What is the treatment for a deltoid ligament tear with a fractured distal fibula?

Treatment of Deltoid Ligament Tear with Fractured Distal Fibula

Surgical fixation of the distal fibular fracture without repair of the deltoid ligament is the recommended treatment for a deltoid ligament tear with a fractured distal fibula, provided anatomic reduction of the ankle mortise can be achieved.

Evaluation and Diagnosis

• Initial assessment should include weight-bearing radiographs (if possible) to evaluate stability
• A medial clear space of <4 mm confirms stability; >3 mm widening suggests deltoid ligament disruption 1, 2
• Gravity stress view is more reliable than manual stress view in evaluating suspected deltoid ligament disruption 1
• CT scan may be considered for complex injuries to improve diagnostic accuracy 3

Treatment Algorithm

Step 1: Assess Fracture Stability and Reduction

• Evaluate medial clear space on radiographs
• Check for signs of instability:
  • Medial tenderness, bruising, or swelling
  • Fibular fracture above the syndesmosis
  • Open fracture or high-energy injury 1

Step 2: Surgical Management

• Surgical fixation of the distal fibular fracture is indicated when:

  • Postreduction radial shortening >3 mm
  • Dorsal tilt >10°
  • Intra-articular displacement 3
  • Medial clear space widening >3 mm persists after attempted reduction 2

• Preferred surgical technique:

  • Open reduction and internal fixation (ORIF) of the fibular fracture
  • Anatomically contoured locking plates provide stable fixation 4
  • Deltoid ligament typically does not require repair if anatomic reduction of the ankle mortise is achieved 5, 2

Step 3: Post-operative Management

• Early mobilization and weight-bearing can be considered with stable fixation using locking plates 4
• Rigid immobilization (cast) is preferred over removable splints for displaced fractures 1, 3
• Radiographic follow-up at 3 weeks and at cessation of immobilization 3

Evidence for Non-Repair of Deltoid Ligament

The evidence strongly supports that repair of the deltoid ligament is unnecessary when proper reduction and fixation of the fibula is achieved:

• Harper's study showed 90% good or excellent results in patients treated without deltoid ligament repair 5
• Most patients had no pain during daily activities and no ankle instability
• Range of motion was within 15° of the uninjured ankle in 90% of patients 5

Important Considerations and Caveats

• Medial exploration is only indicated when:

  • Reduction of the lateral malleolus fails to reduce the talus within the ankle mortise 5
  • Persistent medial joint incongruency >3 mm on intraoperative radiographs 2

• Poor prognostic factors:

  • Associated osteochondral fractures (significantly worse outcomes) 2
  • Poor reduction of the lateral malleolus
  • Persistent widening of the medial joint >3 mm 2

• Potential complications of deltoid ligament repair:

  • Increased morbidity
  • Poor symptomatic and functional results in up to 41% of patients 6

In summary, the primary focus should be on anatomic reduction and stable fixation of the fibular fracture, which typically allows the deltoid ligament to heal without direct repair, leading to better functional outcomes and fewer complications.