Irreducible traumatic posterior hip dislocation with entrapment and a buttonhole effect.

The authors reported the case of a 27-year-old man who sustained an irreducible postero-lateral traumatic dislocation of the hip with capsular and labral entrapment. Initial X-rays showed only a small acetabular fragment. After two attempts to reduce the hip with muscle paralysis under general anaesthesia failed, the patient was treated by immediate open reduction through a postero-lateral approach. Surgical exploration of the hip revealed a small osteochondral fragment attached to a large piece of labrum and capsule, clogging the acetabulum. The femoral head crossed over the torn capsule with a buttonhole effect. These elements were relieved, the bone fragment was fixed with a 2 mm screw and the capsule was repaired. At the 10-year follow-up, the functional outcome was excellent with a Harris score of 100 points and no signs of necrosis or osteoarthritis. The authors propose a literature review of this uncommon lesion.