Treatment of Lateral Malleolus Fractures
Initial radiographic evaluation with three standard views (anteroposterior, lateral, and mortise) is the cornerstone of diagnosis and treatment planning for lateral malleolus fractures, with stability being the most important criterion in determining treatment approach. 1
Initial Assessment
Imaging
- Apply Ottawa Ankle Rules (OAR) to determine need for radiographs:
- Inability to bear weight immediately after injury
- Point tenderness over the malleoli
- Inability to ambulate for 4 steps
- Standard radiographic protocol should include:
- Anteroposterior view
- Lateral view
- Mortise view (to include base of fifth metatarsal)
- Weight-bearing radiographs provide crucial information about stability when possible 1
Stability Assessment
- Medial clear space <4 mm confirms stability
- Signs of potential instability include:
- Medial tenderness, bruising, or swelling
- Fibular fracture above the syndesmosis
- Bi- or trimalleolar fractures
- Open fracture
- High-energy injury 1
Treatment Algorithm
Stable Non-displaced Fractures
- Conservative management:
- Short leg cast or removable boot
- Non-weight bearing or partial weight bearing for 4-6 weeks
- Progressive weight bearing as tolerated after initial period
Unstable or Displaced Fractures
- Surgical intervention with open reduction and internal fixation (ORIF) is indicated
- The lateral malleolus plays a key role in ankle stability and anatomical reduction is critical to prevent late degenerative arthritis 2
- Fixation options include:
- Plate and screw constructs
- Tension band wiring for small avulsion fractures
- Intramedullary fixation for certain fracture patterns
Special Considerations
- Associated injuries require additional attention:
- Medial malleolus fractures
- Posterior malleolus fractures
- Syndesmotic injuries
- Ligamentous injuries
- Spiral tibial shaft fractures may have associated malleolar fractures that require separate fixation 3
Post-operative Management
- Immobilization in cast or boot for 2-6 weeks depending on stability
- Progressive weight bearing based on radiographic evidence of healing
- Physical therapy to restore range of motion and strength
- Mean time to union is approximately 8.5 weeks 4
Potential Complications
- Nonunion (rare but possible, especially in:
- Male patients
- Supination fractures
- Weber type C fractures) 5
- Wound complications
- Malunion
- Post-traumatic arthritis
- Hardware irritation requiring removal (occurs in some cases) 4
Follow-up
- Regular radiographic assessment to monitor healing
- Functional outcome assessment using validated tools (e.g., Olerud-Molander Ankle Score)
- Consider hardware removal if symptomatic after fracture healing
Pitfalls to Avoid
- Failing to obtain adequate imaging of the ankle in tibial shaft fractures
- Inadequate reduction of the lateral malleolus leading to talar tilt and subsequent arthritis
- Overlooking associated injuries, particularly syndesmotic injuries
- Premature weight bearing in unstable fractures
Remember that anatomical reduction of the lateral malleolus is crucial for proper ankle joint alignment and function, as the talus position directly follows that of the lateral malleolus 2.