Foot and Ankle Surgery
What this domain tests
Ankle fracture classification and syndesmotic injury, Achilles tendon management, adult flatfoot, hallux valgus, Lisfranc injury, and the diabetic foot.
Core rules
- Ankle fractures: Danis-Weber depends on the level of the fibular fracture relative to the syndesmosis; Lauge-Hansen describes the injury mechanism. Restore the mortise, the fibular length, and the syndesmosis. Posterior malleolar fragments above roughly 25-30% of the articular surface should be fixed.
- Achilles tendon rupture: functional bracing and surgical repair give similar re-rupture rates in compliant patients; surgery reduces re-rupture but adds wound risk, especially in diabetics and smokers.
- Posterior tibial tendon dysfunction is staged clinically: flexible flatfoot with a single-heel raise failure requires tendon transfer and calcaneal osteotomy; rigid deformity requires arthrodesis.
- Hallux valgus: assess the intermetatarsal angle, hallux valgus angle, and tarsometatarsal stability; distal osteotomy for mild deformity, first tarsometatarsal fusion for hypermobility.
- Lisfranc injuries need weight-bearing imaging or CT; the diastasis between the medial cuneiform and second metatarsal base is the key measure.
Worked example
A 45-year-old falls from a step with midfoot pain. Non-weight-bearing radiographs are normal, but there is tenderness at the first and second tarsometatarsal joints and a 2 mm widening on stress views. Answer: presumed Lisfranc injury, confirm with weight-bearing CT, then anatomic reduction and screw fixation for a purely ligamentous injury, or primary arthrodesis for a bony-ligamentous pattern in a young active patient.
Traps that cost marks
- Accepting non-weight-bearing films as normal in a suspected Lisfranc injury.
- Missing syndesmotic injury when the mortise looks acceptable on a static film.
- Operating early on a Charcot foot before the acute phase resolves.