ABSTRACT: Osteochondritis dissecans (OCD) is a disorder of subchondral bone that commonly affects the knee.To (1) evaluate the rate of arthritis and knee arthroplasty in a population-based cohort of patients with OCD lesions treated nonoperatively and (2) evaluate factors that may predispose patients to knee osteoarthritis and arthroplasty.Case series; Level of evidence, 4.Eighty-six patients (mean age, 21.4 years) with OCD lesions treated nonoperatively were identified between 1976 and 2014. Information related to the diagnosis, laterality of lesion, details of treatment, and progression to arthritis was obtained from the medical record. Factors predictive of arthritis and arthroplasty (age, sex, body mass index [BMI], and lesion location) were examined.At a mean ± SD follow-up of 12.6 ± 9.8 years from diagnosis, 13 patients (15%) were diagnosed with arthritis, corresponding to a cumulative incidence of 5.0% at 5 years, 10.0% at 10 years, 20.0% at 25 years, and 30.0% at 35 years. The cumulative incidence of arthroplasty was 1.0% at 5 years, 3.0% at 10 years, 8.0% at 25 years, and 8.0% at 35 years. BMI at diagnosis greater than 25 kg/m2 (hazard ratio [HR], 15.4; 95% CI, 1.9-124.5), patellar OCD lesions (HR, 15.0; 95% CI, 1.3-345.3), and diagnosis as an adult (HR, 21.7; 95% CI, 2.7-176.3) were factors associated with an increased risk of arthritis.Arthritis after nonoperative treatment of OCD lesions is a challenging problem, with an estimated 30% cumulative incidence at 35 years after diagnosis. In contrast, the long-term rate of arthroplasty is low. BMI at diagnosis greater than 25 kg/m2 and patellar OCD lesions are predisposing factors for arthritis. Diagnosis of OCD as an adult was associated with a greater risk of arthritis.
