Dislocation after total hip arthroplasty.

Hip dislocation has long been one of the major complications after total hip arthroplasty (THA). From 1980 to 1994, we performed 2728 THAs (including primary and revision cases). There were 97 hips (3. 6%) with the complication of dislocation, 62 of which were followed up for at least 2 years (mean 5.3 years; range 2-12 years). Single dislocations occurred in 40% and recurrent dislocations in 60%. More than half of the dislocations (58%) occurred within 3 months after the index operation. The dislocation rate was not related to sex, age, previous revision surgery, or types of prosthesis, but was related to a smaller size of the femoral head. The rate of recurrent dislocation was not related to a history of previous surgery, but was related to a smaller femoral head, late onset of dislocation (> 3 months), soft-tissue imbalance, and cup malposition in both anteversion and inclination. If the size of the femoral head was 26 mm or smaller, a posterior approach was not recommended. Closed reduction followed by 1-2 weeks of skin traction was the treatment of choice. The success rate for the first attempt at closed reduction for the treatment of dislocation was 41%; the success rate decreased gradually with the number of attempts. For the recurrent dislocation group, bracing for 4-6 weeks with training was recommended for the postural type and bracing for 3 months with muscle training for the soft-tissue imbalance type. Only 15% of the dislocated hips needed re-operation, and most of the patients resolved the problem after being informed and undergoing muscle training.