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 ^2,4,6:

• 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:

• normal fusing apophysis: painless
• acute osteochondral fracture

In older patients consider:

• insufficiency fracture
• subchondral insufficiency fracture of the knee

• See also

• osteochondritis dissecans (general discussion)
  • osteochondritis dissecans of the ankle: talus
  • osteochondritis dissecans of the elbow: capitellum