Diagnostic and prognostic value of clinical findings in 83 athletes with posterior thigh injury: comparison of clinical findings with magnetic resonance imaging documentation of hamstring muscle strain

BACKGROUND: Little is known about the clinical features of posterior thigh injuries and their contribution to accurate diagnosis and prognostic assessment of hamstring muscle strain injury. HYPOTHESES: The clinical features of posterior thigh injury can be used to diagnose hamstring muscle strain and to predict duration of absence from competition. STUDY DESIGN: Prospective clinical study. METHODS: For two playing seasons, the clinical features of posterior thigh injury, timing of injury, and playing days lost were recorded for Australian Rules football players. Magnetic resonance imaging was used to confirm hamstring muscle injury. RESULTS: Posterior thigh injuries associated with pain and tenderness were recorded for 83 players, with magnetic resonance imaging confirming hamstring injury in 68 (82%). Most of the hamstring injuries were sudden onset (62; 91%) and occurred after a significant warm-up period (57; 84%). Of the patients whose injuries were sudden onset and occurred after the warm-up period (N = 59), 57 (97%) had hamstring muscle strain detected on magnetic resonance imaging. Hamstring muscle injury confirmed by magnetic resonance imaging was associated with a longer absence from competition (mean, 27 days) than injuries where no hamstring injury was detected (mean, 16 days). CONCLUSIONS: The clinical features of hamstring injury typically include sudden onset, pain, and tenderness, although exceptions do occur. Muscle fatigue may be important in the pathogenesis of hamstring injury.