Osteochondral Lesions of the Talus

Discussion

• although a traumatic etiology is believed to play a major role in production of these lesions, idiopathic osteonecrosis may be another factor;
• anterolateral lesions:
  • may result from impaction of talus on fibula as the dorsiflexed ankle is forced into inversion (see ankle sprain);
  • the vast majority are caused by trauma;
  • these lesions tend to be shallow;
• posteromedial lesions:
  • most of these lesions probably arised from trauma (but many will have an atraumatic etiology);
  • may result from impaction of posteromedial talus on tibia, as plantar flexion ankle is forced into inversion and exteranal rotation;
  • these lesions are deeper and cup shaped;
  • exam: palpate just posterior to the medial malleolus with the ankle dorsiflexed (may resemble pending rupture of posterior tib)

Exam

• joint line tenderness and effusion;

Radiographs

• osteochondral frx may be anterior or posterior to dome, requiring plantar or dorsiflexion of ankle to be visible on mortise view;
• if radiographs are negative consider repeat radiographs in 2-4 weeks;
• radiographic classification: (Berndt and Harty)
  • note: that radiographic findings may or may not correlate w/ arthroscopic findings nor prognosis;
    • I: small area of compression;
    • II: partially detached osteochondral lesion;
    • III: completely detached, non-displaced fragment;
    • IV: detached and displaced fragment;

Bone Scan

• usually not ordered until 8-12 weeks following diagnosis;
• a negative bone scan will r/o the diagnosis;
• if bone scan is positive then order either CT or MRI;

CT Scan

• offers more accurate staging of the lesion;

Treatments

Non Operative Treatment

• no evidence that non wt bearing cast offers improved results over wt bearing casts;
• no evidence that patients need to be immobilized if they are kept non wt bearing;

Operative Treatment

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Osteochondral Lesions of the Talus – Allograft Repair

 

• Arthroscopy of the Ankle:
  • osteochondral lesions of the talus can be debrided, and loose bodies and small osteochondral fragments can be removed;
  • use of non-invasive or invasive distraction improves access to joint and allows adequate debridement and curettage of bed;
  • anterolateral lesions can be addressed from the anterolateral portal;
  • in the study by Kumai, et al (1999), the authors noted good clinical results w/ arthroscopy and K wire drilling of the OCD lesions in patients who were younger than 50 years;
  • posteromedial lesions can be difficult to access;
    • w/ large fragments ORIF may be required, w/ osteotomy of the medial malleolus being required for exposure;
    • ORIF allows direct observation of the lesion and accurate repair;
    • w/ ORIF immobilization in a non wt bearing cast is required for 6-10 weeks

References

• Osteochondral fractures of the talus. A long-term follow-up.
• Osteochondral fractures of the dome of the talus.
• Osteochondral lesions of the talus.
• Osteochondritis dissecans of the dome of the talus. Computed tomography scanning in diagnosis and follow-up
• Osteochondritis dissecans of the talus (transchondral fractures of the talus): review of the literature and new surgical approach for medial dome lesions.
• Arthroscopic treatment of osteochondral lesions of the talus.
• Surgical treatment of transchondral talar-dome fractures (osteochondritis dissecans). Long-term follow-up.
• Transchondral fractures (osateochondritis dissecans) of the talus.
• Arthroscopic management of transchondral talar dome fractures (osteochondritis dissecans) and anterior impingement lesions of the ankle joint.
• Osteochondral lesions of the talus.
• Arthroscopic Drilling for the Treatment of Osteochondral Lesions of the Talus
• Nonoperatively managed stage 5 osteochondral talar lesions.