Nissen, Carl

Background: Stable osteochondritis dissecans (OCD) lesions are primarily treated nonoperatively. Nonoperative treatment includes several recommendations, including the use of an unloader brace. However, little is known about the clinical effectiveness of unloader bracing and its influence on OCD healing, return to sports, and patient-reported outcomes (PROs). The purpose of this investigation was to evaluate the impact of unloader bracing on patients with stable medial femoral condyle (MFC) OCD lesions treated nonoperatively. Purpose: To investigate the influence of valgus unloader bracing on the success of treating stable MFC OCD with nonoperative treatment strategies. Study Design: Cohort study; Level of evidence, 2. Methods: The authors used a prospective cohort of patients receiving nonoperative care for stable MFC knee OCD lesions. The primary variable of interest was the efficacy of bracing. The primary outcomes were transition from nonoperative care to surgical intervention, return-to-play (RTP) clearance, and PROs. Bivariate testing was used to determine if there were differences between groups. Chi-square testing was used to determine if there were differences in rates of transition to surgery by group. The timing of the transition by each group was assessed using a Wilcoxon rank-sum test, given the nonparametric nature of the data. Kaplan-Meier survival analysis was used to calculate time at risk, incidence rate, and survival times for each group. Results: A total of 185 knees (bracing group: 123 [66.5%] knees; no-bracing group: 62 [33.5%] knees) were analyzed. Overall, 142 (76.8%) knees were successfully treated nonoperatively. Transition to surgery occurred in 43 (23.2%) knees. There were no differences in transition to surgery by groups, with no differences seen by group. Of the knees that did not transition to surgical care, 65 (71.4%) in the bracing group and 38 (74.5%) in the no-bracing group received RTP clearance ( P = .693). PRO scores were similar between the 2 groups at the time of RTP clearance. Conclusion: The inclusion of an unloader brace in the nonoperative treatment for stable MFC OCD lesions did not decrease the likelihood of patients undergoing surgical intervention or improve their PRO scores at the time of RTP clearance. Registration: NCT02771496 (ClinicalTrials.gov identifier).

Background: There are limited evidence-based guidelines to predict which osteochondritis dissecans (OCD) lesions will heal with nonoperative treatment. Purpose: To train a set of classification algorithms to predict nonoperative OCD healing while identifying new clinically meaningful predictors. Study Design: Case-control study; Level of evidence, 3. Methods: Patients with OCD of the knee with open physes undergoing nonoperative management were prospectively queried from the Research on OCD of the Knee (ROCK) cohort ( https://kneeocd.org ) in April 2022. Patients were included if they met the study criteria for nonoperative treatment success or failure. Nonoperative treatment success was defined as complete healing on magnetic resonance imaging (MRI) and total return to sports participation. Failure was defined as the crossover from nonoperative management to surgery at any point at or beyond the 3-month follow-up. If a patient did not meet one of these criteria, they were not included. Normalized lesion size, lesion location, patient characteristics, and symptoms were used as clinically relevant predictors. Results: A total of 64 patients were included, of whom 24 (37.5%) patients successfully healed with nonoperative management. Multivariate logistic regression revealed that a 1% increase in normalized lesion width was associated with an increase in the likelihood of nonoperative failure (odds ratio [OR], 1.41 [95% CI, 1.17-1.81]; P < .01). By contrast, lesions in the posterior sagittal zone (OR, 0.08 [95% CI, 0.009-0.43]; P < .01) or the medial-most coronal zone (for lesions of the medial femoral) and lateral-most coronal zone (for lesions of the lateral femoral condyle) on MRI (OR, 0.05 [95% CI, 0.004-0.44]; P < .01) were associated with a decrease in the likelihood of nonoperative treatment failure. Support vector machines had a cross-validated area under the receiver operating characteristic curve of 0.89 and a classification accuracy of 83.3%. Conclusion: Lesion location in the posterior aspect of the condyle on sagittal MRI and lesion location in the medial-most or lateral-most locations on coronal MRI were identified as statistically significant predictors of increased nonoperative treatment success on multivariate analysis. Machine learning models can predict which OCD lesions will heal with nonoperative management with superior accuracy compared with previously published models.