Does a bimalleolar ankle fracture require immediate surgery?

Bimalleolar Ankle Fractures: Surgical Timing

Bimalleolar ankle fractures generally require surgery, but not necessarily immediate (emergent) surgery—definitive surgical stabilization should ideally be performed within 24 hours of injury in hemodynamically stable patients to optimize outcomes and prevent complications. 1

Initial Assessment and Stabilization

The critical first step is determining whether the fracture is displaced and whether the patient is hemodynamically stable, as this dictates the entire treatment pathway. 1

Key Assessment Points:

• Evaluate for displacement and ankle mortise congruity on weightbearing radiographs if the patient can tolerate it, as rare nondisplaced bimalleolar fractures that remain stable under weightbearing may be candidates for nonoperative treatment 2
• Assess for open fracture, which requires urgent (not delayed) surgical debridement and antibiotic administration 3
• Check for associated neurovascular compromise or compartment syndrome, which would necessitate more urgent intervention 1
• Determine hemodynamic stability including respiratory function, coagulation status, and presence of other severe injuries 1

Surgical Timing Algorithm

For Hemodynamically Stable Patients with Displaced Fractures:

Proceed with definitive surgical fixation within 24 hours of injury using open reduction and internal fixation of both malleoli. 1 This timing:

• Reduces the risk of complications including fat embolism syndrome 1
• Allows for better resource allocation with a properly prepared operating room 3
• Does not require adherence to the outdated "six-hour rule" 3

The most common fixation techniques include modified tension band wiring or screw fixation for the medial malleolus and plate fixation (typically reconstruction plate) for the lateral malleolus, with syndesmotic screw placement if syndesmotic instability is present. 4, 5

For Hemodynamically Unstable Patients:

Implement damage control orthopedic surgery with temporary stabilization using external fixation or splinting, followed by delayed definitive fixation once the patient is stabilized. 1 Rushing unstable patients to definitive surgery can trigger massive inflammatory mediator release leading to multiple organ failure. 1

For Rare Nondisplaced, Weightbearing-Stable Fractures:

A small subset of bimalleolar fractures that are nondisplaced and remain stable on weightbearing radiographs (typically with oblique fracture patterns involving the anterior colliculus while preserving the posterior deep deltoid ligament origin) may be treated nonoperatively with functional bracing and weightbearing allowed. 2 However, this represents the exception rather than the rule and requires careful patient selection.

Critical Pitfalls to Avoid

• Do not delay surgery beyond 24 hours in stable patients, as this increases complication rates without providing benefit 1
• Do not assume all medial malleolar fractures require fixation—anterior collicular fractures may not need fixation if small and minimally displaced, whereas supracollicular fractures have significantly higher pain rates (28%) when not fixed 6
• Verify syndesmotic reduction intraoperatively with fluoroscopy or postoperative CT, as malreduction of the fibula in the tibial incisura is a common cause of poor outcomes 5
• For open fractures, use simple saline irrigation without additives (no soap or antiseptics), as these provide no additional benefit 3
• Administer appropriate antibiotics early—cefazolin or clindamycin for all open fractures, with addition of gram-negative coverage (preferably piperacillin-tazobactam) for Gustilo-Anderson Type II or III injuries 3

Expected Outcomes

With anatomic reconstruction of the ankle mortise and appropriate surgical timing, 75-89% of patients achieve good to excellent results. 5 Mean AOFAS scores typically exceed 90 out of 100 with proper surgical management. 4 However, the presence of initial dislocation, posterior malleolar involvement, cartilage damage, and syndesmotic disruption are negative prognostic factors associated with higher rates of post-traumatic arthritis. 5