Ten-year results of a double-heat-treated metal-on-metal hip resurfacing

Abstract

Second-generation metal-on-metal bearings were introduced as a response to the considerable incidence of wear-induced failures associated with conventional replacements, especially in young patients. We present the results at ten years of a consecutive series of patients treated using a metal-on-metal hip resurfacing. A distinct feature of the bearings used in our series was that they had been subjected to double-heat treatments during the post-casting phase of their manufacture. In the past these bearings had not been subjected to thermal treatments, making this a unique metal-on-metal bearing which had not been used before in clinical practice. We report the outcome of 184 consecutive hips (160 patients) treated using a hybrid-fixed metal-on-metal hip resurfacing during 1996. Patients were invited for a clinicoradiological follow-up at a minimum of ten years. The Oxford hip score and anteroposterior and lateral radiographs were obtained. The mean age at operation was 54 years (21 to 75). A series of 107 consecutive hips (99 patients) who received the same prosthesis, but subjected to a single thermal treatment after being cast, between March 1994 and December 1995, were used as a control group for comparison. In the 1994 to 1995 group seven patients (seven hips) died from unrelated causes and there were four revisions (4%) for osteolysis and aseptic loosening. In the 1996 group nine patients died at a mean of 6.9 years after operation because of unrelated causes. There were 30 revisions (16%) at a mean of 7.3 years (1.2 to 10.9), one for infection at 1.2 years and 29 for osteolysis and aseptic loosening. Furthermore, in the latter group there were radiological signs of failure in 27 (24%) of the 111 surviving hips. The magnitude of the problem of osteolysis and aseptic loosening in the 1996 cohort did not become obvious until five years after the operation. Our results indicate that double-heat treatments of metal-on-metal bearings can lead to an increased incidence of wear-induced osteolysis.

Socket Position Determines Hip Resurfacing 10-Year Survivorship

“…Ten-year clinical and survivorship results of metal-onmetal hip resurfacing have been reported [6,14,16,39] but are still not available from a majority of centers performing this type of surgery. Also, of the three reports with 10-year data, only two used currently available devices [6,39].…”

Indications and results of hip resurfacing

“…The extremely low incidence of component loosening in our series shows that fixation problems have largely been solved in the BHR in contrast to the loosening reported [18] with the Durom resurfacing device (Zimmer, Swindon, UK). In addition to failures due to reasons such as infection, resurfacings fail through one of two modes, mechanical failures such as femoral neck fractures and bearing-related failures such as failures due to osteolysis [19], soft tissue reactions and periarticular necrosis [20]. These can occur due to one of three risk factors: patient-related, surgeon-related and implant-related.…”

“…The many nuances [32] of implant design and materials constitute the third risk factor for resurfacing failures. Our past experience [19] has shown that changes to materials processing can be detrimental to implant survivorship. More recently the consistently poor performance of the ASR device (Johnson & Johnson DePuy Ltd., Leeds, UK) was shown to be due to unfavourable design features such as the low angle of articulation and reduced diametral clearance [16].…”

Risk of Impingement and Third-body Abrasion With 28-mm Metal-on-metal Bearings

“…Both positive [2,11] and negative reports [25,34,35,37,61] have emerged with regard to using MoM bearings. There are likely many risks that could trigger a need for MoM revision.…”