Lesion Size as a Predictor of Non-Operative Therapy Failure in Juvenile Osteochondritis Dissecans of the Knee

Abstract

Background: The primary challenge in juvenile osteochondritis dissecans of the knee management lies in the lack of definitive non-operative treatment criteria. The purpose of this study was to evaluate the predictive nature of the lesion size and to determine a lesion size cutoff point beyond which a patient’s likelihood of successful 3 month non-operative therapy significantly declines. Methods: 36 knees were retrospectively identified that met the inclusion criteria of stable JOCD lesions that received a 3 month non-operative therapy treatment consisting of either unloader bracing and/or activity restriction. The primary outcome of interest was improved clinical status at three months with accompanying MRI evidence of reossification. Continuous and categorical variables including lesion size were analyzed using logistic regression to ascertain the likelihood of a surgical intervention following a non-operative treatment regimen. Results: Following three months of non-operative treatment, 23 of the 36 knees (64%) had progression toward healing. The mean starting age of the patients with lesions that progressed toward healing was 10.4 years +/- 2.10 years and the mean age that required surgical referral was 12.4 years +/- 1.18 years (p = 0.002). The mean surface area of the lesions that demonstrated progression toward healing was 185.0mm2 +/- 103.7mm2, and the mean surface area of the lesions that did not progress toward healing and were referred for surgical management was 266.6mm2 +/- 95.5mm2 (p = 0.01). The mean lesion surface area cut point >250mm2 contained 13 knees. Of these 13 knees, 4 progressed toward healing (17.4% of the healing group), while 9 required surgical referral (69.2% of the surgery group) (OR = 6.84, 95% CI [1.17,39.8], p = 0.032). Conclusion: Increased lesion size and increased age were the strongest predictors of JOCD non-operative therapy failure. Stable lesions with a mean surface area that is > 250mm2 are at an increased risk for non-opperative failure and should be considered for direct surgical referral on a case by case basis.