Two Patients with Osteochondral Injury of the Weight-Bearing Portion of the Lateral Femoral Condyle Associated with Lateral Dislocation of the Patella

PubMed Central

Inoue, Hiroaki; Atsumi, Satoru; Ichimaru, Shohei; Fujiwara, Hiroyoshi; Kubo, Toshikazu

2014-01-01

Complications of patellar dislocation include osteochondral injury of the lateral femoral condyle and patella. Most cases of osteochondral injury occur in the anterior region, which is the non-weight-bearing portion of the lateral femoral condyle. We describe two patients with osteochondral injury of the weight-bearing surface of the lateral femoral condyle associated with lateral dislocation of the patella. The patients were 18- and 11-year-old females. Osteochondral injury occurred on the weight-bearing surface distal to the lateral femoral condyle. The presence of a free osteochondral fragment and osteochondral injury of the lateral femoral condyle was confirmed on MRI and reconstruction CT scan. Treatment consisted of osteochondral fragment fixation or microfracture, as well as patellar stabilization. Osteochondral injury was present in the weight-bearing portion of the lateral femoral condyle in both patients, suggesting that the injury was caused by friction between the patella and lateral femoral condyle when the patella was dislocated or reduced at about 90° flexion of the knee joint. These findings indicate that patellar dislocation may occur and osteochondral injury may extend to the weight-bearing portion of the femur even in deep flexion, when the patella is stabilized on the bones of the femoral groove. PMID:25506015

[Current status and expectations in the surgical treatment of recurrent lateral patellar dislocation].

PubMed

Zhao, Zhi-Dong; Li, Peng-Cui; Wei, Xiao-Chun

2017-11-25

Up to now, surgical treatment of recurrent lateral patellar dislocation mainly includes: medial patellofemoral ligament reconstruction, tibial tubercle osteotomy, trochleoplasty, lateral retinacular release, derotation osteotomy and so on . Clinical reports show that: the use of a single or combined with several methods have achieved ideal short to mid-term clinical outcomes. However, there is no consolidate criterion concerning the choices of different kinds of surgical ways for the treatment of individual recurrent lateral patellar dislocation. Meanwhile, with the wide use of MPFL reconstruction and other surgical options, there are more and more complications and failures that are worthy and necessary for us to pay attention to, even though its high success rate. The aim of this article is to make a systematic review of the application status of different surgical methods, collecting the positive results we have achieved, illuminating application keys of surgical techniques, guiding patient-specific therapy more precisely. Copyright© 2017 by the China Journal of Orthopaedics and Traumatology Press.

RANDOMIZED PROSPECTIVE STUDY ON TRAUMATIC PATELLAR DISLOCATION: CONSERVATIVE TREATMENT VERSUS RECONSTRUCTION OF THE MEDIAL PATELLOFEMORAL LIGAMENT USING THE PATELLAR TENDON, WITH A MINIMUM OF TWO YEARS OF FOLLOW-UP.

PubMed

Bitar, Alexandre Carneiro; D'Elia, Caio Oliveira; Demange, Marco Kawamura; Viegas, Alexandre Christo; Camanho, Gilberto Luis

2011-01-01

The aim of this study was to compare the surgical results from reconstruction of the medial patellofemoral ligament (MPFL) with non-operative treatment of primary patellar dislocation. Thirty-nine patients (41 knees) with patellar dislocation were randomized into two groups. One group was treated conservatively (immobilization and physiotherapy) and other was treated surgically with reconstruction of the MPFL, and the results were evaluated with a minimum follow-up of two years. The Kujala questionnaire was applied to assess pain and quality of life, and recurrences were evaluated. Pearson's chi-square test and Fisher's exact test were used in the statistical evaluation. The statistical analysis showed that the mean Kujala score was significantly lower in the conservative group (70.8), compared with the mean value in the surgical group (88.9), with p = 0.001. The surgical group presented a higher percentage of "good/excellent" Kujala score results (71.43%) than in the conservative group (25.0%), with p = 0.003. The conservative group presented a greater number of recurrences (35% of the cases), while in the surgical group there were no reports of recurrences and/or subluxation. Treatment with reconstruction of the medial patellofemoral ligament using the patellar tendon produced better results, based on the analysis of post-treatment recurrences and the better final results from the Kujala questionnaire after a minimum follow-up period of two years.

Lateral patellar retinaculum reconstruction for medial patellar instability following lateral retinacular release: a case report.

PubMed

Udagawa, Kazuhiko; Niki, Yasuo; Matsumoto, Hiroaki; Matsumoto, Hideo; Enomoto, Hiroyuki; Toyama, Yoshiaki; Suda, Yasunori

2014-01-01

Lateral retinacular release is still being performed in patients with recurrent patellar dislocation as an additional procedure with distal realignment or medial patellofemoral ligament (MPFL) reconstruction. However, consensus remains lacking regarding suitable indications for lateral retinacular release. A 20-year-old woman presented with patellar instability in both medial and lateral directions after undergoing lateral retinacular release with MPFL reconstruction. She displayed inherent systemic joint laxity meeting all seven Carter-Wilkinson criteria. Simultaneous MPFL revision and lateral retinaculum reconstruction successfully improved patellar instability in both directions. This case provides an example of iatrogenic medial patellar instability after failed lateral retinacular release. Copyright © 2013 Elsevier B.V. All rights reserved.

Clinical Outcomes After the Nonoperative Management of Lateral Patellar Dislocations: A Systematic Review

PubMed Central

Moiz, Munim; Smith, Nick; Smith, Toby O.; Chawla, Amit; Thompson, Peter; Metcalfe, Andrew

2018-01-01

Background: The first-line treatment for patellar dislocations is often nonoperative and consists of physical therapy and immobilization techniques, with various adjuncts employed. However, the outcomes of nonoperative therapy are poorly described, and there is a lack of quality evidence to define the optimal intervention. Purpose: To perform a comprehensive review of the literature and assess the quality of studies presenting patient outcomes from nonoperative interventions for patellar dislocations. Study Design: Systematic review; Level of evidence, 4. Methods: The MEDLINE, AMED, Embase, CINAHL, Cochrane Library, PEDro, and SPORTDiscus electronic databases were searched through July 2017 by 3 independent reviewers. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed. Study quality was assessed using the CONSORT (Consolidated Standards for Reporting Trials) criteria for randomized controlled trials and the Newcastle-Ottawa Scale for cohort studies and case series. Results: A total of 25 studies met our inclusion criteria, including 12 randomized controlled trials, 7 cohort studies, and 6 case series, consisting of 1066 patients. Studies were grouped according to 4 broad categories of nonoperative interventions based on immobilization, weightbearing status, quadriceps exercise type, and alternative therapies. The most commonly used outcome measure was the Kujala score, and the pooled redislocation rate was 31%. Conclusion: This systematic review found that patient-reported outcomes consistently improved after all methods of treatment but did not return to normal. Redislocation rates were high and close to the redislocation rates reported in natural history studies. There is a lack of quality evidence to advocate the use of any particular nonoperative technique for the treatment of patellar dislocations. PMID:29942814

Diagnosis and Characterization of Patellofemoral Instability: Review of Available Imaging Modalities.

PubMed

Haj-Mirzaian, Arya; Thawait, Gaurav K; Tanaka, Miho J; Demehri, Shadpour

2017-06-01

Patellofemoral instability (PI) is defined as single or multiple episodes of patellar dislocation. Imaging modalities are useful for characterization of patellar malalignment, maltracking, underlying morphologic abnormalities, and stabilizing soft-tissue injuries. Using these findings, orthopedic surgeons can decide when to operate, determine the best operation, and measure degree of correction postoperatively in PI patients. Also, these methods assist with PI diagnosis in some suspicious cases. Magnetic resonance imaging is the preferred method especially in the setting of acute dislocations. Multidetector computed tomography allows a more accurate assessment for malalignment such as patellar tilt and lateral subluxation and secondary osteoarthritis. Dynamic magnetic resonance imaging and 4-dimensional computed tomography have been introduced for better kinematic assessment of the patellofemoral maltracking during extension-flexion motions. In this review article, we will discuss the currently available evidence regarding both the conventional and the novel imaging modalities that can be used for diagnosis and characterization of PI.

Rare cause of knee pain after martial arts demonstration: a case report.

PubMed

Armstrong, Marc B; Thurber, Jalil

2013-04-01

Patellar dislocations are a commonly treated injury in the Emergency Department (ED), with a majority of cases involving lateral subluxation of the patella outside of the joint space. Intra-condylar dislocations of the patella are rare. Of the two types of axis rotation, vertical and horizontal, the vertical occurs five times less frequently. These injuries most often undergo open reduction or, at best, closed reduction under general anesthesia. To remind Emergency Physicians to consider this injury in any patient with severe knee pain and limited mobility, even with a history that is lacking significant trauma. We present a case of intra-condylar patellar dislocation with vertical axis rotation. This injury is no longer primarily attributed to the young and, barring fracture, closed reduction in the ED should be considered. Copyright © 2013 Elsevier Inc. All rights reserved.

[Clinical significance of Q-angle under different conditions in recurrent patellar dislocation].

PubMed

Wang, Zhijie; Chen, You; Li, Anping; Long, Yi

2014-01-01

To investigate the clinical significance of Q-angle measuring under different conditions in female recurrent patellar dislocation female patients. Between August 2012 and March 2013, 10 female patients (11 knees) with recurrent patellar dislocation were collected as trial group; 20 female patients (20 knees) with simple meniscus injury were collected as control group at the same time. Q-angle was measured in extension, 30 degrees flexion, 30 degrees flexion with manual correction, and surgical correction in the trial group, and only in extension and 30 degrees flexion in the control group. Then the difference value of Q-angle between extension and 30 degrees flexion (Q-angle in extension subtracts Q-angle in 30 flexion) were calculated. Independent sample t-test was used to analyze Q-angle degrees in extension, 30 degrees flexion, and the changed degrees of 2 groups. The Q-angle between manual correction and surgical correction of the trial group was analyzed by paired t-test. The Q-angle in extension, Q-angle in 30 degrees flexion, and difference value of Q-angle between extension and 30 degrees flexion were (17.2 +/- 3.6), (14.3 +/- 3.0), and (2.9 +/- 1.9) degrees in the trial group and were (15.2 +/- 3.4), (14.4 +/- 3.5), and (0.8 +/- 1.7) degrees in the control group. No significant difference was found in Q-angle of extension or Q-angle of 30 degrees flexion between 2 groups (P > 0.05), but the difference value of Q-angle between extension and 30 degrees flexion in the trial group was significantly larger than that in the control group (t = 3.253, P = 0.003). The Q-angle in 30 degrees flexion with manual correction and surgical correction in the trial group was (19.8 +/- 3.4) degrees and (18.9 +/- 3.8) degrees respectively, showing no significant difference (t = 2.193, P = 0.053). When a female patient's Q-angle in 30 degrees flexion knee changes obviously compared with Q-angle in extension position, recurrent patellar dislocation should be considered. For female patients with recurrent patellar dislocation, the preoperative Q-angle in 30 degrees flexion with manual correction should be measured, which can help increasing the accuracy of evaluation whether rearrangement should be performed.

Medial patellofemoral ligament reconstruction with a divergent patellar transverse 2-tunnel technique.

PubMed

Panni, Alfredo Schiavone; Alam, Mahbub; Cerciello, Simone; Vasso, Michele; Maffulli, Nicola

2011-12-01

The medial patellofemoral ligament (MPFL) is the primary passive restraint to lateral patellar dislocation and there is increasing awareness of its role in recurrent lateral patellar instability. This study was conducted to prospectively analyze the functional results of a modified MPFL reconstruction technique in recurrent patellar dislocation. Case series; Level of evidence, 4. Forty-eight patients (51 knees) with at least 3 episodes of lateral patellar dislocation who had been treated with a 6-month rehabilitation protocol were included in this study. All patients practiced sports regularly. Reconstruction was with a semitendinosus tendon using a divergent 2-tunnel technique. Outcome was evaluated with the Kujala, Larsen, modified Lysholm, and Fulkerson outcome scores. Patient satisfaction with range of motion, pain, and sporting activities was also assessed. Three patients were lost at the final follow-up, giving a follow-up rate of 94%. The mean follow-up was 33 months. There was no patella dislocation postoperatively. The mean Kujala score improved significantly (P < .01) from 56.7 ± 17.7 (2 × standard deviation) preoperatively to 86.8 ± 14.4 postoperatively. The mean Larsen score improved significantly (P < .01) from 12.4 ± 3.2 to 17.1 ± 2.7. The mean Fulkerson score improved significantly (P < .01) from 59.2 ± 21.8 to 90.1 ± 14. The mean modified Lysholm score improved significantly (P < .01) from 57.6 ± 19.6 to 88.1 ± 16.2. Sixty-four percent of patients returned to the same type of sport at the same level, 16% reduced the level or type of sport for reasons unrelated to the surgery, while 20% reduced the level of sport or changed it for reasons related to surgery. Eighty-seven percent were either satisfied or very satisfied with the pain relief achieved. The patellar tilt decreased significantly from a preoperative mean of 11.1° to 8.9° at the last follow-up (P = .02). The mean preoperative Insall-Salvati ratio of 1.1 decreased to 1.06, although the change was not significant (P = .1). The results of modified MPFL reconstructions are encouraging, with minimal risks of redislocation and an overall patient satisfaction rate of over 80%. These early and medium-term results are comparable with those of other MPFL reconstruction techniques reported in the literature.

Arthroscopic evaluation of patellofemoral congruence with rotation of the knee joint and electrical stimulation of the quadriceps.

PubMed

Suganuma, Jun; Mochizuki, Ryuta; Inoue, Yutaka; Kitamura, Kazuya; Honda, Akio

2014-02-01

The aim of this study was to investigate the pathoanatomic features of patellar instability by arthroscopically comparing patellofemoral congruence with rotation of the knee joint and/or electrical stimulation of the quadriceps (ESQ) between knees with and without patellar instability. We retrospectively examined 83 knee joints in 83 patients. The joints were classified into 2 groups: group 1 comprised those without a history of patellar dislocation and included 59 patients (25 male and 34 female patients), and group 2 comprised those with a history of patellar dislocation and included 24 patients (9 male and 15 female patients). Evaluation of patellofemoral congruence at 30° of flexion of the knee joint was conducted based on an axial radiograph and arthroscopic findings. The congruence angle was measured on the radiograph. The position of the patellar central ridge (PPCR) on the trochlear groove during arthroscopy was measured using still video frames of knee joints with rotational stress and/or ESQ. Statistical differences in the measurements between the 2 groups were assessed with the unpaired t test and the area under the receiver operating characteristic curve of each measurement. There were significant differences (P < .0001) between the 2 groups in the congruence angle on radiographs and PPCR in knee joints with rotational stress and/or ESQ on arthroscopy. External and internal rotation of the knee joint caused lateral and medial patellar shift, respectively, in both groups, but the shift was significantly larger in group 2. ESQ in addition to rotation caused further patellar shift in group 2 but reduced patellar shift in group 1. Measurement of PPCR with external rotation of the knee and ESQ was the only method to show an area under the receiver operating characteristic curve of 1. There were significant differences in the effects of rotation of the knee joint and/or ESQ on patellofemoral congruence at 30° of flexion of the knee joint on arthroscopy between knees with and without patellar instability. Level III, diagnostic study of nonconsecutive patients. Copyright © 2014 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Sonography on injury of the medial patellofemoral ligament after acute traumatic lateral patellar dislocation: Injury patterns and correlation analysis with injury of articular cartilage of the inferomedial patella.

PubMed

Zhang, Guang-Ying; Zheng, Lei; Shi, Hao; Qu, Su-Hui; Ding, Hong-Yu

2013-12-01

The purpose of this study was to investigate the accuracy of high-frequency ultrasonography in the diagnosis of injuries of medial patellofemoral ligaments (MPFLs), analyse the characteristics of MPFL injury and correlations between injury of the MPFL and articular cartilage of the inferomedial patella in patients with acute traumatic lateral patellar dislocation. High-frequency sonographic images of 49 patients with acute traumatic lateral patellar dislocations treated surgically were reviewed. The χ(2) tests were performed for statistical analysis. Twenty-eight cases of complete MPFL tear and 21 cases of partial MPFL tear were identified in operation, with 27 cases of MPFL tear located at their femoral attachment, 21 cases of tear at the patellar attachment and one case of midsubstance tear. The diagnostic accuracy of sonography regarding partial MPFL tear and complete MPFL tear was 89.8% and 89.8%. Among the patients with MPFL tear at the patellar attachment, eight and six cases were concomitant with chondral and osteochondral lesions in the inferomedial patella, respectively, in contrast to nine and six cases in patients with MPFL tear at the femoral attachment, respectively. There was no significant difference between the two locations described above regarding the prevalence rates of chondral or osteochondral lesions of the inferomedial patella (P=0.732, P=0.614). Among the patients with complete MPFL tear, 12 and 10 cases were concomitant with chondral and osteochondral lesions in the inferomedial patella, respectively, while six and two cases were concomitant with partial MPFL tear. There was no significant difference between the two types of injuries discussed above on the prevalence rates of chondral lesions of the inferomedial patella (P=0.305), but the prevalence rate of osteochondral lesions between the two types of injuries discussed above was statistically different (P=0.035). The MPFL is most easily injured at the femoral attachment, secondly at the patellar attachment. High-frequency ultrasonography is an accurate method in the diagnosis of an MPFL tear. There are neither significant differences on the prevalence rates of chondral or osteochondral lesions of the inferomedial patella between locations of MPFL injuries, nor significant difference on the prevalence rates of chondral lesions between MPFL injury types; but the complete MPFL tear is more often concomitant with inferomedial patellar osteochondral lesions than the partial MPFL tear. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Patellar instability : diagnosis and treatment].

PubMed

Ngo, Trieu Hoai Nam; Martin, Robin

2017-12-13

The aim of this paper is to present recent advances in surgical management of patellar instability. Several anatomical factors were reported to promote instability. We propose to classify them in two groups. Extra articular factors are valgus and torsion deformity. Articular factors include trochlea and patella dysplasia, tibial tubercle lateralization and medial patellofemoral ligament (MPFL) insufficiency. Acute patellar dislocations are treated conservatively, with exception for osteochondral and MPFL avulsion fractures that require acute reinsertion. Surgery is considered for recurrent instability. As we aim for a correction of all contributing elements, we prefer a two stages approach. Extra articular factors are treated first by osteotomy, followed by articular factors after 4-6 months. This allows separate rehabilitation protocols.

Quantitative stress radiography of the patella and evaluation of patellar laxity before and after lateral release for recurrent dislocation patella.

PubMed

Niimoto, Takuya; Deie, Masataka; Adachi, Nobuo; Usman, Muhammad Andry; Ochi, Mitsuo

2014-10-01

The aims of the present controlled clinical study were to (1) compare patella laxity determined in the outpatient clinic with that in anaesthetized patients and (2) evaluate patella laxity before and after lateral release. The study evaluated data on 33 knees from 33 patients (average age 19.7 years) between 2007 and 2011. All patients were diagnosed with recurrent dislocation of the patella. Patellar stability was evaluated in each patient thrice: patellas were first imaged in the outpatient clinic prior to surgery at 45° knee flexion with 20 N stress from the medial to lateral side and from the lateral to medial side; then, at the time of surgery, patella stress images were obtained in the same manner before and after the lateral release procedure. Radiological assessments were performed using the medial stress shift ratio (MSSR) and lateral stress shift ratio (LSSR). There were no significant differences in the LSSR and MSSR before surgery (outpatient data) and in anaesthetized patients before the lateral release procedure. Furthermore, there was no significant difference in MSSR at the time of surgery before and after the lateral release procedure. However, LSSR increased significantly after the lateral release procedure. The results of the present study suggest that quantitative patella stress radiography in the outpatient clinic is useful when it comes to investigating laxity of the patella, and that lateral release significantly increases lateral, but not medial, laxity in patients with recurrent patellar dislocation. IV.

Clinical Outcomes After Isolated Medial Patellofemoral Ligament Reconstruction for Patellar Instability Among Patients With Trochlear Dysplasia.

PubMed

Liu, Joseph N; Brady, Jacqueline M; Kalbian, Irene L; Strickland, Sabrina M; Ryan, Claire Berdelle; Nguyen, Joseph T; Shubin Stein, Beth E

2018-03-01

Medial patellofemoral ligament (MPFL) reconstruction has become one of the most common and widely used procedures to regain stability among patients with recurrent lateral patellar dislocation. While recent studies demonstrated low recurrence rates, improved patient-reported outcome measures, and a high rate of return to sports, limited literature explored its effectiveness as an isolated intervention in the context of trochlear dysplasia. To determine the efficacy of isolated MPFL reconstruction in treating patellar instability in the setting of trochlear dysplasia. Case series; Level of evidence, 4. This was a retrospective review of consecutive patients who underwent uni- or bilateral medial patellofemoral ligament reconstruction for patellofemoral instability with a minimum 2-year follow-up. No osteotomies were included. Pre- and postoperative assessment included ligamentous laxity, patellar crepitus, tilt, translation, apprehension, and radiographic features, including tibial tubercle-trochlear groove (TT-TG) distance, Dejour classification, and Caton-Deschamps index. A total of 121 MPFL reconstructions were included. Mean age at surgery was 23.8 years, and 4.4 dislocation events occurred before surgery. Mean follow-up was 44 months; 76% of patients were female. Mean preoperative TT-TG ratio was 13.5, and mean Caton-Deschamps ratio was 1.2; 92% of patients had Dejour B, C, or D trochlear dysplasia. Kujala score improved from 55.0 preoperatively to 90.0 ( P < .001). Almost all patients (94.5%) were able to return to sports at 1 year, with 74% returning to the same or higher level of play. Only 3 patients reported a postoperative dislocation or subluxation event. For patients without significantly elevated TT-TG distances or significant patella alta, isolated MPFL reconstruction provides a safe and effective treatment for patellofemoral instability, despite the presence of trochlear dysplasia. Most patients are able to return to sports by 1 year postoperatively at the same or higher level of play.

Combined distal femoral osteotomy (DFO) in genu valgum leads to reliable patellar stabilization and an improvement in knee function.

PubMed

Frings, Jannik; Krause, Matthias; Akoto, Ralph; Wohlmuth, Peter; Frosch, Karl-Heinz

2018-06-04

Valgus deformities of the lower extremity influence patellofemoral joint kinematics. However, studies examining the clinical outcome after treatment of patellar instability and maltracking due to valgus deformity are rare in recent literature. This study's purpose is to analyze the clinical results after combined distal femoral osteotomy (DFO) for treatment of patellar instability. From 2010 to 2016, 406 cases of patellofemoral instability and maltracking were treated. Twenty cases of recurring (≥ 2) patellar dislocations with genu valgum and unsuccessful conservative treatment were included in the study. A radiological analysis was performed, and anteroposterior (AP), lateral and long leg standing radiographs were analyzed, and the leg axis was pre- and postoperatively measured. At least 12 months postoperatively, the clinical leg axis, range of motion (ROM), apprehension sign, Zohlen sign, and J-sign were physically examined. Pain level and knee function were objectified on a visual analogue scale (VAS). The Lysholm, Kujala, and Tegner scores, re-dislocation rate, and patient satisfaction were also examined. 20 combined DFOs on 18 patients with a median age of 23 years (15-55 years) were performed. The preoperative mechanical leg axis was 6.5° ± 2.0° valgus, and the mean tibial tuberosity to trochlear groove (TT-TG) distance was 19.1 ± 4.8 mm. All patients reported multiple dislocations. Intraoperatively, 71% presented III°-IV° cartilage lesions, located retropatellarly in 87% and correlating negatively with the postoperative Lysholm score (r = - 0.462, p = 0.040). The leg axis was corrected by 7.1° ± 2.6°, and in 17 cases, the tibial tubercle was additionally medialized by 10 ± 3.1 mm. All patellae were re-stabilized with medial patellofemoral ligament reconstruction. After a median period of 16 (12-64) months, the pain level decreased from 8.0 ± 1.4 to 2.3 ± 2.1 (VAS p ≤ 0.001) and knee function improved from 40.1 ± 17.9 to 78.5 ± 16.6 (Kujala p ≤ 0.001), 36.1 ± 19.5 to 81.6 ± 11.7 (Lysholm p ≤ 0.001), and 2.0 (1-5) to 4.0 (3-6) (median Tegner p ≤ 0.001). No re-dislocation was observed. Combined DFO is a suitable treatment for patellar instability and maltracking due to genu valgum, as it leads to very low re-dislocation rates, a significant reduction of pain, and a significant increase of knee function with good-to-excellent results in the short-term follow-up. However, a high prevalence of substantial cartilage lesions is observed, causing postoperative limitations of knee function. IV, retrospective cohort study.

Lateralization of the Tibial Tubercle in Recurrent Patellar Dislocation: Verification Using Multiple Methods to Evaluate the Tibial Tubercle.

PubMed

Tensho, Keiji; Shimodaira, Hiroki; Akaoka, Yusuke; Koyama, Suguru; Hatanaka, Daisuke; Ikegami, Shota; Kato, Hiroyuki; Saito, Naoto

2018-05-02

The tibial tubercle deviation associated with recurrent patellar dislocation (RPD) has not been studied sufficiently. New methods of evaluation were used to verify the extent of tubercle deviation in a group with patellar dislocation compared with that in a control group, the frequency of patients who demonstrated a cutoff value indicating that tubercle transfer was warranted on the basis of the control group distribution, and the validity of these methods of evaluation for diagnosing RPD. Sixty-six patients with a history of patellar dislocation (single in 19 [SPD group] and recurrent in 47 [RPD group]) and 66 age and sex-matched controls were analyzed with the use of computed tomography (CT). The tibial tubercle-posterior cruciate ligament (TT-PCL) distance, TT-PCL ratio, and tibial tubercle lateralization (TTL) in the SPD and RPD groups were compared with those in the control group. Cutoff values to warrant 10 mm of transfer were based on either the minimum or -2SD (2 standard deviations below the mean) value in the control group, and the prevalences of patients in the RPD group with measurements above these cutoff values were calculated. The area under the curve (AUC) in receiver operating characteristic (ROC) curve analysis was used to assess the effectiveness of the measurements as predictors of RPD. The mean TT-PCL distance, TT-PCL ratio, and TTL were all significantly greater in the RPD group than in the control group. The numbers of patients in the RPD group who satisfied the cutoff criteria when they were based on the minimum TT-PCL distance, TT-PCL ratio, and TTL in the control group were 11 (23%), 7 (15%), and 6 (13%), respectively. When the cutoff values were based on the -2SD values in the control group, the numbers of patients were 8 (17%), 6 (13%), and 0, respectively. The AUC of the ROC curve for TT-PCL distance, TT-PCL ratio, and TTL was 0.66, 0.72, and 0.72, respectively. The extent of TTL in the RPD group was not substantial, and the percentages of patients for whom 10 mm of medial transfer was indicated were small. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Trochleoplasty as a Solitary Treatment for Recurrent Patellar Dislocation Results in Good Clinical Outcome in Adolescents.

PubMed

Camathias, Carlo; Studer, Katrin; Kiapour, Ata; Rutz, Erich; Vavken, Patrick

2016-11-01

The essential static patellar stabilizer is a normal-shaped trochlear groove. A dysplastic groove destabilizes the patella. Trochleoplasty approaches this underlying condition and reshapes the trochlea. However, studies have reported on trochleoplasty for revision cases or as accompanied by other interventions. The effect of trochleoplasty alone remains unexplained. To introduce trochleoplasty as a stand-alone treatment for recurrent patellar dislocation and to compare its pre- to postoperative functional and clinical variables. Case series; Level of evidence, 4. A trochleoplasty was performed in 50 knees (27 right) in 44 patients (30 females; mean ± SD age, 15.6 ± 2.0 years). The indication for surgery was recurrent patellar dislocation not responding to nonoperative treatment (>6 months), with types B through D dysplasia and closed or closing physes in adolescents aged 10 to 20 years. Assessment included J-sign and apprehension test, Kujala and Lysholm scores, patients' subjective assessment and activity level according to the International Knee Documentation Committee questionnaire, and patients' overall satisfaction. The Caton-Deschamps ratio and the lateral condyle index were measured. Pre- versus postoperative values were compared with a paired Wilcoxon signed-rank test. The minimum follow-up was 24 months (33 ± 10.6 months). The Kujala score improved from 71 preoperatively to 92 postoperatively (P < .001) and the Lysholm score from 71 to 95 (P < .001). Patients' subjective assessment improved at the final follow-up as compared with that preoperatively (P < .001). Most patients enhanced their activity (P < .001), and their overall satisfaction increased postoperatively (P < .001). Preoperatively, there was a positive J-sign in 45 knees and a positive apprehension test in 41 knees. Both markers disappeared postoperatively in 39 and 33 knees, respectively, leaving 6 knees with a positive J-sign and 8 knees with a positive apprehension test (P < .001). One patella redislocated postoperatively after 38 months. Four patients required a single arthroscopic debridement. In this study, trochleoplasty as a solitary treatment for recurrent patellofemoral dislocations in patients with trochlear dysplasia resulted in good clinical outcomes if severe torsional and axial malalignment was excluded. Kujala and Lysholm scores increased postoperatively, as well as subjective International Knee Documentation Committee assessment of outcomes, activity level, and overall satisfaction. © 2016 The Author(s).

The patellofemoral joint: from dysplasia to dislocation

PubMed Central

Zaffagnini, Stefano; Grassi, Alberto; Zocco, Gianluca; Rosa, Michele Attilo; Signorelli, Cecilia; Muccioli, Giulio Maria Marcheggiani

2017-01-01

Patellofemoral dysplasia is a major predisposing factor for instability of the patellofemoral joint. However, there is no consensus as to whether patellofemoral dysplasia is genetic in origin, caused by imbalanced forces producing maltracking and remodelling of the trochlea during infancy and growth, or due to other unknown and unexplored factors. The biomechanical effects of patellofemoral dysplasia on patellar stability and on surgical procedures have not been fully investigated. Also, different anatomical and demographic risk factors have been suggested, in an attempt to identify the recurrent dislocators. Therefore, a comprehensive evaluation of all the radiographic, MRI and CT parameters can help the clinician to assess patients with primary and recurrent patellar dislocation and guide management. Patellofemoral dysplasia still represents an extremely challenging condition to manage. Its controversial aetiology and its complex biomechanical behaviour continue to pose more questions than answers to the research community, which reflects the lack of universally accepted guidelines for the correct treatment. However, due to the complexity of this condition, an extremely personalised approach should be reserved for each patient, in considering and addressing the anatomical abnormalities responsible for the symptoms. Cite this article: EFORT Open Rev 2017;2. DOI: 10.1302/2058-5241.2.160081. Originally published online at www.efortopenreviews.org PMID:28630757

Correlation of 3D Shift and 3D Tilt of the Patella in Patients With Recurrent Dislocation of the Patella and Healthy Volunteers: An In Vivo Analysis Based on 3-Dimensional Computer Models.

PubMed

Yamada, Yuzo; Toritsuka, Yukiyoshi; Nakamura, Norimasa; Horibe, Shuji; Sugamoto, Kazuomi; Yoshikawa, Hideki; Shino, Konsei

2017-11-01

The concepts of lateral deviation and lateral inclination of the patella, characterized as shift and tilt, have been applied in combination to evaluate patellar malalignment in patients with patellar dislocation. It is not reasonable, however, to describe the 3-dimensional (3D) positional relation between the patella and the femur according to measurements made on 2-dimensional (2D) images. The current study sought to clarify the relation between lateral deviation and inclination of the patella in patients with recurrent dislocation of the patella (RDP) by redefining them via 3D computer models as 3D shift and 3D tilt. Descriptive laboratory study. Altogether, 60 knees from 56 patients with RDP and 15 knees from 10 healthy volunteers were evaluated. 3D shift and tilt of the patella were analyzed with 3D computer models created by magnetic resonance imaging scans obtained at 10° intervals of knee flexion (0°-50°). 3D shift was defined as the spatial distance between the patellar reference point and the midsagittal plane of the femur; it is expressed as a percentage of the interepicondylar width. 3D tilt was defined as the spatial angle between the patellar reference plane and the transepicondylar axis. Correlations between the 2 parameters were assessed with the Pearson correlation coefficient. The patients' mean Pearson correlation coefficient was 0.895 ± 0.186 (range, -0.073 to 0.997; median, 0.965). In all, 56 knees (93%) had coefficients >0.7 (strong correlation); 1 knee (2%), >0.4 (moderate correlation); 2 knees (3%), >0.2 (weak correlation); and 1 knee (2%), <0.2 (no correlation). The mean correlation coefficient of the healthy volunteers was 0.645 ± 0.448 (range, -0.445 to 0.982; median, 0.834). A statistically significant difference was found in the distribution of the correlation coefficients between the patients and the healthy volunteers ( P = .0034). When distribution of the correlation coefficients obtained by the 3D analyses was compared with that by the 2D (conventional) analyses, based on the bisect offset index and patellar tilt angle, the 3D analyses showed statistically higher correlations between the lateral deviation and inclination of the patella ( P < .01). 3D shift and 3D tilt of the patella were moderately or strongly correlated in 95% of patients with RDP at 0° to 50° of knee flexion. It is not always necessary to use both parameters when evaluating patellar alignment, at least for knees with RDP at 0° to 50° of flexion. Such a description may enable surgeons to describe patellar alignment more simply, leading to a better, easier understanding of the characteristics of each patient with RDP.

A combined procedure with Bereiter-type trochleoplasty leads to a stable patellofemoral joint at 5-year follow-up.

PubMed

Wind, Rutger J P; Heesterbeek, Petra J C; Wymenga, Ate B

2018-06-11

Trochlear dysplasia is a major risk factor predisposing to patellar instability and has been reported to occur in up to 85% of patients with recurrent patellar dislocation. Different operative techniques have been described to correct trochlear dysplasia, including the Bereiter technique, in which subchondral bone is removed and the cartilage can be compressed into a U-shaped groove. The hypothesis was that after a Bereiter-type trochleoplasty combined with medialisation of the tibial tubercle and MPFL reconstruction, patellar pain and instability decreased and anatomic reconstruction can be seen radiographically after 5-year follow-up. Between 2004 and 2011, a combined procedure including Bereiter-type trochleoplasty was performed on 21 consecutively included patients (22 knees) with objective patellar instability and severe trochlear dysplasia. Instability and pain were assessed preoperatively and 3, 6, 12, 24 and 60 months postoperatively with the visual analogue scale (VAS) for pain and instability, Kujala, International Knee Documentation Committee Subjective Knee Evaluation (IKDC SKE) and Short Form Health Survey (SF-36). Pre- and postoperatively, a true lateral radiograph was made to investigate the presence of the crossing sign and to measure the trochlear bump and trochlear depth, as well as a sunrise patella view to measure the sulcus angle. VAS pain and instability, Kujala and IKDC SKE improved significantly 5 years after trochleoplasty (p < 0.05). SF-36 showed no significant improvement. None of the patients reported patellar dislocations postoperatively. Sport activities remained limited. Postoperative radiographs showed no crossing sign. There was a significant increase in trochlear depth (p < 0.0001) and also a significant decrease in trochlear bump and sulcus angle (both p < 0.0001). A combined procedure consisting of Bereiter-type trochleoplasty, medialisation of the tibial tubercle and MPFL reconstruction in patients with objective patellar instability and severe trochlear dysplasia resulted in a clear decrease of pain and instability. Radiological assessment showed anatomical reconstruction. Nevertheless, residual symptoms remain and the possibility of future cartilage damage is uncertain. IV.

[Clinical study on patellar replacement in total knee arthroplasty].

PubMed

Bao, Liang; Gao, Zhihui; Shi, Xiaoqiang; Fang, Xiaomin; Jin, Qunhua

2013-01-01

To evaluate the influence of patellar replacement on total knee arthroplasty by comparing with non patellar replacement. Between September 2010 and November 2010, 63 patients (63 knees) with osteoarthritis who met the selection criteria and underwent total knee arthroplasty, were randomly divided into 2 groups: patellar replacement in 32 cases (replacement group), non patellar replacement in 31 cases (non patellar replacement group). There was no significant difference in gender, age, disease duration, osteoarthritis grading, the clinical and functional scores of American Knee Society Score (KSS), the patellar tilt angle, tibiofemoral angle, and patellar ligament ratio between 2 groups (P > 0.05), they were comparable. After 6 weeks, 3, 6, and 12 months of operation, clinical and imaging evaluation methods were used to assessment the effectiveness. Primary healing of incision was obtained in all patients of 2 groups. Deep venous thrombosis occurred in 6 cases of replacement group and in 8 cases of non patellar replacement group. All patients were followed up 12 months. The postoperative incidence of anterior knee pain in replacement group was significantly lower than that in non patellar replacement group (P < 0.05) at 3, 6, and 12 months after operation. No significant difference was found in the postoperative KSS clinical score between 2 groups at each time point (P > 0.05). The joint function score of the replacement group was significantly higher than that of the non patellar replacement group at the other time point (P < 0.05) except the score at 6 weeks and 3 months. Significant difference was found in the patella score between 2 groups at 12 months (P < 0.05), but no significant difference at the other time points (P > 0.05). X-ray film showed no patellar fracture and dislocation, or loosening and breakage of internal fixation. At 12 months after operation, the tibiofemoral angle, the patellar ligament ratio, and the patellar tilt angle showed no significant difference between 2 groups (P > 0.05). Patella replacement can improve knee function score and the patella score, and reduce the incidence of postoperative anterior knee pain.

The Anatomy of the Medial Patellofemoral Ligament.

PubMed

Trinh, Thai Q; Ferrel, Jason R; Bentley, Jared C; Steensen, Robert N

2017-07-01

Recurrent patellar dislocation is observed in many patients treated nonoperatively following primary dislocation. Injury to the medial patellofemoral ligament (MPFL) is reported in the majority of patients following dislocation. There is an increased interest in repair or reconstruction of the MPFL for patients experiencing recurrent instability. The femoral attachment of the MPFL is critical in determining graft behavior following reconstruction. The femoral attachment can be determined by referencing local anatomy, fluoroscopic imaging or on the basis of desired graft-length changes. This article reviews the anatomy of the MPFL, with a focus on its femoral insertion site as it pertains to anatomic, isometric, and anisometric reconstruction. [Orthopedics. 2017; 40(4):e583-e588.]. Copyright 2017, SLACK Incorporated.

Revision Surgery in Permanent Patellar Dislocation in DiGeorge Syndrome

PubMed Central

Berruto, Massimo; Parente, Andrea; Ferrua, Paolo; Pasqualotto, Stefano; Uboldi, Francesco; Usellini, Eva

2015-01-01

A 29-year-old patient, suffering from DiGeorge syndrome, came to our attention with a history of persistent pain and patellar instability in the left knee after failure of arthroscopic lateral release and Elmslie-Trillat procedure. The patient was unable to walk without crutches and severely limited in daily living activities. Because of arthritic changes of the patellofemoral joint and the failure of previous surgeries it was decided to perform only an open lateral release and medial patellofemoral ligament (MPFL) reconstruction using a biosynthetic ligament in order to obtain patellofemoral stability. At one year post-op range of motion (ROM) was 0–120 with a firm end point at medial patellar mobilization; patella was stable throughout the entire ROM. All the scores improved and she could be able to perform daily activity without sensation of instability. Bilateral patellar subluxation and systemic hyperlaxity are characteristics of syndromic patients and according to literature can be also present in DiGeorge syndrome. MPFL reconstruction with lateral release was demonstrated to be the correct solution in the treatment of patellar instability in this complex case. The choice of an artificial ligament to reconstruct the MPFL was useful in this specific patient with important tissue laxity due to her congenital syndrome. PMID:26783479

Management of comminuted patellar fracture with non-absorbable suture cerclage and Nitinol patellar concentrator.

PubMed

Lue, Tan Hong; Feng, Liu Wei; Jun, Wang Ming; Yin, Li Wu

2014-12-01

To evaluate the effectiveness and safety of a fixation technique for comminuted patellar fracture using non-absorbable suture cerclage and nickel-titanium patellar concentrator (Ni-Ti PC). Twenty-nine consecutive patients with displaced comminuted patellar fractures accepted internal fixation procedure using Ni-Ti PC augmented with different types of non-absorbable suture cerclage. During follow-up, the clinical grading scales of Böstman, including range of movement, pain, work, atrophy, assistance in walking, effusion, giving way, and stair-climbing, were used to evaluate the clinical results. Complications including implant loosening, fragment displacement, bone nonunion, infection, breakage of the implants, painful hardware, and post-traumatic osteoarthritis were also assessed. Patients were followed up for a mean period of 27 months. The bone union radiographically occurred approximately 2.5 months without implant loosening and fragment displacement. According to Böstman method, satisfactory results were obtained, and the mean score at final follow-up was 28 (range 20–30) points. Twenty-two patients with excellent results had mean score of 29.8 ± 0.5 (range 28–30) and seven patients with good results had mean score of 22.7 ± 3.14 (range 20–27). No postoperative complications, such as infection, dislocation, breakage of the implants, painful hardware, and post-traumatic osteoarthritis, were observed. Ni-Ti PC fixation with non-absorbable suture cerclage is a feasible approach for comminuted patellar fractures. Firm fixation with this technique resulted in satisfactory outcomes without obvious complications.

Does the Utilization of Allograft Tissue in Medial Patellofemoral Ligament Reconstruction in Pediatric and Adolescent Patients Restore Patellar Stability?

PubMed

Hohn, Eric; Pandya, Nirav K

2017-06-01

Medial patellofemoral ligament (MPFL) reconstruction is one of several surgical procedures used to treat patellofemoral instability. Use of allograft tissue can preserve autogenous tissue and may be preferable in patients with connective tissue disorders or ligamentous laxity. Although there are successful reports in adults, it is unclear if the use of allograft tissue in MPFL reconstruction can restore patellofemoral stability in children and adolescents. (1) Does allograft tissue in MPFL reconstruction in pediatric and adolescent patients restore patellar stability? (2) What complications were associated with allograft MPFL reconstructions in children and adolescents? Between June 2012 and August 2015, one surgeon (NKP) performed 26 MPFL reconstructions in 23 patients with gracilis allograft for traumatic patellar instability. Of those, 25 (96%) were available for followup more than 1 year later (mean, 24 months; range, 12-44 months). During this time, the surgeon suggested reconstruction to patients who had recurrent dislocation or subluxation after 6 weeks of bracing, physical therapy, and activity modification if they were noted to have a torn or attenuated MPFL on MRI. During that period, this was the only surgical technique the surgeon used to treat traumatic patellar instability. Patients undergoing concurrent bony procedures were ineligible for inclusion. The mean age of the patients in the series was 16.0 (± 2) years. Age, sex, skeletal maturity, presence of trochlear dysplasia, and additional arthroscopic procedures at the time of reconstruction were collected. Postoperative notes and imaging were reviewed for presence of complications defined as recurrent dislocation, recurrent subluxations, fractures, infection, or arthrofibrosis. These complications were identified by chart review by the senior surgeon (NKP) and study personnel (EH) not involved in clinical care of the patients or by patient-reported complications. Recurrent subluxation or dislocation was patient-reported at the time of the clinic visit or followup phone/email contact. Fractures were defined as any cortical disruption in the femur or patella that required treatment (change in postoperative protocol), infection requiring treatment (antibiotics and/or return to the operating room), or arthrofibrosis (stiffness that necessitated a change in the postoperative protocol or manipulation under anesthesia). Ninety-two percent (23 of 25) of patients reported no further instability episodes after MPFL reconstruction. Sixteen percent (four of 25) of patients had complications: two repeat episodes of patellar instability, one patella fracture, and one symptomatic hardware requiring interference screw removal. No patients developed arthrofibrosis or infection. In this small case series, we found that MPFL reconstruction using allograft tissue in children and adolescents resulted in a low risk of recurrent instability, perhaps comparable to what has been published by others who have used autograft tissue. Longer followup is needed, because in some orthopaedic applications, allograft ligaments have been observed to attenuate over time. Future studies might compare these techniques using patient-reported outcomes scores as well as use a control group of patients with autograft tissue. Level IV, therapeutic study.

Axial linear patellar displacement: a new measurement of patellofemoral congruence.

PubMed

Urch, Scott E; Tritle, Benjamin A; Shelbourne, K Donald; Gray, Tinker

2009-05-01

The tools for measuring the congruence angle with digital radiography software can be difficult to use; therefore, the authors sought to develop a new, easy, and reliable method for measuring patellofemoral congruence. The abstract goes here and covers two columns. The abstract goes The linear displacement measurement will correlate well with the congruence angle measurement. here and covers two columns. Cohort study (diagnosis); Level of evidence, 2. On Merchant view radiographs obtained digitally, the authors measured the congruence angle and a new linear displacement measurement on preoperative and postoperative radiographs of 31 patients who suffered unilateral patellar dislocations and 100 uninjured subjects. The linear displacement measurement was obtained by drawing a reference line across the medial and lateral trochlear facets. Perpendicular lines were drawn from the depth of the sulcus through the reference line and from the apex of the posterior tip of the patella through the reference line. The distance between the perpendicular lines was the linear displacement measurement. The measurements were obtained twice at different sittings. The observer was blinded as to the previous measurements to establish reliability. Measurements were compared to determine whether the linear displacement measurement correlated with congruence angle. Intraobserver reliability was above r(2) = .90 for all measurements. In patients with patellar dislocations, the mean congruence angle preoperatively was 33.5 degrees , compared with 12.1 mm for linear displacement (r(2) = .92). The mean congruence angle postoperatively was 11.2 degrees, compared with 4.0 mm for linear displacement (r(2) = .89). For normal subjects, the mean congruence angle was -3 degrees and the mean linear displacement was 0.2 mm. The linear displacement measurement was found to correlate with congruence angle measurements and may be an easy and useful tool for clinicians to evaluate patellofemoral congruence objectively.

Bilateral recurrent discloation of the patella associated with below knee amputation: A case report

PubMed Central

Batra, Sumit; Kumar, Ratnesh; Lenka, Prasanna

2005-01-01

Background Recurrent dislocation of the patella in patients with below knee amputation is a known entity. Abnormally high-riding patella (patella alta) and medial patellofemoral ligament insufficiency in these patients predisposes them to patellar instability. The established treatment of this problem is surgical realignment. Case presentation A 25 year old male patient with bilateral below knee amputation presented with bilateral recurrent dislocation of the patella while walking on knees on uneven ground. Clinical and radiographic studies showed patella alta. A simple shoe modification was used to treat this patient. Conclusions A simple shoe modification can be used to treat such a condition which is otherwise treated surgically. PMID:15717922

Recession wedge trochleoplasty as an additional procedure in the surgical treatment of patellar instability with major trochlear dysplasia: early results.

PubMed

Thaunat, M; Bessiere, C; Pujol, N; Boisrenoult, P; Beaufils, P

2011-12-01

The importance of a dysplastic trochlea as a component of patellar instability has long been recognized. An original trochleoplasty technique consisting in retro-trochlear recession wedge osteotomy was described by Goutallier et al. The aim is not to fashion a groove but to reduce the bump without modifying patellofemoral congruence. This retrospective study reports the operative technique and short-term outcomes of a consecutive case series of 17 patients (19 knees) who underwent recession wedge trochleoplasty for patellofemoral instability associated with severe trochlear dysplasia. Other contributing factors of patellar instability were also corrected as part of the surgical procedure: tibial tuberosity transfer (n=18), MPFL reconstruction (n=8). Minimum follow-up was 12 months (mean, 34 months; range, 12 to 71 months). The trochlear prominence was reduced from a mean 4.8mm (range, 0 to 8mm) to -0.8mm (range, -8 to 6mm). Patellar tilt was reduced from a mean 14° (range, 6° to 26°) to 6° (range, -1° to 24°). Two cases showed recurrent patellofemoral instability. Mean Kujala, KOOS and IKDC score were respectively 80 (± 17), 70 (± 18) and 67 (± 17) at last follow-up. Three patients required further operations, apart from removal of metal screws: arthroscopic arthrolysis for stiffness (n=1), revision for tibial tuberosity non-union (n=1), and supratrochlear exostosectomy (n=1). Recession wedge trochleoplasty is a feasible additional procedure addressing bony trochlear abnormality in the surgical treatment of patellar instability. Our attitude is to perform it never in isolation but associated to realignment of the extensor apparatus according to the à la carte surgery concept. It seems to be effective in preventing future patellar dislocation and reducing anterior knee pain in case of painful patellofemoral instability with a major dysplastic trochlea, or in revision cases when other realignment procedures have failed. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Patellar Instability Management: A Survey of the International Patellofemoral Study Group.

PubMed

Liu, Joseph N; Steinhaus, Michael E; Kalbian, Irene L; Post, William R; Green, Daniel W; Strickland, Sabrina M; Shubin Stein, Beth E

2017-10-01

Although patellofemoral instability is among the most prevalent knee disorders, the management of patients with this condition is complex and remains variable, given the lack of long-term, high-level clinical outcome studies to compare various operative and nonoperative modalities. To discover a consensus within treatment controversies in patellofemoral instability among experienced knee surgeons with a specific interest in the patellofemoral joint. Expert opinion; Level of evidence, 5. A 3-step modified Delphi technique was used to establish a consensus. A 34-question, case-based online survey regarding patellofemoral instability was distributed to all active members of the International Patellofemoral Study Group. Consensus statements were generated if at least 66% of the respondents agreed and then redistributed to the same panel. Modifications to the consensus statements were made based on the iterative feedback process until no discordance was encountered in the third stage. Eight consensus statements were achieved. Nonoperative management is the current standard of care for a first-time dislocation in the absence of an osteochondral fragment or loose body requiring excision (100% agreement). In patients with a first-time dislocation with an operative osteochondral fracture requiring excision or repair, patellar instability should be addressed concurrently (89% agreement). Recurrent instability should be treated surgically, with most surgeons favoring medial reconstruction (77%-86% agreement). While there is general agreement that bony procedures should be performed to correct underlying bony deformities, there is no consensus regarding the most appropriate type of procedure performed. Lateral release should not be performed in isolation for the treatment of patellar instability (89% agreement). Despite the consensus generated in this study, our current understanding remains limited by a lack of high-level evidence as well as the numerous complex variables influencing treatment decision making. High-quality, multicenter randomized controlled trials, particularly those directly comparing specific surgical treatment methods while controlling for underlying risk factors, are needed to address these areas of uncertainty.

Neglected bilateral congenital dislocation of the patella.

PubMed

Tokgöz, Mehmet Ali; Çavuşoğlu, Ali Turgay; Ayanoğlu, Tacettin; Elma, Tarık; Vural, Abdurrahman

2017-08-01

Congenital dislocation of the patella is a disorder that presents with dysfunction in extensor mechanism. Although congenital dislocation of the patella mostly occurs in children with genetic disorders, it may also occur in totally healthy children, despite rarely. In this article, we report a 16-year-old male patient who referred to our clinic with complaints of gait disturbance, frequent falls, and muscular weakness in lower extremity. The patient had no complaints during walking, but had difficulty in running and walking up and down the stairs. It was observed that the range of motion of the knee joint was completely painless and the quadriceps muscle strength was evaluated as 3/5. An evaluation of computed tomography and magnetic resonance imaging results showed that the patella was dislocated. It became clear with magnetic resonance imaging that extensor mechanism was continuous but patellar tendon was not attached to its anatomical position. Surgical treatment was not planned because the patient did not describe any pain complaint and there was no limitation of joint movement, he could walk without support and without device and also refused to be operated. The choice of treatment should be based on the patient's preference, and pain and functional status.

Medial Patellofemoral Ligament Reconstruction Procedure Using a Suspensory Femoral Fixation System

PubMed Central

Nakagawa, Shuji; Arai, Yuji; Kan, Hiroyuki; Ueshima, Keiichiro; Ikoma, Kazuya; Terauchi, Ryu; Kubo, Toshikazu

2013-01-01

Recurrent patellar dislocation has recently been treated with anatomic medial patellofemoral ligament (MPFL) reconstruction using a semitendinosus muscle tendon. Although it is necessary to add tension to fix the tendon graft without loading excess stress on the patellofemoral joint, adjustment of the tension can be difficult. To resolve this problem, we developed an MPFL reconstruction procedure using the ToggleLoc Fixation Device (Biomet, Warsaw, IN), in which the semitendinosus muscle tendon is folded and used as a double-bundle tendon graft and 2 bone tunnels and 1 bone tunnel are made on the patellar and femoral sides, respectively. The patellar side of the tendon graft is fixed with an EndoButton (Smith & Nephew, London, England), and the femoral side is fixed with the ToggleLoc. Stepless adjustment of tension of the tendon graft is possible by reducing the size of the loop of the ToggleLoc hung onto the tendon graft. It may be useful to position the patella in the center of the femoral sulcus by confirming the patellofemoral joint fitting. Stability can be confirmed by loading lateral stress on the patella in the extended knee joint. This procedure is less invasive because opening of the lateral side of the femur is not necessary, and it may be useful for MPFL reconstruction. PMID:24892014

Clinical and radiological outcomes after a quasi-anatomical reconstruction of medial patellofemoral ligament with gracilis tendon autograft.

PubMed

Monllau, Joan C; Masferrer-Pino, Àngel; Ginovart, Gerard; Pérez-Prieto, Daniel; Gelber, Pablo E; Sanchis-Alfonso, Vicente

2017-08-01

To analyse the clinical and radiological outcomes of a quasi-anatomical reconstruction of the medial patellofemoral ligament (MPFL) with a gracilis tendon autograft. Patients with objective recurrent patellar instability that were operated on from 2006 to 2012 were included. A quasi-anatomical surgical technique was performed using a gracilis tendon autograft. It was anatomically attached at the patella, and the adductor magnus tendon was also used as a pulley for femoral fixation (non-anatomical reconstruction). The IKDC, Kujala and Lysholm scores as well as Tegner and VAS for pain were collected preoperatively and at final follow-up. Radiographic measurements of patellar position tilt and signs of osteoarthritis (OA) as well as trochlear dysplasia were also recorded. Thirty-six patients were included. The mean age at surgery was 25.6 years. After a minimum 27 months of follow-up, all functional scores significantly improved (p < 0.001) with respect to the preoperative values. The VAS dropped from 6 (SD 2.48) to 2 (SD 1.58). No recurrence of dislocation was observed in this series. The apprehension sign was still apparent in one patient. The CT scan evaluation showed a significant decrease in patellar tilt (p < 0.001). On the Crosby and Insall grading scale, there were no changes in the radiological signs of OA. This specific MPFL reconstruction gives good clinical results and corrects patellar tilt. It did not affect the patellofemoral surfaces at the short term, as shown by the absence of radiological signs of OA in the CT scan. The procedure has been shown to be safe and suitable for the treatment of chronic patellar instability, including in adolescents with open physis. A new effective, inexpensive and easy-to-perform technique is described to reconstruct MPFL in the daily clinical practice. Therapeutic case series, Level IV.

Adolescent patellar instability: current concepts review.

PubMed

Clark, D; Metcalfe, A; Wogan, C; Mandalia, V; Eldridge, J

2017-02-01

Patellar instability most frequently presents during adolescence. Congenital and infantile dislocation of the patella is a distinct entity from adolescent instability and measurable abnormalities may be present at birth. In the normal patellofemoral joint an increase in quadriceps angle and patellar height are matched by an increase in trochlear depth as the joint matures. Adolescent instability may herald a lifelong condition leading to chronic disability and arthritis. Restoring normal anatomy by trochleoplasty, tibial tubercle transfer or medial patellofemoral ligament (MPFL) reconstruction in the young adult prevents further instability. Although these techniques are proven in the young adult, they may cause growth arrest and deformity where the physis is open. A vigorous non-operative strategy may permit delay of surgery until growth is complete. Where non-operative treatment has failed a modified MPFL reconstruction may be performed to maintain stability until physeal closure permits anatomical reconstruction. If significant growth remains an extraosseous reconstruction of the MPFL may impart the lowest risk to the physis. If minor growth remains image intensifier guided placement of femoral intraosseous fixation may impart a small, but acceptable, risk to the physis. This paper presents and discusses the literature relating to adolescent instability and provides a framework for management of these patients. Cite this article: Bone Joint J 2017;99-B:159-70. ©2017 The British Editorial Society of Bone & Joint Surgery.

Return to sport after patellar dislocation or following surgery for patellofemoral instability.

PubMed

Ménétrey, Jacques; Putman, Sophie; Gard, Suzanne

2014-10-01

Patellofemoral instability may occur in a young population as a result of injury during sporting activities. This review focuses on return to sport after one episode of dislocation treated no operatively and as well after surgery for chronic patellofemoral instability. With or without surgery, only two-thirds of patients return to sports at the same level as prior to injury. A high-quality rehabilitation programme using specific exercises is the key for a safe return to sporting activities. To achieve this goal, recovery of muscle strength and dynamic stability of the lower limbs is crucial. The focus should be directed to strengthen the quadriceps muscle and pelvic stabilizers, as well as lateral trunk muscle training. Patient education and regularly performed home exercises are other key factors that can lead to a successful return to sports. The criteria for a safe return to sports include the absence of pain, no effusion, a complete range of motion, almost symmetrical strength, and excellent dynamic stability. Level of evidence IV.

Q-vector measurements: physical examination versus magnetic resonance imaging measurements and their relationship with tibial tubercle-trochlear groove distance.

PubMed

Graf, Kristin H; Tompkins, Marc A; Agel, Julie; Arendt, Elizabeth A

2018-03-01

An increased lateral quadriceps vector has been associated with lateral patellar dislocation. Surgical correction of this increased vector through tibial tubercle medialization is often recommended when the quadriceps vector is "excessive". This can be evaluated by physical examination measurements of Q-angle and/or tubercle sulcus angle (TSA), as well as the magnetic resonance imaging (MRI) measurement of tibial tubercle-trochlear groove (TT-TG) distance. This study examined the relationship between three objective measurements of lateral quadriceps vector (TT-TG, Q-angle, TSA). A secondary goal was to relate lateral patellar tilt to these measurements. Consecutive patients undergoing patellofemoral stabilization surgery from 9/2010 to 6/2011 were included. The Q-angle and TSA were measured on intra-operative physical examination. The TT-TG and patellar tilt were measured on MRI. TSA, Q-angle, and patellar tilt were compared to TT-TG using Pearson correlation coefficient. The study cohort included 49 patients, ages 12-37 (mean 23.2); 62% female. The Pearson correlation coefficients showed (+) significance (p < 0.01) between the TT-TG and both TSA and Q-angle. Tilt and TT-TG were (+) non-significantly correlated. Despite positive correlations of each measurement with TT-TG, there is not uniform intra-patient correlation. In other words, if TT-TG is elevated for a patient, it does not guarantee that all other measurements, including tilt, are elevated in that individual patient. The TT-TG distance has significant positive correlation with the measurements of TSA and Q-angle in patients undergoing surgery for patellofemoral instability. The clinical relevance is that the variability within individual patients demonstrates the need for considering both TSA and TT-TG before and during surgical intervention to avoid overcorrection with a medial tibial tubercle osteotomy. Diagnostic study, Level III.

Analysis of failed surgery for patellar instability in children with open growth plates.

PubMed

Nelitz, Manfred; Theile, Michael; Dornacher, Daniel; Wölfle, Julia; Reichel, Heiko; Lippacher, Sabine

2012-05-01

Many surgical procedures have been proposed to treat recurrent patellar dislocation in children. In recent years, a more tailored approach considering the underlying pathology has been advocated. The aim of the study was to analyze a group of patients with recurrent patellofemoral instability after unsuccessful operative stabilization (Roux-Goldthwait procedure, lateral release, medial reefing or in combination) in childhood and adolescence. A total of 37 children and adolescents with recurrent patellofemoral instability despite previous surgery were analyzed retrospectively. Radiographic examination included AP and lateral views to assess patella alta and limb alignment. MRI was performed to evaluate trochlear dysplasia and tibial tubercle-trochlear groove (TTTG) distance. As a control group, 23 age- and sex-matched adolescents that were treated with a favorable outcome after medial reefing alone or combined with a Roux-Goldthwait procedure were analyzed. Severe trochlear dysplasia (type B-D according to Dejour) as detected on MRI scans was found significantly more often in the study group (89%) than in the control group (21%). No statistical difference of patellar height ratio (Insall-Salvati index) and TTTG distance between the two groups could be found. Of the measured parameters, only the incidence of trochlear dysplasia was increased. Trochlear dysplasia therefore seems to be a major risk factor for failure of operative stabilization of recurrent patellofemoral instability in children and adolescents. The results in children are in consensus with the literature in adults that a more tailored operative therapy including reconstruction of the MPFL and trochleaplasty has to be considered. Retrospective study, Level III.

A mini-invasive adductor magnus tendon transfer technique for medial patellofemoral ligament reconstruction: a technical note.

PubMed

Sillanpää, Petri J; Mäenpää, Heikki M; Mattila, Ville M; Visuri, Tuomo; Pihlajamäki, Harri

2009-05-01

Patellar dislocations are associated with injuries to the medial patellofemoral ligament (MPFL). Several techniques for MPFL reconstruction have been recently published with some disadvantages involved, including large skin incisions and donor site morbidity. Arthroscopic stabilizing techniques carry the potential of inadequate restoration of MPFL function. We present a minimally invasive technique for MPFL reconstruction using adductor magnus tendon autograft. This technique is easily performed, safe, and provides a stabilizing effect equal to current MPFL reconstructions. Skin incision of only 3-4 cm is located at the level of the proximal half of the patella. After identifying the distal insertion of the adductor magnus tendon, a tendon harvester is introduced to harvest the medial two-thirds of the tendon, while the distal insertion is left intact. The adductor magnus tendon is cut at 12-14 cm from its distal insertion and transferred into the patellar medial margin. Two suture anchors are inserted through the same incision at the superomedial aspect of the patella in the anatomic MPFL origin. The graft is tightened at 30 degrees knee flexion. Aftercare includes 4 weeks of brace treatment with restricted range of motion.

Gracilis tendon transfer associated with distal alignment for patella alta with recurrent dislocations: an original surgical technique.

PubMed

Marteau, E; Burdin, P; Brilhault, J-M

2011-06-01

Many surgical techniques for the medial patellofemoral ligament have recently been suggested, all of which included problems identifying the femoral anchorage point and determining the proper extent of knee flexion for the transplant. P. Burdin proposed a different and original approach consisting in performing a gracilis muscle transfer to the medial edge of the patella, thus obtaining progressive tension of the transfer during knee flexion by means of the myotatic reflex. We report the results herein. We retrospectively assessed 17 knees treated for patellofemoral instability using this technique. Two cases presented subjective patellofemoral instability and 15 presented objective patellofemoral instability. The patients' mean age was 17.4 years (range, 8-47 years) during the first episode of dislocation. Two cases of instability were secondary to advanced neuromuscular disease. Two knees had already undergone two stabilization attempts. Fifteen knees presented trochlear dysplasia (four stage A, eight stage B, and three stage C). The mean age at surgery was 28.2 years (range, 16-47 years). In 15 cases, the gracilis transfer was associated with lowering the anterior tibial tuberosity (mean, 10mm). No patellar fracture occurred. A persistent sensory deficit of the anterior branch of the internal saphenous nerve was observed in 15 cases. One knee remained painful and retained subjective instability; total knee arthroplasty was performed 3 years after the intervention. The mean follow-up at revision was 5.5 years (range, 1.5-16.5 years). No recurrence of dislocation was reported. Eight cases retained subjective instability. The SF-36 and IKDC scores were good or excellent in 12 cases and the KOOS was good or excellent in 13 cases. Radiologically, patellar tilt persisted in six cases out of 14, translation persisted in two cases out of 14, and secondary patella baja was observed in one. Medial patellofemoral osteoarthritis was observed in five cases: one case IWANO stage I and four cases IWANO stage II. These satisfactory results seem stable over time and were acquired using a simple procedure with reduced morbidity, making it possible to avoid significant displacement of the anterior tibial tuberosity and stabilize the extensor apparatus. It can also be hoped that the onset of secondary patellofemoral osteoarthritis, undoubtedly inevitable, has been delayed. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Adrenomedullin Regulates IL-1β Gene Expression in F4/80+ Macrophages during Synovial Inflammation

PubMed Central

Takano, Shotaro; Miyagi, Masayuki; Inoue, Gen; Aikawa, Jun; Iwabuchi, Kazuya; Takaso, Masashi

2017-01-01

Adrenomedullin (AM) plays an important role in the regulation of inflammatory processes; however, the role and expression of AM in synovial inflammation have not been determined. To investigate the expression and role of AM in inflamed synovial tissue (ST), the gene expression profiles of AM in the ST, including synovial macrophages and fibroblasts, of a murine patellar surgical dislocation model were characterized. In addition, the effects of interleukin- (IL-) 1β and AM in cultured synovial cells were also examined. CD11c+ macrophages were found to be elevated in ST of the surgically dislocated patella. Higher gene expression of CD11c, IL-1β, AM, receptor activity-modifying proteins 2 (RAMP2), and 3 (RAMP3) was also observed in ST obtained from the dislocated side. AM expression was also significantly increased in synovial fibroblasts and macrophages in response to IL-1β treatment. Synovial macrophages also highly expressed RAMP3 compared to fibroblasts and this expression was further stimulated by exogenously added IL-1β. Further, the treatment of the F4/80-positive cell fraction obtained from ST with AM inhibited IL-1β expression. Taken together, these findings demonstrated that AM was produced by synovial fibroblasts and macrophages in inflamed ST and that increased levels of AM may exert anti-inflammatory effects on synovial macrophages. PMID:28299347

Assessment of demographic and pathoanatomic risk factors in recurrent patellofemoral instability.

PubMed

Hiemstra, Laurie Anne; Kerslake, Sarah; Lafave, Mark

2017-12-01

The WARPS/STAID classification employs clinical assessment of presenting features and anatomic characteristics to identify two distinct subsets of patients within the patellofemoral instability population. The purpose of this study was to further define the specific demographics and the prevalence of risky pathoanatomies in patients classified as either WARPS or STAID presenting with recurrent patellofemoral instability. A secondary purpose was to further validate the WARPS/STAID classification with the Banff Patella Instability Instrument (BPII), the Marx activity scale and the Patellar Instability Severity Score (ISS). A convenience sample of 50 patients with recurrent patellofemoral instability, including 25 WARPS and 25 STAID subtype patients, were assessed. Clinical data were collected including assessment of demographic risk factors (sex, BMI, bilaterality of symptoms, affected limb side and age at first dislocation) and pathoanatomic risk factors (TT-TG distance, patella height, patellar tilt, grade of trochlear dysplasia, Beighton score and rotational abnormalities of the tibia or femur). Patients completed the BPII and the Marx activity scale. The ISS was calculated from the clinical assessment data. Patients were stratified into the WARPS or STAID subtypes for comparative analysis. An independent t test was used to compare demographics, the pathoanatomic risk factors and subjective measures between the groups. Convergent validity was tested with a Pearson r correlation coefficient between the WARPS/STAID and ISS scores. Demographic risk factors statistically associated with a WARPS subtype included female sex, age at first dislocation and bilaterality. Pathoanatomic risk factors statistically associated with a WARPS subtype included trochlear dysplasia, TT-TG distance, generalized ligamentous laxity, patellar tilt and rotational abnormalities. The independent t test revealed a significant difference between the ISS scores: WARPS subtype (M = 4.4, SD = 1.1) and STAID subtype (M = 2.5, SD = 1.5); t(48) = 5.2, p < 0.001. The relationship between the WARPS/STAID and the ISS scores, measured using a Pearson r correlation coefficient, demonstrated a strong relationship: r = -0.61, n = 50, p < 0.001. This study has demonstrated statistically significant evidence that certain demographics and pathoanatomies are more prevalent in each of the WARPS and STAID patellofemoral instability subtypes. There was no difference in quality-of-life or activity level between the subtypes. The WARPS/STAID score demonstrated convergent validity to the ISS and divergent validity to the BPII score and the Marx activity scale. This study has further validated both the WARPS/STAID classification and the ISS of patients that present with recurrent patellofemoral instability. III.

The Analysis of Risk Factors in No Thumb Test in Total Knee Arthroplasty

PubMed Central

Kim, Jee Hyoung; Ko, Dong Oh; Yoo, Chang Wook; Chun, Tae Hwan; Lee, Jung Soo

2011-01-01

Background We would like to analyze the risk factors of no thumb test among knee alignment tests during total knee arthroplasty surgery. Methods The 156 cases of total knee arthroplasty by an operator from October 2009 to April 2010 were analyzed according to preoperative indicators including body weight, height, degree of varus deformity, and patella subluxation and surgical indicators such as pre-osteotomy patella thickness, degree of patella degeneration, no thumb test which was evaluated after medial prepatella incision and before bone resection (1st test), no thumb test which was evaluated with corrective valgus stress (2nd test, J test), and the kind of prosthesis. We comparatively analyzed indicators affecting no thumb test (3rd test). Results There was no relation between age, sex, and body weight and no thumb test (3rd test). Patellar sulcus angle (p = 0.795), patellar congruence angle (p = 0.276) and preoperative mechanical axis showed no relationship. The 1st no thumb test (p = 0.007) and 2nd test (p = 0.002) showed significant relation with the 3rd no thumb test. Among surgical indicators, pre-osteotomy patella thickness (p = 0.275) and degeneration of patella (p = 0.320) were not relevant but post-osteotomy patellar thickness (p = 0.002) was relevant to no thumb test (3rd test). According to prosthesis, there was no significance with Nexgen (p = 0.575). However, there was significant correlation between Scorpio (p = 0.011), Vanguard (p = 0.049) and no thumb test (3rd test). Especially, Scorpio had a tendency to dislocate the patella, but Vanguard to stabilize the patella. Conclusions No thumb test (3rd test) is correlated positively with 1st test, 2nd test, and post-osteotomy patella thickness. Therefore, the more patella osteotomy and the prosthesis with high affinity to patellofemoral alignment would be required for correct patella alignment. PMID:22162789

A Novel Heterozygous Mutation in the T-box Protein 4 Gene in an Adult Case of Small Patella Syndrome.

PubMed

Oda, Tomoyuki; Matsushita, Masaki; Ono, Yohei; Kitoh, Hiroshi; Sakai, Tadahiro

2018-01-01

Small patella syndrome (SPS) is a rare skeletal dysplasia relating to the T-box protein 4 (TBX4) gene, which regulates the development of lower extremities. Patients typically present with recurrent patellar dislocation (RPD) in childhood or adolescence, leading to a diagnosis of SPS and subsequent treatment to improve activity levels. However, those with mild symptoms may not be diagnosed when young and present later after skeletal maturation, which might compromise treatment options. Further understanding of genetic mutations of SPS could possibly help early diagnosis and following adequate surgical treatment. In this case report, we present a surgically treated adult female case of RPD associated with SPS, carrying a novel heterozygous mutation in the TBX4 gene. A 19-year-old female presented with persistent right knee pain after an atraumatic episode ofpatellar dislocation during walking. The patient had a history of recurrent patella instability of the right knee with an onset at the age of 8 years due to a minor trauma. Patellar apprehension sign was positive bilaterally. There was radiological evidence of bilateral small patellae, hypoplastic femoral trochlea, and tibial tuberosity. A direct sequencing of the coding regions in the TBX4 gene had confirmed the diagnosis of SPS. A novel heterozygous mutation (p.L39PfsX35) was found in the patient and her father. Surgical treatment was indicated and the patient underwent an isolated medial patellofemoral ligament (MPFL) reconstruction while no distal realignment osteotomy was performed due to hypoplastic tibial tuberosity. Excellent subjective and objective outcomes were obtained at 1 year postoperatively. To the best of our knowledge, this is the first reported SPS case with a novel mutation in the TBX4 gene in an Asian population. While a satisfying short-term outcome was obtained by an isolated MPFL reconstruction, early genetic diagnosis in childhood with adequate surgical treatment (e.g., Roux-Goldthwait procedure) would be ideal considering the limited treatment options in skeletally matured patients. The reported case has added one mutation variant of the TBX4 gene, which may help prevent delays in diagnosis of SPS.

[Prevention and repair of patellar ligament injury in total knee arthroplasty].

PubMed

Bian, Yanyan; Weng, Xisheng

2013-09-01

To review the progress in the prevention and repair of patellar ligament injury in total knee Recent literature about the prevention and repair of patellar ligament injury in total knee arthroplasty arthroplasty. was reviewed and analyzed. Increased exposure can prevent the patellar ligament injury, and treatments of acute patellar ligament rupture can be obtained by simple repair, reconstruction with allograft materials or artificial materials, and auxiliary strengthening. Patellar ligament injury in total knee arthroplasty should not be ignored. Active prevention and repair of patellar ligament injury can obtain better function of knee joint.

Proximo-distal patellar position in three small dog breeds with medial patellar luxation.

PubMed

Wangdee, C; Theyse, L F H; Hazewinkel, H A W

2015-01-01

Medial patellar luxation is thought to be associated with a high proximal position of the patella in the trochlear groove. To determine whether the ratio of patellar ligament length and patellar length (L:P) is influenced by the stifle angle (75°, 96°, 113°, 130°, and 148°) in small dog breeds and to compare the L:P ratio in dogs of three small dog breeds with and without medial patellar luxation. A mediolateral radiograph of the stifle joint was used to measure the L:P ratio in the stifle joints of dogs of three small breeds with and without medial patellar luxation. The L:P ratio was evaluated at five stifle angles (75°, 96°, 113°, 130°, and 148°) in 14 cadavers (26 stifle joints) of small dog breeds in order to identify the best stifle angle to measure the L:P ratio. Then the mean ± SD L:P ratio was calculated for normal stifles and stifles with medial patellar luxation grades 1, 2, and 3 in 194 Pomeranians, 74 Chihuahuas, and 41 Toy or Standard Poodles. The L:P ratio was the same for all five stifle angles in the cadavers (p = 0.195). It was also not significantly different in the three breeds (p = 0.135), in normal and medial patellar luxation-affected stifles overall (p = 0.354), and in normal and medial patellar luxation-affected joints within each breed (p = 0.19). We conclude that a proximo-distal patellar position is not associated with medial patellar luxation in Pomeranians, Chihuahuas, and Toy or Standard Poodles. Thus a longer patellar ligament length does not play a role in the pathophysiology of medial patellar luxation in these small dog breeds.

Landing strategies of athletes with an asymptomatic patellar tendon abnormality.

PubMed

Edwards, Suzi; Steele, Julie R; McGhee, Deirdre E; Beattie, Sue; Purdam, Craig; Cook, Jill L

2010-11-01

Risk factors associated with a clinical presentation of patellar tendinopathy are patellar tendon ultrasonographic abnormality (PTA) and excessive loading. It remains unknown whether characteristics of an athlete's landing technique contribute to this excessive patellar tendon loading. This study investigated whether asymptomatic athletes with and without PTA had different landing strategies and hypothesized that asymptomatic athletes with a PTA would create higher patellar tendon loading and a different lower-limb landing strategy compared with athletes with normal patellar tendons. Seven athletes with no previous history or clinical signs of patellar tendon injury with a PTA were matched to athletes with normal patellar tendons (controls). Participants performed five successful trials of a stop-jump task, which involved a simultaneous two-foot horizontal and then vertical landing. During each trial, the participants' ground reaction forces and lower-limb electromyographic data were recorded, the three-dimensional kinematics measured, and the peak patellar tendon force calculated by dividing the net knee joint moment by the patellar tendon moment arm. Significant between-group differences in landing technique were mostly observed during the horizontal landing phase. Participants with a PTA created similar patellar tendon loading to the controls, but with altered sequencing, by landing with significantly greater knee flexion and extending their hips while the controls flexed their hips as they landed, reflecting a different muscle recruitment order compared with the PTA group. The crucial part in the development of PTA and, in turn, patellar tendinopathy may not be the magnitude of the patellar tendon load but rather the loading patterns. This research provides clinicians with important landing assessment criteria against which to identify athletes at risk of developing patellar tendinopathy.

Should the position of the patellar component replicate the vertical median ridge of the native patella?

PubMed

Lee, Rae Hyeong; Jeong, Hae Won; Lee, Jin Kyu; Choi, Choong Hyeok

2017-01-01

In total knee arthroplasty (TKA), the position of the patellar component can affect patellar tracking. However, the patellar component cannot always replicate the original high point of the patella because of anatomical variance. This study investigated whether altering the highest point of the patella can affect outcomes of primary TKA, especially in patients having a patella with a far-medialized median ridge. A retrospective review was performed for 177 knees (143 patients) treated with primary TKA between July 2011 and March 2014. Group 1 (34 knees) had the patellar component displaced over three millimeters from the median ridge, while Group 2 (143 knees) had the patellar component placed on the original median ridge position. The one-year follow-up outcomes were reviewed, including: patellar tilt angle, Knee Society Score, Feller Patellar Score, and modified Kujala Anterior Knee Pain Score. Mean (±standard deviation) displacement of the patellar component in Group 1 was 3.97±0.97mm lateral to the original position of the median ridge, with a significant decrease in lateral patellar tilt angle (P<0.001). Lateral patellar tilt showed a positive correlation with the medialization of the patellar component (P<0.001, r=0.401). Ability to rise from a chair was better in Group 1 (P=0.025). There were no other between-group differences in other clinical outcomes. There should be no need for the patellar component to replicate the original highest point of the native patella in primary TKA. Copyright © 2016 Elsevier B.V. All rights reserved.

Robot-aided in vitro measurement of patellar stability with consideration to the influence of muscle loading.

PubMed

Lorenz, Andrea; Bobrowitsch, Evgenij; Wünschel, Markus; Walter, Christian; Wülker, Nikolaus; Leichtle, Ulf G

2015-07-23

Anterior knee pain is often associated with patellar maltracking and instability. However, objective measurement of patellar stability under clinical and experimental conditions is difficult, and muscular activity influences the results. In the present study, a new experimental setting for in vitro measurement of patellar stability was developed and the mediolateral force-displacement behavior of the native knee analyzed with special emphasis on patellar tilt and muscle loading. In the new experimental setup, two established testing methods were combined: an upright knee simulator for positioning and loading of the knee specimens, and an industry robot for mediolateral patellar displacement. A minimally invasive coupling and force control mechanism enabled unconstrained motion of the patella as well as measurement of patellar motion in all six degrees of freedom via an external ultrasonic motion-tracking system. Lateral and medial patellar displacement were measured on seven fresh-frozen human knee specimens in six flexion angles with varying muscle force levels, muscle force distributions, and displacement forces. Substantial repeatability was achieved for patellar shift (ICC(3,1) = 0.67) and tilt (ICC(3,1) = 0.75). Patellar lateral and medial shift decreased slightly with increasing flexion angle. Additional measurement of patellar tilt provided interesting insights into the different displacement mechanisms in lateral and medial directions. For lateral displacement, the patella tilted in the same (lateral) direction, and tilted in the opposite direction (again laterally) for medial displacement. With regard to asymmetric muscle loading, a significant influence (p < 0.03, up to 5 mm shift and 8° tilt) was found for lateral displacement and a reasonable relationship between muscle and patellar force, whereas no effect was visible in the medial direction. The developed experimental setup delivered reproducible results and was found to be an excellent testing method for the in vitro analysis of patellar stability and future investigation of surgical techniques for patellar stabilization and total knee arthroplasty. We demonstrated a significant influence of asymmetric quadriceps loading on patellar stability. In particular, increased force application on the vastus lateralis muscle led to a clear increase of lateral patellar displacement.

Patella instability: building bridges across the ocean a historic review.

PubMed

Arendt, Elizabeth A; Dejour, David

2013-02-01

The diagnosis of and treatment for musculoskeletal disease and injuries have seen an explosion of new knowledge. More precise imaging, correlative injury anatomy, more focused physical examination features, among others, have led this upsurge of current insight. Crucial to this knowledge revolution is the expansion of international knowledge, which is aided by an adoption of a universal scientific language, electronic transfer of information, and personal communication of surgeons and scientists across national boundaries. One area where this is particularly evident is in our knowledge and treatment for patellofemoral disorders. This article will review the developments in the management of patellar dislocations by tracing their historical roots. This is not meant to be a comprehensive review, but rather to give current readers a "historical memory" upon which to judge and interpret our present-day bridge of knowledge. Level of evidence V.

The Effect of Patellar Thickness on Intraoperative Knee Flexion and Patellar Tracking in Patients With Arthrofibrosis Undergoing Total Knee Arthroplasty.

PubMed

Kim, Abraham D; Shah, Vivek M; Scott, Richard D

2016-05-01

We evaluated the intraoperative effect of patellar thickness on intraoperative passive knee flexion and patellar tracking during total knee arthroplasty (TKA) in patients with preoperative arthrofibrosis and compared them to patients with normal preoperative range of motion (ROM) documented in a prior study. Routine posterior cruciate ligament-retaining TKA was performed in a total of 34 knees, 23 with normal ROM and 11 with arthrofibrosis, defined as ≤100° of passive knee flexion against gravity under anesthesia. Once clinical balance and congruent patellar tracking were established, custom trial patellar components thicker than the standard trial by 2-mm increments (2-8 mm) were sequentially placed and trialed. Passive flexion against gravity was recorded using digital photograph goniometry. Gross mechanics of patellofemoral tracking were visually assessed. On average, passive knee flexion decreased 2° for every 2-mm increment of patellar thickness (P < .0001), which was similar to patients with normal preoperative ROM. In addition, increased patellar thickness had no gross effect on patellar subluxation and tilt in patients with arthrofibrosis as well as those with normal ROM. Patellar thickness had a modest effect on intraoperative passive flexion and no effect on patellar tracking in patients with arthrofibrosis undergoing TKA. There was no marked difference in intraoperative flexion and patellar tracking between patients with arthrofibrosis and patients with normal preoperative ROM. Copyright © 2016 Elsevier Inc. All rights reserved.

Clinical and biomechanical assessment of patella resurfacing in total knee arthroplasty.

PubMed

Berti, Lisa; Benedetti, Maria Grazia; Ensini, Andrea; Catani, Fabio; Giannini, Sandro

2006-07-01

Currently there is a limited understanding of the factors influencing range of motion by comparing patellar resurfacing vs non-resurfacing in total knee arthroplasty during activities of daily living. A recent meta-analysis of patellar replacement confirms better outcome with patella resurfacing; however, the result can be influenced by many other factors, such as: component design, surgeon experience, and technical aspects of the surgery. This study compares the biomechanics of the knee in patients after total knee arthroplasty with and without patellar resurfacing during stair climbing. Forty-seven patients with total knee arthroplasty were assessed at the mean follow-up of 24 months. In all of them a posterior stabilised fixed bearing prosthesis (Optetrak PS, Exactech) was implanted. Twenty-six patients were treated without patellar resurfacing and 21 with patellar resurfacing. Clinical evaluations were performed using the International Knee Society and the Hospital for Special Surgery scores. Ten patients with patellar resurfacing and 10 patients without patellar resurfacing were also studied with motion analysis during stair climbing; 10 healthy subjects were studied for statistical comparison. Clinical passive knee flexion, International Knee Society Function and Hospital for Special Surgery scores were significantly higher in the patellar resurfacing group. During stair climbing, active knee joint range of motion during the stance phase was greater in patients with patellar resurfacing. The maximum adduction moment was significantly higher in the group without patellar resurfacing. Patients with patellar resurfacing demonstrated better clinical scores, and kinematic and kinetic data while ascending stairs.

Abnormal Patella Height Based on Insall-Salvati Ratio and its Correlation with Patellar Cartilage Lesions: An Extremity-Dedicated Low-Field Magnetic Resonance Imaging Analysis of 1703 Chinese Cases.

PubMed

Lu, W; Yang, J; Chen, S; Zhu, Y; Zhu, C

2016-09-01

Diagnostic performance of patellar position for patellar cartilage lesions remains unclear. The aim of this study was to assess the abnormal patella height and its correlation with chondral lesions of the patellofemoral joint in China. A total of 1703 consecutive patients who performed knee joint examination using an extremity-dedicated low-field magnetic resonance imaging were enrolled in this study. Patellar cartilage lesions were diagnosed based on the result of magnetic resonance imaging and clinical data. Patella height was defined as the ratio of patellar tendon length to patellar length according to Insall-Salvati index. Patella alta and infera were defined as tendon length/patellar length >1.2 and <0.8, respectively. The total prevalence of patellar cartilage lesions was 38.0%. The prevalence in females was significantly higher than that in males (46.4% vs 28.8%, p < 0.001). Age notably increased the incidence of patellar cartilage lesions (p < 0.001). Logistic regression analysis showed that tendon length/patellar length ratio was significantly correlated with patellar cartilage lesions (odds ratio = 6.380, p < 0.001). Furthermore, patients with cartilage lesions showed significantly higher rates of patella alta and infera (p < 0.001). In addition, receiver operating characteristic curve analysis demonstrated that abnormal patella height had statistical significance in diagnosing cartilage lesions (p < 0.001). However, the area under the curve (0.596; 95% confidence interval: 0.568-0.624) and sensitivity (47.0%) were relatively low, while the specificity was 72.2%. Patients with patellar cartilage lesions have an increased tendon length/patellar length ratio. The abnormal patella height is significantly correlated with chondral lesions and can be used as a potential diagnostic marker. © The Finnish Surgical Society 2015.

Isolated patellofemoral arthroplasty reproduces natural patellofemoral joint kinematics when the patella is resurfaced.

PubMed

Vandenneucker, Hilde; Labey, Luc; Vander Sloten, Jos; Desloovere, Kaat; Bellemans, Johan

2016-11-01

The objectives of this in vitro project were to compare the dynamic three-dimensional patellofemoral kinematics, contact forces, contact areas and contact pressures of a contemporary patellofemoral prosthetic implant with those of the native knee and to measure the influence of patellar resurfacing and patellar thickness. The hypothesis was that these designs are capable to reproduce the natural kinematics but result in higher contact pressures. Six fresh-frozen specimens were tested on a custom-made mechanical knee rig before and after prosthetic trochlear resurfacing, without and with patellar resurfacing in three different patellar thicknesses. Full three-dimensional kinematics were analysed during three different motor tasks, using infrared motion capture cameras and retroflective markers. Patellar contact characteristics were registered using a pressure measuring device. The patellofemoral kinematic behaviour of the patellofemoral arthroplasty was similar to that of the normal knee when the patella was resurfaced, showing only significant (p < 0.0001) changes in patellar flexion. Without patellar resurfacing, significant more patellar flexion, lateral tilt and lateral rotation was noticed. Compared to the normal knee, contact pressures were significantly elevated after isolated trochlear resurfacing. However, the values were more than doubled after patellar resurfacing. Changes in patellar thickness only influenced the antero-posterior patellar position. There was no other influence on the kinematics, and only a limited influence on the contact pressures in the low flexion angles. The investigated design reproduced the normal patellofemoral kinematics acceptable well when the patella was resurfaced. From a kinematic point of view, patellar resurfacing may be advisable. However, the substantially elevated patellar contact pressures remain a point of concern in the decision whether or not to resurface the patella. This study therefore not only adds a new point in the discussion whether or not to resurface the patella, but also supports the claimed advantage that a patellofemoral arthroplasty is capable to reproduce the natural knee kinematics.

Eliminating impingement optimizes patellar biomechanics in high knee flexion.

PubMed

Tang, Qi-heng; Zhou, Yi-xin; Tang, Jing; Shao, Hong-yi; Wang, Guang-zhi

2010-08-01

We investigated the impact of eliminating the impingement between extensor mechanism and tibial insert on patellar tracking and patellar ligament tension in high knee flexion. Six cadaveric specimens were tested on an Oxford-type testing rig. The Genesis II knee system was implanted into each specimen knee with the traditional tibial insert and high-flex insert successively. Compared to traditional insert, the high-flex insert was characterized with a chambered anterior post and a chambered anterior lip which eliminates patella-post and patellar ligament-anterior lip impingements. The patella was tracked with an NDI Optotrak Certus system. The patellar ligament tension was measured using a NKB S-type tension transducer. There was a decrease of resultant patellar translation relative to the femur with statistically significant (P<0.05) at 90 degrees to 150 degrees of knee flexion and a decrease of patellar ligament tension with statistical significance (P<0.05) at 100 degrees, 120 degrees, 130 degrees, and 140 degrees of flexion using high-flex insert compared to traditional insert. Eliminating the impingement between extensor mechanism and implant in high knee flexion altered patellar tracking and reduced patellar ligament tension, which would facilitate high knee flexion.

Effects of a Knee Brace With a Patellar Hole Versus Without a Patellar Hole in Patients With Knee Osteoarthritis: A Double-Blind, Randomized Controlled Trial.

PubMed

Added, Marco Aurélio Nemitalla; Added, Caroline; Kasawara, Karina Tamy; Rotta, Viviane Perez; de Freitas, Diego Galace

2017-01-01

The objective of this study was to observe the immediate effect of a knee brace with a patellar hole versus without a patellar hole on pain perception in patients with knee osteoarthritis. To accomplish this, a double-blind, randomized controlled trial enrolled 108 patients divided into two groups (knee brace with a patellar hole or without a patellar hole). Patients were evaluated by the Visual Analogue Scale (VAS) in order to measure their pain sensation, the Timed Up and Go (TUG) test was used to evaluate their ability to walk, and the 8-m walking test (8MWT) was used to estimate their walking speed. Both groups presented significant reduction in pain perception, higher function of the lower extremities, and greater mobility while wearing a knee brace. However, the patients who wore a knee brace without a patellar hole presented more favorable results than those who wore a knee brace with a patellar hole: a 1.6-point reduction was found versus 1.1 points in the VAS, the patients presented 0.7 s less time versus 0.4 s in the TUG, and the speed was reduced by 1.4 s versus 0.8 s in the 8MWT. Therefore, the knee brace without a patellar hole presented more favorable results when compared with the knee brace with a patellar hole.

Repair of Medial Patellofemoral, Ligament Improves Patellar, Tracking in Total Knee Replacement.

PubMed

Meneghini, R Michael; Ziemba-Davis, Mary; Smits, Shelly; Bicos, James

2015-11-01

The medial patellofemoral ligament (MPFL) is essential to maintain patella stability; however, its role in total knee replacement (TKR) has not been studied. Forty-six consecutive TKRs in 40 patients were reviewed. Standard closure was performed in 29 TKRs. The MPFL was isolated and anatomically re-approximated in 17 subsequent TKRs. Blinded radiographic evaluation of patellar tilt and subluxation was performed preoperatively and 4 months postoperatively. Despite greater preoperative lateral tilt, the MPFL repair group demonstrated greater correction in patellar tilt compared with the standard closure group (p = 0.02). Patellar tracking also was optimized in the MPFL group, despite equivalent preoperative lateral patellar subluxation in the two groups. Simple repair of the MPFL at arthrotomy closure appears to optimize patellar stability radiographically and may improve long-term results by minimizing patellar complications and wear.

[Patella fractures in knee arthroplasty].

PubMed

Roth, A; Ghanem, M; Fakler, J

2016-05-01

Periprosthetic patella fractures occur both with and without retropatellar joint replacement. A non-operative treatment yields satisfactory results with low morbidity. It can be applied in minimally displaced fractures that have an intact retropatellar component and an intact extensor mechanism, combined with an initial immobilization. The surgical treatment is associated with relatively poor results and with high complication rates. There was only minor improvement of functional results, no matter which surgical technique was used. Surgical intervention is still required in fractures with a loosening of the patellar component, considerable dislocations of fragments, and damage to or rupture of the extensor mechanism. In particular, type II fractures require repair of the extensor mechanism and the fracture or patellectomy. Type III fractures require a revision or resection of the patella, a patelloplasty or total patellectomy. In addition, early or late reconstruction using allograft to restore the extensor mechanism can be taken in consideration.

Outcome and clinical signs of arthroscopically graded patellar chondromalacia with or without lateral release.

PubMed

Korkala, O L; Isotalo, T M; Lavonius, M I; Niskanen, R O

1995-01-01

In a follow-up study of 67 patients with an arthroscopically diagnosed patellar chondromalacia, we compared the results of plain conservative treatment with those after an open lateral retinacular release. The mean follow-up was 35 months. In Grade I chondromalacia the lateral release did not affect the result, which was in all cases good or excellent. In Grade II to IV chondromalacia the lateral release appeared beneficial, although the difference did not reach statistical significance. We also examined the validity of three clinical signs in arthroscopically verified patellar chondromalacia. Patellar inhibition and tracking tests were clearly more sensitive than the lateral apprehension test, which often gave a false negative result. If the patellar inhibition test is positive and a Grade II to IV chondromalacia of the patella is found at arthroscopy, lateral release should be considered among other procedures, like patellar shaving or patellar resurfacing.

Patellar metastasis from primary tumor

PubMed Central

Li, Gang; Shan, Changxing; Sun, Ran; Liu, Song; Chen, Song; Song, Mingzhi; Lu, Ming

2018-01-01

Although bone tumors are frequently located in the knee area, primary tumors of the patella are rare and patellar metastases are even rarer. Knee pain is the most common complaint of patients with patellar metastases. Owing to the low incidence of patellar metastases, misdiagnosis is not unusual. The present review analyzes ~44 cases of patellar metastases originating from distinct primary sites. Reports of malignant tumors of the lung and kidney metastasizing to the patella were more common than those of other patellar metastases. Relative incidence, symptomatology, imaging features, histopathology and treatment options for these patellar metastatic lesions are described respectively along with a review of the literature. Despite numerous experiments demonstrating the reasons for implantation of tumor in patella, the answer to this question has not yet been revealed. In the light of the increasing attention on the diagnosis and the treatment of these lesions, the availability of the integrated information regarding metastases in the patella becomes more relevant. PMID:29434829

21 CFR 888.3580 - Knee joint patellar (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 patellar (hemi-knee) metallic... § 888.3580 Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis. (a) Identification. A knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis is a device made of...

Patellar Sleeve Fracture With Ossification of the Patellar Tendon.

PubMed

Damrow, Derek S; Van Valin, Scott E

2017-03-01

Patellar sleeve fractures make up greater than 50% of all patellar fractures. They are essentially only seen in the pediatric population because of the thick periosteum and the distal patellar pole apophysis in this group. These fractures can lead to complications if not treated appropriately and in a timely fashion. Complications of missed or untreated patellar sleeve fractures include patella alta, anterior knee pain, and quadriceps atrophy. These can all result in severe limitations in activity. The authors describe a case of a 16-year-old boy who sustained a patellar sleeve fracture 3 years prior to presentation. On presentation, he had patella alta, diminished strength, 5° of extensor lag, and radiographs that revealed bone formation along the patellar tendon. Despite this, he was able to maintain a high level of activity. This case report explores how the patient could have maintained a high level of activity despite having a patellar sleeve fracture. Also, because of the delayed presentation, the patella was ossified and the quadriceps was retracted, which led to a novel approach to reconstructing his distal extensor mechanism. This approach included a V-Y advancement of the quadriceps tendon and patellar tendon reconstruction using the patient's hamstring tendon (semitendinosus). This technique, combined with physical therapy postoperatively, resulted in his return to varsity high school soccer. To the best of the authors' knowledge, this technique has not been reported for this rare condition. [Orthopedics. 2017; 40(2):e357-e359.]. Copyright 2016, SLACK Incorporated.

The influence of intraoperative soft tissue balance on patellar pressure in posterior-stabilized total knee arthroplasty.

PubMed

Matsumoto, Tomoyuki; Shibanuma, Nao; Takayama, Koji; Sasaki, Hiroshi; Ishida, Kazunari; Matsushita, Takehiko; Kuroda, Ryosuke; Kurosaka, Masahiro

2016-06-01

Appropriate soft tissue balance is essential for the success of total knee arthroplasty (TKA), and assessment with an offset-type tensor provides useful information about the femorotibial (FT) joint. The purpose of the study was to investigate the relationship between intraoperative soft tissue balance and patellar pressure at both medial and lateral sides. Thirty varus-type osteoarthritis patients who received mobile-bearing posterior-stabilized TKAs were enrolled in the study. Using the tensor, soft tissue balance, including joint component gap and varus ligament balance, was recorded at 0°, 10°, 30°, 60°, 90°, 120°, and 135° with patellofemoral (PF) joint reduction and femoral component placement. Following final prostheses implanted with appropriate insert, the medial and lateral patellar pressures were measured at each flexion angle. A simple regression analysis was performed between each patellar pressure, parameter of soft tissue balance, and postoperative flexion angle. Both lateral and medial patellar pressures increased with flexion. The lateral patellar pressure was significantly higher than the medial patellar pressure at 60°, 90°, and 135° of flexion (p<0.05). The lateral patellar pressure inversely correlated with the varus ligament balance at 60° and 90° of flexion (p<0.05). The lateral patellar pressure at 120° and 135° of flexion inversely correlated with the postoperative flexion angle (p<0.05). Soft tissue balance influenced patellar pressure. In particular, a reduced lateral patellar pressure was found at the lateral laxity at flexion, leading to high postoperative flexion angle. III. Copyright © 2016 Elsevier B.V. All rights reserved.

Isolated and combined medial patellofemoral ligament reconstruction in revision surgery for patellofemoral instability: a prospective study.

PubMed

Kohn, Ludwig M; Meidinger, Gebhart; Beitzel, Knut; Banke, Ingo J; Hensler, Daniel; Imhoff, Andreas B; Schöttle, Philip B

2013-09-01

Persistent pain and redislocations after surgical treatment of patellofemoral instability are described in up to 40% of patients. However, prospective outcome data about revision surgery are missing. To evaluate the clinical outcome after revision medial patellofemoral ligament (MPFL) reconstruction using isolated and combined procedures, with a follow-up of 24 months. Case series; Level of evidence, 4. Study participants were 42 patients (median age, 22 years; range, 13-46 years) who underwent revision surgery between January 2007 and December 2009 because of persistent patellofemoral instability after a mean of 1.8 previous failed surgical interventions (lateral release, medial imbrication/vastus medialis obliquus distalization, medialization of the tuberosity). An isolated MPFL reconstruction was performed in 15 cases, while a combination procedure was performed in 27 cases. The clinical results were evaluated preoperatively and 24 months postoperatively using the International Knee Documentation Committee (IKDC), Kujala, and Tegner scores as well as a subjective questionnaire. Patellar shift, tilt, and height, as well as level of degeneration, were defined preoperatively and at the latest follow-up on plain radiographs and magnetic resonance imaging. At 24-month follow-up, 87% of the patients were satisfied or very satisfied with the treatment. No apprehension or redislocation was reported at follow-up, and there was a significant decrease in pain during daily activities. There were significant improvements (P < .001) in IKDC (from 50 to 80), Kujala (from 51 to 85), and Tegner scores (from 2.4 to 4.9). Patellar shift, tilt, and height decreased significantly (P < .05) to anatomic values, and there was no aggravation to the level of pre-existing degeneration. No significant difference was noticed between the isolated and combined procedures. As patellofemoral instability is a multifactorial problem, revision surgery should be indicated only after a comprehensive examination. The results of this study show that MPFL reconstruction, alone or in combination, seems to be an effective treatment for recurrent patellar dislocations after a failed previous surgery, leading to significant increases in stability and functionality as well as a reduction in pain.

Superolateral Hoffa's fat pad (SHFP) oedema and patellar cartilage volume loss: quantitative analysis using longitudinal data from the Foundation for the National Institute of Health (FNIH) Osteoarthritis Biomarkers Consortium.

PubMed

Haj-Mirzaian, Arya; Guermazi, Ali; Hafezi-Nejad, Nima; Sereni, Christopher; Hakky, Michael; Hunter, David J; Zikria, Bashir; Roemer, Frank W; Demehri, Shadpour

2018-04-12

To determine the association of superolateral Hoffa's fat pad (SHFP) oedema and patellofemoral joint structural damage in participants of Foundation for the National Institute of Health Osteoarthritis Biomarkers Consortium study. Baseline and 24-month MRIs of 600 subjects were assessed. The presence of SHFP oedema (using 0-3 grading scale) and patellar morphology metrics were determined using baseline MRI. Quantitative patellar cartilage volume and semi-quantitative MRI osteoarthritis knee score (MOAKS) variables were extracted. The associations between SHFP oedema and patellar cartilage damage, bone marrow lesion (BML), osteophyte and morphology were evaluated in cross-sectional model. In longitudinal analysis, the associations between oedema and cartilage volume loss (defined using reliable change index) and MOAKS worsening were evaluated. In cross-sectional evaluations, the presence of SHFP oedema was associated with simultaneous lateral patellar cartilage/BML defects and inferior-medial patellar osteophyte size. A significant positive correlation between the degree of patella alta and SHFP oedema was detected (r = 0.259, p < 0.001). The presence of oedema was associated with 24-month cartilage volume loss (odds ratio (OR) 2.11, 95% confidence interval 1.46-3.06) and medial patellar BML size (OR 1.92 (1.15-3.21)) and number (OR 2.50 (1.29-4.88)) worsening. The optimal cut-off value for the grade of baseline SHFP oedema regarding both presence and worsening of patellar structural damage was ≥ 1 (presence of any SHFP hyperintensity). The presence of SHFP oedema could be considered as a predictor of future patellar cartilage loss and BML worsening, and an indicator of simultaneous cartilage, BML and osteophyte defects. • SHFP oedema was associated with simultaneous lateral patellar OA-related structural damage. • SHFP oedema was associated with longitudinal patellar cartilage loss over 24 months. • SHFP oedema could be considered as indicator and predictor of patellar OA.

Bilateral Patellar Tendon Rupture

DTIC Science & Technology

2009-07-01

Bilateral patellar tendon rupture Military Medicine Radiology Corner, Volume 173, July, 2009...Radiology Corner Bilateral patellar tendon rupture (#37) Guarantor: 2dLt Ramon A. Riojas, USAF, MSC1 Contributors: 2dLt Ramon A. Riojas...with the abbreviated answer in the July 2009 issue. 1 The authors present a case of bilateral patellar tendon rupture in an active duty male exiting

Is latero-medial patellar mobility related to the range of motion of the knee joint after total knee arthroplasty?

PubMed

Ota, Susumu; Nakashima, Takeshi; Morisaka, Ayako; Omachi, Takaaki; Ida, Kunio; Kawamura, Morio

2010-12-01

Diminished range of motion (ROM) of the knee joint after total knee arthroplasty (TKA) is thought to be related to reduced patellar mobility. This has not been confirmed clinically due to a lack of quantitative methods adequate for measuring patellar mobility. We investigated the relationship between patellar mobility by a reported quantitative method and knee joint ROM after TKA. Forty-nine patients [osteoarthritis--OA: 29 knees; rheumatoid arthritis--RA: 20 knees] were examined after TKA. Respective medial and lateral patellar mobility was measured 1 and 6 months postoperatively using a patellofemoral arthrometer (PFA). Knee joint ROM was also measured in each of those 2 sessions. Although the flexion and extension of the knee joints improved significantly from 1 to 6 months after TKA, the medial and lateral patellar displacements (LPDs) failed to improve during that same period. Moreover, only the changes in knee flexion and medial patellar displacement (MPD) between the two sessions were positively correlated (r = 0.31, p < 0.05). However, our findings demonstrated that medial and lateral patellar mobility had no sufficient longitudinal relationship with knee ROM after TKA. Copyright © 2010 Elsevier Ltd. All rights reserved.

[Treatment of conmminuted patellar fractures with internal Ni-Ti patellar concentrator and tension bind wire fixation].

PubMed

Tan, Hong-lie; Qian, Chen; Zhao, Jin-kun; Shi, Yan; Zhou, Qi

2009-02-01

To study the clinical efficacy of the treatment of comminuted patellar fractures with internal NiTi-Patellar concentrator and tension bind wire fixation. From March 2004 to June 2007, 38 cases of fresh comminuted patellar fractures were treated with internal NiTi-Patellar concentrator and tension bind wire fixation. There were 25 males and 13 females,ranging from 21 to 64 years (mean 42.5 years). All were comminuted fractures with displacement, 16 cases were 3 fragments, 14 cases were 4 fragments, 8 cases were 5 fragments. There were other fractures in 8 cases. During followed-up, knee function and complications were evaluated. All patients were followed up for 8 to 24 months (mean 15 months) and obtained complete bone union. No case of implant was loosening and fragment displacement, traumatic arthritis occured in 2 cases. Under Lysholm & Gillquist score, the results were excellent in 17 cases, good in 19, fair in 2. Internal Ni-Ti-Patellar concentrator and tension bind wire fixation is one of the ideal methods for the treatment of comminuted patellar fracture, which could provide satisfied reduction, reliable fixation and good functional recovery.

Is it possible to re-establish pre-operative patellar kinematics using a ligament-balanced technique in total knee arthroplasty? A cadaveric investigation.

PubMed

Keshmiri, Armin; Springorum, Hans; Baier, Clemens; Zeman, Florian; Grifka, Joachim; Maderbacher, Günther

2015-03-01

Several authors emphasise that the appearance of patellar maltracking after total knee arthroplasty (TKA) is caused by rotational malalignment of the femoral and tibial components. Ligament-balanced femoral component rotation was not found to be associated with abnormal postoperative patellar position. We hypothesised that a ligament-balanced technique in TKA has the ability to best re-establish patellar kinematics. In ten cadaveric knees TKA was performed assessing femoral rotation in ligament-balanced and different femoral and tibial component rotation alignments. Patellar kinematics after different component rotations were analysed using a commercial computer navigation system. Ligament-balanced femoral rotation showed the best re-establishment of patellar kinematics after TKA compared to the healthy pre-operative knee. In contrast to tibial component rotation, femoral component rotation had a major impact on patellofemoral kinematics. This investigation suggests that a ligament-balanced technique in TKA is most likely to re-establish natural patellofemoral kinematics. Tibial component rotation did not influence patellar kinematics.

Patellar tendon re-rupture on the opposite end of the previous site of surgical repair

PubMed Central

KOH, Bryan Thean Howe; SAYAMPANATHAN, Andrew A; LEE, Keng Thiam

2017-01-01

We describe a rare case of a patellar tendon “re-rupture” at the opposite end of a previous proximal tendon repair. A 32-year-old male with a history of surgically repaired right proximal patellar tendon rupture presented with an acute non-traumatic right knee pain and instability during sports. Magnetic resonance imaging confirmed a complete rupture of his distal patellar tendon at the tibial tuberosity. The patellar tendon was repaired using two 5.5 mm BioCorkscrews (Arthrex) inserted into the tibial tuberosity; the tendon was stitched with the No. 2 fiberwires using Krackow technique. As the patellar tendon was degenerative, the repair was augmented with a semitendinosus tendon harvested using an open tendon stripper, leaving the distal attachment intact. At 2.6 years followup he had mild anterior knee pain, range of motion 0-130° and was able to squat. MRI scan done at followup revealed good healing of repaired patellar tendon. PMID:28566788

Excessive lateral patellar translation on axial computed tomography indicates positive patellar J sign.

PubMed

Xue, Zhe; Song, Guan-Yang; Liu, Xin; Zhang, Hui; Wu, Guan; Qian, Yi; Feng, Hua

2018-03-20

The purpose of the study was to quantify the patellar J sign using traditional computed tomography (CT) scans. Fifty-three patients (fifty-three knees) who suffered from recurrent patellar instability were included and analyzed. The patellar J sign was evaluated pre-operatively during active knee flexion and extension. It was defined as positive when there was obvious lateral patellar translation, and negative when there was not. The CT scans were performed in all patients with full knee extension; and the parameters including bisect offset index (BOI), patellar-trochlear-groove (PTG) distance, and patellar lateral tilt angle (PLTA) were measured on the axial slices. All the three parameters were compared between the J sign-positive group (study group) and the J sign-negative group (control group). In addition, the optimal thresholds of the three CT scan parameters for predicting the positive patellar J sign were determined with receiver operating characteristic (ROC) curves, and the diagnostic values were assessed by the area under the curve (AUC). Among the fifty-three patients (fifty-three knees), thirty-seven (70%) showed obvious lateral patellar translation, which were defined as positive J sign (study group), and the remaining sixteen (30%) who showed no lateral translation were defined as negative J sign (control group). The mean values of the three CT parameters in the study group were all significantly larger compared to the control group, including BOI (121 ± 28% vs 88 ± 12%, P = 0.038), PTG distance (5.2 ± 6.6 mm vs - 4.4 ± 5.2 mm, P < 0.05), and PLTA (34.9 ± 10.5° vs 25.7 ± 3.4°, P = 0.001). Furthermore, the evaluation of ROC analysis showed that the AUC of BOI was the largest (AUC = 0.906) among the three parameters, and the optimal threshold of BOI to predict the positive patellar J sign was 97.5% (Sensitivity = 83.3%, Specificity = 87.5%). In this study, the prevalence of positive patellar J sign was 70%. The BOI measured from the axial CT scans of the knee joint can be used as an appropriate predictor to differentiate the positive J sign from the negative J sign, highlighting that the excessive lateral patellar translation on axial CT scan indicates positive patellar J sign. IV.

Does patellofemoral congruence following total knee arthroplasty correlate with pain or function? Intraoperative arthroscopic assessment of 30 cases

PubMed Central

Senioris, Antoine; Rahali, Said; Malekpour, Louis; Dujardin, Franck; Courage, Olivier

2016-01-01

Background Anterior knee pain (AKP) is observed in total knee arthroplasty (TKA) both with and without patellar resurfacing, and neither patellar denervation nor secondary resurfacing are effective for treating the symptoms. The exact causes for pain remain unclear, though abnormal patellofemoral forces due to patellar malalignment or inadequate implant design can play an important role. The purpose of this study was to arthroscopically evaluate patellofemoral congruence after wound closure following TKA without patellar resurfacing and correlate it to patellar morphology and postoperative pain and function. Methods The authors prospectively studied 30 patients that received uncemented mobile-bearing TKA. Patellofemoral congruence was assessed arthroscopically after wound closure by estimating the contact area between the native patella and the prosthetic trochlea (> two-thirds, > one-third, < one-third). The findings were correlated to preoperative assessments of patellar geometry (Wiberg classification using X-rays) and clinical outcomes [Knee Society Score (KSS), AKP on Visual Analogic Scale (VAS), and patient satisfaction]. Results Knees of 22 women and 8 men aged 69.8 years (range, 61–84 years) were analyzed at 16 months (range, 12–23 months). Preoperative patellar geometry was Wiberg type A in 11, type B in 12 and type C in 7 knees. Postoperative KSS was 79.1 (range, 50.0–94) and the VAS for AKP was 1.6±1.3 (median, 1; range, 0–5). Patellar congruence was correlated with patellar morphology (P<0.001) but not correlated with any clinical outcomes (KSS, VAS or satisfaction). There were also no statistical correlations between patellar morphology or patellofemoral congruence and patient characteristics. Conclusions While patellar morphology and patellofemoral congruence are strongly related, they are not associated with clinical outcomes or patient demographics. Considering that numerous incongruent patellofemoral joints were pain-free, and conversely, many perfectly congruent patellofemoral joints had anterior pain, the authors suppose that pain is probably caused by mechanisms other than patellofemoral pressures. PMID:27570773

Does patellofemoral congruence following total knee arthroplasty correlate with pain or function? Intraoperative arthroscopic assessment of 30 cases.

PubMed

Senioris, Antoine; Saffarini, Mo; Rahali, Said; Malekpour, Louis; Dujardin, Franck; Courage, Olivier

2016-08-01

Anterior knee pain (AKP) is observed in total knee arthroplasty (TKA) both with and without patellar resurfacing, and neither patellar denervation nor secondary resurfacing are effective for treating the symptoms. The exact causes for pain remain unclear, though abnormal patellofemoral forces due to patellar malalignment or inadequate implant design can play an important role. The purpose of this study was to arthroscopically evaluate patellofemoral congruence after wound closure following TKA without patellar resurfacing and correlate it to patellar morphology and postoperative pain and function. The authors prospectively studied 30 patients that received uncemented mobile-bearing TKA. Patellofemoral congruence was assessed arthroscopically after wound closure by estimating the contact area between the native patella and the prosthetic trochlea (> two-thirds, > one-third, < one-third). The findings were correlated to preoperative assessments of patellar geometry (Wiberg classification using X-rays) and clinical outcomes [Knee Society Score (KSS), AKP on Visual Analogic Scale (VAS), and patient satisfaction]. Knees of 22 women and 8 men aged 69.8 years (range, 61-84 years) were analyzed at 16 months (range, 12-23 months). Preoperative patellar geometry was Wiberg type A in 11, type B in 12 and type C in 7 knees. Postoperative KSS was 79.1 (range, 50.0-94) and the VAS for AKP was 1.6±1.3 (median, 1; range, 0-5). Patellar congruence was correlated with patellar morphology (P<0.001) but not correlated with any clinical outcomes (KSS, VAS or satisfaction). There were also no statistical correlations between patellar morphology or patellofemoral congruence and patient characteristics. While patellar morphology and patellofemoral congruence are strongly related, they are not associated with clinical outcomes or patient demographics. Considering that numerous incongruent patellofemoral joints were pain-free, and conversely, many perfectly congruent patellofemoral joints had anterior pain, the authors suppose that pain is probably caused by mechanisms other than patellofemoral pressures.

Patellar tendon healing with platelet-rich plasma: a prospective randomized controlled trial.

PubMed

de Almeida, Adriano Marques; Demange, Marco Kawamura; Sobrado, Marcel Faraco; Rodrigues, Marcelo Bordalo; Pedrinelli, André; Hernandez, Arnaldo José

2012-06-01

The patellar tendon has limited ability to heal after harvesting its central third. Platelet-rich plasma (PRP) could improve patellar tendon healing. Adding PRP to the patellar tendon harvest site would improve donor site healing and improve clinical outcome at 6 months after anterior cruciate ligament (ACL) reconstruction with a patellar tendon graft. Randomized controlled trial; Level of evidence, 1. Twenty-seven patients were randomly divided to receive (n = 12) or not receive (n = 15) PRP in the patellar tendon harvest site during ACL reconstruction. The primary outcome was magnetic resonance imaging (MRI) assessment of patellar tendon healing (gap area) after 6 months. Secondary outcomes were questionnaires and isokinetic testing of ACL reconstruction with a patellar tendon graft comparing both groups. Patellar tendon gap area was significantly smaller in the PRP group (4.9 ± 5.3 mm(2); 95% confidence interval [CI], 1.1-8.8) than in the control group (9.4 ± 4.4 mm(2); 95% CI, 6.6-12.2; P = .046). Visual analog scale score for pain was lower in the PRP group immediately postoperatively (3.8 ± 1.0; 95% CI, 3.18-4.49) than in the control group (5.1 ± 1.4; 95% CI, 4.24-5.90; P = .02). There were no differences after 6 months in questionnaire and isokinetic testing results comparing both groups. We showed that PRP had a positive effect on patellar tendon harvest site healing on MRI after 6 months and also reduced pain in the immediate postoperative period. Questionnaire and isokinetic testing results were not different between the groups at 6 months.

Re-revision of a patellar tendon rupture in a young professional martial arts athlete.

PubMed

Vadalà, A; Iorio, R; Bonifazi, A M; Bolle, G; Ferretti, A

2012-09-01

A 27-year-old professional martial arts athlete experienced recurrent right knee patellar tendon rupture on three occasions. He underwent two operations for complete patellar tendon rupture: an end-to-end tenorrhaphy the first time, and revision with a bone-patellar-tendon (BPT) allograft. After the third episode, he was referred to our department, where we performed a surgical reconstruction with the use of hamstring pro-patellar tendon, in a figure-of-eight configuration, followed by a careful rehabilitation protocol. Clinical and radiological follow-ups were realized at 1, 3, and 6 months and 1 and 2 years postop, with an accurate physical examination, the use of recognized international outcome scores, and radiograph and MRI studies. As far as we know, this is the first paper to report a re-revision of a patellar tendon rupture.

Similar patient-reported outcomes and performance after total knee arthroplasty with or without patellar resurfacing

PubMed Central

Ali, Abdulemir; Lindstrand, Anders; Nilsdotter, Anna; Sundberg, Martin

2016-01-01

Background and purpose Knee pain after total knee arthroplasty (TKA) is not uncommon. Patellar retention in TKA is one cause of postoperative knee pain, and may lead to secondary addition of a patellar component. Patellar resurfacing in TKA is controversial. Its use ranges from 2% to 90% worldwide. In this randomized study, we compared the outcome after patellar resurfacing and after no resurfacing. Patients and methods We performed a prospective, randomized study of 74 patients with primary osteoarthritis who underwent a Triathlon CR TKA. The patients were randomized to either patellar resurfacing or no resurfacing. They filled out the VAS pain score and KOOS questionnaires preoperatively, and VAS pain, KOOS, and patient satisfaction 3, 12, and 72 months postoperatively. Physical performance tests were performed preoperatively and 3 months postoperatively. Results We found similar scores for VAS pain, patient satisfaction, and KOOS 5 subscales at 3, 12, and 72 months postoperatively in the 2 groups. Physical performance tests 3 months postoperatively were also similar in the 2 groups. No secondary resurfacing was performed in the group with no resurfacing during the first 72 months Interpretation Patellar resurfacing in primary Triathlon CR TKA is of no advantage regarding pain, physical performance, KOOS 5 subscales, or patient satisfaction compared to no resurfacing. None of the patients were reoperated with secondary addition of a patellar component within 6 years. According to these results, routine patellar resurfacing in primary Triathlon TKA appears to be unnecessary. PMID:27212102

Differences in tendon properties in elite badminton players with or without patellar tendinopathy.

PubMed

Couppé, C; Kongsgaard, M; Aagaard, P; Vinther, A; Boesen, M; Kjaer, M; Magnusson, S P

2013-03-01

The aim of this study was to examine the structural and mechanical properties of the patellar tendon in elite male badminton players with and without patellar tendinopathy. Seven players with unilateral patellar tendinopathy (PT group) on the lead extremity (used for forward lunge) and nine players with no current or previous patellar tendinopathy (CT group) were included. Magnetic resonance imaging was used to assess distal patellar tendon dimensions. Patellar tendon mechanical properties were assessed using simultaneous tendon force and deformation measurements. Distal tendon cross-sectional area (CSA) normalized for body weight (mm(2) /kg(2/3) ) was lower in the PT group compared with the CT group on both the non-lead extremity (6.1 ± 0.3 vs 7.4 ± 0.2, P < 0.05) and the lead extremity (6.5 ± 0.6 vs 8.4 ± 0.3, P < 0.05). Distal tendon stress was higher in the PT group compared with the CT group for both the non-lead extremity (31 ± 1 vs 27 ± 1 MPa, P < 0.05) and the lead extremity (32 ± 3 vs 21 ± 3 MPa, P < 0.01). Conclusively, the PT group had smaller distal patellar tendon CSA on both the injured (lead extremity) and the uninjured side (non-lead extremity) compared with the CT group. Subsequently, the smaller CSA yielded a greater distal patellar tendon stress in the PT group. Therefore, a small tendon CSA may predispose to the development of tendinopathy. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... degenerative and posttraumatic patellar arthritis. (2) Class III when intended for uses other than treatment of degenerative and posttraumatic patellar arthritis. (c) Date PMA or notice of completion of a PDP is required. A...

21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... degenerative and posttraumatic patellar arthritis. (2) Class III when intended for uses other than treatment of degenerative and posttraumatic patellar arthritis. (c) Date PMA or notice of completion of a PDP is required. A...

21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... degenerative and posttraumatic patellar arthritis. (2) Class III when intended for uses other than treatment of degenerative and posttraumatic patellar arthritis. (c) Date PMA or notice of completion of a PDP is required. A...

21 CFR 888.3580 - Knee joint patellar (hemi-knee) metallic resurfacing uncemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... degenerative and posttraumatic patellar arthritis. (2) Class III when intended for uses other than treatment of degenerative and posttraumatic patellar arthritis. (c) Date PMA or notice of completion of a PDP is required. A...

A soft patellar tendon on ultrasound elastography is associated with pain and functional deficit in volleyball players.

PubMed

Ooi, Chin Chin; Richards, Paula J; Maffulli, Nicola; Ede, David; Schneider, Michal E; Connell, David; Morrissey, Dylan; Malliaras, Peter

2016-05-01

To investigate the diagnostic performance of grey scale Ultrasound (US), power Doppler (PD) and US elastography for diagnosing painful patellar tendinopathy, and to establish their relationship with Victorian Institute of Sport Assessment-Patella (VISA-P) scores in a group of volleyball players with and without symptoms of patellar tendinopathy. Cross-sectional study. Thirty-five volleyball players (70 patellar tendons) were recruited during a national university volleyball competition. Players were imaged with conventional US followed by elastography. The clinical findings of painful patellar tendons were used as the reference standard for diagnosing patellar tendinopathy. In addition, all participants completed the VISA-P questionnaires. Of the 70 patellar tendons, 40 (57.1%) were clinically painful. The diagnostic accuracy of grey scale US, PD and elastography were 60%, 50%, 62.9%, respectively, with sensitivity/specificity of 72.5%/43.3%, 12.5%/100%, and 70%/53.3%, respectively. Combined US elastography and grey scale imaging achieved 82.5% sensitivity, 33.3% specificity and 61.4% accuracy while routine combination technique of PD and grey scale imaging revealed 72.5% sensitivity, 43.3% specificity and 60.0% accuracy. Tendons in players categorized as soft on elastography had statistically significantly greater AP thickness (p<0.001) and lower VISA-P scores (p=0.004) than those categorized as hard. There was no significant association between grey scale US abnormalities (hypoechogenicities and/or fusiform swelling) and VISA-P scores (p=0.098). Soft tendon properties depicted by US elastography may be more related to patellar tendon symptoms compared to grey scale US abnormalities. The supplementation of US elastography to conventional US may enhance the sensitivity for diagnosing patellar tendinopathy in routine clinical practice. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Effects of static stretching of knee musculature on patellar alignment and knee functional disability in male patients diagnosed with knee extension syndrome: A single-group, pretest-posttest trial.

PubMed

Pourahmadi, Mohammad Reza; Ebrahimi Takamjani, Ismail; Hesampour, Kazem; Shah-Hosseini, Gholam Reza; Jamshidi, Ali Ashraf; Shamsi, Mohammad Bagher

2016-04-01

Knee extension (Kext) syndrome is based on movement system impairments and is described as knee pain associated with quadriceps stiffness. To investigate the effects of 3 times per week for 4 weeks static stretching of knee musculature on patellar alignment and knee functional disability in male Kext syndrome patients. A single-group, pretest-posttest clinical trial. Hazrat-e-Rasoul Akram Hospital. Forty-six male Kext syndrome patients aged 18-35 years. Knee functional disability was assessed by the Kujala questionnaire. Patellar tilt was assessed using the skyline view X-ray. In addition, patella alta was assessed by X-ray using the Insall-Salvati ratio. After intervention, changes in knee flexion-extension range of motion (ROM) and hip adduction were assessed by goniometer and inclinometer. Changes in patellar tilt and patella alta were evaluated. Correlations between muscles length, patellar tilt and knee functional disability were also evaluated. The mean of patellar tilt in male Kext syndrome patients was 15.19°. Only the correlation between rectus femoris shortness and patellar tilt (P = 0.002) and the correlation between rectus femoris shortness and knee functional disability (P = 0.037) were significant. Patella alta was not severe in male Kext syndrome patients (1.28 ± 0.10). Knee flexion-extension ROM and femoral adduction increased significantly after a 12-session stretching programme (P < 0.0001). The results demonstrated that rectus femoris shortness had higher correlation with patellar tilt and knee functional disability than iliotibial band and hamstring shortness. Stretching was effective in reducing patellar tilt, patella alta, knee functional disability, increasing knee ROM and hip adduction in these patients. Copyright © 2015 Elsevier Ltd. All rights reserved.

Correction of Patellofemoral Malalignment With Patellofemoral Arthroplasty.

PubMed

Valoroso, Marco; Saffarini, Mo; La Barbera, Giuseppe; Toanen, Cécile; Hannink, Gerjon; Nover, Luca; Dejour, David H

2017-12-01

The goal of patellofemoral arthroplasty (PFA) is to replace damaged cartilage and correct underlying deformities to reduce pain and prevent maltracking. We aimed to determine how PFA modifies patellar height, tilt, and tibial tuberosity-trochlear groove (TT-TG) distance. The hypothesis was that PFA would correct trochlear dysplasia or extensor mechanism malalignment. The authors prospectively studied a series of 16 patients (13 women and 3 men) aged 64.9 ± 16.3 years (range 41-86 years) who received PFA. All knees were assessed preoperatively and 6 months postoperatively using frontal, lateral, and "skyline" x-rays, and computed tomography scans to calculate patellar tilt, patellar height, and TT-TG distance. The interobserver agreement was excellent for all parameters (intraclass correlation coefficient >0.95). Preoperatively, the median patellar tilt without quadriceps contraction (QC) was 17.5° (range 5.3°-33.4°) and with QC was 19.8° (range 0°-52.0°). The median Caton-Deschamps index was 0.91 (range 0.80-1.22) and TT-TG distance was 14.5 mm (range 4.0-22.0 mm). Postoperatively, the median patellar tilt without QC was 0.3° (range -15.3° to 9.5°) and with QC was 6.1° (range -11.5° to 13.3°). The median Caton-Deschamps index was 1.11 (range 0.81-1.20) and TT-TG distance was 10.1 mm (range 1.8-13.8 mm). The present study demonstrates that beyond replacing arthritic cartilage, trochlear-cutting PFA improves patellofemoral congruence by correcting trochlear dysplasia and standardizing radiological measurements as patellar tilt and TT-TG. The association of lateral patellar facetectomy improves patellar tracking by reducing the patellar tilt. Copyright © 2017 Elsevier Inc. All rights reserved.

[Neglected ipsilateral simultaneous ruptures of patellar and quadriceps tendon].

PubMed

Karahasanoğlu, İlker; Yoloğlu, Osman; Kerimoğlu, Servet; Turhan, Ahmet Uğur

2015-01-01

Neglected patellar and quadriceps tendon rupture is a rare injury, but ipsilateral simultaneous patellar and quadriceps tendon rupture was not described in the literature to our knowledge. In this article, we report a 40-year-old healthy male patient with neglected ipsilateral patellar and quadriceps tendon ruptures treated by peroneus longus tendon autograft. Patient had received some conservative and surgical treatments for patellar fracture before applying to our clinic. After our treatment using peroneus longus autograft and interference nails, patient was immobilized for six weeks in cylindrical cast. Flexion exercises and full weight bearing were started after cast removal. Patient had no complaint at postoperative second year. Patient was a neglected case. Surgical repair and early rehabilitation enabled us to achieve a satisfactory outcome.

Biomechanical study of patellofemoral joint instability

NASA Astrophysics Data System (ADS)

Senavongse, Wongwit

2005-04-01

Patellofemoral joint instability is a complex clinical problem. It may be a consequence of pre-existing anatomical abnormality or trauma. The objectives of this study were to use experimental mechanics to measure patellar stability and to quantify the effects of pathological abnormalities on patellar stability in vitro. Eight fresh-frozen cadaver knees were studies. The patellar stability was measured using an Instron material testing machine. A total load of 175N was applied to the quadriceps muscles. Patellar force-displacement was tested at different knee flexion angles as the patella was cyclically displaced 10mm laterally and medially. Three pathological abnormalities were applied; VMO malfunction, flat lateral trochlea, and medial retinacular structure rupturing. For the first time, this study has shown comparative and quantitative influence of pathological abnormalities on patellar stability. It was found that a flat lateral trochlea has greater effect than the medial retinacular rupturing whereas the medial retinacular rupturing has greater effect than VMO malfunction on patellar lateral stability. These results are important for future investigations on the treatment of patellofemoral instability.

Current concepts review: Fractures of the patella

PubMed Central

Gwinner, Clemens; Märdian, Sven; Schwabe, Philipp; Schaser, Klaus-D.; Krapohl, Björn Dirk; Jung, Tobias M.

2016-01-01

Fractures of the patella account for about 1% of all skeletal injuries and can lead to profound impairment due to its crucial function in the extensor mechanism of the knee. Diagnosis is based on the injury mechanism, physical examination and radiological findings. While the clinical diagnosis is often distinct, there are numerous treatment options available. The type of treatment as well as the optimum timing of surgical intervention depends on the underlying fracture type, the associated soft tissue damage, patient factors (i.e. age, bone quality, activity level and compliance) and the stability of the extensor mechanism. Regardless of the treatment method an early rehabilitation is recommended in order to avoid contractures of the knee joint capsule and cartilage degeneration. For non-displaced and dislocated non-comminuted transverse patellar fractures (2-part) modified anterior tension band wiring is the treatment of choice and can be combined – due to its biomechanical superiority – with cannulated screw fixation. In severe comminuted fractures, open reduction and fixation with small fragment screws or new angular stable plates for anatomic restoration of the retropatellar surface and extension mechanism results in best outcome. Additional circular cerclage wiring using either typical metal cerclage wires or resorbable PDS/non-resorbable FiberWires increases fixation stability and decreases risk for re-dislocation. Distal avulsion fractures should be fixed with small fragment screws and should be protected by a transtibial McLaughlin cerclage. Partial or complete patellectomy should be regarded only as a very rare salvage operation due to its severe functional impairment. PMID:26816667

Superior-inferior position of patellar component affects patellofemoral kinematics and contact forces in computer simulation.

PubMed

Nakamura, Shinichiro; Tanaka, Yoshihisa; Kuriyama, Shinichi; Nishitani, Kohei; Ito, Hiromu; Furu, Moritoshi; Matsuda, Shuichi

2017-06-01

Anterior knee pain has been reported as a major postoperative complication after total knee arthroplasty, which may lead to patient dissatisfaction. Rotational alignment and the medial-lateral position correlate with patellar maltracking, which can cause knee pain postoperatively. However, the superior-inferior position of the patellar component has not been investigated. The purpose of the current study was to investigate the effects of the patellar superior-inferior position on patellofemoral kinematics and kinetics. Superior, central, and inferior models with a dome patellar component were constructed. In the superior and inferior models, the position of the patellar component translated superiorly and inferiorly, respectively, by 3mm, relative to the center model. Kinematics of the patellar component, quadriceps force, and patellofemoral contact force were calculated using a computer simulation during a squatting activity in a weight-bearing deep knee bend. In the inferior model, the flexion angle, relative to the tibial component, was the greatest among all models. The inferior model showed an 18.0%, 36.5%, and 22.7% increase in the maximum quadriceps force, the maximum medial patellofemoral force, and the maximum lateral patellofemoral force, respectively, compared with the superior model. Superior-inferior positions affected patellofemoral kinematic and kinetics. Surgeons should avoid the inferior position of the patellar component, because the inferior positioned model showed greater quadriceps and patellofemoral force, resulting in a potential risk for anterior knee pain and component loosening. Copyright © 2017. Published by Elsevier Ltd.

Correlation of the tibial tuberosity-trochlear groove distance with the Q-angle.

PubMed

Dickschas, Jörg; Harrer, Jörg; Bayer, Thomas; Schwitulla, Judith; Strecker, Wolf

2016-03-01

The Q-angle has been used for years to quantify lateralization of the patella. The tibial tuberosity-trochlea groove distance (TT-TG distance) was introduced to analyse patellar tracking. Does a significant correlation exist between these two parameters? Do other significant interrelations exist between the Q-angle/TT-TG distance, torsion of the femur and tibia, the frontal axis, overall leg length, gender, former patellar dislocation, BMI? One hundred knees in 55 patients with patellofemoral symptoms were included in a prospective study. All patients underwent clinical examination, including measurement of the Q-angle. A torsional CT was obtained from all patients. The correlation coefficient was 0.33/0.34 (left/right leg), showing that the TT-TG distance tends to rise in direct ratio to a rising Q-angle. Thus, a significant correlation was found (p = 0.017). Femoral and tibial torsion had a positive effect on the TT-TG distance, but showed no significant correlation. Leg length had a significant effect on the TT-TG distance (p = 0.04). The frontal axis had a nonsignificant influence on the Q-angle or TT-TG distance. On average, the Q-angle in women was 2.38° greater than it was in men, but the difference was not significant. A significant correlation was noted between the Q-angle and the TT-TG distance. Both depend on various parameters and must be assessed for the analysis of patellofemoral maltracking. The Q-angle did not differ significantly between men and women; thus, the conclusion is that no different ranges need not be used. Diagnostic study, Level III.

Surface Area of Patellar Facets: Inferential Statistics in the Iraqi Population

PubMed Central

Al-Zamili, Zaid; Omar, Rawan

2017-01-01

Background. The patella is the largest sesamoid bone in the body; its three-dimensional complexity necessitates biomechanical perfection. Numerous pathologies occur at the patellofemoral unit which may end in degenerative changes. This study aims to test the presence of statistical correlation between the surface areas of patellar facets and other patellar morphometric parameters. Materials and Methods. Forty dry human patellae were studied. The morphometry of each patella was measured using a digital Vernier Caliper, electronic balance, and image analyses software known as ImageJ. The patellar facetal surface area was correlated with patellar weight, height, width, and thickness. Results. Inferential statistics proved the existence of linear correlation of total facetal surface area and patellar weight, height, width, and thickness. The correlation was strongest for surface area versus patellar weight. The lateral facetal area was found persistently larger than the medial facetal area, the p value was found to be <0.001 (one-tailed t-test) for right patellae, and another significant p value of < 0.001 (one-tailed t-test) was found for left patellae. Conclusion. These data are vital for the restoration of the normal biomechanics of the patellofemoral unit; these are to be consulted during knee surgeries and implant designs and can be of an indispensable anthropometric, interethnic, and biometric value. PMID:28348891

Transplantation of free tibial periosteal grafts for the repair of articular cartilage defect: An experimental study

PubMed Central

Singh, Ravijot; Chauhan, Vijendra; Chauhan, Neena; Sharma, Sansar

2009-01-01

Background: Articular chondrocytes have got a long lifespan but rarely divides after maturity. Thus, an articular cartilage has a limited capacity for repair. Periosteal grafts have chondrogenic potential and have been used to repair defects in the articular cartilage. The purpose of the present study is to investigate the differentiation of free periosteal grafts in the patellofemoral joint where the cambium layer faces the subchondral bone and to investigate the applicability of periosteal grafts in the reconstruction of articular surfaces. Materials and Methods: The study was carried out over a period of 1 year on 25 adult, male Indian rabbits after obtaining permission from the institutional animal ethical committee. A full-thickness osteochondral defect was created by shaving off the whole articular cartilage of the patella of the left knee. The defect thus created was grafted with free periosteal graft. The patella of the right knee was taken as a control where no grafting was done after shaving off the articular cartilage. The first animal was used to study the normal histology of the patellar articular cartilage and periosteum obtained from the medial surface of tibial condyle. Rest 24 animals were subjected to patellectomy, 4 each at serial intervals of 2, 4, 8, 16, 32 and 48 weeks and the patellar articular surfaces were examined macroscopically and histologically. Results: The grafts got adherent to the underlying patellar articular surface at the end of 4 weeks. Microscopically, graft incorporation could be appreciated at 4 weeks. Mesenchymal cells of the cambium layer were seen differentiating into chondrocytes by the end of 4 weeks in four grafts (100%) and they were arranged in a haphazard manner. Till the end of 8 weeks, the cellular arrangement was mostly wooly. At 16 weeks, one graft (25%) had wooly arrangement of chondrocytes and three grafts (75%) had columnar formation of cells. Same percentage was maintained at 32 weeks. Four grafts (100%) at 48 weeks showed columnar orientation. The control side showed no changes over the shaved off articular surface in all the rabbits. One rabbit at 4 weeks had a dislocation of the patella on the control side. None of the rabbits developed any infection or wound dehiscence. Conclusion: Autologous periosteal graft transplantation can be a promising substitute for articular cartilaginous defects. PMID:19838382

Effect of Implanting a Soft Tissue Autograft in a Central-Third Patellar Tendon Defect: Biomechanical and Histological Comparisons

PubMed Central

Kinneberg, Kirsten R. C.; Galloway, Marc T.; Butler, David L.; Shearn, Jason T.

2011-01-01

Previous studies by our laboratory have demonstrated that implanting a stiffer tissue engineered construct at surgery is positively correlated with repair tissue stiffness at 12 weeks. The objective of this study was to test this correlation by implanting a construct that matches normal tissue biomechanical properties. To do this, we utilized a soft tissue patellar tendon autograft to repair a central-third patellar tendon defect. Patellar tendon auto-graft repairs were contrasted against an unfilled defect repaired by natural healing (NH). We hypothesized that after 12 weeks, patellar tendon autograft repairs would have biomechanical properties superior to NH. Bilateral defects were established in the central-third patellar tendon of skeletally mature (one year old), female New Zealand White rabbits (n = 10). In one limb, the excised tissue, the patellar tendon autograft, was sutured into the defect site. In the contralateral limb, the defect was left empty (natural healing). After 12 weeks of recovery, the animals were euthanized and their limbs were dedicated to bio-mechanical (n = 7) or histological (n = 3) evaluations. Only stiffness was improved by treatment with patellar tendon autograft relative to natural healing (p = 0.009). Additionally, neither the patellar tendon autograft nor natural healing repairs regenerated a normal zonal insertion site between the tendon and bone. Immunohistochemical staining for collagen type II demonstrated that fibrocartilage-like tissue was regenerated at the tendon-bone interface for both repairs. However, the tissue was disorganized. Insufficient tissue integration at the tendon-to-bone junction led to repair tissue failure at the insertion site during testing. It is important to re-establish the tendon-to-bone insertion site because it provides joint stability and enables force transmission from muscle to tendon and subsequent loading of the tendon. Without loading, tendon mechanical properties deteriorate. Future studies by our laboratory will investigate potential strategies to improve patellar tendon autograft integration into bone using this model. [DOI: 10.1115/1.4004948] PMID:22010737

Relationship between patellar mobility and patellofemoral joint cartilage degeneration after anterior cruciate ligament reconstruction.

PubMed

Ota, Susumu; Kurokouchi, Kazutoshi; Takahashi, Shigeo; Yoda, Masaki; Yamamoto, Ryuichiro; Sakai, Tadahiro

2017-11-01

Patellofemoral cartilage degeneration is a potential complication of anterior cruciate ligament reconstruction (ACLR) surgery. Hypomobility of the patella in the coronal plane is often observed after ACLR. Few studies, however, have examined the relationship between cartilage degeneration in the patellofemoral joint and mobility after ACLR. The present study investigated 1) the coronal mobility of the patella after ACLR, 2) the relationship between patellar mobility and cartilage degeneration of the patellofemoral joint, and 3) the relationship between patellar mobility and knee joint function after ACLR. Forty patients who underwent medial hamstring-based ACLR participated in the study. Lateral and medial patellar displacements were assessed with a modified patellofemoral arthrometer, and the absolute values of the displacements were normalized to patient height. The International Cartilage Repair Society (ICRS) cartilage injury classification of the patellar and femoral (trochlear) surfaces, and the Lysholm Knee Scoring Scale were used to evaluate knee function. Lateral and medial patellar displacements were reduced compared with the non-operated knee at the second-look arthroscopy and bone staple extraction operation (second operation; 24.4 ± 7.9 months after ACLR, P<0.01). The ICRS grades of the patellofemoral joint (patella and trochlea) were significantly worse than those pre-ACLR. Neither lateral nor medial patellar mobility, however, were significantly correlated with the ICRS grade or the Lysholm score. Although patellar mobility at approximately 2 years after ACLR was decreased compared to the non-operated knee, small displacement of the patella was not related to cartilage degeneration or knee joint function at the time of the second operation.

Do Changes in Patellofemoral Joint Offset Lead to Adverse Outcomes in Total Knee Arthroplasty With Patellar Resurfacing? A Radiographic Review.

PubMed

Matz, Jacob; Howard, James L; Morden, David J; MacDonald, Steven J; Teeter, Matthew G; Lanting, Brent A

2017-03-01

Patellofemoral joint biomechanics contribute to anterior knee pain, instability, and dysfunction following total knee arthroplasty (TKA). Information about specific factors leading to anterior knee pain and dysfunction is currently limited. Changes in patellofemoral joint offset (PFO) refers to a mismatch between the preoperative and postoperative anteroposterior geometry of the patellofemoral joint. It remains unclear whether these changes lead to adverse outcomes in TKA. A retrospective radiographic review of 970 knees pre-TKA and post-TKA was completed to correlate the radiographic and clinical outcomes of changing the PFO using a posterior-stabilized single knee design with patellar resurfacing. A total of 970 patients were reviewed. Postoperatively, the anterior femoral offset, anteroposterior femoral size, and anterior patellar offset were changed in 40%, 60%, and 71% of knees, respectively, compared to preoperative values. The Western Ontario and McMasters Osteoarthritis Index total score as well as subscale scores for pain and function were not significantly affected by an increase or decrease in PFO. Similarly, Knee Society Scores and range of motion were not significantly affected. Increased anterior patellar offset was, however, associated with increased postoperative patellar tilt. Postoperative patellar tilt was not correlated with adverse patient satisfaction scores or loss of range of motion. Changes in PFO (decreased, maintained, or increased) are common post-TKA and are not associated with a difference in clinical outcomes. Increases in anterior patellar offset led to increased patellar tilt, which was not associated with adverse patient satisfaction scores. Copyright © 2016 Elsevier Inc. All rights reserved.

Decline eccentric squats increases patellar tendon loading compared to standard eccentric squats.

PubMed

Kongsgaard, M; Aagaard, P; Roikjaer, S; Olsen, D; Jensen, M; Langberg, H; Magnusson, S P

2006-08-01

Recent studies have shown excellent clinical results using eccentric squat training on a 25 degrees decline board to treat patellar tendinopathy. It remains unknown why therapeutic management of patellar tendinopathy using decline eccentric squats offer superior clinical efficacy compared to standard horizontal eccentric squats. This study aimed to compare electromyography activity, patellar tendon strain and joint angle kinematics during standard and decline eccentric squats. Thirteen subjects performed unilateral eccentric squats on flat-and a 25 degrees decline surface. During the squats, electromyography activity was obtained in eight representative muscles. Also, ankle, knee and hip joint goniometry was obtained. Additionally, patellar tendon strain was measured in vivo using ultrasonography as subjects maintained a unilateral isometric 90 degrees knee angle squat position on either flat or 25 degrees decline surface. Patellar tendon strain was significantly greater (P<0.05) during the squat position on the decline surface compared to the standard surface. The stop angles of the ankle and hip joints were significantly smaller during the decline compared to the standard squats (P<0.001, P<0.05). Normalized mean electromyography amplitudes of the knee extensor muscles were significantly greater during the decline compared to the standard squats (P<0.05). Hamstring and calf muscle mean electromyography did not differ, respectively, between standard and decline squats. The use of a 25 degrees decline board increases the load and the strain of the patellar tendon during unilateral eccentric squats. This finding likely explains previous reports of superior clinical efficacy of decline eccentric squats in the rehabilitative management of patellar tendinopathy.

Effect of patellar strap and sports tape on pain in patellar tendinopathy: A randomized controlled trial.

PubMed

de Vries, A; Zwerver, J; Diercks, R; Tak, I; van Berkel, S; van Cingel, R; van der Worp, H; van den Akker-Scheek, I

2016-10-01

Numerous athletes with patellar tendinopathy (PT) use a patellar strap or sports tape during sports. This study's aim was to investigate the short-term effect of these orthoses on patellar tendon pain. Participants performed the single-leg decline squat, vertical jump test, and triple-hop test under four different conditions (patellar strap, sports tape, placebo, and control). Subsequently, participants practiced sports as usual for 2 weeks; during 1 week, they were assigned to one of the four conditions. Pain was measured with the visual analog scale (VAS). In total, 97 athletes with PT [61% male, age 27.0 (SD8.1), VISA-P 58.5 (SD12.7)] were analyzed. On the single-leg decline squat, the VAS pain score reduced significantly in the patellar strap (14 mm, P = 0.04) and the sports tape condition (13 mm, P = 0.04), compared with control, but not placebo. A significant decrease in VAS pain during sports was found in the sports tape (7 mm, P = 0.04) and placebo group (6 mm, P = 0.04). The VAS pain score two hours after sports decreased significantly in the patellar strap, sports tape and placebo group (8-mm, P < 0.001, 10 mm, P = 0.001 and 7 mm, P = 0.03, respectively). This study's findings indicate that an orthosis (including placebo tape) during sports can reduce pain in PT patients in the short term. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Validity and reliability of the Dutch translation of the VISA-P questionnaire for patellar tendinopathy.

PubMed

Zwerver, Johannes; Kramer, Tamara; van den Akker-Scheek, Inge

2009-08-11

The VISA-P questionnaire evaluates severity of symptoms, knee function and ability to play sports in athletes with patellar tendinopathy. This English-language self-administered brief patient outcome score was developed in Australia to monitor rehabilitation and to evaluate outcome of clinical studies. Aim of this study was to translate the questionnaire into Dutch and to study the reliability and validity of the Dutch version of the VISA-P. The questionnaire was translated into Dutch according to internationally recommended guidelines. Test-retest reliability was determined in 99 students with a time interval of 2.5 weeks. To determine discriminative validity of the Dutch VISA-P, 18 healthy students, 15 competitive volleyball players (at-risk population), 14 patients with patellar tendinopathy, 6 patients who had surgery for patellar tendinopathy, 17 patients with knee injuries other than patellar tendinopathy, and 9 patients with symptoms unrelated to their knees completed the Dutch VISA-P. The Dutch VISA-P questionnaire showed satisfactory test-retest reliability (ICC=0.74). The mean (+/-SD) VISA-P scores were 95 (+/-9) for the healthy students, 89 (+/-11) for the volleyball players, 58 (+/-19) for patients with patellar tendinopathy, and 56 (+/-21) for athletes who had surgery for patellar tendinopathy. Patients with other knee injuries or symptoms unrelated to the knee scored 62 (+/-24) and 77 (+/-24). The translated Dutch version of the VISA-P questionnaire is equivalent to its original version, has satisfactory test-retest reliability and is a valid score to evaluate symptoms, knee function and ability to play sports of Dutch athletes with patellar tendinopathy.

The Effect of Electrocautery around the Patellar Rim in Patellar Non-Resurfacing Total Knee Arthroplasty

PubMed Central

Yim, Soo Jae; Jang, Mun Suk; Kim, Wook Joong; Kang, Hee Kyung

2012-01-01

Purpose The purpose of this study was to evaluate the clinical effect of electrocautery on the reduction of pain in patellar non-resurfacing bilateral total knee arthroplasty. Materials and Methods A total of 50 patients were enrolled into this study; all patients had undergone bilateral patellar non-resurfacing total knee arthoplasty at our hospital, between January 2007 to December 2008. The minimum follow-up period was 1 year. The electrocautery of the patellar rim was performed randomly on one side only. The clinical results were evaluated between the electrocautery group and the non-electrocautery group based on measures of anterior knee pain, range of motion, American Knee Society clinical rating score, Feller knee score, Western Ontario and McMaster Universities score, and radiographic analysis. Results There were statistically significant differences between preoperative and postoperative status for all parameters. There were no statistically significant differences noted between the electrocautery group and the non electrocautery group for all parameters. Conclusions Electrocautery of patellar rim is thought to be less effective in reducing anterior knee pain. PMID:22708111

Patellar fixation protected with a load-sharing cable: a mechanical and clinical study.

PubMed

Perry, C R; McCarthy, J A; Kain, C C; Pearson, R L

1988-01-01

The stability of patellar fracture fixation protected with a load-sharing cable was studied in cadavers. A transverse patellar osteotomy was produced and stabilized with standard patellar fixation with or without a figure-of-eight cable that extends from the proximal pole of the patella to the tibial tubercle. Standard fixation techniques (interfragmentary cancellous screws or modified tension-band wiring) alone failed after significantly fewer cycles of flexion and extension than did the same fixation when supplemented with a load-sharing cable. In the clinical evaluation of the load-sharing cable, 14 consecutive patients with displaced patellar fractures were treated. No immobilization was used and the patients were started on passive and active range of motion and weight-bearing ambulation in the early postoperative period. Thirteen fractures healed uneventfully. The increased stability of patellar fracture fixation protected with a load-sharing cable offers three advantages: (a) adjunctive casting is unnecessary, (b) comminuted fractures can be "pieced" together anatomically with less concern for loss of fixation, and (c) early postoperative passive and active range of motion can be achieved.

Use of platelet-rich plasma for patellar tendon and medial collateral ligament injuries: best current clinical practice.

PubMed

Andia, Isabel; Maffulli, Nicola

2015-02-01

Platelet-rich plasmas (PRPs) are complex molecular therapies prepared from the patient's own blood through minimal manipulation. Clinical studies examining the efficacy of PRPs to manage patellar tendinopathy and medial collateral ligament (MCL) injuries have been reviewed. We found three controlled trials, two of them randomized, and seven case series in the management of patellar tendinopathy. In addition, three other randomized studies showed that PRPs help to regenerate the patellar tendon harvest site for anterior cruciate ligament reconstruction and to reduce patellar donor site morbidity. On the other hand, the use of PRP in MCL injuries is reported in a single case study. Seven of the 11 studies used leukocyte and PRP which was buffered in four studies. Seven of the 11 studies applied two or three injections. Given the heterogeneity of PRP protocols and the paucity of high-quality data, the most effective approach to guide clinical decisions regarding patellar tendinopathy cannot be deduced from the present published studies. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Evaluation of anterior knee pain in a PS total knee arthroplasty: the role of patella-friendly femoral component and patellar size.

PubMed

Atzori, F; Sabatini, L; Deledda, D; Schirò, M; Lo Baido, R; Baido, R L; Massè, A

2015-04-01

Total knee arthroplasty gives excellent objective results. Nevertheless, the subjective findings do not match the normal knee perception: Often, it depends on patellar pain onset. In this study, we analyzed clinical and radiological items that can affect resurfaced patellar tracking, and role of a patella-friendly femoral component and patellar size on patellar pain onset. Thirty consecutive patients were implanted using the same-cemented posterior-stabilized TKA associated with patella resurfacing. Fifteen patients were implanted using a classical femoral component, while another 15 patients were implanted using a patella-friendly femoral component. The statistical analysis was set to detect a significant difference (p < 0.05) in clinical and radiological outcomes related to several surgical parameters. Clinical and functional outcomes were recorded using the Knee Society Scoring System (KSS) and patellar pain with the Burnett questionnaire. Mean follow-up was 25 months. KSS results were excellent in both groups. Group 2 (patella-friendly femoral model) reached a higher percentage of 100 points in the clinical and functional KSS, but there was no statistical difference. Also, no statistical differences for Burnett Questionnaire results were recorded. We had one case of patellar clunk syndrome in the standard femoral component group and one poor result in the second group. Postoperative radiographic measurements evidenced no statistical differences in both groups. In group 1 (classical femoral component), better significant result (p < 0.05) war recorded at clinical evaluation according to the Knee Society Scoring System (KSS) in case of wider patellar component resurfaced. The present study reveals no statistically significant difference in the incidence of anterior knee pain between classical and "patella-friendly" femoral components. With the particular type of implant design utilized in this study, when the classical femoral component is used, bigger patellar implant sizes (38 and 41 mm) showed superior clinical outcome.

Previously identified patellar tendinopathy risk factors differ between elite and sub-elite volleyball players.

PubMed

Janssen, I; Steele, J R; Munro, B J; Brown, N A T

2015-06-01

Patellar tendinopathy is the most common knee injury incurred in volleyball, with its prevalence in elite athletes more than three times that of their sub-elite counterparts. The purpose of this study was to determine whether patellar tendinopathy risk factors differed between elite and sub-elite male volleyball players. Nine elite and nine sub-elite male volleyball players performed a lateral stop-jump block movement. Maximum vertical jump, training history, muscle extensibility and strength, three-dimensional landing kinematics (250 Hz), along with lower limb neuromuscular activation patterns (1500 Hz), and patellar tendon loading were collected during each trial. Multivariate analyses of variance (P < 0.05) assessed for between-group differences in risk factors or patellar tendon loading. Significant interaction effects were further evaluated using post-hoc univariate analysis of variance tests. Landing kinematics, neuromuscular activation patterns, patellar tendon loading, and most of the previously identified risk factors did not differ between the elite and sub-elite players. However, elite players participated in a higher training volume and had less quadriceps extensibility than sub-elite players. Therefore, high training volume is likely the primary contributor to the injury discrepancy between elite and sub-elite volleyball players. Interventions designed to reduce landing frequency and improve quadriceps extensibility are recommended to reduce patellar tendinopathy prevalence in volleyball players. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Knee joint effusion following ipsilateral hip surgery.

PubMed

Christodoulou, A G; Givissis, P; Antonarakos, P D; Petsatodis, G E; Hatzokos, I; Pournaras, J D

2010-12-01

To correlate patellar reflex inhibition with sympathetic knee joint effusion. 65 women and 40 men aged 45 to 75 (mean, 65) years underwent hip surgery. The surgery entailed dynamic hip screw fixation using the lateral approach with reflection of the vastus lateralis for pertrochantric fractures (n = 49), and hip hemiarthroplasty or total hip replacement using the Watson-Jones approach (n = 38) or hip hemiarthroplasty using the posterior approach (n = 18) for subcapital femoral fractures (n = 28) or osteoarthritis (n = 28). Knee joint effusion, patellar reflex, and thigh circumference were assessed in both legs before and after surgery (at day 0.5, 2, 7, 14, 30, and 45). Time-sequence plots were used for chronological analysis, and correlation between patellar reflex inhibition and knee joint effusion was tested. In the time-sequence plot, the peak frequency of patellar reflex inhibition (on day 0.5) preceded that of the knee joint effusion and the thigh circumference increase (on day 2). Patellar reflex inhibition correlated positively with the knee joint effusion (r = 0.843, p = 0.035). These 2 factors correlated significantly for all 3 surgical approaches (p < 0.0005). All 3 approaches were associated with patellar reflex inhibition on day 0.5 (p = 0.033) and knee joint effusion on day 2 (p = 0.051). Surgical trauma of the thigh may cause patellar reflex inhibition and subsequently knee joint effusion.

Sonoelastographic Features of the Patellar Ligament in Clinically Normal Dogs.

PubMed

Piccionello, Angela P; Serrani, Daniele; Busoni, Valeria; Salvaggio, Alberto; Bonazzi, Mattia; Bergamino, Chiara; Volta, Antonella

2018-06-11

 This article describes the sonoelastographic features of the patellar ligament of sound dogs and tests feasibility, reproducibility and repeatability.  Clinically healthy medium-to-large breed dogs were enrolled. Sonoelastographic images of the patellar ligaments were obtained in lateral recumbency with the stifle flexed by an experienced operator and by a senior veterinary student. The elasticity colour map included red (soft), green (intermediate) and blue (hard). Tissue elasticity was measured by calculating the percentage of softness with dedicated software. Categorical, qualitative data analysis was performed using a weighted kappa statistic for repeatability and reproducibility. A categorical qualitative assessment was performed based on a grading scale of 1 to 5 (soft, mostly soft, intermediate, mostly hard and hard).  Fourteen clinically normal dogs were considered. A total of 28 patellar ligaments were examined. Overall, 25 of the patellar ligaments were graded as soft or mostly soft and the remaining 3 as intermediate. Repeatability was 86.2%, with a weighted kappa of 0.64 (good), for the well-trained sonographer and 83.3%, with a weighted kappa of 0.53 (moderate), for the senior student. Reproducibility was 86.2%, with a weighed kappa of 0.65 (good).  Sonoelastography of the canine patellar ligament is a feasible and reproducible technique. Patellar ligaments in clinically normal dogs showed highly elastic biomechanical properties. Schattauer GmbH Stuttgart.

High volume ultrasound guided injections at the interface between the patellar tendon and Hoffa's body are effective in chronic patellar tendinopathy: A pilot study.

PubMed

Crisp, Tom; Khan, Faisal; Padhiar, Nat; Morrissey, Dylan; King, John; Jalan, Rosy; Maffulli, Nicola; Frcr, Otto Chan

2008-01-01

To evaluate a novel conservative management modality for patellar tendinopathy. We recruited nine patients with patellar tendinopathy who had failed conservative management and showed evidence of neovascularisation on power Doppler scanning. A high volume ultrasound guided injection at the interface between the patellar tendon and Hoffa's body. The injection contained 10 ml 0.5% Bupivacaine, 25 mg Hydrocortisone, and between 12 and 40 ml normosaline. 100 mm visual analogue scales (VAS) for pain and for function, and Victorian Institute of Sport Assessment - Patellar tendon (VISA-P) questionnaires at an average of 9 months from the injection. All but one patient (whose pain was unchanged) improved (p = 0.028). The mean improvement in function 2 weeks after injection was 58 mm on VAS (interquartile range 27 - 88, p = 0.018). The mean improvement in pain 2 weeks after injection was 56 mm on a VAS scale (interquartile range 32 - 80, p = 0.018). At a mean follow up of 9 months, an improvement of 22 points from a baseline score of 46 on the VISA-P questionnaire (100 being normal) was established. High volume injections to mechanically disrupt the neovascularisation in patellar tendinopathy are helpful in the management of this condition. Controlled trials would be warranted to investigate in a more conclusive fashion this management modality.

Greater glycosaminoglycan content in human patellar tendon biopsies is associated with more pain and a lower VISA score.

PubMed

Attia, Mohamed; Scott, Alexander; Carpentier, Gilles; Lian, Oystein; Van Kuppevelt, Toin; Gossard, Camille; Papy-Garcia, Dulce; Tassoni, Marie-Claude; Martelly, Isabelle

2014-03-01

People with patellar tendinopathy experience chronic pain and activity limitation, but a pertinent biochemical marker correlated with these clinical features has not been identified. The Victoria Institute of Sport Assessment (VISA) questionnaire is a condition-specific patient-rated outcome measure. Since the quantity of glycosaminoglycans (GAGs) increases with advancing tendon pathology, we hypothesised that there would be a correlation between the quantity of GAGs in the patellar tendon and the VISA score. Tissue biopsies from athletes with chronic patellar tendinopathy (confirmed by clinical examination and MRI) were recruited (n=7), as well as controls with no history of knee pain (n=4). The quantity of sulphated GAGs in the human patellar tendons was determined with a dimethyl methylene blue (DMMB) assay; this method was first validated with rat tendon tissue. The extent and distribution of GAG species and proteoglycans (decorin, versican and aggrecan) in the human tendon biopsies were examined using immunohistochemistry. Greater sulphated GAG content of the patellar tendon was correlated with the greater tendon dysfunction (R(2)=0.798). The quantity of aggrecan in the tendon, a chondroitin sulphate-rich proteoglycan, also increased with advancing tendon pathology. Increased GAGs in the pathological human patellar tendon are related to a worse clinical status. These findings indicate that the VISA score reflects the extent of tendon tissue pathology.

Distal tibial tuberosity translation using TTA implants for the treatment of patella alta in large breed dogs. Surgical technique and clinical outcome.

PubMed

Pugliese, L C; Pike, F S; Aiken, S W

2015-01-01

Medial patellar luxation frequently occurs in dogs resulting in lameness with increasing incidence in large breed dogs. Patella alta has been defined as a patellar ligament length to patellar length ratio that is greater than two and may predispose to patellar luxation. To describe the surgical technique for stabilization of the distal translation of the tibial tuberosity using tibial tuberosity advancement plates and the clinical outcomes with follow-up for clinical cases of dogs. Dogs that were presented with the complaint of patellar luxation and that were concurrently diagnosed with patella alta and were greater than 20 kg in body weight underwent surgery using a tibial tuberosity advancement plate to stabilize the osteotomy. Radiographic assessment of A:PL distance (the ratio of the proximal aspect of the patella to the femoral condyle [A] to the patellar length [PL]), L:P ratio (ratio of the length of the patellar ligament to the diagonal length of the patella), and owner assessment were obtained. Eleven stifles in nine dogs underwent surgical correction with a mean preoperative L:P ratio of 2.47. There were no complications and the lameness resolved clinically. The mean A:PL ratios preoperatively (2.6 ± 0.22) and postoperatively (2.1 ± 0.25) were significantly different (p = 0.0003). All owners were satisfied with the outcome and all dogs had a resolution of lameness with no recurrence of patellar luxation. Stabilization of distal translation of the tibial tuberosity using tibial tuberosity advancement implants to correct patella alta in large breed dogs was feasible and resulted in good clinical outcome.

Achilles and patellar tendinopathy display opposite changes in elastic properties: A shear wave elastography study.

PubMed

Coombes, B K; Tucker, K; Vicenzino, B; Vuvan, V; Mellor, R; Heales, L; Nordez, A; Hug, F

2018-03-01

To compare tendon elastic and structural properties of healthy individuals with those with Achilles or patellar tendinopathy. Sixty-seven participants (22 Achilles tendinopathy, 17 patellar tendinopathy, and 28 healthy controls) were recruited between March 2015 and March 2016. Shear wave velocity (SWV), an index of tissue elastic modulus, and tendon thickness were measured bilaterally at mid-tendon and insertional regions of Achilles and patellar tendons by an examiner blinded to group. Analysis of covariance, adjusted for age, body mass index, and sex was used to compare differences in tendon thickness and SWV between the two tendinopathy groups (relative to controls) and regions. Tendon thickness was included as a covariate for analysis of SWV. Compared to controls, participants with Achilles tendinopathy had lower SWV at the distal insertion (Mean difference MD; 95% CI: -1.56; -2.49 to -0.62 m/s; P < .001) and greater thickness at the mid-tendon (MD 0.19; 0.05-0.33 cm; P = .007). Compared to controls, participants with patellar tendinopathy had higher SWV at both regions (MD 1.25; 0.40-2.10 m/s; P = .005) and greater thickness proximally (MD 0.17; 0.06-0.29 cm; P = .003). Compared to controls, participants with Achilles and patellar tendinopathy displayed lower Achilles tendon elastic modulus and higher patellar tendon elastic modulus, respectively. More research is needed to explore whether maturation, aging, or chronic load underlie these findings and whether current management programs for Achilles and patellar tendinopathy need to be tailored to the tendon. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The immediate effect of patellar tendon strap on weight-bearing asymmetry during squatting in patients with unilateral knee osteoarthritis: A pilot study.

PubMed

Demirbüken, İlkşan; Özyürek, Seher; Angın, Salih

2016-12-01

Knee osteoarthritis has commonly been associated with a symptom of pain resulting in an inter-limb weight-bearing asymmetry during functional tasks. Patellar tendon strap is one of the non-pharmacologic interventions to alleviate knee pain. To investigate the immediate effect of a patellar tendon strap on weight-bearing asymmetry during squatting in people with unilateral knee osteoarthritis. Cross-sectional study. Ten patients with unilateral knee osteoarthritis and 10 healthy subjects were included in the study. Weight-bearing asymmetry of patients was assessed using a weight-bearing squat test during squatting at 30° and 60° both with and without patellar tendon strap. Pain intensity was assessed during squatting in unstrapped and strapped conditions with Visual Analog Scale. The decrease in weight-bearing asymmetry values immediately after wearing patellar tendon strap during 30° (p = 0.006) and 60° (p = 0.011) of squatting tests was significantly higher in knee osteoarthritis patients than in healthy subjects. Reported pain intensity was similar in unstrapped and strapped conditions (p = 0.066). The results of this study showed improved inter-limb weight-bearing symmetry during squatting. Further research with larger sample sizes investigating the effect of patellar tendon strap on weight-bearing asymmetry during functional activities in people with knee osteoarthritis is warranted. Patellar tendon straps (easily fit and cheap unlike knee braces) had more improvements in inter-limb weight-bearing symmetry during squatting in people with knee osteoarthritis compared to healthy subjects. This study is a new insight for future studies to investigate clinical benefits of wearing patellar tendon straps in this population. © The International Society for Prosthetics and Orthotics 2015.

Bilateral patellar tuberculosis masquerading as infected infrapatellar bursitis.

PubMed

Sreenivasan, Ravi; Haq, Rehan Ul

2017-04-01

A 30-year-old woman presented to our outpatient department with complaints of pain and swelling in bilateral infrapatellar regions and a discharging sinus in the right knee over the duration of one year. Radiographs showed lytic regions in bilateral patellae. Samples sent from material curetted from sinus yielded no organism but histopathology reported granulomatous inflammation. Following a fresh magnetic resonance imaging (MRI) scan that revealed the infrapatellar pad of fat communicating with the patellar lesions, an exploration and evacuation was done. Material sent revealed epithelioid cell granulomas with caseous necrosis consistent with tuberculosis (TB). The patient was put on first line anti-tubercular treatment (ATT) and has responded favourably with healing of sinus and patellar lesions. Bilateral infrapatellar bursitis is not rare. However patellar TB as a cause for OMIT is not a common diagnosis. A bilateral patellar involvement has not been reported in literature to the best of our knowledge.

Radiographic Features of Acute Patellar Tendon Rupture.

PubMed

Fazal, Muhammad Ali; Moonot, Pradeep; Haddad, Fares

2015-11-01

The purpose of our study was to assess soft tissue features of acute patellar tendon rupture on lateral knee radiograph that would facilitate early diagnosis. The participants were divided into two groups of 35 patients each. There were 28 men and seven women with a mean age of 46 years in the control group and 26 men and nine women with a mean age of 47 years in the rupture group. The lateral knee radiograph of each patient was evaluated for Insall-Salvati ratio for patella alta, increased density of the infrapatellar fat pad, appearance of the soft tissue margin of the patellar tendon and bony avulsions. In the rupture group there were three consistent soft tissue radiographic features in addition to patellar alta. These were increased density of infrapatellar fat pad; loss of sharp, well-defined linear margins of the patellar tendon and angulated wavy margin of the patellar tendon while in the control group these features were not observed. The soft tissue radiographic features described in the rupture group are consistent and reliable. When coupled with careful clinical assessment, these will aid in early diagnosis and further imaging will be seldom required. © 2015 Chinese Orthopaedic Association and Wiley Publishing Asia Pty Ltd.

Does the adolescent patellar tendon respond to 5 days of cumulative load during a volleyball tournament?

PubMed

van Ark, M; Docking, S I; van den Akker-Scheek, I; Rudavsky, A; Rio, E; Zwerver, J; Cook, J L

2016-02-01

Patellar tendinopathy (jumper's knee) has a high prevalence in jumping athletes. Excessive load on the patellar tendon through high volumes of training and competition is an important risk factor. Structural changes in the tendon are related to a higher risk of developing patellar tendinopathy. The critical tendon load that affects tendon structure is unknown. The aim of this study was to investigate patellar tendon structure on each day of a 5-day volleyball tournament in an adolescent population (16-18 years). The right patellar tendon of 41 players in the Australian Volleyball Schools Cup was scanned with ultrasound tissue characterization (UTC) on every day of the tournament (Monday to Friday). UTC can quantify structure of a tendon into four echo types based on the stability of the echo pattern. Generalized estimating equations (GEE) were used to test for change of echo type I and II over the tournament days. Participants played between eight and nine matches during the tournament. GEE analysis showed no significant change of echo type percentages of echo type I (Wald chi-square = 4.603, d.f. = 4, P = 0.331) and echo type II (Wald chi-square = 6.070, d.f. = 4, P = 0.194) over time. This study shows that patellar tendon structure of 16-18-year-old volleyball players is not affected during 5 days of cumulative loading during a volleyball tournament. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

In Vivo Patellar Tracking and Patellofemoral Cartilage Contacts during Dynamic Stair Ascending

PubMed Central

Suzuki, Takashi; Hosseini, Ali; Li, Jing-Sheng; Gill, Thomas J; Li, Guoan

2012-01-01

The knowledge of normal patellar tracking is essential for understanding of the knee joint function and for diagnosis of patellar instabilities. This paper investigated the patellar tracking and patellofemoral joint contact locations during a stair ascending activity using a validated dual-fluoroscopic imaging system. The results showed that the patellar flexion angle decreased from 41.9° to 7.5° with the knee extension during stair ascending. During first 80% of the activity, the patella shifted medially about 3.9 mm and then slightly shifted laterally during the last 20% of the ascending activity. Anterior translation of 13 mm of the patella was measured at the early 80% of the activity and then slightly moved posteriorly by about 2 mm at the last 20% of the activity. The path of the cartilage contact points was slightly lateral on the cartilage surfaces of patella and femur. On the patellar cartilage surface, the cartilage contact locations were about 2 mm laterally from heel strike to 60% of the stair ascending activity and moved laterally and reached 5.3 mm at full extension. However, the cartilage contact locations were relatively constant on the femoral cartilage surface (~5 mm lateral). The patellar tracking pattern was consistent with the patellofemoral cartilage contact location pattern. These data could provide baseline knowledge for understanding of normal physiology of the patellofemoral joint and can be used as a reference for clinical evaluation of patellofemoral disorder symptoms. PMID:22840488

The Effect of Diacutaneous Fibrolysis on Patellar Position Measured Using Ultrasound Scanning in Patellofemoral Pain Syndrome Patients.

PubMed

Fanlo-Mazas, Pablo; Bueno-Gracia, Elena; de Escudero-Zapico, Alazne Ruiz; Tricás-Moreno, José Miguel; Lucha-López, María Orosia

2018-04-13

Tightness or lack of flexibility of flexibility of several muscles of the thigh has been associated with patellofemoral-join pain. A tight iliotibial band can lead to laterally located patella and an abnormal patellar tracking pattern. Diacutaneous fibrolysis is commonly used to reduce muscle tightness, but no studies have evaluated the effects of this technique in the treatment of patellofemoral pain syndrome patients. To assess the effect of diacutaneous fibrolysis on patellar position in patients with patellofemoral pain syndrome. A single-group, pretest-posttest clinical trial. University of Zaragoza. 46 subjects with patellofemoral pain (20 males, 26 females (age 27.8 ± 6.9 years)). 3 sessions of diacutaneous fibrolysis. Patellar position measurement using real time ultrasound scanning, pain intensity measured with visual analogue scale and function measured with the Anterior Knee Pain Scale. The application of three sessions of diacutaneous fibrolysis significantly increased the patellar position at post-treatment evaluation (p<0.001) and at one-week follow-up (p<0.001). There was not a significance difference on patellar position between post-treatment and follow-up measurements (p=0.283). There were also a statistically significant decrease in pain and increase in function at post-treatment and at one-week follow-up measurements (p<0.001). This study found that patellar position, pain intensity and function were significantly improved after three sessions of diacutaneous fibrolysis and at one week follow up.

Reliability and Validity of the Korean Version VISA-P Questionnaire for Patellar Tendinopathy in Adolescent Elite Volleyball Athletes.

PubMed

Park, Byung-Hyun; Seo, Jeong-Hwan; Ko, Myoung-Hwan; Park, Sung-Hee

2013-10-01

To translate the English Victorian Institute of Sport Assessment for patellar tendinopathy (VISA-P) questionnaire into a Korean version and to determine the reliability and validity of the Korean version. The English VISA-P questionnaire was translated into Korean according to the internationally recommended guidelines. Then, 28 adolescent elite volleyball athletes (average age, 16 years; range, 14 to 19 years) were asked to complete the questionnaire three times (before examination, after examination, and 1 week later) for reliability. They were evaluated through a physical examination and ultrasonography to diagnosis patellar tendinopathy. The internal consistency of the VISA-P questionnaire by Cronbach's alpha was 0.80 for the first, 0.78 for the second, and 0.79 for the third assessment. The intraclass correlation coefficient (ICC) between the first and second assessments was 0.97. The ICC between the second and third assessments was 0.96. The mean VISA-P scores were 67.6±15.7 for the patellar tendinopathy group (n=23) and 92.6±8.6 for the normal group (n=5). There were significantly lower VISA-P scores in the patellar tendinopathy group compared to the normal group. The translated Korean version VISA-P questionnaire has good internal consistency, test-retest reliability and validity. In addition, this study indicated that most adolescent elite volleyball athletes had patellar tendon problems. Therefore, the Korean version VISA-P is a useful self-administered outcome score of athletes with patellar tendinopathy.

In vitro kinematic measurements of the patellar tendon in two different types of posterior-stabilized total knee arthroplasties.

PubMed

Zhu, Zhonglin; Ding, Hui; Dang, Xiao; Tang, Jing; Zhou, Yixin; Wang, Guangzhi

2010-01-01

Fixed-bearing posterior-stabilized (PS) total knee arthroplasty (TKA) has been used in Asian countries for several years, but few studies have investigated differences in the kinematic properties of the patellar tendon after standard PS TKA as compared to high-flex PS TKA. To quantify the in vitro three-dimensional (3D) kinematics of the patellar tendon during passive high flexion and full extension before and after two different types of PS TKAs. Six fresh-frozen cadaveric knees were tested under the following conditions: the unaltered state, status-post traditional PS prostheses (Simth-nephew GENESIS II) replacement, and status-post high-flexion PS prostheses replacement. The soft tissue around the knee and the quadriceps muscle were preserved, then tested under the load of a specific weight in an Oxford knee rig. We designed a specialized rigid body with four active markers fixed to each bone to track the 3D passive motion of the cadaveric knees. Flexion and extension was controlled by the knee rig and captured by an Optotrak Certus high precision optical tracking system. The attachment sites of the patellar tendon were registered as virtual markers to calculate the 3D kinematics. The patellar tendon of the unaltered knee and both TKA knees showed similar deformation. We found the length of the patellar tendon changed significantly during a motion from full extension to 30°, but there was no significant change in length while undergoing a motion from 30° to full flexion. Both the sagittal plane and coronal plane angles of the patellar tendon decreased after PS TKAs. There was no significant difference in patellar tendon kinematics between the two types of PS TKAs. We believe the changes observed in the sagittal plane and coronal plane angles of the patellar tendon after PS TKAs may influence the extensor mechanism and be an important cause of patella-femoral complications. These data may be used to assess patella-femoral complications after surgery so as to improve the design of high-flexion TKAs for Asians and achieve long-term stability.

Operative Management of Patellar Instability in the United States: An Evaluation of National Practice Patterns, Surgical Trends, and Complications.

PubMed

Arshi, Armin; Cohen, Jeremiah R; Wang, Jeffrey C; Hame, Sharon L; McAllister, David R; Jones, Kristofer J

2016-08-01

Treatment of patellofemoral instability has evolved as our understanding of the relevant pathoanatomy has improved. In light of these developments, current practice patterns and management trends have likely changed to reflect these advancements; however, this has not been evaluated in a formal study. To determine nationwide patient demographics, surgical trends, and postoperative complications associated with the operative management of patellar instability surgery. Descriptive epidemiological study. A large private-payer database (PearlDiver) comprising patients covered by Humana and United Healthcare insurance policies was retrospectively reviewed using Current Procedural Terminology (CPT) codes to identify patients who underwent surgery for patellar instability. The study cohort was established by querying for patients billed under CPT codes 27420, 27422, or 27427 while satisfying the diagnostic requirement of patellar instability (International Classification of Diseases-9th Revision codes 718.36, 718.86, or 836.3). Patient demographics, surgical trends, concomitant procedures, and postoperative complications were determined. A total of 6190 patients underwent surgical management for patellar instability. Adolescents (age range, 10-19 years) represented 51.5% of cases, and 59.6% were female. The number of patellar instability procedures increased annually over the study period in both the Humana (P = .004, R (2) = 0.76) and United Healthcare (P = .097, R (2) = 0.54) cohorts. The most common concomitant procedures were lateral retinacular release (43.7%), chondroplasty (31.1%), tibial tubercle osteotomy (13.1%), removal of loose bodies (10.5%), osteochondral grafting (9.5%), and microfracture surgery (9.5%). Manipulation under anesthesia was required in 4.6% of patients within 1 year. Patellar fracture within 1 year and infection within 30 days occurred in 2.1% and 1.2% of patients, respectively. Patellar instability surgery has increased over the past decade. This finding may be attributed to growing clinical evidence to support these procedures as well as increased surgeon familiarity and comfort with these specific techniques. We observed an unexpectedly high rate of concomitant lateral retinacular release. Overall, the rates of commonly recognized complications (stiffness, patellar fracture, and postoperative infection) were similar to those observed in smaller case series.

Prophylactic training in asymptomatic soccer players with ultrasonographic abnormalities in Achilles and patellar tendons: the Danish Super League Study.

PubMed

Fredberg, Ulrich; Bolvig, Lars; Andersen, Niels T

2008-03-01

A recent study published in The American Journal of Sports Medicine showed that asymptomatic soccer players with an increased risk of developing Achilles and patellar tendon injuries within the next 12 months can be identified with use of ultrasonography. Prophylactic eccentric training and stretching can reduce both the frequency of asymptomatic ultrasonographic changes in Achilles and patellar tendons in soccer players and the risk of these asymptomatic intratendinous changes becoming symptomatic. Randomized controlled trial; Level of evidence, 1. Two hundred and nine Danish professional soccer players from the best national league (Super League) were followed over 12 months with use of ultrasonography and injury registration. Half the teams were randomized to an intervention group with prophylactic eccentric training and stretching of the Achilles and patellar tendons during the soccer season. The eccentric training and stretching did not reduce the injury risk, and, contrary to all expectations, the injury risk during the season was increased in players with abnormal patellar tendons at the beginning of the study in January. Eccentric training and stretching in players with normal patellar tendons significantly reduced the proportion of players with ultrasonographic changes in the patellar tendons at the end of the season (risk difference [RD] = 12%; 95% confidence interval [CI], 2%-22%; P = .02), but the training had no effect on the Achilles tendons (RD = 1%; 95% CI, -7% to 9%; P = .75). The presence of preseason ultrasonographic abnormalities in the tendons significantly increased the risk of developing tendon symptoms during the season (relative risk = 1.9; 95% CI, 1.2-3.1; P = .009). This study demonstrates that with the use of ultrasonography, tendon changes in soccer players can be diagnosed before they become symptomatic. The prophylactic eccentric training and stretching program reduces the risk of developing ultrasonographic abnormalities in the patellar tendons but has no positive effects on the risk of injury. On the contrary, in asymptomatic players with ultrasonographically abnormal patellar tendons, prophylactic eccentric training and stretching increased the injury risk.

Longitudinal change in patellofemoral cartilage thickness, cartilage T2 relaxation times, and subchondral bone plate area in adolescent vs mature athletes.

PubMed

Culvenor, Adam G; Wirth, Wolfgang; Maschek, Susanne; Boeth, Heide; Diederichs, Gerd; Duda, Georg; Eckstein, Felix

2017-07-01

Patellofemoral cartilage changes have been evaluated in knee trauma and osteoarthritis; however, little is known about changes in patellar and trochlear cartilage thickness, T2 relaxation-time and subchondral bone plate area (tAB) during growth. Our prospective study aimed to explore longitudinal change in patellofemoral cartilage thickness, T2 and tAB in adolescent athletes, and to compare these data with those of mature (i.e., adult) athletes. 20 adolescent (age 16±1years) and 20 mature (46±5years) volleyball players were studied over 2-years (10 men and 10 women each group). 1.5T MRI 3D-VIBE and multi-echo spin-echo sequences were acquired at baseline and 2-year follow-up. Using manual segmentation and 3D reconstruction, longitudinal changes in patellar and trochlear cartilage thickness, patellar cartilage T2 (mono-exponential decay curve with five echoes [9.7-67.9ms]), and patellar and trochlear tAB were determined. The annual increase in both patellar and trochlear cartilage thickness was 0.8% (95% confidence interval [CI] 0.6, 1.0) and 0.6% (0.3, 0.9), for adolescent males and females respectively; the longitudinal gain in patellar and trochlear tAB was 1.3% (1.1, 1.5) and 0.5% (0.2, 0.8), and 1.6% (1.1, 2.2) and 0.8% (0.3, 0.7) for adolescent males and females, respectively (no significant between-sex differences). Mature athletes showed smaller gains in tAB, and loss of <1% of cartilage thickness annually. While no significant sex-differences existed in adolescent patellar T2 changes, mature males gained significantly greater T2 than mature females (p=0.002-0.013). Patellar and trochlear cartilage thickness and tAB were observed to increase in young athletes in late adolescence, without significant differences between sexes. Mature athletes displayed patellar cartilage loss (and T2 increases in mature males), potentially reflecting degenerative changes. Copyright © 2017 Elsevier B.V. All rights reserved.

Reconstruction of a ruptured patellar tendon using ipsilateral semitendinosus and gracilis tendons with preserved distal insertions: two case reports

PubMed Central

2013-01-01

Background Acute patellar tendon ruptures with poor tissue quality. Ruptures that have been neglected are difficult to repair. Several surgical techniques for the repair of the patellar tendon have been reported, however, these techniques remain difficult because of contractures, adhesions, and atrophy of the quadriceps muscle after surgery. Case presentation We report the cases of 2 Japanese patients (Case 1: a 16-year-old male and Case 2: a 43-year-old male) with patellar tendon ruptures who were treated by reconstruction using semitendinosus-gracilis (STG) tendons with preserved distal insertions. Retaining the original insertion of the STG appears to preserve its viability and provide the revascularization necessary to accelerate healing. Both tendons were placed in front of the patella, in a figure-of-eight fashion, providing stability to the patella. Conclusion Both patients recovered near normal strength and stability of the patellar tendon as well as restoration of function after the operation. PMID:24010848

Arthroscopic treatment of chronic patellar tendinopathy in high-level athletes

PubMed Central

Alaseirlis, Dimosthenis Artemis; Konstantinidis, George Athanasios; Malliaropoulos, Nikolaos; Nakou, Lamprini Stefanos; Korompilias, Anastasios; Maffulli, Nicola

2012-01-01

Summary To present the results of arthroscopic treatment of patellar tendinopathy in high-level competition athletes. Eleven high-level athletes presented chronic patellar tendinopathy which did not respond to long term conservative treatment. Average age of the patients was 24.8 ±3.4 years old. All patients received an arthroscopic procedure with osteoplasty of the distal patellar pole, debridement of the underlying Hoffa fat pad and of the degenerated areas of the proximal posterior patella tendon and cauterization of the visible neo-vessels. Mean duration of follow-up was 17.4±4 months. Patients showed a major improvement in the Lysholm score from 49.9±5.2 to 92.5±7 and in the VISA P score from 41.2±5.2 to 86.8±14.9 on tenth post-operative week. All patients had returned to sports activities by the twelfth postoperative week. Arthroscopic treatment of chronic patellar tendinopathy found to be a minimal invasive and safe technique which produced satisfactory results. PMID:23738308

PT-12, a putative ras-activated proliferation-dependent gene, is expressed in patellar tendon and not in anterior cruciate ligament.

PubMed

Goomer, R S; Maris, T; Ostrander, R; Amiel, D

1999-09-01

We describe a gene (PT-12) that is expressed in the patellar tendon and not in the anterior cruciate ligament. We used a recently developed polymerase chain reaction-based subtractive cDNA analysis to discover genes that are overexpressed in the patellar tendon but not expressed in the anterior cruciate ligament; the long-term objective was to find genes that are central to the self-repair of the patellar tendon, in contrast with the inability of the anterior cruciate ligament to launch a repair response following injury. PT-12 is a homologue of human S2 or mouse LLRep3 ribosomal genes, which are known to be overexpressed in highly proliferating cells. This study opens a new vista to the development of techniques and reagents to study the differences between two periarticular tissues (i.e., the patellar tendon and anterior cruciate ligament) that differ primarily in their ability to self-repair.

Determination of the normal arthroscopic anatomy of the femoropatellar and cranial femorotibial joints of cattle.

PubMed

Nichols, Sylvain; Anderson, David E

2014-03-01

The arthroscopic approach and anatomy of the bovine femoropatellar and femorotibial joints are described. A 4-mm diameter, 15-cm long arthroscope with a 30° forward angle view was used. The structures viewed were recorded according to the position of the arthroscope within the joint. The femoropatellar joint was best accessed via a lateral approach, between the middle and lateral patellar ligaments. The axial portion of the medial femorotibial joint was viewed from a medial approach between the middle and medial patellar ligaments and the abaxial portion was viewed from a lateral approach between the middle and the lateral patellar ligaments. The axial portion of the lateral femorotibial joint was viewed from a lateral approach between the middle and the lateral patellar ligaments and the abaxial portion was viewed from a medial approach between the middle and medial patellar ligaments. The results of this study provide guidelines regarding the location of arthroscopic portals to evaluate precisely different areas of the stifle in cattle.

Determination of the normal arthroscopic anatomy of the femoropatellar and cranial femorotibial joints of cattle

PubMed Central

Nichols, Sylvain; Anderson, David E.

2014-01-01

The arthroscopic approach and anatomy of the bovine femoropatellar and femorotibial joints are described. A 4-mm diameter, 15-cm long arthroscope with a 30° forward angle view was used. The structures viewed were recorded according to the position of the arthroscope within the joint. The femoropatellar joint was best accessed via a lateral approach, between the middle and lateral patellar ligaments. The axial portion of the medial femorotibial joint was viewed from a medial approach between the middle and medial patellar ligaments and the abaxial portion was viewed from a lateral approach between the middle and the lateral patellar ligaments. The axial portion of the lateral femorotibial joint was viewed from a lateral approach between the middle and the lateral patellar ligaments and the abaxial portion was viewed from a medial approach between the middle and medial patellar ligaments. The results of this study provide guidelines regarding the location of arthroscopic portals to evaluate precisely different areas of the stifle in cattle. PMID:24587506

The Effect of Patellar Taping on Squat Depth and the Perception of Pain in People with Anterior Knee Pain

PubMed Central

Clifford, Amanda M.; Harrington, Elaine

Patellar taping is a treatment adjunct commonly used in the management of anterior knee pain. The aim of this cross sectional study was to investigate the effects of medial glide patellar taping on sagittal plane lower-limb joint kinematics and knee pain during a unilateral squat in a symptomatic population complaining of anterior knee pain. Ten participants with a history of unilateral or bilateral anterior knee pain were included in the study. Subjects were required to squat on the symptomatic leg under three conditions: placebo tape, patellar tape and no tape. Kinematic data was recorded using the CODA mpx64 motion analysis system and subjects’ pain was assessed using the Numerical Rating Scale. Patellar taping resulted in a significantly greater single-legged squat depth compared to placebo tape (p=0.008) and no tape (p=0.001) and a statistically significant reduction in pain during a squat compared to placebo tape (p=0.001) or no tape (p=0.001). Significant differences were not identified for maximum knee flexion in the patella taping compared to the no tape condition. This study may have significant clinical implications as participants reported less pain and alterations in sagittal plane movement following the application of patellar tape. PMID:24146711

Comparison of patellofemoral outcomes after TKA using two prostheses with different patellofemoral design features.

PubMed

Bae, Dae Kyung; Baek, Jong Hun; Yoon, Kyung Tack; Son, Hyuck Sung; Song, Sang Jun

2017-12-01

The purpose of the present study was to compare the clinical and radiographic results after TKA using two prostheses with different sagittal patellofemoral design features, including outcomes related to compatibility of the patellofemoral joint. The clinical and radiographic results of 81 patients (100 knees) who underwent TKA using the specific prosthesis (group A) were compared with those in a control group who underwent TKA using the other prosthesis (group B). The presence of anterior knee joint pain, patellar crepitation, and patellar clunk syndrome was also checked. The function score and maximum flexion angle at the last follow-up were slightly better in group A than those in group B (92.0 ± 2.3 vs. 90.6 ± 4.2) (133.6° ± 8.4° vs. 129.6° ± 11.4°). Anterior knee pain was observed in 6 knees and patellar crepitation in four knees in group A. In group B, these symptoms were observed in 22 knees and 18 knees, respectively. There was no patellar clunk syndrome in either group. The alignment was corrected with satisfactory positioning of components. The patellar height remained unchanged after TKA in the two groups. The differences between preoperative and postoperative patellar tilt angle and patellar translation were small. When comparing the clinical and radiographic results after TKA using two prostheses with different sagittal patellofemoral design features, TKA using the specific prosthesis provided satisfactory results with less clinical symptoms related to the patellofemoral kinematics with TKA using the other prosthesis. III.

Changes in patellofemoral alignment do not cause clinical impact after open-wedge high tibial osteotomy.

PubMed

Lee, Yong Seuk; Lee, Sang Bok; Oh, Won Seok; Kwon, Yong Eok; Lee, Beom Koo

2016-01-01

The objectives of this study were (1) to evaluate the clinical and radiologic outcomes of open-wedge high tibial osteotomy focusing on patellofemoral alignment and (2) to search for correlation between variables and patellofemoral malalignment. A total of 46 knees (46 patients) from 32 females and 14 males who underwent open-wedge high tibial osteotomy were included in this retrospective case series. Outcomes were evaluated using clinical scales and radiologic parameters at the last follow-up. Pre-operative and final follow-up values were compared for the outcome analysis. For the focused analysis of the patellofemoral joint, correlation analyses between patellofemoral variables and pre- and post-operative weight-bearing line (WBL), clinical score, posterior slope, Blackburn Peel ratio, lateral patellar tilt, lateral patellar shift, and congruence angle were performed. The minimum follow-up period was 2 years and median follow-up period was 44 months (range 24-88 months). The percentage of weight-bearing line was shifted from 17.2 ± 11.1 to 56.7 ± 12.7%, and it was statistically significant (p < 0.01). Regarding the clinical results, statistical significance was observed using all scores (p < 0.01). In the radiologic evaluation, patellar descent was observed with statistical significance (p < 0.01). Last follow-up lateral patellar tilt was decreased with statistical significance (p < 0.01). In correlation analysis between variables of patellofemoral malalignment, the pre-operative weight-bearing line showed an association with the change in lateral patellar tilt and lateral patellar shift (correlation coefficient: 0.3). After open-wedge high tibial osteotomy, clinical results showed improvement, compared to pre-operative values. The patellar tilt and lateral patellar shift were not changed; however, descent of the patella was observed. Therefore, mild patellofemoral problems should not be a contraindication of the open-wedge high tibial osteotomy. Case series, Level IV.

Management of patellar fracture with titanium cable cerclage

PubMed Central

Huang, Sheng-Li; Xue, Jian-Li; Gao, Zong-Qiang; Lan, Bin-Shang

2017-01-01

Abstract Early rehabilitation after surgery for patellar fracture is challenging. The purpose of this study was to evaluate the surgical outcome of titanium cable cerclage for patellar fracture in early functional activity. We reviewed a series of 24 patients treated at our hospital with titanium cable. Functional exercises were started early. Patients were followed up for at least 12 months. Fifteen were males and 9 were females. Fracture occurred in the right knee in 13 patients and in the left knee in 11 patients. The most common mode of injury involves a tumble. None of the patients presented with any postoperative complications. The management resulted in satisfactory outcomes. Titanium cable cerclage offers a new strategy in treating patellar fracture. PMID:29095314

Knee injuries in women collegiate rugby players.

PubMed

Levy, A S; Wetzler, M J; Lewars, M; Laughlin, W

1997-01-01

We evaluated the prevalence and patterns of knee injuries in 810 women collegiate rugby players. Injuries that resulted in players missing at least one game were recorded and a questionnaire was used to delineate players' rugby and knee injury history. There were 76 total knee injuries in 58,296 exposures. This resulted in a 1.3 knee injury rate per 1000 exposures. Twenty-one anterior cruciate ligament tears were reported for a 0.36 incidence per 1000 exposures. Other injuries included meniscal tears (25), medical collateral ligament sprains (23), patellar dislocations (5), and posterior cruciate ligament tears (2). Sixty-one percent of the medial collateral ligament sprains occurred in rugby forwards and 67% of anterior cruciate ligament tears occurred in rugby backs. All other injuries occurred with equal frequency in backs and forwards. This study demonstrates that knee injury rates in women's collegiate rugby are similar to those reported for other women's collegiate sports. The overall rate of anterior cruciate ligament injury in women's rugby, however, is slightly higher than that reported for women soccer and basketball players.

Patellar taping, patellofemoral pain syndrome, lower extremity kinematics, and dynamic postural control.

PubMed

Aminaka, Naoko; Gribble, Phillip A

2008-01-01

Patellar taping has been a part of intervention for treatment of patellofemoral pain syndrome (PFPS). However, research on the efficacy of patellar taping on lower extremity kinematics and dynamic postural control is limited. To evaluate the effects of patellar taping on sagittal-plane hip and knee kinematics, reach distance, and perceived pain level during the Star Excursion Balance Test (SEBT) in individuals with and without PFPS. Repeated-measures design with 2 within-subjects factors and 1 between-subjects factor. The University of Toledo Athletic Training Research Laboratory. Twenty participants with PFPS and 20 healthy participants between the ages of 18 and 29 years. The participants performed 3 reaches of the SEBT in the anterior direction under tape and no-tape conditions on both legs. The participants' hip and knee sagittal-plane kinematics were measured using the electromagnetic tracking system. Reach distance was recorded by hand and was normalized by dividing the distance by the participants' leg length (%MAXD). After each taping condition on each leg, the participants rated the perceived pain level using the 10-cm visual analog scale. The participants with PFPS had a reduction in pain level with patellar tape application compared with the no-tape condition (P = .005). Additionally, participants with PFPS demonstrated increased %MAXD under the tape condition compared with the no-tape condition, whereas the healthy participants demonstrated decreased %MAXD with tape versus no tape (P = .028). No statistically significant differences were noted in hip flexion and knee flexion angles. Although patellar taping seemed to reduce pain and improve SEBT performance of participants with PFPS, the exact mechanisms of these phenomena cannot be explained in this study. Further research is warranted to investigate the effect of patellar taping on neuromuscular control during dynamic postural control.

A rare case report of Patellar Osteochondroma

PubMed Central

Bhatnagar, Abhinav S.; Malhan, Kaushal; Mehta, Sonu

2015-01-01

Introduction: Osteochondroma (OC) is the most common benign tumor of the skeleton. However, patellar OC is very rare. Only five case reports have been published yet and only 1 after the year 1972. OCs grow during childhood through adolescence, but usually growing ends when the epiphyseal plates close. In an adult, the growth of an OC suggests the diagnosis of malignant transformation to a chondrosarcoma. However, enlargement of a patellar OC reported as benign after skeletal maturity is present in literature. Case Report: We report the clinical and radiologic findings of a patellar OC in a 50-year-old female, with a 3-year progression of swelling, not painful, well-defined margins, normal skin, and no neurovascular deficits or functional impairment. The tumor was surgically resected, and histopathological examination did not show malignancy. After 2 years of follow-up, the patient has no complaints and no signs of recurrence. Conclusion: Patellar OCsare extremely rare with only a few reports published. It should be kept in mind that benign OCs can show symptomatic growth in skeletally mature patients without malignant transformation. PMID:27299076

Bilateral Patellar Tendon Rupture.

PubMed

Kamienski, Mary

The knee is the most complex and largest joint in the body. Injuries to any part of this joint affect the entire body. There are multiple injuries that can occur to the knee, with the most common being ligament and meniscus tears. A not-so-common injury to the knee is a patellar tendon rupture. A bilateral patellar tendon rupture is extremely rare. A case study of a 43-year-old man who sustained a bilateral patellar tendon rupture while playing softball is used to present this devastating injury. This discussion includes the incidence and diagnosis of the tear, surgical repair, as well as a description of the comprehensive rehabilitation process necessary to allow the patient to return to normal physical activity. Risks and complications of this surgery and the expected outcomes are also presented.

Surgical Treatment for Failure of Repair of Patellar and Quadriceps Tendon Rupture With Ipsilateral Hamstring Tendon Graft.

PubMed

Maffulli, Nicola; Papalia, Rocco; Torre, Guglielmo; Denaro, Vincenzo

2017-03-01

Tears of the patellar and quadriceps tendon are common in the active population, especially in athletes. At present, several techniques for surgical repair and reconstruction are available. When reruptures occur, a reconstruction is mandatory. In the present paper, we describe a surgical technique for patellar and quadriceps tendon reconstruction using ipsilateral hamstring autograft. After routine hamstring tendon harvesting, the tendon ends are prepared using a whip stitch. A transverse tunnel is drilled in the midportion of the patella, the hamstring graft is passed through the patella, and firmly secured to the patellar tunnel openings with sutures. The details of the technique are fully described. Autologous ipsilateral hamstring tendon grafts provide a secure sound means to manage these challenging injuries.

The TOPSHOCK study: Effectiveness of radial shockwave therapy compared to focused shockwave therapy for treating patellar tendinopath - design of a randomised controlled trial

PubMed Central

2011-01-01

Background Patellar tendinopathy is a chronic overuse injury of the patellar tendon that is especially prevalent in people who are involved in jumping activities. Extracorporeal Shockwave Therapy is a relatively new treatment modality for tendinopathies. It seems to be a safe and promising part of the rehabilitation program for patellar tendinopathy. Extracorporeal Shockwave Therapy originally used focused shockwaves. Several years ago a new kind of shockwave therapy was introduced: radial shockwave therapy. Studies that investigate the effectiveness of radial shockwave therapy as treatment for patellar tendinopathy are scarce. Therefore the aim of this study is to compare the effectiveness of focussed shockwave therapy and radial shockwave therapy as treatments for patellar tendinopathy. Methods/design The TOPSHOCK study (Tendinopathy Of Patella SHOCKwave) is a two-armed randomised controlled trial in which the effectiveness of focussed shockwave therapy and radial shockwave therapy are directly compared. Outcome assessors and patients are blinded as to which treatment is given. Patients undergo three sessions of either focused shockwave therapy or radial shockwave therapy at 1-week intervals, both in combination with eccentric decline squat training. Follow-up measurements are scheduled just before treatments 2 and 3, and 1, 4, 7 and 12 weeks after the final treatment. The main outcome measure is the Dutch VISA-P questionnaire, which asks for pain, function and sports participation in subjects with patellar tendinopathy. Secondary outcome measures are pain determined with a VAS during ADL, sports and decline squats, rating of subjective improvement and overall satisfaction with the treatment. Patients will also record their sports activities, pain during and after these activities, and concurrent medical treatment on a weekly basis in a web-based diary. Results will be analysed according to the intention-to-treat principle. Discussion The TOPSHOCK study is the first randomised controlled trial that directly compares the effectiveness of focused shockwave therapy and radial shockwave therapy, both in combination with eccentric decline squat training, for treating patellar tendinopathy. Trial registration Trial registration number NTR2774. PMID:21989041

Are unilateral and bilateral patellar tendinopathy distinguished by differences in anthropometry, body composition, or muscle strength in elite female basketball players?

PubMed Central

Gaida, J; Cook, J; Bass, S; Austen, S; Kiss, Z

2004-01-01

Background: Overuse injury to the patellar tendon (patellar tendinopathy) is a major reason for interrupted training and competition for elite athletes. In both sexes, the prevalence of unilateral and bilateral tendinopathy has been shown to differ. It has been proposed that bilateral pathology may have a different aetiology from unilateral pathology. Investigation of risk factors that may be unique to unilateral and bilateral patellar tendinopathy in female athletes may reveal insights into the aetiology of this condition. Objectives: To examine whether anthropometry, body composition, or muscle strength distinguished elite female basketball players with unilateral or bilateral patellar tendinopathy. Methods: Body composition, anthropometry, and muscle strength were compared in elite female basketball players with unilateral (n = 8), bilateral (n = 7), or no (n = 24) patellar tendinopathy. Body composition was analysed using a dual energy x ray absorptiometer. Anthropometric measures were assessed using standard techniques. Knee extensor strength was measured at 180°/s using an isokinetic dynamometer. z scores were calculated for the unilateral and bilateral groups (using the no tendinopathy group as controls). z scores were tested against zero. Results: The tibia length to stature ratio was approximately 1.3 (1.3) SDs above zero in both the affected and non-affected legs in the unilateral group (p<0.05). The waist to hip ratio was 0.66 (0.78) SD above zero in the unilateral group (p<0.05). In the unilateral group, leg lean to total lean ratio was 0.42 (0.55) SD above zero (p<0.07), the trunk lean to total lean ratio was 0.63 (0.68) SD below zero (p<0.05), and leg fat relative to total fat was 0.47 (0.65) SD below zero (p<0.09). In the unilateral group, the leg with pathology was 0.78 (1.03) SD weaker during eccentric contractions (p<0.07). Conclusions: Unilateral patellar tendinopathy has identifiable risk factors whereas bilateral patellar tendinopathy may not. This suggests that the aetiology of these conditions may be different. However, interpretation must respect the limitation of small subject numbers. PMID:15388543

Patellar tendinopathy in young elite soccer- clinical and sonographical analysis of a German elite soccer academy.

PubMed

Bode, Gerrit; Hammer, Thorsten; Karvouniaris, N; Feucht, M J; Konstantinidis, L; Südkamp, N P; Hirschmüller, A

2017-08-08

The prevalence of patellar tendinopathy is elevated in elite soccer compared to less explosive sports. While the burden of training hours and load is comparably high in youth elite players (age < 23 years), little is known about the prevalence of patellar tendinopathy at this age. There is only little data available on the influence of age, the amount of training, the position on the field, as well as muscular strength, range of motion, or sonographical findings in this age group. The purpose of the present study was to examine the above-mentioned parameters in all age groups of a German youth elite soccer academy. One hundred nineteen male youth soccer players (age 15,97 ± 2,24 years, height 174, 60 ± 10,16 cm, BMI 21, 24 ± 2,65) of the U-13 to U-23 teams were part of the study. Data acquisition included sport specific parameters such as footwear, amount of training hours, leg dominance, history of tendon pathologies, and clinical examination for palpatory pain, indurations, muscular circumference, and range of motion. Subjective complaints were measured with the Victorian Institute of Sport Assessment Patellar (VISA-P) Score. Furthermore, sonographical examinations (Aplio SSA-770A/80; Toshiba, Tokyo, Japan) with 12-MHz multifrequency linear transducers (8-14 MHz) of both patellar tendons were performed with special emphasis on hyper- and hypo echogenic areas, diameter and neovascularization. The prevalence of patellar tendinopathies was 13.4%. Seventy-five percent of the players complained of pain of their dominant leg with onset of pain at training in 87.5%. The injured players showed a medium amount of 10.34 ± 3.85 training hours and a medium duration of symptoms of 11.94 ± 18.75 weeks. Two thirds of players with patellar tendinopathy were at the age of 15-17 (Odds ratio 1.89) while no differences between players of the national or regional league were observed. In case of patellar tendinopathy, VISA-P was significantly lower in comparison to healthy players (mean ± SD 76.80 ± 28.56 points vs. 95.85 ± 10.37). The clinical examination revealed local pain at the distal patella, pain at stretching, and thickening of the patellar tendon (p = 0.02). The mean tendon diameter measured 2 cm distally to the patella was 4.10 ± 0.68 mm with a significantly increased diameter of 0.15 mm in case of an underlying tendinopathy (p = 0.00). The incidence of hypo-echogenic areas and neovascularizations was significantly elevated in players with patellar tendon syndrome (PTS) (p = 0.05). The prevalence of patellar tendinopathy in youth elite soccer is relatively high in comparison to available data of adult players. Especially players at the age of 15 to 17 are at considerable risk. Tendon thickening, hypo-echogenic areas, and neovascularization are more common in tendons affected by PTS.

Treatment of Patellar Tendinopathy Refractory to Surgical Management Using Percutaneous Ultrasonic Tenotomy and Platelet-Rich Plasma Injection: A Case Presentation.

PubMed

Nanos, Katherine N; Malanga, Gerard A

2015-12-01

Chronic proximal patellar tendinopathy is a common condition in sports medicine that may be refractory to nonoperative treatments, including activity modification, medications, and comprehensive rehabilitation. Percutaneous ultrasonic tenotomy is a recently developed technique designed to cut and debride tendinopathic tissue, thus promoting pain relief and functional recovery. We present a case of a collegiate athlete with chronic proximal patellar tendinopathy who was effectively treated with percutaneous ultrasonic tenotomy after not responding to extensive nonoperative treatment, surgical debridement, and platelet-rich plasma injections. Percutaneous ultrasonic tenotomy can be considered as a treatment option in patients presenting with refractory proximal patellar tendinopathy, including those who do not respond to previous operative intervention. Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Biomechanical Assessment of Patellar Advancement Procedures for Patella Alta.

PubMed

Seidl, Adam; Baldini, Todd; Krughoff, Kevin; Shapiro, Joshua A; Lindeque, Bennie; Rhodes, Jason; Carollo, James

2016-05-01

Crouch gait deformity is common in children with cerebral palsy and often is associated with patella alta. Patellar tendon advancement typically is used to correct patella alta and restore normal knee mechanics. The purpose of this study was to determine the mechanical strength of surgical constructs used for fixation during patellar advancement procedures. This study used a cadaveric model to determine which of 3 surgical techniques is biomechanically optimal for patellar tendon advancement in treating patella alta. Twenty-four human cadaveric knees (8 per group) were prepared using 1 of 3 different common surgical techniques: tibial tubercle osteotomy, patellar tendon partial resection and repair at the distal patella, and patellar tendon imbrication. The patella was loaded from 25 to 250 N at 1 Hz for 1000 cycles. A significant difference in patella displacement under cyclical loading was found between surgical techniques. Tibial tubercle osteotomy exhibited significantly less displacement under cyclical loading than distal patella excision and repair (P<.0001) or imbrication (P=.0088). Imbrication exhibited significantly less displacement than distal patella excision and repair (P=.0006). Tibial tubercle osteotomy survived longest. Based on failure criteria of 5 mm of displacement, tibial tubercle osteotomy lasted between 250 and 500 cycles. The other 2 techniques failed by 25 cycles. This study offers quantitative evidence regarding the relative mechanical strength of each construct and may influence choice of surgical technique. [Orthopedics. 2016; 39(3):e492-e497.]. Copyright 2016, SLACK Incorporated.

Astym® Therapy for the Management of Recalcitrant Knee Joint Stiffness after Total Knee Arthroplasty.

PubMed

Bhave, Anil; Corcoran, James; Cherian, Jeffery J; Mont, Michael A

2016-01-01

Knee stiffness is a common complication after total knee arthroplasty (TKA). Despite studies published on the surgical management of reduced range of motion (ROM) after TKA, there is limited evidence on the nonoperative management of joint and soft tissue imbalances possibly contributing to reduced knee ROM. This report assesses changes in ROM, pain, function, and patellar tendon length after Astym® joint mobilization use. A 38-year-old male professional skier had a right TKA 3 months before presentation with 2 subsequent manipulations under anesthesia secondary to persistent knee stiffness. He had patellar baja on radiograph, a reduced arc of ROM, reduced patellar mobility and muscular extensibility, and pain to palpation along the patellar tendon. He had 12 visits of physical therapy with the use of Astym®, patellar mobilization, and tibio-femoral mobilizations with movement. The patient also used a customized knee device at home for prolonged knee extension stretching. The patient was treated for 12 visits, along with home use of customized bracing for knee extension. Significant improvements were seen in pain, function, and ROM. He returned to work full-time, ambulated prolonged distances, and negotiated stairs pain-free. He also demonstrated resolution of patellar baja radiographically. Conservative management of recalcitrant knee joint stiffness after primary TKA can be effective in restoring knee mobility and reducing pain and activity limitation. A multimodal approach using Astym® treatment, customized knee bracing, and targeted joint mobilization can be effective in resolving knee joint stiffness.

Comparing the effects of eccentric training with eccentric training and static stretching exercises in the treatment of patellar tendinopathy. A controlled clinical trial.

PubMed

Dimitrios, Stasinopoulos; Pantelis, Manias; Kalliopi, Stasinopoulou

2012-05-01

The aim of the present study was to investigate the effectiveness of eccentric training and eccentric training with static stretching exercises in the management of patellar tendinopathy. Controlled clinical trial. Rheumatology and rehabilitation centre. Forty-three patients who had patellar tendinopathy for at least three months. They were allocated to two groups by alternative allocation. Group A (n = 22) was treated with eccentric training of patellar tendon and static stretching exercises of quadriceps and hamstrings and Group B (n = 21) received eccentric training of patellar tendon. All patients received five treatments per week for four weeks. Pain and function were evaluated using the VISA-P score at baseline, at the end of treatment (week 4), and six months (week 24) after the end of treatment. At the end of treatment, there was a rise in VISA-P score in both groups compared with baseline (P<0.0005, paired t test). There were significant differences in the VISA-P score between the groups at the end of treatment (+14; 10 to 18) and at the six-month follow-up (+19; 13 to 24); eccentric training and static stretching exercises produced the largest effect (P<0.0005, one-way ANOVA). Eccentric training and static stretching exercises is superior to eccentric training alone to reduce pain and improve function in patients with patellar tendinopathy at the end of the treatment and at follow-up.

Patellar tendon load in different types of eccentric squats.

PubMed

Frohm, A; Halvorsen, K; Thorstensson, A

2007-07-01

Differences in mechanical loading of the patellar tendon have been suggested as a reason for varying effects in rehabilitation of patellar tendinopathy using different eccentric squat exercises and devices. The aim was to characterize the magnitude and pattern of mechanical load at the knee and on the patellar tendon during four types of eccentric squat. Subjects performed squats with a submaximal free weight and with maximal effort in a device for eccentric overloading (Bromsman), on a decline board and horizontal surface. Kinematics was recorded with a motion-capture system, reaction forces with force plates, and electromyography from three leg muscles with surface electrodes. Inverse dynamics was used to calculate knee joint kinetics. Eccentric work, mean and peak patellar tendon force, and angle at peak force were greater (25-30%) for squats on decline board compared to horizontal surface with free weight, but not in Bromsman. Higher knee load forces (60-80%), but not work, were observed with Bromsman than free weight. Angular excursions at the knee and ankle were larger with decline board, particularly with free weight, and smaller in Bromsman than with free weight. Mean electromyography was greater on a decline board for gastrocnemius (13%) and vastus medialis (6%) with free weight, but in Bromsman only for gastrocnemius (7%). The results demonstrated clear differences in the biomechanical loading on the knee during different squat exercises. Quantification of such differences provides information that could be used to explain differences in rehabilitation effects as well as in designing more optimal rehabilitation exercises for patellar tendinopathy.

Quantitative analysis of the patellofemoral motion pattern using semi-automatic processing of 4D CT data.

PubMed

Forsberg, Daniel; Lindblom, Maria; Quick, Petter; Gauffin, Håkan

2016-09-01

To present a semi-automatic method with minimal user interaction for quantitative analysis of the patellofemoral motion pattern. 4D CT data capturing the patellofemoral motion pattern of a continuous flexion and extension were collected for five patients prone to patellar luxation both pre- and post-surgically. For the proposed method, an observer would place landmarks in a single 3D volume, which then are automatically propagated to the other volumes in a time sequence. From the landmarks in each volume, the measures patellar displacement, patellar tilt and angle between femur and tibia were computed. Evaluation of the observer variability showed the proposed semi-automatic method to be favorable over a fully manual counterpart, with an observer variability of approximately 1.5[Formula: see text] for the angle between femur and tibia, 1.5 mm for the patellar displacement, and 4.0[Formula: see text]-5.0[Formula: see text] for the patellar tilt. The proposed method showed that surgery reduced the patellar displacement and tilt at maximum extension with approximately 10-15 mm and 15[Formula: see text]-20[Formula: see text] for three patients but with less evident differences for two of the patients. A semi-automatic method suitable for quantification of the patellofemoral motion pattern as captured by 4D CT data has been presented. Its observer variability is on par with that of other methods but with the distinct advantage to support continuous motions during the image acquisition.

Incidence and Epidemiology of Patellar Fractures.

PubMed

Larsen, Peter; Court-Brown, Charles M; Vedel, Julie Odgaard; Vistrup, Sabina; Elsoe, Rasmus

2016-11-01

The literature lacks large-scale, up-to-date, population-based epidemiology studies on the incidence of patellar fractures based on complete populations. The purpose of this study was to provide up-to-date information concerning the incidence of patellar fractures in a large and complete population spanning a decade and to report on the distribution of fracture classification, trauma mechanisms, and patient baseline demographics. A retrospective review of clinical and radiological records of 756 patellar fractures treated between 2005 and 2014 was conducted. Mean age at the time of fracture was 54±21 years. Mean age was 46±22 years for males and 61±18 years for females. The sex distribution was 425 (56%) females and 331 (44%) males. The incidence of patellar fractures between 2005 and 2014 was 13.1/100,000/ year with a year-to-year variation between 10.5 and 16.5/100,000/year during the 10-year observation period. The distribution of incidence shows an increase with increasing age. Males have the highest incidence of fracture in the 10-to-19-year age group, approximately 15.4/100,000/year. Females in the 60-to-80-year age group have the highest incidence, approximately 36/100,000/year. AO type 34-C3 was the most common fracture type, representing 25% of all patellar fractures, followed by AO type 34-C1, representing 23%. [Orthopedics. 2016; 39(6):e1154-e1158.]. Copyright 2016, SLACK Incorporated.

Knee isokinetic performance following anterior cruciate ligament reconstruction: patellar tendon versus hamstrings graft.

PubMed

Machado, Felipe; Debieux, Pedro; Kaleka, Camila Cohen; Astur, Diego; Peccin, Maria Stella; Cohen, Moisés

2018-02-01

To compare knee isokinetic performance six months after reconstruction of the anterior cruciate ligament using grafts from either the patellar tendon or the hamstrings among patients who underwent the same rehabilitation protocol. Thirty-four patients were evaluated (17 with grafts from the patellar tendon and 17 with grafts from the hamstrings). Operated and non-operated knees were compared with regards to the variables of peak torque, work and the hamstring/quadriceps relationship at velocities of 60º/s and 180º/s and power of 180º/s after six months of surgery. The patients with ACL reconstruction using the patellar tendon (BPTB) showed quadriceps deficits for all variables, but the flexor musculature was balanced. In the hamstring group, both the extensors and the flexors showed deficits for the variables analyzed, except for hamstring power at 180º/s. Patients in the patellar tendon group had a greater quadriceps deficit compared with those in the hamstrings group. Patients in the hamstrings group had a greater muscular deficit in the flexor mechanism compared with the contralateral knee. An unbalanced H/Q ratio was observed regardless of graft type, but this was more evident in the BPTB group.

Effects of Patellofemoral Taping on Patellofemoral Joint Alignment and Contact Area During Weight Bearing.

PubMed

Ho, Kai-Yu; Epstein, Ryan; Garcia, Ron; Riley, Nicole; Lee, Szu-Ping

2017-02-01

Study Design Controlled laboratory study. Background Although it has been theorized that patellofemoral joint (PFJ) taping can correct patellar malalignment, the effects of PFJ taping techniques on patellar alignment and contact area have not yet been studied during weight bearing. Objective To examine the effects of 2 taping approaches (Kinesio and McConnell) on PFJ alignment and contact area. Methods Fourteen female subjects with patellofemoral pain and PFJ malalignment participated. Each subject underwent a pretaping magnetic resonance imaging (MRI) scan session and 2 MRI scan sessions after the application of the 2 taping techniques, which aimed to correct lateral patellar displacement. Subjects were asked to report their pain level prior to each scan session. During MRI assessment, subjects were loaded with 25% of body weight on their involved/more symptomatic leg at 0°, 20°, and 40° of knee flexion. The outcome measures included patellar lateral displacement (bisect-offset [BSO] index), mediolateral patellar tilt angle, patellar height (Insall-Salvati ratio), contact area, and pain. Patellofemoral joint alignment and contact area were compared among the 3 conditions (no tape, Kinesio, and McConnell) at 3 knee angles using a 2-factor, repeated-measures analysis of variance. Pain was compared among the 3 conditions using the Friedman test and post hoc Wilcoxon signed-rank tests. Results Our data did not reveal any significant effects of either McConnell or Kinesio taping on the BSO index, patellar tilt angle, Insall-Salvati ratio, or contact area across the 3 knee angles, whereas knee angle had a significant effect on the BSO index and contact area. A reduction in pain was observed after the application of the Kinesio taping technique. Conclusion In a weight-bearing condition, this preliminary study did not support the use of PFJ taping as a medial correction technique to alter the PFJ contact area or alignment of the patella. J Orthop Sports Phys Ther 2017;47(2):115-123. doi:10.2519/jospt.2017.6936.

The prevalence and clinical significance of sonographic tendon abnormalities in asymptomatic ballet dancers: a 24-month longitudinal study.

PubMed

Comin, Jules; Cook, Jill L; Malliaras, Peter; McCormack, Moira; Calleja, Michelle; Clarke, Andrew; Connell, David

2013-01-01

Sonographic abnormalities of the achilles and patellar tendons are common findings in athletes, and tendinopathy is a common cause of pain and disability in athletes. However, it is unclear whether the sonographic changes are pathological or adaptive, or if they predict future injury. We undertook a cohort study to determine what sonographic features of the achilles and patellar tendons are consistent with changes as a result of ballet training, and which may be predictive of future development of disabling tendon symptoms. The achilles and patellar tendons of 79 (35 male, 44 female) professional ballet dancers (members of the English Royal Ballet) were examined with ultrasound, measuring proximal and distal tendon diameters and assessing for the presence of hypoechoic change, intratendon defects, calcification and neovascularity. All subjects were followed for 24 months for the development of patellar tendon or achilles-related pain or injury severe enough to require time off from dancing. Sonographic abnormalities were common among dancers, both male and female, and in both achilles and patellar tendons. Disabling tendon-related symptoms developed in 10 dancers and 14 tendons: 7 achilles (3 right, 4 left) and 7 patellar (2 right, 5 left). The presence of moderate or severe hypoechoic defects was weakly predictive for the development of future disabling tendon symptoms (p=0.0381); there was no correlation between any of the other sonographic abnormalities and the development of symptoms. There was no relationship between achilles or patellar tendons' diameter, either proximal or distal, with an increased likelihood of developing tendon-related disability. The presence of sonographic abnormalities is common in ballet dancers, but only the presence of focal hypoechoic changes predicts the development of future tendon-related disability. This suggests that screening of asymptomatic individuals may be of use in identifying those who are at higher risk of developing tendon-related disability, which may in turn allow targeted modifications of training or other preventative regimens.

Trochleoplasty: Indications and Technique.

PubMed

Nolan, John E; Schottel, Patrick C; Endres, Nathan K

2018-05-09

Trochlear dysplasia is a well-described risk factor for patellar instability. Trochleoplasty has emerged as a procedure within the surgical armamentarium for patellar instability, yet its role is unclear. A variety of trochleoplasty procedures have emerged. The purpose of this review is to clarify indications for trochleoplasty, outline the technical steps involved in performing common trochleoplasties and report the published outcomes and potential complications of these procedures. Patellar instability with severe trochlear dysplasia is the main indication for trochleoplasty. Three types of trochleoplasty have emerged: (1) lateral facet elevation; (2) sulcus deepening; and (3) recession wedge. Deepening and recession wedge trochleoplasties are the most commonly performed. Trochleoplasty is a surgical option for addressing patellar instability in patients with severe trochlear dysplasia. Deepening and recession wedge trochleoplasties that address Dejour B and D dysplastic trochleas are the most studied, with both short- and midterm outcomes reported. Long-term outcomes are lacking and comparative studies are needed.

Successful conservative management of symptomatic bilateral dorsal patellar defects presenting with cartilage involvement and bone marrow edema: MRI findings.

PubMed

Kwee, Thomas C; Sonneveld, Heleen; Nix, Maarten

2016-05-01

The dorsal patellar defect is a relatively rare entity that involves the superolateral quadrant of the patella. It is usually considered to represent a delayed ossification process, although its exact origin remains unclear. Because of its usually innocuous nature and clinical course, invasive interventions are generally deemed unnecessary, although curretage has been successfully performed on symptomatic cases. This case report presents a rather unusual case of symptomatic bilateral dorsal patellar defects with cartilage involvement and widespread surrounding bone marrow edema as demonstrated by magnetic resonance imaging (MRI). Both cartilage involvement and bone marrow edema should be considered part of the spectrum of associated MRI findings that can be encountered in this entity. Furthermore, the presented case shows that symptomatic dorsal patellar defects can be treated conservatively with success and that (decrease of) pain symptoms are likely related to (decrease of) bone marrow edema.

Patellar tendinopathy: late-stage results from surgical treatment☆

PubMed Central

Cenni, Marcos Henrique Frauendorf; Silva, Thiago Daniel Macedo; do Nascimento, Bruno Fajardo; de Andrade, Rodrigo Cristiano; Júnior, Lúcio Flávio Biondi Pinheiro; Nicolai, Oscar Pinheiro

2015-01-01

Objective To evaluate the late-stage results from surgical treatment of patellar tendinopathy (PT), using the Visa score (Victorian Institute of Sport Tendon Study Group) and the Verheyden method. Methods This was a retrospective study in which the postoperative results from 12 patients (14 knees) who were operated between July 2002 and February 2011 were evaluated. The patients included in the study presented patellar tendinopathy that was refractory to conservative treatment, without any other concomitant lesions. Patients who were not properly followed up during the postoperative period were excluded. Results Using the Verheyden method, nine patients were considered to have very good results, two had good results and one had poor results. In relation to Visa, the mean was 92.4 points and only two patients had scores less than 70 points (66 and 55 points). Conclusion When surgical treatment for patellar tendinopathy is correctly indicated, it has good long-term results. PMID:26535202

Radiological characteristics of the knee joint in nail patella syndrome.

PubMed

Tigchelaar, S; Rooy, J de; Hannink, G; Koëter, S; van Kampen, A; Bongers, E

2016-04-01

Nail patella syndrome (NPS) is a skeletal dysplasia with patellofemoral dysfunction as a key symptom. We present the first in-depth radiological evaluation of the knee in a large series of NPS patients and describe the typical malformations. Conventional radiological examination of 95 skeletally mature patients with NPS was performed. Patellar morphology was classified according to the Wiberg classification as modified by Baumgartl and Ficat criteria, and trochlear shape was classified according to the Dejour classification. Patellar aplasia was present in 4/90 (4%), and patellar hypoplasia in 77/90 (86%) of patients. The prevailing patellar shapes were type III, type IV and Hunter's cap. No patellar shape genotype-phenotype association could be found. The malformations of the distal femur comprised shortening of the lateral femoral condyle in 46 out of 84 patients (55%), with a prominent anterior surface of the lateral femoral condyle in 47 out of 84 patients (56%) and a flat anterior surface of the medial femoral condyle in 78 out of 85 patients (92%). The trochlea was type A1 according to the Dejour classification in 79 out of 85 patients (93%). An easily recognisable characteristic quartet of malformations consisting of patellar aplasiaor hypoplasia and the malformations of the distal femur was found in 22 out of 81 patients (27%), with the majority displaying at least three malformations. The distinct malformations of the knee in nail patella syndrome are easily recognisable on conventional radiographs and lead to the correct interpretation of the aberrant morphology which is essential in the treatment of these patellofemoral disorders. ©2016 The British Editorial Society of Bone & Joint Surgery.

[Patellar bone deficiency in revision total knee arthroplasty].

PubMed

Kloiber, J; Goldenitsch, E; Ritschl, P

2016-05-01

Patellar bone deficiency in revision total knee arthroplasty (TKA) determines the surgical procedure. Different reconstructive and ablative techniques, dependent on the remaining bone stock, are described. The primary patella implant can be retained in up to 50 % of revision situations. Reasons for replacement are aseptic and septic loosening, implant failure, expanding osteolysis, maltracking of the patella and "metal-backed" prosthesis. The aim of the reconstruction is the stable fixation and proper tracking of the implant by restoring the extensor mechanism. Dependent on the extent of bone loss and the availability of a patellar rim, the following surgical procedures are recommended. When the remaining bone thickness is 10 mm or more: implantation of a polyethylene "onlay-type" patella; when it is between 6-9 mm and there is an intact patellar rim: reconstruction with a biconvex "inlay-type" patella implant, where the biconvex shape replaces the bone defect partially. When there is deficient bone stock (less than 6 mm) or no cortical patellar rim then augmenting procedures with autologous spongiosa and procedures such as "impaction bone grafting", "trabecular metal" prosthesis, where the trabecular part of the implant serves as the base for the cemented polyethylene button, "gull-wing" osteotomy, which is an adapting and configuring technique of osteotomy; and in exceptional cases patelloplasty or patellectomy are used. Regarding the importance of the patellar component in biomechanics of the joint and function of the extensor mechanism, the reconstruction of the patella should be the primary aim. Patelloplasty or patellectomy should be avoided.

Hamstring tendon versus patellar tendon anterior cruciate ligament reconstruction using biodegradable interference fit fixation: a prospective matched-group analysis.

PubMed

Wagner, Michael; Kääb, Max J; Schallock, Jessica; Haas, Norbert P; Weiler, Andreas

2005-09-01

There are still controversies about graft selection for primary anterior cruciate ligament reconstruction, especially with respect to knee stability and functional outcome. Biodegradable interference screw fixation of hamstring tendon grafts provides clinical results similar to those achieved with identical fixation of bone-patellar tendon-bone grafts. Cohort study; Level of evidence, 2. In 1996 and 1997, primary isolated anterior cruciate ligament reconstruction using a bone-patellar tendon-bone autograft was performed in 72 patients. Since 1998, hamstring tendons were used as routine grafts. Matched patients with a hamstring tendon graft were selected from a database (n = 284). All patients were followed prospectively for a minimum of 2 years with KT-1000 arthrometer testing, International Knee Documentation Committee score, and Lysholm score. In the bone-patellar tendon-bone group, 9 patients were excluded because of bilateral rupture of the anterior cruciate ligament, 3 patients (4.2%) had a graft rupture, and 4 patients were lost to follow-up (follow-up rate, 92.1%), leaving 56 patients for a matched-group analysis. In the hamstring tendon database, the graft rupture rate was 5.6% (P = .698). The Lysholm score was 89.7 in the patellar tendon group and 94 in the hamstring tendon group (P = .003). The KT-1000 arthrometer side-to-side difference was 2.6 mm for the patellar tendon group and 2.1 mm for the hamstring tendon group (P = .041). There were significantly less positive pivot-shift test results in the hamstring tendon group (P = .005), and hamstring tendon patients showed lower thigh atrophy (P = .024) and patellofemoral crepitus (P = .003). Overall International Knee Documentation Committee scores were better (P = .001) in the hamstring tendon group (hamstring tendon: 34 x A, 21 x B, 0 x C, 0 x D; bone-patellar tendon-bone: 17 x A, 32 x B, 6 x C, 0 x D). In this comparison of anterior cruciate ligament reconstruction with bone-patellar tendon-bone and anatomical hamstring tendon grafts, the hamstring tendon graft was superior in knee stability and function. These findings are partially contrary to previous studies and might be attributable to the use of an anatomical joint line fixation for hamstring tendon grafts. Thus, hamstring tendons are the authors' primary graft choice for anterior cruciate ligament reconstruction, even in high-level athletes.

Suture anchor repair of patellar tendon rupture after total knee arthroplasty.

PubMed

Kamath, Atul F; Shah, Roshan P; Summers, Nathan; Israelite, Craig L

2013-12-01

Extensor mechanism disruption after total knee arthroplasty (TKA) is a complex problem that often requires surgical repair for functional deficits. We present a brief technical note on suture anchor fixation of a patellar tendon rupture after TKA. A surgical technique and literature review follows. Although suture anchor fixation is well described for tendinous repairs in other areas of orthopedic surgery, no study has discussed the use of suture anchors in patellar tendon repair after TKA. The technique must be evaluated in more patients with longer follow-up before adoption. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Do peak torque angles of muscles change following anterior cruciate ligament reconstruction using hamstring or patellar tendon graft?

PubMed

Yosmaoğlu, Hayri Baran; Baltacı, Gül; Sönmezer, Emel; Özer, Hamza; Doğan, Deha

2017-12-01

This study aims to compare the effects of anterior cruciate ligament (ACL) reconstruction using autogenous hamstring or patellar tendon graft on the peak torque angle. The study included 132 patients (103 males, 29 females; mean age 29±9 year) who were performed ACL reconstruction with autogenous hamstring or patellar tendon graft. The peak torque angles in the quadriceps and hamstring muscles were recorded using an isokinetic dynamometer. Angle of peak knee flexion torque occurred significantly earlier within the range of motion on the operated side than nonoperated side at 180°/second in the hamstring tendon group. Angle of peak knee extension torque occurred significantly earlier within the range of motion on the operated side than nonoperated side at 180°/second in the patellar tendon group. There were no statistically significant differences in the flexion and extension peak torque angles between the operated and nonoperated knees at 60°/second in both groups. The angle of peak torque at relatively high angular velocities is affected after ACL reconstruction in patients with hamstring or patellar tendon grafts. The graft donor site directly influences this parameter. This finding may be important for clinicians in terms of preventing re-injury.

Influence of Total Knee Arthroplasty on Patellar Kinematics and Patellofemoral Pressure.

PubMed

Tanikawa, Hidenori; Tada, Mitsunori; Harato, Kengo; Okuma, Kazunari; Nagura, Takeo

2017-01-01

Patellofemoral complications are one of the main problems after total knee arthroplasty (TKA). The design of the TKA component may affect the patellar biomechanics, which may be associated with this postoperative complication. The purpose of this study was to assess the influence of TKA and prosthesis designs on the patellar kinematics and patellofemoral pressure. Using fresh-frozen cadavers, we measured the patellofemoral pressure, patella offset, and patella tilt in the following 4 conditions: normal knee (patella replacement only), cruciate-retaining TKA, condylar-stabilizing TKA, and posterior-stabilized TKA. The patellofemoral pressure increased significantly after the cruciate-retaining TKA and condylar-stabilizing TKA compared with the normal knee. The patella offset in the normal knee decreased with increasing knee flexion angles, while the patella offset in the TKA knees did not change significantly through the full range of motion. The amount of lateral patella tilt in the normal knee was significantly larger than the TKA knees in the full range of motion. Although the femoral components are designed to reproduce an anatomical patellar tracking, the physiological patellar kinematics were not observed. Relatively high patellofemoral pressure and kinematic change after TKA may be associated with postoperative complications such as the anterior knee pain. Copyright © 2016 Elsevier Inc. All rights reserved.

Treatment of Patellar Lower Pole Fracture with Modified Titanium Cable Tension Band Plus Patellar Tibial Tunnel Steel "8" Reduction Band.

PubMed

Li, Jiaming; Wang, Decheng; He, Zhiliang; Shi, Hao

2018-01-08

To determine the efficacy of modified titanium tension band plus patellar tendon tunnel steel 8 "reduction band" versus titanium cable tension band fixation for the treatment of patellar lower pole fracture. 58 patients with lower patella fracture were enrolled in this study, including 30 patients treated with modified titanium cable tension band plus patellar tibial tunnel wire "8" tension band internal fixation (modified group), and 28 patients with titanium cable tension band fixation. All patients were followed up for 9∼15 months with an average of 11.6 months. Knee flexion was significantly improved in the modified group than in the titanium cable tension band group (111.33 ± 13 degrees versus 98.21 ± 21.70 degrees, P = 0.004). The fracture healing time showed no significant difference. At the end of the follow-up, the improvement excellent rate was 93.33% in the modified group, and 82.14% in the titanium cable tension band group. Titanium cable tension band internal fixation loosening was found in 2 cases, including 1 case of treatment by two surgeries without loose internal fixation. The modified titanium cable tension band with "8" tension band fixation showed better efficacy for lower patella fractures than titanium cable tension band fixation.

Impact of Patellar Tendinopathy on Knee Proprioception: A Cross-Sectional Study.

PubMed

Torres, Rui; Ferreira, João; Silva, Diogo; Rodrigues, Elisa; Bessa, Isabel M; Ribeiro, Fernando

2017-01-01

To determine whether high-level athletes with patellar tendinopathy have diminished knee proprioceptive acuity. Cross-sectional study. University research laboratory (institutional). Twenty-one basketball and volleyball players with patellar tendinopathy (13 men and 8 women; mean age 24.5 ± 3.6; body mass index = 22.5 ± 2.0 kg/m) and an equal number of athletes without symptoms of patellar tendinopathy injury were included in this study. Participants underwent knee proprioception assessments on a single day. Furthermore, age, sex, height, weight, VISA-P (Victorian Institute of Sport Assessment) questionnaire sports participation, medical history, knee injuries, previous treatment, and medication were obtained. Knee proprioception was evaluated by assessing sense of resistance, using a weight discrimination protocol, and joint position sense (JPS). No significant differences were observed in JPS at 30 and 60 degrees of knee flexion between groups (P = 0.165 and 0.481, respectively). In regard to the ability to discriminate weight, significant differences between the 2 groups were found with the tendinopathy group showing a higher percentage of error (P = 0.009), namely when the set of incremental weights varied by 10% from the standard weight. Athletes with patellar tendinopathy have a diminished perception of force signals required for weight discrimination, whereas JPS remains unaffected in these athletes.

Surgical repair of chronic patellar tendon rupture in total knee replacement with ipsilateral hamstring tendons.

PubMed

Spoliti, Marco; Giai Via, Alessio; Padulo, Johnny; Oliva, Francesco; Del Buono, Angelo; Maffulli, Nicola

2016-10-01

Patellar tendon rupture is a serious complication of total knee arthroplasty (TKA). Its reconstruction in patients with chronic ruptures is technically demanding. This article reports the results of surgical reconstruction of neglected patellar tendon rupture in TKA using autologous hamstring tendons. Nine TKA patients (six women and three men) (mean age at index surgery 68 years) with chronic patellar tendon tears underwent reconstruction with ipsilateral hamstrings tendon, leaving the distal insertion in situ. The clinical diagnosis was supported by imaging (anterior-posterior and 30° flexion lateral radiographs). Insall-Salvati index, range of motion, and leg extension test were recorded preoperatively and at last follow-up. The modified Cincinnati rating system and the Kujala score were administered. The patients sustained the patellar tendon tear an average of 8 weeks before the procedure. At final follow-up of 4 years (range 2-8 years), the median of extension lag was 5° (range 0°-15°; DS = 5). The median of post-operative Insall-Salvati index was 1.4 (range 1.3-1.8; SD = 0.15; p = 0.002) compared to the preoperative index of 1.7 (range 1.5-2.2; SD = 0.23). The mean modified Cincinnati and Kujala scores significantly increased compared with the preoperative ones (p < 0.01). At final follow-up, all patients were able to walk without brace or aids, and they were satisfied with the procedure. Based on our retrospective study of nine patients, reconstruction of neglected patellar tendon rupture in TKA with autologous hamstring tendons is feasible and safe, and provides good functional recovery. Case series, Level IV.

Patellofemoral Instability in Children: Correlation Between Risk Factors, Injury Patterns, and Severity of Cartilage Damage.

PubMed

Kim, Hee Kyung; Shiraj, Sahar; Kang, Chang Ho; Anton, Christopher; Kim, Dong Hoon; Horn, Paul S

2016-06-01

The purpose of this study was to compare MRI findings between groups with and without patellofemoral instability and to correlate the MRI findings with the severity of patellar cartilage damage. Fifty-three children with patellofemoral instability and 53 age- and sex-matched children without patellofemoral instability (15.9 ± 2.4 years) were included. Knee MRI with T2-weighted mapping was performed. On MR images, femoral trochlear dysplasia, patellofemoral malalignment, medial retinaculum injury, and bone marrow edema were documented. The degree of patellar cartilage damage was evaluated on MR images by use of a morphologic grading scale (0-4) and on T2 maps with mean T2 values at the medial, central, and lateral facets. MRI findings were compared between the two groups. In cases of patellofemoral instability, MRI findings were correlated with the severity of cartilage damage at each region. Trochlear structure and alignment were significantly different between the two groups (Wilcoxon p < 0.0001). In patellofemoral instability, a high-riding patella was associated with central patellar cartilage damage with a higher morphologic grade and T2 value (Spearman p < 0.05). The severity of medial retinacular injury and presence of bone marrow edema at either the medial patella or the lateral femoral condyle were associated with a higher grade of medial patellar cartilage damage (Wilcoxon p < 0.05). None of the other findings correlated with the severity of patellar cartilage damage. Patients with patellofemoral instability have significantly different trochlear structure and alignment than those who do not, and these differences are known risk factors for patellofemoral instability. However, the only risk factors or injury patterns that directly correlated with the severity of patellar cartilage damage were patella alta, medial stabilizer injury, and bone marrow edema.

Patellofemoral instability in children: T2 relaxation times of the patellar cartilage in patients with and without patellofemoral instability and correlation with morphological grading of cartilage damage.

PubMed

Kang, Chang Ho; Kim, Hee Kyung; Shiraj, Sahar; Anton, Christopher; Kim, Dong Hoon; Horn, Paul S

2016-07-01

Patellofemoral instability is one of the most common causes of cartilage damage in teenagers. To quantitatively evaluate the patellar cartilage in patients with patellofemoral instability using T2 relaxation time maps (T2 maps), compare the values to those in patients without patellofemoral instability and correlate them with morphological grades in patients with patellofemoral instability. Fifty-three patients with patellofemoral instability (mean age: 15.9 ± 2.4 years) and 53 age- and gender-matched patients without patellofemoral instability were included. Knee MR with axial T2 map was performed. Mean T2 relaxation times were obtained at the medial, central and lateral zones of the patellar cartilage and compared between the two groups. In the patellofemoral instability group, morphological grading of the patellar cartilage (0-4) was performed and correlated with T2 relaxation times. Mean T2 relaxation times were significantly longer in the group with patellofemoral instability as compared to those of the control group across the patellar cartilage (Student's t-test, P<0.05) with the longest time at the central area. Positive correlation was seen between mean T2 relaxation time and morphological grading (Pearson correlation coefficiency, P<0.001). T2 increased with severity of morphological grading from 0 to 3 (mixed model, P<0.001), but no statistical difference was seen between grades 3 and 4. In patellofemoral instability, patellar cartilage damage occurs across the entire cartilage with the highest T2 values at the apex. T2 relaxation times directly reflect the severity in low-grade cartilage damage, which implies an important role for T2 maps in differentiating between normal and low-grade cartilage damage.

Diagnostic Accuracy of a Self-Report Measure of Patellar Tendinopathy in Youth Basketball.

PubMed

Owoeye, Oluwatoyosi B A; Wiley, J Preston; Walker, Richard E A; Palacios-Derflingher, Luz; Emery, Carolyn A

2018-04-27

Study Design Prospective diagnostic accuracy validation study. Background Engaging clinicians for diagnosis of patellar tendinopathy in large surveillance studies is often impracticable. A self-report measure, the Oslo Sports Research Trauma Centre patellar tendinopathy (OSTRC-P) Questionnaire, an adaptation of the OSTRC Questionnaire may provide a viable alternative. Objectives To evaluate the diagnostic accuracy of the OSTRC-P Questionnaire in detecting patellar tendinopathy in youth basketball players when compared to clinical evaluation. Methods Following the Standards for Reporting of Diagnostic Accuracy Studies guidelines, 208 youth basketball players (aged 13-18 years) were recruited. Participants completed the OSTRC-P Questionnaire (index test) prior to a clinical evaluation (reference standard) by a physiotherapist blinded to OSTRC-P Questionnaire results. Sensitivity, specificity, predictive values (PVs), likelihood ratios (LRs) and posttest probabilities were calculated. Linear regression was used to examine the association between OSTRC-P Questionnaire severity score and patellar tendinopathy severity rating during single leg decline squat (SLDS). Results The final analysis included 169 players. The OSTRC-P Questionnaire had a sensitivity of 79% (95%CI: 65%, 90%), specificity of 98% (95%CI: 94%, 100%), positive PV of 95%, negative PV of 92%, positive LR of 48 and negative LR of 0.21. The posttest probabilities were 95% and 8% given positive and negative results, respectively. A positive association was found between OSTRC-P Questionnaire and SLDS rating [(β = .08 (95%CI: .03, .12) (p = .001)]. Conclusions The OSTRC-P Questionnaire is an acceptable alternative to clinical evaluation for self-reporting patellar tendinopathy and grading its severity in settings involving youth basketball players. Level of Evidence Diagnosis, level 1b. J Orthop Sports Phys Ther, Epub 27 Apr 2018. doi:10.2519/jospt.2018.8088.

Structural and in vivo mechanical characterization of canine patellar cartilage: a closed chondromalacia patellae model.

PubMed

LaBerge, M; Audet, J; Drouin, G; Rivard, C H

1993-01-01

The purpose of this project was to study the relationship between the structure of the patellar cartilage and its response to static compressive loading with a closed chondromalacia patellae model. An animal model was used to induce degeneration of the patella that was monitored quantitatively and qualitatively as a function of time. Ten adult mongrel dogs had their left patellofemoral groove replaced by a customized metallic implant covered with a thin film of polyethylene for periods of 3 months (five dogs) and 6 months (five dogs). An indenter was designed to perform mechanical indentation testing on the patellar cartilage in situ. The animals were anesthetized and the response of patellar cartilage to a static compressive load of 4.5 MPa was monitored for 20 min and its relaxation after load removal for 20 min. Indentation tests were performed every 3 months of the implantation period. At the end of the implantation period, the patellae were processed for histology, and sections were stained with Safranin-O indicative of the proteoglycans content. Macroscopically, no apparent degeneration or fibrillation of the patellar surfaces was observed after 3 or 6 months of implantation. However, the patellar surface showed a change in coloration after 6 months. A 17 +/- 3% and 37 +/- 8% deformation of the cartilage were calculated for the 3-month and 6-month specimens, respectively. Histologically, a progressive loss of proteoglycans was observed in the matrix as a function of implantation time. These results indicated that an increase in cartilage compliance is associated with an intrinsic remodeling of the cartilage matrix and that these changes might occur without external signs of degeneration and can be quantified.

The Relationship of Static Tibial Tubercle-Trochlear Groove Measurement and Dynamic Patellar Tracking.

PubMed

Carlson, Victor R; Sheehan, Frances T; Shen, Aricia; Yao, Lawrence; Jackson, Jennifer N; Boden, Barry P

2017-07-01

The tibial tubercle to trochlear groove (TT-TG) distance is used for screening patients with a variety of patellofemoral joint disorders to determine who may benefit from patellar medialization using a tibial tubercle osteotomy. Clinically, the TT-TG distance is predominately based on static imaging with the knee in full extension; however, the predictive ability of this measure for dynamic patellar tracking patterns is unknown. To determine whether the static TT-TG distance can predict dynamic lateral displacement of the patella. Cohort study (Diagnosis); Level of evidence, 2. The static TT-TG distance was measured at full extension for 70 skeletally mature subjects with (n = 32) and without (n = 38) patellofemoral pain. The dynamic patellar tracking patterns were assessed from approximately 45° to 0° of knee flexion by use of dynamic cine-phase contrast magnetic resonance imaging. For each subject, the value of dynamic lateral tracking corresponding to the exact knee angle measured in the static images for that subject was identified. Linear regression analysis determined the predictive ability of static TT-TG distance for dynamic patellar lateral displacement for each cohort. The static TT-TG distance measured with the knee in full extension cannot accurately predict dynamic lateral displacement of the patella. There was weak predictive ability among subjects with patellofemoral pain ( r 2 = 0.18, P = .02) and no predictive capability among controls. Among subjects with patellofemoral pain and static TT-TG distances 15 mm or more, 8 of 13 subjects (62%) demonstrated neutral or medial patellar tracking patterns. The static TT-TG distance cannot accurately predict dynamic lateral displacement of the patella. A large percentage of patients with patellofemoral pain and pathologically large TT-TG distances may have neutral to medial maltracking patterns.

The prevalence of Achilles and patellar tendon injuries in Australian football players beyond a time-loss definition.

PubMed

Docking, S I; Rio, E; Cook, J; Orchard, J W; Fortington, L V

2018-03-23

Little is known about the prevalence and associated of morbidity of tendon problems. With only severe cases of tendon problems missing games, players that have their training and performance impacted are not captured by traditional injury surveillance. The aim of this study was to report the prevalence of Achilles and patellar tendon problems in elite male Australian football players using the Oslo Sports Trauma Research Centre (OSTRC) overuse questionnaire, compared to a time-loss definition. Male athletes from 12 professional Australian football teams were invited to complete a monthly questionnaire over a 9-month period in the 2016 pre- and competitive season. The OSTRC overuse injury questionnaire was used to measure the prevalence and severity of Achilles and patellar tendon symptoms and was compared to traditional match-loss statistics. A total of 441 participants were included. Of all participants, 21.5% (95% CI: 17.9-25.6) and 25.2% (95% CI 21.3-29.4) reported Achilles or patellar tendon problems during the season, respectively. Based on the traditional match-loss definition, a combined 4.1% of participants missed games due to either Achilles or patellar tendon injury. A greater average monthly prevalence was observed during the pre-season compared to the competitive season. Achilles and patellar tendon problems are prevalent in elite male Australian football players. These injuries are not adequately captured using a traditional match-loss definition. Prevention of these injuries may be best targeted during the off- and pre-season due to higher prevalence of symptoms during the pre-season compared to during the competitive season. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Reconstruction of the extensor mechanism with fresh-frozen tendon allograft in total knee arthroplasty.

PubMed

Llombart Blanco, Rafael; Valentí, Andrés; Díaz de Rada, Pablo; Mora, Gonzalo; Valentí, Juan R

2014-11-01

Patellar tendon rupture after total knee replacement is a rare and highly limiting injury with multifactorial aetiology. Many reconstruction techniques have been described with not very predictable results. The use of allografts has been accepted as a suitable solution. A series of seven patients with patellar tendon rupture treated with fresh-frozen tendon allograft reconstruction after knee arthroplasty is presented. Median follow-up is 25 months (20-31). Functional assessment improved, and the knee society score and knee functional score improved from 26 and 16 to 82 and 55, respectively. Median extension lag was 5° (0°-20°), with a median range of motion of 95° (70-100). Radiological study showed a rise of the patella of 22.26 mm. The use of fresh-frozen allografts as a solution to patellar tendon ruptures after knee arthroplasty seems to provide acceptable results. Increased patellar height does not seem to affect functionality. Case series, Level IV.

Patellar Tendinopathy

PubMed Central

Schwartz, Aaron; Watson, Jonathan N.; Hutchinson, Mark R.

2015-01-01

Context: Patellar tendinopathy is a common condition. There are a wide variety of treatment options available, the majority of which are nonoperative. No consensus exists on the optimal method of treatment. Evidence Acquisition: PubMed spanning 1962-2014. Study Design: Clinical review. Level of Evidence: Level 4. Results: The majority of cases resolve with nonoperative therapy: rest, physical therapy with eccentric exercises, cryotherapy, anti-inflammatories, corticosteroid injections, extracorporeal shockwave therapy, glyceryl trinitrate, platelet-rich plasma injections, and ultrasound-guided sclerosis. Refractory cases may require either open or arthroscopic debridement of the patellar tendon. Corticosteroid injections provide short-term pain relief but increase risk of tendon rupture. Anti-inflammatories and injectable agents have shown mixed results. Surgical treatment is effective in many refractory cases unresponsive to nonoperative modalities. Conclusion: Physical therapy with an eccentric exercise program is the mainstay of treatment for patellar tendinopathy. Platelet-rich plasma has demonstrated mixed results; evidence-based recommendations on its efficacy cannot be made. In the event that nonoperative treatment fails, surgical intervention has produced good to excellent outcomes in the majority of patients. PMID:26502416

Plateau-patella angle in evaluation of patellar height after total knee arthroplasty.

PubMed

Robin, Brett N; Ellington, Matthew D; Jupiter, Daniel C; Allen, Bryce C

2014-07-01

The plateau-patella angle (PPA) has been proposed as a new and simpler method to describe patellar height. This method has not been used or validated in knees following total knee arthroplasty (TKA). A modified PPA (mPPA) was developed for use in this population. The method was validated by determining the interobserver and intraobserver reliability of the technique in 50 consecutive patients compared to three well-described methods of describing patellar height after TKA. Three observers then evaluated the mPPA of 297 post-operative radiographs to describe a normal range after TKA for a given technique and implant. The interobserver reliability was the highest for the mPPA compared to the other methods. The mean mPPA for the entire cohort was 21.06, 20.49, and 19.94 for the three observers. The modified plateau-patella angle is a reliable way to evaluate patellar height in patients who have undergone total knee arthroplasty. Copyright © 2014 Elsevier Inc. All rights reserved.

Adjustable patella grapple versus cannulated screw and cable technique for treatment of transverse patellar fractures.

PubMed

Yan, Ning; Yang, Anli; Liu, Xiaodong; Cai, Feng; Liu, Liang; Chang, Shimin

2014-03-01

Although the cannulated screw and cable (CSC) tension band technique is an effective method for fixation of transverse patellar fractures, it has shortcomings, such as extensive soft tissue damage, osseous substance damage, and complex manipulation. We conducted a retrospective comparison of the adjustable patella grapple (APG) technique and the CSC tension band technique. We retrospectively reviewed 78 patients with transverse patellar fractures (45 in the APG group and 33 in the CSC group). Follow-up was 18 months. Comparison criteria were operation time, fracture reduction, fracture healing time, the knee injury and osteoarthritis outcome score for knee function, and complications. The APG group showed shorter operation time and equal fracture reduction, fracture healing time, and knee function compared with the CSC group. Eleven patients in the APG group experienced skin irritation generated by implants. There was no complication in the CSC group. The APG technique should be considered as an alternative method for treatment of transverse patellar fractures.

Neovascularity in patellar tendinopathy and the response to eccentric training: a case report using Power Doppler ultrasound.

PubMed

McCreesh, Karen M; Riley, Sara J; Crotty, James M

2013-12-01

This report describes the case of an amateur soccer player with chronic patellar tendinopathy who underwent ultrasound imaging before and after engaging in an 8-week programme of eccentric exercise. On initial assessment, greyscale ultrasound imaging demonstrated tendon thickening and reduced echogenicity, while Power Doppler imaging demonstrated a large amount of neovascularity. After 8 weeks of an eccentric loading programme, the patient reported significantly improved symptoms and functional scores, while follow-up imaging demonstrated improvement in the echo appearance of the tendon and complete resolution of the neovascularity. The association between neovascularity and symptoms in tendinopathy research is conflicting, with a paucity of research in the area of patellar tendinopathy. While further research is needed to clarify the significance of greyscale and Power Doppler ultrasound changes in relation to symptoms in patellar tendinopathy, ultrasound imaging was shown to be a useful adjunct to diagnosis and outcome assessment in this case. Copyright © 2012 Elsevier Ltd. All rights reserved.

Endoscopic bursectomy for the treatment of septic pre-patellar bursitis: a case series.

PubMed

Dillon, John P; Freedman, Ilan; Tan, James S M; Mitchell, David; English, Shaun

2012-07-01

Operative treatment for septic pre-patellar bursitis generally involves open debridement in addition to an extended course of intravenous antibiotics. Skin necrosis and wound breakdown are potential complications of this procedure in addition to scar sensitivity and a prolonged recovery. We report endoscopic bursectomy for the treatment of septic pre-patellar bursitis in eight patients over a 3-year period. All patients had microbiological confirmation of an infective process. The average age was 36 years (23-68 years). The average hospital stay was 6 days (4-9 days). No patient had a recurrence or complained of tenderness or hypoaesthesia around their wound. No patient experienced wound complications or skin necrosis. The average return to work time was 18 days (7-22 days). We conclude that endoscopic bursectomy is a safe and effective treatment for septic pre-patellar bursitis with a shortened hospital stay and a quicker return to work than conventional open debridement.

Management of bilateral patellar luxation in an alpaca.

PubMed

Abuja, Gustavo A; Kowaleski, Michael P; García-López, José M

2014-05-01

To report surgical management bilateral lateral patellar luxation in a mature alpaca using a combination of trochlear wedge recession (TWR), tibial tuberosity transposition (TTT), and joint capsule imbrication. Clinical case report. 9-year-old castrated male Alpaca. Bilateral, grade III/IV, lateral patellar luxation was identified by palpation, lameness examination and confirmed with radiography and ultrasonography. Surgical procedures were staged, with the left stifle treated first. Bilateral TWR, TTT, and joint capsule imbrication were performed. Outcome was assessed by radiography and follow up lameness examinations. An immediate improvement in weight bearing occurred after surgery of the left hind limb. Five months after initial surgery, right hind limb patella luxation was corrected. After surgery on the 2nd limb, the alpaca had progressive improvement in weight bearing during hospitalization. At 12 months, there were no signs of lameness and the alpaca had resumed normal activities. For bilateral lateral patellar luxation, a combination of TWR, TTT, and joint capsule imbrication resulted in excellent long-term outcome. © Copyright 2014 by The American College of Veterinary Surgeons.

In-vivo patellar tracking in individuals with patellofemoral pain and healthy individuals.

PubMed

Esfandiarpour, Fateme; Lebrun, Constance M; Dhillon, Sukhvinder; Boulanger, Pierre

2018-02-28

Understanding of the exact cause of patellofemoral pain has been limited by methodological challenges to evaluate in-vivo joint motion. This study compared six degree-of-freedom patellar motion during a dynamic lunge task between individuals with patellofemoral pain and healthy individuals. Knee joints of eight females with patellofemoral pain and ten healthy females were imaged using a CT scanner in supine lying position, then by a dual-orthogonal fluoroscope while they performed a lunge. To quantify patellar motion, the three-dimensional models of the knee bones, reconstructed from CT scans, were registered on the fluoroscopy images using the Fluomotion registration software. At full knee extension, the patella was in a significantly laterally tilted (PFP: 11.77° ± 7.58° vs. healthy: 0.86° ± 4.90°; p = 0.002) and superiorly shifted (PFP: 17.49 ± 8.44 mm vs. healthy: 9.47 ± 6.16 mm, p = 0. 033) position in the patellofemoral pain group compared with the healthy group. There were also significant differences between the groups for patellar tilt at 45°, 60°, and 75° of knee flexion, and for superior-inferior shift of the patella at 30° flexion (p ≤ 0.031). In the non-weight-bearing knee extended position, the patella was in a significantly laterally tilted position in the patellofemoral pain group (7.44° ± 6.53°) compared with the healthy group (0.71° ± 4.99°). These findings suggest the critical role of passive and active patellar stabilizers as potential causative factors for patellar malalignment/maltracking. Future studies should investigate the associations between patellar kinematics with joint morphology, muscle activity, and tendon function in a same sample for a thorough understanding of the causes of patellofemoral pain. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

The effect of in situ freezing on rabbit patellar tendon. A histologic, biochemical, and biomechanical analysis

NASA Technical Reports Server (NTRS)

Graf, B. K.; Fujisaki, K.; Vanderby, R. Jr; Vailas, A. C.

1992-01-01

Cell necrosis has been well documented as one of the many changes that occur in autogenous tendon when it is used to reconstruct the anterior cruciate ligament. The purpose of this experiment was to isolate cell necrosis as a variable and study its effect on the patellar tendon. To accomplish this, both knees of 25 New Zealand White rabbits were operated on. In one knee, a 5-mm wide band of patellar tendon was subjected to two rapid freeze-thaw cycles, while the other knee underwent sham surgery. Histologic evaluation showed a zone of necrosis at 2 and 4 weeks with cellular repopulation complete at 8 weeks. patellar tendon cross-sectional area was 0.118 cm2 at 8 weeks for the frozen specimens compared to 0.102 cm2 for the sham-operated controls. This difference was significant at the P = 0.025 level. Mechanical testing at 4 and 8 weeks revealed no significant changes in tendon length, maximum load, or stiffness. The collagen content was also unchanged at both 4 and 8 weeks.

Basic kinematics and biomechanics of the patellofemoral joint part 2: the patella in total knee arthroplasty.

PubMed

Schindler, Oliver S

2012-02-01

Patellar and femoral component in total knee arthroplasty are inextricably linked as a functional unit. The configuration of this unit has been a matter of ongoing debate, and the myriad of different patellar and femoral components currently available reflect the lack of consensus with respect to the ideal design. One of the major challenges is to overcome the biomechanical disadvantages of a small contact area through which high contact pressures are transferred, making this mechanical construct the weakest part of the prosthetic knee. Contact areas are highly dependent on the congruency of the patellofemoral joint articulation, and are significantly smaller for dome shaped patellar components compared to those of more anatomic designs. However, when exposed to 3-dimensional movements, the contact areas of the dome shaped patella are significantly greater, indicating enhanced forgiveness regarding patellar malpositioning. Although contact stresses, a function of implant design and surface conformity, can reach levels far beyond the yield strength of UHMWPE, catastrophic failure of resurfaced patellar components, commonly seen in metal backed patellae, fashionable in the 1980s, has rarely been observed since. Although plastic deformation and wear of UHMWPE continue to represent a problem, in the absence of suitable alternatives polyethylene remains the bearing surface of choice. The appreciation of the consequences of the mechanical environment on the behaviour of the patellofemoral joint is of particular importance in the endeavour to develop knee replacement systems which provide satisfactory function together with clinical long-term success.

Does the grading of chondromalacia patellae influence anterior knee pain following total knee arthroplasty without patellar resurfacing?

PubMed

Zha, Guo-Chun; Feng, Shuo; Chen, Xiang-Yang; Guo, Kai-Jin

2018-03-01

The influence of chondromalacia patellae (CMP) on post-operative anterior knee pain (AKP) following total knee arthroplasty (TKA) remains controversial, and few studies have focused on the relationship between them. The purpose of this study was to determine whether different CMP grades affect the incidence of AKP after TKA without patellar resurfacing. We performed a retrospective analysis of prospectively collected data on 290 TKAs with the use of the low contact stress mobile-bearing prosthesis, without patellar resurfacing in 290 patients from February 2009 to January 2013. Patients were assessed by the Outerbridge classification for CMP, visual analog scale for AKP, the Knee Society clinical scoring system of knee score (KS), function score (FS), the patellar score (PS) for clinical function, and patients' satisfaction. The intra-operative grading of CMP: grade I in 30 patients, grade II in 68 patients, grade III in 97 patients, and grade IV in 95 patients. The incidence of AKP at 36-month follow-up was 10.3% (30/290). No statistical difference was detected among the different CMP grades in terms of the incidence of AKP (p = 0.995), patients' satisfaction (p = 0.832), KS (p = 0.228), FS (p = 0.713), and PS (p = 0.119) at 36-month follow-up. The findings may suggest no relevant influence of CMP grading on the incidence of AKP after TKA without patellar resurfacing.

Teaching enthesis ultrasound: experience of an ultrasound training workshop.

PubMed

Miguel, Cláudia; De Miguel, Eugenio; Batlle-Gualda, Enrique; Rejón, Eduardo; Lojo, Leticia

2012-12-01

To evaluate a standardised enthesis ultrasound training method, a workshop was conducted to train rheumatologists on enthesis ultrasound. After a theoretical session about ultrasound elementary enthesis lesions (changes in tendon architecture/thickness, bone proliferation/erosion, bursitis or Doppler signal), a reading exercise of 28 entheses' ultrasonographic images (plantar fasciae, Achilles, origin and insertion of patellar tendon) was completed. Participants scored through an electronic multiple-choice device with six possible lesions in each enthesis. To assess the adequacy and efficacy of the workshop, we explored the following: (1) subjective outcomes: a 12-item structured satisfaction questionnaire (graded 1-5 using Likert scale) and (2) objective outcomes of reliability: sensitivity (Se), specificity (Sp) and percentage of correctly classified cases (CC). Forty-nine participants attended the workshop. The satisfaction questionnaire demonstrated a 4.7 mean global value. The inter-reader Kappa reliability coefficient was moderate for the plantar fascia (0.47), Achilles tendon (0.47), and distal patellar tendons (0.50) and good for the proximal patellar tendon (0.63). The whole group means comparing to teachers' consensus were as follows: (a) plantar fascia: Se, 73.2%; Sp, 87.7%; CC, 83.3%; (b) Achilles: Se, 66.9%; Sp, 85.0%; CC, 79.5%; (c) distal patellar tendon: Se, 74.6%; Sp, 85.3%; CC, 82.1%; and (d) proximal patellar tendon: Se, 82.2%; Sp, 90.6%; CC, 88%. The proposed learning method seemed to be simple, easily performed, effective and well accepted by the target audience.

Efficacy of double inversion recovery magnetic resonance imaging for the evaluation of the synovium in the femoro-patellar joint without contrast enhancement.

PubMed

Son, Ye Na; Jin, Wook; Jahng, Geon-Ho; Cha, Jang Gyu; Park, Yong Sung; Yun, Seong Jong; Park, So Young; Park, Ji Seon; Ryu, Kyung Nam

2018-02-01

To investigate the efficacy of double inversion recovery (DIR) sequence for evaluating the synovium of the femoro-patellar joint without contrast enhancement (CE). Two radiologists independently evaluated the axial DIR and CE T1-weighted fat-saturated (CET1FS) images of 33 knees for agreement; the visualisation and distribution of the synovium were evaluated using a four-point visual scaling system at each of the five levels of the femoro-patellar joint and the location of the thickest synovium. The maximal synovial thickness at each sequence was measured by consensus. The interobserver agreement was good (κ = 0.736) for the four-point scale, and was excellent for the location of the thickest synovium on DIR and CET1FS (κ = 0.955 and 0.954). The intersequential agreement for the area with the thickest synovium was also excellent (κ = 0.845 and κ = 0.828). The synovial thickness on each sequence showed excellent correlation (r = 0.872). The DIR showed as good a correlation as CET1FS for the evaluation of the synovium at the femoro-patellar joint. DIR may be a useful MR technique for evaluating the synovium without CE. • DIR can be useful for evaluating the synovium of the femoro-patellar joint. • Interobserver and intersequential agreements between DIR and CET1FS were good. • Mean thickness of the synovium was significantly different between two sequences.

An Anatomic Study on Whether the Immature Patella is Centered on an Anteroposterior Radiograph.

PubMed

Kyriakedes, James C; Liu, Raymond W

2017-03-01

In the operating room, after first obtaining a proper lateral radiograph with the condyles superimposed, a 90-degree rotation of the intraoperative fluoroscopy unit does not always produce an anteroposterior (AP) image with the patella centered. The orthogonality of these 2 views has not been well determined in children. This study was comprised of a radiographic group (35 knees) and a cadaveric group (59 knees). Both cadaveric and clinical images were obtained by resting or positioning the femur with the posterior condyles overlapped, and then taking an orthogonal AP image. Centering of the patella was calculated and multiple regression analysis was performed to determine the relationship between patellar centering and age, sex, ethnicity, mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle (MPTA), and contralateral centering. Mean patellar centering, expressed as the lateral position of the patella with respect to the total condylar width, was 0.08±0.10 in the radiographic group and 0.06±0.03 in the cadaveric group. Positive (lateral) patellar centering in 1 knee had a statistically significant correlation with positive patellar centering in the contralateral knee in both the radiographs and the cadavers. In the radiographic group, there was a statistically significant correlation between femoral varus and valgus deformities and positive patellar centering. In the cadaveric group, there was a statistically significant correlation between tibial valgus and negative (medial) patellar centering. The patella in an immature knee is rarely perfectly centered on a true AP image, and is usually seated slightly laterally within the femoral condyles. Obtaining a true AP intraoperative radiograph is critical to analyzing and correcting valgus and varus deformities, and in the proper placement of implants. When addressing knee deformity one should consider obtaining an AP view orthogonal either to a perfect lateral of the knee or orthogonal to the flexion axis of the knee, particularly when evaluating distal femoral deformity.

T2 mapping in patellar chondromalacia.

PubMed

Ruiz Santiago, Fernando; Pozuelo Calvo, Rocío; Almansa López, Julio; Guzmán Álvarez, Luis; Castellano García, María Del Mar

2014-06-01

To study the correlation between the T2 relaxation times of the patellar cartilage and morphological MRI findings of chondromalacia. This prospective study comprises 50 patients, 27 men and 23 women suffering of anterior knee pain (mean age: 29.7, SD 8.3 years; range: 16-45 years). MRI of 97 knees were performed in these patients at 1.5T magnet including sagittal T1, coronal intermediate, axial intermediate fat sat and T2 mapping. Chondromalacia was assessed using a modified version of Noyes classification. The relaxation time, T2, was studied segmenting the full thickness of the patellar cartilage in 12 areas: 4 proximal (external facet-proximal-lateral (EPL), external facet-proximal-central (EPC), internal facet-proximal-central (IPC), internal facet-proximal-medial (IPM), 4 in the middle section (external facet-middle-lateral (EML), external facet-middle-central (EMC), internal facet-middle-central (IMC), internal facet-middle-medial (IMM) and 4 distal (external facet-distal-lateral (EDL), external facet-distal-central (EDC), internal facet-distal-central (IDC), internal facet-distal-medial (IDM). T2 values showed a significant increase in mild chondromalacia regarding normal cartilage in most of the cartilage areas (p<0.05), except in the internal distal facet (IDC and IDM), EPC, EDL, and IMM. Severe chondromalacia was characterized by a fall of T2 relaxation times with loss of statistical significant differences in comparison with normal cartilage, except in EMC and IMC, where similar values as mild chondromalacia were maintained (p<0.05). Steepest increase in T2 values of patellar cartilage occurs in early stages of patellar cartilage degeneration. Progression of morphologic changes of chondromalacia to more severe degrees is associated to a new drop of T2 relaxation times approaching basal values in most of the areas of the patellar cartilage, except in the central area of the middle section, where T2 values remain increased. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

[The initial (I and II) and advanced (III and IV) stages of juvenile patellar chondromalacia. Its diagnosis by magnetic resonance using a 1.5-T magnet with FLASH sequences].

PubMed

Macarini, L; Rizzo, A; Martino, F; Zaccheo, N; Angelelli, G; Rotondo, A

1998-06-01

Juvenile patellar chondromalacia is a common orthopedic disorder which can mimic other conditions; early diagnosis is mandatory to prevent its evolution into osteoarthrosis. In the early stages of patellar chondromalacia (I and II), the lesions originate in the deep cartilage layer and the joint surface is not affected. Arthroscopy can demonstrate joint surface changes only and give indirect information about deeper lesions. We investigated the yield of 2D FLASH MRI with 30 degrees flip angle and a dedicated coil in the diagnosis of patellar chondromalacia, especially in its early stages. Eighteen patients (mean age: 21 years) with clinically suspected patellar chondromalacia were examined with MRI; 13 of them were also submitted to arthroscopy. A 1.5 T unit with a transmit-and-receive extremity coil was used. We acquired T1 SE sequences (TR/TE: 500-700/15/20) and 2D T2* FLASH sequence (TR/TE/FA: 500-800/18/30 degrees). The field of view was 160-180 mm and the matrix 192 x 256, with 2-3 NEX. The images were obtained on the axial plane. The lesions were classified in 4 stages according to Shahriaree classification. Agreement between MR and arthroscopic findings was good in both early and advanced lesions in 12/13 cases. Early lesions appeared as hyperintense focal thickening of the hyaline cartilage (stage I) or as small cystic lesions within the cartilage and no articular surface involvement (stage II). The medial patellar facet was the most frequent site. Advanced lesions appeared as articular surface ulcerations, thinning and cartilage hypointensity (stage III); stage IV lesions presented as complete erosions of the hyaline cartilage and hypointense underlying bone. 2D FLASH MRI with 30 degrees flip angle can show the differences in water content in the cartilage and thus permit to detect early chondromalacia lesions in the deep cartilage.

Patellar Tendon Repair Augmentation With a Knotless Suture Anchor Internal Brace: A Biomechanical Cadaveric Study.

PubMed

Rothfeld, Alex; Pawlak, Amanda; Liebler, Stephenie A H; Morris, Michael; Paci, James M

2018-04-01

Patellar tendon repair with braided polyethylene suture alone is subject to knot slippage and failure. Several techniques to augment the primary repair have been described. Purpose/Hypothesis: The purpose was to evaluate a novel patellar tendon repair technique augmented with a knotless suture anchor internal brace with suture tape (SAIB). The hypothesis was that this technique would be biomechanically superior to a nonaugmented repair and equivalent to a standard augmentation with an 18-gauge steel wire. Controlled laboratory study. Midsubstance patellar tendon tears were created in 32 human cadaveric knees. Two comparison groups were created. Group 1 compared #2 supersuture repair without augmentation to #2 supersuture repair with SAIB augmentation. Group 2 compared #2 supersuture repair with an 18-gauge stainless steel cerclage wire augmentation to #2 supersuture repair with SAIB augmentation. The specimens were potted and biomechanically loaded on a materials testing machine. Yield load, maximum load, mode of failure, plastic displacement, elastic displacement, and total displacement were calculated for each sample. Standard statistical analysis was performed. There was a statistically significant increase in the mean ± SD yield load and maximum load in the SAIB augmentation group compared with supersuture alone (mean yield load: 646 ± 202 N vs 229 ± 60 N; mean maximum load: 868 ± 162 N vs 365 ± 54 N; P < .001). Group 2 showed no statistically significant differences between the augmented repairs (mean yield load: 495 ± 213 N vs 566 ± 172 N; P = .476; mean maximum load: 737 ± 210 N vs 697 ± 130 N; P = .721). Patellar tendon repair augmented with SAIB is biomechanically superior to repair without augmentation and is equivalent to repair with augmentation with an 18-gauge stainless steel cerclage wire. This novel patellar tendon repair augmentation is equivalent to standard 18-gauge wire augmentation at time zero. It does not require a second surgery for removal, and it is biomechanically superior to primary repair alone.

[Use of Ultrasound in the Follow-up of Professional Athletes Receiving Conservative Treatment of Patellar Tendon Enthesiopathy].

PubMed

Guo, Li-juan; Cui, Li-gang; Li, Yu-mei; Liao, Li-ping; Song, Lin

2015-10-01

To investigate the role of high-frequency ultrasound (HFUS) in evaluating in the effectiveness of conservative treatment for professional athletes with patellar tendon enthesiopathy. According to different treatment intensities, 24 professional athletes with patellar tendon enthesiopathy were randomly divided into painless group, slightly-painful group and extremely-painful group. Then changes of the HFUS findings [including ranges of two-dimensional diseases and blood conditions by Color Doppler Flow Imaging (CDFI)] of patellar tendon before and after the treatment were recorded. The results were also compared with conventional clinical treatment evaluations. After two courses of treatment,the percentage of athletes whose pain was resolved or disappeared was 37.5% in painless group, 87.5% in slightly-painful group, and 62.5% in extremely-painful group. The pain score was 4.50 ± 2.07, 4.88 ± 1.13, and 6.13 ± 1.55 in painless group,slightly-painful group,and extremely-painful group, respectively,before treatment and 4.88 ± 2.17, 3.00 ± 1.77,and 5.13 ± 2.36 after treatment. The average pain score remarkably decreased in the slightly-painful group and extremely-painful group,and such difference was statistically significant in the slightly-pain group (P<0.05). The effective rate (defined as thinner patellar,decreased hypoecho area and fewer blood distribution in the lesion) was 38%, 50%, and 62% in the painless group, slightly-painful group,and extremely-painful group, and the rates in the slightly-painful group and extremely-painful group were significantly higher than that in painless group (both P<0.05). HFUS can display the ultrasonographic changes of patellar tendon enthesiopathy after conservative treatments in an objective and quantitative manner. Compared with conventional clinical evaluations, it can more accurately reflect the disease recovery status.

Knee extensor dynamics in the volleyball approach jump: the influence of patellar tendinopathy.

PubMed

Sorenson, Shawn C; Arya, Shruti; Souza, Richard B; Pollard, Christine D; Salem, George J; Kulig, Kornelia

2010-09-01

Controlled laboratory study using a cross-sectional design. To evaluate knee joint dynamics in elite volleyball players with and without a history of patellar tendinopathy, focusing on mechanical energy absorption and generation. We hypothesized that tendinopathy would be associated withreduced net joint work and net joint power. Patellar tendinopathy is a common, debilitating injury affecting competitive volleyball players. Thirteen elite male players with and without a history of patellar tendinopathy (mean ± SD age, 27 ± 7 years) performed maximum-effort volleyball approach jumps. Sagittal plane knee joint kinematics, kinetics, and energetics were quantified in the lead limb, using data obtained from a force platform and an 8-camera motion analysis system. Vertical ground reaction forces and pelvis vertical velocity at takeoff were examined. Independent sample t tests were used to evaluate group differences (α = .05). The tendinopathy group, compared to controls, demonstrated significant reductions (approximately 30%) in net joint work and net joint power during the eccentric phase of the jump, with no differences in the concentric phase. Positive to-negative net joint work and net joint power ratios were significantly higher in the tendinopathy group, which had a net joint work ratio of 1.00 (95% CI: 0.77, 1.24) versus 0.76 (95% CI: 0.64, 0.88) for controls, and a net joint power ratio of 1.62 (95% CI: 1.15, 2.10) versus 1.00 (95% CI: 0.80, 1.21) for controls. There were no significant differences in net joint moment, angular velocity, or range of motion. Peak vertical ground reaction forces were lower for the tendinopathy group, while average vertical ground reaction forces and pelvis vertical velocity were similar. Patellar tendinopathy is associated with differences in sagittal plane mechanical energy absorption at the knee during maximum-effort volleyball approach jumps. Net joint work and net joint power may help define underlying mechanisms, adaptive effects, or rehabilitative strategies for individuals with patellar tendinopathy.

Lateral Patellar Instability in the Skeletally Mature Patient: Evaluation and Surgical Management.

PubMed

Diduch, David R; Kandil, Abdurrahman; Burrus, M Tyrrell

2018-05-18

Lateral patellar instability is a common disease process that affects all types of patients. Depending on the patient's anatomy and the results of preoperative imaging, surgical management options include medial patellofemoral ligament reconstruction, tibial tubercle osteotomy, and sulcus-deepening trochleoplasty. Medial patellofemoral ligament reconstruction or repair is useful for almost all patients, whereas tibial tubercle osteotomy is helpful to correct a lateralized tibial tubercle and the associated elevated lateral pull of the extensor mechanism. For a select subset of patients with severe trochlear dysplasia, a sulcus-deepening trochleoplasty can be a useful option to prevent future patellar instability. Many technical considerations exist for each procedure, and in most situations, no consensus exists to direct surgeons on the superior technique.

Chondromalacia induced by patellar subluxation: morphological and morphometrical aspects in rabbits.

PubMed

Sant'Anna, M M S; Apfel, M I R

2002-01-01

The purpose of this study was to describe morphologically and quantify the changes of the articular cartilage in chondromalacia, concerning both the chondrocytes and extracellular matrix. Eight rabbits were submitted daily to patellar subluxation, causing chondromalacia after two weeks. The knee fragments obtained were processed by the standard methods. These experimental conditions caused degenerative alterations of the articular cartilage, varying from a slight decrease of proteoglycans, to fibrillations, clefts, and horizontal splitting. The results showed a significantly increase number of chondrocytes (p < 0,000139), although smaller in size (p < 0,000109). The immobilization for 2 weeks and the intermittent passive daily motion afterwards for a period of 2 weeks, was effective to cause patellar chrondomalacia in rabbits.

“Basket weave technique” for medial patellofemoral ligament reconstruction: Clinical outcome of a prospective study

PubMed Central

Kodkani, Pranjal S

2016-01-01

Background: Bone tunneling and implants with rigid fixations for medial patellofemoral ligament (MPFL) reconstruction are known to compromise results and are avoidable, especially in skeletally immature subjects. This study was to assess if these deficiencies were overcome with the technique devised by the author which avoids implants and bone tunnels. Results were assessed for complication rate and outcome. Materials and Methods: Fifty six knees of recurrent lateral patellar dislocation were treated in the past 49 months by MPFL reconstruction. Thirty nine were female and 17 male knees. The mean age was 20.6 years (range 9-48 years). Mean followup was 26 months. Five knees had previously failed stabilization procedures. Thirty one cases had Dejours Type A or B and 12 had Type C trochlear dysplasia. Arthroscopy was performed for associated injuries and loose bodies. Seven knees required loose body removal. Five knees underwent lateral retinacular release. Four knees had tibial tuberosity transfer. One knee had an associated anterior cruciate ligament reconstruction. An anatomical MPFL reconstruction was performed using hamstring autograft without the need for intraoperative fluoroscopy. Only soft tissue fixation was necessary with this newly devised technique and suturing. A rapid rehabilitation protocol was implemented with monthly followup until normalcy and 6 monthly thereafter. Results: All achieved full range of motion and normal mediolateral stability. There was no recurrence of dislocation. No major surgery related complications. One patella fracture at 8 months was due to a fall developed terminal restriction of flexion. Those in sports could return to their sporting activities (Tegner 1–9). Cases with osteochondral fractures had occasional pain that subsided in 1 year. Mean Kujala score improved from 64.3 to 99.69 with KOOS score near normal in all. Conclusion: This new method of MPFL reconstruction gives excellent results. It avoids complications related to bone tunneling and implants. It is a safe, effective, reliable and reproducible technique. PMID:26952121

Impact of patellar height on unicompartment knee arthroplasty: does patella baja lead to an inferior outcome?

PubMed

Neogi, Devdatta Suhas; Bae, Ji Hoon; Seok, Chang Woo; Lim, Hong Chul

2014-03-01

Though a number of series with long-term results have been published, there is still a paucity of literature on the role of patellar height after unicompartment knee arthroplasty (UKA). The present study was conducted with a hypothesis that patella baja may lead to a poor outcome at follow-up. A retrospective review of 134 knees was performed and patellar height calculated before and after UKA by Blackburne-Peel index (BPI) and the Insall-Salvati ratio (ISR) on true lateral radiographs of the patients in 30° of flexion taken pre-operatively and at 1 year, 2 years and final follow-up (minimum 5 years). Statistical analysis was performed to evaluate the outcomes. There was a decrease in ISR in 14.18 % and in BPI in 19.4 % at final follow-up. There was a significant decrease in BPI values while the decrease was not significant for ISR. After eliminating the pre-operative patella baja, 7.3 % developed post-operative patella baja, according to ISR, while 11.5 % developed patella baja as per BPI. At final follow-up there was a statistically significant decrease in stair climbing scores in patients with patella baja when compared to patients with normal ISR. Patients with a decrease in patellar height as per ISR have a decrease in stair climbing score at mid-term follow-up while the overall KSS, and pain scores are not affected by a change in patellar height and neither is there a significant progress in patellofemoral osteoarthritis among patients with patella baja compared to normal patella.

Biomechanical analysis of the single‐leg decline squat

PubMed Central

Zwerver, J; Bredeweg, S W; Hof, A L

2007-01-01

Background The single‐leg squat on a 25° decline board has been described as a clinical assessment tool and as a rehabilitation exercise for patients with patellar tendinopathy. Several assumptions have been made about its working mechanism on patellar load and patellofemoral forces, but these are not substantiated by biomechanical evaluations. Aim To investigate knee moment and patellofemoral contact force as a function of decline angle in the single‐leg squat. Methods Five subjects performed single‐leg eccentric squats at decline angles of 0°, 5°, 10°, 15°, 20° and 25° (with/without a backpack of 10 kg), and 30° on a board that was placed over a forceplate. Kinematic and forceplate data were recorded by the Optotrak system. Joint moments of ankle, knee and hip were calculated by two‐dimensional inverse dynamics. Results Knee moment increased by 40% at decline angles of 15° and higher, whereas hip and ankle moment decreased. Maximum knee and ankle angles increased with steeper decline. With a 10 kg backpack at 25° decline, the knee moment was 23% higher than unloaded. Both patellar tendon and patellofemoral forces increased with higher decline angles, but beyond 60°, the patellofemoral force rose steeper than the tendon force. Conclusions All single‐leg squats at decline angles >15° result in 40% increase in maximum patellar tendon force. In knee flexions >60°, patellofemoral forces increase more than patellar tendon forces. Higher tendon load can be achieved by the use of a backpack with extra weight. PMID:17224441

Correlation between varus knee malalignment and patellofemoral osteoarthritis.

PubMed

Otsuki, Shuhei; Nakajima, Mikio; Okamoto, Yoshinori; Oda, Shuhei; Hoshiyama, Yoshiaki; Iida, Go; Neo, Masashi

2016-01-01

To evaluate the relationship between patellofemoral osteoarthritis (OA) and varus OA of the knee with a focus on the location of joint space narrowing. Eighty-five patients scheduled to undergo total knee arthroplasty caused by varus OA were enrolled in this study. The relationship between patellofemoral OA and varus knee malalignment was elucidated. To determine the alignment of the patellofemoral joint in varus knees, patellar tilt, and the tibial tuberosity-trochlear groove (TT-TG) distance were measured, and patellofemoral OA was classified using computed tomography. The femorotibial angles in patients with stage II-IV patellofemoral OA were significantly larger than those in patients with stage I patellofemoral OA, and the patellar tilt in patients with stage II-IV patellofemoral OA and the TT-TG distance in patients with stage IV patellofemoral OA were significantly larger than those in patients with stage I patellofemoral OA. The TT-TG distance was strongly correlated with patellar tilt (R(2) = 0.41, P < 0.001). Patellofemoral joint space narrowing was mainly noted at the lateral facet, and it was found on both sides as patellofemoral OA worsened. Varus knee malalignment was induced by patellofemoral OA, especially at the lateral facet. Patellar tilt and the TT-TG distance are considered critical factors for the severity of patellofemoral OA. Understanding the critical factors for patellofemoral OA in varus knees such as the TT-TG distance and patellar will facilitate the prevention of patellofemoral OA using procedures such as high tibial osteotomy and total knee arthroplasty to correct knee malalignment. Retrospective cohort study, Level III.

Does patellar rim electrocautery have deleterious effects on patellar cartilage?

PubMed

Namazi, Niloofar; Jaberi, Fereidoon Mojtahed; Pakbaz, Sara; Vosoughi, Amir Reza; Jaberi, Mahrad Mojtahed

2014-03-01

Circumpatellar electrocauterization to destroy pain receptors during total knee arthroplasty without patellar resurfacing is commonly used to decrease postoperative knee pain. We aimed to evaluate the effect of denervation with electrocauterization on patellar cartilage. Twenty rabbits were randomly assigned to two equally sized case and control groups. The rabbits in the case group underwent surgery via the anterior midline skin incision and medial parapatellar arthrotomy, followed by denervation electrocauterization at a depth of 1 mm and a distance of 3 mm from the outer border of the patella. In the control group, surgery was identical to that performed in the case group, but without patellar denervation. Twelve weeks after surgery, all rabbits were sacrificed. Range of motion, macroscopic evaluation of cartilage using modified Outerbridge scoring, and histopathological assessment using a modified histologic scoring system for cartilage were evaluated. Three rabbits died during the study. Nine cases and eight animals from the control group were included in the final evaluation. All rabbits had passive full range of motion. Mean Outerbridge score was 2.0 in the case group and 0.37 in the control group (p=0.002). There were statistically significant differences in cellularity (p=0.016), loss of matrix (p=0.004), and clustering of chondrocytes (p=0.008) between the two groups. Microscopic variables as a whole were statistically significant (p=0.001). Circumpatellar electrocauterization may result in cartilage destruction. So, we encourage caution in using routine electrocauterization in patients undergoing total knee arthroplasty. level II. Copyright © 2014 Elsevier B.V. All rights reserved.

Patellar position in weight-bearing radiographs compared with non-weight-bearing: significance for the detection of osteoarthritis.

PubMed

Skou, Nikolaj; Egund, Niels

2017-03-01

Background Diagnosis and treatment of patellofemoral disorders including osteoarthritis are currently often based on imaging and clinical assessment with patients in the supine position. Purpose To evaluate differences in patellar position in the trochlear groove and to assess the detection of medial and lateral patellofemoral (PF) osteoarthritis (OA) on axial radiographs in supine and standing positions, respectively. Material and Methods Thirty-five women and 23 men (mean age, 56 years; age range, 18-87 years) referred for routine radiographic examinations of the knees were included. Axial radiographs of the PF joint in both supine non-weight-bearing and standing weight-bearing position in 30° knee flexion were obtained of 111 knees. Measurements performed on the radiographs: patellar tilt, patellar displacement, joint space width, and grade of OA according to Ahlbäck. Results From supine to standing position the patella moved medially and medial joint space width and lateral patellar tilt angle decreased ( P < 0.0001 for the three measured parameters). In the standing position, medial PF OA was observed in 19 knees compared to three knees in the supine position. Fourteen knees had lateral PF OA with almost unchanged grade of OA irrespective of position. Conclusion In weight-bearing positions, the patella is positioned medially in the trochlear groove compared to supine non-weight-bearing positions. Therefore, this study suggests that the common occurrence of medial PF OA can generally not be detected on axial radiographs in supine non-weight-bearing positions and confirms the importance of imaging the PF joint in standing weight-bearing positions.

Prevalence and clinical significance of chondromalacia isolated to the anterior margin of the lateral femoral condyle as a component of patellofemoral disease: observations at MR imaging.

PubMed

Chan, V O; Moran, D E; Mwangi, I; Eustace, S J

2013-08-01

To determine the prevalence of chondromalacia isolated to the anterior margin of the lateral femoral condyle as a component of patellofemoral disease in patients with anterior knee pain and to correlate it with patient demographics, patellar shape, and patellofemoral alignment. Retrospective study over a 1-year period reviewing the MR knee examinations of all patients who were referred for assessment of anterior knee pain. Only patients with isolated lateral patellofemoral disease were included. Age, gender, distribution of lateral patellofemoral chondromalacia, and grade of cartilaginous defects were documented for each patient. Correlation between the distribution of lateral patellofemoral chondromalacia and patient demographics, patellar shape, and indices of patellar alignment (femoral sulcus angle and modified Q angle) was then ascertained. There were 50 patients (22 males, 28 females) with anterior knee pain and isolated patellofemoral disease. The majority of the patients (78 %) had co-existent disease with grade 1 chondromalacia. No significant correlation was found between patients with chondromalacia isolated to the anterior margin of the lateral femoral condyle and age, gender, patellar shape, or modified Q angle (p > 0.05). However, patients with chondromalacia isolated to the anterior margin of the lateral femoral condyle had a shallower femoral sulcus angle (mean 141.8°) compared to the patients with lateral patellar facet disease (mean 133.8°) (p = 0.002). A small percentage of patients with anterior knee pain have chondromalacia isolated to the anterior margin of the lateral femoral condyle. This was associated with a shallower femoral sulcus angle.

MRI quantitative morphologic analysis of patellofemoral region: lack of correlation with chondromalacia patellae at surgery.

PubMed

Endo, Yoshimi; Schweitzer, Mark E; Bordalo-Rodrigues, Marcelo; Rokito, Andrew S; Babb, James S

2007-11-01

In numerous studies, the morphologic features of the patellofemoral joint have been analyzed on radiographs. The objective of this study was to assess patellofemoral measurements on MR images and to correlate the measurements with the presence or absence of chondromalacia patellae confirmed at surgery. Axial and sagittal MR images of 98 knees (97 patients) were evaluated. Lateral and medial patellar facet lengths, lateral-to-medial facet length ratio, and interfacet angle were measured at three levels through the patella. Trochlear depth was measured on an axial slice. Patella and patellar tendon lengths, patellar tendon-to-patella ratio, and overlap of the patellar and trochlear articular cartilages were measured on sagittal slices. These measurements in knees with chondromalacia patellae were compared with those in knees without chondromalacia patellae. For assessment of reproducibility, axial measurements were repeated by a second observer. There was no statistically significant difference in any of the axial and sagittal slice measurements between knees with and those without chondromalacia patellae. Interobserver reliability was excellent for measurements of trochlear depth and measurements in the superior and middle aspects of the patella. Measurements through the inferior patella were slightly less reproducible. The results of our study with MRI confirmed many previous radiographic findings. Although we did not find correlation between the presence of chondromalacia patellae and the patellofemoral indexes we analyzed, it is possible that the results of further investigations incorporating different grades of chondromalacia and different locations along the patellar articular surface may lead to further insight regarding the morphologic risk factors for chondromalacia patellae.

Fresh-frozen Complete Extensor Mechanism Allograft versus Autograft Reconstruction in Rabbits

PubMed Central

Chen, Guanyin; Zhang, Hongtao; Ma, Qiong; Zhao, Jian; Zhang, Yinglong; Fan, Qingyu; Ma, Baoan

2016-01-01

Different clinical results have been reported in the repair of extensor mechanism disruption using fresh-frozen complete extensor mechanism (CEM) allograft, creating a need for a better understanding of fresh-frozen CME allograft reconstruction. Here, we perform histological and biomechanical analyses of fresh-frozen CEM allograft or autograft reconstruction in an in vivo rabbit model. Our histological results show complete incorporation of the quadriceps tendon into the host tissues, patellar survival and total integration of the allograft tibia, with relatively fewer osteocytes, into the host tibia. Vascularity and cellularity are reduced and delayed in the allograft but exhibit similar distributions to those in the autograft. The infrapatellar fat pad provides the main blood supply, and the lowest cellularity is observed in the patellar tendon close to the tibia in both the allograft and autograft. The biomechanical properties of the junction of quadriceps tendon and host tissues and those of the allograft patellar tendon are completely and considerably restored, respectively. Therefore, fresh-frozen CEM allograft reconstruction is viable, but the distal patellar tendon and the tibial block may be the weak links of the reconstruction. These findings provide new insight into the use of allograft in repairing disruption of the extensor mechanism. PMID:26911538

Fresh-frozen Complete Extensor Mechanism Allograft versus Autograft Reconstruction in Rabbits.

PubMed

Chen, Guanyin; Zhang, Hongtao; Ma, Qiong; Zhao, Jian; Zhang, Yinglong; Fan, Qingyu; Ma, Baoan

2016-02-25

Different clinical results have been reported in the repair of extensor mechanism disruption using fresh-frozen complete extensor mechanism (CEM) allograft, creating a need for a better understanding of fresh-frozen CME allograft reconstruction. Here, we perform histological and biomechanical analyses of fresh-frozen CEM allograft or autograft reconstruction in an in vivo rabbit model. Our histological results show complete incorporation of the quadriceps tendon into the host tissues, patellar survival and total integration of the allograft tibia, with relatively fewer osteocytes, into the host tibia. Vascularity and cellularity are reduced and delayed in the allograft but exhibit similar distributions to those in the autograft. The infrapatellar fat pad provides the main blood supply, and the lowest cellularity is observed in the patellar tendon close to the tibia in both the allograft and autograft. The biomechanical properties of the junction of quadriceps tendon and host tissues and those of the allograft patellar tendon are completely and considerably restored, respectively. Therefore, fresh-frozen CEM allograft reconstruction is viable, but the distal patellar tendon and the tibial block may be the weak links of the reconstruction. These findings provide new insight into the use of allograft in repairing disruption of the extensor mechanism.

[Histomorphological analyse of accelerating the fibrocartilage layer repair of patella-patellar tendon junction in rabbits by low intensity pulsed ultrasound stimulation].

PubMed

Zhang, Baoliang; Lü, Hongbin; Hu, Jianzhong; Xu, Daqi; Zhou, Jingyong; Wang, Ye

2013-08-01

To analyse the effect of low intensity pulsed ultrasound stimulation (LIPUS) on accelerating the fibrocartilage layer repair of patella-patellar tendon junction. A total of 60 mature female New Zealand white rabbits undergoing standard partial patellectomy were divided into 2 groups randomly. The control group was given comfort treatment and the treatment group was given LIPUS treatment starting from day 3 to the end of week 6 postoperatively. The scheduled time points of animal euthanization would be at week 6, week 12 and week 18 postoperatively. The patella-patellar tendon (PPT) complex would be harvested and cut into sections after decalcification for H&E staining, Safranine o/fast green staining. The thickness and gray value of fibrocartilage layer were analyzed by SANO Microscope Partner image analyzer. At week 6, week 12 and week 18 postoperatively, the fibrocartilage layer in the treatment group was significantly thicker than that in the control group (P<0.01), and the gray value of fibrocartilage layer was significantly smaller than that in the control group (P<0.01). LIPUS helps to accelerate the fibrocartilage layer repair of patella-patellar tendon junction in rabbit models.

[Simultaneous Traumatic Rupture of Patellar Ligament and Contralateral Rupture of Quadriceps Femoris Muscle].

PubMed

Hladký, V; Havlas, V

2017-01-01

Our paper presents a unique case of a 64-year-old patient after a fall, treated with oral antidiabetic drugs for type II diabetes mellitus. Following a series of examinations, a bilateral injury was diagnosed - patellar ligament tear on the right side and rupture of quadriceps femoris muscle on the left side. It is a rare injury, complicated by simultaneous involvement of both knee joints. The used therapy consisted of a bilateral surgery followed by gradual verticalisation, first with the support of a walking frame and later with the use of forearm crutches. During the final examination, the patient demonstrated full flexion at both knees, while an extension deficit of approx. 5 degrees was still present on the left side. The right knee X-ray showed a proper position of the patella after the removal of temporary tension band wire. Although the clinical results of operative treatment of both the patellar ligament rupture and rupture of quadriceps femoris muscle are in most cases good, early operative treatment, proper technique and post-operative rehabilitation are a prerequisite for success. Key words: knee injuries, patellar ligament, quadriceps muscle, rupture.

The chopstick-noodle twist: an easy technique of percutaneous patellar fixation in minimally displaced patellar fractures.

PubMed

Muzaffar, Nasir; Ahmad, Nawaz; Ahmad, Aejaz; Ahmad, Nissar

2012-01-01

We report six cases of minimally displaced two-part patellar fractures with skin injury over the patella that were treated with percutaneous K wire fixation and compression applied using stainless steel (SS) wire. This technique makes it possible to perform early operative treatment in cases where unhealthy skin is not amenable to conventional tension band wiring. The technique employs two K wires inserted through the two fracture fragments under local or regional anaesthesia. They are then compressed using simple SS wire knots at the two ends - making it look like noodles at the end of two chopsticks. The fixation is subsequently augmented with a cylindrical plaster-of-Paris cast. The technique is simple, cheap and does not cause soft tissue injury.

Acute traumatic rupture of the patellar tendon in pediatric population: Case series and review of the literature.

PubMed

Ali Yousef, Mohamed Abdelhamid; Rosenfeld, Scott

2017-11-01

Intact knee extensor mechanism is required for the normal function of the lower extremity. Patellar tendon rupture is a relatively rare injury with peak age incidence around 40 years and usually occurs midsubstance. The occurrence of pure patellar tendon rupture without bony avulsion is an extremely rare injury in the pediatric population with few cases reported in the literature with limited information regarding frequency, complications, and outcomes in children. However, due to increased participation in sports and high-energy recreational activities during childhood, the frequency of such injuries has progressively increased. To evaluate the frequency of pediatric patellar tendon rupture injuries and describe the radiological findings, treatment modalities, and outcome of such injuries. Demographic and clinical data on a series of patients who sustained patellar tendon rupture were reviewed. These data included age at time of injury, sex, laterality, mechanism of injury, associated injuries, complications, presence or absence of Osgood-Schlatter disease, diagnostic imaging such as plain radiographs and magnetic resonance images (MRI), surgical technique, method of fixation, period of postoperative immobilization, total duration of physiotherapy, time to return to sports activities and follow-up duration. Insall-Salvati ratio was calculated on the preoperative lateral x-ray. The functional outcome was evaluated with regard to final knee active range of motion (AROM), manual quadriceps muscle testing, and presence or the absence of terminal extension lag. Clinical outcome rating using knee society score (KSS) was performed and functional outcome was further classified according to the calculated score. Five male patients with patellar tendon rupture (7%) were identified among 71 pediatric patients who sustained acute traumatic injury of the knee extensor mechanism. The mean age at the time of injury was 13.6 years (range: 12-15 years). The injury occurred in relation to sports activities in 4 patients. Osteogenesis imperfecta and Osgood-Schlatter disease were identified in 2 patients. High riding patella is the hallmark diagnostic sign detected in plain x-ray with preoperative Insall-Salvati ratio ranged from 1.7 to 2.5. Three patients had pure soft tissue avulsion distally from the proximal tibia, 1 patient had pure soft tissue avulsion proximally from the inferior patellar pole, and 1 patient with midsubstance tendinous disruption. No associated intra-articular lesions were identified. Suture bridge double row technique, transpatellar suturing, and transosseous suturing through the proximal tibia were used for patellar tendon reinsertion. After a mean follow-up period of 18. 4 weeks (range: 10-30 weeks), patients achieved AROM ranging from 0 to 120° to 0-137° without terminal extension lag. The mean time to return to sports activity was 22 weeks (range: 13-30 weeks). Quadriceps muscle strength was 5/5 at the final follow-up visit in all patients; however, relative muscle atrophy was noted in comparison to the other side in one patient. The mean KSS was 91.8 points (range: 79-100 points) with excellent outcome in 4 patients and good outcome in 1 patient. Patellar tendon rupture is rare in the pediatric population and represents 7% of pediatric patients who sustained acute traumatic injury of the knee extensor mechanism. Ruptures may occur midsubstance, or from proximal or distal insertions. High riding patella is the hallmark diagnostic sign for such injury. Although rare, it is considered a serious injury that necessitates early diagnosis and surgical intervention. Functional range of motion was obtained in all patients with different modalities of treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bifocal osseous avulsion of the patellar tendon from the distal patella and tibial tuberosity in a child.

PubMed

Hermansen, Lars L; Freund, Knud G

2016-03-01

This case report describes a 12-year-old boy, who suffered an injury to the right knee in a skateboard accident. Radiographs and surgery confirmed the extremely rare bifocal avulsion fracture including the distal patellar pole and tibial tuberosity. Open reduction and internal fixation was accomplished, and 4-month follow-up demonstrated a good outcome.

Regeneration of Musculoskeletal Tissues by Prolonged Low-Grade Inflammation

DTIC Science & Technology

2011-10-01

grade inflammation around a pure collagen based scaffold on implantation into the rabbit patellar tendon. Additionally, the cross-sectional areas of...the tendons treated with the implant were about 40% greater compared to the sham- operated controls. In the current study, we hypothesized that soft...was implanted into the rat patellar tendon using a minimally invasive technique and the inflammation was blocked using liposomal clodronate. The

Influence of age on clinical outcomes of three-dimensional transfer of the tibial tuberosity for patellar instability with patella alta.

PubMed

Otsuki, Shuhei; Nakajima, Mikio; Fujiwara, Kenta; Okamoto, Yoshinori; Iida, Go; Murakami, Tomohiko; Neo, Masashi

2017-08-01

To evaluate the clinical outcomes of three-dimensional (3D) transfer of the tibial tuberosity for patellar instability with patella alta, with a focus on the influence of age at initial surgery. Three-dimensional surgery was performed on 28 knees with a mean follow-up of 46 months. Patients were separated into three groups based on the age at initial surgery: group A, 10 knees and an average age of 16.3 ± 1.8 (14-19) years; group B, 10 knees and an average age of 22.1 ± 2.5 (20-28) years; and group C, eight knees and an average age of 44.0 ± 2.2 (40-46) years. Patellofemoral geometry improvement focused on patella alta by determining the Insall-Salvati ratio and Caton-Deschamps index, rotational malalignment by measuring the tibial tubercle-trochlear groove (TT-TG) distance, and lateral patellar subluxation by measuring the patellar tilt. Clinical outcomes were evaluated by the Lysholm and Kujala scores, which were compared before and after surgery. Cartilage degeneration was evaluated by the International Cartilage Repair Society grading system at initial arthroscopy. The patellar height, TT-TG, and patellar tilt significantly improved in all groups postoperatively (p < 0.05). The Lysholm and Kujala scores also significantly improved postoperatively; however, both scores were lower in group C than in the other groups (p < 0.05). Particularly, pain scores were more severe in group C than in the other groups, and the severity of cartilage degeneration correlated with the pain scores (p < 0.05). Cartilage damage differed significantly between the groups at initial arthroscopy; particularly, group C included grades III and IV cartilage degeneration (p < 0.05). Age at initial surgery may be the predicting factor for poor clinical outcomes of 3D transfer surgery. The clinical outcome may depend on the age at surgery, which correlated with cartilage damage; thus, surgeons should be given this information when patients are considered undergoing patella surgery. Therapeutic case series, Level IV.

COMPARISON OF FUNCTIONAL ACTIVITIES ON STRUCTURAL CHANGES OF THE INFERIOR PATELLAR POLE

PubMed Central

Wallmann, Harvey; Stalcup, Patrick; DiTommaso, Katie

2017-01-01

Background It is well known that eccentric and concentric exercise produce varied amounts of stress on the connective tissues. Diagnostic ultrasound has been used to measure these structural changes by observing fascicle length, angle, and thickness; however, there is a lack of evidence comparing the structural changes as it relates to eccentric, concentric, and stretching protocols. Purpose The purpose of this study was to compare the acute effects of static stretching, eccentric, concentric, and a combination of eccentric/concentric exercises on structural changes of the muscle tendon unit at the inferior patellar pole utilizing the diagnostic ultrasound. Study Design A repeated measures 2 × 4 within factorial study design with repeated measures on both factors was used to determine the differences in patellar tendon thickness within and between groups. Methods Forty-seven healthy subjects were screened for any lower extremity deficits or orthopaedic pathology. Forty-four (N=44) subjects completed all four protocols; the attrition was due to injuries to the lower extremity, occurring unrelated to the study. A baseline measurement of the anterior inferior patellar tendon was performed with the diagnostic ultrasound prior to each participant completing one of the four interventions per week over a four-week period. Interventions completed by each participant included static stretching, concentric, eccentric, and combined concentric and eccentric exercises. Immediately following each intervention, a post-intervention inferior patellar tendon measurement was recorded using the diagnostic ultrasound. Results Significant differences in anterior to posterior tendon thickness of the inferior patellar tendon were observed between pre (4.983 ± 0.041mm) and post (5.198 ± 0.055mm) measurements (p<0.0005) for the main effect of time. However, no differences in tendon thickness were noted comparing each intervention to one another (p=0.351). Conclusion Differences in tendon thickness were noted acutely for pre- to post measurements across all interventions. Further research is needed to determine if differences in tendon thickness exist with a longer duration of exercise over time and with different types of intervention. PMID:29234561

Factors affecting the outcomes of modified tension band wiring techniques in transverse patellar fractures.

PubMed

Hsu, Kai-Lan; Chang, Wei-Lun; Yang, Chyun-Yu; Yeh, Ming-Long; Chang, Chih-Wei

2017-12-01

Modified tension band wiring has been widely used to treat transverse patellar fractures. However, few studies have evaluated the clinical outcomes using different methods of Kirschner wire bending, location of the tension band, and depths of Kirschner wires. Thus, we tried to clarify these factors according to our clinical outcomes. This retrospective cohort study recruited consecutive patients underwent surgical fixation for patellar fractures using modified tension band technique between January 2010 and December 2015. Different factors in this procedure, including the bending manner of the Kirschner wires, their depth, and location of the tension band with respect to the superior and inferior border of the patella were recorded and analysed. The primary outcome was early loss of fixation. The secondary outcomes were minor loss of reduction, implant breakage, deep infection, and the need for implant removal. This study included 170 patients with patellar fractures. Regarding the bending method, similar results were obtained with bilaterally or proximally bent Kirschner wires. Regarding length, the tension band was placed closely (within 25% of the patella length) in 124 patients and distantly in 46 patients. The rates of loss of reduction and implant breakage were significantly higher in the distantly placed tension bands. Regarding depth, 37 patellar fractures were fixed with the Kirschner wires at the superficial one third of the patellae while the K- wires at the middle layer of patella were used in the remaining 133 patellar fractures. A significantly higher rate of minor loss of reduction was obtained using the superficial Kirschner wires. The modified tension band technique for transverse patella fractures provides favourable clinical outcomes, with low failure (5%) and infection (2%) rates. Implant irritation is the major complication, and almost half of cases require implant removal. The location of the tension band with respect to the superior and inferior border of the patella plays an important role in clinical outcomes. Placing the wire close to the patella may prevent major loss of reduction and implant breakage. Superficially placed Kirschner wires also affect clinical outcomes by increasing the rate of minor loss of reduction. Copyright © 2017 Elsevier Ltd. All rights reserved.

Changes in Morphological and Elastic Properties of Patellar Tendon in Athletes with Unilateral Patellar Tendinopathy and Their Relationships with Pain and Functional Disability

PubMed Central

Zhang, Zhi Jie; Ng, Gabriel Yin-fat; Lee, Wai Chun; Fu, Siu Ngor

2014-01-01

Background Patellar tendinopathy (PT) is one of the most common knee disorders among athletes. Changes in morphology and elasticity of the painful tendon and how these relate to the self-perceived pain and dysfunction remain unclear. Objectives To compare the morphology and elastic properties of patellar tendons between athlete with and without unilateral PT and to examine its association with self-perceived pain and dysfunction. Methods In this cross-sectional study, 33 male athletes (20 healthy and 13 with unilateral PT) were enrolled. The morphology and elastic properties of the patellar tendon were assessed by the grey and elastography mode of supersonic shear imaging (SSI) technique while the intensity of pressure pain, self-perceived pain and dysfunction were quantified with a 10-lb force to the most painful site and the Victorian Institute of Sport Assessment-patella (VISA-P) questionnaire, respectively. Results In athletes with unilateral PT, the painful tendons had higher shear elastic modulus (SEM) and larger tendon than the non-painful side (p<0.05) or the dominant side of the healthy athletes (p<0.05). Significant correlations were found between tendon SEM ratio (SEM of painful over non-painful tendon) and the intensity of pressure pain (rho  = 0.62; p = 0.024), VISA-P scores (rho  = −0.61; p = 0.026), and the sub-scores of the VISA-P scores on going down stairs, lunge, single leg hopping and squatting (rho ranged from −0.63 to −0.67; p<0.05). Conclusions Athletes with unilateral PT had stiffer and larger tendon on the painful side than the non-painful side and the dominant side of healthy athletes. No significant differences on the patellar tendon morphology and elastic properties were detected between the dominant and non-dominant knees of the healthy control. The ratio of the SEM of painful to non-painful sides was associated with pain and dysfunction among athletes with unilateral PT. PMID:25303466

Superolateral Hoffa's Fat Pad Edema in Collegiate Volleyball Players.

PubMed

Mehta, Kaushal; Wissman, Robert; England, Eric; Dʼheurle, Albert; Newton, Keith; Kenter, Keith

2015-01-01

Superolateral Hoffa's fat pad (SHFP) edema is a previously described magnetic resonance (MR) finding located between the patellar tendon and the lateral femoral condyle. The purpose of our study was to determine the prevalence and clinical significance of SHFP edema in female collegiate volleyball players. Sixteen female collegiate volleyball players were consented for bilateral knee evaluations which consisted of history, physical examination and MR imaging. Each MR study was reviewed for the presence of SHFP edema, and 6 patellar maltracking measurements were done. These were tibial tuberosity-trochlear groove distance, patellar translation, lateral patellofemoral angle, trochlear depth, trochlear sulcus angle, and lateral trochlear inclination angle. A total of 16 athletes, 32 knees (16 girls; age range, 18-22 years; mean, 19.9) were enrolled in the study. Sixteen knees (50%) in 8 athletes had SHFP edema, with 100% bilaterality; 16 knees in 8 athletes had no evidence of SHFP edema (50%). Functional outcomes and physical examination findings were within normal limits for all athletes with no difference noted between SHFP edema-positive and -negative individuals. There was a statistically significant difference in the tibial tuberosity-trochlear groove distance, patellar translation, and patellofemoral angle (P value of < 0.001, 0.03 and 0.01, respectively) between the SHFP edema-positive and -negative individuals. Elite female volleyball athletes have a very high prevalence of SHFP edema, which is always bilateral. Although the exact etiology of SHFP edema remains inconclusive, it could potentially be a sensitive indicator of subtle patellar maltracking which cannot be distinguished by history and physical examination findings. Given the very high prevalence of SHFP edema and this being an asymptomatic finding, there is likely little clinical significance of this in majority of high-performance athletes.

The coupled effects of crouch gait and patella alta on tibiofemoral and patellofemoral cartilage loading in children.

PubMed

Brandon, Scott C E; Thelen, Darryl G; Smith, Colin R; Novacheck, Tom F; Schwartz, Michael H; Lenhart, Rachel L

2018-02-01

Elevated tibiofemoral and patellofemoral loading in children who exhibit crouch gait may contribute to skeletal deformities, pain, and cessation of walking ability. Surgical procedures used to treat crouch frequently correct knee extensor insufficiency by advancing the patella. However, there is little quantitative understanding of how the magnitudes of crouch and patellofemoral correction affect cartilage loading in gait. We used a computational musculoskeletal model to simulate the gait of twenty typically developing children and fifteen cerebral palsy patients who exhibited mild, moderate, and severe crouch. For each walking posture, we assessed the influence of patella alta and baja on tibiofemoral and patellofemoral cartilage contact. Tibiofemoral and patellofemoral contact pressures during the stance phase of normal gait averaged 2.2 and 1.0 MPa. Crouch gait increased pressure in both the tibofemoral (2.6-4.3 MPa) and patellofemoral (1.8-3.3 MPa) joints, while also shifting tibiofemoral contact to the posterior tibial plateau. For extended-knee postures, normal patellar positions (Insall-Salvatti ratio 0.8-1.2) concentrated contact on the middle third of the patellar cartilage. However, in flexed knee postures, both normal and baja patellar positions shifted pressure toward the superior edge of the patella. Moving the patella into alta restored pressure to the middle region of the patellar cartilage as crouch increased. This work illustrates the potential to dramatically reduce tibiofemoral and patellofemoral cartilage loading by surgically correcting crouch gait, and highlights the interaction between patella position and knee posture in modulating the location of patellar contact during functional activities. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantitative assessment of patellar vascularity following bone-patellar tendon-bone autograft harvest for ACL reconstruction.

PubMed

Jones, Kristofer J; Lazaro, Lionel E; Taylor, Samuel A; Pardee, Nadine C; Dyke, Jonathan P; Hannafin, Jo A; Warren, Russell F; Lorich, Dean G

2016-09-01

Recent anatomic studies have suggested that the dominant arterial supply of the patella enters through the inferior pole. Based upon these findings, we hypothesized that bone-patellar tendon-bone graft harvest can significantly diminish patellar vascularity. Nine matched pair cadaveric knee specimens (mean age 47.4 years) were dissected and cannulated. A single knee was selected to undergo routine graft harvest, and the contralateral knee was left intact to serve as a control. Gadolinium was injected, and magnetic resonance imaging (MRI) signal enhancement was quantified to determine differences in uptake. Each matched pair was subsequently injected with a urethane polymer compound and dissected to correlate vessel disruption with MRI findings. We identified two predominating patterns of vessel entry. In one pattern, the vessel entered the inferomedial aspect (five o'clock/right, seven o'clock/left) of the patella and was disrupted by graft harvest in 2/9 (22.2 %) pairs. In the second pattern, the vessel entered further medial (four o'clock/right, eight o'clock/left) and was not disrupted (7/9, 78.8 %). The mean decrease in gadolinium uptake following disruption of the predominant vessel measured 56.2 % (range 42.6-69.5 %) compared to an average decrease of 18.3 % (range 7.1-29.1 %) when the dominant arterial supply to the inferior pole remained intact (p < 0.04). Medial entry of the predominant vessel precluded vessel disruption. Disruption of the dominant arterial supply can result in a significant decrease in patellar vascularity. Modification of graft harvest techniques and areas of surgical dissection should be explored to minimize vascular insult. Further correlation with clinical studies/outcomes is necessary to determine a potential association between vascular insult and anterior knee pain.

Open versus closed kinetic chain exercises for patellar chondromalacia.

PubMed

Bakhtiary, A H; Fatemi, E

2008-02-01

Conservative treatment of patellar chondromalacia has been the subject of several studies. One recommended treatment is a strengthening exercise of the quadriceps muscle, which may be performed in closed or open kinetic chains. This study was designed to compare the effect of straight leg raise (SLR) and semi-squat exercises on the treatment of patellar chondromalacia, which has not been done to date. 32 female university students with a diagnosis of patellar chondromalacia were randomly assigned to two experimental groups: SLR and semi-squat exercise. Before starting exercise protocols, Q angle, maximal isometric voluntary contraction force (MIVCF) of quadriceps, crepitation, circumference of thigh 5 and 10 cm above the patella and patellofemoral pain according to the visual analogue scale (VAS) were assessed. Both groups then followed a 3-week programme of quadriceps muscle strengthening exercises (SLR or semi-squat) starting with 20 exercises twice a day and increasing each session by 5 exercises every 2 days. All measurements were repeated at the end of each week and then again 2 weeks after the 3-week exercise programme. Reduced Q angle (mean differences (SD) 0.8 (0.3), p = 0.016) and crepitation (19.9 (8.5), p = 0.04), and an increase in the MIVCF of the quadriceps (15.8 (5.6), p = 0.01) and thigh circumference (1.5 (0.3), p = 0.001) were found in semi-squat group compared with SLR group. However, patellofemoral pain was decreased significantly in both groups. The results of this study indicate that semi-squat exercises (closed kinetic chain) are more effective than SLR exercise (open kinetic chain) in the treatment of patellar chondromalacia. More studies are needed to investigate the long-term effect of these types of exercise.

Patellar cartilage lesions: comparison of magnetic resonance imaging and T2 relaxation-time mapping.

PubMed

Hannila, I; Nieminen, M T; Rauvala, E; Tervonen, O; Ojala, R

2007-05-01

To evaluate the detection and the size of focal patellar cartilage lesions in T2 mapping as compared to standard clinical magnetic resonance imaging (MRI) at 1.5T. Fifty-five consecutive clinical patients referred to knee MRI were imaged both with a standard knee MRI protocol (proton-density-weighted sagittal and axial series, T2-weighted sagittal and coronal series, and T1-weighted coronal series) and with an axial multislice multi-echo spin-echo measurement to determine the T2 relaxation time of the patellar cartilage. MR images and T2 maps of patellar cartilage were evaluated for focal lesions. The lesions were evaluated for lesion width (mm), lesion depth (1/3, 2/3, or 3/3 of cartilage thickness), and T2 value (20-40 ms, 40-60 ms, or 60-80 ms) based on visual evaluation. Altogether, 36 focal patellar cartilage lesions were detected from 20 human subjects (11 male, nine female, mean age 40+/-15 years). Twenty-eight lesions were detected both on MRI and T2 maps, while eight lesions were only visible on T2 maps. Cartilage lesions were significantly wider (P = 0.001) and thicker (P<0.001) on T2 maps as compared to standard knee MRI. Most lesions 27 had moderately (T2 40-60 ms) increased T2 values, while two lesions had slightly (T2 20-40 ms) and seven lesions remarkably (T2 60-80 ms) increased T2 relaxation times. T2 mapping of articular cartilage is feasible in the clinical setting and may reveal early cartilage lesions not visible with standard clinical MRI.

Does patella lowering improve crouch gait in cerebral palsy? Comparative retrospective study.

PubMed

Desailly, E; Thévenin-Lemoine, C; Khouri, N

2017-09-01

Patella lowering aims to improve quadriceps function as a means of correcting crouch gait in patients with cerebral palsy. Few studies have assessed the effects of patella lowering as a component of multilevel surgery. Including patella lowering into the components of multilevel surgery is beneficial in patients with crouch gait and patella alta. In 12 lower limbs with patella alta (Caton-Deschamps index>1.4) in 41 children with cerebral palsy, patella lowering was performed, without distal femoral extension osteotomy or hamstring release. Among limbs with similar surgical procedures (e.g., hamstring lengthening, rectus femoris transfer) except for patella lowering, controls were selected retrospectively by matching on a propensity score for patella lowering. The propensity score was computed based on preoperative knee flexion contracture, knee extension lag, and minimum knee flexion at mid-stance. Clinical and 3D kinematic data were compared between the two groups. The improvement in minimum knee flexion at mid-stance was significantly greater in the group with patellar lowering (-24°±12°vs. -12°±7°). The Gait Deviation Index improved similarly in the two groups. Knee flexion contracture improved only in the group with patellar lowering. Extension lag did not improve in either group. Peak knee flexion during the swing phase remained unchanged in both groups. Patellar lowering is effective in diminishing minimum knee flexion at mid-stance in patients with patella alta and crouch gait due to cerebral palsy. Patellar lowering has not adverse effects on gait. These findings cannot be assumed to apply to patients with normal patellar height. IV (retrospective study). Copyright © 2017. Published by Elsevier Masson SAS.

Cross-cultural adaptation of VISA-P score for patellar tendinopathy in Turkish population.

PubMed

Çelebi, Mehmet Mesut; Köse, Serdal Kenan; Akkaya, Zehra; Zergeroglu, Ali Murat

2016-01-01

VISA-P questionnaire assesses to severity of symptoms and treatment effects in athletes with patellar tendinopathy. The purpose of this study was to translated VISA-P questionnaire into Turkish language and to determine its validity and reliability. The English version of VISA-P questionnaire was translated into Turkish according to the internationally recommended guidelines. Test-retest reliability was determined on 89 participants with time interval 24 h. To determine validity of Turkish VISA-P, 31 (17 male, 14 female) healthy students, 34 (20 male, 14 female) patients with patellar tendinopathy (diagnosed by physical examination and ultrasonography) and 24 (16 male, 8 female) volleyball players (at risk populations) were completed VISA-P-Tr. Internal consistency was determined with Cronbach's alpha. Intraclass correlation coefficients (ICCs) were calculated to analyse test-retest reliability. To assessment of discrimination, VISA-P-Tr scores compared all groups using the Mann-Whitney-U test. The VISA-P-Tr questionnaire showed good test-retest reliability (The Cronbach's alpha was 0.79 and 0.78 respectively and ICC was 0.96). The VISA-P-Tr score (mean ± SD) were 93.7 ± 8.9 and 94.0 ± 8.1 for healthy students, 81.1 ± 13.7 and 80.7 ± 13.4 for volleyball players, 58.8 ± 12.1 and 58.5 ± 11.0 for athletes with patellar tendinopathy. The translated Turkish version of VISA-P has good internal consistency and good reliability and validity. Therefore VISA-P-Tr is useful to evaluate symptoms and follow the treatment effect in athletes with patellar tendinopathy.

Reliability of McConnell's classification of patellar orientation in symptomatic and asymptomatic subjects.

PubMed

Watson, C J; Propps, M; Galt, W; Redding, A; Dobbs, D

1999-07-01

Test-retest reliability study with blinded testers. To determine the intratester reliability of the McConnell classification system and to determine whether the intertester reliability of this system would be improved by one-on-one training of the testers, increasing the variability and numbers of subjects, blinding the testers to the absence or presence of patellofemoral pain syndrome, and adhering to the McConnell classification system as it is taught in the "McConnell Patellofemoral Treatment Plan" continuing education course. The McConnell classification system is currently used by physical therapy clinicians to quantify static patellar orientation. The measurements generated from this system purportedly guide the therapist in the application of patellofemoral tape and in assessment of the efficacy of treatment interventions on changing patellar orientation. Fifty-six subjects (age range, 21-65 years) provided a total of 101 knees for assessment. Seventy-six knees did not produce symptoms. A researcher who did not participate in the measuring process determined that 17 subjects had patellofemoral pain syndrome in 25 knees. Two testers concurrently measured static patellar orientation (anterior/posterior and medial/lateral tilt, medial/lateral glide, and patellar rotation) on subjects, using the McConnell classification system. Repeat measures were performed 3-7 days later. A kappa (kappa) statistic was used to assess the degree of agreement within each tester and between testers. The kappa coefficients for intratester reliability varied from -0.06 to 0.35. Intertester reliability ranged from -0.03 to 0.19. The McConnell classification system, in its current form, does not appear to be very reliable. Intratester reliability ranged from poor to fair, and intertester reliability was poor to slight. This system should not be used as a measurement tool or as a basis for treatment decisions.

Editorial Commentary: Which Came First, the Patella or the Trochlea? Morphological Relationships in Patients With Patellar Instability.

PubMed

Tanaka, Miho J

2018-06-01

Trochlear dysplasia and patella alta are known risk factors for patellar instability, yet the relation between the two has not been well understood. Morphologic abnormalities such as trochlear dysplasia and patella alta are known to alter patellofemoral kinematics, whereas altered contact pressures, in turn, have been associated with the development of trochlear dysplasia. As our current treatments aim to correct these deformities through increasingly complex procedures such as trochleoplasty and tuberosity distalization, we should consider this relation and the potential for changing the course of developing such morphologic abnormalities earlier in life. Further studies on the developmental cause of this disorder may help guide future treatments in the management of patellar instability. Copyright © 2018 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Tibial Tubercle Osteotomies: a Review of a Treatment for Recurrent Patellar Instability.

PubMed

Grimm, Nathan L; Lazarides, Alexander L; Amendola, Annunziato

2018-06-01

The goal of this review is to provide an overview of current surgical treatment options for tibial tubercle osteotomies as a treatment for recurrent patellofemoral instability. As such we sought to provide the reader with the most current answers to why treatment practices have changed and how this has affected the outcome of surgical treatment for patellar instability. As our understanding of patellofemoral biomechanics have grown, appropriate surgical and non-surgical treatment options have followed suit to address these findings. A clear understanding of the pathomechanics causing the patient's patellar instability is germane to choosing the most appropriate surgical intervention to address this instability. Likewise, understanding the goal of the intervention chosen-e.g., unloading, realignment-is paramount. These surgical techniques may be technically challenging and surgical specialists with experience in these techniques are recommended for optimal outcomes.

Adaptation of bone and tendon to prolonged hindlimb suspension in rats

NASA Technical Reports Server (NTRS)

Vailas, Arthur C.; Deluna, Diane M.; Lewis, Lisa L.; Curwin, Sandra L.; Roy, Roland R.

1988-01-01

The effect of a sustained deprivation of ground reaction forces on mineralized and soft connective tissues was investigated in rats subjected to 28-d-long hind-limb suspension. The results of morphological and biochemical studies carried out on femurs and patellar tendons obtained from suspended and nonsuspended 110-d-old rats showed that prolonged suspension led to an increase of the minimum diameter of the femur middiaphysis (by 12 percent), without any significant alterations in cortical area, density, mineral and collagen concentrations, femur wet weight, length, and DNA and uronic acid concentrations. However, in the patellar tendons of suspended rats, the collagen and proteoglycan concentrations were 28 percent lower than in tendons obtained from nonsuspended animals. These results suggest that ground reaction forces are important for the maintenance of cortical bone and patellar tendon homeostasis during weight-bearing conditions.

Avulsion fracture of the posterior cruciate ligament in an uncommon location associated with distal injury to the patellar ligament☆

PubMed Central

e Albuquerque, Rodrigo Pires; da Palma, Idemar Monteiro; Cobra, Hugo; de Paula Mozella, Alan; Vaques, Victor

2015-01-01

Avulsion fractures of the posterior cruciate ligament in unusual locations are rare injuries. We report the first case in the literature of an avulsion fracture of the posterior cruciate ligament associated with distal injury to the patellar ligament. The aim of this study was to present a novel case, the therapy used and the clinical follow-up. PMID:27218089

Rehabilitation protocol for patellar tendinopathy applied among 16- to 19-year old volleyball players.

PubMed

Biernat, Ryszard; Trzaskoma, Zbigniew; Trzaskoma, Lukasz; Czaprowski, Dariusz

2014-01-01

The aim of the study was to investigate the efficacy of rehabilitation protocol applied during competitive period for the treatment of patellar tendinopathy. A total of 28 male volleyball players were divided into two groups. Fifteen from experimental group (E) and 13 from control group (C) fulfilled the same tests 3 times: before the training program started (first measurement), after 12 weeks (second measurement) and after 24 weeks (third measurement). The above-mentioned protocol included the following: USG imagining with color Doppler function, clinical testing, pain intensity evaluation with VISA-P questionnaire, leg muscle strength and power and jumping ability measurements. The key element of the rehabilitation program was eccentric squat on decline board with additional unstable surface. The essential factor of the protocol was a set of preventive functional exercises, with focus on eccentric exercises of hamstrings. Patellar tendinopathy was observed in 18% of the tested young volleyball players. Implementation of the presented rehabilitation protocol with eccentric squat on decline board applied during sports season lowered the pain level of the young volleyball players. Presented rehabilitation protocol applied without interrupting the competitive period among young volleyball players together with functional exercises could be an effective method for the treatment of patellar tendinopathy.

Patellar denervation with electrocautery in total knee arthroplasty without patellar resurfacing: a meta-analysis.

PubMed

Cheng, Tao; Zhu, Chen; Guo, Yongyuan; Shi, Sifeng; Chen, Desheng; Zhang, Xianlong

2014-11-01

The impact of patellar denervation with electrocautery in total knee arthroplasty (TKA) on post-operative outcomes has been under debate. This study aims to conduct a meta-analysis and systematic review to compare the benefits and risks of circumpatellar electrocautery with those of non-electrocautery in primary TKAs. Comparative and randomized clinical studies were identified by conducting an electronic search of articles dated up to September 2012 in PubMed, EMBASE, Scopus, and the Cochrane databases. Six studies that focus on a total of 849 knees were analysed. A random-effects model was conducted using the inverse-variance method for continuous variables and the Mantel-Haenszel method for dichotomous variables. There was no significant difference in the incidence of anterior knee pain between the electrocautery and non-electrocautery groups. In term of patellar score and Knee Society Score, circumpatellar electrocautery improved clinical outcomes compared with non-electrocautery in TKAs. The statistical differences were in favour of the electrocautery group but have minimal clinical significance. In addition, the overall complications indicate no statistical significance between the two groups. This study shows no strong evidence either for or against electrocautery compared with non-electrocautery in TKAs. Therapeutic study (systematic review and meta-analysis), Level III.

Physical therapists' role in prevention and management of patellar tendinopathy injuries in youth, collegiate, and middle-aged indoor volleyball athletes

PubMed Central

Kulig, Kornelia; Noceti-DeWit, Lisa M.; Reischl, Stephen F.; Landel, Rob F.

2015-01-01

Patellar tendinopathy is highly prevalent in all ages and skill levels of volleyball athletes. To illustrate this, we discuss the clinical, biomechanical, and ultrasound imaging presentation and the intervention strategies of three volleyball athletes at different stages of their athletic career: youth, middle-aged, and collegiate. We present our examination strategies and interpret the data collected, including visual movement analysis and dynamics, relating these findings to the probable causes of their pain and dysfunction. Using the framework of the EdUReP concept, incorporating Education, Unloading, Reloading, and Prevention, we propose intervention strategies that target each athlete's specific issues in terms of education, rehabilitation, training, and return to sport. This framework can be generalized to manage patellar tendinopathy in other sports requiring jumping, from youth to middle age, and from recreational to elite competitive levels. PMID:26537811

Semiextended approach for intramedullary nailing via a patellar eversion technique for tibial-shaft fractures: Evaluation of the patellofemoral joint.

PubMed

Yasuda, Tomohiro; Obara, Shu; Hayashi, Junji; Arai, Masayuki; Sato, Kaoru

2017-06-01

Intramedullary nail fixation is a common treatment for tibial-shaft fractures, and it offers a better functional prognosis than other conservative treatments. Currently, the primary approach employed during intramedullary nail insertion is the semiextended position is the suprapatellar approach, which involves a vertical incision of the quadriceps tendon Damage to the patellofemoral joint cartilage has been highlighted as a drawback associated with this approach. To avoid this issue, we perform surgery using the patellar eversion technique and a soft sleeve. This method allows the articular surface to be monitored during intramedullary nail insertion. We arthroscopically assessed the effect of this technique on patellofemoral joint cartilage. The patellar eversion technique allows a direct view and protection of the patellofemoral joint without affecting the patella. Thus, damage to the patellofemoral joint cartilage can be avoided. Copyright © 2017 Elsevier Ltd. All rights reserved.

Association between patellar cartilage defects and patellofemoral geometry: a matched-pair MRI comparison of patients with and without isolated patellar cartilage defects.

PubMed

Mehl, Julian; Feucht, Matthias J; Bode, Gerrit; Dovi-Akue, David; Südkamp, Norbert P; Niemeyer, Philipp

2016-03-01

To compare the geometry of the patellofemoral joint on magnetic resonance images (MRI) between patients with isolated cartilage defects of the patella and a gender- and age-matched control group of patients without patellar cartilage defects. A total of 43 patients (17 female, 26 male) with arthroscopically verified grade III and IV patellar cartilage defects (defect group) were compared with a matched-pair control group of patients with isolated traumatic rupture of the anterior cruciate ligament without cartilage defects of the patellofemoral joint. Preoperative MRI images were analysed retrospectively with regard to patellar geometry (width, thickness, facet angle), trochlear geometry (dysplasia according to Dejour, sulcus angle, sulcus depth, lateral condyle index, trochlea facet asymmetry, lateral trochlea inclination) and patellofemoral alignment (tibial tuberosity-trochlear groove distance, patella height, lateral patella displacement, lateral patellofemoral angle, patella tilt, congruence angle). In addition to the comparison of group values, the measured values were compared to normal values reported in the literature, and the frequency of patients with pathologic findings was compared between both groups. The defect group demonstrated a significantly higher proximal chondral sulcus angle (p < 0.001), a significantly higher distal osseal sulcus angle (p = 0.004), a significantly lower distal sulcus depth (p = 0.047), a significantly lower lateral condyle index (p = 0.045), a significantly lower Caton-Deschamps index (p = 0.020) and a significantly higher Insall-Salvati index (p = 0.010). A major trochlear dysplasia (grade B-D) was significantly more common in the defect group (54 vs. 19%; p < 0.001). Eighty-eight per cent of patients in the defect group demonstrated at least one pathologic finding, compared to 63% in the control group (p = 0.006). Two or more pathologic findings were observed in 42% of the defect group and in 19% of the control group (p = 0.019). There was no significant correlation between the localization of the chondral defects and the results of the measured parameters. Cartilage defects of the patella are associated with the geometry of the patellofemoral joint. In particular, a flat and shallow trochlea, trochlea dysplasia and patella alta seem to contribute to the development of patellar cartilage defects, which must be taken into consideration when planning to do surgical cartilage repair at the patella. III.

Characterising the proximal patellar tendon attachment and its relationship to skeletal maturity in adolescent ballet dancers

PubMed Central

Rudavsky, Aliza; Cook, Jillianne; Magnusson, Stig Peter; Kjaer, Michael; Docking, Sean

2017-01-01

Summary Background It is unknown how and when the proximal attachment of the patellar tendon matures; puberty may be key in ensuring normal tendon formation. The aim of this study was to investigate the features of the proximal patellar tendon attachment at different stages of skeletal maturity, to help gain an understanding of how and when the tendon attachment matures. Methods Sixty adolescent elite ballet students (ages 11–18) and eight mature adults participated. Peak height velocity (PHV) estimated skeletal maturity. Ultrasound tissue characterisation (UTC) scan was taken of the left knee and analysed for stability of echopattern. An image-based grading scale for greyscale ultrasound was developed to describe the tendon appearance. Anterior-posterior thickness was measured at the inferior pole of the patella, 1 and 2 centimetres distally. Outcomes were compared with skeletal maturity. Results Mid-portion patellar tendon thickness increased with skeletal maturity (p=0.001 at 1 cm and p=0.007 at 2 cm). There was more variance in structural appearance (greyscale classification and UTC echopattern) in pre and peri-PHV participants. Tendon attachment one-year post PHV appeared similar to mature tendons. Conclusions Early adolescence was associated with highly variable tendon appearance, whereas the tendon appeared mature after PHV. Adolescence may be a critical time for the formation of normal tendon attachment. Level of evidence IIb individual cohort study. PMID:29264342

Landing limb posture in volleyball athletes with patellar tendinopathy: a pilot study.

PubMed

Kulig, K; Joiner, D G; Chang, Y-J

2015-05-01

The aims of this pilot study were to investigate how a novel sagittal plane kinematic measurement - the lower extremity contact angle (LECA) - relates to the landing dynamics of elite male volleyball athletes with and without patellar tendinopathy. The LECA was defined as the angle between the ground and the line connecting the center of pressure to the L5S1 marker. 18 athletes (9 with patellar tendinopathy and 9 with asymptomatic tendons) completed simulated spike jumps while instrumented for kinetic and kinematic analysis using a force platform and 3D motion analysis system. The patellar tendinopathic group demonstrated a significantly more acute LECA compared to the asymptomatic group (65.3°±2.2° vs. 69.1°±4.5°) and was the only kinematic or kinetic variable measured to discriminate between the 2 groups. The LECA further demonstrated less variability between trials than sagittal plane hip, knee, and ankle kinematics. Additionally, the LECA's - and not individual joints' - high correlation with the braking impulse ensures its predictive value for landing dynamics (r=- 0.890). The LECA has the potential to be a valuable tool to help assess jumping athletes in both injury prevention screening and as a variable that, if modified, could help alter the maladaptive behavior observed in symptomatic athletes. © Georg Thieme Verlag KG Stuttgart · New York.

Circumferential electrocautery of the patella in primary total knee replacement without patellar replacement: a meta-analysis and systematic review

PubMed Central

Fan, Lihong; Ge, Zhaogang; Zhang, Chen; Li, Jia; Yu, Zefeng; Dang, Xiaoqian; Wang, Kunzheng

2015-01-01

The purpose of this meta-analysis and systematic review was to identify and assess whether circumferential electrocautery is useful for improving outcomes after primary total knee replacement(TKR). We searched MEDLINE, EMBASE, PubMed, SpringerLink, Web of Knowledge, OVID CINAHL, OVID EBM and Google Scholar and included articles published through January 2014. A total of 6 articles met the inclusion criteria. Of the 776 cases included in the analysis, 388 cases involved patellar denervation, and 388 cases were designated as the control group. The meta-analysis revealed no significant difference in the incidence of anterior knee pain (AKP, p = 0.18) or in the visual analogue scale score (VAS, p = 0.23) between the two groups. In addition, AKSS Function Score indicated no significant difference between the two groups (p = 0.28). However, the OKS (p = 0.02), patellar score (p = 0.01), AKSS-Knee Score (p = 0.004), range of motion (ROM, p < 0.0001) and WOMAC Score (p = 0.0003) indicated that circumpatellarelectrocautery improved clinical outcomes compared with non-electrocautery. The results indicate that circumferential electrocautery of the patella does not significantly improve AKP compared with non-electrocautery techniques but that circumferential electrocautery significantly improves patients' knee function after surgery. Therefore, we believe that circumferential electrocautery is beneficial to the outcome of primary TKR surgery without patellar replacement. PMID:25801456

Circumferential electrocautery of the patella in primary total knee replacement without patellar replacement: a meta-analysis and systematic review.

PubMed

Fan, Lihong; Ge, Zhaogang; Zhang, Chen; Li, Jia; Yu, Zefeng; Dang, Xiaoqian; Wang, Kunzheng

2015-03-24

The purpose of this meta-analysis and systematic review was to identify and assess whether circumferential electrocautery is useful for improving outcomes after primary total knee replacement(TKR). We searched MEDLINE, EMBASE, PubMed, SpringerLink, Web of Knowledge, OVID CINAHL, OVID EBM and Google Scholar and included articles published through January 2014. A total of 6 articles met the inclusion criteria. Of the 776 cases included in the analysis, 388 cases involved patellar denervation, and 388 cases were designated as the control group. The meta-analysis revealed no significant difference in the incidence of anterior knee pain (AKP, p = 0.18) or in the visual analogue scale score (VAS, p = 0.23) between the two groups. In addition, AKSS Function Score indicated no significant difference between the two groups (p = 0.28). However, the OKS (p = 0.02), patellar score (p = 0.01), AKSS-Knee Score (p = 0.004), range of motion (ROM, p < 0.0001) and WOMAC Score (p = 0.0003) indicated that circumpatellarelectrocautery improved clinical outcomes compared with non-electrocautery. The results indicate that circumferential electrocautery of the patella does not significantly improve AKP compared with non-electrocautery techniques but that circumferential electrocautery significantly improves patients' knee function after surgery. Therefore, we believe that circumferential electrocautery is beneficial to the outcome of primary TKR surgery without patellar replacement.

Major complications of tibial tuberosity advancement in 1613 dogs.

PubMed

Costa, Mario; Craig, Diane; Cambridge, Tony; Sebestyen, Peter; Su, Yuhua; Fahie, Maria A

2017-05-01

To report major postoperative complications in 1613 dogs with tibial tuberosity advancement (TTA). Retrospective case series. Dogs (n = 1613) with cranial cruciate ligament deficiency treated with TTA. Medical records of TTAs performed between December 2007-2013 were reviewed for age, sex, weight, contralateral stifle surgery, surgical approach, duration of preoperative lameness, presence of meniscal damage, concurrent patellar luxation and simultaneous bilateral TTA. Major postoperative complications were defined as surgical site infection (SSI) (superficial, deep, or organ/space), implant failure, fracture, patellar luxation, and meniscal tear. Major complications were recorded in 13.4% of cases. Superficial SSI (incisional irritation) was diagnosed in 6.9% cases, requiring only antimicrobial therapy. Other complications included postliminary medial meniscal tear (2% incidence), deep SSI (incisional dehiscence, 1.1%), implant failure (1%), patellar luxation (1.2%), fracture (0.9%), and organ/space SSI (septic arthritis, 0.4%). Dogs with normal menisci were less likely to develop postliminary meniscal tears if the medial meniscus was released at the time of TTA (P < .0001). No association was detected between recorded parameters and complications, although dogs >8 years old approached significance (P = .05) in terms of predisposition to major complications. Major complications after TTA are uncommon, even in dogs with concurrent patellar luxation or bilateral simultaneous procedures. In spite of its morbidity, medial meniscal release may prevent postliminary meniscal tears. © 2017 The American College of Veterinary Surgeons.

Circumferential electrocautery of the patella in primary total knee replacement without patellar replacement: a meta-analysis and systematic review

NASA Astrophysics Data System (ADS)

Fan, Lihong; Ge, Zhaogang; Zhang, Chen; Li, Jia; Yu, Zefeng; Dang, Xiaoqian; Wang, Kunzheng

2015-03-01

The purpose of this meta-analysis and systematic review was to identify and assess whether circumferential electrocautery is useful for improving outcomes after primary total knee replacement(TKR). We searched MEDLINE, EMBASE, PubMed, SpringerLink, Web of Knowledge, OVID CINAHL, OVID EBM and Google Scholar and included articles published through January 2014. A total of 6 articles met the inclusion criteria. Of the 776 cases included in the analysis, 388 cases involved patellar denervation, and 388 cases were designated as the control group. The meta-analysis revealed no significant difference in the incidence of anterior knee pain (AKP, p = 0.18) or in the visual analogue scale score (VAS, p = 0.23) between the two groups. In addition, AKSS Function Score indicated no significant difference between the two groups (p = 0.28). However, the OKS (p = 0.02), patellar score (p = 0.01), AKSS-Knee Score (p = 0.004), range of motion (ROM, p < 0.0001) and WOMAC Score (p = 0.0003) indicated that circumpatellarelectrocautery improved clinical outcomes compared with non-electrocautery. The results indicate that circumferential electrocautery of the patella does not significantly improve AKP compared with non-electrocautery techniques but that circumferential electrocautery significantly improves patients' knee function after surgery. Therefore, we believe that circumferential electrocautery is beneficial to the outcome of primary TKR surgery without patellar replacement.

Flexing and downsizing the femoral component is not detrimental to patellofemoral biomechanics in posterior-referencing cruciate-retaining total knee arthroplasty.

PubMed

Marra, Marco A; Strzelczak, Marta; Heesterbeek, Petra J C; van de Groes, Sebastiaan A W; Janssen, Dennis; Koopman, Bart F J M; Verdonschot, Nico; Wymenga, Ate B

2018-03-20

When downsizing the femoral component to prevent mediolateral overhang, notching of the anterior femoral cortex may occur, which could be solved by flexing the femoral component. In this study, we investigated the effect of flexion of the femoral component on patellar tendon moment arm, patellofemoral forces and kinematics in posterior-referencing CR-TKA. Our hypothesis was that flexion of the femoral component increases the patellar tendon moment arm, reduces the patellofemoral forces and provides stable kinematics. A validated musculoskeletal model of CR-TKA was used. The flexion of the femoral component was increased in four steps (0°, 3°, 6°, 9°) using posterior referencing, and different alignments were analysed in combination with three implant sizes (3, 4, 5). A chair-rising trial was analysed using the model, while simultaneously estimating quadriceps muscle force, patellofemoral contact force, tibiofemoral and patellofemoral kinematics. Compared to the reference case (size 4 and 0° flexion), for every 3° of increase in flexion of the femoral component the patellar tendon moment arm increased by 1% at knee extension. The peak quadriceps muscle force and patellofemoral contact force decreased by 2%, the patella shifted 0.8 mm more anteriorly and the remaining kinematics remained stable, with knee flexion. With the smaller size, the patellar tendon moment arm decreased by 6%, the quadriceps muscle force and patellofemoral contact force increased by 8 and 12%, and the patellar shifted 5 mm more posteriorly. Opposite trends were found with the bigger size. Flexing the femoral component with posterior referencing reduced the patellofemoral contact forces during a simulated chair-rising trial with a patient-specific musculoskeletal model of CR-TKA. There seems to be little risk when flexing and downsizing the femoral component, compared to when using a bigger size and neutral alignment. These findings provide relevant information to surgeons who wish to prevent anterior notching when downsizing the femoral component.

The degeneration and destruction of femoral articular cartilage shows a greater degree of deterioration than that of the tibial and patellar articular cartilage in early stage knee osteoarthritis: a cross-sectional study.

PubMed

Hada, S; Kaneko, H; Sadatsuki, R; Liu, L; Futami, I; Kinoshita, M; Yusup, A; Saita, Y; Takazawa, Y; Ikeda, H; Kaneko, K; Ishijima, M

2014-10-01

The aim of the present study was to examine whether the degenerative and morphological changes of articular cartilage in early stage knee osteoarthritis (OA) occurred equally for both femoral- and tibial- or patellar- articular cartilage using magnetic resonance imaging (MRI)-based analyses. This cross-sectional study was approved by the ethics committee of our university. Fifty patients with early stage painful knee OA were enrolled. The patients underwent 3.0 T MRI on the affected knee joint. Healthy volunteers who did not show MRI-based OA changes were also recruited as controls (n = 19). The degenerative changes of the articular cartilage were quantified by a T2 mapping analysis, and any structural changes were conducted using Whole Organ Magnetic Resonance Imaging Score (WORMS) technique. All patients showed MRI-detected OA morphological changes. The T2 values of femoral condyle (FC) (P < 0.0001) and groove (P = 0.0001) in patients with early stage knee OA were significantly increased in comparison to those in the control, while no significant differences in the T2 values of patellar and tibial plateau (TP) were observed between the patients and the control. The WORMS cartilage and osteophyte scores of the femoral articular cartilage were significantly higher than those in the patellar- (P = 0.001 and P = 0.007, respectively) and tibial- (P = 0.0001 and P < 0.0001, respectively) articular cartilage in the patients with early stage knee OA. The degradation and destruction of the femoral articular cartilage demonstrated a greater degree of deterioration than those of the tibial- and patellar- articular cartilage in patients with early stage knee OA. Copyright © 2014 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Cross-cultural adaptation and validation of the VISA-P questionnaire for German-speaking patients with patellar tendinopathy.

PubMed

Lohrer, Heinz; Nauck, Tanja

2011-03-01

Clinical measurement study. To cross-culturally adapt and validate the Victorian Institute of Sports Assessment Patellar Tendinopathy Questionnaire (VISA-P) for German-speaking patients. Like most questionnaires, the VISA-P was developed for English-speaking patients. There is a need to adapt the scale for German-speaking patients and thereby add to the total body of psychometric evidence relating to this instrument. The VISA-P questionnaire was translated and cross-culturally adapted into German (VISA-P-G) in 6 steps: translation, synthesis, back translation, expert committee review, pretesting, and advisory committee appraisal. The psychometric properties of the VISA-P-G were determined using 23 patients with patellar tendinopathy and 57 active healthy persons (32 sport students and 25 basketball players). Reliability was evaluated by applying the questionnaire twice within a week to all 80 participants. Known group validity was calculated using a 1-way analysis of variance. Additionally, VISA-P-G results were correlated with the Blazina classification system for patellar tendinopathy, using the Spearman rank correlation coefficient. VISA-P-G ratings from the present study groups were further compared with respective data published in the original English, Dutch, and Swedish versions by a 2-sample t test. Internal consistency for the individual items of the questionnaire was determined within the patient group using a Cronbach alpha. Test-retest revealed excellent reliability for the patient and the asymptomatic control group (ICC = 0.88 and 0.87, respectively). Internal consistency for the patients was 0.88. Concurrent validity was almost perfect (ρ = -0.81; P<.001). The VISA-P-G is a reliable and valid questionnaire for the self-assessment of pain, symptoms, and function in German-speaking patients with patellar tendinopathy. Its psychometric properties are comparable with the original English and international adaptations (Swedish, Dutch, and Italian).

The Accuracy of the VISA-P Questionnaire, Single-Leg Decline Squat, and Tendon Pain History to Identify Patellar Tendon Abnormalities in Adult Athletes.

PubMed

Mendonça, Luciana de Michelis; Ocarino, Juliana Melo; Bittencourt, Natália Franco Netto; Fernandes, Ludmila Maria Oliveira; Verhagen, Evert; Fonseca, Sérgio Teixeira

2016-08-01

Study Design Cross-sectional clinical assessment. Background Patellar tendinopathy is not always accompanied by patellar tendon abnormalities (PTAs). Thus, clinical screening tools to help identify patients with patellar tendon pain who have PTAs could enhance clinical decision making and patient prognosis. Objectives To test the diagnostic accuracy of the Victorian Institute of Sport Assessment-Patella (VISA-P) questionnaire, a single-leg decline squat (SLDS), tendon pain history, age, and years of sports participation to identify athletes with symptomatic patellar tendons who have PTAs confirmed on imaging. Methods Data provided by ultrasound examination, the VISA-P questionnaire, the SLDS, tendon pain history, age, and years of sport participation were collected in 43 athletes. A classification and regression tree (CART) model was developed to verify variables associated with PTA occurrence. Likelihood ratios (LRs) were computed for positive and negative tests. Results The SLDS, VISA-P questionnaire, and tendon pain history were associated with PTA occurrence. Athletes with negative results on all 3 tests (CART model) had a lower likelihood of having PTAs (negative LR = 0.3; 95% confidence interval [CI]: 0.2, 0.5). The isolated use of the SLDS or tendon pain history (positive LR = 4.2; 95% CI: 2.3, 7.14 and 4.5; 95% CI: 1.8, 11.1, respectively) had similar influence on probability of PTA presence compared to the CART model (positive LR = 4.1; 95% CI: 2.5, 6.3). Conclusion Although the objective was to investigate a clinical test to identify PTAs, the combined use of the tests had greater accuracy to identify individuals without PTAs. Level of Evidence Diagnosis, level 3b. J Orthop Sports Phys Ther 2016;46(8):673-680. Epub 3 Jul 2016. doi:10.2519/jospt.2016.6192.

Knee injuries related to sports in young adult males during military service - incidence and risk factors.

PubMed

Kuikka, P-I; Pihlajamäki, H K; Mattila, V M

2013-06-01

The population-based incidence and risk factors for knee injuries in young adults were assessed in Finnish male conscripts performing their compulsory military service (n = 128,584). The main outcome variables were (1) hospitalization due to knee injuries overall and (2) hospitalization due to knee disorders as categorized into specific International Classification of Diseases, tenth revision diagnoses (cruciate and collateral ligament tears, meniscal tears, traumatic chondral lesions, and patellar dislocations). Person-time injury-incidence rates were calculated by dividing the number of persons with a diagnosed knee injury by the total exposure time of 97,503 person-years. The number of subjects with surgical operations and military service class changes indicative of longer term notable disability are also reported. Risk factor analyses were performed by logistic regression. The person-based incidence of hospitalizations for knee injury was 11 cases per 1000 person-years [95% confidence interval (CI): 10.4-11.7]. The most important risk factors were higher age (odds ratio 1.7; 95% CI: 1.3-2.2) and obesity (odds ratio 1.6; 95% CI: 1.03-2.5). Two thirds of all subjects hospitalized for knee injuries had surgery, and one third had longer term notable disability. These findings indicate that knee injuries cause a significant burden of hospitalizations, often leading to surgery and longer term disability. © 2011 John Wiley & Sons A/S.

[SPECIFIC DIAGNOSTIC SIGNIFICANCE OF "RIPPLE SIGN" OF MEDIAL FEMORAL CONDYLE UNDER ARTHROSCOPE IN MEDIAL LONGITUDINAL MENISCAL TEARS].

PubMed

Ren Shiyou; Sun, Limang; Chen, Guofei; Jiang, Changqing; Zhang, Xintao; Zhang Wentao

2015-01-01

To investigate the reliability of the "ripple sign" on the upper surface of the medial femoral condyle in the diagnosis of medial longitudinal meniscal tears under arthroscope. Between June 2013 and June 2014, 56 patients with knee injuries were included. There were 35 males and 21 females with an average age of 22.2 years (range, 12-38 years). The causes of injury were sports in 40 cases, falling in 10 cases, and traffic accident in 6 cases. The injury was located at the left knee in 22 cases and at the right knee in 34 cases. The disease duration was 10-40 days (mean, 20.2 days). Of 56 patients, 15 cases had simple medial meniscal injury; 41 cases had combined injuries, including anterior cruciate ligament injury in 38 cases, posterior cruciate ligament injury in 2 cases, and patellar dislocation in 1 case. The "ripple sign" was observed under arthroscope before operation. Repair of medial meniscal injury and reconstruction of cruciate ligament were performed. The positive "ripple sign" was seen under arthroscope in all patients, who were diagnosed to have longitudinal meniscal tears, including 23 cases of mild "ripple sign" , 28 cases of moderate "ripple sign", and 5 cases of severe "ripple sign". The "ripple sign" on the upper surface of the medial femoral condyle is a reliable diagnostic evidence of medial longitudinal meniscal tears.

What Is the Role for Patelloplasty With Gullwing Osteotomy in Revision TKA?

PubMed

Gililland, Jeremy M; Swann, Presley; Pelt, Christopher E; Erickson, Jill; Hamad, Nadia; Peters, Christopher L

2016-01-01

Management of the patella in revision total knee arthroplasty (TKA) is challenging as a result of the deficient or unusable bone stock for patellar resurfacing that is frequently encountered. Options proposed in this setting include various patelloplasty procedures, patellectomy, and special patellar components. We sought to better define the role and results of one patelloplasty procedure, the gullwing osteotomy, used in revision TKA. (1) How much improvement in the outcome measures of range of motion and Knee Society scores was seen after revision TKA with a gullwing osteotomy? (2) What are the radiographic results of this osteotomy as judged by patellar healing and patellar tracking? (3) What complications are associated with the gullwing osteotomy in revision TKA? Between December 2003 and July 2012, we used a gullwing osteotomy on patients undergoing revision TKA (n = 238) in which the patellar remnant was avascular or less than 12 mm thick. This uncommon procedure was used in 17 of 115 (15%) of the patellae revised during this time. We performed manual chart reviews on all patients to collect preoperative and postoperative range of motion and Knee Society scores as well as radiographic review at last followup to assess patellar healing and tracking. In patients with at least 2 years of followup, the preoperative range of motion was a median -7.5° of extension (interquartile range [IQR], -15°-0°) and 90° of flexion (IQR, 90°-100°). Postoperative extension improved to 0° (IQR, 0°-0°; p = 0.015). With the numbers available, median flexion arc did not change at last followup (110°; IQR, 95°-120°; p = 0.674). The Knee Society score improved from a combined (clinical + functional) mean of 86 (95% confidence interval [CI], 56-116) preoperatively to 142 (95% CI, 121-163; p < 0.001) postoperatively. Radiographically, 12 of 13 patients demonstrated healing of the osteotomy with osseous union and one patient healed with a fibrous union. Nine of the 10 patients with at least 2 years of followup had a centrally tracking gullwing osteotomized patella at last followup. One patient, with just over 3 years of followup, exhibited lateral subluxation without evidence of fracture. Three of the 10 patients with greater than 2 years of followup developed recurrent infections. One patient had avascular necrosis with fragmentation of the patella at 4 months postoperatively. Patellar bone stock is often compromised in revision TKA, leaving the surgeon with very few options for reconstruction. Using this technique, we found acceptable function, no aseptic rerevisions for patellofemoral complications, nine of 10 of patellae tracking within the trochlear groove, and radiographic healing of the majority of the osteotomies. The gullwing osteotomy may be considered an option in these difficult revisions, but further studies with more complete followup are needed. Level IV, therapeutic study.

High volume image-guided Injections for patellar tendinopathy: a combined retrospective and prospective case series.

PubMed

Morton, Sarah; Chan, Otto; King, John; Perry, David; Crisp, Tom; Maffulli, Nicola; Morrissey, Dylan

2014-04-01

the aim was to quantify the effect of a novel high volume-image guided injection (HVIGI) technique for recalcitrant patellar tendinopathy (PT). twenty patients (8 prospective; 12 retrospective) with ultrasonographically confirmed proximal PT were recruited. A HVIGI under ultra-sound guidance of 10 ml 0.5% Bupivacaine, 25 mg Hydrocortisone and 30 ml normal saline at the interface of the patellar tendon and Hoffa's fat pad was administered. A standardised eccentric loading rehabilitation protocol was prescribed. the VISA-P score improved from 45.0 to 64.0 (p<0.01) for all subjects, likely to be clinically significant. There was no statistically significant difference between the increase in the retrospective group of 19.9 (± 23.5) and the prospective of 16.4 (± 11.3) p = 0.7262.5% of prospective subjects agreed that they had significantly improved, with 37.5% returning to sport within 12 weeks. HVIGI should be considered in the management of recalcitrant PT. Randomised controlled trials are warranted.

Effectiveness of the Intratissue Percutaneous Electrolysis (EPI®) technique and isoinertial eccentric exercise in the treatment of patellar tendinopathy at two years follow-up.

PubMed

Abat, Ferran; Diesel, Wayne-J; Gelber, Pablo-E; Polidori, Fernando; Monllau, Joan-Carles; Sanchez-Ibañez, Jose-Manuel

2014-04-01

to show the effect of Intratissue Percutaneous Electrolysis (EPI®) combined with eccentric programme in the treatment of patellar tendinopathy. prospective study of 33 athlete-patients consecutively treated for insertional tendinopathy with Intratissue Percutaneous Electrolysis (EPI®) and followed for 2 years. Functional assessment was performed at the first visit, at three months and two years with the Tegner scale and VISA-P. an average improvement in the VISA-P of 35 points was obtained. The mean duration of treatment was 4.5 weeks. Some 78.8% of the patients returned to the same level of physical activity as before the injury by the end of treatment, reaching 100% at two years. intratissue percutaneous electrolysis (EPI®) combined with an eccentric-based rehab program offers excellent results in terms of the clinical and functional improvement of the patellar tendon with low morbidity in a short-term period. Therapy, level 4.

Implementation of an iPhone wireless accelerometer application for the quantification of reflex response.

PubMed

LeMoyne, Robert; Mastroianni, Timothy; Grundfest, Warren; Nishikawa, Kiisa

2013-01-01

The patellar tendon reflex represents an inherent aspect of the standard neurological evaluation. The features of the reflex response provide initial perspective regarding the status of the nervous system. An iPhone wireless accelerometer application integrated with a potential energy impact pendulum attached to a reflex hammer has been successfully developed, tested, and evaluated for quantifying the patellar tendon reflex. The iPhone functions as a wireless accelerometer platform. The wide coverage range of the iPhone enables the quantification of reflex response samples in rural and remote settings. The iPhone has the capacity to transmit the reflex response acceleration waveform by wireless transmission through email. Automated post-processing of the acceleration waveform provides feature extraction of the maximum acceleration of the reflex response ascertained after evoking the patellar tendon reflex. The iPhone wireless accelerometer application demonstrated the utility of the smartphone as a biomedical device, while providing accurate and consistent quantification of the reflex response.

Evaluation of patients presenting with knee pain: Part II. Differential diagnosis.

PubMed

Calmbach, Walter L; Hutchens, Mark

2003-09-01

Knee pain is a common presenting complaint with many possible causes. An awareness of certain patterns can help the family physician identify the underlying cause more efficiently. Teenage girls and young women are more likely to have patellar tracking problems such as patellar subluxation and patellofemoral pain syndrome, whereas teenage boys and young men are more likely to have knee extensor mechanism problems such as tibial apophysitis (Osgood-Schlatter lesion) and patellar tendonitis. Referred pain resulting from hip joint pathology, such as slipped capital femoral epiphysis, also may cause knee pain. Active patients are more likely to have acute ligamentous sprains and overuse injuries such as pes anserine bursitis and medial plica syndrome. Trauma may result in acute ligamentous rupture or fracture, leading to acute knee joint swelling and hemarthrosis. Septic arthritis may develop in patients of any age, but crystal-induced inflammatory arthropathy is more likely in adults. Osteoarthritis of the knee joint is common in older adults.

Does Patellar Eversion in Total Knee Arthroplasty Cause Patella Baja?

PubMed Central

Sharma, Vineet; Tsailas, Panagiotis G.; Maheshwari, Aditya V.; Ranawat, Chitranjan S.

2008-01-01

Several proponents of minimally invasive surgery-total knee arthroplasty (MIS-TKA) have suggested patellar eversion during a standard exposure of the knee may cause shortening of the patellar tendon and poorer outcomes secondary to acquired patella baja. To explore this suggestion, we retrospectively reviewed 135 consecutive TKAs in 110 patients to ascertain the effect of TKA on the postoperative Insall-Salvati ratio. All surgeries were performed using standard TKA techniques with a midline incision, medial parapatellar arthrotomy, partial excision of the fat pad, and routine eversion of the patella. One patient developed a postoperative patella baja, defined as an Insall-Salvati ratio of less than 0.8. The Knee Society score for knee and function in this patient was 75 and 70, respectively. Five additional patients had a decrease in Insall-Salvati ratio by 10% or more but without patella baja. Mean Knee Society score for knee and function in these five patients was 94 (range, 73–99) and 96 (range, 90–100), respectively, as compared with 93 (range, 37–99) and 94 (range, 40–100) in the remaining 104 patients. Our data suggest the incidence of patella baja is low after TKA despite routine patellar eversion. Furthermore, a 10% or more decrease in the Insall-Salvati ratio without patella baja was not associated with a worse clinical outcome. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18568378

Non-resurfacing techniques in the management of the patella at total knee arthroplasty: A systematic review and meta-analysis.

PubMed

Findlay, I; Wong, F; Smith, C; Back, D; Davies, A; Ajuied, A

2016-03-01

Recent meta-analyses support not resurfacing the patella at the time of TKA. Several different modes of intervention are reported for non-resurfacing management of the patella at TKA. We have conducted a systematic review and meta-analysis of non-resurfacing interventions in TKA. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) study methodology and reporting system was adopted, utilising the PRISMA checklist and statement. Classes of patella interventions were defined as: 0. No intervention. 1. Osteophyte excision only. 2. Osteophyte excision, denervation, with soft tissue debridement. 3. Osteophyte excision, denervation, soft tissue debridement, and drilling or micro-fracture of eburnated bone. 4. Patellar resurfacing. A meta-analysis was conducted upon the pre- and post-operative KSS for each technique. Four hundred and twenty-three studies were identified, 12 studies met the inclusion criteria for the systematic review and eight for the meta-analysis. Two studies compared different non-resurfacing patellar techniques, the other studies used the non-resurfacing cohort as controls for their prospective RCTs comparing patellar resurfacing with non-resurfacing. The meta-analysis revealed no significant difference between the techniques. We conclude that there is no significant difference in KSS for differing non-resurfacing patellar techniques, but further trials using patellofemoral specific scores may better demonstrate superior efficacy of specific classes of patella intervention, by virtue of greater sensitivity for patellofemoral pain and dysfunction. I. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Mcconnell's patellar taping does not alter knee and hip muscle activation differences during proprioceptive exercises: A randomized placebo-controlled trial in women with patellofemoral pain syndrome.

PubMed

Araújo, Cynthia Gobbi Alves; de Souza Guerino Macedo, Christiane; Ferreira, Daiene; Shigaki, Leonardo; da Silva, Rubens A

2016-12-01

The purpose of this study was to assess the effect of patellar taping on muscle activation of the knee and hip muscles in women with Patellofemoral Pain Syndrome during five proprioceptive exercises. Forty sedentary women with syndrome were randomly allocated in two groups: Patellar Taping (based in McConnell) and Placebo (vertical taping on patella without any stretching of lateral structures of the knee). Volunteers performed five proprioceptive exercises randomly: Swing apparatus, Mini-trampoline, Bosu balance ball, Anteroposterior sway on a rectangular board and Mediolateral sway on a rectangular board. All exercises were performed in one-leg stance position with injured knee at flexion of 30° during 15s. Muscle activation was measured by surface electromyography across Vastus Medialis, Vastus Lateralis and Gluteus medius muscles. Maximal voluntary contraction was performed for both hip and knee muscles in order to normalize electromyography signal relative to maximum effort during the exercises. ANOVA results reported no significant interaction (P>0.05) and no significant differences (P>0.05) between groups and intervention effects in all exercise conditions. Significant differences (P<0.01) were only reported between muscles, where hip presented higher activity than knee muscles. Patellar taping is not better than placebo for changes in the muscular activity of both hip and knee muscles during proprioceptive exercises. ClinicalTrials.gov NCT02322515. Copyright © 2016 Elsevier Ltd. All rights reserved.

Increased serum cartilage oligomeric matrix protein levels and decreased patellar bone mineral density in patients with chondromalacia patellae

PubMed Central

Murphy, E; FitzGerald, O; Saxne, T; Bresnihan, B

2002-01-01

Background: Chondromalacia patellae is a potentially disabling disorder characterised by features of patellar cartilage degradation. Objective: To evaluate markers of cartilage and bone turnover in patients with chondromalacia patellae. Methods: 18 patients with chondromalacia patellae were studied. Serum cartilage oligomeric matrix protein (s-COMP) and bone sialoprotein (s-BSP) levels were measured by enzyme linked immunosorbent assay (ELISA) and compared with those of age and sex matched healthy control subjects. Periarticular bone mineral density (BMD) of both knee joints was assessed by dual energy x ray absorptiometry (DXA). Results: s-COMP levels were significantly raised in all patients with chondromalacia patellae compared with healthy control subjects (p=0.0001). s-BSP levels did not differ significantly between the groups (p=0.41). BMD of the patella was significantly reduced in patients with chondromalacia patellae compared with the control subjects (p=0.016). In patients with bilateral chondromalacia patellae, BMD of the patella was lower in the more symptomatic knee joint (p=0.005). Changes in periarticular BMD were localised to the patella and were not present in femoral regions. Neither s-COMP (p=0.18) nor s-BSP (p=0.40) levels correlated with patellar BMD. Conclusions: Increased s-COMP levels, reflecting cartilage degradation, and reduced BMD localised to the patella may represent clinically useful markers in the diagnosis and monitoring of patients with chondromalacia patellae. Measures of cartilage degradation did not correlate with loss of patellar bone density, suggesting dissociated pathophysiological mechanisms. PMID:12379520

Increased serum cartilage oligomeric matrix protein levels and decreased patellar bone mineral density in patients with chondromalacia patellae.

PubMed

Murphy, E; FitzGerald, O; Saxne, T; Bresnihan, B

2002-11-01

Chondromalacia patellae is a potentially disabling disorder characterised by features of patellar cartilage degradation. To evaluate markers of cartilage and bone turnover in patients with chondromalacia patellae. 18 patients with chondromalacia patellae were studied. Serum cartilage oligomeric matrix protein (s-COMP) and bone sialoprotein (s-BSP) levels were measured by enzyme linked immunosorbent assay (ELISA) and compared with those of age and sex matched healthy control subjects. Periarticular bone mineral density (BMD) of both knee joints was assessed by dual energy x ray absorptiometry (DXA). s-COMP levels were significantly raised in all patients with chondromalacia patellae compared with healthy control subjects (p=0.0001). s-BSP levels did not differ significantly between the groups (p=0.41). BMD of the patella was significantly reduced in patients with chondromalacia patellae compared with the control subjects (p=0.016). In patients with bilateral chondromalacia patellae, BMD of the patella was lower in the more symptomatic knee joint (p=0.005). Changes in periarticular BMD were localised to the patella and were not present in femoral regions. Neither s-COMP (p=0.18) nor s-BSP (p=0.40) levels correlated with patellar BMD. Increased s-COMP levels, reflecting cartilage degradation, and reduced BMD localised to the patella may represent clinically useful markers in the diagnosis and monitoring of patients with chondromalacia patellae. Measures of cartilage degradation did not correlate with loss of patellar bone density, suggesting dissociated pathophysiological mechanisms.

Description of patellar movement by 3D parameters obtained from dynamic CT acquisition

NASA Astrophysics Data System (ADS)

de Sá Rebelo, Marina; Moreno, Ramon Alfredo; Gobbi, Riccardo Gomes; Camanho, Gilberto Luis; de Ávila, Luiz Francisco Rodrigues; Demange, Marco Kawamura; Pecora, Jose Ricardo; Gutierrez, Marco Antonio

2014-03-01

The patellofemoral joint is critical in the biomechanics of the knee. The patellofemoral instability is one condition that generates pain, functional impairment and often requires surgery as part of orthopedic treatment. The analysis of the patellofemoral dynamics has been performed by several medical image modalities. The clinical parameters assessed are mainly based on 2D measurements, such as the patellar tilt angle and the lateral shift among others. Besides, the acquisition protocols are mostly performed with the leg laid static at fixed angles. The use of helical multi slice CT scanner can allow the capture and display of the joint's movement performed actively by the patient. However, the orthopedic applications of this scanner have not yet been standardized or widespread. In this work we present a method to evaluate the biomechanics of the patellofemoral joint during active contraction using multi slice CT images. This approach can greatly improve the analysis of patellar instability by displaying the physiology during muscle contraction. The movement was evaluated by computing its 3D displacements and rotations from different knee angles. The first processing step registered the images in both angles based on the femuŕs position. The transformation matrix of the patella from the images was then calculated, which provided the rotations and translations performed by the patella from its position in the first image to its position in the second image. Analysis of these parameters for all frames provided real 3D information about the patellar displacement.

Immediate effects of whole body vibration on patellar tendon properties and knee extension torque.

PubMed

Rieder, F; Wiesinger, H-P; Kösters, A; Müller, E; Seynnes, O R

2016-03-01

Reports about the immediate effects of whole body vibration (WBV) exposure upon torque production capacity are inconsistent. However, the changes in the torque-angle relationship observed by some authors after WBV may hinder the measurement of torque changes at a given angle. Acute changes in tendon mechanical properties do occur after certain types of exercise but this hypothesis has never been tested after a bout of WBV. The purpose of the present study was to investigate whether tendon compliance is altered immediately after WBV, effectively shifting the optimal angle of peak torque towards longer muscle length. Twenty-eight subjects were randomly assigned to either a WBV (n = 14) or a squatting control group (n = 14). Patellar tendon CSA, stiffness and Young's modulus and knee extension torque-angle relationship were measured using ultrasonography and dynamometry 1 day before and directly after the intervention. Tendon CSA was additionally measured 24 h after the intervention to check for possible delayed onset of swelling. The vibration intervention had no effects on patellar tendon CSA, stiffness and Young's modulus or the torque-angle relationship. Peak torque was produced at ~70° knee angle in both groups at pre- and post-test. Additionally, the knee extension torque globally remained unaffected with the exception of a small (-6%) reduction in isometric torque at a joint angle of 60°. The present results indicate that a single bout of vibration exposure does not substantially alter patellar tendon properties or the torque-angle relationship of knee extensors.

Sagittal plane tilting deformity of the patellofemoral joint: a new concept in patients with chondromalacia patella.

PubMed

Aksahin, Ertugrul; Aktekin, Cem Nuri; Kocadal, Onur; Duran, Semra; Gunay, Cüneyd; Kaya, Defne; Hapa, Onur; Pepe, Murad

2017-10-01

The aims of this study were to evaluate sagittal plane alignment in patients with chondromalacia patella via magnetic resonance imaging (MRI), analyse the relationships between the location of the patellar cartilaginous lesions and sagittal alignment and finally investigate the relationships between the sagittal plane malalignment and patellofemoral loadings using by finite element analysis. Fifty-one patients who were diagnosed with isolated modified Outerbridge grade 3-4 patellar chondromalacia based on MRI evaluation and 51 control subjects were evaluated. Chondromalacia patella patients were divided into three subgroups according to the chondral lesion location as superior, middle and inferior. The patella-patellar tendon angle (P-PT) was used for evaluation of sagittal alignment of patellofemoral joint. Each subgroup was compared with control group by using P-PT angle. To investigate the biomechanical effects of sagittal plane malpositioning on patellofemoral joint, bone models were created at 30°, 60° and 90° knee flexion by using mean P-PT angles, which obtained from patients with chondromalacia patellae and control subjects. The total loading and contact area values of the patellofemoral joints were investigated by finite element analysis. The mean age of all participants was 52.9 ± 8.2 years. The mean P-PT angle was significantly lower in chondromalacia group (142.1° ± 3.6°) compared to control group (144.5° ± 5.3°) (p = 0.008). Chondral lesions were located in superior, middle and inferior zones in 16, 20 and 15 patients, respectively. The mean P-PT angles in patients with superior (141.8 ± 2.7) and inferior subgroups (139.2 ± 2.3) were significantly lower than the values in the control group (p < 0.05). The contact area values were detected higher in models with chondromalacia than in the control models at the same flexion degrees. There were increased loadings at 30° and 90° flexions in the sagittal patellar tilt models. This study revealed that sagittal plain malpositioning of the patellofemoral joint might be related to chondromalacia, especially in the presence of lesions in the upper and lower part of the patella. This condition leads to supraphysiological loadings on the patellofemoral joint. Sagittal patellar tilt should be considered in the evaluation and management of patellar cartilage defects. Taking sagittal plane malalignment into consideration in patellofemoral joint evaluation will enable us to design new physical and surgical modalities. IV.

Changes of synovial fluid protein concentrations in supra-patellar bursitis patients after the injection of different molecular weights of hyaluronic acid.

PubMed

Chen, Carl P C; Hsu, Chih Chin; Pei, Yu-Cheng; Chen, Ruo Li; Zhou, Shaobo; Shen, Hsuan-Chen; Lin, Shih-Cherng; Tsai, Wen Chung

2014-04-01

Knee pain is commonly seen in orthopedic and rehabilitation outpatient clinical settings, and in the aging population. Bursitis of the knee joint, especially when the volume of the synovial fluid is large enough, can compress and distend the nearby soft tissues, causing pain in the knee joint. Out of all the bursae surrounding the knee joint, supra-patellar bursitis is most often associated with knee pain. Treatment strategies in managing supra-patellar bursitis include the aspiration of joint synovial fluid and then followed by steroid injection into the bursa. When supra-patellar bursitis is caused by degenerative disorders, the concept of viscosupplementation treatment may be effective by injecting hyaluronic acid into the bursa. However, the rheology or the changes in the concentrations of proteins (biomarkers) that are related to the development of bursitis in the synovial fluid is virtually unexplored. Therefore, this study aimed to identify the concentration changes in the synovial fluid total protein amount and individual proteins associated with supra-patellar bursitis using the Bradford protein assay and western immunoglobulin methods. A total of 20 patients were divided into two groups with 10 patients in each group. One group received the high molecular weight hyaluronic acid product of Synvisc Hylan G-F 20 and the other group received the low molecular weight hyaluronic acid product of Hya-Joint Synovial Fluid Supplement once per week injection into the bursa for a total of 3 weeks. Significant decreases in the synovial fluid total protein concentrations were observed after the second dosage of high molecular weight hyaluronic acid injections. Apolipoprotein A-I, interleukin 1 beta, alpha 1 antitrypsin, and matrix metalloproteinase 1 proteins revealed a trend of decreasing western immunoblotting band densities after hyaluronic acid injections. The decreases in apolipoprotein A-I and interleukin 1 beta protein band densities were significant in the high molecular weight hyaluronic acid injection group. Transthyretin, complement 5, and matrilin 3 proteins revealed a trend of increasing western immunoblotting band densities after hyaluronic acid injections. Transthyretin revealed significant increases in protein band densities in both the high and low molecular weight hyaluronic acid injection groups. This study may provide the rationale for targeting several biomarkers associated with lipid transport, inflammation, and anti-aging as possible disease modifying therapies for the treatment of supra-patellar bursitis and even degenerative joint disorders. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Effect of Intraoperative Platelet-Rich Plasma Treatment on Postoperative Donor Site Knee Pain in Patellar Tendon Autograft Anterior Cruciate Ligament Reconstruction: A Double-Blind Randomized Controlled Trial.

PubMed

Walters, Brian L; Porter, David A; Hobart, Sarah J; Bedford, Benjamin B; Hogan, Daniel E; McHugh, Malachy M; Klein, Devon A; Harousseau, Kendall; Nicholas, Stephen J

2018-05-01

Donor site morbidity in the form of anterior knee pain is a frequent complication after bone-patellar tendon-bone (BPTB) autograft anterior cruciate ligament (ACL) reconstruction. Hypothesis/Purpose: The purpose was to examine the effect of the intraoperative administration of platelet-rich plasma (PRP) on postoperative kneeling pain. It was hypothesized that PRP treatment would reduce knee pain. Randomized controlled trial; Level of evidence, 2. Fifty patients (mean ± SD age, 30 ± 12 years) undergoing BPTB ACL autograft reconstruction were randomized to the PRP (n = 27) or sham (n = 23) treatment. In either case, 10 mL of venous blood was drawn before the induction of anesthesia and either discarded (sham) or processed (PRP) for preparation of a PRP gel to be later mixed with donor site bone chips and inserted into the patellar defect. At 12 weeks, 6 months, 1 year, and 2 years after surgery, patients completed International Knee Documentation Committee (IKDC) forms and visual analog scale pain scores for activities of daily living and kneeling. Healing indices at the donor site were assessed by routine noncontrast magnetic resonance imaging (MRI) at 6 months. Mixed-model analysis of variance was used to assess the effect of PRP on patient symptoms and MRI indices of donor site healing, as measured by the width of the donor site defect. Kneeling pain, pain with activities of daily living, and IKDC scores were not different between treatment groups at any of the time intervals ( P = .08-.83). Kneeling pain improved from 12 weeks to 6 months and from 1 to 2 years ( P < .05). IKDC scores improved substantially from 12 weeks to 6 months ( P < .001) and continued to improve to 2 years (PRP, 86 ± 19; sham, 89 ± 10). MRI indices of donor site healing were not different between treatment groups ( P = .53-.90). Whether randomized to receive PRP in their patellar defect or not, patients continued to have similar levels of kneeling pain and patellar defect sizes after autograft BPTB ACL reconstruction. Registration: NCT01765712 ( ClinicalTrials.gov identifier).

The intra- and inter-observer reliability of the physical examination methods used to assess patients with patellofemoral joint instability.

PubMed

Smith, Toby O; Clark, Allan; Neda, Sophia; Arendt, Elizabeth A; Post, William R; Grelsamer, Ronald P; Dejour, David; Almqvist, Karl Fredrik; Donell, Simon T

2012-08-01

An accurate physical examination of patients with patellar instability is an important aspect of the diagnosis and treatment. While previous studies have assessed the diagnostic accuracy of such physical examination tests, little has been undertaken to assess the inter- and intra-tester reliability of such techniques. The purpose of this study was to determine the inter- and intra-tester reliability of the physical examination tests used for patients with patellar instability. Five patients (10 knees) with bilateral recurrent patellar instability were assessed by five members of the International Patellofemoral Study Group. Each surgeon assessed each patient twice using 18 reported physical examination tests. The inter- and intra-observer reliability was assessed using weighted Kappa statistics with 95% confidence intervals. The findings of the study suggested that there were very poor inter-observer reliability for the majority of the physical tests, with only the assessments of patellofemoral crepitus, foot arch position and the J-sign presenting with fair to moderate agreement respectively. The intra-observer reliability indicated largely moderate to substantial agreement between the first and second tests performed by each assessor, with the greatest agreement seen for the assessment of tibial torsion, popliteal angle and the Bassett's sign. For the common physical examination tests used in the management of patients with patellar instability inter-observer reliability is poor, while intra-observer reliability is moderate. Standardization of physical exam assessments and further study of these results among different clinicians and more divergent patient groups is indicated. Copyright © 2011 Elsevier B.V. All rights reserved.

Patellar maltracking is prevalent among patellofemoral pain subjects with patella alta: an upright, weightbearing MRI study

PubMed Central

Pal, Saikat; Besier, Thor F.; Beaupre, Gary S.; Fredericson, Michael; Delp, Scott L.; Gold, Garry E.

2012-01-01

The purpose of this study is to determine if patellar maltracking is more prevalent among patellofemoral (PF) pain subjects with patella alta compared to subjects with normal patella height. We imaged 37 PF pain and 15 pain free subjects in an open-configuration magnetic resonance imaging scanner while they stood in a weightbearing posture. We measured patella height using the Caton-Deschamps, Blackburne-Peel, Insall-Salvati, Modified Insall-Salvati, and Patellotrochlear indices, and classified the subjects into patella alta and normal patella height groups. We measured patella tilt and bisect offset from oblique-axial plane images, and classified the subjects into maltracking and normal tracking groups. Patellar maltracking was more prevalent among PF pain subjects with patella alta compared to PF pain subjects with normal patella height (two-tailed Fisher’s exact test, p < 0.050). Using the Caton-Deschamps index, 67% (8/12) of PF pain subjects with patella alta were maltrackers, whereas only 16% (4/25) of PF pain subjects with normal patella height were maltrackers. Patellofemoral pain subjects classified as maltrackers displayed a greater patella height compared to the pain free and PF pain subjects classified as normal trackers (two-tailed unpaired t-tests with Bonferroni correction, p < 0.017). This study adds to our understanding of PF pain in two ways - 1) we demonstrate that patellar maltracking is more prevalent in PF pain subjects with patella alta compared to subjects with normal patella height; and 2) we show greater patella height in PF pain subjects compared to pain free subjects using four indices commonly used in clinics. PMID:23165335

Evaluation of the isometry of different points of the patella and femur for medial patellofemoral ligament reconstruction.

PubMed

Gobbi, Riccardo Gomes; Pereira, César Augusto Martins; Sadigursky, David; Demange, Marco Kawamura; Tírico, Luis Eduardo Passarelli; Pécora, José Ricardo; Camanho, Gilberto Luis

2016-10-01

The location of patellar and femoral fixation of the graft in medial patellofemoral ligament reconstructions has been widely discussed. This study aimed to assess the distances between different patellar and femoral fixation points to identify the least anisometric pairs of points. Ten cadaver knees were attached to an apparatus that simulated an active range of motion of 120°, with three metallic markers fixed onto the medial side of the patella, and seven markings onto the medial epicondyle. The examined points included the proximal patella pole (1), the patellar center (3), the midpoint between points 1 and 3 (2), a point directly on the epicondyle (6), points 5mm anterior (5) and posterior (7) to the epicondyle, points 5mm anterior to point 5 (4) and 5mm posterior to point 7 (8), and points 5mm proximal (9) and distal (10) to the epicondyle. The distances between patella and femur points were measured by a photogrammetry system at 15° intervals. The pair of points that exhibited the lowest average variability in distance, and hence was the most isometric, was the patella center combined with the anterior to the medial femoral epicondyle. The pairs of points that exhibited the highest average variability in distance, and hence were the least isometric, were the ones located distal or posterior to the medial femoral epicondyle, with less influence by the patellar location. Surgeons should avoid positioning the graft distally or posterior to the epicondyle due to the increase in anisometry. Copyright © 2016 Elsevier Ltd. All rights reserved.

Non-metallic implant for patellar fracture fixation: A systematic review.

PubMed

Camarda, Lawrence; Morello, Salvatore; Balistreri, Francesco; D'Arienzo, Antonio; D'Arienzo, Michele

2016-08-01

Despite good clinical outcome proposals, there has been relatively little published regarding the use of non-metallic implant for patellar fracture fixation. The purpose of the study was to perform a systematic literature review to summarize and evaluate the clinical studies that described techniques for treating patella fractures using non-metallic implants. A comprehensive literature search was systematically performed to evaluate all studies included in the literature until November 2015. The following search terms were used: patellar fracture, patella suture, patella absorbable, patella screw, patella cerclage. Two investigators independently reviewed all abstracts and the selection of these abstracts was then performed based on inclusion and/or exclusion criteria. A total of 9 studies involving 123 patients were included. Patients had a mean age of 33.7 years and were followed up for a mean of 18.9 months. The most common method for fracture fixations included the use of suture material. Good clinical outcomes were reported among all studies. Thirteen patients (10.5%) presented complications, while 4 patients (3.2%) required additional surgery for implant removal. There is a paucity of literature focused on the use of non-metallic implant for patellar fracture fixation. However, this systematic review showed that non-metallic implants are able to deliver good clinical outcomes reducing the rate of surgical complications and re-operation. These results may assist surgeons in choosing to use alternative material such as sutures to incorporate into their routine practice or to consider it, in order to reduce the rate of re-operation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Medial Patellofemoral Ligament Reconstruction Using the Hamstring Tendon for Patellofemoral Joint Instability in an 81-Year-Old Female.

PubMed

Takahashi, Tsuneari; Takeshita, Katsushi

2017-01-01

Chronic patellofemoral instability occurs mainly in adolescent females and can also be induced by medial patellofemoral ligament (MPFL) injury. There are no case reports of MPFL reconstruction for chronic patellofemoral instability due to MPFL injury in aged populations. 81-year-old female presented with left knee pain, giving way, and patellar instability while climbing stairs, which continued for 18 months. Patellar apprehension test was positive, and roentgenogram showed lateral patellar subluxation. Conservative therapy was not successful; hence, we performed a lateral release and MPFL reconstruction surgery. After arthroscopic lateral release, the hamstring tendon was harvested, and a graft composite made of doubled hamstring tendon and polyester tape with a suspensory fixation device was prepared. Then, a femoral bone tunnel was constructed in a socket shape at the anatomical footprint of the MPFL. The graft was passed through the femoral tunnel, and free ends of the graft composite were sutured to the periosteum of the patella, using two suture anchors at 60° of knee flexion with patellar reduction. Physiotherapy was gradually started using a patella-stabilizing orthosis on the first postoperative day. Her Kujala score improved from 66 to 97 points, and Barthel index score improved from 70 to 100 points at 1 year after surgery. She neither developed patellofemoral joint OA nor had any recurrence of symptoms at the 5-year postoperative follow up. MPFL reconstruction using the hamstring tendon is an effective procedure for patients with chronic patellofemoral instability even after the age of 80 years.

A randomised, controlled trial of circumpatellar electrocautery in total knee replacement without patellar resurfacing: a concise follow-up at a mean of 3.7 years.

PubMed

van Jonbergen, H P W; Scholtes, V A B; Poolman, R W

2014-04-01

In the absence of patellar resurfacing, we have previously shown that the use of electrocautery around the margin of the patella improved the one-year clinical outcome of total knee replacement (TKR). In this prospective randomised study we compared the mean 3.7 year (1.1 to 4.2) clinical outcomes of 300 TKRs performed with and without electrocautery of the patellar rim: this is an update of a previous report. The overall prevalence of anterior knee pain was 32% (95% confidence intervals [CI] 26 to 39), and 26% (95% CI 18 to 35) in the intervention group compared with 38% (95% CI 29 to 48) in the control group (chi-squared test; p = 0.06). The overall prevalence of anterior knee pain remained unchanged between the one-year and 3.7 year follow-up (chi-squared test; p = 0.12). The mean total Western Ontario McMasters Universities Osteoarthritis Indices and the American Knee Society knee and function scores at 3.7 years' follow-up were similar in the intervention and control groups (repeated measures analysis of variance p = 0.43, p = 0.09 and p = 0.59, respectively). There were no complications. A total of ten patients (intervention group three, control group seven) required secondary patellar resurfacing after the first year. Our study suggests that the improved clinical outcome with electrocautery denervation compared with no electrocautery is not maintained at a mean of 3.7 years' follow-up.

Validation of predicted patellofemoral mechanics in a finite element model of the healthy and cruciate-deficient knee.

PubMed

Ali, Azhar A; Shalhoub, Sami S; Cyr, Adam J; Fitzpatrick, Clare K; Maletsky, Lorin P; Rullkoetter, Paul J; Shelburne, Kevin B

2016-01-25

Healthy patellofemoral (PF) joint mechanics are critical to optimal function of the knee joint. Patellar maltracking may lead to large joint reaction loads and high stresses on the articular cartilage, increasing the risk of cartilage wear and the onset of osteoarthritis. While the mechanical sources of PF joint dysfunction are not well understood, links have been established between PF tracking and abnormal kinematics of the tibiofemoral (TF) joint, specifically following cruciate ligament injury and repair. The objective of this study was to create a validated finite element (FE) representation of the PF joint in order to predict PF kinematics and quadriceps force across healthy and pathological specimens. Measurements from a series of dynamic in-vitro cadaveric experiments were used to develop finite element models of the knee for three specimens. Specimens were loaded under intact, ACL-resected and both ACL and PCL-resected conditions. Finite element models of each specimen were constructed and calibrated to the outputs of the intact knee condition, and subsequently used to predict PF kinematics, contact mechanics, quadriceps force, patellar tendon moment arm and patellar tendon angle of the cruciate resected conditions. Model results for the intact and cruciate resected trials successfully matched experimental kinematics (avg. RMSE 4.0°, 3.1mm) and peak quadriceps forces (avg. difference 5.6%). Cruciate resections demonstrated either increased patellar tendon loads or increased joint reaction forces. The current study advances the standard for evaluation of PF mechanics through direct validation of cruciate-resected conditions including specimen-specific representations of PF anatomy. Copyright © 2015 Elsevier Ltd. All rights reserved.

The relation between chondromalacia patella and meniscal tear and the sulcus angle/ trochlear depth ratio as a powerful predictor.

PubMed

Resorlu, Hatice; Zateri, Coskun; Nusran, Gurdal; Goksel, Ferdi; Aylanc, Nilufer

2017-01-01

To investigate the relation between chondromalacia patella and the sulcus angle/trochlear depth ratio as a marker of trochlear morphology. In addition, we also planned to show the relationship between meniscus damage, subcutaneous adipose tissue thickness as a marker of obesity, patellar tilt angle and chondromalacia patella. Patients with trauma, rheumatologic disease, a history of knee surgery and patellar variations such as patella alba and patella baja were excluded. Magnetic resonance images of the knees of 200 patients were evaluated. Trochlear morphology from standardized levels, patellar tilt angle, lateral/medial facet ratio, subcutaneous adipose tissue thickness from 3 locations and meniscus injury were assessed by two specialist radiologists. Retropatellar cartilage was normal in 108 patients (54%) at radiological evaluation, while chondromalacia patella was determined in 92 (46%) cases. Trochlear sulcus angle and prepatellar subcutaneous adipose tissue thickness were significantly high in patients with chondromalacia patella, while trochlear depth and lateral patellar tilt angle were low. The trochlear sulcus angle/trochlear depth ratio was also high in chondromalacia patella and was identified as an independent risk factor at regression analysis. Additionally, medial meniscal tear was observed in 35 patients (38%) in the chondromalacia patella group and in 27 patients (25%) in the normal group, the difference being statistically significant (P = 0.033). An increased trochlear sulcus angle/trochlear depth ratio is a significant predictor of chondromalacia patella. Medial meniscus injury is more prevalent in patients with chondromalacia patella in association with impairment in knee biomechanics and the degenerative process.

All-Arthroscopic Autologous Matrix-Induced Chondrogenesis-Aided Repair of a Patellar Cartilage Defect Using Dry Arthroscopy and a Retraction System.

PubMed

Sadlik, Boguslaw; Puszkarz, Mariusz; Kosmalska, Lidia; Wiewiorski, Martin

2017-11-01

The technique of all-arthroscopic autologous matrix-induced chondrogenesis (AMIC)-aided repair of patellar cartilage lesions using a retraction system and dry arthroscopy has been recently described. We report the first clinical and radiological data at a short-term follow-up. Twelve patients underwent AMIC-aided cartilage repair for a patellar lesion. All steps of the procedure were performed arthroscopically, which include the use of an intra-articularly placed retraction plate for distraction of the patellofemoral joint and evacuation of saline solution for collagen matrix insertion and fixation. Clinical assessment performed before surgery and at a mean follow-up time of 38 months (range: 24-70) included the following scores: Knee Injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC), and visual analog scale (VAS). Magnetic resonance imaging was performed at the follow-up examination, including the magnetic resonance observation of cartilage repair tissue (MOCART) score. The mean KOOS and IKDC scores increased significantly ( p  < 0.01) from 50.3 and 37.4 points preoperatively to 90.1 and 79.4 postoperatively. The VAS score decreased from 7.8 to 2.3 points. Mean MOCART score at follow-up was 58.3 points. Cartilage repair of patellar lesions aided by a retraction system in a dry arthroscopy setup is a promising approach. Further studies are needed to evaluate this procedure and compare it to existing matrix implantation techniques. The level of evidence for the study is 4 (case series). Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

The reliability of four widely used patellar height ratios.

PubMed

van Duijvenbode, Dennis; Stavenuiter, Michel; Burger, Bart; van Dijke, Cees; Spermon, Jacco; Hoozemans, Marco

2016-03-01

The objective of this study was to evaluate the inter-observer reliability and the intra-observer reliability of four patellar height ratios: Insall-Salvati (IS), modified Insall-Salvati (MIS), Blackburne-Peel (BP) and Caton-Deschamps (CD). The patellar height ratios were assessed by four independent examiners using weight-bearing lateral knee radiographs in 30° flexion. Intra-class correlation coefficients and Fleiss' kappa's were determined. The inter-observer reliability was excellent for the IS and moderate for the other ratios. When the ratio values were categorized, the inter-observer reliability was strong for the IS, moderate for the MIS and BP, and poor for the CD. The intra-observer reliability was excellent for the IS, MIS and CD, and strong for the BP. When the ratio values were categorized, the intra-observer reliability was strong for the IS and MIS, and moderate for the other ratios. Although the IS showed best reliability, we advise to use the MIS as it showed the second best reliability but is, according to the literature, associated with better validity.

[TRANSOSSEOUS OSTEOSYNTHESIS OF LOWER EXTREMITIES BONES FRACTURES AND QUALITY OF LIFE OF PATIENTS IN THE TREATMENT PERIOD].

PubMed

Dyusupov, A; Dyusupov, A; Manarbekov, E; Bukatov, A; Serikbaev, A

2018-02-01

The aim of the study is a comparative analysis of the quality of life in the treatment of fractures of the bones of the lower extremities of various localizations using transosseous and submerged osteosynthesis. We examined 397 patients with injuries of the lower segment of the lower extremity (patellar fractures - 81, multiple bones fractures of the tibia - 84 and fractures of the ankles, accompanied by a dislocation of the foot - 232). Patients were distributed in the subgroups depending on the treatment. The main group was performed using transosseous osteosynthesis, the comparison group - submerged osteosynthesis. The quality of life was examined using a general questionnaire SF-36 and specialized KOOS (with patella fractures) and FOAS (fractures of the bones of the lower leg and ankles). In patients with all localizations of fractures the quality of life was exceeded in the subgroups of the transosseous osteosynthesis group over the parameters of the comparison group. The most significant differences with the use of specialized questionnaires were revealed 6-9 months after trauma with a tendency to leveling to the end of the study (1 year). A more pronounced excess of the quality of life in the main group was seen in fractures of the shin bones. The study of the quality of life allows us to recommend the use of transosseous osteosynthesis for the treatment of lower segment of the lower limb bone fractures.

Hyaluronic acid injections protect patellar tendon from detraining-associated damage.

PubMed

Frizziero, Antonio; Salamanna, Francesca; Giavaresi, Gianluca; Ferrari, Andrea; Martini, Lucia; Marini, Marina; Veicsteinas, Arsenio; Maffulli, Nicola; Masiero, Stefano; Fini, Milena

2015-09-01

Having previously demonstrated that detraining affects patellar tendon (PT) proteoglycan content and collagen fiber organization, we undertook the present study with two aims: to improve knowledge on the adaptation of PT and its enthesis to detraining from a histological and histomorphometric point of view, and to investigate the hypothesis that repeated peri-patellar injections of hyaluronic acid (HA) on detrained PT may reduce and limit detrained associated-damage. Twenty-four male Sprague-Dawley rats were divided into 3 groups: Untrained (n=6), Trained (n=6) (10 wks-treadmill) and Detrained (n=12). In the detrained rats, the left tendon was untreated while the right tendon received repeated peri-patellar injections of either HA or saline (NaCl). Structure and morphology of PTs (modified Movin score, tear density, collagen type I and III) and enthesis (cell morphology, chondrocyte cluster formation, tidemark integrity, matrix staining and vascularization) were evaluated. The left PT and enthesis of the Detrained groups showed altered structure and morphology with the highest Movin score values, the highest percentage of collagen III and the lowest of collagen I; the lowest score values were observed in the Trained and Detrained-HA groups. Detrained-NaCl PTs showed the highest collagen III and the lowest collagen I values with respect to Detrained-HA PTs. This study strengthens previously published data showing the alteration in tendon and enthesis morphology due to discontinuation of training, and provides new data showing that treatment with HA is effective in the maintenance of the structural properties of PT and enthesis in Detrained rats. Such beneficial effects could play a significant role in the management of conservative and rehabilitation strategies in athletes that change type, intensity and duration of training.

IDEAL 3D spoiled gradient echo of the articular cartilage of the knee on 3.0 T MRI: a comparison with conventional 3.0 T fast spin-echo T2 fat saturation image.

PubMed

Han, Chul Hee; Park, Hee Jin; Lee, So Yeon; Chung, Eun Chul; Choi, Seon Hyeong; Yun, Ji Sup; Rho, Myung Ho

2015-12-01

Many two-dimensional (2D) morphologic cartilage imaging sequences have disadvantages such as long acquisition time, inadequate spatial resolution, suboptimal tissue contrast, and image degradation secondary to artifacts. IDEAL imaging can overcome these disadvantages. To compare sound-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and quality of two different methods of imaging that include IDEAL 3D SPGR and 3.0-T FSE T2 fat saturation (FS) imaging and to evaluate the utility of IDEAL 3D SPGR for knee joint imaging. SNR and CNR of the patellar and femoral cartilages were measured and calculated. Two radiologists performed subjective scoring of all images for three measures: general image quality, FS, and cartilage evaluation. SNR and CNR values were compared by paired Student's t-tests. Mean SNRs of patellar and femoral cartilages were 90% and 66% higher, respectively, for IDEAL 3D SPGR. CNRs of patellar cartilages and joint fluids were 2.4 times higher for FSE T2 FS, and CNR between the femoral cartilage and joint fluid was 2.2 times higher for FSE T2 FS. General image quality and FS were superior using FSE T2 FS compared to those of IDEAL 3D SPGR imaging according to both readers, while cartilage evaluation was superior using IDEAL 3D SPGR. Additionally, cartilage injuries were more prominent in IDEAL 3D SPGR than in FSE T2FS according to both readers. IDEAL 3D SPGR images show excellent visualization of patellar and femoral cartilages in 3.0 T and can compensate for the weaknesses of FSE T2 FS in the evaluation of cartilage injuries. © The Foundation Acta Radiologica 2014.

Inter- and intra-rater reliability of patellofemoral kinematic and contact area quantification by fast spin echo MRI and correlation with cartilage health by quantitative T1ρ MRI☆

PubMed Central

Lau, Brian C.; Thuillier, Daniel U.; Pedoia, Valentina; Chen, Ellison Y.; Zhang, Zhihong; Feeley, Brian T.; Souza, Richard B.

2016-01-01

Background Patellar maltracking is a leading cause of patellofemoral pain syndrome (PFPS). The aim of this study was to determine the inter- and intra-rater reliability of a semi-automated program for magnetic resonance imaging (MRI) based patellofemoral kinematics. Methods Sixteen subjects (10 with PFPS [mean age 32.3; SD 5.2; eight females] and six controls without PFPS 19 [mean age 28.6; SD 2.8; three females]) participated in the study. One set of T2-weighted, fat-saturated fast spin-echo (FSE) MRIs were acquired from each subject in full extension and 30° of knee flexion. MRI including axial T1ρ relaxation time mapping sequences was also performed on each knee. Following image acquisitions, regions of interest for kinematic MRI, and patellar and trochlear cartilage were segmented and quantified with in-house designed spline- based MATLAB semi-automated software. Results Intraclass Correlations Coefficients (ICC) of calculated kinematic parameters were good to excellent, ICC > 0.8 in patellar flexion, rotation, tilt, and translation (anterior -posterior, medial -lateral, and superior -inferior), and contact area translation. Only patellar tilt in the flexed position and motion from extended to flexed state was significantly different between PFPS and control patients (p = 0.002 and p = 0.006, respectively). No significant correlations were identified between patellofemoral kinematics and contact area with T1ρ relaxation times. Conclusions A semi-automated, spline-based kinematic MRI technique for patellofemoral kinematic and contact area quantification is highly reproducible with the potential to help better understand the role of patellofemoral maltracking in PFPS and other knee disorders. PMID:26746045

Effects of upright weight bearing and the knee flexion angle on patellofemoral indices using magnetic resonance imaging in patients with patellofemoral instability.

PubMed

Becher, Christoph; Fleischer, Benjamin; Rase, Marten; Schumacher, Thees; Ettinger, Max; Ostermeier, Sven; Smith, Tomas

2017-08-01

This study analysed the effects of upright weight bearing and the knee flexion angle on patellofemoral indices, determined using magnetic resonance imaging (MRI), in patients with patellofemoral instability (PI). Healthy volunteers (control group, n = 9) and PI patients (PI group, n = 16) were scanned in an open-configuration MRI scanner during upright weight bearing and supine non-weight bearing positions at full extension (0° flexion) and at 15°, 30°, and 45° flexion. Patellofemoral indices included the Insall-Salvati Index, Caton-Deschamp Index, and Patellotrochlear Index (PTI) to determine patellar height and the patellar tilt angle (PTA), bisect offset (BO), and the tibial tubercle-trochlear groove (TT-TG) distance to assess patellar rotation and translation with respect to the femur and alignment of the extensor mechanism. A significant interaction effect of weight bearing by flexion angle was observed for the PTI, PTA, and BO for subjects with PI. At full extension, post hoc pairwise comparisons revealed a significant effect of weight bearing on the indices, with increased patellar height and increased PTA and BO in the PI group. Except for the BO, no such changes were seen in the control group. Independent of weight bearing, flexing the knee caused the PTA, BO, and TT-TG distance to be significantly reduced. Upright weight bearing and the knee flexion angle affected patellofemoral MRI indices in PI patients, with significantly increased values at full extension. The observations of this study provide a caution to be considered by professionals when treating PI patients. These patients should be evaluated clinically and radiographically at full extension and various flexion angles in context with quadriceps engagement. Explorative case-control study, Level III.

Association of childhood adiposity measures with adulthood knee cartilage defects and bone marrow lesions: a 25-year cohort study.

PubMed

Meng, T; Thayer, S; Venn, A; Wu, F; Cicuttini, F; March, L; Dwyer, T; Halliday, A; Cross, M; Laslett, L L; Jones, G; Ding, C; Antony, B

2018-05-25

To describe the associations between childhood adiposity measures and adulthood knee cartilage defects and bone marrow lesions (BMLs) measured 25 years later. 327 participants from the Australian Schools Health and Fitness Survey (ASHFS) of 1985 (aged 7-15 years) were followed up 25 years later (aged 31-41 years). Childhood measures (weight, height and skinfolds) were collected in 1985. Body mass index (BMI), overweight status and fat mass were calculated. Participants underwent 1.5 T knee magnetic resonance imaging (MRI) during 2008-2010, and cartilage defects and BMLs were scored from knee MRI scans. Log binomial regressions were used to examine the associations. Among 327 participants (47.1% females), 21 (6.4%) were overweight in childhood. Childhood adiposity measures were associated with the increased risk of adulthood patellar cartilage defects (Weight relative risk (RR) 1.05/kg, 95% confidence interval (CI) 1.01-1.09; BMI 1.10/kg/m 2 , 1.01-1.19; Overweight 2.22/yes, 1.21-4.08; fat mass 1.11/kg, 1.01-1.22), but not tibiofemoral cartilage defects. Childhood adiposity measures were not significantly associated with adulthood knee BMLs except for the association between childhood overweight status and adulthood patellar BMLs (RR 2.87/yes, 95% CI 1.10-7.53). These significant associations persisted after adjustment for corresponding adulthood adiposity measure. Childhood adiposity measures were associated with the increased risk of adulthood patellar cartilage defects and, to a lesser extent, BMLs, independent of adulthood adiposity measures. These results suggest that adiposity in childhood has long-term effects on patellar structural abnormalities in young adults. Copyright © 2018 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Predictors of treatment response to strengthening and stretching exercises for patellofemoral pain: An examination of patellar alignment.

PubMed

Peng, Hsien-Te; Song, Chen-Yi

2015-12-01

Closed kinetic chain and quadriceps strengthening, combined with flexibility exercises of the lower limb musculature, is a common treatment for patellofemoral pain syndrome (PFPS). The effectiveness has been well documented; however, very little is known about which factors predict treatment success. A total of 43 female subjects with PFPS participated in an eight-week progressive leg press (LP) strengthening and stretching exercise program. A decrease of 1.5 cm on a 10 cm visual analog scale (VAS) score was used as an indicator for treatment success. The baseline patellar tilt angle difference (PTA-d) due to quadriceps contraction prior to treatment was evaluated as a predictor of treatment success. The logistic regression and receiver operating characteristics (ROC) curve analysis were performed to investigate the predictive value of PTA-d. PTA-d could significantly predict the treatment success of LP strengthening and stretching exercises. The odds ratio (OR) for having an unsuccessful outcome was 1.19 (95% confidence interval (CI), 1.03-1.39, P<0.021) per degree increment of PTA-d. The most optimal cut-off value for the clinical discrimination of treatment success after LP strengthening and stretching exercise was -1.5° of PTA-d (sensitivity=0.74, specificity=0.71). The area under the ROC curve was 0.73 (standard error=0.08). Female patients with PFPS whose quadriceps contraction reduced the lateral patellar tilt prior to LP strengthening and stretching exercise treatment are more likely to experience pain relief. It seems clinically important to check dynamic patellar tilt characteristics before treatment to aid in clinical decision making. Copyright © 2014 Elsevier B.V. All rights reserved.

[Application of radiofrequency vaporization in arthroscopic treatment of patellofemoral joint disorders].

PubMed

Xuan, Tao; Xu, Bin; Xu, Honggang; Wang, Hao

2009-01-01

To explore the treatment of patellofemoral joint disorders with radiofrequency vaporization under arthroscopy. From June 2004 to June 2007, 86 cases of patellofemoral joint disorder (98 knees) were treated by lateral retinacular release or medial retinacular tighten added, and combined with bipolar radiofrequency chondroplasty under arthroscopy. There were 30 males (34 knees) and 56 females (64 knees), aging 15-68 years (mean 40 years). The locations were left in 42 cases, right in 32 cases, both sides in 12 cases. The disease course was 3 months to 6 years (mean 30.5 months). In 98 knees, there were 28 knees of static patellar tilt, 10 knees of static patellar subluxation, 45 knees of dynamic patellar tilt and 15 knees of dynamic patellar subluxation. The Lysholm knee score preoperatively was 57.72 +/- 8.86. The patellofemoral cartilage abnormality were classified according to the Outerbridge grade (18 knees of grade I, 36 knees of grade II, 32 knees of grade III and 12 knees of grade IV). The incisions healed by first intention without complications such as infection or hemarthrosis. Seventy-five cases (82 knees) were followed up 8-37 months (mean 20.6 months). One month after operation, the patellofemoral joint pain was relieved remarkably, the knee joint activity was good and the radiological outcomes was also satisfactory. Six months after operation, the Lysholm knee score was improved significantly in patients of grades I, II and III (P < 0.05), while there was no significant change in patients of grade IV (P > 0.05). The postoperative score was 69.95 +/- 5.42 (P < 0.05). Radiofrequency vaporization chondroplasty and soft tissue balance under arthroscopy are advantageous in terms of easy operation, less injury, slight reaction and have good effect on patellofemoral joint disorders.

Predictors for anterior pelvic tilt following surgical correction of flexed knee gait including patellar tendon shortening in children with cerebral palsy.

PubMed

Böhm, Harald; Hösl, Matthias; Döderlein, Leonhard

2017-05-01

Patellar tendon shortening procedure within single event multilevel surgeries was shown to improve crouch gait in Cerebral Palsy (CP) patients. However, one of the drawbacks associated to the correction of flexed knee gait may be increased pelvic anterior tilt with compensatory lumbar lordosis. Which CP patients are at risk for excessive anterior pelvic tilt following correction of flexed knee gait including patellar tendon shortening? 32 patients with CP between 8 and 18 years GMFCS I&II were included. They received patellar tendon shortenings within multilevel surgery. Patients with concomitant knee flexor lengthening were excluded. Gait analysis and clinical testing was performed pre- and 24.1 (SD=1.9) months postoperatively. Patients were subdivided into more/less than 5° increase in anterior pelvic tilt. Preoperative measures indicating m. rectus and m. psoas shortness, knee flexor over-length, hip extensor and abdominal muscle weakness and equinus gait were compared between groups. Stepwise multilinear regression of the response value increase in pelvic tilt during stance phase was performed from parameters that were significantly different between groups. 34% of patients showed more than 5° increased pelvic anterior tilt postoperatively. Best predictors for anterior pelvic tilt from preoperative measures were increased m. rectus tone and reduced hip extension during walking that explained together 39% of the variance in increase of anterior pelvic tilt. Every third patient showed considerable increased pelvic tilt following surgery of flexed knee gait. In particular patients with preoperative higher muscle tone in m. rectus and lower hip extension during walking were at risk and both features need to be addressed in the therapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Inter- and intra-rater reliability of patellofemoral kinematic and contact area quantification by fast spin echo MRI and correlation with cartilage health by quantitative T1ρ MRI.

PubMed

Lau, Brian C; Thuillier, Daniel U; Pedoia, Valentina; Chen, Ellison Y; Zhang, Zhihong; Feeley, Brian T; Souza, Richard B

2016-01-01

Patellar maltracking is a leading cause of patellofemoral pain syndrome (PFPS). The aim of this study was to determine the inter- and intra-rater reliability of a semi-automated program for magnetic resonance imaging (MRI) based patellofemoral kinematics. Sixteen subjects (10 with PFPS [mean age 32.3; SD 5.2; eight females] and six controls without PFPS 19 [mean age 28.6; SD 2.8; three females]) participated in the study. One set of T2-weighted, fat-saturated fast spin-echo (FSE) MRIs were acquired from each subject in full extension and 30° of knee flexion. MRI including axial T1ρ relaxation time mapping sequences was also performed on each knee. Following image acquisitions, regions of interest for kinematic MRI, and patellar and trochlear cartilage were segmented and quantified with in-house designed spline- based MATLAB semi-automated software. Intraclass Correlations Coefficients (ICC) of calculated kinematic parameters were good to excellent, ICC > 0.8 in patellar flexion, rotation, tilt, and translation (anterior -posterior, medial -lateral, and superior -inferior), and contact area translation. Only patellar tilt in the flexed position and motion from extended to flexed state was significantly different between PFPS and control patients (p=0.002 and p=0.006, respectively). No significant correlations were identified between patellofemoral kinematics and contact area with T1ρ relaxation times. A semi-automated, spline-based kinematic MRI technique for patellofemoral kinematic and contact area quantification is highly reproducible with the potential to help better understand the role of patellofemoral maltracking in PFPS and other knee disorders. Level IV. Published by Elsevier B.V.

[Treatment of septic olecranon and patellar bursitis by excision and vacuum-assisted closure therapy].

PubMed

Walter, G; Kemmerer, M; Hoffmann, R

2013-08-01

Treatment of septic olecranon and patellar bursitis differs considerably and is currently under discussion. We therefore performed a retrospective study of our patients with septic bursitis in the past 5 years. Between March 2007 and February 2012 we treated 79 patients with septic olecranon (n = 43) and patellar (n = 36) bursitis surgically: 61-males, 18 females, age 51 (range: 11-91) years. Four patients had not been treated before, 25 had suffered recurrences after 1-10 previous procedures, and 9 patients had not improved after conservative therapy. 34 patients presented with traumatic rupture or fistula of their bursae. In all cases we performed a radical bursectomy and vacuum-assisted therapy for 4 to 5 days. In addition, patients received systemic antibiotics. We phoned all patients and were successful in 57 cases (72 %). We questioned these patients for range of movement, limitations at work, pain, sensibility disorder, satisfaction with the result and further surgical procedures. In all cases we took tissue specimens for cultures, in 48 preparations histological examination was performed. Microbiological and histological results are discussed in detail. 40 patients were free of complaints, 15 complained of mild pain, 54 of 57 had unlimited range of motion. Minor discomforts at desk work were reported by 5 of 43 patients, 12 out of 36 patient reported discomfort when performing on their knees. There was no recurrence in the period of investigation. We recommend our treatment concept for septic olecranon and patellar bursitis because patient satisfaction is high and recurrences are reliably avoided. The soft tissue is spared, so that plastic covering procedures are seldom necessary. Georg Thieme Verlag KG Stuttgart · New York.

Ia Afferent input alters the recruitment thresholds and firing rates of single human motor units.

PubMed

Grande, G; Cafarelli, E

2003-06-01

Vibration of the patellar tendon recruits motor units in the knee extensors via excitation of muscle spindles and subsequent Ia afferent input to the alpha-motoneuron pool. Our first purpose was to determine if the recruitment threshold and firing rate of the same motor unit differed when recruited involuntarily via reflex or voluntarily via descending spinal pathways. Although Ia input is excitatory to the alpha-motoneuron pool, it has also been shown paradoxically to inhibit itself. Our second purpose was to determine if vibration of the patellar tendon during a voluntary knee extension causes a change in the firing rate of already recruited motor units. In the first protocol, 10 subjects voluntarily reproduced the same isometric force profile of the knee extensors that was elicited by vibration of the patellar tendon. Single motor unit recordings from the vastus lateralis (VL) were obtained with tungsten microelectrodes and unitary behaviour was examined during both reflex and voluntary knee extensions. Recordings from 135 single motor units showed that both recruitment thresholds and firing rates were lower during reflex contractions. In the second protocol, 7 subjects maintained a voluntary knee extension at 30 N for approximately 40-45 s. Three bursts of patellar tendon vibration were superimposed at regular intervals throughout the contraction and changes in the firing rate of already recruited motor units were examined. A total of 35 motor units were recorded and each burst of superimposed vibration caused a momentary reduction in the firing rates and recruitment of additional units. Our data provide evidence that Ia input modulates the recruitment thresholds and firing rates of motor units providing more flexibility within the neuromuscular system to grade force at low levels of force production.

The problem of chondromalacia patellae.

PubMed

Outerbridge, R E; Dunlop, J A

1975-01-01

Daily activity subjects the human patella to forces often several times the individual's body weight. Healthy cartilage can adjust to these forces if they are not too excessive, concentrated, or repetitive. Such abnormal stresses most frequently occur with the disturbance of normal patellar mechanical function. Chondromalacia patellae is the result common to a wide variety of unusual traumata. Treatment must be directed primarily not toward the damaged patellar cartilage but toward a correction of the mechanical abnormality causing it. Until proven otherwise, a young female complaining of knee joint pain, particularly if bilateral, should be considered as suffering from a subluxating patella, with or without chondromalacia patellae.

SURGICAL CORRECTION OF BILATERAL PATELLAR LUXATION IN AN AMERICAN BLACK BEAR CUB (URSUS AMERICANUS).

PubMed

Bennett, Katarina R; Desmarchelier, Marion R; Bailey, Trina R

2015-06-01

A wild orphaned male American black bear cub ( Ursus americanus ) presented with hind limb gait abnormalities and was found to have bilateral grade 3 laterally luxating patellas. There were no other significant abnormalities detected on neurologic, radiographic, or hematologic examinations. The trochlear grooves were deepened with a chondroplasty, and the redundant soft tissues imbricated. There was a marked improvement in the bear's gait postoperatively, with an apparent full return to function. To the authors' knowledge, patellar luxation has not been reported in the Ursidae family, and the success in this case suggests that this technique may be used in large wild or captive carnivore cubs.

Determination of reference values and frequency of occurrence of patella alta in German shepherd dogs: a retrospective study.

PubMed

Łojszczyk-Szczepaniak, Anna; Silmanowicz, Piotr; Komsta, Renata; Osiński, Zbigniew

2017-05-31

Patella alta and patella baja are important conditions underlying a predisposition to many joint diseases, including patellar luxation and patellar chondromalacia of the articular cartilage. The frequencies of patella alta and patella baja have not yet been determined. The objectives of this study were to determine the frequency of patella alta and to determine reference values to the position of the vertical patella according to two modified techniques of the Insall-Salvati method in a group of 65 German shepherd dogs (115 stifle joints). The upper limits of reference values for the normal vertical position of the patella were 1.79 and 2.13, depending on the method of measurement. A high prevalence of patella alta was observed in the group of German shepherd dogs. A correlation was demonstrated between the classification of dogs' joints in the patella alta group and the multiplied risk of canine hip dysplasia (CHD) through the estimation of odds ratios. Dogs with patella alta were healthy dogs that did not exhibit orthopaedic problems in the stifle joints. The results revealed that the risk of CHD is twice as high in dogs with higher patellar ligament length to patella length ratio.

[Arthroscopic reconstruction of anterior cruciate ligament with press-fit technique].

PubMed

Halder, A M

2010-08-01

Problems related to the use of interference screws for fixation of bone-patellar tendon-bone grafts for anterior cruciate ligament (ACL) replacement have led to increasing interest in press-fit techniques. Most of the described techniques use press-fit fixation on either the femoral or tibial side. Therefore an arthroscopic technique was developed which achieves bone-patellar tendon-bone graft fixation by press-fit on both sides without the need for supplemental fixation material. The first consecutive 40 patients were examined clinically with a KT-1000 arthrometer and radiologically after a mean of 28.7 months (range 20-40 months) postoperatively. The mean difference in side-to-side laxity was 1.3 mm (SD 2.2 mm) and the results according to the International Knee Documentation Committee (IKDC) score were as follows: 7 A, 28 B, 5 C, 0 D. The presented press-fit technique avoids all complications related to the use of interference screws. It achieves primary stable fixation of the bone-patellar tendon-bone graft thereby allowing early functional rehabilitation. However, fixation strength depends on bone quality and the arthroscopic procedure is demanding. The results showed reliable stabilization of the operated knees.

Effects of a peracetic acid disinfection protocol on the biocompatibility and biomechanical properties of human patellar tendon allografts.

PubMed

Lomas, R J; Jennings, L M; Fisher, J; Kearney, J N

2004-01-01

Patellar tendon allografts, retrieved from cadaveric human donors, are widely used for replacement of damaged cruciate ligaments. In common with other tissue allografts originating from cadaveric donors, there are concerns regarding the potential for disease transmission from the donor to the recipient. Additionally, retrieval and subsequent processing protocols expose the graft to the risk of environmental contamination. For these reasons, disinfection or sterilisation protocols are necessary for these grafts before they are used clinically. A high-level disinfection protocol, utilising peracetic acid (PAA), has been developed and investigated for its effects on the biocompatibility and biomechanics of the patellar tendon allografts. PAA disinfection did not render the grafts either cytotoxic or liable to provoke an inflammatory response as assessed in vitro . However, the protocol was shown to increase the size of gaps between the tendon fibres in the matrix and render the grafts more susceptible to digestion with collagenase. Biomechanical studies of the tendons showed that PAA treatment had no effect on the ultimate tensile stress or Young's modulus of the tendons, and that ultimate strain was significantly higher in PAA treated tendons.

Management of displaced comminuted patellar fracture with titanium cable cerclage.

PubMed

Yang, Li; Yueping, Ouyang; Wen, Yuan

2010-08-01

Management of a displaced comminuted patellar fracture is challenging. Tension band wiring and lag screw fixation are not suitable for such a fracture pattern. Stainless steel wiring with various configurations has been the mainstay of treatment. However, issues of loss of fixation and breakage of wire have not been resolved yet. Partial or total patellectomy is the last resort with a detrimental effect on quadriceps power. Braided titanium cable is stronger in tensile strength and better in fatigue resistance than the stainless steel monofilament wire, and the tension of fixation could be controlled by a graded instrument in its application. We used titanium cable to treat 21 consecutive patients with displaced comminuted patellar fracture. Patients were followed up for a mean period of 24 months (12 to 32 months). The mean score at the final follow-up was 27 points (25 to 30) using the Böstman method. There was no complication except breakage of one cable at the sixth week after the operation and the fracture had united despite the breakage. This technique is simple and effective for these difficult fractures and avoided prolonged immobilisation of the knee. Copyright 2010 Elsevier B.V. All rights reserved.

Anatomically remote muscle contraction facilitates patellar tendon reflex reinforcement while mental activity does not: a within-participants experimental trial.

PubMed

Passmore, Steven R; Bruno, Paul A

2012-09-07

The Jendrassik maneuver (JM) is a remote facilitation muscular contraction shown to affect amplitude and temporal components of the human stretch reflex. Conflicting theoretical models exist regarding the neurological mechanism related to its ability to reinforce reflex parameters. One mechanism involves the gamma motoneurons of the fusimotor system, which are subject to both physical and mental activity. A second mechanism describes reduced alpha motoneuron presynaptic inhibition, which is not subject to mental activity. In the current study, we determined if mental activity could be used to create a reflex facilitation comparable to a remote muscle contraction. Using a within-participants design, we investigated the relative effect of the JM and a successfully employed mental task (Stroop task) on the amplitude and temporal components of the patellar tendon reflex. We found that the addition of mental activity had no influence on the patellar tendon reflex parameters measured, while the JM provided facilitation (increased reflex amplitude, decreased total reflex time). The findings from this study support the view that the mechanism for the JM is a reduction in presynaptic inhibition of alpha motoneurons as it is influenced by physical and not mental activity.

Arthroscopic anterior cruciate ligament reconstruction using the double press- fit technique: an alternative to interference screw fixation.

PubMed

Halder, Andreas M; Ludwig, Silke; Neumann, Wolfram

2002-01-01

Patellar tendon autograft fixation in arthroscopic anterior cruciate ligament reconstruction is commonly accomplished using interference screws. However, improper insertion of the screws may reduce primary stability, injure the posterior femoral cortex, or displace hardware into the joint. Even if placed properly, metallic screws interfere with postoperative magnetic resonance imaging. In case of revision surgery, removing screws may be difficult and leaves bone defects. Retrospective study. An arthroscopic technique was developed that achieves patellar tendon autograft fixation by press-fit without any supplemental internal fixation. Forty patients were examined clinically and by KT-1000 arthrometer 28.7 months (range, 22 to 40 months) postoperatively. The mean difference in side-to-side laxity was 1.3 mm (SD 2.2) and the results according to the IKDC score were as follows: 7 A, 28 B, 5 C, and 0 D. The double press-fit technique we present avoids all complications related to the use of interference screws and creates an ideal environment for osseous integration of the bone-patellar tendon-bone autograft. Concurrently, it achieves a stable fixation of the autograft and allows early functional rehabilitation. However, fixation strength depends on bone quality and the arthroscopic procedure is demanding.

Computer-aided diagnosis in phase contrast imaging X-ray computed tomography for quantitative characterization of ex vivo human patellar cartilage.

PubMed

Nagarajan, Mahesh B; Coan, Paola; Huber, Markus B; Diemoz, Paul C; Glaser, Christian; Wismuller, Axel

2013-10-01

Visualization of ex vivo human patellar cartilage matrix through the phase contrast imaging X-ray computed tomography (PCI-CT) has been previously demonstrated. Such studies revealed osteoarthritis-induced changes to chondrocyte organization in the radial zone. This study investigates the application of texture analysis to characterizing such chondrocyte patterns in the presence and absence of osteoarthritic damage. Texture features derived from Minkowski functionals (MF) and gray-level co-occurrence matrices (GLCM) were extracted from 842 regions of interest (ROI) annotated on PCI-CT images of ex vivo human patellar cartilage specimens. These texture features were subsequently used in a machine learning task with support vector regression to classify ROIs as healthy or osteoarthritic; classification performance was evaluated using the area under the receiver operating characteristic curve (AUC). The best classification performance was observed with the MF features perimeter (AUC: 0.94 ±0.08 ) and "Euler characteristic" (AUC: 0.94 ±0.07 ), and GLCM-derived feature "Correlation" (AUC: 0.93 ±0.07). These results suggest that such texture features can provide a detailed characterization of the chondrocyte organization in the cartilage matrix, enabling classification of cartilage as healthy or osteoarthritic with high accuracy.

Healing of donor site in bone-tendon-bone ACL reconstruction accelerated with plasma rich in growth factors: a randomized clinical trial.

PubMed

Seijas, Roberto; Rius, Marta; Ares, Oscar; García-Balletbó, Montserrat; Serra, Iván; Cugat, Ramón

2015-04-01

To determine whether the use of plasma rich in growth factors accelerates healing of the donor site in bone-tendon-bone anterior cruciate ligament (ACL) reconstruction (patellar graft). The use of the patellar graft presents post-operative problems such as anterior knee pain, which limits its use and leads to preference being taken for alternative grafts. A double-blind, randomized, clinical trial was performed comparing two groups of patients who underwent ACL reconstruction using patellar tendon graft and comparing the use of plasma rich in growth factors at the donor site after graft harvest in terms of local regeneration by ultrasound assessment. The plasma rich in growth factors group shows earlier donor site regeneration in comparison with the control group (2 months earlier), with significant differences in the first 4 months of the follow-up. The application of plasma rich in growth factors shows accelerated tissue regeneration processes with respect to the control group. This fact, together with the previously published with similar conclusions, can create a knowledge basis in order to set out new recovery guidelines following ACL reconstruction. Therapeutic study, Level I.

Autologous platelet-rich plasma gel to reduce donor-site morbidity after patellar tendon graft harvesting for anterior cruciate ligament reconstruction: a randomized, controlled clinical study.

PubMed

Cervellin, M; de Girolamo, L; Bait, C; Denti, M; Volpi, P

2012-01-01

Bone-patellar tendon-bone technique (BPTB) for anterior cruciate ligament injuries is associated with a higher risk of donor-site morbidity. To evaluate whether platelet-rich plasma (PRP), due to its anti-inflammatory properties and capacity to stimulate tissue regeneration, was able to reduce the anterior knee pain, the kneeling pain, and donor-site morbidity, as evidenced by evaluation of VISA and VAS scoring scales and MRI analysis of the tendon and bone defect, we performed a clinical randomized controlled study where PRP gel was applied to donor site after ACL reconstruction with BPTB. Forty young athletes with the indication of ACL reconstruction with patellar tendon grafts were randomly assigned to group A (n = 20 patients, control group) or group B (n = 20 patients, PRP group). The autologous PRP gel was applied to both the patellar and tendon bone plug harvest site and stabilized by the peritenon suture. At 12-month follow-up, all patients underwent clinical examination and VAS and VISA questionnaires, respectively, evaluating the average daily pain of the knee and the pain during particular activities involving the knee, were filled. MRI at the same time point was also performed. VISA scores were significantly higher in the patients treated with PRP (84.5 ± 11.8 and 97.8 ± 2.5 for group A and for group B; P = 0.041), whereas no significant difference in postoperative VAS scores between the two groups was observed (1 ± 1.4 and 0.6 ± 0.9 for group A and group B, n.s.). In 85% of PRP group patients, the tibial and patellar bone defect was satisfactorily filled by new bony tissue (>70% of bone gap filled), whereas this percentage was just of 60% in control group patients, but this difference was not statistically significant. The study shows the usefulness of PRP in reducing subjective pain at the donor-site level after ACL reconstruction with BPTB. However, this approach deserves further investigations to confirm PRP efficacy and to elucidate its mechanism of action. Prospective randomized controlled study, Level I.

Contour interpolated radial basis functions with spline boundary correction for fast 3D reconstruction of the human articular cartilage from MR images

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

Javaid, Zarrar; Unsworth, Charles P., E-mail: c.unsworth@auckland.ac.nz; Boocock, Mark G.

2016-03-15

Purpose: The aim of this work is to demonstrate a new image processing technique that can provide a “near real-time” 3D reconstruction of the articular cartilage of the human knee from MR images which is user friendly. This would serve as a point-of-care 3D visualization tool which would benefit a consultant radiologist in the visualization of the human articular cartilage. Methods: The authors introduce a novel fusion of an adaptation of the contour method known as “contour interpolation (CI)” with radial basis functions (RBFs) which they describe as “CI-RBFs.” The authors also present a spline boundary correction which further enhancesmore » volume estimation of the method. A subject cohort consisting of 17 right nonpathological knees (ten female and seven male) is assessed to validate the quality of the proposed method. The authors demonstrate how the CI-RBF method dramatically reduces the number of data points required for fitting an implicit surface to the entire cartilage, thus, significantly improving the speed of reconstruction over the comparable RBF reconstruction method of Carr. The authors compare the CI-RBF method volume estimation to a typical commercial package (3D DOCTOR), Carr’s RBF method, and a benchmark manual method for the reconstruction of the femoral, tibial, and patellar cartilages. Results: The authors demonstrate how the CI-RBF method significantly reduces the number of data points (p-value < 0.0001) required for fitting an implicit surface to the cartilage, by 48%, 31%, and 44% for the patellar, tibial, and femoral cartilages, respectively. Thus, significantly improving the speed of reconstruction (p-value < 0.0001) by 39%, 40%, and 44% for the patellar, tibial, and femoral cartilages over the comparable RBF model of Carr providing a near real-time reconstruction of 6.49, 8.88, and 9.43 min for the patellar, tibial, and femoral cartilages, respectively. In addition, it is demonstrated how the CI-RBF method matches the volume estimation of a typical commercial package (3D DOCTOR), Carr’s RBF method, and a benchmark manual method for the reconstruction of the femoral, tibial, and patellar cartilages. Furthermore, the performance of the segmentation method used for the extraction of the femoral, tibial, and patellar cartilages is assessed with a Dice similarity coefficient, sensitivity, and specificity measure providing high agreement to manual segmentation. Conclusions: The CI-RBF method provides a fast, accurate, and robust 3D model reconstruction that matches Carr’s RBF method, 3D DOCTOR, and a manual benchmark method in accuracy and significantly improves upon Carr’s RBF method in data requirement and computational speed. In addition, the visualization tool has been designed to quickly segment MR images requiring only four mouse clicks per MR image slice.« less

Multiscale modeling of dislocation-precipitate interactions in Fe: From molecular dynamics to discrete dislocations.

PubMed

Lehtinen, Arttu; Granberg, Fredric; Laurson, Lasse; Nordlund, Kai; Alava, Mikko J

2016-01-01

The stress-driven motion of dislocations in crystalline solids, and thus the ensuing plastic deformation process, is greatly influenced by the presence or absence of various pointlike defects such as precipitates or solute atoms. These defects act as obstacles for dislocation motion and hence affect the mechanical properties of the material. Here we combine molecular dynamics studies with three-dimensional discrete dislocation dynamics simulations in order to model the interaction between different kinds of precipitates and a 1/2〈111〉{110} edge dislocation in BCC iron. We have implemented immobile spherical precipitates into the ParaDis discrete dislocation dynamics code, with the dislocations interacting with the precipitates via a Gaussian potential, generating a normal force acting on the dislocation segments. The parameters used in the discrete dislocation dynamics simulations for the precipitate potential, the dislocation mobility, shear modulus, and dislocation core energy are obtained from molecular dynamics simulations. We compare the critical stresses needed to unpin the dislocation from the precipitate in molecular dynamics and discrete dislocation dynamics simulations in order to fit the two methods together and discuss the variety of the relevant pinning and depinning mechanisms.

A continuum theory of edge dislocations

NASA Astrophysics Data System (ADS)

Berdichevsky, V. L.

2017-09-01

Continuum theory of dislocation aims to describe the behavior of large ensembles of dislocations. This task is far from completion, and, most likely, does not have a "universal solution", which is applicable to any dislocation ensemble. In this regards it is important to have guiding lines set by benchmark cases, where the transition from a discrete set of dislocations to a continuum description is made rigorously. Two such cases have been considered recently: equilibrium of dislocation walls and screw dislocations in beams. In this paper one more case is studied, equilibrium of a large set of 2D edge dislocations placed randomly in a 2D bounded region. The major characteristic of interest is energy of dislocation ensemble, because it determines the structure of continuum equations. The homogenized energy functional is obtained for the periodic dislocation ensembles with a random contents of the periodic cell. Parameters of the periodic structure can change slowly on distances of order of the size of periodic cells. The energy functional is obtained by the variational-asymptotic method. Equilibrium positions are local minima of energy. It is confirmed the earlier assertion that energy density of the system is the sum of elastic energy of averaged elastic strains and microstructure energy, which is elastic energy of the neutralized dislocation system, i.e. the dislocation system placed in a constant dislocation density field making the averaged dislocation density zero. The computation of energy is reduced to solution of a variational cell problem. This problem is solved analytically. The solution is used to investigate stability of simple dislocation arrays, i.e. arrays with one dislocation in the periodic cell. The relations obtained yield two outcomes: First, there is a state parameter of the system, dislocation polarization; averaged stresses affect only dislocation polarization and cannot change other characteristics of the system. Second, the structure of dislocation phase space is strikingly simple. Dislocation phase space is split in a family of subspaces corresponding to constant values of dislocation polarizations; in each equipolarization subspace there are many local minima of energy; for zero external stresses the system is stuck in a local minimum of energy; for non-zero slowly changing external stress, dislocation polarization evolves, while the system moves over local energy minima of equipolarization subspaces. Such a simple picture of dislocation dynamics is due to the presence of two time scales, slow evolution of dislocation polarization and fast motion of the system over local minima of energy. The existence of two time scales is justified for a neutral system of edge dislocations.

Dislocation evolution in 316 L stainless steel during multiaxial ratchetting deformation

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

Dong Yawei; Kang Guozheng, E-mail: guozhengkang@yahoo.com.cn; Liu Yujie

2012-03-15

Dislocation patterns and their evolutions in 316 L stainless steel during the multiaxial ratchetting deformation were observed by transmission electron microscopy (TEM). The microscopic observations indicate that the dislocation evolution presented during the multiaxial ratchetting with four kinds of multiaxial loading paths is similar to that in the uniaxial case [G. Z. Kang et al., Mater Sci Eng A 527 (2010) 5952]. That is, dislocation networks and dislocation tangles are formed quickly by the multiple-slip and cross-slip of dislocation activated by applied multiaxial stress; and then polarized patterns such as dislocation walls and elongated incipient dislocation cells are formed atmore » the last stage of multiaxial ratchetting. The dislocation patterns evolve more quickly from the modes at low dislocation density to the ones at high density during the multiaxial ratchetting than that in the uniaxial case, and some traces of multiple-slip are observed in the multiaxial ones. The dislocation evolution during the multiaxial ratchetting deformation is summarized by comparing the observed dislocation patterns with those presented in the multiaxial strain-controlled and symmetrical stress-controlled cyclic tests. The multiaxial ratchetting of 316 L stainless steel can be microscopically and qualitatively explained by the observed evolution of dislocation patterns. - Highlights: Black-Right-Pointing-Pointer Dislocation patterns change from lines and nets to tangles, walls and cells. Black-Right-Pointing-Pointer Dislocation patterns evolve quicker in the multiaxial case. Black-Right-Pointing-Pointer Aligned dislocation arrays and some traces of multiple slips are observed. Black-Right-Pointing-Pointer Heterogeneous dislocation patterns result in the multiaxial ratchetting.« less

Worker Dislocation. Case Studies of Causes and Cures.

ERIC Educational Resources Information Center

Cook, Robert F., Ed.

Case studies were made of the following dislocated worker programs: Cummins Engine Company Dislocated Worker Project; GM-UAW Metropolitan Pontiac Retraining and Employment Program; Minnesota Iron Range Dislocated Worker Project; Missouri Dislocated Worker Program Job Search Assistance, Inc.; Hillsborough, North Carolina, Dislocated Worker Project;…

Column-by-column observation of dislocation motion in CdTe: Dynamic scanning transmission electron microscopy

NASA Astrophysics Data System (ADS)

Li, Chen; Zhang, Yu-Yang; Pennycook, Timothy J.; Wu, Yelong; Lupini, Andrew R.; Paudel, Naba; Pantelides, Sokrates T.; Yan, Yanfa; Pennycook, Stephen J.

2016-10-01

The dynamics of partial dislocations in CdTe have been observed at the atomic scale using aberration-corrected scanning transmission electron microscopy (STEM), allowing the mobility of different dislocations to be directly compared: Cd-core Shockley partial dislocations are more mobile than Te-core partials, and dislocation cores with unpaired columns have higher mobility than those without unpaired columns. The dynamic imaging also provides insight into the process by which the dislocations glide. Dislocations with dangling bonds on unpaired columns are found to be more mobile because the dangling bonds mediate the bond exchanges required for the dislocations to move. Furthermore, a screw dislocation has been resolved to dissociate into a Shockley partial-dislocation pair along two different directions, revealing a way for the screw dislocation to glide in the material. The results show that dynamic STEM imaging has the potential to uncover the details of dislocation motion not easily accessible by other means.

Early history of operative treatment of patellar fractures.

PubMed

Bartoníček, Jan; Rammelt, Stefan

2015-11-01

The presented overview shows that the first efforts to address patellar fractures by operative treatment, although sporadic, emerged in the pre-antiseptic era. Introduction of Lister's antiseptic method in Great Britain, Germany and the USA in 1877-1882 contributed to a new, progressive trend in the treatment of fractures of the patella as well as of other bones. The authors, using Lister's antiseptic method, evaluated three basic aspects in their operations, namely healing of the surgical wound without infective complications, achievement of bony union and a good functional outcome, i.e. restoring the range of motion in the knee, even if limited in most cases. The majority of them used a longitudinal incision and fixation by a silver wire.

Free Bone Plug Quadriceps Tendon Harvest and Suspensory Button Attachment for Anterior Cruciate Ligament Reconstruction.

PubMed

Todor, Adrian; Caterev, Sergiu; Nistor, Dan Viorel; Khallouki, Youssef

2016-06-01

The most commonly used autografts for anterior cruciate ligament reconstruction are the bone-patellar tendon-bone and hamstring tendons. Each has its advantages and limitations. The bone-patellar tendon-bone autograft can lead to more donor-site morbidity, and the hamstring autograft can be unpredictable in size. The quadriceps tendon, with or without a bone block, has been described as an alternative graft source and has been used especially in revision cases, but in recent years, it has attracted attention even for primary cases. We report a technique for harvesting a free bone quadriceps tendon graft and attaching an extracortical button for femoral fixation for anterior cruciate ligament reconstruction.

Habitual dislocation of patella: A review

PubMed Central

Batra, Sumit; Arora, Sumit

2014-01-01

Habitual dislocation of patella is a condition where the patella dislocates whenever the knee is flexed and spontaneously relocates with extension of the knee. It is also termed as obligatory dislocation as the patella dislocates completely with each flexion and extension cycle of the knee and the patient has no control over the patella dislocating as he or she moves the knee1. It usually presents after the child starts to walk, and is often well tolerated in children, if it is not painful. However it may present in childhood with dysfunction and instability. Very little literature is available on habitual dislocation of patella as most of the studies have combined cases of recurrent dislocation with habitual dislocation. Many different surgical techniques have been described in the literature for the treatment of habitual dislocation of patella. No single procedure is fully effective in the surgical treatment of habitual dislocation of patella and a combination of procedures is recommended. PMID:25983506

Atomic-scale investigation of point defects and hydrogen-solute atmospheres on the edge dislocation mobility in alpha iron

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

Bhatia, M. A.; Solanki, K. N., E-mail: kiran.solanki@asu.edu; Groh, S.

2014-08-14

In this study, we present atomistic mechanisms of 1/2 [111](11{sup ¯}0) edge dislocation interactions with point defects (hydrogen and vacancies) and hydrogen solute atmospheres in body centered cubic (bcc) iron. In metals such as iron, increases in hydrogen concentration can increase dislocation mobility and/or cleavage-type decohesion. Here, we first investigate the dislocation mobility in the presence of various point defects, i.e., change in the frictional stress as the edge dislocation interacts with (a) vacancy, (b) substitutional hydrogen, (c) one substitutional and one interstitial hydrogen, (d) interstitial hydrogen, (e) vacancy and interstitial hydrogen, and (f) two interstitial hydrogen. Second, we examinemore » the role of a hydrogen-solute atmosphere on the rate of local dislocation velocity. The edge dislocation simulation with a vacancy in the compression side of the dislocation and an interstitial hydrogen atom at the tension side exhibit the strongest mechanical response, suggesting a higher potential barrier and hence, the higher frictional stress (i.e., ∼83% higher than the pure iron Peierls stress). In the case of a dislocation interacting with a vacancy on the compressive side, the vacancy binds with the edge dislocation, resulting in an increase in the friction stress of about 28% when compared with the Peierls stress of an edge dislocation in pure iron. Furthermore, as the applied strain increases, the vacancy migrates through a dislocation transportation mechanism by attaining a velocity of the same order as the dislocation velocity. For the case of the edge dislocation interacting with interstitial hydrogen on the tension side, the hydrogen atom jumps through one layer perpendicular to the glide plane during the pinning-unpinning process. Finally, our simulation of dislocation interactions with hydrogen show first an increase in the local dislocation velocity followed by a pinning of the dislocation core in the atmosphere, resulting in resistance to dislocation motion as the dislocation moves though the hydrogen-solute atmospheres. With this systematic, atomistic study of the edge dislocation with various point defects, we show significant increase in obstacle strengths in addition to an increase in the local dislocation velocity during interaction with solute atmospheres. The results have implications for constitutive development and modeling of the hydrogen effect on dislocation mobility and deformation in metals.« less

[Classification and Treatment of Sacroiliac Joint Dislocation].

PubMed

Tan, Zhen; Huang, Zhong; Li, Liang; Meng, Wei-Kun; Liu, Lei; Zhang, Hui; Wang, Guang-Lin; Huang, Fu-Guo

2017-09-01

To develop a renewed classification and treatment regimen for sacroiliac joint dislocation. According to the direction of dislocation of sacroiliac joint,combined iliac,sacral fractures,and fracture morphology,sacroiliac joint dislocation was classified into 4 types. Type Ⅰ (sacroiliac anterior dislocation): main fracture fragments of posterior iliac wing dislocated in front of sacroiliac joint. Type Ⅱ (sacroiliac posterior dislocation): main fracture fragments of posterior iliac wing dislocated in posterior of sacroiliac joint. Type Ⅲ (Crescent fracturedislocation of the sacroiliac joint): upward dislocation of posterior iliac wing with oblique fracture through posterior iliac wing. Type ⅢA: a large crescent fragment and dislocation comprises no more than onethird of sacroiliac joint,which is typically inferior. Type ⅢB: intermediatesize crescent fragment and dislocation comprises between one and twothirds of joint. Type ⅢC: a small crescent fragment where dislocation comprises most,but not the entire joint. Different treatment regimens were selected for different types of fractures. Treatment for type Ⅰ sacroiliac joint dislocation: anterior iliac fossa approach pry stripping reset; sacroiliac joint fixed with sacroiliac screw through percutaneous. Treatment for type Ⅱ sacroiliac joint dislocation: posterior sacroiliac joint posterior approach; sacroiliac joint fixed with sacroiliac screw under computer guidance. Treatment for type ⅢA and ⅢB sacroiliac joint dislocation: posterior sacroiliac joint approach; sacroiliac joint fixed with reconstruction plate. Treatment for type ⅢC sacroiliac joint dislocation: sacroiliac joint closed reduction; sacroiliac joint fixed with sacroiliac screw through percutaneous. Treatment for type Ⅳ sacroiliac joint dislocation: posterior approach; sacroiliac joint fixed with spinal pelvic fixation. Results of 24 to 72 months patient follow-up (mean 34.5 months): 100% survival,100% wound healing,and 100% fracture healing. Two cases were identified as type Ⅰ sacroiliac joint dislocation,including one with coexistence of nerve injury. Patients recovered completely 12 months after surgery. Eight cases were identified as type Ⅱ sacroiliac joint dislocation; none had obvious nerve injury during treatments. Twelve cases were identified as type Ⅲ sacroiliac joint dislocation,including one with coexistence of nerve injury. Patients recovered completely 12 months after surgery. Three cases were identified as type Ⅳ sacroiliac joint dislocation with coexistence of nerve injury. Two patients fully recovered 12 months after surgery. One had partial recovery of neurological function. The classification and treatment regimen for sacroiliac joint dislocation have achieved better therapeutic effect,which is worth promoting.

Impact of screw and edge dislocations on the thermal conductivity of individual nanowires and bulk GaN: a molecular dynamics study.

PubMed

Termentzidis, Konstantinos; Isaiev, Mykola; Salnikova, Anastasiia; Belabbas, Imad; Lacroix, David; Kioseoglou, Joseph

2018-02-14

We report the thermal transport properties of wurtzite GaN in the presence of dislocations using molecular dynamics simulations. A variety of isolated dislocations in a nanowire configuration are analyzed and found to considerably reduce the thermal conductivity while impacting its temperature dependence in a different manner. Isolated screw dislocations reduce the thermal conductivity by a factor of two, while the influence of edge dislocations is less pronounced. The relative reduction of thermal conductivity is correlated with the strain energy of each of the five studied types of dislocations and the nature of the bonds around the dislocation core. The temperature dependence of the thermal conductivity follows a physical law described by a T -1 variation in combination with an exponent factor that depends on the material's nature, type and the structural characteristics of the dislocation core. Furthermore, the impact of the dislocation density on the thermal conductivity of bulk GaN is examined. The variation and absolute values of the total thermal conductivity as a function of the dislocation density are similar for defected systems with both screw and edge dislocations. Nevertheless, we reveal that the thermal conductivity tensors along the parallel and perpendicular directions to the dislocation lines are different. The discrepancy of the anisotropy of the thermal conductivity grows with increasing density of dislocations and it is more pronounced for the systems with edge dislocations. Besides the fundamental insights of the presented results, these could also be used for the identification of the type of dislocations when one experimentally obtains the evolution of thermal conductivity with temperature since each type of dislocation has a different signature, or one could extract the density of dislocations with a simple measurement of thermal anisotropy.

3D discrete dislocation dynamics study of creep behavior in Ni-base single crystal superalloys by a combined dislocation climb and vacancy diffusion model

NASA Astrophysics Data System (ADS)

Gao, Siwen; Fivel, Marc; Ma, Anxin; Hartmaier, Alexander

2017-05-01

A three-dimensional (3D) discrete dislocation dynamics (DDD) creep model is developed to investigate creep behavior under uniaxial tensile stress along the crystallographic [001] direction in Ni-base single crystal superalloys, which takes explicitly account of dislocation glide, climb and vacancy diffusion, but neglects phase transformation like rafting of γ‧ precipitates. The vacancy diffusion model takes internal stresses by dislocations and mismatch strains into account and it is coupled to the dislocation dynamics model in a numerically efficient way. This model is helpful for understanding the fundamental creep mechanisms in superalloys and clarifying the effects of dislocation glide and climb on creep deformation. In cases where the precipitate cutting rarely occurs, e.g. due to the high anti-phase boundary energy and the lack of superdislocations, the dislocation glide in the γ matrix and the dislocation climb along the γ/γ‧ interface dominate plastic deformation. The simulation results show that a high temperature or a high stress both promote dislocation motion and multiplication, so as to cause a large creep strain. Dislocation climb accelerated by high temperature only produces a small plastic strain, but relaxes the hardening caused by the filling γ channels and lets dislocations further glide and multiply. The strongest variation of vacancy concentration occurs in the horizontal channels, where more mixed dislocations exit and tend to climb. The increasing internal stresses due to the increasing dislocation density are easily overcome by dislocations under a high external stress that leads to a long-term dislocation glide accompanied by multiplication.

Sleeve fracture of the adult patella: Case report and review of the literature.

PubMed

Xie, Linjun; Xu, Hong; Zhang, Lizhi; Xu, Rong; Guo, Yingkun

2017-08-01

The patellar fractures are common in adults, but rare in children. As a particular type of patellar fracture, however, sleeve fractures are almost always limited to children in the under 16's group. Herein, we report a rare case of a 19-year-old healthy adult female who presented sleeve fracture at the superior pole of the left patella. The clinical and radiological features are found including joint effusion, anterior tilt of the patella and a shell of bone lying proximally to the patella. Computed tomography and magnetic resonance imaging examination have been performed to further confirm the diagnosis of sleeve fracture, rupture of the quadriceps tendon and the cartilaginous injury. Under general anaesthesia, she underwent open surgical procedures for reconstituting anatomically the fracture and repairing the rupture of the quadriceps tendon. Six months after the operation, she could fully use her left knee without any pain and disability. Sleeve fractures of the patellar in adults are extremely rare, and our case is of interest for the first time occurring in healthy female adults. Our case report and literature review was aim to describe the clinic and imaging characteristics of superior pole sleeve fractures in adults, and highlight that physicians must be aware of this entity in adults so as to reduce misdiagnosis due to unfamiliarity.

Effect of alignment perturbations in a trans-tibial prosthesis user: A pilot study.

PubMed

Courtney, Anna; Orendurff, Michael S; Buis, Arjan

2016-04-01

A recurring complication in trans-tibial prosthetic limb users is "poor socket fit" with painful residuum-socket interfaces, a consequence of excess pressure. This is due to both poor socket fit and poor socket alignment; however, the interaction of these factors has not been quantified. Through evaluation of kinetic data this study aimed to articulate an interaction uniting socket design, alignment and interface pressures. The results will help to refine future studies and will hopefully help determine whether sockets can be designed, fitted and aligned to maximize mobility whilst minimizing injurious forces. Interface pressures were recorded throughout ambulation in one user with "optimal (reference) alignment" followed by 5 malalignments in a patellar tendon-bearing and a hydrocast socket. Marked differences in pressure distribution were discovered when equating the patellar tendon-bearing against the hydrocast socket and when comparing interface pressures from reference with offset alignment. Patellar tendon-bearing sockets were found to be more sensitive to alignment perturbations than hydrocast sockets. A complex interaction was found, with the most prominent finding demonstrating the requisite for attainment of optimal alignment: a translational alignment error of 10 mm can increase maximum peak pressures by 227% (mean 17.5%). Refinements for future trials are described and the necessity for future research into socket design, alignment and interface pressures has been estabilished.

Interfacial dislocations in (111) oriented (Ba 0.7Sr 0.3)TiO 3 films on SrTiO 3 single crystal

DOE PAGES

Shen, Xuan; Yamada, Tomoaki; Lin, Ruoqian; ...

2015-10-08

In this study, we have investigated the interfacial structure of epitaxial (Ba,Sr)TiO 3 films grown on (111)-oriented SrTiO 3 single-crystal substrates using transmission electron microscopy (TEM) techniques. Compared with the (100) epitaxial perovskite films, we observe dominant dislocation half-loop with Burgers vectors of a<110> comprised of a misfit dislocation along <112>, and threading dislocations along <110> or <100>. The misfit dislocation with Burgers vector of a <110> can dissociate into two ½ a <110> partial dislocations and one stacking fault. We found the dislocation reactions occur not only between misfit dislocations, but also between threading dislocations. Via three-dimensional electron tomography,more » we retrieved the configurations of the threading dislocation reactions. The reactions between threading dislocations lead to a more efficient strain relaxation than do the misfit dislocations alone in the near-interface region of the (111)-oriented (Ba 0.7Sr 0.3)TiO 3 films.« less

Dislocation mechanisms in stressed crystals with surface effects

NASA Astrophysics Data System (ADS)

Wu, Chi-Chin; Crone, Joshua; Munday, Lynn; Discrete Dislocation Dynamics Team

2014-03-01

Understanding dislocation properties in stressed crystals is the key for important processes in materials science, including the strengthening of metals and the stress relaxation during the growth of hetero-epitaxial structures. Despite existing experimental approaches and theories, many dislocation mechanisms with surface effects still remain elusive in experiments. Even though discrete dislocation dynamics (DDD) simulations are commonly employed to study dislocations, few demonstrate sufficient computational capabilities for massive dislocations with the combined effects of surfaces and stresses. Utilizing the Army's newly developed FED3 code, a DDD computation code coupled with finite elements, this work presents several dislocation mechanisms near different types of surfaces in finite domains. Our simulation models include dislocations in a bended metallic cantilever beam, near voids in stressed metals, as well as threading and misfit dislocations in as-grown semiconductor epitaxial layers and their quantitative inter-correlations to stress relaxation and surface instability. Our studies provide not only detailed physics of individual dislocation mechanisms, but also important collective dislocation properties such as dislocation densities and strain-stress profiles and their interactions with surfaces.

Recombination properties of dislocations in GaN

NASA Astrophysics Data System (ADS)

Yakimov, Eugene B.; Polyakov, Alexander Y.; Lee, In-Hwan; Pearton, Stephen J.

2018-04-01

The recombination activity of threading dislocations in n-GaN with different dislocation densities and different doping levels was studied using electron beam induced current (EBIC). The recombination velocity on a dislocation, also known as the dislocation recombination strength, was calculated. The results suggest that dislocations in n-GaN giving contrast in EBIC are charged and surrounded by a space charge region, as evidenced by the observed dependence of dislocation recombination strength on dopant concentration. For moderate (below ˜108 cm-2) dislocation densities, these defects do not primarily determine the average diffusion length of nonequilibrium charge carriers, although locally, dislocations are efficient recombination sites. In general, it is observed that the effect of the growth method [standard metalorganic chemical vapor deposition (MOCVD), epitaxial lateral overgrowth versions of MOCVD, and hydride vapor phase epitaxy] on the recombination activity of dislocations is not very pronounced, although the average diffusion lengths can widely differ for various samples. The glide of basal plane dislocations at room temperature promoted by low energy electron irradiation does not significantly change the recombination properties of dislocations.

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

Trishkina, L., E-mail: trishkina.53@mail.ru; Zboykova, N.; Koneva, N., E-mail: koneva@tsuab.ru

The aim of the investigation was the determination of the statistic description of dislocation distribution in each dislocation substructures component forming after different deformation degrees in the Cu-Al alloys. The dislocation structures were investigated by the transmission diffraction electron microscopy method. In the work the statistic description of distance distribution between the dislocations, dislocation barriers and dislocation tangles in the deformed Cu-Al alloys with different concentration of Al and test temperature at the grain size of 100 µm was carried out. It was established that the above parameters influence the dislocation distribution in different types of the dislocation substructures (DSS): dislocationmore » chaos, dislocation networks without disorientation, nondisoriented and disoriented cells, in the walls and inside the cells. The distributions of the distances between dislocations in the investigated alloys for each DSS type formed at certain deformation degrees and various test temperatures were plotted.« less

Modeling and 2-D discrete simulation of dislocation dynamics for plastic deformation of metal

NASA Astrophysics Data System (ADS)

Liu, Juan; Cui, Zhenshan; Ou, Hengan; Ruan, Liqun

2013-05-01

Two methods are employed in this paper to investigate the dislocation evolution during plastic deformation of metal. One method is dislocation dynamic simulation of two-dimensional discrete dislocation dynamics (2D-DDD), and the other is dislocation dynamics modeling by means of nonlinear analysis. As screw dislocation is prone to disappear by cross-slip, only edge dislocation is taken into account in simulation. First, an approach of 2D-DDD is used to graphically simulate and exhibit the collective motion of a large number of discrete dislocations. In the beginning, initial grains are generated in the simulation cells according to the mechanism of grain growth and the initial dislocation is randomly distributed in grains and relaxed under the internal stress. During the simulation process, the externally imposed stress, the long range stress contribution of all dislocations and the short range stress caused by the grain boundaries are calculated. Under the action of these forces, dislocations begin to glide, climb, multiply, annihilate and react with each other. Besides, thermal activation process is included. Through the simulation, the distribution of dislocation and the stress-strain curves can be obtained. On the other hand, based on the classic dislocation theory, the variation of the dislocation density with time is described by nonlinear differential equations. Finite difference method (FDM) is used to solve the built differential equations. The dislocation evolution at a constant strain rate is taken as an example to verify the rationality of the model.

Autonomic responses to ultrasound-guided percutaneous needle electrolysis of the patellar tendon in healthy male footballers.

PubMed

de la Cruz Torres, Blanca; Albornoz Cabello, Manuel; García Bermejo, Paula; Naranjo Orellana, José

2016-08-01

Ultrasound (US)-guided percutaneous needle electrolysis (PNE) is a novel minimally invasive approach, which involves the application of a galvanic current via an acupuncture needle. As in any procedure involving needling, vagal reactions have been reported during PNE. To examine for changes in autonomic activity during the US-guided PNE technique on healthy patellar tendons by measurement and analysis of heart rate variability (HRV). Twenty-two male footballers were randomly allocated to: a control group (11 players), for whom HRV was recorded for 10 min, both at rest and during an exhaustive US examination of the patellar tendon and adjacent structures; and an experimental group (11 players), for whom HRV was recorded for 10 min, both at rest and during application of US-guided PNE on the patellar tendon. The following HRV parameters were assessed: mean NN interval, mean heart rate, time domain parameters (SDNN, rMSSD, pNN50), diameters of the Poincaré plot (SD1, SD2), stress score, and sympathetic/parasympathetic ratio. There were no differences between groups in any baseline measurements, nor were there any significant differences between control group measurements (baseline vs intervention). The experimental group exhibited statistically significant increases in SDNN/SD1 (p=0.02/p=0.03) and SD2 (p=0.03), indicating increased parasympathetic and decreased sympathetic activity, respectively. US-guided PNE was associated with an autonomic imbalance characterised by greater parasympathetic activity, which could potentially result in a vasovagal reaction. Care should be taken to monitor for adverse reactions during US-guided PNE and simple HRV indicators may have a role in early detection. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Patellar tendon properties distinguish elite from non-elite soccer players and are related to peak horizontal but not vertical power.

PubMed

Murtagh, Conall F; Stubbs, Michael; Vanrenterghem, Jos; O'Boyle, Andrew; Morgans, Ryland; Drust, Barry; Erskine, Robert M

2018-06-02

To investigate potential differences in patellar tendon properties between elite and non-elite soccer players, and to establish whether tendon properties were related to power assessed during unilateral jumps performed in different directions. Elite (n = 16; age 18.1 ± 1.0 years) and non-elite (n = 13; age 22.3 ± 2.7 years) soccer players performed vertical, horizontal-forward and medial unilateral countermovement jumps (CMJs) on a force plate. Patellar tendon (PT) cross-sectional area, elongation, strain, stiffness, and Young's modulus (measured at the highest common force interval) were assessed with ultrasonography and isokinetic dynamometry. Elite demonstrated greater PT elongation (6.83 ± 1.87 vs. 4.92 ± 1.88 mm, P = 0.011) and strain (11.73 ± 3.25 vs. 8.38 ± 3.06%, P = 0.009) than non-elite soccer players. Projectile range and peak horizontal power during horizontal-forward CMJ correlated positively with tendon elongation (r = 0.657 and 0.693, P < 0.001) but inversely with Young's modulus (r = - 0.376 and - 0.402; P = 0.044 and 0.031). Peak medial power during medial CMJ correlated positively with tendon elongation (r = 0.658, P < 0.001) but inversely with tendon stiffness (r = - 0.368, P = 0.050). Not only does a more compliant patellar tendon appear to be an indicator of elite soccer playing status but it may also facilitate unilateral horizontal-forward and medial, but not vertical CMJ performance. These findings should be considered when prescribing talent selection and development protocols related to direction-specific power in elite soccer players.

MID-VASTUS VS MEDIAL PARA-PATELLAR APPROACH IN TOTAL KNEE REPLACEMENT—TIME TO DISCHARGE

PubMed Central

Mukherjee, P.; Press, J.; Hockings, M.

2009-01-01

Background It has been shown before that when compared with the medial para-patellar approach, the mid-vastus approach for TKR results in less post-operative pain for patients and more rapid recovery of straight leg raise. As far as we are aware the post-operative length of stay of the two groups of patients has not been compared. We postulated that the reduced pain and more rapid recovery of straight leg raise would translate into an earlier, safe, discharge home for the mid-vastus patients compared with those who underwent a traditional medial para-patellar approach. Methods Twenty patients operated on by each of five established knee arthroplasty surgeons were evaluated prospectively with regard to their pre and post-operative range of movement, time to achieve straight leg raise post-operatively and length of post-operative hospital stay. Only one of the surgeons performed the mid-vastus approach, and the measurements were recorded by physiotherapists who were blinded as to the approach used on each patient. Results The results were analysed using a standard statistical software package, and although the mean length of stay was lower for the mid-vastus patients, the difference did not reach a level of significance (p = 0.13). The time taken to achieve straight leg raise post-operatively was significantly less in the mid-vastus group (p<0.001). Conclusion Although this study confirms previous findings that the mid-vastus approach reduces the time taken for patients to achieve straight leg raise, when compared with the medial para-patellar approach, on its own it does not translate into a significantly shorter length of hospital stay. In order to reduce the length of post-operative hospital stay with an accelerated rehabilitation program for TKR, a multi-disciplinary approach is required. Patient expectations, GP support, physiotherapists and nursing staff all have a role to play and the mid-vastus approach, in permitting earlier straight leg raising, significantly contributes to this. PMID:19742080

Measuring the effect of femoral malrotation on knee joint biomechanics for total knee arthroplasty using computational simulation

PubMed Central

Kang, K-T.; Koh, Y-G.; Son, J.; Kwon, O-R.; Baek, C.; Jung, S. H.

2016-01-01

Objectives Malrotation of the femoral component can result in post-operative complications in total knee arthroplasty (TKA), including patellar maltracking. Therefore, we used computational simulation to investigate the influence of femoral malrotation on contact stresses on the polyethylene (PE) insert and on the patellar button as well as on the forces on the collateral ligaments. Materials and Methods Validated finite element (FE) models, for internal and external malrotations from 0° to 10° with regard to the neutral position, were developed to evaluate the effect of malrotation on the femoral component in TKA. Femoral malrotation in TKA on the knee joint was simulated in walking stance-phase gait and squat loading conditions. Results Contact stress on the medial side of the PE insert increased with internal femoral malrotation and decreased with external femoral malrotation in both stance-phase gait and squat loading conditions. There was an opposite trend in the lateral side of the PE insert case. Contact stress on the patellar button increased with internal femoral malrotation and decreased with external femoral malrotation in both stance-phase gait and squat loading conditions. In particular, contact stress on the patellar button increased by 98% with internal malrotation of 10° in the squat loading condition. The force on the medial collateral ligament (MCL) and the lateral collateral ligament (LCL) increased with internal and external femoral malrotations, respectively. Conclusions These findings provide support for orthopaedic surgeons to determine a more accurate femoral component alignment in order to reduce post-operative PE problems. Cite this article: K-T. Kang, Y-G. Koh, J. Son, O-R. Kwon, C. Baek, S. H. Jung, K. K. Park. Measuring the effect of femoral malrotation on knee joint biomechanics for total knee arthroplasty using computational simulation. Bone Joint Res 2016;5:552–559. DOI: 10.1302/2046-3758.511.BJR-2016-0107.R1. PMID:28094763

Patella morphological alteration after patella instability in growing rabbits.

PubMed

Niu, Jinghui; Qi, Qi; Niu, Yingzhen; Dong, Conglei; Dong, Zhenyue; Cui, Peng; Wang, Fei

2017-07-11

The shape of the patella has been considered to be a predisposing factor resulting in patellar instability, but the effects of abnormal patella position during its development are unclear. The present study evaluated patellar morphological changes after patella instability and evaluated the influence of patellar instability on the patella shape. Twenty rabbits that were 2 months old were included in the study. The left knee of each rabbit, defined as the experimental group (N = 20 knees/group), underwent a medial soft tissue restraint release. The right knee of each rabbit, defined as the control group (N = 20 knees/group), did not undergo any surgical procedures. A CT scan was performed on each knee before surgery and 6 months post-surgery to measure the transverse diameter, thickness, Wiberg index, and Wiberg angle for analysis of the patellar morphological changes. Cross-specimen examination was conducted to evaluate the differences between the experimental group and the control group. The four indices remained the same between the two groups before surgery. However, 6 months after surgery, the mean transverse diameter of the patellae in the experimental group was significantly longer than that in the control group (P < 0.001), while the mean thickness in the experimental group was not significantly greater than that in the control group (P = 0.314), resulting in a flattened shape. The Wiberg indices were not significantly different between the two groups. However, the mean Wiberg angle was higher in the experimental group than in the control group (P < 0.001), which resulted in a flattened articular surface of the patella. The sectional shape and articular surface of the patella became more flattened after patella instability in this study, which indicates that patella dysplasia could be caused by patella instability. Clinically, early intervention for adolescent patients with patella instability is important.

Tibial Inlay Press-fit Fixation Versus Interference Screw in Posterior Cruciate Ligament Reconstruction.

PubMed

Ettinger, Max; Büermann, Sarah; Calliess, Tilman; Omar, Mohamed; Krettek, Christian; Hurschler, Christof; Jagodzinski, Michael; Petri, Maximilian

2013-01-01

Reconstruction of the posterior cruciate ligament (PCL) by a tibial press-fit fixation of the patellar tendon with an accessory bone plug is a promising approach because no foreign materials are required. Until today, there is no data about the biomechanical properties of such press-fit fixations. The aim of this study was to compare the biomechanical qualities of a bone plug tibial inlay technique with the commonly applied interference screw of patellar tendon PCL grafts. Twenty patellar tendons including a bone block were harvested from ten human cadavers. The grafts were implanted into twenty legs of adult German country pigs. In group P, the grafts were attached in a press-fit technique with accessory bone plug. In group S, the grafts were fixed with an interference screw. Each group consisted of 10 specimens. The constructs were biomechanically analyzed in cyclic loading between 60 and 250 N for 500 cycles recording elongation. Finally, ultimate failure load and failure mode were analyzed. Ultimate failure load was 598.6±36.3 N in group P and 653.7±39.8 N in group S (not significant, P>0.05). Elongation during cyclic loading between the 1(st) and the 20(th) cycle was 3.4±0.9 mm for group P and 3.1±1 mm for group S. Between the 20(th) and the 500(th) cycle, elongation was 4.2±2.3 mm in group P and 2.5±0.9 mm in group S (not significant, P>0.05). This is the first study investigating the biomechanical properties of tibial press-fit fixation of the patellar tendon with accessory bone plug in posterior cruciate ligament reconstruction. The implant-free tibial inlay technique shows equal biomechanical characteristics compared to an interference screw fixation. Further in vivo studies are desirable to compare the biological behavior and clinical relevance of this fixation device.

Changes in Indirect Markers of Muscle Damage and Tendons After Daily Drop Jumping Exercise with Rapid Load Increase

PubMed Central

Paleckis, Vidas; Mickevičius, Mantas; Snieckus, Audrius; Streckis, Vytautas; Pääsuke, Mati; Rutkauskas, Saulius; Steponavičiūtė, Rasa; Skurvydas, Albertas; Kamandulis, Sigitas

2015-01-01

The aim of this study was to assess changes in indirect markers of muscle damage and type I collagen degradation, as well as, patellar and Achilles tendon morphological differences during nine daily drop-jumps sessions with constant load alternated with rapid increases in load to test the hypothesis that frequent drop-jump training results in negative muscular and tendon adaptation. Young men (n = 9) performed daily drop jump workouts with progression every 3 days in terms of number of jumps, platform height and squat amplitude. Voluntary and electrically evoked knee extensor torque, muscle soreness, blood plasma creatine kinase (CK) activity and carboxyterminal cross-linked telopeptide (ICTP), patellar and Achilles tendon thickness and cross-sectional area (CSA) were assessed at different time points during the training period and again on days 1, 3, 10 and 17 after the training. The findings were as follows: (1) steady decline in maximal muscle strength with major recovery within 24 hours after the first six daily training sessions; (2) larger decline in electrically induced muscle torque and prolonged recovery during last three training sessions; (3) increase in patellar and Achilles tendons CSA without change in thickness towards the end of training period; (4) increase in jump height but not in muscle strength after whole training period. Our findings suggest that frequent drop-jump sessions with constant load alternated with rapid increases in load do not induce severe muscle damage or major changes in tendons, nonetheless, this type of loading is not advisable for muscle strength improvement. Key points Frequent drop jump training induces activation mode dependent muscle torque depression late in the training period. No significant changes in the thickness of patellar and Achilles tendons are observed during frequent training, while CSA increases towards the end of training period. Longitudinal effect for jump height but not for muscle strength is evident after the whole training period. PMID:26664280

Is the effectiveness of patellofemoral bracing modified by patellofemoral alignment and trochlear morphology?

PubMed

Zhang, Xi; Eyles, Jillian P; Makovey, Joanna; Williams, Matthew J; Hunter, David J

2017-04-21

This study was performed to determine if the effectiveness of patellofemoral bracing as a treatment for patellofemoral osteoarthritis is influenced by patellofemoral joint alignment and trochlear morphology. We hypothesized that those with more extreme patellar malalignment would benefit more from bracing. Thirty-eight patients who had received bracing as part of a comprehensive treatment plan for patellofemoral osteoarthritis were selected for this study. Ten measures of patellar alignment were taken from X-rays. These alignment measures were divided into percentile groups (tertiles) for contingency table analysis. Treatment outcome was measured by Western Ontario and Macmasters Universities Osteoarthritis Index (WOMAC) scores and these were dichotomised into two groups according to "Improved" or "Not Improved" according to the minimum clinically important difference (MCID). Spearman's rho test was performed for continuous variables and Fisher's exact test was performed for correlation between tertile groups and MCID categories. Thirty-eight patients (9 male and 29 female) between the ages of 51 to 89 were included in this study. WOMAC scores ranged from -25 to 41.67, with a mean change of -3.97, 31.6, 44.7 and 31.6% of patients falling into the "Improved" group for Global, Pain and Function scores respectively. We found a non-significant trend shown (p = 0.058, correlation coefficient 0.31) between bisect offset and change in WOMAC global, indicating a trend for higher change in WOMAC scores with increasing bisect offset. Statistically significant correlations were found between mean MCID categories for the WOMAC global and function groups when analysed against percentile groups for bisect offset (p < 0.01) and patellar subluxation distance (p < 0.05), indicating those in higher percentile groups were more likely not to improve after six months. Higher bisect offset and patellar subluxation distance measures were associated with poorer outcomes. However, due to the limited sample size, more studies are required to fully examine this relationship.

Results of Lateral Retinacular Release Plus Circumpatellar Electrocautery in Total Knee Arthroplasty without Patellar Resurfacing.

PubMed

Wang, Yong; Sun, Jun-Ying; Zha, Guo-Chun

2017-03-01

Anterior knee pain (AKP) is integral to the overall success of total knee arthroplasty (TKA) without patellar resurfacing. Numerous studies have evaluated various factors that may contribute to AKP, including patellofemoral design, surgical technique, characteristics of the patient, and degree of chondromalacia. This study aims to explore whether patients who received lateral retinacular release (LRR) plus circumpatellar electrocautery (CE) in TKA attain a low incidence of AKP and whether the LRR plus CE increases postoperative complications. Between February 2001 and February 2009, all patients undergoing TKA without patellar resurfacing and LRR plus CE were evaluated. In total, 286 TKAs in 259 (88.7%) patients were available for assessment, with a mean of 9.3 ± 2.5 years (range: 6-14 years) after the index TKA. The patients were evaluated with a VAS and the Kujala patellofemoral score (KPS) for AKP and the Knee Society's clinical scoring system (KSS) for the clinical function. Satisfaction and LRR-related complications were also assessed. The mean KPS and KSS improved from 45.2 ± 12.9 and 75.4 ± 26.8 points preoperatively to 82.8 ± 10.0 and 151.6 ± 17.3 points at the final follow-up ( p  < 0.001), respectively. Subjectively, 5.6% (16 of 286) of patients suffered from AKP and 88.1% (252 of 286) were satisfied or very satisfied. Postoperative complications occurred in 15 (5.2%) patients, but these complications were mild and did not require reoperation. None of patients exhibited aseptic and septic prosthesis loosening and required revision surgery in the final follow-up. LRR plus CE appears to be a reasonable option in TKA without patellar resurfacing. It may achieve adequate mid-term results, with a low incidence of AKP and postoperative complications.The level of evidence of the study is therapeutic level IV. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Regional strain variations in the human patellar tendon.

PubMed

Pearson, Stephen J; Ritchings, Tim; Mohamed, Azlan S A

2014-07-01

Characteristics of localized tendon strain in vivo are largely unknown. The present study examines local tendon strain between the deep, middle, and surface structures at the proximal and distal aspects of the patellar tendon during ramped isometric contractions. Male subjects (age 28.0 ± 6.3 yr) were examined for patellar tendon excursion (anterior, midsection, and posterior) during ramped isometric voluntary contractions using real-time B-mode ultrasonography and dynamometry. Regional tendon excursion measurements were compared using an automated pixel tracking method. Strain was determined from the tendon delta length normalized to initial/resting segment length. Strain increased from 10% to 100% of force for all regions. Significantly greater mean strain was seen for the anterior proximal region compared to the posterior and mid layer of the tendon (7.5% ± 1.1% vs 3.7% ± 0.5% vs 5.5% ± 1.0%; P < 0.05). Similarly, the distal posterior region showed greater mean strain compared to the mid and anterior regions (7.9% ± 0.6% vs 5.0% ± 0.6% vs 5.4% ± 0.6%; P < 0.05). Relative changes in strain differences from 50% to 100% of force for the proximal region were greatest for the anterior to midline regions (4.6% ± 0.6% and 5.6% ± 0.6%, respectively) and those for the distal region were also greatest for the anterior to midline regions (4.4% ± 0.2% and 5.3% ± 0.2%, respectively). The largest mean strain for the proximal region was at the anterior layer (7.5% ± 1.1%) and that for the distal tendon region was at the posterior layer (7.9% ± 0.9%). This study shows significant regional differences in strain during ramped isometric contractions for the patellar tendon. Lower proximal strains in the posterior tendon compared to the anterior region may be associated with the suggestion of "stress shielding" as an etiological factor in insertional tendinopathy.

Synergistic promoting effects of bone morphogenetic protein 12/connective tissue growth factor on functional differentiation of tendon derived stem cells and patellar tendon window defect regeneration.

PubMed

Xu, Kang; Sun, Yanjun; Kh Al-Ani, Mohanad; Wang, Chunli; Sha, Yongqiang; Sung, Kl Paul; Dong, Nianguo; Qiu, Xuefeng; Yang, Li

2018-01-03

Current study investigated bone morphogenetic protein 12 (BMP12) and connective tissue growth factor (CTGF) activate tendon derived stem cells (TDSCs) tenogenic differentiation, and promotion of injured tendon regeneration. TDSCs were transfected with BMP12 and CTGF via recombinant adenovirus (Ad) infection. Gene transfection efficiency, cell viability and cytotoxicity, tenogenic gene expression, collagen I/III synthesis were evaluated in vitro. For the in vivo study, the transfected cells were transplanted into the rat patellar tendon window defect. At weeks 2 and 8 of post-surgery, the repaired tendon tissues were harvested for histological and biomechanical examinations. The transfected TDSCs revealed relatively stable transfection efficiency (80-90%) with active cell viability means while rare cytotoxicity in each group. During days 1 and 5, BMP12 and CTGF transfection caused tenogenic differentiation genes activation in TDSCs: type I/III collagen, tenascin-C, and scleraxis were all up-regulated, whereas osteogenic, adipogenic, and chondrogenic markers were all down-regulated respectively. In addition, BMP12 and CTGF overexpression significantly promote type I/III collagen synthesis. After in vivo transplantation, at 2 and 8 weeks post-surgery, BMP12, CTGF and co-transfection groups showed more integrated tendon tissue structure versus control, meanwhile, the ultimate failure loads and Young's were all higher than control. Remarkably, at 8 weeks post-surgery, the biomechanical properties of co-transfection group was approaching to normal rat patellar tendon, moreover, the ratio of type III/I collagen maintained about 20% in each transfection group, meanwhile, the type I collagen were significantly increased with co-transfection treatment. In conclusion, BMP12 and CTGF transfection stimulate tenogenic differentiation of TDSCs. The synergistic effects of simultaneous transfection of both may significantly promoted rat patellar tendon window defect regeneration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tendinous tissue properties after short- and long-term functional overload: Differences between controls, 12 weeks and 4 years of resistance training.

PubMed

Massey, G J; Balshaw, T G; Maden-Wilkinson, T M; Folland, J P

2018-04-01

The potential for tendinous tissues to adapt to functional overload, especially after several years of exposure to heavy-resistance training, is largely unexplored. This study compared the morphological and mechanical characteristics of the patellar tendon and knee extensor tendon-aponeurosis complex between young men exposed to long-term (4 years; n = 16), short-term (12 weeks; n = 15) and no (untrained controls; n = 39) functional overload in the form of heavy-resistance training. Patellar tendon cross-sectional area, vastus lateralis aponeurosis area and quadriceps femoris volume, plus patellar tendon stiffness and Young's modulus, and tendon-aponeurosis complex stiffness, were quantified with MRI, dynamometry and ultrasonography. As expected, long-term trained had greater muscle strength and volume (+58% and +56% vs untrained, both P < .001), as well as a greater aponeurosis area (+17% vs untrained, P < .01), but tendon cross-sectional area (mean and regional) was not different between groups. Only long-term trained had reduced patellar tendon elongation/strain over the whole force/stress range, whilst both short-term and long-term overload groups had similarly greater stiffness/Young's modulus at high force/stress (short-term +25/22%, and long-term +17/23% vs untrained; all P < .05). Tendon-aponeurosis complex stiffness was not different between groups (ANOVA, P = .149). Despite large differences in muscle strength and size, years of resistance training did not induce tendon hypertrophy. Both short-term and long-term overload demonstrated similar increases in high-force mechanical and material stiffness, but reduced elongation/strain over the whole force/stress range occurred only after years of overload, indicating a force/strain specific time-course to these adaptations. © 2017 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Modal analysis of dislocation vibration and reaction attempt frequency

DOE PAGES

Sobie, Cameron; Capolungo, Laurent; McDowell, David L.; ...

2017-02-04

Transition state theory is a fundamental approach for temporal coarse-graining. It estimates the reaction rate for a transition processes by quantifying the activation free energy and attempt frequency for the unit process. To calculate the transition rate of a gliding dislocation, the attempt frequency is often obtained from line tension estimates of dislocation vibrations, a highly simplified model of dislocation behavior. This work revisits the calculation of attempt frequency for a dislocation bypassing an obstacle, in this case a self-interstitial atom (SIA) loop. First, a direct calculation of the vibrational characteristics of a finite pinned dislocation segment is compared tomore » line tension estimates before moving to the more complex case of dislocation-obstacle bypass. The entropic factor associated with the attempt frequency is calculated for a finite dislocation segment and for an infinite glide dislocation interacting with an SIA loop. Lastly, it is found to be dislocation length independent for three cases of dislocation-self interstitial atom (SIA) loop interactions.« less

Dynamics of threading dislocations in porous heteroepitaxial GaN films

NASA Astrophysics Data System (ADS)

Gutkin, M. Yu.; Rzhavtsev, E. A.

2017-12-01

Behavior of threading dislocations in porous heteroepitaxial gallium nitride (GaN) films has been studied using computer simulation by the two-dimensional discrete dislocation dynamics approach. A computational scheme, where pores are modeled as cross sections of cylindrical cavities, elastically interacting with unidirectional parallel edge dislocations, which imitate threading dislocations, is used. Time dependences of coordinates and velocities of each dislocation from dislocation ensembles under investigation are obtained. Visualization of current structure of dislocation ensemble is performed in the form of a location map of dislocations at any time. It has been shown that the density of appearing dislocation structures significantly depends on the ratio of area of a pore cross section to area of the simulation region. In particular, increasing the portion of pores surface on the layer surface up to 2% should lead to about a 1.5-times decrease of the final density of threading dislocations, and increase of this portion up to 15% should lead to approximately a 4.5-times decrease of it.

The infrapatellar fat pad is a dynamic and mobile structure, which deforms during knee motion, and has proximal extensions which wrap around the patella.

PubMed

Stephen, Joanna M; Sopher, Ran; Tullie, Sebastian; Amis, Andrew A; Ball, Simon; Williams, Andy

2018-04-20

The infrapatellar fat pad (IFP) is a common cause of knee pain and loss of knee flexion and extension. However, its anatomy and behavior are not consistently defined. Thirty-six unpaired fresh frozen knees (median age 34 years, range 21-68) were dissected, and IFP attachments and volume measured. The rectus femoris was elevated, suprapatellar pouch opened and videos recorded looking inferiorly along the femoral shaft at the IFP as the knee was flexed. The patellar retinacula were incised and the patella reflected distally. The attachment of the ligamentum mucosum (LMuc) to the intercondylar notch was released from the anterior cruciate ligament (ACL), both menisci and to the tibia via meniscotibial ligaments. IFP strands projecting along both sides of the patella were elevated and the IFP dissected from the inferior patellar pole. Magnetic resonance imaging (MRI) of one knee at ten flexion angles was performed and the IFP, patella, tibia and femur segmented. In all specimens the IFP attached to the inferior patellar pole, femoral intercondylar notch (via the LMuc), proximal patellar tendon, intermeniscal ligament, both menisci and the anterior tibia via the meniscotibial ligaments. In 30 specimens the IFP attached to the anterior ACL fibers via the LMuc, and in 29 specimens it attached directly to the central anterior tibia. Proximal IFP extensions were identified alongside the patella in all specimens and visible on MRI [medially (100% of specimens), mean length 56.2 ± 8.9 mm, laterally (83%), mean length 23.9 ± 6.2 mm]. Mean IFP volume was 29.2 ± 6.1 ml. The LMuc, attached near the base of the middle IFP lobe, acting as a 'tether' drawing it superiorly during knee extension. The medial lobe consistently had a pedicle superomedially, positioned between the patella and medial trochlea. MRI scans demonstrated how the space between the anterior tibia and patellar tendon ('the anterior interval') narrowed during knee flexion, displacing the IFP superiorly and posteriorly as it conformed to the trochlear and intercondylar notch surfaces. Proximal IFP extensions are a novel description. The IFP is a dynamic structure, displacing significantly during knee motion, which is, therefore, vulnerable to interference from trauma or repetitive overload. Given that this trauma is often surgical, it may be appropriate that surgeons learn to minimize injury to the fat pad at surgery.

Effect of Medial Patellofemoral Ligament Reconstruction Method on Patellofemoral Contact Pressures and Kinematics.

PubMed

Stephen, Joanna M; Kittl, Christoph; Williams, Andy; Zaffagnini, Stefano; Marcheggiani Muccioli, Giulio Maria; Fink, Christian; Amis, Andrew A

2016-05-01

There remains a lack of evidence regarding the optimal method when reconstructing the medial patellofemoral ligament (MPFL) and whether some graft constructs can be more forgiving to surgical errors, such as overtensioning or tunnel malpositioning, than others. The null hypothesis was that there would not be a significant difference between reconstruction methods (eg, graft type and fixation) in the adverse biomechanical effects (eg, patellar maltracking or elevated articular contact pressure) resulting from surgical errors such as tunnel malpositioning or graft overtensioning. Controlled laboratory study. Nine fresh-frozen cadaveric knees were placed on a customized testing rig, where the femur was fixed but the tibia could be moved freely from 0° to 90° of flexion. Individual quadriceps heads and the iliotibial tract were separated and loaded to 205 N of tension using a weighted pulley system. Patellofemoral contact pressures and patellar tracking were measured at 0°, 10°, 20°, 30°, 60°, and 90° of flexion using pressure-sensitive film inserted between the patella and trochlea, in conjunction with an optical tracking system. The MPFL was transected and then reconstructed in a randomized order using a (1) double-strand gracilis tendon, (2) quadriceps tendon, and (3) tensor fasciae latae allograft. Pressure maps and tracking measurements were recorded for each reconstruction method in 2 N and 10 N of tension and with the graft positioned in the anatomic, proximal, and distal femoral tunnel positions. Statistical analysis was undertaken using repeated-measures analyses of variance, Bonferroni post hoc analyses, and paired t tests. Anatomically placed grafts during MPFL reconstruction tensioned to 2 N resulted in the restoration of intact medial joint contact pressures and patellar tracking for all 3 graft types investigated (P > .050). However, femoral tunnels positioned proximal or distal to the anatomic origin resulted in significant increases in the mean medial joint contact pressure, medial patellar tilt, and medial patellar translation during knee flexion or extension, respectively (P < .050), regardless of graft type, as did tensioning to 10 N. The importance of the surgical technique, specifically correct femoral tunnel positioning and graft tensioning, in restoring normal patellofemoral joint (PFJ) kinematics and articular cartilage contact stresses is evident, and the type of MPFL graft appeared less important. The correct femoral tunnel position and graft tension for restoring normal PFJ kinematics and articular cartilage contact stresses appear to be more important than graft selection during MPFL reconstruction. These findings emphasize the importance of the surgical technique when undertaking this procedure. © 2016 The Author(s).

Novel Augmentation Technique for Patellar Tendon Repair Improves Strength and Decreases Gap Formation: A Cadaveric Study.

PubMed

Black, James C; Ricci, William M; Gardner, Michael J; McAndrew, Christopher M; Agarwalla, Avinesh; Wojahn, Robert D; Abar, Orchid; Tang, Simon Y

2016-12-01

Patellar tendon ruptures commonly are repaired using transosseous patellar drill tunnels with modified-Krackow sutures in the patellar tendon. This simple suture technique has been associated with failure rates and poor clinical outcomes in a modest proportion of patients. Failure of this repair technique can result from gap formation during loading or a single catastrophic event. Several augmentation techniques have been described to improve the integrity of the repair, but standardized biomechanical evaluation of repair strength among different techniques is lacking. The purpose of this study was to describe a novel figure-of-eight suture technique to augment traditional fixation and evaluate its biomechanical performance. We hypothesized that the augmentation technique would (1) reduce gap formation during cyclic loading and (2) increase the maximum load to failure. Ten pairs (two male, eight female) of fresh-frozen cadaveric knees free of overt disorders or patellar tendon damage were used (average donor age, 76 years; range, 65-87 years). For each pair, one specimen underwent the standard transosseous tunnel suture repair with a modified-Krackow suture technique and the second underwent the standard repair with our experimental augmentation method. Nine pairs were suitable for testing. Each specimen underwent cyclic loading while continuously measuring gap formation across the repair. At the completion of cyclic loading, load to failure testing was performed. A difference in gap formation and mean load to failure was seen in favor of the augmentation technique. At 250 cycles, a 68% increase in gap formation was seen for the control group (control: 5.96 ± 0.86 mm [95% CI, 5.30-6.62 mm]; augmentation: 3.55 ± 0.56 mm [95% CI, 3.12-3.98 mm]; p = 0.02). The mean load to failure was 13% greater in the augmentation group (control: 899.57 ± 96.94 N [95% CI, 825.06-974.09 N]; augmentation: 1030.70 ± 122.41 N [95% CI, 936.61-1124.79 N]; p = 0.01). This biomechanical study showed improved performance of a novel augmentation technique compared with the standard repair, in terms of reduced gap formation during cyclic loading and increased maximum load to failure. Decreased gap formation and higher load to failure may improve healing potential and minimize failure risk. This study shows a potential biomechanical advantage of the augmentation technique, providing support for future clinical investigations comparing this technique with other repair methods that are in common use such as transosseous suture repair.

Density of bunched threading dislocations in epitaxial GaN layers as determined using X-ray diffraction

NASA Astrophysics Data System (ADS)

Barchuk, M.; Holý, V.; Rafaja, D.

2018-04-01

X-ray diffraction is one of the most popular experimental methods employed for determination of dislocation densities, as it can recognize both the strain fields and the local lattice rotations produced by dislocations. The main challenge of the quantitative analysis of the dislocation density is the formulation of a suitable microstructure model, which describes the dislocation arrangement and the effect of the interactions between the strain fields from neighboring dislocations reliably in order to be able to determine the dislocation densities precisely. The aim of this study is to prove the capability of X-ray diffraction and two computational methods, which are frequently used for quantification of the threading dislocation densities from X-ray diffraction measurements, in the special case of partially bunched threading dislocations. The first method is based on the analysis of the dislocation-controlled crystal mosaicity, and the other one on the analysis of diffuse X-ray scattering from threading dislocations. The complementarity of both methods is discussed. Furthermore, it is shown how the complementarity of these methods can be used to improve the results of the quantitative analysis of bunched and thus inhomogeneously distributed threading dislocations and to get a better insight into the dislocation arrangement.

Interaction of 〈1 0 0〉 dislocation loops with dislocations studied by dislocation dynamics in α-iron

NASA Astrophysics Data System (ADS)

Shi, X. J.; Dupuy, L.; Devincre, B.; Terentyev, D.; Vincent, L.

2015-05-01

Interstitial dislocation loops with Burgers vector of 〈1 0 0〉 type are formed in α-iron under neutron or heavy ion irradiation. As the density and size of these loops increase with radiation dose and temperature, these defects are thought to play a key role in hardening and subsequent embrittlement of iron-based steels. The aim of the present work is to study the pinning strength of the loops on mobile dislocations. Prior to run massive Dislocation Dynamics (DD) simulations involving experimentally representative array of radiation defects and dislocations, the DD code and its parameterization are validated by comparing the individual loop-dislocation reactions with those obtained from direct atomistic Molecular Dynamics (MD) simulations. Several loop-dislocation reaction mechanisms are successfully reproduced as well as the values of the unpinning stress to detach mobile dislocations from the defects.

Strength of Dislocation Junctions in FCC-monocrystals with a [\\overline{1}11] Deformation Axis

NASA Astrophysics Data System (ADS)

Kurinnaya, R. I.; Zgolich, M. V.; Starenchenko, V. A.

2017-07-01

The paper examines all dislocation reactions implemented in FCC-monocrystals with axis deformation oriented in the [\\overline{1}11] direction. It identifies the fracture stresses of dislocation junctions depending on intersection geometry of the reacting dislocation loop segments. Estimates are produced for the full spectrum of reacting forest dislocations. The paper presents the statistical data of the research performed and identifies the share of long strong dislocation junctions capable of limiting the zone of dislocation shift.

Tailoring Superconductivity with Quantum Dislocations.

PubMed

Li, Mingda; Song, Qichen; Liu, Te-Huan; Meroueh, Laureen; Mahan, Gerald D; Dresselhaus, Mildred S; Chen, Gang

2017-08-09

Despite the established knowledge that crystal dislocations can affect a material's superconducting properties, the exact mechanism of the electron-dislocation interaction in a dislocated superconductor has long been missing. Being a type of defect, dislocations are expected to decrease a material's superconducting transition temperature (T c ) by breaking the coherence. Yet experimentally, even in isotropic type I superconductors, dislocations can either decrease, increase, or have little influence on T c . These experimental findings have yet to be understood. Although the anisotropic pairing in dirty superconductors has explained impurity-induced T c reduction, no quantitative agreement has been reached in the case a dislocation given its complexity. In this study, by generalizing the one-dimensional quantized dislocation field to three dimensions, we reveal that there are indeed two distinct types of electron-dislocation interactions. Besides the usual electron-dislocation potential scattering, there is another interaction driving an effective attraction between electrons that is caused by dislons, which are quantized modes of a dislocation. The role of dislocations to superconductivity is thus clarified as the competition between the classical and quantum effects, showing excellent agreement with existing experimental data. In particular, the existence of both classical and quantum effects provides a plausible explanation for the illusive origin of dislocation-induced superconductivity in semiconducting PbS/PbTe superlattice nanostructures. A quantitative criterion has been derived, in which a dislocated superconductor with low elastic moduli and small electron effective mass and in a confined environment is inclined to enhance T c . This provides a new pathway for engineering a material's superconducting properties by using dislocations as an additional degree of freedom.

On damping of screw dislocation bending vibrations in dissipative crystal: limiting cases

NASA Astrophysics Data System (ADS)

Dezhin, V. V.

2018-03-01

The expression for the generalized susceptibility of the dislocation obtained earlier was used. The electronic drag mechanism of dislocations is considered. The study of small dislocation oscillations was limited. The contribution of the attenuation of low-frequency bending screw dislocation vibrations to the overall coefficient of dynamic dislocation drag in the long-wave and short-wave limits is calculated. The damping of short-wave bending screw dislocation vibrations caused by an external action of an arbitrary frequency has been investigated. The contribution of long-wave bending screw dislocation vibrations damping in the total drag coefficient at an arbitrary frequency is found.

Automated identification and indexing of dislocations in crystal interfaces

DOE PAGES

Stukowski, Alexander; Bulatov, Vasily V.; Arsenlis, Athanasios

2012-10-31

Here, we present a computational method for identifying partial and interfacial dislocations in atomistic models of crystals with defects. Our automated algorithm is based on a discrete Burgers circuit integral over the elastic displacement field and is not limited to specific lattices or dislocation types. Dislocations in grain boundaries and other interfaces are identified by mapping atomic bonds from the dislocated interface to an ideal template configuration of the coherent interface to reveal incompatible displacements induced by dislocations and to determine their Burgers vectors. Additionally, the algorithm generates a continuous line representation of each dislocation segment in the crystal andmore » also identifies dislocation junctions.« less

The association of patellofemoral joint morphology with chondromalacia patella: a quantitative MRI analysis.

PubMed

Tuna, Burcu Kaya; Semiz-Oysu, Aslıhan; Pekar, Bilhan; Bukte, Yasar; Hayirlioglu, Alper

2014-01-01

The relationship of patellofemoral congruency with chondromalacia patellae (CP) was retrospectively evaluated. Lateral patellar tilt angle (LPTA), sulcus angle (SA), trochlear depth (TD), and patella angle (PA) were measured at 301 knee magnetic resonance images and compared between groups with and without CP. In the CP group, LPTA and TD were significantly low (P<.01), SA was high (P<.01), while PA showed no difference (P>.05). The parameters were also compared between groups with mild and severe CP, and no significant difference was found (P>.05). Our results demonstrate that patellar tilt and trochlear dysplasia are related to the presence but not the degree of CP. Copyright © 2014 Elsevier Inc. All rights reserved.

Dry Arthroscopy With a Retraction System for Matrix-Aided Cartilage Repair of Patellar Lesions

PubMed Central

Sadlik, Boguslaw; Wiewiorski, Martin

2014-01-01

Several commercially available cartilage repair techniques use a natural or synthetic matrix to aid cartilage regeneration (e.g., autologous matrix–induced chondrogenesis or matrix-induced cartilage implantation). However, the use of matrix-aided techniques during conventional knee joint arthroscopy under continuous irrigation is challenging. Insertion and fixation of the matrix can be complicated by the presence of fluid and the confined patellofemoral joint space with limited access to the lesion. To overcome these issues, we developed a novel arthroscopic approach for matrix-aided cartilage repair of patellar lesions. This technical note describes the use of dry arthroscopy assisted by a minimally invasive retraction system. An autologous matrix–induced chondrogenesis procedure is used to illustrate this novel approach. PMID:24749035

Misfit dislocation patterns of Mg-Nb interfaces

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

Chen, Youxing; Shao, Shuai; Liu, Xiang-Yang

The role of heterogeneous interfaces in improving mechanical properties of polycrystalline aggregates and laminated composites has been well recognized with interface structure being of fundamental importance in designing composites containing multiple interfaces. In this paper, taking the Mg (hexagonal close-packed (hcp))/Nb (body-centered cubic (bcc)) interface as an example, we develop Mg-Nb interatomic potentials for predicting atomic configurations of Mg/Nb interfaces. We systematically characterize interface dislocations of Mg/Nb interfaces with Nishiyama-Wassermann (NW) and Kurdjumov-Sachs (KS) orientation relationships and propose a generalized procedure of characterizing interface structure by combining atomistic simulation and interface dislocation theory, which is applicable for not only hcp/bccmore » interfaces, but also other systems with complicated interface dislocation configurations.Here, in Mg/Nb, interface dislocation networks of two types of interfaces are significantly different although they originate from partial dislocations of similar character: the NW interface is composed of three sets of partial dislocations, while the KS interface is composed of four sets of interface dislocations - three sets of partial dislocations and one set of full dislocations that forms from the reaction of two close partial dislocations.« less

Dislocation dynamics simulations of interactions between gliding dislocations and radiation induced prismatic loops in zirconium

NASA Astrophysics Data System (ADS)

Drouet, Julie; Dupuy, Laurent; Onimus, Fabien; Mompiou, Frédéric; Perusin, Simon; Ambard, Antoine

2014-06-01

The mechanical behavior of Pressurized Water Reactor fuel cladding tubes made of zirconium alloys is strongly affected by neutron irradiation due to the high density of radiation induced dislocation loops. In order to investigate the interaction mechanisms between gliding dislocations and loops in zirconium, a new nodal dislocation dynamics code, adapted to Hexagonal Close Packed metals, has been used. Various configurations have been systematically computed considering different glide planes, basal or prismatic, and different characters, edge or screw, for gliding dislocations with -type Burgers vectors. Simulations show various interaction mechanisms such as (i) absorption of a loop on an edge dislocation leading to the formation of a double super-jog, (ii) creation of a helical turn, on a screw dislocation, that acts as a strong pinning point or (iii) sweeping of a loop by a gliding dislocation. It is shown that the clearing of loops is more favorable when the dislocation glides in the basal plane than in the prismatic plane explaining the easy dislocation channeling in the basal plane observed after neutron irradiation by transmission electron microscopy.

Probing the character of ultra-fast dislocations

DOE PAGES

Rudd, R. E.; Ruestes, C. J.; Bringa, E. M.; ...

2015-11-23

Plasticity is often controlled by dislocation motion, which was first measured for low pressure, low strain rate conditions decades ago. However, many applications require knowledge of dislocation motion at high stress conditions where the data are sparse, and come from indirect measurements dominated by the effect of dislocation density rather than velocity. Here we make predictions based on atomistic simulations that form the basis for a new approach to measure dislocation velocities directly at extreme conditions using three steps: create prismatic dislocation loops in a near-surface region using nanoindentation, drive the dislocations with a shockwave, and use electron microscopy tomore » determine how far the dislocations moved and thus their velocity at extreme stress and strain rate conditions. We report on atomistic simulations of tantalum that make detailed predictions of dislocation flow, and find that the approach is feasible and can uncover an exciting range of phenomena, such as transonic dislocations and a novel form of loop stretching. Furthermore, the simulated configuration enables a new class of experiments to probe average dislocation velocity at very high applied shear stress.« less

Three-dimensional formulation of dislocation climb

NASA Astrophysics Data System (ADS)

Gu, Yejun; Xiang, Yang; Quek, Siu Sin; Srolovitz, David J.

2015-10-01

We derive a Green's function formulation for the climb of curved dislocations and multiple dislocations in three-dimensions. In this new dislocation climb formulation, the dislocation climb velocity is determined from the Peach-Koehler force on dislocations through vacancy diffusion in a non-local manner. The long-range contribution to the dislocation climb velocity is associated with vacancy diffusion rather than from the climb component of the well-known, long-range elastic effects captured in the Peach-Koehler force. Both long-range effects are important in determining the climb velocity of dislocations. Analytical and numerical examples show that the widely used local climb formula, based on straight infinite dislocations, is not generally applicable, except for a small set of special cases. We also present a numerical discretization method of this Green's function formulation appropriate for implementation in discrete dislocation dynamics (DDD) simulations. In DDD implementations, the long-range Peach-Koehler force is calculated as is commonly done, then a linear system is solved for the climb velocity using these forces. This is also done within the same order of computational cost as existing discrete dislocation dynamics methods.

Ultrasonic influence on evolution of disordered dislocation structures

NASA Astrophysics Data System (ADS)

Bachurin, D. V.; Murzaev, R. T.; Nazarov, A. A.

2017-12-01

Evolution of disordered dislocation structures under ultrasonic influence is studied in a model two-dimensional grain within the discrete-dislocation approach. Non-equilibrium grain boundary state is mimicked by a mesodefect located at the corners of the grain, stress field of which is described by that of a wedge junction disclination quadrupole. Significant rearrangement related to gliding of lattice dislocations towards the grain boundaries is found, which results in a noticeable reduction of internal stress fields and cancel of disclination quadrupole. The process of dislocation structure evolution passes through two stages: rapid and slow. The main dislocation rearrangement occurs during the first stage. Reduction of internal stress fields is associated with the number of dislocations entered into the grain boundaries. The change of misorientation angle due to lattice dislocations absorbed by the grain boundaries is evaluated. Amplitude of ultrasonic treatment significantly influences the relaxation of dislocation structure. Preliminary elastic relaxation of dislocation structure does not affect substantially the results of the following ultrasonic treatment. Substantial grain size dependence of relaxation of disordered dislocation systems is found. Simulation results are consistent with experimental data.

Hydrogen diffusion in the elastic fields of dislocations in iron

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

Sivak, A. B., E-mail: Sivak-AB@nrcki.ru; Sivak, P. A.; Romanov, V. A.

2016-12-15

The effect of dislocation stress fields on the sink efficiency thereof is studied for hydrogen interstitial atoms at temperatures of 293 and 600 K and at a dislocation density of 3 × 10{sup 14} m{sup –2} in bcc iron crystal. Rectilinear full screw and edge dislocations in basic slip systems 〈111〉(110), 〈111〉(112), 〈100〉(100), and 〈100〉(110) are considered. Diffusion of defects is simulated by means of the object kinetic Monte Carlo method. The energy of interaction between defects and dislocations is calculated using the anisotropic theory of elasticity. The elastic fields of dislocations result in a less than 25% change ofmore » the sink efficiency as compared to the noninteracting linear sink efficiency at a room temperature. The elastic fields of edge dislocations increase the dislocation sink efficiency, whereas the elastic fields of screw dislocations either decrease this parameter (in the case of dislocations with the Burgers vector being 1/2〈111〉) or do not affect it (in the case of dislocations with the Burgers vector being 〈100〉). At temperatures above 600 K, the dislocations affect the behavior of hydrogen in bcc iron mainly owing to a high binding energy between the hydrogen atom and dislocation cores.« less

Initial dislocation structure and dynamic dislocation multiplication in Mo single crystals

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

Hsiung, L M; Lassila, D H

Initial dislocation structure in annealed high-purity Mo single crystals and deformation substructure in a crystal subjected to 1% compression have been examined and studied in order to investigate dislocation multiplication mechanisms in the early stages of plastic deformation. The initial dislocation density is in a range of 10{sup 6} {approx} 10{sup 7} cm{sup -2}, and the dislocation structure is found to contain many grown-in superjogs along dislocation lines. The dislocation density increases to a range of 10{sup 8} {approx} 10{sup 9} cm{sup -2}, and the average jog height is also found to increase after compressing for a total strain ofmore » 1%. It is proposed that the preexisting jogged screw dislocations can act as (multiple) dislocation multiplication sources when deformed under quasi-static conditions. Both the jog height and length of link segment (between jogs) can increase by stress-induced jog coalescence, which takes place via the lateral migration (drift) of superjogs driven by unbalanced line-tension partials acting on link segments of unequal lengths. Applied shear stress begins to push each link segment to precede dislocation multiplication when link length and jog height are greater than critical lengths. This dynamic dislocation multiplication source is subsequently verified by direct simulations of dislocation dynamics under stress to be crucial in the early stages of plastic deformation in Mo single crystals.« less

Dislocation confinement in the growth of Na flux GaN on metalorganic chemical vapor deposition-GaN

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

Takeuchi, S., E-mail: takeuchi@ee.es.osaka-u.ac.jp; Asazu, H.; Nakamura, Y.

2015-12-28

We have demonstrated a GaN growth technique in the Na flux method to confine c-, (a+c)-, and a-type dislocations around the interface between a Na flux GaN crystal and a GaN layer grown by metalorganic chemical vapor deposition (MOCVD) on a (0001) sapphire substrate. Transmission electron microscopy (TEM) clearly revealed detailed interface structures and dislocation behaviors that reduced the density of vertically aligned dislocations threading to the Na flux GaN surface. Submicron-scale voids were formed at the interface above the dislocations with a c component in MOCVD-GaN, while no such voids were formed above the a-type dislocations. The penetration ofmore » the dislocations with a c component into Na flux GaN was, in most cases, effectively blocked by the presence of the voids. Although some dislocations with a c component in the MOCVD-GaN penetrated into the Na flux GaN, their propagation direction changed laterally through the voids. On the other hand, the a-type dislocations propagated laterally and collectively near the interface, when these dislocations in the MOCVD-GaN penetrated into the Na flux GaN. These results indicated that the dislocation propagation behavior was highly sensitive to the type of dislocation, but all types of dislocations were confined to within several micrometers region of the Na flux GaN from the interface. The cause of void formation, the role of voids in controlling the dislocation behavior, and the mechanism of lateral and collective dislocation propagation are discussed on the basis of TEM results.« less

Dislocation density evolution in the process of high-temperature treatment and creep of EK-181 steel

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

Vershinina, Tatyana, E-mail: vershinina@bsu.edu.ru

2017-03-15

X-ray diffraction has been used to study the dislocation structure in ferrite-martensite high-chromium steel EK-181 in the states after heat treatment and high-temperature creep. The influence of heat treatment and stress on evolution of lath martensite structure was investigated by and electron back-scattered diffraction. The effect of nitrogen content on the total dislocation density, fraction of edge and screw dislocation segments are analyzed. - Highlights: •Fraction of edge dislocation in quenched state depends on nitrogen concentration. •Nitrogen affects the character of dislocation structure evolution during annealing. •Edge dislocations fraction influences on dislocation density after aging and creep.

Supersonic Dislocation Bursts in Silicon

DOE PAGES

Hahn, E. N.; Zhao, S.; Bringa, E. M.; ...

2016-06-06

Dislocations are the primary agents of permanent deformation in crystalline solids. Since the theoretical prediction of supersonic dislocations over half a century ago, there is a dearth of experimental evidence supporting their existence. Here we use non-equilibrium molecular dynamics simulations of shocked silicon to reveal transient supersonic partial dislocation motion at approximately 15 km/s, faster than any previous in-silico observation. Homogeneous dislocation nucleation occurs near the shock front and supersonic dislocation motion lasts just fractions of picoseconds before the dislocations catch the shock front and decelerate back to the elastic wave speed. Applying a modified analytical equation for dislocation evolutionmore » we successfully predict a dislocation density of 1.5 x 10(12) cm(-2) within the shocked volume, in agreement with the present simulations and realistic in regards to prior and on-going recovery experiments in silicon.« less

Supersonic Dislocation Bursts in Silicon

PubMed Central

Hahn, E. N.; Zhao, S.; Bringa, E. M.; Meyers, M. A.

2016-01-01

Dislocations are the primary agents of permanent deformation in crystalline solids. Since the theoretical prediction of supersonic dislocations over half a century ago, there is a dearth of experimental evidence supporting their existence. Here we use non-equilibrium molecular dynamics simulations of shocked silicon to reveal transient supersonic partial dislocation motion at approximately 15 km/s, faster than any previous in-silico observation. Homogeneous dislocation nucleation occurs near the shock front and supersonic dislocation motion lasts just fractions of picoseconds before the dislocations catch the shock front and decelerate back to the elastic wave speed. Applying a modified analytical equation for dislocation evolution we successfully predict a dislocation density of 1.5 × 1012 cm−2 within the shocked volume, in agreement with the present simulations and realistic in regards to prior and on-going recovery experiments in silicon. PMID:27264746

Supersonic Dislocation Bursts in Silicon

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

Hahn, E. N.; Zhao, S.; Bringa, E. M.

Dislocations are the primary agents of permanent deformation in crystalline solids. Since the theoretical prediction of supersonic dislocations over half a century ago, there is a dearth of experimental evidence supporting their existence. Here we use non-equilibrium molecular dynamics simulations of shocked silicon to reveal transient supersonic partial dislocation motion at approximately 15 km/s, faster than any previous in-silico observation. Homogeneous dislocation nucleation occurs near the shock front and supersonic dislocation motion lasts just fractions of picoseconds before the dislocations catch the shock front and decelerate back to the elastic wave speed. Applying a modified analytical equation for dislocation evolutionmore » we successfully predict a dislocation density of 1.5 x 10(12) cm(-2) within the shocked volume, in agreement with the present simulations and realistic in regards to prior and on-going recovery experiments in silicon.« less

Atomistic calculations of dislocation core energy in aluminium

DOE PAGES

Zhou, X. W.; Sills, R. B.; Ward, D. K.; ...

2017-02-16

A robust molecular dynamics simulation method for calculating dislocation core energies has been developed. This method has unique advantages: it does not require artificial boundary conditions, is applicable for mixed dislocations, and can yield highly converged results regardless of the atomistic system size. Utilizing a high-fidelity bond order potential, we have applied this method in aluminium to calculate the dislocation core energy as a function of the angle β between the dislocation line and Burgers vector. These calculations show that, for the face-centred-cubic aluminium explored, the dislocation core energy follows the same functional dependence on β as the dislocation elasticmore » energy: Ec = A·sin 2β + B·cos 2β, and this dependence is independent of temperature between 100 and 300 K. By further analysing the energetics of an extended dislocation core, we elucidate the relationship between the core energy and radius of a perfect versus extended dislocation. With our methodology, the dislocation core energy can be accurately accounted for in models of plastic deformation.« less

Atomistic calculations of dislocation core energy in aluminium

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

Zhou, X. W.; Sills, R. B.; Ward, D. K.

A robust molecular dynamics simulation method for calculating dislocation core energies has been developed. This method has unique advantages: it does not require artificial boundary conditions, is applicable for mixed dislocations, and can yield highly converged results regardless of the atomistic system size. Utilizing a high-fidelity bond order potential, we have applied this method in aluminium to calculate the dislocation core energy as a function of the angle β between the dislocation line and Burgers vector. These calculations show that, for the face-centred-cubic aluminium explored, the dislocation core energy follows the same functional dependence on β as the dislocation elasticmore » energy: Ec = A·sin 2β + B·cos 2β, and this dependence is independent of temperature between 100 and 300 K. By further analysing the energetics of an extended dislocation core, we elucidate the relationship between the core energy and radius of a perfect versus extended dislocation. With our methodology, the dislocation core energy can be accurately accounted for in models of plastic deformation.« less

Dislocations

MedlinePlus

... or a blow, sometimes from playing a contact sport. You can dislocate your ankles, knees, shoulders, hips, ... to dislocate it again. Wearing protective gear during sports may help prevent dislocations.

Glide dislocation nucleation from dislocation nodes at semi-coherent {111} Cu–Ni interfaces

DOE PAGES

Shao, Shuai; Wang, Jian; Beyerlein, Irene J.; ...

2015-07-23

Using atomistic simulations and dislocation theory on a model system of semi-coherent {1 1 1} interfaces, we show that misfit dislocation nodes adopt multiple atomic arrangements corresponding to the creation and redistribution of excess volume at the nodes. We identified four distinctive node structures: volume-smeared nodes with (i) spiral or (ii) straight dislocation patterns, and volume-condensed nodes with (iii) triangular or (iv) hexagonal dislocation patterns. Volume-smeared nodes contain interfacial dislocations lying in the Cu–Ni interface but volume-condensed nodes contain two sets of interfacial dislocations in the two adjacent interfaces and jogs across the atomic layer between the two adjacent interfaces.more » Finally, under biaxial tension/compression applied parallel to the interface, we show that the nucleation of lattice dislocations is preferred at the nodes and is correlated with the reduction of excess volume at the nodes.« less

The effect of isolated dislocations on substrate and device properties in low-dislocation czochralski GaAs

NASA Astrophysics Data System (ADS)

Hunter, A. T.; Kimura, H.; Olsen, H. M.; Winston, H. V.

1986-07-01

Czochralski GaAs grown with In incorporated into the melt has large regions with fewer than 100 cm-2 dislocations. We have examined the effect of these dislocations on substrate and device properties. Infrared transmission images reveal dark filaments of high EL2 concentration a few tens of microns in diameter surrounding dislocations, Cathodo and photoluminescence images show orders of magnitude contrast in band-edge luminescence intensity near dislocations. Single dislocations appear to be surrounded by bright rings ˜200 μm in diameter in luminescence images, with dark spots 50 to 75 μm across centered on the dislocation. More complex luminescence structures with larger dark regions (˜150 μ across) and central bright spots are centered on small dislocation clusters. Differences in lifetime of photogenerated electrons or holes are the most likely cause of the luminescence contrast. Anneals typical of our post-implant processing substantially lower the luminescence contrast, suggesting the defect lowering the lifetime is removed by annealing. This may partially explain why we do not observe any effect of dislocation proximity on the properties of devices made in the material, in spite of the enormous luminescence contrast observed near dislocations.

Nonplanar core structure of the screw dislocations in tantalum from the improved Peierls-Nabarro theory

NASA Astrophysics Data System (ADS)

Hu, Xiangsheng; Wang, Shaofeng

2018-02-01

The extended structure of ? screw dislocation in Ta has been studied theoretically using the improved Peierls-Nabarro model combined with the first principles calculation. An instructive way to derive the fundamental equation for dislocations with the nonplanar structure is presented. The full ?-surface of ? plane in tantalum is evaluated from the first principles. In order to compare the energy of the screw dislocation with different structures, the structure parameter is introduced to describe the core configuration. Each kind of screw dislocation is described by an overall-shape component and a core component. Far from the dislocation centre, the asymptotic behaviour of dislocation is uniquely controlled by the overall-shape component. Near the dislocation centre, the structure detail is described by the core component. The dislocation energy is explicitly plotted as a function of the core parameter for the nonplanar dislocation as well as for the planar dislocation. It is found that in the physical regime of the core parameter, the sixfold nonplanar structure always has the lowest energy. Our result clearly confirms that the sixfold nonplanar structure is the most stable. Furthermore, the pressure effect on the dislocation structure is explored up to 100 GPa. The stability of the sixfold nonplanar structure is not changed by the applied pressure. The equilibrium structure and the related stress field are calculated, and a possible mechanism of the dislocation movement is discussed briefly based on the structure deformation caused by the external stress.

Estimation of dislocations density and distribution of dislocations during ECAP-Conform process

NASA Astrophysics Data System (ADS)

Derakhshan, Jaber Fakhimi; Parsa, Mohammad Habibi; Ayati, Vahid; Jafarian, Hamidreza

2018-01-01

Dislocation density of coarse grain aluminum AA1100 alloy (140 µm) that was severely deformed by Equal Channel Angular Pressing-Conform (ECAP-Conform) are studied at various stages of the process by electron backscattering diffraction (EBSD) method. The geometrically necessary dislocations (GNDs) density and statistically stored dislocations (SSDs) densities were estimate. Then the total dislocations densities are calculated and the dislocation distributions are presented as the contour maps. Estimated average dislocations density for annealed of about 2×1012 m-2 increases to 4×1013 m-2 at the middle of the groove (135° from the entrance), and they reach to 6.4×1013 m-2 at the end of groove just before ECAP region. Calculated average dislocations density for one pass severely deformed Al sample reached to 6.2×1014 m-2. At micrometer scale the behavior of metals especially mechanical properties largely depend on the dislocation density and dislocation distribution. So, yield stresses at different conditions were estimated based on the calculated dislocation densities. Then estimated yield stresses were compared with experimental results and good agreements were found. Although grain size of material did not clearly change, yield stress shown intensive increase due to the development of cell structure. A considerable increase in dislocations density in this process is a good justification for forming subgrains and cell structures during process which it can be reason of increasing in yield stress.

[New varieties of lateral metatarsophalangeal dislocations of the great toe].

PubMed

Bousselmame, N; Rachid, K; Lazrak, K; Galuia, F; Taobane, H; Moulay, I

2001-04-01

We report seven cases of traumatic dislocation of the great toe, detailing the anatomy, the mechanism of injury and the radiographic diagnosis. We propose an additional classification based on three hereto unreported cases. Between october 1994 and october 1997, we treated seven patients with traumatic dislocation of the first metatarso-phalangeal joint of the great toe. There were six men and one woman, mean age 35 years (range 24 - 44 years). Dislocation was caused by motor vehicle accidents in four cases and by falls in three. Diagnosis was made on anteroposterior, lateral and medial oblique radiographs. According to Jahss' classification, there was one type I and three type IIB dislocations. There was also one open lateral dislocation and two dorsomedial dislocations. Only these dorsomedial dislocations required open reduction, done via a dorsal approach. Mean follow-up was 17.5 months (range 9 - 24 months) in six cases. One patient was lost to follow-up. The outcome was good in six cases and poor in one (dorsomedial dislocation). Dislocation of the first metatarso-phalangeal joint of the great toe is an uncommon injury. In 1980, Jahss reported two cases and reviewed three others described in the literature. He proposed three types of dislocation based on the feasibility of closed reduction (type I, II and IIB). In 1991, Copeland and Kanat reported a unique case in which there was an association of IIA and IIB lesions. They proposed an addition to the classification (type IIC). In 1994, Garcia Mata et al. reported another case which had not been described by Jahss and proposed another addition. All dislocations reported to date have been sagittal dislocations. Pathological alteration of the collateral ligaments has not been previously reported. In our experience, we have seen one case of open lateral dislocation due, at surgical exploration, to medial ligament rupture and two cases of dorsomedial dislocation due, at surgical exploration, to lateral ligament rupture. We propose another additional classification with pure lateral dislocation (type III) and dorso-lateral dislocation (type IL or IIL+), which are related to the formerly described variants.

Quantifying the effect of hydrogen on dislocation dynamics: A three-dimensional discrete dislocation dynamics framework

NASA Astrophysics Data System (ADS)

Gu, Yejun; El-Awady, Jaafar A.

2018-03-01

We present a new framework to quantify the effect of hydrogen on dislocations using large scale three-dimensional (3D) discrete dislocation dynamics (DDD) simulations. In this model, the first order elastic interaction energy associated with the hydrogen-induced volume change is accounted for. The three-dimensional stress tensor induced by hydrogen concentration, which is in equilibrium with respect to the dislocation stress field, is derived using the Eshelby inclusion model, while the hydrogen bulk diffusion is treated as a continuum process. This newly developed framework is utilized to quantify the effect of different hydrogen concentrations on the dynamics of a glide dislocation in the absence of an applied stress field as well as on the spacing between dislocations in an array of parallel edge dislocations. A shielding effect is observed for materials having a large hydrogen diffusion coefficient, with the shield effect leading to the homogenization of the shrinkage process leading to the glide loop maintaining its circular shape, as well as resulting in a decrease in dislocation separation distances in the array of parallel edge dislocations. On the other hand, for materials having a small hydrogen diffusion coefficient, the high hydrogen concentrations around the edge characters of the dislocations act to pin them. Higher stresses are required to be able to unpin the dislocations from the hydrogen clouds surrounding them. Finally, this new framework can open the door for further large scale studies on the effect of hydrogen on the different aspects of dislocation-mediated plasticity in metals. With minor modifications of the current formulations, the framework can also be extended to account for general inclusion-induced stress field in discrete dislocation dynamics simulations.

Diabetes Mellitus Alters the Mechanical Properties of the Native Tendon in an Experimental Rat Model

PubMed Central

Fox, Alice J. S.; Bedi, Asheesh; Deng, Xiang-Hua; Ying, Liang; Harris, Paul E.; Warren, Russell F.; Rodeo, Scott A.

2017-01-01

The purpose of this study was to determine the effect of the diabetic phenotype on the mechanical properties of the native patellar tendon and its enthesis. Diabetes was induced via intraperitoneal injection of streptozotocin in Lewis rats. Control (n = 18) and diabetic animals(n = 20) were killed at 12 and 19 days for analysis. Statistical comparisons were performed using Student’s t-tests and a two-tailed Fisher test with significance set at p < 0.05. Pre- and post-injection intraperitoneal glucose tolerance tests demonstrated significant impairment of glycemic control in the diabetic compared to control animals (p = 0.001). Mean serum hemoglobin A1c levels at 19 days was 10.6 ± 2.7% and 6.0 ± 1.0% for the diabetic and control groups, respectively (p = 0.0001). Fifteen of sixteen diabetic animals demonstrated intrasubstance failure of the patellar tendon, while only 7 of 14 control specimens failed within the tendon substance. The Young’s modulus of the diabetic tendon was significantly lower than control specimens by 19 days post-induction (161 ± 10 N m−2 compared to 200 ± 46 N m−2, respectively) (p = 0.02). The metabolic condition of poorly controlled diabetes negatively affects the mechanical properties of the native patellar tendon. These altered structural properties may predispose diabetic patients to a greater risk of tendinopathy and/or traumatic rupture. PMID:21246619

Sleeve fracture of the adult patella

PubMed Central

Xie, Linjun; Xu, Hong; Zhang, Lizhi; Xu, Rong; Guo, Yingkun

2017-01-01

Abstract Rationale: The patellar fractures are common in adults, but rare in children. As a particular type of patellar fracture, however, sleeve fractures are almost always limited to children in the under 16's group. Patient concerns: Herein, we report a rare case of a 19-year-old healthy adult female who presented sleeve fracture at the superior pole of the left patella. The clinical and radiological features are found including joint effusion, anterior tilt of the patella and a shell of bone lying proximally to the patella. Diagnoses: Computed tomography and magnetic resonance imaging examination have been performed to further confirm the diagnosis of sleeve fracture, rupture of the quadriceps tendon and the cartilaginous injury. Interventions: Under general anaesthesia, she underwent open surgical procedures for reconstituting anatomically the fracture and repairing the rupture of the quadriceps tendon. Outcomes: Six months after the operation, she could fully use her left knee without any pain and disability. Lessons: Sleeve fractures of the patellar in adults are extremely rare, and our case is of interest for the first time occurring in healthy female adults. Our case report and literature review was aim to describe the clinic and imaging characteristics of superior pole sleeve fractures in adults, and highlight that physicians must be aware of this entity in adults so as to reduce misdiagnosis due to unfamiliarity. PMID:28796028

Volumetric characterization of human patellar cartilage matrix on phase contrast x-ray computed tomography

NASA Astrophysics Data System (ADS)

Abidin, Anas Z.; Nagarajan, Mahesh B.; Checefsky, Walter A.; Coan, Paola; Diemoz, Paul C.; Hobbs, Susan K.; Huber, Markus B.; Wismüller, Axel

2015-03-01

Phase contrast X-ray computed tomography (PCI-CT) has recently emerged as a novel imaging technique that allows visualization of cartilage soft tissue, subsequent examination of chondrocyte patterns, and their correlation to osteoarthritis. Previous studies have shown that 2D texture features are effective at distinguishing between healthy and osteoarthritic regions of interest annotated in the radial zone of cartilage matrix on PCI-CT images. In this study, we further extend the texture analysis to 3D and investigate the ability of volumetric texture features at characterizing chondrocyte patterns in the cartilage matrix for purposes of classification. Here, we extracted volumetric texture features derived from Minkowski Functionals and gray-level co-occurrence matrices (GLCM) from 496 volumes of interest (VOI) annotated on PCI-CT images of human patellar cartilage specimens. The extracted features were then used in a machine-learning task involving support vector regression to classify ROIs as healthy or osteoarthritic. Classification performance was evaluated using the area under the receiver operating characteristic (ROC) curve (AUC). The best classification performance was observed with GLCM features correlation (AUC = 0.83 +/- 0.06) and homogeneity (AUC = 0.82 +/- 0.07), which significantly outperformed all Minkowski Functionals (p < 0.05). These results suggest that such quantitative analysis of chondrocyte patterns in human patellar cartilage matrix involving GLCM-derived statistical features can distinguish between healthy and osteoarthritic tissue with high accuracy.

Infrapatellar fat pad disruption: a radiographic sign of patellar tendon rupture.

PubMed

Chin, Kingsley R; Sodl, Jeffrey F

2005-11-01

After knee trauma, radiographs showing patella alta supercede other signs that suggest patellar tendon rupture. However, without patella alta the diagnosis may be missed. A standard lateral radiograph with the knee flexed showed the infrapatellar fat pad as a dark band with a smooth contour. Our pilot study identified a disruption of the fat pad contour as a radiographic sign of tendon rupture. Two blinded reviewers independently analyzed randomly selected lateral radiographs of the knees of 14 patients with knee injuries. Seven patients had confirmed ruptures diagnosed at surgery, and the other patients had different diagnoses. There were 12 men and two women with an average age of 49 years (range, 20-81 years). One observer detected five of the seven disrupted tendons and six of the seven intact tendons. The other observer detected six of the seven disrupted tendons and all seven intact tendons. Disruption in the contour of the infrapatellar fat pad on routine lateral view radiographs was a reasonably reliable sign of patellar tendon rupture. Diagnostic accuracy should increase when used with the patient's history, physical examination, and other radiographic signs. Absence of this sign should not supersede other suggestive signs of patella tendon rupture. Diagnostic study, Level II (development of diagnostic criteria on consecutive patients--with universally applied reference "gold" standard). See the Guidelines for Authors for a complete description of levels of evidence.

Oxidized zirconium versus cobalt-chromium against the native patella in total knee arthroplasty: Patellofemoral outcomes.

PubMed

Matassi, Fabrizio; Paoli, Tommaso; Civinini, Roberto; Carulli, Christian; Innocenti, Massimo

2017-10-01

Oxidized zirconium (OxZr) has demonstrated excellent mechanical properties in vitro when used against articular cartilage; less coefficient of friction and less chondral damage have been found when compared with cobalt-chromium (CoCr) implants. However, controversy exists as to whether implants with a zirconium femoral component articulate safely with a native patella in total knee arthroplasty (TKA). To answer this question, the clinical and radiographic results were analysed from a group of patients who underwent a TKA with patella retention; the OxZr versus CoCr femoral components were compared. The present study prospectively evaluated 83 knees of 74 patients from 2009 to 2010. Each patient was evaluated clinically (visual analogue scale, Knee Society score, patellar score) and radiographically (long leg standing radiograph, anterior-posterior and latero-lateral projections, axial view of the patella) pre-operatively and postoperatively with a mean follow-up of 4.47years. The patellar tilt and shift, and progression of patellofemoral osteoarthritis were calculated with the axial view. There were no patient reported adverse reactions and none of the evaluated prostheses failed. Both the clinical and radiographic evaluations showed no statistically significant between-group differences. No adverse events were observed clinically or radiologically. These results justify pursuing the use of oxidized zirconium as an alternative bearing surface for a femoral component associated with patellar retention in TKA. Published by Elsevier B.V.

Dislocation-induced stress in polycrystalline materials: mesoscopic simulations in the dislocation density formalism

NASA Astrophysics Data System (ADS)

Berkov, D. V.; Gorn, N. L.

2018-06-01

In this paper we present a simple and effective numerical method which allows a fast Fourier transformation-based evaluation of stress generated by dislocations with arbitrary directions and Burgers vectors if the (site-dependent) dislocation density is known. Our method allows the evaluation of the dislocation stress using a rectangular grid with shape-anisotropic discretization cells without employing higher multipole moments of the dislocation interaction coefficients. Using the proposed method, we first simulate the stress created by relatively simple non-homogeneous distributions of vertical edge and so-called ‘mixed’ dislocations in a disk-shaped sample, which is necessary to understand the dislocation behavior in more complicated systems. The main part of our research is devoted to the stress distribution in polycrystalline layers with the dislocation density rapidly varying with the distance to the layer bottom. Considering GaN as a typical example of such systems, we investigate dislocation-induced stress for edge and mixed dislocations, having random orientations of Burgers vectors among crystal grains. We show that the rapid decay of the dislocation density leads to many highly non-trivial features of the stress distributions in such layers and study in detail the dependence of these features on the average grain size. Finally we develop an analytical approach which allows us to predict the evolution of the stress variance with the grain size and compare analytical predictions with numerical results.

20 CFR 663.115 - What are the eligibility criteria for core services for dislocated workers in the adult and...

Code of Federal Regulations, 2012 CFR

2012-04-01

... services for dislocated workers in the adult and dislocated worker programs? 663.115 Section 663.115 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated...

20 CFR 663.115 - What are the eligibility criteria for core services for dislocated workers in the adult and...

Code of Federal Regulations, 2014 CFR

2014-04-01

... services for dislocated workers in the adult and dislocated worker programs? 663.115 Section 663.115 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated...

20 CFR 663.115 - What are the eligibility criteria for core services for dislocated workers in the adult and...

Code of Federal Regulations, 2013 CFR

2013-04-01

... services for dislocated workers in the adult and dislocated worker programs? 663.115 Section 663.115 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated...

Dislocation pinning effects induced by nano-precipitates during warm laser shock peening: Dislocation dynamic simulation and experiments

NASA Astrophysics Data System (ADS)

Liao, Yiliang; Ye, Chang; Gao, Huang; Kim, Bong-Joong; Suslov, Sergey; Stach, Eric A.; Cheng, Gary J.

2011-07-01

Warm laser shock peening (WLSP) is a new high strain rate surface strengthening process that has been demonstrated to significantly improve the fatigue performance of metallic components. This improvement is mainly due to the interaction of dislocations with highly dense nanoscale precipitates, which are generated by dynamic precipitation during the WLSP process. In this paper, the dislocation pinning effects induced by the nanoscale precipitates during WLSP are systematically studied. Aluminum alloy 6061 and AISI 4140 steel are selected as the materials with which to conduct WLSP experiments. Multiscale discrete dislocation dynamics (MDDD) simulation is conducted in order to investigate the interaction of dislocations and precipitates during the shock wave propagation. The evolution of dislocation structures during the shock wave propagation is studied. The dislocation structures after WLSP are characterized via transmission electron microscopy and are compared with the results of the MDDD simulation. The results show that nano-precipitates facilitate the generation of highly dense and uniformly distributed dislocation structures. The dislocation pinning effect is strongly affected by the density, size, and space distribution of nano-precipitates.

“Conjugate Channeling” Effect in Dislocation Core Diffusion: Carbon Transport in Dislocated BCC Iron

PubMed Central

Ishii, Akio; Li, Ju; Ogata, Shigenobu

2013-01-01

Dislocation pipe diffusion seems to be a well-established phenomenon. Here we demonstrate an unexpected effect, that the migration of interstitials such as carbon in iron may be accelerated not in the dislocation line direction , but in a conjugate diffusion direction. This accelerated random walk arises from a simple crystallographic channeling effect. is a function of the Burgers vector b, but not , thus a dislocation loop possesses the same everywhere. Using molecular dynamics and accelerated dynamics simulations, we further show that such dislocation-core-coupled carbon diffusion in iron has temperature-dependent activation enthalpy like a fragile glass. The 71° mixed dislocation is the only case in which we see straightforward pipe diffusion that does not depend on dislocation mobility. PMID:23593255

"Conjugate channeling" effect in dislocation core diffusion: carbon transport in dislocated BCC iron.

PubMed

Ishii, Akio; Li, Ju; Ogata, Shigenobu

2013-01-01

Dislocation pipe diffusion seems to be a well-established phenomenon. Here we demonstrate an unexpected effect, that the migration of interstitials such as carbon in iron may be accelerated not in the dislocation line direction ξ, but in a conjugate diffusion direction. This accelerated random walk arises from a simple crystallographic channeling effect. c is a function of the Burgers vector b, but not ξ, thus a dislocation loop possesses the same everywhere. Using molecular dynamics and accelerated dynamics simulations, we further show that such dislocation-core-coupled carbon diffusion in iron has temperature-dependent activation enthalpy like a fragile glass. The 71° mixed dislocation is the only case in which we see straightforward pipe diffusion that does not depend on dislocation mobility.

BBilateral Neglected Anterior Shoulder Dislocation with Greater Tuberosity Fractures

PubMed Central

Upasani, Tejas; Bhatnagar, Abhinav; Mehta, Sonu

2016-01-01

Introduction: Shoulder dislocations are a very common entity in routine orthopaedic practice. Chronic unreduced anterior dislocations of the shoulder are not very common. Neurological and vascular complications may occur as a result of an acute anterior dislocation of the shoulder or after a while in chronic unreduced shoulder dislocation. Open reduction is indicated for most chronic shoulder dislocations. We report a case of neglected bilateral anterior shoulder dislocation with bilateral displaced greater tuberosity fracture. To the best of our knowledge, only a handful cases have been reported in literature with bilateral anterior shoulder dislocation with bilateral fractures. Delayed diagnosis/reporting is a scenario which makes the list even slimmer and management all the more challenging. Case Report: We report a case of a 35-year-old male who had bilateral anterior shoulder dislocation and bilateral greater tuberosity fracture post seizure and failed to report it for a period of 30 days. One side was managed conservatively with closed reduction and immobilization and the other side with open reduction. No neurovascular complications pre or post reduction of shoulder were seen. Conclusion: Shoulder dislocations should always be suspected post seizures and if found should be treated promptly. Treatment becomes difficult for any shoulder dislocation that goes untreated for considerable period of time PMID:27703939

Dynamics and Removal Pathway of Edge Dislocations in Imperfectly Attached PbTe Nanocrystal Pairs: Toward Design Rules for Oriented Attachment.

PubMed

Ondry, Justin C; Hauwiller, Matthew R; Alivisatos, A Paul

2018-04-24

Using in situ high-resolution TEM, we study the structure and dynamics of well-defined edge dislocations in imperfectly attached PbTe nanocrystals. We identify that attachment of PbTe nanocrystals on both {100} and {110} facets gives rise to b = a/2⟨110⟩ edge dislocations. Based on the Burgers vector of individual dislocations, we can identify the glide plane of the dislocations. We observe that defects in particles attached on {100} facets have glide planes that quickly intersect the surface, and HRTEM movies show that the defects follow the glide plane to the surface. For {110} attached particles, the glide plane is collinear with the attachment direction, which does not provide an easy path for the dislocation to reach the surface. Indeed, HRTEM movies of dislocations for {110} attached particles show that defect removal is much slower. Further, we observe conversion from pure edge dislocations in imperfectly attached particles to dislocations with mixed edge and screw character, which has important implications for crystal growth. Finally, we observe that dislocations initially closer to the surface have a higher speed of removal, consistent with the strong dislocation free surface attractive force. Our results provide important design rules for defect-free attachment of preformed nanocrystals into epitaxial assemblies.

[Therapy of traumatic anterior shoulder dislocation: current status of therapy in Germany. Are there scientifically verified therapy concepts?].

PubMed

Tingart, M; Bäthis, H; Bouillon, B; Tiling, T

2001-06-01

There are no generally accepted concepts for the treatment of traumatic anterior shoulder dislocation. The objective of this study was to ascertain the current treatment for traumatic shoulder dislocations in German hospitals and to compare this with the data reported in the literature. A total of 210 orthopedic surgery departments were asked for their treatment strategy in an anonymous country-wide survey; 103 questionnaires (49%) were returned for evaluation. Additional imaging (ultrasound, CT, MRI) beyond the routine X-rays is performed in 82% of clinics for primary shoulder dislocation (94% in recurrent dislocation). A young, athletic patient (< 30 years old) would be operated on for a primary traumatic shoulder dislocation in 73% of hospitals (98% in recurrent dislocation). In contrast, a patient of the same age, with a moderate level of sporting activity would be treated conservatively in 67% of cases (14% in recurrent dislocation). Similarly, for an active, middle-aged patient with a demanding job, 74% of responses favored conservative treatment after a primary dislocation and 6% after a recurrent dislocation. Older patients (> 65 years old) are usually treated conservatively after a primary or recurrent shoulder dislocation (99%, 69%). For a primary shoulder dislocation the most popular surgical reconstruction is a Bankart repair (75%). For recurrent shoulder dislocation several different operative techniques are seen (Bankart 29%, T-shift 26%, Putti-Platt 8%, Eden-Lange-Hybbinette 22%, Weber osteotomy 13%). Based on our literature review, we found: (1) The clinical examination of both shoulders is important to diagnose hyperlaxity; (2) Routine CT or MRI is not necessary for primary traumatic shoulder dislocations; (3) A young, athletic patient should undergo surgical reconstruction after a primary shoulder dislocation; (4) The operation of choice for primary and recurrent dislocation is the Bankart repair; (5) There is no sufficient evidence that an arthroscopic Bankart repair is as good as an open procedure; (6) There are limited indications for other operative techniques, as they are associated with a higher recurrence and arthrosis rate.

20 CFR 663.115 - What are the eligibility criteria for core services for dislocated workers in the adult and...

Code of Federal Regulations, 2011 CFR

2011-04-01

... services for dislocated workers in the adult and dislocated worker programs? 663.115 Section 663.115 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR ADULT AND DISLOCATED WORKER ACTIVITIES UNDER TITLE I OF THE WORKFORCE INVESTMENT ACT Delivery of Adult and Dislocated Worker Services...

Using O*NET in Dislocated Worker Retraining: The Toledo Dislocated Worker Consortium Project.

ERIC Educational Resources Information Center

Sommers, Dixie; Austin, James

A project used the Occupational Information Network (O*NET) to assist eligible dislocated workers in determining whether training offered by the Toledo Dislocated Worker Consortium fit their needs. More specifically, O*NET was used to help the dislocated workers understand whether they had knowledge and skills that were transferable into the…

A micro S-shaped optical fiber temperature sensor based on dislocation fiber splice

NASA Astrophysics Data System (ADS)

Yan, Haitao; Li, Pengfei; Zhang, Haojie; Shen, Xiaoyue; Wang, Yongzhen

2017-12-01

We fabricated a simple, compact, and stable temperature sensor based on an S-shaped dislocated optical fiber. The dislocation optical fiber has two splice points, and we obtained the optimal parameters based on the theory and our experiment, such as the dislocation amount and length of the dislocation optical fiber. According to the relationship between the temperature and the peak wavelength shift, the temperature of the environment can be obtained. Then, we made this fiber a micro bending as S-shape between the two dislocation points, and the S-shaped micro bending part could release stress with the change in temperature and reduce the effect of stress on the temperature measurement. This structure could solve the problem of sensor distortion caused by the cross response of temperature and stress. We measured the S-shaped dislocation fiber sensor and the dislocation fiber without S-shape under the same environment and conditions, and the S-shaped dislocation fiber had the advantages of the stable reliability and good linearity.

Quasicontinuum analysis of dislocation-coherent twin boundary interaction to provide local rules to discrete dislocation dynamics

NASA Astrophysics Data System (ADS)

Tran, H.-S.; Tummala, H.; Duchene, L.; Pardoen, T.; Fivel, M.; Habraken, A. M.

2017-10-01

The interaction of a pure screw dislocation with a Coherent Twin Boundary Σ3 in copper was studied using the Quasicontinuum method. Coherent Twin Boundary behaves as a strong barrier to dislocation glide and prohibits slip transmission across the boundary. Dislocation pileup modifies the stress field at its intersection with the Grain Boundary (GB). A methodology to estimate the strength of the barrier for a dislocation to slip across CTB is proposed. A screw dislocation approaching the boundary from one side either propagates into the adjacent twin grain by cutting through the twin boundary or is stopped and increases the dislocation pileup amplitude at the GB. Quantitative estimation of the critical stress for transmission was performed using the virial stress computed by Quasicontinuum method. The transmission mechanism and critical stress are in line with the literature. Such information can be used as input for dislocation dynamic simulations for a better modeling of grain boundaries.

A phase field crystal model simulation of morphology evolution and misfit dislocation generation in nanoheteroepitaxy

NASA Astrophysics Data System (ADS)

Zhang, J.; Chen, Z.; Cheng, C.; Wang, Y. X.

2017-10-01

A phase field crystal (PFC) model is employed to study morphology evolution of nanoheteroepitaxy and misfit dislocation generation when applied with enhanced supercooling, lattice mismatch and substrate vicinal angle conditions. Misfit strain that rises due to lattice mismatch causes rough surfaces or misfit dislocations, deteriorates film properties, hence, efforts taken to reveal their microscopic mechanism are significant for film quality improvement. Uniform islands, instead of misfit dislocations, are developed in subcritical thickness film, serving as a way of strain relief by surface mechanism. Misfit dislocations generate when strain relief by surface mechanism is deficient in higher supercooling, multilayers of misfit dislocations dominate, but the number of layers reduces gradually when the supercooling is further enhanced. Rough surfaces like islands or cuspate pits are developed which is ascribed to lattice mismatch, multilayers of misfit dislocations generate to further enhance lattice mismatch. Layers of misfit dislocations generate at a thickening position at enhanced substrate vicinal angle, this further enhancing the angle leading to sporadic generation of misfit dislocations.

Complex and noncentrosymmetric stacking of layered metal dichalcogenide materials created by screw dislocations

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

Shearer, Melinda J.; Samad, Leith; Zhang, Yi

The interesting and tunable properties of layered metal dichalcogenides heavily depend on their phase and layer stacking. Here, we show and explain how the layer stacking and physical properties of WSe 2 are influenced by screw dislocations. A one-to-one correlation of atomic force microscopy and high- and low-frequency Raman spectroscopy of many dislocated WSe 2 nanoplates reveals variations in the number and shapes of dislocation spirals and different layer stackings that are determined by the number, rotation, and location of the dislocations. Plates with triangular dislocation spirals form noncentrosymmetric stacking that gives rise to strong second-harmonic generation and enhanced photoluminescence,more » plates with hexagonal dislocation spirals form the bulk 2H layer stacking commonly observed, and plates containing mixed dislocation shapes have intermediate noncentrosymmetric stackings with mixed properties. Multiple dislocation cores and other complexities can lead to more complex stackings and properties. Finally, these previously unobserved properties and layer stackings in WSe 2 will be interesting for spintronics and valleytronics.« less

Complex and noncentrosymmetric stacking of layered metal dichalcogenide materials created by screw dislocations

DOE PAGES

Shearer, Melinda J.; Samad, Leith; Zhang, Yi; ...

2017-02-08

The interesting and tunable properties of layered metal dichalcogenides heavily depend on their phase and layer stacking. Here, we show and explain how the layer stacking and physical properties of WSe 2 are influenced by screw dislocations. A one-to-one correlation of atomic force microscopy and high- and low-frequency Raman spectroscopy of many dislocated WSe 2 nanoplates reveals variations in the number and shapes of dislocation spirals and different layer stackings that are determined by the number, rotation, and location of the dislocations. Plates with triangular dislocation spirals form noncentrosymmetric stacking that gives rise to strong second-harmonic generation and enhanced photoluminescence,more » plates with hexagonal dislocation spirals form the bulk 2H layer stacking commonly observed, and plates containing mixed dislocation shapes have intermediate noncentrosymmetric stackings with mixed properties. Multiple dislocation cores and other complexities can lead to more complex stackings and properties. Finally, these previously unobserved properties and layer stackings in WSe 2 will be interesting for spintronics and valleytronics.« less

Motion of 1/3⟨111⟩ dislocations on Σ3 {112} twin boundaries in nanotwinned copper

NASA Astrophysics Data System (ADS)

Lu, N.; Du, K.; Lu, L.; Ye, H. Q.

2014-01-01

The atomic structure of Σ3 {112} ITBs in nanotwinned Cu is investigated by using aberration-corrected high resolution transmission electron microscopy (HRTEM) and in situ HRTEM observations. The Σ3 {112} ITBs are consisted of periodically repeated three partial dislocations. The in situ HRTEM results show that 1/3[111] partial dislocation moves on the Σ3 {112} incoherent twin boundary (ITB), which was accompanied by a migration of the ITB. A dislocation reaction mechanism is proposed for the motion of 1/3[111] Frank partial dislocation, in which the 1/3[111] partial dislocation exchanges its position with twin boundary dislocations in sequence. In this way, the 1/3[111] dislocation can move on the incoherent twin boundary in metals with low stacking fault energy. Meanwhile, the ITB will migrate in its normal direction accordingly. These results provide insight into the reaction mechanism of 1/3[111] dislocations and ITBs and the associated migration of ITBs.

Complete dislocation of the ulnar nerve at the elbow: a protective effect against neuropathy?

PubMed

Leis, A Arturo; Smith, Benn E; Kosiorek, Heidi E; Omejec, Gregor; Podnar, Simon

2017-08-01

Recurrent complete ulnar nerve dislocation has been perceived as a risk factor for development of ulnar neuropathy at the elbow (UNE). However, the role of dislocation in the pathogenesis of UNE remains uncertain. We studied 133 patients with complete ulnar nerve dislocation to determine whether this condition is a risk factor for UNE. In all, the nerve was palpated as it rolled over the medial epicondyle during elbow flexion. Of 56 elbows with unilateral dislocation, UNE localized contralaterally in 17 elbows (30.4%) and ipsilaterally in 10 elbows (17.9%). Of 154 elbows with bilateral dislocation, 26 had UNE (16.9%). Complete dislocation decreased the odds of having UNE by 44% (odds ratio = 0.475; P =  0.028), and was associated with less severe UNE (P = 0.045). UNE occurs less frequently and is less severe on the side of complete dislocation. Complete dislocation may have a protective effect on the ulnar nerve. Muscle Nerve 56: 242-246, 2017. © 2016 Wiley Periodicals, Inc.

Unravelling the physics of size-dependent dislocation-mediated plasticity

NASA Astrophysics Data System (ADS)

El-Awady, Jaafar A.

2015-01-01

Size-affected dislocation-mediated plasticity is important in a wide range of materials and technologies. Here we develop a generalized size-dependent dislocation-based model that predicts strength as a function of crystal/grain size and the dislocation density. Three-dimensional (3D) discrete dislocation dynamics (DDD) simulations reveal the existence of a well-defined relationship between strength and dislocation microstructure at all length scales for both single crystals and polycrystalline materials. The results predict a transition from dislocation-source strengthening to forest-dominated strengthening at a size-dependent critical dislocation density. It is also shown that the Hall-Petch relationship can be physically interpreted by coupling with an appropriate kinetic equation of the evolution of the dislocation density in polycrystals. The model is shown to be in remarkable agreement with experiments. This work presents a micro-mechanistic framework to predict and interpret strength size-scale effects, and provides an avenue towards performing multiscale simulations without ad hoc assumptions.

Characteristics of dislocation structure in creep deformed lamellar tial alloy within primary regime

NASA Astrophysics Data System (ADS)

Cho, H. S.; Nam, Soo W.

1999-06-01

In this investigation, dislocations of a lamellar TiAl alloy are analyzed after creeping in the primary range at 800°C/200MPa in order to interpret their mobility It was found that the dislocation density in γ-laths decreased as the creep deformation proceeds within primary creep regime Schmid factor analysis suggests that the creep deformation in the early stage of the primary creep regime is controlled by the gliding of some of the initial dislocations which have a high enough Schmid factor As the creep deformation progressed, those dislocations with high Schmid factors slip preferentially to be annihilated at the α-γ interface For further continuous deformation, dislocation generation is required, and for this, α-phase is transformed to γ-phase in order to generate new dislocations A slow dislocation generation process by phase transformation of α-phase compared with the absorbing rate to sinks is responsible for the decreasing dislocation density as the creep strain increases

Strain field mapping of dislocations in a Ge/Si heterostructure.

PubMed

Liu, Quanlong; Zhao, Chunwang; Su, Shaojian; Li, Jijun; Xing, Yongming; Cheng, Buwen

2013-01-01

Ge/Si heterostructure with fully strain-relaxed Ge film was grown on a Si (001) substrate by using a two-step process by ultra-high vacuum chemical vapor deposition. The dislocations in the Ge/Si heterostructure were experimentally investigated by high-resolution transmission electron microscopy (HRTEM). The dislocations at the Ge/Si interface were identified to be 90° full-edge dislocations, which are the most efficient way for obtaining a fully relaxed Ge film. The only defect found in the Ge epitaxial film was a 60° dislocation. The nanoscale strain field of the dislocations was mapped by geometric phase analysis technique from the HRTEM image. The strain field around the edge component of the 60° dislocation core was compared with those of the Peierls-Nabarro and Foreman dislocation models. Comparison results show that the Foreman model with a = 1.5 can describe appropriately the strain field around the edge component of a 60° dislocation core in a relaxed Ge film on a Si substrate.

Effect of solute atoms on dislocation motion in Mg: An electronic structure perspective

PubMed Central

Tsuru, T.; Chrzan, D. C.

2015-01-01

Solution strengthening is a well-known approach to tailoring the mechanical properties of structural alloys. Ultimately, the properties of the dislocation/solute interaction are rooted in the electronic structure of the alloy. Accordingly, we compute the electronic structure associated with, and the energy barriers to dislocation cross-slip. The energy barriers so obtained can be used in the development of multiscale models for dislocation mediated plasticity. The computed electronic structure can be used to identify substitutional solutes likely to interact strongly with the dislocation. Using the example of a-type screw dislocations in Mg, we compute accurately the Peierls barrier to prismatic plane slip and argue that Y, Ca, Ti, and Zr should interact strongly with the studied dislocation, and thereby decrease the dislocation slip anisotropy in the alloy. PMID:25740411

Deformation twinning in a creep-deformed nanolaminate structure

NASA Astrophysics Data System (ADS)

Hsiung, Luke L.

2010-10-01

The underlying mechanism of deformation twinning occurring in a TiAl-(γ)/Ti3Al-(α2) nanolaminate creep deformed at elevated temperatures has been studied. Since the multiplication and propagation of lattice dislocations in both γ and α2 thin lamellae are very limited, the total flow of lattice dislocations becomes insufficient to accommodate the accumulated creep strains. Consequently, the movement of interfacial dislocations along the laminate interfaces, i.e., interface sliding, becomes an alternative deformation mode of the nanolaminate structure. Pile-ups of interfacial dislocations occur when interfacial ledges and impinged lattice dislocations act as obstacles to impede the movement of interfacial dislocations. Deformation twinning can accordingly take place to relieve a stress concentration resulting from the pile-up of interfacial dislocations. An interface-controlled twinning mechanism driven by the pile-up and dissociation of interfacial dislocations is accordingly proposed.

Dislocation dynamics in hexagonal close-packed crystals

DOE PAGES

Aubry, S.; Rhee, M.; Hommes, G.; ...

2016-04-14

Extensions of the dislocation dynamics methodology necessary to enable accurate simulations of crystal plasticity in hexagonal close-packed (HCP) metals are presented. They concern the introduction of dislocation motion in HCP crystals through linear and non-linear mobility laws, as well as the treatment of composite dislocation physics. Formation, stability and dissociation of and other dislocations with large Burgers vectors defined as composite dislocations are examined and a new topological operation is proposed to enable their dissociation. Furthermore, the results of our simulations suggest that composite dislocations are omnipresent and may play important roles both in specific dislocation mechanisms and in bulkmore » crystal plasticity in HCP materials. While fully microscopic, our bulk DD simulations provide wealth of data that can be used to develop and parameterize constitutive models of crystal plasticity at the mesoscale.« less

Dislocation loop models for the high temperature creep of Al-5.5 at.% Mg alloy

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

An, S.U.; Blum, W.

1995-04-15

The Al-5.5 at.% Mg alloy is a typical class I type solution hardened material. The dislocation loop models proposed by Orlova and Cadek and by Mills et al., respectively are widely applied models in describing the high temperature creep behavior of the Al-5.5 at.% Mg alloy. These models, however, are in conflict in explaining dislocation loop theory. Orlova and Cadek suggest that in class I solution hardened alloys screw dislocations are relatively easier to migrate because they are subject to a smaller resistance in motion than edge dislocations. Consequently, the migration rate of screw dislocations is higher than that ofmore » edge dislocations. However, since dislocation loops are composed of both screw and edge components, the overall migration rate of screw dislocations are reduced by that of the edge component. Mills et al. on the contrary, used a different dislocation loop model. As the loop grows while it moves, it takes on the shape of an ellipsoid due to the unbalance in growth rate, the score segment moving much easier than the edge. Therefore, as shown in the results of the stress reduction tests, rapid elastic ({Delta} {var_epsilon}{sub el}) and anelastic contraction ({Delta} {var_epsilon}{sub an}) occur simultaneously directly after stress reduction. During the movement of the dislocation loop, the screw component hence becomes severely curved, while the edge component retains a straight line. This has been proved through dislocation structure observations by TEM.« less

Dislocation pileup as a representation of strain accumulation on a strike-slip fault

USGS Publications Warehouse

Savage, J.C.

2006-01-01

The conventional model of strain accumulation on a vertical transform fault is a discrete screw dislocation in an elastic half-space with the Burgers vector of the dislocation increasing at the rate of relative plate motion. It would be more realistic to replace that discrete dislocation by a dislocation distribution, presumably a pileup in which the individual dislocations are in equilibrium. The length of the pileup depends upon the applied stress and the amount of slip that has occurred at depth. I argue here that the dislocation pileup (the transition on the fault from no slip to slip at the full plate rate) occupies a substantial portion of the lithosphere thickness. A discrete dislocation at an adjustable depth can reproduce the surface deformation profile predicted by a pileup so closely that it will be difficult to distinguish between the two models. The locking depth (dislocation depth) of that discrete dislocation approximation is substantially (???30%) larger than that (depth to top of the pileup) in the pileup model. Thus, in inverting surface deformation data using the discrete dislocation model, the locking depth in the model should not be interpreted as the true locking depth. Although dislocation pileup models should provide a good explanation of the surface deformation near the fault trace, that explanation may not be adequate at greater distances from the fault trace because approximating the expected horizontally distributed deformation at subcrustal depths by uniform slip concentrated on the fault is not justified.

Instability of total hip replacement: A clinical study and determination of its risk factors.

PubMed

Ezquerra-Herrando, L; Seral-García, B; Quilez, M P; Pérez, M A; Albareda-Albareda, J

2015-01-01

To determine the risk factors associated with prosthetic dislocation and simulate a finite element model to determine the safe range of movement of various inclination and anteversion cup positions. Retrospective Case Control study with 46 dislocated patients from 1994 to 2011. 83 randomly selected patients. Dislocation risk factors described in the literature were collected. A prosthetic model was simulated using finite elements with 28, 32, 36 mm heads, and a 52 mm cup. Acetabular position was 25°, 40°, and 60° tilt and with 0°, 15° and 25° anteversion. In extension of 0° and flexion of 90°, internal and external rotation was applied to analyze the range of movement, maximum resisting moment, and stress distribution in the acetabulum to impingement and dislocation. There was greater dislocation in older patients (p=0.002). Higher dislocation in fractures than in osteoarthritis (p=0.001). Less anteversion in dislocated patients (p=0.043). Longer femoral neck in dislocated patients (p=0.002). Finite element model: lower dislocation when there is more anteversion, tilt and bigger femoral heads. Advanced age and fractures are the major risk factors for dislocation. "Safe zone" of movement for dislocation avoidance is 40°-60° tilt and 15°-25° anteversion. Both the defect and excess of soft tissue tension predispose to dislocation. Bigger femoral heads are more stable. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.

Dislocation Multiplication in the Early Stage of Deformation in Mo Single Crystals

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

Hsiung, L.; Lassila, D.H.

Initial dislocation structure in annealed high-purity Mo single crystals and deformation substructure in a crystal subjected to 1% compression have been examined and studied using transmission electron microscopy (TEM) techniques in order to investigate dislocation multiplication mechanisms in the early stage of plastic deformation. The initial dislocation density is in a range of 10{sup 6} {approx} 10{sup 7} cm{sup -2}, and the dislocation structure is found to contain many grown-in superjogs along dislocation lines. The dislocation density increases to a range of 10{sup 8} {approx} 10{sup 9} cm{sup -2}, and the average jog height is also found to increase aftermore » compressing for a total strain of 1%. It is proposed that the preexisting jogged screw dislocations can act as (multiple) dislocation multiplication sources when deformed under quasi-static conditions. The jog height can increase by stress-induced jog coalescence, which takes place via the lateral migration (drift) of superjogs driven by unbalanced line-tension partials acting on link segments of unequal lengths. The coalescence of superjogs results in an increase of both link length and jog height. Applied shear stress begins to push each link segment to precede dislocation multiplication when link length and jog height are greater than critical lengths. This ''dynamic'' dislocation multiplication source is suggested to be crucial for the dislocation multiplication in the early stage of plastic deformation in Mo.« less

Evaluation of patellar chondromalacia with MR: comparison between T2-weighted FSE SPIR and GE MTC.

PubMed

Macarini, Luca; Perrone, Alessandra; Murrone, Mario; Marini, Stefania; Stefanelli, Michele

2004-09-01

To compare two different MR sequences to tissue signal suppression in the study of patellar cartilage abnormalities. We examined 26 patients with magnetic resonance (MR) imaging: sequences included spectral presaturation with inversion recovery (SPIR), with fat suppression and T2-weighted images, magnetization transfer contrast (MTC) sequences, T1-weighted and T2-weighted spin-echo sequences. All patients underwent conventional knee arthroscopy and in all patients a hyaline cartilage lesion was assessed in three articular zones: the patellar medial facet, the lateral facet and the patellar crista. Was assessed 78 articular facets. The lesions were classified using a standard arthroscopic grading system adapted to MR imaging: normal cartilage that corresponds to the grade 0 according to the Noyes grading system, low grade lesions that correspond to the grade I e IIa and high grade lesions that correspond to grades IIb and III. The arthroscopic results were compared with MR images. We assessed the MR diagnostic accuracy, sensitivity, specificity and MR positive predictive value and negative predictive value of the two sequences taking into consideration total lesions, and high-grade and low grade lesions separately. Twenty-four low grade lesions (16 grade I e 8 grade IIa) and 18 high grade lesions (10 grade IIb e 8 grade III) were diagnosed by arthroscopy. Regarding low grade and high-grade lesions together, the accuracy was 77% for MTC sequences and 90% for SPIR sequences. In identifying low-grade lesions, the sensitivity was 88% for SPIR sequence and 42% for MTC sequences. Specificity for the detection of all lesions was 89% for the SPIR sequences and 94% for the MTC sequences. The SPIR sequence visualised water content abnormalities in degenerating cartilage, which are representative of low-grade lesions. The sensitivity of the sequence enabled us to obtain improved contrast for detecting cartilage surface irregularities. The MTC sequences allowed us to grade high-grade lesions susceptible to surgery and small cartilage defects in the presence of joint fluid. The MTC sequences were insufficient in the diagnosis of early stages of chondromalacia because the suppression of the signal of bonded water reduced the contrast among areas of articular cartilage with different water content. For this reason cartilage oedema and early superficial fibrillation were not identified. In our experience the SPIR sequence proved superior to the MTC sequence in the identification of low grade lesions of the patellar cartilage. The overall value of such sequences in the study of articular pathology also needs to be assessed in the others sites where the articular cartilage is thinner and surfaces more curvilinear.

Unzipping and movement of Lomer-type edge dislocations in Ge/GeSi/Si(0 0 1) heterostructures

NASA Astrophysics Data System (ADS)

Bolkhovityanov, Yu. B.; Deryabin, A. S.; Gutakovskii, A. K.; Sokolov, L. V.

2018-02-01

Edge dislocations in face-centered crystals are formed from two mixed dislocations gliding along intersecting {1 -1 1} planes, forming the so-called Lomer locks. This process, which is called zipping, is energetically beneficial. It is experimentally demonstrated in this paper that a reverse process may occur in Ge/GeSi strained buffer/Si(0 0 1) heterostructures under certain conditions, namely, decoupling of two 60° dislocations that formed the Lomer-type dislocation, i.e., unzipping. It is assumed that the driving force responsible for separation of Lomer dislocations into two 60° dislocations is the strain remaining in the GeSi buffer layer.

Reduction of threading dislocation density in SiGe epilayer on Si (0 0 1) by lateral growth liquid-phase epitaxy

NASA Astrophysics Data System (ADS)

O'Reilly, Andrew J.; Quitoriano, Nathaniel J.

2018-02-01

Si0.973Ge0.027 epilayers were grown on a Si (0 0 1) substrate by a lateral liquid-phase epitaxy (LLPE) technique. The lateral growth mechanism favoured the glide of misfit dislocations and inhibited the nucleation of new dislocations by maintaining the thickness less than the critical thicknesses for dislocation nucleation and greater than the critical thickness for glide. This promoted the formation of an array of long misfit dislocations parallel to the [1 1 0] growth direction and reduced the threading dislocation density to 103 cm-2, two orders of magnitude lower than the seed area with an isotropic misfit dislocation network.

Temporomandibular joint dislocation

PubMed Central

Sharma, Naresh Kumar; Singh, Akhilesh Kumar; Pandey, Arun; Verma, Vishal; Singh, Shreya

2015-01-01

Temporomandibular joint (TMJ) dislocation is an uncommon but debilitating condition of the facial skeleton. The condition may be acute or chronic. Acute TMJ dislocation is common in clinical practice and can be managed easily with manual reduction. Chronic recurrent TMJ dislocation is a challenging situation to manage. In this article, we discuss the comprehensive review of the different treatment modalities in managing TMJ dislocation. PMID:26668447

Density of dislocations in CdHgTe heteroepitaxial structures on GaAs(013) and Si(013) substrates

NASA Astrophysics Data System (ADS)

Sidorov, Yu. G.; Yakushev, M. V.; Varavin, V. S.; Kolesnikov, A. V.; Trukhanov, E. M.; Sabinina, I. V.; Loshkarev, I. D.

2015-11-01

Epitaxial layers of Cd x Hg1- x Te (MCT) on GaAs(013) and Si(013) substrates were grown by molecular beam epitaxy. The introduction of ZnTe and CdTe intermediate layers into the structures made it possible to retain the orientation close to that of the substrate in MCT epitaxial layers despite the large mismatch between the lattice parameters. The structures were investigated using X-ray diffraction and transmission electron microscopy. The dislocation families predominantly removing the mismatch between the lattice parameters were found. Transmission electron microscopy revealed Γ-shaped misfit dislocations (MDs), which facilitated the annihilation of threading dislocations. The angles of rotation of the lattice due to the formation of networks of misfit dislocations were measured. It was shown that the density of threading dislocations in the active region of photodiodes is primarily determined by the network of misfit dislocations formed in the MCT/CdTe heterojunction. A decrease in the density of threading dislocations in the MCT film was achieved by cyclic annealing under conditions of the maximally facilitated nonconservative motion of dislocations. The dislocation density was determined from the etch pits.

Grain size effects on dislocation and twinning mediated plasticity in magnesium

DOE PAGES

Fan, Haidong; Aubry, Sylvie; Arsenlis, Athanasios; ...

2015-09-20

Grain size effects on the competition between dislocation slip and {101¯2} -twinning in magnesium are investigated using discrete dislocation dynamics simulations. These simulations account for dislocation–twin boundary interactions and twin boundary migration through the glide of twinning dislocations. It is shown that twinning deformation exhibits a strong grain size effect; while dislocation mediated slip in untwinned polycrystals displays a weak one. In conclusion, this leads to a critical grain size at 2.7 μm, above which twinning dominates, and below which dislocation slip dominates.

Undisplaced Intraoperative Fracture Presenting as Early Dislocation with Tapered Wedge Stems in Total Hip Arthroplasty - Case Series and Review of Literature

PubMed Central

Reddy, A V Gurava; Eachempati, Krishna Kiran; Mugalur, Aakash; Suchinder, A; Rao, V B N Prasad; Kamurukuru, Nalanda

2017-01-01

Introduction: Periprosthetic fractures and dislocation in the early post-operative period can be disastrous both for the surgeon and the patient. However, undisplaced periprosthetic fractures presenting with dislocation is uncommon. We describe successful management of two cases (one bilateral dislocation and one unilateral dislocation) of undisplaced iatrogenic fractures in total hip arthroplasty (THA) presenting as early dislocation. Case Report: Case 1 was a 45-year-old female with osteoarthritis of hip secondary to developmental dysplasia of the hip with bilateral early nontraumatic dislocation with bilateral identical periprosthetic fracture. It was managed by revision to long stem and encirclage wiring. Case 2 presented with early dislocation in the 2nd week post THA. We found an intertrochanteric fracture intra-operatively with unstable implant. Acetabular component and femoral component revision were done with reconstruction of the greater trochanter. Discussion: These fractures could be occult iatrogenic fractures characteristic of taper wedge stems which presented as early nontraumatic dislocation in the post-operative period. The prosthesis subsidence, loss of muscle tension and change of version might be the factors leading to dislocation. Conclusion: Unrecognized incomplete intraoperative fracture can occur with tapered wedge uncemented stems which can present as a dislocation in the immediate post-operative period. This will require early revision of the femoral component. PMID:29051875

Defect structure of high temperature hydride vapor phase epitaxy-grown epitaxial (0 0 0 1) AlN/sapphire using growth mode modification process

NASA Astrophysics Data System (ADS)

Su, Xujun; Zhang, Jicai; Huang, Jun; Zhang, Jinping; Wang, Jianfeng; Xu, Ke

2017-06-01

Defect structures were investigated by transmission electron microscopy for AlN/sapphire (0 0 0 1) epilayers grown by high temperature hydride vapor phase epitaxy using a growth mode modification process. The defect structures, including threading dislocations, inversion domains, and voids, were analyzed by diffraction contrast, high-resolution imaging, and convergent beam diffraction. AlN film growth was initiated at 1450 °C with high V/III ratio for 8 min. This was followed by low V/III ratio growth for 12 min. The near-interfacial region shows a high density of threading dislocations and inversion domains. Most of these dislocations have Burgers vector b = 1/3〈1 1 2 0〉 and were reduced with the formation of dislocation loops. In the middle range 400 nm < h < 2 μm, dislocations gradually aggregated and reduced to ∼109 cm-2. The inversion domains have a shuttle-like shape with staggered boundaries that deviate by ∼ ±5° from the c axis. Above 2 μm thickness, the film consists of isolated threading dislocations with a total density of 8 × 108 cm-2. Most of threading dislocations are either pure edge or mixed dislocations. The threading dislocation reduction in these films is associated with dislocation loops formation and dislocation aggregation-interaction during island growth with high V/III ratio.

Evolution of the substructure of a novel 12% Cr steel under creep conditions

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

Yadav, Surya Deo, E-mail: surya.yadav@tugraz.at; Kalácska, Szilvia, E-mail: kalacska@metal.elte.hu; Dománková, Mária, E-mail: maria.domankova@stuba.sk

2016-05-15

In this work we study the microstruture evolution of a newly developed 12% Cr martensitic/ferritic steel in as-received condition and after creep at 650 °C under 130 MPa and 80 MPa. The microstructure is described as consisting of mobile dislocations, dipole dislocations, boundary dislocations, precipitates, lath boundaries, block boundaries, packet boundaries and prior austenitic grain boundaries. The material is characterized employing light optical microscopy (LOM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and electron backscatter diffraction (EBSD). TEM is used to characterize the dislocations (mobile + dipole) inside the subgrains and XRD measurements are used tomore » the characterize mobile dislocations. Based on the subgrain boundary misorientations obtained from EBSD measurements, the boundary dislocation density is estimated. The total dislocation density is estimated for the as-received and crept conditions adding the mobile, boundary and dipole dislocation densities. Additionally, the subgrain size is estimated from the EBSD measurements. In this publication we propose the use of three characterization techniques TEM, XRD and EBSD as necessary to characterize all type of dislocations and quantify the total dislocation densty in martensitic/ferritic steels. - Highlights: • Creep properties of a novel 12% Cr steel alloyed with Ta • Experimental characterization of different types of dislocations: mobile, dipole and boundary • Characterization and interpretation of the substructure evolution using unique combination of TEM, XRD and EBSD.« less

Theory of interacting dislocations on cylinders.

PubMed

Amir, Ariel; Paulose, Jayson; Nelson, David R

2013-04-01

We study the mechanics and statistical physics of dislocations interacting on cylinders, motivated by the elongation of rod-shaped bacterial cell walls and cylindrical assemblies of colloidal particles subject to external stresses. The interaction energy and forces between dislocations are solved analytically, and analyzed asymptotically. The results of continuum elastic theory agree well with numerical simulations on finite lattices even for relatively small systems. Isolated dislocations on a cylinder act like grain boundaries. With colloidal crystals in mind, we show that saddle points are created by a Peach-Koehler force on the dislocations in the circumferential direction, causing dislocation pairs to unbind. The thermal nucleation rate of dislocation unbinding is calculated, for an arbitrary mobility tensor and external stress, including the case of a twist-induced Peach-Koehler force along the cylinder axis. Surprisingly rich phenomena arise for dislocations on cylinders, despite their vanishing Gaussian curvature.

Quantitative analysis of dislocation arrangements induced by electromigration in a passivated Al (0.5 wt % Cu) interconnect

NASA Astrophysics Data System (ADS)

Barabash, R. I.; Ice, G. E.; Tamura, N.; Valek, B. C.; Bravman, J. C.; Spolenak, R.; Patel, J. R.

2003-05-01

Electromigration during accelerated testing can induce plastic deformation in apparently undamaged Al interconnect lines as recently revealed by white beam scanning x-ray microdiffraction. In the present article, we provide a first quantitative analysis of the dislocation structure generated in individual micron-sized Al grains during an in situ electromigration experiment. Laue reflections from individual interconnect grains show pronounced streaking during the early stages of electromigration. We demonstrate that the evolution of the dislocation structure during electromigration is highly inhomogeneous and results in the formation of unpaired randomly distributed dislocations as well as geometrically necessary dislocation boundaries. Approximately half of all unpaired dislocations are grouped within the walls. The misorientation created by each boundary and density of unpaired individual dislocations is determined. The origin of the observed plastic deformation is considered in view of the constraints for dislocation arrangements under the applied electric field during electromigration.

Jumper's Knee (Patellar Tendonitis)

MedlinePlus

... knee to move, bend, straighten, provide strength to jump, and stabilize the leg for landing. About Jumper's ... medical professional will ask the person to run, jump, kneel, or squat to determine the level of ...

Structure, ontogeny and evolution of the patellar tendon in emus (Dromaius novaehollandiae) and other palaeognath birds

PubMed Central

Pitsillides, Andrew A.; Hutchinson, John R.

2014-01-01

The patella (kneecap) exhibits multiple evolutionary origins in birds, mammals, and lizards, and is thought to increase the mechanical advantage of the knee extensor muscles. Despite appreciable interest in the specialized anatomy and locomotion of palaeognathous birds (ratites and relatives), the structure, ontogeny and evolution of the patella in these species remains poorly characterized. Within Palaeognathae, the patella has been reported to be either present, absent, or fused with other bones, but it is unclear how much of this variation is real, erroneous or ontogenetic. Clarification of the patella’s form in palaeognaths would provide insight into the early evolution of the patella in birds, in addition to the specialized locomotion of these species. Findings would also provide new character data of use in resolving the controversial evolutionary relationships of palaeognaths. In this study, we examined the gross and histological anatomy of the emu patellar tendon across several age groups from five weeks to 18 months. We combined these results with our observations and those of others regarding the patella in palaeognaths and their outgroups (both extant and extinct), to reconstruct the evolution of the patella in birds. We found no evidence of an ossified patella in emus, but noted its tendon to have a highly unusual morphology comprising large volumes of adipose tissue contained within a collagenous meshwork. The emu patellar tendon also included increasing amounts of a cartilage-like tissue throughout ontogeny. We speculate that the unusual morphology of the patellar tendon in emus results from assimilation of a peri-articular fat pad, and metaplastic formation of cartilage, both potentially as adaptations to increasing tendon load. We corroborate previous observations of a ‘double patella’ in ostriches, but in contrast to some assertions, we find independent (i.e., unfused) ossified patellae in kiwis and tinamous. Our reconstructions suggest a single evolutionary origin of the patella in birds and that the ancestral patella is likely to have been a composite structure comprising a small ossified portion, lost by some species (e.g., emus, moa) but expanded in others (e.g., ostriches). PMID:25551026

Femoral press-fit fixation in ACL reconstruction using bone-patellar tendon-bone autograft: results at 15 years follow-up.

PubMed

Widuchowski, Wojciech; Widuchowska, Malgorzata; Koczy, Bogdan; Dragan, Szymon; Czamara, Andrzej; Tomaszewski, Wieslaw; Widuchowski, Jerzy

2012-06-27

If anterior cruciate ligament (ACL) reconstruction is to be performed, decision regarding graft choice and its fixation remains one of the most controversial. Multiple techniques for ACL reconstruction are available. To avoid disadvantages related to fixation devices, a hardware-free, press-fit ACL reconstruction technique was developed. The aim of this study was to evaluate clinical outcome and osteoarthritis progression in long term after ACL reconstruction with central third patellar-tendon autograft fixed to femur by press-fit technique. Fifty two patients met inclusion/excusion criteria for this study. The patients were assessed preoperatively and at 15 years after surgery with International Knee Documentation Committee Knee Ligament Evaluation Form, Lysholm knee score, Tegner activity scale and radiographs. Good overall clinical outcomes and self-reported assessments were documented, and remained good at 15 years. The mean Lysholm and Tegner scores improved from 59.7 ± 18.5 and 4.2 ± 1.0 preoperatively to 86.4 ± 5.6 (p = 0.004) and 6.9 ± 1.4 (p = 0.005) respectively at follow-up. The IKDC subjective score improved from 60.1 ± 9.2 to 80.2 ± 8.1 (p = 0.003). According to IKDC objective score, 75% of patients had normal or nearly normal knee joints at follow-up. Grade 0 or 1 results were seen in 85% of patients on laxity testing. Degenerative changes were found in 67% of patients. There was no correlation between arthritic changes and stability of knee and subjective evaluation (p > 0.05). ACL reconstruction with patellar tendon autograft fixed to femur with press-fit technique allows to achieve good self-reported assessments and clinical ligament evaluation up to 15 years. Advantages of the bone-patellar-tendon-bone (BPTB) press-fit fixation include unlimited bone-to-bone healing, cost effectiveness, avoidance of disadvantages associated with hardware, and ease for revision surgery. BPTB femoral press-fit fixation technique can be safely applied in clinical practice and enables patients to return to preinjury activities including high-risk sports.

Management of displaced inferior patellar pole fractures with modified tension band technique combined with cable cerclage using Cable Grip System.

PubMed

Yang, Xu; Wu, Qinfen; Lai, Chin-Hui; Wang, Xin

2017-10-01

We present a modified tension band technique combined with cable cerclage using Cable Grip System for the treatment of displaced inferior patellar pole fractures and report the knee functional outcome. The patients who had had operative treatment of a displaced inferior patellar pole fracture (AO/OTA 34-A1) between December 2013 and December 2015 were studied retrospectively. Eleven consecutive patients had had open reduction and internal fixation with the modified technique using Cable Grip System, of whom, five males and six females with an average age of 60.9 years (range, 29-81 years). All fractures occurred from direct fall onto the knee. The average time from injury to surgery was 6.1days (range, 2-12days). The range of motion (ROM) was measured in degrees by goniometry at postoperative intervals of 1, 2, 4, 12, and 48 weeks; Knee function was evaluated using the Rasmussen scores at final follow-up. No patients had nonunion, loss of reduction, migration of wire, irritation from the implant and fixation breakage during the follow-up period. Recovery of ROM was achieved at 12 weeks, with the average ROM at 1 week was 72° (range, 65°-78°), 86.4° (range, 78°-92°) at 2 weeks, 115.5° (range, 103°-122°) at 4 weeks, 129.6° (range, 122°-133°) at 12 weeks, 134.5° (range, 129°-139°) at 48 weeks after the operation. Concerning the knee function outcome assessment, all patients showed excellent results at final follow-up. The average Rasmussen scores was 27.9 out of 30 (range, 27-29). The modified tension band technique combined with cable cerclage using Cable Grip System for displaced inferior patellar pole fractures can provide stable fixation with excellent results in knee function, allows for immediate mobilization and early weight-bearing, which is a simple and valuable technique in routine clinical practice. Copyright © 2017 Elsevier Ltd. All rights reserved.

Study protocol: a double blind randomised control trial of high volume image guided injections in Achilles and patellar tendinopathy in a young active population.

PubMed

Barker-Davies, Robert M; Nicol, Alastair; McCurdie, I; Watson, James; Baker, Polly; Wheeler, Patrick; Fong, Daniel; Lewis, Mark; Bennett, Alexander N

2017-05-22

Chronic tendinopathy is a significant problem particularly in active populations limiting sporting and occupational performance. The prevalence of patellar tendinopathy in some sports is near 50% and the incidence of lower limb tendinopathy is 1.4% p.a. in the UK Military. Management includes isometric, eccentric, heavy slow resistance exercises and extracorporeal shockwave therapy (ESWT). Often these treatments are inadequate yet there is no good evidence for injection therapies and success rates from surgery can be as low as 50%. High Volume Image Guided Injection (HVIGI) proposes to strip away the neovascularity and disrupt the nerve ingrowth seen in chronic cases and has shown promising results in case series. This study aims to investigate the efficacy of HVIGI in a randomised controlled trial (RCT). RCT comparing 40ml HVIGI, with or without corticosteroid, with a 3ml local anaesthetic sham-control injection. Ninety-six participants will be recruited. male, 18-55 years old, chronic Achilles or patellar tendinopathy of at least 6 months, failed conservative management including ESWT, and Ultrasound (US) evidence of neovascularisation, tendon thickening and echogenic changes. Outcome measures will be recorded at baseline, 6 weeks, 3, 6 and 12 months. Primary outcome measures include The Victoria Institute of Sport Assessments for Achilles and patellar tendinopathy (VISA-A and VISA-P) and VAS pain. Secondary outcome measures include Modified Ohberg score, maximum tendon diameter and assessment of hypoechoic appearance on US, and Functional Activity Assessment. Despite previous interventional trials and reviews there is still insufficient evidence to guide injectable therapy for chronic tendinopathy that has failed conservative treatment. The scant evidence available suggests HVIGI has the greatest potential however there is no level one RCT evidence to support this. Investigating the efficacy of HVIGI against control in a RCT and separating the effect of HVIGI and corticosteroid will add high level evidence to the management of chronic tendinopathy resistant to conservative treatment. EudraCT: 2015-003587-36 3 Dec 2015.

Clinical results after ultrasound-guided intratissue percutaneous electrolysis (EPI®) and eccentric exercise in the treatment of patellar tendinopathy.

PubMed

Abat, F; Gelber, P E; Polidori, F; Monllau, J C; Sanchez-Ibañez, J M

2015-04-01

To investigate the outcome of ultrasound (US)-guided intratissue percutaneous electrolysis (EPI(®)) and eccentric exercise in the treatment of patellar tendinopathy during a long-term follow-up. Forty patients with patellar tendinopathy were prospectively evaluated over a 10-year follow-up period. Pain and function were evaluated before treatment, at 3 months and at 2, 5 and 10 years using the Victorian Institute of Sport Assessment-Patella (VISA-P) score, the Tegner score and Blazina's classification. According to VISA-P score at baseline, patients were also dichotomized into Group 1 (<50 points) and Group 2 (≥50 points). There were 21 patients in Group 1 and 19 in Group 2. Patient satisfaction was measured according to the Roles and Maudsley score. The VISA-P score improved globally by 41.2 points (p < 0.01) after a mean 4.1 procedures. In Group 1, VISA-P score improved from 33.1 ± 13 to 78.9 ± 14.4 at 3-month and to 88.8 ± 10.1 at 10-year follow-up (p < 0.001). In Group 2, VISA-P score improved from 69.3 ± 10.5 to 84.9 ± 9 at 3-month and to 96.0 ± 4.3 at 10-year follow-up (p < 0.001). After 10 years, 91.2 % of the patients had a VISA-P score >80 points. The same level (80 % of patients) or the Tegner score at no more than one level lower (20 % of patients) was restored, and 97.5 % of the patients were satisfied with the procedure. Treatment with the US-guided EPI(®) technique and eccentric exercises in patellar tendinopathy resulted in a great improvement in knee function and a rapid return to the previous level of activity after few sessions. The procedure has proved to be safe with no recurrences on a long-term basis. Therapeutic study, Level IV.

Low-dislocation-density epitatial layers grown by defect filtering by self-assembled layers of spheres

DOEpatents

Wang, George T.; Li, Qiming

2013-04-23

A method for growing low-dislocation-density material atop a layer of the material with an initially higher dislocation density using a monolayer of spheroidal particles to bend and redirect or directly block vertically propagating threading dislocations, thereby enabling growth and coalescence to form a very-low-dislocation-density surface of the material, and the structures made by this method.

Effects of dislocations on polycrystal anelasticity

NASA Astrophysics Data System (ADS)

Sasaki, Y.; Takei, Y.; McCarthy, C.; Suzuki, A.

2017-12-01

Effects of dislocations on the seismic velocity and attenuation have been poorly understood, because only a few experimental studies have been performed [Guéguen et al., 1989; Farla et al., 2012]. By using organic borneol as a rock analogue, we measured dislocation-induced anelasticity accurately over a broad frequency range. We first measured the flow law of borneol aggregates by uniaxial compression tests under a confining pressure of 0.8 MPa. A transition from diffusion creep (n = 1) to dislocation creep (n = 5) was captured at about σ = 1 MPa (40°C-50°C). After deforming in the dislocation creep regime, sample microstructure showed irregular grain shape consistent with grain boundary migration. Next, we conducted three creep tests at σ = 0.27 MPa (diffusion creep regime), σ = 1.3 MPa and σ = 1.9 MPa (dislocation creep regime) on the same sample in increasing order, and measured Young's modulus E and attenuation Q-1 after each creep test by forced oscillation tests. The results show that as σ increased, E decreased and Q-1 increased. These changes induced by dislocations, however, almost fully recovered during the forced oscillation tests performed for about two weeks under a small stress (σ = 0.27 MPa) due to the dislocation recovery (annihilation). In order to constrain the time scale of the dislocation-induced anelastic relaxation, we further measured Young's modulus E at ultrasonic frequency before and after the dislocation creep and found that E at 106 Hz is not influenced by dislocations. Because E at 100 Hz is reduced by dislocations by 10%, the dislocation-induced anelastic relaxation occurs mostly between 102-106 Hz which is at a higher frequency than grain-boundary-induced anelasticity. To avoid dislocation recovery during the anelasticity measurement, we are now trying to perform an in-situ measurement of anelasticity while simultaneously deforming under a high stress associated with dislocation creep. The combination of persistent creep stress with small amplitude perturbations is similar to a seismic wave traveling through a region of active tectonic deformation.

Atomistic simulations of dislocation pileup: Grain boundaries interaction

DOE PAGES

Wang, Jian

2015-05-27

Here, using molecular dynamics (MD) simulations, we studied the dislocation pileup–grain boundary (GB) interactions. Two Σ11 asymmetrical tilt grain boundaries in Al are studied to explore the influence of orientation relationship and interface structure on dislocation activities at grain boundaries. To mimic the reality of a dislocation pileup in a coarse-grained polycrystalline, we optimized the dislocation population in MD simulations and developed a predict-correct method to create a dislocation pileup in MD simulations. MD simulations explored several kinetic processes of dislocations–GB reactions: grain boundary sliding, grain boundary migration, slip transmission, dislocation reflection, reconstruction of grain boundary, and the correlation ofmore » these kinetic processes with the available slip systems across the GB and atomic structures of the GB.« less

Split and sealing of dislocated pipes at the front of a growing crystal

NASA Astrophysics Data System (ADS)

Gutkin, M. Yu.; Sheinerman, A. G.

2004-07-01

A model is suggested for the split of dislocated pipes at the front a growing crystal. Within the model, the pipe split occurs through the generation of a dislocation semi-loop at the pipe and crystal surfaces and its subsequent expansion into the crystal interior. The strain energy of such a dislocation semi-loop as well as the stress field of a dislocated pipe perpendicular to a flat crystal surface are calculated. The parameter regions are determined at which the expansion of the dislocation semi-loop is energetically favorable and, thus, the pipe split becomes irreversible. A mechanism is proposed for the formation of a stable semi-loop resulting in the split and possible subsequent overgrowth of the dislocated pipe.

Dislocation-Twin Boundary Interactions Induced Nanocrystalline via SPD Processing in Bulk Metals

NASA Astrophysics Data System (ADS)

Zhang, Fucheng; Feng, Xiaoyong; Yang, Zhinan; Kang, Jie; Wang, Tiansheng

2015-03-01

This report investigated dislocation-twin boundary (TB) interactions that cause the TB to disappear and turn into a high-angle grain boundary (GB). The evolution of the microstructural characteristics of Hadfield steel was shown as a function of severe plastic deformation processing time. Sessile Frank partial dislocations and/or sessile unit dislocations were formed on the TB through possible dislocation reactions. These reactions induced atomic steps on the TB and led to the accumulation of gliding dislocations at the TB, which resulted in the transition from coherent TB to incoherent GB. The factors that affect these interactions were described, and a physical model was established to explain in detail the feasible dislocation reactions at the TB.

Dislocation-twin boundary interactions induced nanocrystalline via SPD processing in bulk metals.

PubMed

Zhang, Fucheng; Feng, Xiaoyong; Yang, Zhinan; Kang, Jie; Wang, Tiansheng

2015-03-11

This report investigated dislocation-twin boundary (TB) interactions that cause the TB to disappear and turn into a high-angle grain boundary (GB). The evolution of the microstructural characteristics of Hadfield steel was shown as a function of severe plastic deformation processing time. Sessile Frank partial dislocations and/or sessile unit dislocations were formed on the TB through possible dislocation reactions. These reactions induced atomic steps on the TB and led to the accumulation of gliding dislocations at the TB, which resulted in the transition from coherent TB to incoherent GB. The factors that affect these interactions were described, and a physical model was established to explain in detail the feasible dislocation reactions at the TB.

Investigation of threading dislocation blocking in strained-layer InGaAs/GaAs heterostructures using scanning cathodoluminescence microscopy

NASA Astrophysics Data System (ADS)

Russell, J. J.; Zou, J.; Moon, A. R.; Cockayne, D. J. H.

2000-08-01

Threading dislocation glide relieves strain in strained-layer heterostructures by increasing the total length of interface misfit dislocations. The blocking theory proposed by Freund [J. Appl. Phys. 68, 2073 (1990)] predicts the thickness above which gliding threading dislocations are able to overcome the resistance force produced by existing orthogonal misfit dislocations. A set of wedge-shaped samples of InxGa1-xAs/GaAs (x=0.04) strained-layer heterostructures was grown using molecular-beam epitaxy in order to test the theory of dislocation blocking over a range of thicknesses within one sample. Scanning cathodoluminescence microscopy techniques were used to image the misfit dislocations. The cathodoluminescence results confirm the model proposed by Freund.

Bilateral spontaneous crystalline lens dislocation to the anterior chamber: a case report.

PubMed

Jovanović, Milos

2013-01-01

There are various reasons for the lens dislocation. Spontaneous dislocation of a clear lens is extremely rare, especially its dislocation to the anterior chamber. The author presents a case of spontaneous clear lens dislocation to the anterior chamber in both eyes in a patient without the history of any trauma. Dislocation occurred spontaneously, first in the left eye, along with a sudden decrease of vision. The ophthalmologist found a clear lens in the anterior chamber, without any sign of an elevated intraocular pressure, as should have been expected. The dislocated lens was removed surgically (intracapsular extraction) with the preventive basal iridectomy. Two years later, the same happened in the right eye: clear lens moved spontaneously to the anterior chamber, with a decrease of vision, but again without any rise of intraocular pressure and/or any pain. Intracapsular extraction of the lens with basal iridectomy was done again. The presented case demonstrates that spontaneous dislocation of the transparent lens to the eye anterior chamber can occur in both eyes at different time intervals. We suggest the removal of dislocated lens in the anterior chamber by the intracapsular extraction.

Fast Fourier transform discrete dislocation dynamics

NASA Astrophysics Data System (ADS)

Graham, J. T.; Rollett, A. D.; LeSar, R.

2016-12-01

Discrete dislocation dynamics simulations have been generally limited to modeling systems described by isotropic elasticity. Effects of anisotropy on dislocation interactions, which can be quite large, have generally been ignored because of the computational expense involved when including anisotropic elasticity. We present a different formalism of dislocation dynamics in which the dislocations are represented by the deformation tensor, which is a direct measure of the slip in the lattice caused by the dislocations and can be considered as an eigenstrain. The stresses arising from the dislocations are calculated with a fast Fourier transform (FFT) method, from which the forces are determined and the equations of motion are solved. Use of the FFTs means that the stress field is only available at the grid points, which requires some adjustments/regularizations to be made to the representation of the dislocations and the calculation of the force on individual segments, as is discussed hereinafter. A notable advantage of this approach is that there is no computational penalty for including anisotropic elasticity. We review the method and apply it in a simple dislocation dynamics calculation.

Identical activation volumes of dislocation mobility in the [100](010) and [001](010) slip systems in natural olivine

NASA Astrophysics Data System (ADS)

Wang, Lin; Blaha, Stephan; Kawazoe, Takaaki; Miyajima, Nobuyoshi; Katsura, Tomoo

2017-03-01

Dislocation recovery experiments were performed on predeformed olivine single crystals at pressures of 2, 7 and 12 GPa and a constant temperature of 1650 K to determine the pressure dependence of the annihilation rate constants for [100](010) edge dislocation (a dislocation) and [001](010) screw dislocation (c dislocation). The constants of both types of dislocations are comparable within 0.3 orders of magnitude. The activation volumes of a and c dislocations are small and identical within error: 2.7 ± 0.2 and 2.5 ± 0.9 cm3/mol, respectively. These values are slightly larger and smaller than those of Si lattice and grain-boundary diffusions in olivine, respectively. The small and identical activation volumes for the a and c dislocations suggest that the pressure-induced fabric transition is unlikely in the asthenosphere. The decrease in seismic anisotropy with depth down in the asthenosphere may be caused by the fabric transition from A type or B type to AG type with decreasing stress with depth.

Three-dimensional interaction and movements of various dislocations in anisotropic bicrystals with semicoherent interfaces

NASA Astrophysics Data System (ADS)

Vattré, A.; Pan, E.

2018-07-01

Lattice dislocation interactions with semicoherent interfaces are investigated by means of anisotropic field solutions in metallic homo- and hetero-structures. The present framework is based on the mathematically elegant and computationally powerful Stroh formalism, combining further with the Fourier integral and series transforms, which cover different shapes and dimensions of various extrinsic and intrinsic dislocations. Two-dimensional equi-spaced arrays of straight lattice dislocations and finite arrangements of piled-up dislocations as well as any polygonal and elliptical dislocation loops in three dimensions are considered using a superposition scheme. Self, image and Peach-Koehler forces are derived to compute the equilibrium dislocation positions in pile-ups, including the internal structures and energetics of the interfacial dislocation networks. For illustration, the effects due to the elastic and misfit mismatches are discussed in the pure misfit Au/Cu and heterophase Cu/Nb systems, while discrepancies resulting from the approximation of isotropic elasticity are clearly exhibited. These numerical examples not only feature and enhance the existing works in anisotropic bimaterials, but also promote a novel opportunity of analyzing the equilibrium shapes of planar glide dislocation loops at nanoscale.

Validation of the German version of the Kujala score in patients with patellofemoral instability: a prospective multi-centre study.

PubMed

Dammerer, D; Liebensteiner, M C; Kujala, U M; Emmanuel, K; Kopf, S; Dirisamer, F; Giesinger, J M

2018-04-01

The Kujala score is the most frequently used questionnaire for patellofemoral disorders like pain, instability or osteoarthritis. Unfortunately, we are not aware of a validated German version of the Kujala score. The aim of our study was the translation and linguistic validation of the Kujala score in German-speaking patients with patella instability and the assessment of its measurement characteristics. The German Kujala score was developed in several steps of translation. In addition to healthy controls, the Kujala German was assessed in consecutive patients undergoing reconstruction of the medial patellofemoral ligament for recurrent patellar dislocations. Pre-op, 6 and 12 months postop the patients completed the Kujala German score, the KOOS, the Lysholm score, a VAS Pain, and the SF-12v2 scores. In addition, there was a Kujala German Score retest preop after a 1-week interval. We found high reliability in terms of internal consistency for the Kujala score (Cronbach's alpha = 0.87). Convergent validity with the KOOS (symptom r = 0.65, pain r = 0.78, ADL r = 0.74, sports/recreation r = 0.84, quality of life r = 0.70), the Lysholm score (r = 0.88) and the SF-12 physical component summary score (r = 0.79) and VAS pain (r = - 0.71) was also very high. Discriminant validity in terms of correlation with the SF-12 mental component summary Score was satisfactory (r = 0.14). In conclusion, the German version of the Kujala score proved to be a reliable and valid instrument in the setting of a typical patellofemoral disease treated with a standard patellofemoral procedure.

[Diagnostic significance of "bay sign" of medial meniscus under arthroscope in medial collateral ligament rupture of knee].

PubMed

Zhang, Wentao; Zhang, Xintao; Huang, Wei

2012-03-01

When knee medial collateral ligament (MCL) rupture, the upper surface of medial meniscus is exposed totally, like the gulf panoramic, which is called "panoramic views of the bay sign" or the "bay sign". To investigate the reliability and significance of the "bay sign" in diagnosis of knee MCL rupture under arthroscope. Between March 2007 and March 2011, 127 patients with knees injuries were divided into the observation group (n = 59) and control group (n = 68) based on the MRI results. In the observation group, 59 patients had MCL rupture by MRI, including 12 cases of MCL injury alone, 16 cases of MCL injury with lateral meniscus torn, 27 cases of MCL injury with anterior cruciate ligament (ACL) injury, 3 cases of MCL injury with ACL and posterior cruciate ligament (PCL) injury, and 1 case of MCL injury with patellar dislocation; there were 38 males and 21 females with an average age of 23.2 years (range, 16-39 years). In the control group, 68 patients had no MCL rupture by MRI, including 38 cases of ACL injury, 4 cases of ACL and PCL injury, and 26 cases of ACL and lateral meniscus injury; there were 45 males and 23 females with an average age of 31.8 years (range, 25-49 years). The "bay sign" was observed under arthroscope in 2 groups before and after operation. The positive "bay sign" was seen under arthroscope in the patients of the observation group before MCL repair; the "bay sign" disappeared after repair. No "bay sign" was seen in patients of the control group before and after ACL reconstruction. The "bay sign" is a reliable diagnostic evidence of MCL injury. It can be used as a basis to judge the success of MCL reconstruction during operation.

Proceedings of the International Symposium on the Structure and Properties of Dislocations in Semiconductors (6th) held in Oxford (England) 5-8 April 1989: Structure and Properties of Dislocations in Semiconductors 1989

DTIC Science & Technology

1989-04-08

now good experimental data on the effects of impurities, including locking by non-electrical xii Preface impurities, and the effect of electrically... locks which result from the interaction of the gliding dislocations. As a matter of fact, these dislocation configurations look similar to those...loop on the go° partial. Structure of grain boundaries and dislocations 3 2.2. Lomer-Cottrell lock : a/2>. Two 60’ dislocations can react and give

Debye screening of dislocations.

PubMed

Groma, I; Györgyi, G; Kocsis, B

2006-04-28

Debye-like screening by edge dislocations of some externally given stress is studied by means of a variational approach to coarse grained field theory. Explicitly given are the force field and the induced geometrically necessary dislocation (GND) distribution, in the special case of a single glide axis in 2D, for (i) a single edge dislocation and (ii) a dislocation wall. Numerical simulation demonstrates that the correlation in relaxed dislocation configurations is in good agreement with the induced GND in case (i). Furthermore, the result (ii) well predicts the experimentally observed decay length for the GND developing close to grain boundaries.

Te homogeneous precipitation in Ge dislocation loop vicinity

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

Perrin Toinin, J.; Portavoce, A., E-mail: alain.portavoce@im2np.fr; Texier, M.

2016-06-06

High resolution microscopies were used to study the interactions of Te atoms with Ge dislocation loops, after a standard n-type doping process in Ge. Te atoms neither segregate nor precipitate on dislocation loops, but form Te-Ge clusters at the same depth as dislocation loops, in contradiction with usual dopant behavior and thermodynamic expectations. Atomistic kinetic Monte Carlo simulations show that Te atoms are repulsed from dislocation loops due to elastic interactions, promoting homogeneous Te-Ge nucleation between dislocation loops. This phenomenon is enhanced by coulombic interactions between activated Te{sup 2+} or Te{sup 1+} ions.

Study of the dislocation contribution to the internal friction background of gold

NASA Astrophysics Data System (ADS)

Baur, J.; Benoit, W.

1987-04-01

The dislocation contribution to the internal friction (IF) background is studied in annealed gold samples containing various dilute concentrations of platinum impurities. The measurements are performed in the kHz frequency range in order to determine the loss mechanism responsible for the high IF background observed at these low frequencies. To this end, the IF background was systematically measured as a function of frequency, vibration amplitude, temperature, and impurity concentration. The experimental results show that the high dislocation contribution observed in annealed samples is strain-amplitude independent for amplitudes in the range 10-7 to 2×10-6, but rapidly decreases for amplitudes smaller than 10-7. In particular, the dislocation contribution tends to zero when the strain amplitude tends to zero. Furthermore, this contribution is frequency independent. These observations demonstrate that the dislocation contribution cannot be explained by relaxations. In particular, this contribution cannot be attributed to a viscous damping of the dislocation motion. On the contrary, the experiments show that the IF background due to dislocations must be explained by hysteretic and athermal motions of dislocations interacting with point defects. However, these hysteretic motions are not due to breakaway of dislocations from pinning points distributed along their length. The experimental results can be explained by the presence of point defects close to the dislocations, but not on them. The mechanical energy loss is attributed to hysteretic motions of dislocations between potential minima created by point defects.

Dislocation substructure of mantle-derived olivine as revealed by selective chemical etching and transmission electron microscopy

USGS Publications Warehouse

Kirby, S.H.; Wegner, M.W.

1978-01-01

Cleaved and mechanically polished surfaces of olivine from peridotite xenoliths from San Carlos, Arizona, were chemically etched using the techniques of Wegner and Christie (1974). Dislocation etch pits are produced on all surface orientations and they tend to be preferentially aligned along the traces of subgrain boundaries, which are approximately parallel to (100), (010), and (001). Shallow channels were also produced on (010) surfaces and represent dislocations near the surface that are etched out along their lengths. The dislocation etch channel loops are often concentric, and emanate from (100) subgrain boundaries, which suggests that dislocation sources are in the boundaries. Data on subgrain misorientation and dislocation line orientation and arguments based on subgrain boundary energy minimization are used to characterize the dislocation structures of the subgrain boundaries. (010) subgrain boundaries are of the twist type, composed of networks of [100] and [001] screw dislocations. Both (100) and (001) subgrain boundaries are tilt walls composed of arrays of edge dislocation with Burgers vectors b=[100] and [001], respectively. The inferred slip systems are {001} ???100???, {100} ???001???, and {010} ???100??? in order of diminishing importance. Exploratory transmission electron microscopy is in accord with these identifications. The flow stresses associated with the development of the subgrain structure are estimated from the densities of free dislocations and from the subgrain dimensions. Inferred stresses range from 35 to 75 bars using the free dislocation densities and 20 to 100 bars using the subgrain sizes. ?? 1978 Springer-Verlag.

Prediction of dislocation generation during Bridgman growth of GaAs crystals

NASA Technical Reports Server (NTRS)

Tsai, C. T.; Yao, M. W.; Chait, Arnon

1992-01-01

Dislocation densities are generated in GaAs single crystals due to the excessive thermal stresses induced by temperature variations during growth. A viscoplastic material model for GaAs, which takes into account the movement and multiplication of dislocations in the plastic deformation, is developed according to Haasen's theory. The dislocation density is expressed as an internal state variable in this dynamic viscoplastic model. The deformation process is a nonlinear function of stress, strain rate, dislocation density and temperature. The dislocation density in the GaAs crystal during vertical Bridgman growth is calculated using a nonlinear finite element model. The dislocation multiplication in GaAs crystals for several temperature fields obtained from thermal modeling of both the GTE GaAs experimental data and artificially designed data are investigated.

Prediction of dislocation generation during Bridgman growth of GaAs crystals

NASA Astrophysics Data System (ADS)

Tsai, C. T.; Yao, M. W.; Chait, Arnon

1992-11-01

Dislocation densities are generated in GaAs single crystals due to the excessive thermal stresses induced by temperature variations during growth. A viscoplastic material model for GaAs, which takes into account the movement and multiplication of dislocations in the plastic deformation, is developed according to Haasen's theory. The dislocation density is expressed as an internal state variable in this dynamic viscoplastic model. The deformation process is a nonlinear function of stress, strain rate, dislocation density and temperature. The dislocation density in the GaAs crystal during vertical Bridgman growth is calculated using a nonlinear finite element model. The dislocation multiplication in GaAs crystals for several temperature fields obtained from thermal modeling of both the GTE GaAs experimental data and artificially designed data are investigated.

Movement of basal plane dislocations in GaN during electron beam irradiation

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

Yakimov, E. B.; National University of Science and Technology MISiS, Leninskiy pr. 4, Moscow 119049; Vergeles, P. S.

The movement of basal plane segments of dislocations in low-dislocation-density GaN films grown by epitaxial lateral overgrowth as a result of irradiation with the probing beam of a scanning electron microscope was detected by means of electron beam induced current. Only a small fraction of the basal plane dislocations was susceptible to such changes and the movement was limited to relatively short distances. The effect is explained by the radiation enhanced dislocation glide for dislocations pinned by two different types of pinning sites: a low-activation-energy site and a high-activation-energy site. Only dislocation segments pinned by the former sites can bemore » moved by irradiation and only until they meet the latter pinning sites.« less

Jumper's Knee (Patellar Tendonitis) (For Parents)

MedlinePlus

... knee to move, bend, straighten, provide strength to jump, and stabilize the leg for landing. About Jumper's ... medical professional will ask the patient to run, jump, kneel, or squat to determine the level of ...

Patellar Tendinitis

MedlinePlus

... your shinbone (tibia). Initially, you may only feel pain in your knee as you begin physical activity or just after ... a chair. When to see a doctor For knee pain, try self-care measures first, such as icing ...

Clinical Applications of Platelet-Rich Plasma in Patellar Tendinopathy

PubMed Central

Jeong, D. U.; Lee, C.-R.; Lee, J. H.; Pak, J.; Kang, L.-W.; Jeong, B. C.

2014-01-01

Platelet-rich plasma (PRP), a blood derivative with high concentrations of platelets, has been found to have high levels of autologous growth factors (GFs), such as transforming growth factor-β (TGF-β), platelet-derived growth factor (PDGF), fibroblastic growth factor (FGF), vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF). These GFs and other biological active proteins of PRP can promote tissue healing through the regulation of fibrosis and angiogenesis. Moreover, PRP is considered to be safe due to its autologous nature and long-term usage without any reported major complications. Therefore, PRP therapy could be an option in treating overused tendon damage such as chronic tendinopathy. Here, we present a systematic review highlighting the clinical effectiveness of PRP injection therapy in patellar tendinopathy, which is a major cause of athletes to retire from their respective careers. PMID:25136568

Patellar segmentation from 3D magnetic resonance images using guided recursive ray-tracing for edge pattern detection

NASA Astrophysics Data System (ADS)

Cheng, Ruida; Jackson, Jennifer N.; McCreedy, Evan S.; Gandler, William; Eijkenboom, J. J. F. A.; van Middelkoop, M.; McAuliffe, Matthew J.; Sheehan, Frances T.

2016-03-01

The paper presents an automatic segmentation methodology for the patellar bone, based on 3D gradient recalled echo and gradient recalled echo with fat suppression magnetic resonance images. Constricted search space outlines are incorporated into recursive ray-tracing to segment the outer cortical bone. A statistical analysis based on the dependence of information in adjacent slices is used to limit the search in each image to between an outer and inner search region. A section based recursive ray-tracing mechanism is used to skip inner noise regions and detect the edge boundary. The proposed method achieves higher segmentation accuracy (0.23mm) than the current state-of-the-art methods with the average dice similarity coefficient of 96.0% (SD 1.3%) agreement between the auto-segmentation and ground truth surfaces.

Treatment of transverse patellar fractures: a comparison between metallic and non-metallic implants.

PubMed

Heusinkveld, Maarten H G; den Hamer, Anniek; Traa, Willeke A; Oomen, Pim J A; Maffulli, Nicola

2013-01-01

Several methods of transverse patellar fixation have been described. This study compares the clinical outcome and the occurrence of complications of various fixation methods. The databases PubMed, Web of Science, Science Direct, Google Scholar and Google were searched. A direct comparison between fixation techniques using mixed or non-metallic implants and metallic K-wire and tension band fixation shows no significant difference in clinical outcome between both groups. Additionally, studies reporting novel operation techniques show good clinical results. Studies describing the treatment of patients using non-metallic or mixed implants are fewer compared with those using metallic fixation. A large variety of clinical scoring systems were used for assessing the results of treatment, which makes direct comparison difficult. More data of fracture treatment using non-metallic or mixed implants is needed to achieve a more balanced comparison.

The medial patellofemoral complex.

PubMed

Loeb, Alexander E; Tanaka, Miho J

2018-06-01

The purpose of this review is to describe the current understanding of the medial patellofemoral complex, including recent anatomic advances, evaluation of indications for reconstruction with concomitant pathology, and surgical reconstruction techniques. Recent advances in our understanding of MPFC anatomy have found that there are fibers that insert onto the deep quadriceps tendon as well as the patella, thus earning the name "medial patellofemoral complex" to allow for the variability in its anatomy. In MPFC reconstruction, anatomic origin and insertion points and appropriate graft length are critical to prevent overconstraint of the patellofemoral joint. The MPFC is a crucial soft tissue checkrein to lateral patellar translation, and its repair or reconstruction results in good restoration of patellofemoral stability. As our understanding of MPFC anatomy evolves, further studies are needed to apply its relevance in kinematics and surgical applications to its role in maintaining patellar stability.

An automatic bone segmentation method based on anatomical structure for the knee joint in MDCT image.

PubMed

Uozumi, Y; Nagamune, K

2013-01-01

The purpose of this study is to propose an automatic segmentation about each bone (the femur, the tibia, the patellar, and fibular) of the knee in MDCT image. The proposed method was applied for six patients (Age 33 ± 13, four males/tew females). The proposed method segmented the knee joint into each bone by using anatomical structure for the knee joint. The experiments calculate matching rate of the manual and the proposed method for evaluating it. As a result, The matching rate of the femur, the tibia, the patellar, and fibula were 95.84 ± 0.57%, 94.12 ± 1.01%, 94.49 ± 0.83%, 86.37 ± 4.28%, respectively. This study concluded that the proposed method is enough to segment the knee bones.

Revision of anterior cruciate ligament reconstruction with allografts in patients younger than 40 years old: a 2 to 4 year results.

PubMed

Pascual-Garrido, Cecilia; Carbo, L; Makino, A

2014-05-01

The purpose of this study is first to report the outcomes, at 4 years follow-up, in revision ACL surgery using allografts in patients younger than 40 years old, and then compared soft tissue allografts to bone tendon allografts. This retrospective study included 47 patients who underwent ACL revision surgery with fresh-frozen allografts. Patellar tendon allograft or tibialis anterior allograft was used. Twenty-seven patients undergoing ACL revision with patellar tendon allograft were compared retrospectively with twenty-two patients undergoing the same procedure with soft tissue tibialis anterior allograft. Lysholm, IKDC, and KT-1000 values were obtained preoperatively and postoperatively. The average patient follow-up was 4.6 years (±2.5). The mean age at time of the revision was 34 years old (±6.3). Overall, patients reported the overall condition of their knee as excellent or good in 85% of the patients (10 excellent, 33 good). Based on their experience, 85% would have the surgery again if they had the same problem in the other knee. Both subgroups experienced significant improvement in Lysholm, IKDC, and KT-1000 values, with no difference found between groups at final follow-up. Revision ACL with allografts has excellent and good results in 85% of patients younger than 40 years old. No statistical difference was seen between soft tissue (tibialis anterior) and patellar tendon allograft. IV.

Minimal effect of patella eversion on ligament balancing in cruciate-retaining total knee arthroplasty.

PubMed

Aunan, Eirik; Kibsgård, Thomas; Röhrl, Stephan M

2017-03-01

The effect of patellar eversion on ligament laxity measurements is still unclear. The purpose of this study was to investigate the influence of patellar eversion on medial and lateral ligament laxity measurements performed intra-operatively in total knee arthroplasty (TKA). A total of 49 knees (27 female) with mean age 70 years (42-83) and mean body mass index of 28.5 were operated consecutively with a cruciate-retaining prosthesis. Medial and lateral ligament laxity in extension and in 90° of flexion was measured with the spatula-method intra-operatively after implantation of the prosthetic components with the patella everted and thereafter with the patella repositioned. The corresponding changes in gap height and inclination were calculated. A statistically significant increase of 0.6 mm (p < 0.001) in ligament laxity (condylar lift-off) laterally in flexion was found with the patella repositioned compared to everted. No differences were found in extension or medially in flexion. Correspondingly, the flexion gap increased by 0.4 mm (p < 0.001) and the flexion gap inclination increased by 0.6° (p = 0.002) when the patella was repositioned. Earlier research has shown that ligament laxity must be at least 1-2 mm to cause inferior function after TKA. In the current study, we found that the effect of patellar eversion on ligament laxity measurements is too small to be considered clinically relevant. PROSPECTIVE STUDY EVALUATING THE EFFECT OF PATIENT CHARACTERISTICS: Level II.

Position of the patella in adults in central India: evaluation of the Insall-Salvati ratio.

PubMed

Upadhyay, Sachin; Raza, H K T; Srivastava, Pranay

2013-04-01

To assess the Insall-Salvati ratio in normal Indian adults to determine its applicability and the incidence of patella alta and baja in Indian populations. 800 knees in 200 men and 200 women aged 18 to 50 (mean, 30) years were evaluated using lateral radiographs. The knee was set in semi-flexion (30º) to enable good visualisation of the patellar tendon and its insertion into the tibia on radiographs. The length of the patellar tendon (LT) over the length of the patella (LP)-the Insall-Salvati ratio-was measured, using a vernier caliper. The mean LT/LP ratio was 1.14 (standard deviation, 0.18). Based on the 95% confidence interval, the ratio was considered normal if within ±40%. The LT/LP ratio was significantly higher in females than males (1.17 vs. 1.12, p<0.01). The cut-off point of patella alta was significantly greater in our Indian subjects than in western subjects (>1.5 vs. >1.2, p<0.0001). In the present cohort, the frequencies of patella alta (ratio, >1.5) and patella baja (ratio, <0.7) were 2.8% and 1%, respectively. The use of the Insall-Salvati ratio to determine the patellar position is less applicable to Indian populations in which squatting, sitting cross-legged, and kneeling are customs. We propose that the normal range of the ratio for squatters among Indian populations be 0.7 to 1.5.

The influence of kinematic conditions and design on the wear of patella-femoral replacements

PubMed Central

Maiti, Raman; Fisher, John; Rowley, Liam

2014-01-01

The success rate of patella-femoral arthroplasty varies between 44% and 90% in 17 years of follow-up. Several studies have been performed previously for assessing the surface wear in the patella-femoral joint. However, they have not included all six degrees of freedom. The aim of this study was to develop a six-axis patella-femoral joint simulator to assess the wear rate for two patellae designs (round and oval dome) at different kinematic conditions. An increase in patellar rotation from 1° to 4° led to a significantly (p<0.049) increased wear rate of round dome from 8.6 mm3/million cycles to 12.3 mm3/million cycles. The wear rate for oval dome increased from 6.3 mm3/million cycles to 14.5 mm3/million cycles. However, the increase was nonsignificant (p>0.08). The increase in wear rate was likely due to the higher cross shear. A decrease in patellar medial lateral displacement from passive to constrained resulted in a nonsignificant reduction in wear (p>0.06). There was no significant difference in wear rate between the two patellae designs (p>0.28). The volumetric wear under all conditions was positively correlated with the level of passive patellar tilt (rho>0.8). This is the first report of preclinical wear simulation of patella-femoral joint in a six-axis simulator under different kinematic conditions. PMID:24477888

Effect of eccentric exercise on the healing process of injured patellar tendon in rats.

PubMed

Nakamura, Kenichi; Kitaoka, Katsuhiko; Tomita, Katsuro

2008-07-01

Earlier studies have reported positive results from eccentric training in patients with tendon disorders. The reasons for the beneficial clinical effects of eccentric training are not known. Vascularization followed by regression of the vasculature enhances the healing response of injured tendons. Eccentric exercise induces a more beneficial healing response than concentric exercise. Sixty rats with patellar tendon injuries were divided into three groups: nonexercise controls (group N; n = 20); concentric exercise group (group C; n = 20); eccentric exercise group (group E; n = 20). Each rat was taught to run uphill or downhill for 14 days. Patellar tendons were removed 1, 4, 7, 10, and 14 days following injury. Vascular endothelial growth factor (VEGF), angiopoietin-1, and angiopoietin-2 were measured by reverse transcription polymerase chain reaction. In group C, VEGF mRNA was increased 1 and 4 days following injury but was decreased on days 7, 10, and 14. In group E, VEGF mRNA was elevated only on day 1. In group N, VEGF mRNA remained at a low level throughout all 14 days. The angiopoietin-2/angiopoietin-1 ratio was higher for group C than for group E. In the presence of VEGF, angiopoietin-1 promotes vessel stability, whereas angiopoietin-2 has the opposite effect. Eccentric exercise contributes to stabilized angiogenesis during the early phase of tendon injury. Conversely, concentric exercise, which induces destabilized angiogenesis, leads to a delayed healing response. Initiation of eccentric exercise immediately after tendon injury may help improve healing by reducing vascularity.

Variability of Measurement of Patellofemoral Indices with Knee Flexion and Quadriceps Contraction: An MRI-Based Anatomical Study

PubMed Central

Laugharne, Edward; Bali, Navi; Purushothamdas, Sanjay; Almallah, Faris; Kundra, Rik

2016-01-01

Purpose The purpose of this study was to investigate the impact of varying knee flexion and quadriceps activity on patellofemoral indices measured on magnetic resonance imaging (MRI). Materials and Methods MRI of the knee was performed in 20 patients for indications other than patellar or patellofemoral pathology. Axial and sagittal sequences were performed in full extension of the knee with the quadriceps relaxed, full extension of the knee with the quadriceps contracted, 30° flexion of the knee with the quadriceps relaxed, and 30° flexion with the quadriceps contracted. Bisect offset, patella tilt angle, Insall-Salvati ratio and Caton-Deschamps index were measured. Results With the knee flexed to 30° and quadriceps relaxed, the mean values of patellar tilt angle, bisect offset, Insall-Salvati ratio and Caton-Deschamps index were all within normal limits. With the knee extended and quadriceps contracted, the mean patellar tilt angle (normal value, <15°) was 14.6° and the bisect offset (normal value, <65%) was 65%, while the Caton-Deschamps index was 1.34 (normal range, 0.6 to 1.3). With the knee extended and quadriceps relaxed, the mean Caton-Deschamps index was 1.31. Conclusions MRI scanning of the knee in extension with the quadriceps contracted leads to elevated patellofemoral indices. MRI taken with the knee in 30° of flexion allows more reliable assessment of the patellofemoral joint and minimises the confounding effect of quadriceps contraction. PMID:27894177

Phase contrast imaging X-ray computed tomography: quantitative characterization of human patellar cartilage matrix with topological and geometrical features

NASA Astrophysics Data System (ADS)

Nagarajan, Mahesh B.; Coan, Paola; Huber, Markus B.; Diemoz, Paul C.; Wismüller, Axel

2014-03-01

Current assessment of cartilage is primarily based on identification of indirect markers such as joint space narrowing and increased subchondral bone density on x-ray images. In this context, phase contrast CT imaging (PCI-CT) has recently emerged as a novel imaging technique that allows a direct examination of chondrocyte patterns and their correlation to osteoarthritis through visualization of cartilage soft tissue. This study investigates the use of topological and geometrical approaches for characterizing chondrocyte patterns in the radial zone of the knee cartilage matrix in the presence and absence of osteoarthritic damage. For this purpose, topological features derived from Minkowski Functionals and geometric features derived from the Scaling Index Method (SIM) were extracted from 842 regions of interest (ROI) annotated on PCI-CT images of healthy and osteoarthritic specimens of human patellar cartilage. The extracted features were then used in a machine learning task involving support vector regression to classify ROIs as healthy or osteoarthritic. Classification performance was evaluated using the area under the receiver operating characteristic (ROC) curve (AUC). The best classification performance was observed with high-dimensional geometrical feature vectors derived from SIM (0.95 ± 0.06) which outperformed all Minkowski Functionals (p < 0.001). These results suggest that such quantitative analysis of chondrocyte patterns in human patellar cartilage matrix involving SIM-derived geometrical features can distinguish between healthy and osteoarthritic tissue with high accuracy.

Is the chronic painful tendinosis tendon a strong tendon?: a case study involving an Olympic weightlifter with chronic painful Jumper's knee.

PubMed

Gisslén, Karl; Ohberg, Lars; Alfredson, Håkan

2006-09-01

The chronic painful tendinosis tendon is generally considered a degenerated and weak tendon. However, this has not been scientifically verified, and is to be considered a hypothesis. We present here a case study involving a high-level Olympic weightlifter with chronic painful patellar tendinosis who started heavy-weight training very early after successful treatment with sclerosing injections. A 25-year-old super heavy-weight (+105 kg) Olympic weightlifter with 9 months duration of severe pain (prohibiting full training) in the proximal patellar tendon, where ultrasound and Doppler showed a widened tendon with structural changes and neovascularisation, was given one treatment with ultrasound and Doppler-guided injections of the sclerosing agent polidocanol. The injections targeted the neovessels posterior to the tendon. The patient was pain-free after the treatment, and already after 2-weeks he started with heavy-weight training (240 kg in deep squats) to try to qualify for the Olympics. Additional very heavy training on training camps, most often without having any discomfort or pain in the patellar tendon, resulted in Swedish records and ninth place at the European Championships 17 weeks after the treatment. Despite beating the national records, he did not qualify for the Olympics. Ultrasound and Doppler follow-ups have shown only a few remaining neovessels, and little structural tendon changes. This case questions previous theories about the weak tendinosis tendon, and stresses the importance of studies evaluating tendon strength.

Patellar tendon rupture repair using Dall-Miles cable.

PubMed

Shelbourne, K D; Darmelio, M P; Klootwyk, T E

2001-01-01

Ten patients underwent patellar tendon repair with end-to-end suture technique and medial and lateral retinacular repair, as well as reinforcement with a Dall-Miles cable through the patella and tibial tubercle. The cable was tensioned at 60 degrees of flexion to allow immediate range of motion to at least 100 degrees of flexion and to protect the repair from undue tension while healing. Accurate tendon length was obtained from a lateral radiograph of the noninvolved knee in 60 degrees of flexion. Patients were allowed to bear full weight as tolerated postoperatively. A knee immobilizer was worn for approximately 2 weeks when adequate muscular control of the leg was attained. The cable was removed 6-8 weeks postoperatively, at which time range of motion equal to the opposite extremity was sought. Full extension was obtained by 1 week postoperatively. Average postoperative knee flexion was 88 degrees at 2 weeks, 112 degrees at 1 month, 133 at 3 months, and 138 degrees at 6 months compared to flexion of 141 degrees in the noninvolved knee. Mean quadriceps muscle strength 1 year postoperatively was 72%+/-11% of the noninvolved leg. No patient had patella infera or rerupture after surgery. Repair of a patellar tendon rupture with end-to-end techniques reinforced with a Dall-Miles cable allows immediate rehabilitation without the need for prolonged immobilization. This technique allows restoration of full range of motion early postoperatively and enables patients to regain adequate quadriceps strength.

Short-term effects of arthrotomy with and without infrapatellar fat pad resection on the normal canine stifle.

PubMed

Fujita, Yukihiro; Nakajo, Tetsuya; Muto, Makoto

2017-07-01

To investigate the short-term effects of infrapatellar fat pad (IFP) resection in normal dogs. Experimental in vivo study. Five normal adult female beagle dogs. The IFP was resected via arthrotomy in the left stifle joint (experimental side) while the right stifle underwent arthrotomy alone (sham side). An orthopedic examination was performed every week for 4 weeks and synovial fluid was analyzed before and 4 weeks after the procedure. The ratio of the length of the patellar ligament to the patellar length (L:P) was calculated on a lateral radiograph of the stifle before, 2 and 4 weeks after the procedure. Patellar depth (PD) and the contact area (CA) between the femur and patella were calculated from computed tomographic images taken at 3 different stifle angles (extended, flexed, hyperflexed) before, immediately after, and 4 weeks following the procedure. The dogs were euthanatized 4 weeks after the procedure for macroscopic and microscopic evaluation of the patellofemoral joint. No difference was found between treatment groups throughout the study. No evidence of postoperative osteoarthritis was detected in any of the dogs. Orthopedic examinations, radiographs, and synovial fluid analyses remained within normal limits. Most PD, but not CA measurements, increased with time in both joints and at all stifle angles. Excision of the IFP subsequent to medial arthrotomy did not result in any measurable changes in the canine patellofemoral joint when compared with medial arthrotomy alone after 4 weeks of follow-up. © 2017 The American College of Veterinary Surgeons.

Computer-aided diagnosis for phase-contrast X-ray computed tomography: quantitative characterization of human patellar cartilage with high-dimensional geometric features.

PubMed

Nagarajan, Mahesh B; Coan, Paola; Huber, Markus B; Diemoz, Paul C; Glaser, Christian; Wismüller, Axel

2014-02-01

Phase-contrast computed tomography (PCI-CT) has shown tremendous potential as an imaging modality for visualizing human cartilage with high spatial resolution. Previous studies have demonstrated the ability of PCI-CT to visualize (1) structural details of the human patellar cartilage matrix and (2) changes to chondrocyte organization induced by osteoarthritis. This study investigates the use of high-dimensional geometric features in characterizing such chondrocyte patterns in the presence or absence of osteoarthritic damage. Geometrical features derived from the scaling index method (SIM) and statistical features derived from gray-level co-occurrence matrices were extracted from 842 regions of interest (ROI) annotated on PCI-CT images of ex vivo human patellar cartilage specimens. These features were subsequently used in a machine learning task with support vector regression to classify ROIs as healthy or osteoarthritic; classification performance was evaluated using the area under the receiver-operating characteristic curve (AUC). SIM-derived geometrical features exhibited the best classification performance (AUC, 0.95 ± 0.06) and were most robust to changes in ROI size. These results suggest that such geometrical features can provide a detailed characterization of the chondrocyte organization in the cartilage matrix in an automated and non-subjective manner, while also enabling classification of cartilage as healthy or osteoarthritic with high accuracy. Such features could potentially serve as imaging markers for evaluating osteoarthritis progression and its response to different therapeutic intervention strategies.

Open reduction and internal fixation of patellar fractures with tension band wiring through cannulated screws.

PubMed

Malik, Mudasir; Halwai, Manzoor Ahmad

2014-10-01

The purpose of this study was to evaluate effectiveness and safety of a relatively new technique of open reduction and internal fixation of displaced transverse patellar fractures with tension band wiring (TBW) through parallel cannulated compression screws. A total of 30 patients with displaced transverse patellar fracture were enrolled in this prospective study. Of the 30 patients, 20 patients had trauma due to fall, 5 due to road traffic accident, 2 due to fall of heavy object on the knee, 2 due to forced flexion of knee, and 1 had fracture due to being beaten. All 30 patients were treated with vertical skin exposure, fracture open reduction, and internal fixation by anterior TBW through 4.0 mm cannulated screws. The postoperative rehabilitation protocol was standardized. The patients were followed postsurgery to evaluate time required for radiographic bone union, knee joint range of motion (ROM), loss of fracture reduction, material failure, and the overall functional result of knee using Bostman scoring. All the fractures healed radiologically, at an average time of 10.7 weeks (range, 8-12 weeks). The average ROM arc was 129.7 degrees (range, 115-140 degrees). No patient had loss of fracture reduction, implant migration, or material failure. The average Bostman score was 28.6 out of 30. Anterior TBW through cannulated screws for displaced transverse fractures is safe and effective alternative treatment. Good functional results and recovery can be expected. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Removal of restrictions following primary THA with posterolateral approach does not increase the risk of early dislocation.

PubMed

Gromov, Kirill; Troelsen, Anders; Otte, Kristian Stahl; Ørsnes, Thue; Ladelund, Steen; Husted, Henrik

2015-01-01

Patient education and mobilization restrictions are often used in an attempt to reduce the risk of dislocation following primary THA. To date, there have been no studies investigating the safety of removal of mobilization restrictions following THA performed using a posterolateral approach. In this retrospective non-inferiority study, we investigated the rate of early dislocation following primary THA in an unselected patient cohort before and after removal of postoperative mobilization restrictions. From the Danish National Health Registry, we identified patients with early dislocation in 2 consecutive and unselected cohorts of patients who received primary THA at our institution from 2004 through 2008 (n = 946) and from 2010 through 2014 (n = 1,329). Patients in the first cohort were mobilized with functional restrictions following primary THA whereas patients in the second cohort were allowed unrestricted mobilization. Risk of early dislocation (within 90 days) was compared in the 2 groups and odds ratio (OR)-adjusted for possible confounders-was calculated. Reasons for early dislocation in the 2 groups were identified. When we adjusted for potential confounders, we found no increased risk of early dislocation within 90 days in patients who were mobilized without restrictions. Risk of dislocation within 90 days was lower (3.4% vs 2.8%), risk of dislocation within 30 days was lower (2.1% vs 2.0%), and risk of multiple dislocations (1.8% vs 1.1%) was lower in patients who were mobilized without restrictions, but not statistically significantly so. Increasing age was an independent risk factor for dislocation. Removal of mobilization restrictions from the mobilization protocol following primary THA performed with a posterolateral approach did not lead to an increased risk of dislocation within 90 days.

Theory of electron–phonon–dislon interacting system—toward a quantized theory of dislocations

DOE PAGES

Li, Mingda; Tsurimaki, Yoichiro; Meng, Qingping; ...

2018-02-05

In this paper, we provide a comprehensive theoretical framework to study how crystal dislocations influence the functional properties of materials, based on the idea of a quantized dislocation, namely a 'dislon'. In contrast to previous work on dislons which focused on exotic phenomenology, here we focus on their theoretical structure and computational power. We first provide a pedagogical introduction that explains the necessity and benefits of taking the dislon approach and why the dislon Hamiltonian takes its current form. Then, we study the electron–dislocation and phonon–dislocation scattering problems using the dislon formalism. Both the effective electron and phonon theories aremore » derived, from which the role of dislocations on electronic and phononic transport properties is computed. Compared with traditional dislocation scattering studies, which are intrinsically single-particle, low-order perturbation and classical quenched defect in nature, the dislon theory not only allows easy incorporation of quantum many-body effects such as electron correlation, electron–phonon interaction, and higher-order scattering events, but also allows proper consideration of the dislocation's long-range strain field and dynamic aspects on equal footing for arbitrary types of straight-line dislocations. This means that instead of developing individual models for specific dislocation scattering problems, the dislon theory allows for the calculation of electronic structure and electrical transport, thermal transport, optical and superconducting properties, etc, under one unified theory. Furthermore, the dislon theory has another advantage over empirical models in that it requires no fitting parameters. The dislon theory could serve as a major computational tool to understand the role of dislocations on multiple materials' functional properties at an unprecedented level of clarity, and may have wide applications in dislocated energy materials.« less

Theory of electron–phonon–dislon interacting system—toward a quantized theory of dislocations

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

Li, Mingda; Tsurimaki, Yoichiro; Meng, Qingping

In this paper, we provide a comprehensive theoretical framework to study how crystal dislocations influence the functional properties of materials, based on the idea of a quantized dislocation, namely a 'dislon'. In contrast to previous work on dislons which focused on exotic phenomenology, here we focus on their theoretical structure and computational power. We first provide a pedagogical introduction that explains the necessity and benefits of taking the dislon approach and why the dislon Hamiltonian takes its current form. Then, we study the electron–dislocation and phonon–dislocation scattering problems using the dislon formalism. Both the effective electron and phonon theories aremore » derived, from which the role of dislocations on electronic and phononic transport properties is computed. Compared with traditional dislocation scattering studies, which are intrinsically single-particle, low-order perturbation and classical quenched defect in nature, the dislon theory not only allows easy incorporation of quantum many-body effects such as electron correlation, electron–phonon interaction, and higher-order scattering events, but also allows proper consideration of the dislocation's long-range strain field and dynamic aspects on equal footing for arbitrary types of straight-line dislocations. This means that instead of developing individual models for specific dislocation scattering problems, the dislon theory allows for the calculation of electronic structure and electrical transport, thermal transport, optical and superconducting properties, etc, under one unified theory. Furthermore, the dislon theory has another advantage over empirical models in that it requires no fitting parameters. The dislon theory could serve as a major computational tool to understand the role of dislocations on multiple materials' functional properties at an unprecedented level of clarity, and may have wide applications in dislocated energy materials.« less

Computational issues in the simulation of two-dimensional discrete dislocation mechanics

NASA Astrophysics Data System (ADS)

Segurado, J.; LLorca, J.; Romero, I.

2007-06-01

The effect of the integration time step and the introduction of a cut-off velocity for the dislocation motion was analysed in discrete dislocation dynamics (DD) simulations of a single crystal microbeam. Two loading modes, bending and uniaxial tension, were examined. It was found that a longer integration time step led to a progressive increment of the oscillations in the numerical solution, which would eventually diverge. This problem could be corrected in the simulations carried out in bending by introducing a cut-off velocity for the dislocation motion. This strategy (long integration times and a cut-off velocity for the dislocation motion) did not recover, however, the solution computed with very short time steps in uniaxial tension: the dislocation density was overestimated and the dislocation patterns modified. The different response to the same numerical algorithm was explained in terms of the nature of the dislocations generated in each case: geometrically necessary in bending and statistically stored in tension. The evolution of the dislocation density in the former was controlled by the plastic curvature of the beam and was independent of the details of the simulations. On the contrary, the steady-state dislocation density in tension was determined by the balance between nucleation of dislocations and those which are annihilated or which exit the beam. Changes in the DD imposed by the cut-off velocity altered this equilibrium and the solution. These results point to the need for detailed analyses of the accuracy and stability of the dislocation dynamic simulations to ensure that the results obtained are not fundamentally affected by the numerical strategies used to solve this complex problem.

Risk of Revision Was Not Reduced by a Double-bundle ACL Reconstruction Technique: Results From the Scandinavian Registers.

PubMed

Aga, Cathrine; Kartus, Jüri-Tomas; Lind, Martin; Lygre, Stein Håkon Låstad; Granan, Lars-Petter; Engebretsen, Lars

2017-10-01

Double-bundle anterior cruciate ligament (ACL) reconstruction has demonstrated improved biomechanical properties and moderately better objective outcomes compared with single-bundle reconstructions. This could make an impact on the rerupture rate and reduce the risk of revisions in patients undergoing double-bundle ACL reconstruction compared with patients reconstructed with a traditional single-bundle technique. The National Knee Ligament Registers in Scandinavia provide information that can be used to evaluate the revision outcome after ACL reconstructions. The purposes of the study were (1) to compare the risk of revision between double-bundle and single-bundle reconstructions, reconstructed with autologous hamstring tendon grafts; (2) to compare the risk of revision between double-bundle hamstring tendon and single-bundle bone-patellar tendon-bone autografts; and (3) to compare the hazard ratios for the same two research questions after Cox regression analysis was performed. Data collection of primary ACL reconstructions from the National Knee Ligament Registers in Denmark, Norway, and Sweden from July 1, 2005, to December 31, 2014, was retrospectively analyzed. A total of 60,775 patients were included in the study; 994 patients were reconstructed with double-bundle hamstring tendon grafts, 51,991 with single-bundle hamstring tendon grafts, and 7790 with single-bundle bone-patellar tendon-bone grafts. The double-bundle ACL-reconstructed patients were compared with the two other groups. The risk of revision for each research question was detected by the risk ratio, hazard ratio, and the corresponding 95% confidence intervals. Kaplan-Meier analysis was used to estimate survival at 1, 2, and 5 years for the three different groups. Furthermore, a Cox proportional hazard regression model was applied and the hazard ratios were adjusted for country, age, sex, meniscal or chondral injury, and utilized fixation devices on the femoral and tibial sides. There were no differences in the crude risk of revision between the patients undergoing the double-bundle technique and the two other groups. A total of 3.7% patients were revised in the double-bundle group (37 of 994 patients) versus 3.8% in the single-bundle hamstring tendon group (1952 of 51,991; risk ratio, 1.01; 95% confidence interval (CI), 0.73-1.39; p = 0.96), and 2.8% of the patients were revised in the bone-patellar tendon-bone group (219 of the 7790 bone-patellar tendon-bone patients; risk ratio, 0.76; 95% CI, 0.54-1.06; p = 0.11). Cox regression analysis with adjustment for country, age, sex, menisci or cartilage injury, and utilized fixation device on the femoral and tibial sides, did not reveal any further difference in the risk of revision between the single-bundle hamstring tendon and double-bundle hamstring tendon groups (hazard ratio, 1.18; 95% CI, 0.85-1.62; p = 0.33), but the adjusted hazard ratio showed a lower risk of revision in the single-bundle bone-patellar tendon-bone group compared with the double-bundle group (hazard ratio, 0.62; 95% CI, 0.43-0.90; p = 0.01). Comparisons of the graft revision rates reported separately for each country revealed that double-bundle hamstring tendon reconstructions in Sweden had a lower hazard ratio compared with the single-bundle hamstring tendon reconstructions (hazard ratio, 1.00 versus 1.89; 95% CI, 1.09-3.29; p = 0.02). Survival at 5 years after index surgery was 96.0% for the double-bundle group, 95.4% for the single-bundle hamstring tendon group, and 97.0% for the single-bundle bone-patellar tendon-bone group. Based on the data from all three national registers, the risk of revision was not influenced by the reconstruction technique in terms of using single- or double-bundle hamstring tendons, although national differences in survival existed. Using bone-patellar tendon-bone grafts lowered the risk of revision compared with double-bundle hamstring tendon grafts. These findings should be considered when deciding what reconstruction technique to use in ACL-deficient knees. Future studies identifying the reasons for graft rerupture in single- and double-bundle reconstructions would be of interest to understand the findings of the present study. Level III, therapeutic study.

Non-Traumatic Anterior Dislocation of a Total Knee Replacement Associated with Neurovascular Injury

PubMed Central

Aderinto, Joseph; Gross, Allan E; Rittenhouse, Bryan

2009-01-01

Prosthetic total knee replacements rarely dislocate. When dislocation does occur, it is usually in a posterior direction in association with a posterior stabilised, cruciate-sacrificing prosthesis. Neurovascular injury is unusual. In this report, we describe a case of anterior dislocation of a cruciate-retaining total knee replacement in a 67-year-old woman. The dislocation occurred in the absence of overt trauma and resulted in severe neurovascular injury. PMID:19686618

Posterior dislocation following revision total knee replacement arthroplasty: a case report and literature analysis.

PubMed

Lee, Ho Min; Kim, Jong Pil; Chung, Phil Hyun; Kang, Suk; Kim, Young Sung; Go, Bo Seong

2018-05-24

Knee dislocation following total knee replacement arthroplasty is a rare but serious complication. The incidence of dislocation following primary total knee arthroplasty with posterior stabilized implants ranges from 0.15 to 0.5%, and posterior dislocation after revision total knee arthroplasty is even rarer. Here, we report the case of a 76-year-old male who presented with posterior dislocation after posterior stabilized revision total knee arthroplasty.

Pyramidal dislocation induced strain relaxation in hexagonal structured InGaN/AlGaN/GaN multilayer

NASA Astrophysics Data System (ADS)

Yan, P. F.; Du, K.; Sui, M. L.

2012-10-01

Due to the special dislocation slip systems in hexagonal lattice, dislocation dominated deformations in hexagonal structured multilayers are significantly different from that in cubic structured systems. In this work, we have studied the strain relaxation mechanism in hexagonal structured InGaN/AlGaN/GaN multilayers with transmission electron microscopy. Due to lattice mismatch, the strain relaxation was found initiated with the formation of pyramidal dislocations. Such dislocations locally lie at only one preferential slip direction in the hexagonal lattice. This preferential slip causes a shear stress along the basal planes and consequently leads to dissociation of pyramidal dislocations and operation of the basal plane slip system. The compressive InGaN layers and "weak" AlGaN/InGaN interfaces stimulate the dissociation of pyramidal dislocations at the interfaces. These results enhance the understanding of interactions between dislocations and layer interfaces and shed new lights on deformation mechanism in hexagonal-lattice multilayers.

Atomic-scale dynamics of edge dislocations in Ni and concentrated solid solution NiFe alloys

DOE PAGES

Zhao, Shijun; Osetsky, Yuri N.; Zhang, Yanwen; ...

2017-01-19

Single-phase concentrated solid solution alloys (CSAs), including high entropy alloys, exhibit excellent mechanical properties compared to conventional dilute alloys. However, the origin of this observation is not clear yet because the dislocation properties in CSAs are poorly understood. In this work, the mobility of a <110>{111} edge dislocation in pure Ni and equiatomic solid solution Ni 0.5Fe 0.5 (NiFe) is studied using molecular dynamics simulations with different empirical potentials. The threshold stress to initiate dislocation movement in NiFe is found to be much higher compared to pure Ni. The drag coefficient of the dislocation motion calculated from the linear regimemore » of dislocation velocities versus applied stress suggests that the movement of dislocations in NiFe is strongly damped compared to that in Ni. The present results indicate that the mobility of edge dislocations in fcc CSAs are controlled by the fluctuations in local stacking fault energy caused by the local variation of alloy composition.« less

Computational modelling of mesoscale dislocation patterning and plastic deformation of single crystals

NASA Astrophysics Data System (ADS)

Xia, Shengxu; El-Azab, Anter

2015-07-01

We present a continuum dislocation dynamics model that predicts the formation of dislocation cell structure in single crystals at low strains. The model features a set of kinetic equations of the curl type that govern the space and time evolution of the dislocation density in the crystal. These kinetic equations are coupled to stress equilibrium and deformation kinematics using the eigenstrain approach. A custom finite element method has been developed to solve the coupled system of equations of dislocation kinetics and crystal mechanics. The results show that, in general, dislocations self-organize in patterns under their mutual interactions. However, the famous dislocation cell structure has been found to form only when cross slip is implemented in the model. Cross slip is also found to lower the yield point, increase the hardening rate, and sustain an increase in the dislocation density over the hardening regime. Analysis of the cell structure evolution reveals that the average cell size decreases with the applied stress, which is consistent with the similitude principle.

Pipe and grain boundary diffusion of He in UO 2

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

Galvin, C. O.T.; Cooper, M. W. D.; Fossati, P. C. M.

Molecular dynamics simulations have been conducted to study the effects of dislocations and grain boundaries on He diffusion inmore » $$\\text{U}{{\\text{O}}_{2}}$$ . Calculations were carried out for the {100}, {110} and {111} $$\\langle 1\\,1\\,0\\rangle $$ edge dislocations, the screw $$\\langle 1\\,1\\,0\\rangle $$ dislocation and Σ5, Σ13, Σ19 and Σ25 tilt grain boundaries. He diffusivity as a function of distance from the dislocation core and grain boundaries was investigated for the temperature range 2300–3000 K. An enhancement in diffusivity was predicted within 20 Å of the dislocations or grain boundaries. Further investigation showed that He diffusion in the edge dislocations follows anisotropic behaviour along the dislocation core, suggesting that pipe diffusion occurs. Here, an Arrhenius plot of He diffusivity against the inverse of temperature was also presented and the activation energy calculated for each structure, as a function of distance from the dislocation or grain boundary.« less

Ultrasonic Study of Dislocation Dynamics in Lithium -

NASA Astrophysics Data System (ADS)

Han, Myeong-Deok

1987-09-01

Experimental studies of dislocation dynamics in LiF single crystals, using ultrasonic techniques combined with dynamic loading, were performed to investigate the time evolution of the plastic deformation process under a short stress pulse at room temperature, and the temperature dependence of the dislocation damping mechanism in the temperature range 25 - 300(DEGREES)K. From the former, the time dependence of the ultrasonic attenuation was understood as resulting from dislocation multiplication followed by the evolution of mobile dislocations to immobile ones under large stress. From the latter, the temperature dependence of the ultrasonic attenuation was interpreted as due to the motion of the dislocation loops overcoming the periodic Peierls potential barrier in a manner analogous to the motion of a thermalized sine-Gordon chain under a small stress. The Peierls stress obtained from the experimental results by application of Seeger's relaxation model with exponential dislocation length distribution was 4.26MPa, which is consistent with the lowest stress for the linear relation between the dislocation velocity and stress observed by Flinn and Tinder.

Chronic bilateral dislocation of temporomandibular joint.

PubMed

Shakya, S; Ongole, R; Sumanth, K N; Denny, C E

2010-01-01

Dislocation of the condyle of the mandible is a common condition that may occur in an acute or chronic form. It is characterised by inability to close the mouth with or without pain. Dislocation has to be differentiated from subluxation which is a self reducible condition. Dislocation can occur in any direction with anterior dislocation being the commonest one. Various predisposing factors have been associated with dislocation like muscle fatigue and spasm, the defect in the bony surface like shallow articular eminence, and laxity of the capsular ligament. People with defect in collagen synthesis like Ehler Danlos syndrome, Marfan syndrome are said to be genetically predisposed to this condition. Various treatment modalities have been used ranging from conservative techniques to surgical methods. Acute dislocations can be reduced manually or with conservative approach and recurrent and chronic cases can be reduced by surgical intervention. Though the dislocation in our case was 4 months a simple manual reduction proved to be successful. We believe that manual reduction can be attempted as first line of treatment prior to surgical intervention.

Period-doubling reconstructions of semiconductor partial dislocations

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

Park, Ji -Sang; Huang, Bing; Wei, Su -Huai

2015-09-18

Atomic-scale understanding and control of dislocation cores is of great technological importance, because they act as recombination centers for charge carriers in optoelectronic devices. Using hybrid density-functional calculations, we present period-doubling reconstructions of a 90 degrees partial dislocation in GaAs, for which the periodicity of like-atom dimers along the dislocation line varies from one to two, to four dimers. The electronic properties of a dislocation change drastically with each period doubling. The dimers in the single-period dislocation are able to interact, to form a dispersive one-dimensional band with deep-gap states. However, the inter-dimer interaction for the double-period dislocation becomes significantlymore » reduced; hence, it is free of mid-gap states. The Ga core undergoes a further period-doubling transition to a quadruple-period reconstruction induced by the formation of small hole polarons. In conclusion, the competition between these dislocation phases suggests a new passivation strategy via population manipulation of the detrimental single-period phase.« less

Pipe and grain boundary diffusion of He in UO 2

DOE PAGES

Galvin, C. O.T.; Cooper, M. W. D.; Fossati, P. C. M.; ...

2016-10-12

Molecular dynamics simulations have been conducted to study the effects of dislocations and grain boundaries on He diffusion inmore » $$\\text{U}{{\\text{O}}_{2}}$$ . Calculations were carried out for the {100}, {110} and {111} $$\\langle 1\\,1\\,0\\rangle $$ edge dislocations, the screw $$\\langle 1\\,1\\,0\\rangle $$ dislocation and Σ5, Σ13, Σ19 and Σ25 tilt grain boundaries. He diffusivity as a function of distance from the dislocation core and grain boundaries was investigated for the temperature range 2300–3000 K. An enhancement in diffusivity was predicted within 20 Å of the dislocations or grain boundaries. Further investigation showed that He diffusion in the edge dislocations follows anisotropic behaviour along the dislocation core, suggesting that pipe diffusion occurs. Here, an Arrhenius plot of He diffusivity against the inverse of temperature was also presented and the activation energy calculated for each structure, as a function of distance from the dislocation or grain boundary.« less

Uncovering the inertia of dislocation motion and negative mechanical response in crystals.

PubMed

Tang, Yizhe

2018-01-09

Dislocations are linear defects in crystals and their motion controls crystals' mechanical behavior. The dissipative nature of dislocation propagation is generally accepted although the specific mechanisms are still not fully understood. The inertia, which is undoubtedly the nature of motion for particles with mass, seems much less convincing for configuration propagation. We utilize atomistic simulations in conditions that minimize dissipative effects to enable uncovering of the hidden nature of dislocation motion, in three typical model metals Mg, Cu and Ta. We find that, with less/no dissipation, dislocation motion is under-damped and explicitly inertial at both low and high velocities. The inertia of dislocation motion is intrinsic, and more fundamental than the dissipative nature. The inertia originates from the kinetic energy imparted from strain energy and stored in the moving core. Peculiar negative mechanical response associated with the inertia is also discovered. These findings shed light on the fundamental nature of dislocation motion, reveal the underlying physics, and provide a new physical explanation for phenomena relevant to high-velocity dislocations.

Electron energy can oscillate near a crystal dislocation

DOE PAGES

Li, Mingda; Cui, Wenping; Dresselhaus, Mildred S.; ...

2017-01-25

Crystal dislocations govern the plastic mechanical properties of materials but also affect the electrical and optical properties. However, a fundamental and quantitative quantum field theory of a dislocation has remained undiscovered for decades. Here in this article we present an exactly-solvable one-dimensional quantum field theory of a dislocation, for both edge and screw dislocations in an isotropic medium, by introducing a new quasiparticle which we have called the ‘dislon’. The electron-dislocation relaxation time can then be studied directly from the electron self-energy calculation, which is reducible to classical results. In addition, we predict that the electron energy will experience anmore » oscillation pattern near a dislocation. Compared with the electron density’s Friedel oscillation, such an oscillation is intrinsically different since it exists even with only single electron is present. With our approach, the effect of dislocations on materials’ non-mechanical properties can be studied at a full quantum field theoretical level.« less

Superolateral dislocation of an intact mandibular condyle into the temporal fossa: case report and literature review.

PubMed

Sharma, Divashree; Khasgiwala, Ankit; Maheshwari, Bharat; Singh, Charanpreet; Shakya, Neelam

2017-02-01

Temporomandibular joint dislocation refers to the dislodgement of mandibular condyle from the glenoid fossa. Anterior and anteromedial dislocations of the mandibular condyle are frequently reported in the literature, but superolateral dislocation is a rare presentation. This report outlines a case of superolateral dislocation of an intact mandibular condyle that occurred in conjunction with an ipsilateral mandibular parasymphysis fracture. A review of the clinical features of superolateral dislocation of the mandibular condyle and the possible techniques of its reduction ranging from the most conservative means to extensive surgical interventions is presented. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Ipsilateral fracture dislocation of the shoulder and elbow: A case report and literature review

PubMed Central

Behr, Ian; Blint, Andy; Trenhaile, Scott

2013-01-01

Ipsilateral dislocation of the shoulder and elbow is an uncommon injury. A literature review identified nine previously described cases. We are reporting a unique case of ipsilateral posterior shoulder dislocation and anterior elbow dislocation along with concomitant intra-articular fractures of both joints. This is the first report describing this combination of injuries. Successful treatment generally occurs with closed reduction of ipsilateral shoulder and elbow dislocations, usually reducing the elbow first. When combined with a fracture at one or both locations, closed reduction of the dislocations in conjunction with appropriate fracture management can result in a positive functional outcome. PMID:26403884

Bilateral posterior fracture-dislocation of the shoulder: Report of two cases

PubMed Central

Claro, Rui; Sousa, Ricardo; Massada, Marta; Ramos, Joaquim; Lourenço, José M.

2009-01-01

Bilateral posterior fracture-dislocation of the shoulder is a very rare injury. Almost 50% of bilateral posterior dislocations are due to a convulsive seizure, rising to 90% if the dislocations are associated with fractures. Electric shock accounts for less than 5% of bilateral posterior dislocations of the shoulder. A systematization of the clinical and radiological approach, followed by an early diagnosis and proper surgical treatment is essential. Authors report 2 cases of bilateral posterior fracture-dislocation of the shoulder, one caused by a convulsive seizure and the other by an electric shock. A review of literature and a treatment protocol are also presented. PMID:20661400

Simultaneous dislocation of the metacarpophalangeal and interphalangeal joints of the thumb.

PubMed

Tabib, William; Sayegh, Samir

2002-01-01

Combined dislocation of the metacarpophalangeal and interphalangeal joints of the thumb is uncommon. We know of only four previously reported cases. We report a new case characterised by dorsal dislocation of both joints. Because of entrapment of the volar plate, open reduction at the interphalangeal joint was necessary. The metacarpophalangeal dislocation was treated by closed reduction. After three weeks of immobilisation, physiotherapy resulted in a satisfactory outcome. Even if the diagnosis of dislocation of the interphalangeal joint is obvious it would be easy to overlook a simultaneous dislocation of the metacarpophalangeal joint with serious consequences. Whole hand examination remains an essential rule.

Effects of doping impurity and growth orientation on dislocation generation in GaAs crystals grown from the melt: A qualitative finite-element study

NASA Astrophysics Data System (ADS)

Zhu, X. A.; Tsai, C. T.

2000-09-01

Dislocations in gallium arsenide (GaAs) crystals are generated by excessive thermal stresses induced during the crystal growth process. The presence of dislocations has adverse effects on the performance and reliability of the GaAs-based devices. It is well known that dislocation density can be significantly reduced by doping impurity atoms into a GaAs crystal during its growth process. A viscoplastic constitutive equation that couples the microscopic dislocation density with the macroscopic plastic deformation is employed in a crystallographic finite element model for calculating the dislocation density generated in the GaAs crystal during its growth process. The dislocation density is considered as an internal state variable and the drag stress caused by doping impurity is included in this constitutive equation. A GaAs crystal grown by the vertical Bridgman process is adopted as an example to study the influences of doping impurity and growth orientation on dislocation generation. The calculated results show that doping impurity can significantly reduce the dislocation density generated in the crystal. The level of reduction is also influenced by the growth orientation during the crystal growth process.

Dislocation mechanism based model for stage II fatigue crack propagation rate

NASA Technical Reports Server (NTRS)

Mazumdar, P. K.

1986-01-01

Repeated plastic deformation, which of course depends on dislocation mechanism, at or near the crack tip leads to the fatigue crack propagation. By involving the theory of thermally activated flow and the cumulative plastic strain criterion, an effort is made here to model the stage II fatigue crack propagation rate in terms of the dislocation mechanism. The model, therefore, provides capability to ascertain: (1) the dislocation mechanism (and hence the near crack tip microstructures) assisting the crack growth, (2) the relative resistance of dislocation mechanisms to the crack growth, and (3) the fracture surface characteristics and its interpretation in terms of the dislocation mechanism. The local microstructure predicted for the room temperature crack growth in copper by this model is in good agreement with the experimental results taken from the literature. With regard to the relative stability of such dislocation mechanisms as the cross-slip and the dislocation intersection, the model suggests an enhancement of crack growth rate with an ease of cross-slip which in general promotes dislocation cell formation and is common in material which has high stacking fault energy (produces wavy slips). Cross-slip apparently enhances crack growth rate by promoting slip irreversibility and fracture surface brittleness to a greater degree.

Work Hardening, Dislocation Structure, and Load Partitioning in Lath Martensite Determined by In Situ Neutron Diffraction Line Profile Analysis

NASA Astrophysics Data System (ADS)

Harjo, Stefanus; Kawasaki, Takuro; Tomota, Yo; Gong, Wu; Aizawa, Kazuya; Tichy, Geza; Shi, Zengmin; Ungár, Tamas

2017-09-01

A lath martensite steel containing 0.22 mass pct carbon was analyzed in situ during tensile deformation by high-resolution time-of-flight neutron diffraction to clarify the large work-hardening behavior at the beginning of plastic deformation. The diffraction peaks in plastically deformed states exhibit asymmetries as the reflection of redistributions of the stress and dislocation densities/arrangements in two lath packets: soft packet, where the dislocation glides are favorable, and hard packet, where they are unfavorable. The dislocation density was as high as 1015 m-2 in the as-heat-treated state. During tensile straining, the load and dislocation density became different between the two lath packets. The dislocation character and arrangement varied in the hard packet but hardly changed in the soft packet. In the hard packet, dislocations that were mainly screw-type in the as-heat-treated state became primarily edge-type and rearranged towards a dipole character related to constructing cell walls. The hard packet played an important role in the work hardening in martensite, which could be understood by considering the increase in dislocation density along with the change in dislocation arrangement.

Mechanical annealing under low-amplitude cyclic loading in micropillars

NASA Astrophysics Data System (ADS)

Cui, Yi-nan; Liu, Zhan-li; Wang, Zhang-jie; Zhuang, Zhuo

2016-04-01

Mechanical annealing has been demonstrated to be an effective method for decreasing the overall dislocation density in submicron single crystal. However, simultaneously significant shape change always unexpectedly happens under extremely high monotonic loading to drive the pre-existing dislocations out of the free surfaces. In the present work, through in situ TEM experiments it is found that cyclic loading with low stress amplitude can drive most dislocations out of the submicron sample with virtually little change of the shape. The underlying dislocation mechanism is revealed by carrying out discrete dislocation dynamic (DDD) simulations. The simulation results indicate that the dislocation density decreases within cycles, while the accumulated plastic strain is small. By comparing the evolution of dislocation junction under monotonic, cyclic and relaxation deformation, the cumulative irreversible slip is found to be the key factor of promoting junction destruction and dislocation annihilation at free surface under low-amplitude cyclic loading condition. By introducing this mechanics into dislocation density evolution equations, the critical conditions for mechanical annealing under cyclic and monotonic loadings are discussed. Low-amplitude cyclic loading which strengthens the single crystal without seriously disturbing the structure has the potential applications in the manufacture of defect-free nano-devices.

Asymmetric, compressive, SiGe epilayers on Si grown by lateral liquid-phase epitaxy utilizing a distinction between dislocation nucleation and glide critical thicknesses

NASA Astrophysics Data System (ADS)

O'Reilly, Andrew J.; Quitoriano, Nathaniel

2018-01-01

Uniaxially strained Si1-xGex channels have been proposed as a solution for high mobility channels in next-generation MOSFETS to ensure continued device improvement as the benefits from further miniaturisation are diminishing. Previously proposed techniques to deposit uniaxially strained Si1-xGex epilayers on Si (0 0 1) substrates require multiple deposition steps and only yielded thin strips of uniaxially strained films. A lateral liquid-phase epitaxy (LLPE) technique was developed to deposit a blanket epilayer of asymmetrically strained Si97.4Ge2.6 on Si in a single step, where the epilayer was fully strained in the growth direction and 31% strain-relaxed in the orthogonal direction. The LLPE technique promoted the glide of misfit dislocations, which nucleated in a region with an orthogonal misfit dislocation network, into a region where the dislocation nucleation was inhibited. This created an array of parallel misfit dislocations which were the source of the asymmetric strain. By observing the thicknesses at which the dislocation network transitions from orthogonal to parallel and at which point dislocation glide is exhausted, the separate critical thicknesses for dislocation nucleation and dislocation glide can be determined.

Recombination-related properties of a-screw dislocations in GaN: A combined CL, EBIC, TEM study

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

Medvedev, O. S., E-mail: o.s.medvedev@spbu.ru; Mikhailovskii, V. Yu.; IRC for Nanotechnology, Research Park, St.-Petersburg State University

2016-06-17

Cathodoluminescence (CL), electron beam current (EBIC) and transmission electron microscopy (TEM) techniques have been applied to investigate recombination properties and structure of freshly introduced dislocations in low-ohmic GaN crystals. It was confirmed that the only a-screw dislocations exhibited an intense characteristic dislocation-related luminescence (DRL) which persisted up to room temperature and was red-shifted by about 0.3 eV with respect to the band gap energy not only in HVPE but also in MOCVD grown samples. EBIC contrast of the dislocations was found to be temperature independent indicating that the dislocation-related recombination level is situated below 200 meV with respect of conductionmore » band minimum. With the increasing of the magnification of the dislocation TEM cross-sectional images they were found to disappear, probably, due to the recombination enhanced dislocation glide (REDG) under electron beam exposure which was immediately observed in CL investigations on a large scale. The stacking fault ribbon in the core of dissociated a-screw dislocation which form a quantum well for electrons was proposed to play an important role both in DRL spectrum formation and in REDG.« less

Model for threading dislocations in metamorphic tandem solar cells on GaAs (001) substrates

NASA Astrophysics Data System (ADS)

Song, Yifei; Kujofsa, Tedi; Ayers, John E.

2018-02-01

We present an approximate model for the threading dislocations in III-V heterostructures and have applied this model to study the defect behavior in metamorphic triple-junction solar cells. This model represents a new approach in which the coefficient for second-order threading dislocation annihilation and coalescence reactions is considered to be determined by the length of misfit dislocations, LMD, in the structure, and we therefore refer to it as the LMD model. On the basis of this model we have compared the average threading dislocation densities in the active layers of triple junction solar cells using linearly-graded buffers of varying thicknesses as well as S-graded (complementary error function) buffers with varying thicknesses and standard deviation parameters. We have shown that the threading dislocation densities in the active regions of metamorphic tandem solar cells depend not only on the thicknesses of the buffer layers but on their compositional grading profiles. The use of S-graded buffer layers instead of linear buffers resulted in lower threading dislocation densities. Moreover, the threading dislocation densities depended strongly on the standard deviation parameters used in the S-graded buffers, with smaller values providing lower threading dislocation densities.

The influence of anisotropy on the core structure of Shockley partial dislocations within FCC materials

NASA Astrophysics Data System (ADS)

Szajewski, B. A.; Hunter, A.; Luscher, D. J.; Beyerlein, I. J.

2018-01-01

Both theoretical and numerical models of dislocations often necessitate the assumption of elastic isotropy to retain analytical tractability in addition to reducing computational load. As dislocation based models evolve towards physically realistic material descriptions, the assumption of elastic isotropy becomes increasingly worthy of examination. We present an analytical dislocation model for calculating the full dissociated core structure of dislocations within anisotropic face centered cubic (FCC) crystals as a function of the degree of material elastic anisotropy, two misfit energy densities on the γ-surface ({γ }{{isf}}, {γ }{{usf}}) and the remaining elastic constants. Our solution is independent of any additional features of the γ-surface. Towards this pursuit, we first demonstrate that the dependence of the anisotropic elasticity tensor on the orientation of the dislocation line within the FCC crystalline lattice is small and may be reasonably neglected for typical materials. With this approximation, explicit analytic solutions for the anisotropic elasticity tensor {B} for both nominally edge and screw dislocations within an FCC crystalline lattice are devised, and employed towards defining a set of effective isotropic elastic constants which reproduce fully anisotropic results, however do not retain the bulk modulus. Conversely, Hill averaged elastic constants which both retain the bulk modulus and reasonably approximate the dislocation core structure are employed within subsequent numerical calculations. We examine a wide range of materials within this study, and the features of each partial dislocation core are sufficiently localized that application of discrete linear elasticity accurately describes the separation of each partial dislocation core. In addition, the local features (the partial dislocation core distribution) are well described by a Peierls-Nabarro dislocation model. We develop a model for the displacement profile which depends upon two disparate dislocation length scales which describe the core structure; (i) the equilibrium stacking fault width between two Shockley partial dislocations, R eq and (ii) the maximum slip gradient, χ, of each Shockley partial dislocation. We demonstrate excellent agreement between our own analytic predictions, numerical calculations, and R eq computed directly by both ab-initio and molecular statics methods found elsewhere within the literature. The results suggest that understanding of various plastic mechanisms, e.g., cross-slip and nucleation may be augmented with the inclusion of elastic anisotropy.

Morphological changes in the cervical intervertebral foramen dimensions with unilateral facet joint dislocation.

PubMed

Ebraheim, Nabil A; Liu, Jiayong; Ramineni, Satheesh K; Liu, Xiaochen; Xie, Joe; Hartman, Ryan G; Goel, Vijay K

2009-11-01

Many investigators have conducted studies to determine the biomechanics, causes, complications and treatment of unilateral facet joint dislocation in the cervical spine. However, there is no quantitative data available on morphological changes in the intervertebral foramen of the cervical spine following unilateral facet joint dislocation. These data are important to understand the cause of neurological compromise following unilateral facet joint dislocation. Eight embalmed human cadaver cervical spine specimens ranging from level C1-T1 were used. The nerve roots of these specimens at C5-C6 level were marked by wrapping a 0.12mm diameter wire around them. Unilateral facet dislocation at C5-C6 level was simulated by serially sectioning the corresponding ligamentous structures. A CT scan of the specimens was obtained before and after the dislocation was simulated. A sagittal plane through the centre of the pedicle and facet joint was constructed and used for measurement. The height and area of the intervertebral foramen, the facet joint space, nerve root diameter and area, and vertebral alignment both before and after dislocation were evaluated. The intervertebral foramen area changed from 50.72+/-0.88mm(2) to 67.82+/-4.77mm(2) on the non-dislocated side and from 41.39+/-1.11mm(2) to 113.77+/-5.65mm(2) on the dislocated side. The foraminal heights changed from 9.02+/-0.30mm to 10.52+/-0.50mm on the non-dislocated side and 10.43+/-0.50mm to 17.04+/-0.96mm on the dislocated side. The facet space area in the sagittal plane changed from 6.80+/-0.80mm(2) to 40.02+/-1.40mm(2) on the non-dislocated side. The C-5 anterior displacement showed a great change from 0mm to 5.40+/-0.24mm on the non-dislocated side and from 0mm to 3.42+/-0.20mm on the dislocated side. Neither of the nerve roots on either side showed a significant change in size. The lack of change in nerve root area indicates that the associated nerve injury with unilateral facet joint dislocation is probably due to distraction rather than due to direct nerve root compression.

FAST TRACK COMMUNICATION High rate straining of tantalum and copper

NASA Astrophysics Data System (ADS)

Armstrong, R. W.; Zerilli, F. J.

2010-12-01

High strain rate measurements reported recently for several tantalum and copper crystal/polycrystal materials are shown to follow dislocation mechanics-based constitutive relations, first at lower strain rates, for dislocation velocity control of the imposed plastic deformations and, then at higher rates, transitioning to nano-scale dislocation generation control by twinning or slip. For copper, there is the possibility of added-on slip dislocation displacements to be accounted for from the newly generated dislocations.

The core structure and recombination energy of a copper screw dislocation: a Peierls study

NASA Astrophysics Data System (ADS)

Szajewski, B. A.; Hunter, A.; Beyerlein, I. J.

2017-09-01

The recombination process of dislocations is central to cross-slip, and transmission through ?3 grain boundaries among other fundamental plastic deformation processes. Despite its importance, a detailed mechanistic understanding remains lacking. We apply a continuous dislocation model, inspired by Peierls and Nabarro, complete with an ab-initio computed ?-surface and continuous units of infinitesimal dislocation slip, towards computing the stress-dependent recombination path of both an isotropic and anisotropic Cu screw dislocation. Under no applied stress, our model reproduces the stacking fault width between Shockley partial dislocations as predicted by discrete linear elasticity. Upon application of a compressive Escaig stress, the two partial dislocations coalesce to a separation of ??. Upon increased loading the edge components of each partial dislocation recede, leaving behind a spread Peierls screw dislocation, indicating the recombined state. We demonstrate that the critical stress required to achieve the recombined state is independent of the shear modulus. Rather the critical recombination stress depends on an energy difference between an unstable fault energy (?) and the intrinsic stacking fault energy (?-?). We report recombination energies of ?W = 0.168 eV/Å and ?W = 0.084 eV/Å, respectively, for the Cu screw dislocation within isotropic and anisotropic media. We develop an analytic model which provides insight into our simulation results which compare favourably with other (similar) models.

Size dependence of yield strength simulated by a dislocation-density function dynamics approach

NASA Astrophysics Data System (ADS)

Leung, P. S. S.; Leung, H. S.; Cheng, B.; Ngan, A. H. W.

2015-04-01

The size dependence of the strength of nano- and micron-sized crystals is studied using a new simulation approach in which the dynamics of the density functions of dislocations are modeled. Since any quantity of dislocations can be represented by a density, this approach can handle large systems containing large quantities of dislocations, which may handicap discrete dislocation dynamics schemes due to the excessive computation time involved. For this reason, pillar sizes spanning a large range, from the sub-micron to micron regimes, can be simulated. The simulation results reveal the power-law relationship between strength and specimen size up to a certain size, beyond which the strength varies much more slowly with size. For specimens smaller than ∼4000b, their strength is found to be controlled by the dislocation depletion condition, in which the total dislocation density remains almost constant throughout the loading process. In specimens larger than ∼4000b, the initial dislocation distribution is of critical importance since the presence of dislocation entanglements is found to obstruct deformation in the neighboring regions within a distance of ∼2000b. This length scale suggests that the effects of dense dislocation clusters are greater in intermediate-sized specimens (e.g. 4000b and 8000b) than in larger specimens (e.g. 16 000b), according to the weakest-link concept.

Edge dislocations as sinks for sub-nanometric radiation induced defects in α-iron

NASA Astrophysics Data System (ADS)

Anento, N.; Malerba, L.; Serra, A.

2018-01-01

The role of edge dislocations as sinks for small radiation induced defects in bcc-Fe is investigated by means of atomistic computer simulation. In this work we investigate by Molecular Statics (T = 0K) the interaction between an immobile dislocation line and defect clusters of small sizes invisible experimentally. The study highlights in particular the anisotropy of the interaction and distinguishes between absorbed and trapped defects. When the considered defect intersects the dislocation glide plane and the distance from the dislocation line to the defect is on the range between 2 nm and 4 nm, either total or partial absorption of the cluster takes place leading to the formation of jogs. Residual defects produced during partial absorption pin the dislocation. By the calculation of stress-strain curves we have assessed the strength of those residues as obstacles for the motion of the dislocation, which is reflected on the unpinning stresses and the binding energies obtained. When the defect is outside this range, but on planes close to the dislocation glide plane, instead of absorption we have observed a capture process. Finally, with a view to introducing explicitly in kinetic Monte Carlo models a sink with the shape of a dislocation line, we have summarized our findings on a table presenting the most relevant parameters, which define the interaction of the dislocation with the defects considered.

Singular orientations and faceted motion of dislocations in body-centered cubic crystals.

PubMed

Kang, Keonwook; Bulatov, Vasily V; Cai, Wei

2012-09-18

Dislocation mobility is a fundamental material property that controls strength and ductility of crystals. An important measure of dislocation mobility is its Peierls stress, i.e., the minimal stress required to move a dislocation at zero temperature. Here we report that, in the body-centered cubic metal tantalum, the Peierls stress as a function of dislocation orientation exhibits fine structure with several singular orientations of high Peierls stress-stress spikes-surrounded by vicinal plateau regions. While the classical Peierls-Nabarro model captures the high Peierls stress of singular orientations, an extension that allows dislocations to bend is necessary to account for the plateau regions. Our results clarify the notion of dislocation kinks as meaningful only for orientations within the plateau regions vicinal to the Peierls stress spikes. These observations lead us to propose a Read-Shockley type classification of dislocation orientations into three distinct classes-special, vicinal, and general-with respect to their Peierls stress and motion mechanisms. We predict that dislocation loops expanding under stress at sufficiently low temperatures, should develop well defined facets corresponding to two special orientations of highest Peierls stress, the screw and the M111 orientations, both moving by kink mechanism. We propose that both the screw and the M111 dislocations are jointly responsible for the yield behavior of BCC metals at low temperatures.

Comparison of dislocation density tensor fields derived from discrete dislocation dynamics and crystal plasticity simulations of torsion

DOE PAGES

Jones, Reese E.; Zimmerman, Jonathan A.; Po, Giacomo; ...

2016-02-01

Accurate simulation of the plastic deformation of ductile metals is important to the design of structures and components to performance and failure criteria. Many techniques exist that address the length scales relevant to deformation processes, including dislocation dynamics (DD), which models the interaction and evolution of discrete dislocation line segments, and crystal plasticity (CP), which incorporates the crystalline nature and restricted motion of dislocations into a higher scale continuous field framework. While these two methods are conceptually related, there have been only nominal efforts focused at the global material response that use DD-generated information to enhance the fidelity of CPmore » models. To ascertain to what degree the predictions of CP are consistent with those of DD, we compare their global and microstructural response in a number of deformation modes. After using nominally homogeneous compression and shear deformation dislocation dynamics simulations to calibrate crystal plasticity ow rule parameters, we compare not only the system-level stress-strain response of prismatic wires in torsion but also the resulting geometrically necessary dislocation density fields. To establish a connection between explicit description of dislocations and the continuum assumed with crystal plasticity simulations we ascertain the minimum length-scale at which meaningful dislocation density fields appear. Furthermore, our results show that, for the case of torsion, that the two material models can produce comparable spatial dislocation density distributions.« less

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

Zhang, Guangming; Zhou, Zhangjian; Mo, Kun

An application of high-energy wide angle synchrotron X-ray diffraction to investigate the tensile deformation of 9Cr ferritic/martensitic (F/M) ODS steel is presented. With tensile loading and in-situ Xray exposure, the lattice strain development of matrix was determined. The lattice strain was found to decrease with increasing temperature, and the difference in Young's modulus of six different reflections at different temperatures reveals the temperature dependence of elastic anisotropy. The mean internal stress was calculated and compared with the applied stress, showing that the strengthening factor increased with increasing temperature, indicating that the oxide nanoparticles have a good strengthening impact at highmore » temperature. The dislocation density and character were also measured during tensile deformation. The dislocation density decreased with increasing of temperature due to the greater mobility of dislocation at high temperature. The dislocation character was determined by best-fit methods for different dislocation average contrasts with various levels of uncertainty. The results shows edge type dislocations dominate the plastic strain at room temperature (RT) and 300 C, while the screw type dislocations dominate at 600 C. The dominance of edge character in 9Cr F/M ODS steels at RT and 300 C is likely due to the pinning effect of nanoparticles for higher mobile edge dislocations when compared with screw dislocations, while the stronger screw type of dislocation structure at 600 C may be explained by the activated cross slip of screw segments.« less

Acetabular cup position and risk of dislocation in primary total hip arthroplasty.

PubMed

Seagrave, Kurt G; Troelsen, Anders; Malchau, Henrik; Husted, Henrik; Gromov, Kirill

2017-02-01

Background and purpose - Hip dislocation is one of the most common complications following total hip arthroplasty (THA). Several factors that affect dislocation have been identified, including acetabular cup positioning. Optimal values for cup inclination and anteversion are debatable. We performed a systematic review to describe the different methods for measuring cup placement, target zones for cup positioning, and the association between cup positioning and dislocation following primary THA. Methods - A systematic search of literature in the PubMed database was performed (January and February 2016) to identify articles that compared acetabular cup positioning and the risk of dislocation. Surgical approach and methods for measurement of cup angles were also considered. Results - 28 articles were determined to be relevant to our research question. Some articles demonstrated that cup positioning influenced postoperative dislocation whereas others did not. The majority of articles could not identify a statistically significant difference between dislocating and non-dislocating THA with regard to mean angles of cup anteversion and inclination. Most of the articles that assessed cup placement within the Lewinnek safe zone did not show a statistically significant reduction in dislocation rate. Alternative target ranges have been proposed by several authors. Interpretation - The Lewinnek safe zone could not be justified. It is difficult to draw broad conclusions regarding a definitive target zone for cup positioning in THA, due to variability between studies and the likely multifactorial nature of THA dislocation. Future studies comparing cup positioning and dislocation rate should investigate surgical approach separately. Standardized tools for measurement of cup positioning should be implemented to allow comparison between studies.

Acetabular cup position and risk of dislocation in primary total hip arthroplasty

PubMed Central

Seagrave, Kurt G; Troelsen, Anders; Malchau, Henrik; Husted, Henrik; Gromov, Kirill

2017-01-01

Background and purpose — Hip dislocation is one of the most common complications following total hip arthroplasty (THA). Several factors that affect dislocation have been identified, including acetabular cup positioning. Optimal values for cup inclination and anteversion are debatable. We performed a systematic review to describe the different methods for measuring cup placement, target zones for cup positioning, and the association between cup positioning and dislocation following primary THA. Methods — A systematic search of literature in the PubMed database was performed (January and February 2016) to identify articles that compared acetabular cup positioning and the risk of dislocation. Surgical approach and methods for measurement of cup angles were also considered. Results— 28 articles were determined to be relevant to our research question. Some articles demonstrated that cup positioning influenced postoperative dislocation whereas others did not. The majority of articles could not identify a statistically significant difference between dislocating and non-dislocating THA with regard to mean angles of cup anteversion and inclination. Most of the articles that assessed cup placement within the Lewinnek safe zone did not show a statistically significant reduction in dislocation rate. Alternative target ranges have been proposed by several authors. Interpretation— The Lewinnek safe zone could not be justified. It is difficult to draw broad conclusions regarding a definitive target zone for cup positioning in THA, due to variability between studies and the likely multifactorial nature of THA dislocation. Future studies comparing cup positioning and dislocation rate should investigate surgical approach separately. Standardized tools for measurement of cup positioning should be implemented to allow comparison between studies. PMID:27879150

Investigation into three dimensional hip anatomy in anterior dislocation after THA. Influence of the position of the hip rotation centre.

PubMed

Sariali, Elhadi; Klouche, Shahnez; Mamoudy, Patrick

2012-07-01

The components position is a major factor under the surgeon's control in determining the risk of dislocation post total hip arthroplasty. The aim of this study was to investigate the proper three-dimensional components position including the centre of rotation in the case of anterior dislocation. Among 1764 consecutive patients who underwent total hip arthroplasty using a direct anterior approach, 27 experienced anterior dislocation. The three-dimensional hip anatomy was investigated in 12 patients who were paired with 12 patients from the same initial cohort who did not experience dislocation and also with 36 control patients with osteoarthritis. A pelvic Cartesian referential was defined to perform the acetabular analysis. The coordinates were expressed as percentages of the pelvic width, height and depth. The anteversion angles were measured. The hip centre of rotation was significantly shifted medially and posteriorly in the dislocation group when compared to the non-dislocation group and also to the control group. There was no significant difference in component angular position between the dislocation-group and the non-dislocation group. However, the stem anteversion in the dislocation group was increased in comparison to the mean natural femoral anteversion of the control group. A medial and posterior displacement of the hip rotation centre was found to correlate to anterior dislocation post total hip arthoplasty. These results suggest the importance of an accurate restoration of the centre of rotation, whilst avoiding an excessive acetabular reaming which may induce a medial and a posterior displacement. III comparative non randomised. Copyright © 2011 Elsevier Ltd. All rights reserved.

Three-dimensional imaging of threading dislocations in GaN crystals using two-photon excitation photoluminescence

NASA Astrophysics Data System (ADS)

Tanikawa, Tomoyuki; Ohnishi, Kazuki; Kanoh, Masaya; Mukai, Takashi; Matsuoka, Takashi

2018-03-01

The three-dimensional imaging of threading dislocations in GaN films was demonstrated using two-photon excitation photoluminescence. The threading dislocations were shown as dark lines. The spatial resolutions near the surface were about 0.32 and 3.2 µm for the in-plane and depth directions, respectively. The threading dislocations with a density less than 108 cm-2 were resolved, although the aberration induced by the refractive index mismatch was observed. The decrease in threading dislocation density was clearly observed by increasing the GaN film thickness. This can be considered a novel method for characterizing threading dislocations in GaN films without any destructive preparations.

Multiphysical simulation analysis of the dislocation structure in germanium single crystals

NASA Astrophysics Data System (ADS)

Podkopaev, O. I.; Artemyev, V. V.; Smirnov, A. D.; Mamedov, V. M.; Sid'ko, A. P.; Kalaev, V. V.; Kravtsova, E. D.; Shimanskii, A. F.

2016-09-01

To grow high-quality germanium crystals is one of the most important problems of growth industry. The dislocation density is an important parameter of the quality of single crystals. The dislocation densities in germanium crystals 100 mm in diameter, which have various shapes of the side surface and are grown by the Czochralski technique, are experimentally measured. The crystal growth is numerically simulated using heat-transfer and hydrodynamics models and the Alexander-Haasen dislocation model in terms of the CGSim software package. A comparison of the experimental and calculated dislocation densities shows that the dislocation model can be applied to study lattice defects in germanium crystals and to improve their quality.

Ligamentous and capsular injuries to the metacarpophalangeal joints of the hand.

PubMed

Shah, Smiresh Suresh; Techy, Fernando; Mejia, Alfonso; Gonzalez, Mark H

2012-01-01

The mechanism of dorsal dislocation of the metacarpophalangeal (MCP) joint is with forced hyperextension of the joint and the main structure injured is the volar plate. A simple dislocation can be reduced by closed means whereas a complex dislocation cannot. Care must be taken not to put traction across the joint, which may cause the volar plate to slip into the joint, converting a simple dislocation into a complex dislocation. Volar dislocations are rare and mainly treated nonoperatively. Sagittal band injuries can be treated with extension splinting or surgical management with direct repair or reconstruction. A locked MCP joint can usually be treated with closed manipulation. This article discusses these injuries and management options.