Osteochondral Lesions of the Talus

Epidemiology and Characteristics

• Most occur from an injury – may be minor
• Some may be secondary to localized AVN or metabolic problems

Location

• 70% medial and 30% lateral
• Usually are posteromedial and anterolateral
• Lateral are almost always traumatic
• Lateral tend to be unstable
• Medial more cystic and more stable
• 10% have a corresponding kissing lesion on the tibial plafond

Classification

Berndt & Hardy

1. Stage 1 – Subchondral fracture
2. Stage 2 – Partially detached fragment
3. Stage 3 – Detached but stable fragment
4. Stage 4 – Detached and unstable fragment – free floating

• This system is based on XR and 50% of OCDs are not seen on XR
• Newer MRI classifications (e.g., Bristol) use MRI
  • Incorporate bone oedema into their classification

Clinical Features

• Usually a history of injury, even if minor and some time ago
• Pain is the main feature
• Does not settle with non-operative modalities
• Synovitis can cause secondary impingement

Investigation

• Visible in 50% on plain X-rays

MRI

• Gold standard for quantifying lesion, degree of oedema, and other pathology

Management

Non-Operative

• May help – injection, physio, and activity modification
• Natural history of OCD is not yet known
• No current correlation with symptomatic OA
• RCT in 2000 (Tol et al.)
  • Showed improvement in 50% with non-operative and 80% with debridement
• Therefore, have a low threshold for arthroscopic debridement

Surgical Treatment

• Treatment of choice is arthroscopic debridement
• Chondral flaps and loose bodies
• Microfracture or curettage to bleeding bone for chondral defects
• Cartilage grafting (ACI, MACI, Plugs, Mosaicplasty, etc.)
  • Not proven in the ankle
  • Can be considered for larger areas of cartilage loss