osteochondritis dissecans of the knee

Osteochondritis dissecans (OCD) most commonly affects the knee. See osteochondritis dissecans article for a general discussion.

Pathology

Location

The condition occurs bilaterally in 25% of cases, and has a characteristic distribution :

  • medial condyle: ~78.5% (range 70-85%)
    • "classic" lateral surface of the medial condyle: ~70%
    • this can be remembered by the mnemonic "LAME"; Lateral Aspect of the Medial Epicondyle
  • lateral condyle: 15%
    • inferocentral portion: 13%
    • anterior surface: 2%
  • patella: ~7.5% (range 5-10%)
    • typically inferomedial
  • patellofemoral groove (femoral trochlea): <1%
  • weight-bearing surface of the tibia: uncommon

Radiographic features

These are discussed in the general article on osteochondritis dissecans.

Differential diagnosis

The differential diagnosis includes:

In older patients consider: