Musculoskeletal Injuries of the Lower Extremity
Hip and knee
Understand femoroacetabular impingement, labral tears, and hip flexor strains. In the knee, distinguish ACL (noncontact pivot, positive Lachman/pivot shift), PCL (dashboard injury, posterior sag), and meniscal tears (twisting with joint line tenderness, McMurray). Patellofemoral pain is common in adolescents and often managed with strengthening. Trap: an acute hemarthrosis after a contact injury suggests ACL or fracture; in skeletally immature patients, consider physeal injury.
Ankle and foot
Ankle sprains are usually lateral (inversion); the Ottawa ankle rules guide imaging. Achilles tendinopathy versus rupture (Thompson test). Plantar fasciitis causes first-step heel pain. Stress fractures are high-yield: tibial stress fracture (shin pain, focal tenderness), navicular and fifth metatarsal (Jones) fractures carry nonunion risk. Female athletes and those with low energy availability are at higher stress-fracture risk.
Rule of thumb
Apply the Ottawa ankle rules to decide imaging; a positive Thompson test means Achilles rupture and urgent referral. For any athlete with focal bone pain and a history of increased training load, consider stress fracture and modify activity before imaging confirms.