Hip resurfacing results for osteonecrosis are as good as for other etiologies at 2 to 12 years

Abstract

A bone-conserving prosthetic solution, such as hip resurfacing arthroplasty, is desirable for patients with osteonecrosis (ON) of the femoral head because of their young age. However, many surgeons are reluctant to perform hip resurfacing for ON because of large femoral head defects. To ascertain whether this reluctance is warranted, we determined the mid- to long-term effects of ON on the survivorship, radiographic implant fixation, and disease-specific and quality-of-life scores of hip resurfacing. We compared the results of metal-on-metal resurfacing performed for ON of the hip (including large lesions) with those of resurfacing performed for other causes. The ON group had 70 patients (85 hips) and the control group 768 patients (915 hips) including all other etiologies operated on during the same period. The ON group was younger and had a greater incidence of femoral defects, a smaller component size, and a lower body mass index, three variables previously shown to reduce survivorship in hip resurfacing. We observed no difference in survivorship between the ON group and the control group even after adjusting for head size, body mass index, and defect size. Pain relief, walking, and function scores were comparable postoperatively. The activity level was lower in the ON group. Our data suggest ON is not a contraindication for resurfacing even with large femoral head defects.

Level of evidence: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Fig. 1A–B

(A) Anteroposterior radiograph of a 52-year-old man with bilateral steroid-induced Ficat Stage IV osteonecrosis. The insets show the extent of the femoral defects after removal of the necrotic lesions. In this case, the length of the neck could not be maintained because the femoral defects were too large to preserve a part of the chamfered area. (B) Eight years after resurfacing, the components are securely fixed and the patient’s UCLA hip scores are 10, 10, 10, and 7 for pain, walking, function, and activity, respectively.

Fig. 2A–D

(A) Anteroposterior radiograph of a 49-year-old woman with bilateral alcohol-induced osteonecrosis of the hips, Ficat Stage IV. The insets show the femoral heads after preparation for resurfacing. (B) The patient underwent two-stage bilateral resurfacing and is shown 6 months after her right-sided operation (the component was placed in relative varus with the metaphyseal stem left uncemented) and 3 months after the left. (C) Five years after surgery, the femoral component loosened on the right side and tipped into further varus. (D) Conversion to THA; the well-fixed acetabular component was left in situ and the femoral component replaced with an ATH long stem grit-blasted and a 40-mm unipolar head.

Fig. 3

Comparative Kaplan-Meier survivorship curves of the osteonecrosis group and the rest of the cohort. The time to revision for any reason was used as the end point. The two groups of patients had similar survivorship.