What is the initial treatment approach for a small focus of heterotopic ossification (HO) within the Achilles tendon?

Initial Management of Small Heterotopic Ossification in the Achilles Tendon

For a small focus of heterotopic ossification (HO) within the distal Achilles tendon, initial treatment should be conservative with activity modification, eccentric strengthening exercises, and NSAIDs for pain control, while avoiding corticosteroid injections that could weaken the tendon and predispose to rupture. 1

Conservative Treatment Approach

Activity Modification

• Reduce activities that cause pain to prevent ongoing damage, while continuing activities that don't worsen pain 1
• Open-backed shoes can reduce pressure on the affected area 1
• Heel lifts or orthoses can help unload the tendon 1

Exercise-Based Therapy

• Eccentric strengthening exercises are the gold standard treatment, stimulating collagen production and guiding normal alignment of newly formed collagen fibers 1
• Stretching exercises for the gastrocnemius-soleus complex improve flexibility and reduce tension on the tendon 1

Pain Management

• NSAIDs (oral or topical) are effective for short-term pain relief, with topical formulations having fewer systemic side effects 1
• Cryotherapy provides short-term pain relief by reducing tissue metabolism 1
• Avoid corticosteroid injections into the Achilles tendon, as they may inhibit healing, reduce tensile strength, and predispose to spontaneous rupture 1

Monitoring and Follow-Up

Treatment Duration

• Continue initial conservative treatment for 6-8 weeks before considering more aggressive interventions 1
• If improvement occurs, continue treatments until symptoms resolve 1
• Consider referral to a specialist if no improvement occurs after 6-8 weeks of conservative treatment 1

Imaging Considerations

• Plain radiographs are most sensitive for detecting heterotopic ossification compared to MRI 2
• Three-phase bone scan can identify the inflammatory component of HO in early phases, with delayed images demonstrating increased tracer uptake due to bone formation 2

Important Clinical Pitfalls

Biomechanical Assessment

• Evaluate for anatomic deformities such as forefoot and heel varus, excessive pes planus, or foot pronation, as these biomechanical factors often contribute to the development and persistence of Achilles pathology 1

Surgical Timing Considerations

• For small, asymptomatic HO lesions, surgery is generally not indicated initially 3, 4
• If surgical resection becomes necessary, HO is likely to recur and possibly progress if resection is undertaken before the lesion has become mature 5
• Serial quantitative bone scans can be used to assess maturity before considering surgical intervention 5

Prophylaxis Options (If Indicated)

• Nonsteroidal anti-inflammatory drugs (such as indomethacin), diphosphonates, or local radiation therapy may be used for HO prophylaxis in high-risk situations 5, 6
• However, for small existing lesions, conservative management remains first-line 1