Osteochondritis dissecans (OCD) of the knee in children is associated with more morbidity than previously recognized. Sixteen knees in 13 children with symptomatic OCD lesions in the knee diagnosed with MRI underwent arthroscopic fixation using polylactide biodegradable lag screws, after failing a minimum of 6 months conservative treatment. The mean age was 12.3 years; 14 lesions were in the medial condyle, two in the lateral condyle, and the mean area was 244 mm. Early physiotherapy was prescribed with no period of immobilization and the patients were followed for a mean of 27 months. One patient, who required a concomitant meniscal repair, developed a transient neurapraxia of the peroneal nerve but went on to full recovery. All patients but this one had returned to sport at 4-month follow-up. There was significant improvement in the knee function scores and all patients reported their knees as improved or much improved. We propose that simple arthroscopic fixation of OCD with SmartScrews is an effective treatment in the pediatric population leading to a rapid recovery of premorbid function.