What is the recommended treatment approach for a patient presenting with an osteochondroma in the ankle?

Treatment of Osteochondroma in the Ankle

Asymptomatic osteochondromas in the ankle can be initially observed, but surgical excision is indicated when symptomatic or showing growth, particularly in the distal tibia/fibula where delayed treatment risks progressive ankle deformity. 1

Initial Management Strategy

Observation vs. Intervention Decision Algorithm

Asymptomatic lesions:

• Initial observation is appropriate for incidentally discovered, asymptomatic osteochondromas 1
• However, ankle osteochondromas warrant closer surveillance than other locations due to unique complications 2, 3

Indications for surgical intervention:

• Pain or mechanical irritation 1
• Nerve compression or vascular compromise 4
• Evidence of growth or progression 1
• Limitation of ankle movement 5
• Posterior or anterior ankle impingement 6, 5
• Palpable mass causing symptoms 3

Surgical Treatment Approach

Timing Considerations

Critical distinction for ankle osteochondromas: Unlike osteochondromas in other locations where surgery can be delayed until skeletal maturity, distal tibia and fibula lesions require earlier intervention 2, 3. This is because:

• The expanding nature of these tumors causes plastic deformation of the tibia and fibula 3
• Progressive ankle deformity and pronation deformities develop if left untreated in skeletally immature patients 3
• Syndesmotic lesions can occur 2
• Fracture risk exists due to persistent ankle motion 6

In skeletally immature patients with symptoms: Partial excision preserving the physis may be necessary despite higher recurrence rates (the study showed 4 recurrences in 19 patients, with 3 symptomatic) 3. Close follow-up is mandatory in these cases 3.

In skeletally mature patients: Complete excision is the definitive treatment 1, 3

Surgical Technique

Standard approach:

• Complete excision/curettage for symptomatic lesions 1
• Wide surgical excision is recommended for lesions with concerning features 1
• Posterior talar osteochondromas with a stalk should be treated surgically before fracture complications occur 6

Surgical adjuvants (high-speed burr, cryotherapy) can be used but are optional 1

Location-Specific Considerations

Posterior talus: These lesions are particularly prone to fracture due to persistent ankle motion and should be excised proactively, especially when a stalk is present 6

Anterior/anteromedial talus: Rarer location that causes ankle impingement and movement limitation 5

Distal tibia (lateral malleolus): More often symptomatic than fibular lesions, typically presenting with ankle pain and palpable mass 3

Distal fibula: Less commonly symptomatic but still requires treatment to prevent deformity 3

Expected Outcomes

Functional results: All surgically treated patients in the highest quality ankle-specific study achieved 100% Musculoskeletal Tumor Society scores with pain-free, symmetrical, unrestricted ankle motion 3

Remodeling: Partial remodeling of tibia and fibula occurs postoperatively, most complete in younger patients, though pronation deformities do not change after excision 3

Complications and Pitfalls

Surgical complications to monitor:

• Recurrence (higher with partial excision in immature patients) 3
• Sural neuroma 3
• Growth arrest of distal tibia/fibula if physis is injured 3
• Superficial wound infection 3

Critical caveat: Patients with hereditary multiple exostoses require close follow-up due to increased risk of secondary chondrosarcoma development 1, 7. Pain at the site of a cartilaginous lesion may indicate malignant transformation 8.

Surveillance Protocol

For benign lesions post-excision:

• Physical examination, imaging of the lesion, and chest radiograph every 6-12 months for 2 years, then yearly 1

For lesions with malignant transformation:

• More intensive surveillance with cross-sectional imaging and chest imaging every 3-6 months for 5 years 1

When to Suspect Malignant Transformation

Red flags requiring biopsy consideration:

• New onset pain in a previously stable lesion 8
• Continued growth after skeletal maturity 4
• Cartilage cap thickness >2 cm in adults 4

If low-grade peripheral chondrosarcoma is confirmed: Complete removal with normal tissue margins is required 1. Higher-grade lesions require wide surgical excision with margins of at least 2 mm 1.