Foot and Ankle
Core concepts
Understand lateral ankle sprains, syndesmotic injury, Achilles tendon rupture, plantar fasciitis, Lisfranc injury, Jones fractures, fifth metatarsal avulsions, stress fractures, posterior tibial tendon dysfunction, and osteochondral lesions of the talus. Know the Ottawa ankle rules, squeeze and external rotation tests, Thompson test, Windlass test, and midfoot stability examination. Distinguish acute lateral ligament injury from chronic instability. In athletes, stress fractures of the navicular, fifth metatarsal, and tibia require early recognition because displacement or nonunion changes return to play.
Traps
A Jones fracture is a metaphyseal-diaphyseal junction fracture with poor blood supply, not a proximal tuberosity avulsion. A normal nonweightbearing radiograph does not exclude Lisfranc injury; weightbearing views, CT, or MRI may be needed. A partial Achilles tear can still have a weak but present Thompson test. Plantar heel pain is not always fasciitis-consider calcaneal stress fracture, nerve entrapment, and fat pad atrophy. Do not treat every ankle sprain as benign if syndesmotic tenderness persists.
Worked example
A basketball player lands on a plantarflexed foot and has tenderness at the base of the fifth metatarsal. Rule of thumb: use the fifth metatarsal zones-zone 1 tuberosity avulsion, zone 2 Jones fracture, zone 3 proximal diaphyseal stress fracture. Zone 2 and displaced zone 3 fractures in athletes often warrant early surgical discussion because of nonunion risk.