Localization and Likelihood of Chondral and Osteochondral Lesions After Patellar Dislocation in Surgically Treated Children and Adolescents

BACKGROUND: Patellar dislocation is a common injury in children and adolescents. There is a lack of information about concomitant osteochondral lesions in these patients. HYPOTHESIS: We hypothesized that the likelihood of chondral or osteochondral lesions would increase with each prior patellar dislocation and that the appearance of lesions in surgically treated children and adolescents would be influenced by age, sex, injury mechanism, and body mass index (BMI). STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Inclusion criteria were (1) age <18 years, (2) surgical treatment with diagnostic arthroscopy of the knee including description of chondral and osteochondral lesions, and (3) maximum time period between the last patellar dislocation and presentation in our department of 6 weeks and maximum of 4 weeks between presentation and surgery. A total of 153 children (173 knees) with a mean age of 13.0 ± 2.1 years were included. All surgical reports and intraoperative arthroscopic imaging were analyzed retrospectively for the location and severity of lesions. The likelihood of lesions was calculated with multiple stepwise regression models regarding injury mechanism, number of dislocations, sex, age, physeal closure, and BMI. RESULTS: The regression model to predict femoral lesions was statistically significant (χ(2)[5] = 26.55; P < .001) and identified male sex, BMI ≥25, traumatic injury mechanism, and physeal closure as independent factors associated with the appearance of femoral lesions. The second regression model predicting the appearance of patellar lesions was also statistically significant (χ(2)[4] = 26.07; P < .001) and identified the traumatic injury mechanism as a single independent predictor for patellar lesions. CONCLUSION: BMI ≥25, male sex, and physeal closure were factors significantly associated with femoral chondral and osteochondral lesions in our cohort. In case of traumatic lateral patellar dislocation (LPD), the likelihood of patellar and femoral chondral and osteochondral lesions is significantly higher than in nontraumatic LPD. Early magnetic resonance imaging and surgical treatment should be considered in obese patients, male patients, and patients with physeal closure and after traumatic LPD.