Musculoskeletal Medicine and Sports Injuries
Knee
Anterior cruciate ligament rupture is suggested by a noncontact pivoting mechanism, an audible pop, hemarthrosis developing within hours, and a positive Lachman test, which is the most sensitive maneuver, particularly in the acute swollen knee where the anterior drawer is harder to interpret. The pivot shift is the most specific. Meniscal tears cause joint-line tenderness and mechanical symptoms; McMurray is specific but insensitive, so a negative test does not exclude a tear. A locked knee from a displaced bucket-handle tear needs urgent referral.
Shoulder
Glenohumeral instability in a young contact athlete carries high recurrence risk; apprehension and relocation testing plus load-and-shift are the workhorses. Overhead throwing pain is more often internal or posterosuperior impingement than classic subacromial impingement, so Neer and Hawkins tests are nonspecific. Test subscapularis with the belly-press and lift-off signs, and the biceps with Speed and Yergason tests.
Hip
Femoroacetabular impingement produces anterior groin pain, restricted flexion with internal rotation, and a positive FADIR. FABER localizes to the hip or sacroiliac joint but is less specific. Labral tears often cause C-sign pain.
Spine and extremity
Extension-provoked low back pain in an adolescent suggests spondylolysis; oblique radiographs have poor sensitivity, so MRI or limited CT is preferred. Ankle sprains are imaged according to the Ottawa ankle rules (bone tenderness at the posterior malleolus or navicular, or inability to bear weight four steps). Achilles and patellar tendinopathy respond to progressive eccentric loading.
Rule of thumb: in an acute hemarthrosis after a twisting injury, assume ACL until proven otherwise and splint, ice, and refer rather than repeatedly re-examining a tense knee.
Traps
- Confusing spondylolysis with spondylolisthesis on imaging.
- Treating a locked knee as a sprain.
- Overreliance on MRI before a competent exam.