LONG-TERM SURVIVORSHIP OF THE MALLORY-HEAD CALCAR-REPLACING HIP PROSTHESIS - 4 TO 15 YEAR FOLLOW-UP

Abstract

Cementless femoral fixation is the gold standard in revision hip arthroplasty. Distal fixation is achieved using either a cobalt chrome or titanium stem. The purpose of this study is to report the long-term survivorship and clinical outcome of a titanium, long-stemmed, load-bearing calcar-replacement femoral component from an independent centre.

Eighty-one patients (average seventy-four years, range thirty-five to ninety-one) underwent hip arthroplasty with the Mallory-Head calcar-replacement femoral component, by a single surgeon. There were thirty-eight males and forty-three females with fifty-four hips initially revised for aseptic loosening, thirteen for peri-prosthetic fracture, and five for infection as a two-stage procedure. The implant was used as a primary device in eight patients with deformed proximal femurs. At most-recent follow-up, radiographic analysis was conducted and clinical outcome scoring was assessed using the SF-12, Harris Hip Score, and WOMAC questionnaire for surviving patients. Complications were also reviewed.

At a mean follow-up of 7.4 years (range four to fifteen), eight patients have died. There was one deep infection, three DVT’s, and two dislocations in the perioperative period. Six femoral stems have ultimately required another revision surgery for aseptic loosening, two for infection, and 1 for implant fracture at a mean of 5.6 years after initial revision. Four patients required removal of the proximal trochanteric bolt due to breakage or loosening. Overall survival of the implant at five years is 95% (CI 0.87–0.98) and 87% (CI 0.72–0.94) at ten years.

The clinical outcome of the Mallory-Head calcar-replacement femoral revision stem is reported from an independent centre. Although the results are encouraging, it would appear that proximal load-bearing fixation with the calcar-replacement stem is not as reliable as distal fixation. The use of a trochanteric bolt was associated with fracture of the greater trochanter or need for a separate surgical procedure for removal. For this series, there was an overall 11% failure rate at a mean follow-up of 7.4 years. The mechanical failure rate is 7.4%. Our overall and mechanical failure rates are somewhat higher than those of the implant developers, who reported 94% overall survival, and a 1.9% mechanical failure rate at a mean follow-up of eleven years.