IDIOPATHIC HIP INSTABILITY - AN UNRECOGNIZED CAUSE OF COXA SALTANS INTHE ADULT

The painful, snapping hip often presents a diagnostic dilemma having m any potential etiologies, An understanding of the precise cause increa ses the potential for successful treatment. Five patients with no prio r history of significant trauma were evaluated, all of whom had longst anding painful snapping in the groin and consistent symptoms of gait d isturbance and increased pain in the provocative position of hip flexi on, adduction, and internal rotation. Multiple prior tests and procedu res had been nondiagnostic. Simple manual longitudinal traction under fluoroscopy showed subluxation with appearance of a vacuum sign in the symptomatic hip, whereas no such finding was observed on the asymptom atic side. This strongly suggests atraumatic hip instability as a prev iously unrecognized cause of the painful, snapping hip. The easily obt ainable diagnostic traction radiograph is described.