Extremities Limited Scope Practice Exam 2026 - Free Limited Scope Practice Questions and Study Guide

The midfoot’s stability depends on the tarsometatarsal joints that connect the forefoot to the midfoot, collectively known as the Lisfranc joint complex. When these joints are disrupted, often with tearing of the Lisfranc ligament between the medial cuneiform and the base of the second metatarsal, the forefoot can separate from the midfoot, leading to midfoot instability characteristic of a Lisfranc injury. The other injuries affect different areas: a fracture at the base of the fifth metatarsal involves the lateral column, a navicular fracture is a single midfoot bone injury that does not necessarily destabilize the tarsometatarsal joints, and a Chopart injury involves the hindfoot joints (talonavicular and calcaneocuboid). Thus, disruption of the tarsometatarsal joints produces the Lisfranc instability.