ABSTRACT
INTRODUCTION: Isolated congenital ACLD is a rare condition with limited literature on the optimal management approach. At present, patients with instability symptoms have been managed with ACL reconstruction in case reports. We present a case report of symptomatic isolated congenital anterior cruciate ligament deficiency (ACLD) managed effectively with gradual correction of biplanar proximal tibial deformity alone. CASE PRESENTATION: This was a case of bilateral isolated congenital ACLD in a 15-year-old girl with chronic bilateral knee instability, bilateral mild genu valgum, and positive Lachman's tests. Biplanar tibial deformity was evident with a 50 proximal tibia valgus and a posterior tibial slope angle of 260 on the more symptomatic right knee. This was treated with a proximal tibial osteotomy and gradual correction with a hexapod frame using the CORA method. The right knee alignment was restored to normal. At 2-year post-surgery, her symptoms of instability had resolved, and there was a soft end point on the Lachman's test. CONCLUSION: We recommend that symptomatic isolated congenital ACLD be treated by correction of any existing bony deformities first, keeping in view of ACL reconstruction if instability persists thereafter. To date, there are no reports on correction of proximal tibial deformities as the first-line treatment in isolated congenital ACLD before consideration of ACL reconstruction. To the best of our knowledge, this is the first report of symptomatic isolated congenital ACLD managed with correction of the biplanar deformity of the proximal tibia alone. Our management strategy proved to be effective in the treatment of this patient's instability, with good post-operative outcomes.
ABSTRACT
BACKGROUND: Prophylactic pinning of the uninvolved side after unilateral slipped capital femoral epiphysis (SCFE) is controversial. The alpha angle, a measurement of femoral head-neck aspherity, was proposed as a predictor of progression of contralateral SCFE with a treatment threshold of greater than 50.5°. The aim of this study was to evaluate its validity in our cohort of patients. METHODS: A retrospective review of a 10-year series of patients who presented with unilateral SCFE was conducted. Minimum follow-up duration to identify contralateral progression was 18 months. Age, sex, ethnicity, and endocrinopathies were noted. Alpha angle measurements of the unaffected hip were performed by two independent observers. The average values of measurements were used for analysis. Univariate and multivariate logistic regression analyses were performed to identify predictors of contralateral progression. A receiver operating characteristic (ROC) curve was generated. RESULTS: There were 43 patients with unilateral SCFE. Seven patients (16.3%) developed contralateral SCFE. There were 31 males (72.1%) and 12 females (27.9%). The mean duration from index surgery to contralateral fixation was 43.9 weeks (range, 16.2 to 77 weeks). The mean alpha angle was significantly higher in the patients with contralateral progression (mean, 50.7°; standard deviation [SD], 5.4°; range, 43.8° to 58.5°) than in the patients without progression (mean, 43.0°; SD, 4.2°; range, 33.0° to 52.5°; p < 0.001). The alpha angle was also identified as a statistically significant predictor of contralateral progression on multivariate analysis (p = 0.02). The intraclass correlation coefficient for interobserver reliability was moderately strong at 0.76 (95% confidence interval, 0.55 to 0.87). The area under the ROC curve was 0.88. The treatment threshold of 50.5° had a sensitivity of 0.43, specificity of 0.94, and number needed to treat (NNT) of 2.7. The ideal treatment threshold derived from the ROC curve was 49.0°, which had a sensitivity of 0.71, specificity of 0.89, and an NNT of 1.7. CONCLUSIONS: Alpha angle is a potential predictor of contralateral hip involvement in children with SCFE who may benefit from prophylactic hip fixation. Results from our series suggest a treatment threshold be 49.0°. However, given the limited sample size and moderately strong interobserver reliability, larger studies are needed to validate our findings.