Science.gov

Sample records for cemented tibial components

  1. Surface pretreatment for prolonged survival of cemented tibial prosthesis components: full- vs. surface-cementation technique

    PubMed Central

    Marx, Rudolf; Qunaibi, Mutaz; Wirtz, Dieter Christian; Niethard, Fritz Uwe; Mumme, Thorsten

    2005-01-01

    Background One of few persisting problems of cemented total knee arthroplasty (TKA) is aseptic loosening of tibial component due to degradation of the interface between bone cement and metallic tibial shaft component, particularly for surface cemented tibial components. Surface cementation technique has important clinical meaning in case of revision and for avoidance of stress shielding. Degradation of the interface between bone cement and bone may be a secondary effect due to excessive crack formation in bone cement starting at the opposite metallic surface. Methods This study was done to prove crack formation in the bone cement near the metallic surface when this is not coated. We propose a newly developed coating process by PVD layering with SiOx to avoid that crack formation in the bone cement. A biomechanical model for vibration fatigue test was done to simulate the physiological and biomechanical conditions of the human knee joint and to prove excessive crack formation. Results It was found that coated tibial components showed a highly significant reduction of cement cracking near the interface metal/bone cement (p < 0.01) and a significant reduction of gap formation in the interface metal-to-bone cement (p < 0.05). Conclusion Coating dramatically reduces hydrolytic- and stress-related crack formation at the prosthesis interface metal/bone cement. This leads to a more homogenous load transfer into the cement mantle which should reduce the frequency of loosening in the interfaces metal/bone cement/bone. With surface coating of the tibial component it should become possible that surface cemented TKAs reveal similar loosening rates as TKAs both surface and stem cemented. This would be an important clinical advantage since it is believed that surface cementing reduces metaphyseal bone loss in case of revision and stress shielding for better bone health. PMID:16262888

  2. Surface pretreatment for prolonged survival of cemented tibial prosthesis components: full- vs. surface-cementation technique.

    PubMed

    Marx, Rudolf; Qunaibi, Mutaz; Wirtz, Dieter Christian; Niethard, Fritz Uwe; Mumme, Thorsten

    2005-10-31

    One of few persisting problems of cemented total knee arthroplasty (TKA) is aseptic loosening of tibial component due to degradation of the interface between bone cement and metallic tibial shaft component, particularly for surface cemented tibial components. Surface cementation technique has important clinical meaning in case of revision and for avoidance of stress shielding. Degradation of the interface between bone cement and bone may be a secondary effect due to excessive crack formation in bone cement starting at the opposite metallic surface. This study was done to prove crack formation in the bone cement near the metallic surface when this is not coated. We propose a newly developed coating process by PVD layering with SiOx to avoid that crack formation in the bone cement. A biomechanical model for vibration fatigue test was done to simulate the physiological and biomechanical conditions of the human knee joint and to prove excessive crack formation. It was found that coated tibial components showed a highly significant reduction of cement cracking near the interface metal/bone cement (p < 0.01) and a significant reduction of gap formation in the interface metal-to-bone cement (p < 0.05). Coating dramatically reduces hydrolytic- and stress-related crack formation at the prosthesis interface metal/bone cement. This leads to a more homogenous load transfer into the cement mantle which should reduce the frequency of loosening in the interfaces metal/bone cement/bone. With surface coating of the tibial component it should become possible that surface cemented TKAs reveal similar loosening rates as TKAs both surface and stem cemented. This would be an important clinical advantage since it is believed that surface cementing reduces metaphyseal bone loss in case of revision and stress shielding for better bone health.

  3. 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

  4. Do bone loss and reconstruction procedures differ at revision of cemented unicompartmental knee prostheses according to the use of metal-back or all-polyethylene tibial component?

    PubMed

    Rouanet, T; Combes, A; Migaud, H; Pasquier, G

    2013-10-01

    Results of unicompartmental knee arthroplasty (UKA) revision are known but the severity of bone loss and the need for reconstruction are not detailed for different tibial implants. Metal-backing UKA revision exposes the patient to more severe tibial bone loss and requires more substantial reconstruction procedures than cemented polyethylene UKA revision. This retrospective series of 23 revisions of UKA to total knee arthroplasty (TKA) compared 11 all-polyethylene UKAs with 12 metal-backing UKAs. Factors that contributed to failure were aseptic loosening (n=12) and osteoarthritis evolution (n=11). Both groups were similar regarding the demographic and clinical features. We reported bone loss and the reconstruction procedure to fill it according to the initially used tibial implant. The results were evaluated with the IKS score to a follow-up of 37 months (range, 24-67 months). There were more tibial segmental bone loss (10 versus 3) and more metal wedges (8/12 versus 2/11) in metal-backing UKA revision (P<0.05). Tibial stems were more often used in metal-backing UKA revision (12/12 versus 7/11) (P=0.04). The results of TKA at follow-up did not differ according to whether the revised tibial implant was all polyethylene (IKS=155 [range, 107-195]) or metal-back (IKS=155 [range, 127-172]). This study suggests that metal-backing UKA revision exposes the patient to more severe tibial bone loss requiring more substantial reconstruction. These results must be confirmed on a larger population, but surgeons should be alerted to this kind of revision surgery, which warrants having available a revision knee prothesis. Level III, case-control study. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  5. The natural history of tibial radiolucent lines in a proximally cemented stemmed total knee arthroplasty.

    PubMed

    Smith, S; Naima, V S; Freeman, M A

    1999-01-01

    A total of 207 tibial components in total knee arthroplasty (TKA) have been reviewed at a maximum of 10 years after replacement. Twelve knees developed aseptic femoral loosening and were reviewed separately from the remaining 195. All tibial components were fixed with cement confined to the proximal surface of the implant combined with an uncemented stem. In the 195 TKAs with well-fixed femoral components and (presumably) low wear, 15% of tibiae developed early-onset, nonprogressive partial radiolucent lines (RLLs), typically in relation to preoperative sclerosis. Tibial component vertical migration was measured in 36 components: no migration was detected over the course of 5 years whether or not an RLL was present. There was no case of tibial osteolysis, no tibial component was revised for aseptic loosening, and no implant was radiologically loose. In 12 knees, the femoral component loosened with subsidence exposing peripheral bone that caused severe HDP wear. Tibial RLLs were present in 9, and osteolysis was present in 11 (although the tibial component was actually loose in only 1). This material has been used to study 1) the natural history of RLLs in cemented TKA and 2) the outcome of using cement confined to the proximal part of the tibial interface. We conclude that in low-wear prostheses RLLs are due to a failure to inject cement into sclerotic bone. Such lines are nonprogressive and do not affect fixation. In the presence of severe wear, however, they may provide a portal for the entry of debris into the interface causing progression of the RLL and lysis. Proximal cement plus an uncemented stem furnishes adequate tibial fixation, provided that the HDP wear rate is low.

  6. The Influence of Cement Morphology Parameters on the Strength of the Cement-Bone Interface in Tibial Tray Fixation.

    PubMed

    Nagel, Katrin; Bishop, Nicholas E; Schlegel, Ulf J; Püschel, Klaus; Morlock, Michael M

    2017-02-01

    The strength of the cement-bone interface in tibial component fixation depends on the morphology of the cement mantle. The purpose of this study was to identify thresholds of cement morphology parameters to maximize fixation strength using a minimum amount of cement. Twenty-three cadaveric tibiae were analyzed that had been implanted with tibial trays in previous studies and for which the pull-out strength of the tray had been measured. Specimens were separated into a group failing at the cement-bone interface (INTERFACE) and one failing in the bulk bone (BULK). Maximum pull-out strength corresponds to the ultimate strength of the bulk bone if the cement-bone interface is sufficiently strong. 3D models of the cement mantle in situ were reconstructed from computed tomography scans. The influences of bone mineral density and 6 cement morphology parameters (reflecting cement penetration, bone-cement interface, cement volume) on pull-out strength of the BULK group were determined using multiple regression analysis. The threshold of each parameter for classification of the specimens into either group was determined using receiver operating characteristic analysis. Cement penetration exceeding a mean of 1.1 mm or with a maximum of 5.6 mm exclusively categorized all BULK bone failure specimens. Failure strength of BULK failure specimens increased with bone mineral density (R 2  = 0.67, P < .001) but was independent of the cement morphology parameters. To maximize fixation strength, a mean cement penetration depth of at least 1.1 mm should be achieved during tibial tray cementing. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. The role of the cemented all-polyethylene tibial component in total knee replacement: a 30-year patient follow-up and review of the literature.

    PubMed

    Blumenfeld, Thomas J; Scott, Richard D

    2010-12-01

    Use of an all-polyethylene tibial component in primary total knee arthroplasty remains an attractive option considering the reported durability of the construct, the lowered cost compared to modular metal-backed tibia, and the elimination of backside wear. The two major intra-operative disadvantages include the inability to alter the tibial component thickness after permanent implant placement and the inability to use varus-valgus constrained designs. The long-term disadvantage is the inability to perform a modular insert exchange should this be required. We report the 30-year outcome of a single patient using the duopatellar total knee replacement system. Based on a critical review of the literature we would recommend use in patients 80 years of age or older, consideration in patients 75 to 79 years, and possibly in younger yet less active patients. These three groups would be the least likely to require a modular tibial liner exchange in their lifetime. Copyright © 2009 Elsevier B.V. All rights reserved.

  8. All-polyethylene tibial components generate higher stress and micromotions than metal-backed tibial components in total knee arthroplasty.

    PubMed

    Brihault, Jean; Navacchia, Alessandro; Pianigiani, Silvia; Labey, Luc; De Corte, Ronny; Pascale, Valerio; Innocenti, Bernardo

    2016-08-01

    Most total knee arthroplasty tibial components are metal-backed, but an alternative tibial component made entirely of polyethylene (all-polyethylene design) exists. While several clinical studies have shown that all-poly design performs similarly to the metal-backed, the objective of this study is to perform a biomechanical comparison. Loads, constraints and geometries during a squat activity at 120° of flexion were obtained from a validated musculoskeletal model and applied to a finite element model. Stresses in the tibia and micromotions at the bone-implant interface were evaluated for several implant configurations: (1) three different thicknesses of the cement penetration under the baseplate (2, 3 and 4 mm), (2) the presence or absence of a cement layer around the stem of the tibial tray and (3) three different bone conditions (physiological, osteopenic and osteoporotic bone). All-polyethylene tibial components resulted in significantly higher (p < 0.001) and more uneven stress distributions in the cancellous bone under the baseplate (peak difference: +128.4 %) and fivefold increased micromotions (p < 0.001). Performance of both implant designs worsened with poorer bone quality with peaks in stress and micromotion variations of +40.8 and +54.0 %, respectively (p < 0.001). Performance improvements when the stem was cemented were not statistically significant (n.s.). The metal-backed design showed better biomechanical performance during a squat activity at 120° of flexion compared to the all-polyethylene design. These results should be considered when selecting the appropriate tibial component for a patient, especially in the presence of osteoporotic bone or if intense physical activity is foreseen.

  9. Primary stability of tibial plateaus under dynamic compression-shear loading in human tibiae - Influence of keel length, cementation area and tibial stem.

    PubMed

    Grupp, Thomas M; Saleh, Khaled J; Holderied, Melanie; Pfaff, Andreas M; Schilling, Christoph; Schroeder, Christian; Mihalko, William M

    2017-07-05

    The objective of our study was to evaluate the impact of the tibial keel & stem length in surface cementation, of a full cemented keel and of an additional tibial stem on the primary stability of a posterior stabilised tibial plateau (VEGA® System Aesculap Tuttlingen, Germany) under dynamic compression-shear loading conditions in human tibiae. We performed the cemented tibial plateau implantations on 24 fresh-frozen human tibiae of a mean donor age of 70.7years (range 47-97). The tibiae were divided into four groups of matched pairs based on comparable trabecular bone mineral density. To assess the primary stability under dynamic compression shear conditions, a 3D migration analysis of the tibial component relative to the bone based on displacements and deformations and an evaluation of the cement layer including penetration was performed by CT-based 3D segmentation. Within the tested implant fixation principles the mean load to failure of a 28mm keel and a 12mm stem (40mm) was 4700±1149N and of a 28mm keel length was 4560±1429N (p=0.996), whereas the mean load to failure was 4920±691N in full cementation (p=0.986) and 5580±502N with additional stem (p=0.537), with no significant differences regarding the dynamic primary stability under dynamic compression-shear test conditions. From our observations, we conclude that there is no significant difference between a 40mm and a 28mm tibial keel & stem length and also between a surface and a full cementation in the effect on the primary stability of a posterior stabilised tibial plateau, in terms of failure load, migration characteristics and cement layer thickness including the penetration into the trabecular bone. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Low Rates of Aseptic Tibial Loosening in Obese Patients With Use of High-Viscosity Cement and Standard Tibial Tray: 2-Year Minimum Follow-Up.

    PubMed

    Crawford, David A; Berend, Keith R; Nam, Denis; Barrack, Robert L; Adams, Joanne B; Lombardi, Adolph V

    2017-09-01

    Total knee arthroplasty is overall a very successful surgery, but complications do occur. These complications include aseptic loosening of the tibial component, and obese patients are among the highest risk group. High-viscosity cement (HVC) has been implicated as a possible cause for aseptic loosening of the tibial component. The purpose of this study was to evaluate the incidence of aseptic loosening of the tibial component in obese patients with the use of HVC and standard tibial tray. We identified 1366 obese patients (1851 knees) with a body mass index >35 kg/m 2 and 2-year minimum follow-up who underwent primary total knee arthroplasty using HVC and a symmetrical, grit-blasted, cobalt-chrome tibial component with 40-mm stem. Preoperative and postoperative range of motion, Knee Society (KS) scores, complications, and reoperations were evaluated. Specifically, we assessed the rate of tibial aseptic loosening. At a mean 5.4 years follow-up, only 1 in 1851 knees had aseptic loosening of the tibial component for an incidence of 0.054%. There was a mean increase of 3.3 degrees of knee range of motion. KS pain level decreased by 38.6 points (50 point scale). KS clinical scores improved by 52.2, Knee Society functional scores improved by 19.5, University of California, Los Angeles, activity score improved by 0.9, and Oxford Knee Score by 15.7. All these improvements were statistically significant with P < .001. Standard tibial components and HVC can be used in most patients, including the high-risk obese group, with low rates of tibial aseptic loosening. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Shape optimization of tibial prosthesis components

    NASA Technical Reports Server (NTRS)

    Saravanos, D. A.; Mraz, P. J.; Davy, D. T.

    1993-01-01

    NASA technology and optimal design methodologies originally developed for the optimization of composite structures (engine blades) are adapted and applied to the optimization of orthopaedic knee implants. A method is developed enabling the shape tailoring of the tibial components of a total knee replacement implant for optimal interaction within the environment of the tibia. The shape of the implant components are optimized such that the stresses in the bone are favorably controlled to minimize bone degradation, to improve the mechanical integrity of the implant/interface/bone system, and to prevent failures of the implant components. A pilot tailoring system is developed and the feasibility of the concept is demonstrated and evaluated. The methodology and evolution of the existing aerospace technology from which this pilot optimization code was developed is also presented and discussed. Both symmetric and unsymmetric in-plane loading conditions are investigated. The results of the optimization process indicate a trend toward wider and tapered posts as well as thicker backing trays. Unique component geometries were obtained for the different load cases.

  12. Effect of tibial tray design on cement morphology in total knee arthroplasty.

    PubMed

    Schlegel, Ulf J; Püschel, Klaus; Morlock, Michael M; Nagel, Katrin

    2014-11-29

    Improvements to enforce primary fixation in cemented total knee arthroplasty have been suggested to be a key issue for long-term survival. In this context, it has been questioned whether specific implant design features influence bone cement morphology and hence primary interface strength. The purpose of this study was to investigate in vitro the influence of cement pockets on the tibial tray on cement penetration in the tibia. Eight paired cadaveric, human tibiae were available for investigation. One side of a pair was implanted with a fixed bearing tibial tray (FB) featuring cement pockets on the undersurface, while in the other side, a mobile bearing platform (MB) without cement pockets was used. Specimens underwent computed tomography analysis of the cement morphology as well as BMD assessment. While bone cement layer between implant and bone surface was thicker in the FB group (p = 0.032), bone cement penetration was not influenced by implant design (p = 0.529). The present study suggests that cement pockets do not alter or enforce bone cement penetration under the tibial tray in an in vitro scenario.

  13. Initial mechanical stability of cementless highly-porous titanium tibial components

    SciTech Connect

    Stone, Timothy Brandon; Amer, Luke D; Warren, Christopher P

    2008-01-01

    Cementless fixation in total knee replacement has seen limited use since reports of early failure surfaced in the late 80s and early 90s. However the emergence of improved biomaterials, particularly porous titanium and tantalum, has led to a renewed interest in developing a cementless tibial component to enhance long-term survivorship of the implants. Cement is commonly employed to minimize micromotion in new implants but represents a weak interface between the implant and bone. The elimination of cement and application of these new biomaterials, which theoretically provide improved stability and ultimate osseointegration, would likely result in greater knee replacement success. Additionally,more » the removal of cement from the procedure would help minimize surgical durations and get rid of the time needed for curing, thereby the chance of infection. The purpose of this biomechanical study was twofold. The first goal was to assess whether vibration analysis techniques can be used to evaluate and characterize initial mechanical stability of cementless implants more accurately than the traditional method of micromotion determination, which employs linear variable differential transducers (LVDTs). Second, an evaluative study was performed to determine the comparative mechanical stability of five designs of cementless tibial components under mechanical loading designed to simulate in vivo forces. The test groups will include a cemented Triathlon Keeled baseplate control group, three different 2-peg cementless baseplates with smooth, mid, and high roughnesses and a 4-peg cement/ess baseplate with mid-roughness.« less

  14. Initial mechanical stability of cementless highly-porous titanium tibial components

    SciTech Connect

    Stone, Timothy Brandon; Amer, Luke D; Warren, Christopher P; Cornwell, Phillip; Meneghini, R Michael

    2008-01-01

    Cementless fixation in total knee replacement has seen limited use since reports of early failure surfaced in the late 80s and early 90s. However the emergence of improved biomaterials, particularly porous titanium and tantalum, has led to a renewed interest in developing a cementless tibial component to enhance long-term survivorship of the implants. Cement is commonly employed to minimize micromotion in new implants but represents a weak interface between the implant and bone. The elimination of cement and application of these new biomaterials, which theoretically provide improved stability and ultimate osseointegration, would likely result in greater knee replacement success. Additionally, the removal of cement from the procedure would help minimize surgical durations and get rid of the time needed for curing, thereby the chance of infection. The purpose of this biomechanical study was twofold. The first goal was to assess whether vibration analysis techniques can be used to evaluate and characterize initial mechanical stability of cementless implants more accurately than the traditional method of micromotion determination, which employs linear variable differential transducers (LVDTs). Second, an evaluative study was performed to determine the comparative mechanical stability of five designs of cementless tibial components under mechanical loading designed to simulate in vivo forces. The test groups will include a cemented Triathlon Keeled baseplate control group, three different 2-peg cementless baseplates with smooth, mid, and high roughnesses and a 4-peg cement/ess baseplate with mid-roughness.

  15. Improving tibial component alignment in total knee arthroplasty.

    PubMed

    Cinotti, G; Sessa, P; D'Arino, A; Ripani, F R; Giannicola, G

    2015-12-01

    Tibia torsion may influence the accuracy of extramedullary instrumentations in total knee arthroplasty (TKA). This study assessed whether the effect of tibial torsion may be overcome using a surgical technique in which the extramedullary rod is aligned to reference points at the proximal tibia only. A consecutive series of 94 knees that underwent TKA were analyzed. In the first 47 knees (group 1), a standard procedure for tibial component alignment was performed while in the second group of 47 knees, a modified surgical technique was used including the alignment of the extramedullary rod to the reference points at the proximal tibia only (group 2). Lower limb, femoral, and tibial component alignment were measured on postoperative long-leg radiographs. Femorotibial mechanical axes angles were similar in the two groups. Femoral component alignment also did not differ between the groups. A neutral alignment of the tibial component was achieved in 17 and 34 % of the knees in group 1 and group 2, respectively (p = 0.04). A malalignment of the tibial component >3° was found in 34 % of knees in group 1 compared with 4 % of those in group 2 (p = 0.0001). Coronal alignment of the tibial component may improve by setting the extramedullary rod in line with anatomical references in the proximal tibia only. This technique appears to bypass the influence of tibial torsion on the alignment of the extramedullary guide at the distal tibia. The clinical relevance of the study is that using this technique, the rate of malalignment of the tibial component may be reduced compared to a standard technique in which a fixed reference is used at the ankle joint.

  16. Tibial component fixation with a peri-apatite coating: evaluation by radiostereometric analysis in a canine total knee arthroplasty model.

    PubMed

    Allen, Matthew J; Leone, Kendall A; Dunbar, Michael J; Race, Amos; Rosenbaum, Paula F; Sacks, Jonathan M

    2012-06-01

    Cementless fixation for the tibial component in total knee arthroplasty (TKA) remains problematic. Peri-Apatite (PA), a solution-deposited hydroxyapatite, is under investigation as an option for improving the fixation of cementless tibial components. In this study, radiostereometric analysis was used to document implant migration in 48 dogs that underwent TKA with cementless, PA-coated, or cemented tibial components. Migration at 12 weeks was similar in the 2 groups. At 12 months, there was greater migration in the PA-coated group, but the difference between the 2 groups was below the threshold considered clinically significant. In this canine TKA model, cementless fixation with PA performed less well than did cemented fixation, but not to a degree that would make a clinical difference in the short term. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. 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.

  18. Tibial component designs in primary total knee arthroplasty: should we reconsider all-polyethylene component?

    PubMed

    Cheng, Tao; Pan, Xiaoyun; Liu, Tao; Zhang, Xianlong

    2012-08-01

    Despite the frequency with which total knee arthroplasties (TKAs) are performed, whether they are best performed using all-polyethylene or metal-backed tibial components remains a controversy. The aim of the present study was to determine the advantages and disadvantages of metal-backed compared with all-polyethylene tibial components during TKAs through an evaluation of current literature. A meta-analysis and systematic review of randomized and non-randomized comparative studies comparing metal-backed with all-polyethylene tibial components during TKAs were performed. The focus of the analysis was on the outcomes of knee score, range of motion (ROM), quality of life, implant alignment, tibial migration, radiolucent line, complication, reoperation, and implant survivorship. A total of 10 randomized/quasi-randomized controlled trials and 13 non-randomized comparative studies assessing 19,767 TKAs were eligible. On the basis of these studies, no significant differences were found between the 2 groups with regard to knee score, ROM, quality of life, complication, and reoperation. The findings indicated that using all-polyethylene tibial components is associated with lower continuous migration rate compared with metal-backed tibial components. Only 13 studies provided adequate data on implant survivorship during intermediate or long-term follow-up. Of these, 9 found that no statistical significance existed between the 2 groups. The other 3 studies found that using all-polyethylene components yielded a higher survival rate than using metal-backed components. Metal-backed tibial components had no obvious advantages over all-polyethylene tibial components in TKAs. However, this finding should be interpreted with caution due to publication bias, low methodological quality of the included studies, and different surgical interventions. Therapeutic study (systematic review and meta-analysis), Level III.

  19. 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.

  20. Supramalleolar Osteotomy for Tibial Component Malposition in Total Ankle Replacement.

    PubMed

    Deforth, Manja; Krähenbühl, Nicola; Zwicky, Lukas; Knupp, Markus; Hintermann, Beat

    2017-09-01

    Persistent pain despite a total ankle replacement is not uncommon. A main source of pain may be an insufficiently balanced ankle. An alternative to the revision of the existing arthroplasty is the use of a corrective osteotomy of the distal tibia, above the stable implant. This strictly extraarticular procedure preserves the integrity of the replaced joint. The aim of this study was to review a series of patients in whom a corrective supramalleolar osteotomy was performed to realign a varus misaligned tibial component in total ankle replacement. We hypothesized that the supramalleolar osteotomy would correct the malpositioned tibial component, resulting in pain relief and improvement of function. Twenty-two patients (9 male, 13 female; mean age, 62.6 years; range, 44.7-80) were treated with a supramalleolar osteotomy to correct a painful ankle with a varus malpositioned tibial component. Prospectively recorded radiologic and clinical outcome data as well as complications and reoperations were analyzed. The tibial anterior surface angle significantly changed from 85.2 ± 2.5 degrees preoperatively to 91.4 ± 2.9 degrees postoperatively ( P < .0001), the American Orthopaedic Foot & Ankle Society hindfoot score significantly increased from 46 ± 14 to 66 ± 16 points ( P < .0001) and the patient's pain score measured with the visual analog scale significantly decreased from 5.8 ± 1.9 to 3.3 ± 2.4 ( P < .001). No statistical difference was found in the tibial lateral surface angle and the range of motion of the ankle when comparing the preoperative to the postoperative measurements. The osteotomy healed in all but 3 patients on first attempt. Fifteen patients (68%) were (very) satisfied, 4 moderately satisfied, and 3 patients were not satisfied with the result. The supramalleolar osteotomy was found to be a reliable treatment option for correcting the varus misaligned tibial component in a painful replaced ankle. However, nonunion (14%) should be mentioned as a

  1. 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

  2. Valgus subsidence of the tibial component in cementless Oxford unicompartmental knee replacement.

    PubMed

    Liddle, A D; Pandit, H G; Jenkins, C; Lobenhoffer, P; Jackson, W F M; Dodd, C A F; Murray, D W

    2014-03-01

    The cementless Oxford unicompartmental knee replacement has been demonstrated to have superior fixation on radiographs and a similar early complication rate compared with the cemented version. However, a small number of cases have come to our attention where, after an apparently successful procedure, the tibial component subsides into a valgus position with an increased posterior slope, before becoming well-fixed. We present the clinical and radiological findings of these six patients and describe their natural history and the likely causes. Two underwent revision in the early post-operative period, and in four the implant stabilised and became well-fixed radiologically with a good functional outcome. This situation appears to be avoidable by minor modifications to the operative technique, and it appears that it can be treated conservatively in most patients.

  3. Experience Influences the Agreement and Reliability of Tibial Component Positioning in Total Knee Arthroplasty.

    PubMed

    Amanatullah, Derek F; Pallante, Graham D; Ollivier, Matthieu P; Hooke, Alexander W; Abdel, Matthew P; Taunton, Michael J

    2017-11-13

    Poor rotation of the tibial component is associated with unfavorable total knee arthroplasty outcomes. Some surgeons utilize the tibial tubercle (TT method), while others utilize the femoral cam (Box method) as a rotational landmark during total knee arthroplasty. Our purpose is to determine the reproducibility of 2 methods for establishing intra-operative tibial component rotation, while also comparing the effect of level of training. Twelve surgeons positioned and sized a symmetric tibial component on 7 cadaver knees. Surgeons were allowed to utilize their preferred method for establishing tibial component rotation. Seven surgeons selected the TT method, 4 utilized the Box method, and 1 used both methods depending on the specimen. Repeat measurements were completed by each surgeon after a rest period. The differences between tibial tray positions were assessed using computer-assisted optoelectronic measurements. Intra-class correlation coefficients were calculated to determine inter-observer agreement (IOA) and intra-rater reliability (IRR). Overall, both the Box method and the TT method demonstrated high IRR for tibial component rotation. Experienced surgeons were more consistent at establishing component rotation regardless of technique. Trainees were more consistent when utilizing the Box method (IRR 0.96, IOA 0.94) than the TT method (IRR 0.71, IOA 0.72). Surgeon experience influences the agreement and reliability of tibial component position. For less experienced surgeons, the Box method was more effective than the TT method for consistently reproducing tibial component rotation. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Medial parapatellar approach leads to internal rotation of tibial component in total knee arthroplasty.

    PubMed

    Schiapparelli, Filippo-Franco; Amsler, Felix; Hirschmann, Michael T

    2017-05-30

    The purpose of this study was to investigate if the type of approach [medial parapatellar approach (MPA) versus lateral parapatellar approach with tibial tubercle osteotomy (LPA)] influences rotation of femoral and/or tibial component and leg axis in total knee arthroplasty (TKA). It was the hypothesis that MPA leads to an internally rotated tibial TKA component. This study included 200 consecutive patients in whom TKA was performed using either a parapatellar medial (n = 162, MPA) or parapatellar lateral approach with tibial tubercle osteotomy (n = 38, LPA). All patients underwent clinical follow-up, standardized radiographs and computed radiography (CT). TKA components' position and the whole leg axis were assessed on 3D reconstructed CT scans (sagittal, coronal and rotational). Mean values of TKA component position and the whole leg alignment of both groups were compared using a t test. The tibial component was graded as internally rotated (<3° of external rotation (ER)), neutral rotation (equal or between 3° and 6° of ER) and externally rotated (>6° ER). The femoral component was graded as internally rotated [>3° of internal rotation (IR)], neutral rotation (equal or between -3° IR and 3° of ER) and externally rotated (>3° ER). There was no significant difference in terms of whole leg axis after TKA between both groups (MPA: 0.2° valgus ± 3.4; LPA: 0.0° valgus ± 3.5). Means of tibial component rotation were 2.7° ER ± 6.1 (MPA) and 7.6° ER ± 5.4 (LPA). Patients of group LPA presented a significantly less internally rotated (LPA: 18.4%; MPA: 48.8%) and more externally rotated (LPA: 52.6%; MPA: 22.8%) tibial component (p < 0.001). No significant differences were seen for the femoral component position, tibial valgus/varus and tibial slope. The type of approach (medial versus lateral) significantly influenced tibial TKA component rotation. It appears that a MPA tends to internally rotate the tibial TKA component and a LPA tends to

  5. What mechanisms are associated with tibial component failure after kinematically-aligned total knee arthroplasty?

    PubMed

    Nedopil, Alexander J; Howell, Stephen M; Hull, Maury L

    2017-08-01

    Eight patients treated with kinematically-aligned (KA) total knee arthroplasty (TKA) presented with tibial component failure. We determined whether radiographic measurements and clinical characteristics are different between patients with and without tibial component failure to identify mechanisms of failure and strategies to reduce the risk. Out of 3,212 primary TKAs (2,725 TKAs with a two-year minimum follow up), of which all were performed with KA, eight patients presented with tibial component failure. Radiographic measurements, clinical characteristics (e.g. age, gender, BMI, etc.), revision surgical records, and Oxford knee scores were compared to control cohort patients matched 1:3. Tibial component failure presented at an average of 28 ± 15 months after primary TKA. Patients with tibial component failure had a 6 kg/m2 greater body mass index (p = 0.034) and 5° greater posterior slope of the tibia component (p = 0.002) than controls. Final follow-up averaged 56 ± 19 months after the primary TKA and 28 ± 24 months after the revision TKA. The final Oxford knee score was 39 ± 4.6 for patients with tibial component failure and 44 ± 6.5 for the controls (p = 0.005). The incidence of tibial component failure after KA TKA was 0.3% and was caused by posterior subsidence or posterior edge wear and not varus subsidence. The strategy for lowering the risk of tibial component failure when performing KA is to set the tibial component parallel to the flexion-extension plane (slope) and varus-valgus plane of the native joint line.

  6. Malrotated tibial component increases medial collateral ligament tension in total knee arthroplasty.

    PubMed

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

    2014-12-01

    Malrotation of the tibial component can lead to complications after total knee arthroplasty (TKA). Despite reports of internal rotation being associated with more severe pain or stiffness than external rotation, the biomechanical reasons remain largely unknown. We used a computer simulation model and evaluated traction forces in the lateral collateral ligament (LCL) and medial collateral ligament (MCL) with a malrotated tibial component during squatting. We also examined tibiofemoral and patellofemoral contact forces and stresses under similar conditions. A dynamic musculoskeletal knee model was simulated in three different constrained tibial geometries with a prototype component. The testing conditions were changed between 15° external and 15° internal rotation of the tibial component. With internal rotation of the tibial component, the MCL force increased progressively; the LCL force also increased, but only up to less than half of the MCL force values. A higher degree of constraint of the tibial component was associated with greater femoral rotational movement and higher MCL forces. The tibiofemoral and patellofemoral contact forces were not influenced by malrotation of the tibial component, but the contact stresses increased because of decreased contact area. This altered loading condition could cause patient complaints and polyethylene problems after TKA. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  7. Reproducibility and Precision of CT Scans to Evaluate Tibial Component Rotation.

    PubMed

    Amanatullah, Derek F; Ollivier, Matthieu P; Pallante, Graham D; Abdel, Matthew P; Clarke, Henry D; Mabry, Tad M; Taunton, Michael J

    2017-08-01

    Component rotation likely plays a greater role on the survivorship and outcomes of total knee arthroplasties than is currently known. Our goal was to evaluate the precision, interobserver reliability, and intrarater reliability of tibial component rotation as measured by computed tomography (CT) scan, regardless of measurement technique. Three fellowship-trained, academic arthroplasty surgeons independently measured tibial component rotation on CT scans of 62 total knee arthroplasties using their methods of choice. Measurements were repeated at least 2 weeks after the initial measurement. The precision of the measurements was assessed using a formal 8-step protocol as the gold standard. Intraclass correlation coefficients (ICCs) were calculated to evaluate precision, interobserver agreement, and intrarater reliability RESULTS: The interobserver agreement between the 3 surgeons for tibial component rotation was also moderate (ICC = 0.52). The intrarater reliability of tibial rotation was excellent (ICC = 0.81). Comparison of surgeons' measurement to a validated gold standard revealed only moderate precision for tibial component rotation (ICC = 0.64). Practicing surgeons measuring tibial rotation were internally consistent, but failed to demonstrate satisfactory precision and interobserver agreement. We support the adoption of standardized criteria for the measurement of tibial component rotation on CT scans. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. 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.

  9. Effect of femoro-tibial component size mismatch on outcome in primary total knee replacement.

    PubMed

    Heylen, Steven; Foubert, Knud; Van Haver, Annemieke; Nicolai, Paul

    2016-06-01

    Most total knee arthroplasty systems allow a degree of femoro-tibial component size mismatch. We aim to investigate the influence of size mismatch on outcome after primary total knee arthroplasty. We reviewed 332 patients with cruciate-retaining Genesis II total knee arthroplasty with regard to femoro-tibial component size mismatch and Oxford Knee Score (OKS). We evaluated effects of Body Mass Index, gender and patellar procedure. Minimum follow-up is five years. We divided patients into four groups (tibial component larger than femoral component, no mismatch, femoral component one size larger and femoral component two sizes larger than tibial component). There was no statistically significant difference in OKS between the four groups. Size mismatch did not have a statistical significant effect on OKS in a multivariate analysis. Women had mismatched components in 66% of all cases and men in 40% of all cases. Our study showed no statistically significant effect of femoro-tibial size mismatch on outcome after total knee replacement. Compared to men, women tend to have more component size mismatch. Level III, retrospective comparative study. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. The effect of tibial component sizing on patient reported outcome measures following uncemented total knee replacement.

    PubMed

    Abram, Simon G F; Marsh, Andrew G; Brydone, Alistair S; Nicol, Fiona; Mohammed, Aslam; Spencer, Simon J

    2014-10-01

    When performing total knee replacement (TKR), surgeons are required to decide on the most appropriate size of tibial component. As implants are predominantly selected from incremental sizes of a preferred design, it may be necessary for a surgeon to slightly under or oversize the component. There are concerns that overhang could lead to pain from irritation of soft tissues, and an undersized component could lead to subsidence and failure. Patient reported outcome measures were recorded in 154 TKRs at one year postoperatively (in 100 TKRs) and five years post-operatively (in 54 TKRs) in 138 patients. The Oxford Knee Score (OKS), WOMAC and SF-12 were recorded, and a composite pain score was derived from the OKS and WOMAC pain questions. Tibial component size and position were assessed on scaled radiographs and implants were grouped into anatomic sized tibial component (78 TKRs), undersized component (48 TKRs), minor overhang one to three mm (10 TKRs) or major overhang ≥ 3 mm (18 TKRs). There was no statistically significant difference between the mean post-operative OKS, WOMAC, SF-12 or composite pain score of each group. Furthermore, localisation of the site of pain did not correlate with medial or lateral overhang of the tibial component. Our results suggest that tibial component overhang or undersizing is not detrimental to outcome measures or pain. II. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Influence of Cements Containing Calcareous Fly Ash as a Main Component Properties of Fresh Cement Mixtures

    NASA Astrophysics Data System (ADS)

    Gołaszewski, Jacek; Kostrzanowska-Siedlarz, Aleksandra; Ponikiewski, Tomasz; Miera, Patrycja

    2017-10-01

    The main goal of presented research was to examine usability of cements containing calcareous fly ash (W) from technological point of view. In the paper the results of tests concerning the influence of CEM II and CEM IV cements containing fly ash (W) on rheological properties, air content, setting times and plastic shrinkage of mortars are presented and discussed. Moreover, compatibility of plasticizers with cements containing fly ash (W) was also studied. Additionally, setting time and hydration heat of cements containing calcareous fly ash (W) were determined. In a broader aspect, the research contributes to promulgation of the possibility of using calcareous fly ash (W) in cement and concrete technology, what greatly benefits the environment protection (utilization of waste fly ash). Calcareous fly ash can be used successfully as the main component of cement. Cements produced by blending with processed fly ash or cements produced by interginding are characterized by acceptable technological properties. In respect to CEM I cements, cements containing calcareous fly ash worsen workability, decrease air content, delay setting time of mixtures. Cements with calcareous fly ash show good compatibility with plasticizers.

  12. The all-polyethylene tibial component in primary total knee arthroplasty.

    PubMed

    Gioe, Terence J; Maheshwari, Aditya V

    2010-02-01

    Outcomes of total knee arthroplasties performed with modern all-polyethylene tibial components have been found to be comparable with or better than those of arthroplasties done with metal-backed modular components in numerous mid-to-long-term follow-up studies, radiostereometric analyses, and the few prospective randomized trials available. Advantages of an all-polyethylene tibial component over a metal-backed modular component include lower cost, avoidance of locking-mechanism issues and backside wear, and increased polyethylene thickness after identical bone resections. Disadvantages of an all-polyethylene tibial component compared with a metal-backed modular component include a lack of modularity, limiting intraoperative options; no option for liner removal in the setting of acute irrigation and débridement; and no option for late liner exchange. Primary total knee arthroplasty with a modern all-polyethylene design can be done in many patients, with substantial cost savings across the health-care system.

  13. Stable migration of peri-apatite-coated uncemented tibial components in a multicentre study.

    PubMed

    Dunbar, M J; Laende, E K; Collopy, D; Richardson, C G

    2017-12-01

    Hydroxyapatite coatings for uncemented fixation in total knee arthroplasty can theoretically provide a long-lasting biological interface with the host bone. The objective of this study was to test this hypothesis with propriety hydroxyapatite, peri-apatite, coated tibial components using component migration measured with radiostereometric analysis over two years as an indicator of long-term fixation. A total of 29 patients at two centres received uncemented PA-coated tibial components and were followed for two years with radiostereometric analysis exams to quantify the migration of the component. While there was significant variation in individual migration patterns, the overall migration of the tibial component in the study group demonstrated a pattern of initial migration followed by stabilisation after one year, with mean maximum total point motion (MTPM) of 0.02 mm (standard deviation (sd) 0.20) between one and two years post-operatively. The direction of greatest motion was subsidence, which stabilised at three months post-operatively (mean translation of 0.21 mm, sd 0.40). The tibial component migration pattern of stabilisation in the second post-operative year is indicative of successful long-term fixation for this PA-coated tibial component. Cite this article: Bone Joint J 2017;99-B:1596-1602. ©2017 The British Editorial Society of Bone & Joint Surgery.

  14. Evaluation of the rotational alignment of the tibial component in total knee arthroplasty: position prioritizing maximum coverage.

    PubMed

    Hirakawa, Masashi; Miyazaki, Masashi; Ikeda, Shinichi; Matsumoto, Yoshiki; Kondo, Makoto; Tsumura, Hiroshi

    2017-01-01

    The standard for rotational alignment of the tibial component in total knee arthroplasty (TKA) remains unclear. Cases often require positioning of the tibial component, prioritizing adequate coverage of resected bone surface rather than alignment with the tibial rotational axis. We investigated tibial component position in TKA, prioritizing maximum coverage of resected bone surface, and evaluated the correlation with the tibial anteroposterior (AP) axis. We analyzed preoperative computed tomography images for primary TKA in 106 cases and 157 knees, using three-dimensional planning software. Tibial component position prioritizing maximum coverage of resected bone surface was simulated, and results were compared with the AP axis. Rotational alignment angle was defined as that between a line perpendicular to the tibial AP axis and a line connecting the posterior edge of the tibial component. The simulated tibial component was more externally rotated by a mean 4.5° ± 4.2°. The alignment angle showed normal distribution, but variability was large, ranging from 5.1° internal rotation to 16.2° external rotation. In 138 of 157 (87.9 %) knees, the tibial component was positioned in the externally rotated position with respect to the AP axis. The tibial component was aligned within the medial one-third of the patellar tendon in 122 of 157 (77.7 %) knees. The tibial component aligned using coverage prioritizing was externally rotated, although large variability was observed. Rotational alignment was optimal in 79 % of cases when the tibial component was aligned with coverage prioritizing, but hyperexternal rotation was observed in patients with severe knee deformation.

  15. In vivo deterioration of tibial baseplate locking mechanisms in contemporary modular total knee components.

    PubMed

    Engh, G A; Lounici, S; Rao, A R; Collier, M B

    2001-11-01

    The results of recent studies documenting the backside wear of polyethylene inserts retrieved from total knee implants call into question the stability of the locking mechanisms of modular tibial components. Wear of the metal tibial baseplate suggests that the capture mechanisms of some modular fixed-bearing tibial components do not adequately restrict in vivo motion of the insert. The purposes of this study were (1) to present a method for evaluating locking-mechanism stability and (2) to investigate the stability of modular tibial components after an interval in vivo. We measured the anteroposterior and mediolateral motion between the polyethylene insert and the tibial tray in a variety of modular total knee tibial components. A uniaxial mechanical testing machine was used to evaluate the stability of ten unimplanted components (control group), fifteen implants obtained from patients who were undergoing revision total knee arthroplasty (revision group), and fifteen devices retrieved post mortem (autopsy group). We applied loads along the anteroposterior and mediolateral axes of the tibial component and recorded the maximum insert displacement that occurred. From this value, we calculated an insert-motion index, the magnitude of a two-dimensional vector that represented the total motion in the transverse plane. For the control group, the mean insert-motion index was 64 +/- 13 microm (range, 6 to 157 microm); for the revision group, it was 341 +/- 51 microm (range, 104 to 718 microm); and for the autopsy group, it was 380 +/- 45 microm (range, 122 to 657 microm). The insert-motion index for the control group was significantly lower than that for the revision group (p = 0.001) or autopsy group (p < 0.001). Motion between the polyethylene insert and the metal baseplate in contemporary modular tibial designs increases after a period of in vivo loading. Although there are several advantages to the use of modular tibial components, these advantages must be weighed

  16. Giant early components of somatosensory evoked potentials to tibial nerve stimulation in cortical myoclonus.

    PubMed

    Anzellotti, Francesca; Onofrj, Marco; Bonanni, Laura; Saracino, Antonio; Franciotti, Raffaella

    2016-01-01

    Enlarged cortical components of somatosensory evoked potentials (giant SEPs) recorded by electroencephalography (EEG) and abnormal somatosensory evoked magnetic fields (SEFs) recorded by magnetoencephalography (MEG) are observed in the majority of patients with cortical myoclonus (CM). Studies on simultaneous recordings of SEPs and SEFs showed that generator mechanism of giant SEPs involves both primary sensory and motor cortices. However the generator sources of giant SEPs have not been fully understood as only one report describes clearly giant SEPs following lower limb stimulation. In our study we performed a combined EEG-MEG recording on responses elicited by electric median and tibial nerve stimulation in a patient who developed consequently to methyl bromide intoxication CM with giant SEPs to median and tibial nerve stimuli. SEPs wave shapes were identified on the basis of polarity-latency components (e.g. P15-N20-P25) as defined by earlier studies and guidelines. At EEG recording, the SEP giant component did not appear in the latency range of the first cortical component for median nerve SEP (N20), but appeared instead in the range of the P37 tibial nerve SEP, which is currently identified as the first cortical component elicited by tibial nerve stimuli. Our MEG and EEG SEPs recordings also showed that components in the latency range of P37 were preceded by other cortical components. These findings suggest that lower limb P37 does not correspond to upper limb N20. MEG results confirmed that giant SEFs are the second component from both tibial (N43m-P43m) and median (N27m-P27m) nerve stimulation. MEG dipolar sources of these giant components were located in the primary sensory and motor area.

  17. Motion at the Tibial and Polyethylene Component Interface in a Mobile-Bearing Total Ankle Replacement.

    PubMed

    Lundeen, Gregory A; Clanton, Thomas O; Dunaway, Linda J; Lu, Minggen

    2016-08-01

    Normal biomechanics of the ankle joint includes sagittal as well as axial rotation. Current understanding of mobile-bearing motion at the tibial-polyethylene interface in total ankle arthroplasty (TAA) is limited to anterior-posterior (AP) motion of the polyethylene component. The purpose of our study was to define the motion of the polyethylene component in relation to the tibial component in a mobile-bearing TAA in both the sagittal and axial planes in postoperative patients. Patients who were a minimum of 12 months postoperative from a third-generation mobile-bearing TAA were identified. AP images were saved at maximum internal and external rotation, and the lateral images were saved in maximum plantarflexion and dorsiflexion. Sagittal range of motion and AP translation of the polyethylene component were measured from the lateral images. Axial rotation was determined by measuring the relative position of the 2 wires within the polyethylene component on AP internal and external rotation imaging. This relationship was compared to a table developed from fluoroscopic images taken at standardized degrees of axial rotation of a nonimplanted polyethylene with the associated length relationship of the 2 imbedded wires. Sixteen patients were included in this investigation, 9 (56%) were male and average age was 68 (range, 49-80) years. Time from surgery averaged 25 (range, 12-38) months. Total sagittal range of motion averaged 23±9 (range, 9-33) degrees. Axial motion for total internal and external rotation of the polyethylene component on the tibial component averaged 6±5 (range, 0-18) degrees. AP translation of the polyethylene component relative to the tibial component averaged 1±1 (range, 0-3) mm. There was no relationship between axial rotation or AP translation of the polyethylene component and ankle joint range of motion (P > .05). To our knowledge, this is the first investigation to measure axial and sagittal motion of the polyethylene component at the tibial

  18. The Mark Coventry Award: Trabecular metal tibial components were durable and reliable in primary total knee arthroplasty: a randomized clinical trial.

    PubMed

    Pulido, Luis; Abdel, Matthew P; Lewallen, David G; Stuart, Michael J; Sanchez-Sotelo, Joaquin; Hanssen, Arlen D; Pagnano, Mark W

    2015-01-01

    Although highly porous metals have demonstrated excellent bone ingrowth properties and so are an intriguing option for fixation in total knee arthroplasty (TKA), some surgeons are skeptical about the durability of uncemented tibial fixation and the potential for soft tissues to adhere to these porous metals and perhaps cause knee stiffness or pain. The purpose of this study was to compare, in the context of a randomized clinical trial, a highly porous metal tibia compared with a traditional modular cemented tibia in terms of survivorship, Knee Society scores, range of motion (ROM), and complications. From 2003 to 2006, 397 patients (age 67.8 ± 8.7 years; 54% female) were randomized to three groups: (1) traditional modular cemented tibia; (2) cemented highly porous metal tibia; and (3) uncemented highly porous metal tibia. The same posterior-stabilized femoral component and patella component were cemented in every case. Stratified randomization was done for surgeon, patient's age, sex, and body mass index. Survivorship at 5 years was compared between the groups, as were Knee Society scores, ROM, and complications. Radiographic assessment included alignment, radiolucency, and implant migration/loosening. Patients were followed until death, revision, or for a minimum of 2 years (mean, 5 years; range, 2-9 years). Four patients were lost to followup before 2 years. Highly porous metal tibias (both uncemented and cemented) were no different from traditional cemented modular tibial modular components in terms of survivorship at 5 years using a intention-to-treat analysis (96.8% [1]; 97.6% [2]; 96.7% [3]; p = 0.59). A per-protocol analysis revealed that no highly porous metal tibia was revised for aseptic loosening. Highly porous metal tibias performed comparably to traditional cemented modular tibias in terms of Knee Society scores, ROM, and the frequency of complications. At 5 years this randomized clinical trial demonstrated that highly porous metal tibias

  19. Surgical Navigation Improves the Precision and Accuracy of Tibial Component Alignment in Canine Total Knee Replacement.

    PubMed

    Peters, Kaleigh M; Hutter, Erin; Siston, Robert A; Bertran, Judith; Allen, Matthew J

    2016-01-01

    The goal of this study was to determine whether computer-assisted surgical navigation improves the accuracy of tibial component alignment in canine total knee replacement (TKR). Retrospective radiographic review and prospective ex vivo study. Canine TKR radiographs (n = 17 sets) and canine cadaveric stifles (n = 12). Radiographs from TKR surgical workshops were reviewed to determine the incidence and magnitude of tibial component malalignment. Tibial component alignment was compared after either standard ("surgeon-guided") component placement or computer-assisted ("navigation-guided") placement. Results were compared against the current recommendations of a neutral (0° varus-valgus) ostectomy in the frontal plane and 6° of caudal slope in the sagittal plane. A prospective cadaveric study was then undertaken by performing TKR in 12 canine stifle joints. Malalignment of >3° in the frontal and sagittal planes was identified in 12% and 24% of the radiographs from the retrospective review, respectively. Surgical navigation reduced both the mean error (P = .007) and the variability in frontal plane alignment (P < .001) as compared with surgeon-guided procedures. The mean error in sagittal plane alignment was not significantly different (P = .321), but variability in alignment was significantly lower when navigation was used (P = .008). Surgical navigation significantly improved accuracy and decreased variability in tibial component alignment in canine TKR. Clinical trials would be required to determine whether these improvements in surgical accuracy lead to better clinical outcomes in terms of joint function and a reduction in long-term implant wear. © Copyright 2015 by The American College of Veterinary Surgeons.

  20. 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.

  1. Tibial component rotation during the unicompartmental knee arthroplasty: is the anterior superior iliac spine an appropriate landmark?

    PubMed

    Lee, Seung-Yup; Chay, Suhwoo; Lim, Hong-Chul; Bae, Ji-Hoon

    2017-12-01

    No "ideal" landmark for tibial component rotation in medial unicompartmental knee arthroplasty (UKA) has been suggested by a biomechanical and clinical study. The aim of this study was to investigate whether the anterior superior iliac spine (ASIS) could provide a consistent rotational landmark of the tibial component during mobile-bearing medial UKA using computed tomography (CT). During sagittal tibial resection, we utilized the ASIS as a rotational landmark. In 47 knees that underwent postoperative CT scans after medial UKA, the tibial component position was assessed by drawing a line tangential to the lateral wall of the tibial component. Rotation of the tibial component was measured using two reference lines: a line perpendicular to the posterior cortical rim of the tibia (angle α) and Akagi's line (angle β). Instant bearing position and posterior cruciate ligament (PCL) fossa involvement were also evaluated. External rotation of the tibial component relative to each reference line was considered positive values. The mean α and β angles were 8.0° ± 6.1° (range -4.0 to 24.3) and 8.7° ± 4.8° (range 1.9-25.2), respectively. Fourteen knees (29.8 %) showed PCL fossa involvement of the tibial resection margin. One bearing showed complete 180° rotation at 2 weeks postoperatively. Due to the wide variation and inherent difficulty of identifying the ASIS during the operation, it is not recommended for guidance of sagittal tibial resection during medial UKA. In cases of inappropriate tibia component rotation, risk of PE bearing spinning and iatrogenic PCL injury should be reminded after medial UKA. IV.

  2. Finite Element Analysis of Mobile-bearing Unicompartmental Knee Arthroplasty: The Influence of Tibial Component Coronal Alignment

    PubMed Central

    Zhu, Guang-Duo; Guo, Wan-Shou; Zhang, Qi-Dong; Liu, Zhao-Hui; Cheng, Li-Ming

    2015-01-01

    Background: Controversies about the rational positioning of the tibial component in unicompartmental knee arthroplasty (UKA) still exist. Previous finite element (FE) studies were rare, and the results varied. This FE study aimed to analyze the influence of the tibial component coronal alignment on knee biomechanics in mobile-bearing UKA and find a ration range of inclination angles. Methods: A three-dimensional FE model of the intact knee was constructed from image data of one normal subject. A 1000 N compressive load was applied to the intact knee model for validating. Then a set of eleven UKA FE models was developed with the coronal inclination angles of the tibial tray ranging from 10° valgus to 10° varus. Tibial bone stresses and strains, contact pressures and load distribution in all UKA models were calculated and analyzed under the unified loading and boundary conditions. Results: Load distribution, contact pressures, and contact areas in intact knee model were validated. In UKA models, von Mises stress and compressive strain at proximal medial cortical bone increased significantly as the tibial tray was in valgus inclination >4°, which may increase the risk of residual pain. Compressive strains at tibial keel slot were above the high threshold with varus inclination >4°, which may result in greater risk of component migration. Tibial bone resection corner acted as a strain-raiser regardless of the inclination angles. Compressive strains at the resected surface slightly changed with the varying inclinations and were not supposed to induce bone resorption and component loosening. Contact pressures and load percentage in lateral compartment increased with the more varus inclination, which may lead to osteoarthritis progression. Conclusions: Static knee biomechanics after UKA can be greatly affected by tibial component coronal alignment. A range from 4° valgus to 4° varus inclination of tibial component can be recommended in mobile-bearing UKA. PMID

  3. All-polyethylene tibial components in octogenarians: survivorship, performance, and cost.

    PubMed

    van der Ven, Alexander; Scott, Richard D; Barnes, C Lowry

    2014-01-01

    The ideal recipient for an all-polyethylene tibial (APT) component continues to be controversial. Several recent randomized clinical studies have demonstrated clinical efficacy of APT when compared to metal backed tibial (MBT) components in relation to survival and clinical outcomes measures, particularly in an elderly population. In this retrospective series, 166 knees in 130 patients (age > 80 years) received an APT component. Average follow-up for the living and deceased was 5.7 and 5.2 years, respectively. There were no APT failures at the time of most recent follow-up. Knee Society function score improved from 30 to 48. Almost all respondents reported either good or excellent satisfaction with their outcome. The average cost savings of using APT instead of MBT component can be substantial. We believe octogenarian patients represent the ideal population for an APT component, that functional outcomes and satisfaction levels will be acceptable to those patients, and that the component will outlast the remaining life of the patient while also potentially providing a substantial cost savings, compared with the cost of MBT components.

  4. Contact stress analysis of the tibial component of prosthetic knee implants.

    PubMed

    McGloughlin, T M; Monaghan, J M

    1997-01-01

    The engineering problems associated with implantation into the human body of prosthetic knee implants and some of the outstanding issues facing engineering designers in this growing sector of orthopaedic medicine are described. The contact behaviour of polymeric tibial components was modelled using a stainless steel indentor in contact with an Araldite CT200 block which contained embedded strain gauges. The block was subjected to normal and sliding loads and the stresses in the block were evaluated using the strain data; the results were compared with results obtained from finite element analysis. The results are considered in the light of recent experience with non-conforming knee implants.

  5. Total Knee Arthroplasty Using Cementless Porous Tantalum Monoblock Tibial Component: A Minimum 10-Year Follow-Up.

    PubMed

    De Martino, Ivan; D'Apolito, Rocco; Sculco, Peter K; Poultsides, Lazaros A; Gasparini, Giorgio

    2016-10-01

    Cementless fixation in total knee arthroplasty (TKA) was introduced to improve the longevity of implants but has yet to be widely adopted because of reports of higher failure rates in some series. The cementless tantalum monoblock tibial component, in contrast, has shown successful short-term results, but long-term survivorship with this design is still lacking. The purpose of this study was to investigate the minimum 10-year clinical and radiographic results of the cementless tantalum monoblock tibial component in primary TKA. From March 2002 to March 2005, 33 patients (33 knees) underwent primary TKA with a cementless tantalum monoblock tibial component. All patients were followed clinically and radiographically for a minimum of 10 years (mean 11.5 years, range 10-13 years). No patients were lost to follow-up. The underlying diagnosis that led to the primary TKA was primary osteoarthritis in 31 knees and post-traumatic osteoarthritis in 2 knees. None of the components was revised. At a minimum 10-year follow-up, the survivorship with reoperation for any reason as end point was 96.9%. With tibial component revision for aseptic loosening or osteolysis as the end point survivorship was 100%. There was no radiographic evidence of tibial component loosening, subsidence, osteolysis, or migration at the time of the latest follow-up. The mean Knee Society knee scores improved from 56 points preoperatively to 93 points at the last clinical visit. The porous tantalum tibial monoblock component demonstrated excellent clinical and radiographic outcomes with no component revisions for aseptic loosening at a minimum follow-up of 10 years. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. How to assess femoral and tibial component rotation after total knee arthroplasty with computed tomography: a systematic review.

    PubMed

    De Valk, Eduard J; Noorduyn, Julia C A; Mutsaerts, Eduard L A R

    2016-11-01

    One of the most important factors leading to revision of total knee arthroplasties (TKA) is malrotation of femoral and/or tibial component. Rotation measurements performed on radiographs are limited and less reliable compared to 2D computed tomography (CT). Nowadays, 2D-CT and 3D-CT can be distinguished in measuring rotation of the TKA components. The aim of this systematic review is to determine the most reliable CT techniques in measuring rotation of the TKA components and to investigate possible cut-off points that can be used in the clinician's decision for a possible revision of the TKA. A search of PubMed, Embase, the Cochrane Central Register of Controlled Trials and Web of Science was performed up to April 2015. Final selections of 12 articles were used in this systematic review. 3D-CT, compared to 2D-CT, is more reliable and shows a high level of intra- and interobserver reliability. Femoral component rotation is measured using the component's posterior condylar line or inner pegs in relation to the epicondylar axis. Five different techniques were used to measure tibial component rotation. The posterior border of the tibial component in relationship to the geometric centre and tibial tubercle was most frequently used. This systematic review shows a strong preference for 3D-CT to determine the component's rotation following a TKA. The literature shows consensus on the reference points of the femoral component. In measurements of the tibial component, various techniques are used with similar results. No clear cut-off point for revision of malrotated TKA components can be stated because of limited evidence. III.

  7. Pressurization of bone cement under standard, flanged and custom acetabular components for total hip replacement.

    PubMed

    Beverland, D E; Kernohan, W G; Nixon, J R; Orr, J F; Watson, P

    1993-01-01

    Custom acetabular components are proposed to achieve uniform cement mantles, even in irregular acetabula presented at revision, in order to enhance fixation. One aim of developing custom components was to permit pressurization of bone cement by the components at insertion and maintain the pressure during polymerization. A model acetabulum was set up for the insertion of standard, flanged and custom components under constant force. Cement pressure was measured at the floor of the acetabulum by means of a piezoelectric diaphragm transducer. Polythene tubes were inserted in the model acetabular walls to estimate penetration of cement into cancellous bone. Insertion of the standard and flanged components caused cement pressures up to 106 kPa which decayed to less than 21 kPa as cement escaped at the rim and the components came into contact with the acetabulum. The custom component maintained a pressure of over 60 kPa during polymerization from an initial pressure of 105 kPa and examination of cement mantles on removal showed no evidence of contact. The custom component also showed enhanced penetration of cement, especially around the rim of the acetabulum. It is concluded that the custom component design achieves higher cement pressures and that better fixation will result.

  8. 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.

  9. Cementing

    SciTech Connect

    Smith, D.K.

    1989-01-01

    This book provides a reference on materials and techniques used in cementing, including pertinent new information developed since the author's original 1976 edition. It discusses basic principles, materials, and techniques of cementing, as well as field applications and limitations of procedures. The text follows the logical sequence of field cementing operations, with chapters on cements, additives, testing, job planning, and execution of primary, liner and squeeze cementing and plugging operations. It emphasizes planning for zonal isolation.

  10. 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

    2017-11-27

    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

  11. The effect of viscosity on cement penetration in total knee arthroplasty, an application of the squeeze film effect.

    PubMed

    Silverman, Edward J; Landy, David C; Massel, Dustin H; Kaimrajh, David N; Latta, Loren L; Robinson, Raymond P

    2014-10-01

    The authors present a prospective randomized blinded cadaver study designed to evaluate the engineering concept of a squeeze film effect and the effect of cement viscosity on cement penetration in total knee arthroplasty. This was done in response to an earlier clinical study demonstrating inferior tibial cement penetration using early, often liquid, phase cement. Paired cadaver tibias were implanted with the tibial component using either liquid or dough phase cement. Based on an AP fluoroscopic image, the dough phase cement penetrated deeper than liquid in all four zones. This was statistically significant in zones 1, 2 and 3. Deeper cement penetration has been shown to provide a stronger cement-bone interphase. As a result dough phase cement is recommended to obtain optimal cement penetration. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Excellent survival of all-polyethylene tibial components in a community joint registry.

    PubMed

    Gioe, Terence J; Sinner, Penny; Mehle, Susan; Ma, Wenjun; Killeen, Kathleen K

    2007-11-01

    The advantages of the monoblock design and lower cost have prompted renewed interest in the all-polyethylene tibia in total knee arthroplasty. We prospectively followed patients with all-polyethylene tibial total knee arthroplasties over a 14-year period. Since 1991, 443 total knee arthroplasties using an all-polyethylene tibia component were implanted by 12 surgeons in four hospitals associated with a community registry. One of three designs was used in over 98% of cases. The mean age of the patient population was 77 years and 78% were female. Ninety-three patients died with their prosthesis intact. Three revisions were performed on this population with mean followup of 66.3 months (range, 0-158 months). Kaplan-Meier survival analysis revealed 99.4% survival at 14.3 years with revision for any reason as the end point. With aseptic loosening or wear as the revision reason, survival is 99.7% at 14.3 years. Total knee arthroplasty with one of the three contemporary congruent all-polyethylene tibia designs used in this registry performed extremely well in this population; savings for this group (compared to those with a metal-backed component) was estimated at $729 per case. If all patients older than 75 years of age in our registry had received an all-polyethylene tibia, the estimated savings for the implant alone would have been $1.28 million. Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

  13. Creep and fatigue behavior of a novel 2-component paste-like formulation of acrylic bone cements.

    PubMed

    Köster, Ulrike; Jaeger, Raimund; Bardts, Mareike; Wahnes, Christian; Büchner, Hubert; Kühn, Klaus-Dieter; Vogt, Sebastian

    2013-06-01

    The fatigue and creep performance of two novel acrylic bone cement formulations (one bone cement without antibiotics, one with antibiotics) was compared to the performance of clinically used bone cements (Osteopal V, Palacos R, Simplex P, SmartSet GHV, Palacos R+G and CMW1 with Gentamicin). The preparation of the novel bone cement formulations involves the mixing of two paste-like substances in a static mixer integrated into the cartridge which is used to apply the bone cement. The fatigue performance of the two novel bone cement formulations is comparable to the performance of the reference bone cements. The creep compliance of the bone cements is significantly influenced by the effects of physical ageing. The model parameters of Struik's creep law are used to compare the creep behavior of different bone cements. The novel 2-component paste-like bone cement formulations are in the group of bone cements which exhibit a higher creep resistance.

  14. Effect of phase composition of calcium silicate phosphate component on properties of brushite based composite cements

    SciTech Connect

    Sopcak, T., E-mail: tsopcak@imr.saske.sk; Medvecky, L.; Giretova, M.

    2016-07-15

    The composite cement mixtures were prepared by mixing brushite (B) with, the amorphous hydrated calcium silicate phosphate (CSPH) or annealed calcium silicate phosphate (CSP composed of Si-saturated hydroxyapatite, wollastonite and silica) phases and water as liquid component. The contents of the silicate-phosphate phase in composites were 10.30 and 50 wt%. The significant effect of both the Ca/P ratio and different solubility of calcium silicate phosphate component in starting cement systems on setting time and phase composition of the final composite cements was demonstrated. The compressive strength of the set cements increased with the filler addition and the highest value (~more » 48 MPa) exhibited the 50CSP/B cement composite. The final setting times of the composite cements decreased with the CSPH addition from about 25 to 17 min in 50CSHP/B and setting time of CSP/B composites was around 30 min. The higher content of silica in cements caused the precipitation of fine hydroxyapatite particles in the form of nanoneedles or thin plates perpendicularly oriented to sample surface. The analysis of in vitro cement cytotoxicity demonstrated the strong reduction in cytotoxicity of 10CSPH/B composite with time of cultivation (a low cytotoxicity after 9 days of culture) contrary to cements with higher calcium silicate-phosphate content. These results were attributed to the different surface topography of composite substrates and possible stimulation of cell proliferation by the slow continuously release of ions from 10CSPH/B cement. - Highlights: • Ca/P ratio and solubility of calcium silicate-phosphate components affect the self-setting properties of cements. • Strong relationship between the composite in vitro cytotoxicity and surface microtopography was demonstrated. • Plate-like morphology of coarser particles allowed cells to better adhere and proliferate as compared with nanoneedles.« less

  15. Effect of phase composition of calcium silicate phosphate component on properties of brushite based composite cements

    SciTech Connect

    Sopcak, T.; Medvecky, L.; Giretova, M.; Stulajterova, R.; Durisin, J.; Girman, V.; Faberova, M.

    2016-07-15

    The composite cement mixtures were prepared by mixing brushite (B) with, the amorphous hydrated calcium silicate phosphate (CSPH) or annealed calcium silicate phosphate (CSP composed of Si-saturated hydroxyapatite, wollastonite and silica) phases and water as liquid component. The contents of the silicate-phosphate phase in composites were 10.30 and 50 wt%. The significant effect of both the Ca/P ratio and different solubility of calcium silicate phosphate component in starting cement systems on setting time and phase composition of the final composite cements was demonstrated. The compressive strength of the set cements increased with the filler addition and the highest value (~ 48 MPa) exhibited the 50CSP/B cement composite. The final setting times of the composite cements decreased with the CSPH addition from about 25 to 17 min in 50CSHP/B and setting time of CSP/B composites was around 30 min. The higher content of silica in cements caused the precipitation of fine hydroxyapatite particles in the form of nanoneedles or thin plates perpendicularly oriented to sample surface. The analysis of in vitro cement cytotoxicity demonstrated the strong reduction in cytotoxicity of 10CSPH/B composite with time of cultivation (a low cytotoxicity after 9 days of culture) contrary to cements with higher calcium silicate-phosphate content. These results were attributed to the different surface topography of composite substrates and possible stimulation of cell proliferation by the slow continuously release of ions from 10CSPH/B cement. - Highlights: • Ca/P ratio and solubility of calcium silicate-phosphate components affect the self-setting properties of cements. • Strong relationship between the composite in vitro cytotoxicity and surface microtopography was demonstrated. • Plate-like morphology of coarser particles allowed cells to better adhere and proliferate as compared with nanoneedles.

  16. Cementing

    SciTech Connect

    Smith, D.K.

    1987-01-01

    This fourth volume in the SPE Monograph Series is a 260-page reference on materials and techniques used in cementing, including pertinent new information developed since the author's original 1976 edition. Discusses basic principles, materials, and techniques of cementing, as well as field applications and limitations of procedures. Text follows the logical sequence of field cementing operations, with chapters on cements, additives, testing, job planning, and execution of primary, liner, and squeeze cementing and plugging operations. Emphasizes planning for zonal isolation. Extensive 25-page bibliography lists important papers in the field. Includes 122 tables and 242 figures.

  17. 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.

  18. 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

  19. Analysis of retrieved ultra-high-molecular-weight polyethylene tibial components from rotating-platform total knee arthroplasty.

    PubMed

    Garcia, Ryan M; Kraay, Matthew J; Messerschmitt, Patrick J; Goldberg, Victor M; Rimnac, Clare M

    2009-01-01

    Mobile-bearing total knee Arthroplasties (TKAs) were designed to increase conformity, decrease contact stresses, and decrease polyethylene damage. Our objective was to evaluate the performance of retrieved mobile-bearing TKAs with respect to wear damage of the polyethylene in a series of components obtained at revision surgery. Tibial component polyethylene superior and inferior surface damage and radiographic radiolucency analysis was conducted on 40 retrieved mobile-bearing TKAs. Higher levels of superior articulating surface damage were found to be associated with higher levels of inferior surface damage in this retrieval study. Greater levels of damage were present on both surfaces in components with greater radiographic radiolucency scores and mechanically loose components. The mobile-bearing TKA remains vulnerable to polyethylene wear damage at the superior surface and introduces an independent inferior surface also vulnerable to wear damage.

  20. 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.

  1. Mid- and long-term results of femoral component revision using the cement-in-cement technique: Average 10.8-year follow-up study.

    PubMed

    Okuzu, Yaichiro; Goto, Koji; So, Kazutaka; Kuroda, Yutaka; Matsuda, Shuichi

    2016-11-01

    Few reports are available on the long-term outcomes of femoral component revision by using the cement-in-cement technique. We report the mid- and long-term results of femoral component revision in total hip arthroplasty using the cement-in-cement technique. Between April 1996 and June 2009, 62 consecutive total hip arthroplasties with femoral component revision were performed in 57 patients by using the cement-in-cement technique. We retrospectively reviewed the cases with a follow-up period of at least five years. Three patients died, and two were lost to follow-up. Thus, 52 patients (57 hips), comprising 51 women and one man, were followed for average 10.8 years. The mean Japanese Orthopaedic Association hip score improved from 57.6 points (range, 28-95 points) preoperatively to 79.8 points (range, 52-98 points) at one year postoperatively and to 77.4 points (range, 59-96 points) at the final follow up. Three revisions of the femoral component were necessary. One of the causes for the revision was a periprosthetic infection that occurred 20 months postoperatively. Another was aseptic loosening that occurred 99 months postoperatively and required revision of the acetabular component. The well-fixed femoral component was revised using the cement-in-cement technique at time of the acetabular revision. The third case was aseptic loosening of the femoral component that occurred 84 months postoperatively. The five-, 10-, and 15-year survival rates for the femoral re-revision due to any reason were 98.4%, 94.0%, and 94.0%, respectively. Use of the cement-in-cement technique for revision total hip arthroplasty resulted in good mid- and long-term radiological and clinical outcomes. Copyright © 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

  2. [Contact allergy to metals and bone cement components in patients with intolerance of arthroplasty].

    PubMed

    Eben, R; Dietrich, K-A; Nerz, C; Schneider, S; Schuh, A; Banke, I J; Mazoochian, F; Thomas, P

    2010-07-01

    Complications in arthroplasty are mostly attributed to wear particle related loosening, infections or mechanical failure. There is no investigation in a large patient series giving data about the frequency of allergic reactions to metals or bone cement components in arthroplasty with complications. In 92 patients with cemented hip or knee arthroplasty (66 patients with complications, 26 without symptoms) patch testing and medical history were evaluated. Contact allergy rates to metals and potential bone cement components were analyzed as well as type of complaints and allergy history. Main complaints were pain (81.8%), reduced range of motion (54.5%) and local swelling (56.1%). Contact allergy to nickel was shown in 16/66 patients (24.2%), 6.1% were allergic to cobalt and 3.0% to chromium. 21/66 patients (31.8%) showed an allergic reaction to bone cement components (gentamicin 23.8%, benzoyl peroxide 10.6%, hydroquinone 4.5%). Sensitization rates in patients without symptoms were 3.8% to nickel as well as to cobalt and chromium, and 15.4% to gentamicin. Contact allergy rates to metals and potential bone cement components are higher in arthroplasty patients with complications than in the general population. Copyright (c) Georg Thieme Verlag KG Stuttgart--New York.

  3. [An evaluation of the methods used for removal of components and cement in revision hip arthroplasty].

    PubMed

    Erdemli, Bülent

    2004-01-01

    This study was designed to evaluate the methods that we used for removal of components and cement in revision hip arthroplasty (RHA). Thirty-seven patients (mean age 65.6 years; range 18 to 78 years) who underwent RHA were retrospectively evaluated. Arthroplasty had been cementless, hybrid, cemented, and partial in 13, 16, 5, and 3 hips, respectively. Revision included only acetabular cup in four patients, femoral component in three, and all components in the remaining patients. Of the acetabular cups revised, five were cemented, 28 were cementless (10 expanded, 18 porous-coated); of the femoral components, 22 were cemented and 11 were cementless. The mean time to revision was 7.3 years (range 1.5 to 13 years). Extended proximal femoral osteotomy (EPFO) was performed in 28 hips (84.9%), of which 10 hips (35.7%) required the use of high speed cutting heads. All the patients were evaluated before and after revision according to the criteria of Merle d'Aubigne and Postel which were modified by Charnley. The mean follow-up period was 36.3 months (range 2 to 48 months). There were no difficulties in the removal of cemented acetabular cups. Expanded cementless cups were readily removed by bending their expanded leaves. However, high speed cutting heads were used to resolve the bone-cup integration in eight porous-coated cups (44.4%); of these, two cups (25%) even required the use of high speed metal cutting heads to split several parts apart. In one patient, a spiral fracture occurred extending to the distal end of EPFO. On final follow-ups, the results were evaluated as perfect or good in 92% of the hips. The removal of components and cement during RHA may require the use of more complex methods and device in addition to standard ones.

  4. The use of a modular titanium baseplate with a press-fit keel implanted with a surface cementing technique for primary total knee arthroplasty.

    PubMed

    Pelt, Christopher E; Erickson, Jill; Christensen, Bryt A; Widmer, Benjamin; Severson, Erik P; Evans, David; Peters, Christopher L

    2014-01-01

    Little data exists regarding outcomes following TKA performed with surface-cementation for the fixation of modular tibial baseplates with press-fit keels. Thus, we retrospectively reviewed the clinical and radiographic outcomes of 439 consecutive primary TKAs performed with surface cemented tibial components. There were 290 female patients and 149 male patients with average age of 62 years (range 30-84). Two tibial components were revised for aseptic loosening (0.5%) and four tibial components (0.9%) were removed to improve instability (n = 2) or malalignment (n = 2). Complications included 13 deep infections treated with 2-stage revision (12) and fusion (1). These results support the surface cement technique with a modular grit-blasted titanium surface and cruciform stem during primary TKA.

  5. 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.

  6. 21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/metal semi-constrained, with a... Devices § 888.3320 Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented acetabular...

  7. 21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/metal semi-constrained, with a... Devices § 888.3320 Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented acetabular...

  8. 21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented acetabular... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. 888.3320 Section 888.3320 Food and Drugs FOOD AND DRUG...

  9. 21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented acetabular... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. 888.3320 Section 888.3320 Food and Drugs FOOD AND DRUG...

  10. 21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented acetabular... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis. 888.3320 Section 888.3320 Food and Drugs FOOD AND DRUG...

  11. Rapid polyethylene failure of unicondylar tibial components sterilized with gamma irradiation in air and implanted after a long shelf life.

    PubMed

    McGovern, Thomas F; Ammeen, Deborah J; Collier, John P; Currier, Barbara H; Engh, Gerard A

    2002-06-01

    The mechanical toughness of polyethylene that has been sterilized by gamma irradiation in air decreases after a long shelf life. The purpose of the present study is to report the high failure rate after unicondylar knee replacements performed with polyethylene bearings that had been sterilized with gamma irradiation in air and implanted after a shelf life of < or = 4.4 years. Between December 1997 and January 2000, seventy-five unicondylar knee replacements were performed in sixty-two patients. All patients were followed both clinically and radiographically. A revision operation was offered when the patient had pain, swelling, and radiographic evidence of rapid polyethylene wear. The effect of aging of the polyethylene during storage was evaluated by dividing the knees into three groups on the basis of shelf life and comparing them with regard to the rate of revision and the observed wear of the polyethylene. Four retrieved components were examined for the presence of oxidation. At a mean of eighteen months after the arthroplasty, thirty knees had been revised and seven were scheduled for revision. The rate of polyethylene wear increased as the shelf life increased. There was a significant inverse linear correlation between the shelf life of the polyethylene and the time to revision (p < 0.01, r (2) = 0.64). All retrieved components had greater-than-expected wear with pitting and delamination of the surface. Seven components had fractured, and ten had both fractured and fragmented. Analysis of four components confirmed severe oxidation of the polyethylene. The present study demonstrated early, severe wear of tibial polyethylene bearings that had been sterilized by gamma irradiation in air and stored for < or = 4.4 years. This risk can be minimized by ensuring that implants have not been sterilized with gamma irradiation in air and stored for several years.

  12. Tibial fractures.

    PubMed

    Seaman, Jeffrey A; Simpson, Amelia M

    2004-08-01

    Tibial fractures are common in small animal practice. As with other appendicular fractures, the patient's age, fracture location, and fracture type must be considered thoroughly. While methods for tibial fracture repair are similar to those used for appendicular fractures elsewhere, there are some unique considerations, both anatomically and functionally, that must be contemplated before repair. The following article will review the incidence of tibial fractures, tibial fracture types, and options for tibial fracture management and treatment. The use of external fixators, orthopedic bone plates, open reduction with internal fixation (ORIF), and external coaptation will be discussed. An emphasis will be placed on the most common types of tibial fractures, as well as those best suited for repair by general practitioners of veterinary medicine. Three case based examples will follow the overview.

  13. [Polyethylene replacement by cementing a new component over the osseointegrated metal-back].

    PubMed

    Espinosa-Ruiz, A; Zorrilla-Ribot, P; Salido-Valle, J A

    2015-01-01

    In uncemented revision total hip replacement due to polyethylene wear, the metal cup needs to be maintained when its stability is checked during surgery, only replacing the polyethylene that is cemented if anchoring is not possible. The aim of the present study was to evaluate the medium-term clinical and radiological results of a polyethylene liner cemented into an osseointegrated acetabular shell component. A retrospective analysis was performed on 15 patients in whom the surgical indication was polyethylene wear, with a mean follow-up of 6.1 years (range 3.5-9.7 years). The Harris Hip Score was used to assess the clinical results before surgery and at the end of follow-up. Anteroposterior and axial X-rays of the hip were taken to rule out complications. The mean Harris Hip Score improved, increasing from 64.7 points before the surgery to 80.3 at the end of follow-up. The osteolytic lesions disappeared, or at least the size did not increase, in the follow-up X-rays. One patient (6.7%) suffered 2 dislocation episodes that were treated without the need for surgery. Another patient presented with aseptic loosening of the femoral stem that required a replacement. Cementing the polyethylene liner, when anchoring is not possible, in an uncemented osseointegrated metal shell is a technique that offers good results in the medium term, and which may minimise the complications that may occur with the replacement of the shell component, without compromising its stability. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.

  14. Minimizing Stress Shielding and Cement Damage in Cemented Femoral Component of a Hip Prosthesis through Computational Design Optimization

    PubMed Central

    Fischer, Justin; Yadav, Rohan

    2017-01-01

    The average life expectancy of many people undergoing total hip replacement (THR) exceeds twenty-five years and the demand for implants that increase the load-bearing capability of the bone without affecting the short- or long-term stability of the prosthesis is high. Mechanical failure owing to cement damage and stress shielding of the bone are the main factors affecting the long-term survival of cemented hip prostheses and implant design must realistically adjust to balance between these two conflicting effects. In the following analysis we introduce a novel methodology to achieve this objective, the numerical technique combines automatic and realistic modeling of the implant and embedding medium, and finite element analysis to assess the levels of stress shielding and cement damage and, finally, global optimization, using orthogonal arrays and probabilistic restarts, were used. Applications to implants, fabricated using a homogeneous material and a functionally graded material, were presented. PMID:28348892

  15. A randomised study of peri-prosthetic bone density after cemented versus trabecular fixation of a polyethylene acetabular component.

    PubMed

    Periasamy, K; Watson, W S; Mohammed, A; Murray, H; Walker, B; Patil, S; Meek, R M D

    2011-08-01

    The ideal acetabular component is characterised by reliable, long-term fixation with physiological loading of bone and a low rate of wear. Trabecular metal is a porous construct of tantalum which promotes bony ingrowth, has a modulus of elasticity similar to that of cancellous bone, and should be an excellent material for fixation. Between 2004 and 2006, 55 patients were randomised to receive either a cemented polyethylene or a monobloc trabecular metal acetabular component with a polyethylene articular surface. We measured the peri-prosthetic bone density around the acetabular components for up to two years using dual-energy x-ray absorptiometry. We found evidence that the cemented acetabular component loaded the acetabular bone centromedially whereas the trabecular metal monobloc loaded the lateral rim and behaved like a hemispherical rigid metal component with regard to loading of the acetabular bone. We suspect that this was due to the peripheral titanium rim used for the mechanism of insertion.

  16. Assessing Tibial Tray Rotation in TKA: A Cadaveric Study.

    PubMed

    Hakki, Sam; El-Othmani, Mouhanad M; Gabriel, Christian; Mihalko, William M; Saleh, Khaled J

    2016-05-01

    Tibial anatomical landmarks for transverse plane rotation of the tibial tray have not been validated. The current authors propose aligning the tibial tray with both the anterior tibial center point of rotation (ATCPR) and the femoral trochlear groove (FTG) to establish the ideal tibial tray rotation in total knee arthroplasty (TKA). When the tibial tray centerline was aligned with ATCPR and FTG lines, the mean range of motion (ROM) was 144.3° (preoperatively 145°) and tibial rotation range was 22.8 mm (preoperatively, 24.9 mm). When the tibial component was rotated 5 mm medially to the ATCPR, the knee ROM decreased in flexion with patellar subluxation, while it decreased in extension when rotated 5 mm laterally. This method identifies the ideal tibial tray rotation in TKA, at which maximal range of tibial rotation and knee ROM are achieved without obvious overriding of components. [Orthopedics, 2016; 39(3):S67-S71.]. Copyright 2016, SLACK Incorporated.

  17. Adhesive strength of total knee endoprostheses to bone cement - analysis of metallic and ceramic femoral components under worst-case conditions.

    PubMed

    Bergschmidt, Philipp; Dammer, Rebecca; Zietz, Carmen; Finze, Susanne; Mittelmeier, Wolfram; Bader, Rainer

    2016-06-01

    Evaluation of the adhesive strength of femoral components to the bone cement is a relevant parameter for predicting implant safety. In the present experimental study, three types of cemented femoral components (metallic, ceramic and silica/silane-layered ceramic) of the bicondylar Multigen Plus knee system, implanted on composite femora were analysed. A pull-off test with the femoral components was performed after different load and several cementing conditions (four groups and n=3 components of each metallic, ceramic and silica/silane-layered ceramic in each group). Pull-off forces were comparable for the metallic and the silica/silane-layered ceramic femoral components (mean 4769 N and 4298 N) under standard test condition, whereas uncoated ceramic femoral components showed reduced pull-off forces (mean 2322 N). Loading under worst-case conditions led to decreased adhesive strength by loosening of the interface implant and bone cement using uncoated metallic and ceramic femoral components, respectively. Silica/silane-coated ceramic components were stably fixed even under worst-case conditions. Loading under high flexion angles can induce interfacial tensile stress, which could promote early implant loosening. In conclusion, a silica/silane-coating layer on the femoral component increased their adhesive strength to bone cement. Thicker cement mantles (>2 mm) reduce adhesive strength of the femoral component and can increase the risk of cement break-off.

  18. Medium-term follow-up of 92 femoral component revisions using a third-generation cementing technique

    PubMed Central

    Te Stroet, Martijn A J; Rijnen, Wim H C; Gardeniers, Jean W M; Van Kampen, Albert; Schreurs, B Willem

    2016-01-01

    Background and purpose — Very little has been published on the outcome of femoral cemented revisions using a third-generation cementing technique. We report the medium-term outcome of a consecutive series of patients treated in this way. Patients and methods — This study included 92 consecutive cemented femoral revisions performed in our department with a third-generation cementing technique and without instrumented bone impaction grafting between 1996 and 2007. The average age of the patients at revision was 66 (25–92) years. None of the patients were lost to follow-up. At review in December 2013, 55 patients were still alive and had a non-re-revised femoral revision component in situ after a mean follow-up of 11 (5–17) years. Results — The mean preoperative Harris hip score was 50, and improved to 73 at final follow-up. 2 patients died shortly after the revision surgery. 1 stem was re-revised for aseptic loosening; this was also the only case with radiolucent lines in all 7 Gruen zones. A femoral reoperation was performed in 19 hips during follow-up, and in 14 of these 19 reoperations the femoral component was re-revised. Survivorship at 10 years, with femoral re-revision for any reason as the endpoint, was 86% (95% CI: 77–92). However, excluding 8 patients with reinfections after septic index revisions and 1 with hematogenous spread of infection from the survival analysis, the adjusted survival for re-revision for any reason at 10 years was 92% (95% CI: 83–96). With re-revision for aseptic loosening as endpoint, the survival at 10 years was 99% (CI: 90–100). Interpretation — Femoral component revision with a third-generation cemented stem results in acceptable survival after medium-term follow-up. We recommend the use of this technique in femoral revisions with limited loss of bone stock. PMID:26569495

  19. Optimisation of a two-liquid component pre-filled acrylic bone cement system: a design of experiments approach to optimise cement final properties.

    PubMed

    Clements, James; Walker, Gavin; Pentlavalli, Sreekanth; Dunne, Nicholas

    2014-10-01

    The initial composition of acrylic bone cement along with the mixing and delivery technique used can influence its final properties and therefore its clinical success in vivo. The polymerisation of acrylic bone cement is complex with a number of processes happening simultaneously. Acrylic bone cement mixing and delivery systems have undergone several design changes in their advancement, although the cement constituents themselves have remained unchanged since they were first used. This study was conducted to determine the factors that had the greatest effect on the final properties of acrylic bone cement using a pre-filled bone cement mixing and delivery system. A design of experiments (DoE) approach was used to determine the impact of the factors associated with this mixing and delivery method on the final properties of the cement produced. The DoE illustrated that all factors present within this study had a significant impact on the final properties of the cement. An optimum cement composition was hypothesised and tested. This optimum recipe produced cement with final mechanical and thermal properties within the clinical guidelines and stated by ISO 5833 (International Standard Organisation (ISO), International standard 5833: implants for surgery-acrylic resin cements, 2002), however the low setting times observed would not be clinically viable and could result in complications during the surgical technique. As a result further development would be required to improve the setting time of the cement in order for it to be deemed suitable for use in total joint replacement surgery.

  20. The effect of high tibial osteotomy on the posterior tibial slope.

    PubMed

    Dragosloveanu, Serban; Cristea, Stefan; Dragosloveanu, Calin

    2014-06-01

    High tibial osteotomy remains a useful procedure for delaying total knee arthroplasty for young patients with unicompartimental medial osteoarthritis of the knee. The tibial posterior slope is essential for both ligament function and knee kinematics. Even though many articles were published in the literature, the long term influence of open wedge high tibial osteotomy on the posterior slope of the tibial plateau remains unknown. We assessed the relationship among the degree of correction, the surgical technique, the postoperative modification of tibial slope, knee flexion and Knee score at the two years. We used for evaluation a calibrated x-rays with correction factor. All the measures were done with Cedara I-View 6.3.2 application. All 47 patients were operated in our hospital between 2008-2011, with the same technique, open wedge high tibial osteotomy with an acrylic cement wedge. All patients postponed weight bearing for 6 weeks. We found that there is no statistical significance (p=0.2) between the preoperative varus and the after surgery tibial slope, but the resulting posterior inclination after surgery influences the tibial posterior slope at 2 years (p<=0.005).The degree of correction has a strong influence over the increase or decrease of tibial posterior slope(p<0.005). An increase in tibial slope increases the knee flexion by 1.45° for every degree of inclination (p<0.05). Functional results are not influenced by small modifications in tibial inclination (p>0.05). From this findings we may conclude that the most important factors that changes the posterior inclination of the tibia surface are the height of the cement wedge and the surgical technique, by placing the acrylic cement wedge more anteriorly. We have found that the vast majority of our high tibial osteotomies are in fact "flexion" osteotomies. At the 2 years control we have found a slight increase in tibial slope angle (average 1.77°) and knee flexion (average 2.56°) with no functional

  1. Radiographic comparison of finned, cementless central pegged glenoid component and conventional cemented pegged glenoid component in total shoulder arthroplasty: a prospective randomized study.

    PubMed

    Kilian, Christopher M; Morris, Brent J; Sochacki, Kyle R; Gombera, Mufaddal M; Haigler, Richard E; O'Connor, Daniel P; Edwards, T Bradley

    2017-12-13

    Radiographic lucency of the glenoid component remains a problem after cement fixation in primary total shoulder arthroplasty. Glenoid component design likely contributes to rates of glenoid lucency. The purpose of this study was to prospectively compare radiographic lucency between a finned, cementless central pegged glenoid component (CL component) and a conventional cemented pegged glenoid component (P component) on immediate postoperative and minimum 2-year follow-up radiographs. Fifty-four patients undergoing total shoulder arthroplasty were prospectively randomized to receive an all-polyethylene CL component or a conventional all-polyethylene P component. Three raters graded glenoid lucency and bone interdigitation on immediate postoperative and latest follow-up radiographs. Patients who had undergone revision surgery or had died before evaluation were excluded. Minimum 2-year follow-up was required for inclusion of radiographic evaluation. Fifty patients met inclusion criteria; 42 patients (84%; 20 CL and 22 P) were available for follow-up with the original glenoid implant in place. The mean follow-up duration was 35 months (24-64 months). There were no significant differences in glenoid radiolucency between CL (1/20 [5%]) and P (2/22 [9%]) components at last follow-up (P = .999). Five patients (25%) in the CL group had bone interdigitation. No instances of aseptic glenoid loosening occurred. There were no significant differences in the rate of glenoid lucency between the 2 groups at immediate or an average 35-month follow-up. Both techniques appear to be viable options for initial glenoid component fixation, with CL components allowing possible osseointegration, imparting potential long-term stability. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  2. Case series report: Early cement-implant interface fixation failure in total knee replacement.

    PubMed

    Hazelwood, Kyle J; O'Rourke, Michael; Stamos, Van P; McMillan, Robert D; Beigler, David; Robb, William J

    2015-10-01

    Early failure in cemented total knee replacement (TKR) due to aseptic loosening is uncommon. A small number of early failures requiring revision were observed at one hospital due to observed cement-implant fixation failure. The purpose of this case series is to report and identify possible causes for these early failures. Between May 2005 and December 2010, 3048 primary TKRs were performed over a five-year period of time by six surgeons. Two total knee systems were used during this period of time. Nine early failures were observed in eight patients. High viscosity cement (HVC) was used in all these cases. Aseptic loosening of the tibial component was observed in all nine early total knee failures. The high viscosity bone cement was noted to be non-adherent to the tibial trays at the time of revision surgery. HVC was used in all these cases. Properties of HVC may contribute to make it more susceptible to early failure in a small number of TKRs. HVC in total hip replacement (THR) has been associated with cement micro-fractures, cement debris generation and early implant failure. The mechanical properties of HVC may similarly contribute to early failure at the cement-implant interface in a small percentage TKRs. Published by Elsevier B.V.

  3. Prediction of fatigue failure of a total knee replacement tibial plateau using finite element analysis.

    PubMed

    Paganelli, J V; Skinner, H B; Mote, C D

    1988-08-01

    Recent reports of total knee prosthesis fractures have raised concerns over the long-term structural integrity of metal-backed tibial components. Both the development of a fibrous tissue membrane under the tibial plateau of a total knee prosthesis and loading conditions may seriously alter the fatigue life of the metal tibial tray. The effects of the cement and fibrous tissue at the bone-prosthesis interface were studied. Using the method of three-dimensional finite element analysis, peak loads of normal gait were simulated at several locations on the plateau of a generic, single-stemmed, porous-coated, CoCrMo tibial component model, providing information on the effect of abnormal loading patterns. According to the analysis, stresses below the material endurance limit are predicted throughout the prosthesis prior to the development of the fibrous membrane. However, stresses exceeding the yield strength of the material are predicted in a prosthesis that is supported by a fully developed 1 mm membrane, meaning that it has a markedly increased risk of low-cycle fatigue failure. Lateral displacement of the loading is detrimental to prosthesis life because maximum stress increases 100% while posterior displacement of the loading increases maximum stress by only 30%. Anterior loading creates stresses similar to those created by central loading. Because of their susceptibility to low-cycle fatigue failure, simple, single-stemmed prostheses are not recommended in cases of questionable bone stock unless modified. Several design alternatives are proposed.

  4. 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

    2017-09-07

    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

  5. [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.

  6. A literature review of mixed waste components: Sensitivities and effects upon solidification/stabilization in cement-based matrices

    SciTech Connect

    Mattus, C.H.; Gilliam, T.M.

    1994-03-01

    The US DOE Oak Ridge Field Office has signed a Federal Facility Compliance Agreement (FFCA) regarding Oak Ridge Reservation (ORR) mixed wastes subject to the land disposal restriction (LDR) provisions of the Resource conservation and Recovery Act. The LDR FFCA establishes an aggressive schedule for conducting treatability studies and developing treatment methods for those ORR mixed (radioactive and hazardous) wastes listed in Appendix B to the Agreement. A development, demonstration, testing, and evaluation program has been initiated to provide those efforts necessary to identify treatment methods for all of the wastes that meet Appendix B criteria. The program has assembled project teams to address treatment development needs in a variety of areas, including that of final waste forms (i.e., stabilization/solidification processes). A literature research has been performed, with the objective of determining waste characterization needs to support cement-based waste-form development. The goal was to determine which waste species are problematic in terms of consistent production of an acceptable cement-based waste form and at what concentrations these species become intolerable. The report discusses the following: hydration mechanisms of Portland cement; mechanisms of retardation and acceleration of cement set-factors affecting the durability of waste forms; regulatory limits as they apply to mixed wastes; review of inorganic species that interfere with the development of cement-based waste forms; review of radioactive species that can be immobilized in cement-based waste forms; and review of organic species that may interfere with various waste-form properties.

  7. No differences in outcomes between cemented and uncemented acetabular components after 12-14 years: results from a randomized controlled trial comparing Duraloc with Charnley cups.

    PubMed

    Bjørgul, Kristian; Novicoff, Wendy M; Andersen, S T; Brevig, K; Thu, F; Wiig, M; Ahlund, O

    2010-03-01

    Even though there are multiple studies documenting the outcome of the Charnley low-friction arthroplasty as well as abundant studies on uncemented arthroplasties, there is a dearth of comparative studies of the uncemented acetabular component and a cemented component. In this study we aimed to document the long-term clinical and radiographic outcome as well as component survival in a randomized controlled trial. Two hundred fifteen patients (240 hips) were randomly allocated to receive a cemented Charnley cup or uncemented Duraloc 1200 cup. All patients received cemented Charnley stems and were evaluated clinically and radiographically after 6 months, and 2, 5, and 10 years. Harris Hip Scores improved from 48.3 [95% confidence interval (CI) 45.0-51.6] to 90.2 [95% CI 87.9-92.6] in the Charnley group and from 49.3 [95% CI 86.9-91.3] in the Duraloc group at 6 months. After 10 years, the Charnley group's Harris Hip Score was 89.8 [95% confidence interval (CI) 87.0-92.6], and the Duraloc group's score was 87.3 (95% CI 84.1-90.6). In the radiographic analysis after 10 years, there was no statistical difference in the prevalence of radiographic signs of loosening. Nine cups were revised in the Charnley group, and five cups were removed in the Duraloc group. The difference was not statistically significant. There was no statistical difference between the cups when aseptic loosening was the end-point, nor in survival analyses. There is no statistically significant difference in clinical or radiological outcome between the Charnley cup and the Duraloc after 10 years, and no difference in implant survival after 12-14 years. The uncemented Duraloc cup is as good as the cemented Charnley cup after 10 years.

  8. Simultaneous cemented and cementless total knee replacement in the same patients: a prospective comparison of long-term outcomes using an identical design of NexGen prosthesis.

    PubMed

    Park, J-W; Kim, Y-H

    2011-11-01

    The purpose of this prospective, randomised study was to evaluate the clinical and radiological results comparing the identical cemented or cementless NexGen total knee prostheses implanted bilaterally in the same patient. Sequential simultaneous bilateral total knee replacements were performed in 50 patients (100 knees). There were 39 women and 11 men with a mean age of 58.4 years (51 to 67) who received a cemented prosthesis in one knee and a cementless prosthesis in the other. The mean follow-up was 13.6 years (13 to 14). At final review, the mean Knee Society scores (96.2 (82 to 100) versus 97.7 (90 to 100)), the mean Western Ontario and McMaster Universities osteoarthritis index (34.5 (4 to 59) versus 35.6 (5 to 51)), the mean ranges of knee movement (124° (100° to 140°) versus 128° (110° to 140°)), mean patient satisfaction (8.1 (SD 1.9) versus 8.3 (SD 1.7)), and radiological results were similar in both groups. The rate of survival of the femoral components was 100% in both groups at 14 years. The rate of survival of the cemented tibial component was 100% and 98% in the cementless tibial component. No osteolysis was identified in either group. Our data have shown no advantage of cementless over cemented components in total knee replacement.

  9. Early periprosthetic bone remodelling around cemented and uncemented custom-made femoral components and their uncemented acetabular cups.

    PubMed

    Mulier, M; Jaecques, S V N; Raaijmaakers, M; Nijs, J; Van der Perre, G; Jonkers, I

    2011-07-01

    Periprosthetic bone remodelling after total hip replacement may contribute to aseptic loosening of the prosthesis. The selection between cemented and uncemented fixation of the stem is mainly determined by patient's age, general constitution and CT scan-estimated bone quality; intra-operative observation may ultimately influence the choice of the fixation method. The influence of cemented versus uncemented stem fixation on periprosthetic bone remodelling around the uncemented cup has, to our knowledge, never been studied until now. A total of 75 patients received intra-operatively manufactured stem prostheses and a standard hydroxy apatite-coated pinnacle cup. The pre-operative CT scans provides guidance for the bone quality and hence the type of stem fixation: cemented or uncemented. The influence of either type of stem fixation on periprosthetic bone remodelling around the cup and the stem was measured by bone mineral density at 6 weeks, and 3, 6 and 12 months after surgery. Early changes in bone mineral density were noted. The type of stem fixation had an influence on the bone remodelling of the femur and also of the pelvis. The caudal part of the acetabulum was subject to a greater loss in BMD at 12 months in the group with cemented stem fixation. Changes at 12 months correlated with the changes measured at any time point. The selection of the stem implant and its type of fixation in the femoral cavity (cemented or uncemented fixation) seems to have an impact on the bone mineral density of the acetabulum. Long-term clinical follow-up is required to draw conclusions regarding the influence on prosthesis survival.

  10. Abyssal seep site cementation

    SciTech Connect

    Neumann, A.C.; Paull, C.K.; Commeau, R.

    1988-01-01

    The deepest submarine cements known so far occur along the 3,300-m deep base of the Florida escarpment and are associated with methane-bearing brine seeps, which emanate there. These deep Holocene carbonates, which occur as surficial and buried crusts, burrow fillings, and friable horizons, were sampled via ALVIN. The carbonates form irregular halos extending up to 20 m from seeps colonized by chemosynthetic fauna. Mussels, gastropods, and clams, the carbonate components of the community, produce a shell hash that is locally cemented by coarsely crystalline low-Mg calcite. Halos of palisade calcite are reminiscent of ancient examples of marine cements. Also presentmore » are carbonate hemipelagics cemented by micrite into crusts and burrow fillings. The degree of cementation varies from pervasive to light. Slabs of cemented crust up to 30 cm thick contrast with typical shallow crusts and exhibit irregular tops and smooth bottoms indicating different chemical gradients and pathways.« less

  11. A pilot trial comparing the tear-out behavior in screw-sockets and cemented polyethylene acetabular components - a cadaveric study.

    PubMed

    Möbius, R; Schleifenbaum, S; Grunert, R; Löffler, S; Werner, M; Prietzel, T; Hammer, N

    2016-10-01

    The removal of well-fixed acetabular components following THA (total hip arthroplasty) is a difficult operation and could be accompanied by the loss of acetabular bone stock. The optimal method for fixation is still under debate. The aim of this pilot study was to compare the tear-out resistance and failure behavior between osseo-integrated and non-integrated screw cups. Furthermore, we examined whether there are differences in the properties mentioned between screw sockets and cemented polyethylene cups. Tear-out resistance and related mechanical work required for the tear-out of osseo-integrated screw sockets are higher than in non-integrated screw sockets. Ten human coxal bones from six cadavers with osseo-integrated screw sockets (n=4), non-integrated (implanted post-mortem, n=3) screw sockets and cemented polyethylene cups (n=3) were used for tear-out testing. The parameters axial failure load and mechanical work for tear-out were introduced as measures for determining the stability of acetabular components following THA. The osseo-integrated screw sockets yielded slightly higher tear-out resistance (1.61±0.26kN) and related mechanical work compared to the non-integrated screw sockets (1.23±0.39kN, P=0.4). The cemented polyethylene cups yielded the lowest tear-out resistance with a failure load of 1.18±0.24kN. Compared to the screw cups implanted while alive, they also differ on a non-significant level (P=0.1). Osseous failure patterns differed especially for the screw sockets compared to the cemented polyethylene cups. Osseo-integration did not greatly influence the tear-out stability in cementless screw sockets following axial loading. Furthermore, the strength of the bone-implant-interface of cementless screw sockets appears to be similar to cemented polyethylene cups. However, given the high failure load, high mechanical load and because of the related bone failure patterns, removal should not be performed by means of tear-out but rather by osteotomes

  12. Positive effect of removal of subchondral bone plate for cemented acetabular component fixation in total hip arthroplasty: a randomised RSA study with ten-year follow-up.

    PubMed

    Flivik, G; Kristiansson, I; Ryd, L

    2015-01-01

    We hypothesised that the removal of the subchondral bone plate (SCBP) for cemented acetabular component fixation in total hip arthroplasty (THA) offers advantages over retention by improving the cement-bone interface, without jeopardising implant stability. We have previously published two-year follow-up data of a randomised controlled trial (RCT), in which 50 patients with primary osteoarthritis were randomised to either retention or removal of the SCBP. The mean age of the retention group (n = 25, 13 males) was 70.0 years (sd 6.8). The mean age in the removal group (n = 25, 16 males) was 70.3 years (sd 7.9). Now we have followed up the patients at six (retention group, n = 21; removal group, n = 20) and ten years (retention group: n = 17, removal group: n = 18), administering clinical outcome questionnaires and radiostereometric analysis (RSA), and determining the presence of radiolucent lines (RLLs) on conventional radiographs. RSA demonstrated similar translation and rotation patterns up to six years. Between six and ten years, proximal acetabular component migration and changes of inclination were larger in the retention group, although the mean differences did not reach statistical significance. Differences in migration were driven by two patients in the SCBP retention group with extensive migration versus none in the SCBP removal group. The significant difference (p < 0.001) in the development of radiolucent lines in the retention group, previously observed at two years, increased even further during the course of follow-up (p < 0.001). While recognising SCBP removal is a more demanding technique, we conclude that, wherever possible, the SCBP should be removed to improve the cement-bone interface in order to maximise acetabular component stability and longevity. ©2015 The British Editorial Society of Bone & Joint Surgery.

  13. Detection and Analysis of the Magnetic Field Component of Electromagnetic Radiation Emission from Macroscopic Fracturing of Cement-Bound Granular Material

    NASA Astrophysics Data System (ADS)

    Ceralde, Paul Ivan; Maquiling, Joel Tiu

    This study aims to detect and measure the magnetic field component of the Electromagnetic Radiation (EMR) emitted by quasi-brittle materials that undergo macroscopic fracturing. Cement-Bound Granular Materials (CBGM) were prepared by mixing cement, sand and gravel in a beam mold. Additional aggregates in the form of saw dust were added to produce variable CBGM samples. A concrete beam holder was designed and fabricated such that induced cracks from impact loading would form at the center of the beam. Six Vernier software magnetic field sensors were used to detect the magnetic field (MF) component of the EMR emission. The magnetic field sensors were set at a low amplification range (+/-6.4x10-3 T) setting with 0.0002 mT precision at 20-50 Hz. Sensor locations and orientations were specified and fixed throughout the experiment. The impact loading process was repeated until concrete failure. The time of drop was determined through the occurrence of peak sound levels (dB) induced by the collision noise using a sound level meter at fast time weighting. Magnetic field fluctuations manifesting near the occurrence of sound level impulses were recorded. Peak magnetic field values within +/-200ms from the recorded time of impact were considered to be originating from the concrete fracture.

  14. The effect of bone cement particles on the friction of polyethylene and polyurethane knee bearings

    NASA Astrophysics Data System (ADS)

    Ash, H. E.; Scholes, S. C.; Unsworth, A.; Jones, E.

    2004-08-01

    Compliant layer knee joints have been considered for use in an attempt to increase the serviceable life of artificial joints. If designed correctly, these joints should operate within the full-fluid film lubrication regime. However, adverse tribological conditions, such as the presence of bone and bone cement particles, may breach the fluid film and cause surface wear. The frictional behaviour of both polyurethane (PU) and conventional polyethylene (PE) tibial components against a metallic femoral component was therefore assessed when bone cement particles were introduced into the lubricant. The bone cement particles caused a large increase in the frictional torque of both the PE and PU bearings; however, the friction produced by the PU bearings was still considerably lower than that produced by the PE bearings. The volume of bone cement particles between each of the bearings and the resultant frictional torque both decreased over time. This occurred more quickly with the PE bearings but greater damage was caused to the surface of the PE bearings than the PU components.

  15. Tibial osteotomy - slideshow

    MedlinePlus

    ... GO GO About MedlinePlus Site Map FAQs Customer Support Health Topics Drugs & Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Tibial osteotomy - series—Normal anatomy URL of this page: //medlineplus.gov/ency/presentations/ ...

  16. Usefulness of long tibial axis to measure medial tibial slope for opening wedge high tibial osteotomy.

    PubMed

    Akamatsu, Y; Sotozawa, M; Kobayashi, H; Kusayama, Y; Kumagai, K; Saito, T

    2016-11-01

    To assess which tibial slope measurements on knee, whole leg radiographs and three-dimensional reconstructed computed tomography (CT) were useful in clinical practice before and after opening wedge high tibial osteotomy. Medial and lateral tibial slopes on knee, whole leg radiographs and three-dimensional reconstructed CT were measured in 50 patients with knee osteoarthritis. To investigate the intraobserver reproducibility and interobserver reliability for each medial and lateral tibial slope on knee, whole leg radiographs and CT, the measurements were repeated twice by two observers. The statistical differences between the medial and lateral tibial slopes obtained by the three methods, and the differences and correlation coefficients for the medial and lateral tibial slopes between knee or whole leg radiographs and CT were calculated. The reproducibility and reliability of medial and lateral tibial slopes on CT were superior to those on whole leg or knee radiographs. The medial and lateral tibial slopes on whole leg radiographs had better reproducibility and reliability than those on knee radiographs. The mean medial tibial slopes on knee, whole leg radiographs and CT were 9.3 ± 3.4°, 12.3 ± 4.3° and 11.0 ± 3.9°, respectively. The mean lateral tibial slopes were 7.9 ± 3.1°, 9.6 ± 3.6° and 9.3 ± 2.9°, respectively. The medial tibial slopes on knee, whole leg radiographs and CT were significantly higher than the lateral tibial slopes (p < 0.01 for all). Tibial slope measurements using CT required time and specialized software. Therefore, measurements of the medial tibial slope using the long tibial axis on whole leg radiographs were more reproducible and reliable and could be an alternative to CT in clinical practice. III.

  17. The influence of posterior tibial slope changes on joint gap and range of motion in unicompartmental knee arthroplasty.

    PubMed

    Takayama, Koji; Matsumoto, Tomoyuki; Muratsu, Hirotsugu; Ishida, Kazunari; Araki, Daisuke; Matsushita, Takehiko; Kuroda, Ryosuke; Kurosaka, Masahiro

    2016-06-01

    The effect of posterior slope on joint gap in unicompartmental knee arthroplasty (UKA) has yet to be quantified. The purpose of this study was to quantify the effect of the tibial slope on the joint component gap and postoperative range of motion in UKA. Forty consecutive patients were prospectively enrolled. The correlation between the tibial slope changes and the component gap, the component gap difference between flexion angles, the postoperative extension or flexion angles was examined. The correlation of joint looseness with tibial slope changes and postoperative extension angle was also examined. Increased tibial slope positively correlated with the differences between the component gap at 90° and 10°, 120° and 10°, or 135° and 10° knee flexion angle. Although tibial slope change did not affect postoperative flexion angle, increased tibial slope reduced postoperative extension angle. Moreover, increased tibial slope resulted in decreased joint looseness during 10° of knee flexion and decreased joint looseness during 10° of knee flexion resulted in reduced postoperative extension angle. Increased tibial slope resulted in tight component gap at knee extension compared with that at knee flexion. Furthermore, tight component gap at extension lead to decreased postoperative extension angle. These results indicate that an individual anatomical tibial slope should be considered when tibial sagittal osteotomy was performed and increasing tibial slope should be avoided to achieve full extension angle after UKA. II. Copyright © 2016. Published by Elsevier B.V.

  18. Validation of a computer-assisted method for measurement of radiographic wear in total hip arthroplasty using all polyethylene cemented acetabular components.

    PubMed

    Langlois, Jean; Zaoui, Amine; Scemama, Caroline; Martell, John; Bragdon, Charles; Hamadouche, Moussa

    2015-03-01

    Although cemented all polyethylene (PE) cups have been routinely used in total hip arthroplasty for decades, no computer-assisted method for measurement of radiographic wear has ever been specifically validated for these implants. Using a validated hip phantom model, AP plain hip radiographs were obtained consecutively for eight simulated wear positions. A version of Martell's Hip Analysis Suite software dedicated to all polyethylene sockets was used by three different examiners of varied experience. Bias (mean, standard deviation and 95% confidence interval limit), repeatability (standard deviation and 95% limit) and reproducibility (standard deviation and 95% limit) for two-dimensional wear measurements were assessed, as recommended by the current ASTM guidelines. Using this protocol, the dedicated software showed an overall mean bias of 0.089 ± 0.060 mm (mean ± SD), and 0.118 mm for 95% CI limit. Repeatability (intra examiner) standard deviation and 95% limit were respectively 0.106 mm and 0.292 mm. Reproducibility (inter examiner) standard deviation and 95% limit were respectively 0.112 mm and 0.308 mm. Martell Hip Analysis for all PE cemented cups is a reliable and low-cost instrument in the assessment of wear, despite being less precise than its original version dedicated to cementless components. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  19. Bone cement

    PubMed Central

    Vaishya, Raju; Chauhan, Mayank; Vaish, Abhishek

    2013-01-01

    The knowledge about the bone cement is of paramount importance to all Orthopaedic surgeons. Although the bone cement had been the gold standard in the field of joint replacement surgery, its use has somewhat decreased because of the advent of press-fit implants which encourages bone in growth. The shortcomings, side effects and toxicity of the bone cement are being addressed recently. More research is needed and continues in the field of nanoparticle additives, enhanced bone–cement interface etc. PMID:26403875

  20. Bone cement.

    PubMed

    Vaishya, Raju; Chauhan, Mayank; Vaish, Abhishek

    2013-12-01

    The knowledge about the bone cement is of paramount importance to all Orthopaedic surgeons. Although the bone cement had been the gold standard in the field of joint replacement surgery, its use has somewhat decreased because of the advent of press-fit implants which encourages bone in growth. The shortcomings, side effects and toxicity of the bone cement are being addressed recently. More research is needed and continues in the field of nanoparticle additives, enhanced bone-cement interface etc.

  1. Does cementing the femoral component increase the risk of peri-operative mortality for patients having replacement surgery for a fracture of the neck of femur? Data from the National Hip Fracture Database.

    PubMed

    Costa, M L; Griffin, X L; Pendleton, N; Pearson, M; Parsons, N

    2011-10-01

    Concerns have been reported to the United Kingdom National Patient Safety Agency, warning that cementing the femoral component during hip replacement surgery for fracture of the proximal femur may increase peri-operative mortality. The National Hip Fracture Database collects demographic and outcome data about patients with a fracture of the proximal femur from over 100 participating hospitals in the United Kingdom. We conducted a mixed effects logistic regression analysis of this dataset to determine whether peri-operative mortality was increased in patients who had undergone either hemiarthroplasty or total hip replacement using a cemented femoral component. A total of 16,496 patients from 129 hospitals were included in the analysis, which showed a small but significant adjusted survival benefit associated with cementing (odds ratio 0.83, 95% confidence interval 0.72 to 0.96). Other statistically significant variables in predicting death at discharge, listed in order of magnitude of effect, were gender, American Society of Anesthesiologists grade, age, walking accompanied outdoors and arthroplasty. Interaction terms between cementing and these other variables were sequentially added to, but did not improve, the model. This study has not shown an increase in peri-operative mortality as a result of cementing the femoral component in patients requiring hip replacement following fracture of the proximal femur.

  2. Lateralization of Tibial Plateau Reference Point Improves Accuracy of Tibial Resection in Total Knee Arthroplasty in Patients with Proximal Tibia Vara.

    PubMed

    Thippana, Rajshekhar K; Kumar, Malhar N

    2017-12-01

    The tibial cut referenced to the center of the intercondylar eminence often leads to varus malalignment in the presence of preexisting proximal tibia vara. The purpose of this study was to investigate the effect of lateralization of the lateral tibial plateau reference point (based on the amount of proximal tibia vara) on the postoperative coronal plane alignment. In this prospective cohort study, 62 patients (95 knees) with osteoarthritis and proximal tibia vara underwent primary total knee arthroplasty using a lateral tibial plateau reference point for the extramedullary jig. The pre- and postoperative radiographs were obtained for measurement of mechanical axis deviation, degree of tibia vara, proximal lateral reference point of the tibial condyle, and coronal alignment of the femoral and tibial components. The distance between the tibial reference point and the center of the intercondylar eminence was measured intraoperatively. The mean tibia vara was 7.1° (standard deviation [SD], 2.3°). The mean lateral displacement of the reference point was 7 mm (SD, 2.2 mm). Postoperative tibiofemoral angle was 6° to 10° of valgus in 94% of cases. There was a strong correlation between the magnitude of tibia vara and the amount of lateralization of the tibial reference point (R2 = 0.79, p < 0.001). In total knee arthroplasty patients with proximal tibia vara, reasonable accuracy can be achieved with use of the extramedullary jig for tibial component alignment by lateralizing the proximal tibial reference point.

  3. High Tibial Osteotomy

    PubMed Central

    Byun, Seong Joon

    2012-01-01

    High tibial osteotomy (HTO) is a widely performed procedure to treat medial knee arthrosis. In general, published studies on HTO report good long-term results with a correct patient selection and a precise surgical technique. The ideal candidate for an HTO is a middle aged patient (60 to 65 years of age), with isolated medial osteoarthritis, with good range of motion and without ligamentous instability. Some issues that need resolution remain; these include the choice between opening and closing wedge tibial osteotomy, the graft selection in opening wedge osteotomies, the type of fixation, the comparison with unicompartmental knee arthroplasty and whether HTO significantly affects a subsequent total joint replacement. Precise indication, preoperative planning, and operative technique selection are essential to achieve good results. PMID:22708105

  4. Detection and Analysis of the Magnetic Field Component of Electromagnetic Radiation Emission from Macroscopic Fracturing of Cement-Bound Granular Material

    NASA Astrophysics Data System (ADS)

    Maquiling, J. T.; Ceralde, P. I. B.

    2016-12-01

    Countries most prone to earthquake damage have been in pursuit of a possible earthquake precursor. This study aims to detect and measure the magnetic field component of the Electromagnetic Radiation (EMR) emitted by quasi-brittle materials that undergo macroscopic fracturing. Cement-Bound Granular Materials (CBGM) were prepared by mixing cement, sand and gravel in a beam mold. Additional aggregates in the form of saw dust were added to produce variable CBGM samples. A concrete beam holder was designed and fabricated such that induced cracks from impact loading would form at the center of the beam. Six Vernier software magnetic field sensors were used to detect the magnetic field (MF) component of the EMR emission. Initial calibration was done to minimize noise in the laboratory. The magnetic field sensors were set at a low amplification range (±6.4x10-3 T) setting with 0.0002 mT precision at 20-50 Hz. Sensor locations and orientations were specified and fixed throughout the experiment. The impact loading process was repeated until concrete failure. The time of drop was determined through the occurrence of peak sound levels (dB) induced by the collision noise using a sound level meter at fast time weighting. Magnetic field fluctuations manifesting near the occurrence of sound level impulses were recorded. Peak magnetic field values within ±200ms from the recorded time of impact were considered to be originating from the concrete fracture. Concrete samples consisting of cement, sand and gravel produced magnetic field emissions measuring 0.58-1.07 μT while the same concrete mixture added with dispersed fine sawdust released 0.55-1.28 μT. A more dispersed set of values of magnetic field emissions were observed for concrete with sawdust. Comparison between the average number of drops done before failure occurs between the two concrete mixtures also indicated that the addition of dispersed sawdust resulted to weaker CBGM samples. Upon increasing input energy from

  5. Metal-backed versus all-polyethylene unicompartmental knee arthroplasty: Proximal tibial strain in an experimentally validated finite element model.

    PubMed

    Scott, C E H; Eaton, M J; Nutton, R W; Wade, F A; Evans, S L; Pankaj, P

    2017-01-01

    Up to 40% of unicompartmental knee arthroplasty (UKA) revisions are performed for unexplained pain which may be caused by elevated proximal tibial bone strain. This study investigates the effect of tibial component metal backing and polyethylene thickness on bone strain in a cemented fixed-bearing medial UKA using a finite element model (FEM) validated experimentally by digital image correlation (DIC) and acoustic emission (AE). A total of ten composite tibias implanted with all-polyethylene (AP) and metal-backed (MB) tibial components were loaded to 2500 N. Cortical strain was measured using DIC and cancellous microdamage using AE. FEMs were created and validated and polyethylene thickness varied from 6 mm to 10 mm. The volume of cancellous bone exposed to < -3000 µε (pathological loading) and < -7000 µε (yield point) minimum principal (compressive) microstrain and > 3000 µε and > 7000 µε maximum principal (tensile) microstrain was computed. Experimental AE data and the FEM volume of cancellous bone with compressive strain < -3000 µε correlated strongly: R = 0.947, R2 = 0.847, percentage error 12.5% (p < 0.001). DIC and FEM data correlated: R = 0.838, R2 = 0.702, percentage error 4.5% (p < 0.001). FEM strain patterns included MB lateral edge concentrations; AP concentrations at keel, peg and at the region of load application. Cancellous strains were higher in AP implants at all loads: 2.2- (10 mm) to 3.2-times (6 mm) the volume of cancellous bone compressively strained < -7000 µε. AP tibial components display greater volumes of pathologically overstrained cancellous bone than MB implants of the same geometry. Increasing AP thickness does not overcome these pathological forces and comes at the cost of greater bone resection.Cite this article: C. E. H. Scott, M. J. Eaton, R. W. Nutton, F. A. Wade, S. L. Evans, P. Pankaj. Metal-backed versus all-polyethylene unicompartmental knee arthroplasty: Proximal tibial strain in an experimentally validated finite

  6. Role of aluminous component of fly ash on the durability of Portland cement-fly ash pastes in marine environment

    SciTech Connect

    Lorenzo, MaP.; Goni, S.; Guerrero, A

    2003-07-01

    The durability, of mixtures of two kinds of Spanish fly ashes from coal combustion (ASTM class F) with 0, 15 and 35% replacement of Portland cement by fly ash, in a simulated marine environment (Na{sub 2}SO{sub 4}+NaCl solution of equivalent concentration to that of sea water: 0.03 and 0.45 M for sulphate and chloride, respectively), has been studied for a period of 90 days. The resistance of the different mixtures to the attack was evaluated by means of the Koch-Steinegger test. The results showed that all the mixtures were resistant, in spite of the great amount of Al{sub 2}O{sub 3} content of the fly ash. The diffusion of SO{sub 4}{sup 2-}, Na{sup +} and Cl{sup -} ions through the pore solution activated the pozzolanic reactivity of the fly ashes causing the corresponding microstructure changes, which were characterized by X-ray diffraction (XRD), mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). As a result, the flexural strength of the mixtures increased, principally for the fly ash of a lower particle size and 35% of addition.

  7. Mineral of the month: cement

    USGS Publications Warehouse

    van Oss, Hendrik G.

    2006-01-01

    Hydraulic cement is a virtually ubiquitous construction material that, when mixed with water, serves as the binder in concrete and most mortars. Only about 13 percent of concrete by weight is cement (the rest being water and aggregates), but the cement contributes all of the concrete’s compressional strength. The term “hydraulic” refers to the cement’s ability to set and harden underwater through the hydration of the cement’s components.

  8. Effects of measurement methods for tibial rotation axis on the morphometry in Korean populations by gender.

    PubMed

    Kang, Kyoung-Tak; Son, Juhyun; Kwon, Oh-Ryong; Baek, Changhyun; Heo, Dong Beom; Park, Kyoung-Mi; Kim, Ho-Joong; Koh, Yong-Gon

    2017-01-01

    There have been arguments for methodology in tibial rotation axis measurement, which accordingly determines the morphometry of the proximal tibia in total knee arthroplasty. The morphometry of the proximal tibia for the Korean population is determined by gender, based on the anatomical tibial axis and reliable rotational orientation in knee replacements, to evaluate the size suitability of the currently available prostheses in Korea. This study reconstructed the MRI images in three-dimensions for identification and measurement of the mediolateral (ML) and anteroposterior (AP) lengths of the proximal tibia and the tibial aspect ratio (ML/AP) using proximal tibial anthropometric data for 700 osteoarthritic knees (587 females and 113 males). The ML and AP lengths were measured using tibial rotation axis techniques based on the medial one-third tibial tubercle and Cobb's method. Significant differences (P<0.05) in ML, medial anteroposterior (MAP), lateral anteroposterior (LAP) lengths, and aspect ratio (ML/LAP) were observed for males and females with respect to different measurement techniques for the tibial rotation axis. However, the measured aspect ratio (ML/MAP) of tibiae for the Korean population did not show significance. The measured aspect ratio (ML/AP) ratio of tibiae for the Korean population was higher than that of currently available tibial components. Results from this study can guide development of gender-specific tibial prosthesis designs with different ML and AP aspect ratios based on the tibial anatomical rotation axis for the Korean population. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Optimization of a Functionally Graded Material Stem in the Femoral Component of a Cemented Hip Arthroplasty: Influence of Dimensionality of FGM

    PubMed Central

    Yadav, Rohan

    2017-01-01

    The longevity of hip prostheses is contingent on the stability of the implant within the cavity of the femur bone. The cemented fixation was mostly adopted owing to offering the immediate stability from cement-stem and cement-bone bonding interfaces after implant surgery. Yet cement damage and stress shielding of the bone were proven to adversely affect the lifelong stability of the implant, especially among younger subjects who tend to have an active lifestyle. The geometry and material distribution of the implant can be optimized more efficiently with a three-dimensional realistic design of a functionally graded material (FGM). We report an efficient numerical technique for achieving this objective, for maximum performance stress shielding and the rate of early accumulation of cement damage were concurrently minimized. Results indicated less stress shielding and similar cement damage rates with a 2D-FGM implant compared to 1D-FGM and Titanium alloy implants. PMID:28717644

  10. Pediatric Tibial Osteomyelitis.

    PubMed

    Stone, Brad; Street, Matthew; Leigh, Warren; Crawford, Haemish

    2016-01-01

    Osteomyelitis shows a strong predilection for the tibia in the pediatric population and is a significant source of complications. The purpose of this article is to retrospectively review a large series of pediatric patients with tibial osteomyelitis. We compare our experience with that in the literature to determine any factors that may aid diagnosis and/or improve treatment outcomes. A 10-year retrospective review was performed of clinical records of all cases of pediatric tibial osteomyelitis managed at the 2 children's orthopaedic departments in the Auckland region. The Osteomyelitis Database was used to identify all cases between 1997 and 2007, at Starship Children's Hospital, and 1998 and 2008 at Middlemore's Kids First Hospital. One hundred ninety-one patients fulfilled the inclusion criteria, and had a review of clinical notes and relevant investigations. The average duration of symptoms before presentation to hospital was 5.7 days. Less than 40% of patients had a recent episode of trauma. Almost 60% of patients could not bear weight on admission. Over 40% of patients had a temperature above 38°C. Erythrocyte sedimentation rate was elevated in 78% and the C-reactive protein was elevated in 90% of patients. In total, 42% of blood cultures and almost 75% of tissue cultures were positive, with Staphylococcus aureus being the most commonly cultured organism. X-rays, bone scans, and magnetic resonance imaging were all used to aid the diagnosis. About 43% of patients had surgery. Treatment length was an average of 2 weeks 6 days of intravenous antibiotics followed by 3 weeks 2 days of oral treatment. Six postsurgical complications and 46 readmissions were noted: 25 for relapse, with the remainder due to social and antibiotic-associated complications. Although generally diagnosed on presentation, pediatric tibial osteomyelitis can require more sophisticated investigations and prolonged management. Treatment with intravenous and oral antibiotics and surgical

  11. Anterior tibial striations.

    PubMed

    Daffner, R H

    1984-09-01

    Radiolucent horizontal striations of the anterior cortex of the tibia were seen in 10 athletes who were evaluated for "shin-splints." There were seven basketball players, two professional dancers, and one hurdler. Each patient's history included vigorous leaping in performance of athletic feats. All the lesions were similar in location and appearance and were accompanied by thickening of the anterior tibial cortex. These striations are considered stress fractures and were not observed in a group of runners who were evaluated for shin-splints.

  12. A novel technique using sensor-based technology to evaluate tibial tray rotation.

    PubMed

    Roche, Martin W; Elson, Leah C; Anderson, Christopher R

    2015-03-01

    Rotational tibiofemoral congruency and centralized patellar tracking are critical technical factors that affect the postoperative success of total knee arthroplasty (TKA). Several techniques are used to position the femoral component, but there is no validated method for achieving the ideal rotational position of the tibial component. It has been suggested that referencing the midmedial third of the tibial tubercle intraoperatively mitigates positional outliers. This study used data collected from intraoperative sensors to quantify the variability associated with using the midmedial third of the tibial tubercle in 170 patients undergoing primary TKA. With the sensor-equipped trial insert in place, the knee was taken into extension and the location of the femoral condylar contact point on the articular surface of the tibial insert was displayed. Rotational adjustments of the tibial tray were evaluated in real time as the surgeon corrected tray malpositioning. The initial and final angles of tibial tray rotation were captured and recorded with intraoperative video feed. When referencing the tubercle, 53% of patients had asymmetric tibiofemoral congruency in extension. Of those patients, 68% had excessive internal rotation of the tibial tray relative to the femur and 32% had excessive external rotation. The average tibiofemoral incongruency deviated from a neutral position by 6° (range, 0.5°-19.2°). Data from this evaluation suggest that use of the tibial tubercle to maximize tibiofemoral congruency is highly variable and inconsistent for confirming the final rotation of the tibial tray. Copyright 2015, SLACK Incorporated.

  13. The Exeter universal cemented femoral component at 8 to 12 years. A study of the first 325 hips.

    PubMed

    Williams, H D W; Browne, G; Gie, G A; Ling, R S M; Timperley, A J; Wendover, N A

    2002-04-01

    We describe our experience with the implantation of 325 Exeter Universal hips. The fate of every implant was known. The procedures were undertaken by surgeons of widely differing experience. At follow-up at 12 years, survivorship with revision of the femoral component for aseptic loosening as the endpoint was 100% (95% CI 98 to 100). Survivorship with revision of the acetabular component for aseptic loosening as the endpoint was 96.86% (95% CI 93.1 to 98.9) and that with any reoperation as the endpoint 91.74% (95% CI 87.7 to 95.8). No adverse features have emerged as a consequence of the modular connection between the head and neck of the implant.

  14. [PVD-silicoating before cementation of zirconia-based knee prostheses effects better cement adhesion and lower aseptic loosening rates].

    PubMed

    Marx, R; Faramarzi, R; Oberbach, T; Begand, S; Grätz, N; Wirtz, D C

    2012-02-01

    CoCrMo alloys are contraindicated for allergy patients. For these patients, cemented or uncemented prostheses made of titanium alloy are indicated. Uncemented prostheses, however, have low primary retention, particularly the tibial components of knee joint prostheses because of the lack of a positive locking. Therefore, for knee replacement cemented CoCrMo prostheses may be suitable also for allergy sufferers if these are masked by ZrN or TiNbN layers. Alternatively the CoCrMo alloy may be replaced by high-strength oxide ceramics. For adhesion of bone cement to the ceramic surface, however, only inefficient mechanical retention spots are exposed as compared with a metal surface. Undercuts generated by corundum blasting, although highly efficient on a CoCrMo surface, are not such efficient centres on a ceramic surface due to its brittleness. Therefore, the mechanical component of retention is significantly reduced. When specific adhesion between bone cement and surface does not exist due to physical and chemical forces, the hydrolytic stability will be insufficient. Micromotions are promoted and early aseptic loosening is predictable. Silicoating of the ceramic surface will allow specific adhesion and can result in better hydrolytic stability of bonding. In order to evaluate the effectiveness of silicoating the bond strengths of blasted (mean size of corundum grains 50 µm) and silicate layered alumina-toughened zirconia (ATZ) surfaces were compared with "as fired" surfaces by utilising TiAlV probes (diameter 6 mm) for traction-adhesive strength testing. Samples machined out of CoCrMo alloy were utilised for reference. After preparing the samples for traction-adhesive strength testing (sequence: substrate, silicate and silane, protective lacquer [PolyMA], bone cement, TiAlV probe) they were aged up to 360 days at 37 °C in Ringer's solution. The bond strengths observed for all ageing intervals were well above 20 MPa and much higher and more hydrolytically

  15. The Exeter Universal cemented femoral component at 15 to 17 years: an update on the first 325 hips.

    PubMed

    Carrington, N C; Sierra, R J; Gie, G A; Hubble, M J W; Timperley, A J; Howell, J R

    2009-06-01

    The first 325 Exeter Universal stems (309 patients) implanted at the originating centre were inserted between March 1988 and February 1990 by a group of surgeons with differing experience. In this report we describe the clinical and radiological results at a mean of 15.7 years (14.7 to 17.3) after operation with no loss to follow-up. There were 97 patients (108 hips) with replacements still in situ and 31 (31 hips) who had undergone a further procedure. With an endpoint of revision for aseptic loosening, the survivorship at 17 years was 100% and 90.4% for the femoral and acetabular component, respectively. The mean Merle D'Aubigné and Postel scores at review were 5.4 (SD 0.97) for pain and 4.5 (SD 1.72) for function. The mean Oxford score was 38.4 (SD 9.8) (0 to 48 worst-to-best scale) and the mean combined Harris pain and function score was 73.2 (SD 16.9). Radiological review showed excellent preservation of bone stock in the proximal femur and no failures of the femoral component.

  16. Surface damage versus tibial polyethylene insert conformity: a retrieval study.

    PubMed

    Wimmer, Markus A; Laurent, Michel P; Haman, Jeannie D; Jacobs, Joshua J; Galante, Jorge O

    2012-07-01

    Surface damage of the tibial polyethylene insert in TKA is thought to diminish with increasing conformity, based on computed lower contact stresses. Added constraint from higher conformity may, however, result in greater forces in vivo. We therefore determined whether increased conformity was associated with increased surface pitting, delamination, creep, and polishing in a group of retrieved tibial inserts. We compared 38 inserts with a dished articular surface (conforming group) with 31 inserts that were unconstrained and nonconforming in the sagittal plane (less conforming group). The two groups had identical polyethylene composition and processing history. The articulating surfaces were scored for pitting, delamination, deformation/creep, and polishing. Evidence of edge loading and the presence of embedded bone cement were also recorded. The conforming inserts were associated with higher delamination and pitting scores but lower polishing scores, even after adjusting for the effects of sex, age, insert thickness, and implantation duration. Long implantation duration and male sex were also associated with increased delamination, pitting, and polishing, whereas long shelf life was associated only with increased delamination. The conforming group also had approximately a fourfold greater prevalence of edge loading and approximately a threefold greater prevalence of embedded bone cement. The latter was associated with higher scores and proportions of delamination and pitting. These findings suggest more conformity may increase surface fatigue damage in TKA. Higher constraint-induced stresses during secondary motions and more possibility for edge loading and bone cement capture on a dished surface may account for these results. The selection of materials with high fatigue resistance may be particularly important for high-conformity/constraint tibial inserts. In addition, awareness of the benefits and trade-offs with conformity may allow better matching of TKA design

  17. Modeling of the polluting emissions from a cement production plant by partial least-squares, principal component regression, and artificial neural networks.

    PubMed

    Marengo, Emilio; Bobba, Marco; Robotti, Elisa; Liparota, Maria Cristina

    2006-01-01

    A Portland cement process was taken into consideration and monitored for one month with respect to polluting emissions, fuel and raw material physical-chemical properties, and operative conditions. Soft models, based on linear (partial least-squares, PLS, and principal component regression, PCR) and nonlinear (artificial neural networks, ANNs) approaches, were employed to predict the polluting emissions. The predictive ability of the three regression methods was evaluated by means of the partition of the dataset by Kohonen self-associative maps into both a training and a test set. Then, a "leave-more-out" approach, based on the use of a training set, a test set, and a production set, was adopted. The training set was used to build the models, the test set was used to select the number of latent variables or the neural network training endpoint, and the production set was used to produce genuine predictions. ANNs proved to be much more effective in prediction with respect to PLS and PCR and, at least in the case of SO2 and dust, provided a predictive ability comparable with the experimental estimated uncertainty of the response. This showed that it is possible to satisfactorily predict the two responses. Such a prediction will result in the prevention of environmental and legal problems connected to the polluting emissions.

  18. The effect of high tibial osteotomy on the results of total knee arthroplasty: a matched case control study

    PubMed Central

    van Raaij, Tom M; Bakker, Wouter; Reijman, Max; Verhaar, Jan AN

    2007-01-01

    Background We performed a matched case control study to assess the effect of prior high tibia valgus producing osteotomy on results and complications of total knee arthroplasty (TKA). Methods From 1996 until 2003 356 patients underwent all cemented primary total knee replacement in our institution. Twelve patients with a history of 14 HTO were identified and matched to a control group of 12 patients with 14 primary TKA without previous HTO. The match was made for gender, age, date of surgery, body mass index, aetiology and type of prosthesis. Clinical and radiographic outcome were evaluated after a median duration of follow-up of 3.7 years (minimum, 2.3 years). The SPSS program was used for statistical analyses. Results The index group had more perioperative blood loss and exposure difficulties with one tibial tuberosity osteotomy and three patients with lateral retinacular releases. No such procedures were needed in the control group. Mid-term HSS, KSS and WOMAC scores were less favourable for the index group, but these differences were not significant. The tibial slope of patients with prior HTO was significantly decreased after this procedure. The tibial posterior inclination angle was corrected during knee replacement but posterior inclination was significantly less compared to the control group. No deep infection or knee component loosening were seen in the group with prior HTO. Conclusion We conclude that TKA after HTO seems to be technically more demanding than a primary knee arthroplasty, but clinical outcome was almost identical to a matched group that had no HTO previously. PMID:17683549

  19. Bi-cruciate stabilized total knee arthroplasty can reduce the risk of knee instability associated with posterior tibial slope.

    PubMed

    Hada, Masaru; Mizu-Uchi, Hideki; Okazaki, Ken; Kaneko, Takao; Murakami, Koji; Ma, Yuan; Hamai, Satoshi; Nakashima, Yasuharu

    2017-09-22

    The purpose of this study was to evaluate the relationship between posterior tibial slope and knee kinematics in bi-cruciate stabilized (BCS) total knee arthroplasty (TKA), which has not been previously reported. This computer simulation study evaluated Journey 2 BCS components (Smith & Nephew, Inc., Memphis, TN, USA) implanted in a female patient to simulate weight-bearing stair climbing. Knee kinematics, patellofemoral contact forces, and quadriceps forces during stair climbing (from 86° to 6° of flexion) were computed in the simulation. Six different posterior tibial slope angles (0°-10°) were simulated to evaluate the effect of posterior tibial slope on knee kinematics and forces. At 65° of knee flexion, no anterior sliding of the tibial component occurred if the posterior tibial slope was less than 10°. Anterior contact between the anterior aspect of the tibial post- and the femoral component was observed if the posterior tibial slope was 6° or more. An increase of 10° in posterior tibial slope (relative to 0°) led to a 4.8% decrease in maximum patellofemoral contact force and a 1.2% decrease in maximum quadriceps force. BCS TKA has a wide acceptable range of posterior tibial slope for avoiding knee instability if the posterior tibial slope is less than 10°. Surgeons should prioritize avoiding adverse effects over trying to achieve positive effects such as decreasing patellofemoral contact force and quadriceps force by increasing posterior tibial slope. Our study helps surgeons determine the optimal posterior tibial slope during surgery with BCS TKA; posterior tibial slope should not exceed 10° in routine clinical practice.

  20. Peri-Implant Distribution of Polyethylene Debris in Postmortem-Retrieved Knee Arthroplasties: Can Polyethylene Debris Explain Loss of Cement-Bone Interlock in Successful Total Knee Arthroplasties?

    PubMed

    Cyndari, Karen I; Goodheart, Jacklyn R; Miller, Mark A; Oest, Megan E; Damron, Timothy A; Mann, Kenneth A

    2017-07-01

    Loss of mechanical interlock between cement and bone with in vivo service has been recently quantified for functioning, nonrevised, cemented total knee arthroplasties (TKAs). The cause of interlocking trabecular resorption is not known. The goal of this study is to quantify the distribution of PE debris at the cement-bone interface and determine if polyethylene (PE) debris is locally associated with loss of interlock. Fresh, nonrevised, postmortem-retrieved TKAs (n = 8) were obtained en bloc. Laboratory-prepared constructs (n = 2) served as negative controls. The intact cement-bone interface of each proximal tibia was embedded in Spurr's resin, sectioned, and imaged under polarized light to identify birefringent PE particles. PE wear particle number density was quantified at the cement-bone interface and distal to the interface, and then compared with local loss of cement-bone interlock. The average PE particle number density for postmortem-retrieved TKAs ranged from 8.6 (1.3) to 24.9 (3.1) particles/mm 2 (standard error) but was weakly correlated with years in service. The average particle number density was twice as high as distal (>5mm) to the interface compared to at the interface. The local loss of interlock at the interface was not related to the presence, absence, or particle density of PE. PE debris can migrate extensively along the cement-bone interface of well-fixed tibial components. However, the amount of local bone loss at the cement-bone interface was not correlated with the amount of PE debris at the interface, suggesting that the observed loss of trabecular interlock in these well-fixed TKAs may be due to alternative factors. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Medial tibial stress syndrome.

    PubMed

    Reshef, Noam; Guelich, David R

    2012-04-01

    MTSS is a benign, though painful, condition, and a common problem in the running athlete. It is prevalent among military personnel, runners, and dancers, showing an incidence of 4% to 35%. Common names for this problem include shin splints, soleus syndrome, tibial stress syndrome, and periostitis. The exact cause of this condition is unknown. Previous theories included an inflammatory response of the periosteum or periosteal traction reaction. More recent evidence suggests a painful stress reaction of bone. The most proven risk factors are hyperpronation of the foot, female sex, and history of previous MTSS. Patient evaluation is based on meticulous history taking and physical examination. Even though the diagnosis remains clinical, imaging studies, such as plain radiographs and bone scans are usually sufficient, although MRI is useful in borderline cases to rule out more significant pathology. Conservative treatment is almost always successful and includes several options; though none has proven more superior to rest. Prevention programs do not seem to influence the rate of MTSS, though shock-absorbing insoles have reduced MTSS rates in military personnel, and ESWT has shortened the duration of symptoms. Surgery is rarely indicated but has shown some promising results in patients who have not responded to all conservative options.

  2. 76 FR 78240 - Gray Portland Cement and Clinker From Japan: Continuation of Antidumping Duty Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-16

    ... Review)). Scope of the Order The products covered by the order are cement and cement clinker from Japan. Cement is a hydraulic cement and the primary component of concrete. Cement clinker, an intermediate... product description remains dispositive as to the scope of the product covered by the order.\\2\\ \\2\\ The...

  3. [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.

  4. Evaluation of tibial rotational alignment in total knee arthroplasty: a cadaver study.

    PubMed

    Rossi, Roberto; Bruzzone, Matteo; Bonasia, Davide Edoardo; Marmotti, Antonio; Castoldi, Filippo

    2010-07-01

    Various techniques exist for establishing tibial rotational alignment during total knee arthroplasty (TKA). The purpose of this study is to establish the most precise and reproducible method to assess tibial component rotational alignment during TKA by comparing the flexion-extension technique (ROM) and the Posterior-lateral Corner Locked Technique (PLCL). Twenty posterior stabilized TKAs were performed on cadavers. The rotation angles of the tibial components obtained using the two techniques were evaluated. The tibial component rotation axis obtained using the ROM technique and the PLCL method averaged, respectively, 0.35 degrees (+ or - 4.2 degrees ) externally rotated and 0.34 degrees (+ or - 3 degrees ) internally rotated to the Akagi line. No significant differences between the two methods were found and a high correlation exists between the two techniques (Pearson's coefficient = 0.88). The ROM and PLCL techniques are both precise and reproducible methods to assess tibial component rotation during TKA. However, while the ROM technique is dependent on the correct positioning of the femoral component and the soft tissue balancing, the PCLC method is easier if a complete visualization of the posterior-lateral corner of the cut tibial plateau is achieved.

  5. A preclinical numerical assessment of a polyetheretherketone femoral component in total knee arthroplasty during gait.

    PubMed

    de Ruiter, Lennert; Janssen, Dennis; Briscoe, Adam; Verdonschot, Nico

    2017-12-01

    Conventional total knee replacement designs show high success rates but in the long term, the stiff metal components may affect bone quality of the distal femur. In this study we introduce an all-polymer total knee replacement device containing a PEEK femoral component on an UHMWPE tibial implant and study its mechanical integrity, fixation, and stress shielding of the periprosthetic femur. The implant was analysed in finite element simulations of level gait, adopted from the ISO 14243-1 standard. Mechanical integrity of the implant and underlying cement mantle were tested, and the fixation strength of the cement-implant interface was studied. Stress shielding was assessed based on strain energy density distributions in the distal femur. We compared PEEK and CoCr implants for mechanical performance and fixation, and compared both versions against an intact case to determine the change in bone strain energy density. The mechanical integrity of the PEEK and CoCr components was similar in magnitude, but differences in stress patterns were found. Moreover, the cement mantle was loaded more heavily in the CoCr configuration. Under similar interface properties, the CoCr-cement interface was more at risk of failure than the PEEK-cement interface. The bone strain energy density distribution of the PEEK implant was similar to the intact case, while the CoCr implant showed signs of stress shielding, and a different distribution than the intact and PEEK models. During gait, the PEEK femoral component performed similarly to CoCr, with no added risk for the cement mantle. The reduction in stress shielding for PEEK was evident and confirms the potential reduction in long-term loss of bone stock for this all-polymer knee implant.

  6. A randomised controlled trial comparing highly cross-linked and contemporary annealed polyethylene after a minimal eight-year follow-up in total hip arthroplasty using cemented acetabular components.

    PubMed

    Langlois, J; Atlan, F; Scemama, C; Courpied, J P; Hamadouche, M

    2015-11-01

    Most published randomised controlled trials which compare the rates of wear of conventional and cross-linked (XL) polyethylene (PE) in total hip arthroplasty (THA) have described their use with a cementless acetabular component. We conducted a prospective randomised study to assess the rates of penetration of two distinct types of PE in otherwise identical cemented all-PE acetabular components. A total of 100 consecutive patients for THA were randomised to receive an acetabular component which had been either highly XL then remelted or moderately XL then annealed. After a minimum of eight years follow-up, 38 hips in the XL group and 30 hips in the annealed group had complete data (mean follow-up of 9.1 years (7.6 to 10.7) and 8.7 years (7.2 to 10.2), respectively). In the XL group, the steady state rate of penetration from one year onwards was -0.0002 mm/year (sd 0.108): in the annealed group it was 0.1382 mm/year (sd 0.129) (Mann-Whitney U test, p < 0.001). No complication specific to either material was recorded. These results show that the yearly linear rate of femoral head penetration can be significantly reduced by using a highly XLPE cemented acetabular component. ©2015 The British Editorial Society of Bone & Joint Surgery.

  7. An implantable telemetry device to measure intra-articular tibial forces.

    PubMed

    D'Lima, Darryl D; Townsend, Christopher P; Arms, Steven W; Morris, Beverly A; Colwell, Clifford W

    2005-02-01

    Tibial forces are important because they determine polyethylene wear, stress distribution in the implant, and stress transfer to underlying bone. Theoretic estimates of tibiofemoral forces have varied between three and six times the body weight depending on the mathematical models used and the type of activity analyzed. An implantable telemetry system was therefore developed to directly measure tibiofemoral compressive forces. This system was tested in a cadaver knee in a dynamic knee rig. A total knee tibial arthroplasty prosthesis was instrumented with four force transducers located at the four corners of the tibial tray. These transducers measured the total compressive forces on the tibial tray and the location of the center of pressure. A microprocessor performed analog-to-digital signal conversion and performed pulse code modulation of a surface acoustic wave radio frequency oscillator. This signal was then transmitted through a single pin hermetic feed-through tantalum wire antenna located at the tip of the stem. The radio frequency signal was received by an external antenna connected to a receiver and to a computer for data acquisition. The prosthesis was powered by external coil induction. The tibial transducer accurately measured both the magnitude and the location of precisely applied external loads. Successful transmission of the radio frequency signal up to a range of 3m was achieved through cadaveric bone, bone cement, and soft tissue. Reasonable accuracy was obtained in measuring loads applied through a polyethylene insert. The implant was also able to detect unicondylar loading with liftoff.

  8. 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.

  9. Frozen delivery of brushite calcium phosphate cements.

    PubMed

    Grover, Liam M; Hofmann, Michael P; Gbureck, Uwe; Kumarasami, Balamurgan; Barralet, Jake E

    2008-11-01

    Calcium phosphate cements typically harden following the combination of a calcium phosphate powder component with an aqueous solution to form a matrix consisting of hydroxyapatite or brushite. The mixing process can be very important to the mechanical properties exhibited by cement materials and consequently when used clinically, since they are usually hand-mixed their mechanical properties are prone to operator-induced variability. It is possible to reduce this variability by pre-mixing the cement, e.g. by replacing the aqueous liquid component with non-reactive glycerol. Here, for the first time, we report the formation of three different pre-mixed brushite cement formulations formed by freezing the cement pastes following combination of the powder and liquid components. When frozen and stored at -80 degrees C or less, significant degradation in compression strength did not occur for the duration of the study (28 days). Interestingly, in the case of the brushite cement formed from the combination of beta-tricalcium phosphate with 2 M orthophosphoric acid solution, freezing the cement paste had the effect of increasing mean compressive strength fivefold (from 4 to 20 MPa). The increase in compression strength was accompanied by a reduction in the setting rate of the cement. As no differences in porosity or degree of reaction were observed, strength improvement was attributed to a modification of crystal morphology and a reduction in damage caused to the cement matrix during manipulation.

  10. Lunar cement

    NASA Astrophysics Data System (ADS)

    Agosto, William N.

    With the exception of water, the major oxide constituents of terrestrial cements are present at all nine lunar sites from which samples have been returned. However, with the exception of relatively rare cristobalite, the lunar oxides are not present as individual phases but are combined in silicates and in mixed oxides. Lime (CaO) is most abundant on the Moon in the plagioclase (CaAl2Si2O8) of highland anorthosites. It may be possible to enrich the lime content of anorthite to levels like those of Portland cement by pyrolyzing it with lunar-derived phosphate. The phosphate consumed in such a reaction can be regenerated by reacting the phosphorus product with lunar augite pyroxenes at elevated temperatures. Other possible sources of lunar phosphate and other oxides are discussed.

  11. Lunar cement

    NASA Technical Reports Server (NTRS)

    Agosto, William N.

    1992-01-01

    With the exception of water, the major oxide constituents of terrestrial cements are present at all nine lunar sites from which samples have been returned. However, with the exception of relatively rare cristobalite, the lunar oxides are not present as individual phases but are combined in silicates and in mixed oxides. Lime (CaO) is most abundant on the Moon in the plagioclase (CaAl2Si2O8) of highland anorthosites. It may be possible to enrich the lime content of anorthite to levels like those of Portland cement by pyrolyzing it with lunar-derived phosphate. The phosphate consumed in such a reaction can be regenerated by reacting the phosphorus product with lunar augite pyroxenes at elevated temperatures. Other possible sources of lunar phosphate and other oxides are discussed.

  12. 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

  13. A Novel Injectable Borate Bioactive Glass Cement as an Antibiotic Delivery Vehicle for Treating Osteomyelitis

    PubMed Central

    Cui, Xu; Gu, Yi-Fei; Jia, Wei-Tao; Rahaman, Mohamed N.; Wang, Yang; Huang, Wen-Hai; Zhang, Chang-Qing

    2014-01-01

    Background A novel injectable cement composed of chitosan-bonded borate bioactive glass (BG) particles was evaluated as a carrier for local delivery of vancomycin in the treatment of osteomyelitis in a rabbit tibial model. Materials and Methods The setting time, injectability, and compressive strength of the borate BG cement, and the release profile of vancomycin from the cement were measured in vitro. The capacity of the vancomycin-loaded BG cement to eradicate methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis in rabbit tibiae in vivo was evaluated and compared with that for a vancomycin-loaded calcium sulfate (CS) cement and for intravenous injection of vancomycin. Results The BG cement had an injectability of >90% during the first 3 minutes after mixing, hardened within 30 minutes and, after hardening, had a compressive strength of 18±2 MPa. Vancomycin was released from the BG cement into phosphate-buffered saline for up to 36 days, and the cumulative amount of vancomycin released was 86% of the amount initially loaded into the cement. In comparison, vancomycin was released from the CS cement for up 28 days and the cumulative amount released was 89%. Two months post-surgery, radiography and microbiological tests showed that the BG and CS cements had a better ability to eradicate osteomyelitis when compared to intravenous injection of vancomycin, but there was no significant difference between the BG and CS cements in eradicating the infection. Histological examination showed that the BG cement was biocompatible and had a good capacity for regenerating bone in the tibial defects. Conclusions These results indicate that borate BG cement is a promising material both as an injectable carrier for vancomycin in the eradication of osteomyelitis and as an osteoconductive matrix to regenerate bone after the infection is cured. PMID:24427311

  14. A novel injectable borate bioactive glass cement as an antibiotic delivery vehicle for treating osteomyelitis.

    PubMed

    Ding, Hao; Zhao, Cun-Ju; Cui, Xu; Gu, Yi-Fei; Jia, Wei-Tao; Rahaman, Mohamed N; Wang, Yang; Huang, Wen-Hai; Zhang, Chang-Qing

    2014-01-01

    A novel injectable cement composed of chitosan-bonded borate bioactive glass (BG) particles was evaluated as a carrier for local delivery of vancomycin in the treatment of osteomyelitis in a rabbit tibial model. The setting time, injectability, and compressive strength of the borate BG cement, and the release profile of vancomycin from the cement were measured in vitro. The capacity of the vancomycin-loaded BG cement to eradicate methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis in rabbit tibiae in vivo was evaluated and compared with that for a vancomycin-loaded calcium sulfate (CS) cement and for intravenous injection of vancomycin. The BG cement had an injectability of >90% during the first 3 minutes after mixing, hardened within 30 minutes and, after hardening, had a compressive strength of 18 ± 2 MPa. Vancomycin was released from the BG cement into phosphate-buffered saline for up to 36 days, and the cumulative amount of vancomycin released was 86% of the amount initially loaded into the cement. In comparison, vancomycin was released from the CS cement for up 28 days and the cumulative amount released was 89%. Two months post-surgery, radiography and microbiological tests showed that the BG and CS cements had a better ability to eradicate osteomyelitis when compared to intravenous injection of vancomycin, but there was no significant difference between the BG and CS cements in eradicating the infection. Histological examination showed that the BG cement was biocompatible and had a good capacity for regenerating bone in the tibial defects. These results indicate that borate BG cement is a promising material both as an injectable carrier for vancomycin in the eradication of osteomyelitis and as an osteoconductive matrix to regenerate bone after the infection is cured.

  15. Calcium sulfate cement in contained traumatic metaphyseal bone defects.

    PubMed

    Drosos, Georgios I; Ververidis, Athanasios; Babourda, Eleni C; Kakagia, Despoina; Verettas, Dionisios-Alexandros

    2012-12-01

    The aim of this study was to evaluate prospective patients with periarticular fractures where a meta physeal bone defect was grafted with high compressive calcium sulfate cement. The calcium sulfate cement MIIG X3, (Wright Medical Technology, Inc, Arlington, TN) was used in 45 patients with periarticular fractures--distal radial, tibial plateau, humeral head, and calcaneal fractures--to fill the metaphyseal defect. All fractures were treated either with open or closed reduction, fracture fixation, and the cement was applied openly or closed. Radiographs were evaluated for fracture reduction, joint line gap, and step, as well as for rate of graft replacement by bone. All fractures united without an additional procedure. There were no wound infections or other complications attributed to the graft. At three-month follow-up, a complete graft replacement by bone was observed in all fractures. Joint line step was not developed in any patient, but a joint line gap of 3 mm was observed postoperatively in one patient with a tibial plateau fracture. Loss of reduction occurred in one patient with an extra-articular distal radial fracture treated with closed reduction and k-wire fixation. Cement that escaped into the joint or the surrounding soft tissues was not visible at the six-week follow-up. In conclusion, the results of this study confirm the safety and the efficacy of this cement when it is used as graft with the appropriate fixation method in traumatic metaphyseal bone defects.

  16. Percutaneous plating of distal tibial fractures.

    PubMed

    Khoury, Amal; Liebergall, Meir; London, Eli; Mosheiff, Rami

    2002-09-01

    This article presents our experience with 24 patients who had distal tibial fractures and were treated by percutaneous plate fixation. Distribution of the fractures according to the AO/OTA classification was as follows: five patients suffered from a 43 A type fracture, six from a 43 B type fracture, and 13 from a 43 C type fractures. Four of the fractures were open. Exclusion criteria included 43 C3 fractures and Gustilo III open fractures. All fractures showed radiographic signs of union enough to enable full weightbearing within an average time of 12.3 weeks. All patients showed a good range of motion (average dorsiflexion 12 degrees and average plantiflexion 18 degrees). Two fractures united with mal-union: one with an 8 degrees valgus deformity and another with a 7 degrees varus deformity. Both cases, which had a metaphyseal component, were treated by means of a "soft" (flexible and manually adjustable) AO 3.5 mm reconstruction plate. Except for one case of superficial infection, no infections were detected in any of the patients. The biological percutaneous plate fixation of distal tibial fractures with no extensive intra-articular involvement is a good soft tissue preserving technique. It provides a rigid and anatomical fixation in most cases. We conclude that type B fractures with one intact column can be fixed with either "soft" or "rigid" plates, and type A and C fractures with a metaphyseal component should be fixed with "rigid" plates (AO 4.5 mm Dynamic Compression Plate). In these fractures the reduction should be performed cautiously due to the tendency of sagittal plane mal-reduction.

  17. Sculpting with Cement.

    ERIC Educational Resources Information Center

    Olson, Lynn

    1983-01-01

    Cement offers many creative possibilities for school art programs. Instructions are given for sculpting with fiber-cement and sand-cement, as well as for finishing processes and the addition of color. Safety is stressed. (IS)

  18. Influence of mediolateral tibial baseplate position in TKA on knee kinematics and retropatellar pressure.

    PubMed

    Steinbrück, Arnd; Fottner, Andreas; Schröder, Christian; Woiczinski, Matthias; Schmitt-Sody, Markus; Müller, Tatjana; Müller, Peter E; Jansson, Volkmar

    2017-08-01

    Anterior knee pain is a major reason for unsatisfied patients after total knee arthroplasty (TKA). Since malposition and increased retropatellar peak pressure are supposed to contribute to pain, we conducted this in vitro study to analyse the influence of mediolateral tibial component position on tibiofemoral and patella kinematics as well as retropatellar pressure. Eight fresh frozen cadaver specimens were tested after a fixed-bearing TKA. To evaluate the influence of mediolateral tibial component position, special inlays with 3 mm of medialization and lateralization were constructed. For the analysis, a weight-bearing knee rig under a loaded squat from 20° to 120° of flexion was used. Tibiofemoral and patella kinematics were measured with an ultrasonic-based three-dimensional motion analysis system. Additionally, retropatellar pressure distribution was registered with a pressure-sensitive film. Alteration of mediolateral tibial component position by 3 mm did not reveal a significant influence on retropatellar peak pressure (7.5 ± 2.5 vs. 7.2 ± 2.6 MPa). Regarding tibiofemoral kinematics, 3-mm medialization of the tibial baseplate significantly increased lateral femoral rollback and femorotibial external rotation. Medialization of 3 mm also significantly increased the relative medial patella shift and decreased lateral patella tilt. Medialization of the tibial baseplate came along with more lateral rollback and external femorotibial rotation. For the positioning of the tibial baseplate, rotational alignment seems to be more important than mediolateral orientation. Since retropatellar peak pressure remained rather unchanged, the tibial baseplate should be placed by the surgeon looking for a maximal tibial coverage without overhang.

  19. 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.

  20. True aneurysm of the anterior tibial artery.

    PubMed

    Leoce, Brian M; Bernik, Jack T; Gupta, Anjuli M; Dardik, Herbert; Bernik, Thomas R

    2018-02-05

    The majority of anterior tibial aneurysm cases described in the literature are pseudoaneurysms resulting from trauma 1-6 . Since 1967, only eight cases published on true anterior tibial artery aneurysms were atraumatic 7-9,16,17 . Recent experience with an atraumatic aneurysm of the anterior tibial artery prompted a literature review regarding their incidence, and accordingly, we feel the need exists for greater recognition and understanding of this entity. Copyright © 2018. Published by Elsevier Inc.

  1. 76 FR 54206 - Gray Portland Cement and Clinker From Japan: Final Results of the Expedited Third Sunset Review...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-31

    ... and clinker from Japan. Scope of the Order The products covered by the order are cement and cement clinker from Japan. Cement is a hydraulic cement and the primary component of concrete. Cement clinker, an... written product description remains dispositive as to the scope of the product covered by the order.\\2\\ \\2...

  2. Influence of temporary cement contamination on the surface free energy and dentine bond strength of self-adhesive cements.

    PubMed

    Takimoto, Masayuki; Ishii, Ryo; Iino, Masayoshi; Shimizu, Yusuke; Tsujimoto, Akimasa; Takamizawa, Toshiki; Ando, Susumu; Miyazaki, Masashi

    2012-02-01

    The surface free energy and dentine bond strength of self-adhesive cements were examined after the removal of temporary cements. The labial dentine surfaces of bovine mandibular incisors were wet ground with #600-grit SiC paper. Acrylic resin blocks were luted to the prepared dentine surfaces using HY Bond Temporary Cement Hard (HY), IP Temp Cement (IP), Fuji TEMP (FT) or Freegenol Temporary Cement (TC), and stored for 1 week. After removal of the temporary cements with an ultrasonic tip, the contact angle values of five specimens per test group were determined for the three test liquids, and the surface-energy parameters of the dentine surfaces were calculated. The dentine bond strengths of the self-adhesive cements were measured after removal of the temporary cements in a shear mode at a crosshead speed of 1.0mm/min. The data were subjected to one-way analysis of variance (ANOVA) followed by Tukey's HSD test. For all surfaces, the value of the estimated surface tension component γ(S)(d) (dispersion) was relatively constant at 41.7-43.3 mJm(-2). After removal of the temporary cements, the value of the γ(S)(h) (hydrogen-bonding) component decreased, particularly with FT and TC. The dentine bond strength of the self-adhesive cements was significantly higher for those without temporary cement contamination (8.2-10.6 MPa) than for those with temporary cement contamination (4.3-7.1 MPa). The γ(S) values decreased due to the decrease of γ(S)(h) values for the temporary cement-contaminated dentine. Contamination with temporary cements led to lower dentine bond strength. The presence of temporary cement interferes with the bonding performance of self-adhesive cements to dentine. Care should be taken in the methods of removal of temporary cement when using self-adhesive cements. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Catalytic behavior of graphene oxide for cement hydration process

    NASA Astrophysics Data System (ADS)

    Lin, Changqing; Wei, Wei; Hu, Yun Hang

    2016-02-01

    Hydration is a critical step that determines the performance of cement-based materials. In this paper, the effect of GO on the hydration of cement was evaluated by XRD and FTIR. It was found that GO can remarkably accelerate the hydration rate of cement due to its catalytic behavior. This happened because the oxygen-containing functional groups of GO provide adsorption sites for both water molecules and cement components.

  4. Parameters of Alumina Cement and Portland Cement with Addition of Chalcedonite Meal

    NASA Astrophysics Data System (ADS)

    Kotwa, Anna

    2017-10-01

    Aluminous cement is a quick binder with special properties. It is used primarily to make non-standard monolithic components exposed to high temperatures, + 1300°C. It is also a component of adhesives and mortars. It has a very short setting time. It is characterized by rapid increase in mechanical strength and resistance to aggressive sulphates. It can be used in reinforced concrete structures. Laying of concrete, construction mortar made of alumina cement can be carried out even at temperatures of -10°C. This article discusses a comparison of the parameters of hardened mortar made of alumina cement GÓRKAL 40 and Portland cement CEM I 42.5R. The mortars contain an addition of chalcedonite meal with pozzolanic properties, with particle size of less than 0.063μm. The meal was added in amounts of 5% and 20% of cement weight. Chalcedonite meal used in the laboratory research is waste material, resulting from chalcedonite aggregate mining. It has the same properties as the rock from which it originates. We have compared the parameters of hardened mortar i.e. compressive strength, water absorption and capillarity. The addition of 20% chalcedonite meal to mortars made from aluminous cement will decrease durability by 6.1% relative to aluminous cement mortar without addition of meal. Considering the results obtained during the absorbency tests, it can be stated that the addition of chalcedonite meal reduces weight gains in mortars made with cement CEM I 42.5 R and alumina cement. Use of alumina cement without addition of meal in mortars causes an increase of mass by 248% compared to Portland cement mortars without additions, in the absorption tests. The addition of chalcedonite meal did not cause increased weight gain in the capillary action tests. For the alumina cement mortars, a lesser weight gains of 24.7% was reported, compared to the Portland cement mortar after 28 days of maturing.

  5. Expansive Cements and Their Use

    DTIC Science & Technology

    1972-10-01

    cement is effective only when the hardened paste made with the cement is sufficiently restrained from expanding so that com- pressive stresses are...paper. EXPANSIVE CEMENTS An expansive cement is a cement which, when mixed with water, forms a paste , that during setting and after hardening...the Soviet Union . The Portland Cement Association developee type S cement . The USA producers of type H cement refer to their product as type MX cement

  6. Accuracy of a hand-held surgical navigation system for tibial resection in total knee arthroplasty.

    PubMed

    Bugbee, William D; Kermanshahi, Arash Y; Munro, Michelle M; McCauley, Julie C; Copp, Steven N

    2014-12-01

    Accuracy of total knee arthroplasty (TKA) implant placement and overall limb are important goals of TKA technique. The accuracy and ease of use of an accelerometer-based hand-held navigation system for tibial resection during TKA was examined in 90 patients. Preoperative goals for sagittal alignment, navigation system assembly time, resection time, and tourniquet time were evaluated. Coronal and sagittal alignment was measured postoperatively. The average coronal tibial component alignment was 0.43° valgus; 6.7% of patients had tibial coronal alignment outside of ±3° varus/valgus. The difference between the intraoperative goal and radiographically measured posterior tibial slope was 0.5°. The average time to completion of the tibial cut was 4.6 minutes. The accelerometer-based hand-held navigation system was accurate for tibial coronal and sagittal alignment during TKA, with no additional surgical time compared with conventional instrumentation. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. 21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... polyethylene. The femoral component has metallic runners which align with the ultra-high molecular weight polyethylene tracks that press-fit into the metallic tibial component. The generic class also includes devices...

  8. 21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... polyethylene. The femoral component has metallic runners which align with the ultra-high molecular weight polyethylene tracks that press-fit into the metallic tibial component. The generic class also includes devices...

  9. 21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... polyethylene. The femoral component has metallic runners which align with the ultra-high molecular weight polyethylene tracks that press-fit into the metallic tibial component. The generic class also includes devices...

  10. 21 CFR 888.3510 - Knee joint femorotibial metal/polymer constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... polyethylene. The femoral component has metallic runners which align with the ultra-high molecular weight polyethylene tracks that press-fit into the metallic tibial component. The generic class also includes devices...

  11. A new quantification method based on SEM-EDS to assess fly ash composition and study the reaction of its individual components in hydrating cement paste

    SciTech Connect

    Durdziński, Paweł T.; Dunant, Cyrille F.; Haha, Mohsen Ben; Scrivener, Karen L.

    2015-07-15

    Calcareous fly ashes are high-potential reactive residues for blended cements, but their qualification and use in concrete are hindered by heterogeneity and variability. Current characterization often fails to identify the dominant, most reactive, amorphous fraction of the ashes. We developed an approach to characterize ashes using electron microscopy. EDS element composition of millions of points is plotted in a ternary frequency plot. A visual analysis reveals number and ranges of chemical composition of populations: silicate, calcium-silicate, aluminosilicate, and calcium-rich aluminosilicate. We quantified these populations in four ashes and followed their hydration in two Portland-ash systems. One ash reacted at a moderate rate: it was composed of 70 vol.% of aluminosilicates and calcium-silicates and reached 60% reaction at 90 days. The other reacted faster, reaching 60% at 28 days due to 55 vol.% of calcium-rich aluminosilicates, but further reaction was slower and 15 vol.% of phases, the silica-rich ones, did not react.

  12. A new quantification method based on SEM-EDS to assess fly ash composition and study the reaction of its individual components in hydrating cement paste

    SciTech Connect

    Durdziński, Paweł T., E-mail: pawel.durdzinski@gmail.com; Dunant, Cyrille F.; Haha, Mohsen Ben

    2015-07-15

    Calcareous fly ashes are high-potential reactive residues for blended cements, but their qualification and use in concrete are hindered by heterogeneity and variability. Current characterization often fails to identify the dominant, most reactive, amorphous fraction of the ashes. We developed an approach to characterize ashes using electron microscopy. EDS element composition of millions of points is plotted in a ternary frequency plot. A visual analysis reveals number and ranges of chemical composition of populations: silicate, calcium-silicate, aluminosilicate, and calcium-rich aluminosilicate. We quantified these populations in four ashes and followed their hydration in two Portland-ash systems. One ash reacted at amore » moderate rate: it was composed of 70 vol.% of aluminosilicates and calcium-silicates and reached 60% reaction at 90 days. The other reacted faster, reaching 60% at 28 days due to 55 vol.% of calcium-rich aluminosilicates, but further reaction was slower and 15 vol.% of phases, the silica-rich ones, did not react.« less

  13. Primary total knee arthroplasty for elderly complex tibial plateau fractures.

    PubMed

    Huang, Jie-Feng; Shen, Jian-Jian; Chen, Jun-Jie; Tong, Pei-Jian

    2016-12-01

    The aim of this study is to evaluate the clinical and radiologic results of primary Total Knee Arthroplasty (TKA) for elderly complex tibial plateau fractures. Between November 2010 and February 2012, six cases of elderly complex tibial plateau fractures were treated with primary TKA using the standard medial parapatellar approach. All six patients were available at follow up with mean duration of 32.3 months (range 25-41 months). There were 3 women and 3 men with an average age of 69.5 years (58-78 years) at the time of the arthroplasty. The mean Hospital for Special Surgery (HSS) knee score was 89.8 (range 85-94): 6/6 excellent. The mean knee flexion was 119.2° (105-130°). No significant postoperative complications were noted. None of these patients had significant postoperative knee pain required revision surgery, or had radiographic loosening of the components at the latest follow-up. TKA is a suitable solution for the treatment of elderly patients with complex tibial plateau fractures. Level IV, Therapeutic study. Copyright © 2016 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

  14. Effects of tibial baseplate shape on rotational alignment in total knee arthroplasty: three-dimensional surgical simulation using osteoarthritis knees.

    PubMed

    Ma, Yuan; Mizu-Uchi, Hideki; Okazaki, Ken; Ushio, Tetsuro; Murakami, Koji; Hamai, Satoshi; Akasaki, Yukio; Nakashima, Yasuharu

    2018-01-01

    Placement of tibial component is expected to fulfill both maximum surface coverage and recommended anterior-posterior (AP) alignment in total knee arthroplasty (TKA). The purpose of this study is to evaluate the effect of the tibial baseplate shape on AP axis. Virtual surgery of TKA was performed with three-dimensional bone models reconstructed from 77 osteoarthritis varus knees. Two differently designed tibial baseplates, symmetrically and anatomically, were set to the cut surface under posterior slopes of 0°, 3°, and 7°. The AP axes were defined by connecting the geometrical center of the cut surface with the medial edge (axis MED) and medial 1/3 (axis 1/3MED) of patella tendon attachment. We evaluated the overhang rates as well as the most fitting AP axis which passes through the geometric center. Overhang rates when aligned to axis MED were 12-25% for the symmetrical-type group and 13-22% for the anatomical-type group. Overhang rates when aligned to axis 1/3MED were 42-48% for the symmetrical-type group and 3-7% for the anatomical-type group. The most fitting AP axis of tibial baseplate was located 2.5° external to axis MED for the symmetrical-type group and around 3.3° internal to axis 1/3MED for the anatomical-type group. Symmetrically or anatomically designed tibial baseplates have their own favored AP axis and specific performance on coverage. When aligned to axis 1/3MED, anatomically designed tibial baseplates will effectively lower the mismatch rates compared to a symmetrically designed tibial baseplate. Orthopaedic surgeons are expected to place the tibial components to the cut surface during TKA with full understanding of the features between different baseplate designs, AP axes, and posterior slopes for an ideal tibial rotational position.

  15. Cemented or cementless total knee arthroplasty?

    PubMed Central

    Prudhon, Jean-Louis; Verdier, Régis

    2017-01-01

    Introduction: Since 1996 we have been using cementless fixation with hydroxyapatite (HA) coating. The purpose of this paper is to compare survivorship of a series of 100 cemented Total Knee Arthroplasty (TKA) to a similar series of 100 cementless with a follow up of 11–16 years. Material methods: Both TKA are mobile bearing total knee postero-stabilized. They can be used with cement or without cement. Among 1030 New Wave TKATM implanted from 2002 to 2015 we have identified 100 cemented TKAs and 100 cementless TKAs. All these cases were primary replacement. Differences in survival probability were determined using log-rank test. Results: Survival probabilities at 11 years of follow-up were: Cemented group: 90.2% CI95% [81.9–94.8]; Cementless group: 95.4% CI95% [88.1–98.2]. Comparison between both group showed significant difference, p = 0.32. Discussion: The advantages of cementless TKA are bone stock preservation, cement debris protection and the potential to achieve biologic fixation. Cementless implants rely on a porous or roughened surface to facilitate bone formation. HA has been shown to accelerate bone integration and to decrease micro motion of the components and to increase fixation. With a survival probability of 90.2% (cemented version) and 95.4% (cementless version), this total knee prosthesis performs as intended in primary total knee arthroplasty. No statistical differences could be found between cemented and cementless implants. PMID:29232186

  16. Potential Operating Room Fire Hazard of Bone Cement.

    PubMed

    Sibia, Udai S; Connors, Kevin; Dyckman, Sarah; Zahiri, Hamid R; George, Ivan; Park, Adrian E; MacDonald, James H

    Approximately 600 cases of operating room (OR) fires are reported annually. Despite extensive fire safety education and training, complete elimination of OR fires still has not been achieved. Each fire requires an ignition source, a fuel source, and an oxidizer. In this case report, we describe the potential fire hazard of bone cement in the OR. A total knee arthroplasty was performed with a standard medial parapatellar arthrotomy. Tourniquet control was used. After bone cement was applied to the prepared tibial surface, the surgeon used an electrocautery device to resect residual lateral meniscus tissue-and started a fire in the operative field. The surgeon suffocated the fire with a dry towel and prevented injury to the patient. We performed a PubMed search with a cross-reference search for relevant papers and found no case reports outlining bone cement as a potential fire hazard in the OR. To our knowledge, this is the first case report identifying bone cement as a fire hazard. OR fires related to bone cement can be eliminated by correctly assessing the setting time of the cement and avoiding application sites during electrocautery.

  17. Functional performance after tibial rotationplasty.

    PubMed

    Murray, M P; Jacobs, P A; Gore, D R; Gardner, G M; Mollinger, L A

    1985-03-01

    We measured muscle strength, joint motion, and gait parameters and determined the electromyographic activities of the ankle and knee during walking, running, and stair-climbing in two children who had had a tibial rotationplasty for osteosarcoma of the distal end of the femur. Both had marked loss of strength in the plantar flexors on the side of the prosthesis compared with the sound side, although electromyographic recordings showed that the rotated calf muscles, to a substantial degree, had assumed the function of extensors of the prosthetic knee. Despite some abnormalities in gait, both children walked at speeds that were comparable to those of normal children. They could also run, climb stairs by stepping up with both limbs, and participate in many recreational activities. The functional abilities of these children suggested that rotationplasty, in patients with a similar lesion, is a worth-while alternative to above-the-knee amputation.

  18. Asphalt cement poisoning

    MedlinePlus

    ... petroleum material that hardens when it cools. Asphalt cement poisoning occurs when someone swallows asphalt. If hot ... found in: Road paving materials Roofing materials Tile cements Asphalt may also be used for other purposes.

  19. Genetics Home Reference: tibial muscular dystrophy

    MedlinePlus

    ... more common in particular ethnic groups? Genetic Changes Mutations in the TTN gene cause tibial muscular dystrophy . ... in chemical signaling and in assembling new sarcomeres. Mutations in the TTN gene alter the structure and ...

  20. [Retrograde nailing in a tibial fracture].

    PubMed

    Valls-Mellado, M; Martí-Garín, D; Fillat-Gomà, F; Marcano-Fernández, F A; González-Vargas, J A

    2014-01-01

    We describe a case of a severely comminuted type iiia open tibial fracture, with distal loss of bone stock (7 cm), total involvement of the tibial joint surface, and severe instability of the fibular-talar joint. The treatment performed consisted of thorough cleansing, placing a retrograde reamed calcaneal-talar-tibial nail with proximal and distal blockage, as well as a fibular-talar Kirschner nail. Primary closure of the skin was achieved. After 3 weeks, an autologous iliac crest bone graft was performed to fill the bone defect, and the endomedullary nail, which had protruded distally was reimpacted and dynamized distally. The bone defect was eventually consolidated after 16 weeks. Currently, the patient can walk without pain the tibial-astragal arthrodesis is consolidated. Copyright © 2013 SECOT. Published by Elsevier Espana. All rights reserved.

  1. The natural evolution of internal tibial torsion.

    PubMed

    Weiner, D S; Weiner, S D

    1979-11-01

    Faced with a confusing body of literature concerning the necessity for treatment of internal tibial torsion, the authors conducted a retrospective review of 395 consecutive cases of manifest intoeing arising from internal tibial torsion. An additional Group of 200 uninvolved teenagers served as older controls. The conclusion drawn supports an attitude of patience and observation as spontaneous resolution is to be routinely expected by skeletal maturity. Copyright 2013, SLACK Incorporated.

  2. Yield stress of cemented tungsten carbide

    NASA Technical Reports Server (NTRS)

    Ruoff, A. L.; Wanagel, J.

    1975-01-01

    Cemented tungsten carbide yields plastically at room temperature in the presence of a large hydrostatic pressure component. By approximate analysis of the state of stress in supported opposed anvils and by measurement of the pressure at which the anvil tips exhibit a permanent deviation from planarity, we have obtained the yield stress of such materials. Our value for the yield stress of a 3% cobalt cemented tungsten carbide is 86 kbar.

  3. In vitro and in vivo evaluation on the bioactivity of ZnO containing nano-hydroxyapatite/chitosan cement.

    PubMed

    Li, Zhang; Yubao, Li; Yi, Zuo; Lan, Wu; Jansen, John A

    2010-04-01

    A ZnO containing nano-hydroxyapatite/chitosan (n-HA/CS) cement was developed and its bone formation ability was investigated in vitro and in vivo. The physico-chemical properties of the cement were determined in terms of pH variation during and after setting, injectability and wettability. The results indicated that, the pH varied from 7.04 to 7.12 throughout the soaking of the cement in distilled water. The injectability was excellent during the first 4 min, but the cement became less injectable or even not injectable at all after 7 min setting. The static contact angle of the cement against water was 53.5 +/- 2.7 degrees . The results of immersion tests in simulated body fluid (SBF) indicated that the cement exhibited excellent bone-like apatite forming ability. In vivo studies, involving the installation of the cement of tibial-bone defects in rabbit tibia revealed an inflammatory response around the cement at 3 days of implantation. After 4 weeks, the inflammation began to disappear and the cement had bound to the surrounding host bone. Radiological examination also confirmed that the ZnO containing n-HA/CS cement significantly induced new bone formation. These results suggest that the ZnO containing n-HA/CS cement may be beneficial to enhance bone regeneration in osseous defect sites.

  4. Increased lateral tibial posterior slope is related to tibial tunnel widening after primary ACL reconstruction.

    PubMed

    Sabzevari, Soheil; Rahnemai-Azar, Amir Ata; Shaikh, Humza S; Arner, Justin W; Irrgang, James J; Fu, Freddie H

    2017-12-01

    The purpose of the study was to determine the influence of femoral and tibial bone morphology on the amount of femoral and tibial tunnel widening after primary anatomic ACL reconstruction. It was hypothesized that tibial and femoral bone morphology would be significantly correlated with tunnel widening after anatomic ACL reconstruction. Forty-nine consecutive patients (mean age 21.8 ± 8.1 years) who underwent primary single-bundle anatomic ACL reconstruction with hamstring autograft were enrolled. Two blinded observers measured the bone morphology of tibia and femur including, medial and lateral tibial posterior slope, medial and lateral tibial plateau width, medial and lateral femoral condyle width, femoral notch width, and bicondylar width on preoperative magnetic resonance imaging (MRI) scans. Tibial and femoral tunnel width at three points (aperture, mid-section, and exit) were measured on standard anteroposterior radiograph from 1 week and 1 year postoperatively (mean 12.5 ± 2 months). Tunnel width measurements at each point were compared between 1 week and 1 year to calculate percent of tunnel widening over time. Multivariable linear regression was used to analyze correlations between bone morphology and tunnel widening. Increase in lateral tibial posterior slope was the only independent bony morphology characteristics that was significantly correlated with an increased tibial tunnel exit widening (R = 0.58). For every degree increase in lateral tibial posterior slope, a 3.2% increase in tibial tunnel exit width was predicted (p = 0.003). Excellent inter-observer and intra-observer reliability were determined for the measurements (ICC = 0.91 and 0.88, respectively). Increased lateral tibial posterior slope is an important preoperative anatomic factor that may predict tunnel widening at the tibial tunnel exit. In regard to clinical relevance, the results of this study suggest that lateral tibial posterior slope be measured

  5. The complex tibial organ of the New Zealand ground weta: sensory adaptations for vibrational signal detection.

    PubMed

    Strauß, Johannes; Lomas, Kathryn; Field, Laurence H

    2017-05-17

    In orthopteran insects, a complex tibial organ has evolved to detect substrate vibrations and/or airborne sound. Species of New Zealand weta (Anostostomatidae) with tympanal ears on the foreleg tibia use this organ to communicate by sound, while in atympanate species (which communicate by substrate drumming) the organ is unstudied. We investigated the complex tibial organ of the atympanate ground weta, Hemiandrus pallitarsis, for vibration detection adaptations. This system contains four sensory components (subgenual organ, intermediate organ, crista acustica homolog, accessory organ) in all legs, together with up to 90 scolopidial sensilla. Microcomputed tomography shows that the subgenual organ spans the hemolymph channel, with attachments suggesting that hemolymph oscillations displace the organ in a hinged-plate fashion. Subgenual sensilla are likely excited by substrate oscillations transmitted within the leg. Instead of the usual suspension within the middle of the tibial cavity, we show that the intermediate organ and crista acustica homolog comprise a cellular mass broadly attached to the anterior tibial wall. They likely detect cuticular vibrations, and not airborne sound. This atympanate complex tibial organ shows elaborate structural changes suggesting detection of vibrational stimuli by parallel input pathways, thus correlating well with the burrowing lifestyle and communication by substrate-transmitted vibration.

  6. Petroleum Sludge as gypsum replacement in cement plants: Its Impact on Cement Strength

    NASA Astrophysics Data System (ADS)

    Benlamoudi, Ali; Kadir, Aeslina Abdul; Khodja, Mohamed

    2017-08-01

    Due to high cost of cement manufacturing and the huge amount of resources exhaustion, companies are trying to incorporate alternative raw materials or by-products into cement production so as to produce alternative sustainable cement. Petroleum sludge is a dangerous waste that poses serious imparts on soil and groundwater. Given that this sludge contains a high percentage of anhydrite (CaSO4), which is the main component of gypsum (CaSO4.2H2O), it may play the same gypsum role in strength development. In this research, a total replacement of gypsum (100%) has been substituted by petroleum sludge in cement production and has led to an increase of 28.8% in UCS values after 28 curing days. Nevertheless, the burning of this waste has emitted a considerable amount of carbon monoxide (CO) gas that needs to be carefully considered prior to use petroleum sludge within cement plants.

  7. Tibial Bone Density in Athletes With Medial Tibial Stress Syndrome: A Controlled Study

    PubMed Central

    Özgürbüz, Cengizhan; Yüksel, Oğuz; Ergün, Metin; İşlegen, Çetin; Taskiran, Emin; Denerel, Nevzad; Karamizrak, Oğuz

    2011-01-01

    Medial tibial stress syndrome (MTSS) is a common overuse injury of the lower extremity predominantly observed in weight bearing activities. Knowledge about the pathological lesions and their pathophysiology is still limited. Only a single study was found to have investigated tibial bone density in the pain region, revealing lower density in athletes with long standing (range, 5-120 month) MTSS. In a follow-up study, bone density was determined to return to normal levels after recovery. The purpose of the present study was to investigate tibial bone density in athletes with shorter MTSS history (range, 3-10 weeks). A total of 11 athletes (7 males, 4 females) diagnosed with medial tibial stress syndrome were included in the study. The control group consisted of 11 regularly exercising individuals (7 males, 4 females). Tibial, femoral and vertebral bone densities were measured by dual energy x-ray absorptiometry. Total calcium intake was calculated by evaluating detailed nutrition history. No statistically significant differences were found in the tibial, femoral and vertebral bone densities between the groups. No statistically significant difference was found among groups, considering for calcium intake. Tibial bone densities were not lower in athletes with MTSS of 5.0 weeks mean duration (range, 3-10 weeks) compared to the healthy control group. Longitudinal studies with regular tibial bone density measurements in heavily trained athletes are necessary to investigate tibial density alterations in MTSS developing athletes during the course of the symptoms. Key points Tibial, femoral and vertebral bone densities were measured by dual energy x-ray absorptiometry. No differences were found between the MTSS group (MTSS history 3-10 weeks) and the healthy athletes group. PMID:24149568

  8. Radiographic results of an accelerometer-based, handheld surgical navigation system for the tibial resection in total knee arthroplasty.

    PubMed

    Nam, Denis; Cross, Michael; Deshmane, Prashant; Jerabek, Seth; Kang, Michael; Mayman, David J

    2011-10-05

    In total knee arthroplasty (TKA), intramedullary and extramedullary tibial alignment guides are not proven to be highly accurate in obtaining alignment perpendicular to the mechanical axis in the coronal plane. The objective of this study was to determine the accuracy of an accelerometer-based, handheld surgical navigation system in obtaining a postoperative tibial component alignment within 2° of the intraoperative goal in both the coronal and sagittal planes. A total of 151 TKAs were performed by 2 surgeons using a handheld surgical navigation system to perform the tibial resection. Postoperatively, standing anteroposterior hip-to-ankle radiographs and lateral knee-to-ankle radiographs were performed to determine the varus/valgus alignment and the posterior slope of the tibial components relative to the mechanical axis in both the coronal and sagittal planes. Findings showed that 95.3% of the tibial components were placed within 2° of the intraoperative goal in the coronal plane and 96.1% of the components were placed within 2° of the intraoperative goal in the sagittal plane. Overall, mean postoperative lower-extremity alignment was -0.3°±2.1°, with 97% of patients having an alignment within 3° of a neutral mechanical axis. The handheld surgical navigation system improves the accuracy of the tibial resection and subsequent tibial component alignment in TKA. It is able to combine the accuracy of computer-assisted surgery systems with the ease of use and familiarity of conventional, extramedullary alignment systems, and the ability to adjust both the coronal and sagittal alignments intraoperatively may prove clinically useful in TKA. Copyright 2011, SLACK Incorporated.

  9. Masquelet technique with external locking plate for recalcitrant distal tibial nonunion.

    PubMed

    Ma, Ching-Hou; Chiu, Yen-Chun; Tsai, Kun-Ling; Tu, Yuan-Kun; Yen, Cheng-Yo; Wu, Chin-Hsien

    2017-12-01

    In the present retrospective study, we aimed to analyze the results of treatment for recalcitrant distal tibial nonunion using Masquelet technique with locking plate as a definitive external fixator. We included 15 consecutive cases of distal tibial nonunion treated at our hospital between January 2012 and December 2015. The reconstructive procedure comprised debridement of the nonunion site, deformity correction, stabilization with an external locked plate, defect filling with cement spacer for inducing membrane formation, and bone reconstruction using a cancellous bone autograft (Masquelet technique). All patients were followed-up for at least one year. Fracture union occurred in all cases after a median of 6.5 months (range, 5-12 months). Mean ankle motion ranged from 12.3 (range, 5-20) degrees of dorsiflexion to 35 (range, 5-55) degrees of plantar flexion. At the final follow-up, the median Iowa ankle score was 83 (range, 68-91). Eight patients had excellent scores, six had good scores, and one had fail score. Although the current study involved only a small number of patients and the intervention comprised two stages, we consider that the used protocol is a simple and valuable alternative for the treatment of recalcitrant distal tibial nonunion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Vacuum-mixing cement does not decrease overall porosity in cemented femoral stems: AN IN VITRO LABORATORY INVESTIGATION

    PubMed Central

    Messick, K. J.; Miller, M. A.; Damron, L. A.; Race, A.; Clarke, M. T.; Mann, K. A.

    2008-01-01

    The role of vacuum mixing on the reduction of porosity and on the clinical performance of cemented total hip replacements remains uncertain. We have used paired femoral constructs prepared with either hand-mixed or vacuum-mixed cement in a cadaver model which simulated intra-operative conditions during cementing of the femoral component. After the cement had cured, the distribution of its porosity was determined, as was the strength of the cement-stem and cement-bone interfaces. The overall fraction of the pore area was similar for both hand-mixed and vacuum-mixed cement (hand 6%; vacuum 5.7%; paired t-test, p = 0.187). The linear pore fractions at the interfaces were also similar for the two techniques. The pore number-density was much higher for the hand-mixed cement (paired t-test, p = 0.0013). The strength of the cement-stem interface was greater with the hand-mixed cement (paired t-test, p = 0.0005), while the strength of the cement-bone interface was not affected by the conditions of mixing (paired t-test, p = 0.275). The reduction in porosity with vacuum mixing did not affect the porosity of the mantle, but the distribution of the porosity can be affected by the technique of mixing used. PMID:17785755

  11. Treatment of tibial diaphyseal fractures following plateless tibial tuberosity advancement to manage cranial cruciate disease.

    PubMed

    De Sousa, R; Egan, P; Parsons, K; Butterworth, S; Calvo, I; Roch, S; Moores, A P

    2017-07-01

    To report diaphyseal fractures of the proximal tibia following tibial tuberosity advancement without plate stabilisation for the management of cranial cruciate ligament rupture in dogs. Members of the British Veterinary Orthopaedic Association's online discussion forum were invited to submit revision cases of tibial diaphyseal fracture following tibial tuberosity advancement without plate fixation. Data collected included signalment, surgical revision technique, pre- and postoperative revision radiographic findings, complications and veterinary assessment. Owners were invited to complete the Liverpool Osteoarthritis in Dogs questionnaire. A total of 17 dogs were included in the study. Eleven dogs had OrthoFoam-wedge modified Maquet procedures and six had the tibial tuberosity advancement rapid procedure. Tibial tuberosity advancement was maintained in 14/17 cases. Postrevision surgery complications occurred in eight cases: minor complications in 3/17 dogs; major in 5/17 and no catastrophic complications. Surgical site infection was the most common complication (4/8). Final clinical outcome found 8/17 of dogs to have excellent, 8/17 satisfactory and 1/17 poor clinical outcome. The median Liverpool Osteoarthritis in Dogs score was 12/52 (range 2 to 28). Final outcome was 6/13 owners that were very satisfied, 2/13 owners indifferent and 5/13 owners very disappointed. This is the first case series reporting tibial diaphyseal fractures following tibial tuberosity advancement without plate stabilisation. The authors report here a wide spectrum of potential fixation strategies should one of these fractures occur. © 2017 British Small Animal Veterinary Association.

  12. Inexpensive bone cement substitute for vertebral cement augmentation training.

    PubMed

    Hollensteiner, Marianne; Samrykit, Markus; Hess, Michael; Fuerst, David; Esterer, Benjamin; Schrempf, Andreas

    2016-08-01

    Vertebral compression fractures are treated surgically for approximately 25 years. In percutaneous cement augmentation techniques bone cement is applied to a fractured vertebra under fluoroscopic evidence to stabilize the bone fragments. Complications due to leakage of the low viscosity bone cement are reported in 5 to 15% of all routine cases. During the intraoperative application of bone cement surgeons rely on visiohaptic feedback and hence need to be familiar with the cement's rheology properties. Therefore, training is necessary. A hybrid simulator for cement augmentation training was developed but the usage of expensive real cement limits its purpose as a training modality. Twentythree inexpensive bone substitutes were developed and tested with the objective to mimic real bone cement. Cement application measurements were conducted and a mathematical model of the measurement setup was created. Compared with real bone cement, a cement substitute based on Technovit 3040 in combination with radical catchers and additional additives was identified as an appropriate substitute for cement augmentation training.

  13. Calf muscle wasting after tibial shaft fracture

    PubMed Central

    Khalid, M; Brannigan, A; Burke, T

    2006-01-01

    Objectives To study the long term effect of tibial shaft fractures treated by immobilisation in a long leg cast on the calf muscle bulk. Methods Computed tomography scans were performed at fixed points on the lower legs of 23 non‐professional athletes who sustained closed tibial fractures 16 years previously. Length of immobilisation was determined from the hospital records. All the fractures were treated non‐operatively. The cross sectional area of the various leg compartments was measured and compared with the non‐injured leg. Results There was a significant reduction in cross sectional area of the posterior compartment (p<0.001, Student's t test). No such difference was seen in the anterolateral compartment. Conclusion Tibial fractures treated non‐operatively are associated with significant long term calf muscle wasting. PMID:16720890

  14. 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

  15. Do Capactively Coupled Electric Fields Accelerate Tibial Stress Fracture Healing

    DTIC Science & Technology

    2005-12-01

    medial tibial condylar stress fractures were investigated. Four imaging...Capacitively coupled electric fields did not accelerate tibial stress fracture healing of the group as a whole in comparison with placebo treatment (rest...but women took longer to recover from tibial stress fractures than men. Superior treatment compliance was positively associated with reduced time to healing. REFERENCES NA APPENDICES NA

  16. 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.

  17. 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…

  18. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2003-01-31

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries. DOE joined the Materials Management Service (MMS)-sponsored joint industry project ''Long-Term Integrity of Deepwater Cement under Stress/Compaction Conditions.'' Results of the project contained in two progress reports are also presented in this report.

  19. Insufficiency fractures of the tibial plateau

    SciTech Connect

    Manco, L.G.; Schneider, R.; Pavlov, H.

    1983-06-01

    An insufficiency fracture of the tibial plateau may be the cause of knee pain in patients with osteoporosis. The diagnosis is usually not suspected until a bone scan is done, as initial radiographs are often negative or inconclusive and clinical findings are nonspecific and may simulate osteoarthritis or spontaneous osteonecrosis. In five of 165 patients referred for bone scans due to nontraumatic knee pain, a characteristic pattern of intense augmented uptake of radionuclide confined to the tibial plateau led to a presumptive diagnosis of insufficiency fracture, later confirmed on radiographs.

  20. Fracture of tibial tuberosity in an adult

    PubMed Central

    Albuquerque, Rodrigo Pires e; Campos, André Siqueira; de Araújo, Gabriel Costa Serrão; Gameiro, Vinícius Schott

    2013-01-01

    The fracture of tibial tuberosity is a rare lesion and still more unusual in adults. We describe a case in an adult who suffered a left knee injury due to a fall from height. No risk factors were identified. The lesion was treated with surgical reduction and internal fixation. The rehabilitation method was successful, resulting in excellent function and rage of motion of the knee. The aim of this study was to present an unusual case of direct trauma of the tibial tuberosity in an adult and the therapy performed. PMID:24293543

  1. Nanocrystalline tetracalcium phosphate cement.

    PubMed

    Gbureck, U; Barralet, J E; Hofmann, M P; Thulí, R

    2004-05-01

    Calcium hydroxide cements can lack long-term stability and achieve sustained release by matrix-controlled diffusion of hydroxyl ions. Tetracalcium phosphate (TTCP) hydrolyzes slowly to form calcium hydroxide and a thin insoluble apatite layer that prevents further reaction. In this study, mechanical amorphization was used to create a setting calcium-hydroxide-releasing cement from TTCP. The effect of high-energy ball milling of TTCP on the mechanical properties of the cement was investigated. X-ray diffraction data were used to determine the phase composition of the set cements. An accelerated in vitro test compared pH of water after prolonged boiling of nanocrystalline TTCP cements and a calcium salicylate material. As milling time increased, cement compressive strength and degree of conversion increased. Hydroxyl ion release from the cement was comparable with that from a calcium salicylate material. This new cement system offers the antimicrobial potential of calcium salicylate materials combined with the long-term stability of insoluble apatite cements.

  2. Dental polyelectrolyte cements. III. Effect of additives on their rheology.

    PubMed

    Cook, W D

    1983-04-01

    As part of a series of investigations of dental polyelectrolyte cements, the influence of additives was studied by viscometry. At low concentrations, tartaric acid was found to exert an accelerating influence on glass ionomer cements but to retard the reaction by complex formation at high concentrations. When dissolved with the liquid component, NaF accelerated some glass ionomer cements and retarded others. NaCl was found to accelerate the zinc polycarboxylate cements, possibly through its reduction in the electrical potential between powder and liquid phases. Neutralization of the polyacids retarded the reactions but not enough to indicate that hydrogen ions were directly involved in the rate determining step.

  3. Association between body weight and proximal tibial bone mineral density after bilateral total knee arthroplasty.

    PubMed

    Ishii, Yoshinori; Noguchi, Hideo; Sato, Junko; Ishii, Hana; Todoroki, Koji; Toyabe, Shin-Ichi

    2017-10-01

    Proximal tibial bone mineral density (BMD) has been studied for its potential impact on subsidence and loosening of the tibial component after total knee arthroplasty (TKA). However, no known studies of proximal tibial BMD after TKA have evaluated the effect of major impact factors such as body weight (BW), muscle strength, and level of activity. We aim to determine whether factors such as level of activity, quadriceps strength, BW, gender, age, and prosthetic design affect proximal tibial BMD over the mid- to long-term following TKA. We evaluated 36 patients (72 knees) who were undergoing bilateral TKA performed by a single surgeon. Median follow up time was 115months (range, 60-211months) for a minimum of five years. We measured BMD in the proximal tibia and used a hand-held dynamometer to measure quadriceps isometric strength, recording the maximum value of three measurements for each patient. Univariate analyses using Spearman's correlation coefficient for continuous variables revealed a weak negative correlation between age and BMD (r=-0.316, P=0.007) and a moderate positive correlation between BW and BMD (r=0.430, P<0.001). However, no significant correlations were found between the other factors above and BMD for continuous and discrete variables. Based on multivariate analyses, only BW had a significant effect on BMD (β=0.342, P=0.003). BW is the most impact factor on the proximal tibial BMD after mid- to long-term follow up TKA. Therefore, the management of BW may contribute to prevention of decline of tibial BMD for TKA patients owing to aging. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Feasibility and Safety of a Cemented PEEK-on-PE Knee Replacement in a Goat Model: A Preliminary Study.

    PubMed

    Du, Zhe; Zhu, Zhonglin; Yue, Bing; Li, Zhanchun; Wang, You

    2018-02-13

    Polyether-ether-ketone (PEEK) is a potential alternative to metal alloys for use in the orthopedic implants; however, an in vivo study in an appropriate animal model is essential and has not yet been initiated. The aim of the present study was to gather some preliminary evidence regarding the performance and safety of a cemented PEEK-based knee replacement device in a goat model. Fifteen adult goats were randomly divided into two groups; the control group (n = 5), which received a sham operation, and the experimental group (n = 10), which received a total knee arthroplasty with a PEEK-based knee replacement device. The animals were sacrificed at 12 (control n = 5; experimental n = 5) or 24 weeks (experimental n = 5). Blood parameter measurements and radiographs of the knee joints were obtained. The synovium and main organs were removed and histologically assessed. The knee joints with the prosthesis were analyzed via micro-computed tomography and laser confocal microscopy. There was no occurrence of implant fracture or prosthesis sinking during the 24 weeks of radiological observations, except for one case of prosthesis dislocation at 4 weeks. There was a 6% decrease in femoral bone density (BD) at 12 weeks, but no further decrease by 24 weeks. No changes in BD were observed in the tibial ends. The bulk implant was biocompatible in terms of histological analysis of the local synovium and organs. There were no optical scratches on the surface of the retrieved components; the femoral component surface was rougher, while the tibial insert was smoother after 24 weeks. The novel PEEK-based knee replacement device in a goat model was feasible and safe; however, prior to use in humans, further studies concerning PEEK high load-bearing implant designs should be carried out to expand on our results. © 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  5. 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.

  6. Medial tibial stress syndrome: case report.

    PubMed

    Jovicić, Milica; Jovicić, Vladimir; Hrković, Marija; Lazović, Milica

    2014-01-01

    Although it can be difficult to differentiate pain in lower legs, it is important for clinicians to differentiate medial tibial stress syndrome, which is a rather benign condition, from acute compartment syndrome, which is an emergency, as well as from different types of stress fractures described in this region. The aim of this case report was to present medial tibial stress syndrome as a clinical diagnosis, possible dilemmas in differential diagnosis and the efficacy of rehabilitation treatment. A 25-year old male patient sought medical help complaining of the pain along the distal third of tibia. The pain was present on palpation of the distal two-thirds of the lateral and medial tibial border over the length of 9 cm and on muscle manual testing of foot flexors. The patient underwent physical and exercise treatment for three weeks. The recovery was monitored by visual analogue scale, which measured the lower leg pain, pain on palpation and manual muscle testing. In addition, the patient himself assessed his ability to resume sport activities on the 5-point Likert scale. The final evaluation and measurements showed his complete functional recovery. The results obtained in this case show the importance of accurate clinical diagnosis and rehabilitation for medial tibial stress syndrome.

  7. Research of magnesium phosphosilicate cement

    NASA Astrophysics Data System (ADS)

    Ding, Zhu

    Magnesium phosphosilicate cement (MPSC) is a novel phosphate bonded cement, which consists mainly of magnesia, phosphate and silicate minerals. The traditional magnesium phosphate cements (MPCs) usually composed by ammonium phosphate, and gaseous ammonia will emit during mixing and in service. There is no noxious ammonia released from MPSC, furthermore, it can recycle a large volume of the non-hazardous waste. The goal of this research is to investigate the composition, reaction products, reaction mechanism, microstructure, properties, durability and applications of the MPSC. MPSC sets rapidly and has high early strength. It reacts better with solid industrial waste when compared to Portland cement. Many solid industrial wastes, such as fly ash, steel slag, coal gangue, red coal gangue, red mud, barium-bearing slag, copper slag, silica fume, and ground granulated blast furnace slag, have been used as the main component (40% by weight) in MPSC. The research has found that these aluminosilicate (or ironsilicate, or calciumsilicate) minerals with an amorphous or glass structure can enhance the performance of MPSC. The disorganized internal structure of amorphous materials may make it possess higher reactivity compared to the crystalline phases. Chemical reaction between phosphate and these minerals may form an amorphous gel, which is favorable to the cementing. Borax, boric acid and sodium tripolyphosphate have been used as retardants in the MPSC system. It is found that boric acid has a higher retarding effect on the setting of cement, than borax does. However, sodium polyphosphate accelerates the reaction of MPSC. The hydration of MPSC is exothermic reaction. The heat evolution may prompt hydrates formation, and shorten the setting process. Modern materials characterization techniques, XRD, DSC, TG-DTA FTIR, XPS, MAS-NMR, SEM, TEM, MIP, etc. were used to analyze the phase composition, micro morphology, and microstructure of hardened MPSC. The main hydration product

  8. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2004-01-30

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries.

  9. Reverse Segond Fracture Associated with Anteromedial Tibial Rim and Tibial Attachment of Anterior Cruciate Ligament Avulsion Fractures

    PubMed Central

    2017-01-01

    Reverse Segond fracture is an uncommon avulsion fracture of the tibial attachment of the deep portion of the medial collateral ligament of the knee. We report a reverse Segond fracture associated with anterior cruciate ligament tibial avulsion fracture and anteromedial tibial rim fracture. Unlike previous reports, the combination of reverse Segond fracture, anteromedial tibial rim fracture, and anterior cruciate ligament avulsion fracture was not associated with posterior cruciate ligament injury, posterolateral corner injury, or tibial plateau fracture. This new combination of injuries provides better understanding of the mechanisms of ligamentous injuries of the knee and highlights the importance of meticulous assessment of these injuries for accurate diagnosis and subsequent management. PMID:28951794

  10. Cemented Volcanic Soils, Martian Spectra and Implications for the Martian Climate

    NASA Technical Reports Server (NTRS)

    Bishop, J. L.; Schiffman, P.; Drief, A.; Southard, R. J.

    2004-01-01

    Cemented soils formed via reactions with salts are studied here and provide information about the climate when they formed. Spectroscopic and microprobe studies have been performed on cemented volcanic crusts in order to learn about the composition of these materials, how they formed, and what they can tell us about climatic interactions with surface material on Mars to form cemented soils. These crusts include carbonate, sulfate and opaline components that may all be present in cemented soil units on Mars.

  11. Piezoelectric and bonding properties of a cement-based composite for dental application

    NASA Astrophysics Data System (ADS)

    Wang, Qi; Liu, Jinsong; Zhu, Jianguo; Ye, Yongmei; Li, Xiang; Chen, Zhiqing

    2008-11-01

    A cement-based piezoelectric composite was introduced as real-time health monitoring systems to dentin. Lithium sodium potassium niobate and zinc polycarboxylate cement were mixed and made piezoelectric under different poling conditions. X-ray diffraction and scanning electron microscope confirmed the component and microstructure of the cement. The bonding force of the composites was compared to that of pure cement by analysis of variance. The optimum poling method was determined and the influencing factors of piezoelectric coefficient were discussed.

  12. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2002-01-23

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems: foamed and sodium silicate slurries. Comparison studies of the three cement systems examined several properties: tensile strength, Young's modulus, water permeability, and shear bond. Testing was also done to determine the effect that temperature cycling has on the shear bond properties of the cement systems. In addition, analysis was carried out to examine alkali silica reactivity of slurries containing ULHS. Data is also presented from a study investigating the effects of mixing and pump circulation on breakage of ULHS. Information is also presented about the field application of ULHS in cementing a 7-in. intermediate casing in south Texas.

  13. [Temporary articulating spacer with antibiotic-impregnated cement for an infected knee endoprosthesis].

    PubMed

    Pietsch, M; Wenisch, C; Traussnig, S; Trnoska, R; Hofmann, S

    2003-06-01

    Two-stage reimplantation remains the gold standard in the treatment of late infected total knee arthroplasties. The reported disadvantages include difficult exposure at the time of reimplantation and less functional outcome by using static spacers. Patients who receive an articulating spacer retain a functional joint before second-stage reimplantation. This may reduce the disadvantages of static spacers (ligament contracture, extensor lag, arthrofibrosis). There is no difference in the success rates of eradicating infection (range: 90-96%). In a prospective study 24 consecutive patients were treated with an articulating spacer. The articulating spacer is made by cleaning and autoclaving the removed femoral component and the tibial polyethylene insert. These are reinserted during the same operation with antibiotic-loaded cement. The average time during which the spacer was in place was 16 weeks (range: 7-28 weeks). During an average follow-up period of 14.8 months (range: 5-33 months) one patient had a secondary reinfection. Use of an articulating spacer is economical and decreases the risk of complications in reimplantation with good functional outcome.

  14. A novel injectable borate bioactive glass cement for local delivery of vancomycin to cure osteomyelitis and regenerate bone.

    PubMed

    Cui, Xu; Zhao, Cunju; Gu, Yifei; Li, Le; Wang, Hui; Huang, Wenhai; Zhou, Nai; Wang, Deping; Zhu, Yi; Xu, Jun; Luo, Shihua; Zhang, Changqing; Rahaman, Mohamed N

    2014-03-01

    Osteomyelitis (bone infection) is often difficult to cure. The commonly-used treatment of surgical debridement to remove the infected bone combined with prolonged systemic and local antibiotic treatment has limitations. In the present study, an injectable borate bioactive glass cement was developed as a carrier for the antibiotic vancomycin, characterized in vitro, and evaluated for its capacity to cure osteomyelitis in a rabbit tibial model. The cement (initial setting time = 5.8 ± 0.6 min; compressive strength = 25.6 ± 0.3 MPa) released vancomycin over ~25 days in phosphate-buffered saline, during which time the borate glass converted to hydroxyapatite (HA). When implanted in rabbit tibial defects infected with methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis, the vancomycin-loaded cement converted to HA and supported new bone formation in the defects within 8 weeks. Osteomyelitis was cured in 87 % of the defects implanted with the vancomycin-loaded borate glass cement, compared to 71 % for the defects implanted with vancomycin-loaded calcium sulfate cement. The injectable borate bioactive glass cement developed in this study is a promising treatment for curing osteomyelitis and for regenerating bone in the defects following cure of the infection.

  15. High tibial slope correlates with increased posterior tibial translation in healthy knees.

    PubMed

    Schatka, Imke; Weiler, Andreas; Jung, Tobias M; Walter, Thula C; Gwinner, Clemens

    2017-09-09

    Notwithstanding the importance of the tibial slope (TS) for anterior tibial translation, little information is available regarding the implications on posterior laxity, particularly in healthy subjects. It was hypothesized that increased TS is associated with decreased posterior tibial translation (PTT) in healthy knees. A total of 124 stress radiographs of healthy knees were enrolled in this study. Tibial slope and the posterior tibial translation were evaluated using a Telos device with a 150-N force at 90° of knee flexion. Two blinded observers reviewed independently on two different occasions. One hundred and twenty-four patients [35 females and 89 males; 41 (range 18-75) years] were enrolled in this study, with a mean PTT of 2.8 mm (±1.9 mm; range 0-8 mm) and a mean TS of 8.6° (±2.6°; range 1°-14°). Pearson correlation showed a significant correlation between the PTT and TS in the overall patient cohort (P < 0.0001) with r = 0.76 and R 2  = 0.58. There was no statistical difference between female and male patients regarding the PTT or the TS. Subgrouping of the patient cohort (four groups with n = 31) according to their TS (groups I < 7°; II = 7°-8.5°; III = 9°-10.5°; IV ≥ 11°) revealed significant differences between each subgroup, respectively. Furthermore, there was a weak but significant correlation between age and PTT (P = 0.004, r = 0.26). In addition to the substantial variance in tibial slope and posterior laxity among healthy knees, high tibial slope significantly correlates with increased posterior tibial translation. Increasing age is further associated with a greater magnitude of posterior tibial translation. Consequently, knowledge of the tibial slope facilitates simple estimation of posterior knee laxity, which is mandatory for PCL reconstruction and knee arthroplasty.

  16. 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.

  17. Rheological enhancement of mechanically activated alpha-tricalcium phosphate cements.

    PubMed

    Gbureck, U; Spatz, K; Thull, R; Barralet, J E

    2005-04-01

    Most biocements are two- or three-component acid-based systems with large differences in the component particle sizes, which occurs by virtue of the differing processing routes. This work aimed to improve injectability and strength of a single reactive component cement, that is, mechanically activated alpha-tricalcium phosphate (TCP)-based cement by adding 13-33 wt % of several fine-particle-sized (d(50) of 0.5-1.1 microm) fillers [dicalcium phosphate anhydrous (DCPA), titanium dioxide (TiO(2)), and calcium carbonate] to the monomodal alpha-TCP matrix (d(50) = 9.8 microm). A high zeta-potential was measured for all particles in trisodium citrate solution. The fraction of alpha-TCP cement "injected" through an 800-microm hypodermic needle was found to be only 35% at a powder-to-liquid ratio of 3.5 g/mL. In contrast, the use of fillers decreased cement viscosity to a point, where complete injectability could be obtained. Mechanistically, these additives disrupted alpha-TCP particle packing yet decreased the interparticle spacing by a factor of approximately 5.5 such that the electrostatic repulsion effect was enhanced. A strength improvement was found when DCPA and TiO(2) were used as fillers despite the lower degree of conversion of these cements. Compressive strengths of precompacted cement samples increased from 70 MPa for unfilled alpha-TCP cement to 140 (110) MPa for 23 wt % DCPA (or TiO(2)) fillers as a result of porosity reduction. Strength improvement for more clinically relevant uncompacted cements was achieved by higher powder-to-liquid ratio mixes for filled cements such that maximum strengths of 90 MPa were obtained for 23 wt % DCPA filler compared with 50 MPa for single-component alpha-TCP cement. (c) 2004 Wiley Periodicals, Inc.

  18. Influence of tibial rotation in total knee arthroplasty on knee kinematics and retropatellar pressure: an in vitro study.

    PubMed

    Steinbrück, Arnd; Schröder, Christian; Woiczinski, Matthias; Müller, Tatjana; Müller, Peter E; Jansson, Volkmar; Fottner, Andreas

    2016-08-01

    Although continuous improvements have been made, there is still a considerable amount of unsatisfied patients after total knee arthroplasty (TKA). A main reason for this high percentage is anterior knee pain, which is supposed to be provoked by post-operative increased retropatellar peak pressure. Since rotational malalignment of the implant is believed to contribute to post-operative pain, the aim of this study was to examine the influence of tibial component rotation on knee kinematics and retropatellar pressure. Eight fresh-frozen knee specimens were tested in a weight-bearing knee rig after fixed-bearing TKA under a loaded squat from 20° to 120° of flexion. To examine tibial components with different rotations, special inlays with 3° internal rotation and 3° external rotation were produced and retropatellar pressure distribution was measured with a pressure-sensitive film. The kinematics of the patella and the femorotibial joint were recorded with an ultrasonic-based motion analysis system. Retropatellar peak pressure decreased significantly from 3° internal rotation to neutral position and 3° external rotation of the tibial component (8.5 ± 2.3 vs. 8.2 ± 2.4 vs. 7.8 ± 2.5 MPa). Regarding knee kinematics femorotibial rotation and anterior-posterior translation, patella rotation and tilt were altered significantly, but relative changes remained minimal. Changing tibial rotation revealed a high in vitro influence on retropatellar peak pressure. We recommend the rotational alignment of the tibial component to the medial third of the tibial tuberosity or even more externally beyond that point to avoid anterior knee pain after TKA.

  19. Cement and concrete

    NASA Technical Reports Server (NTRS)

    Corley, Gene; Haskin, Larry A.

    1992-01-01

    To produce lunar cement, high-temperature processing will be required. It may be possible to make calcium-rich silicate and aluminate for cement by solar heating of lunar pyroxene and feldspar, or chemical treatment may be required to enrich the calcium and aluminum in lunar soil. The effects of magnesium and ferrous iron present in the starting materials and products would need to be evaluated. So would the problems of grinding to produce cement, mixing, forming in vacuo and low gravity, and minimizing water loss.

  20. Abyssal seep site cementation: west Florida escarpment

    SciTech Connect

    Neumann, A.C.; Paull, C.K.; Commeau, R.

    1988-02-01

    The deepest submarine cements known so far occur along the 3300-m deep base of the Florida escarpment and are associated with methane-bearing brine seeps, which emanate there. These deep Holocene carbonates, which occur as surficial and buried crusts, burrow fillings, and friable horizons, were sampled via ALVIN. The carbonates form irregular halos extending up to 20 m from seeps colonized by chemosynthetic fauna. Mussels, gastropods, and clams, the carbonate components of the community, produce a shell hash that is locally cemented by coarsely crystalline low-Mg calcite. Halos of palisade calcite are reminiscent of ancient examples of marine cements. Also presentmore » are carbonate hemipelagics cemented by micrite into crusts and burrow fillings. The degree of cementation varies from pervasive to light. Slabs of cemented crust up to 30 cm thick contrast with typical shallow crusts and exhibit irregular tops and smooth bottoms indicating different chemical gradients and pathways. Bulk /delta//sup 13/C values of the carbonates are low, ranging from /minus/ 2.4 to /minus/ 48.5 /per thousand/ (PDB) and implicating as the carbonate source the biogenic methane that occurs in high concentrations at the seeps. The interaction of methane and sulfate in these cement reactions is still unclear. The presence of course mollusk-fragment hardgrounds overlying an eroded limestone and covered by hemipelagics, if encountered elsewhere, could be mistaken for a much shallower setting. The erosion of limestone scarps and the concurrent development of deep hardgrounds containing a fossil chemosynthetic fauna at the unconformity is a scenario that needs to be included in the growing list of limestone facies interpretations.« less

  1. Tibial tubercle torsion, a new factor of patellar instability.

    PubMed

    Chassaing, V; Zeitoun, J-M; Camara, M; Blin, J-L; Marque, S; Chancelier, M-D

    2017-12-01

    External torsion of the anterior tibial tubercle (TT), defined as external rotation around a craniocaudal axis with respect to the posterior femoral condylar plane, may induce patellar instability. To our knowledge no studies have focused on this parameter. The present study aimed to perform an MRI analysis of TT torsion. The study hypothesis was that TT torsion correlates with patellar instability and with 3 of its components: tibial tubercle-trochlear groove (TT-TG) distance, axial engagement index of the patella (AEI), and patellar tilt. Four observers performed MRI measurements for 2 groups: 37 patellar instability patients (PI group) with history of at least 2 patellar dislocations, and 50 control patients with meniscal lesion but free from patellofemoral pathology. All measurements were taken from 2 axial slices with the posterior condylar plane as reference. The intra-class correlation coefficient (ICC) was 0.88. TT torsion correlated with patellar instability, with a mean 5.8̊ in controls and 17.9̊ in the PI group (P<0.001). There were also excellent correlations between TT torsion and TT-TG distance, patellar tilt and patellar lateralization (measured by AEI), with correlation coefficients greater than 0.85. TT torsion is a reproducible measurement, with excellent ICC. It is significantly correlated with patellar instability, with a discrimination threshold of 11.5̊, and correlations with all 3 components of instability. These statistical correlations enable TT torsion to be added to the list of patellar instability factors. Further studies should determine its biomechanical role and assess the contribution of associating TT derotation to medialization or distalization procedures. III; case-control study. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  2. Intraneural ganglion cyst of the tibial nerve.

    PubMed

    Adn, M; Hamlat, A; Morandi, X; Guegan, Y

    2006-08-01

    Intraneural ganglion cyst of the tibial nerve is very rare. To date, only 5 cases of this entity in the popliteal fossa have been reported. We report a new case and review the previously reported cases. A 40-year-old man experienced a mild vague pain in the medial half of his right foot for 3 years. Magnetic resonance imaging scan demonstrated a soft-tissue mass along the right tibial nerve. At surgery, an intraneural ganglion cyst was evacuated. After 12 months, the patient was pain-free with no signs of recurrence. Trauma might be a contributing factor to the development of intraneural ganglion cysts. Application of microsurgical techniques is encouraged.

  3. [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.

  4. Biomechanical Factors in Tibial Stress Fractures

    DTIC Science & Technology

    2005-08-01

    OF TIBIAL STRESS FRACTURE? To be presented at the International Society of Biomechanics Annual Meeting, Cleveland, OH. 3. IS DYNAMIC HIP AND KNEE ...A Radiographic Analysis of the Relationship between the Size and Shape of the Intercondylar Notch and Anterior Cruciate Ligament Injury Knee surgery...Frontal Plane Mechanics during Walking between Patients with Medial and Lateral Knee Presented at the American American Society of Biomechanics Mtg

  5. Tibial Bowing and Pseudarthrosis in Neurofibromatosis Type 1

    DTIC Science & Technology

    2014-04-01

    individuals with tibial bowing had decreases in speed-of- sound z-scores in the bowed tibia compared to the affected tibia. In addition, we were able to...spreadsheets by the research coordinator. c. Biannual phone interviews with individuals with tibial bowing enrolled in Specific Aim 1. -We have...performed biannual phone interviews for individuals with tibial bowing who have reached their required time for phone interviews. In addition we have

  6. Antibacterial effects of conventional glass ionomer cement.

    PubMed

    Dimkov, A; Gjorgievska, E; Nicholson, J W; Kaftandzieva, A

    2016-01-01

    The antibacterial activity of conventional glass ionomer cement against three different microorganism strains alone and following incorporation of 1, 2 and 3% Benzalkonium Chloride and Cetylpyridinium Chloride was evaluated. Agar diffusion method was used to determine the inhibitory effect of the conventional glass ionomer cement ChemFlex on Streptococcus mutans, Lactobacillus casei and Actinomyces viscosus. Bacterial strains were inoculated into BHIB, and incubated in an anaerobic atmosphere (37 °C). From the bacteria grown in the liquid medium, the density of the inoculum was set to be equivalent to McFarland 2 standard. In Shaedler agar, 350 μL of the bacterial suspension were equally spread. Specimens (4 mm × 6 mm) were prepared from the cement without and with addition of 1, 2 and 3% Benzalkonium Chloride and Cetylpyridinium Chloride. The inhibition zones were determined after 48 hours, after 2, 7 and 21 days of incubation. The combination ChemFlex + Benzalkonium Chloride has the best effect on the three analysed bacteria. The Benzalkonium Chloride antibacterial compound has a stronger antibacterial effect than Cetylpyridinium Chloride. Glass ionomer cements can potentially be used as a medium for slow release of active antimicrobial components, and they have the potential to improve clinical outcomes of the cements (Tab. 3, Fig. 3, Ref. 31).

  7. Alternative Fuel for Portland Cement Processing

    SciTech Connect

    Schindler, Anton K; Duke, Steve R; Burch, Thomas E; Davis, Edward W; Zee, Ralph H; Bransby, David I; Hopkins, Carla; Thompson, Rutherford L; Duan, Jingran; Venkatasubramanian, Vignesh; Stephen, Giles

    2012-06-30

    The production of cement involves a combination of numerous raw materials, strictly monitored system processes, and temperatures on the order of 1500 °C. Immense quantities of fuel are required for the production of cement. Traditionally, energy from fossil fuels was solely relied upon for the production of cement. The overarching project objective is to evaluate the use of alternative fuels to lessen the dependence on non-renewable resources to produce portland cement. The key objective of using alternative fuels is to continue to produce high-quality cement while decreasing the use of non-renewable fuels and minimizing the impact on the environment. Burn characteristics and thermodynamic parameters were evaluated with a laboratory burn simulator under conditions that mimic those in the preheater where the fuels are brought into a cement plant. A drop-tube furnace and visualization method were developed that show potential for evaluating time- and space-resolved temperature distributions for fuel solid particles and liquid droplets undergoing combustion in various combustion atmospheres. Downdraft gasification has been explored as a means to extract chemical energy from poultry litter while limiting the throughput of potentially deleterious components with regards to use in firing a cement kiln. Results have shown that the clinkering is temperature independent, at least within the controllable temperature range. Limestone also had only a slight effect on the fusion when used to coat the pellets. However, limestone addition did display some promise in regards to chlorine capture, as ash analyses showed chlorine concentrations of more than four times greater in the limestone infused ash as compared to raw poultry litter. A reliable and convenient sampling procedure was developed to estimate the combustion quality of broiler litter that is the best compromise between convenience and reliability by means of statistical analysis. Multi-day trial burns were conducted

  8. Alternative Fuel for Portland Cement Processing

    SciTech Connect

    Schindler, Anton K; Duke, Steve R; Burch, Thomas E

    2012-06-30

    The production of cement involves a combination of numerous raw materials, strictly monitored system processes, and temperatures on the order of 1500 °C. Immense quantities of fuel are required for the production of cement. Traditionally, energy from fossil fuels was solely relied upon for the production of cement. The overarching project objective is to evaluate the use of alternative fuels to lessen the dependence on non-renewable resources to produce portland cement. The key objective of using alternative fuels is to continue to produce high-quality cement while decreasing the use of non-renewable fuels and minimizing the impact on the environment. Burnmore » characteristics and thermodynamic parameters were evaluated with a laboratory burn simulator under conditions that mimic those in the preheater where the fuels are brought into a cement plant. A drop-tube furnace and visualization method were developed that show potential for evaluating time- and space-resolved temperature distributions for fuel solid particles and liquid droplets undergoing combustion in various combustion atmospheres. Downdraft gasification has been explored as a means to extract chemical energy from poultry litter while limiting the throughput of potentially deleterious components with regards to use in firing a cement kiln. Results have shown that the clinkering is temperature independent, at least within the controllable temperature range. Limestone also had only a slight effect on the fusion when used to coat the pellets. However, limestone addition did display some promise in regards to chlorine capture, as ash analyses showed chlorine concentrations of more than four times greater in the limestone infused ash as compared to raw poultry litter. A reliable and convenient sampling procedure was developed to estimate the combustion quality of broiler litter that is the best compromise between convenience and reliability by means of statistical analysis. Multi-day trial burns were

  9. Tibial shaft fractures in football players.

    PubMed

    Chang, Winston R; Kapasi, Zain; Daisley, Susan; Leach, William J

    2007-06-13

    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. 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. 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.

  10. 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.

  11. A retrospective study of tibial plateau translation following tibial plateau levelling osteotomy stabilisation using three different plate types.

    PubMed

    Woodbridge, N; Corr, S A; Grierson, J; Arthurs, G

    2011-01-01

    To retrospectively evaluate mediolateral translation of the proximal tibial segment (tibial plateau) after tibial plateau levelling osteotomy (TPLO), stabilised with three types of plate. Pre- and postoperative radiographs of 79 dogs that had TPLO surgery using three different types of plates were reviewed. Two plate types incorporated non-locking screws: Slocum (22 cases) and Orthomed Delta (33 cases) plates. The third plate type incorporated locking screws: Synthes TPLO Locking Compression Plate (LCP) (24 cases). The radiographs were viewed by three Diplomate surgeons who were blinded to the type of implant used. Medial or lateral translation of the proximal tibial plateau relative to the tibial diaphysis was assessed and measured at the lateral tibial cortex at the osteotomy site. Mean lateral translation of the tibial plateau was significantly greater when using the Synthes TPLO LCP with locking screws (+2.1 mm) compared to the non-locking Slocum (+0.4 mm) or Orthomed Delta (0.0 mm) plates. The use of the Synthes TPLO LCP will maintain a malalignment of the tibial plateau. Accurate alignment of the tibial plateau must be ensured prior to application of the Synthes TPLO LCP.

  12. Influence of dunite mineral additive on strength of cement

    NASA Astrophysics Data System (ADS)

    Vasilyeva, A. A.; Moskvitina, L. V.; Moskvitin, S. G.; Lebedev, M. P.; Fedorova, G. D.

    2017-12-01

    The work studies the applicability of dunite rocks from Inagli massif (South Yakutia) for the production of mixed (composite) cement. The paper reviews the implementation of dunite for manufacturing materials and products. The chemical and mineral compositions of Inagli massif dunite rocks are presented, which relegate the rocks to magnesia-silicate rocks of low-quality in terms of its application as refractory feedstock due to appreciable serpentinization of dunite. The work presents the results of dunite study in terms of its applicability as an additive to Portland cement. The authors have established that dunite does not feature hydraulicity and can be used as a filling additive to Portland cement in the amount of up to 40%. It was unveiled that the mixed grinding of Portland cement and dunite sand with specific surface area of 5500 cm2/g yields the cement that complies with GOST 31108-2016 for CEM II and CEM V normal-cured cements with strength grades of 32.5 and 42.5. The work demonstrates the benefits of the studies of dunite as a filling additive for producing both Portland cement with mineral component and composite (mixed) cement.

  13. 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.

  14. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2003-06-16

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries. Laboratory testing during the tenth quarter focused on evaluation of the alkali-silica reaction of eight different cement compositions, four of which contain ULHS. The original laboratory procedure for measuring set cement expansion resulted in test specimen erosion that was unacceptable. A different expansion procedure is being evaluated. This report provides a progress summary of ASR testing. The testing program initiated in November produced questionable initial results so the procedure was modified slightly and the testing was reinitiated. The results obtained with the modified procedure showed improvement over data obtained with the original procedure, but questionable data were obtained from several of the compositions. Additional modification of test procedures for compositions containing TXI Lightweight cement are being implemented and testing is ongoing.

  15. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2001-10-23

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses tasks performed in the fourth quarter as well as the other three quarters of the past year. The subjects that were covered in previous reports and that are also discussed in this report include: Analysis of field laboratory data of active cement applications from three oil-well service companies; Preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; Summary of pertinent information from Russian ultra-lightweight cement literature review; and Comparison of compressive strengths of ULHS systems using ultrasonic and crush methods Results reported from the fourth quarter include laboratory testing of ULHS systems along with other lightweight cement systems--foamed and sodium silicate slurries. These comparison studies were completed for two different densities (10.0 and 11.5 lb/gal) and three different field application scenarios. Additional testing included the mechanical properties of ULHS systems and other lightweight systems. Studies were also performed to examine the effect that circulation by centrifugal pump during mixing has on breakage of ULHS.

  16. Relationship between operational variables, fundamental physics and foamed cement properties in lab and field generated foamed cement slurries

    DOE PAGES

    Glosser, D.; Kutchko, B.; Benge, G.; ...

    2016-03-21

    Foamed cement is a critical component for wellbore stability. The mechanical performance of a foamed cement depends on its microstructure, which in turn depends on the preparation method and attendant operational variables. Determination of cement stability for field use is based on laboratory testing protocols governed by API Recommended Practice 10B-4 (API RP 10B-4, 2015). However, laboratory and field operational variables contrast considerably in terms of scale, as well as slurry mixing and foaming processes. Here in this paper, laboratory and field operational processes are characterized within a physics-based framework. It is shown that the “atomization energy” imparted by themore » high pressure injection of nitrogen gas into the field mixed foamed cement slurry is – by a significant margin – the highest energy process, and has a major impact on the void system in the cement slurry. There is no analog for this high energy exchange in current laboratory cement preparation and testing protocols. Quantifying the energy exchanges across the laboratory and field processes provides a basis for understanding relative impacts of these variables on cement structure, and can ultimately lead to the development of practices to improve cement testing and performance.« less

  17. 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

  18. 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.

  19. Effects of tibial rotation on Ober's test and patellar tracking.

    PubMed

    Park, Joo-Hee; Kang, Sun-Young; Choung, Sung-Dae; Jeon, Hye-Seon; Kwon, Oh-Yun

    2016-08-01

    The purpose of this study was to investigate the effects of tibial position on ITB flexibility and patellar position. A total of 31 asymptomatic subjects (21 males, 10 females) were recruited for this investigation. Adduction angle was measured by Ober's test, and PCD was measured by ultrasonography in three different tibial rotation conditions: N, IR, and ER. Repeated measures ANOVA revealed a significant difference in adduction angle and PCD among three different tibial positions (P<0.05). Adduction angle was significantly greater in the N tibial position than in ER (P<0.05). The PCD was significantly greater in N position than in IR (P<0.05). However, the PCD was significantly smaller in IR compared with the N position (P<0.05). These findings support that tibial rotation influences the flexibility of ITB and patellar positions. Therefore, excessive tibial rotation can cause inappropriate patellar positions that eventually lead to knee injury. Therapists should consider tibial rotation when measuring adduction angles because tibial rotation can change Ober's test results and contribute to the consistency of ITB length measurements. Level IV. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Medial tibial stress syndrome: a critical review.

    PubMed

    Moen, Maarten H; Tol, Johannes L; Weir, Adam; Steunebrink, Miriam; De Winter, Theodorus C

    2009-01-01

    Medial tibial stress syndrome (MTSS) is one of the most common leg injuries in athletes and soldiers. The incidence of MTSS is reported as being between 4% and 35% in military personnel and athletes. The name given to this condition refers to pain on the posteromedial tibial border during exercise, with pain on palpation of the tibia over a length of at least 5 cm. Histological studies fail to provide evidence that MTSS is caused by periostitis as a result of traction. It is caused by bony resorption that outpaces bone formation of the tibial cortex. Evidence for this overloaded adaptation of the cortex is found in several studies describing MTSS findings on bone scan, magnetic resonance imaging (MRI), high-resolution computed tomography (CT) scan and dual energy x-ray absorptiometry. The diagnosis is made based on physical examination, although only one study has been conducted on this subject. Additional imaging such as bone, CT and MRI scans has been well studied but is of limited value. The prevalence of abnormal findings in asymptomatic subjects means that results should be interpreted with caution. Excessive pronation of the foot while standing and female sex were found to be intrinsic risk factors in multiple prospective studies. Other intrinsic risk factors found in single prospective studies are higher body mass index, greater internal and external ranges of hip motion, and calf girth. Previous history of MTSS was shown to be an extrinsic risk factor. The treatment of MTSS has been examined in three randomized controlled studies. In these studies rest is equal to any intervention. The use of neoprene or semi-rigid orthotics may help prevent MTSS, as evidenced by two large prospective studies.

  1. Foot and ankle function after tibial overlengthening.

    PubMed

    Emara, Khaled M; Diab, Ramy Ahmed; El Ghazali, Sherif; Farouk, Amr; El Kersh, Mohamed Ahmed

    2014-01-01

    Lengthening the tibia more than 25% of its original length can be indicated for proximal femoral deficiency, poliomyelitis, or femoral infected nonunion. Such lengthening of the tibia can adversely affect the ankle or foot shape and function. The present study aimed to assess the effect of tibial lengthening of more than 25% of its original length on the foot and ankle shape and function compared with the preoperative condition. This was a retrospective study of 13 children with severe proximal focal femoral deficiency, Aitken classification type D, who had undergone limb lengthening from June 2000 to June 2008 using Ilizarov external fixators. The techniques used in tibial lengthening included lengthening without intramedullary rodding and lengthening over a nail. The foot assessment was done preoperatively, at fixator removal, and then annually for 3 years, documenting the range of motion and deformity of the ankle and subtalar joints and big toe and the navicular height, calcaneal pitch angle, and talo-first metatarsal angle. At fixator removal, all cases showed equinocavovarus deformity, with decreased ankle, subtalar, and big toe motion. The mean American Orthopedic Foot and Ankle Society score was significantly reduced. During follow-up, the range of motion, foot deformity, and American Orthopedic Foot and Ankle Society score improved, reaching nearly to the preoperative condition by 2 years of follow-up. The results of our study have shown that tibial overlengthening has an adverse effect on foot and ankle function. This effect was reversible in the patients included in the present study. Lengthening of more than 25% can be safely done after careful discussion with the patients and their families about the probable effects of lengthening on foot and ankle function. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  2. In vivo performance of a reduced-modulus bone cement

    NASA Astrophysics Data System (ADS)

    Forehand, Brett Ramsey

    Total joint replacement has become one of the most common procedures in the area of orthopedics and is often the solution in patients with diseased or injured hip joints. Component loosening is a significant problem and is primarily caused by bone resorption at the bone-cement interface in cemented implants. It is our hypothesis that localized shear stresses are responsible for the resorption. It was previously shown analytically that local stresses at the interface could be reduced by using a cement of lower modulus. A new reduced modulus cement, polybutyl methylmethacrylate (PBMMA), was developed to test the hypothesis. PBMMA was formulated to exist as polybutyl methacrylate filler in a polymethyl methacrylate matrix. The success of PBMMA cement is based largely on the fact that the polybutyl component of the cement will be in the rubbery state at body temperature. In vitro characterization of the cement was undertaken previously and demonstrated a modulus of approximately one-eighth that of conventional bone cement, polymethyl methacrylate (PMMA) and increased fracture toughness. The purpose of this experiment was to perform an in vivo comparison of the two cements. A sheep model was selected. Total hip arthroplasty was performed on 50 ewes using either PBMMA or PMMA. Radiographs were taken at 6 month intervals. At one year, the contralateral femur of each sheep was implanted so that each animal served as its own control, and the animals were sacrificed. The stiffness of the bone-cement interface of the femoral component within the femur was assessed by applying a torque to the femoral component and demonstrated a significant difference in loosening between the cements when the specimens were tested in external rotation (p < 0.007). Evaluation of the mechanical data also suggests that the PBMMA sheep had a greater amount of loosening for each subject, 59% versus 4% for standard PMMA. A radiographic analysis demonstrated more signs of loosening in the PMMA series

  3. The potential of fly ash for cement manufacture

    SciTech Connect

    Majling, J. . Dept. of Ceramics); Roy, D.M. )

    1993-10-01

    The fly ash from fluidized bed combustion is normally not suitable as a raw material for cement manufacture, because of high sulfur content. Calcium sulfoaluminate belite cement clinkers may provide a way to make this fly ash usable as a cement raw material. A well-known computational technique can be used to identify mixture/phase composition relationships for the raw materials. This article therefore analyzes binary mixtures composed of high-sulfate, fluidized bed combustion ashes. Emphasis is given to creating suitable raw mixtures from by-products of the same fluidized bed reactor unit. If feasible, the mixture components would then be mutually corrective and there would be no need to transport either component for long distances when used in the manufacture of proposed cements. The examples chosen also illustrate the use of the computation method, which may be applied broadly.

  4. Dentin-cement Interfacial Interaction

    PubMed Central

    Atmeh, A.R.; Chong, E.Z.; Richard, G.; Festy, F.; Watson, T.F.

    2012-01-01

    The interfacial properties of a new calcium-silicate-based coronal restorative material (Biodentine™) and a glass-ionomer cement (GIC) with dentin have been studied by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), micro-Raman spectroscopy, and two-photon auto-fluorescence and second-harmonic-generation (SHG) imaging. Results indicate the formation of tag-like structures alongside an interfacial layer called the “mineral infiltration zone”, where the alkaline caustic effect of the calcium silicate cement’s hydration products degrades the collagenous component of the interfacial dentin. This degradation leads to the formation of a porous structure which facilitates the permeation of high concentrations of Ca2+, OH-, and CO32- ions, leading to increased mineralization in this region. Comparison of the dentin-restorative interfaces shows that there is a dentin-mineral infiltration with the Biodentine, whereas polyacrylic and tartaric acids and their salts characterize the penetration of the GIC. A new type of interfacial interaction, “the mineral infiltration zone”, is suggested for these calcium-silicate-based cements. PMID:22436906

  5. High temperature lightweight foamed cements

    DOEpatents

    Sugama, Toshifumi.

    1989-10-03

    Cement slurries are disclosed which are suitable for use in geothermal wells since they can withstand high temperatures and high pressures. The formulation consists of cement, silica flour, water, a retarder, a foaming agent, a foam stabilizer, and a reinforcing agent. A process for producing these cements is also disclosed. 3 figs.

  6. Reducing cement's CO2 footprint

    USGS Publications Warehouse

    van Oss, Hendrik G.

    2011-01-01

    The manufacturing process for Portland cement causes high levels of greenhouse gas emissions. However, environmental impacts can be reduced by using more energy-efficient kilns and replacing fossil energy with alternative fuels. Although carbon capture and new cements with less CO2 emission are still in the experimental phase, all these innovations can help develop a cleaner cement industry.

  7. Cement Mason's Curriculum. Instructional Units.

    ERIC Educational Resources Information Center

    Hendirx, Laborn J.; Patton, Bob

    To assist cement mason instructors in providing comprehensive instruction to their students, this curriculum guide treats both the skills and information necessary for cement masons in commercial and industrial construction. Ten sections are included, as follow: related information, covering orientation, safety, the history of cement, and applying…

  8. High temperature lightweight foamed cements

    DOEpatents

    Sugama, Toshifumi

    1989-01-01

    Cement slurries are disclosed which are suitable for use in geothermal wells since they can withstand high temperatures and high pressures. The formulation consists of cement, silica flour, water, a retarder, a foaming agent, a foam stabilizer, and a reinforcing agent. A process for producing these cements is also disclosed.

  9. Cementing a wellbore using cementing material encapsulated in a shell

    DOEpatents

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Spadaccini, Christopher M.; Cowan, Kenneth Michael

    2016-08-16

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  10. Cementing a wellbore using cementing material encapsulated in a shell

    DOEpatents

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Floyd, III, William C.; Spadaccini, Christopher M.; Vericella, John J.; Cowan, Kenneth Michael

    2017-03-14

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  11. Research of cost aspects of cement pavements construction

    NASA Astrophysics Data System (ADS)

    Bezuglyi, Artem; Illiash, Sergii; Tymoshchuk, Oleksandr

    2017-09-01

    The tendency to increasing traffic volume on public roads and to increased axle loads of vehicles makes the road scientists to develop scientifically justified methods for preserving the existing and developing the new transport network of Ukraine. One of the options for solving such issues is the construction of roads with rigid (cement concrete) pavement. However, any solution must be justified considering technical and economic components. This paper presents the results of the research of cost aspects of cement pavements construction.

  12. Retention, marginal leakage, and cement solubility of provisional crowns cemented with temporary cement containing stannous fluoride.

    PubMed

    Lewinstein, Israel; Fuhrer, Nitzan; Gelfand, Katerina; Cardash, Harold; Pilo, Raphael

    2003-01-01

    This in vitro study investigated the (1) retention and microleakage of provisional crowns cemented with temporary cements to which stannous fluoride (SnF2) was added, and (2) solubility of these cements. Provisional crowns were constructed of acrylic resin with shoulder preparations for 12 molars. The crowns were luted with Tempbond, Tempbond NE, and Freegenol temporary cements, and also with SnF2 added to these cements. Specimens were thermocycled 100 times, stored for 6 days, and immersed in 0.5% basic fuschin. Seven days after cementation, crown removal (retention) tests were conducted. Marginal leakage was assessed using a five-level scale to score dye penetration. Solubility in water of the cements with and without SnF2 was assessed using cement disks. Freegenol was more retentive than the other cements. The incorporation of SnF2 significantly increased the retention capacity of Freegenol and Tempbond NE but had no effect on Tempbond. Tempbond showed significantly higher dye penetration than Freegenol. The addition of SnF2 did not alter the dye penetration of the cements. There were no significant differences in the solubility of the cements. However, the incorporation of SnF2 increased the solubility of Freegenol and Tempbond NE (P < .001) and Tempbond (P < .01). The addition of SnF2 increased the retention of temporary crowns cemented with Tempbond NE and Freegenol but did not affect the retention of those cemented with Tempbond. The marginal leakage of crowns cemented with the tested temporary cements with and without the incorporation of SnF2 was similar. However, the addition of SnF2 increased the solubility of the cements.

  13. 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

  14. Anteromedial tibial tubercle transfer without bone graft.

    PubMed

    Fulkerson, J P; Becker, G J; Meaney, J A; Miranda, M; Folcik, M A

    1990-01-01

    We followed 30 patients for more than 2 years after anteromedial tibial tubercle transfer for persistent patellofemoral pain associated with patellar articular degeneration. Twelve of these patients were followed more than 5 years. We report 93% good and excellent results subjectively and 89% good and excellent results objectively. The quality of improvement was sustained in all 12 of the patients who were evaluated again after more than 5 years from surgery. When examined separately, 75% of those patients with advanced patellar arthrosis achieved a good result; none of these patients achieved an excellent result. Postoperative continuous passive motion has markedly reduced the incidence of stiffness. Serious complications such as compartment syndrome, infection, and skin slough were avoided completely in 51 consecutive cases. Patellofemoral contact pressure studies in five cadaver knees have shown that anteromedial tibial tubercle transfer can provide substantial reduction of patellofemoral contact stress while helping to balance medial and lateral facet pressures. This surgical procedure is mechanically and clinically successful for alleviating intractable pain related to patellar malalignment and articular degeneration. This procedure enables the majority of appropriately selected patients with malalignment and patellar articular degeneration to resume increased levels of activity with substantially diminished pain.

  15. 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.

  16. Identifying improvement potentials in cement production with life cycle assessment.

    PubMed

    Boesch, Michael Elias; Hellweg, Stefanie

    2010-12-01

    Cement production is an environmentally relevant process responsible for 5% of total anthropogenic carbon dioxide emissions and 7% of industrial fuel use. In this study, life cycle assessment is used to evaluate improvement potentials in the cement production process in Europe and the USA. With a current fuel substitution rate of 18% in Europe and 11% in the USA, both regions have a substantial potential to reduce greenhouse gas emissions and save virgin resources by further increasing the coprocessing of waste fuels. Upgrading production technology would be particularly effective in the USA where many kiln systems with very low energy efficiency are still in operation. Using best available technology and a thermal substitution rate of 50% for fuels, greenhouse gas emissions could be reduced by 9% for Europe and 18% for the USA per tonne of cement. Since clinker production is the dominant pollution producing step in cement production, the substitution of clinker with mineral components such as ground granulated blast furnace slag or fly ash is an efficient measure to reduce the environmental impact. Blended cements exhibit substantially lower environmental footprints than Portland cement, even if the substitutes feature lower grindability and require additional drying and large transport distances. The highest savings in CO(2) emissions and resource consumption are achieved with a combination of measures in clinker production and cement blending.

  17. Quantification of third body damage to the tibial counterface in mobile bearing knees.

    PubMed

    Jones, V C; Williams, I R; Auger, D D; Walsh, W; Barton, D C; Stone, M H; Fisher, J

    2001-01-01

    Fourteen pairs of explanted low contact stress (LCS) tibial interface components: six rotating platform (RP), six meniscal (MN) and two anterior-posterior (AP) glide designs, have been analysed with particular attention paid to the condition of the tibial counterfaces. The average surface roughness, Ra, for the tibial trays ranged from 0.01 to 0.087 micron, significantly greater than the unworn control measurement of 0.008 micron. The scratch geometry analysis showed that the scratch peaks were found to be consistently of a lower aspect ratio than the scratch valleys and under 1 micron in height (average asperity height Rp = 0.52 micron, aspect ratio delta p = 0.01, average asperity depth Rv = 1.10 microns, delta v = 0.05). The largest scratches were 3-4 microns in both Rp and Rv. In vitro tests have shown that ultra-high molecular weight polyethylene (UHMWPE) wear increases in the presence of counterface scratches perpendicular to the direction of motion. In these explants, the unidirectional motion produced scratches parallel to the direction of sliding which is predicted to produce a smaller increase in UHMWPE wear. Other designs in mobile bearing knees have less constrained motion at the tibial counterface and this has been shown to accelerate wear; it may also lead to a further increase in wear in the presence of third body scratches. It may be possible in future knee designs to reduce this type of wear damage by introducing alternative materials or coatings which are more resistant to scratching and surface roughening.

  18. Effect of tibial tubercle elevation on biomechanics of the entire knee joint under muscle loads.

    PubMed

    Shirazi-Adl, A; Mesfar, W

    2007-03-01

    Anterior elevation of the tibial tubercle, known as Maquet procedure, is performed to reduce excessive patellofemoral contact stresses in knee joints with patellofemoral osteoarthritis and anterior pain. Previous investigations, however, have entirely focused on the likely effect of tibial tubercle elevation procedure on biomechanics of contact at the patellofemoral joint with no attention what-so-ever to associated alterations in biomechanics of the tibiofemoral joint. Using a validated 3D nonlinear finite element model of the entire knee joint, the effect of 1.25 cm and 2.5 cm tubercle elevations on the entire knee joint biomechanics was investigated under constant quadriceps load of 411 N alone or combined with hamstrings co-activation of 205.5 N under joint angles of 0-90 degrees. Results confirm the effectiveness of this procedure in reducing patellofemoral contact forces, especially at smaller flexion angles. Maximum contact stress substantially decreased at full extension but increased at 90 degrees. Substantial effects of tuberosity elevation on tibial kinematics, cruciate ligament forces, tibiofemoral contact forces and extensor lever arm were found. The posterior cruciate ligament and tibiofemoral contact forces at larger flexion angles considerably increased whereas the anterior cruciate ligament and tibiofemoral contact forces at near full extension angles decreased. Overall, the extent of changes depended on the magnitude of anterior elevation, joint flexion angle and loading considered. Biomechanics of the tibiofemoral joint were significantly influenced by tibial tubercle elevation. Current results advocate the need for an integral view of the entire knee joint in management of various joint disorders rather than a view in which each component is considered and treated in isolation with no due attention to perturbations caused and associated consequences.

  19. Economics of All-Polyethylene Versus Metal-Backed Tibial Prosthesis Designs.

    PubMed

    Chambers, Monique C; El-Othmani, Mouhanad M; Sayeed, Zain; Anoushiravani, Afshin; Schnur, Anne-Kathrin; Mihalko, William M; Saleh, Khaled J

    2016-05-01

    With the large number of total knee arthroplasties being performed and expectations that these numbers will be on the rise over the coming decades, efforts to provide cost-efficient care are of greater interest. The preferred design of knee arthroplasty implants has changed over time, with the original all-polyethylene tibial (APT) design being replaced by metal-backed tibial (MBT) components, as well as more recent considerations of newer APT designs. Modern APT components have been shown to have similar or superior outcomes than MBT components. Despite their limitations, APT components can be used to reduce the economic burden to the provider, medical institution, and health care system as a whole. There is a paucity of evidence-based literature directly comparing the cost associated with APT and MBT components. The purpose of this report is to review the literature to assess the available data regarding direct and indirect costs of both designs so that orthopedic surgeons can account for economic differences in everyday practice. [Orthopedics. 2016; 39(3):S61-S66.]. Copyright 2016, SLACK Incorporated.

  20. MRI of Polyethylene Tibial Inserts in Total Knee Arthroplasty: Normal and Abnormal Appearances.

    PubMed

    Li, Angela E; Sneag, Darryl B; Miller, Theodore T; Lipman, Joseph D; Padgett, Douglas E; Potter, Hollis G

    2016-06-01

    The purpose of this study was to describe the normal and abnormal MRI appearances of polyethylene tibial inserts. Subjects who underwent MRI before revision total knee arthroplasty were identified. The polyethylene tibial insert's shape was categorized on MRI, and the presence of abnormalities was noted. The shape of the polyethylene tibial insert varied with the design. Polyethylene tibial insert abnormalities seen on MRI included displacement and fracture. MRI distinguishes various designs of polyethylene tibial inserts and can show associated abnormalities.

  1. Carbon Capture in the Cement Industry: Technologies, Progress, and Retrofitting.

    PubMed

    Hills, Thomas; Leeson, Duncan; Florin, Nicholas; Fennell, Paul

    2016-01-05

    Several different carbon-capture technologies have been proposed for use in the cement industry. This paper reviews their attributes, the progress that has been made toward their commercialization, and the major challenges facing their retrofitting to existing cement plants. A technology readiness level (TRL) scale for carbon capture in the cement industry is developed. For application at cement plants, partial oxy-fuel combustion, amine scrubbing, and calcium looping are the most developed (TRL 6 being the pilot system demonstrated in relevant environment), followed by direct capture (TRL 4-5 being the component and system validation at lab-scale in a relevant environment) and full oxy-fuel combustion (TRL 4 being the component and system validation at lab-scale in a lab environment). Our review suggests that advancing to TRL 7 (demonstration in plant environment) seems to be a challenge for the industry, representing a major step up from TRL 6. The important attributes that a cement plant must have to be "carbon-capture ready" for each capture technology selection is evaluated. Common requirements are space around the preheater and precalciner section, access to CO2 transport infrastructure, and a retrofittable preheater tower. Evidence from the electricity generation sector suggests that carbon capture readiness is not always cost-effective. The similar durations of cement-plant renovation and capture-plant construction suggests that synchronizing these two actions may save considerable time and money.

  2. Mineral resource of the month: hydraulic cement

    USGS Publications Warehouse

    van Oss, Hendrik G.

    2012-01-01

    Hydraulic cements are the binders in concrete and most mortars and stuccos. Concrete, particularly the reinforced variety, is the most versatile of all construction materials, and most of the hydraulic cement produced worldwide is portland cement or similar cements that have portland cement as a basis, such as blended cements and masonry cements. Cement typically makes up less than 15 percent of the concrete mix; most of the rest is aggregates. Not counting the weight of reinforcing media, 1 ton of cement will typically yield about 8 tons of concrete.

  3. Medial tibial stress syndrome: conservative treatment options.

    PubMed

    Galbraith, R Michael; Lavallee, Mark E

    2009-10-07

    Medial tibial stress syndrome (MTSS), commonly known as "shin splints," is a frequent injury of the lower extremity and one of the most common causes of exertional leg pain in athletes (Willems T, Med Sci Sports Exerc 39(2):330-339, 2007; Korkola M, Amendola A, Phys Sportsmed 29(6):35-50, 2001; Hreljac A, Med Sci Sports Exerc 36(5):845-849, 2004). Although often not serious, it can be quite disabling and progress to more serious complications if not treated properly. Often, the cause of MTSS is multi-factorial and involves training errors and various biomechanical abnormalities. Few advances have been made in the treatment of MTSS over the last few decades. Current treatment options are mostly based on expert opinion and clinical experience. The purpose of this article is to review published literature regarding conservative treatment options for MTSS and provide recommendations for sports medicine clinicians for improved treatment and patient outcomes.

  4. Posterior tibial nerve lesions in ankle arthroscopy.

    PubMed

    Cugat, Ramon; Ares, Oscar; Cuscó, Xavier; Garcia, Montserrat; Samitier, Gonzalo; Seijas, Roberto

    2008-05-01

    Ankle arthroscopy provides a minimally invasive approach to the diagnosis and treatment of certain ankle disorders. Neurological complications resulting from ankle arthroscopy have been well documented in orthopaedic and podiatric literature. Owing to the superficial location of the ankle joint and the abundance of overlying periarticular neurovascular structures, complications reported in ankle arthroscopy are greater than those reported for other joints. In particular, all reported neurovascular injuries following ankle arthroscopy have been the direct result of distractor pin or portal placement. The standard posteromedial portal has recognized risks because of the proximity of the posterior neurovascular structures. There can be considerable variability in the course of these portals and their proximity to the neurovascular structures. We found one report of intra-articular damage to the posterior tibial nerve as a result of ankle arthroscopy in the English-language literature and we report this paper as a second case described in the literature.

  5. Rheological Influence of Synthetic Zeolite on Cement Pastes

    NASA Astrophysics Data System (ADS)

    Baldino, N.; Gabriele, D.; Frontera, P.; Crea, F.; de Cindio, B.

    2008-07-01

    Self Compacting Concrete (SCC) is characterized by specific and particular mechanical properties, often due to the addition of components, able to modify the paste rheology. Concrete properties are strongly affected by characteristics of the fresh cement paste that is the continuous phase dispersing larger aggregates. Therefore, aiming to characterize mechanical properties of final concrete is relevant to know rheological properties of the base cement paste. In this work cement pastes for SCC were prepared by using, as additive, synthetic zeolite 5A in different amounts and they were analyzed by small amplitude oscillations. Experimental results have shown a relationship between dynamic moduli and zeolite content, identifying a proper level of zeolite addition. Moreover samples containing traditional fine additives, such as silica fume and limestone, were prepared and experimental data were compared to those obtained by using zeolite. It was found that zeolite seems to give better properties to cement paste than other additives can do.

  6. Changes in posterior tibial slope angle in patients undergoing open-wedge high tibial osteotomy for varus gonarthrosis.

    PubMed

    Ozel, Omer; Yucel, Bulent; Mutlu, Serhat; Orman, Osman; Mutlu, Harun

    2017-01-01

    In this study, postoperative changes in the posterior tibial slope angle and clinical outcomes following open-wedge high tibial osteotomy were evaluated. This study included 39 knees (18 left, 21 right) of 35 patients (three male, 32 female; median age, 53 years; age range 37-64 years) with symptomatic isolated medial joint osteoarthritis who underwent open-wedge high tibial osteotomy and fixation with a Puddu plate. The patients were clinically assessed according to the Lysholm knee score, a visual analogue pain scale, and a patient satisfaction questionnaire. Radiological assessment was made according to the changes in the posterior tibial slope angle and the correlation between these changes and clinical signs. The median follow-up period was 11 years (range 7-14 years). Significant improvements were observed in the preoperative and postoperative clinical scores of the Lysholm knee scale, visual analogue pain scale, and patient satisfaction questionnaire (p < 0.05). Radiological assessment showed that the posterior tibial slope angle was significantly higher during the postoperative and follow-up periods (p  0.05). There was no correlation between the postoperative Lysholm scores and the increase in the posterior tibial slope angle (p = n.s.). We conclude that both the conventional Puddu plate design and its anteromedial plate placement are what increase the tibial slope after an opening-wedge proximal tibial osteotomy. Therefore, current new plate design may help preserve the posterior tibial slope angle. IV.

  7. Current developments concerning medial tibial stress syndrome.

    PubMed

    Craig, Debbie I

    2009-12-01

    Medial tibial stress syndrome (MTSS) is one of the most common lower leg injuries in athletes who run. Studies have reported MTSS to occur in 4% to 20% of this population. It can be defined as an overuse injury that creates pain over an area covering the distal to middle third of the posteriomedial tibial border, which occurs during exercise and creates cyclic loading. Differential diagnosis includes ischemic disorders and stress fractures. Although the pathology of this injury is understood, the etiology is less agreed upon. This makes it difficult for clinicians to diagnose and treat this common injury. The purpose of this article is to present health care practitioners with the most current information regarding MTSS so they can better diagnose and treat this common injury. To this end, a literature review was conducted, with the most current results presented. The areas of etiological theories, imaging techniques, and treatment options for MTSS were searched. Five of the most prevalent etiological theories are presented with supporting evidence. Of the imaging tools available to the clinician, magnetic resonance imaging (MRI) and bone scintigraphy have comparable specificity and sensitivity. Clinicians should first make the clinical diagnosis of MTSS, however, because of high percentages of positive MRI scans in asymptomatic patients. There have been few randomized controlled trials investigating treatment options for athletes with MTSS. Those that have been performed rendered no significant findings, leading researchers to conclude that rest is equal to or better than other treatment options. Given the evidence, treatment suggestions for practitioners caring for athletes with MTSS are provided.

  8. 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

  9. Change in Posterior Tibial Slope After Open-Wedge and Closed-Wedge High Tibial Osteotomy: A Meta-analysis.

    PubMed

    Nha, Kyung-Wook; Kim, Hyun-Jung; Ahn, Hyeong-Sik; Lee, Dae-Hee

    2016-11-01

    It is unclear whether open- or closed-wedge high tibial osteotomy (HTO) results in significant changes in posterior tibial slope, with no consensus on the magnitude of such changes. Furthermore, methods of measuring posterior tibial slope differ among studies. This meta-analysis was therefore designed to evaluate whether posterior tibial slope increases after open-wedge HTO and decreases after closed-wedge HTO and to quantify the magnitudes of the slope changes after open- and closed-wedge HTO using various methods of measuring posterior tibial slope. Posterior tibial slope increases after open-wedge and decreases after closed-wedge HTO. The magnitude of change is similar for the 2 methods, and the value obtained for posterior tibial slope change is affected by the method of measurement. Meta-analysis. Multiple comprehensive databases, including MEDLINE, EMBASE, the Cochrane Library, and KoreaMed, were searched for studies that evaluated the posterior slope of the proximal tibia in patients who had undergone open- and/or closed-wedge HTO. Studies were included that compared pre- and postoperative posterior tibial slopes, regardless of measurement method, including anterior and posterior tibial cortex or tibial shaft axis as a reference line, in patients who underwent open- or closed-wedge HTO. The quality of each included study was appraised with the Newcastle-Ottawa Scale. Twenty-seven studies were included in the meta-analysis. Pooled data, which included subgroups of 3 methods, showed that posterior tibial slope increased 2.02° (95% CI, 2.66° to 1.38°; P = .005) after open-wedge HTO and decreased 2.35° (95% CI, 1.38° to 3.32°; P < .001) after closed-wedge HTO. This meta-analysis confirmed that posterior tibial slope increased after open-wedge HTO and decreased after closed-wedge HTO when the results of a variety of measurement methods were pooled. The magnitude of change after open- and closed-wedge HTO was similar and small (approximately 2°), suggesting

  10. US cement industry

    SciTech Connect

    Nisbet, M.A.

    1997-12-31

    This paper describes the cement and concrete industry, and provides data on energy use and carbon dioxide emissions. The potential impact of an energy tax on the industry is briefly assessed. Opportunities identified for reducing carbon dioxide emissions include improved energy efficiency, alternative fuels, and alternative materials. The key factor in determining CO{sub 2} emissions is the level of domestic production. The projected improvement in energy efficiency and the relatively slow growth in domestic shipments indicate that CO{sub 2} emissions in 2000 should be about 5% above the 1990 target. However, due to the cyclical nature of cement demand, emissionsmore » will probably be above target levels during peak demand and below target levels during demand troughs. 7 figs., 2 tabs.« less

  11. US cement industry

    SciTech Connect

    Nisbet, M.A.

    1997-12-31

    This paper describes the cement and concrete industry, and provides data on energy use and carbon dioxide emissions. The potential impact of an energy tax on the industry is briefly assessed. Opportunities identified for reducing carbon dioxide emissions include improved energy efficiency, alternative fuels, and alternative materials. The key factor in determining CO{sub 2} emissions is the level of domestic production. The projected improvement in energy efficiency and the relatively slow growth in domestic shipments indicate that CO{sub 2} emissions in 2000 should be about 5% above the 1990 target. However, due to the cyclical nature of cement demand, emissions will probably be above target levels during peak demand and below target levels during demand troughs. 7 figs., 2 tabs.

  12. Well cementing in permafrost

    SciTech Connect

    Wilson, W.N.

    1979-12-04

    A process for cementing a string of pipe in the permafrost region of a borehole of a well wherein aqueous drilling fluid actually used in drilling the wellbore in the permafrost region of a wellbore is employed. The drilling fluid contains or is adjusted to contain from about 2 to about 16 volume percent solids. Mixing with the drilling fluid (1) an additive selected from the group consisting of lignosulfonate, lignite, tannin, and mixtures thereof, (2) sufficient base to raise the pH of the drilling fluid into the range of from about 9 to about 12, and (3) cementitious materialmore » which will harden in from about 30 to about 40 hours at 40/sup 0/F. The resulting mixture is pumped into the permafrost region of a wellbore to be cemented and allowed to harden in the wellbore. There is also provided a process for treating an aqueous drilling fluid after it has been used in drilling the wellbore in permafrost, and a cementitious composition fro cementing in a permafrost region of a wellbore.« less

  13. Well cementing in permafrost

    SciTech Connect

    Wilson, W.N.

    1980-01-01

    A process for cementing a string of pipe in the permafrost region of a borehole of a well wherein aqueous drilling fluid actually used in drilling the wellbore in the permafrost region of a wellbore is employed. The drilling fluid contains or is adjusted to contain from about 2 to about 16 volume percent solids. Mixing with the drilling fluid (1) an additive selected from the group consisting of ligno-sulfonate, lignite, tannin, and mixtures thereof, (2) sufficient base to raise the pH of the drilling fluid into the range of from about 9 to about 12, and (3) cementitious materialmore » which will harden in from about 30 to about 40 hours at 40/sup 0/F. The resulting mixture is pumped into the permafrost region of a wellbore to be cemented and allowed to harden in the wellbore. There is also provided a process for treating an aqueous drilling fluid after it has been used in drilling the wellbore in permafrost, and a cementitious composition for cementing in a permafrost region of a wellbore.« less

  14. 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.

  15. Tibial Bowing and Pseudarthrosis in Neurofibromatosis Type 1

    DTIC Science & Technology

    2015-01-01

    parent of tibial bowing that was thought to be bilateral with possible increase on the right . Bracing was used bilaterally for 6 months and then...Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Anterolateral tibial bowing is a morbid skeletal manifestation observed in 5% of children with...skeletal manifestation observed in 5% of children with neurofibromatosis type 1 (NF1), typically identified in infancy (Friedman and Birch, 1997). The

  16. 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

  17. 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.

  18. The effect of wedge and tibial slope angles on knee contact pressure and kinematics following medial opening-wedge high tibial osteotomy.

    PubMed

    Black, Marianne S; d'Entremont, Agnes G; McCormack, Robert G; Hansen, Gregory; Carr, Derek; Wilson, David R

    2018-01-01

    High tibial osteotomy is a surgical procedure to treat medial compartment osteoarthritis in varus knees. The reported success rates of the procedure are inconsistent, which may be due to sagittal plane alignment of the osteotomy. The objective of this study was to determine the effect of changing tibial slope, for a range of tibial wedge angles in high tibial osteotomy, on knee joint contact pressure location and kinematics during continuous loaded flexion/extension. Seven cadaveric knee specimens were cycled through flexion and extension in an Oxford knee-loading rig. The osteotomy on each specimen was adjusted to seven clinically relevant wedge and slope combinations. We used pressure sensors to determine the position of the centre of pressure in each compartment of the tibial plateau and infrared motion capture markers to determine tibiofemoral and patellofemoral kinematics. In early knee flexion, a 5° increase in tibial slope shifted the centre of pressure in the medial compartment anteriorly by 4.5mm (P≤0.001), (from the neutral slope/wedge position). Increasing the tibial slope also resulted in the tibia translating anteriorly (P≤0.001). Changes to the tibial slope during high tibial osteotomy for all tested wedge angles shifted the centre of pressure in both the medial and lateral compartments substantially and altered knee kinematics. Tibial slope should be controlled during high tibial osteotomy to prevent unwanted changes in tibial plateau contact loads. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Glass ionomer restorative cement systems: an update.

    PubMed

    Berg, Joel H; Croll, Theodore P

    2015-01-01

    Glass ionomer cements have been used in pediatric restorative dentistry for more than two decades. Their usefulness in clinical dentistry is preferential to other materials because of fluoride release from the glass component, biocompatibility, chemical adhesion to dentin and enamel, coefficient of thermal expansion similar to that of tooth structure, and versatility. The purpose of this paper was to review the uses of glass ionomer materials in pediatric dentistry, specifically as pit and fissure sealants, dentin and enamel replacement repair materials, and luting cements, and for use in glass ionomer/resin-based composite stratification tooth restoration (the sandwich technique). This article can also be used as a guide to research and clinical references regarding specific aspects of the glass ionomer systems and how they are used for young patients.

  20. [Haemotoxicity of dental luting cements].

    PubMed

    Anders, A; Welker, D

    1989-06-01

    A glass ionomer luting cement (AquaCem) shows a relatively low haemolytic activity in comparison with two zinc phosphate cements. Especially the initial irritation by this cement is smaller. Although it is possible that AquaCem particularly, in unfavourable cases, may damage the pulpa dentin system; this is due to the slowly decrease of the haemolytic activity with increasing of the probes. We found that Adhesor showed in dependence of the batches a varying quality.

  1. Center for Cement Composite Materials

    DTIC Science & Technology

    1990-01-31

    because of the intrinsic microporosity of the binder a compressive strength limit of about 30,000 psi is reached. U U * 2 DSP cements act as insulating...microaggregate. The porosity of the paste is predominantly the intrinsic microporosity of the C-S-H binder. However, this is difficult to measure accurately...studied a magnesium triphosphate cement, as a precursor to polyphosphate cements and is exploring inorganic- polymer composites at the molecular levels

  2. Crosslink Density Is Reduced and Oxidation Is Increased in Retrieved Highly Crosslinked Polyethylene TKA Tibial Inserts.

    PubMed

    Liu, Tong; Esposito, Christina I; Burket, Jayme C; Wright, Timothy M

    2017-01-01

    The wear resistance of highly crosslinked polyethylene depends on crosslink density, which may decrease with in vivo loading, leading to more wear and increased oxidation. The relationship among large and complex in vivo mechanical stresses, breakdown of the polyethylene crosslinks, and oxidative degradation is not fully understood in total knee arthroplasty (TKA). We wished to determine whether crosslink density is reduced at the articular surfaces of retrieved tibial inserts in contact areas exposed to in vivo mechanical stress. (1) Does polyethylene crosslink density decrease preferentially in regions of the articular surface of thermally stabilized crosslinked polyethylene tibial components exposed to mechanical stress in vivo; and (2) what is the ramification of decreased crosslink density in TKA in terms of accompanying oxidation of the polyethylene? From May 2011 to January 2014, 90 crosslinked polyethylene tibial components were retrieved during revision surgery as a part of a long-standing implant retrieval program. Forty highly crosslinked polyethylene tibial inserts (27 posterior-stabilized designs and 13 cruciate-retaining designs) retrieved for instability (15 cases), stiffness (11), infection (six), aseptic loosening (four), pain (two), and malposition (two) after a mean time of 18 months were inspected microscopically to identify loaded (burnished) and unloaded (unburnished) regions on the articular surfaces. Swell ratio testing was done according to ASTM F2214 to calculate crosslink density and infrared spectroscopy was used according to ASTM F2102 to measure oxidation. The region of the tibial insert influenced crosslink density. Loaded surface regions had a mean crosslink density of 0.19 (95% confidence interval [CI], 0.18-0.19) mol/dm 3 , lower than the other three regions (loaded subsurface, unloaded surface, and unloaded subsurface), which had crosslink densities of 0.21 (95% CI, 0.21-0.22; p < 0.01) mol/dm 3 . Peak oxidation levels were higher

  3. Same-Level Fracture of the Tibial Metal Tray and Polyethylene Insert After Total Knee Arthroplasty.

    PubMed

    Kang, Jong Yeal; Lee, Yong Seuk

    2016-07-01

    The authors report a case of failure fracture of the tibial metal tray and polyethylene insert at the same level in a 73-year-old woman 10 years after total knee arthroplasty using the AMK Total Knee System (DePuy, Warsaw, Indiana). Causes of this fracture are analyzed and discussed, with the focus on the importance of component design, position, and size. The overall aim of this case report is for orthopedic surgeons to avoid this complication in total knee arthroplasty by paying attention to these controllable factors. [Orthopedics. 2016; 39(4):e787-e789.]. Copyright 2016, SLACK Incorporated.

  4. Minimum 5-year Follow-up Results of Minimally Invasive Total Knee Arthroplasty Using Mini-Keel Modular Tibial Implant.

    PubMed

    Yoo, Ju-Hyung; Park, Byoung-Kyu; Han, Chang-Dong; Oh, Hyun-Cheol; Park, Sang-Hoon

    2014-09-01

    To evaluate the minimum 5-year mid-term clinical and radiological results of minimally invasive surgery total knee arthroplasty (MIS-TKA) using a mini-keel modular tibia component. We retrospectively evaluated 254 patients (361 cases) who underwent MIS-TKA between 2005 and 2006. The latest clinical and radiological assessments were done in 168 cases that had been followed on an outpatient basis for more than 5 postoperative years. Clinical results were assessed using the Hospital for Special Surgery (HSS) score and Knee Society score. Radiological evaluation included measurements of knee alignment. The average postoperative knee range of motion and HSS score were 134.3°±12.4° and 92.7°±7.0°, respectively. The average postoperative femorotibial angle and tibial component alignment angle were 5.2°±1.7° valgus and 90.2°±1.6°, respectively. The average tibial component posterior inclination was 4.8°±2.1°. The percentage of cases with tibial component alignment angle of 90°±3° was 96.1%, and that with the femorotibial angle of 6°±3° valgus was 94.0%. Radiolucent lines were observed in 20 cases (12.0%): around the femur, tibia, and patella in 14 cases, 10 cases, and 1 case, respectively. However, they were less than 2 mm and non-progressive in all cases. The survival rate was 99.4% and there was no implant-related revision. MIS-TKA using a mini-keel modular tibial plate showed satisfactory results, a high survival rate, and excellent clinical and radiological results in the mid-term follow-up.

  5. Minimum 5-year Follow-up Results of Minimally Invasive Total Knee Arthroplasty Using Mini-Keel Modular Tibial Implant

    PubMed Central

    Yoo, Ju-Hyung; Park, Byoung-Kyu; Han, Chang-Dong; Oh, Hyun-Cheol

    2014-01-01

    Purpose To evaluate the minimum 5-year mid-term clinical and radiological results of minimally invasive surgery total knee arthroplasty (MIS-TKA) using a mini-keel modular tibia component. Materials and Methods We retrospectively evaluated 254 patients (361 cases) who underwent MIS-TKA between 2005 and 2006. The latest clinical and radiological assessments were done in 168 cases that had been followed on an outpatient basis for more than 5 postoperative years. Clinical results were assessed using the Hospital for Special Surgery (HSS) score and Knee Society score. Radiological evaluation included measurements of knee alignment. Results The average postoperative knee range of motion and HSS score were 134.3°±12.4° and 92.7°±7.0°, respectively. The average postoperative femorotibial angle and tibial component alignment angle were 5.2°±1.7° valgus and 90.2°±1.6°, respectively. The average tibial component posterior inclination was 4.8°±2.1°. The percentage of cases with tibial component alignment angle of 90°±3° was 96.1%, and that with the femorotibial angle of 6°±3° valgus was 94.0%. Radiolucent lines were observed in 20 cases (12.0%): around the femur, tibia, and patella in 14 cases, 10 cases, and 1 case, respectively. However, they were less than 2 mm and non-progressive in all cases. The survival rate was 99.4% and there was no implant-related revision. Conclusions MIS-TKA using a mini-keel modular tibial plate showed satisfactory results, a high survival rate, and excellent clinical and radiological results in the mid-term follow-up. PMID:25229044

  6. The extensor hallucis longus tendon as the distal reference point in total knee arthroplasty and tibial alignment.

    PubMed

    Bilgen, Omer; Bilgen, Sadık; Ermutlu, Cenk; Göksel, Ferdi; Salar, Necmettin

    2014-01-01

    The aim of this study was to compare the effects on tibial alignment of the use of the extensor hallucis longus (EHL) tendon with the use of the 2nd metatarsal as a reference in total knee arthroplasty (TKA) using the extramedullary technique. The study evaluated 100 postoperative radiographs of 79 patients who underwent primary TKA between 2004 and 2008. Patients were grouped according to the distal anatomical landmark used during surgery. There were 36 patients (mean age: 68.3 years, range: 56 to 82 years) in the EHL-referenced (ERT) group and 43 patients (mean age: 70.2 years, range: 54 to 78 years) in the 2nd metatarsal-referenced (MRT) group. There were 47 components in the ERT group and 53 in the MRT group. Frontal alignments of the tibial components were measured. Angles of 90±2° were accepted as the normal boundaries while those above that value were labeled as 'varus' and those below as 'valgus'. Average frontal alignment was 88.57° in the MRT group and 89.17° in the ERT group. The number of tibial components in the normal range was significantly higher (p=0.017) and the number of varus-oriented components significantly lower (p=0.024) in the ERT group. There were no significant differences in valgus-oriented outliers between groups (p=1.000). The use of the EHL tendon as a reference improves coronal tibial alignment. The EHL is a reliable anatomical landmark to use with extramedullary guide systems.

  7. The accuracy of two different extra-medullary tibial cutting guides for posterior tibial slope in total knee arthroplasty.

    PubMed

    Bek, Doğan; Ege, Tolga; Yıldız, Cemil; Tunay, Servet; Başbozkurt, Mustafa

    2014-01-01

    This study aims to evaluate the effectiveness of two different external tibial cutting guides with and without a spike anchoring to the intercondylar eminentia to achieve a desired posterior tibial slope. Between January 2008 and December 2011, 120 posterior cruciate ligament protecting total knee arthroplasty (TKA) surgeries of 83 patients in which two different external tibial cutting guides used were included. Fifty-nine knees were included into the spiked and 61 knees were included into the spikeless cutting guide group. Posterior tibial slope angles were measured using the postoperative X-rays. There was no significant difference between two groups in terms of age, sex, and body mass indexes (p<0.05). While the mean postoperative slope angle was 2.66°±2.001°(range 0°-7°) in spiked group, it was 2.46°±2.277° (range 0°-7°) in spikeless group. Both systems had identical accuracy, indicating a low rate. The comparison of variances of two groups showed that both cutting guides had similar precision (p=0.234). There was no effect of body mass index on the results in both groups. Although different extra-medullary tibial cutting guides with and without a spike can reproducibly impart a desired posterior tibial slope in TKA, we concluded that a spiked guide was considered user-friendly.

  8. Study of two MTA cements

    PubMed Central

    Valmaseda-Castellón, Eduard; Faus, Vicente; Ballester, María-Luisa; Berini-Aytés, Leonardo

    2014-01-01

    Introduction: To determine and compare the pH, conductivity and calcium release of an experimental Portland cement (PE) consisting of trioxid mineral aggregate and a comercially available modified Portland cement (C.P.M.) after 1, 2, 3, 4, 8, 10, 15 and 30 days. Material and Methods: Cements were mixed following the manufacturer’s instructions, with a powder: liquid ratio of 3:1. Each cement was placed in 12 PVC tubes 1 mm in diameter and 10 mm in length and allowed to set. Four empty tubes were used as negative controls. Tubes were submerged in plastic flasks containing 10 ml deionized water and stored at 37ºC and 100% humidity. After 1, 2, 3, 4, 8, 10, 15 and 30 days tubes were removed from the flasks and these were refilled with deionized water. We measured pH, conductivity and calcium content of the recovered solution. Data were analyzed using repeated measures ANOVA. Results: pH was 0.3 units more alkaline with PE cement (p=0.023). pH experienced a slight decrease with time (p<0.001), independently of the cement type (p>0.05). Conductivity of PE and CPM cements diminished at 4 days and almost recovered at 30 days (p<0.001). PE cement had a higher conductivity (p<0.001). Calcium release diminished from the first day and recovered at 30 days (p<0.001) similarly for both cements (p>0.05). Conclusions: PE cement raised pH slightly more and had higher conductivity than CPM. Calcium release diminished after the first day and recovered at 30 days, similarly for both cements. Key words:Mineral trioxide aggregate, pH, electrical conductivity, periapical surgery. PMID:25350596

  9. Thermal Shock-resistant Cement

    SciTech Connect

    Sugama T.; Pyatina, T.; Gill, S.

    2012-02-01

    We studied the effectiveness of sodium silicate-activated Class F fly ash in improving the thermal shock resistance and in extending the onset of hydration of Secar #80 refractory cement. When the dry mix cement, consisting of Secar #80, Class F fly ash, and sodium silicate, came in contact with water, NaOH derived from the dissolution of sodium silicate preferentially reacted with Class F fly ash, rather than the #80, to dissociate silicate anions from Class F fly ash. Then, these dissociated silicate ions delayed significantly the hydration of #80 possessing a rapid setting behavior. We undertook a multiple heating -water cooling quenching-cycle test to evaluate the cement’s resistance to thermal shock. In one cycle, we heated the 200 and #61616;C-autoclaved cement at 500 and #61616;C for 24 hours, and then the heated cement was rapidly immersed in water at 25 and #61616;C. This cycle was repeated five times. The phase composition of the autoclaved #80/Class F fly ash blend cements comprised four crystalline hydration products, boehmite, katoite, hydrogrossular, and hydroxysodalite, responsible for strengthening cement. After a test of 5-cycle heat-water quenching, we observed three crystalline phase-transformations in this autoclaved cement: boehmite and #61614; and #61543;-Al2O3, katoite and #61614; calcite, and hydroxysodalite and #61614; carbonated sodalite. Among those, the hydroxysodalite and #61614; carbonated sodalite transformation not only played a pivotal role in densifying the cementitious structure and in sustaining the original compressive strength developed after autoclaving, but also offered an improved resistance of the #80 cement to thermal shock. In contrast, autoclaved Class G well cement with and without Class F fly ash and quartz flour failed this cycle test, generating multiple cracks in the cement. The major reason for such impairment was the hydration of lime derived from the dehydroxylation of portlandite formed in the autoclaved

  10. Cementing a wellbore using cementing material encapsulated in a shell

    SciTech Connect

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.

    2017-03-14

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in themore » space between the wellbore and the pipe.« less

  11. Cementing a wellbore using cementing material encapsulated in a shell

    SciTech Connect

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.

    2016-08-16

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in themore » space between the wellbore and the pipe.« less

  12. Optimization and characterization of a cemented ultimate-storage product

    NASA Astrophysics Data System (ADS)

    Brunner, H.

    1981-12-01

    The U- and Pu-containing packaging wastes can be homogeneously cemented after a washing and fragmentation process. Both finely crushed and coarsely fragmented raw wastes yield products with sufficient mechanical stability. The processability limit of the coarsely fragmented raw waste using cement paste or mortar is largely determined by the cellulose content, which is not to exceed 1.3% by weight in the end waste. Of 9 binders studied, the most corrosion-resistant products were obtained with blast-furnace slag cement, whereas poured concrete and Maxit are much less resistant in five-component brine. In the cemented product, hydrolysis of plasticizers (DOP) from plastics (PVC) occurs, leading to release of 2-ethyl-hexanol. This reaction occurs to a much lower degree with blast-furnace slag cement than with all other binders studied. The binder chosen for further tests consists of blast-furnace slag cement, concrete fluidizer and a stabilizer, and is processed at a W/C ratio of 0.43.

  13. Cement manufacture and the environment - Part I: Chemistry and technology

    USGS Publications Warehouse

    Van Oss, H. G.; Padovani, A.C.

    2002-01-01

    Hydraulic (chiefly portland) cement is the binding agent in concrete and mortar and thus a key component of a country's construction sector. Concrete is arguably the most abundant of all manufactured solid materials. Portland cement is made primarily from finely ground clinker, which itself is composed dominantly of hydraulically active calcium silicate minerals formed through high-temperature burning of limestone and other materials in a kiln. This process requires approximately 1.7 tons of raw materials perton of clinker produced and yields about 1 ton of carbon dioxide (CO2) emissions, of which calcination of limestone and the combustion of fuels each contribute about half. The overall level of CO2 output makes the cement industry one of the top two manufacturing industry sources of greenhouse gases; however, in many countries, the cement industry's contribution is a small fraction of that from fossil fuel combustion by power plants and motor vehicles. The nature of clinker and the enormous heat requirements of its manufacture allow the cement industry to consume a wide variety of waste raw materials and fuels, thus providing the opportunity to apply key concepts of industrial ecology, most notably the closing of loops through the use of by-products of other industries (industrial symbiosis). In this article, the chemistry and technology of cement manufacture are summarized. In a forthcoming companion article (part II), some of the environmental challenges and opportunities facing the cement industry are described. Because of the size and scope of the U.S. cement industry, the analysis relies primarily on data and practices from the United States.

  14. Cemented total hip prosthesis: Radiographic and scintigraphic evaluation

    SciTech Connect

    Aliabadi, P.; Tumeh, S.S.; Weissman, B.N.; McNeil, B.J. )

    1989-10-01

    Conventional radiographs, technetium-99m bone scans, and gallium-67 scans were reviewed in 44 patients who had undergone cemented total hip joint replacement and were imaged because of suspicion of prosthesis loosening or infection. A complete radiolucent line of 2 mm or wider along the bone-cement interface or metal-cement lucency on conventional radiographs was used as the criterion for prosthetic loosening with or without infection and proved to be 54% sensitive and 96% specific. Scintigraphic criteria for prosthetic loosening were increased focal uptake of the radiopharmaceutical for the femoral component and increased focal or diffuse uptake for the acetabular component. For bone scintigraphy, sensitivity was 73% and specificity was 96%. Combining the results of conventional radiographs and bone scans increased sensitivity to 84% and decreased specificity to 92% for the diagnosis of loosening, infection, or both. The study also showed that Ga-67 scintigraphy has a low sensitivity for the detection of infection.

  15. Pozzolan cement study : final report.

    DOT National Transportation Integrated Search

    1979-12-01

    An experimental section using Type 1P cement concrete was poured on an active construction project in south Louisiana, near Franklin. A comparison in quality was made between this section and the normal Type 1(B) cement concrete poured on the remaind...

  16. [Thermal diffusivity of dental cements].

    PubMed

    Paroussis, D; Kakaboura, A; Chrysafidis, C; Mauroyiannakis, E

    1990-08-01

    Thermal insulative efficiency, is one of the desirable properties of the dental cements. In this study, the thermal diffusivity of three types of dental cements, were measured. Thermal diffusivity was determined by the following method. Two thermo-couples were used and connected to a chart record, the first was embedded in the cylindrical block of the cement specimen and the other in a mixing of ice and water (reference thermocouple). All them were set in a apparatus consisting of a double cooling bath. Calculation of thermal diffusivity were based on the curve provided of the record during cooling of the cement and a theoretical mathematic model. Values were ranged from 2,985 to 3,934 cm2.sec-1. ZOE cement exhibited the highest value, the glass-ionomers the lowest and the poly-carboxylates were average. The results showed that the thermal diffusivity of the cements is dependent from the type of the cement but the differences between them were not statistically significant. Additionally, the values obtained were about the same as the dentin, so the dental cements may consider as good thermal insulators.

  17. EMG biofeedback assisted KT-1000 evaluation of anterior tibial displacement.

    PubMed

    Feller, J; Hoser, C; Webster, K

    2000-01-01

    Two studies were undertaken to evaluate the use of EMG biofeedback to encourage hamstring relaxation during KT-1000 measurement of anterior tibial displacement. In study 1, 60 ACL-deficient patients were studied in three groups using 15 lb and 20 lb in each group: in group 1 the patients were simply retested 15 min after the initial test sequence, in group 2 they were initially retested with EMG biofeedback and then again without, and in group 3 they were retested twice with EMG biofeedback. No significant difference in mean anterior tibial displacement was seen between the initial measurements and retest measurements when no EMG biofeedback was used. A significant increase in mean anterior tibial displacement was seen when the retesting was performed with EMG biofeedback. No further increase was seen with repeated retesting with EMG biofeedback. In study 2, 40 patients were evaluated 4-12 months following ACL reconstruction. KT-1000 measurements of anterior tibial displacement of both the operated and non-operated knees were made at 15 lb and 30 lb with and without the use of EMG biofeedback. EMG biofeedback was associated with a significant increase in unilateral measurement of anterior tibial displacement. When side-to-side differences were compared, there was a small but statistically significant increase in anterior tibial displacement with the use of EMG biofeedback. Although the use of EMG biofeedback to encourage hamstring relaxation does increase unilateral measurements of anterior tibial displacement, it does not appear to have a clinically significant effect on measurement of side-to-side difference. It may have a role in testing patients who have difficulty achieving hamstring relaxation or in aiding inexperienced examiners.

  18. Alternative method for direct measurement of tibial slope.

    PubMed

    Stijak, Lazar; Santrac-Stijak, Gordana; Spasojević, Goran; Radonjić, Vidosava; Malis, Milos; Milovanović, Darko; Filipović, Branislav

    2014-04-01

    The tibial slope is one of the most frequently cited anatomical causes of anterior cruciate ligament trauma. The aim of this study was to determine the possibility of direct measuring of the tibial slope of the knee without prior soft tissue dissection in cadavers. Measurement was performed on the two groups of samples: osteological and cadaveric. The osteological group consisted of 102 matured tibiae and measurement was performed: indirectly by sagittal photographing of the tibia, and directly by a set of parallel bars. The cadaveric group consisted of 50 cadaveric knees and measurement was performed directly by a set of parallel bars. The difference and correlation between indirect and the direct measurements were observed, which included also measuring of the difference and correlation of the tibial slope on the medial and lateral condyles. A statistically significant difference between the direct and indirect method of measuring (p < 0.01) of 1 degree was found for the tibial slope on the medial condyle, which is of no practical importance. Direct measurement of the osteological and cadaveric groups of samples did not show a statistically significant difference regarding the values of the tibial slope on the lateral condyle (p > 0.05). However, the slope on the medial condyle, as well as indirect measurement showed a statistically significant difference (p < 0.01). By the use of a set of parallel bars it is possible to measure the tibial slope directly without removal of the soft tissue. The results of indirect, photographic measurement did not statistically differ from the results of direct measurement of the tibial slope.

  19. Biomechanical evaluation of tibial bone adaptation after revision total knee arthroplasty: A comparison of different implant systems.

    PubMed

    Quilez, María Paz; Seral, Belen; Pérez, María Angeles

    2017-01-01

    The best methods to manage tibial bone defects following total knee arthroplasty remain under debate. Different fixation systems exist to help surgeons reconstruct knee osseous bone loss (such as tantalum cones, cement, modular metal augments, autografts, allografts and porous metaphyseal sleeves) However, the effects of the various solutions on the long-term outcome remain unknown. In the present work, a bone remodeling mathematical model was used to predict bone remodeling after total knee arthroplasty (TKA) revision. Five different types of prostheses were analyzed: one with a straight stem; two with offset stems, with and without supplements; and two with sleeves, with and without stems. Alterations in tibia bone density distribution and implant Von Mises stresses were quantified. In all cases, the bone density decreased in the proximal epiphysis and medullary channels, and an increase in bone density was predicted in the diaphysis and around stem tips. The highest bone resorption was predicted for the offset prosthesis without the supplement, and the highest bone formation was computed for the straight stem. The highest Von Mises stress was obtained for the straight tibial stem, and the lowest was observed for the stemless metaphyseal sleeves prosthesis. The computational model predicted different behaviors among the five systems. We were able to demonstrate the importance of choosing an adequate revision system and that in silico models may help surgeons choose patient-specific treatments.

  20. Biomechanical evaluation of tibial bone adaptation after revision total knee arthroplasty: A comparison of different implant systems

    PubMed Central

    Quilez, María Paz; Seral, Belen; Pérez, María Angeles

    2017-01-01

    The best methods to manage tibial bone defects following total knee arthroplasty remain under debate. Different fixation systems exist to help surgeons reconstruct knee osseous bone loss (such as tantalum cones, cement, modular metal augments, autografts, allografts and porous metaphyseal sleeves) However, the effects of the various solutions on the long-term outcome remain unknown. In the present work, a bone remodeling mathematical model was used to predict bone remodeling after total knee arthroplasty (TKA) revision. Five different types of prostheses were analyzed: one with a straight stem; two with offset stems, with and without supplements; and two with sleeves, with and without stems. Alterations in tibia bone density distribution and implant Von Mises stresses were quantified. In all cases, the bone density decreased in the proximal epiphysis and medullary channels, and an increase in bone density was predicted in the diaphysis and around stem tips. The highest bone resorption was predicted for the offset prosthesis without the supplement, and the highest bone formation was computed for the straight stem. The highest Von Mises stress was obtained for the straight tibial stem, and the lowest was observed for the stemless metaphyseal sleeves prosthesis. The computational model predicted different behaviors among the five systems. We were able to demonstrate the importance of choosing an adequate revision system and that in silico models may help surgeons choose patient-specific treatments. PMID:28886100

  1. Different changes in slope between the medial and lateral tibial plateau after open-wedge high tibial osteotomy.

    PubMed

    Lustig, S; Scholes, C J; Costa, A J; Coolican, M J; Parker, D A

    2013-01-01

    In contrast to radiographic measurements, MRI provides multiple slices of the knee joint in the sagittal plane, making it possible to assess the medial and lateral tibial slope separately. The purpose of this study is to investigate the effect of medial open-wedge high tibial osteotomy (MOWHTO) on bony and meniscal slope in the medial and lateral tibiofemoral compartments. It was hypothesised that greater changes on the medial tibial plateau would be observed compared with the lateral one. A retrospective analysis of prospectively collected data was performed on pre- and post-operative MRIs from 21 patients (17 men and 4 women; age 52 ± 9 years). Inclusion criteria were varus alignment, medial compartment osteoarthritis and election for a primary MOWHTO. Each patient had a preoperative and a post-operative high-resolution MRI (3Tesla, Magnetom Trio, Siemens AG) at an average follow-up of 2.1 years. A previously published method was used to measure bony and meniscal slope for each compartment. The difference between pre- and post-operative tibial slope for both compartments was calculated and associated with the amount of frontal correction. There was a significant increase in bony tibial slope in both compartments following MOWHTO. When a change in bony tibial slope was detected in an individual patient, the change was larger in the medial compartment, with the average change also significantly greater (p < 0.01) in the medial compartment (2.4° ± 1.3°) compared with the lateral compartment (0.9° ± 1.1°). There was also a significant increase (p < 0.01) in the lateral tibial meniscal slope of 0.9° ± 1.4°, which was equivalent to the change in the bony lateral slope. The amount of frontal correction was not significantly associated with the amount of change in slope. The results suggest that the modification of the bony slope is larger in the medial compartment after MOWHTO, which is likely related to the location of the hinge on the lateral

  2. Fiber reinforced calcium phosphate cement.

    PubMed

    dos Santos, L A; de Oliveira, L C; da Silva Rigo, E C; Carrodéguas, R G; Boschi, A O; Fonseca de Arruda, A C

    2000-03-01

    The term calcium phosphate cement was introduced by Gruninger et al. (1). This type of cement can be prepared by reacting a calcium phosphate salt with an aqueous solution, which causes it to set by the crossing of the precipitated crystals. These cements offer a series of advantages that allow their use as grafts and substitutes of damaged parts of the bone system. However, these cements have low mechanical strength compared to human bones. This work studied the influence of the use of polyamide fibers in the mechanical properties of a calcium phosphate cement based on alpha-tricalcium phosphate as well as the mechanisms involved in the increase of mechanical strength. The results demonstrate the feasibility of the use of polymeric fibers to increase mechanical strength and the need for coupling agents for the effective performance of the fibers as reinforcement in these materials.

  3. New ferromagnetic bone cement for local hyperthermia.

    PubMed

    Takegami, K; Sano, T; Wakabayashi, H; Sonoda, J; Yamazaki, T; Morita, S; Shibuya, T; Uchida, A

    1998-01-01

    We have developed a ferromagnetic bone cement as a thermoseed to generate heat by hysteresis loss under an alternate magnetic field. This material resembles bioactive bone cement in composition, with a portion of the bioactive glass ceramic component replaced by magnetite (Fe3O4) powder. The temperature of this thermoseed rises in proportion to the weight ratio of magnetite powder, the volume of the thermoseed, and the intensity of the magnetic field. The heat-generating ability of this thermoseed implanted into rabbit and human cadaver tibiae was investigated by applying a magnetic field with a maximum of 300 Oe and 100 kHz. In this system, it is very easy to increase the temperature of the thermoseed in bone beyond 50 degrees C by adjusting the above-mentioned control factors. When the temperature of the thermoseed in rabbit tibiae was maintained at 50 to 60 degrees C, the temperature at the interface between the bone and muscle (cortical surface) surrounding the material rose to 43 to 45 degrees C; but at a 10-mm distance from the thermoseed in the medullary canal, the temperature did not exceed 40 degrees C. These results demonstrate that ferromagnetic bone cement may be applicable for the hyperthermic treatment of bone tumors.

  4. Influence of ferrite phase in alite-calcium sulfoaluminate cements

    NASA Astrophysics Data System (ADS)

    Duvallet, Tristana Yvonne Francoise

    Since the energy crisis in 1970's, research on low energy cements with low CO2- emissions has been increasing. Numerous solutions have been investigated, and the goal of this original research is to create a viable hybrid cement with the components of both Ordinary Portland cement (OPC) and calcium sulfoaluminate cement (CSAC), by forming a material that contains both alite and calcium sulfoaluminate clinker phases. Furthermore, this research focuses on keeping the cost of this material reasonable by reducing aluminum requirements through its substitution with iron. The aim of this work would produce a cement that can use large amounts of red mud, which is a plentiful waste material, in place of bauxite known as an expensive raw material. Modified Bogue equations were established and tested to formulate this novel cement with different amounts of ferrite, from 5% to 45% by weight. This was followed by the production of cement from reagent chemicals, and from industrial by-products as feedstocks (fly ash, red mud and slag). Hydration processes, as well as the mechanical properties, of these clinker compositions were studied, along with the addition of gypsum and the impact of a ferric iron complexing additive triisopropanolamine (TIPA). To summarize this research, the influence of the addition of 5-45% by weight of ferrite phase, was examined with the goal of introducing as much red mud as possible in the process without negatively attenuate the cement properties. Based on this PhD dissertation, the production of high-iron alite-calcium sulfoaluminateferrite cements was proven possible from the two sources of raw materials. The hydration processes and the mechanical properties seemed negatively affected by the addition of ferrite, as this phase was not hydrated entirely, even after 6 months of curing. The usage of TIPA counteracted this decline in strength by improving the ferrite hydration and increasing the optimum amount of gypsum required in each composition

  5. 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.

  6. Porous tantalum metaphyseal cones for severe tibial bone loss in revision knee arthroplasty: a five to nine-year follow-up.

    PubMed

    Kamath, Atul F; Lewallen, David G; Hanssen, Arlen D

    2015-02-04

    Severe metaphyseal and meta-diaphyseal bone loss poses important challenges in revision total knee arthroplasty. The best strategy for addressing massive tibial bone loss has not been determined. The purpose of this study was to assess the intermediate-term clinical and radiographic results of porous tibial cone implantation. Sixty-six porous tantalum tibial cones (sixty-three patients) were reviewed at a mean follow-up time of seventy months (range, sixty to 106 months). According to the Anderson Orthopaedic Research Institute bone defect classification, twenty-four knees had a Type-3 defect, twenty-five knees had a Type-2B defect, and seventeen knees had a Type-2A defect. The mean age at the time of the index revision was sixty-seven years (range, forty-one to eighty-three years), and 57% of patients were female. The mean American Society of Anesthesiologists Physical Status was 2.4 (range, 2 to 3), and the mean body mass index was 33 kg/m(2) (range, 25 to 53 kg/m(2)). Fifteen patients (24%) were on immunosuppressant medications, and eight patients (13%) were current smokers. The patients underwent a mean number of 3.4 prior knee surgical procedures (range, one to twenty procedures), and 49% of patients (thirty-one patients) had a history of periprosthetic infection. The mean Knee Society Scores improved significantly from 55 points preoperatively (range, 4 to 97 points) to 80 points (range, 28 to 100 points) at the time of the latest follow-up (p < 0.0001). One patient had progressive radiolucencies about the tibial stem and cone on radiographs. One patient had complete radiolucencies about the tibial cone, concerning for fibrous ingrowth. Three other cones were revised: one for infection, one for aseptic loosening, and one for periprosthetic fracture. Revision-free survival of the tibial cone component was >95% at the time of the latest follow-up. Porous tantalum tibial cones offer a promising management option for severe tibial bone loss. At the intermediate

  7. Femoral and tibial insert downsizing increases the laxity envelope in TKA.

    PubMed

    Mueller, John Kyle P; Wentorf, Fred A; Moore, Richard E

    2014-12-01

    This study examines the effect of component downsizing in a modern total knee arthroplasty (TKA) system on the laxity envelope of the knee throughout flexion. A robotic testing system was utilized to measure laxity envelopes in the implanted knee by in the anterior-posterior (AP), medial-lateral (ML), internal-external (IE) and varus-valgus (VV) directions. Five fresh-frozen cadavers were tested with a modern cruciate retaining TKA implantation, a 1-mm thinner polyethylene insert and a femoral component 2 mm smaller in the AP dimension. The downsized tibial insert was more lax throughout the flexion arc with up to 2.0 mm more laxity in the AP direction at full extension, a 43.8% increase over the original implantation. A thinner insert consistently increased laxity throughout the arc of flexion in all degrees of freedom. Downsizing the femoral component resulted in 8.5 mm increase in AP laxity at 90°, a 73.9% increase. In mid-flexion, downsizing the femur produced similar laxity values to the downsized insert in AP, ML, IE and VV directions. Downsizing the TKA components had significant effects on laxity throughout flexion. Downsizing a femoral component 2 mm had an equivalent increase in laxity in mid-flexion as downsizing the tibial insert 1 mm. This study quantifies the importance of choosing the appropriate implant component size, having the appropriate size available and the effect of downsizing. The laxity of the implanted knee contributes to how the implant feels to the patient and ultimately the patient's satisfaction with their new knee.

  8. 76 FR 76760 - Gray Portland Cement and Cement Clinker From Japan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-08

    ... Portland Cement and Cement Clinker From Japan Determination On the basis of the record \\1\\ developed in the... antidumping duty order on gray Portland cement and cement clinker from Japan would be likely to lead to... the Commission are contained in USITC Publication 4281 (December 2011), entitled Gray Portland Cement...

  9. 21 CFR 888.4200 - Cement dispenser.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cement dispenser. 888.4200 Section 888.4200 Food... DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4200 Cement dispenser. (a) Identification. A cement dispenser is a nonpowered syringe-like device intended for use in placing bone cement (§ 888.3027) into...

  10. 21 CFR 888.4200 - Cement dispenser.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cement dispenser. 888.4200 Section 888.4200 Food... DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4200 Cement dispenser. (a) Identification. A cement dispenser is a nonpowered syringe-like device intended for use in placing bone cement (§ 888.3027) into...

  11. 21 CFR 888.4200 - Cement dispenser.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cement dispenser. 888.4200 Section 888.4200 Food... DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4200 Cement dispenser. (a) Identification. A cement dispenser is a nonpowered syringe-like device intended for use in placing bone cement (§ 888.3027) into...

  12. 21 CFR 888.4200 - Cement dispenser.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cement dispenser. 888.4200 Section 888.4200 Food... DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4200 Cement dispenser. (a) Identification. A cement dispenser is a nonpowered syringe-like device intended for use in placing bone cement (§ 888.3027) into...

  13. 21 CFR 888.4200 - Cement dispenser.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cement dispenser. 888.4200 Section 888.4200 Food... DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4200 Cement dispenser. (a) Identification. A cement dispenser is a nonpowered syringe-like device intended for use in placing bone cement (§ 888.3027) into...

  14. Forefoot flexibility and medial tibial stress syndrome.

    PubMed

    Kudo, Shintarou; Hatanaka, Yasuhiko

    2015-12-01

    To investigate the association between medial tibial stress syndrome (MTSS) and morphology and flexibility of the foot arches. 131 feet from 74 healthy subjects and 31 feet from 27 patients with MTSS were classified as normal feet (n=78 in 40 subjects), flat feet (n=53 in 34 subjects), or MTSS feet (n=31 in 27 patients). The medial longitudinal arch (MLA) ratio and the transverse arch length (TAL) were measured in both rearfoot and forefoot loading positions. The difference between the 2 positions indicated the flexibility of the MLA (diff-MLA ratio) and the transverse arch (diff- TAL). The MLA ratio was higher in normal feet than MTSS feet or flat feet (15.1% vs. 12.8% vs. 12.3%, p<0.001). The diff-TAL was lower in MTSS feet than normal feet or flat feet (0.4% vs. 0.8% vs. 0.9%, p<0.001]). The 3 groups were comparable in terms of the diff-MLA ratio and the TAL. Respectively for the MLA ratio and the diff-TAL, the cut-off value was 11.9% and 0.61% based on the Youden index. The sensitivity, specificity, and odds ratio of the cut-off value were 0.4, 0.9, and 4.8 for the MLA ratio, and 0.6, 0.7, and 9.8 for the diff-TAL, respectively. Decreased flexibility of the transverse arch and decreased MLA ratio are risk factors for MTSS. In contrast, the flexibility of the MLA and the height of the transverse arch were not risk factors for MTSS.

  15. New angle measurement device to control the posterior tibial slope angle in medial opening wedge high tibial osteotomy.

    PubMed

    Ogawa, Hiroyasu; Matsumoto, Kazu; Akiyama, Haruhiko

    2017-11-17

    Medial opening wedge high tibial osteotomy has been associated with an unintentional increase in the posterior tibial slope angle. We aimed to evaluate the effectiveness of a novel bone spreader angle rod to maintain the native posterior tibial slope angle in medial opening wedge high tibial osteotomy. Data from 92 consecutive knees in 83 patients who underwent medial opening wedge high tibial osteotomy for knee osteoarthritis between March 2015 and June 2016 were analysed. The osteotomy was performed without the use of a bone spreader angle rod in the first 50 cases (control group) and with the use of the angle rod in the subsequent 42 cases (angle rod group). The wedge insertion angle, defined as the angle between a line drawn along the posterior aspect of the wedge spacer and a line tangential to the posterior aspect of the femoral condyles, and the posterior tibial slope angle were evaluated on pre- and postoperative lateral knee radiographs and postoperative computed tomography images. Wedge insertion angle showed that wedge spacers were inserted in a more direct horizontal direction in the angle rod group than in the control group (16.0 ± 8.8° and 23.0 ± 10.0°, respectively, P < 0.001). The pre- to postoperative change in posterior tibial slope angle was significantly smaller in the angle rod group (0.6 ± 1.6°) compared to that in the control group (3.2 ± 3.2°; P < 0.0001). A change of posterior tibial slope angle > 3° (outlier) was identified in 1 case (2.4%) in the angle rod group compared to 27 cases in the control group (54.0%). The direct horizontal insertion of wedge spacers with the assistance of our novel bone spreader angle rod maintains the native posterior tibial slope angle better than conventional methods. IV.

  16. Dynamic simulation of tibial tuberosity realignment: model evaluation.

    PubMed

    Purevsuren, Tserenchimed; Elias, John J; Kim, Kyungsoo; Kim, Yoon Hyuk

    2015-01-01

    This study was performed to evaluate a dynamic multibody model developed to characterize the influence of tibial tuberosity realignment procedures on patellofemoral motion and loading. Computational models were created to represent four knees previously tested at 40°, 60°, and 80° of flexion with the tibial tuberosity in a lateral, medial and anteromedial positions. The experimentally loaded muscles, major ligaments of the knee, and patellar tendon were represented. A repeated measures ANOVA with post-hoc testing was performed at each flexion angle to compare data between the three positions of the tibial tuberosity. Significant experimental trends for decreased patella flexion due to tuberosity anteriorization and a decrease in the lateral contact force due to tuberosity medialization were reproduced computationally. The dynamic multibody modeling technique will allow simulation of function for symptomatic knees to identify optimal surgical treatment methods based on parameters related to knee pathology and pre-operative kinematics.

  17. Reduced ultrasound velocity in tibial bone of young ballet dancers.

    PubMed

    Foldes, A J; Danziger, A; Constantini, N; Popovtzer, M M

    1997-05-01

    Young ballet dancers are at risk both for osteopenia, due to low body weight, inadequate nutrition and gonadal dysfunction, as well as for lower limbs stress fractures. However, a direct relationship between stress fractures and bone mass in dancers could not be demonstrated, raising the possibility that qualitative aspects of bone, such as elasticity, may be adversely affected in the dancers. To test this hypothesis, speed of sound, a physical parameter that reflects both quantitative and qualitative properties of bone, was determined at the tibial bone of 27 dance students and 27 non-dance students. The results were compared to bone mineral density at the tibia and the lumbar spine, measured by dual-energy x-ray absorptiometry. All three bone measurements were lower in the dance group, but the difference was statistically significant only for the tibial speed of sound. The role of tibial speed of sound measurement in assessing bone status in athletes warrants further exploration.

  18. Quantitative morphology of the subchondral plate of the tibial plateau.

    PubMed Central

    Milz, S; Putz, R

    1994-01-01

    The object of the present investigation was to measure the thickness distribution of the subchondral plate of the tibial plateau. The data were obtained by computerised image analysis of serial sections. The measured values revealed a marked difference in the thickness between the various regions of the joint surface. Thinner zones (100-300 microns) are found in the peripheral region near the margin of the tibial plateau. Thickness maxima (up to 1500 microns and more) are to be seen at the centres of the joint surfaces. The relationship between the thickness distribution of the subchondral plate and information about the stress distribution of this particular joint surface support the conclusion that the morphology of the subchondral plate of the tibial plateau is determined by the function of the joint. Images Fig. 2 Fig. 3 PMID:7559105

  19. 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... 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...

  20. 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... 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...

  1. 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... 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...

  2. 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... 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...

  3. 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...

  4. Computationally efficient prediction of bone-implant interface micromotion of a cementless tibial tray during gait.

    PubMed

    Fitzpatrick, Clare K; Hemelaar, Pleun; Taylor, Mark

    2014-05-07

    Cementless tibial fixation in total knee replacement (TKR) has potential for improved fixation and ease of revision. Achieving primary stability in cementless TKR is critical to the performance of the components. Excessive micromotion may prevent osseointegration at the bone-implant interface. Computational finite element (FE) studies have been used to predict micromotion at the interface, but analysis of an entire activity cycle is computational expensive, prohibiting large numbers of analyses. Surrogate modeling methods can be used to train a numerical model to predict the response of an FE model. These models are computationally efficient and are suitable for high-volume or iterative analyses requiring probabilistic, statistical or optimization methods. The objective of this work was to train a surrogate model capable of predicting micromotion over the entire bone-implant interface. A proximal tibial bone with mapped material properties was virtually implanted with a tibial tray. A FE model, with six-degree-of-freedom loads sampled from telemetric patients during walking, was used to generate training data for the surrogate model. The linear response surrogate model was evaluated for six full gait cycles; the average and peak micromotion across the interface, and the percentage of bone-implant interface surface area experiencing micromotions less than 50 and greater than 150µm were calculated both as a function of the activity cycle and as the composite peak micromotion throughout the cycle. Differences in root-mean-square (RMS) micromotion between FE and surrogate models were less than 14µm. FE analysis time for a complete gait cycle was 15h, compared to 30s for the surrogate model. Surrogate models have significant potential to rapidly predict micromotion over the entire bone-implant interface, allowing greater range in loading conditions to be explored than is possible through conventional methods. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. 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.

  6. Open-Wedge High Tibial Osteotomy: RCT 2 Years RSA Follow-Up.

    PubMed

    Lind-Hansen, Thomas Bruno; Lind, Martin Carøe; Nielsen, Poul Torben; Laursen, Mogens Berg

    2016-11-01

    We investigated the influence of three different bone grafting materials on stability and clinical outcome of the healing open-wedge high tibial osteotomy (OW-HTO) with immediate partial weight bearing. A total of 45 (3 × 15) patients were randomized to injectable calcium phosphate cement (Calcibon; Biomet-Merck Biomaterials GmbH, Darmstadt, Germany), local bone autograft, or iliac crest autograft. Stability of the bony healing was evaluated with radiostereometric analysis (RSA) up to 24 months postoperatively. Clinical outcome was evaluated with the knee injury and osteoarthritis outcome score (KOOS). RSA revealed translations and rotations close to zero regardless of bone grafting material, with no statistically significant differences between the groups. Clinically, the Calcibon group had lower quality of life KOOS subscore at 2 years follow-up. We conclude that with a stable implant and 6 weeks of partial weight bearing, local autografting is sufficient to achieve solid bone consolidation following OW-HTO. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  7. Thermodynamic and structural characteristics of cement minerals at elevated temperature

    SciTech Connect

    Bruton, C.J.; Meike, A.; Viani, B.E.

    1994-05-01

    We have instituted an experimental and including program designed to elucidate the structural and thermodynamic response of cement minerals to elevated temperature. Components of the program involve: (a) synthesis of hydrated Ca-silicates; (b) structural analysis of cement phases induced by heating and dehydration/rehydration; (c) mechanistic and thermodynamic descriptions of the hydration/dehydration behavior of hydrated Ca-silicates as a function of temperature, pressure and relative humidity; (d) study of naturally occurring hydrated Ca-silicates; and (e) measurements of thermodynamic data for hydrated Ca-silicates.

  8. Pes Anserinus Bursitis due to Tibial Spurs in Children.

    PubMed

    Tiwari, Vivek; Sampath Kumar, Venkatesan; Poudel, Rishi R; Kumar, Ashok; Khan, Shah Alam

    2017-07-05

    Osteochondromas are the most common bone tumours. Although these tumors are relatively common in the long bones of children, the varied clinical and radiographic presentation of such neoplasms around the knee joint can cause diagnostic delays, especially when not associated with a palpable swelling. Proximal tibial osteochondromas can sometimes unusually present as spurs/ rose thorns leading to pes anserinus bursitis and vague knee pain. We describe the clinico-radiographic features of such proximal tibial metaphyseal osteochondromas giving rise to pes anserinus bursitis in three children, including bilaterally symmetrical osteochondroma in one of the cases, who were treated conservatively with good outcomes.

  9. Radiological analysis of closed-wedge high tibial osteotomy.

    PubMed

    Turgut, Ali; Kayali, Cemil; Ağuş, Haluk

    2012-01-01

    In this study, we aimed to evaluate changes in frontal plane (anatomical axis) and sagittal plane (tibial slope, patellar height) parameters following closed-wedge high tibial osteotomy (HTO) and possible correlations between them. Between June 2003 and May 2007, 15 knees of the 13 female patients (mean age 52.6 years; range 45 to 64 years) who were followed on a regular basis in our outpatient clinic and underwent closed-wedge HTO were included. The mean follow-up was 49 months (range 29-75 months). Radiologic analysis was performed using pre- and postoperative anatomical axis, tibial slope, and patellar height measurements [Caton index (CI) and Insall-Salvati index (ISI)]. The findings were analyzed by using Wilcoxon matched pairs test and Pearson's correlation test. Preoperative varus deformity was 6.3° ± 2.7°, while it was measured as 7.2° ± 2.5° valgus in the last visit (p=0.0004). The pre- and postoperative CI were 0.97 ± 0.1 and 0.96 ± 0.1, respectively (p=0.85). The ISI decreased from 1.23 ± 0.15 to 1.14 ± 0.15 (p=0.012). Patella baja was observed in only one patient (ISI=0.77). Preoperatively tibial slope was 6.5° ± 2.4°, while it was measured as 0.06° ± 3.4° in the last visit (p=0.0001). There was no correlation between frontal plane angle change and tibial slope, also between patellar height and tibial slope. Closed-wedge HTO does not result in significant changes in patellar height. The risk of patella baja can be decreased through minimal dissection around patellar tendon. However, closed-wedge HTO reduces tibial slope significantly. Optimal resection from posterior tibia is necessary to prevent this condition. A possible loss of tibial slope should be considered in the further reconstructive procedures.

  10. [Metal/alumine metallosis on tibial osteotomy. A case report].

    PubMed

    Mathieu, G; Roue, J; Poignard, A; Hernigou, P

    2008-05-01

    Metallosis is mainly described in the hip joint at the time of wear or inappropriate use. Cases have also been reported in patients with a knee prosthesis, but never after tibial osteotomy. We report a rare case of metallosis resulting from metal-alumina contact after open wedge tibial osteotomy. The patient complained of pain, which was relieved after removal of the plate nine months after the first operation. Intraoperative inspection revealed metallosis at the synthesis site and local plate wear at zone of contact with the ceramic filler. Removal of the plate and cleaning of the metallosis zone led to full relief of the pain at one and a half months.

  11. An accessory portal for posterior cruciate ligament tibial insertion visualization.

    PubMed

    Bach, Bernard R; Aadalen, Kirk J; Mazzocca, Augustus D

    2004-07-01

    Posterior cruciate ligament (PCL) reconstruction is infrequently performed, technically challenging, and has less predictable results compared with its anterior cruciate ligament (ACL) counterpart. Creation of a transtibial tunnel has been associated with catastrophic neurovascular complications, as well as tunnel malpositioning. This technical note reports the use of the femoral PCL tunnel to visually access the posterior slope for tibial tunnel creation. This technique modification allows concurrent placement of instruments through an inferomedial and/or posteromedial portal to facilitate PCL insertional debridement, placement of the tibial aimer, and creation of the tunnel. We feel that this technical modification provides superior visualization of this anatomic area.

  12. Tibial shaft anatomy differs between Caucasians and East Asian individuals.

    PubMed

    Shao, Hongyi; Chen, Chilung; Scholl, Daniel; Faizan, Ahmad; Chen, Antonia F

    2017-09-22

    The orientation and distance from the shaft of the femur and tibia to the articular surface centre is important for performing total knee arthroplasty (TKA) with cementless stems. It is important to understand anatomic differences between races to match the tibial and femoral shaft axis to the knee articular surface. Thus, the purpose of this study was to compare knee morphology between Caucasian and East Asian individuals to determine the optimal placement of tibial and femoral stems. A retrospective study was conducted on a matched cohort of 50 East Asians (21F, 29M) and 50 Caucasians (21F, 29M) by age and gender. CT scans were obtained in healthy volunteers using < 2-mm slices. The distance from the proximal tibial diaphysis axis to the tibial plateau centre and the distance from the distal femoral diaphysis axis to the centre of distal femoral articular surface were measured separately. Tibial measurements were taken using Akagi's anteroposterior (AP) axis and the widest mediolateral (ML) diameter, and femoral measurements were based on Whiteside's line and the surgical epicondylar axis. The ML distance between the tibial shaft centre and Akagi's line was significantly higher for Asians (9.9 ± 2.7 mm, Caucasians 7.7 ± 3.1 mm, p < 0.001). The distance between the femoral shaft centre and Whiteside's line was lower, although not significantly different (Asians 1.9 ± 1.0 mm, Caucasians 2.2 ± 1.1 mm, n.s.). However, there were no differences in the AP dimension for the femur or tibia comparing Asians to Caucasians in both tibial side (Asians 10.6 ± 3.3 mm vs. Caucasians 10.9 ± 4.0 mm) and femoral side (Asians 18.1 ± 1.7 mm vs. Caucasians 17.5 ± 1.6 mm). East Asian individuals have more offset in the ML dimension for the tibia. This finding is clinical relevant, as this dimensional difference should be taken into consideration when designing primary and revision TKA stemmed tibial implants for East Asian individuals. Case

  13. PORTLAND CEMENT CONCRETE FOR ANTARCTICA.

    DTIC Science & Technology

    formulation of recommended procedures for batching, mixing, placing, and curing of portland cement concrete in Antarctica. The pertinent features of the mix and design and related procedures are given. (Author)

  14. Graphite-reinforced bone cement

    NASA Technical Reports Server (NTRS)

    Knoell, A. C.

    1976-01-01

    Chopped graphite fibers added to surgical bone cement form bonding agent with mechanical properties closely matched to those of bone. Curing reaction produces less heat, resulting in reduced traumatization of body tissues. Stiffness is increased without affecting flexural strength.

  15. Increased medial tibial slope in teenage pediatric population with open physes and anterior cruciate ligament injuries.

    PubMed

    Vyas, Shail; van Eck, Carola F; Vyas, Nina; Fu, Freddie H; Otsuka, Norman Y

    2011-03-01

    Variations in bony morphology have been associated with anterior cruciate ligament (ACL) injury risk. The primary aim of this study was to compare the tibial slope in the teenage pediatric population with open physes, with and without ACL injury. The secondary aims were to compare the notch width index (NWI) and determine the influence of gender and age on tibial slope and NWI. Thirty-nine teenage pediatric subjects were included in this study, 16 with and 23 without ACL injury. Medial tibial slope and lateral tibial slope and NWI as measured on plain radiographs were compared between the groups using an independent t-test. Comparison of tibial slope and NWI was also performed between male and female subjects. Pearson correlation coefficient between age and tibial slope and NWI was calculated. The medial tibial slope averaged 10.2 (±3.9) degrees, the lateral tibial slope 11.5 (±3.9) degrees, and the NWI 0.26. There was a significant difference in medial tibial slope between the ACL-injured (12.1 degrees) subjects and the controls (8.9 degrees) (P = 0.009). There was no significant difference in lateral tibial slope or NWI between the groups. There was no significant difference in the medial tibial slope and lateral tibial slope and NWI between the male and female subjects. Subject age was not correlated with medial tibial slope and lateral tibial slope or NWI. There was an increased medial tibial slope in ACL-injured teenagers with open physes, when compared to a control group of teenager with open physes without ACL injury.

  16. Co-contraction patterns of trans-tibial amputee ankle and knee musculature during gait

    PubMed Central

    2012-01-01

    Background Myoelectric control of upper extremity powered prostheses has been used clinically for many years, however this approach has not been fully developed for lower extremity prosthetic devices. With the advent of powered lower extremity prosthetic components, the potential role of myoelectric control systems is of increasing importance. An understanding of muscle activation patterns and their relationship to functional ambulation is a vital step in the future development of myoelectric control. Unusual knee muscle co-contractions have been reported in both limbs of trans-tibial amputees. It is currently unknown what differences exist in co-contraction between trans-tibial amputees and controls. This study compares the activation and co-contraction patterns of the ankle and knee musculature of trans-tibial amputees (intact and residual limbs), and able-bodied control subjects during three speeds of gait. It was hypothesized that residual limbs would have greater ankle muscle co-contraction than intact and able-bodied control limbs and that knee muscle co-contraction would be different among all limbs. Lastly it was hypothesized that the extent of muscle co-contraction would increase with walking speed. Methods Nine unilateral traumatic trans-tibial amputees and five matched controls participated. Surface electromyography recorded activation from the Tibialis Anterior, Medial Gastrocnemius, Vastus Lateralis and Biceps Femoris of the residual, intact and control limbs. A series of filters were applied to the signal to obtain a linear envelope of the activation patterns. A co-contraction area (ratio of the integrated agonist and antagonist activity) was calculated during specific phases of gait. Results Co-contraction of the ankle muscles was greater in the residual limb than in the intact and control limbs during all phases of gait. Knee muscle co-contraction was greater in the residual limb than in the control limb during all phases of gait. Conclusion Co

  17. Properties of acrylic bone cements formulated with Bis-GMA.

    PubMed

    Vallo, Claudia I; Schroeder, Walter F

    2005-08-01

    Experimental cement formulations were prepared by replacing part of the methylmethacrylate (MMA) liquid phase of a conventional surgical cement with an equivalent weight of 2,2-bis [4(2-hydroxy-3-methacryloxypropoxy) phenyl] propane (Bis-GMA), which is the reaction product of diglycidyl ether of bisphenol A and methacrylic acid. It was found that up to 50 wt % of the MMA could be replaced by Bis-GMA without reductions in flow characteristics of the precured polymers. Cements containing 20, 30, 40, and 50 wt % of Bis-GMA in the liquid component were prepared. Over this range of Bis-GMA wt %, it was found that, relative to the unmodified cement, the volumetric shrinkage (DV), the peak temperature reached during the polymerization reaction (Tp), and the flexural strength (obtained in three-point bend tests) were each significantly reduced, the flexural modulus (obtained in three-point bend tests) increased significantly, the compressive strength increased slightly, while there were no significant effects on any of the other properties determined, namely, degree of conversion of the monomer during the polymerization reaction and the glass transition temperature. The drops in D(V) and Tp indicate that cements whose liquid monomers are modified using Bis-GMA hold promise for use in anchoring total joint replacements. The increase in the crosslinking density with increasing amount of Bis-GMA renders the polymer matrix more brittle. This feature was considered responsible for the reduced flexural strength. Copyright 2005 Wiley Periodicals, Inc.

  18. Castable cements to prevent corrosion of metals in molten salts

    SciTech Connect

    Gomez-Vidal, Judith C.; Morton, E.

    2016-04-22

    Castable cements on metals form a protective barrier that is able to prevent permeation of molten salts towards metallic surfaces. Silica-based castable cements are capable of protecting containment metallic alloys from the corrosive attack of molten chlorides at temperatures as high as 650 °C. Boron nitride (BN) blocking the pores in the cured cement prevents permeation of the molten chloride towards the metal surface. The cements tested are not chemically stable in molten carbonates, because the bonding components dissolved into molten carbonates salt. The corrosion rate is 7.72±0.32 mm/year for bare stainless steel 347 in molten eutectic NaCl – 65.58more » wt% LiCl at 650 °C, which is the baseline used for determining how well the cement protects the metallic surfaces from corrosion. In particular the metal fully encapsulated with Aremco 645-N with pores filled with boron nitride immersed in molten eutectic NaCl – 65.58 wt% LiCl at 650 °C shows a corrosion rate of 9E-04 mm/year. Here, the present study gives initial corrosion rates. Long-term tests are required to determine if Aremco 645-N with BN coating on metal has long term chemical stability for blocking salt permeation through coating pores.« less

  19. Enhanced bioactivity of glass ionomer cement by incorporating calcium silicates

    PubMed Central

    Chen, Song; Cai, Yixiao; Engqvist, Håkan; Xia, Wei

    2016-01-01

    Abstract Glass ionomer cements (GIC) are known as a non-bioactive dental cement. During setting the GIC have an acidic pH, driven by the acrylic acid component. It is a challenge to make GIC alkaline without disturbing its mechanical properties. One strategy was to add slowly reacting systems with an alkaline pH. The aim of the present study is to investigate the possibility of forming a bioactive dental material based on the combination of glass ionomer cement and calcium silicates. Two types of GIC were used as control. Wollastonite (CS also denoted β-CaSiO3) or Mineral Trioxide Aggregate (MTA) was incorporated into the 2 types of GIC. The material formulations’ setting time, compressive strength, pH and bioactivity were compared between modified GIC and GIC control. Apatite crystals were found on the surfaces of the modified cements but not on the control GIC. The compressive strength of the cement remained with the addition of 20% calcium silicate or 20% MTA after one day immersion. In addition, the compressive strength of GIC modified with 20% MTA had been increased during the 14 d immersion (p < 0 .05). PMID:26787304

  20. Enhanced bioactivity of glass ionomer cement by incorporating calcium silicates.

    PubMed

    Chen, Song; Cai, Yixiao; Engqvist, Håkan; Xia, Wei

    2016-01-01

    Glass ionomer cements (GIC) are known as a non-bioactive dental cement. During setting the GIC have an acidic pH, driven by the acrylic acid component. It is a challenge to make GIC alkaline without disturbing its mechanical properties. One strategy was to add slowly reacting systems with an alkaline pH. The aim of the present study is to investigate the possibility of forming a bioactive dental material based on the combination of glass ionomer cement and calcium silicates. Two types of GIC were used as control. Wollastonite (CS also denoted β-CaSiO3) or Mineral Trioxide Aggregate (MTA) was incorporated into the 2 types of GIC. The material formulations' setting time, compressive strength, pH and bioactivity were compared between modified GIC and GIC control. Apatite crystals were found on the surfaces of the modified cements but not on the control GIC. The compressive strength of the cement remained with the addition of 20% calcium silicate or 20% MTA after one day immersion. In addition, the compressive strength of GIC modified with 20% MTA had been increased during the 14 d immersion (p < 0 .05).

  1. Utilization of Palm Oil Clinker as Cement Replacement Material

    PubMed Central

    Kanadasan, Jegathish; Abdul Razak, Hashim

    2015-01-01

    The utilization of waste materials from the palm oil industry provides immense benefit to various sectors of the construction industry. Palm oil clinker is a by-product from the processing stages of palm oil goods. Channelling this waste material into the building industry helps to promote sustainability besides overcoming waste disposal problems. Environmental pollution due to inappropriate waste management system can also be drastically reduced. In this study, cement was substituted with palm oil clinker powder as a binder material in self-compacting mortar. The fresh, hardened and microstructure properties were evaluated throughout this study. In addition, sustainability component analysis was also carried out to assess the environmental impact of introducing palm oil clinker powder as a replacement material for cement. It can be inferred that approximately 3.3% of cement production can be saved by substituting palm oil clinker powder with cement. Reducing the utilization of cement through a high substitution level of this waste material will also help to reduce carbon emissions by 52%. A cleaner environment free from pollutants can be created to ensure healthier living. Certain industries may benefit through the inclusion of this waste material as the cost and energy consumption of the product can be minimized. PMID:28793748

  2. Utilization of Palm Oil Clinker as Cement Replacement Material.

    PubMed

    Kanadasan, Jegathish; Abdul Razak, Hashim

    2015-12-16

    The utilization of waste materials from the palm oil industry provides immense benefit to various sectors of the construction industry. Palm oil clinker is a by-product from the processing stages of palm oil goods. Channelling this waste material into the building industry helps to promote sustainability besides overcoming waste disposal problems. Environmental pollution due to inappropriate waste management system can also be drastically reduced. In this study, cement was substituted with palm oil clinker powder as a binder material in self-compacting mortar. The fresh, hardened and microstructure properties were evaluated throughout this study. In addition, sustainability component analysis was also carried out to assess the environmental impact of introducing palm oil clinker powder as a replacement material for cement. It can be inferred that approximately 3.3% of cement production can be saved by substituting palm oil clinker powder with cement. Reducing the utilization of cement through a high substitution level of this waste material will also help to reduce carbon emissions by 52%. A cleaner environment free from pollutants can be created to ensure healthier living. Certain industries may benefit through the inclusion of this waste material as the cost and energy consumption of the product can be minimized.

  3. Castable cements to prevent corrosion of metals in molten salts

    SciTech Connect

    Gomez-Vidal, Judith C.; Morton, E.

    2016-04-22

    Castable cements on metals form a protective barrier that is able to prevent permeation of molten salts towards metallic surfaces. Silica-based castable cements are capable of protecting containment metallic alloys from the corrosive attack of molten chlorides at temperatures as high as 650 °C. Boron nitride (BN) blocking the pores in the cured cement prevents permeation of the molten chloride towards the metal surface. The cements tested are not chemically stable in molten carbonates, because the bonding components dissolved into molten carbonates salt. The corrosion rate is 7.72±0.32 mm/year for bare stainless steel 347 in molten eutectic NaCl – 65.58 wt% LiCl at 650 °C, which is the baseline used for determining how well the cement protects the metallic surfaces from corrosion. In particular the metal fully encapsulated with Aremco 645-N with pores filled with boron nitride immersed in molten eutectic NaCl – 65.58 wt% LiCl at 650 °C shows a corrosion rate of 9E-04 mm/year. Here, the present study gives initial corrosion rates. Long-term tests are required to determine if Aremco 645-N with BN coating on metal has long term chemical stability for blocking salt permeation through coating pores.

  4. Calcium Orthophosphate Cements and Concretes

    PubMed Central

    Dorozhkin, Sergey V.

    2009-01-01

    In early 1980s, researchers discovered self-setting calcium orthophosphate cements, which are a bioactive and biodegradable grafting material in the form of a powder and a liquid. Both phases form after mixing a viscous paste that after being implanted, sets and hardens within the body as either a non-stoichiometric calcium deficient hydroxyapatite (CDHA) or brushite, sometimes blended with unreacted particles and other phases. As both CDHA and brushite are remarkably biocompartible and bioresorbable (therefore, in vivo they can be replaced with newly forming bone), calcium orthophosphate cements represent a good correction technique for non-weight-bearing bone fractures or defects and appear to be very promising materials for bone grafting applications. Besides, these cements possess an excellent osteoconductivity, molding capabilities and easy manipulation. Furthermore, reinforced cement formulations are available, which in a certain sense might be described as calcium orthophosphate concretes. The concepts established by calcium orthophosphate cement pioneers in the early 1980s were used as a platform to initiate a new generation of bone substitute materials for commercialization. Since then, advances have been made in the composition, performance and manufacturing; several beneficial formulations have already been introduced as a result. Many other compositions are in experimental stages. In this review, an insight into calcium orthophosphate cements and concretes, as excellent biomaterials suitable for both dental and bone grafting application, has been provided.

  5. Accuracy assessment of measuring component position after total ankle arthroplasty using a conventional method.

    PubMed

    Lee, Kyoung-Jai; Wang, Shao-Hua; Lee, Gun-Woo; Lee, Keun-Bae

    2017-07-31

    This study was to assess the accuracy of measuring the tibial and talar components position and to investigate the outlier rate of each component and predisposing factors related to component malalignment after total ankle arthroplasty (TAA) using a conventional method. One hundred fifty consecutive primary total ankle arthroplasty were performed using the three-component HINTEGRA prosthesis for ankle end-stage osteoarthritis. Radiographic analysis for the accuracy of component position in coronal and sagittal plane was conducted at postoperative 6 months. Additionally, the accuracy of component position was evaluated according to presence of preoperative deformity or joint incongruency. The mean postoperative coronal angles of the tibial and talar components (α and γ) were 91.9° and 91.3°. The mean postoperative sagittal angles of the tibial and talar components (β and δ angle) were 84.6° and 91.7°. In the coronal plane, 16 (10.7%) tibial components and 15 (10.0%) talar components showed outliers greater than 5°. In sagittal plane, 15 (10.0%) tibial components and 29 (19.3%) talar components showed outliers greater than 5°. There was no meaningful increase of the outlier rate regarding presence of preoperative deformity or joint incongruency. In conventional method of TAA, the outlier rate of the tibial and talar components was about 10 to 20%, especially, the outlier rate of talar component in sagittal plane was up to 20%. Therefore, careful attention should be paid to implant the talar component in conventional TAA.

  6. Durability of Cement Composites Reinforced with Sisal Fiber

    NASA Astrophysics Data System (ADS)

    Wei, Jianqiang

    This dissertation focuses mainly on investigating the aging mechanisms and degradation kinetics of sisal fiber, as well as the approaches to mitigate its degradation in the matrix of cement composites. In contrast to previous works reported in the literature, a novel approach is proposed in this study to directly determine the fiber's degradation rate by separately studying the composition changes, mechanical and physical properties of the embedded sisal fibers. Cement hydration is presented to be a crucial factor in understanding fiber degradation behavior. The degradation mechanisms of natural fiber consist of mineralization of cell walls, alkali hydrolysis of lignin and hemicellulose, as well as the cellulose decomposition which includes stripping of cellulose microfibrils and alkaline hydrolysis of amorphous regions in cellulose chains. Two mineralization mechanisms, CH-mineralization and self-mineralization, are proposed. The degradation kinetics of sisal fiber in the cement matrix are also analyzed and a model to predict the degradation rate of cellulose for natural fiber embedded in cement is outlined. The results indicate that the time needed to completely degrade the cellulose in the matrix with cement replacement by 30wt.% metakaolin is 13 times longer than that in pure cement. A novel and scientific method is presented to determine accelerated aging conditions, and to evaluating sisal fiber's degradation rate and durability of natural fiber-reinforced cement composites. Among the static aggressive environments, the most effective approach for accelerating the degradation of natural fiber in cement composites is to soak the samples or change the humidity at 70 °C and higher temperature. However, the dynamic wetting and drying cycling treatment has a more accelerating effect on the alkali hydrolysis of fiber's amorphous components evidenced by the highest crystallinity indices, minimum content of holocellulose, and lowest tensile strength. Based on the

  7. Selection of materials for post cementation.

    PubMed

    Mitchell, C A

    2000-09-01

    Many types of cement are available for post cementation, each with advantages and disadvantages. For posts with adequate mechanical retention, zinc phosphate is a good choice for patients for whom fluoride release is not considered essential. Posts with compromised mechanical retention benefit from use of a resin-modified glass-ionomer cement, which also releases fluoride. Composite resin cements should be reserved for rare cases where mechanical retention is so compromised that use of a resin-modified glass-ionomer cement provides inadequate retention. Great care is required when using composite resin cements to ensure optimum performance and avoid the creation of difficult-to-remove excess cement. Clinicians should be aware that posts cemented with resin-modified glass ionomer or composite resin cements may be difficult or impossible to remove if access to the root canal system is subsequently required.

  8. Effect of sepiolite on the flocculation of suspensions of fibre-reinforced cement

    SciTech Connect

    Jarabo, Rocio; Fuente, Elena; Moral, Ana; Blanco, Angeles; Negro, Carlos

    2010-10-15

    Sepiolite is used to increase thixotropy of cement slurries for easier processing, to prevent sagging and to provide a better final quality in the manufacture of fibre-reinforced cement products. However, the effect of sepiolite on flocculation and its interactions with the components of fibre cement are yet unknown. The aim of this research is to study the effects of sepiolite on the flocculation of different fibre-reinforced cement slurries induced by anionic polyacrylamides (A-PAMs). Flocculation and floc properties were studied by monitoring the chord size distribution in real time employing a focused beam reflectance measurement (FBRM) probe. The results show that sepiolite increases floc size and floc stability in fibre-cement suspensions. Sepiolite competes with fibres and clay for A-PAMs adsorption and its interaction with A-PAM improves flocculation of mineral particles.

  9. Effect of sepiolite on the flocculation of suspensions of fibre-reinforced cement

    SciTech Connect

    Jarabo, Rocio; Fuente, Elena; Moral, Ana

    2010-10-15

    Sepiolite is used to increase thixotropy of cement slurries for easier processing, to prevent sagging and to provide a better final quality in the manufacture of fibre-reinforced cement products. However, the effect of sepiolite on flocculation and its interactions with the components of fibre cement are yet unknown. The aim of this research is to study the effects of sepiolite on the flocculation of different fibre-reinforced cement slurries induced by anionic polyacrylamides (A-PAMs). Flocculation and floc properties were studied by monitoring the chord size distribution in real time employing a focused beam reflectance measurement (FBRM) probe. The results show thatmore » sepiolite increases floc size and floc stability in fibre-cement suspensions. Sepiolite competes with fibres and clay for A-PAMs adsorption and its interaction with A-PAM improves flocculation of mineral particles.« less

  10. Shelf life and in vivo duration. Impacts on performance of tibial bearings.

    PubMed

    Currier, B H; Currier, J H; Collier, J P; Mayor, M B; Scott, R D

    1997-09-01

    Polyethylene has been used for more than 30 years as an orthopaedic bearing material; however, recently concern has been focused on the early failure of some polyethylene bearings. The damage seen in some bearings has been linked to gamma radiation sterilization performed in an air environment. Gamma sterilization in air has been documented to cause an increase in oxidation and degradation of mechanical properties that continue with time. However, not all retrieved bearings that are gamma sterilized in air exhibit the elevated oxidation and mechanical property degradation that lead to early component failure. Bearings that are gamma sterilized in air oxidize while sitting in inventory before implantation. Shelf oxidation rate was estimated based on analysis of a series of never implanted tibial bearings. This shelf oxidation rate allowed estimation of in vivo oxidation for retrieved tibial bearings of known sterilization date. Bearings with less than 1 year of shelf life after gamma sterilization in air had lower in vivo oxidation and better in vivo performance than did those with longer shelf life before implantation. Shelf time before implantation appears to be a significant factor in the success or failure of bearings that are gamma sterilized in air.

  11. Changes in cardiac output and tibial artery flow during and after progressive LBNP

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A 3.0 MHz Pulsed Doppler velocity meter (PD) was used to determine blood velocities in the ascending aorta from the suprasternal notch before, during and after progressive 5 min stages of lower body negative pressure (LBNP) in 7 subjects. Changes in stroke volume were calculated from the systolic velocity integrals. A unique 20 MHz PD was used to estimate bloodflow in the posterior tibial artery. With -20 torr mean stroke volume fell 11% and then continued to decline by 48% before LBNP was terminated. Mean tibial flow fell progressively with LBNP stress, due to an increase in reverse flow component and a reduction in peak forward flow and diameter. Stroke volume increased and heart rate fell dramatically during the first 15 sec of recovery. The LBNP was terminated early in 2 subjects because of vasovagal symptons (V). During V the stroke volume rose 86% which more than compensated for the drop in heart rate. This implies that V is accompanied by a paradoxical increase in venous return and that the reduction in HR is the primary cardiovascular event. During the first 15 sec of recovery these 2 subjects had a distinctive marked rise to heart rate reminiscent of the Bainbridge reflex.

  12. Multi-Elemental Profiling of Tibial and Maxillary Trabecular Bone in Ovariectomised Rats

    PubMed Central

    Han, Pingping; Lu, Shifeier; Zhou, Yinghong; Moromizato, Karine; Du, Zhibin; Friis, Thor; Xiao, Yin

    2016-01-01

    Atomic minerals are the smallest components of bone and the content of Ca, being the most abundant mineral in bone, correlates strongly with the risk of osteoporosis. Postmenopausal women have a far greater risk of suffering from OP due to low Ca concentrations in their bones and this is associated with low bone mass and higher bone fracture rates. However, bone strength is determined not only by Ca level, but also a number of metallic and non-metallic elements in bone. Thus, in this study, the difference of metallic and non-metallic elements in ovariectomy-induced osteoporosis tibial and maxillary trabecular bone was investigated in comparison with sham operated normal bone by laser ablation inductively-coupled plasma mass spectrometry using a rat model. The results demonstrated that the average concentrations of 25Mg, 28Si, 39K, 47Ti, 56Fe, 59Co, 77Se, 88Sr, 137Ba, and 208Pb were generally higher in tibia than those in maxilla. Compared with the sham group, Ovariectomy induced more significant changes of these elements in tibia than maxilla, indicating tibial trabecular bones are more sensitive to changes of circulating estrogen. In addition, the concentrations of 28Si, 77Se, 208Pb, and Ca/P ratios were higher in tibia and maxilla in ovariectomised rats than those in normal bone at all time-points. The present study indicates that ovariectomy could significantly impact the element distribution and concentrations between tibia and maxilla. PMID:27338361

  13. Multi-Elemental Profiling of Tibial and Maxillary Trabecular Bone in Ovariectomised Rats.

    PubMed

    Han, Pingping; Lu, Shifeier; Zhou, Yinghong; Moromizato, Karine; Du, Zhibin; Friis, Thor; Xiao, Yin

    2016-06-21

    Atomic minerals are the smallest components of bone and the content of Ca, being the most abundant mineral in bone, correlates strongly with the risk of osteoporosis. Postmenopausal women have a far greater risk of suffering from OP due to low Ca concentrations in their bones and this is associated with low bone mass and higher bone fracture rates. However, bone strength is determined not only by Ca level, but also a number of metallic and non-metallic elements in bone. Thus, in this study, the difference of metallic and non-metallic elements in ovariectomy-induced osteoporosis tibial and maxillary trabecular bone was investigated in comparison with sham operated normal bone by laser ablation inductively-coupled plasma mass spectrometry using a rat model. The results demonstrated that the average concentrations of (25)Mg, (28)Si, (39)K, (47)Ti, (56)Fe, (59)Co, (77)Se, (88)Sr, (137)Ba, and (208)Pb were generally higher in tibia than those in maxilla. Compared with the sham group, Ovariectomy induced more significant changes of these elements in tibia than maxilla, indicating tibial trabecular bones are more sensitive to changes of circulating estrogen. In addition, the concentrations of (28)Si, (77)Se, (208)Pb, and Ca/P ratios were higher in tibia and maxilla in ovariectomised rats than those in normal bone at all time-points. The present study indicates that ovariectomy could significantly impact the element distribution and concentrations between tibia and maxilla.

  14. Impact of Axial Component Alignment in Total Knee Arthroplasty on Lower Limb Rotational Alignment: An In Vitro Study.

    PubMed

    Maderbacher, Guenther; Baier, Clemens; Springorum, Hans-Robert; Maderbacher, Hermann; Birkenbach, Anne-Maria; Benditz, Achim; Grifka, Joachim; Keshmiri, Armin

    2017-05-01

    Correct rotational implant alignment is associated with increased postoperative function and implant survival in total knee arthroplasty (TKA). Due to conformity between tibial and femoral implants, particularly in full extension, we assumed a mutual interference of femoral and tibial component rotations. We, therefore, hypothesized that different rotational alignments of the tibial or femoral components change the rotational postures between the tibia and femur after TKA. In 10 healthy knees of whole body cadavers, TKA was performed. Both femoral and tibial components were implanted in different internal (6 degrees) and external (3 and 6 degrees) rotational alignments. Consequential osseous rotational changes between the tibia and the femur were measured in full extension using a commercial computer navigation device. External rotation of the femoral component resulted in significant external rotation of the tibia, while external rotation of the tibial component caused a significant internal rotation of the tibia. The opposite applied to femoral and tibial component internal rotations. Therefore, largest changes of the osseous tibiofemoral rotational postures were found by the combination of 6 degrees femoral component internal and 6 degrees tibial component external rotations (mean 11.2 degrees, standard deviation 5.0, p < 0.001), as both cause tibial internal rotation. In conclusion, the present results suggest that axial component alignment significantly affects lower limb rotational alignment. However, its clinical impact on forefoot progression, Q-angle, the patella, collateral, and cruciate ligaments, and surrounding soft tissues has to be clarified in further clinical and biomechanical studies. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  15. Changes in serum protein profiles of chickens with tibial dyschondroplasia

    USDA-ARS?s Scientific Manuscript database

    Differences in serum protein profiles were analyzed to identify biomarkers associated with a poultry leg problem named tibial dyschondroplasia (TD) that can cause lameness. We used a bead-based affinity matrix containing a combinatorial library of hexapeptides (ProteoMinerTM) to deplete high abundan...

  16. 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...

  17. Biomechanical superiority of plate fixation for proximal tibial osteotomy.

    PubMed

    Hartford, James M; Hester, Peter; Watt, Phil M; Hamilton, Doris; Rohmiller, Michael; Pienkowski, David

    2003-07-01

    Proximal tibial osteotomies require secure and durable fixation to allow early range of motion; however, biomechanical data comparing commonly used fixation methods are lacking. The current study was done to quantify the dynamic biomechanical performance of blade staple fixation and plate fixation of simulated proximal tibial osteotomies. A 15 degrees proximal tibial osteotomy was done on each of 18 synthetic adult composite tibias. Blade staples were used as the means of fixation in nine tibias; plate fixation was used in the remaining nine tibias. The specimens were stressed cyclically in sinusoidal loading whose peak compression and tension loads imitate those measured during normal gait. Device performance was quantified by measuring displacement at the osteotomy site and the number of cycles to failure. Plate fixation had a greater fatigue life than staples (eight plates surviving past 200,000 cycles versus one blade staple) and showed a trend toward less displacement (0.69 mm versus 0.97 mm). Plate fixation of proximal tibial osteotomies offers better fixation and dynamic mechanical performance than blade staples.

  18. Arthroscopically assisted percutaneous osteosynthesis of lateral tibial plateau fractures.

    PubMed

    Kayali, Cemil; Oztürk, Hasan; Altay, Taskin; Reisoglu, Ali; Agus, Haluk

    2008-10-01

    The aim of our study was to evaluate the results of lateral tibial plateau fractures treated with arthroscopically assisted percutaneous osteosynthesis (AAPO). Twenty-one patients (14 men and 7 women) with a mean age of 41 years underwent AAPO to repair low-energy Schatzker I-III tibial plateau fractures. Under pneumatic tourniquet, we reduced and fixed the fracture with 1 or 2 subchondral cannulated screws. Accompanying lesions included 10 meniscus tears, which we partially excised in 9 patients and repaired in 1 patient. On the second postoperative day, patients began range-of-motion exercises. We encouraged partial and full weight-bearing by the sixth and tenth weeks, respectively. The mean follow-up period was 38 (range 12-96) months, and we evaluated the patients using Rasmussen's clinical and radiologic criteria. We used a t test for statistical analysis. There were 13 excellent (62%), 6 good (28%) and 2 fair (10%) clinical results, and 11 excellent (52%), 7 good (33%) and 3 fair (14%) radiologic results. We observed mild or moderate arthritic changes in 5 patients (24%). There were no infection or wound problems, but we removed hardware in 4 patients. Arthroscopically assisted treatment of lateral tibial plateau fractures yields satisfactory results and can be accepted as an alternative and effective method for the treatment of low-energy tibial plateau fractures.

  19. 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

  20. Do ethnicity and gender influence posterior tibial slope?

    PubMed

    Bisicchia, Salvatore; Scordo, Gavinca M; Prins, Johan; Tudisco, Cosimo

    2017-12-01

    Ethnicity and gender can affect posterior tibial slope; however, studies on this topic have limitations and are in disagreement. The aim of the present study was to evaluate posterior tibial slope in a large group of consecutive patients, determining whether ethnicity and gender can influence its value. Secondly, to determine intra- and inter-rater reliability of the two radiographic methods adopted. Posterior tibial slope was calculated (rater 1) in lateral view X-rays of the knee according to the posterior tibial cortex (PTC) and tibial proximal anatomical axis (TPAA) methods. Data were matched with ethnicity and gender. For determination of intra- and inter-rater reliability, 50 random X-rays were selected, and blindly measured by two other raters (2 and 3). A total of 581 radiographs were included (413 white and 168 black knees). Comparing white and black subjects, a statistically significant difference was found for both PTC (4.9 ± 1.2 vs 7.1 ± 2.9, p < 0.0001), and for TPAA (7.7 ± 1.1 vs 10.2 ± 3.0, p < 0.0001). In white subjects, an influence of gender was found only for TPAA (6.4 ± 1.1 in males vs 7.6 ± 1.1 in females, p < 0.0001). In black subjects, an influence of gender was found only for PTC (7.4 ± 3.0 in males vs 6.2 ± 2.9 in females, p = 0.01). Intra-rater reliability was good for both methods for rater 1, and very good for rater 2. Inter-rater reliability among the 3 raters was very good for both methods. Differences in posterior tibial slope between different ethnic groups exist. Differences observed between genders are conflicting and might be too small to have implications in clinical practice. The TPAA method is recommended for the evaluation of posterior tibial slope because of higher intra- and inter-rater reliability. Level of evidence 3 Case-control study.

  1. Posterior Tibial Slope as a Risk Factor for Anterior Cruciate Ligament Rupture in Soccer Players

    PubMed Central

    Şenişik, Seçkin; Özgürbüz, Cengizhan; Ergün, Metin; Yüksel, Oğuz; Taskiran, Emin; Işlegen, Çetin; 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 points Dominant 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. PMID:24149571

  2. Fluoroscopic Analysis of Tibial Translation in Anterior Cruciate Ligament Injured Knees With and Without Bracing During Forward Lunge.

    PubMed

    Jalali, Maryam; Farahmand, Farzam; Mousavi, Seyed Mohammad Ebrahim; Golestanha, Seyed Ali; Rezaeian, Tahmineh; Shirvani Broujeni, Shahram; Rahgozar, Mehdi; Esfandiarpour, Fateme

    2015-07-01

    Despite several studies with different methods, the effect of functional knee braces on knee joint kinematics is not clear. Direct visualization of joint components through medical imaging modalities may provide the clinicians with more useful information. In this study, for the first time in the literature, video fluoroscopy was used to investigate the effect of knee bracing on the sagittal plane kinematics of anterior cruciate ligament (ACL) injured patients. For twelve male unilateral ACL deficient subjects, the anterior tibial translation was measured during lunge exercise in non-braced and braced conditions. Fluoroscopic images were acquired from the subjects using a digital fluoroscopy system with a rate of 10 fps. The image of each frame was scaled using a calibration coin and analyzed in AutoCAD environment. The angle between the two lines, tangent to the posterior cortexes of the femoral and tibial shafts was measured as the flexion angle. For the fluoroscopic images associated with 0°, 15°, 30°, 45° and 60° knee flexion angles, the relative anterior-posterior configuration of the tibiofemoral joint was assessed by measuring the position of landmarks on the tibia and femur. Results indicated that the overall anterior translations of the tibia during the eccentric (down) and concentric (up) phases of lunge exercise were 10.4 ± 1.7 mm and 9.0 ± 2.2 mm for non-braced, and 10.1 ± 3.4 mm and 7.4 ± 2.5 mm, for braced conditions, respectively. The difference of the tibial anterior-posterior translation behaviors of the braced and non-braced knees was not statistically significant. Fluoroscopic imaging provides an effective tool to measure the dynamic behavior of the knee joint in the sagittal plane and within the limitations of this study, the pure mechanical stabilizing effect of functional knee bracing is not sufficient to control the anterior tibial translation of the ACL deficient patients during lunge exercise.

  3. 21 CFR 888.3027 - Polymethylmethacrylate (PMMA) bone cement.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Polymethylmethacrylate (PMMA) bone cement. 888... Polymethylmethacrylate (PMMA) bone cement. (a) Identification. Polymethylmethacrylate (PMMA) bone cement is a device...: Polymethylmethacrylate (PMMA) Bone Cement.” ...

  4. 21 CFR 888.3027 - Polymethylmethacrylate (PMMA) bone cement.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Polymethylmethacrylate (PMMA) bone cement. 888... Polymethylmethacrylate (PMMA) bone cement. (a) Identification. Polymethylmethacrylate (PMMA) bone cement is a device...: Polymethylmethacrylate (PMMA) Bone Cement.” ...

  5. 21 CFR 888.3027 - Polymethylmethacrylate (PMMA) bone cement.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Polymethylmethacrylate (PMMA) bone cement. 888... Polymethylmethacrylate (PMMA) bone cement. (a) Identification. Polymethylmethacrylate (PMMA) bone cement is a device...: Polymethylmethacrylate (PMMA) Bone Cement.” ...

  6. 21 CFR 888.3027 - Polymethylmethacrylate (PMMA) bone cement.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Polymethylmethacrylate (PMMA) bone cement. 888... Polymethylmethacrylate (PMMA) bone cement. (a) Identification. Polymethylmethacrylate (PMMA) bone cement is a device...: Polymethylmethacrylate (PMMA) Bone Cement.” ...

  7. Utilization of municipal sewage sludge as additives for the production of eco-cement.

    PubMed

    Lin, Yiming; Zhou, Shaoqi; Li, Fuzhen; Lin, Yixiao

    2012-04-30

    The effects of using dried sewage sludge as additive on cement property in the process of clinker burning were investigated in this paper. The eco-cement samples were prepared by adding 0.50-15.0% of dried sewage sludge to unit raw meal, and then the mixtures were burned at 1450 °C for 2 h. The results indicated that the major components in the eco-cement clinkers were similar to those in ordinary Portland cement. Although the C(2)S phase formation increased with the increase of sewage sludge content, it was also found that the microstructure of the mixture containing 15.0% sewage sludge in raw meal was significantly different and that a larger amount of pores were distributed in the clinker. Moreover, all the eco-cement pastes had a longer initial setting time and final setting time than those of plain cement paste, which increased as the sewage sludge content in the raw meal increased. All the eco-cement pastes had lower early flexural strengths, which increased as the sewage sludge content increased, while the compressive strengths decreased slightly. However, this had no significant effect on all the strengths at later stages. Furthermore, the leaching concentrations of all the types of eco-cement clinkers met the standard of Chinese current regulatory thresholds. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Factors associated with the loss of thickness of polyethylene tibial bearings after knee arthroplasty.

    PubMed

    Collier, Matthew B; Engh, C Anderson; McAuley, James P; Engh, Gerard A

    2007-06-01

    Wear of the polyethylene tibial bearing is a leading cause of failure of knee replacements done prior to the current decade. The objective of this study was to determine how patient-related factors, implant-related factors, and limb or tibial component alignment influenced the amount of thickness loss in polyethylene tibial bearings that were retrieved at the time of revision surgery or after the death of the patient. We retrieved polyethylene tibial bearings from eighty-one unicondylar and eighty-nine total knee replacements that had been performed because of osteoarthritis with varus deformity from 1984 to 1998. All of the polyethylene bearings had been sterilized with gamma radiation in air. Polyethylene loss was quantified as the change in the minimum bearing thickness per years in vivo (the mean time in vivo [and standard deviation] was 8 +/- 4 years). Multiple linear regression was used to assess whether polyethylene loss was associated with age, weight, gender, varus angle of the tibial component, postoperative hip-knee-ankle angle, initial thickness of the polyethylene, shelf age of the polyethylene, and either the type of polyethylene (for total knee replacements, which were of one posterior cruciate ligament-retaining design) or the manufacturer (for unicondylar knee replacements), and to determine the magnitude by which polyethylene loss would change if any of the significant risk factors were changed. The mean loss (and standard deviation) of polyethylene thickness in the medial compartment of total knee replacements (0.33 +/- 0.28 mm/yr) and that in medial unicompartmental knee replacements (0.49 +/- 0.40 mm/yr) were significantly (p < 0.05) associated with the same three variables: patient age, postoperative hip-knee-ankle angle, and shelf age of the polyethylene. A total knee bearing with a one-year increase in shelf age, a unicondylar knee bearing with a six-month increase in shelf age, a patient who was ten years younger at the time of operation

  9. Posteromedially placed plates with anterior staple reinforcement are not successful in decreasing tibial slope in opening-wedge proximal tibial osteotomy.

    PubMed

    Dean, Chase S; Chahla, Jorge; Matheny, Lauren M; Cram, Tyler R; Moulton, Samuel G; Dornan, Grant J; Mitchell, Justin J; LaPrade, Robert F

    2017-12-01

    To document the effectiveness of a novel technique to decrease tibial slope in patients who underwent a proximal opening-wedge osteotomy with an anteriorly sloped plate placed in a posteromedial position. The hypothesis was that posteromedial placement of an anteriorly sloped osteotomy plate with an adjunctive anterior bone staple on the tibia would decrease, and maintain, the tibial slope correction at a minimum of 6 months following the osteotomy. All patients who underwent biplanar medial opening-wedge proximal tibial osteotomy with anterior staple augmentation to decrease sagittal plane tibial slope were included, and data were collected prospectively and reviewed retrospectively. Indications for decreasing tibial slope included medial compartment osteoarthritis with at least one of the following: ACL deficiency, posterior meniscus deficiency, or flexion contracture. Preoperative, immediate postoperative, and 6-month postoperative radiographs were reviewed. Twenty-one patients (14 males and 7 females) were included in the study with a mean age of 36.5 years. Intrarater and interrater reliability of slope measurements were excellent at all time points (ICC ≥ 0.94, ICC ≥ 0.85). The osteotomy resulted in an average tibial slope decrease of 0.8 from preoperative (n.s.). At 6-month postoperative, average slope was not significantly different from time-zero postoperative slope (mean = +0.2°). The most important finding of this study was that posteromedial placement of an anteriorly angled osteotomy plate augmented with an anterior staple during a biplanar medial opening-wedge proximal tibial osteotomy did not decrease sagittal plane tibial slope. Whether a staple was effective in maintaining tibial slope from time zero to 6 months postoperatively was unable to be assessed due to no significant change in tibial slope from the preoperative postoperative states. The results of this study note that current osteotomy plate designs and surgical techniques are

  10. Long-term follow up of single-stage anterior cruciate ligament reconstruction and high tibial osteotomy and its relation with posterior tibial slope.

    PubMed

    Arun, G R; Kumaraswamy, Vinay; Rajan, David; Vinodh, K; Singh, Ashutosh Kumar; Kumar, Pradeep; Chandrasekaran, Karthik; Santosh, Sahanand; Kishore, Chandan

    2016-04-01

    Open-wedge high tibial osteotomy is considered to be an effective treatment for medial compartmental osteoarthritis. It is generally admitted that tibial slope increases after open-wedge high tibial osteotomy and decreases after closing-wedge high tibial osteotomy. Young patients with anterior cruciate ligament (ACL) deficiency along with medial compartment osteoarthritis need a combined procedure of ACL reconstruction along with high tibial osteotomy to regain physiological knee kinematics and to avoid chondral damage. We retrospectively analysed data from 30 patients who underwent arthroscopic ACL reconstruction along with medial opening-wedge osteotomy from Jan 2004 to June 2012 with a minimum follow up of 2 years. The pre-operative and post-operative posterior tibial slopes were measured. Functional outcome was analysed using clinico-radiological criteria, IKDC scoring and Lysholm score. Post-operative patients improved both clinically and functionally. The patients who had posterior tibial slope >5° decrease, compared to patients who had less <5° decrease, had better functional scores (IKDC and Lysholm score), which was statistically significant (p < 0.05). Our study has shown that decreasing the tibial slope >5° compared to pre-operative value has functionally favourable effect on the reconstructed ACL graft and outcome. It is known that increasing slope causes an anterior shift in tibial resting position that is accentuated under axial loads. This suggests that decreasing tibial slope may be protective in an ACL deficient knee. Hence by placing the tricortical graft posterior to midline in the opening wedge reduces the posterior tibial slope and thereby reduces the stress on the graft leading to better functional outcome.

  11. Rheological Properties of Cemented Tailing Backfill and the Construction of a Prediction Model

    PubMed Central

    Lang, Liu; Song, KI-IL; Lao, Dezheng; Kwon, Tae-Hyuk

    2015-01-01

    Workability is a key performance criterion for mining cemented tailing backfill, which should be defined in terms of rheological parameters such as yield stress and plastic viscosity. Cemented tailing backfill is basically composed of mill tailings, Portland cement, or blended cement with supplementary cement material (fly ash and blast furnace slag) and water, among others, and it is important to characterize relationships between paste components and rheological properties to optimize the workability of cemented tailing backfill. This study proposes a combined model for predicting rheological parameters of cemented tailing backfill based on a principal component analysis (PCA) and a back-propagation (BP) neural network. By analyzing experimental data on mix proportions and rheological parameters of cemented tailing backfill to determine the nonlinear relationships between rheological parameters (i.e., yield stress and viscosity) and mix proportions (i.e., solid concentrations, the tailing/cement ratio, the specific weight, and the slump), the study constructs a prediction model. The advantages of the combined model were as follows: First, through the PCA, original multiple variables were represented by two principal components (PCs), thereby leading to a 50% decrease in input parameters in the BP neural network model, which covered 98.634% of the original data. Second, in comparison to conventional BP neural network models, the proposed model featured a simpler network architecture, a faster training speed, and more satisfactory prediction performance. According to the test results, any error between estimated and expected output values from the combined prediction model based on the PCA and the BP neural network was within 5%, reflecting a remarkable improvement over results for BP neural network models with no PCA.

  12. Heterogeneous Glasses and Sustainable Cement

    NASA Astrophysics Data System (ADS)

    Del Gado, Emanuela

    2015-03-01

    Calcium-silicate hydrate (C-S-H) is the main binding agent in cement and concrete. It forms at the beginning of cement hydration, it progressively densifies as cement hardens and is ultimately responsible for the performances of concrete. This hydration product is a cohesive nano-scale heterogeneous glass, whose structure and mechanics are still poorly understood, in spite of its practical importance. I will review some of the open questions for this fascinating material and discuss a statistical physics approach recently developed, which allows us to investigate the structural arrest and solidification under the out-of-equilibrium conditions typical of cement hydration and the role of the nano-scale structure in C-S-H mechanics upon hardening. Our approach unveils how some distinctive features of the kinetics of cement hydration can be related to changes in the morphology of this glassy material and elucidates the role of nano-scale mechanical heterogeneities in the hardened C-S-H.

  13. Degradable borate glass polyalkenoate cements.

    PubMed

    Shen, L; Coughlan, A; Towler, M; Hall, M

    2014-04-01

    Glass polyalkenoate cements (GPCs) containing aluminum-free borate glasses having the general composition Ag2O-Na2O-CaO-SrO-ZnO-TiO2-B2O3 were evaluated in this work. An initial screening study of sixteen compositions was used to identify regions of glass formation and cement compositions with promising rheological properties. The results of the screening study were used to develop four model borate glass compositions for further study. A second round of rheological experiments was used to identify a preferred GPC formulation for each model glass composition. The model borate glasses containing higher levels of TiO2 (7.5 mol %) tended to have longer working times and shorter setting times. Dissolution behavior of the four model GPC formulations was evaluated by measuring ion release profiles as a function of time. All four GPC formulations showed evidence of incongruent dissolution behavior when considering the relative release profiles of sodium and boron, although the exact dissolution profile of the glass was presumably obscured by the polymeric cement matrix. Compression testing was undertaken to evaluate cement strength over time during immersion in water. The cements containing the borate glass with 7.5 mol % TiO2 had the highest initial compressive strength, ranging between 20 and 30 MPa. No beneficial aging effect was observed-instead, the strength of all four model GPC formulations was found to degrade with time.

  14. Fracture Mechanics Applicability to Portland Cement Concretes,

    DTIC Science & Technology

    The applicability of linear-elastic fracture mechanics to cement paste , mortar, and concrete was determined by the fabrication, testing, and analysis...in cement paste , mortar or concrete. The experimental results were correlated with the model. (Author)

  15. Freezing resistance of high iron phoasphoaluminate cement

    NASA Astrophysics Data System (ADS)

    Zhang, S. X.; Lu, L. C.; Wang, S. D.; Zhao, P. Q.; Gong, C. C.

    2017-03-01

    The influence of freeze-thaw cycle on the mechanical properties of high iron phoasphoaluminate cement was investigated in the present study. The visual examination was conducted to evaluate the surface damage. The deterioration considering the weight loss, modulus loss of relative dynamic elastic and strength loss of mortar were also investigated. The morphology of hydration products were analysed by SEM. Compared with ordinary Portland cement and sulphoaluminate cement, the frost resistance of high iron phosphoraluminate cement is better. Hydration products of high iron phoasphoaluminate cement contain sheet crystals, and a lot of gel form a dense three-dimensional network structure, which results in a lower porosity. Different from ordinary Portland cement, the hydration product of high iron phoasphoaluminate cement does not contain Ca(OH)2, and low alkalinity reduces its osmotic pressure. The lower porosity and osmotic pressure are the two main reasons which causes in the higher frost resistance of high iron phoasphoaluminate cement.

  16. Quantification of tibial bone loss in antegrade versus retrograde tunnel placement for anterior cruciate ligament reconstruction.

    PubMed

    Osti, Michael; Krawinkel, Alessa; Hoffelner, Thomas; Benedetto, Karl Peter

    2015-08-01

    Tibial bone destruction during primary graft tunnel placement and tibial bone loss following tunnel enlargement represent major challenges in revision reconstruction of the anterior cruciate ligament (ACL). Initial all-inside ACL reconstruction facilitates the preparation of tibial bone sockets rather than full tunnels that potentially preserve tibial bone stock. The purpose of this study was to comparatively assess length, diameter and volume of tibial graft tunnels following all-inside and conventional ACL reconstruction. Postoperative computed tomography (CT) scans of 59 patients were assessed following ACL reconstruction. In 35 patients we used conventional antegrade tibial tunnel drilling and in 24 all-inside retrograde tibial bone sockets. Imaging analysis included total, minimal and maximal tunnel length and tunnel diameter. Tunnel volumes were calculated corresponding to these parameters. Statistically significant group differences (p < 0.01) could be detected for tibial tunnel volume, length and diameter between conventional antegrade and all-inside retrograde tibial bone tunnels and sockets, respectively. Compared with conventional techniques, all-inside retrograde drilling of tibial bone sockets is effective in preserving significant bone stock, which might be beneficial for revision reconstruction in cases of eventual primary graft failure.

  17. An Anatomic and Radiographic Study of the Distal Tibial Epiphysis.

    PubMed

    Nguyen, Cynthia V; Greene, Janelle D; Cooperman, Daniel R; Liu, Raymond W

    2017-10-09

    Although the undulating shape of the distal tibial epiphysis is well recognized, its anatomic features have not been well quantified in the literature. To guide the placement of surgical implants about the distal tibial physis, we investigated the topographical anatomy of the distal tibial epiphysis and explored the ability of standard radiographs to visualize the physis. We studied 30 cadaveric distal tibial epiphyses in specimens 3 to 14 years of age. Anteroposterior (AP) and lateral radiographs were obtained of each specimen and then repeated after flexible radiopaque markers were placed on the major undulations. All radiographs were analyzed to determine the height or depth of each landmark, and measurements with and without markers for each landmark were compared using intraclass correlation coefficients (ICC). In 9 specimens, similar measurements were obtained on high-resolution 3-dimensional (3D) surface scans. There were 4 distinct physeal undulations usually present: an anteromedial peak (Kump's bump), a posterolateral peak, an anterior central valley, and a posterior central valley. On the 3D scans, Kump's bump averaged 5.0 mm (range, 3.0 to 6.4 mm), the posterolateral peak 2.4 mm (range, 1.2 to 5.0 mm), the anterior valley 1.3 mm (range, 0 to 3.6 mm), and the posterior valley 0.77 mm (range, 0 to 2.7 mm). Lateral radiographs with markers correlated with measurements from 3D scans better than those without markers (ICC=0.61 vs. 0.24). For AP radiographs, correlation was good to excellent regardless of marker use (ICC=0.76 vs. 0.66). There are 4 major undulations of the distal tibial physis. Kump's bump is the largest. A centrally placed epiphyseal screw in the medial/lateral direction or screws from anterolateral to posteromedial and anteromedial to posterolateral would tend to avoid both valleys. Particular caution should be taken when placing metaphyseal screws in the anteromedial or posterolateral distal tibia. Physeal undulations were

  18. Pressurized cement fixation in total hip arthroplasty.

    PubMed

    Weber, B G

    1988-07-01

    In a follow-up study of 108 total hip arthroplasties, the 92% excellent and good results after seven to 11 years of implantation are evidence in support of cement fixation. The precision of the cementing technique is essential for a high percentage of successful results after ten or more years. Restricted reaming, brushing and lavage to remove debris, use of high-viscosity cement, and pressurization of the cement are of paramount importance.

  19. 76 FR 50252 - Gray Portland Cement and Cement Clinker From Japan; Scheduling of an Expedited Five-Year Review...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-12

    ... COMMISSION Gray Portland Cement and Cement Clinker From Japan; Scheduling of an Expedited Five-Year Review Concerning the Antidumping Duty Order on Gray Portland Cement and Cement Clinker From Japan AGENCY: United... cement and cement clinker from Japan would be likely to lead to continuation or recurrence of material...

  20. 76 FR 24519 - Gray Portland Cement and Cement Clinker From Japan; Institution of a Five-Year Review Concerning...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-02

    ... COMMISSION Gray Portland Cement and Cement Clinker From Japan; Institution of a Five-Year Review Concerning the Antidumping Duty Order on Gray Portland Cement and Cement Clinker From Japan AGENCY: United States... determine whether revocation of the antidumping duty order on gray portland cement and cement clinker from...

  1. Evaluation of two novel aluminum-free, zinc-based glass polyalkenoate cements as alternatives to PMMA bone cement for use in vertebroplasty and balloon kyphoplasty.

    PubMed

    Lewis, Gladius; Towler, Mark R; Boyd, Daniel; German, Matthew J; Wren, Anthony W; Clarkin, Owen M; Yates, Andrew

    2010-01-01

    Vertebroplasty (VP) and balloon kyphoplasty (BKP) are now widely used for treating patients in whom the pain due to vertebral compression fractures is severe and has proved to be refractory to conservative treatment. These procedures involve percutaneous delivery of a bolus of an injectable bone cement either directly to the fractured vertebral body, VB (VP) or to a void created in it by an inflatable bone tamp (BKP). Thus, the cement is a vital component of both procedures. In the vast majority of VPs and BKPs, a poly(methyl methacrylate) (PMMA) bone cement is used. This material has many shortcomings, notably lack of bioactivity and very limited resorbability. Thus, there is room for alternative cements. We report here on two variants of a novel, bioactive, Al-free, Zn-based glass polyalkenoate cement (Zn-GPC), and how their properties compare to those of an injectable PMMA bone cement (SIMPL) that is widely used in VP and BKP. The properties determined were injectability, radiopacity, uniaxial compressive strength, and biaxial flexural modulus. In addition, we compared the compression fatigue lives of a validated synthetic osteoporotic VB model (a polyurethane foam cube with an 8 mm-diameter through-thickness cylindrical hole), at 0-2300 N and 3 Hz, when the hole was filled with each of the three cements. A critical review of the results suggests that the performance of each of the Zn-GPCs is comparable to that of SIMPL; thus, the former cements merit further study with a view to being alternatives to an injectable PMMA cement for use in VP and BKP.

  2. ADVANCED CEMENTS FOR GEOTHERMAL WELLS

    SciTech Connect

    SUGAMA,T.

    2007-01-01

    Using the conventional well cements consisting of the calcium silicate hydrates (CaO-SiO{sub 2}-H{sub 2}O system) and calcium aluminum silicate hydrates (CaO-Al{sub 2}O{sub 3}-SiO{sub 2}-H{sub 2}O system) for the integrity of geothermal wells, the serious concern confronting the cementing industries was their poor performance in mechanically supporting the metallic well casing pipes and in mitigating the pipe's corrosion in very harsh geothermal reservoirs. These difficulties are particularly acute in two geological regions: One is the deep hot downhole area ({approx} 1700 m depth at temperatures of {approx} 320 C) that contains hyper saline water with high concentrations of CO{sub 2} (> 40,000 ppm) in conjunction with {approx} 100 ppm H{sub 2}S at a mild acid of pH {approx} 5.0; the other is the upper well region between the well's surface and {approx} 1000 m depth at temperatures up to 200 C. The specific environment of the latter region is characterized by highly concentrated H{sub 2}SO{sub 4} (pH < 1.5) brine containing at least 5000 ppm CO{sub 2}. When these conventional cements are emplaced in these harsh environments, their major shortcoming is their susceptibility to reactions with hot CO{sub 2} and H{sub 2}SO4, thereby causing their deterioration brought about by CO{sub 2}-catalyzed carbonation and acid-initiated erosion. Such degradation not only reduced rapidly the strength of cements, lowering the mechanical support of casing pipes, but also increased the extent of permeability of the brine through the cement layer, promoting the rate of the pipe's corrosion. Severely carbonated and acid eroded cements often impaired the integrity of a well in less than one year; in the worst cases, casings have collapsed within three months, leading to the need for costly and time-consuming repairs or redrilling operations. These were the reasons why the geothermal well drilling and cementing industries were concerned about using conventional well cements, and further

  3. Development of strength in cements

    NASA Astrophysics Data System (ADS)

    Matkovic, B.

    1981-04-01

    The production of doped belite (dicalcium silicate) clinkers as a prospective means for saving energy in Portland cement production is described. This is accomplished by small additions of either barium sulfate (BaSO4), calcium tribasic phosphate (Ca5(PO4)3OH), or vanadium oxide (V2O5) to belite (Ca2SiO4) clinker. In addition to conserving energy, doping the belite with barium sulfate imparts greater strength to the resulting modified belite. Reactants, additives, and factors contributing to the fabrication of Sorel cement are described.

  4. 21 CFR 872.3275 - Dental cement.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Dental cement. 872.3275 Section 872.3275 Food and... DENTAL DEVICES Prosthetic Devices § 872.3275 Dental cement. (a) Zinc oxide-eugenol—(1) Identification... filling or as a base cement to affix a temporary tooth filling, to affix dental devices such as crowns or...

  5. 21 CFR 872.3275 - Dental cement.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental cement. 872.3275 Section 872.3275 Food and... DENTAL DEVICES Prosthetic Devices § 872.3275 Dental cement. (a) Zinc oxide-eugenol—(1) Identification... filling or as a base cement to affix a temporary tooth filling, to affix dental devices such as crowns or...

  6. 21 CFR 872.3275 - Dental cement.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Dental cement. 872.3275 Section 872.3275 Food and... DENTAL DEVICES Prosthetic Devices § 872.3275 Dental cement. (a) Zinc oxide-eugenol—(1) Identification... filling or as a base cement to affix a temporary tooth filling, to affix dental devices such as crowns or...

  7. 21 CFR 872.3275 - Dental cement.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Dental cement. 872.3275 Section 872.3275 Food and... DENTAL DEVICES Prosthetic Devices § 872.3275 Dental cement. (a) Zinc oxide-eugenol—(1) Identification... filling or as a base cement to affix a temporary tooth filling, to affix dental devices such as crowns or...

  8. 21 CFR 872.3275 - Dental cement.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Dental cement. 872.3275 Section 872.3275 Food and... DENTAL DEVICES Prosthetic Devices § 872.3275 Dental cement. (a) Zinc oxide-eugenol—(1) Identification... filling or as a base cement to affix a temporary tooth filling, to affix dental devices such as crowns or...

  9. Use of foot orthoses and calf stretching for individuals with medial tibial stress syndrome.

    PubMed

    Loudon, Janice K; Dolphino, Martin R

    2010-02-01

    Use of orthotics and calf stretching may alleviate symptoms in runners with medial tibial stress syndrome (MTSS). The objective of this study was to determine which patients with MTSS have a positive response to off-the-shelf foot orthoses and calf stretching based on selected clinical tests to establish a clinical prediction rule. This prospective cohort/predictive validity study enrolled 23 women and men aged 22 to 44 years with symptoms of MTSS. Interventions included off-the-shelf basic foot orthotics and calf stretching. Fifteen of the 23 runners had a 50% reduction of pain in 3 weeks of intervention. Duration was a significant factor that differentiated groups. Although an initial treatment for runners with MTSS may include off-the-shelf orthotics and calf stretching, this regimen should be only one component of an individualized rehabilitation program.

  10. Vibrational study on the bioactivity of Portland cement-based materials for endodontic use

    NASA Astrophysics Data System (ADS)

    Taddei, P.; Tinti, A.; Gandolfi, M. G.; Rossi, P. L.; Prati, C.

    2009-04-01

    The bioactivity of a modified Portland cement (wTC) and a phosphate-doped wTC cement (wTC-P) was studied at 37 °C in Dulbecco's Phosphate Buffered Saline (DPBS). The cements, prepared as disks, were analysed at different ageing times (from 1 day to 2 months) by micro-Raman and ATR/FT-IR spectroscopies. The presence of deposits on the surface of the cements and the composition changes as a function of the storage time were investigated. The presence of an apatite deposit on the surface of both cements was already revealed after one day of ageing in DPBS. The trend of the I 965/I 991 Raman intensity ratio indicated the formation of a meanly thicker apatite deposit on the wTC-P cement at all the investigated times. This result was confirmed by the trend of the I 1030/I 945 IR intensity ratio calculated until 14 days of ageing. At 2 months, the thickness of the apatite deposit on wTC and wTC-P was about 200 and 500 μm, respectively, as estimated by micro-Raman spectroscopy, confirming the higher bioactivity of the phosphate-doped cement. Vibrational techniques allowed to gain more insights into the cement transformation and the different hydration rates of the various cement component. The setting of the cement and the formation of the hydrated silicate gel (C-S-H phase) was spectroscopically monitored through the I 830/I 945 IR intensity ratio.

  11. Coagulated silica - a-SiO2 admixture in cement paste

    NASA Astrophysics Data System (ADS)

    Pokorný, Jaroslav; Pavlíková, Milena; Záleská, Martina; Rovnaníková, Pavla; Pavlík, Zbyšek

    2016-07-01

    Amorphous silica (a-SiO2) in fine-grained form possesses a high pozzolanic activity which makes it a valuable component of blended binders in concrete production. The origin of a-SiO2 applied in cement-based composites is very diverse. SiO2 in amorphous form is present in various amounts in quite a few supplementary cementing materials (SCMs) being used as partial replacement of Portland cement. In this work, the applicability of a commercially produced coagulated silica powder as a partial replacement of Portland cement in cement paste mix design is investigated. Portland cement CEM I 42.5R produced according to the EU standard EN 197-1 is used as a reference binder. Coagulated silica is applied in dosages of 5 and 10 % by mass of cement. The water/binder ratio is kept constant in all the studied pastes. For the applied silica, specific surface area, density, loss on ignition, pozzolanic activity, chemical composition, and SiO2 amorphous phase content are determined. For the developed pastes on the basis of cement-silica blended binder, basic physical properties as bulk density, matrix density, and total open porosity are accessed. Pore size distribution is determined using MIP analysis. Initial and final setting times of fresh mixtures are measured by automatic Vicat apparatus. Effect of silica admixture on mechanical resistivity is evaluated using compressive strength, bending strength, and dynamic Young's modulus measurement. The obtained data gives evidence of a decreased workability of paste mixtures with silica, whereas the setting process is accelerated. On the other hand, reaction activity of silica with Portland cement minerals results in a slight decrease of porosity and improvement of mechanical resistivity of cement pastes containing a-SiO2.

  12. Early-age hydration and volume change of calcium sulfoaluminate cement-based binders

    NASA Astrophysics Data System (ADS)

    Chaunsali, Piyush

    Shrinkage cracking is a predominant deterioration mechanism in structures with high surface-to-volume ratio. One way to allay shrinkage-induced stresses is to use calcium sulfoaluminate (CSA) cement whose early-age expansion in restrained condition induces compressive stress that can be utilized to counter the tensile stresses due to shrinkage. In addition to enhancing the resistance against shrinkage cracking, CSA cement also has lower carbon footprint than that of Portland cement. This dissertation aims at improving the understanding of early-age volume change of CSA cement-based binders. For the first time, interaction between mineral admixtures (Class F fly ash, Class C fly ash, and silica fume) and OPC-CSA binder was studied. Various physico-chemical factors such as the hydration of ye'elimite (main component in CSA cement), amount of ettringite (the main phase responsible for expansion in CSA cement), supersaturation with respect to ettringite in cement pore solution, total pore volume, and material stiffness were monitored to examine early-age expansion characteristics. This research validated the crystallization stress theory by showing the presence of higher supersaturation level of ettringite, and therefore, higher crystallization stress in CSA cement-based binders. Supersaturation with respect to ettringite was found to increase with CSA dosage and external supply of gypsum. Mineral admixtures (MA) altered the expansion characteristics in OPC-CSA-MA binders with fixed CSA cement. This study reports that fly ash (FA) behaves differently depending on its phase composition. The Class C FA-based binder (OPC-CSA-CFA) ceased expanding beyond two days unlike other OPC-CSA-MA binders. Three factors were found to govern expansion of CSA cement-based binders: 1) volume fraction of ettringite in given pore volume, 2) saturation level of ettringite, and 3) dynamic modulus. Various models were utilized to estimate the macroscopic tensile stress in CSA cement

  13. Recent progress in the diagnosis and treatment of posterior tibial plateau fractures

    PubMed Central

    Chen, Hongwei; Chang, Shimin; Pan, Jun

    2015-01-01

    The posterior tibial plateau fracture is drawing increasing attention from orthopedists in recent years with the popularity of CT. However, due to the particular and severity of posterior tibial plateau fracture, there is still controversy in its classification and treatment. It is very difficult to achieve the ideal reduction and fixation by conventional techniques and approaches. The modified posterior approach is favorable for posterior tibial plateau fracture, but disadvantages remain. Recently, the lateral approach is applied by doctors. It is ideal for treatment of posterior tibial plateau fracture. Because of the complexity of local anatomical structure, the operative management of posterior tibial plateau fractures is a contentious issue as revealed in the recent surge of published literature addressing the surgical approach. This review mainly summaries the diagnosis, classification and surgery of the posterior tibial plateau fractures. PMID:26131147

  14. Multiple Tibial Insufficiency Fractures in the Same Tibia

    PubMed Central

    Defoort, Saartje; Mertens, Peter

    2011-01-01

    Stress fractures were first described by Briethaupt in 1855. Since then, there have been many discussions in the literature concerning stress fractures, which have been described in both weight-bearing and non-weight-bearing bones. Currently, the tibia is the most frequent location, but multiple stress fractures in the same tibia are rare. This paper presents an unusual case of a 60-year-old woman with multiple tibial stress fractures of spontaneous onset. PMID:23569673

  15. Evaluation of alveolar grafting with tibial graft in adolescent patients.

    PubMed

    Hussain, Sadique

    2013-01-01

    In a resource-limited setting, use of advanced reconstruction procedures for cleft patient is unaffordable. The autogenous graft sites such as iliac or rib are not favored owing to socio-ethno-economic and cosmetic reasons. In such situations, tibial graft is an excellent alternative. There is limited literature on the use of tibial graft from India and this manuscript attempts to address this lacuna. Archives of a single department on cleft palate cases treated with tibial graft were collected. Cases fulfilling the inclusion and exclusion criteria were selected. The efficiency of treatment was evaluated from the orthopantomogram (OPG) and/or computed tomogram (CT) imaging using previously described methodology. All the data collected were analyzed using Microsoft Excel. The mean age of the patients was 17.78 ± 3.29 years with a range of 13-23 years. Three patients had been treated with secondary bone grafting, while the remainder had been treated with tertiary bone grafting. The median age of the study population was 17.39 years, while the mode was 17 years. The mean efficiency in terms of preoperative and post-operative size of defects as measured in OPG was 74.32 ± 7.31, while it was 73.15 ± 9.9 as measured in CT. All the patients were comfortable with closure of the defect. Patients treated with secondary bone grafting had a mean efficiency was 79.53 ± 9.07, while for tertiary grafting, it was 71.72 ± 4.86. The tibial graft offers an excellent alternative to the conventional standard grafts such as iliac crest or rib grafts. The efficiency of the treatment measured at 6 months period on standard OPG or CT is comparable to the results obtained with the rib/iliac crest.

  16. Treatment of segmental tibial fractures with supercutaneous plating.

    PubMed

    He, Xianfeng; Zhang, Jingwei; Li, Ming; Yu, Yihui; Zhu, Limei

    2014-08-01

    Segmental tibial fractures usually follow a high-energy trauma and are often associated with many complications. The purpose of this report is to describe the authors' results in the treatment of segmental tibial fractures with supercutaneous locking plates used as external fixators. Between January 2009 and March 2012, a total of 20 patients underwent external plating (supercutaneous plating) of the segmental tibial fractures using a less-invasive stabilization system locking plate (Synthes, Paoli, Pennsylvania). Six fractures were closed and 14 were open (6 grade IIIa, 2 grade IIIb, 4 grade II, and 2 grade I, according to the Gustilo classification). When imaging studies confirmed bone union, the plates and screws were removed in the outpatient clinic. Average time of follow-up was 23 months (range, 12-47 months). All fractures achieved union. Median time to union was 19 weeks (range, 12-40 weeks) for the proximal fractures and 22 weeks (range, 12-42 weeks) for the distal fractures. Functional results were excellent in 17 patients and good in 3. Delayed union of the fracture occurred in 2 patients. All patients' radiographs showed normal alignment. No rotational deformities and leg shortening were seen. No incidences of deep infection or implant failures occurred. Minor screw tract infection occurred in 2 patients. A new 1-stage protocol using supercutaneous plating as a definitive fixator for segmental tibial fractures is less invasive, has a lower cost, and has a shorter hospitalization time. Surgeons can achieve good reduction, soft tissue reconstruction, stable fixation, and high union rates using supercutaneous plating. The current patients obtained excellent knee and ankle joint motion and good functional outcomes and had a comfortable clinical course. Copyright 2014, SLACK Incorporated.

  17. Tibial Bowing and Pseudarthrosis in Neurofibromatosis Type 1

    DTIC Science & Technology

    2013-04-01

    Neurofibromatosis Type 1 PRINCIPAL INVESTIGATOR: David A. Stevenson, M.D. CONTRACTING ORGANIZATION: University of Utah... Neurofibromatosis Type 1 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-11- 1 -0250 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) David Stevenson...observed in 5% of children with neurofibromatosis type 1 (NF1), typically identified in infancy. The majority of NF1 individuals with tibial bowing

  18. Polymer-Cement Composites Containing Waste Perlite Powder.

    PubMed

    Łukowski, Paweł

    2016-10-17

    Polymer-cement composites (PCCs) are materials in which the polymer and mineral binder create an interpenetrating network and co-operate, significantly improving the performance of the material. On the other hand, the need for the utilization of waste materials is a demand of sustainable construction. Various mineral powders, such as fly ash or blast-furnace slag, are successfully used for the production of cement and concrete. This paper deals with the use of perlite powder, which is a burdensome waste from the process of thermal expansion of the raw perlite, as a component of PCCs. The results of the testing of the mechanical properties of the composite and some microscopic observations are presented, indicating that there is a possibility to rationally and efficiently utilize waste perlite powder as a component of the PCC. This would lead to creating a new type of building material that successfully meets the requirements of sustainable construction.

  19. Case report: comprehensive management of medial tibial stress syndrome.

    PubMed

    Krenner, Bernard John

    2002-01-01

    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.

  20. Outcome of surgical treatment of medial tibial stress syndrome.

    PubMed

    Yates, Ben; Allen, Mike J; Barnes, Mike R

    2003-10-01

    Medial tibial stress syndrome is a common chronic sports injury characterized by exercise-induced pain along the posteromedial border of the tibia. The reported outcomes of surgical treatment of this condition have varied. Of seventy-eight patients who underwent surgery for medial tibial stress syndrome, forty-six (thirty-one men and fifteen women) returned for follow-up. The outcomes of the surgery were determined by comparing preoperative and postoperative pain levels as indicated on a visual analog pain scale and ascertaining the ability of the athletes to return to presymptom levels of exercise. The mean duration of postoperative follow-up was thirty months (range, six to sixty-three months). Surgery significantly reduced pain levels (p < 0.001) by an average of 72% as indicated on the visual analog pain scale. An excellent result was achieved in 35% of the limbs; a good result, in 34%; a fair result, in 22%; and a poor result, in 9%. Despite the success with regard to pain reduction, for a variety of reasons only nineteen (41%) of the athletes fully returned to their presymptom sports activity. Surgery can significantly reduce the pain associated with medial tibial stress syndrome. Despite this reduction in pain, athletes should be counseled that a full uninhibited return to sports is not always achieved.

  1. The impact of tibial torsion measurements on gait analysis kinematics

    PubMed Central

    Lucareli, Paulo Roberto Garcia; Santos, Nadia Maria; Godoy, Wagner De; Bernal, Milena Moreira Barreto; Paes, Ângela Tavares; Ramalho, Amancio

    2014-01-01

    Objective: To measure and compare tibial torsion values as assessed by goniometry and three-dimensional kinematics. In addition, the impact of each one of these measurements on kinematic and kinetic results for normal gait was determined. Methods: Twenty-three healthy and fully ambulatory patients were assessed, 11 women and 12 men, from 20 to 40 years old. Data were collected at a laboratory for the three-dimensional analysis of movement with 10 cameras and two force plates. Tibial torsion measurements were obtained using goniometry and three-dimensional kinematics based on the Plug-in Gait model. Afterwards, both procedures were compared, and the impact of each result was assessed on the kinematic and kinetic modeling of the knee and ankle. Results: Pearson's linear correlation coefficient (r=0,504) showed a moderate correlation between the three-dimensional kinematics and goniometry, and between the changes in the measurements. Regarding the processed kinematic and kinetic results for every torsion position, no significant differences were noticed among any of the studied variables (p>0.05). Conclusion: Although statistical correlation among tibial torsion angles by goniometry and three-dimensional kinematic were moderate, kinematic and kinetic analysis of the joints did not reveal any significant changes. Level of Evidence I, Diagnostic Studies - Investigating a Diagnostic Test. PMID:25328438

  2. Tibial rotation-plasty for proximal femoral focal deficiency.

    PubMed

    Kritter, A E

    1977-10-01

    The most common treatment for proximal femoral focal deficiency is amputation at the level of the ankle joint and subsequent prosthetic fitting in the manner used for an above-the-knee amputee. Since 1967, five patients with proximal femoral focal deficiency were treated with the Van Nes procedure -- an 180-degree tibial rotation-plasty to convert the ankle joint to a knee joint. Two of the five patients had excellent results -- the tibial rotation-plasty allowed the ankle joint to function as a knee joint with 90 degrees of flexion and placed it at the level of the contralateral anatomical knee. Fusion of the anatomical knee above the tibial rotation-plasty in these two patients provided a stable tibiofemoral lever arm that functioned as the thigh. Two patients had good results -- satisfactory functional and cosmetic improvement. In the remaining patient, who had associated paraxial fibular hemimelia with absence of the fourth and fifth rays of the foot, the result was a failure.

  3. Morphology and correction of distal tibial valgus deformities.

    PubMed

    Jaeger, G H; Marcellin-Little, D J; Ferretti, A

    2007-12-01

    To characterise distal tibial valgus deformities in dogs through physical examination and radiographic evaluation. In a clinical study of 16 client-owned dogs, twelve unilateral and four bilateral distal tibial valgus deformities were evaluated using palpation and radiographs. The origin and amplitude of angulation, rotation and length deficits if present were measured. Radiographically, fibular length and position in relation to the tibia was compared in affected and clinically normal limbs. The dimensions of the fibular physes were also compared between clinically normal and affected limbs. Rottweilers and Shetland sheepdogs were overrepresented. Valgus deformities ranged from 16 degrees to 48 degrees (median, 32 degrees ) in affected and from 0 degrees to 13 degrees (median, 6 degrees ) in contralateral, clinically normal limbs. Fibular length, fibular position relative to the tibia or physeal dimensions were not statistically different between affected and clinically normal limbs. Many distal tibial valgus deformities in dogs are a uniplanar deformity without concurrent craniocaudal or rotational changes or length deficits. A growth cessation in the fibula does not appear to be responsible for the development of the deformity.

  4. Considerations for proper selection of dental cements.

    PubMed

    Simon, James F; Darnell, Laura A

    2012-01-01

    Selecting the proper cement for sufficient bond strength has become progressively complicated as the number of different materials for indirect restorations has increased. The success of any restoration is highly dependent on the proper cement being chosen and used. The function of the cement is not only to seal the restoration on the tooth but also, in some cases, to support the retention of the restoration. This ability to strengthen retention varies by the cement chosen by the clinician; therefore, careful consideration must precede cement selection.

  5. Method of the cementing of material

    SciTech Connect

    Konovalov, Y.G.; Shutov, G.M.; Khanenya, G.P.; Dyatko, E.K.; Buben, K.K.

    1990-10-30

    Invention relates to woodworking industry and concerns method of cementing of materials of foam plastic with duralumin, glued plywood, etc. Known methods of cementing of materials by effect of electromagnetic field of superhigh frequencies are unproductive and do not make it possible to cement parts on the plane. Target of invention - acceleration of process of cementing of planar, including of complex configuration, parts and assemblies from wood, foam plastic, duralumin, glued plywood and other materials. For this material is cemented under the effect of directed electromagnetic field of superhigh frequency in the range 01-50 GHz, the specific power of 0.5-15 W/cm3.

  6. Process for cementing geothermal wells

    DOEpatents

    Eilers, Louis H.

    1985-01-01

    A pumpable slurry of coal-filled furfuryl alcohol, furfural, and/or a low molecular weight mono- or copolymer thereof containing, preferably, a catalytic amount of a soluble acid catalyst is used to cement a casing in a geothermal well.

  7. Microgravity Investigation of Cement Solidification

    NASA Technical Reports Server (NTRS)

    Neves, Juliana; Radlinska, Aleksandra; Scheetz, Barry

    2017-01-01

    Concrete is the most widely used man-made material in the world, second only to water. The large-scale production of cements contributes to approximately 5% anthropogenic CO2 emission. Microgravity research can lead to more durable and hence more cost-effective material.

  8. Fracture behavior of cemented sand

    NASA Astrophysics Data System (ADS)

    Alqasabi, Ahmad Othman

    While fracture mechanics for cementitious materials and composites in the past three decades have developed mainly in concrete applications, it has not yet gained its rightful place in the geotechnical field. There are many examples in the geotechnical literature, especially those related to brittle and stiff soils, where traditional approaches of analysis have proven to be inadequate. While geotechnical problems are inherently complex in nature, using the finite element method (FEM) with fracture mechanics (FM) have been shown to provide powerful analytical tool that could be used to investigate and solve many problems in geomechanics and geotechnical engineering. This thesis addresses the application of FM concepts and theories in analysis of cemented soils. In addition to theoretical aspects, experiments were conducted to evaluate the application of FM to cemented soils. Three point bending beam tests with crack mouth opening displacements (CMOD) conducted on cemented sand samples showed that fracture parameters, such as CMOD, indeed could play an important role in investigation of such soils. Using this unambiguous material parameter, field engineers might have a reliable measure that could prove to be useful in stability assessment of earth structures and soil structure system. By studying size effect on cemented sand, strong relationship was established between critical CMOD and failure, which might be a very useful index and analysis tool in geotechnical engineering practice.

  9. Electrically conductive Portland cement concrete.

    DOT National Transportation Integrated Search

    1986-01-01

    There is a need for an effective, simple-to-install secondary anode system for use in the cathodic protection of reinforced concrete bridge decks. In pursuit of such a system, carbon fibers and carbon black were incorporated in portland cement concre...

  10. Tibial Growth Disturbance Following Distal Femoral Resection and Expandable Endoprosthetic Reconstruction

    PubMed Central

    Arteau, Annie; Lewis, Valerae O.; Moon, Bryan S.; Satcher, Robert L.; Bird, Justin E.; Lin, Patrick P.

    2015-01-01

    Background: In growing children, an expandable endoprosthesis is commonly used after distal femoral resection to compensate for loss of the distal femoral physis. Our hypothesis was that such prostheses can affect proximal tibial growth, which would contribute to an overall leg-length discrepancy and cause angular deformity. Methods: Twenty-three skeletally immature patients underwent the placement of a distal femoral expandable endoprosthesis between 1994 and 2012. Tibial length, femoral length, and mechanical axis were measured radiographically to determine the growth rate. Results: No patient had radiographic evidence of injury to the proximal tibial physis at the time of surgery other than insertion of the tibial stem. Fifteen (65%) of the patients experienced less proximal tibial growth in the operative compared with the contralateral limb. In ten (43%) of the patients, the discrepancy progressively worsened, whereas in five (22%) of the patients, the discrepancy stabilized. Seven patients did not develop tibial length discrepancy, and one patient had overgrowth of the tibia. For the ten patients with progressive shortening, the proximal tibial physis grew an average of 4.0 mm less per year in the operative limb. Five (22%) of the patients had ≥20 mm of tibial length discrepancy at last follow-up. Three of these patients underwent contralateral tibial epiphysiodesis. Three patients required corrective surgery for angular deformity. Conclusions: The tibial growth plate may not resume normal growth after implantation of a distal femoral prosthesis. Physeal bar resection, prosthesis revision, and contralateral tibial epiphysiodesis may be needed to address tibial growth abnormalities. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence. PMID:26582624

  11. 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.

  12. To Compare and Evaluate the Sorption and Solubility of Four Luting Cements after Immersion in Artificial Saliva of Different pH Values.

    PubMed

    Bharali, Kadambari; Das, Manjula; Jalan, Silpi; Paul, Rajdeep; Deka, Adrija

    2017-11-01

    The word 'luting' is derived from a latin word 'Lutum' which means 'mud'. 'Luting' is a word that is often used to describe the use of a mouldable substance to seal a space or to cement two components together. Therefore in view of the clinical importance of dissolution of luting cements in the oral environment, an in vitro study was designed to compare the sorption and solubility of commercially available luting cements mainly zinc phosphate, Glass Ionomer cement, Resin Modified Glass Ionomer Cement and Resin Cement after immersion in artificial saliva of different ph values of 5 and 7. To Compare and Evaluate the sorption and solubility of four luting cements after immersion in artificial saliva of different pH values. A total of 120 test samples were prepared of which 30 samples of each luting cement were prepared for the purpose of assessing the water solubility and sorptionThese luting cements were grouped as: GROUP- A (Zinc Phosphate cement), GROUP- B (Glass Ionomer Cement), GROUP-C (Resin Modified Cement), GROUP- D (Resin Cement) In these groups, based on immersion of artificial saliva of acidic pH 5 and neutral pH7, the luting cement specimens were subdivided into 2 groups of 15 samples each. The volume (V) of each specimen was calculated using mathematical formula. Resin cement had the highest resistance to solubility and sorption followed by resin modified GIC, Conventional GIC, and Zinc Phosphate which exhibited the least resistance to solubility in both artificial saliva of pH 5 and pH 7.

  13. Traction test of temporary dental cements

    PubMed Central

    Millan-Martínez, Diego; Fons-Font, Antonio; Agustín-Panadero, Rubén; Fernández-Estevan, Lucía

    2017-01-01

    Background Classic self-curing temporary cements obstruct the translucence of provisional restorations. New dual-cure esthetic temporary cements need investigation and comparison with classic cements to ensure that they are equally retentive and provide adequate translucence. The objective is to analyze by means of traction testing in a in vitro study the retention of five temporary cements. Material and Methods Ten molars were prepared and ten provisional resin restorations were fabricated using CAD-CAM technology (n=10). Five temporary cements were selected: self-curing temporary cements, Dycal (D), Temp Bond (TB), Temp Bond Non Eugenol (TBNE); dual-curing esthetic cements Temp Bond Clear (TBC) and Telio CS link (TE). Each sample underwent traction testing, both with thermocycling (190 cycles at 5-55º) and without thermocycling. Results TE and TBC obtained the highest traction resistance values. Thermocycling reduced the resistance of all cements except TBC. Conclusions The dual-cure esthetic cements tested provided optimum outcomes for bonding provisional restorations. Key words:Temporary dental cements, cements resistance. PMID:28469824

  14. Traction test of temporary dental cements.

    PubMed

    Román-Rodríguez, Juan-Luis; Millan-Martínez, Diego; Fons-Font, Antonio; Agustín-Panadero, Rubén; Fernández-Estevan, Lucía

    2017-04-01

    Classic self-curing temporary cements obstruct the translucence of provisional restorations. New dual-cure esthetic temporary cements need investigation and comparison with classic cements to ensure that they are equally retentive and provide adequate translucence. The objective is to analyze by means of traction testing in a in vitro study the retention of five temporary cements. Ten molars were prepared and ten provisional resin restorations were fabricated using CAD-CAM technology (n=10). Five temporary cements were selected: self-curing temporary cements, Dycal (D), Temp Bond (TB), Temp Bond Non Eugenol (TBNE); dual-curing esthetic cements Temp Bond Clear (TBC) and Telio CS link (TE). Each sample underwent traction testing, both with thermocycling (190 cycles at 5-55º) and without thermocycling. TE and TBC obtained the highest traction resistance values. Thermocycling reduced the resistance of all cements except TBC. The dual-cure esthetic cements tested provided optimum outcomes for bonding provisional restorations. Key words: Temporary dental cements, cements resistance.

  15. Lightweight Cement Slurries based on vermiculite

    NASA Astrophysics Data System (ADS)

    Minaev, K.; Gorbenko, V.; Ulyanova, O.

    2014-08-01

    The main purpose of the research is to study the lightweight cement slurry based on vermiculite and its parameters in accordance with GOST 1581-96 requirements as well as improvement of its formulation by polymer additives. Analysis of vermiculite-containing mixture providing the lowest density while maintaining other required parameters was conducted. As a cement base, cement PTscT-I-G-CC-1, cement PTscT - 100 and vermiculite M200 and M150 were used. Vermiculite content varied from 10 to 15 %; and water-to-cement-ratio ranged from 0.65 to 0.8. To sum up, despite the fact that lightweight cement slurry based on vermiculite satisfies GOST 1581-96 requirements under laboratory conditions, field studies are necessary in order to make a conclusion about applicability of this slurry for well cementing.

  16. Radiographic Analysis of Implant Restorative Cement Used in Army Dentistry

    DTIC Science & Technology

    2015-06-01

    cements were made in 0.5 ± 0.01 and 1.0 ± 0.01mm thickness using orthodontic rubber band and glass slabs for each of the five cements. Two different...excess cement extruded upon delivery of implant crowns using four suggested cementation techniques14. They were application of cement on internal...taken. Depending on the film thickness and the viscosity of the cements greater amount of excess cements were extruded [Photo II]. [Photo II

  17. Analysis of Knee Joint Line Obliquity after High Tibial Osteotomy.

    PubMed

    Oh, Kwang-Jun; Ko, Young Bong; Bae, Ji Hoon; Yoon, Suk Tae; Kim, Jae Gyoon

    2016-11-01

    The aim of this study was to evaluate which lower extremity alignment (knee and ankle joint) parameters affect knee joint line obliquity (KJLO) in the coronal plane after open wedge high tibial osteotomy (OWHTO). Overall, 69 knees of patients that underwent OWHTO were evaluated using radiographs obtained preoperatively and from 6 weeks to 3 months postoperatively. We measured multiple parameters of knee and ankle joint alignment (hip-knee-ankle angle [HKA], joint line height [JLH], posterior tibial slope [PS], femoral condyle-tibial plateau angle [FCTP], medial proximal tibial angle [MPTA], mechanical lateral distal femoral angle [mLDFA], KJLO, talar tilt angle [TTA], ankle joint obliquity [AJO], and the lateral distal tibial ground surface angle [LDTGA]; preoperative [-pre], postoperative [-post], and the difference between -pre and -post values [-Δ]). We categorized patients into two groups according to the KJLO-post value (the normal group [within ± 4 degrees, 56 knees] and the abnormal group [greater than ± 4 degrees, 13 knees]), and compared their -pre parameters. Multiple logistic regression analysis was used to examine the contribution of the -pre parameters to abnormal KJLO-post. The mean HKA-Δ (-9.4 ± 4.7 degrees) was larger than the mean KJLO-Δ (-2.1 ± 3.2 degrees). The knee joint alignment parameters (the HKA-pre, FCTP-pre) differed significantly between the two groups ( p  < 0.05). In addition, the HKA-pre (odds ratio [OR] = 1.27, p  = 0.006) and FCTP-pre (OR = 2.13, p  = 0.006) were significant predictors of abnormal KJLO-post. However, -pre ankle joint parameters (TTA, AJO, and LDTGA) did not differ significantly between the two groups and were not significantly associated with the abnormal KJLO-post. The -pre knee joint alignment and knee joint convergence angle evaluated by HKA-pre and FCTP-pre angle, respectively, were significant predictors of abnormal KJLO after OWHTO. However, -pre ankle joint

  18. Influence of Cellulosic Fibres on the Physical Properties of Fibre Cement Composites

    NASA Astrophysics Data System (ADS)

    Hospodarova, V.; Stevulova, N.; Vaclavik, V.; Dvorsky, T.

    2017-10-01

    Nowadays, there are new approaches directing to processing of non-conventional fibre-cement composites for application in the housing construction. Vegetable cellulosic fibres coming from natural resources used as reinforcement in cost-effective and environmental friendly building products are in the spotlight. The applying of natural fibres in cement based composites is narrowly linked to the ecological building sector, where a choice of materials is based on components including recyclable, renewable raw materials and low-resource manufacture techniques. In this paper, two types of cellulosic fibres coming from wood pulp and recycled waste paper with 0.2%; 0.3% and 0.5% of fibre addition into cement mixtures were used. Differences in the physical characteristics (flowability, density, coefficient of thermal conductivity and water absorbability) of 28 days hardened fibre-cement composites are investigated. Addition of cellulosic fibres to cement mixture caused worsening the workability of fresh mixture as well as absorbability of hardened composites due to hydrophilic nature of biomaterial, whereas density and thermal conductivity of manufactured cement based fibre plaster are enhanced. The physical properties of cement plasters based on cellulosic fibres depend on structural, physical characteristics of cellulosic fibres, their nature and processing.

  19. Long-term complications following tibial plateau levelling osteotomy in small dogs with tibial plateau angles >30°.

    PubMed

    Knight, Rebekah; Danielski, Alan

    2018-01-26

    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.

  20. The effect of cement creep and cement fatigue damage on the micromechanics of the cement-bone interface

    PubMed Central

    Waanders, Daan; Janssen, Dennis; Mann, Kenneth A.; Verdonschot, Nico

    2010-01-01

    The cement-bone interface provides fixation for the cement mantle within the bone. The cement-bone interface is affected by fatigue loading in terms of fatigue damage, or micro cracks, and creep, both mostly in the cement. This study investigates how fatigue damage and cement creep separately affect the mechanical response of the cement-bone interface at various load levels in terms of plastic displacement and crack formation. Two FEA models were created, which were based on micro-computed tomography data of two physical cement-bone interface specimens. These models were subjected to tensile fatigue loads with four different magnitudes. Three deformation modes of the cement were considered; ‘only creep’, ‘only damage’ or ‘creep and damage’. The interfacial plastic deformation, the crack reduction as a result of creep and the interfacial stresses in the bone were monitored. The results demonstrate that, although some models failed early, the majority of plastic displacement was caused by fatigue damage, rather than cement creep. However, cement creep does decrease the crack formation in the cement up to 20%. Finally, while cement creep hardly influences the stress levels in the bone, fatigue damage of the cement considerably increases the stress levels in the bone. We conclude that at low load levels the plastic displacement is mainly caused by creep. At moderate to high load levels, however, the plastic displacement is dominated by fatigue damage and is hardly affected by creep, although creep reduced the number of cracks in moderate to high load region. PMID:20692663

  1. Effect of Osteotomy Position and Tibial Plateau Rotation on the Tensile Force Required for Failure of the Canine Quadriceps Mechanism.

    PubMed

    Hamilton, Katie; Tarlton, John; Parsons, Kevin; Toscano, Mike; Burton, Neil

    2015-08-01

    To measure the tensile force required for failure of the quadriceps mechanism with different tibial tuberosity widths and different degrees of rotation of the tibial plateau after radial osteotomy of the proximal tibia. Ex vivo study, randomized unblocked design Thirty-five hind limbs from 18 adult Greyhound cadavers. Part 1 (15 limbs)--The center of rotation of the proximal tibial radial osteotomy was advanced craniodistally, progressively reducing absolute tibial tuberosity width (ATTW) for 5 different widths. Part 2 (21 limbs)-Tibial plateau rotation was performed at a set ATTW. Rotation was varied as a function of tibial tuberosity position with rotation proximal, level with, or distal to the tuberosity. All 35 limbs were tested with force applied via the quadriceps mechanism until construct failure occurred. All but 2 limbs failed by fracture of the tibial tuberosity. The tensile force required for failure of the quadriceps mechanism increased linearly with increasing ATTW. Significantly less force (P = .016) was required for failure of the quadriceps mechanism when the rotation of the tibial plateau was distal to the level of the patella tendon (mean 1,877 N) compared to when it was above the level of the patella tendon (mean 2,533 N). Rotation of the tibial plateau distal to the level of the patella tendon insertion point resulted in fracture at the base of the tibial tuberosity, level with the tibial plateau buttress. The overwhelming mode of failure of the quadriceps mechanism was by tibial tuberosity fracture, thus this was the weakest part of the construct. Reducing the tibial tuberosity width and rotation of the tibial plateau segment below the patella tendon insertion decreased the force required for tibial tuberosity fracture. These results support the idea of a safe point with the tibial plateau segment providing buttress to the tibial tuberosity. © Copyright 2015 by The American College of Veterinary Surgeons.

  2. A bioactive dental luting cement--its retentive properties and 3-year clinical findings.

    PubMed

    Jefferies, Steven R; Pameijer, Cornelis H; Appleby, David C; Boston, Daniel; Lööf, Jesper

    2013-02-01

    A clinical validation study was conducted to determine the performance of a new bioactive dental cement (Ceramir C&B, Doxa Dental AB) for permanent cementation. The cement is a new formulation class, which is a hybrid material comprised of calcium aluminate and glass-ionomer components. A total of 38 crowns and bridges were cemented in 17 patients; 31 of the abutment teeth were vital and seven were non-vital. Six restorations were bridges with a total of 14 abutment teeth (12 vital/ two non-vital). One fixed splint comprising two abutment teeth was also included. Preparation parameters were recorded, as well as cement characteristics such as working time, setting time, seating characteristics, and ease of cement removal. Baseline data were recorded for the handling of the cement, gingival inflammation, and pre-cementation sensitivity. Post-cementation parameters included post-cementation sensitivity, gingival tissue reaction, marginal integrity, and discoloration. All patients were seen for recall examinations at 30 days and 6 months. Fifteen of 17 subjects and 13 of 17 patients were also available for subsequent comprehensive 1- and 2-year recall examination, and 13 patients were available for a 3-year recall examination. Restorations available for the 3-year recall examination included 14 single-unit full-coverage crown restorations, four three-unit bridges comprising eight abutments, and one two-unit splint. Three-year recall data yielded no loss of retention, no secondary caries, no marginal discolorations, and no subjective sensitivity. All restorations rated excellent for marginal integrity. Average visual analogue scale (VAS) score for tooth sensitivity decreased from 7.63 mm at baseline to 0.44 mm at 6-month recall, 0.20 mm at 1-year recall, and 0.00 mm at 2- and 3-year recall. Average gingival index (GI) score for gingival inflammation decreased from 0.56 at baseline to 0.11 at 6-month recall, 0.16 at 1-year recall, 0.21 at 2-year recall, and 0.07 at 3

  3. The microstructure and surface morphology of radiopaque tricalcium silicate cement exposed to different curing conditions.

    PubMed

    Formosa, L M; Mallia, B; Bull, T; Camilleri, J

    2012-05-01

    Tricalcium silicate is the major constituent phase in mineral trioxide aggregate (MTA). It is thus postulated that pure tricalcium silicate can replace the Portland cement component of MTA. The aim of this research was to evaluate the microstructure and surface characteristics of radiopaque tricalcium silicate cement exposed to different curing conditions namely at 100% humidity or immersed in either water or a simulated body fluid at 37°C. The materials under study included tricalcium silicate and Portland cements with and without the addition of bismuth oxide radiopacifier. Material characterization was performed on hydrated cements using a combination of scanning electron microscopy (SEM) with X-ray energy dispersive (EDX) analyses and X-ray diffraction (XRD) analyses. Surface morphology was further investigated using optical profilometry. Testing was performed on cements cured at 100% humidity or immersed in either water or Hank's balanced salt solution (HBSS) for 1 and 28 days at 37°C. In addition leachate analysis was performed by X-ray fluorescence of the storage solution. The pH of the storage solution was assessed. All the cements produced calcium silicate hydrate and calcium hydroxide on hydration. Tricalcium silicate showed a higher reaction rate than Portland cement and addition of bismuth oxide seemed to also increase the rate of reaction with more calcium silicate hydrate and calcium hydroxide being produced as demonstrated by SEM and XRD analysis and also by surface deposits viewed by the optical profilometer. Cement immersion in HBSS resulted in the deposition of calcium phosphate during the early stages following immersion and extensive calcification after 28 days. The pH of all storage solutions was alkaline. The immersion in distilled water resulted in a higher pH of the solution than when the cements were immersed in HBSS. Leachate analysis demonstrated high calcium levels in all cements tested with higher levels in tricalcium silicate and

  4. Synthesis of Portland cement and calcium sulfoaluminate-belite cement for sustainable development and performance

    NASA Astrophysics Data System (ADS)

    Chen, Irvin Allen

    Portland cement concrete, the most widely used manufactured material in the world, is made primarily from water, mineral aggregates, and portland cement. The production of portland cement is energy intensive, accounting for 2% of primary energy consumption and 5% of industrial energy consumption globally. Moreover, portland cement manufacturing contributes significantly to greenhouse gases and accounts for 5% of the global CO2 emissions resulting from human activity. The primary objective of this research was to explore methods of reducing the environmental impact of cement production while maintaining or improving current performance standards. Two approaches were taken, (1) incorporation of waste materials in portland cement synthesis, and (2) optimization of an alternative environmental friendly binder, calcium sulfoaluminate-belite cement. These approaches can lead to less energy consumption, less emission of CO2, and more reuse of industrial waste materials for cement manufacturing. In the portland cement part of the research, portland cement clinkers conforming to the compositional specifications in ASTM C 150 for Type I cement were successfully synthesized from reagent-grade chemicals with 0% to 40% fly ash and 0% to 60% slag incorporation (with 10% intervals), 72.5% limestone with 27.5% fly ash, and 65% limestone with 35% slag. The synthesized portland cements had similar early-age hydration behavior to commercial portland cement. However, waste materials significantly affected cement phase formation. The C3S--C2S ratio decreased with increasing amounts of waste materials incorporated. These differences could have implications on proportioning of raw materials for cement production when using waste materials. In the calcium sulfoaluminate-belite cement part of the research, three calcium sulfoaluminate-belite cement clinkers with a range of phase compositions were successfully synthesized from reagent-grade chemicals. The synthesized calcium sulfoaluminate

  5. THE TIBIAL APERTURE SURFACE ANALYSIS IN ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION PROCESS.

    PubMed

    Milojević, Zoran; Tabaković, Slobodan; Vićević, Marija; Obradović, Mirko; Vranjes, Miodrag; Milankov, Miroslav Z

    2016-01-01

    The tibial tunnel aperture in the anterior cruciate ligament reconstruction is usually analyzed as an ellipse, generated as an intersection between a tibial plateau and a tibial bone tunnel. The aim of this study is to show that the tibial tunnel aperture, which utilizes 3D tibial surface bone model, differs significantly from common computations which present the tibial tunnel anterior cruciate ligament aperture surface as an ellipse. An interactive program system was developed for the tibial tunnel aperture analysis which included the real tibia 3D surface bone model generated from a series of computed tomography images of ten male patients, their mean age being 25 years. In aperture calculation, the transverse drill angle of 10 degrees was used, whereas sagittal drill angles of 40 degrees, 50 degrees and 60 degrees were used with the drill-bit diameter set to 10 mm. The real 3D and 2D tibial tunnel aperture surface projection was calculated and compared with an ellipse. According to the calculations, generated 3D aperture surfaces were different for every patient even though the same drill parameters were used. For the sagittal drill angles of 40 degrees, 50 degrees and 60 degrees, the mean difference between the projected 3D and 2D area on the tibial plateau was 19.6 +/- 5.4%, 21.1 +/- 8.0% and 21.3 +/- 9.6%, respectively. The difference between the projected 3D area on the tibial plateau and ellipse surface was 54.8 +/- 16.3%, 39.6 +/- 10.4% and 25.0 +/- 8.0% for sagittal drill angles of 40 degrees, 50 degrees and 60 degrees, respectively. The tibial tunnel aperture surface area differs significantly from the ellipse surface area, which is commonly used in the anterior cruciate ligament reconstruction analysis. Inclusion of the 3D shape of the tibial attachment site in the preoperative anterior cruciate ligament reconstruction planning process can lead to a more precise individual anatomic anterior cruciate ligament reconstruction on the tibial bone. Both

  6. Clinical, surface damage and oxidative performance of poly II tibial inserts after long-term implantation.

    PubMed

    Medel, Francisco; Kurtz, Steven M; Klein, Gregg; Levine, Harlan; Sharkey, Peter; Austin, Matthew; Kraay, Matthew; Rimnac, Clare M

    2008-01-01

    Carbon fiber-reinforced ultra-high molecular weight polyethylene (Poly II) was clinically introduced in the 1970s, but catastrophic short-term outcomes were reported in case studies. Clinical use of Poly II persisted into the 1980s until it was eventually abandoned. To date, no studies have documented its long-term clinical and material performance. Forty Poly II tibial inserts of the Total Condylar, Insall-Burstein I, and Miller-Galante I designs were retrieved at revision surgery. Twenty-six historical unreinforced polyethylene knee retrievals of similar designs (Miller-Galante I and II, and Insall-Burstein II) served as the control group. The average in vivo durations of both retrieval groups were similar (11.1 and 11.6 years, respectively), although Poly II had a wider implantation range (3.7-32.8 years) than historical polyethylene (4.4-17.0 years). Surface damage on all the retrievals, as well as oxidation and mechanical strength when possible, were characterized. Poly II tibial inserts had long-term clinical survivability and material performance comparable to unreinforced polyethylene bearings. Poly II retrievals exhibited less surface damage at all the regions than historical components, and they were less sensitive to pitting and delamination, but more susceptible to abrasion and embedded debris. Both Poly II and historical retrievals were found to oxidize in vivo and exhibited similar mechanical strength. This study provides improved understanding of well-consolidated Poly II long-term retrievals and also motivation to revisit carbon fiber-reinforced polymeric bearings for joint replacement in the twenty-first century.

  7. Leaching of heavy metals from cementitious composites made of new ternary cements

    NASA Astrophysics Data System (ADS)

    Kuterasińska-Warwas, Justyna; Król, Anna

    2017-10-01

    The paper presents a comparison of research methods concerning the leaching of harmful substances (selected heavy metal cations ie. Pb, Cu, Zn and Cr) and their degree of immobilization in cement matrices. The new types of ternary cements were used in the study, where a large proportion of cement clinker was replaced by other non-clinker components - industrial wastes, ie. siliceous fly ash from power industry and granulated blast furnace slag from the iron and steel industry. In studied cementitious binders also ground limestone was used, which is a widely available raw material. The aim of research is determining the suitability of new cements for neutralizing harmful substances in the obtained matrices. The application of two research methods in accordance with EN 12457-4 and NEN 7275 intends to reflection of changing environmental conditions whom composite materials may actually undergo during their exploitation or storing on landfills. The results show that cements with high addition of non-clinker components are suitable for stabilization of toxic substances and the obtained cement matrices retain a high degree of immobilization of heavy metals at the level of 99%.

  8. Measurement of transient and residual stresses during polymerization of bone cement for cemented hip implants.

    PubMed

    Nuño, N; Madrala, A; Plamondon, D

    2008-08-28

    The initial fixation of a cemented hip implant relies on the strength of the interface between the stem, bone cement and adjacent bone. Bone cement is used as grouting material to fix the prosthesis to the bone. The curing process of bone cement is an exothermic reaction where bone cement undergoes volumetric changes that will generate transient stresses resulting in residual stresses once polymerization is completed. However, the precise magnitude of these stresses is still not well documented in the literature. The objective of this study is to develop an experiment for the direct measurement of the transient and residual radial stresses at the stem-cement interface generated during cement polymerization. The idealized femoral-cemented implant consists of a stem placed inside a hollow cylindrical bone filled with bone cement. A sub-miniature load cell is inserted inside the stem to make a direct measurement of the radial compressive forces at the stem-cement interface, which are then converted to radial stresses. A thermocouple measures the temperature evolution during the polymerization process. The results show the evolution of stress generation corresponding to volumetric changes in the cement. The effect of initial temperature of the stem and bone as well as the cement-bone interface condition (adhesion or no adhesion) on residual radial stresses is investigated. A maximum peak temperature of 70 degrees C corresponds to a peak in transient stress during cement curing. Maximum radial residual stresses of 0.6 MPa in compression are measured for the preheated stem.

  9. Modified tricalcium silicate cement formulations with added zirconium oxide.

    PubMed

    Li, Xin; Yoshihara, Kumiko; De Munck, Jan; Cokic, Stevan; Pongprueksa, Pong; Putzeys, Eveline; Pedano, Mariano; Chen, Zhi; Van Landuyt, Kirsten; Van Meerbeek, Bart

    2017-04-01

    This study aims to investigate the effect of modifying tricalcium silicate (TCS) cements on three key properties by adding ZrO 2 . TCS powders were prepared by adding ZrO 2 at six different concentrations. The powders were mixed with 1 M CaCl 2 solution at a 3:1 weight ratio. Biodentine (contains 5 wt.% ZrO 2 ) served as control. To evaluate the potential effect on mechanical properties, the mini-fracture toughness (mini-FT) was measured. Regarding bioactivity, Ca release was assessed using ICP-AES. The component distribution within the cement matrix was evaluated by Feg-SEM/EPMA. Cytotoxicity was assessed using an XTT assay. Adding ZrO 2 to TCS did not alter the mini-FT (p = 0.52), which remained in range of that of Biodentine (p = 0.31). Ca release from TSC cements was slightly lower than that from Biodentine at 1 day (p > 0.05). After 1 week, Ca release from TCS 30 and TCS 50 increased to a level that was significantly higher than that from Biodentine (p < 0.05). After 1 month, Ca release all decreased (p < 0.05), yet TCS 0 and TCS 50 released comparable amounts of Ca as at 1 day (p > 0.05). EPMA revealed a more even distribution of ZrO 2 within the TCS cements. Particles with an un-reacted core were surrounded by a hydration zone. The 24-, 48-, and 72-h extracts of TCS 50 were the least cytotoxic. ZrO 2 can be added to TCS without affecting the mini-FT; Ca release was reduced initially, to reach a prolonged release thereafter; adding ZrO 2 made TCS cements more biocompatible. TCS 50 is a promising cement formulation to serve as a biocompatible hydraulic calcium silicate cement.

  10. Ultrasound elasticity imaging of human posterior tibial tendon

    NASA Astrophysics Data System (ADS)

    Gao, Liang

    Posterior tibial tendon dysfunction (PTTD) is a common degenerative condition leading to a severe impairment of gait. There is currently no effective method to determine whether a patient with advanced PTTD would benefit from several months of bracing and physical therapy or ultimately require surgery. Tendon degeneration is closely associated with irreversible degradation of its collagen structure, leading to changes to its mechanical properties. If these properties could be monitored in vivo, it could be used to quantify the severity of tendonosis and help determine the appropriate treatment. Ultrasound elasticity imaging (UEI) is a real-time, noninvasive technique to objectively measure mechanical properties in soft tissue. It consists of acquiring a sequence of ultrasound frames and applying speckle tracking to estimate displacement and strain at each pixel. The goals of my dissertation were to 1) use acoustic simulations to investigate the performance of UEI during tendon deformation with different geometries; 2) develop and validate UEI as a potentially noninvasive technique for quantifying tendon mechanical properties in human cadaver experiments; 3) design a platform for UEI to measure mechanical properties of the PTT in vivo and determine whether there are detectable and quantifiable differences between healthy and diseased tendons. First, ultrasound simulations of tendon deformation were performed using an acoustic modeling program. The effects of different tendon geometries (cylinder and curved cylinder) on the performance of UEI were investigated. Modeling results indicated that UEI accurately estimated the strain in the cylinder geometry, but underestimated in the curved cylinder. The simulation also predicted that the out-of-the-plane motion of the PTT would cause a non-uniform strain pattern within incompressible homogeneous isotropic material. However, to average within a small region of interest determined by principal component analysis (PCA

  11. Lunar cement and lunar concrete

    NASA Astrophysics Data System (ADS)

    Lin, T. D.

    Results of a study to investigate methods of producing cements from lunar materials are presented. A chemical process and a differential volatilization process to enrich lime content in selected lunar materials were identified. One new cement made from lime and anorthite developed compressive strengths of 39 Mpa (5500 psi) for 1 inch paste cubes. The second, a hypothetical composition based on differential volatilization of basalt, formed a mineral glass which was activated with an alkaline additive. The 1 inch paste cubes, cured at 100C and 100 percent humidity, developed compressive strengths in excess of 49 Mpa (7100 psi). Also discussed are tests made with Apollo 16 lunar soil and an ongoing investigation of a proposed dry mix/steam injection procedure for casting concrete on the Moon.

  12. Lunar cement and lunar concrete

    NASA Technical Reports Server (NTRS)

    Lin, T. D.

    1991-01-01

    Results of a study to investigate methods of producing cements from lunar materials are presented. A chemical process and a differential volatilization process to enrich lime content in selected lunar materials were identified. One new cement made from lime and anorthite developed compressive strengths of 39 Mpa (5500 psi) for 1 inch paste cubes. The second, a hypothetical composition based on differential volatilization of basalt, formed a mineral glass which was activated with an alkaline additive. The 1 inch paste cubes, cured at 100C and 100 percent humidity, developed compressive strengths in excess of 49 Mpa (7100 psi). Also discussed are tests made with Apollo 16 lunar soil and an ongoing investigation of a proposed dry mix/steam injection procedure for casting concrete on the Moon.

  13. Medium-term outcomes following limb salvage for severe open tibia fracture are similar to trans-tibial amputation.

    PubMed

    Penn-Barwell, J G; Myatt, R W; Bennett, P M; Sargeant, I D

    2015-02-01

    Extremity injuries define the surgical burden of recent conflicts. Current literature is inconclusive when assessing the merits of limb salvage over amputation. The aim of this study was to determine medium term functional outcomes in military casualties undergoing limb salvage for severe open tibia fractures, and compare them to equivalent outcomes for unilateral trans-tibial amputees. Cases of severe open diaphyseal tibia fractures sustained in combat between 2006 and 2010, as described in a previously published series, were contacted. Consenting individuals conducted a brief telephone interview and were asked to complete a SF-36 questionnaire. These results were compared to a similar cohort of 18 military patients who sustained a unilateral trans-tibial amputation between 2004 and 2010. Forty-nine patients with 57 severe open tibia fractures met the inclusion criteria. Telephone follow-up and SF-36 questionnaire data was available for 30 patients (61%). The median follow-up was 4 years (49 months, IQR 39-63). Ten of the 30 patients required revision surgery, three of which involved conversion from initial fixation to a circular frame for non- or mal-union. Twenty-two of the 30 patients (73%) recovered sufficiently to complete an age-standardised basic military fitness test. The median physical component score of SF-36 in the limb salvage group was 46 (IQR 35-54) which was similar to the trans-tibial amputation cohort (p=0.3057, Mann-Whitney). Similarly there was no difference in mental component scores between the limb salvage and amputation groups (p=0.1595, Mann-Whitney). There was no significant difference in the proportion of patients in either the amputation or limb salvage group reporting pain (p=0.1157, Fisher's exact test) or with respect to SF-36 physical pain scores (p=0.5258, Mann-Whitney). This study demonstrates that medium term outcomes for military patients are similar following trans-tibial amputation or limb salvage following combat trauma

  14. Direct comparison of polyethylene wear in cemented and uncemented acetabular cups.

    PubMed

    Bjerkholt, Håvard; Høvik, Oystein; Reikerås, Olav

    2010-09-01

    It has been indicated that, in the long term, the rate of wear and the degree of osteolysis observed with uncemented acetabular components are greater than those associated with cemented cups, but most studies which compare the wear characteristics of cementless with cemented cups have used historical controls. We report a direct comparison of wear of a cemented and an uncemented cup with similar design, polyethylene, and sterilization method. The study cohort includes 92 patients who were operated in 1997 with primary total hip replacement and have been followed for a period of 9-10 years. All patients were operated by posterolateral approach. In patients 70 years or older we used a cemented cup, in those 60 years or younger we used an uncemented cup, and in patients between 60 and 70 years we used either a cemented or uncemented cup as decided by the surgeon. At follow-up, radiographic imaging was obtained as standard anterioposterior view of the pelvis, and mean wear was determined as described by Livermore et al. The overall wear of the cemented acetabular components was 1.07 ± 0.78 mm, and that of the uncemented cups was 1.18 ± 0.61 mm (P = 0.529). Wear was significantly associated with male sex (P = 0.003), younger age (P = 0.003), and degree of inclination (P < 0.001), but wear was not significantly associated with cemented versus uncemented cup (P = 0.437). Our findings in this 9-10-year follow-up study suggest that cementless cups wear no more than cemented cups of similar design.

  15. The size of tibial footprint of anterior cruciate ligament and association with physical characteristics in Asian females.

    PubMed

    Park, Yong-Beom; Song, Young-Suk; Kim, Su-Cheol; Park, Yong-Geun; Ha, Chul-Won

    2015-07-01

    The tibial footprint is important for preoperative planning of operative technique and graft selection. Knowledge of tibial footprint in Asians is scant including the relationship between tibial footprint and physical characteristics. The aim of this study was to identify the size of the anterior cruciate ligament (ACL) tibial footprint and the proportion of size <14 mm, and to evaluate the association of tibial footprint with physical characteristics in Asian females. A total of 127 patients with intact or minimal change in ACL were included. The tibial footprint was carefully measured during total knee arthroplasty. As potential predictors, leg length, femoral length, tibial length, and anteroposterior and mediolateral diameter of the proximal tibia were measured on radiographs, as well as body height and weight. The relationship of ACL tibial footprint length <14 mm with physical characteristics was analyzed using univariable and multivariable logistic regression. The tibial footprint was 13.8 mm (range 10.0-18.0) in length and 9.8 mm (range 6.3-13.5) in width. The proportion of footprints <14 mm in length was 53.5 %. Patient height, leg length, femoral length, and tibial length were correlated with tibial footprint. Tibial length was the best predictor of ACL tibial footprint length <14 mm (Odds ratio 1.75; 95 % confidence interval 1.08-2.82). Tibial footprint size shows a large variation with a high proportion of <14 mm length. Tibial length can help predict the ACL tibial footprint in the preoperative planning of ACL reconstruction.

  16. The Visible Cement Data Set

    PubMed Central

    Bentz, Dale P.; Mizell, Symoane; Satterfield, Steve; Devaney, Judith; George, William; Ketcham, Peter; Graham, James; Porterfield, James; Quenard, Daniel; Vallee, Franck; Sallee, Hebert; Boller, Elodie; Baruchel, Jose

    2002-01-01

    With advances in x-ray microtomography, it is now possible to obtain three-dimensional representations of a material’s microstructure with a voxel size of less than one micrometer. The Visible Cement Data Set represents a collection of 3-D data sets obtained using the European Synchrotron Radiation Facility in Grenoble, France in September 2000. Most of the images obtained are for hydrating portland cement pastes, with a few data sets representing hydrating Plaster of Paris and a common building brick. All of these data sets are being made available on the Visible Cement Data Set website at http://visiblecement.nist.gov. The website includes the raw 3-D datafiles, a description of the material imaged for each data set, example two-dimensional images and visualizations for each data set, and a collection of C language computer programs that will be of use in processing and analyzing the 3-D microstructural images. This paper provides the details of the experiments performed at the ESRF, the analysis procedures utilized in obtaining the data set files, and a few representative example images for each of the three materials investigated. PMID:27446723

  17. New radiopaque acrylic bone cement. II. Acrylic bone cement with bromine-containing monomer.

    PubMed

    Rusu, M C; Ichim, I C; Popa, M; Rusu, M

    2008-07-01

    Bromine-containing methacrylate, 2-(2-bromopropionyloxy) ethyl methacrylate (BPEM), had been used in the formulation of acrylic radiopaque cements. The effect of this monomer incorporated into the liquid phase of acrylic bone cement, on the curing parameters, thermal properties, water absorption, density, compression tests and radiopacity was studied. A decrease of maximum temperature and an increase of the setting time were observed with the addition of the bromine-containing monomer in the radiolucent cement composition. Adding BPEM in radiolucent acrylic bone cements composition results in the decrease of glass transition temperature and increase of its thermal stability. Acrylic bone cements modified with bromine-containing comonomer are characterized by polymerization shrinkage lower than the radiolucent cement. Addition of bromine-containing comonomer in radiolucent acrylic bone cement composition determines the increase of compressive strength. Acrylic bone cements modified with bromine-containing comonomer proved to be radiopaque.

  18. Tibial stress injuries. An aetiological review for the purposes of guiding management.

    PubMed

    Beck, B R

    1998-10-01

    In the last 30 years, few advances have been made in the management of tibial stress injuries such as tibial stress fracture and medial tibial stress syndrome (MTSS). Tibial overuse injuries are a recognised complication of the chronic, intensive, weight-bearing training commonly practised by athletic and military populations. Generally, the most effective treatment is considered to be rest, often for prolonged periods. This is a course of action that will significantly disrupt an active lifestyle, and sometimes end activity-related careers entirely. There is now considerable knowledge of the nature of tibial stress injuries, such that presently accepted management practices can be critically evaluated and supplemented. Most recent investigations suggest that tibial stress injuries are a consequence of the repetitive tibial strain imposed by loading during chronic weight-bearing activity. Evidence is presented in this article for an association between repeated tibial bending and stress injury as a function of: (i) strain-related modelling (in the case of MTSS), and (ii) a strain-related positive feedback mechanism of remodelling (in the case of stress fracture). Factors that influence the bending response of the tibia to loading are reviewed. Finally, a guide for injury prevention and management based on research observations is presented.

  19. The incidence and risk factors in the development of medial tibial stress syndrome among naval recruits.

    PubMed

    Yates, Ben; White, Shaun

    2004-01-01

    To identify the incidence of medial tibial stress syndrome (MTSS) in a group of naval recruits undergoing a 10-week basic training period and to determine potential risk factors. One hundred and twenty-four recruits (84 men and 40 women) were followed prospectively during basic training. Anthropometric and lower limb biomechanical data were recorded at the start of the program along with injury history and previous sporting activity for the 3 months prior to enlisting. Recruits were monitored during training for development of medial tibial strees syndrome and were asked to complete an exit interview at the end of the program. Forty recruits (22 men and 18 women) developed medial tibial stress syndrome, giving an incidence of 35%. A significant relationship existed between gender and medial tibial stress syndrome (P =.012), with female recruits more likely to develop medial tibial stress syndrome than male recruits (53% vs 28%). A risk estimate revealed a relative risk of 2.03. The biomechanical results indicated a more pronated foot type (P =.002) in the medial tibial stress syndrome group when compared to the control group. A risk estimate established that recruits with a more pronated foot type had a relative risk of 1.70. Identifying a pronated foot type prior to training may help reduce the incidence of medial tibial stress syndrome by early intervention to control abnormal pronation. Findings of a higher incidence of medial tibial stress syndrome among female recruits require further investigation.

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

    SciTech Connect

    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.

  1. Closed rupture of the posterior tibial artery secondary to a soccer injury.

    PubMed Central

    Tytherleigh, M. G.; Charnley, G. J.; Wilkins, D. C.

    1998-01-01

    Arterial damage following blunt trauma is uncommon and is usually the result of high-energy injury. We report a case of posterior tibial artery rupture after a closed distal tibial fracture, sustained during a low-energy soccer tackle. Images Figure 1 Figure 2 PMID:9771227

  2. Sustainable cement production-present and future

    SciTech Connect

    Schneider, M.; Romer, M.; Tschudin, M.; Bolio, H.

    2011-07-15

    Cement will remain the key material to satisfy global housing and modern infrastructure needs. As a consequence, the cement industry worldwide is facing growing challenges in conserving material and energy resources, as well as reducing its CO{sub 2} emissions. According to the International Energy Agency, the main levers for cement producers are the increase in energy efficiency and the use of alternative materials, be it as fuel or raw materials. Accordingly, the use of alternative fuels has already increased significantly in recent years, but potential for further increases still exists. In cement, the reduction of the clinker factor remains a key priority: tremendous progress has already been made. Nevertheless, appropriate materials are limited in their regional availability. New materials might be able to play a role as cement constituents in the future. It remains to be seen to what extent they could substitute Portland cement clinker to a significant degree.

  3. Calcium sulphate-based cements containing cephalexin.

    PubMed

    Doadrio, J C; Arcos, D; Cabañas, M V; Vallet-Regí, M

    2004-06-01

    Cephalexin containing gypsum and apatite/gypsum cements have been synthesised. The presence of cephalexin into the cements does not alter neither the physico-chemical behaviour of the cements nor produce structural changes on them. These cements behave as drug delivery systems when soaked in simulated body fluid. The release of the drug is different depending on the composition. For gypsum cements, the cephalexin is quickly released, helped by a dissolution process of the matrix, whereas the drug release is more controlled by the hydroxyapatite presence in hydroxyapatite/gypsum samples. Apatite containing cements do not only show a different drug release process, also the paste viscosity is lower and a faster formation "in vitro" of an apatite-type layer on their surface is observed.

  4. Treatment strategy for tibial plateau fractures: an update

    PubMed Central

    Prat-Fabregat, Salvi; Camacho-Carrasco, Pilar

    2016-01-01

    Tibial plateau fractures are complex injuries produced by high- or low-energy trauma. They principally affect young adults or the ‘third age’ population. These fractures usually have associated soft-tissue lesions that will affect their treatment. Sequential (staged) treatment (external fixation followed by definitive osteosynthesis) is recommended in more complex fracture patterns. But one should remember that any type of tibial plateau fracture can present with soft-tissue complications. Typically the Schatzker or AO/OTA classification is used, but the concept of the proximal tibia as a three-column structure and the detailed study of the posteromedial and posterolateral fragment morphology has changed its treatment strategy. Limb alignment and articular surface restoration, allowing early knee motion, are the main goals of surgical treatment. Partially articular factures can be treated by minimally-invasive methods and arthroscopy is useful to assist and control the fracture reduction and to treat intra-articular soft-tissue injuries. Open reduction and internal fixation (ORIF) is the gold standard treatment for these fractures. Complex articular fractures can be treated by ring external fixators and minimally-invasive osteosynthesis (EFMO) or by ORIF. EFMO can be related to suboptimal articular reduction; however, outcome analysis shows results that are equal to, or even superior to, ORIF. The ORIF strategy should also include the optimal reduction of the articular surface. Anterolateral and anteromedial surgical approaches do not permit adequate reduction and fixation of posterolateral and posteromedial fragments. To achieve this, it is necessary to reduce and fix them through specific posterolateral or posteromedial approaches that allow optimal reduction and plate/screw placement. Some authors have also suggested that primary total knee arthroplasty could be an option in specific patients and with specific fracture patterns. Cite this article: Prat

  5. Bilateral transcutaneous tibial nerve stimulation for chronic constipation.

    PubMed

    Iqbal, F; Collins, B; Thomas, G P; Askari, A; Tan, E; Nicholls, R J; Vaizey, C J

    2016-02-01

    Chronic constipation is difficult to treat when symptoms are intractable. Colonic propulsion may be altered by distal neuromodulation but this is conventionally delivered percutaneously. Transcutaneous tibial nerve stimulation is noninvasive and cheap: this study aimed to assess its efficacy in chronic constipation. Eighteen patients (median age 46 years, 12 female) with chronic constipation were recruited consecutively. Conservative and behavioural therapy had failed to improve symptoms in all 18. Thirty minutes of daily bilateral transcutaneous tibial nerve stimulation was administered by each patient at home for 6 weeks. The primary outcome measure was a change in the Patient Assessment of Constipation Quality of Life (PAC-QoL) score. Change in Patient Assessment of Constipation Symptoms (PAC-SYM), weekly bowel frequency and visual analogue scale (VAS) score were also measured. Fifteen patients (12 female) completed the trial. The PAC-QoL score improved significantly with treatment [pretreatment, median 2.95, interquartile range (IQR) 1.18; posttreatment, median 2.50, IQR 0.70; P = 0.047]. There was no change in PAC-SYM score (pretreatment, median 2.36, IQR 1.59; posttreatment, median 2.08, IQR 0.92; P = 0.53). Weekly stool frequency improved as did VAS score, but these did not reach statistical significance (P = 0.229 and 0.161). The PAC-QoL and PAC-SYM scores both improved in four (26%) patients. Two patients reported complete cure. There were no adverse events reported. Bilateral transcutaneous tibial nerve stimulation appears to be effective in a quarter of patients with chronic constipation. Carefully selected patients with less severe disease may benefit more. This requires further study. Colorectal Disease © 2015 The Association of Coloproctology of Great Britain and Ireland.

  6. Medial tibial pain: a dynamic contrast-enhanced MRI study.

    PubMed

    Mattila, K T; Komu, M E; Dahlström, S; Koskinen, S K; Heikkilä, J

    1999-09-01

    The purpose of this study was to compare the sensitivity of different magnetic resonance imaging (MRI) sequences to depict periosteal edema in patients with medial tibial pain. Additionally, we evaluated the ability of dynamic contrast-enhanced imaging (DCES) to depict possible temporal alterations in muscular perfusion within compartments of the leg. Fifteen patients with medial tibial pain were examined with MRI. T1-, T2-weighted, proton density axial images and dynamic and static phase post-contrast images were compared in ability to depict periosteal edema. STIR was used in seven cases to depict bone marrow edema. Images were analyzed to detect signs of compartment edema. Region-of-interest measurements in compartments were performed during DCES and compared with controls. In detecting periosteal edema, post-contrast T1-weighted images were better than spin echo T2-weighted and proton density images or STIR images, but STIR depicted the bone marrow edema best. DCES best demonstrated the gradually enhancing periostitis. Four subjects with severe periosteal edema had visually detectable pathologic enhancement during DCES in the deep posterior compartment of the leg. Percentage enhancement in the deep posterior compartment of the leg was greater in patients than in controls. The fast enhancement phase in the deep posterior compartment began slightly slower in patients than in controls, but it continued longer. We believe that periosteal edema in bone stress reaction can cause impairment of venous flow in the deep posterior compartment. MRI can depict both these conditions. In patients with medial tibial pain, MR imaging protocol should include axial STIR images (to depict bone pathology) with T1-weighted axial pre and post-contrast images, and dynamic contrast enhanced imaging to show periosteal edema and abnormal contrast enhancement within a compartment.

  7. 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

  8. Intraoperative blood pressure changes during cemented versus uncemented bipolar hemiarthroplasty for displaced femoral neck fracture: a multi-center cohort study : The effect of bone cement for bipolar hemiarthroplasty in elderly patients.

    PubMed

    Miyamoto, Shuichi; Nakamura, Junichi; Iida, Satoshi; Shigemura, Tomonori; Kishida, Shunji; Abe, Isao; Takeshita, Munenori; Harada, Yoshitada; Orita, Sumihisa; Ohtori, Seiji

    2017-04-01

    The purpose of this study was to compare the cemented bipolar hemiarthroplasty with uncemented about the change of intraoperative blood pressure and the incidence of major complications in elderly patients with femoral neck fracture. This multiple center prospective cohort study included only patients with acute displaced femoral neck fracture (Garden stage III or IV). All patients were treated with cemented or uncemented bipolar hemiarthroplasty using modified Hardinge or Watson-Jones approach in the lateral decubitus position. Baseline data, medical history, type of anesthesia, FiO 2 value, the number of vasopressor using during operation, femoral component, intraoperative blood pressure, SaO 2 , and major complications were evaluated. Of 164 patients (45 males and 119 females), 86 underwent cemented and 78 underwent uncemented bipolar hemiarthroplasty. Baseline medical histories were similar in both groups. In both the cemented and uncemented groups, intraoperative systolic blood pressure significantly decreased during cementing or rasping (106.3 and 103.6 mmHg) and after femoral component insertion (103.3 and 99.1 mmHg) compared to before rasping (120.7 and 116.4 mmHg) (p < 0.0001, respectively). Donaldson's grade seemed more favorable in uncemented group than in cemented group during cementing or rasping, during stem insertion; however, no patients experienced the lethal complication in both groups. Intraoperative blood pressure did not change during cemented and uncemented bipolar hemiarthrplasty for displaced femoral neck fracture. If the standard modern cement technique was performed during operation, bone cement is a safe and acceptable for elderly patients who have a lot of medical histories.

  9. Return to Sport After Tibial Shaft Fractures: A Systematic Review.

    PubMed

    Robertson, Greg A J; Wood, Alexander M

    2016-07-01

    Acute tibial shaft fractures represent one of the most severe injuries in sports. Return rates and return-to-sport times after these injuries are limited, particularly with regard to the outcomes of different treatment methods. To determine the current evidence for the treatment of and return to sport after tibial shaft fractures. OVID/MEDLINE (PubMed), EMBASE, CINAHL, Cochrane Collaboration Database, Web of Science, PEDro, SPORTDiscus, Scopus, and Google Scholar were all searched for articles published from 1988 to 2014. Inclusion criteria comprised studies of level 1 to 4 evidence, written in the English language, that reported on the management and outcome of tibial shaft fractures and included data on either return-to-sport rate or time. Studies that failed to report on sporting outcomes, those of level 5 evidence, and those in non-English language were excluded. Systematic review. Level 4. The search used combinations of the terms tibial, tibia, acute, fracture, athletes, sports, nonoperative, conservative, operative, and return to sport. Two authors independently reviewed the selected articles and created separate data sets, which were subsequently combined for final analysis. A total of 16 studies (10 retrospective, 3 prospective, 3 randomized controlled trials) were included (n = 889 patients). Seventy-six percent (672/889) of the patients were men, with a mean age of 27.7 years. Surgical management was assessed in 14 studies, and nonsurgical management was assessed in 8 studies. Return to sport ranged from 12 to 54 weeks after surgical intervention and from 28 to 182 weeks after nonsurgical management (mean difference, 69.5 weeks; 95% CI, -83.36 to -55.64; P < 0.01). Fractures treated surgically had a return-to-sport rate of 92%, whereas those treated nonsurgically had a return rate of 67% (risk ratio, 1.37; 95% CI, 1.20 to 1.57; P < 0.01). The general principles are to undertake surgical management for displaced fractures and to attempt nonsurgical

  10. Return to sport following tibial plateau fractures: A systematic review.

    PubMed

    Robertson, Greg A J; Wong, Seng J; Wood, Alexander M

    2017-07-18

    To systemically review all studies reporting return to sport following tibial plateau fracture, in order to provide information on return rates and times to sport, and to assess variations in sporting outcome for different treatment methods. A systematic search of CINAHAL, Cochrane, EMBASE, Google Scholar, MEDLINE, PEDro, Scopus, SPORTDiscus and Web of Science was performed in January 2017 using the keywords "tibial", "plateau", "fractures", "knee", "athletes", "sports", "non-operative", "conservative", "operative", "return to sport". All studies which recorded return rates and times to sport following tibial plateau fractures were included. Twenty-seven studies were included: 1 was a randomised controlled trial, 7 were prospective cohort studies, 16 were retrospective cohort studies, 3 were case series. One study reported on the outcome of conservative management ( n = 3); 27 reported on the outcome of surgical management ( n = 917). Nine studies reported on Open Reduction Internal Fixation (ORIF) ( n = 193), 11 on Arthroscopic-Assisted Reduction Internal Fixation (ARIF) ( n = 253) and 7 on Frame-Assisted Fixation (FRAME) ( n = 262). All studies recorded "return to sport" rates. Only one study recorded a "return to sport" time. The return rate to sport for the total cohort was 70%. For the conservatively-managed fractures, the return rate was 100%. For the surgically-managed fractures, the return rate was 70%. For fractures managed with ORIF, the return rate was 60%. For fractures managed with ARIF, the return rate was 83%. For fractures managed with FRAME was 52%. The return rate for ARIF was found to be significantly greater than that for ORIF (OR 3.22, 95%CI: 2.09-4.97, P < 0.001) and for FRAME (OR 4.33, 95%CI: 2.89-6.50, P < 0.001). No difference was found between the return rates for ORIF and FRAME (OR 1.35, 95%CI: 0.92-1.96, P = 0.122). The recorded return time was 6.9 mo (median), from a study reporting on ORIF. Return rates to sport for tibial plateau

  11. [Structural changes in the tibial bones from an excessive load].

    PubMed

    Moshiashvili, B I

    1977-10-01

    80 cases of pathological reconstruction of the tibia in young men at the age of 18--20 are described. The pathology developed as a result of intense regular physical exercise. In 53 patients the process was localized in the upper third of the tibia, in 20--in the middle third and in 7--in the lower third of the bone. In 6 cases the fracture of the tibial proximal metaphysis happened against the background of pathological reconstruction of the tibia; 3 of them sustained simultaneously a fracture of the fibular head. Some recommendations of practical importance are suggested.

  12. Cement Paste Matrix Composite Materials Center

    DTIC Science & Technology

    1993-11-30

    t/ ,If) , A790/7 (00 Grant No. 90-0242 CEMENT PASTE MATRIX COMPOSITE MATERIALS CENTER I Final Reprt (April 1, 1992 - September 30, 1993) submitted to...Include Security Classification) Cement Paste Matrix Composite Materials Center ( /J 12. PERSONAL AUTHOR(S) J. F. Young 13a. TYPE OF REPORT 13b. TIME...if necessary and identify by block number) Investigations of the development of the microstructure of MDF (Macro-defect-free) cement during processing

  13. Water dynamics in glass ionomer cements

    NASA Astrophysics Data System (ADS)

    Berg, M. C.; Jacobsen, J.; Momsen, N. C. R.; Benetti, A. R.; Telling, M. T. F.; Seydel, T.; Bordallo, H. N.

    2016-07-01

    Glass ionomer cements (GIC) are an alternative for preventive dentistry. However, these dental cements are complex systems where important motions related to the different states of the hydrogen atoms evolve in a confined porous structure. In this paper, we studied the water dynamics of two different liquids used to prepare either conventional or resin-modified glass ionomer cement. By combining thermal analysis with neutron scattering data we were able to relate the water structure in the liquids to the materials properties.

  14. Portland Cement Concrete Recycling: Technology Review.

    DTIC Science & Technology

    1982-01-01

    alternative concrete-mix designs were investigated: 1. Natural coarse and fine aggregates with 20-percent flyash substi- tuted for 15 percent of the...cement. 2. All recycled aggregates. 3. Recycled coarse and natural fine aggregate. 4. Recycled coarse and natural fine aggregate with flyash substituted...for 10 percent of the cement. 5. Recycled coarse and natural fine aggregate with 20-percent flyash substituted for 15 percent of the cement. The

  15. Pulmonary Cement Embolism following Percutaneous Vertebroplasty

    PubMed Central

    Coşkun, Tuba; Acat, Murat; Onaran, Hilal; Gül, Şule; Çetinkaya, Erdoğan

    2014-01-01

    Percutaneous vertebroplasty is a minimal invasive procedure that is applied for the treatment of osteoporotic vertebral fractures. During vertebroplasty, the leakage of bone cement outside the vertebral body leads to pulmonary cement embolism, which is a serious complication of this procedure. Here we report a 48-year-old man who was admitted to our hospital with dyspnea after percutaneous vertebroplasty and diagnosed as pulmonary cement embolism. PMID:25580343

  16. Treating cement burns in the emergency department.

    PubMed

    Summers, Anthony

    2013-03-01

    Use of cement is widespread in the UK and warnings about burns caused by contact with the material are usually printed on bags and delivery dockets. Nevertheless, about 2 per cent of people admitted to burns units have injuries, many serious, caused by prolonged contact with wet cement. This article explores the pathophysiology of cement burns, and outlines the best forms of treatment and prevention.

  17. Reaming Does Not Affect Functional Outcomes After Open and Closed Tibial Shaft Fractures: The Results of a Randomized Controlled Trial.

    PubMed

    Lin, Carol A; Swiontkowski, Marc; Bhandari, Mohit; Walter, Stephen D; Schemitsch, Emil H; Sanders, David; Tornetta, Paul

    2016-03-01

    We sought to determine the effect of reaming on 1-year 36-item short-form general health survey (SF-36) and short musculoskeletal function assessment (SMFA) scores from the Study to Prospectively Evaluate Reamed Intramedullary Nails in patients with Tibial Fractures. Prospective randomized controlled trial.1319 patients were randomized to reamed or unreamed nails. Fractures were categorized as open or closed. Twenty-nine academic and community health centers across the US, Canada, and the Netherlands. One thousand three hundred and nineteen skeletally mature patients with closed and open diaphyseal tibia fractures. Reamed versus unreamed tibial nails. SF-36 and the SMFA. Outcomes were obtained during the initial hospitalization to reflect preinjury status, and again at the 2-week, 3-month, 6-month, and 1-year follow-up. Repeated measures analyses were performed with P < 0.05 considered significant. There were no differences between the reamed and unreamed groups at 12 months for either the SF-36 physical component score [42.9 vs. 43.4, P = 0.54, 95% Confidence Interval for the difference (CI) -2.1 to 1.1] or the SMFA dysfunction index (18.0 vs. 17.6, P = 0.79. 95% CI, -2.2 to 2.9). At one year, functional outcomes were significantly below baseline for the SF-36 physical componentf score, SMFA dysfunction index, and SMFA bothersome index (P < 0.001). Time and fracture type were significantly associated with functional outcome. Reaming does not affect functional outcomes after intramedullary nailing for tibial shaft fractures. Patients with open fractures have worse functional outcomes than those with a closed injury. Patients do not reach their baseline function by 1 year after surgery. Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

  18. Tibial stress fractures in an active duty population: long-term outcomes.

    PubMed

    Kilcoyne, Kelly G; Dickens, Jonathan F; Rue, John-Paul

    2013-01-01

    Tibial stress fractures are a common overuse injury among military recruits. The purpose of this study was to determine what, if any, long-term effects that tibial stress fractures have on military personnel with respect to physical activity level, completion of military training, recurrence of symptoms, and active duty service. Twenty-six military recruits included in a previous tibial stress fracture study were contacted 10 years after initial injury and asked a series of questions related to any long-term consequences of their tibial stress fracture. Of the 13 patients available for contact, no patients reported any necessary limited duty while on active duty, and no patient reported being separated or discharged from the military as a result of stress fracture. Tibial stress fractures in military recruits are most often an isolated injury and do not affect ability to complete military training or reflect a long-term need for decreased physical activity.

  19. Non-invasive repair of an iatrogenic tibial artery branch pseudoaneurysm after intramedullary nailing.

    PubMed

    Hanson, Cameron G; Hanson, Logan F

    2017-11-01

    Tibial fractures are a commonly seen injury in orthopedic surgery. Intramedullary nailing is considered the standard of care, as complications are rare. Those of a vascular nature, including iatrogenically induced pseudoaneurysms of the tibial artery have been previously described in the literature, however each reported case has required surgical repair. In the current case, we describe a repair of a tibial artery branch pseudoaneurysm, after direct contact with an interlocking screw from tibial intramedullary nailing, via ultrasound-guided thrombin injection. To the authors' knowledge, this is the first reported case of a tibial artery pseudoaneurysm repaired non-surgically. This adds support to the promising literature on non-invasive repair of orthopedically related pseudoaneurysms.

  20. Postoperative Repeat Dislocation of the Posterior Tibial Tendon: A Case Report.

    PubMed

    Ikuta, Yasunari; Adachi, Nobuo; Nakasa, Tomoyuki; Ochi, Mitsuo

    Dislocation of the posterior tibial tendon is an uncommon condition. Although surgery is usually performed in most cases of posterior tibial tendon dislocation, postoperative repeat dislocation of the posterior tibial tendon has not been reported in the published data. We report the case of a 27-year-old male patient who experienced repeat dislocation of the posterior tibial tendon after a gymnastic landing, 44 months after initial retinaculum repair. For revision surgery, we reconstructed the flexor retinaculum in conjunction with deepening of the retromalleolar groove, because the groove was hypoplastic. He returned to competitive gymnastics and had not experienced subluxation or dislocation of the posterior tibial tendon at the 1-year follow-up examination. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  1. Nanofunctionalized zirconia and barium sulfate particles as bone cement additives.

    PubMed

    Gillani, Riaz; Ercan, Batur; Qiao, Alex; Webster, Thomas J

    2010-02-02

    Zirconia (ZrO(2)) and barium sulfate (BaSO(4)) particles were introduced into a methyl methacrylate monomer (MMA) solution with polymethyl methacrylate (PMMA) beads during polymerization to develop the following novel bone cements: bone cements with unfunctionalized ZrO(2) micron particles, bone cements with unfunctionalized ZrO(2) nanoparticles, bone cements with ZrO(2) nanoparticles functionalized with 3-(trimethoxysilyl)propyl methacrylate (TMS), bone cements with unfunctionalized BaSO(4) micron particles, bone cements with unfunctionalized BaSO(4) nanoparticles, and bone cements with BaSO(4) nanoparticles functionalized with TMS. Results demonstrated that in vitro osteoblast (bone-forming cell) densities were greater on bone cements containing BaSO(4) ceramic particles after four hours compared to control unmodified bone cements. Osteoblast densities were also greater on bone cements containing all of the ceramic particles after 24 hours compared to unmodified bone cements, particularly those bone cements containing nanofunctionalized ceramic particles. Bone cements containing ceramic particles demonstrated significantly altered mechanical properties; specifically, under tensile loading, plain bone cements and bone cements containing unfunctionalized ceramic particles exhibited brittle failure modes whereas bone cements containing nanofunctionalized ceramic particles exhibited plastic failure modes. Finally, all bone cements containing ceramic particles possessed greater radio-opacity than unmodified bone cements. In summary, the results of this study demonstrated a positive impact on the properties of traditional bone cements for orthopedic applications with the addition of unfunctionalized and TMS functionalized ceramic nanoparticles.

  2. In vivo evaluation of femoral and tibial graft tunnel placement following all-inside arthroscopic tibial inlay reconstruction of the posterior cruciate ligament.

    PubMed

    Osti, Michael; Krawinkel, Alessa; Benedetto, Karl Peter

    2014-12-01

    The arthroscopic all-inside tibial inlay technique represents a novel procedure for posterior cruciate ligament (PCL) reconstruction. However, in vivo investigations that evaluate the accuracy of this technique regarding anatomic graft tunnel placement are few. The objective of this study was to analyse the femoral and tibial tunnel apertures using computed tomography (CT) and compare these findings to recommendations in the literature. CT scans were obtained in 45 patients following single-bundle PCL reconstruction. The centres of the tibial and femoral tunnel apertures were correlated to measurement grid systems used as a radiographic reference. The centre of the femoral tunnel aperture was located at 42.9% ± 9.4% of the total intercondylar depth and at 12.9% ± 7.2% of the total intercondylar height. The angle α for the femoral tunnel position was measured at 64.2° ± 10.0°. The centre of the tibial tunnel aperture was found at 51.8% ± 4.1% of the total mediolateral diameter of the tibial plateau. The superoinferior distance of the tibial tunnel aperture to the joint line was 9.6 mm ± 4.4 mm on frontal and 9.3 mm ± 3.4 mm on sagittal 3D-CT scans. The distance of the tibial tunnel aperture to the former physis line averaged to 0.8 mm ± 3.4 mm. Comparison to the corresponding reference values revealed no statistically significant difference. Arthroscopic tibial inlay reconstruction is an efficient procedure for precise replication of the anatomical footprint of the PCL. IV, prospective case series. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Test using expansive cement in cement stabilized base to eliminate or prevent cracking : experimental projects.

    DOT National Transportation Integrated Search

    1975-08-01

    The purpose of this study was to determine the feasibility of using an : expansive cement, TXI 4C Chem Comp, in lieu of the regular Type I Portland : Cement in a cement stabilized gravel screenings base so as to eliminate : or reduce cracks associate...

  4. The effect of low dose teicoplanin-loaded acrylic bone cement on biocompatibility of bone cement.

    PubMed

    Öztemür, Zekeriya; Sümer, Zeynep; Tunç, Tutku; Pazarcé, Özhan; Bulut, Okay

    2013-06-01

    Antibiotic-loaded acrylic bone cement (polymethylmethacrylate, PMMA) is used to prevent or treat infection in total joint replacement surgery. The purpose of this study was to investigate biocompatibility and cytotoxicity of the teicoplanin-loaded acrylic bone cement. Cytotoxicity examination of acrylic bone cement balls and 400 mg teicoplanin added acrylic bone cement balls conducted by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. SEM (Scanning electron microscopy) was used to observe adhesion and spreading of cells on surface of the balls. Cytotoxicity examination conducted by MTT assay on acrylic bone cement balls and teicoplanin-added acrylic bone cement balls revealed no cytotoxicity. SEM analysis put forward that cells started to proliferate and adhere on surface of the samples in both groups as a result of 48-hour incubation and that the cell proliferation over acrylic bone cement and teicoplanin-added acrylic bone cement was similar. As a consequence, there was no cytotoxicity in acrylic bone cement and teicoplanin-added acrylic bone cement groups according to results of MTT assay. On the other hand, results of SEM showed that biocompatibility of both groups was similar. In conclusion, teicoplanin-loaded bone cement did not change biocompatibility of bone cement in studied dose.

  5. Constraining the Texture and Composition of Pore-Filling Cements at Gale Crater, Mars

    NASA Technical Reports Server (NTRS)

    Siebach, K. L.; Grotzinger, J. P.; McLennan, S. M.; Hurowitz, J. A.; Ming, D. W.; Vaniman, D. T.; Rampe, E. B.; Blaney, D. L.; Kah, L. C.

    2015-01-01

    The Mars Science Laboratory (MSL) rover Curiosity has encountered a wide variety of sedimentary rocks deposited in fluvio-lacuestrine sequences at the base of Gale Crater. The presence of sedimentary rocks requires that initial sediments underwent diagenesis and were lithified. Lithification involves sediment compaction, cementation, and re-crystallization (or authigenic) processes. Analysis of the texture and composition of the cement can reveal the environmental conditions when the cements were deposited, enabling better understanding of early environments present within Gale Crater. The first step in lithification is sediment compaction. The Gale crater sediments do not show evidence for extensive compaction prior to cementation; the Sheepbed mudstone in Yellowknife Bay (YKB) has preserved void spaces ("hollow nodules"), indicating that sediments were cemented around the hollow prior to compaction, and conglomerates show imbrication, indicating minimal grain reorganization prior to lithification. Furthermore, assuming the maximum burial depth of these sediments is equivalent to the depth of Gale Crater, the sediments were never under more than 1 kb of pressure, and assuming a 15 C/km thermal gradient in the late Noachian, the maximum temperature of diagenesis would have been approximately 75 C. This is comparable to shallow burial diagenetic conditions on Earth. The cementation and recrystallization components of lithification are closely intertwined. Cementation describes the precipitation of minerals between grains from pore fluids, and recrystallization (or authigenesis) is when the original sedimentary mineral grains are altered into secondary minerals. The presence of authigenic smectites and magnetite in the YKB formation suggests that some recrystallization has taken place. The relatively high percentage of XRD-amorphous material (25-40%) detected by CheMin suggests that this recrystallization may be limited in scope, and therefore may not contribute

  6. Integer programming of cement distribution by train

    NASA Astrophysics Data System (ADS)

    Indarsih

    2018-01-01

    Cement industry in Central Java distributes cement by train to meet daily demand in Yogyakarta and Central Java area. There are five destination stations. For each destination station, there is a warehouse to load cements. Decision maker of cement industry have a plan to redesign the infrastructure and transportation system. The aim is to determine how many locomotives, train wagons, and containers and how to arrange train schedules with subject to the delivery time. For this purposes, we consider an integer programming to minimize the total of operational cost. Further, we will discuss a case study and the solution the problem can be calculated by LINGO software.

  7. Cement Paste Matrix Composite Materials Center.

    DTIC Science & Technology

    1987-10-01

    Materials .. QI-DF Cement’s 11.6 Cement Pastes 4t v-".~A(-- 19 AffSTkC (Continue on reverse if necessary and identify by block number) )The report...describes the firsL year implementation of the Center for Excellence on Cement Paste Matrix Composite Materials. Topics include organization and...Contract: F49620-87-C-0023 CEMENT PASTE MATRIX COMPOSITE MATERIALS CENTER Forst Annual Report (29 October 1986 -29 October 1987) submitted to U. S. Air

  8. Proper selection of contemporary dental cements.

    PubMed

    Yu, Hao; Zheng, Ming; Chen, Run; Cheng, Hui

    2014-03-01

    Today proper selection of dental cements is a key factor to achieve a successful restoration and will greatly increase the chances of long-term success of the restoration. In recent years, many newly formulated dental cements have been developed with the claim of better performance compared to the traditional materials. Unfortunately, selection of suitable dental cement for a specific clinical application has become increasingly complicated, even for the most experienced dentists. The purpose of this article is to review the currently existing dental cements and to help the dentists choose the most suitable materials for clinical applications.

  9. Substantial global carbon uptake by cement carbonation

    NASA Astrophysics Data System (ADS)

    Xi, Fengming; Davis, Steven J.; Ciais, Philippe; Crawford-Brown, Douglas; Guan, Dabo; Pade, Claus; Shi, Tiemao; Syddall, Mark; Lv, Jie; Ji, Lanzhu; Bing, Longfei; Wang, Jiaoyue; Wei, Wei; Yang, Keun-Hyeok; Lagerblad, Björn; Galan, Isabel; Andrade, Carmen; Zhang, Ying; Liu, Zhu

    2016-12-01

    Calcination of carbonate rocks during the manufacture of cement produced 5% of global CO2 emissions from all industrial process and fossil-fuel combustion in 2013. Considerable attention has been paid to quantifying these industrial process emissions from cement production, but the natural reversal of the process--carbonation--has received little attention in carbon cycle studies. Here, we use new and existing data on cement materials during cement service life, demolition, and secondary use of concrete waste to estimate regional and global CO2 uptake between 1930 and 2013 using an analytical model describing carbonation chemistry. We find that carbonation of cement materials over their life cycle represents a large and growing net sink of CO2, increasing from 0.10 GtC yr-1 in 1998 to 0.25 GtC yr-1 in 2013. In total, we estimate that a cumulative amount of 4.5 GtC has been sequestered in carbonating cement materials from 1930 to 2013, offsetting 43% of the CO2 emissions from production of cement over the same period, not including emissions associated with fossil use during cement production. We conclude that carbonation of cement products represents a substantial carbon sink that is not currently considered in emissions inventories.

  10. Tibial dyschondroplasia is highly associated with suppression of tibial angiogenesis through regulating the HIF-1α/VEGF/VEGFR signaling pathway in chickens.

    PubMed

    Huang, Shu-Cheng; Rehman, Mujeeb Ur; Lan, Yan-Fang; Qiu, Gang; Zhang, Hui; Iqbal, Muhammad Kashif; Luo, Hou-Qiang; Mehmood, Khalid; Zhang, Li-Hong; Li, Jia-Kui

    2017-08-22

    Tibial dyschondroplasia (TD) is an intractable poultry problem that is characterized by the appearance of non-vascularized and non-mineralized cartilage masses in tibial growth plates (TGPs). However, the role of angiogenesis inhibition in the occurrence of TD remains unknown. In this study, we found that, compared to low-altitude Arbor Acres chickens (AACs), high-altitude Tibetan chickens showed higher tibial vascular distributions that were accompanied by up-regulation of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor A (VEGFA) and VEGF receptors. These observations provide insights into hypoxia-induced angiogenesis, which may be related to the absence of TD in high-altitude native Tibetan chickens. Importantly, hypoxia experiments also showed that during hypoxia, tibial angiogenesis was enhanced, which was due to pro-angiogenic factor up-regulation (including VEGFA, VEGFR1, VEGFR2, and IL-8), in AACs. Moreover, we observed that thiram-induced TD could strongly inhibit tibial angiogenesis in the hypertrophic zone through coordinated down-regulation of HIF-1α and pro-angiogenic factors, leading to a disruption in the blood supply to the TGP. Taken together, these findings reveal that the occurrence of TD is highly associated with inhibition of tibial angiogenesis through down-regulated expression of HIF-1α, VEGFA and VEGF receptors, which results in suppression of TGP development.

  11. Comparison of locking and conventional screws for maintenance of tibial plateau positioning and biomechanical stability after locking tibial plateau leveling osteotomy plate fixation.

    PubMed

    Leitner, Michael; Pearce, Simon G; Windolf, Markus; Schwieger, Karsten; Zeiter, Stephan; Schawalder, Peter; Johnson, Kenneth A

    2008-06-01

    To compare locking screws with conventional screws inserted in the tibial plateau fragment for reduction and stability of the construct after tibial plateau leveling osteotomy (TPLO), using a locking TPLO plate. Experimental biomechanical study. Cadaveric canine pelvic limbs (n=8 pairs). TPLO was stabilized with either conventional cortical screws or locking screws in a compressed osteotomy model. Titanium pins inserted into the tibial plateau and proximal metaphysis were used to track bone fragment location by computed tomography (CT) imaging. CT imaging was performed after osteotomy reduction, after plate stabilization, and after 30,000 cycles of axial compression testing. After 30,000 cycles, cyclic loading was continued with monotonically increasing peak-load until failure. The magnitude of rotation about the sawing axis was significantly greater for the conventional screw group because of plate application (P=.009). Translational movement of the tibial plateau fragment toward the plate was significantly greater for the conventional screw group (P=.006). There were no significant differences between groups in stiffness or number of cycles to failure. Maintenance of tibial plateau position was significantly superior for the locking screw group during plate application; however, screw type had no effect on fixation stability under cyclic loading. These results suggest that conventional screws and careful contouring of the TPLO plate can provide comparable mechanical stability to fixation with locking screws in the tibial plateau under load-sharing conditions, but potentially at the expense of osteotomy reduction.

  12. Canine Stifle Biomechanics Associated With Tibial Tuberosity Advancement Predicted Using a Computer Model.

    PubMed

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

    2015-10-01

    To evaluate the effects of tibial tuberosity advancement (TTA) on canine biomechanics in the cranial cruciate ligament (CrCL)-deficient stifle using a 3-dimensional quasi-static rigid body pelvic limb computer model simulating the stance phase of gait. Computer simulations. A 5-year-old neutered male Golden Retriever weighing 33 kg. A TTA was implemented in a previously developed canine pelvic limb computer model using the tibial plateau slope and common tangent planning techniques. Ligament loads, relative tibial translation, and relative tibial rotation were determined and compared to CrCL-intact and CrCL-deficient stifles. The TTA significantly decreased peak caudal cruciate ligament load, significantly increased peak lateral collateral ligament load, and significantly changed peak medial collateral ligament load occurrence, while there was no significant difference in peak patellar ligament load compared to the CrCL-intact stifle. Compared to the CrCL-deficient stifle, peak caudal cruciate, lateral collateral and medial collateral ligament loads significantly decreased, while peak patellar ligament load was similar, peak relative tibial translation significantly decreased and peak relative tibial rotation was converted to external rotation in the TTA-treated stifle. Each TTA planning technique generated similar caudal cruciate, medial collateral, and patellar ligament loading as well as relative tibial translation, but lateral collateral ligament loading and occurrence of relative tibial rotation differed significantly across the techniques. Model-predicted stifle ligament loads improved following TTA compared to the CrCL-deficient stifle, but TTA did not restore CrCL-intact stifle biomechanics. The TTA effectively reduced tibial translation, but tibial rotation was not stabilized. © Copyright 2015 by The American College of Veterinary Surgeons.

  13. Is posterior tibial slope associated with noncontact anterior cruciate ligament injury?

    PubMed

    Zeng, Chao; Yang, Tuo; Wu, Song; Gao, Shu-guang; Li, Hui; Deng, Zhen-han; Zhang, Yi; Lei, Guang-hua

    2016-03-01

    This study aimed to: (1) examine whether the association between posterior tibial slope and noncontact ACL injury exists in Chinese population; (2) compare the reliability and consistency of the three methods (longitudinal axis, posterior and anterior tibial cortex axis) in lateral radiograph. Case-control study contained 146 patients in total (73 noncontact ACL injuries and 73 meniscus injuries, matched for age and gender), which were verified by arthroscopy, MRI and physical examination. For the total population and the male subgroup, the mean posterior tibial slope of the ACL-injured group was significantly higher than that of the control group (P < 0.001). In addition, the longitudinal axis method exhibited the highest inter-rater (0.898) and intrarater reliability (0.928), whereas the anterior tibial cortex was the most variable (inter-rater reliability, 0.805; intrarater reliability, 0.824). The anterior tibial cortex method produced largest posterior tibial slope measurements (13.8 ± 3.3 for injury group; 11.6 ± 2.7 for control group), while the posterior tibial cortex method was the smallest (9.1 ± 3.1 for injury group; 7.2 ± 2.6 for control group). All three methods were not affected by age, sex, height, weight and BMI (n.s.). The results of this study suggested that an increased posterior tibial slope was associated with the risk of noncontact ACL injury in Chinese population. Meanwhile, the longitudinal axis method is recommended for measuring posterior tibial slope in lateral radiograph in future studies. Posterior tibial slope measured by longitudinal axis method may be used as predictor of ACL injury. Case-control study, Level III.

  14. Development and validation of a new method for the radiologic measurement of the tibial slope.

    PubMed

    Utzschneider, S; Goettinger, M; Weber, P; Horng, A; Glaser, C; Jansson, V; Müller, P E

    2011-10-01

    The posterior tibial slope has a huge influence on the kinematics of the knee. In several orthopedic interventions such as high tibial osteotomy and unicondylar or bicondylar knee replacement changing, the tibial slope can result in altered knee mechanics. Therefore, an exact preoperative measurement of the posterior tibial slope is mandatory. Several methods are used on conventional radiographs and CT scans, but until now there is no standard validated method. The aim of this study was to compare several methods and imaging techniques to measure the posterior tibial slope and to establish a standard and reliable measurement method by radiography. Fourteen knees (seven cadavers) were scanned by a 64-slice CT, a 3T-MRI, and true lateral radiographs were performed. The anatomical references (TPAA = tibial proximal anatomical axis; ATC = anterior tibial cortex; PTC = posterior tibial cortex) and the new computed reference (MPA = mean of PTA and ATC) were compared by short as well as long radiographs, CT scan and MRI. The influence of a malrotation in radiographs of the knees was also analyzed. CT scan and MRI are suitable for the measurement of the medial and lateral posterior tibial slopes, the results of the radiographs varied depending on the method used. The new method (MPA) showed the best correlation to the CT scan (r = 0.997), even on short radiographs (10 cm distal the joint line). The measurement of the posterior tibial slope on a short lateral radiograph using the MPA is a reliable method and should be established as a standard. Diagnostic study, Level II.

  15. Surgical management of persistent intoeing gait due to increased internal tibial torsion in children.

    PubMed

    Davids, Jon R; Davis, Roy B; Jameson, Lisa C; Westberry, David E; Hardin, James W

    2014-06-01

    Intoeing gait is frequently seen in developing children, and in most cases it resolves with growth. However, persistent, extreme intoeing gait, due to increased internal tibial torsion, may disrupt gait function. At our institution, children with symptomatic intoeing gait are evaluated per a standardized protocol, which includes quantitative gait analysis. When the primary cause is increased internal tibial torsion, surgical correction by supramalleolar tibial rotational osteotomy is recommended. The study design was a retrospective case series, with normative controls (31 children), of typically developing children with symptomatic intoeing gait who were treated by isolated supramalleolar tibial rotation osteotomy (28 children, with 45 treated extremities). Preoperative and 1-year postoperative physical examination, kinematic, kinetic, and pedobarographic data were compared. Patient-reported and parent-reported outcomes in functional and satisfaction domains were assessed by items on a 7-point questionnaire. Internal tibial torsion, foot progression angle, and knee rotation were normalized following tibial rotation osteotomy. Compensatory external hip rotation and external knee progression angle were significantly improved but not normalized following tibial rotation osteotomy. An increased coronal plane knee varus moment was significantly decreased following surgery. Increased sagittal and transverse plane knee moments were significantly decreased but not normalized following surgery. Significant improvements were observed with respect to tripping, falling, foot/ankle pain, and knee pain following surgery. Children with symptomatic intoeing gait because of increased internal tibial torsion have characteristic primary and compensatory kinematic gait deviations that result in increased loading about the knee during the stance phase of gait. Correction of the internal tibial torsion by rotation osteotomy improves, but does not normalize, all the kinematic and

  16. Effect of temporary cements on the shear bond strength of luting cements

    PubMed Central

    FIORI-JÚNIOR, Marco; MATSUMOTO, Wilson; SILVA, Raquel Assed Bezerra; PORTO-NETO, Sizenando Toledo; SILVA, Jaciara Miranda Gomes

    2010-01-01

    Objective The purpose of this study was to evaluate, by shear bond strength (SBS) testing, the influence of different types of temporary cements on the final cementation using conventional and self-etching resin-based luting cements. Material and Methods Forty human teeth divided in two halves were assigned to 8 groups (n=10): I and V (no temporary cementation); II and VI: Ca(OH)2-based cement; III and VII: zinc oxide (ZO)based cement; IV and VIII: ZO-eugenol (ZOE)-based cement. Final cementation was done with RelyX ARC cement (groups I to IV) and RelyX Unicem cement (groups V to VIII). Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. Results Means were (MPa): I - 3.80 (±1.481); II - 5.24 (±2.297); III - 6.98 (±1.885); IV - 6.54 (±1.459); V - 5.22 (±2.465); VI - 4.48 (±1.705); VII - 6.29 (±2.280); VIII - 2.47 (±2.076). Comparison of the groups that had the same temporary cementation (Groups II and VI; III and VII; IV and VIII) showed statistically significant difference (p<0.001) only between Groups IV and VIII, in which ZOE-based cements were used. The use of either Ca(OH)2 based (Groups II and VI) or ZO-based (Groups III and VII) cements showed no statistically significant difference (p>0.05) for the different luting cements (RelyXTM ARC and RelyXTM Unicem). The groups that had no temporary cementation (Groups I and V) did not differ significantly from each other either (p>0.05). Conclusion When temporary cementation was done with ZO- or ZOE-based cements and final cementation was done with RelyX ARC, there was an increase in the SBS compared to the control. In the groups cemented with RelyX Unicem, however, the use of a ZOE-based temporary cement affected negatively the SBS of the luting agent used for final cementation. PMID:20379679

  17. A study on provisional cements, cementation techniques, and their effects on bonding of porcelain laminate veneers.

    PubMed

    Vinod Kumar, G; Soorya Poduval, T; Bipin Reddy; Shesha Reddy, P

    2014-03-01

    Minimal tooth preparation is required for porcelain laminate veneers, but interim restorations are a must to protect their teeth against thermal insult, chemical irritation, and to provide aesthetics. Cement remaining after the removal of the provisional restoration can impair the etching quality of the tooth surface and fit and final bonding of the porcelain laminate veneer. This in vitro study examined the tooth surface for remaining debris of cement after removal of a provisional restoration. Determine the presence of cement debris on prepared tooth surface subsequent to the removal of provisional restoration. Determine the cement with the least residue following the cleansing procedures. Determine the effect of smear layer on the amount of residual luting cement. Eighty-four extracted natural anterior teeth were prepared for porcelain laminate veneers. For half of the teeth, the smear layer was removed before luting provisional restorations. Veneer provisional restorations were fabricated and luted to teeth with six bonding methods: varnish combined with glass ionomer cement (GIC), varnish combined with resin modified GIC, varnish, spot etching combined with dual-cure luting cement, adhesive combined with GIC, adhesive combined with resin modified GIC, and adhesive, spot etching combined with dual-cure luting cement. After removal of provisional restorations 1 week later, the tooth surface was examined for residual luting material with SEM. Traces of cement debris were found on all the prepared teeth surfaces for all six groups which were cemented with different methods. Cement debris was seen on teeth subsequent to the removal of provisional's. Dual-cure cement had the least residue following the cleansing procedures. Presence of smear layer had no statistical significance in comparison with cement residue. With the use of adhesive the cement debris was always found to be more than with the use of varnish. GIC showed maximum residual cement followed by dual-cure.

  18. Effect of interstitial low level laser therapy on tibial defect

    NASA Astrophysics Data System (ADS)

    Lee, Sangyeob; Ha, Myungjin; Hwang, Donghyun; Yu, Sungkon; Jang, Seulki; Park, Jihoon; Radfar, Edalat; Kim, Hansung; Jung, Byungjo

    2016-03-01

    Tibial defect is very common musculoskeletal disorder which makes patient painful and uncomfortable. Many studies about bone regeneration tried to figure out fast bone healing on early phase. It is already known that low level laser therapy (LLLT) is very convenient and good for beginning of bone disorder. However, light scattering and absorption obstruct musculoskeletal therapy which need optimal photon energy delivery. This study has used an interstitial laser probe (ILP) to overcome the limitations of light penetration depth and scattering. Animals (mouse, C57BL/6) were divided into three groups: laser treated test group 1 (660 nm; power 10 mW; total energy 5 J) and test group 2 (660 nm; power 20 mW; total energy 10 J); and untreated control group. All animals were taken surgical operation to make tibial defect on right crest of tibia. The test groups were treated every 48 hours with ILP. Bone volume and X-ray attenuation coefficient were measured on 0, 14th and 28th day with u-CT after treatment and were used to evaluate effect of LLLT. Results show that bone volume of test groups has been improved more than control group. X-ray attenuation coefficients of each groups have slightly different. The results suggest that LLLT combined with ILP may affect on early phase of bone regeneration and may be used in various musculoskeletal disease in deep tissue layer.

  19. [Posterior tibial nerve stimulation for pelvic floor dysfunction. Review].

    PubMed

    Sucar-Romero, Sandra; Escobar-del Barco, Laura; Rodríguez-Colorado, Silvia; Gorbea-Chávez, Viridiana

    2014-08-01

    Pelvic floor dysfunction is a highly prevalent functional pathology that affects women and can present with different clinical symptoms that include urinary urgency with or without incontinence, diurnal and nocturnal frequency, urinary retention, fecal incontinence, obstructive defecation, sexual dysfunction and pelvic pain. Lately, concern arised as to offer patients an advanced therapy within an integral approach. This interest was first focused in sacral nerve root modulation, a key element for pelvic function. Neuromodulation is considered a normal characteristic of the nervous system that regulates or modifies the electric impulses that come from different nervous body tissues. Neuromodulation is carried out through sacral neurostimulation (SNS), posterior tibial nerve stimulation (PNTS), which are reversible non destructive therapies used for peripheric stimulation of nerves, ganglia, spinal medula and brain. Even though there is evidence of efficacy for sacral nerve stimulation at short, medium and long-term, there are two main concerns within this approach: invasivity and high cost. It seems posterior nerve tibial stimulation has the same neuromodulatory effect as the one obtained by sacral nerve stimulation through a less invasive route and lower cost.

  20. Radiographic predictors of compartment syndrome in tibial plateau fractures.

    PubMed

    Ziran, Bruce H; Becher, Stephen John

    2013-11-01

    The purpose of this article was to evaluate the relationship of radiographic features of tibial plateau fractures to the development of compartment syndrome. We hypothesized that the direction and degree of initial displacement of the femur on the tibia, and the amount of tibial widening (TW), were correlated with the development of compartment syndrome. Retrospective case-control study. Single level 1 trauma center. Retrospective evaluation of 158 patients with 162 plateau fractures. Grouping with and without compartment syndrome. The following data were obtained: age, sex, Schatzker and OTA/AO classification, open/closed status, TW, and femoral displacement (FD). A univariate statistical and a logistical regression analysis were performed to determine significance. The overall rate of compartment syndrome was 11%. Univariate analysis found both the TW and FD to be significant with respect to development of compartment syndrome (P < 0.05). Higher Schatzker (IV-VI) and OTA/AO grades were also correlated (P < 0.05) with increased incidence of compartment syndrome. Logistic regression found FD and Schatzker grade to be significant. Our study is the first to identify easily obtained radiographic parameters that correlate to the occurrence compartment syndrome. There may also be a relationship between TW and FD, as noted by regression result. This study helps to assess which patients with a fracture are at higher risk for developing a compartment syndrome. Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

  1. A New Instrument for Measuring Tibial Torsion in Pediatric Patients

    PubMed Central

    2017-01-01

    Objective To develop and test the validity and reliability of a new instrument for measuring the thigh-foot angle (TFA) for the patients with in-toeing and out-toeing gait. Methods The new instrument (Thigh-Foot Supporter [TFS]) was developed by measuring the TFA during regular examination of the tibial torsional status. The study included 40 children who presented with in-toeing and out-toeing gaits. We took a picture of each case to measure photographic-TFA (P-TFA) in the proper position and to establish a criterion. Study participants were examined by three independent physicians (A, B, and C) who had one, three and ten years of experience in the field, respectively. Each examiner conducted a separate classical physical examination (CPE) of every participant using a gait goniometer followed by a TFA assessment of each pediatric patient with or without the TFS. Thirty minutes later, repeated in the same way was measured. Results Less experienced examiner A showed significant differences between the TFA values depending on whether TFS used (left p=0.003 and right p=0.008). However, experienced examiners B and C did not show significant differences. Using TFS, less experienced examiner A showed a high validity and all examiner's inter-test and the inter-personal reliabilities increased. Conclusion TFS may increase validity and reliability in measuring tibial torsion in patients who has a rotational problem in lower extremities. It would be more useful in less experienced examiners. PMID:28758082

  2. Antibacterial activity of selected glass ionomer cements.

    PubMed

    Luczaj-Cepowicz, Elżbieta; Marczuk-Kolada, Grażyna; Zalewska, Anna; Pawińska, Małgorzata; Leszczyńska, Katarzyna

    2014-01-22

    The aim of the paper was to determine the antibacterial activity of four glass ionomer cements against bacteria of the genera Streptococcus and Lactobacillus. Four capsulated glass ionomer cements were applied in the study: Fuji Triage (GC), Fuji IX (GC), Ketac Molar (3M Espe) and Ketac Silver (3M Espe). Four standard bacterial strains were used to assess the antibacterial activity of the studied cements: Streptococcus mutans, S. sanguis, S. salivarius and Lactobacillus casei. The antibacterial activity was determined by the agar diffusion method. The bacterial suspension was spread with a cotton swab on TSA plates. For each material six wells (7 mm diameter, 5 mm deep) were made with a cork borer. Each well was then filled with freshly prepared cements. The results were obtained by measuring the bacterial growth inhibition zone after 1, 2, 3 and 7 days. Fuji Triage cement inhibited the growth of all bacterial strains. Fuji IX cement demonstrated the most potent antibacterial activity against S. sanguis. Ketac Molar showed antibacterial activity against S. sanguis and S. salivarius, whereas Ketac Silver was efficient against S. mutans as well. Neither of the Ketac cements inhibited growth of the standard L. casei strain. Antibacterial activity of glass ionomer cements has attracted the interest of scientists in recent years. Most authors, including us, carried out experiments using the agar diffusion method and demonstrated antibacterial activity of glass ionomer cements. Different antibacterial activity of glass ionomer cements, observed in our study and studies of other authors, depended on the evaluated cement, bacterial strain and period of evaluation.

  3. Fluoroscopic Analysis of Tibial Translation in Anterior Cruciate Ligament Injured Knees With and Without Bracing During Forward Lunge

    PubMed Central

    Jalali, Maryam; Farahmand, Farzam; Mousavi, Seyed Mohammad Ebrahim; Golestanha, Seyed Ali; Rezaeian, Tahmineh; Shirvani Broujeni, Shahram; Rahgozar, Mehdi; Esfandiarpour, Fateme

    2015-01-01

    Background: Despite several studies with different methods, the effect of functional knee braces on knee joint kinematics is not clear. Direct visualization of joint components through medical imaging modalities may provide the clinicians with more useful information. Objectives: In this study, for the first time in the literature, video fluoroscopy was used to investigate the effect of knee bracing on the sagittal plane kinematics of anterior cruciate ligament (ACL) injured patients. Patients and Methods: For twelve male unilateral ACL deficient subjects, the anterior tibial translation was measured during lunge exercise in non-braced and braced conditions. Fluoroscopic images were acquired from the subjects using a digital fluoroscopy system with a rate of 10 fps. The image of each frame was scaled using a calibration coin and analyzed in AutoCAD environment. The angle between the two lines, tangent to the posterior cortexes of the femoral and tibial shafts was measured as the flexion angle. For the fluoroscopic images associated with 0°, 15°, 30°, 45° and 60° knee flexion angles, the relative anterior-posterior configuration of the tibiofemoral joint was assessed by measuring the position of landmarks on the tibia and femur. Results: Results indicated that the overall anterior translations of the tibia during the eccentric (down) and concentric (up) phases of lunge exercise were 10.4 ± 1.7 mm and 9.0 ± 2.2 mm for non-braced, and 10.1 ± 3.4 mm and 7.4 ± 2.5 mm, for braced conditions, respectively. The difference of the tibial anterior-posterior translation behaviors of the braced and non-braced knees was not statistically significant. Conclusion: Fluoroscopic imaging provides an effective tool to measure the dynamic behavior of the knee joint in the sagittal plane and within the limitations of this study, the pure mechanical stabilizing effect of functional knee bracing is not sufficient to control the anterior tibial translation of the ACL deficient

  4. The effects of complex glyoxal based modifiers on properties of cement paste and hardened cement paste

    NASA Astrophysics Data System (ADS)

    Simakova, A.; Kudyakov, A.; Efremova, V.; Latypov, A.

    2017-01-01

    This paper presents the results of research on the effect of organic and glyoxal containing additives on the properties of cement paste and hardened cement paste. Complex modifying additives based on liquid glyoxal increasing the strength of the cement paste by 35-63% were developed. Physico-chemical investigations showed that hardened cement paste modified by polylactic acid with glyoxal has a homogeneous and fine-grained structure. Developed complex modifying additives containing glyoxal are approved for use in production technology of heavy cement concretes with advanced properties.

  5. Hypersensitivity in aseptic loosening of total hip replacements. The role of constituents of bone cement.

    PubMed

    Haddad, F S; Cobb, A G; Bentley, G; Levell, N J; Dowd, P M

    1996-07-01

    Aseptic loosening is seen in a significant proportion of cemented total hip replacements (THR). In a small subgroup of patients who suffer early loosening polyethylene debris is unlikely to be responsible. We recently reported one case of allergic contact dermatitis to N,N-dimethylparatoluidine (DMT), an accelerator used in bone cement. We have therefore investigated this using skin-patch tests to a variety of substances including metals, polyethylene and the separated individual components of Simplex cement. We studied 70 patients, 15 with aseptic loosening less than two years after THR, 25 with satisfactory long-term cemented fixation, five with infected loosening of cemented THRs and 25 awaiting hip arthroplasty. We found seven positive reactions to DMT, all of them in patients with the rapid onset of aseptic loosening. Allergy to DMT is recognized in the dental profession in respect of the 'denture sore mouth' syndrome, and could also be an occupational hazard since some industrial glues contain DMT. Our results suggest the need for awareness of possible previous dental or occupational exposure of the constituents of bone cement. We recommend the use of skin-patch testing in high-risk cases.

  6. Evaluation of colloidal silica suspension as efficient additive for improving physicochemical and in vitro biological properties of calcium sulfate-based nanocomposite bone cement.

    PubMed

    Borhan, Shokoufeh; Hesaraki, Saeed; Ahmadzadeh-Asl, Shaghayegh

    2010-12-01

    In the present study new calcium sulfate-based nanocomposite bone cement with improved physicochemical and biological properties was developed. The powder component of the cement consists of 60 wt% α-calcium sulfate hemihydrate and 40 wt% biomimetically synthesized apatite, while the liquid component consists of an aqueous colloidal silica suspension (20 wt%). In this study, the above mentioned powder phase was mixed with distilled water to prepare a calcium sulfate/nanoapatite composite without any additive. Structural properties, setting time, compressive strength, in vitro bioactivity and cellular properties of the cements were investigated by appropriate techniques. From X-ray diffractometer analysis, except gypsum and apatite, no further phases were found in both silica-containing and silica-free cements. The results showed that both setting time and compressive strength of the calcium sulfate/nanoapatite cement improved by using colloidal silica suspension as cement liquid. Meanwhile, the condensed phase produced from the polymerization process of colloidal silica filled the micropores of the microstructure and covered rodlike gypsum crystals and thus controlled cement disintegration in simulated body fluid. Additionally, formation of apatite layer was favored on the surfaces of the new cement while no apatite precipitation was observed for the cement prepared by distilled water. In this study, it was also revealed that the number of viable osteosarcoma cells cultured with extracts of both cements were comparable, while silica-containing cement increased alkaline phosphatase activity of the cells. These results suggest that the developed cement may be a suitable bone filling material after well passing of the corresponding in vivo tests.

  7. In vitro biocompatibility of a novel Fe2O3 based glass ionomer cement.

    PubMed

    Hurrell-Gillingham, K; Reaney, I M; Brook, I; Hatton, P V

    2006-09-01

    Since their invention in the late 1960s, glass ionomer cements (GICs) have been used extensively in dentistry but recently they have also been utilised in ear nose and throat (ENT) surgery. Unfortunately, Al3+, a component of conventional ionomer glasses, has been linked to poor bone mineralisation and neurotoxicity. The aim of the research was to modify a commercial ionomer glass composition by substituting Al2O3 with Fe2O3. Glasses with the following molar compositions were fabricated: 4.5SiO2*3M2O3*XP2O5*3CaO*2CaF2 (M = Al or Fe, X = 0-1.5). The glasses were characterised using X-ray fluorescence (XRF) and X-ray powder diffraction (XRD). Cements were prepared using a standard ratio of; 1 g of glass powder: 0.2 g of dried polyacrylic acid: 0.3 g of 10% tartaric acid solution. Cement formation was assessed using a Gilmore needle and in vitro biocompatibility was investigated for novel cement formulations. XRF revealed that the Fe2O3-based glasses had Al2O3 contamination from the crucibles and also had undergone substantial F- losses. XRD gave peaks that corresponded to magnetite Fe3O4 (JCPDS # 19-629) in all compositions. Apatite Ca5(PO4)3(OH,F) (JCPDS # 15-876) was identified in P2O5 containing glasses. It was possible to fabricate cements from all of the Fe2O3-based ionomer glasses. Good in vitro biocompatibility was observed for the Fe2O3-based cements. Ionomer glasses may be prepared by entirely replacing Al2O3 with Fe2O3. Cement setting times appeared to be related to P2O5 content. Fe2O3-based cements showed good in vitro biocompatibility.

  8. Preparation and in vitro evaluation of strontium-doped calcium silicate/gypsum bioactive bone cement.

    PubMed

    Wang, Juncheng; Zhang, Lei; Sun, Xiaoliang; Chen, Xiaoyi; Xie, Kailuo; Lin, Mian; Yang, Guojing; Xu, Sanzhong; Xia, Wei; Gou, Zhongru

    2014-08-01

    The combination of two or more bioactive components with different biodegradability could cooperatively improve the physicochemical and biological performances of the biomaterials. Here we explore the use of α-calcium sulfate hemihydrate (α-CSH) and calcium silicate with and without strontium doping (Sr-CSi, CSi) to fabricate new bioactive cements with appropriate biodegradability as bone implants. The cements were fabricated by adding different amounts (0-35 wt%) of Sr-CSi (or CSi) into the α-CSH-based pastes at a liquid-to-solid ratio of 0.4. The addition of Sr-CSi into α-CSH cements not only led to a pH rise in the immersion medium, but also changed the surface reactivity of cements, making them more bioactive and therefore promoting apatite mineralization in simulated body fluid (SBF). The impact of additives on long-term in vitro degradation was evaluated by soaking the cements in Tris buffer, SBF, and α-minimal essential medium (α-MEM) for a period of five weeks. An addition of 20% Sr-CSi to α-CSH cement retarded the weight loss of the samples to 36% (in Tris buffer), 43% (in SBF) and 54% (in α-MEM) as compared with the pure α-CSH cement. However, the addition of CSi resulted in a slightly faster degradation in comparison with Sr-CSi in these media. Finally, the in vitro cell-ion dissolution products interaction study using human fetal osteoblast cells demonstrated that the addition of Sr-CSi improved cell viability and proliferation. These results indicate that tailorable bioactivity and biodegradation behavior can be achieved in gypsum cement by adding Sr-CSi, and such biocements will be of benefit for enhancing bone defect repair.

  9. Unicompartmental knee prostheses: in vitro wear assessment of the menisci tibial insert after two different fixation methods

    NASA Astrophysics Data System (ADS)

    Affatato, S.; Spinelli, M.; Zavalloni, M.; Carmignato, S.; Lopomo, N.; Marcacci, M.; Viceconti, M.

    2008-10-01

    Knee osteoarthritis is a complex clinical scenario where many biological and mechanical factors influence the severity of articular degenerative changes. Minimally invasive knee prosthetic surgery, with only a compartment replacement (unicompartmental knee replacement), might be a good compromise between osteotomy and total knee prosthesis. The focus of this study was to develop and validate a protocol to assess the fixation method of the femoral components in mechanical simulation, for pre-clinical validation; the wear behaviour of two different fixation frames was quantified and compared. In particular, two different wear tests were conducted using the same knee simulator, the same load profiles and the same kinematics; two different fixation methods were applied to the femoral sleds (synthetic femur and metal block). Surface characterization on both articulating bearings was performed by a roughness measuring machine and coordinate measuring machine. The wear produced by the tibial inserts using the synthetic femur was considerably higher than the wear registered by the metal-block holder. Roughness measurements on femoral sleds showed a limited number of scratches with high Rt values for the metal-block set-up; the damaged surface broadened in the case of femoral condyles and tibial inserts mounted on composite bone, but lower Rt and linear penetration values were measured. The two holding frames showed different wear activities as a consequence of dissimilar dynamic performance. Further observations should be made in vivo to prove the actual importance of synthetic bone simulations and specific material behaviour.

  10. TECHNOLOGICAL CHANGES IN THE CEMENT MANUFACTURING INDUSTRY.

    ERIC Educational Resources Information Center

    WESSON, CARL E.

    THE PURPOSE OF THIS STUDY IS TO PRESENT A PRELIMINARY PICTURE OF OCCUPATIONAL CHANGES BROUGHT ABOUT IN THE MANUFACTURE OF CEMENT AS A RESULT OF INTRODUCING AUTOMATED EQUIPMENT. ONE AUTOMATED AND SEVERAL CONVENTIONAL TYPE CEMENT PLANTS WERE STUDIED. ANALYSIS OF DATA OBTAINED THROUGH RESEARCH AND DATA COLLECTED DURING THE STUDY REVEALED THAT…

  11. Basic Chemistry for the Cement Industry.

    ERIC Educational Resources Information Center

    Turner, Mason

    This combined student workbook and instructor's guide contains nine units for inplant classes on basic chemistry for employees in the cement industry. The nine units cover the following topics: chemical basics; measurement; history of cement; atoms; bonding and chemical formulas; solids, liquids, and gases; chemistry of Portland cement…

  12. Tires fuel oil field cement manufacturing

    SciTech Connect

    Caveny, B.; Ashford, D.; Garcia, J.G.

    1998-08-31

    In a new process, waste automobile tires added to the fuel mix of gas, coal, and coke help fire kilns to produce API-quality oil field cement. Capital Cement uses this process in its cement-manufacturing plant in San Antonio, in which it also produces construction cement. The tires provide a lower-cost fuel and boost the temperature at a critical stage in the kiln burn process. Also, steel-belted tires add iron content to the mix. According to lab results, tire-burned cement slurries will perform the same as conventionally burned cement slurries. Actual field applications have proven that cement produced by burning tiresmore » performs no different than conventionally produced slurries. Capital`s plant uses both dry and wet processes, with separate kilns running both processes at the same time. Cement clinker is partially fired by waste tires in both kiln processes. The tires represent 12% of the fuel consumed by the plant, a number that is expected to increase. Capital burns about 200 tires/hr, or about 1.6 million tires/year.« less

  13. Current Status of Cemented Carbide Technology

    DTIC Science & Technology

    1958-06-01

    OBJECT To determine the current status of cemented carbide technology, including fabrication, properties , and utilization, in...background, technological development, properties and applications of cemented carbides are presented in the body of this...report. Recommended test methods for the determination of some of the physical properties , i.e., hardness, transverse rupture

  14. A note on cement in asteroids

    NASA Astrophysics Data System (ADS)

    Bilalbegović, G.

    2016-09-01

    Cement mineral tobermorite was formed in hydrothermal experiments on alternation of calcium-aluminum-rich inclusions (CAIs) in carbonaceous chondrite meteorites. Unidentified bands at 14 μm were measured for CAIs and the matrix of the Allende meteorite sample, as well as for Hektor and Agamemnon asteroids. The presence of cement nanoparticles may explain the feature at 14 μm.

  15. Acrylic bone cement: current concept review.

    PubMed

    Magnan, B; Bondi, M; Maluta, T; Samaila, E; Schirru, L; Dall'Oca, C

    2013-08-01

    Acrylic bone cement has had for years an important role in orthopedic surgery. Polymethylmethacrylate (PMMA) has been extended from the ophthalmological and dental fields to orthopedics, as acrylic cement used for fixation of prosthetic implants, for remodeling osteoporotic, neoplastic and vertebral fractures repair. The PMMA bone cement is a good carrier for sustained antibiotic release in the site of infection. Joint prostheses chronic infection requires surgical removal of the implant, in order to eradicate the infection process. This can be performed in the same surgical time (one-stage procedure) or in two separate steps (two-stage procedure, which involves the use of an antibiotic-loaded cement spacer). The mechanical and functional characteristics of the spacers allow a good joint range of motion, weight-bearing in selected cases and a sustained release of antibiotic at the site of infection. The improvement of fixation devices in recent years was not accompanied by the improvement of elderly bone quality. Some studies have tested the use of PMMA bone cement or calcium phosphate as augmentation support of internal fixation of these fractures. Over the past 20 years, experimental study of acrylic biomaterials (bone cement, bioglass ceramic, cement additives, absorbable cement, antibiotic spacers) has been of particular importance, offering numerous models and projects.

  16. Comparison of tibial plateau angle changes after tibial plateau leveling osteotomy fixation with conventional or locking screw technology.

    PubMed

    Conkling, Amanda L; Fagin, Bennett; Daye, R Mark

    2010-06-01

    To compare the effects of locking and conventional screws on postoperative tibial plateau angle (TPA), osteotomy healing, and complication rate after tibial plateau leveling osteotomy (TPLO) in dogs treated for naturally occurring cranial cruciate ligament (CCL) rupture. Prospective clinical study. Dogs (n=118) with CCL rupture. Dogs (> or =20 kg) with unilateral CCL rupture and sufficient bone stock for TPLO and use of a 3.5-mm-broad or -narrow TPLO plate were sequentially allocated to have plate fixation with locking or conventional screws. Data analyzed included breed, age, sex, body weight, body condition score, limb operated, implants used, meniscal status, operative time, and days to recheck. Preoperative, immediate postoperative, and 8-week recheck mediolateral radiographs were reviewed, and TPA, complications, and healing status were evaluated. Stifles in the locking screw group had significantly less change in postoperative TPA than stifles in the conventional screw group. Locking screw fixation also had significantly higher grades of osteotomy healing, assessed on a mediolateral radiographic view. TPLO plates secured with locking screws are acceptable when compared with those secured with conventional screws; osteotomy healing is improved and TPA better conserved when using locking screws. Locking screw fixation serves to increase stabilization of TPA during TPLO healing and provides improved radiographic evidence of osteotomy healing.

  17. Higher division of the tibial nerve in the leg: gross anatomical study with clinical implications.

    PubMed

    Norzana, A G; Farihah, H S; Fairus, A; Teoh, S L; Nur, A K; Faizah, O; Das, S

    2013-01-01

    Tibial nerve is a branch of the sciatic nerve and it is the main nerve innervating the muscles of the back of the leg. The tibial nerve divides into medial and lateral plantar nerves. The level of division may be important for surgical purpose. The main aim of the present study was to observe the exact level of division of the tibial nerve and discuss its clinical implications. A total of 20 cadaveric limbs (irrespective of left or right side) were taken randomly. The posterior compartment of the thigh and leg was dissected to trace the tibial nerve and its branches. The specimens were subjected to measurements with respect to an arbitrary horizontal line passing through tip of medial malleolus and the calcaneum. All the specimens were photographed. In 5 cases (25%), the tibial nerve divided deep to the flexor retinaculum. In 15 cases (75%) cases, the tibial nerve divided at a distance of 3.5 cm - 6.5 cm (average 5 cm) above the medial malleolus. The tibial nerve and its divisions are important for performing successful nerve blocks and insertion of plates while treating fractures. Variations may account for the various discrepancies between the electromyographic tests and clinical tests.

  18. The relationship between posterior tibial slope and anterior cruciate ligament injury.

    PubMed

    Ristić, Vladimir; Maljanović, Mirsad C; Pericin, Branislav; Harhaji, Vladimir; Milankov, Miroslav

    2014-01-01

    The aim of this study was to identify an increased posterior tibial slope as a possible risk factor for anterior cruciate ligament injury. Sixty patients were divided into two groups (with and without anterior cruciate ligament rupture). The posterior tibial slope on the lateral and medial condyles was measured by sagittal magnetic resonance imaging slices by means of computerized method using circles to determine tibial axis. The patients with anterior cruciate ligament rupture had a statistically significantly (p = 0.06) greater posterior tibial slope on the lateral tibial condyle than the control group (6.68 degrees:5.64 degrees), and a greater slope on the medial condyle (5.49 degrees:4.67 degrees) in comparison to the patients with the intact anterior cruciate ligament. No significant difference in the average values of angles was observed between males and females with anterior cruciate ligament rupture, the average value being 6.23 degrees in men and 5.84 degrees in women on the lateral condyle, and 4.53 degrees in men and 4.53 degrees in women on the medial condyle. A statistically significant difference between the values of posterior tibial slope was observed between the groups with and without anterior cruciate ligament rupture, the sex having no affect on the value of the posterior tibial slope. The method of measuring angles should be unique.

  19. Foamed Cement Interactions with CO 2

    SciTech Connect

    Verba, Circe; Montross, Scott; Spaulding, Richard

    2017-01-23

    Geologic carbon storage (GCS) is a potentially viable strategy to reduce greenhouse emissions. Understanding the risks to engineered and geologic structures associated with GCS is an important first step towards developing practices for safe and effective storage. The widespread utilization of foamed cement in wells may mean that carbon dioxide (CO 2)/brine/foamed cement reactions may occur within these GCS sites. Characterizing the difference in alteration rates as well as the physical and mechanical impact of CO 2/brine/foamed cement is an important preliminary step to ensuring offshore and onshore GCS is a prudent anthropogenic CO 2 mitigation choice. In a typicalmore » oil and gas well, cement is placed in the annulus between the steel casing and formation rock for both zonal isolation and casing support. The cement must have sufficient strength to secure the casing in the hole and withstand the stress of drilling, perforating, and fracturing (e.g. API, 1997, 2010 Worldwide Cementing Practices). As such, measuring the mechanical and properties of cement is an important step in predicting cement behavior under applied downhole stresses (Nelson, 2006). Zonal isolation is the prevention of fluids migrating to different zones outside of the casing and is strongly impacted by the permeability of the wellbore cement (Nelson, 2006). Zonal isolation depends on both the mechanical behavior and permeability (a physical property) of the cement (Mueller and Eid, 2006; Nelson, 2006). Long-term integrity of cement depends on the mechanical properties of the cement sheath, such as Young’s Modulus (Griffith et al., 2004). The cement sheath’s ability to withstand the stresses from changes in pressure and temperature is predominantly determined by the mechanical properties, including Young’s modulus, Poisson’s ratio, and tensile strength. Any geochemical alteration may impact both the mechanical and physical properties of the cement, thus ultimately impacting the

  20. Principles and applications of cement slurries

    SciTech Connect

    Guillot, D.; Baret, J.F.

    1996-12-31

    The basic principles of oil well cementing are first described together with the main critical engineering constraints encountered during a primary cementing operation, that is, wellbore control, mud displacement, fluid loss control, and gas migration. Then cement slurry properties that are relevant to the process are reviewed and the procedures used to measure these properties are discussed. Particular attention is given to rheological measurements that call be affected by wall slip when losing coaxial cylinder or pipe flow viscometers. This is followed by an overview of the additives that are used to obtained the required cement slurry or set cement properties, like weighting agents/extenders, retarders, dispersants, fluid loss agents, and antisettling agents. Some typical mechanisms of action of these additives are briefly discussed. 30 refs., 23 figs., 2 tabs.

  1. Additives for cement compositions based on modified peat

    SciTech Connect

    Kopanitsa, Natalya, E-mail: kopanitsa@mail.ru; Sarkisov, Yurij, E-mail: sarkisov@tsuab.ru; Gorshkova, Aleksandra, E-mail: kasatkina.alexandra@gmail.com

    2016-01-15

    High quality competitive dry building mixes require modifying additives for various purposes to be included in their composition. There is insufficient amount of quality additives having stable properties for controlling the properties of cement compositions produced in Russia. Using of foreign modifying additives leads to significant increasing of the final cost of the product. The cost of imported modifiers in the composition of the dry building mixes can be up to 90% of the material cost, depending on the composition complexity. Thus, the problem of import substitution becomes relevant, especially in recent years, due to difficult economic situation. The articlemore » discusses the possibility of using local raw materials as a basis for obtaining dry building mixtures components. The properties of organo-mineral additives for cement compositions based on thermally modified peat raw materials are studied. Studies of the structure and composition of the additives are carried out by physicochemical research methods: electron microscopy and X-ray analysis. Results of experimental research showed that the peat additives contribute to improving of cement-sand mortar strength and hydrophysical properties.« less