Childhood Obesity is Associated With Osteochondritis Dissecans of the Knee, Ankle, and Elbow in Children and Adolescents.

BACKGROUND: Osteochondritis dissecans (OCD) is a joint disorder of the subchondral bone and articular cartilage whose association with obesity in children is not clearly known. The purpose of this study was to assess the magnitude of the association between childhood obesity and the occurrence of OCD of the knee, ankle, and elbow in children.

METHODS: A retrospective chart review of an integrated health system was performed on OCD patients aged 2 to 19 from 2007 to 2011, with over 1 million patients in this cohort. Lesion location, laterality, and all patient demographics were recorded. The body mass index (BMI) for each patient in the cohort was used to stratify patients into 5 weight classes (underweight, normal weight, overweight, moderately obese, and extremely obese) based on BMI-for-age. The associations between the 5 weight classes and OCD of the ankle, knee, and elbow were assessed using multiple logistic regression models to estimate odds ratios (OR) and 95% confidence intervals using multivariate analysis to adjust for patient demographic variables.

RESULTS: In total, 269 patients fit the inclusion criteria. Mean BMI, both absolute and percentile, was significantly higher for patients with OCD of the knee, elbow, and ankle than patients without OCD. In the multivariate analysis, extremely obese patients were found to have an increased OR of OCD for all patients, with an 86% increased risk of any OCD compared with normal weight patients. In addition, assessment by different types of OCD revealed that extremely obese patients had an increased OR of OCD of the elbow and ankle individually, with a 3.1 times increased OCD elbow risk and 3.0 times increased risk of ankle OCD in extremely obese patients. Although extremely obese patients did not have a statistically significant increased risk of knee OCD, moderately obese patients did have a 1.8 times increased risk of knee OCD as compared with normal weight children. There were no significantly different risks of any type of OCD seen in overweight or underweight patients as compared with normal weight patients.

CONCLUSIONS: In this population-based cohort study, extreme obesity is strongly associated with an increased risk of OCD overall and OCD of the elbow and ankle specifically. In addition, moderate obesity is associated with an increased risk of knee OCD. All types of OCD were also found to have a significantly greater average BMI when compared with patients without OCD.

LEVEL OF EVIDENCE: Level IV-descriptive epidemiology study.