Figure 1. Anteroposterior radiographic view of left knee
Figure 2. Magnetic resonance imaging of same knee.
A 38-year-old woman presents to the office with a 2-month history of left knee pain with bending and squatting. She denies a known injury or precipitating event that may explain the pain. She describes the knee as having occasional catching and giving way while walking. On physical examination, she has pain to palpation over the anterior medial knee and no effusion. Her knee pain is made worse with deep knee flexion. Radiography (Figure 1) reveals a cyst on the medial femoral condyle and no arthritic changes. Magnetic resonance imaging of the left knee (Figure 2) shows an osteochondral lesion with cyst formation at the medial femoral notch measuring 2 x 2.5-cm. This is a full-thickness osteochondral defect with concavity of the articular surface.
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The most common location for an osteochondral (OCD) lesion is in the medial femoral condyle, which accounts for 75% of all lesions. The severity of an OCD lesion ranges from early softening of the articular cartilage, early cartilage separation, and detachment and loose body formation of the osteochondral lesion.1,2
Magnetic resonance imaging (MRI) is the diagnostic modality of choice for identifying OCD lesions and determining the most appropriate treatment. Most adult forms of OCD stem from asymptomatic or untreated juvenile OCD. Adult OCD lesions often require surgical intervention as the articular cartilage has a poor ability to heal itself. For small unrepairable lesions, an arthroscopic debridement with loose body removal and/or microfracture is generally recommended. For larger unstable lesions, treatment generally includes fragment removal and osteochondral allograft, autograft, or autologous chondrocyte implantation. For smaller lesions (<2 cm2), osteochondral autograft can be used. For larger lesions with bone loss, osteochondral allograft is recommended. Autologous chondrocyte implementation is not recommended for extensive bone loss that requires restoration.1,2
1. Friel NA, Bajaj S, Cole BJ. Articular cartilage injury and adult OCD: treatment options and decision making. In: Scott WN, ed. Insall & Scott Surgery of the Knee. Elsevier; 2012;5:153-162.
2. Sherman SL, Garrity J, Bauer K, Cook J, Stannard J, Bugbee W. Fresh osteochondral allograft transplantation for the knee: current concepts. J Am Acad Orthop Surg. 2014;22(2):121-133. doi:10.5435/JAAOS-22-02-121