite dancers: a case series.

PubMed

Miyamoto, Ryan G; Dhotar, Herman S; Rose, Donald J; Egol, Kenneth

2009-06-01

Treatment of tibial stress fractures in elite dancers is centered on rest and activity modification. Surgical intervention in refractory cases has important implications affecting the dancers' careers. Refractory tibial stress fractures in dancers can be treated successfully with drilling and bone grafting or intramedullary nailing. Case series; Level of evidence, 4. Between 1992 and 2006, 1757 dancers were evaluated at a dance medicine clinic; 24 dancers (1.4%) had 31 tibial stress fractures. Of that subset, 7 (29.2%) elite dancers with 8 tibial stress fractures were treated operatively with either intramedullary nailing or drilling and bone grafting. Six of the patients were followed up closely until they were able to return to dance. One patient was available only for follow-up phone interview. Data concerning their preoperative treatment regimens, operative procedures, clinical union, radiographic union, and time until return to dance were recorded and analyzed. The mean age of the surgical patients at the time of stress fracture was 22.6 years. The mean duration of preoperative symptoms before surgical intervention was 25.8 months. Four of the dancers were male and 3 were female. All had failed nonoperative treatment regimens. Five patients (5 tibias) underwent drilling and bone grafting of the lesion, and 2 patients (3 tibias) with completed fractures or multiple refractory stress fractures underwent intramedullary nailing. Clinical union was achieved at a mean of 6 weeks and radiographic union at 5.1 months. Return to full dance activity was at an average of 6.5 months postoperatively. Surgical intervention for tibial stress fractures in dancers who have not responded to nonoperative management allowed for resolution of symptoms and return to dancing with minimal morbidity.

What Preoperative Radiographic Parameters Are Associated With Increased Medial Release in Total Knee Arthroplasty?

PubMed

Martin, J Ryan; Jennings, Jason M; Levy, Daniel L; Watters, Tyler Steven; Miner, Todd M; Dennis, Douglas A

2017-03-01

Preoperative varus deformity of the knee is a common malalignment in patients undergoing primary total knee arthroplasty (TKA). We are unaware of any studies that have correlated how various preoperative radiographic parameters can predict the amount of medial releases performed to achieve optimal coronal alignment and ligamentous balance. A retrospective review was performed on 67 patients who required at least a medial tibial reduction osteotomy (MTRO) during primary TKA to achieve coronal balance. This patient population was matched 1:1 to another cohort of TKA patients by age, gender, and body mass index who did not require an MTRO. A radiographic evaluation was used to compare the 2 cohorts. Preoperatively, the MTRO cohort was noted to have significantly increased varus tibiofemoral (86.12° vs 93.43°), tibial articular surface (85.79° vs 87.54°), and medial tibial articular surface angles (75.22° vs 85.34°) compared to the control cohort. The MTRO cohort had 3.13 mm of medial tibial offset and 9.06 mm of lateral joint space opening and the control cohort had 0.09 mm and 4.07 mm, respectively. The medial tibial articular surface angle and lateral joint space widening were statistically associated with the MTRO cohort. The final tibiofemoral angle in the MTRO cohort was 92.43° and was 93.40° in the control cohort. The MTRO cohort was noted to have several preoperative radiographic parameters that were significantly different than the control cohort. However, the medial tibial articular surface angle and lateral joint space widening were the only radiographic parameters that were statistically associated with requiring an MTRO. Copyright © 2016 Elsevier Inc. All rights reserved.

The Effect of Graft Strength on Knee Laxity and Graft In-Situ Forces after Posterior Cruciate Ligament Reconstruction

PubMed Central

Lai, Yu-Shu; Chen, Wen-Chuan; Huang, Chang-Hung; Cheng, Cheng-Kung; Chan, Kam-Kong; Chang, Ting-Kuo

2015-01-01

Surgical reconstruction is generally recommended for posterior cruciate ligament (PCL) injuries; however, the use of grafts is still a controversial problem. In this study, a three-dimensional finite element model of the human tibiofemoral joint with articular cartilage layers, menisci, and four main ligaments was constructed to investigate the effects of graft strengths on knee kinematics and in-situ forces of PCL grafts. Nine different graft strengths with stiffness ranging from 0% (PCL rupture) to 200%, in increments of 25%, of an intact PCL’s strength were used to simulate the PCL reconstruction. A 100 N posterior tibial drawer load was applied to the knee joint at full extension. Results revealed that the maximum posterior translation of the PCL rupture model (0% stiffness) was 6.77 mm in the medial compartment, which resulted in tibial internal rotation of about 3.01°. After PCL reconstruction with any graft strength, the laxity of the medial tibial compartment was noticeably improved. Tibial translation and rotation were similar to the intact knee after PCL reconstruction with graft strengths ranging from 75% to 125% of an intact PCL. When the graft’s strength surpassed 150%, the medial tibia moved forward and external tibial rotation greatly increased. The in-situ forces generated in the PCL grafts ranged from 13.15 N to 75.82 N, depending on the stiffness. In conclusion, the strength of PCL grafts have has a noticeable effect on anterior-posterior translation of the medial tibial compartment and its in-situ force. Similar kinematic response may happen in the models when the PCL graft’s strength lies between 75% and 125% of an intact PCL. PMID:26001045

Distal tibial tuberosity translation using TTA implants for the treatment of patella alta in large breed dogs. Surgical technique and clinical outcome.

PubMed

Pugliese, L C; Pike, F S; Aiken, S W

2015-01-01

Medial patellar luxation frequently occurs in dogs resulting in lameness with increasing incidence in large breed dogs. Patella alta has been defined as a patellar ligament length to patellar length ratio that is greater than two and may predispose to patellar luxation. To describe the surgical technique for stabilization of the distal translation of the tibial tuberosity using tibial tuberosity advancement plates and the clinical outcomes with follow-up for clinical cases of dogs. Dogs that were presented with the complaint of patellar luxation and that were concurrently diagnosed with patella alta and were greater than 20 kg in body weight underwent surgery using a tibial tuberosity advancement plate to stabilize the osteotomy. Radiographic assessment of A:PL distance (the ratio of the proximal aspect of the patella to the femoral condyle [A] to the patellar length [PL]), L:P ratio (ratio of the length of the patellar ligament to the diagonal length of the patella), and owner assessment were obtained. Eleven stifles in nine dogs underwent surgical correction with a mean preoperative L:P ratio of 2.47. There were no complications and the lameness resolved clinically. The mean A:PL ratios preoperatively (2.6 ± 0.22) and postoperatively (2.1 ± 0.25) were significantly different (p = 0.0003). All owners were satisfied with the outcome and all dogs had a resolution of lameness with no recurrence of patellar luxation. Stabilization of distal translation of the tibial tuberosity using tibial tuberosity advancement implants to correct patella alta in large breed dogs was feasible and resulted in good clinical outcome.

Tibial lengthening over intramedullary nails

PubMed Central

Burghardt, R. D.; Manzotti, A.; Bhave, A.; Paley, D.

2016-01-01

Objectives The purpose of this study was to compare the results and complications of tibial lengthening over an intramedullary nail with treatment using the traditional Ilizarov method. Methods In this matched case study, 16 adult patients underwent 19 tibial lengthening over nails (LON) procedures. For the matched case group, 17 patients who underwent 19 Ilizarov tibial lengthenings were retrospectively matched to the LON group. Results The mean external fixation time for the LON group was 2.6 months and for the matched case group was 7.6 months. The mean lengthening amounts for the LON and the matched case groups were 5.2 cm and 4.9 cm, respectively. The radiographic consolidation time in the LON group was 6.6 months and in the matched case group 7.6 months. Using a clinical and radiographic outcome score that was designed for this study, the outcome was determined to be excellent in 17 and good in two patients for the LON group. The outcome was excellent in 14 and good in five patients in the matched case group. The LON group had increased blood loss and increased cost. The LON group had four deep infections; the matched case group did not have any deep infections. Conclusions The outcomes in the LON group were comparable with the outcomes in the matched case group. The LON group had a shorter external fixation time but experienced increased blood loss, increased cost, and four cases of deep infection. The advantage of reducing external fixation treatment time may outweigh these disadvantages in patients who have a healthy soft-tissue envelope. Cite this article: J. E. Herzenberg. Tibial lengthening over intramedullary nails: A matched case comparison with Ilizarov tibial lengthening. Bone Joint Res 2016;5:1–10. doi: 10.1302/2046-3758.51.2000577 PMID:26764351

Post-Cam Design and Contact Stress on Tibial Posts in Posterior-Stabilized Total Knee Prostheses: Comparison Between a Rounded and a Squared Design.

PubMed

Watanabe, Toshifumi; Koga, Hideyuki; Horie, Masafumi; Katagiri, Hiroki; Sekiya, Ichiro; Muneta, Takeshi

2017-12-01

The post-cam mechanism in posterior stabilized (PS) prostheses plays an important role in total knee arthroplasty (TKA). The purpose of this study is to clarify the difference of the contact stress on the tibial post between a rounded post-cam design and a squared design during deep knee flexion and at hyperextension using the three-dimensional (3D) finite element models. We created 2 types of 3D, finite element models of PS prostheses (types A and B), whose surfaces were identical except for the post-cam geometries: type A has a rounded post-cam design, while type B has a squared design. Both types have a similar curved-shape intercondylar notch of the femoral component. Stress distributions, peak contact stresses, and contact areas on the tibial posts at 90°, 120°, and 150° flexion with/without 10° tibial internal rotation and at 10° hyperextension were compared between the 2 models. Type B demonstrated more concentrated stress distribution compared to type A. The peak contact stresses were similar in both groups during neutral flexion; however, the stresses were much higher in type B during flexion with 10° rotation and at hyperextension. The higher peak contact stresses corresponded to the smaller contact areas in the tibial post. A rounded post-cam design demonstrated less stress concentration during flexion with rotation and at hyperextension compared with a squared design. The results would be useful for development of implant designs and prediction of the contact stress on the tibial post in PS total knee arthroplasty. Copyright © 2017 Elsevier Inc. All rights reserved.

Association of baseline knee bone size, cartilage volume, and body mass index with knee cartilage loss over time: a longitudinal study in younger or middle-aged adults.

PubMed

Antony, Benny; Ding, Changhai; Stannus, Oliver; Cicuttini, Flavia; Jones, Graeme

2011-09-01

To determine the association of knee bone size, cartilage volume, and body mass index (BMI) at baseline with knee cartilage loss over 2 years in younger or middle-aged adults. A total of 324 subjects (mean age 45 yrs, range 26-61) were measured at baseline and about 2 years later. Knee cartilage volume and bone size were determined using T1-weighted fat-saturated magnetic resonance imaging. In multivariable analysis, baseline knee bone size was negatively associated with annual change in knee cartilage volume at medial and lateral tibial sites (ß = -0.62% to -0.47%/cm(2), all p < 0.001). The associations disappeared at medial tibial site after adjustment for baseline cartilage volume and became of borderline statistical significance at lateral tibial site after adjustment for both baseline cartilage volume and osteophytes (ß = -0.29, p = 0.059). Baseline knee cartilage volume was consistently and negatively associated with annual change in knee cartilage volume at all 3 medial tibial, lateral tibial, and patellar sites (ß = -4.41% to -1.37%/ml, all p < 0.001). Baseline BMI was negatively associated with an annual change in knee cartilage volume, but only in subjects within the upper tertile of baseline cartilage volume, even after adjusting for cartilage defects (ß = -0.16% to -0.34%/kg/m(2), all p < 0.05). Our study suggests that both higher baseline tibial bone area and knee cartilage volume (most likely due to cartilage swelling) are associated with greater knee cartilage loss over 2 years. A higher BMI was associated with greater knee cartilage loss only in subjects with higher baseline cartilage volume.

Relationship between tibial spine size and the occurrence of osteochondritis dissecans: an argument in favour of the impingement theory.

PubMed

Cavaignac, Etienne; Perroncel, Geoffroy; Thépaut, Mathias; Vial, Julie; Accadbled, Franck; De Gauzy, Jérôme Sales

2017-08-01

Pathophysiology of osteochondritis dissecans (OCD) of the medial femoral condyle remains uncertain. Specifically, the relationship between the size of the anterior tibial spine (ATS) and the presence of OCD has not been explored. The purpose of this study was to evaluate the relationship between ATS size and the occurrence of OCD. Seventy-nine children between 8 and 17 years of age were included in two groups: OCD (n = 37) and control (n = 42). The groups were matched in terms of age, gender, BMI and weight. Two independent observers performed an MRI analysis of the size of the tibial spine and intercondylar notch relative to the size of the respective epiphyses. For this study, the "S ratio" was calculated by dividing the height of the tibial spine by the height of the tibial epiphysis. The "N ratio" was calculated by dividing the height of the notch by the height of the femoral epiphysis. These two ratios for both groups were compared using Student's t test. The mean value of the S ratio in the OCD group was 0.39 ± 0.06; the mean value of the S ratio in the control group was 0.32 ± 0.03 (P = 0.004). The mean value of the N ratio in the OCD group was 0.70 ± 0.08; the mean value of the N ratio in the control group was 0.70 ± 0.07 (n.s.). This study's findings confirm our hypothesis that patients with OCD have a more prominent tibial spine than in patients without OCD. IV.

A modified technique to reduce tibial keel cutting errors during an Oxford unicompartmental knee arthroplasty.

PubMed

Inui, Hiroshi; Taketomi, Shuji; Tahara, Keitarou; Yamagami, Ryota; Sanada, Takaki; Tanaka, Sakae

2017-03-01

Bone cutting errors can cause malalignment of unicompartmental knee arthroplasties (UKA). Although the extent of tibial malalignment due to horizontal cutting errors has been well reported, there is a lack of studies evaluating malalignment as a consequence of keel cutting errors, particularly in the Oxford UKA. The purpose of this study was to examine keel cutting errors during Oxford UKA placement using a navigation system and to clarify whether two different tibial keel cutting techniques would have different error rates. The alignment of the tibial cut surface after a horizontal osteotomy and the surface of the tibial trial component was measured with a navigation system. Cutting error was defined as the angular difference between these measurements. The following two techniques were used: the standard "pushing" technique in 83 patients (group P) and a modified "dolphin" technique in 41 patients (group D). In all 123 patients studied, the mean absolute keel cutting error was 1.7° and 1.4° in the coronal and sagittal planes, respectively. In group P, there were 22 outlier patients (27 %) in the coronal plane and 13 (16 %) in the sagittal plane. Group D had three outlier patients (8 %) in the coronal plane and none (0 %) in the sagittal plane. Significant differences were observed in the outlier ratio of these techniques in both the sagittal (P = 0.014) and coronal (P = 0.008) planes. Our study demonstrated overall keel cutting errors of 1.7° in the coronal plane and 1.4° in the sagittal plane. The "dolphin" technique was found to significantly reduce keel cutting errors on the tibial side. This technique will be useful for accurate component positioning and therefore improve the longevity of Oxford UKAs. Retrospective comparative study, Level III.

Incidence and risk factors for surgical site infection after open reduction and internal fixation of tibial plateau fracture: A systematic review and meta-analysis.

PubMed

Shao, Jiashen; Chang, Hengrui; Zhu, Yanbin; Chen, Wei; Zheng, Zhanle; Zhang, Huixin; Zhang, Yingze

2017-05-01

This study aimed to quantitatively summarize the risk factors associated with surgical site infection after open reduction and internal fixation of tibial plateau fracture. Medline, Embase, CNKI, Wanfang database and Cochrane central database were searched for relevant original studies from database inception to October 2016. Eligible studies had to meet quality assessment criteria according to the Newcastle-Ottawa Scale, and had to evaluate the risk factors for surgical site infection after open reduction and internal fixation of tibial plateau fracture. Stata 11.0 software was used for this meta-analysis. Eight studies involving 2214 cases of tibial plateau fracture treated by open reduction and internal fixation and 219 cases of surgical site infection were included in this meta-analysis. The following parameters were identified as significant risk factors for surgical site infection after open reduction and internal fixation of tibial plateau fracture (p < 0.05): open fracture (OR 3.78; 95% CI 2.71-5.27), compartment syndrome (OR 3.53; 95% CI 2.13-5.86), operative time (OR 2.15; 95% CI 1.53-3.02), tobacco use (OR 2.13; 95% CI 1.13-3.99), and external fixation (OR 2.07; 95% CI 1.05-4.09). Other factors, including male sex, were not identified as risk factors for surgical site infection. Patients with the abovementioned medical conditions are at risk of surgical site infection after open reduction and internal fixation of tibial plateau fracture. Surgeons should be cognizant of these risks and give relevant preoperative advice. Copyright © 2017. Published by Elsevier Ltd.

Arthroscopic evaluation of soft tissue injuries in tibial plateau fractures: retrospective analysis of 98 cases.

PubMed

Abdel-Hamid, Mohamed Zaki; Chang, Chung-Hsun; Chan, Yi-Sheng; Lo, Yang-Pin; Huang, Jau-Wen; Hsu, Kuo-Yao; Wang, Ching-Jen

2006-06-01

This investigation arthroscopically assesses the frequency of soft tissue injury in tibial plateau fracture according to the severity of fracture patterns. We hypothesized that use of arthroscopy to evaluate soft tissue injury in tibial plateau fractures would reveal a greater number of associated injuries than have previously been reported. From March 1996 to December 2003, 98 patients with closed tibial plateau fractures were treated with arthroscopically assisted reduction and osteosynthesis, with precise diagnosis and management of associated soft tissue injuries. Arthroscopic findings for associated soft tissue injuries were recorded, and the relationship between fracture type and soft tissue injury was then analyzed. The frequency of associated soft tissue injury in this series was 71% (70 of 98). The menisci were injured in 57% of subjects (56 in 98), the anterior cruciate ligament (ACL) in 25% (24 of 98), the posterior cruciate ligament (PCL) in 5% (5 of 98), the lateral collateral ligament (LCL) in 3% (3 of 98), the medial collateral ligament (MCL) in 3% (3 of 98), and the peroneal nerve in 1% (1 of 98); none of the 98 patients exhibited injury to the arteries. No significant association was noted between fracture type and incidence of meniscus, PCL, LCL, MCL, artery, and nerve injury. However, significantly higher injury rates for the ACL were observed in type IV and VI fractures. Soft tissue injury was associated with all types of tibial plateau fracture. Menisci (peripheral tear) and ACL (bony avulsion) were the most commonly injured sites. A variety of soft tissue injuries are common with tibial plateau fracture; these can be diagnosed with the use of an arthroscope. Level III, diagnostic study.

Measurement of bone adjacent to tibial shaft fracture.

PubMed

Findlay, S C; Eastell, R; Ingle, B M

2002-12-01

Delayed union and non-union are common complications after fracture of the tibial shaft. Response of the surrounding bone as a fracture heals could be monitored using techniques currently used in the study of osteoporosis. The aims of our study were to: (1) evaluate the decrement in bone measurements made close to the fracture using dual-energy X-ray absorptiometry (DXA), quantitative ultrasound (QUS) and peripheral quantitative computed tomography (pQCT); (2) compare values for fractured versus non-fractured leg to determine the duration of decrement in bone measurements; and (3) calculate short-term precision in DXA, QUS and pQCT in order to calculate the ratio of decrement to precision (response ratio, RR) to determine the optimal test for monitoring changes after tibial fracture. The biggest decrement in bone measurements at the ipsilateral limb of 28 patients with tibial shaft fracture was observed at the pQCT tibial trabecular sites (distal = 19%, p<0.0001; proximal 5% = 21%, p<0.001; proximal 10% = 28%, p<0.001) and the ultradistal tibia/fibula measured by DXA (19%, p<0.0001). When comparing Z-scores, the magnitude of decrements at the ipsilateral limb was bigger for variables measured directly at the tibia, both proximal and distal to the fracture. The magnitude of the decrement in ultradistal tibia/fibula BMD decreased as the time since fracture increased ( r = 0.55). When response ratios are considered, pQCT measurements at the distal tibia (RR 6-8) and proximal 5% and 10% trabecular sites (RR 5 and 9 respectively) were found to be the most sensitive to change. Therefore, pQCT of the trabecular regions of either the proximal or distal tibia should prove the most sensitive measurement for monitoring changes in bone adjacent to a tibial shaft fracture.

Gait retraining and incidence of medial tibial stress syndrome in army recruits.

PubMed

Sharma, Jagannath; Weston, Matthew; Batterham, Alan M; Spears, Iain R

2014-09-01

Gait retraining, comprising biofeedback and/or an exercise intervention, might reduce the risk of musculoskeletal conditions. The purpose was to examine the effect of a gait-retraining program on medial tibial stress syndrome incidence during a 26-wk basic military training regimen. A total of 450 British Army recruits volunteered. On the basis of a baseline plantar pressure variable (mean foot balance during the first 10% of stance), participants classified as at risk of developing medial tibial stress syndrome (n = 166) were randomly allocated to an intervention (n = 83) or control (n = 83) group. The intervention involved supervised gait retraining, including exercises to increase neuromuscular control and flexibility (three sessions per week) and biofeedback enabling internalization of the foot balance variable (one session per week). Both groups continued with the usual military training regimen. Diagnoses of medial tibial stress syndrome over the 26-wk regimen were made by physicians blinded to the group assignment. Data were modeled in a survival analysis using Cox regression, adjusting for baseline foot balance and time to peak heel rotation. The intervention was associated with a substantially reduced instantaneous relative risk of medial tibial stress syndrome versus control, with an adjusted HR of 0.25 (95% confidence interval, 0.05-0.53). The number needed to treat to observe one additional injury-free recruit in intervention versus control at 20 wk was 14 (11 to 23) participants. Baseline foot balance was a nonspecific predictor of injury, with an HR per 2 SD increment of 5.2 (1.6 to 53.6). The intervention was effective in reducing incidence of medial tibial stress syndrome in an at-risk military sample.

Maintenance percutaneous posterior nerve stimulation for refractory lower urinary tract symptoms in patients with multiple sclerosis: an open label, multicenter, prospective study.

PubMed

Zecca, C; Digesu, G A; Robshaw, P; Singh, A; Elneil, S; Gobbi, C

2014-03-01

Percutaneous tibial nerve stimulation is an effective second line therapy for lower urinary tract symptoms. Data on percutaneous tibial nerve stimulation maintenance treatment are scarce. In this study we evaluate its effectiveness and propose an algorithm of percutaneous tibial nerve stimulation maintenance treatment in patients with multiple sclerosis. In this prospective, multicenter, open label trial consecutive patients with multiple sclerosis and lower urinary tract symptoms unresponsive to medical therapy were treated with 12 weekly sessions of percutaneous tibial nerve stimulation. Responder patients (50% or greater improvement of lower urinary tract symptoms as measured by the patient perception of bladder condition questionnaire) entered a maintenance phase with individualized treatment frequency based on patient response. Lower urinary tract symptoms were assessed using a 3-day frequency volume chart, urodynamics and patient perception of bladder condition questionnaire. Treatment satisfaction was evaluated using a global response assessment scale and a treatment satisfaction visual analog scale. A total of 83 patients were included in the study and 74 (89%) responded to initial treatment. Persistent efficacy occurred in all initial responders after a mean treatment of 24 months. The greatest frequency of maintenance percutaneous tibial nerve stimulation was every 2 weeks. Lower urinary tract symptoms and patient treatment satisfaction improved with time compared to initial treatment (p <0.05). Bladder diary parameters and voiding parameters improved compared to baseline (p <0.05). Prolonged percutaneous tibial nerve stimulation treatment leads to a persistent improvement of lower urinary tract symptoms in patients with multiple sclerosis. Copyright © 2014 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Evaluation of cranial tibial and extensor carpi radialis reflexes before and after anesthetic block in cats.

PubMed

Tudury, Eduardo Alberto; de Figueiredo, Marcella Luiz; Fernandes, Thaiza Helena Tavares; Araújo, Bruno Martins; Bonelli, Marília de Albuquerque; Diogo, Camila Cardoso; Silva, Amanda Camilo; Santos, Cássia Regina Oliveira; Rocha, Nadyne Lorrayne Farias Cardoso

2017-02-01

Objectives This study aimed to test the extensor carpi radialis and cranial tibial reflexes in cats before and after anesthetic block of the brachial and lumbosacral plexus, respectively, to determine whether they depend on a myotatic reflex arc. Methods Fifty-five cats with a normal neurologic examination that were referred for elective gonadectomy were divided into group 1 (29 cats) for testing the extensor carpi radialis reflex, and group 2 (26 cats) for testing the cranial tibial reflex. In group 1, the extensor carpi radialis reflex was tested after anesthetic induction and 15 mins after brachial plexus block with lidocaine. In group 2, the cranial tibial, withdrawal and patellar reflexes were elicited in 52 hindlimbs and retested 15 mins after epidural anesthesia. Results In group 1, before the anesthetic block, 55.17% of the cats had a decreased and 44.83% had a normal extensor carpi radialis reflex. After the block, 68.96% showed a decreased and 27.59% a normal reflex. No cat had an increased or absent reflex before anesthetic block. In group 2, prior to the anesthetic block, 15.38% of the cats had a decreased cranial tibial reflex and 84.62% had a normal response, whereas after the block it was decreased in 26.92% and normal in 73.08% of the cats. None of the cats had an increased or absent reflex. Regarding the presence of both reflexes before and after anesthetic block, there was no significant difference at 1% ( P = 0.013). Conclusions and relevance The extensor carpi radialis and cranial tibial reflexes in cats are not strictly myotatic reflexes, as they are independent of the reflex arc, and may be idiomuscular responses. Therefore, they are not reliable for neurologic examination in this species.

The effect of graft strength on knee laxity and graft in-situ forces after posterior cruciate ligament reconstruction.

PubMed

Lai, Yu-Shu; Chen, Wen-Chuan; Huang, Chang-Hung; Cheng, Cheng-Kung; Chan, Kam-Kong; Chang, Ting-Kuo

2015-01-01

Surgical reconstruction is generally recommended for posterior cruciate ligament (PCL) injuries; however, the use of grafts is still a controversial problem. In this study, a three-dimensional finite element model of the human tibiofemoral joint with articular cartilage layers, menisci, and four main ligaments was constructed to investigate the effects of graft strengths on knee kinematics and in-situ forces of PCL grafts. Nine different graft strengths with stiffness ranging from 0% (PCL rupture) to 200%, in increments of 25%, of an intact PCL's strength were used to simulate the PCL reconstruction. A 100 N posterior tibial drawer load was applied to the knee joint at full extension. Results revealed that the maximum posterior translation of the PCL rupture model (0% stiffness) was 6.77 mm in the medial compartment, which resulted in tibial internal rotation of about 3.01°. After PCL reconstruction with any graft strength, the laxity of the medial tibial compartment was noticeably improved. Tibial translation and rotation were similar to the intact knee after PCL reconstruction with graft strengths ranging from 75% to 125% of an intact PCL. When the graft's strength surpassed 150%, the medial tibia moved forward and external tibial rotation greatly increased. The in-situ forces generated in the PCL grafts ranged from 13.15 N to 75.82 N, depending on the stiffness. In conclusion, the strength of PCL grafts have has a noticeable effect on anterior-posterior translation of the medial tibial compartment and its in-situ force. Similar kinematic response may happen in the models when the PCL graft's strength lies between 75% and 125% of an intact PCL.

Differential induction of c-Fos and phosphorylated ERK by a noxious stimulus after peripheral nerve injury.

PubMed

Tabata, Mitsuyasu; Terayama, Ryuji; Maruhama, Kotaro; Iida, Seiji; Sugimoto, Tomosada

2018-03-01

In this study, we compared induction of c-Fos and phosphorylated extracellular signal-regulated kinase (p-ERK) in the spinal dorsal horn after peripheral nerve injury. We examined the spinal dorsal horn for noxious heat-induced c-Fos and p-ERK protein-like immunoreactive (c-Fos- and p-ERK-IR) neuron profiles after tibial nerve injury. The effect of administration of a MEK 1/2 inhibitor (PD98059) on noxious heat-induced c-Fos expression was also examined after tibial nerve injury. A large number of c-Fos- and p-ERK-IR neuron profiles were induced by noxious heat stimulation to the hindpaw in sham-operated animals. A marked reduction in the number of c-Fos- and p-ERK-IR neuron profiles was observed in the medial 1/3 (tibial territory) of the dorsal horn at 3 and 7 days after nerve injury. Although c-Fos-IR neuron profiles had reappeared by 14 days after injury, the number of p-ERK-IR neuron profiles remained decreased in the tibial territory of the superficial dorsal horn. Double immunofluorescence labeling for c-Fos and p-ERK induced by noxious heat stimulation to the hindpaw at different time points revealed that a large number of c-Fos-IR, but not p-ERK-IR, neuron profiles were distributed in the tibial territory after injury. Although administration of a MEK 1/2 inhibitor to the spinal cord suppressed noxious heat-induced c-Fos expression in the peroneal territory, this treatment did not alter c-Fos induction in the tibial territory after nerve injury. ERK phosphorylation may be involved in c-Fos induction in normal nociceptive responses, but not in exaggerated c-Fos induction after nerve injury.

Racial differences in cortical bone and their relationship to biochemical variables in black and white children in the early stages of puberty

PubMed Central

Warden, Stuart J.; Hill, Kathleen M.; Ferira, Ashley J.; Laing, Emma M.; Martin, Berdine R.; Hausman, Dorothy B.; Weaver, Connie M.; Peacock, Munro; Lewis, Richard D.

2014-01-01

Introduction Racial differences in bone structure likely have roots in childhood as bone size develops predominantly during growth. This study aimed to compare cortical bone health within the tibial diaphysis of black and white children in the early stages of puberty, and explore the contributions of biochemical variables in explaining racial variation in cortical bone properties. Methods A cross-sectional study was performed comparing peripheral quantitative computed tomography-derived cortical bone measures of the tibial diaphysis and biochemical variables in 314 participants (n=155 males; n=164 blacks) in the early stages of puberty. Results Blacks had greater cortical volumetric bone mineral density, mass and size compared to whites (all p<0.01), contributing to blacks having 17.0% greater tibial strength (polar strength-strain index [SSIP]) (p<0.001). Turnover markers indicated blacks had higher bone formation (osteocalcin [OC] and bone specific alkaline phosphatase) and lower bone resorption (N-terminal telopeptide) than whites (all p<0.01). Blacks also had lower 25-hydroxyvitamin D [25(OH)D], and higher 1,25-dihydroxyvitamin D [1,25(OH)2D] and parathyroid hormone (PTH) (all p<0.05). There were no correlations between tibial bone properties, and 25(OH)D and PTH in whites (all p≥0.10); however, SSIP was negatively and positively correlated with 25(OH)D and PTH in blacks, respectively (all p≤0.02). Variation in bone cross-sectional area and SSIP attributable to race was partially explained by tibial length, 25(OH)D/PTH and OC. Conclusions Divergence in tibial cortical bone properties between blacks and whites is established by the early stages of puberty with the enhanced cortical bone properties in black children possibly being explained by higher PTH and OC. PMID:23093348

An Adiabatic Phase-Matching Accelerator

DOE PAGES

Lemery, Francois; Floettmann, Klaus; Piot, Philippe; ...

2018-05-25

We present a general concept to accelerate non-relativistic charged particles. Our concept employs an adiabatically-tapered dielectric-lined waveguide which supports accelerating phase velocities for synchronous acceleration. We propose an ansatz for the transient field equations, show it satisfies Maxwell's equations under an adiabatic approximation and find excellent agreement with a finite-difference time-domain computer simulation. The fields were implemented into the particle-tracking program {\\sc astra} and we present beam dynamics results for an accelerating field with a 1-mm-wavelength and peak electric field of 100~MV/m. The numerical simulations indicate that amore » $$\\sim 200$$-keV electron beam can be accelerated to an energy of $$\\sim10$$~MeV over $$\\sim 10$$~cm. The novel scheme is also found to form electron beams with parameters of interest to a wide range of applications including, e.g., future advanced accelerators, and ultra-fast electron diffraction.« less

Synchronous acceleration with tapered dielectric-lined waveguides

DOE PAGES

Lemery, Francois; Floettmann, Klaus; Piot, Philippe; ...

2018-05-25

Here, we present a general concept to accelerate non-relativistic charged particles. Our concept employs an adiabatically-tapered dielectric-lined waveguide which supports accelerating phase velocities for synchronous acceleration. We propose an ansatz for the transient field equations, show it satisfies Maxwell's equations under an adiabatic approximation and find excellent agreement with a finite-difference time-domain computer simulation. The fields were implemented into the particle-tracking program {\\sc astra} and we present beam dynamics results for an accelerating field with a 1-mm-wavelength and peak electric field of 100~MV/m. The numerical simulations indicate that amore » $$\\sim 200$$-keV electron beam can be accelerated to an energy of $$\\sim10$$~MeV over $$\\sim 10$$~cm. The novel scheme is also found to form electron beams with parameters of interest to a wide range of applications including, e.g., future advanced accelerators, and ultra-fast electron diffraction.« less

An Adiabatic Phase-Matching Accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lemery, Francois; Floettmann, Klaus; Piot, Philippe

2017-12-22

We present a general concept to accelerate non-relativistic charged particles. Our concept employs an adiabatically-tapered dielectric-lined waveguide which supports accelerating phase velocities for synchronous acceleration. We propose an ansatz for the transient field equations, show it satisfies Maxwell's equations under an adiabatic approximation and find excellent agreement with a finite-difference time-domain computer simulation. The fields were implemented into the particle-tracking program {\\sc astra} and we present beam dynamics results for an accelerating field with a 1-mm-wavelength and peak electric field of 100~MV/m. The numerical simulations indicate that amore » $$\\sim 200$$-keV electron beam can be accelerated to an energy of $$\\sim10$$~MeV over $$\\sim 10$$~cm. The novel scheme is also found to form electron beams with parameters of interest to a wide range of applications including, e.g., future advanced accelerators, and ultra-fast electron diffraction.« less

Two Step Acceleration Process of Electrons in the Outer Van Allen Radiation Belt by Time Domain Electric Field Bursts and Large Amplitude Chorus Waves

NASA Astrophysics Data System (ADS)

Agapitov, O. V.; Mozer, F.; Artemyev, A.; Krasnoselskikh, V.; Lejosne, S.

2014-12-01

A huge number of different non-linear structures (double layers, electron holes, non-linear whistlers, etc) have been observed by the electric field experiment on the Van Allen Probes in conjunction with relativistic electron acceleration in the Earth's outer radiation belt. These structures, found as short duration (~0.1 msec) quasi-periodic bursts of electric field in the high time resolution electric field waveform, have been called Time Domain Structures (TDS). They can quite effectively interact with radiation belt electrons. Due to the trapping of electrons into these non-linear structures, they are accelerated up to ~10 keV and their pitch angles are changed, especially for low energies (˜1 keV). Large amplitude electric field perturbations cause non-linear resonant trapping of electrons into the effective potential of the TDS and these electrons are then accelerated in the non-homogeneous magnetic field. These locally accelerated electrons create the "seed population" of several keV electrons that can be accelerated by coherent, large amplitude, upper band whistler waves to MeV energies in this two step acceleration process. All the elements of this chain acceleration mechanism have been observed by the Van Allen Probes.

Experimental Results from a Resonant Dielectric Laser Accelerator

NASA Astrophysics Data System (ADS)

Yoder, Rodney; McNeur, Joshua; Sozer, Esin; Travish, Gil; Hazra, Kiran Shankar; Matthews, Brian; England, Joel; Peralta, Edgar; Wu, Ziran

2015-04-01

Laser-powered accelerators have the potential to operate with very large accelerating gradients (~ GV/m) and represent a path toward extremely compact colliders and accelerator technology. Optical-scale laser-powered devices based on field-shaping structures (known as dielectric laser accelerators, or DLAs) have been described and demonstrated recently. Here we report on the first experimental results from the Micro-Accelerator Platform (MAP), a DLA based on a slab-symmetric resonant optical-scale structure. As a resonant (rather than near-field) device, the MAP is distinct from other DLAs. Its cavity resonance enhances its accelerating field relative to the incoming laser fields, which are coupled efficiently through a diffractive optic on the upper face of the device. The MAP demonstrated modest accelerating gradients in recent experiments, in which it was powered by a Ti:Sapphire laser well below its breakdown limit. More detailed results and some implications for future developments will be discussed. Supported in part by the U.S. Defense Threat Reduction Agency (UCLA); U.S. Dept of Energy (SLAC); and DARPA (SLAC).

Particle Acceleration, Magnetic Field Generation and Emission from Relativistic Jets and Supernova Remnants

NASA Technical Reports Server (NTRS)

Nishikawa, K.-I.; Hartmann, D. H.; Hardee, P.; Hededal, C.; Mizunno, Y.; Fishman, G. J.

2006-01-01

We performed numerical simulations of particle acceleration, magnetic field generation, and emission from shocks in order to understand the observed emission from relativistic jets and supernova remnants. The investigation involves the study of collisionless shocks, where the Weibel instability is responsible for particle acceleration as well as magnetic field generation. A 3-D relativistic particle-in-cell (RPIC) code has been used to investigate the shock processes in electron-positron plasmas. The evolution of theWeibe1 instability and its associated magnetic field generation and particle acceleration are studied with two different jet velocities (0 = 2,5 - slow, fast) corresponding to either outflows in supernova remnants or relativistic jets, such as those found in AGNs and microquasars. Slow jets have intrinsically different structures in both the generated magnetic fields and the accelerated particle spectrum. In particular, the jet head has a very weak magnetic field and the ambient electrons are strongly accelerated and dragged by the jet particles. The simulation results exhibit jitter radiation from inhomogeneous magnetic fields, generated by the Weibel instability, which has different spectral properties than standard synchrotron emission in a homogeneous magnetic field.

ACL reconstruction with hamstring tendon autograft and accelerated brace-free rehabilitation: a systematic review of clinical outcomes

PubMed Central

van Melick, Nicky; van Mourik, Jan B A; Reijman, Max; van Rhijn, Lodewijk W

2018-01-01

Objective To investigate the clinical outcomes after hamstring tendon autograft ACL reconstruction (ACLR) with accelerated, brace-free rehabilitation. Design Systematic review according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Data sources Embase, MEDLINE Ovid, Web of Science, Cochrane CENTRAL and Google scholar from 1 January 1974 to 31 January 2017. Eligibility criteria for selecting studies Study designs reporting outcomes in adults after arthroscopic, primary ACLR with hamstring autograft and accelerated, brace-free rehabilitation. Results Twenty-four studies were included in the review. The clinical outcomes after hamstring tendon autograft ACLR with accelerated brace-free rehabilitation were the following: (1) early start of open kinetic exercises at 4 weeks in a limited range of motion (ROM, 90°−45°) and progressive concentric and eccentric exercises from 12 weeks did not alter outcomes, (2) gender and age did not influence clinical outcomes, (3) anatomical reconstructions showed better results than non-anatomical reconstructions, (4) there was no difference between single-bundle and double-bundle reconstructions, (5) femoral and tibial tunnel widening occurred, (6) hamstring tendons regenerated after harvest and (7) biological knowledge did not support return to sports at 4–6 months. Conclusions After hamstring tendon autograft ACLR with accelerated brace-free rehabilitation, clinical outcome is similar after single-bundle and double-bundle ACLR. Early start of open kinetic exercises at 4 weeks in a limited ROM (90°−45°) and progressive concentric and eccentric exercises from 12 weeks postsurgery do not alter clinical outcome. Further research should focus on achievement of best balance between graft loading and graft healing in the various rehabilitation phases after ACLR as well as on validated, criterion-based assessments for safe return to sports. Level of evidence Level 2b; therapeutic outcome studies. PMID:29682311

Regional fibrocartilage variations in human anterior cruciate ligament tibial insertion: a histological three-dimensional reconstruction.

PubMed

Dai, Can; Guo, Lin; Yang, Liu; Wu, Yi; Gou, Jingyue; Li, Bangchun

2015-02-01

We studied anterior cruciate ligament (ACL) tibial insertion architecture in humans and investigated regional differences that could suggest unequal force transmission from ligament to bone. ACL tibial insertions were processed histologically. With Photoshop software, digital images taken from the histological slides were collaged, contour lines were drawn, and different gray values were filled based on the structure. The data were exported to Amira software for three-dimensional reconstruction. The uncalcified fibrocartilage (UF) layer was divided into three regions: lateral, medial and posterior according to the architecture. The UF zone was significantly thicker laterally than medially or posteriorly (p < 0.05). Similarly, the calcified fibrocartilage (CF) thickness was significantly greater in the lateral part of the enthesis compared to the medial and posterior parts (p < 0.05). The UF quantity (more UF laterally) corresponding to the CF quantity (more CF laterally) at the ACL tibial insertion provides further evidence suggesting that the load transferred from the ACL to the tibia was greater laterally than medially and posteriorly.

Is it possible to re-establish pre-operative patellar kinematics using a ligament-balanced technique in total knee arthroplasty? A cadaveric investigation.

PubMed

Keshmiri, Armin; Springorum, Hans; Baier, Clemens; Zeman, Florian; Grifka, Joachim; Maderbacher, Günther

2015-03-01

Several authors emphasise that the appearance of patellar maltracking after total knee arthroplasty (TKA) is caused by rotational malalignment of the femoral and tibial components. Ligament-balanced femoral component rotation was not found to be associated with abnormal postoperative patellar position. We hypothesised that a ligament-balanced technique in TKA has the ability to best re-establish patellar kinematics. In ten cadaveric knees TKA was performed assessing femoral rotation in ligament-balanced and different femoral and tibial component rotation alignments. Patellar kinematics after different component rotations were analysed using a commercial computer navigation system. Ligament-balanced femoral rotation showed the best re-establishment of patellar kinematics after TKA compared to the healthy pre-operative knee. In contrast to tibial component rotation, femoral component rotation had a major impact on patellofemoral kinematics. This investigation suggests that a ligament-balanced technique in TKA is most likely to re-establish natural patellofemoral kinematics. Tibial component rotation did not influence patellar kinematics.

Study of tibial nerve regeneration in Wistar rats in primary neurorrhaphy with and without gap, wrapped in vein segments.

PubMed

Bastos Dos Santos, Ewerton; Fernandes, Marcela; Gomes Dos Santos, João Baptista; Mattioli Leite, Vilnei; Valente, Sandra Gomes; Faloppa, Flávio

2012-01-01

This study compared nerve regeneration in Wistar rats, using epineural neurorrhaphy with a gap of 1.0 mm and without a gap, both wrapped with jugular vein tubes. Motor neurons in the spinal cord between L3 and S1 were used for the count, marked by exposure of the tibial nerve to Fluoro-Gold (FG). The tibial nerves on both sides were cut and sutured, with a gap on one side and no gap in the other. The sutures were wrapped with a jugular vein. Four months after surgery the tibial nerves were exposed to Fluoro-Gold and the motor neuron count performed in the spinal cord. The results were statistically analyzed by the paired Wilcoxon test. There was a statistical difference between the groups with and without gap in relation to the motor neuron count (p=0.013). The epineural neurorraphy without gap wrapped with jugular vein showed better results for nerve regeneration than the same procedure with gap. Experimental Study .

Balloon osteoplasty--a new technique for reduction and stabilisation of impression fractures in the tibial plateau: a cadaver study and first clinical application.

PubMed

Ahrens, Philipp; Sandmann, Gunther; Bauer, Jan; König, Benjamin; Martetschläger, Frank; Müller, Dirk; Siebenlist, Sebastian; Kirchhoff, Chlodwig; Neumaier, Markus; Biberthaler, Peter; Stöckle, Ulrich; Freude, Thomas

2012-09-01

Fractures of the tibial plateau are among the most severe injuries of the knee joint and lead to advanced gonarthrosis if the reduction does not restore perfect joint congruency. Many different reduction techniques focusing on open surgical procedures have been described in the past. In this context we would like to introduce a novel technique which was first tested in a cadaver setup and has undergone its successful first clinical application. Since kyphoplasty demonstrated effective ways of anatomical correction in spine fractures, we adapted the inflatable instruments and used the balloon technique to reduce depressed fragments of the tibial plateau. The technique enabled us to restore a congruent cartilage surface and bone reduction. In this technique we see a useful new method to reduce depressed fractures of the tibial plateau with the advantages of low collateral damage as it is known from minimally invasive procedures.

Piezoelectric particle accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kemp, Mark A.; Jongewaard, Erik N.; Haase, Andrew A.

2017-08-29

A particle accelerator is provided that includes a piezoelectric accelerator element, where the piezoelectric accelerator element includes a hollow cylindrical shape, and an input transducer, where the input transducer is disposed to provide an input signal to the piezoelectric accelerator element, where the input signal induces a mechanical excitation of the piezoelectric accelerator element, where the mechanical excitation is capable of generating a piezoelectric electric field proximal to an axis of the cylindrical shape, where the piezoelectric accelerator is configured to accelerate a charged particle longitudinally along the axis of the cylindrical shape according to the piezoelectric electric field.

Ultra-high vacuum photoelectron linear accelerator

DOEpatents

Yu, David U.L.; Luo, Yan

2013-07-16

An rf linear accelerator for producing an electron beam. The outer wall of the rf cavity of said linear accelerator being perforated to allow gas inside said rf cavity to flow to a pressure chamber surrounding said rf cavity and having means of ultra high vacuum pumping of the cathode of said rf linear accelerator. Said rf linear accelerator is used to accelerate polarized or unpolarized electrons produced by a photocathode, or to accelerate thermally heated electrons produced by a thermionic cathode, or to accelerate rf heated field emission electrons produced by a field emission cathode.

THREE-DIMENSIONAL NON-VACUUM PULSAR OUTER-GAP MODEL: LOCALIZED ACCELERATION ELECTRIC FIELD IN THE HIGHER ALTITUDES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirotani, Kouichi

2015-01-10

We investigate the particle accelerator that arises in a rotating neutron-star magnetosphere. Simultaneously solving the Poisson equation for the electro-static potential, the Boltzmann equations for relativistic electrons and positrons, and the radiative transfer equation, we demonstrate that the electric field is substantially screened along the magnetic field lines by pairs that are created and separated within the accelerator. As a result, the magnetic-field-aligned electric field is localized in higher altitudes near the light cylinder and efficiently accelerates the positrons created in the lower altitudes outward but does not accelerate the electrons inward. The resulting photon flux becomes predominantly outward, leadingmore » to typical double-peak light curves, which are commonly observed from many high-energy pulsars.« less

A high rate of tibial plateau fractures after early experience with patient-specific instrumentation for unicompartmental knee arthroplasties.

PubMed

Leenders, A M; Schotanus, M G M; Wind, R J P; Borghans, R A P; Kort, N P

2018-04-30

Patient-specific instrumentation (PSI) for unicompartmental knee arthroplasty (UKA) has been available for a few years. However, limited literature is available on this subject. Hence, the aim of this cohort study is to evaluate the 2 years' results of our first experiences with the use of PSI in UKA. It is hypothesised that there is no advantage in rate of adverse events and in radiological and functional outcomes in comparison to literature on the conventional method. This cohort included 129 knees of 122 patients, operated by one surgeon. Outcome measures were the rate of adverse events (AEs); implant position as determined on radiographs; the accuracy of the default and approved planning of the implant sizes and the patient-reported outcome measures (PROMs) preoperatively, and at 3, 12 and 24 months, postoperatively. A total of 6 (4.9%) AEs were observed in this study, with 4 (3.3%) tibial fractures being the main complication. The mean postoperative biomechanical axis was 176.4° and in the majority of cases, the radiographic criteria, as determined by the manufacturer, were met. The tibial component showed 20 (16.4%) outliers in the sagittal and 3 (2.5%) outliers in the frontal plane. There were no outliers of the femoral component. For the femoral and tibial components, respectively, in 125 (96.9%) and 79 (61.7%) cases, there was an agreement between approved planning and implanted component size. All PROMs improved significantly after surgery. Tibial fracture was the most common AE, probably related to the transition from cemented to uncemented UKA. Perioperative modifications to the surgical technique were made in order to prevent this AE. Improvements should be made to the operation technique of the uncemented tibial plateau to obtain an adequate placement and at the same time reduce the risk for tibial fracture. The PSI technique was a reliable tool for the placement of the femoral component. Functional outcome was in line with literature on the conventional method. It is strongly recommended that the surgeon approves every preoperative plan, in order to optimise the accuracy during the PSI surgery. III.

End-to-side neurorrhaphy with and without perineurium.

PubMed

Viterbo, F; Teixeira, E; Hoshino, K; Padovani, C R

1998-01-01

We compared end-to-side neurorraphy with and without the perineural sheath. Twenty rats were used. The peroneal nerve was sectioned and the distal end was sutured to the lateral face of the tibial nerve. We removed the perineural sheath only on the right side, but not on the left side. The proximal end of the peroneal nerve was curved back approximately at a 100 degrees angle and implanted into the adductor muscle. Six months later, the 14 surviving animals were submitted to electrophysiological tests, sacrificed, and the nerves and muscles were taken for histological exams. On the right side, the muscles that had positive response needed an average of 258.89 mV (+/- 92.31) of electric stimulus and on the left side 298.34 mV (+/- 139.32). The average weight of the tibial cranial muscles of the right side was 0.47 g (0.18) and for the left side 0.45 g (0.15). The distal end of the peroneal nerve showed averages of 310.29 (+/- 191.34) nerve fibers on the right side and 287.71 (+/- 183.60) on the left side. The tibial nerve above the neurorraphy showed averages of 939.46 (+/- 223.51) nerve fibers on the right side and 959.46 (+/- 327.48) on the left side. The tibial nerve below the neurorraphy showed averages of 935.17 (+/- 298.65) nerve fibers on the right side and 755.31 (+/- 323.26) on the left side. The average areas of the right tibial cranial muscles were 0.0162 m2 (+/- 0.008), after 230 magnification, and 0.0152 m2 (0.0064) for the left tibial cranial muscles. The histological features of the tibial cranial muscles, taking normal as 100%, were 78.21 (+/- 20.75) on the right side and 82.14 (+/- 15.89) on the left side. The statistical analysis (Student's t test) did not reveal any difference (p > 0.05) among right and left sides for all variables. The authors concluded that the two neurorraphies (with and without perineurium) did not show any difference regarding morphological and electrophysiological features studied.

The fate of neurotization techniques on reinnervation after denervation of the gastrocnemius muscle: an experimental study.

PubMed

Askar, I; Sabuncuoglu, B T; Yormuk, E; Saray, A

2001-07-01

In nerve injuries, if it is not possible to reinnervate muscle by using neurorrhaphy and nerve grafting technique, reinnervation should be provided by the use of neuroization-directly implanting motor nerve into muscle. A comparative study of three techniques of neurotization is presented in rabbits. In this experimental study, a total of 40 white New Zealand rabbits were used and divided into four groups, each including 10 rabbits. In the first group (control--Group 1), only surgical exposure of the gastrocnemius muscle, main muscle nerve (tibial nerve), and peroneal nerve was done, without any injury to the nerves. In the second group (direct neurotization group--Group 2), the tibial nerve was transected, and the peroneal nerve, which had already been divided into fascicles, was implanted into the lateral head of the gastrocnemius muscle aneural zone. In the third group (dual neurotization group--Group 3), the tibial nerve which had been transected and re-anastomosed, and the peroneal nerve were implanted into the lateral head of the gastrocnemius muscle. In the last experimental group (hyperneurotization group--Group 4), fascicles of the peroneal nerve were implanted into the lateral head of the gastrocnemius, preserving the tibial nerve. Six months later, changes in the histologic pattern and the functional recovery of the gastrocnemius muscle were investigated. It was found that functional recovery was achieved in all neurotization groups. Groups with the tibial nerve transected had less muscular weights than those of groups with the tibial nerve intact. EMG recordings showed that polyphasic and late potentials were frequently seen in groups with the tibial nerve transected. Degeneration and regeneration of myofibrils was observed in such groups as well. New motor end-plates, including vesicles, were formed in a scattered manner in all neurotization groups. As a result, the authors conclude that direct and dual neurotization techniques are useful in peripheral nerve injuries, if it is not possible to reinnervate muscle by using neurorraphy and nerve grafting, and that there is no suggested superiority among these techniques.

Cranial cruciate ligament injury in the dog: pathophysiology, diagnosis and treatment.

PubMed

Jerram, R M; Walker, A M

2003-08-01

Cranial cruciate ligament (CCL) disease in the dog is a multifactorial complex problem that requires a thorough understanding of the biomechanics of the stifle joint to be understood. Successful treatment of rupture of the CCL should be based on managing underlying anatomical and conformational abnormalities rather than attempting to eliminate the tibial cranial drawer sign. The cranial and caudal cruciate ligaments, the patella ligament and quadriceps mechanism, the medial and lateral collateral ligaments, the medial and lateral menisci and the joint capsule provide stability of the joint and load-sharing. The function of the stifle is also significantly influenced by the musculature of the pelvic limb. An active model of biomechanics of the stifle has been described that incorporates not only the ligamentous structures of the stifle but also the forces created by weight-bearing and the musculature of the pelvic limb. This model recognises a force called cranial tibial thrust, which occurs during weight-bearing, and causes compression of the femoral condyles against the tibial plateau. In middle-aged, large-breed dogs, forces acting on the CCL together with conformation-related mild hyperextension of the stifle and slightly increased tibial plateau slopes are suspected to cause progressive degeneration of the ligament. Palpation of craniolateral stifle laxity has become pathognomonic for CCL rupture; however, chronic periarticular fibrosis, a partial CCL rupture, and a tense patient, may make evaluation of instability of the stifle difficult. Surgical treatment is broadly separated into three groups: intracapsular, extracapsular, and tibial osteotomy techniques. Tibial osteotomy techniques do not serve to provide stability of the stifle but rather alter the geometry of the joint to eliminate cranial tibial thrust such that functional joint stability is achieved during weight-bearing. Visualisation of both menisci is a critical aspect of CCL surgery, irrespective of the technique being performed. Regardless of the surgical technique employed, approximately 85% of dogs show clinical improvement. However, many of these dogs will demonstrate intermittent pain or lameness. Post-operative management is an integral part of the treatment of CCL rupture, and significant benefits in limb function occur when formalised post-operative physiotherapy is performed.

[Influencing factors for trauma-induced tibial infection in underground coal mine].

PubMed

Meng, W Z; Guo, Y J; Liu, Z K; Li, Y F; Wang, G Z

2016-07-20

Objective: To investigate the influencing factors for trauma-induced tibial infection in underground coal mine. Methods: A retrospective analysis was performed for the clinical data of 1 090 patients with tibial fracture complicated by bone infection who were injured in underground coal mine and admitted to our hospital from January 1995 to August 2015, including the type of trauma, injured parts, severity, and treatment outcome. The association between risk factors and infection was analyzed. Results: Among the 1 090 patients, 357 had the clinical manifestations of acute and chronic bone infection, 219 had red and swollen legs with heat pain, and 138 experienced skin necrosis, rupture, and discharge of pus. The incidence rates of tibial infection from 1995 to 2001, from 2002 to 2008, and from 2009 to 2015 were 31%, 26.9%, and 20.2%, respectively. The incidence rate of bone infection in the proximal segment of the tibia was significantly higher than that in the middle and distal segments (42.1% vs 18.9%/27.1%, P <0.01) . As for patients with different types of trauma (Gustilo typing) , the patients with type III fracture had a significantly higher incidence rate of bone infection than those with type I/II infection (52.8% vs 21.8%/24.6%, P <0.01) . The incidence rates of bone infection after bone traction, internal fixation with steel plates, fixation with external fixator, and fixation with intramedullary nail were 20.7%, 43.5%, 21.4%, and 26.1%, respectively, suggesting that internal fixation with steel plates had a significantly higher incidence rate of bone infection than other fixation methods ( P <0.01) . The multivariate logistic regression analysis showed that the position of tibial fracture and type of fracture were independent risk factors for bone infection. Conclusion: There is a high incidence rate of trauma-induced tibial infection in workers in underground coal mine. The position of tibial fracture and type of fracture are independent risk factors for bone infection. Vacuum sealing drainage and Ilizarov technique can achieve a satisfactory therapeutic effect.

Comparison of fixed-bearing and mobile-bearing total knee arthroplasty after high tibial osteotomy.

PubMed

Hernigou, Philippe; Huys, Maxime; Pariat, Jacques; Roubineau, François; Flouzat Lachaniette, Charles Henri; Dubory, Arnaud

2018-02-01

There is no information comparing the results of fixed-bearing total knee replacement and mobile-bearing total knee replacement in the same patients previously treated by high tibial osteotomy. The purpose was therefore to compare fixed-bearing and mobile-bearing total knee replacements in patients treated with previous high tibial osteotomy. We compared the results of 57 patients with osteoarthritis who had received a fixed-bearing prosthesis after high tibial osteotomy with the results of 41 matched patients who had received a rotating platform after high tibial osteotomy. The match was made for length of follow-up period. The mean follow-up was 17 years (range, 15-20 years). The patients were assessed clinically and radiographically. The pre-operative knee scores had no statistically significant differences between the two groups. So was the case with the intra-operative releases, blood loss, thromboembolic complications and infection rates in either group. There was significant improvement in both groups of knees, and no significant difference was observed between the groups (i.e., fixed-bearing and mobile-bearing knees) for the mean Knee Society knee clinical score (95 and 92 points, respectively), or the Knee Society knee functional score (82 and 83 points, respectively) at the latest follow-up. However, the mean post-operative knee motion was higher for the fixed-bearing group (117° versus 110°). In the fixed-bearing group, one knee was revised because of periprosthetic fracture. In the rotating platform mobile-bearing group, one knee was revised because of aseptic loosening of the tibial component. The Kaplan-Meier survivorship for revision at ten years of follow-up was 95.2% for the fixed bearing prosthesis and 91.1% for the rotating platform mobile-bearing prosthesis. Although we did manage to detect significant differences mainly in clinical and radiographic results between the two groups, we found no superiority or inferiority of the mobile-bearing total knee prosthesis over the fixed-bearing total knee prosthesis for patients previously operated by high tibial osteotomy.

Changing Sagittal-Plane Landing Styles to Modulate Impact and Tibiofemoral Force Magnitude and Directions Relative to the Tibia

PubMed Central

Shimokochi, Yohei; Ambegaonkar, Jatin P.; Meyer, Eric G.

2016-01-01

Context: Ground reaction force (GRF) and tibiofemoral force magnitudes and directions have been shown to affect anterior cruciate ligament loading during landing. However, the kinematic and kinetic factors modifying these 2 forces during landing are unknown. Objective: To clarify the intersegmental kinematic and kinetic links underlying the alteration of the GRF and tibiofemoral force vectors secondary to changes in the sagittal-plane body position during single-legged landing. Design: Crossover study. Setting: Laboratory. Patients or Other Participants: Twenty recreationally active participants (age = 23.4 ± 3.6 years, height = 171.0 ± 9.4 cm, mass = 73.3 ± 12.7 kg). Intervention(s): Participants performed single-legged landings using 3 landing styles: self-selected landing (SSL), body leaning forward and landing on the toes (LFL), and body upright with flat-footed landing (URL). Three-dimensional kinetics and kinematics were recorded. Main Outcome Measure(s): Sagittal-plane tibial inclination and knee-flexion angles, GRF magnitude and inclination angles relative to the tibia, and proximal tibial forces at peak tibial axial forces. Results: The URL resulted in less time to peak tibial axial forces, smaller knee-flexion angles, and greater magnitude and a more anteriorly inclined GRF vector relative to the tibia than did the SSL. These changes led to the greatest peak tibial axial and anterior shear forces in the URL among the 3 landing styles. Conversely, the LFL resulted in longer time to peak tibial axial forces, greater knee-flexion angles, and reduced magnitude and a more posteriorly inclined GRF vector relative to the tibia than the SSL. These changes in LFL resulted in the lowest peak tibial axial and largest posterior shear forces among the 3 landing styles. Conclusions: Sagittal-plane intersegmental kinematic and kinetic links strongly affected the magnitude and direction of GRF and tibiofemoral forces during the impact phase of single-legged landing. Therefore, improving sagittal-plane landing mechanics is important in reducing harmful magnitudes and directions of impact forces on the anterior cruciate ligament. PMID:27723362

Field characteristics of an alvarez-type linac structure having chain-like electrode array

DOE Office of Scientific and Technical Information (OSTI.GOV)

Odera, M.; Goto, A.; Hemmi, M.

1985-10-01

A chain-like electrode configuration in an Alvarez-type linac cavity was studied by models. The structure has been devised to get a moderate shunt impedance together with simplicity of operation, in ion velocity region of more than a few percent of that of light by incorporating focusing scheme by high frequency quadrupolar fields into an TM-010 accelerating field of an Alvarez linac. It has a chain-like electrode array instead of drift tubes containing quadrupole lenses for ordinary linacs. The chain-like electrode structure generates along its central axis, high frequency acceleration and focusing fields alternately, separating the acceleration and focusing functions inmore » space. The separation discriminates this structure from spatially uniform acceleration and focusing scheme of the RFQs devised by Kapchinsky and Teplyakov. It gives beam acceleration effects different from those by conventional linacs and reveals possibility of getting a high acceleration efficiency. Resonant frequency spectrum was found relatively simple by measurements on high frequency models. Separation of unwanted modes from the TM-010 acceleration mode is large; a few 10 MHz, at least. Tilt of the acceleration field is not very sensitive to pertubation in gap capacitance for the TM-010 mode.« less

Accelerated ions from pulsed-power-driven fast plasma flow in perpendicular magnetic field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takezaki, Taichi, E-mail: ttakezaki@stn.nagaokaut.ac.jp; Takahashi, Kazumasa; Sasaki, Toru, E-mail: sasakit@vos.nagaokaut.ac.jp

2016-06-15

To understand the interaction between fast plasma flow and perpendicular magnetic field, we have investigated the behavior of a one-dimensional fast plasma flow in a perpendicular magnetic field by a laboratory-scale experiment using a pulsed-power discharge. The velocity of the plasma flow generated by a tapered cone plasma focus device is about 30 km/s, and the magnetic Reynolds number is estimated to be 8.8. After flow through the perpendicular magnetic field, the accelerated ions are measured by an ion collector. To clarify the behavior of the accelerated ions and the electromagnetic fields, numerical simulations based on an electromagnetic hybrid particle-in-cell methodmore » have been carried out. The results show that the behavior of the accelerated ions corresponds qualitatively to the experimental results. Faster ions in the plasma flow are accelerated by the induced electromagnetic fields modulated with the plasma flow.« less

Posttraumatic tibia valga: a case demonstrating asymmetric activity at the proximal growth plate on technetium bone scan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zionts, L.E.; Harcke, H.T.; Brooks, K.M.

1987-07-01

Posttraumatic tibia valga is a well-recognized complication following fracture of the upper tibial metaphysis in young children. We present a case of a child who developed a valgus deformity following fracture of the proximal tibia and fibula in which quantitative bone scintigraphy at 5 months after injury demonstrated increased uptake at the proximal tibial growth plate with proportionally greater uptake on the medial side. This finding suggests that the valgus deformity in this patient was due to a relative increase in vascularity and consequent overgrowth of the medial portion of the proximal tibial physis.

Coexistence of Extraskeletal Mesenchymal Chondrosarcoma and Isolated Hemihyperplasia: A Case Report

PubMed Central

Demirkiran, Nihat Demirhan; Akdeniz, Olcay; Hapa, Onur; Havıtçıoğlu, Hasan

2016-01-01

Introduction: Arthroscopic fixation of tibial spine fracture without damage to the growth plate is very important in patients with open physis. The present article describes a simple and effective technique being used for the first time to treat this condition. Case report: A 16-year-old boy sustained avulsion fractures of tibial spine while playing. He was treated arthroscopically with excellent result. Conclusion: Arthroscopic fixation of tibial spine fracture in patients with open physis with two cannulated screws perpendicular to each other is a very simple technique which provides strong construct, and allows early mobilization without risk of damage to the growth plate. PMID:27703933

Multiple Osteochondral Allograft Transplantation with Concomitant Tibial Tubercle Osteotomy for Multifocal Chondral Disease of the Knee.

PubMed

Cotter, Eric J; Waterman, Brian R; Kelly, Mick P; Wang, Kevin C; Frank, Rachel M; Cole, Brian J

2017-08-01

Symptomatic patellofemoral chondral lesions are a challenging clinical entity, as these defects may result from persistent lateral patellar maltracking or repetitive microtrauma. Anteromedializing tibial tubercle osteotomy has been shown to be an effective strategy for primary and adjunctive treatment of focal or diffuse patellofemoral disease to improve the biomechanical loading environment. Similarly, osteochondral allograft transplantation has proven efficacy in physiologically young, high-demand patients with condylar or patellofemoral lesions, particularly without early arthritic progression. The authors present the surgical management of a young athlete with symptomatic tricompartmental focal chondral defects with fresh osteochondral allograft transplantation and anteromedializing tibial tubercle osteotomy.

Effect of tibial positioning on the diagnosis of posterolateral rotatory instability in the posterior cruciate ligament-deficient knee.

PubMed

Strauss, Eric J; Ishak, Charbel; Inzerillo, Christopher; Walsh, Michael; Yildirim, Gokce; Walker, Peter; Jazrawi, Laith; Rosen, Jeffrey

2007-08-01

To determine whether positioning of the tibia affects the degree of tibial external rotation seen during a dial test in the posterior cruciate ligament (PCL)-posterolateral corner (PLC)-deficient knee. Laboratory investigation. Biomechanics laboratory. An anterior force applied to the tibia in the combined PCL-PLC-deficient knee will yield increased tibial external rotation during a dial test. The degree of tibial external rotation was measured with 5 Nm of external rotation torque applied to the tibia at both 30 degrees and 90 degrees of knee flexion. Before the torque was applied, an anterior force, a posterior force, or neutral (normal, reduced control) force was applied to the tibia. External rotation measurements were repeated after sequential sectioning of the PCL, the posterolateral structures and the fibular collateral ligament (FCL). Baseline testing of the intact specimens demonstrated a mean external rotation of 18.6 degrees with the knee flexed to 30 degrees (range 16.1-21.0 degrees ), and a mean external rotation of 17.3 degrees with the knee flexed to 90 degrees (range 13.8-20.0 degrees ). Sequential sectioning of the PCL, popliteus and popliteofibular ligament, and the FCL led to a significant increase in tibial external rotation compared with the intact knee for all testing scenarios. After sectioning of the popliteus and popliteofibular ligament, the application of an anterior force during testing led to a mean tibial external rotation that was 5 degrees greater than during testing in the neutral position and 7.5 degrees greater than during testing with a posterior force. In the PCL, popliteus/popliteofibular ligament and FCL-deficient knee, external rotation was 9 degrees and 12 degrees greater with the application of an anterior force during testing compared with neutral positioning and the application of a posterior force, respectively. An anterior force applied to the tibia during the dial test in a combined PCL-PLC-injured knee increased the overall amount of observed tibial external rotation during the dial test. The anterior force reduced the posterior tibial subluxation associated with PCL injury, which is analogous to what is observed when the dial test is performed with the patient in the prone position. Reducing the tibia with either an anterior force when the patient is supine or performing the dial test with the patient in the prone position increases the ability of an examiner to detect a concomitant PLC injury in the setting of a PCL-deficient knee.

Minimally-invasive plate osteosynthesis in distal tibial fractures: Results and complications.

PubMed

Vidović, Dinko; Matejčić, Aljoša; Ivica, Mihovil; Jurišić, Darko; Elabjer, Esmat; Bakota, Bore

2015-11-01

Distal tibial or pilon fractures are usually the result of combined compressive and shear forces, and may result in instability of the metaphysis, with or without articular depression, and injury to the soft tissue. The complexity of injury, lack of muscle cover and poor vascularity make these fractures difficult to treat. Surgical treatment of distal tibial fractures includes several options: external fixation, IM nailing, ORIF and minimally-invasive plate osteosynthesis (MIPO). Management of distal tibial fractures with MIPO enables preservation of soft tissue and remaining blood supply. This is a report of a series of prospectively studied closed distal tibial and pilon fractures treated with MIPO. A total of 21 patients with closed distal tibial or pilon fractures were enrolled in the study between March 2008 and November 2013 and completed follow-up. Demographic characteristics, mechanism of injury, time required for union, ankle range of motion and complications were recorded. Fractures were classified according to the AO/OTA classification. Nineteen patients were initially managed with an ankle-spanning external fixator. When the status of the soft tissue had improved and swelling had subsided enough, a definitive internal fixation with MIPO was performed. Patients were invited for follow-up examinations at 3 and 6 weeks and then at intervals of 6 to 8 weeks until 12 months. Mean age of the patients was 40.1 years (range 19-67 years). Eighteen cases were the result of high-energy trauma and three were the result of low-energy trauma. According to the AO/OTA classification there were extraarticular and intraarticular fractures, but only simple articular patterns without depression or comminution. The average time for fracture union was 19.7 weeks (range 12-38 weeks). Mean range of motion was 10° of dorsiflexion (range 5-15°) and 28.3° of plantar flexion (range 20-35°). Three cases were metalwork-related complications. Two patients underwent plate removal at 24 weeks because of plate impingement. There was one case of wound breakdown at 11 weeks. One patient had fracture union with tibial recurvatum of approximately 10°, without functional impairment. Two patients had delayed union. MIPO is a reliable method of treatment for distal tibial fractures; it provides a high union rate and good functional outcome with minimal soft tissue complications. Skin impingement remains a common complication with MIPO, but this can be solved by timely plate removal. Copyright © 2015 Elsevier Ltd. All rights reserved.

Risk of total knee arthroplasty after operatively treated tibial plateau fracture: a matched-population-based cohort study.

PubMed

Wasserstein, David; Henry, Patrick; Paterson, J Michael; Kreder, Hans J; Jenkinson, Richard

2014-01-15

The aims of operative treatment of displaced tibial plateau fractures are to stabilize the injured knee to restore optimal function and to minimize the risk of posttraumatic arthritis and the eventual need for total knee arthroplasty. The purpose of our study was to define the rate of subsequent total knee arthroplasty after tibial plateau fractures in a large cohort and to compare that rate with the rate in the general population. All patients sixteen years of age or older who had undergone surgical treatment of a tibial plateau fracture from 1996 to 2009 in the province of Ontario, Canada, were identified from administrative health databases with use of surgeon fee codes. Each member of the tibial plateau fracture cohort was matched to four individuals from the general population according to age, sex, income, and urban/rural residence. The rates of total knee arthroplasty at two, five, and ten years were compared by using time-to-event analysis. A separate Cox proportional hazards model was used to explore the influence of patient, provider, and surgical factors on the time to total knee arthroplasty. We identified 8426 patients (48.5% female; median age, 48.9 years) who had undergone fixation of a tibial plateau fracture and matched them to 33,698 controls. The two, five, and ten-year rates of total knee arthroplasty in the plateau fracture and control cohorts were 0.32% versus 0.29%, 5.3% versus 0.82%, and 7.3% versus 1.8%, respectively (p < 0.0001). After adjustment for comorbidity, plateau fracture surgery was found to significantly increase the likelihood of total knee arthroplasty (hazard ratio [HR], 5.29 [95% confidence interval, 4.58, 6.11]; p < 0.0001). Higher rates of total knee arthroplasty were also associated with increasing age (HR, 1.03 [1.03, 1.04] per year over the age of forty-eight; p < 0.0001), bicondylar fracture (HR, 1.53 [1.26, 1.84]; p < 0.0001), and greater comorbidity (HR, 2.17 [1.70, 2.77]; p < 0.001). Ten years after tibial plateau fracture surgery, 7.3% of the patients had had a total knee arthroplasty. This corresponds to a 5.3 times increase in likelihood compared with a matched group from the general population. Older patients and those with more severe fractures are also more likely to need total knee arthroplasty after repair of a tibial plateau fracture.

High brightness electron accelerator

DOEpatents

Sheffield, Richard L.; Carlsten, Bruce E.; Young, Lloyd M.

1994-01-01

A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of acclerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electons as the electrons enter the first cavity.

An unusual stress fracture: Bilateral posterior longitudinal stress fracture of tibia.

PubMed

Malkoc, Melih; Korkmaz, Ozgur; Ormeci, Tugrul; Oltulu, Ismail; Isyar, Mehmet; Mahirogulları, Mahir

2014-01-01

Stress fractures (SF) occur when healthy bone is subjected to cyclic loading, which the normal carrying range capacity is exceeded. Usually, stress fractures occur at the metatarsal bones, calcaneus, proximal or distal tibia and tends to be unilateral. This article presents a 58-year-old male patient with bilateral posterior longitudinal tibial stress fractures. A 58 years old male suffering for persistent left calf pain and decreased walking distance for last one month and after imaging studies posterior longitudinal tibial stress fracture was detected on his left tibia. After six months the patient was admitted to our clinic with the same type of complaints in his right leg. All imaging modalities and blood counts were performed and as a result longitudinal posterior tibial stress fractures were detected on his right tibia. Treatment of tibial stress fracture includes rest and modified activity, followed by a graded return to activity commensurate with bony healing. We have applied the same treatment protocol and our results were acceptable but our follow up time short for this reason our study is restricted for separate stress fractures of the posterior tibia. Although the main localization of tibial stress fractures were unilateral, anterior and transverse pattern, rarely, like in our case, the unusual bilateral posterior localization and longitudinal pattern can be seen. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Newly designed anterolateral and posterolateral locking anatomic plates for lateral tibial plateau fractures: a finite element study.

PubMed

Chen, Pengbo; Lu, Hua; Shen, Hao; Wang, Wei; Ni, Binbin; Chen, Jishizhan

2017-02-23

Lateral column tibial plateau fracture fixation with a locking screw plate has higher mechanical stability than other fixation methods. The objectives of the present study were to introduce two newly designed locking anatomic plates for lateral tibial plateau fracture and to demonstrate their characteristics of the fixation complexes under the axial loads. Three different 3D finite element models of the lateral tibial plateau fracture with the bone plates were created. Various axial forces (100, 500, 1000, and 1500 N) were applied to simulate the axial compressive load on an adult knee during daily life. The equivalent maps of displacement and stress were output, and relative displacement was calculated along the fracture lines. The displacement and stresses in the fixation complexes increased with the axial force. The equivalent displacement or stress map of each fixation under different axial forces showed similar distributing characteristics. The motion characteristics of the three models differed, and the max-shear stress of trabecula increased with the axial load. These two novel plates could fix lateral tibial plateau fractures involving anterolateral and posterolateral fragments. Motions after open reduction and stable internal fixation should be advised to decrease the risk of trabecular microfracture. The relative displacement of the posterolateral fragments is different when using anterolateral plate and posterolateral plate, which should be considered in choosing the implants for different posterolateral plateau fractures.

Neurotized lateral gastrocnemius muscle transfer for persistent traumatic peroneal nerve palsy: Surgical technique.

PubMed

Leclère, F M; Badur, N; Mathys, L; Vögelin, E

2015-08-01

Persistent traumatic peroneal nerve palsy, following nerve surgery failure, is usually treated by tendon transfer or more recently by tibial nerve transfer. However, when there is destruction of the tibial anterior muscle, an isolated nerve transfer is not possible. In this article, we present the key steps and surgical tips for the Ninkovic procedure including transposition of the neurotized lateral gastrocnemius muscle with the aim of restoring active voluntary dorsiflexion. The transposition of the lateral head of the gastrocnemius muscle to the tendons of the anterior tibial muscle group, with simultaneous transposition of the intact proximal end of the deep peroneal nerve to the tibial nerve of the gastrocnemius muscle by microsurgical neurorrhaphy is performed in one stage. It includes 10 key steps which are described in this article. Since 1994, three clinical series have highlighted the advantages of this technique. Functional and subjective results are discussed. We review the indications and limitations of the technique. Early clinical results after neurotized lateral gastrocnemius muscle transfer appear excellent; however, they still need to be compared with conventional tendon transfer procedures. Clinical studies are likely to be conducted in this area largely due to the frequency of persistant peroneal nerve palsy and the limitations of functional options in cases of longstanding peripheral nerve palsy, anterior tibial muscle atrophy or destruction. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Role of high tibial osteotomy in chronic injuries of posterior cruciate ligament and posterolateral corner.

PubMed

Savarese, Eugenio; Bisicchia, Salvatore; Romeo, Rocco; Amendola, Annunziato

2011-03-01

High tibial osteotomy (HTO) is a surgical procedure used to change the mechanical weight-bearing axis and alter the loads carried through the knee. Conventional indications for HTO are medial compartment osteoarthritis and varus malalignment of the knee causing pain and dysfunction. Traditionally, knee instability associated with varus thrust has been considered a contraindication. However, today the indications include patients with chronic ligament deficiencies and malalignment, because an HTO procedure can change not only the coronal but also the sagittal plane of the knee. The sagittal plane has generally been ignored in HTO literature, but its modification has a significant impact on biomechanics and joint stability. Indeed, decreased posterior tibial slope causes posterior tibia translation and helps the anterior cruciate ligament (ACL)-deficient knee. Vice versa, increased tibial slope causes anterior tibia translation and helps the posterior cruciate ligament (PCL)-deficient knee. A review of literature shows that soft tissue procedures alone are often unsatisfactory for chronic posterior instability if alignment is not corrected. Since limb alignment is the most important factor to consider in lower limb reconstructive surgery, diagnosis and treatment of limb malalignment should not be ignored in management of chronic ligamentous instabilities. This paper reviews the effects of chronic posterior instability and tibial slope alteration on knee and soft tissues, in addition to planning and surgical technique for chronic posterior and posterolateral instability with HTO.

Long-term complications following tibial plateau levelling osteotomy in small dogs with tibial plateau angles > 30°.

PubMed

Knight, Rebekah; Danielski, Alan

2018-04-21

Tibial plateau levelling osteotomy (TPLO) is commonly performed for surgical management of cranial cruciate ligament (CCL) disease. It has been suggested that small dogs may have steeper tibial plateau angles (TPAs) than large dogs, which has been associated with increased complication rates after TPLO. A retrospective study was performed to assess the rate and nature of long-term complications following TPLO in small dogs with TPAs>30°. Medical records were reviewed for dogs with TPAs>30° treated for CCL rupture by TPLO with a 2.0 mm plate over a five-year period. Radiographs were assessed to determine TPA, postoperative tibial tuberosity width and to identify any complication. Up-to-date medical records were obtained from the referring veterinary surgeon and any complications in the year after surgery were recorded. The effects of different variables on complication rate were assessed using logistic regression analysis. Minor complications were reported in 22.7 per cent of cases. This is similar to or lower than previously reported complication rates for osteotomy techniques in small dogs and dogs with steep TPAs. A smaller postoperative TPA was the only variable significantly associated with an increased complication rate. No major complications were identified. © British Veterinary Association (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Evidence for reduced cancellous bone mass in the spontaneously hypertensive rat

NASA Technical Reports Server (NTRS)

Wang, T. M.; Hsu, J. F.; Jee, W. S.; Matthews, J. L.

1993-01-01

The histomorphometric changes in the proximal tibial metaphysis and epiphyseal growth plate and midtibial shaft of 26-week-old spontaneously hypertensive rats (SHR) compared with those of the corresponding normotensive Wistar-Kyoto (WKY) rats were studied. A decrease in body weight, growth plate thickness, and longitudinal growth rate of the proximal tibial epiphysis, trabecular bone volume, trabecular thickness and number, the number of osteoblasts and osteoprogenitor cells per millimeter square surface of the proximal tibial metaphysis, periosteal and endocortical apposition rate and bone formation rate of the tibial diaphysis were observed in the SHR. Additionally, systolic blood pressure, the number of osteoclasts per millimeter square surface and average number of nuclei per osteoclast of the proximal tibial metaphysis were significantly increased. Thus, osteoclastic activity is dominant over osteoblastic and chondroblastic activity in the SHR that results in a cancellous bone deficit in the skeleton. It will require additional work to ascertain the underlying cause for this condition as several factors in the SHR with a potential for causing this change are present, including elevated parathyroid hormone (PTH), depressed 1,25-(OH)2D3, low calcium absorption, reduced body weight (reduced loading) elevated blood pressure and possibly other direct cell differences in the mutant strain. At present elevated PTH and adaptation to underloading from reduced weight are postulated to be a likely cause, but additional studies are required to test this interpretation.

Case-related factors affecting cutting errors of the proximal tibia in total knee arthroplasty assessed by computer navigation.

PubMed

Tsukeoka, Tadashi; Tsuneizumi, Yoshikazu; Yoshino, Kensuke; Suzuki, Mashiko

2018-05-01

The aim of this study was to determine factors that contribute to bone cutting errors of conventional instrumentation for tibial resection in total knee arthroplasty (TKA) as assessed by an image-free navigation system. The hypothesis is that preoperative varus alignment is a significant contributory factor to tibial bone cutting errors. This was a prospective study of a consecutive series of 72 TKAs. The amount of the tibial first-cut errors with reference to the planned cutting plane in both coronal and sagittal planes was measured by an image-free computer navigation system. Multiple regression models were developed with the amount of tibial cutting error in the coronal and sagittal planes as dependent variables and sex, age, disease, height, body mass index, preoperative alignment, patellar height (Insall-Salvati ratio) and preoperative flexion angle as independent variables. Multiple regression analysis showed that sex (male gender) (R = 0.25 p = 0.047) and preoperative varus alignment (R = 0.42, p = 0.001) were positively associated with varus tibial cutting errors in the coronal plane. In the sagittal plane, none of the independent variables was significant. When performing TKA in varus deformity, careful confirmation of the bone cutting surface should be performed to avoid varus alignment. The results of this study suggest technical considerations that can help a surgeon achieve more accurate component placement. IV.

Hindfoot Valgus following Interlocking Nail Treatment for Tibial Diaphysis Fractures: Can the Fibula Be Neglected?

PubMed Central

Uzun, Metin; Kara, Adnan; Adaş, Müjdat; Karslioğlu, Bülent; Bülbül, Murat; Beksaç, Burak

2014-01-01

Purpose. We evaluated whether intramedullary nail fixation for tibial diaphysis fractures with concomitant fibula fractures (except at the distal one-third level) managed conservatively with an associated fibula fracture resulted in ankle deformity and assessed the impact of the ankle deformity on lower extremity function. Methods. Sixty middle one-third tibial shaft fractures with associated fibular fractures, except the distal one-third level, were included in this study. All tibial shaft fractures were anatomically reduced and fixed with interlocking intramedullary nails. Fibular fractures were managed conservatively. Hindfoot alignment was assessed clinically. Tibia and fibular lengths were compared to contralateral measurements using radiographs. Functional results were evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Foot and Ankle Disability Index Score (FADI). Results. Anatomic union, defined as equal length in operative and contralateral tibias, was achieved in 60 fractures (100%). Fibular shortening was identified in 42 fractures (68%). Mean fibular shortening was 1.2 cm (range, 0.5–2 cm). Clinical exams showed increased hindfoot valgus in 42 fractures (68%). The mean KOOS was 88.4, and the mean FADI score was 90. Conclusion. Fibular fractures in the middle or proximal one-third may need to be stabilized at the time of tibial intramedullary nail fixation to prevent development of hindfoot valgus due to fibular shortening. PMID:25544899

Management of Open Tibial Shaft Fractures: Does the Timing of Surgery Affect Outcomes?

PubMed

Duyos, Oscar A; Beaton-Comulada, David; Davila-Parrilla, Ariel; Perez-Lopez, Jose Carlos; Ortiz, Krystal; Foy-Parrilla, Christian; Lopez-Gonzalez, Francisco

2017-03-01

Open tibial shaft fractures require emergent care. Treatment with intravenous antibiotics and fracture débridement within 6 to 24 hours is recommended. Few studies have examined outcomes when surgical treatment is performed >24 hours after occurrence of the fracture. This retrospective study included 227 patients aged ≥18 years with isolated open tibial shaft fractures in whom the time to initial débridement was >24 hours. The statistical analysis was based on time from injury to surgical débridement, Gustilo-Anderson classification, method of fixation, union status, and infection status. Fractures débrided within 24 to 48 hours and 48 to 96 hours after injury did not show a statistically significant difference in terms of infection rates (P = 0.984). External fixation showed significantly greater infection rates (P = 0.044) and nonunion rates (P = 0.001) compared with intramedullary nailing. Open tibial shaft fractures should be débrided within 24 hours after injury. Our data indicate that after the 24-hour period and up to 4 days, the risk of infection remains relatively constant independent of the time to débridement. Patients treated with external fixation had more complications than did patients treated with other methods of fixation. Primary reamed intramedullary nailing appears to be a reasonable option for the management of Gustilo-Anderson types 1 and 2 open tibial shaft fractures. Level III retrospective study.

The Effect of Sagittal Plane Deformities after Tibial Plateau Fractures to Functions and Instability of Knee Joint.

PubMed

Erdil, M; Yildiz, F; Kuyucu, E; Sayar, Ş; Polat, G; Ceylan, H H; Koçyiğit, F

2016-01-01

The objective of this study is to evaluate the effect of posterior tibial slope after fracture healing on antero-posterior knee laxity, functional outcome and patient satisfaction. 126 patients who were treated for tibial plateau fractures between 2008-2013 in the orthopedics and traumatology department of our institution were evaluated for the study. Patients were treated with open reduction and internal fixation, arthroscopy assisted minimally invasive osteosynthesis or conservative treatment. Mean posterior tibial slope after the treatment was 6.91 ± 5.11 and there was no significant difference when compared to the uninvolved side 6.42 ± 4,21 (p = 0.794). Knee laxity in anterior-posterior plane was 6.14 ± 2.11 and 5.95 ± 2.25 respectively on healthy and injured side. The difference of mean laxity in anterior-posterior plane between two sides was statistically significant. In this study we found no difference in laxity between the injured and healthy knees. However Tegner score decreased significantly in patients who had greater laxity difference between the knees. We did not find significant difference between fracture type and laxity, IKDC functional scores independent of the ligamentous injury. In conclusion despite coronal alignment is taken into consideration in treatment of tibial plateau fractures, sagittal alignment is reasonably important for stability and should not be ignored.

Fixator-assisted medial tibial plateau elevation to treat severe Blount's disease: outcomes at maturity.

PubMed

Fitoussi, F; Ilharreborde, B; Lefevre, Y; Souchet, P; Presedo, A; Mazda, K; Penneçot, G F

2011-04-01

Severe forms of Blount's disease may be associated with medial tibial plateau (MTP) depression. Management should then take account of joint congruence, laxity, limb axis, torsional abnomality, leg length discrepancy (LLD) and eventual recurrence history. Eight knees (six patients) were managed in a single step comprising MTP elevation osteotomy, lateral epiphysiodesis and proximal tibia osteotomy to correct varus and rotational deformity. Fixation was achieved using an Ilizarov external fixator. Mean age was 10.5 years. Mean hip-knee-ankle (HKA) angle was 151°; distal femoral varus, 94°; metaphyseal-diaphyseal angle (MDA), 27°; and angle of depression of the medial tibial plateau (ADMTP), 42°. Predicted residual proximal tibial growth was 2.6 cm. At a mean 48 months' follow-up, results were good in six cases, medium in one and poor (due to incomplete lateral epiphysiodesis) in one. Mean lateral tibial torsion was 9° and final LLD 11 mm. Weight-bearing was resumed at 2 months, and the fixator was removed at 5.5 months postoperatively. At end of follow-up, mean HKA angle was 179.6°, MDA 7.3° and ADMTP 5.4°. This technically demanding procedure gave satisfactory results in terms of axes and congruence; longer term assessment remains needed. Level IV. Retrospective study. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Distinct hip and rearfoot kinematics in female runners with a history of tibial stress fracture.

PubMed

Milner, Clare E; Hamill, Joseph; Davis, Irene S

2010-02-01

Cross-sectional controlled laboratory study. To investigate the kinematics of the hip, knee, and rearfoot in the frontal and transverse planes in female distance runners with a history of tibial stress fracture. Tibial stress fractures are a common overuse injury in runners, accounting for up to half of all stress fractures. Abnormal kinematics of the lower extremity may contribute to abnormal musculoskeletal load distributions, leading to an increased risk of stress fractures. Thirty female runners with a history of tibial stress fracture were compared to 30 age-matched and weekly-running-distance-matched control subjects with no previous lower extremity bony injuries. Kinematic and kinetic data were collected using a motion capture system and a force platform, respectively, as subjects ran in the laboratory. Selected variables of interest were compared between the groups using a multivariate analysis of variance (MANOVA). Peak hip adduction and peak rearfoot eversion angles were greater in the stress fracture group compared to the control group. Peak knee adduction and knee internal rotation angles and all joint angles at impact peak were similar between the groups. Runners with a previous tibial stress fracture exhibited greater peak hip adduction and rearfoot eversion angles during the stance phase of running compared to healthy controls. A consequence of these mechanics may be altered load distribution within the lower extremity, predisposing individuals to stress fracture.

The developmental morphology of a "periosteal" ligament insertion: growth and maturation of the tibial insertion of the rabbit medial collateral ligament.

PubMed

Matyas, J R; Bodie, D; Andersen, M; Frank, C B

1990-05-01

The structural properties of ligament insertions change dramatically during growth and maturation, but little is known about their developmental anatomy. This study describes and quantifies changes in the gross and microscopic anatomy of the tibial insertion of the rabbit medial collateral ligament (MCL) during development and at skeletal maturity. Eighty animals were used for growth and descriptive studies. From this group, 27 animals, ranging in age from 1 to 24 months, were injected with fluorescent bone markers and their tibial insertions were processed undecalcified for histology. Sections were examined by polarized light and fluorescence microscopy to identify matrix and cells and to quantify mineral formation. Results showed that animals achieved histological skeletal maturity between 9 and 12 months of age. Body weights were a poor index of skeletal maturity. The tibial insertion was composed of five tissue layers, which changed proportions during growth and maturation. In immature animals, MCL fibers entered the periosteum; in older animals, MCL fibers were cemented to the tibia by advancing mineral. The tibial attachment of the MCL was thus transferred from the periosteum to the cortex during growth, suggesting that the term "periosteal insertion" is imprecise in adults. The hypothesis is put forward that these structural changes account for the reported increase in tensile failure of this insertion near skeletal maturity.

Generation of low-emittance electron beams in electrostatic accelerators for FEL applications

NASA Astrophysics Data System (ADS)

Chen, Teng; Elias, Luis R.

1995-02-01

This paper reports results of transverse emittance studies and beam propagation in electrostatic accelerators for free electron laser applications. In particular, we discuss emittance growth analysis of a low current electron beam system consisting of a miniature thermoionic electron gun and a National Electrostatics Accelerator (NEC) tube. The emittance growth phenomenon is discussed in terms of thermal effects in the electron gun cathode and aberrations produced by field gradient changes occurring inside the electron gun and throughout the accelerator tube. A method of reducing aberrations using a magnetic solenoidal field is described. Analysis of electron beam emittance was done with the EGUN code. Beam propagation along the accelerator tube was studied using a cylindrically symmetric beam envelope equation that included beam self-fields and the external accelerator fields which were derived from POISSON simulations.

SMART empirical approaches for predicting field performance of PV modules from results of reliability tests

NASA Astrophysics Data System (ADS)

Hardikar, Kedar Y.; Liu, Bill J. J.; Bheemreddy, Venkata

2016-09-01

Gaining an understanding of degradation mechanisms and their characterization are critical in developing relevant accelerated tests to ensure PV module performance warranty over a typical lifetime of 25 years. As newer technologies are adapted for PV, including new PV cell technologies, new packaging materials, and newer product designs, the availability of field data over extended periods of time for product performance assessment cannot be expected within the typical timeframe for business decisions. In this work, to enable product design decisions and product performance assessment for PV modules utilizing newer technologies, Simulation and Mechanism based Accelerated Reliability Testing (SMART) methodology and empirical approaches to predict field performance from accelerated test results are presented. The method is demonstrated for field life assessment of flexible PV modules based on degradation mechanisms observed in two accelerated tests, namely, Damp Heat and Thermal Cycling. The method is based on design of accelerated testing scheme with the intent to develop relevant acceleration factor models. The acceleration factor model is validated by extensive reliability testing under different conditions going beyond the established certification standards. Once the acceleration factor model is validated for the test matrix a modeling scheme is developed to predict field performance from results of accelerated testing for particular failure modes of interest. Further refinement of the model can continue as more field data becomes available. While the demonstration of the method in this work is for thin film flexible PV modules, the framework and methodology can be adapted to other PV products.

The effect of inertia on the Dirac electron, the spin Hall current and the momentum space Berry curvature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chowdhury, Debashree, E-mail: debashreephys@gmail.com; Basu, B., E-mail: sribbasu@gmail.com

2013-02-15

We have studied the spin dependent force and the associated momentum space Berry curvature in an accelerating system. The results are derived by taking into consideration the non-relativistic limit of a generally covariant Dirac equation with an electromagnetic field present, where the methodology of the Foldy-Wouthuysen transformation is applied to achieve the non-relativistic limit. Spin currents appear due to the combined action of the external electric field, the crystal field and the induced inertial electric field via the total effective spin-orbit interaction. In an accelerating frame, the crucial role of momentum space Berry curvature in the spin dynamics has alsomore » been addressed from the perspective of spin Hall conductivity. For time dependent acceleration, the expression for the spin polarization has been derived. - Highlights: Black-Right-Pointing-Pointer We study the effect of acceleration on the Dirac electron in the presence of an electromagnetic field, where the acceleration induces an electric field. Black-Right-Pointing-Pointer Spin currents appear due to the total effective electric field via the total spin-orbit interaction. Black-Right-Pointing-Pointer We derive the expression for the spin dependent force and the spin Hall current, which is zero for a particular acceleration. Black-Right-Pointing-Pointer The role of the momentum space Berry curvature in an accelerating system is discussed. Black-Right-Pointing-Pointer An expression for the spin polarization for time dependent acceleration is derived.« less

Knee Osteoarthritis Treatment with the KineSpring Knee Implant System: A Report of Two Cases

PubMed Central

Hayes, David A.; Miller, Larry E.; Block, Jon E.

2012-01-01

Osteoarthritis (OA) is a leading cause of disability in middle-aged and older adults with the prevalence expected to increase by 40% by 2025. This dramatic projected increase in OA reflects, in large part, the alarming obesity epidemic. Indeed, it is now well understood that abnormal loading across the knee joint due to malalignment and/or excessive weight gain is responsible for accelerating OA progression. Consequently, there is a therapeutic need for alternative knee OA treatments that directly address joint overload to fill the gap between ineffective conservative care and invasive joint-modifying surgical procedures. We describe two cases that presented with bilateral knee OA resistant to conservative treatments, each with one knee previously and unsuccessfully treated with high tibial osteotomy to improve alignment and the contralateral knee successfully treated with a joint-preserving, load-absorbing implant (KineSpring Knee Implant System). PMID:23304590

Implant Composed of Demineralized Bone and Mesenchymal Stem Cells Genetically Modified with AdBMP2/AdBMP7 for the Regeneration of Bone Fractures in Ovis aries.

PubMed

Hernandez-Hurtado, Adelina A; Borrego-Soto, Gissela; Marino-Martinez, Ivan A; Lara-Arias, Jorge; Romero-Diaz, Viktor J; Abrego-Guerra, Adalberto; Vilchez-Cavazos, Jose F; Elizondo-Riojas, Guillermo; Martinez-Rodriguez, Herminia G; Espinoza-Juarez, Marcela A; Lopez-Romero, Gloria C; Robles-Zamora, Alejandro; Mendoza Lemus, Oscar F; Ortiz-Lopez, Rocio; Rojas-Martinez, Augusto

2016-01-01

Adipose-derived mesenchymal stem cells (ADMSCs) are inducible to an osteogenic phenotype by the bone morphogenetic proteins (BMPs). This facilitates the generation of implants for bone tissue regeneration. This study evaluated the in vitro osteogenic differentiation of ADMSCs transduced individually and in combination with adenoviral vectors expressing BMP2 and BMP7. Moreover, the effectiveness of the implant containing ADMSCs transduced with the adenoviral vectors AdBMP2/AdBMP7 and embedded in demineralized bone matrix (DBM) was tested in a model of tibial fracture in sheep. This graft was compared to ewes implanted with untransduced ADMSCs embedded in the same matrix and with injured but untreated animals. In vivo results showed accelerated osteogenesis in the group treated with the AdBMP2/AdBMP7 transduced ADMSC graft, which also showed improved restoration of the normal bone morphology.

Experimental stimulation of bone healing with teriparatide: histomorphometric and microhardness analysis in a mouse model of closed fracture.

PubMed

Mognetti, Barbara; Marino, Silvia; Barberis, Alessandro; Martin, Anne-Sophie Bravo; Bala, Yohann; Di Carlo, Francesco; Boivin, Georges; Barbos, Michele Portigliatti

2011-08-01

Fracture consolidation is a crucial goal to achieve as early as possible, but pharmacological stimulation has been neglected so far. Teriparatide has been considered for this purpose for its anabolic properties. We set up a murine model of closed tibial fracture on which different doses of teriparatide were tested. Closed fracture treatment avoids any bias introduced by surgical manipulations. Teriparatide's effect on callus formation was monitored during the first 4 weeks from fracture. Callus evolution was determined by histomorphometric and microhardness assessment. Daily administration of 40 μg/kg of teriparatide accelerated callus mineralization from day 9 onward without significant increase of sizes, and at day 15 the microhardness properties of treated callus were similar to those of bone tissue. Teriparatide considerably improved callus consolidation in the very early phases of bone healing.

ELECTRON ACCELERATION AT A CORONAL SHOCK PROPAGATING THROUGH A LARGE-SCALE STREAMER-LIKE MAGNETIC FIELD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kong, Xiangliang; Chen, Yao; Feng, Shiwei

2016-04-10

Using a test-particle simulation, we investigate the effect of large-scale coronal magnetic fields on electron acceleration at an outward-propagating coronal shock with a circular front. The coronal field is approximated by an analytical solution with a streamer-like magnetic field featuring a partially open magnetic field and a current sheet at the equator atop the closed region. We show that the large-scale shock-field configuration, especially the relative curvature of the shock and the magnetic field line across which the shock is sweeping, plays an important role in the efficiency of electron acceleration. At low shock altitudes, when the shock curvature ismore » larger than that of the magnetic field lines, the electrons are mainly accelerated at the shock flanks; at higher altitudes, when the shock curvature is smaller, the electrons are mainly accelerated at the shock nose around the top of closed field lines. The above process reveals the shift of the efficient electron acceleration region along the shock front during its propagation. We also find that, in general, the electron acceleration at the shock flank is not as efficient as that at the top of the closed field because a collapsing magnetic trap can be formed at the top. In addition, we find that the energy spectra of electrons are power-law-like, first hardening then softening with the spectral index varying in a range of −3 to −6. Physical interpretations of the results and implications for the study of solar radio bursts are discussed.« less

Electron acceleration at a coronal shock propagating through a large-scale streamer-like magnetic field

DOE PAGES

Kong, Xiangliang; Chen, Yao; Guo, Fan; ...

2016-04-05

With a test-particle simulation, we investigate the effect of large-scale coronal magnetic fields on electron acceleration at an outward-propagating coronal shock with a circular front. The coronal field is approximated by an analytical solution with a streamer-like magnetic field featured by partially open magnetic field and a current sheet at the equator atop the closed region. We show that the large-scale shock-field configuration, especially the relative curvature of the shock and the magnetic field line across which the shock is sweeping, plays an important role in the efficiency of electron acceleration. At low shock altitudes, when the shock curvature ismore » larger than that of magnetic field lines, the electrons are mainly accelerated at the shock flanks; at higher altitudes, when the shock curvature is smaller, the electrons are mainly accelerated at the shock nose around the top of closed field lines. The above process reveals the shift of efficient electron acceleration region along the shock front during its propagation. We also found that in general the electron acceleration at the shock flank is not so efficient as that at the top of closed field since at the top a collapsing magnetic trap can be formed. In addition, we find that the energy spectra of electrons is power-law like, first hardening then softening with the spectral index varying in a range of -3 to -6. In conclusion, physical interpretations of the results and implications on the study of solar radio bursts are discussed.« less

Participation in Recreational Athletics After Operative Fixation of Tibial Plateau Fractures: Predictors and Functional Outcomes of Those Getting Back in the Game

PubMed Central

Kugelman, David N.; Qatu, Abdullah M.; Haglin, Jack M.; Konda, Sanjit R.; Egol, Kenneth A.

2017-01-01

Background: Tibial plateau fractures can be devastating traumatic injuries to the knee, particularly in active athletes. Purpose/Hypothesis: The purpose of this study was to report on the return to participation in recreational athletics after operatively managed tibial plateau fractures. In addition, this study assessed factors associated with the ability to return to participation in recreational athletics after tibial plateau fractures treated with open reduction internal fixation and compared final outcomes between patients who were able to return to recreational athletics and those who could not. The hypothesis was that returning to participation in recreational athletics would be dependent on the time from surgery after operative fixation of tibial plateau fractures. Less severe injuries would be associated with a quicker return to athletics. Study Design: Case-control study; Level of evidence, 3. Methods: All tibial plateau fractures treated by 1 of 3 surgeons at a single academic institution over an 11-year period were prospectively followed. Final outcomes were evaluated using the Short Musculoskeletal Function Assessment at latest follow-up. All complications were recorded at each follow-up. Differences between the groups were compared using Student t tests for continuous variables. Chi-square analysis was used to determine whether differences between categorical variables existed. Logistic regression was performed to assess independent variables associated with returning to participation in recreational athletics. Results: A total of 169 patients who underwent operative management of their tibial plateau fracture reported participation in recreational athletics before their injury. By the 6-month time point, 48 patients (31.6%) had returned to participation in recreational athletics, and at final follow-up (mean, 15 months), 89 patients (52.4%) had returned to participation in recreational athletics. Predictors of returning to recreational athletics included white race, female sex, social alcohol consumption, younger age, increased range of motion (ROM), low-energy Schatzker patterns (I-III), injuries not inclusive of orthopaedic polytrauma or open fractures, and no postoperative complications. White race, social alcohol consumption, and increased ROM were associated with returning to athletics at both 6-month and final follow-up. Lack of a venous thromboembolism was associated with returning to athletics at final follow-up. Patients who returned to recreational athletics had associations with better functional outcomes and emotional status than those who did not. Conclusion: The number of patients who returned to participation in recreational athletics gradually increased over time after operative fixation of tibial plateau fractures. Less severe injuries and a lack of postoperative complications were associated with a quicker return to athletics. Predictors of returning to participation in recreational athletics after operatively managed tibial plateau fractures can be used to target patients at risk of not returning to play to provide interventions aimed at improving their recovery, such as early knee range of motion, muscle strengthening, and participation in low-impact activities. PMID:29276713

Tibial dyschondroplasia associated proteomic changes in chicken growth plate cartilage

USDA-ARS?s Scientific Manuscript database

Tibial dyschondroplasia (TD) is a poultry leg problem that affects the proximal growth plate of tibia preventing its transition to bone. To understand the disease-induced proteomic changes we compared the protein extracts of cartilage from normal and TD- affected growth plates. TD was induced by fe...

Tibial and Femoral Tunnel Changes After ACL Reconstruction: A Prospective 2-Year Longitudinal MRI Study.

PubMed

Weber, Alexander E; Delos, Demetris; Oltean, Hanna N; Vadasdi, Katherine; Cavanaugh, John; Potter, Hollis G; Rodeo, Scott A

2015-05-01

Tunnel widening after anterior cruciate ligament reconstruction (ACL-R) is a well-accepted and frequent phenomenon, yet little is known regarding its origin or natural history. To prospectively evaluate the cross-sectional area (CSA) changes in tibial and femoral bone tunnels after ACL-R with serial MRI. Case series; Level of evidence, 4. Patients underwent arthroscopic ACL-R with the same surgeon, surgical technique, and rehabilitation protocol. Each patient underwent preoperative dual-energy x-ray absorptiometry and clinical evaluation, as well as postoperative time zero MRI followed by subsequent MRI and clinical examination, including functional and subjective outcome tests, at 6, 12, 24, 52, and 104 weeks. Tibial and femoral tunnel CSA was measured on each MRI at tunnel aperture (ttA and ftA), midsection (ttM and ftM), and exit (ttE and ftE). Logistic regression modeling was used to examine the predictive value of demographic data and preoperative bone quality (as measured by dual-energy x-ray absorptiometry) on functional outcome scores, manual and instrumented laxity measurements, and changes in tunnel area over time. Eighteen patients (including 12 men), mean age 35.5±8.7 years, underwent ACL-R. There was significant tunnel expansion at ttA and ftA sites 6 weeks postoperatively (P=.024 and .0045, respectively). Expansion continued for 24 weeks, with progressive tunnel narrowing thereafter. Average ttA CSA was significantly larger than ftA CSA at all times. The ttM significantly expanded after 6 weeks (P=.06); continued expansion to week 12 was followed by 21 months of reduction in tunnel diameter. The ftM and both ttE and ftE sites decreased in CSA over the 2 years. Median Lysholm and International Knee Documentation Committee scores significantly improved at final follow-up (P=.0083 and <.0001, respectively), and patients returned to preoperative activity levels. Pivot shift significantly decreased (P<.0001). Younger age (<30 years), male sex, and delayed ACL-R (>1 year from time of injury) predicted increased tunnel widening and accelerated expansion in CSA (P<.005). Tunnel expansion after ACL-R occurs early and primarily at the tunnel apertures. Expansion may not affect clinical outcome. Younger age, male sex, and delay from injury to ACL-R may be potential risks for enlargement. © 2015 The Author(s).

Evaluation of the effectiveness of toe board energy-absorbing material for foot, ankle, and lower leg injury reduction.

PubMed

Patalak, John P; Stitzel, Joel D

2018-02-17

Since 2000, numerous improvements have been made to the National Association for Stock Car Auto Racing, Incorporated (NASCAR®) driver restraint system, resulting in improved crash protection for motorsports drivers. Advancements have included seats, head and neck restraints (HNRs), seat belt restraint systems, driver helmets, and others. These enhancements have increased protection for drivers from severe crash loading. Extending protection to the driver's extremities remains challenging. Though the drivers' legs are well contained for lateral and vertical crashes, they remain largely unrestrained in frontal and frontal oblique crashes. Sled testing was conducted for the evaluation of an energy-absorbing (EA) toe board material to be used as a countermeasure for leg and foot injuries. Testing included baseline rigid toe boards, tests with EA material-covered toe boards, and pretest positioning of the 50th percentile male frontal Hybrid III anthropomorphic test device (ATD) lower extremities. ATD leg and foot instrumentation included foot acceleration and tibia forces and moments. The sled test data were evaluated using established injury criteria for tibial plateau fractures, leg shaft fractures, and calcaneus, talus, ankle, and midfoot fractures. A polyurethane EA foam was found to be effective in limiting axial tibia force and foot accelerations when subjected to frontal impacts using the NASCAR motorsport restraint system.

Aligning the magnetic field of a linear induction accelerator with a low-energy electron beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, J.C.; Deadrick, F.J.; Kallman, J.S.

1989-03-10

The Experimental Test Accelerator II (ETA-II) linear induction accelerator at Lawrence Livermore National Laboratory uses a solenoid magnet in each acceleration cell to focus and transport an electron beam over the length of the accelerator. To control growth of the corkscrew mode the magnetic field must be precisely aligned over the full length of the accelerate. Concentric with each solenoid magnet is sine/cosmic-wound correction coil to steer the beam and correct field errors. A low-energy electron probe traces the central flux line through the accelerator referenced to a mechanical axis that is defined by a copropagating laser beam. Correction coilsmore » are activated to force the central flux line to cross the mechanical axis at the end of each acceleration cell. The ratios of correction coil currents determined by the low-energy electron probe are then kept fixed to correct for field errors during normal operation with an accelerated beam. We describe the construction of the low-energy electron probe and report the results of experiments we conducted to measure magnetic alignment with and without the correction coils activated. 5 refs., 3 figs.« less

Effect of Gradual Onset +G(sub z) Acceleration on Rate of Visual Field Collapse and Intraocular Pressure

NASA Technical Reports Server (NTRS)

Haines, Richard F.; Rositano, Salvador A.; Greenleaf, John E.

1976-01-01

The mechanisms that control the size of the visual field during positive acceleration are poorly understood, but involve mainly the arterial blood pressure at the eye level and intraocular pressure (IOP) (3). Fluid and electrolyte shifts that occur in the general circulation during acceleration may well influence the rate at which the visual field collapses. This could, in turn, suggest the relative influences that arterial blood pressure, IOP, and various compensatory mechanisms have upon acceleration tolerance. Such knowledge could also be of use in the design and development of protective techniques for use in the acceleration environment. The present investigation was performed to study blood withdrawal (hypovolemia) and subsequent reinfusion, oral fluid replacement upon IOP, and the rate at which the visual field collapses during gradual onset +G(sub z) acceleration (0.5 G/min).

Particle Acceleration and Radiation associated with Magnetic Field Generation from Relativistic Collisionless Shocks

NASA Technical Reports Server (NTRS)

Nishikawa, K.; Hardee, P. E.; Richardson, G. A.; Preece, R. D.; Sol, H.; Fishman, G. J.

2003-01-01

Shock acceleration is an ubiquitous phenomenon in astrophysical plasmas. Plasma waves and their associated instabilities (e.g., the Buneman instability, two-streaming instability, and the Weibel instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. Using a 3-D relativistic electromagnetic particle (REMP) code, we have investigated particle acceleration associated with a relativistic jet front propagating through an ambient plasma with and without initial magnetic fields. We find only small differences in the results between no ambient and weak ambient magnetic fields. Simulations show that the Weibel instability created in the collisionless shock front accelerates particles perpendicular and parallel to the jet propagation direction. While some Fermi acceleration may occur at the jet front, the majority of electron acceleration takes place behind the jet front and cannot be characterized as Fermi acceleration. The simulation results show that this instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields, which contribute to the electron s transverse deflection behind the jet head. The "jitter" radiation from deflected electrons has different properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

[The speed of nerve-conduction after micro-surgical suture of the tibial nerve of the rabbit (author's transl)].

PubMed

Weigert, M; Mellerowicz, H; Werhahn, C

1975-10-01

Isolated division of the tibial nerve in the thigh preserving the peroneal and sural nerves does not cause loss of normal position of the animal, in particular of sitting. Nor does it lead to pressure sores. The animals are fitter then after division of the sciatic nerve. Microsurgical suture of the isolated tibial nerve in the thigh of the rabbit with 1 or 2 simple sutures with 10 x 0 thread show that an average recovery can be achieved in over 80 per cent. As few sutures as possible should be used. Otherwise there with be scarring and no return of function.

[Magnetic resonance imaging of tibial periostitis].

PubMed

Meyer, X; Boscagli, G; Tavernier, T; Aczel, F; Weber, F; Legros, R; Charlopain, P; Martin, J P

1998-01-01

Tibial periostitis frequently occurs in athletes. We present our experience with MRI in a series of 7 patients (11 legs) with this condition. The clinical presentation and scintigraphic scanning suggested the diagnosis. MRI exploration of 11 legs demonstrated a high band-like juxta-osseous signal enhancement of SE and IR T2 weighted sequences in 6 cases, a signal enhancement after i.v. contrast administration in 4. Tibial periostitis is a clinical diagnosis and MRI and scintigraphic findings can be used to assure the differential diagnosis in difficult cases with stress fracture. MRI can visualize juxta-osseous edematous and inflammatory reactions and an increased signal would appear to be characteristic when the band-like image is fixed to the periosteum.

Concomitant Posterior Hip Dislocation, Ipsilateral Intertrochanteric- and Proximal Tibial- Fractures with Popliteal Artery Injury: A Challenging Trauma Mélange.

PubMed

Chotai, Pranit N; Ebraheim, Nabil A; Hart, Ryan; Wassef, Andrew

2015-11-05

Constellation of ipsilateral posterior hip dislocation, intertrochanteric- and proximal tibial fracture with popliteal artery injury is rare. Management of this presentation is challenging. A motor vehicle accident victim presented with these injuries, but without any initial signs of vascular compromise. Popliteal artery injury was diagnosed intra-operatively and repaired. This was followed by external fixation of tibial fracture, open reduction of dislocated hip and internal fixation of intertrochanteric fracture. Patient regained bilateral complete weight bearing and returned to pre-accident activity level. Apt surgical management including early repair of vascular injury in such a trauma mélange allows for a positive postoperative outcome.

Posterior tibial vein aneurysm presenting as tarsal tunnel syndrome.

PubMed

Ayad, Micheal; Whisenhunt, Anumeha; Hong, EnYaw; Heller, Josh; Salvatore, Dawn; Abai, Babak; DiMuzio, Paul J

2015-06-01

Tarsal tunnel syndrome is a compressive neuropathy of the posterior tibial nerve within the tarsal tunnel. Its etiology varies, including space occupying lesions, trauma, inflammation, anatomic deformity, iatrogenic injury, and idiopathic and systemic causes. Herein, we describe a 46-year-old man who presented with left foot pain. Work up revealed a venous aneurysm impinging on the posterior tibial nerve. Following resection of the aneurysm and lysis of the nerve, his symptoms were alleviated. Review of the literature reveals an association between venous disease and tarsal tunnel syndrome; however, this report represents the first case of venous aneurysm causing symptomatic compression of the nerve. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers

DOEpatents

Danby, G.T.; Jackson, J.W.

1990-03-19

A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations (dB/dt) in the particle beam.

Method of correcting eddy current magnetic fields in particle accelerator vacuum chambers

DOEpatents

Danby, Gordon T.; Jackson, John W.

1991-01-01

A method for correcting magnetic field aberrations produced by eddy currents induced in a particle accelerator vacuum chamber housing is provided wherein correction windings are attached to selected positions on the housing and the windings are energized by transformer action from secondary coils, which coils are inductively coupled to the poles of electro-magnets that are powered to confine the charged particle beam within a desired orbit as the charged particles are accelerated through the vacuum chamber by a particle-driving rf field. The power inductively coupled to the secondary coils varies as a function of variations in the power supplied by the particle-accelerating rf field to a beam of particles accelerated through the vacuum chamber, so the current in the energized correction coils is effective to cancel eddy current flux fields that would otherwise be induced in the vacuum chamber by power variations in the particle beam.

Chromospheric-coronal coupling during solar flares: Current systems and particle acceleration

NASA Technical Reports Server (NTRS)

Winglee, Robert M.; Mckean, M. E.; Dulk, G. A.

1989-01-01

Two-dimensional (three velocity) electrostatic particle simulations are used to investigate the particle heating and acceleration associated with the impulsive phase of a solar flare. A crossfield current in the high corona (which is presumably driven by reconnection processes) is used to initiate the flare. Due to the differential motion of the electrons and ions, currents, and associated quasi-static electric fields are generated with the primary current and balancing return current being on adjacent field lines. These currents extend from the corona down into the chromosphere. Electrons can be accelerated to energies exceeding 100 keV on short time scales via the quasi-static fields and wave-particle interactions. The spectra of these electrons has a broken power-law distribution which hardens in time. The spatially separate primary and return currents are closed by the cross-field acceleration of the ambient ions into the primary current regions. These ions are then accelerated upwards into the corona by the same quasi-static electric field accelerating the electrons downwards. This acceleration can account for the broadened stationary and weak blue shifted component seen in soft x ray line emissions and enhancements in heavy ion abundances seen in the solar wind in associations with solar flares.

Progress with High-Field Superconducting Magnets for High-Energy Colliders

NASA Astrophysics Data System (ADS)

Apollinari, Giorgio; Prestemon, Soren; Zlobin, Alexander V.

2015-10-01

One of the possible next steps for high-energy physics research relies on a high-energy hadron or muon collider. The energy of a circular collider is limited by the strength of bending dipoles, and its maximum luminosity is determined by the strength of final focus quadrupoles. For this reason, the high-energy physics and accelerator communities have shown much interest in higher-field and higher-gradient superconducting accelerator magnets. The maximum field of NbTi magnets used in all present high-energy machines, including the LHC, is limited to ˜10 T at 1.9 K. Fields above 10 T became possible with the use of Nb3Sn superconductors. Nb3Sn accelerator magnets can provide operating fields up to ˜15 T and can significantly increase the coil temperature margin. Accelerator magnets with operating fields above 15 T require high-temperature superconductors. This review discusses the status and main results of Nb3Sn accelerator magnet research and development and work toward 20-T magnets.

Progress with high-field superconducting magnets for high-energy colliders

DOE PAGES

Apollinari, Giorgio; Prestemon, Soren; Zlobin, Alexander V.

2015-10-01

One of the possible next steps for high-energy physics research relies on a high-energy hadron or muon collider. The energy of a circular collider is limited by the strength of bending dipoles, and its maximum luminosity is determined by the strength of final focus quadrupoles. For this reason, the high-energy physics and accelerator communities have shown much interest in higher-field and higher-gradient superconducting accelerator magnets. The maximum field of NbTi magnets used in all present high-energy machines, including the LHC, is limited to ~10 T at 1.9 K. Fields above 10 T became possible with the use of Nbmore » $$_3$$Sn superconductors. Nb$$_3$$Sn accelerator magnets can provide operating fields up to ~15 T and can significantly increase the coil temperature margin. Accelerator magnets with operating fields above 15 T require high-temperature superconductors. Furthermore, this review discusses the status and main results of Nb$$_3$$Sn accelerator magnet research and development and work toward 20-T magnets.« less

Particle acceleration in pulsar magnetospheres

NASA Technical Reports Server (NTRS)

Baker, K. B.

1978-01-01

The structure of pulsar magnetospheres and the acceleration mechanism for charged particles in the magnetosphere was studied using a pulsar model which required large acceleration of the particles near the surface of the star. A theorem was developed which showed that particle acceleration cannot be expected when the angle between the magnetic field lines and the rotation axis is constant (e.g. radial field lines). If this angle is not constant, however, acceleration must occur. The more realistic model of an axisymmetric neutron star with a strong dipole magnetic field aligned with the rotation axis was investigated. In this case, acceleration occurred at large distances from the surface of the star. The magnitude of the current can be determined using the model presented. In the case of nonaxisymmetric systems, the acceleration is expected to occur nearer to the surface of the star.

21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. 888.3590 Section 888.3590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3590...

21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. 888.3590 Section 888.3590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3590...

21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. 888.3590 Section 888.3590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3590...

21 CFR 888.3590 - Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis. 888.3590 Section 888.3590 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3590...

USASOC Injury Prevention/Performance Optimization Musculoskeletal Screening Initiative

DTIC Science & Technology

2012-11-01

gluteus medius) Poor gait pattern/ Overpronation Tibial Stress Fracture Overloading the bone due to excessive running...Excessively tight iliotibial band Hip musculature weakness (e.g. gluteus medius) Poor gait pattern/ Overpronation Tibial Stress Fracture ...Anatomic Location Specific Injuries Probable Causes All lower extremity is at risk for injury during this exercise Foot fractures Improper

Is Remnant Preservation Truly Beneficial to Anterior Cruciate Ligament Reconstruction Healing? Clinical and Magnetic Resonance Imaging Evaluations of Remnant-Preserved Reconstruction.

PubMed

Naraoka, Takuya; Kimura, Yuka; Tsuda, Eiichi; Yamamoto, Yuji; Ishibashi, Yasuyuki

2017-04-01

Remnant-preserved anterior cruciate ligament (ACL) reconstruction was introduced to improve clinical outcomes and biological healing. However, the effects of remnant preservation and the influence of the delay from injury until reconstruction on the outcomes of this technique are still uncertain. Purpose/Hypothesis: The purposes of this study were to evaluate whether remnant preservation improved the clinical outcomes and graft incorporation of ACL reconstruction and to examine the influence of the delay between ACL injury and reconstruction on the usefulness of remnant preservation. We hypothesized that remnant preservation improves clinical results and accelerates graft incorporation and that its effect is dependent on the delay between ACL injury and reconstruction. Cohort study; Level of evidence, 2. A total of 151 consecutive patients who underwent double-bundle ACL reconstruction using a semitendinosus graft were enrolled in this study: 74 knees underwent ACL reconstruction without a remnant (or the remnant was <25% of the intra-articular portion of the graft; NR group), while 77 knees underwent ACL reconstruction with remnant preservation (RP group). These were divided into 4 subgroups based on the time from injury to surgery: phase 1 was <3 weeks (n = 24), phase 2 was 3 to less than 8 weeks (n = 70), phase 3 was 8 to 20 weeks (n = 32), and phase 4 was >20 weeks (n = 25). Clinical measurements, including KT-1000 arthrometer side-to-side anterior tibial translation measurements, were assessed at 3, 6, 12, and 24 months after reconstruction. Magnetic resonance imaging evaluations of graft maturation and graft-tunnel integration of the anteromedial and posterolateral bundles were assessed at 3, 6, and 12 months after reconstruction. There was no difference in side-to-side anterior tibial translation between the NR and RP groups. There was also no difference in graft maturation between the 2 groups. Furthermore, the time from ACL injury until reconstruction did not affect graft maturation, except in the case of very long delays before reconstruction (phase 4). Graft-tunnel integration was significantly increased in both groups in a time-dependent manner. However, there was no difference between the NR and RP groups. Remnant preservation did not improve knee stability at 2 years after ACL reconstruction. Furthermore, remnant preservation did not accelerate graft incorporation, especially during the acute and subacute injury phases.

Indirect reduction technique using a distraction support in minimally invasive percutaneous plate osteosynthesis of tibial shaft fractures.

PubMed

Dong, Wen-Wei; Shi, Zeng-Yuan; Liu, Zheng-Xin; Mao, Hai-Jiao

2016-12-01

To describe an indirect reduction technique during minimally invasive percutaneous plate osteosynthesis (MIPPO) of tibial shaft fractures with the use of a distraction support. Between March 2011 and October 2014, 52 patients with a mean age of 48 years (16-72 years) sustaining tibial shaft fractures were included. All the patients underwent MIPPO for the fractures using a distraction support prior to insertion of the plate. Fracture angular deformity was assessed by goni- ometer measurement on preoperative and postoperative images. Preoperative radiographs revealed a mean of 7.6°(1.2°-28°) angulation in coronal plane and a mean of 6.8°(0.5°-19°) angulation in sagittal plane. Postoperative anteroposterior and lateral radio- graphs showed a mean of 0.8°(0°-4.0°) and 0.6°(0°-3.6°) of varus/valgus and apex anterior/posterior angulation, respectively. No intraoperative or postoperative complications were noted. This study suggests that the distraction support during MIPPO of tibial shaft fractures is an effective and safe method with no associated complications.

Biomechanical analysis of four different fixations for the posterolateral shearing tibial plateau fracture.

PubMed

Zhang, Wei; Luo, Cong-Feng; Putnis, Sven; Sun, Hui; Zeng, Zhi-Min; Zeng, Bing-Fang

2012-03-01

The posterolateral shearing tibial plateau fracture is uncommon in the literature, however with the increased usage of computer tomography (CT), the incidence of these fractures is no longer as low as previously thought. Few studies have concentrated on this fracture, least of all using a biomechanical model. The purpose of this study was to compare and analyse the biomechanical characteristics of four different types of internal fixation to stabilise the posterolateral shearing tibial plateau fracture. Forty synthetic tibiae (Synbone, right) simulated the posterolateral shearing fracture models and these were randomly assigned into four groups; Group A was fixed with two anterolateral lag screws, Group B with an anteromedial Limited Contact Dynamic Compression Plate (LC-DCP), Group C with a lateral locking plate, and Group D with a posterolateral buttress plate. Vertical displacement of the posterolateral fragment was measured using three different strengths of axial loading force, and finally loaded until fixation failure. It was concluded that the posterolateral buttress plate is biomechanically the strongest fixation method for the posterolateral shearing tibial plateau fracture. Copyright © 2011 Elsevier B.V. All rights reserved.

Spontaneous patella fracture associated with anterior tibial tubercle pseudarthrosis in a revised knee replacement following knee Arthrodesis

PubMed Central

2013-01-01

Background Conversion of a knee arthrodesis to a Total Knee Arthroplasty is an uncommon procedure. Revision Total Knee Arthroplasty in this setting presents the surgeon with a number of challenges including the management of the extensor mechanism and patella. Case presentation We describe a unique case of a 69 years old Caucasian man who underwent a revision Total Knee Arthroplasty using a tibial tubercle osteotomy after a previous conversion of a knee arthrodesis without patella resurfacing. Unfortunately 9 months following surgery a tibial tubercle pseudarthrosis and spontaneous patella fracture occurred. Both were managed with open reduction and internal fixation. At 30 months follow-up the tibial tubercle osteotomy had completely consolidated while the patella fracture was still evident but with no signs of further displacement. The patient was completely satisfied with the outcome and had a painless range of knee flexion between 0-95°. Conclusions We believe that patients undergoing this type of surgery require careful counseling regarding the risk of complications both during and after surgery despite strong evidence supporting improved functional outcomes. PMID:24195600

Minimally invasive treatment of tibial pilon fractures through arthroscopy and external fixator-assisted reduction.

PubMed

Luo, Huasong; Chen, Liaobin; Liu, Kebin; Peng, Songming; Zhang, Jien; Yi, Yang

2016-01-01

The aim of this study was to evaluate the clinical outcome of tibial pilon fractures treated with arthroscopy and assisted reduction with an external fixator. Thirteen patients with tibial pilon fractures underwent assisted reduction for limited lower internal fixation with an external fixator under arthroscopic guidance. The weight-bearing time was decided on the basis of repeat radiography of the tibia 3 months after surgery. Postoperative ankle function was evaluated according to the Mazur scoring system. Healing of fractures was achieved in all cases, with no complications such as severe infection, skin necrosis, or an exposed plate. There were 9 excellent, 2 good, and 2 poor outcomes, scored according to the Mazur system. The acceptance rate was 85%. Arthroscopy and external fixator-assisted reduction for the minimally invasive treatment of tibial pilon fractures not only produced less trauma but also protected the soft tissues and blood supply surrounding the fractures. External fixation could indirectly provide reduction and effective operative space for arthroscopic implantation, especially for AO type B fractures and partial AO type C1 fractures.

Case report: comprehensive management of medial tibial stress syndrome

PubMed Central

Krenner, Bernard John

2002-01-01

Abstract Activity or exercise-induced leg pain is a common complication among competitive and “weekend warrior” athletes. Shin splints is a term that has been used to describe all lower leg pain as a result of activity. There are many different causes of “shin splints,” one of which is medial tibial stress syndrome, and the treating clinician must be aware of potentially serious causes of activity related leg pain. Restoring proper biomechanics to the entire kinetic chain and rehabilitation of the injured area should be the primary aim of treatment to optimize shock absorption. The role inflammation plays in medial tibial stress syndrome is controversial, but in this case, seemed to be a causative factor as symptomatology was dramatically decreased with the addition of proteolytic enzymes. Medial tibial stress syndrome can be quite difficult to treat and keeping athletes away from activities that will slow healing or aggravate the condition can be challenging. “Active” rest is the best way in which to allow proper healing while allowing the athlete to maintain their fitness. PMID:19674573

Hybrid external fixation in the treatment of tibial pilon fractures: A retrospective analysis of 162 fractures.

PubMed

Galante, Vito N; Vicenti, Giovanni; Corina, Gianfranco; Mori, Claudio; Abate, Antonella; Picca, Girolamo; Conserva, Vito; Speciale, Domenico; Scialpi, Lorenzo; Tartaglia, Nicola; Caiaffa, Vincenzo; Moretti, Biagio

2016-10-01

To determine the efficacy of hybrid external fixation in the treatment of tibial pilon fractures. Retrospective, multicentre study. Adult patients with tibial pilon fractures treated with hybrid external fixation. Fracture reduction with ligamentotaxis and fixation with XCaliber hybrid external fixator. Fracture union, complications, functional outcome (Mazur Ankle Score). Union was obtained in 159 fractures at an average of 125days; there were three delayed unions and three non-unions. The most frequent complication was superficial pin-track infections (48), all of which responded to local wound care and antibiotics. There were no deep infections and no DVT. Only one fracture had loss of reduction that required frame revision. The overall functional scores were 91 (excellent) for AO/OTA type A fractures, 89 (good) for type B fractures, and 75 (satisfactory) for type C fractures. Hybrid external fixation is an effective method of stabilising tibial pilon fractures, particularly those with marked comminution. The minimally-invasive technique and stable fixation enable early mobilisation, with good functional results and minimal complications. Level IV Case series. Copyright © 2016 Elsevier Ltd. All rights reserved.

Study of tibial nerve regeneration in Wistar rats in primary neurorrhaphy with and without gap, wrapped in vein segments

PubMed Central

Bastos dos Santos, Ewerton; Fernandes, Marcela; Gomes dos Santos, João Baptista; Mattioli Leite, Vilnei; Valente, Sandra Gomes; Faloppa, Flávio

2012-01-01

Objective This study compared nerve regeneration in Wistar rats, using epineural neurorrhaphy with a gap of 1.0 mm and without a gap, both wrapped with jugular vein tubes. Motor neurons in the spinal cord between L3 and S1 were used for the count, marked by exposure of the tibial nerve to Fluoro-Gold (FG). Method The tibial nerves on both sides were cut and sutured, with a gap on one side and no gap in the other. The sutures were wrapped with a jugular vein. Four months after surgery the tibial nerves were exposed to Fluoro-Gold and the motor neuron count performed in the spinal cord. Results The results were statistically analyzed by the paired Wilcoxon test. There was a statistical difference between the groups with and without gap in relation to the motor neuron count (p=0.013). Conclusion The epineural neurorraphy without gap wrapped with jugular vein showed better results for nerve regeneration than the same procedure with gap. Level of Evidence: Experimental Study. PMID:24453597

A Case of Nonunion Avulsion Fracture of the Anterior Tibial Eminence

PubMed Central

Atsumi, Satoru; Arai, Yuji; Nakagawa, Shuji; Inoue, Hiroaki; Ikoma, Kazuya; Fujiwara, Hiroyoshi; Kubo, Toshikazu

2016-01-01

Avulsion fracture of the anterior tibial eminence is an uncommon injury. If bone union does not occur, knee extension will be limited by impingement of the avulsed fragment and knee instability will be induced by dysfunction of the anterior cruciate ligament (ACL). This report describes a 55-year-old woman who experienced an avulsion fracture of the right anterior tibial eminence during recreational skiing. Sixteen months later, she presented at our hospital with limitation of right knee extension. Plain radiography showed nonunion of the avulsion fracture region, and arthroscopy showed that the avulsed fragment impinged the femoral intercondylar notch during knee extension. The anterior region of the bony fragment was debrided arthroscopically until the knee could be extended completely. There was no subsequent instability, and the patient was able to climb a mountain 6 months after surgery. These findings indicate that arthroscopic debridement of an avulsed fragment for nonunion of an avulsion fracture of the anterior tibial eminence is a minimally invasive and effective treatment for middle-aged and elderly patients with a low level of sports activity. PMID:27119035

Plasma Wake-field Acceleration in the Blow-out Regime

NASA Astrophysics Data System (ADS)

Barov, Nikolai; Rosenzweig, James

1999-11-01

Recent experiments at Argonne National Laboratory, investigating the blow-out regime of the plasma wake-field accelerator, are discussed. These experiments achieved stable underdense (beam denser than the ambient plasma density) beam transport, and measured average acceleration of 25 MV/m, corresponding to peak wave fields of over 60 MVm. A comparison of the results to simulation is given, and the physics of the system is discussed. Potential for improvements in performance and achieved acceleration gradient, as well as accelerated beam quality are examined within the context of the next generation of experiments at the Fermilab Test Facility. The status of these experiments will be given.

Convectively driven decadal zonal accelerations in Earth's fluid core

NASA Astrophysics Data System (ADS)

More, Colin; Dumberry, Mathieu

2018-04-01

Azimuthal accelerations of cylindrical surfaces co-axial with the rotation axis have been inferred to exist in Earth's fluid core on the basis of magnetic field observations and changes in the length-of-day. These accelerations have a typical timescale of decades. However, the physical mechanism causing the accelerations is not well understood. Scaling arguments suggest that the leading order torque averaged over cylindrical surfaces should arise from the Lorentz force. Decadal fluctuations in the magnetic field inside the core, driven by convective flows, could then force decadal changes in the Lorentz torque and generate zonal accelerations. We test this hypothesis by constructing a quasi-geostrophic model of magnetoconvection, with thermally driven flows perturbing a steady, imposed background magnetic field. We show that when the Alfvén number in our model is similar to that in Earth's fluid core, temporal fluctuations in the torque balance are dominated by the Lorentz torque, with the latter generating mean zonal accelerations. Our model reproduces both fast, free Alfvén waves and slow, forced accelerations, with ratios of relative strength and relative timescale similar to those inferred for the Earth's core. The temporal changes in the magnetic field which drive the time-varying Lorentz torque are produced by the underlying convective flows, shearing and advecting the magnetic field on a timescale associated with convective eddies. Our results support the hypothesis that temporal changes in the magnetic field deep inside Earth's fluid core drive the observed decadal zonal accelerations of cylindrical surfaces through the Lorentz torque.

2-year follow-up report on micromotion of a short tibia stem. A prospective, randomized RSA study of 59 patients.

PubMed

Molt, Mats; Toksvig-Larsen, Sören

2015-01-01

A shortened tibial stem could influence the early prosthetic fixation. We therefore compared the short stem to the standard-length stem using radiostereometric analysis (RSA) as primary outcome measure. 60 patients were randomized to receive a cemented Triathlon total knee arthroplasty (TKA) with a tibial tray of either standard or short stem length. The patients were blinded regarding treatment allocation. The micromotion of the tibial component was measured by RSA postoperatively, at 3 months, and after 1 and 2 years; clinical outcome was measured with the American Knee Society score (AKSS) and the knee osteoarthritis and injury outcome score (KOOS). The maximum total point motion (MTPM) for the standard stem was 0.36 (SD 0.16) mm at 3 months, 0.51 (SD 0.27) mm at 1 year, and 0.54 (SD 0.28) mm at 2 years. For the short stem, it was 0.42 (0.24) mm, 0.59 (0.43) mm, and 0.61 (0.39) mm. 4 short-stemmed components and 2 standard-stemmed components had more than 0.2 mm of migration between the first- and second-year follow-up, and were classified as continuously migrating. The short-stemmed cemented tibial prosthesis showed an early prosthetic migratory pattern similar to that of the standard-stemmed cemented Triathlon knee prosthesis. The number of continuously migrating tibial plates in each group is predictive of a lower revision rate than 5% at 10 years.

Popliteal versus tibial retrograde access for subintimal arterial flossing with antegrade-retrograde intervention (SAFARI) technique.

PubMed

Hua, W R; Yi, M Q; Min, T L; Feng, S N; Xuan, L Z; Xing, J

2013-08-01

This study aimed to ascertain differences in benefit and effectiveness of popliteal versus tibial retrograde access in subintimal arterial flossing with the antegrade-retrograde intervention (SAFARI) technique. This was a retrospective study of SAFARI-assisted stenting for long chronic total occlusion (CTO) of TASC C and D superficial femoral lesions. 38 cases had superficial femoral artery lesions (23 TASC C and 15 TASC D). All 38 cases underwent SAFARI-assisted stenting. The ipsilateral popliteal artery was retrogradely punctured in 17 patients. A distal posterior tibial (PT) or dorsalis pedis (DP) artery was retrogradely punctured in 21 patients, and 16 of them were punctured after open surgical exposure. SAFARI technical success was achieved in all cases. There was no significant difference in 1-year primary patency (75% vs. 78.9%, p = .86), secondary patency (81.2% vs. 84.2%, p = .91) and access complications (p = 1.00) between popliteal and tibial retrograde access. There was statistical difference in operation time between popliteal (140.1 ± 28.4 min) and tibial retrograde access with PT/DP punctures after surgical vessel exposure (120.4 ± 23.0 min, p = .04). The SAFARI technique is a safe and feasible option for patients with infrainguinal CTO (TASC II C and D). The PT or DP as the retrograde access after surgical vessel exposure is a good choice when using the SAFARI technique. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Impingement of the Mobile Bearing on the Lateral Wall of the Tibial Tray in Unicompartmental Knee Arthroplasty.

PubMed

Inui, Hiroshi; Taketomi, Shuji; Yamagami, Ryota; Sanada, Takaki; Shirakawa, Nobuyuki; Tanaka, Sakae

2016-07-01

Tilting of the mobile bearing relative to the tibial tray in the flexion position may result from the implantation of femoral components more laterally relative to tibial components during unicompartmental knee arthroplasty (UKA) using the Oxford Knee. The purpose of the present study was to compare femoral component positions after UKA using the phase 3 device and a novel device. We further evaluated the placement of the femoral components with the new device in the flexion position to determine the association with short-term prognosis. The location of femoral and tibial components in the flexion position of 38 knees implanted using the phase 3 device and 49 knees using a novel device was assessed at 1 year postoperatively using radiography of the proximal tibia and distal femur in the flexion position. The femoral component was implanted more laterally using the new device than using the phase 3 device in the flexion position (P = .012), which caused the impingement of the mobile bearing against the lateral wall of the tibial tray. After UKA using the new device, 10% of patients exhibited the tilting phenomenon of the mobile bearing because of the lateral implantation of the femoral implant. To prevent implantation of the femoral component too laterally using the new device during UKA, knee surgeons should set the drill guide more medially such that the center of the drill is aligned with the middle of the medial femoral condyle. Copyright © 2016 Elsevier Inc. All rights reserved.

Contact Kinematics Correlates to Tibial Component Migration Following Single Radius Posterior Stabilized Knee Replacement.

PubMed

Teeter, Matthew G; Perry, Kevin I; Yuan, Xunhua; Howard, James L; Lanting, Brent A

2018-03-01

Contact kinematics between total knee arthroplasty components is thought to affect implant migration; however, the interaction between kinematics and tibial component migration has not been thoroughly examined in a modern implant system. A total of 24 knees from 23 patients undergoing total knee arthroplasty with a single radius, posterior stabilized implant were examined. Patients underwent radiostereometric analysis at 2 and 6 weeks, 3 and 6 months, and 1 and 2 years to measure migration of the tibial component in all planes. At 1 year, patients also had standing radiostereometric analysis examinations acquired in 0°, 20°, 40°, and 60° of flexion, and the location of contact and magnitude of any condylar liftoff was measured for each flexion angle. Regression analysis was performed between kinematic variables and migration at 1 year. The average magnitude of maximum total point motion across all patients was 0.671 ± 0.270 mm at 1 year and 0.608 ± 0.359 mm at 2 years (P = .327). Four implants demonstrated continuous migration of >0.2 mm between the first and second year of implantation. There were correlations between the location of contact and tibial component anterior-posterior tilt, varus-valgus tilt, and anterior-posterior translation. The patients with continuous migration demonstrated atypical kinematics and condylar liftoff in some instances. Kinematics can influence tibial component migration, likely through alterations of force transmission. Abnormal kinematics may play a role in long-term implant loosening. Copyright © 2017 Elsevier Inc. All rights reserved.

The Effect of Risk Factors on the Levels of Chemical Elements in the Tibial Plateau of Patients with Osteoarthritis following Knee Surgery.

PubMed

Lanocha-Arendarczyk, Natalia; Kosik-Bogacka, Danuta Izabela; Prokopowicz, Adam; Kalisinska, Elzbieta; Sokolowski, Sebastian; Karaczun, Maciej; Zietek, Pawel; Podlasińska, Joanna; Pilarczyk, Bogumila; Tomza-Marciniak, Agnieszka; Baranowska-Bosiacka, Irena; Gutowska, Izabela; Safranow, Krzysztof; Chlubek, Dariusz

2015-01-01

The aim of this study was to evaluate the aforementioned chemical elements in tibial plateau samples obtained during knee arthroplasty. The gender-specific analysis of chemical element levels in the bone samples revealed that there were statistically significant differences in the concentration of Pb and Se/Pb ratio. The contents of elements in the tibial plateau in the patients with osteoarthritis (OA) can be arranged in the following descending order: F(-) > K > Zn > Fe > Sr > Pb > Mn > Se > Cd > THg. We observed statistical significant effects of environmental factors including smoking, seafood diet, and geographical distribution on the levels of the elements in tibial bone. Significant positive correlation coefficients were found for the relationships K-Cd, Zn-Sr, Zn-F(-), THg-Pb, Pb-Cd, Se-Se/Pb, Se-Se/Cd, Se/Pb-Se/Cd, Pb-Cd/Ca, Cd-Cd/Ca, and F(-)-F(-)/Ca·1000. Significant negative correlations were found for the relationships THg-Se/Pb, Pb-Se/Pb, Cd-Se/Pb, K-Se/Cd, Pb-Se/Cd, Cd-Se/Cd, THg-Se/THg, Pb-Se/THg, Se-Pb/Cd, Zn-Cd/Ca, and Se/Cd-Cd/Ca. The results reported here may provide a basis for establishing reference values for the tibial plateau in patients with OA who had undergone knee replacement surgery. The concentrations of elements in the bone with OA were determined by age, presence of implants, smoking, fish and seafood diet, and sport activity.

Navigation-based femorotibial rotation pattern correlated with flexion angle after total knee arthroplasty.

PubMed

Ishida, Kazunari; Shibanuma, Nao; Matsumoto, Tomoyuki; Sasaki, Hiroshi; Takayama, Koji; Matsuzaki, Tokio; Tei, Katsumasa; Kuroda, Ryosuke; Kurosaka, Masahiro

2016-01-01

To investigate whether intraoperative kinematics obtained by navigation systems can be divided into several kinematic patterns and to assess the correlation between the intraoperative kinematics with maximum flexion angles before and after total knee arthroplasty (TKA). Fifty-four posterior-stabilised (PS) TKA implanted using an image-free navigation system were evaluated. At registration and after implantation, tibial internal rotation angles at maximum extension, 30°, 45°, 60°, 90°, and maximum flexion were collected. The rotational patterns were divided into four groups and were examined the correlation with maximum flexion before and after operation. Tibial internal rotation from 90° of flexion to maximum flexion at registration was correlated with maximum flexion angles pre- and postoperatively. The four groups showed statistically different kinematic patterns. The group with tibial external rotation up to 90° of flexion, following tibial internal rotation at registration, achieved better flexion angles, compared to those of another groups (126.7° ± 12.0°, p < 0.05). The group with tibial external rotation showed the worst flexion angles (80.0° ± 40.4°, p < 0.05). Furthermore, the group with limited extension showed worse flexion angles (111.6° ± 8.9°, p < 0.05). Navigation-based kinematic patterns found at registration predict postoperative maximum flexion angle in PS TKA. Navigation-based kinematics can be useful information during TKA surgery. Diagnostic studies, development of diagnostic criteria in a consecutive series of patients and a universally applied "gold" standard, Level II.

High altitude hypoxia as a factor that promotes tibial growth plate development in broiler chickens

PubMed Central

Huang, Shucheng; Zhang, Lihong; Rehman, Mujeeb Ur; Iqbal, Muhammad Kashif; Lan, Yanfang; Mehmood, Khalid; Zhang, Hui; Qiu, Gang; Nabi, Fazul; Yao, Wangyuan; Wang, Meng; Li, Jiakui

2017-01-01

Tibial dyschondroplasia (TD) is one of the most common problems in the poultry industry and leads to lameness by affecting the proximal growth plate of the tibia. However, due to the unique environmental and geographical conditions of Tibet, no case of TD has been reported in Tibetan chickens (TBCs). The present study was designed to investigate the effect of high altitude hypoxia on blood parameters and tibial growth plate development in chickens using the complete blood count, morphology, and histological examination. The results of this study showed an undesirable impact on the overall performance, body weight, and mortality of Arbor Acres chickens (AACs) exposed to a high altitude hypoxic environment. However, AACs raised under hypoxic conditions showed an elevated number of red blood cells (RBCs) and an increase in hemoglobin and hematocrit values on day 14 compared to the hypobaric normoxia group. Notably, the morphology and histology analyses showed that the size of tibial growth plates in AACs was enlarged and that the blood vessel density was also higher after exposure to the hypoxic environment for 14 days, while no such change was observed in TBCs. Altogether, our results revealed that the hypoxic environment has a potentially new role in increasing the blood vessel density of proximal tibial growth plates to strengthen and enhance the size of the growth plates, which may provide new insights for the therapeutic manipulation of hypoxia in poultry TD. PMID:28282429

Cool excimer laser-assisted angioplasty (CELA) and tibial balloon angioplasty (TBA) in management of infragenicular arterial occlusion in critical lower limb ischemia (CLI).

PubMed

Sultan, Sherif; Tawfick, Wael; Hynes, Niamh

2013-04-01

We aim to compare cool excimer laser-assisted angioplasty (CELA) versus tibial balloon angioplasty (TBA) in patients with critical limb ischemia (CLI) with tibial artery occlusive disease. The primary end point is sustained clinical improvement (SCI) and amputation-free survival (AFS). The secondary end points are binary restenosis, target extremity revascularization (TER), and cost-effectiveness. From June 2005 to October 2010, 1506 patients were referred with peripheral vascular disease and 572 with CLI. A total of 80 patients underwent 89 endovascular revascularizations (EVRs) for tibial occlusions, 47 using TBA and 42 using CELA. All patients were Rutherford category 4 to 6. Three-year SCI was enhanced with CELA (81%) compared to TBA (63.8%; P = .013). Three-year AFS significantly improved with CELA (95.2%) versus TBA (89.4%; P = .0165). Three-year freedom from TER was significantly improved with CELA (92.9%) versus 78.7% TBA (P = .026). Three-year freedom from MACE was comparable in both the groups (P = .455). Patients with CELA had significantly improved quality time without symptoms of disease or toxicity of treatment (Q-TWiST) at 3 years (10.5 months; P = .048) with incremental cost of €2073.19 per quality-adjusted life year gained. Tibial EVR provides exceptional outcome in CLI. The CELA has superior SCI, AFS, and freedom from TER, with improved Q-TWiST and cost-effectiveness.

Cemented tibial component fixation performs better than cementless fixation: a randomized radiostereometric study comparing porous-coated, hydroxyapatite-coated and cemented tibial components over 5 years.

PubMed

Carlsson, Ake; Björkman, Anders; Besjakov, Jack; Onsten, Ingemar

2005-06-01

The question whether the tibial component of a total knee arthroplasty should be fixed to bone with or without bone cement has not yet been definitely answered. We studied movements between the tibial component and bone by radiostereometry (RSA) in total knee replacement (TKR) for 3 different types of fixation: cemented fixation (C-F), uncemented porous fixation (UC-F) and uncemented porous hydroxyapatite fixation (UCHA-F). 116 patients with osteoarthrosis, who had 146 TKRs, were included in 2 randomized series. The first series included 86 unilateral TKRs stratified into 1 of the 3 types of fixation. The second series included 30 patients who had simultaneous bilateral TKR surgery, and who were stratified into 3 subgroups of pairwise comparisons of the 3 types of fixation. After 5 years 2 knees had been revised, neither of which were due to loosening. 1 UCHA-F knee in the unilateral series showed a large and continuous migration and a poor clinical result, and is a pending failure. The C-F knees rotated and migrated less than UC-F and UCHA-F knees over 5 years. UCHA-F migrated less than UC-F after 1 year. Cementing of the tibial component offers more stable bone-implant contact for 5 years compared to uncemented fixation. When using uncemented components, however, there is evidence that augmenting a porous surface with hydroxyapatite may mean less motion between implant and bone after the initial postoperative year.

Online Studies on Variation in Orthopedic Surgery: Computed Tomography in MPEG4 Versus DICOM Format.

PubMed

Mellema, Jos J; Mallee, Wouter H; Guitton, Thierry G; van Dijk, C Niek; Ring, David; Doornberg, Job N

2017-10-01

The purpose of this study was to compare the observer participation and satisfaction as well as interobserver reliability between two online platforms, Science of Variation Group (SOVG) and Traumaplatform Study Collaborative, for the evaluation of complex tibial plateau fractures using computed tomography in MPEG4 and DICOM format. A total of 143 observers started with the online evaluation of 15 complex tibial plateau fractures via either the SOVG or Traumaplatform Study Collaborative websites using MPEG4 videos or a DICOM viewer, respectively. Observers were asked to indicate the absence or presence of four tibial plateau fracture characteristics and to rate their satisfaction with the evaluation as provided by the respective online platforms. The observer participation rate was significantly higher in the SOVG (MPEG4 video) group compared to that in the Traumaplatform Study Collaborative (DICOM viewer) group (75 and 43%, respectively; P < 0.001). The median observer satisfaction with the online evaluation was seven (range, 0-10) using MPEG4 video compared to six (range, 1-9) using DICOM viewer (P = 0.11). The interobserver reliability for recognition of fracture characteristics in complex tibial plateau fractures was higher for the evaluation using MPEG4 video. In conclusion, observer participation and interobserver reliability for the characterization of tibial plateau fractures was greater with MPEG4 videos than with a standard DICOM viewer, while there was no difference in observer satisfaction. Future reliability studies should account for the method of delivering images.

The indications and donor-site morbidity of tibial cortical strut autografts in the management of defects in long bones.

PubMed

Lauthe, O; Soubeyrand, M; Babinet, A; Dumaine, V; Anract, P; Biau, D J

2018-05-01

Aims The primary aim of this study was to determine the morbidity of a tibial strut autograft and characterize the rate of bony union following its use. Patients and Methods We retrospectively assessed a series of 104 patients from a single centre who were treated with a tibial strut autograft of > 5 cm in length. A total of 30 had a segmental reconstruction with continuity of bone, 27 had a segmental reconstruction without continuity of bone, 29 had an arthrodesis and 18 had a nonunion. Donor-site morbidity was defined as any event that required a modification of the postoperative management. Union was assessed clinically and radiologically at a median of 36 months (IQR, 14 to 74). Results Donor-site morbidity occurred in four patients (4%; 95% confidence interval (CI) 1 to 10). One patient had a stress fracture of the tibia, which healed with a varus deformity, requiring an osteotomy. Two patients required evacuation of a haematoma and one developed anterior compartment syndrome which required fasciotomies. The cumulative probability of union was 90% (95% CI 80 to 96) at five years. The type of reconstruction (p = 0.018), continuity of bone (p = 0.006) and length of tibial graft (p = 0.037) were associated with the time to union. Conclusion The tibial strut autograft has a low risk of morbidity and provides adequate bone stock for treating various defects of long bones. Cite this article: Bone Joint J 2018;100-B:667-74.

Effects of low-intensity pulsed ultrasound on radiographic healing of tibial plateau leveling osteotomies in dogs: a prospective, randomized, double-blinded study.

PubMed

Kieves, Nina R; Canapp, Sherman O; Lotsikas, Peter J; Christopher, Scott A; Leasure, Christopher S; Canapp, Debra; Gavin, Patrick R

2018-05-20

To determine the influence of low-intensity pulsed ultrasound (LIPUS) on radiographic healing and limb function after uncomplicated, stable osteotomies in dogs. In vivo, prospective, randomized, double-blinded, placebo-control study. Fifty client-owned dogs. Fifty client-owned dogs with naturally occurring unilateral cranial cruciate ligament rupture were enrolled prior to tibial plateau leveling osteotomy. Dogs were assigned to an active (LIPUS) treatment group or a placebo control (SHAM) treatment group via block randomization on the basis of age, weight, and affected limb. Dogs in the LIPUS treatment group underwent LIPUS treatments for 20 minutes daily: 1.5-MHZ ultrasound wave pulsed at 1 kHZ with a 20% duty cycle at an intensity of 30 mW/cm 2 for the duration of the study (12 weeks). Radiographic evaluation was performed at 4, 8, 10, and 12 weeks postoperatively to evaluate bone healing. Limb function was assessed with temporal-spatial gait analysis preoperatively and at 4, 8, and 12 weeks postoperatively by using a pressure-sensitive walkway system. Both groups had significant improvement in radiographic score and limb use over time. However, there was no significant difference in radiographic bone healing, or limb use as measured by objective gait analysis detected between the LIPUS treatment group and SHAM treatment group at any point in the study. LIPUS treatment did not improve healing in this stable osteotomy model. This study does not provide evidence to support the clinical application of LIPUS to stimulate the healing of stable, uncomplicated osteotomies to accelerate bone healing. © 2018 The American College of Veterinary Surgeons.

Hand-arm vibration in orthopaedic surgery: a neglected risk.

PubMed

Mahmood, F; Ferguson, K B; Clarke, J; Hill, K; Macdonald, E B; Macdonald, D J M

2017-12-30

Hand-arm vibration syndrome is an occupational disease caused by exposure to hand-arm transmitted vibration. The Health and Safety Executive has set limits for vibration exposure, including an exposure action value (EAV), where steps should be taken to reduce exposure, and an exposure limit value (ELV), beyond which vibrating equipment must not be used for the rest of the working day. To measure hand-arm transmitted vibration among orthopaedic surgeons, who routinely use hand-operated saws. We undertook a cadaveric study measuring vibration associated with a tibial cut using battery-operated saws. Three surgeons undertook three tibial cuts each on cadaveric tibiae. Measurements were taken using a frequency-weighted root mean square acceleration, with the vibration total value calculated as the root of the sums squared in each of the three axes. A mean (SD) vibration magnitude of 1 (0.2) m/s2 in the X-axis, 10.3 (1.9) m/s2 in the Y-axis and 4.2 (1.3) m/s2 in the Z-axis was observed. The weighted root mean squared magnitude of vibration was 11.3 (1.7) m/s2. These results suggest an EAV of 23 min and ELV of 1 h 33 min using this equipment. Our results demonstrate that use of a battery-operated sagittal saw can transmit levels of hand-arm vibration approaching the EAV or ELV through prolonged use. Further study is necessary to quantify this risk and establish whether surveillance is necessary for orthopaedic surgeons. © The Author 2017. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Pathomorphism of spiral tibial fractures in computed tomography imaging.

PubMed

Guzik, Grzegorz

2011-01-01

Spiral fractures of the tibia are virtually homogeneous with regard to their pathomorphism. The differences that are seen concern the level of fracture of the fibula, and, to a lesser extent, the level of fracture of the tibia, the length of fracture cleft, and limb shortening following the trauma. While conventional radiographs provide sufficient information about the pathomorphism of fractures, computed tomography can be useful in demonstrating the spatial arrangement of bone fragments and topography of soft tissues surrounding the fracture site. Multiple cross-sectional computed tomography views of spiral fractures of the tibia show the details of the alignment of bone chips at the fracture site, axis of the tibial fracture cleft, and topography of soft tissues that are not visible on standard radiographs. A model of a spiral tibial fracture reveals periosteal stretching with increasing spiral and longitudinal displacement. The cleft in tibial fractures has a spiral shape and its line is invariable. Every spiral fracture of both crural bones results in extensive damage to the periosteum and may damage bellies of the long flexor muscle of toes, flexor hallucis longus as well as the posterior tibial muscle. Computed tomography images of spiral fractures of the tibia show details of damage that are otherwise invisible on standard radiographs. Moreover, CT images provide useful information about the spatial location of the bone chips as well as possible threats to soft tissues that surround the fracture site. Every spiral fracture of the tibia is associated with disruption of the periosteum. 1. Computed tomography images of spiral fractures of the tibia show details of damage otherwise invisible on standard radiographs, 2. The sharp end of the distal tibial chip can damage the tibialis posterior muscle, long flexor muscles of the toes and the flexor hallucis longus, 3. Every spiral fracture of the tibia is associated with disruption of the periosteum.

Epidemiology of metatarsal stress fractures versus tibial and femoral stress fractures during elite training.

PubMed

Finestone, Aharon; Milgrom, Charles; Wolf, Omer; Petrov, Kaloyan; Evans, Rachel; Moran, Daniel

2011-01-01

The training of elite infantry recruits takes a year or more. Stress fractures are known to be endemic in their basic training and the clinical presentation of tibial, femoral, and metatarsal stress fractures are different. Stress fracture incidence during the subsequent progressively more demanding training is not known. The study hypothesis was that after an adaptation period, the incidence of stress fractures during the course of 1 year of elite infantry training would fall in spite of the increasingly demanding training. Seventy-six male elite infantry recruits were followed for the development of stress fractures during a progressively more difficult training program composed of basic training (1 to 14 weeks), advanced training (14 to 26 weeks), and unit training (26 to 52 weeks). Subjects were reviewed regularly and those with clinical suspicion of stress fracture were assessed using bone scan and X-rays. The incidence of stress fractures was 20% during basic training, 14% during advanced training and 23% during unit training. There was a statistically significant difference in the incidence of tibial and femoral stress fractures versus metatarsal stress fractures before and after the completion of phase II training at week 26 (p=0.0001). Seventy-eight percent of the stress fractures during phases I and II training were either tibial or femoral, while 91% of the stress fractures in phase III training were metatarsal. Prior participation in ball sports (p=0.02) and greater tibial length (p=0.05) were protective factors for stress fracture. The study hypothesis that after a period of soldier adaptation, the incidence of stress fractures would decrease in spite of the increasingly demanding elite infantry training was found to be true for tibial and femoral fractures after 6 months of training but not for metatarsal stress fractures. Further studies are required to understand the mechanism of this difference but physicians and others treating stress fractures should be aware of this pattern.

Rap system of stress stimulation can promote bone union after lower tibial bone fracture: a clinical research.

PubMed

Yao, Jian-fei; Shen, Jia-zuo; Li, Da-kun; Lin, Da-sheng; Li, Lin; Li, Qiang; Qi, Peng; Lian, Ke-jian; Ding, Zhen-qi

2012-01-01

Lower tibial bone fracture may easily cause bone delayed union or nonunion because of lacking of dynamic mechanical load. Research Group would design a new instrument as Rap System of Stress Stimulation (RSSS) to provide dynamic mechanical load which would promote lower tibial bone union postoperatively. This clinical research was conducted from January 2008 to December 2010, 92 patients(male 61/female 31, age 16-70 years, mean 36.3 years) who suffered lower tibial bone closed fracture were given intramedullary nail fixation and randomly averagely separated into experimental group and control group(according to the successively order when patients went for the admission procedure). Then researchers analysed the clinical healing time, full weight bearing time, VAS (Visual Analogue Scales) score and callus growth score of Lane-Sandhu in 3,6,12 months postoperatively. The delayed union and nonunion rates were compared at 6 and 12 months separately. All the 92 patients had been followed up (mean 14 months). Clinical bone healing time in experimental group was 88.78±8.80 days but control group was 107.91±9.03 days. Full weight bearing time in experimental group was 94.07±9.81 days but control group was 113.24±13.37 days respectively (P<0.05). The delayed union rate in 6 months was 4.3% in experimental group but 10.9% in control group(P<0.05). The nonunion rate in 12 months was 6.5% in experimental group but 19.6% in control group(P<0.05). In 3, 6, 12 months postoperatively, VAS score and Lane-Sandhu score in experimental group had more significantly difference than them in control group. RSSS can intermittently provide dynamic mechanical load and stimulate callus formation, promote lower tibial bone union, reduce bone delayed union or nonunion rate. It is an adjuvant therapy for promoting bone union after lower tibial bone fracture.

Bracing can partially limit tibial rotation during stressful activities after anterior crucial ligament reconstruction with a hamstring graft.

PubMed

Giotis, D; Paschos, N K; Zampeli, F; Pappas, E; Mitsionis, G; Georgoulis, A D

2016-09-01

Hamstring graft has substantial differences with BPTB graft regarding initial mechanical strength, healing sequence, and vascularization, which may imply that a different approach during rehabilitation period is required. The purpose of this study was to investigate the influence of knee bracing on tibial rotation in ACL-reconstructed patients with a hamstring autograft during high loading activities. The hypothesis was that there would be a decrease in tibial rotation in the ACL-reconstructed braced knee as compared to the unbraced knee. Twenty male patients having undergone unilateral ACL reconstruction with a semitendinosus/gracilis autograft were assessed. Kinematic data were collected with an eight-camera optoelectronic system during two stressful tasks: (1) descending from a stair and subsequent pivoting; and (2) landing from a platform and subsequent pivoting. In each patient, three different experimental conditions were evaluated: (A) wearing a prophylactic brace (braced condition); (B) wearing a patellofemoral brace (sleeved condition); (C) without brace (unbraced condition). The intact knee without brace served as a control. Tibial rotation was significantly lower in the intact knee compared to all three conditions of the ACL-reconstructed knee (P≤0.01 for both tasks). Presence of a brace or sleeve resulted in lower tibial rotation than in the unbraced condition (p=0.003 for descending/pivot and P=0.0004 for landing/pivot). The braced condition resulted in lower rotation than the sleeved condition for descending/pivoting (P=0.031) while no differences were found for landing/pivoting (P=0.230). Knee bracing limited the excessive tibial rotation during pivoting under high loading activities in ACL-reconstructed knees with a hamstring graft. This partial restoration of normal kinematics may have a potential beneficial effect in patients recovering from ACL reconstruction with a hamstring autograft. Level III, case-control therapeutic study. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Load Sharing Among Collateral Ligaments, Articular Surfaces, and the Tibial Post in Constrained Condylar Knee Arthroplasty.

PubMed

Wang, Xiaonan; Malik, Aamer; Bartel, Donald L; Wright, Timothy M; Padgett, Douglas E

2016-08-01

The normal knee joint maintains stable motion during activities of daily living. After total knee arthroplasty (TKA), stability is achieved by the conformity of the bearing surfaces of the implant components, ligaments, and constraint structures incorporated in the implant design. The large, rectangular tibial post in constrained condylar knee (CCK) arthroplasty, often used in revision surgery, provides added stability, but increases susceptibility to polyethylene wear as it contacts the intercondylar box on the femoral component. We examined coronal plane stability to understand the relative contributions of the mechanisms that act to stabilize the CCK knee under varus-valgus loading, namely, load distribution between the medial and lateral condyles, contact of the tibial post with the femoral intercondylar box, and elongation of the collateral ligaments. A robot testing system was used to determine the joint stability in human cadaveric knees as described by the moment versus angular rotation behavior under varus-valgus moments at 0 deg, 30 deg, and 90 deg of flexion. The angular rotation of the CCK knee in response to the physiological moments was limited to ≤1.5 deg. The primary stabilizing mechanism was the redistribution of the contact force on the bearing surfaces. Contact between the tibial post and the femoral box provided a secondary stabilizing mechanism after lift-off of a condyle had occurred. Collateral ligaments provide limited stability because little ligament elongation occurred under such small angular rotations. Compressive loads applied across the knee joint, such as would occur with the application of muscle forces, enhanced the ability of the bearing surfaces to provide resisting internal varus-valgus moment and, thus, reduced the exposure of the tibial post to the external varus-valgus loads. Our results suggest that the CCK stability can be refined by considering both the geometry of the bearing surfaces and the contacting geometry between the tibial post and femoral box.

The Effect of Arch Drop on Tibial Rotation and Tibiofemoral Contact Stress in Postpartum Women.

PubMed

Rabe, Kaitlin; Segal, Neil A; Waheed, Saphia; Anderson, Donald D

2018-04-26

Women are at greater risk for knee osteoarthritis and numerous other lower limb musculoskeletal disorders. Arch drop during pregnancy and the resultant excessive pronation of the feet may alter loading patterns and contribute to the greater prevalence of knee osteoarthritis in women. To determine the effect of arch drop on tibial rotation and tibiofemoral contact stress. Interventional study with internal control. Biomechanics laboratory. Eleven postpartum women (age 33.4 ± 5.3 years, body mass 76.1 ± 13.5 kg) who had lost arch height with pregnancy in a previous study. Subjects underwent standing computed tomography (SCT) with their knees in a 20° fixed-flexed position with and without semirigid arch supports to reconstitute prepregnancy arch height. Magnetic resonance imaging of the knee was acquired at a flexion angle equivalent to that of SCT. Bone and cartilage were manually segmented on the magnetic resonance images and segmented surfaces were registered to the 3-dimensional SCT image sets for the arch-supported and -unsupported conditions. These models were used to measure changes in tibial rotation, as well as to estimate contact stress in the medial and lateral tibiofemoral compartments, using computational methods. Change in tibial rotation and tibiofemoral contact stress with arch drop. Arch drop resulted in a mean tibial internal rotation of 0.75 ± 1.33° (P < .05). Changes in mean or peak contact stress were not detected. Arch drop causes internal tibial rotation, resulting in a shift in the tibiofemoral articulation. An associated increase in contact stress was not detected. Internal rotation of the tibia increases stress on the anterior cruciate ligament and menisci, potentially explaining the greater prevalence of knee disorders in postpartum women. Copyright © 2018 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Assessment of tibial rotation and meniscal movement using kinematic magnetic resonance imaging

PubMed Central

2014-01-01

Objective This work aimed to assess tibial rotations, meniscal movements, and morphological changes during knee flexion and extension using kinematic magnetic resonance imaging (MRI). Methods Thirty volunteers with healthy knees were examined using kinematic MRI. The knees were imaged in the transverse plane with flexion and extension angles from 0° to 40° and 40° to 0°, respectively. The tibial interior and exterior rotation angles were measured, and the meniscal movement range, height change, and side movements were detected. Results The tibia rotated internally (11.55° ± 3.20°) during knee flexion and rotated externally (11.40° ± 3.0°) during knee extension. No significant differences were observed between the internal and external tibial rotation angles (P > 0.05), between males and females (P > 0.05), or between the left and right knee joints (P > 0.05). The tibial rotation angle with a flexion angle of 0° to 24° differed significantly from that with a flexion angle of 24° to 40° (P < 0.01). With knee flexion, the medial and lateral menisci moved backward and the height of the meniscus increased. The movement range was greater in the anterior horn than in the posterior horn and greater in the lateral meniscus than in the medial meniscus (P < 0.01). During backward movements of the menisci, the distance between the anterior and posterior horns decreased, with the decrease more apparent in the lateral meniscus (P < 0.01). The side movements of the medial and lateral menisci were not obvious, and a smaller movement range was found than that of the forward and backward movements. Conclusion Knee flexion and extension facilitated internal and external tibial rotations, which may be related to the ligament and joint capsule structure and femoral condyle geometry. PMID:25142267

Extreme mobility in the Late Pleistocene? Comparing limb biomechanics among fossil Homo, varsity athletes and Holocene foragers.

PubMed

Shaw, Colin N; Stock, Jay T

2013-04-01

Descriptions of Pleistocene activity patterns often derive from comparisons of long bone diaphyseal robusticity across contemporaneous fossilized hominins. The purpose of this study is to augment existing understanding of Pleistocene hominin mobility patterns by interpreting fossil variation through comparisons with a) living human athletes with known activity patterns, and b) Holocene foragers where descriptions of group-level activity patterns are available. Relative tibial rigidity (midshaft tibial rigidity (J)/midshaft humeral rigidity (J)) was compared amongst Levantine and European Neandertals, Levantine and Upper Palaeolithic Homo sapiens, Holocene foragers and living human athletes and controls. Cross-country runners exhibit significantly (p<0.05) greater relative tibial rigidity compared with swimmers, and higher values compared with controls. In contrast, swimmers displayed significantly (p<0.05) lower relative tibial rigidity than both runners and controls. While variation exists among all Holocene H. sapiens, highly terrestrially mobile Later Stone Age (LSA) southern Africans and cross-country runners display the highest relative tibial rigidity, while maritime Andaman Islanders and swimmers display the lowest, with controls falling between. All fossil hominins displayed relative tibial rigidity that exceeded, or was similar to, the highly terrestrially mobile Later Stone Age southern Africans and modern human cross-country runners. The more extreme skeletal structure of most Neandertals and Levantine H. sapiens, as well as the odd Upper Palaeolithic individual, appears to reflect adaptation to intense and/or highly repetitive lower limb (relative to upper limb) loading. This loading may have been associated with bipedal travel, and appears to have been more strenuous than that encountered by even university varsity runners, and Holocene foragers with hunting grounds 2000-3000 square miles in size. Skeletal variation among the athletes and foraging groups is consistent with known or inferred activity profiles, which support the position that the Pleistocene remains reflect adaptation to extremely active and mobile lives. Copyright © 2013 Elsevier Ltd. All rights reserved.

[APPLICATION OF V-Y ADVANCED SENSE-REMAINED POSTERIOR TIBIAL ARTERY PERFORATOR FLAP IN REPAIRING WOUND AROUND ANKLE].

PubMed

Tang, Xiujun; Wang, Bo; Wei, Zairong; Wang, Dali; Han, Wenjie; Zhang, Wenduo; Li, Shujun

2015-12-01

OBJECTIVE To explore the feasibility and effectiveness of V-Y advanced sense-remained posterior tibial artery perforator flap in repairing wound around the ankle. METHODS Between March 2012 and January 2015, 11 patients with wounds around the ankle were treated by V-Y advanced sense-remained posterior tibial artery perforator flap. There were 6 males and 5 females with a median age of 37 years (range, 21-56 years). The causes were traffic accident injury in 3 cases, thermal injury in 2 cases, burn in 2 cases, iatrogenic wounds in 2 cases, and local contusion in 2 cases. The disease duration ranged from 1 to 3 weeks (mean, 2 weeks). Injury was located at the medial malleolus in 4 cases, at the lateral malleolus in 3 cases, and at the heel in 4 cases. All had exposure of bone, tendon, or plate. The defect area ranged from 4 cmx2 cm to 5 cmx3 cm; the area of the flap ranged from 11 cmx4 cm to 15 cmx6 cm. Necrosis of distal flap occurred in 1 case after operation; re-operation to amputate the posterior tibial artery was given and the wound was repaired by proximal skin graft. Light necrosis of distal end was observed in 2 cases, and wound healed at 3 weeks after dressing. And other flaps successfully survived, and primary healing of wounds were obtained. The patients were followed up 6-24 months (mean, 11 months). The flaps were good in color, texture, and appearance. The ankle joint had normal activity. At last follow-up, 10 cases restored fine sense, and 1 case restored protective feeling with posterior tibial artery advanced flap after amputation. V-Y advanced sense-remained posterior tibial artery perforator flap has the advantages of reliable blood supply, simple operation, good appearance, and sensory recovery. Therefore, it is an ideal method to repair wound around the ankle.

Tibial shaft fractures in football players

PubMed Central

Chang, Winston R; Kapasi, Zain; Daisley, Susan; Leach, William J

2007-01-01

Background Football is officially the most popular sport in the world. In the UK, 10% of the adult population play football at least once a year. Despite this, there are few papers in the literature on tibial diaphyseal fractures in this sporting group. In addition, conflicting views on the nature of this injury exist. The purpose of this paper is to compare our experience of tibial shaft football fractures with the little available literature and identify any similarities and differences. Methods and Results A retrospective study of all tibial football fractures that presented to a teaching hospital was undertaken over a 5 year period from 1997 to 2001. There were 244 tibial fractures treated. 24 (9.8%) of these were football related. All patients were male with a mean age of 23 years (range 15 to 29) and shin guards were worn in 95.8% of cases. 11/24 (45.8%) were treated conservatively, 11/24 (45.8%) by Grosse Kemp intramedullary nail and 2/24 (8.3%) with plating. A difference in union times was noted, conservative 19 weeks compared to operative group 23.9 weeks (p < 0.05). Return to activity was also different in the two groups, conservative 27.6 weeks versus operative 23.3 weeks (p < 0.05). The most common fracture pattern was AO Type 42A3 in 14/24 (58.3%). A high number 19/24 (79.2%) were simple transverse or short oblique fractures. There was a low non-union rate 1/24 (4.2%) and absence of any open injury in our series. Conclusion Our series compared similarly with the few reports available in the literature. However, a striking finding noted by the authors was a drop in the incidence of tibial shaft football fractures. It is likely that this is a reflection of recent compulsory FIFA regulations on shinguards as well as improvements in the design over the past decade since its introduction. PMID:17567522

Relationship between Widening and Position of the Tunnels and Clinical Results of Anterior Cruciate Ligament Reconstruction to Knee Osteoarthritis: 30 Patients at a Minimum Follow-Up of 10 Years.

PubMed

Ayala-Mejias, Juan Diego; Garcia-Gonzalez, Benjamin; Alcocer-Perez-España, Luis; Villafañe, Jorge Hugo; Berjano, Pedro

2017-07-01

To evaluate the relationship between tunnel position and widening and long-term clinical results in anterior cruciate ligament (ACL) reconstruction, a retrospective cohort of 30 patients undergoing ACL reconstruction with double semitendinous plus double gracilis (SAC technique) with longer than 10-year follow-up was selected. CT scans in the first 3 months and at final follow-up was evaluated. Position, angle, and widening of tunnels including Nebelung criteria were recorded in all CT scans. Physical, KT-1000, and clinical evaluation were performed at final follow-up. Outcomes and knee arthritis severity were evaluated at final follow-up. Mean follow-up was 11.2 ± 1.2. At final follow-up, 85 and 57% of tibial and femoral tunnels, respectively, developed some degree of enlargement. Frontal tibial angle (mean) was 72°, sagittal tibial angle 63°, frontal femoral angle 47°, sagittal femoral angle 20°, and tunnels divergence angle 36°. Preoperatively, KT-1000 30L and Lachman test scores were 5.52 and 5.79 respectively. In the last follow-up, 30L and manual Lachman test scores were 0.97 and 1.13, respectively ( p  < 0.001). In IKDC scale, pivot shift and Jerk tests showed 83 and 84% grade A results, respectively ( p  < 0.0001). In Fairbank scale, 23% worsened one grade and 27% worsened more than one grade ( p  < 0.005). Tibial tunnels widened more than femoral tunnels and further dilatation was found between intermediate and final follow-up. Higher incidence of tibial tunnel widening was observed in patients with tunnel verticalization. Tibial tunnel dilation was associated with long-term degenerative changes but not with final knee instability. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Force measurements in the medial meniscus posterior horn attachment: effects of anterior cruciate ligament removal.

PubMed

Markolf, Keith L; Jackson, Steven R; McAllister, David R

2012-02-01

Tears of the medial meniscus posterior horn attachment (PHA) occur clinically, and an anterior cruciate ligament (ACL)-deficient knee may be more vulnerable to this injury. The PHA forces from applied knee loadings will increase after removal of the ACL. Controlled laboratory study. A cap of bone containing the medial meniscus PHA was attached to a load cell that measured PHA tensile force. Posterior horn attachment forces were recorded before and after ACL removal during anteroposterior (AP) laxity testing at ±200 N and during passive knee extension tests with 5 N·m tibial torque and varus-valgus moment. Selected tests were also performed with 500 N joint load. For AP tests with no joint load, ACL removal increased laxity between 0° and 90° and increased PHA force generated by applied anterior tibial force between 30° and 90°. For AP tests with an intact ACL, application of joint load approximately doubled PHA forces. Anteroposterior testing of ACL-deficient knees was not possible with joint load because of bone cap failures from high PHA forces. Removal of the ACL during knee extension tests under joint load significantly increased PHA forces between 20° and 90° of flexion. For unloaded tests with applied tibial torque and varus-valgus moment, ACL removal had no significant effect on PHA forces. Applied anterior tibial force and external tibial torque were loading modes that produced relatively high PHA forces, presumably by impingement of the medial femoral condyle against the medial meniscus posterior horn rim. Under joint load, an ACL-deficient knee was particularly susceptible to PHA injury from applied anterior tibial force. Because tensile forces developed in the PHA are also borne by meniscus tissue near the attachment site, loading mechanisms that produce high PHA forces could also produce complete or partial radial tears near the posterior horn, a relatively common clinical observation.

Negative pressure wound therapy for Gustilo Anderson grade IIIb open tibial fractures.

PubMed

Park, Chul Hyun; Shon, Oog Jin; Kim, Gi Beom

2016-09-01

Traditionally, Gustilo Anderson grade IIIb open tibial fractures have been treated by initial wide wound debridement, stabilization of fracture with external fixation, and delayed wound closure. The purpose of this study is to evaluate the clinical and radiological results of staged treatment using negative pressure wound therapy (NPWT) for Gustilo Anderson grade IIIb open tibial fractures. 15 patients with Gustilo Anderson grade IIIb open tibial fractures, treated using staged protocol by a single surgeon between January 2007 and December 2011 were reviewed in this retrospective study. The clinical results were assessed using a Puno scoring system for severe open fractures of the tibia at the last followup. The range of motion (ROM) of the knee and ankle joints and postoperative complication were evaluated at the last followup. The radiographic results were assessed using time to bone union, coronal and sagittal angulations and a shortening at the last followup. The mean score of Puno scoring system was 87.4 (range 67-94). The mean ROM of the knee and ankle joints was 121.3° (range 90°-130°) and 37.7° (range 15°-50°), respectively. Bone union developed in all patients and the mean time to union was 25.3 weeks (range 16-42 weeks). The mean coronal angulation was 2.1° (range 0-4°) and sagittal was 2.7° (range 1-4°). The mean shortening was 4.1 mm (range 0-8 mm). Three patients had partial flap necrosis and 1 patient had total flap necrosis. There was no superficial and deep wound infection. Staged treatment using NPWT decreased the risks of infection and requirement of flap surgeries in Gustilo Anderson grade IIIb open tibial fractures. Therefore, staged treatment using NPWT could be a useful treatment option for Gustilo Anderson grade IIIb open tibial fractures.

Individual risk factors for deep infection and compromised fracture healing after intramedullary nailing of tibial shaft fractures: a single centre experience of 480 patients.

PubMed

Metsemakers, W-J; Handojo, K; Reynders, P; Sermon, A; Vanderschot, P; Nijs, S

2015-04-01

Despite modern advances in the treatment of tibial shaft fractures, complications including nonunion, malunion, and infection remain relatively frequent. A better understanding of these injuries and its complications could lead to prevention rather than treatment strategies. A retrospective study was performed to identify risk factors for deep infection and compromised fracture healing after intramedullary nailing (IMN) of tibial shaft fractures. Between January 2000 and January 2012, 480 consecutive patients with 486 tibial shaft fractures were enrolled in the study. Statistical analysis was performed to determine predictors of deep infection and compromised fracture healing. Compromised fracture healing was subdivided in delayed union and nonunion. The following independent variables were selected for analysis: age, sex, smoking, obesity, diabetes, American Society of Anaesthesiologists (ASA) classification, polytrauma, fracture type, open fractures, Gustilo type, primary external fixation (EF), time to nailing (TTN) and reaming. As primary statistical evaluation we performed a univariate analysis, followed by a multiple logistic regression model. Univariate regression analysis revealed similar risk factors for delayed union and nonunion, including fracture type, open fractures and Gustilo type. Factors affecting the occurrence of deep infection in this model were primary EF, a prolonged TTN, open fractures and Gustilo type. Multiple logistic regression analysis revealed polytrauma as the single risk factor for nonunion. With respect to delayed union, no risk factors could be identified. In the same statistical model, deep infection was correlated with primary EF. The purpose of this study was to evaluate risk factors of poor outcome after IMN of tibial shaft fractures. The univariate regression analysis showed that the nature of complications after tibial shaft nailing could be multifactorial. This was not confirmed in a multiple logistic regression model, which only revealed polytrauma and primary EF as risk factors for nonunion and deep infection, respectively. Future strategies should focus on prevention in high-risk populations such as polytrauma patients treated with EF. Copyright © 2014 Elsevier Ltd. All rights reserved.

Total knee arthroplasty in patients with a prior fracture of the tibial plateau.

PubMed

Weiss, Nicholas G; Parvizi, Javad; Trousdale, Robert T; Bryce, Rex D; Lewallen, David G

2003-02-01

A fracture of the tibial plateau may predispose the knee to the development of posttraumatic arthritis. Malunion, intra-articular chondro-osseous defects, limb malalignment, retained internal fixation devices, and poor surrounding soft tissues may in turn compromise the outcome of total knee arthroplasty. The aim of our study was to evaluate the results of total knee arthroplasty in patients with a previous fracture of the tibial plateau. The results of sixty-two condylar total knee arthroplasties performed with cement, from 1988 to 1999, in sixty-two patients with a previous fracture of the tibial plateau were reviewed. The fracture of the tibial plateau had been treated by open reduction and internal fixation in thirty-eight knees, external fixation in one knee, and nonoperatively in twenty-three knees. There were forty women and twenty-two men with an average age of sixty-three years at the time of the arthroplasty. Knee Society scores were recorded preoperatively and at the time of follow-up, at an average of 4.7 years, and complications were noted. No patient was lost to follow-up. The mean Knee Society scores improved significantly (p < 0.0001), from 43.9 points for pain and 52 points for function preoperatively to 82.9 and 84 points, respectively, at the time of the latest follow-up. There were thirteen reoperations, which included manipulation with the patient under anesthesia (five knees), wound revision (three knees), and component revision (five knees). There were six intraoperative complications (10%). A postoperative complication occurred in sixteen knees (26%). The vast majority of patients treated with total knee arthroplasty after a previous fracture of the tibial plateau have substantial improvement in function and relief of pain. However, these patients are at increased risk for perioperative complications, as evidenced by the high reoperation rate of 21% in this study.

Does increased topside conformity in modular total knee arthroplasty lead to increased backside wear?

PubMed

Schwarzkopf, Ran; Scott, Richard D; Carlson, Evan M; Currier, John H

2015-01-01

Modular metal-backed tibia components allow surgeons intraoperative flexibility. Although it is known that modular tibia components introduce the possibility for backside wear resulting from relative motion between the polyethylene insert and the tibial baseplate, it is not known to what degree variability in the conformity of the tibial polyethylene liner itself might contribute to backside wear. The purpose of this study was to determine whether a flat, cruciate-retaining tibial polyethylene bearing generates less backside wear than a more conforming (curved) tibial polyethylene bearing in an analysis of specimens explanted during revision surgery. The study included 70 total knee inserts explanted at revision surgery, all implanted and explanted by the same surgeon. Two different cruciate-retaining insert options in an otherwise similar knee system were used: one with a curved-on-flat (17) articular geometry and one with a highly conforming curved-on-curved design (53); both groups were sequential cohorts. The composite backside wear depth for the insert as well as the volume of backside wear was measured and compared between groups. The median linear backside-normalized wear for the posterior lipped inserts was 0.0063 mm/year (range, 0-0.085 mm/year), which was lower than for the curved inserts at 0.05 mm/year (range, 0.00003-0.14 mm/year) (p<0.001). The median calculated volumetric backside-normalized wear for the posterior lipped inserts was 14.2 mm3/year (range, 0-282.8 mm3/year) compared with 117 mm3/year (range, 2.1-312 mm3/year) for the curved inserts (p<0.001). In this retrieval study, more conforming tibial inserts demonstrated more backside-normalized wear than the flatter designs. This suggests that in this modular total knee arthroplasty design, higher articular conformity to address the issues of high bearing contact stress comes at a price: increased torque transmitted to the backside insert-to-tray interface. We suggest further work be undertaken to examine newer insert designs to evaluate if our conclusions hold true with the newer generation locking mechanism, tibial tray finish and polyethylene designs, as more highly conforming tibial inserts are introduced into the market. Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Patient reported health related quality of life early outcomes at 12 months after surgically managed tibial plafond fracture.

PubMed

Bonato, Luke J; Edwards, Elton R; Gosling, Cameron McR; Hau, Raphael; Hofstee, Dirk Jan; Shuen, Alex; Gabbe, Belinda J

2017-04-01

Tibial plafond fractures represent a small but complex subset of fractures of the lower limb. The aim of this study was to describe the health related quality of life, pain and return to work outcomes 12 months following surgically managed tibial plafond fracture. The Victorian Orthopaedic Trauma Outcomes Registry (VOTOR) database was used to identify patients with tibial plafond fractures. All patients captured by VOTOR with a tibial plafond fracture between September 2003 and July 2009, were identified consecutively and comprised the initial cohort. The radiographs of all identified patients were classified using the AO/OTA fracture classification. A review of the included patient's medical records was performed. Data were collected on the injury event, management and complications. Outcomes at 12 months were prospectively collected by telephone interview and included return to work, a numerical rating scale for assessment of pain and the Short Form 12 (SF-12). There were 98 unilateral tibial plafond fractures; 91 fractures were managed operatively, 4 non-operatively and 3 underwent amputation. The 91 operatively managed patients were the focus of this study. A two-stage management approach, involving temporary external fixation, followed by definitive open reduction and internal fixation, was the most common operative treatment. The follow-up rate at 12 months was 70%. 57% had returned to work by 12 months post-injury, the median (IQR) pain score was 2 (0-5) and 27% reported moderate to severe persistent pain. Mean PCS-12 scores were significantly lower than Australian norms (p=0.99), 38.2 for males and 37.5 for females. The presence of persistent pain, loss of physical health and a low return to work rate highlights the profound impact of tibial plafond fractures on patients' lives. Although this study looked at the early 12 month results, it is expected these outcomes will continue to improve over time. Further studies, with larger patient numbers, must focus on how to improve not only the operative management of these fractures, but also patient's mental and overall physical health in the long term. Improved management techniques and early identification of injury patterns known to perform poorly may help long-term outcomes. Copyright © 2016. Published by Elsevier Ltd.

[Close reduction combined with minimally invasive percutaneous plate osteosynthesis for proximal and distal tibial fractures: a report of 56 patients].

PubMed

Liu, Yin-Wen; Kuang, Yong; Gu, Xin-Feng; Zheng, Yu-Xin; Li, Zhi-Qiang; Wei, Xiao-En; Zhang, Ming-Cai; Zhan, Hong-Sheng; Shi, Yin-yu

2013-03-01

To evaluate the clinical effects of close reduction combined with minimally invasive percutanous plate osteosynthesis (MIPPO) for proximal and distal tibial fractures. From March 2007 to December 2010, 56 patients with proximal and distal tibial fractures were treated with close reduction combined with MIPPO technique. There were 39 males and 17 females,aged from 22 to 67 years with an average of 41.3 years. Left fracture was in 25 cases and right fracture was in 31 cases; proximal tibial fracture was in 15 cases and distal tibial fractures was in 41 cases; 34 cases caused by fall down and 22 cases caused by road accident. The mean time from injury to operation was 1.7 d. Clinical manifestation included pain, swelling of leg with limitation of activity. According to the standard of Johner-Wruhs, clinical effects were evaluated. The mean operative time was 46 min in 56 patients. All fractures obtained satisfactory reduction and the location of plate was good. Incisions healed with one-stage and no superficial or deep infection was found. All the patients were followed up from 8 to 23 months with an average of 14.2 months. Only one fracture complication with delayed union,and after auto grafting with ilium bone,the fracture got union. Other 55 cases obtained bone healing in 15 to 20 weeks after operation and no internal fixation failure was found. The time of walking was 4-6 months after operation,without limping at 7 months after operation. Both lower extremities were symmetrical and the function of knee and ankle got complete recovery. According to the criteria of Johner-Wruhs score,46 cases obtained excellent results,9 good and 2 fair. Treatment of proximal and distal tibial fractures with close reduction and MIPPO technique can not only preserve soft tissue,simplify operative procedure and decrease wound, but also can obtain rigid internal fixation and guarantee early function exercises of knee and ankle joints. The method has the advantages of less soft tissue injury, less blood loss, reliable fixation, which is effective method in treating proximal and distal tibial fractures and corresponds with the standpoint of biological fixation.

A Biomechanical Study of Posteromedial Tibial Plateau Fracture Stability: Do They All Require Fixation?

PubMed

Cuéllar, Vanessa G; Martinez, Danny; Immerman, Igor; Oh, Cheongeun; Walker, Peter S; Egol, Kenneth A

2015-07-01

Although the posteromedial fragment in tibial plateau fractures is often considered unstable, biomechanical evidence supporting this view is lacking. We aimed to evaluate the stability of the fragment in a cadaver model. Our hypothesis was that under the expected small axial force during rehabilitation and the combined effects of this force with shear force, internal rotation torque, and varus moment, the most common posteromedial tibial fragment morphology could maintain stability in early flexion. Axial compression force alone or combined with posterior shear, internal rotation torque, or varus moment was applied to the femurs of 5 fresh cadaveric knees. A Tekscan pressure mapping system was used to measure pressure and contact area between the femoral condyles, meniscus, and tibial plateau. A Microscribe 3D digitizer was used to define the 3-dimensional positions of the femur and tibia. A 10-mm and then a 20-mm osteotomy was created with a saw at an angle of 30 degrees in the axial plane with respect to the tangent of the posterior tibial plateau and 75 degrees in the sagittal plane, representing a typical posteromedial fracture fragment. At each flexion angle (15, 30, 60, 90, and 120 degrees) and loading condition (axial compression only, compression with shear force, torque, and varus moment), distal displacement of the medial femoral condyle and the tibial fracture fragments was determined. For the 10-mm fragment, medial femoral condyle displacement was little affected up to approximately 30-degree flexion, after which it increased. For the 20-mm fragment, there was progressive medial femoral condyle displacement with increasing flexion from baseline. However, for the 10- and 20-mm fragments themselves, displacements were noted at every flexion angle, starting at 1.7 mm inferior displacement with 15 degrees of flexion and internal rotation torque and up to 10.2 mm displacement with 90 degrees of flexion and varus bending moment. In this cadaveric model of a posteromedial tibial plateau fracture, both fracture fragments studied displaced with knee flexion, even at low flexion angles. Although such fragments may initially seem nondisplaced after injury, posteromedial fragments similar to these tested are likely to displace during knee range of motion exercises in non-weight-bearing conditions.

Acceleration of polarized protons and deuterons in the ion collider ring of JLEIC

NASA Astrophysics Data System (ADS)

Kondratenko, A. M.; Kondratenko, M. A.; Filatov, Yu N.; Derbenev, Ya S.; Lin, F.; Morozov, V. S.; Zhang, Y.

2017-07-01

The figure-8-shaped ion collider ring of Jefferson Lab Electron-Ion Collider (JLEIC) is transparent to the spin. It allows one to preserve proton and deuteron polarizations using weak stabilizing solenoids when accelerating the beam up to 100 GeV/c. When the stabilizing solenoids are introduced into the collider’s lattice, the particle spins precess about a spin field, which consists of the field induced by the stabilizing solenoids and the zero-integer spin resonance strength. During acceleration of the beam, the induced spin field is maintained constant while the resonance strength experiences significant changes in the regions of “interference peaks”. The beam polarization depends on the field ramp rate of the arc magnets. Its component along the spin field is preserved if acceleration is adiabatic. We present the results of our theoretical analysis and numerical modeling of the spin dynamics during acceleration of protons and deuterons in the JLEIC ion collider ring. We demonstrate high stability of the deuteron polarization in figure-8 accelerators. We analyze a change in the beam polarization when crossing the transition energy.

Acceleration of polarized protons and deuterons in the ion collider ring of JLEIC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kondratenko, A.; Kondratenko, M.; Filatov, Yu. N.

2017-07-01

The figure-8-shaped ion collider ring of Jefferson Lab Electron-Ion Collider (JLEIC) is transparent to the spin. It allows one to preserve proton and deuteron polarizations using weak stabilizing solenoids when accelerating the beam up to 100 GeV/c. When the stabilizing solenoids are introduced into the collider's lattice, the particle spins precess about a spin field, which consists of the field induced by the stabilizing solenoids and the zero-integer spin resonance strength. During acceleration of the beam, the induced spin field is maintained constant while the resonance strength experiences significant changes in the regions of "interference peaks". The beam polarization dependsmore » on the field ramp rate of the arc magnets. Its component along the spin field is preserved if acceleration is adiabatic. We present the results of our theoretical analysis and numerical modeling of the spin dynamics during acceleration of protons and deuterons in the JLEIC ion collider ring. We demonstrate high stability of the deuteron polarization in figure-8 accelerators. We analyze a change in the beam polarization when crossing the transition energy.« less

15 Years of R&D on high field accelerator magnets at FNAL

DOE PAGES

Barzi, Emanuela; Zlobin, Alexander V.

2016-07-01

The High Field Magnet (HFM) Program at Fermi National Accelerator Laboratory (FNAL) has been developing Nb 3Sn superconducting magnets, materials and technologies for present and future particle accelerators since the late 1990s. This paper summarizes the main results of the Nb 3Sn accelerator magnet and superconductor R&D at FNAL and outlines the Program next steps.

Electron acceleration by turbulent plasmoid reconnection

NASA Astrophysics Data System (ADS)

Zhou, X.; Büchner, J.; Widmer, F.; Muñoz, P. A.

2018-04-01

In space and astrophysical plasmas, like in planetary magnetospheres, as that of Mercury, energetic electrons are often found near current sheets, which hint at electron acceleration by magnetic reconnection. Unfortunately, electron acceleration by reconnection is not well understood yet, in particular, acceleration by turbulent plasmoid reconnection. We have investigated electron acceleration by turbulent plasmoid reconnection, described by MHD simulations, via test particle calculations. In order to avoid resolving all relevant turbulence scales down to the dissipation scales, a mean-field turbulence model is used to describe the turbulence of sub-grid scales and their effects via a turbulent electromotive force (EMF). The mean-field model describes the turbulent EMF as a function of the mean values of current density, vorticity, magnetic field as well as of the energy, cross-helicity, and residual helicity of the turbulence. We found that, mainly around X-points of turbulent reconnection, strongly enhanced localized EMFs most efficiently accelerated electrons and caused the formation of power-law spectra. Magnetic-field-aligned EMFs, caused by the turbulence, dominate the electron acceleration process. Scaling the acceleration processes to parameters of the Hermean magnetotail, electron energies up to 60 keV can be reached by turbulent plasmoid reconnection through the thermal plasma.

Wilson Prize Talk

NASA Astrophysics Data System (ADS)

Symon, Keith R.

2005-04-01

In the late 1950's and the 1960's the MURA (Midwestern Universities Research Association) working group developed fixed field alternating gradient (FFAG) particle accelerators. FFAG accelerators are a natural corollary of the invention of alternating gradient focusing. The fixed guide field accommodates all orbits from the injection to the final energy. For this reason, the transverse motion in the guide field is nearly decoupled from the longitudinal acceleration. This allows a wide variety of acceleration schemes, using betatron or rf accelerating fields, beam stacking, bucket lifts, phase displacement, etc. It also simplifies theoretical and experimental studies of accelerators. Theoretical studies included an extensive analysis of rf acceleration processes, nonlinear orbit dynamics, and collective instabilities. Two FFAG designs, radial sector and spiral sector, were invented. The MURA team built small electron models of each type, and used them to study orbit dynamics, acceleration processes, orbit instabilities, and space charge limits. A practical result of these studies was the invention of the spiral sector cyclotron. Another was beam stacking, which led to the first practical way of achieving colliding beams. A 50 MeV two-way radial sector model was built in which it proved possible to stack a beam of over 10 amperes of electrons.