Overview
This guide covers fixation of the lateral malleolus (distal fibula) and the medial malleolus in bimalleolar ankle fractures. The aims are an anatomic reduction and restoration of fibular length, so that the ankle mortise is restored.
Order of Fixation
Routine: Reduce and fix the lateral malleolus (fibula) first, then the medial malleolus.
Exception: In a severely comminuted lateral malleolus, the fibula may be overreduced in the coronal plane, which prevents anatomic reduction of the medial malleolus. In that situation, it may be better to fix the medial malleolus first.
Part A — Fixation of the Lateral Malleolus
Approach
Use a lateral longitudinal incision over the lateral malleolus and distal fibular shaft. Protect the superficial peroneal nerve.
Alternative: A posterolateral incision with a posterior antiglide plate.
It allows bicortical distal fixation from posterior to anterior.
The incision does not lie directly over a lateral implant.
It makes direct exposure of the syndesmosis more difficult.
Expose the fibula extraperiosteally.
Fixation Options by Fracture Pattern
Pattern | Fixation |
|---|---|
Sufficiently oblique, good bone stock, no comminution | One or two anterior-to-posterior lag screws, about 1 cm apart |
Transverse fracture | Intramedullary device (titanium elastic nail, interlocking fibular rod, etc.) |
Below the plafond, small distal fragment, good bone stock | Intramedullary malleolar screw (usually 2.7–3.5 mm; rarely 4.5 mm in large patients) |
Above the syndesmosis | Small-fragment one-third tubular plate; 3.5 mm DCP in large patients or more proximal fractures |
Any pattern (alternative) | Precontoured periarticular locking plates |
Surgical Steps
Lag screw fixation: Screw length is critical. The screws must engage the posterior cortex but must not protrude far enough to encroach on the peroneal tendon sheaths.
Intramedullary fixation:
Expose the tip of the lateral malleolus by splitting the calcaneofibular ligament fibers longitudinally.
Pass the device across the fracture into the medullary canal of the proximal fragment.
Pitfall: A straight implant can tilt the lateral malleolus toward the talus, which narrows the mortise and reduces motion. Prevent this by contouring the rod.
Malleolar screw: Angling the screw slightly lets it gain purchase in the medial fibular cortex above the fracture.
Plate fixation:
The plate can neutralize lag screw fixation or bridge a comminuted segment.
As a general rule, place three cortical screws above the fracture and two or three below it.
Below the plafond, use unicortical cancellous screws.
Precontoured fixed-angle distal fibular locking plates provide extra distal fixation options, at the cost of more implant prominence.
Make sure fibular length and anatomic reduction are maintained.
If needed, fix the syndesmosis. A syndesmotic screw can be passed through one of the plate holes.
Part B — Fixation of the Medial Malleolus
Approach
Use an anteromedial incision that starts about 2 cm proximal to the fracture line, curves distally and slightly posteriorly, and ends about 2 cm distal to the tip of the medial malleolus.
Advantages:
The posterior tibial tendon and its sheath are less likely to be injured.
The articular surface, particularly the anteromedial joint, is visible, so alignment can be checked and any impaction can be treated.
Disadvantage: The incision cannot be extended distally if associated foot injuries need treatment.
Surgical Steps
Handle the skin gently and reflect the flap together with its subcutaneous tissue. The skin here has a poor blood supply and is prone to slough.
Protect the greater saphenous vein and its accompanying nerve.
The distal fragment is usually displaced distally and anteriorly, and a fold of periosteum is often trapped in the fracture. Remove it sharply to expose the fracture serrations.
Debride small loose osteochondral fragments. Preserve large osteochondral fragments and support them with bone graft.
Reduce the malleolus with a bone-holding clamp or pointed reduction tenaculum. Hold it temporarily with two 1.6–2 mm smooth K-wires.
Check the reduction on AP and lateral radiographs. If it is satisfactory, remove one K-wire and insert a screw, then exchange the second K-wire for a screw. One or two screws are usually used. A long pelvic drill bit is needed for bicortical lag screws.
Inspect the joint, especially the superomedial corner, to make sure no screw has entered the articular surface.
Confirm screw position and reduction radiographically.
Special situations:
Very small or comminuted fragments: use multiple K-wires, minifragment screws, or tension band wiring.
Large vertical fractures with proximal comminution: use a buttress plate (one-third tubular or low-profile minifragment plate) to prevent loss of reduction.
Take great care with bulky implants in this area of poor skin coverage, to avoid wound complications.
Postoperative Care
Initial: Posterior plaster splint with the ankle in neutral, plus elevation.
Good bone quality and secure fixation: At the first postoperative visit, change to a removable splint or fracture boot and begin range-of-motion exercises.
Weight bearing: Usually restricted for 6 weeks if there is no syndesmotic injury. Then start partial weight bearing and progress according to healing. Studies evaluating earlier weight bearing are ongoing.
Compromised fixation (poor skin, poor bone quality, diabetes, neuropathy, etc.): Short-leg cast, with no weight bearing until healing is progressing well (8–12 weeks). Then a short-leg walking boot, with progressive weight bearing.
Reference
Rudloff MI. Fractures of the lower extremity. In: Azar FM, Sawyer JR, Throckmorton TW, eds. Campbell's Operative Orthopaedics. 15th ed. Philadelphia: Elsevier; 2026. Chapter 59, Techniques 59.1–59.2.