Ankle Fracture ORIF - Weber B/C Fibula with Medial Malleolus

Indications for surgery. Operate when the ankle mortise is, or is at risk of becoming, incongruent: - Talar shift on weight-bearing or stress radiographs — a medial clear space greater than 4mm.

• A bimalleolar or trimalleolar fracture pattern (inherently unstable).
• A bimalleolar equivalent injury — a lateral malleolar fracture with a deltoid rupture and a medial clear space greater than 4mm.
• Weber B with a medial injury (malleolar fracture or deltoid rupture) or a syndesmotic injury.
• Weber C (fracture above the syndesmosis) — typically unstable, almost always needing surgery.
• A posterior malleolar fragment involving greater than 25 percent of the plafond, or with greater than 2mm of articular step-off.
• An isolated, displaced Weber B in a young active patient where anatomic reduction is the goal. Weber type alone does not define stability. A Weber B can be stable or unstable depending on the medial structures and the syndesmosis, and even a Weber A is unstable if there is an associated medial injury. Assess stability systematically across four axes — the lateral fibula, the medial structures (malleolus versus deltoid), the syndesmosis, and the posterior malleolus. Soft tissue timing is as important as technique. If the soft tissue envelope is compromised (severe swelling, fracture blisters, skin compromise), delay definitive fixation until the wrinkle sign appears — typically 7-14 days — while holding the fracture reduced in a well-padded posterior splint with strict elevation. Exceptions requiring urgent surgery are an open fracture, compartment syndrome, skin tenting or vascular compromise. Operating through compromised soft tissues drives wound complications up to 10-30 percent, especially over the medial malleolus in diabetics and peripheral vascular disease. Consent specifically for wound complications and infection (highest over the medial malleolus), sensory nerve injury (saphenous, sural, superficial peroneal) and painful neuroma, hardware prominence and the possible need for removal, post-traumatic arthritis developing in 15-30 percent at 10-20 years despite anatomic reduction, and the small risk of deep venous thrombosis. Setup. Supine on a radiolucent table with a bump under the ipsilateral hip to internally rotate the leg 15-20 degrees (bringing the posterolateral fibula anterior for exposure), the knee flexed 30-45 degrees over a triangle or the break in the table, and the C-arm brought in from the contralateral side for AP, mortise and lateral views. A thigh tourniquet improves visualization but should be released before closure; consider a tourniquet-free technique when the soft tissues are marginal. Have the contralateral ankle images available — they are the template for fibular length.

The goal is anatomic restoration of the ankle mortise. The fibula determines mortise alignment, so the sequence is: expose and fix the fibula first, then assess and fix the syndesmosis, then expose and fix the medial malleolus, address the posterior malleolus if indicated, and confirm a perfect mortise on fluoroscopy. The exposures are laid out as the first steps of each side.

View larger

Fixation choices at a glance

Rehabilitation | Phase | Timing | Immobilisation / weight-bearing | Therapy focus | |-------|--------|--------------------------------|---------------| | 1 | 0-2 weeks | Posterior splint, strict non-weight-bearing, strict elevation | Finger and toe active range of motion only; DVT prophylaxis per protocol | | 2 | 2-6 weeks | Removable CAM boot or short-leg cast, still non-weight-bearing | Wound check and suture removal at 14 days; begin ankle range-of-motion out of the boot | | 3 | 6-10 weeks | Weight-bearing as tolerated in the boot if callus forms | Progressive weight-bearing, physiotherapy for ROM and strengthening | | 4 | 10-12 weeks+ | Wean from the boot into a supportive shoe | Remove quadricortical syndesmotic screws if used (tricortical and suture buttons stay) | | 5 | 4-6 months | Normal footwear | Return to impact activity and sport when strength and ROM are adequate | Most patients return to desk work around 6 weeks and to heavy manual work by 4-6 months. Around 75-85 percent report good-to-excellent outcomes when anatomic reduction is achieved; roughly 20-30 percent have some residual pain or stiffness, and post-traumatic arthritis develops in 15-30 percent at 10-20 years despite an anatomic reduction. Monitor with annual radiographs for the first 2-3 years. Complications

Ankle mortise anatomy. The tibiotalar joint is a highly congruent modified hinge. The tibial plafond (with its medial malleolus and anterior and posterior lips), the distal fibula forming the lateral wall, and the trapezoidal talus — wider anteriorly by 10-15 percent, which stabilizes the mortise in dorsiflexion — together define the mortise. The critical radiographic measurements are the medial clear space (normal less than 4mm, equal to the superior clear space within 1mm), the tibiofibular clear space (normal less than 6mm on the AP view), the tibiofibular overlap (greater than 6mm, or greater than 42 percent of fibular width), and the talocrural angle (83 plus or minus 4 degrees on the mortise view). Syndesmotic complex. Four components resist external rotation and lateral translation: the AITFL (from the Chaput tubercle to the Wagstaffe tubercle), the stronger PITFL (whose avulsion produces the Volkmann fragment), the distal interosseous tibiofibular ligament, and the interosseous membrane (disrupted extensively in a high Maisonneuve injury). The syndesmosis widens 1-2mm in dorsiflexion; disruption increases external rotation and lateral talar shift. Deltoid ligament. The superficial layer (tibiospring, tibionavicular, tibiocalcaneal, superficial tibiotalar) resists valgus; the deep layer (deep posterior tibiotalar, from the posterior colliculus) resists external rotation and lateral talar shift and is the most critical for mortise stability. A deep deltoid rupture allows lateral talar shift even with an intact superficial layer — the basis of the bimalleolar-equivalent injury. Fibular biomechanics. The fibula is a lateral buttress, maintains syndesmotic width, and bears 10-15 percent of the axial load. Length restoration is paramount — 2mm of shortening increases tibiotalar contact stress by about 42 percent — and rotation and sagittal alignment must both be restored. The blood supply comes from the peroneal artery (preserve the periosteal sleeve); the medial malleolus is supplied by branches of the posterior and anterior tibial arteries. Classification. The Weber system levels the fibular fracture against the syndesmosis and predicts stability; the Lauge-Hansen system describes the mechanism (foot position then deforming force) and the staged injury pattern, with supination-external rotation (SER) the most common mechanism at 40-75 percent.