We report two cases of osteochondritis dissecans (OCD) in identical twin male badminton players. The younger brother presented at the age of 15 years complaining of a two-year history of right knee pain during sports activity. Physical examination showed a positive result in the patella grinding test, but no range of motion limitation. Plain radiography showed that the lateral femoral groove had irregularity and a radiolucent region, and a diagnosis of OCD was made on the basis of magnetic resonance imaging (MRI). Arthroscopy demonstrated softening of the OCD lesion and partial cracking of the cartilage. The OCD lesion was fixed using bone strips. Five months after surgery, MRI demonstrated almost total disappearance of the lesion, and the patient returned to his original sports activity. The elder brother presented at the age of 16 years with a three-month history of left knee pain during sports. Physical examination revealed only mild tenderness of the patellofemoral joint. Plain radiography and MRI showed OCD in the lateral femoral groove, and arthroscopy demonstrated the lesion but no cracking of the cartilage. As had been the case for the younger brother, surgery was performed using bone strips. Because the lesion appeared to show good remodeling into normal bone on MRI at three months after surgery, the patient returned to his original level of sport. Although familial incidence of OCD is not unusual, cases in identical twins are very rare. The similarities of both site and onset timing of these OCD lesions suggest that some genetic factor may contribute to the cause of OCD other than overloading due to repetitive and strong sports activity. Also, our clinical results indicate that fixation with bone strips is a useful therapeutic option for OCD in the femoral groove to facilitate a prompt return to sports activity.
