Resurfacing arthroplasty in osteonecrosis of the hip.

Approximately 10% of the total hip replacements performed in the United States are for osteonecrosis. Resurfacing arthroplasty has received renewed interest, with several new designs being implanted worldwide. Proponents of resurfacing arthroplasty describe the advantages of bone conservation, preservation of joint mechanics, more physiologic loading of the bone, lower incidence of perioperative complications, and easier conversion to a secondary procedure if failure occurs. Critics recite previous poor results including high failure rates with femoral and acetabular loosening, osteonecrosis of the femoral head, femoral neck fracture, and loss of acetabular bone stock making the secondary revision procedure more difficult. This article attempts to clarify the advantages and disadvantages of the resurfacing concept as it applies to the treatment of osteonecrosis of the femoral head.

Hip hemiarthroplasty after displaced femoral neck fracture: a survivorship analysis.

The standard of care for displaced femoral neck fractures is not clear. We reviewed all patients 65 years or older with displaced femoral neck fracture who underwent hip hemiarthroplasty at our institution between 1997 and 2006. Women accounted for 70% of the patients. Mean patient age was 78 years, and most of the patients were community ambulators. Complete operative information was available for 226 (79%) of 285 patients. Follow-up was available for 126 patients (mean, 15.8 months; range, 1-97 months). Total mortality rate was 58%. Mean University of California, Los Angeles (UCLA) scores were 8.3 for pain, 6.7 for walking, 5.6 for function, and 3.5 for activity. Two patients had acetabular wear on radiography, but symptoms were not severe enough to warrant revision. Three patients (1.3%) underwent revision, 1 with acetabular wear and 2 for infection. Despite the limited follow-up, the rate of conversion to total hip arthroplasty (THA) was low. Longer, prospective studies are needed to delineate which patients will benefit from THA.

Effect of changing indications and techniques on total hip resurfacing.

Recently, improved metal-on-metal bearing technology has led to the reemergence of resurfacing as a reasonable option for total hip arthroplasty. During the course of a prospective multicenter FDA-IDE evaluation of metal-on-metal total hip resurfacings, we modified our indications and emphasized surgical technique where the femoral surface area was small due to femoral cysts and small component size. We assessed the influence of these changes on complication rates in the first cohort of 292 patients and the second of 724, and then compared these outcomes in the second cohort with historical reports of resurfacing. We had a minimum followup of 24 months (mean, 33 months; range, 24-60 months). After changes were made in the indications and technique, the overall complication rate decreased from 13.4% to 2.1% with the femoral neck fracture rate reduced from 7.2% to 0.8%. The outcomes of the second cohort compare with modern-day resurfacing devices and appear superior to historical results. The data suggest patients should be carefully selected and technique optimized to reduce complications. Long-term followup is required to see if these promising results will be maintained.

Impact of implant design on femoral head hemiresurfacing arthroplasty.

Two consecutive series of cemented femoral hemiresurfacing arthroplasty for patients with Ficat Stage III and early Stage IV osteonecrosis of the femoral head were studied to identify the impact of design on the clinical and radiographic results. Group I (30 patients, 33 hips) components had a cobalt chrome shell with a tapered inner dimension, no stem, and sizes in 2-mm increments. Group II (37 patients, 51 hips) components differed by adding a proportional stem, increased spherical coverage, and sizes in 1-mm increments. The average age for the patients in both groups was 40 years. Fifty percent of the patients in Group I were men: in 43% of patients osteonecrosis was associated with steroid use and in 21% of patients it was associated with alcohol use. Thirty-three percent of the patients in Group II were men: in 41% of patients osteonecrosis was associated with steroid use and in 17% of patients it was associated with alcohol use. The average followup is 42 months for Group I and 24 months for Group II. Neither group experienced infections, nerve palsies, dislocations, or loosening. In Group I, two patients died of unrelated causes and five patients had reoperations, two for femoral neck fractures, and three for unsatisfactory pain relief. No patients in Group II had femoral neck fractures but three patients had reoperations for unsatisfactory pain relief. The stemmed component in Group II has resulted in an improvement in component position and elimination of femoral neck fractures in this series.