A series of thirty-three Vitallium-mold arthoplasties performed for the residua of pyogenic and tuberculous hip infections has been evaluated and analyzed on the basis of a 100-point hip rating scale.

The indications for arthroplasty in this series of patients were to relieve pain, to improve motion, and to correct deformity. Rating each hip preoperatively by the rating scale was an aid in predicting the benefit to be gained from arthroplasty.

A postoperative flare-up of infection occurred after 21 per cent of the arthroplasties. A higher incidence of postoperative infection and an increased need for revision occurred in the hips with evidence of active infection at the time of surgery, but the average final result in these patients was not distinguishable from those of the other patients.

Revision of the arthroplasty was performed in four patients, three having had flare-ups of infection after the initial arthroplasty. The indications for revision were chronic drainage and loss of motion which was caused by either bone overgrowth or excessive soft-tissue scarring.

When all the patients were grouped accoring to their primary indication for arthroplasty, significant improvement occurred in each area. A successful result was dependent neither on the age of the patient nor on the duration of inactivity of the infection. A particularly rewarding degree of improvement from mold arthroplasty was observed in the unilateral pyogenic hips that had not progressed to ankylosis.