What is the initial management approach for a patient presenting with symptoms suggestive of os trigonum?

Initial Management of Symptomatic Os Trigonum

The initial management of symptomatic os trigonum should follow a conservative approach including rest, NSAIDs, and physical therapy for at least 3 months before considering surgical intervention.

Clinical Presentation and Diagnosis

Symptomatic os trigonum typically presents with:

• Posterior ankle pain, especially during plantarflexion
• Pain that worsens with activities requiring forced plantarflexion
• Tenderness over the posterolateral aspect of the ankle
• Limited range of motion, particularly in plantarflexion
• Possible history of ankle sprain or chronic repetitive activities in plantarflexion

Diagnostic workup should include:

• Plain radiographs (lateral and oblique views) to identify the os trigonum
• Diagnostic injection with local anesthetic under fluoroscopic guidance to confirm the os trigonum as the pain source 1

Initial Management Algorithm

1. First-line treatment (0-3 months):

   • Activity modification (avoid activities requiring forced plantarflexion)
   • NSAIDs for pain and inflammation 2
   • Physical therapy focusing on:
     • Range of motion exercises
     • Strengthening of ankle musculature
     • Proprioceptive training
   • Consider corticosteroid injection under fluoroscopic guidance 1

2. Follow-up evaluation (after 4-6 weeks):

   • If symptoms improving: continue conservative management
   • If minimal improvement: consider second corticosteroid injection 1

3. Reassessment (at 3 months):

   • If conservative measures fail after 3 months, consider surgical consultation

Efficacy of Conservative Management

Conservative management with corticosteroid injections has shown good results, with approximately 84% of patients responding to this treatment 1. In a study of 19 athletes with symptomatic os trigonum, only 3 cases (16%) required surgical excision after failing conservative treatment 1.

Surgical Options (if conservative management fails)

When conservative treatment fails after at least 3 months, surgical excision of the os trigonum may be considered. Options include:

1. Arthroscopic excision:

   • Less invasive with quicker recovery
   • Typically performed through posterolateral portals 3, 4
   • Average return to protected weight-bearing in approximately 7 days 4
   • Full weight-bearing activities in about 24 days 4

2. Open excision:

   • Through a posterolateral approach
   • Higher risk of sural nerve injury (temporary in 10%, permanent in 10%) 5
   • Generally good outcomes with average AOFAS score of 87.6 points 5

Prognostic Factors

Patients with symptoms present for less than 2 years before surgery have significantly better outcomes (average AOFAS score of 90) compared to those with symptoms for more than 2 years (average score of 78) 5.

Common Pitfalls and Caveats

1. Misdiagnosis: Os trigonum syndrome can mimic other conditions such as Achilles tendinopathy, peroneal tendon disorders, or ankle sprains.

2. Delayed treatment: Prolonged symptoms (>2 years) before surgical intervention are associated with poorer outcomes 5.

3. Sural nerve injury: The most common complication of surgical excision is sural nerve injury, which can be temporary or permanent 5.

4. Inadequate rehabilitation: Following either conservative or surgical management, proper rehabilitation is essential to restore full function and prevent recurrence.

5. Return to activity too soon: Premature return to high-impact activities may lead to symptom recurrence or development of other ankle pathologies.

By following this structured approach to the management of symptomatic os trigonum, clinicians can optimize outcomes and minimize morbidity for affected patients.