Knee injury in patients experiencing a high-energy traumatic ipsilateral hip dislocation

BACKGROUND: Traumatic hip dislocation results from the dissipation of a large amount of energy about the hip joint. Clinically, these forces often are first transmitted through the knee en route to the hip. It is therefore logical to look for coexistent ipsilateral knee injury in patients with a traumatic hip dislocation. METHODS: Over a one-year period, we prospectively evaluated the ipsilateral knee of all patients who had a traumatic hip dislocation on the basis of a standardized history, physical examination, and magnetic resonance imaging. RESULTS: Twenty-one (75%) of the twenty-eight knees were painful. Twenty-five (89%) of the twenty-eight knees had visible evidence of soft-tissue injury on inspection. Magnetic resonance imaging revealed evidence of some abnormality in twenty-five (93%) of twenty-seven knees, with effusion (37%), bone bruise (33%), and meniscal tear (30%) being the most common findings. CONCLUSIONS: The present study provides evidence of a high rate of associated ipsilateral knee injuries in patients with a traumatic hip dislocation. Bone bruises may provide a plausible explanation for persistent knee pain following a traumatic hip dislocation. The liberal use of magnetic resonance imaging is recommended for the evaluation of these patients in order to detect injuries that may not be discoverable on the basis of a history and physical examination alone.