[Patellofemoral instability in children and adolescents]. / Patellofemorale Instabilität bei Kindern und Jugendlichen.

Patellofemoral instability is a common and clinically relevant disorder of multifactorial causes. Several concomitant problems such as genua valga, hyperlaxity, injuries or sports-related overuse may contribute to the development of instability and recurrent patellar dislocations. A thorough diagnosis is of paramount importance to delineate every contributing factor. This includes radiographic modalities and advanced imaging such as magnetic resonance imaging or torsional analyses. The authors recommend non-operative management (including physiotherapy, gait and proprioceptive training, orthoses) and, whenever non-operative measures fail, surgical patellar stabilization using, e.g. MPFL reconstruction.

Patellar instability: will my patella dislocate again?

PURPOSE OF REVIEW: The incidence of patellar instability in pediatric patients ranges is 50-100 in 100,000 patients per year. Risk of recurrent dislocations however has been cited from 8.6% to 88% depending on individual patient factors. This manuscript highlights the demographical, historical, and anatomic factors associated with recurrent patellar instability following a first-time patella dislocation in the pediatric population. RECENT FINDINGS: In recent years, various studies have focused on identifying risk factors for recurrent patellar instability following a primary patellar dislocation. A mix of patient factors, including age of first dislocation, patella alta, elevated tibial tubercle to trochlear groove and trochlear dysplasia have all been noted in the literature, which have helped to develop various scoring tools to predict recurrent dislocation following nonoperative treatment. SUMMARY: Risk of recurrent patellar instability in patients who have previously suffered a patellar dislocation can be due to many factors. These risk factors should be used and applied to a variety of risk scores in order to provide physicians and healthcare providers with a tool to counsel patients and families on their patellar redislocation risk and help guide further management.

Development of a Multivariable Model Based on Individual Risk Factors for Recurrent Lateral Patellar Dislocation.

BACKGROUND: Nonoperative treatment after first-time patellar dislocation is the standard of care. There is evidence that certain patients may be at high risk for recurrent instability. The aim of this study was to develop a multivariable model to guide management of patients based on their individual risk of recurrent dislocation. METHODS: A multivariable model was developed using 291 patients from 4 institutions to identify which patients were at higher risk for recurrent patellar dislocation within 2 years. This model was informed by a univariable logistic regression model developed to test factors based on the patient's history, physical examination, and imaging. The discriminatory ability of the model to classify who will or will not have a recurrent dislocation was measured using the area under the receiver operating characteristic curve (AUC). RESULTS: Age, a history of a contralateral patellar dislocation, skeletal immaturity, lateral patellar tilt, tibial tubercle-trochlear groove (TT-TG) distance, Insall-Salvati ratio, and trochlear dysplasia were the most important factors for recurrent patellar dislocation. Sex, mechanism of injury, Caton-Deschamps ratio, sulcus angle, inclination angle, and facet ratio were not factors for recurrent dislocation. The overall AUC for the multivariable model was 71% (95% confidence interval [CI]: 64.7% to 76.6%). CONCLUSIONS: Optimizing the management of lateral patellar dislocation will improve short-term disability from the dislocation and reduce the long-term risk of patellofemoral arthritis from repeated chondral injury. This multivariable model can identify patients who are at high risk for recurrent dislocation and would be good candidates for early operative treatment. Further validation of this model in a prospective cohort of patients will inform whether it can be used to determine the optimal treatment plan for patients presenting with an initial patellar dislocation. Until validation of the model is done with new patients, it should not be used in clinical practice. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Conservative versus repair of medial patellofemoral ligament for the treatment of patients with acute primary patellar dislocations: A systematic review and meta-analysis.

PURPOSE: The aim of this study was to perform a meta-analysis to compare the effects of repair of medial patellofemoral ligament (MPFL) and conservative treatment in patients with acute primary patellar dislocation (PPD). METHOD: The databases we used to search the studies included MEDILINE, EMBASE, and Cochrane registry of controlled clinical trials. Five randomized controlled studies comparing the effects of MPFL repair versus conservative treatment with 300 acute PPD patients were included in the present meta-analysis. Primary outcome was redislocation rate and secondary outcomes included Kujala score, percentage of excellent or good subjective opinion, Tegner activity score, and knee injury and osteoarthritis outcome score (KOOS; pain, symptoms, and activities of daily living). RESULTS: The outcome of the Kujala score was statistically significant between the two treatments and indicated that MPFL repair had a higher Kujala score than conservative treatment in patients with acute PPD. There was no significant difference between the two treatments regarding the redislocation rate (p = 0.32), percentage of excellent or good subjective opinion (p = 0.15), Tegner activity score (p = 0.24), and KOOS (p > 0.05). CONCLUSIONS: Based on the available data, MPFL repair did not reduce the risk of redislocation nor did it produce any significantly better outcome based on the clinical manifestations, including anterior knee pain and knee activities. Only the Kujala score was improved by MPFL repair compared with conservative treatment.

Conservative Versus Surgical Treatment for Primary Patellar Dislocation.

BACKGROUND: Primary patellar dislocation is often the initial manifestation of patellofemoral instability. Its long-term consequences can include recurrent dislocation and permanent dysfunction of the knee joint. There is no consensus on the optimal treatment of primary patellar dislocation in the relevant literature. The main prerequisite for a good long-term result is a realistic assessment of the risk of recurrent dislocation. METHODS: We carried out a systematic literature search in OvidSP (a search engine for full-text databases) and MEDLINE to identify suitable stratification models with respect to the risk of recurrent dislocation. RESULTS: In the ten studies included in the current analysis, eight risk factors for recurrence after primary patellar dislocation were identified. Six studies revealed a higher risk in younger patients, particularly those under 16 years of age. The sex of the patient had no clear influence. In two studies, bilateral instability was identified as a risk factor. Two anatomical risk factors-a high-riding patella (patella alta) and trochlear dysplasia-were found to have the greatest influence in six studies. In a metaanalysis of five studies, patella alta predisposed to recurrent dislocation with an odds ratio (OR) of 4.259 (95% confidence interval [1.9; 9.188]). Moreover, a pathologically increased tibial tuberosity to trochlear groove (TT-TG) distance and rupture of the medial patellofemoral ligament (MPFL) on the femoral side were associated with higher recurrence rates. Patients with multiple risk factors in combination had a very high risk of recurrence. CONCLUSION: The risk of recurrent dislocation after primary patellar dislocation is increased by a number of risk factors, and even more so when multiple such risk factors are present. Published stratification models enable an assessment of the individual risk profile. Patients at low risk can be managed conservatively; surgery should be considered for patients at high risk.

Does surgical treatment produce better outcomes than conservative treatment for acute primary patellar dislocations? A meta-analysis of 10 randomized controlled trials.

PURPOSE: The objective of this study was to conduct the latest meta-analysis of randomized controlled trials (RCTs) that compare clinical results between surgery and conservative therapy of acute primary patellar dislocation (APPD), focusing on medial patellofemoral ligament (MPFL) reconstruction. METHODS: We performed a literature search in Embase, The Cochrane Library, PubMed, and Medline to identify RCTs comparing APPD surgical treatment with conservative treatment from the establishment of each database to January 2019. The methodological quality of each RCT was assessed independently by the two authors through the Cochrane Collaboration's "Risk of Bias" tool. Mean differences of continuous variables and risk ratios of dichotomous variables were computed for the pooled data analyses. The I2 statistic and the χ2 test were used to evaluate heterogeneity, with the significance level set at I2 > 50% or P < 0.10. RESULTS: Ten RCTs with a sum of 569 patients (297 receiving surgical treatment and 263 receiving conservative treatment) met the inclusion criteria for meta-analysis. Pooled data analysis showed no statistical difference in the field of subluxation rate, Kujala score, patient satisfaction, and frequency of reoperation between the two groups. Tegner activity score and recurrent dislocation rate in the conservative group were significantly higher than those in the surgically treated group. CONCLUSIONS: Conservative treatment may produce better outcomes than surgery for APPD in consideration of Tegner activity score. However, in view of limited research available, the interpretation of the discoveries should be cautious. More convincing evidence is required to confirm the effect of MPFL reconstruction.

Surgical versus conservative treatment for first patellofemoral dislocations: a meta-analysis of clinical trials.

INTRODUCTION: The first approach for acute patellar dislocation is still a debated topic. The purpose of the present study was to perform a meta-analysis evaluating the outcomes of the surgical approach compared to the conservative treatments for primary acute patellar dislocation. We hypothesize that a prompt surgical treatment may lead to better outcomes in terms of re-dislocations and quality of life. METHODS: This meta-analysis was performed according to the PRISMA guidelines. All the prospective clinical trials comparing surgical and conservative treatment for first acute patellofemoral dislocation were included in this study. For the methodological quality assessment, the PEDro appraisal score was adopted. For the risk of publication bias, the funnel plot was performed. The statistical analysis was performed using the Review Manager Software 5.3 (The Nordic Cochrane Collaboration, Copenhagen). RESULTS: The funnel plot detected a low risk of publication bias. According to the PEDro score, the methodological quality assessment was good. Data from 654 patients were collected, undergoing a mean of 53.8 ± 48.4 month follow-up. A total of 311 patients (17.66 ± 4.1 years old) were analyzed in the surgery group and 291 patients (19.25 ± 4.5 years old) in the conservative ones. The mean Kujala score resulted in greater favor of the surgery group (MD: 9.99%; P = 0.006). The analysis of the comparison of re-dislocations resulted in favor of the surgery group (OR: 0.41; P < 0.0001). The analysis of the comparison of persistent joint instability resulted in favor of the surgery group (OR: 0.41; P < 0.0001). CONCLUSIONS: Data from the present study encourage a prompt surgical approach for the first patellofemoral dislocation.

Scoring system for optimal management of acute traumatic patellar dislocation: A multicenter study.

BACKGROUND: In first-time acute traumatic patellar dislocations, numerous anatomic and clinical factors are complicatedly associated and should be comprehensively considered for the optimal management of conservative or surgical intervention. The purpose of this study was to establish a scoring system, using a concept that is not complicated and easily used in clinic. METHODS: Of 131 first-time acute traumatic patellar dislocations, 81 patients (51 females, 30 males) with an average age of 19.6 (95%CI, 17.5-21.6) years and an average follow-up duration of 17.1 (95% CI, 12.3-21.9) months, who underwent conservative treatment after first-time dislocations, were reviewed. Based on the odds ratios applying logistic regression analysis, the scoring system was established. RESULTS: The scoring system (total: 10 points) had simple composition of age <20 (2 points), sports injury (1 points), hemarthrosis (1 points), and image findings of a bony fragment (3 points), lateral shift of the patella (1 points), and trochlear dysplasia (2 points). A threshold score of 6.5 was determined using the area under receiver operating characteristic curve of 0.893 (p < 0.0001). In logistic regression analysis, a score of ≥7 was shown to be a dominant factor for recurrence (OR = 27.1, p < 0.0001). Furthermore, the association between the score and recurrence risk was as follows: a score of ≤4 = low risk (1/21 cases, 5%); a score of 5-7 = medium risk (13/27 cases, 48%); a score of ≥8 = high risk (30/33 cases, 91%). CONCLUSIONS: Based on the simple scoring system, patients who scored ≥8 were considered suitable for surgical treatment because of the high rate of recurrence, whereas those who scored ≤4 were considered suitable for conservative treatment because of the low rate of recurrence.

Surgical treatment is better than non-surgical treatment for primary patellar dislocation: a meta-analysis of randomized controlled trials.

BACKGROUND: At present, the best treatment for primary patellar dislocation (PPD) has not been unified. Moreover, meta-analyses comparing the non-surgical and surgical treatments of PPD are lacking. Thus, we aimed to compare the clinical efficacy of surgical or non-surgical treatment of PPD. METHODS: Randomized controlled studies of surgical and non-surgical treatments of PPD from 1966 to 2018 were retrieved from the following databases: PubMed, EMBASE, Cochrane Library, Wanfang Database, China Knowledge Network, Google Scholar, and Weipu Database. We screened for literature that met the inclusion criteria and extracted useful data for our meta-analysis. RESULTS: Nine studies, involving 492 patients, met the inclusion criteria and were analyzed in this study. The recurrence rate of patellar dislocation in the surgical group was lower than that in the non-surgical group (P = 0.04]). Subgroup analysis according to the follow-up time showed that the Kujala score (P < 0.001) and lower recurrence rate of dislocation (P = 0.05) than the non-surgical group in the short term. Subgroup analysis according to surgical year showed that the surgical group get higher Kujala score (P < 0.001) and lower recurrence rate of dislocation (P = 0.01) than the non-surgical group in recent years. CONCLUSION: Surgical treatment can provide better clinical results in a short period of time, and patients may achieve good results within 10 years owing to the advances in surgical techniques and instruments. Thus, we recommend surgical treatment as the preferred treatment for primary patellar dislocation.

Treatment of First-time Patellar Dislocations and Evaluation of Risk Factors for Recurrent Patellar Instability.

Approximately one-third of skeletally mature patients with primary patellar dislocation will experience recurrent patellar instability over time. Because of the multifactorial combination of features contributing to overall stability of the patellofemoral joint, first-time patella dislocation presents a challenge to the treating physician. A detailed patient history, focused physical examination, and appropriate diagnostic imaging are essential for identifying risk factors for recurrent instability. Individual risk factors include young patient age, patella alta, trochlear dysplasia, and lateralization of the tibial tubercle. In combination these factors may pose even greater risk, and recently published predictive scoring models offer clinicians objective criteria to identify patients most at risk for recurrence. In patients at low risk of recurrence, nonoperative management can be effective, with "a la carte" surgical treatments gaining popularity in those with a higher than acceptable risk of re-dislocation.

Management of the first-time lateral patellar dislocation.

BACKGROUND: Little guidance exists on the management of the first-time patellar dislocation. The aim of this article was to review current guidance for management of this condition. METHODS: Recent meta-analyses, systematic reviews and current consensus documents relating to first-time patellar dislocation were sourced. An instructional lecture was then created and delivered at the acute knee injuries session at the British Orthopaedic Association 2019 annual conference, which was presented on behalf of the British Association for Surgery of the Knee. This article has been written based on this lecture. RESULTS: There is a paucity of literature relating to management of the first-time patellar dislocation. Many studies are of poor design, with inadequate follow-up, making it difficult to draw conclusions from them. However, based upon available information and consensus from working groups it is recommended that patients presenting with first-time dislocation should be assessed to ensure they have not sustained an alternative or associated injury that may require surgical intervention, be assessed and counselled for the risk of recurrent dislocation, and be referred for initial conservative treatment. Surgical stabilisation should be reserved for patients with recurrent instability. CONCLUSIONS: Most patients with a first-time patellar dislocation can be managed conservatively, having excluded associated injuries. Due to the poor quality of the literature, care must be taken interpreting the results of studies. It is clear that further research is required in this field.

A Meta-analysis of Surgical Versus Nonsurgical Treatment of Primary Patella Dislocation.

PURPOSE: To compare outcomes after surgery versus nonsurgical treatment in the management of primary lateral patellar dislocation (LPD) through a meta-analysis of randomized controlled trials (RCTs) in terms of redislocation rate and clinical outcome, investigating both short-term (<6 years) functional recovery and overall benefit over time (>6 years). METHODS: A systematic search of the literature was performed in November 2018. Risk of bias and quality of evidence were evaluated according to the Cochrane guidelines. RCTs investigating differences between surgery and nonsurgical treatment in primary LPD were included. The outcomes evaluated were redislocation rate, reinterventions, and Kujala score at short-, mid-, and long-term follow-up, with subanalyses for the pediatric population. RESULTS: We included 510 patients from 10 RCTs in the meta-analysis. Redislocation rate was 0.40 (0.25 to 0.66; P < .001) and 0.58 (0.29 to 1.15; P = .12) at the short- and mid-term follow-ups, respectively, and the risk ratio for the need for further operations at 6 to 9 months' follow-up was 0.14 (0.02 to 1.03; P = .05), all favoring surgery. Concerning the Kujala score, an advantage of the surgical approach of 10.2 points (1.6 to 18.7; P = .02) at short-term follow-up was seen, whereas long-term follow-up results were similar between the groups. The subanalysis of the pediatric population at heterogeneous follow-up confirmed a lower risk of recurrence in surgery, with a risk ratio of 0.60 (0.26 to 1.37; P = .22), although not significant. CONCLUSION: The literature documents a low number of high-level trials. The meta-analysis of RCTs underlined that the redislocation rate is higher with the nonsurgical approach compared with the surgical one. Moreover, when looking at the clinical outcome, more favorable findings were found with the surgical approach up to 6 years, whereas results seems to be similar at a longer follow-up after either surgical or nonsurgical treatment of primary LPD. LEVEL OF EVIDENCE: II, meta-analysis of level I and level II randomized clinical trials.

Surgical versus nonsurgical treatment of primary acute patellar dislocation: A systematic review and meta-analysis.

BACKGROUND: To systematically review the efficacy of surgical versus nonsurgical treatment for acute patellar dislocation. MATERIALS AND METHODS: PubMed, Cochrane, and Embase were searched up to February 12, 2019. After removing duplicates, preliminary screening, and reading the full texts, we finally selected 16 articles, including 11 randomized controlled trials and 5 cohort studies. The quality of the enrolled studies was evaluated by Jadad score or Newcastle-Ottawa scale. Meta-analyses were performed using odds ratio (OR) and standardized mean difference (SMD) as effect variables. The clinical parameters assessed included mean Kujala score, rate of redislocation, incidence of patellar subluxation, patient satisfaction, and visual analog scale (VAS) for pain. Evidence levels were determined using GRADE profile. RESULTS: The 16 included studies involved 918 cases, 418 in the surgical group and 500 in the nonsurgical group. The results of the meta-analysis showed higher mean Kujala score (SMD = 0.79, 95% confidence interval [CI] [0.3, 1.28], P = .002) and lower rate of redislocation (OR = 0.44, 95% CI [0.3, 0.63], P < .00001) in the surgical group than the nonsurgical group, but showed insignificant differences in the incidence of patellar subluxation (OR = 0.61, 95% CI [0.36, 1.03], P = .06), satisfaction of patients (OR = 1.44, 95% CI [0.64, 3.25], P = .38), and VAS (SMD = 0.84, 95% CI [-0.36, 9.03], P = .84). CONCLUSION: For patients with primary acute patellar dislocation, surgical treatment produces a higher mean Kujala score and a lower rate of redislocation than nonsurgical treatment.

Patellar complications after total knee arthroplasty.

Patellar complications are a source of poor total knee arthroplasty (TKA) outcomes that can require re-operation or prosthetic revision. Complications can occur with or without patellar resurfacing. The objective of this work is to answer six questions. (1) Have risk factors been identified, and can they help to prevent patellar complications? Patellar complications are associated with valgus, obesity, lateral retinacular release, and a thin patella. Selecting a prosthetic trochlea that will ensure proper patellar tracking is important. Resurfacing is an option if patellar thickness is greater than 12mm. (2) What is the best management of patellar fracture? The answer depends on two factors: (a) is the extensor apparatus disrupted? and (b) is the patellar implant loose? When either factor is present, revision surgery is needed (extensor apparatus reconstruction, prosthetic implant removal). When neither factor is present, non-operative treatment is the rule. (3) What is the best management of patellar instability? Rotational malalignment should be sought. In the event of femoral and/or tibial rotational malalignment, revision surgery should be considered. If not performed, options consist of medial patello-femoral ligament reconstruction and/or medialization tibial tuberosity osteotomy. (4) What is the best management of patellar clunk syndrome? When physiotherapy fails, arthroscopic resection can be considered. Recurrence can be treated by open resection, despite the higher risk of complications with this method. (5) What is the best management of anterior knee pain? The patient should be evaluated for causes amenable to treatment (fracture, instability, clunk, osteonecrosis, bony impingement on the prosthetic trochlea). If patellar resurfacing was performed, loosening should be considered. Otherwise, secondary resurfacing is appropriate only after convincingly ruling out other causes of pain. A painstaking evaluation is mandatory before repeat surgery for anterior knee pain: surgery is not in order in the 10% to 15% of cases that have no identifiable explanation. (6) What can be done to treat patellar defects? Available options include re-implantation (with bone grafting, cement, a biconvex implant, or a metallic frame), bone grafting without re-implantation, patellar reconstruction, patellectomy (best avoided due to the resulting loss of strength), osteotomy, and extensor apparatus allograft reconstruction. LEVEL OF EVIDENCE: V, expert opinion.

Which Technique Is Better for Treating Patellar Dislocation? A Systematic Review and Meta-analysis.

PURPOSE: To clarify the discrepancy in surgical options and present evidence to treat patellar dislocation by evaluating which of the techniques yields better improvement in stability and functional recovery for patellar dislocation. METHODS: The MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Web of Science, and Scopus electronic databases were searched for relevant articles comparing the outcomes of medial patellofemoral ligament (MPFL) treatment published up until August 2017. Data searching, extraction, analysis, and quality assessment were performed based on The Cochrane Collaboration guidelines. Clinical outcomes were evaluated using various outcome values in various techniques. For results with high heterogeneity, 95% prediction intervals (PIs) were also investigated. RESULTS: Eleven clinical studies were investigated. In patients with primary patellar dislocation, there were no significant differences in all evaluated outcomes between the conservative and surgical treatment groups. For patients with recurrent patellar dislocation, MPFL reconstruction was associated with a favorable Kujala score (mean difference, -8.91; 95% confidence interval, -14.05 to -3.77; I2 = 94%; 95% PI, -9.64 to -8.1) and Lysholm score (mean difference, -13.51; 95% confidence interval, -21.35 to -5.68; I2 = 96%; 95% PI, -14.86 to -12.16) when compared with soft tissue realignment surgery. CONCLUSIONS: Although surgical treatment of the MPFL for primary patellar dislocation is not superior to conservative treatment in restoring knee function and clinical outcomes, MPFL reconstruction is associated with more favorable clinical outcomes compared with medial soft tissue realignment surgery in patients with recurrent patellar dislocation. Double-bundle MPFL reconstruction seems to provide more favorable outcomes than single-bundle MPFL reconstruction, but this finding should be interpreted with caution because the evidence levels were low and were from only a few studies. LEVEL OF EVIDENCE: Level III, meta-analysis.

Operative Repair of Medial Patellofemoral Ligament Injury Versus Knee Brace in Children With an Acute First-Time Traumatic Patellar Dislocation: A Randomized Controlled Trial.

BACKGROUND: A lateral patellar dislocation (LPD) is the most common traumatic knee injury with hemarthrosis in children. The redislocation rate is high. Varying operative and nonoperative treatments have been advocated with no consensus on the best treatment. PURPOSE: (1) To evaluate if arthroscopic-assisted repair of the medial patellofemoral ligament (MPFL) in patients with an acute first-time traumatic LPD would reduce the recurrence rate and offer better objective/subjective knee function compared with a knee brace without repair. (2) To study the presence of anatomic patellar instability risk factors (APIFs) and their association with a redislocation. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: This was a prospective series of 74 skeletally immature patients aged 9 to 14 years (38 girls and 36 boys; mean age, 13.1 years) with a first-time traumatic LPD, with clinical examinations, radiographs, magnetic resonance imaging, and diagnostic arthroscopic surgery performed within 2 weeks of the index injury. The child was randomized to either (1) a knee brace (KB group) for 4 weeks and physical therapy or (2) arthroscopic-assisted repair (R group) of the MPFL with anchors, 4 weeks with a soft cast splint, and physical therapy. The follow-up time was 2 years. RESULTS: The redislocation rate was significantly lower in the R group than in the KB group at final follow-up: 8 patients (22%) versus 16 patients (43%), respectively ( P = .047). The Knee injury and Osteoarthritis Outcome Score for children sport/play and quality of life subscales had lower scores in the R group compared with the KB group; the significant differences were among those with redislocations. The mean Kujala score was excellent in the KB group (95.9) and good in the R group (90.9). An impaired Limb Symmetry Index (median, 83%) for concentric quadriceps torque at 90 deg/s was found only in the R group. Eighty-one percent of the study patients had ≥2 APIFs. Trochlear dysplasia (trochlear depth <3 mm) had the highest odds ratio for redislocations (2.35 [95% CI, 0.69-8.03]), with no significant association between APIFs and a redislocation. CONCLUSION: Operative repair of an MPFL injury in the acute phase in skeletally immature children with a primary traumatic LPD significantly reduced the redislocation rate but did not improve subjective or objective knee function compared with a knee brace without repair. The majority of the patients in both groups were satisfied with their knee function. There was a high representation of APIFs, which needs to be considered when evaluating the risk of redislocations. Registration: ISRCTN 39959729 (Current Controlled Trials).

Patellar malalignment treated with modified knee extension training: An electromyography study.

BACKGROUND: Patellar malalignment (PM) in most patients is ascribed to an imbalance of peripatellar soft tissue tension. RESEARCH QUESTION: Conservative treatment of PM initially with enforced training of the vastus medialis obliquus (VMO) has been widely applied. Non-operative techniques for treatment of PM require continuing development. METHODS: Thirty healthy young adults participated in the study. Two surface electromyography (EMG) electrodes were placed on the skin of the dominant lower thigh in each subject: one on the center of the muscle belly of the VMO and the other on the symmetric location of the vastus lateralis (VL). Maximum of knee extension action (from various angles of knee flexion to full extension) was initiated. Tests were conducted with knee flexion decreasing by 10° at each step. Each action was repeated three times, and the average value was calculated. The root mean square value of excited muscles in the EMG was recorded. The ratio of the VMO to the VL (VMO/VL) was used to indicate the effectiveness of the treatment. The knee position varied from 90° flexion initially, decreasing by 10° at each step. RESULTS: Nine sets of values were obtained. All extension actions were effective (VMO/VL >1; range, 1.23-1.35). The maximal value was observed at 60° flexion (VMO/VL = 1.35). Differences were not significant among the nine groups (p = 0.08, ANOVA). SIGNIFICANCE: Using the described knee extension training for conservative treatment of PM may be an effective alternative. The technique is simple, and the results of our experimental tests are encouraging. This method may become another popular and effective technique for treating PM.

Evaluation of the utility of teaching joint relocations using cadaveric specimens.

BACKGROUND: Like other procedural skills, the ability to relocate a joint is an important aspect of junior doctor education. Changes in the approach to teaching and learning from the traditional apprenticeship-style model have made the teaching of practical skills more difficult logistically. Workshops utilising cadaveric specimens offer a solution to this problem. METHODS: One hundred forty-six fourth year medical students were randomly divided into 5 groups. Each group received a different teaching intervention based on ankle, patella and hip relocation. The interventions consisted of online learning modules, instructional cards and workshops using skeleton models and cadaveric dislocation models. Following the intervention students were given a test containing multiple choice and true/false style questions. A 13-item 5-point Likert scale questionnaire was also delivered before and after the intervention. The data was analysed using one-way analysis of variance (ANOVA) and the Bonferroni post-hoc test. RESULTS: Compared to the instructional cards group, the other 4 groups showed a 10.8-19.2% improvement in total test score (p < 0.01) and an 18.4-25.3% improvement in self-reported understanding and confidence in performing joint relocations (P < 0.01). There was no significant difference in total test scores between groups exposed to cadaveric instruction on the relocation of one-, two- or all three- joints, nor any significant difference between all the cadaveric dislocation groups and the group receiving instruction on the skeleton model. CONCLUSION: The results of the present study suggest that workshops utilising cadaveric dislocation models are effective in teaching joint relocation. In addition, the finding that lower fidelity models may be of equal utility may provide institutions with flexibility of delivery needed to meet financial and resource constraints.

Does different duration of non-operative immobilization have an effect on the redislocation rate of primary patellar dislocation? A retrospective multicenter cohort study.

BACKGROUND: Immobilization devices such as plaster splints, casts and braces have been used for first time patellar dislocation (FTPD) in order to prevent redislocation. This study evaluates different non-operative immobilization regimes upon rates of redislocation. METHODS: A retrospective cohort study with a study population of 1366 in which 601 subjects under 30years with FTPD were included from three hospitals. Exclusion criteria were osteochondral fracture, ligament injury and subluxation. Subjects were divided into five groups; unknown/none, two weeks of brace, two weeks of brace followed by bandage, four weeks of brace and six weeks of brace with increasing of range of motion. Radiographs were evaluated for trochlear dysplasia (TD), patella alta, trochlear depth and growth zone. Crude analysis and logistic regression adjusted for radiographic assessments, age, gender and rehabilitation was done in STATA® with significance p≤0.05. RESULTS: Forty-five point eight percent were between 15 and 19years and 51.4% were male. One hundred sixty-three experienced redislocation (27.1%). Logistic regression was performed at 404 subjects and showed that rehabilitation, gender, TD, patella alta, and growth zone had no significant odds ratio (OR) on redislocation. The duration of brace demonstrated no significant OR in reducing redislocation. Subjects between 20 and 29years showed lower OR in redislocation (95% CI) of 0.27 (0.11; 0.64, p=0.003). CONCLUSION: This study demonstrated no difference in duration of brace treatment in reducing patella redislocation after FTPD. Rehabilitation and predisposal factors such as TD, trochlear depth, patella alta and open growth zone did not influence the redislocation rate. Increasing age reduced risk of redislocation.