The Golf Ball Sign: Arthroscopic Localization of an Osteochondritis Dissecans Lesion of the Knee

Abstract

We report on the arthroscopic treatment of a 12-year-old boy diagnosed with an osteochondral defect of the medial femoral condyle. He underwent arthroscopic fixation of the defect, and during the surgery, a blunt trocar was used to localize the lesion. The trocar created a transient dimpling effect on the cartilage overlying the osteochondral defect that resembled the surface of a golf ball. This "golf ball sign" then served as a visual guide during placement of a chondral dart. When present, it is believed that this sign can benefit arthroscopists by helping to improve intraoperative localization of an osteochondral defect.O steochondritis dissecans (OCD) of the knee is an acquired, idiopathic disease that affects the subchondral bone of the femur. The specific etiology remains unknown, but delamination and sequestration of the bone can result depending on the extent of the OCD lesion.1 The impact this has on the overlying cartilage can range from softening of the articular cartilage to development of an osteochondral flap and/or loose body formation. Depending on the size, location, and extent of articular cartilage involvement, the OCD lesion can cause significant discomfort and morbidity.Treatment options vary but can involve conservative, restricted weight-bearing options; operative fixation of a stable or unstable lesion; and/or loose body removal. Operative intervention is usually performed arthroscopically. A magnetic resonance imaging (MRI) study is often obtained beforehand during the clinical workup of the patient. The MRI study helps to determine the location of the lesion, which is verified by arthroscopic visualization of the defect. In early stages of the lesion, articular cartilage becomes soft and ballotable before developing overt fibrillations, fissures, or exposed bone.This particular case involves a 12-year-old boy with an OCD lesion who underwent operative fixation of his type IV lesion. We report about a technique used during the procedure, in which a blunt trocar was used to delineate the borders of the OCD lesion, which would later serve as a guide during the placement of our fixation. Surgical TechniqueThe patient was a 12-year-old boy who sustained a recent fall from standing that caused him to have continued left knee pain and swelling. He was unable to play his usual sports because of pain, clicking, and catching of the left knee. Radiographs obtained at the time of presentation showed an osteochondral defect involving the lateral aspect of the left medial femoral condyle. The plan for the patient was to restrict him from any sports, and he was to avoid any impact activities (running, jumping, and so on) for the next month until an MRI study was obtained. At his followup visit 5 weeks later, the MRI study showed a 10-mm oval lesion at the previously defined location, as well as the presence of subchondral cysts and fluid between the fragment and underlying bone (Fig 1). The articular cartilage remained free from any defects, and there was no evidence of a loose body within ...