Alternative bearing surfaces in total hip arthroplasty

Implants for total hip arthroplasty

This article is a comprehensive review of the published literature on total hip replacement design. It seeks to provide a nonbiased view of the technology related to total hip implants and bearing surfaces. Implant designs and fixation methods are discussed with summaries of their respective long-term outcome studies. Fixation methods include cemented, cementless and hybrid techniques and are explained and presented with current outcome data and their respective failure modes that have promoted new technological development. The current data point toward cementless acetabular fixation as being superior to cemented fixation. As for stem fixation, there are good data to suggest that either method of fixation is acceptable in the proper setting. Also included in this article is a brief review of bearing surfaces and hip biomechanics.

State of the art in hard-on-hard bearings: how did we get here and what have we achieved?

Total hip arthroplasty has shown excellent results in decreasing pain and improving function in patients with degenerative disease of the hip. Improvements in prosthetic materials, designs and implant fixation have now resulted in wear of the bearing surface being the limitation of this technology, and a number of hard-on-hard couples have been introduced to address this concern. The purpose of this article is to review the origins, development, survival rates and potential advantages and disadvantages of the following hard-on-hard bearings for total hip arthroplasty: metal-on-metal standard total hip arthroplasty; metal-on-metal hip resurfacing arthroplasty, ceramic-on-ceramic total hip arthroplasty; and ceramic-on-metal bearings. Improvements in the manufacturing of metal-on-metal bearings over the past 50 years have resulted in implants that provide low wear rates and allow for the use of large femoral heads. However, concerns remain regarding elevated serum metal ion levels, potential teratogenic effects and potentially devastating adverse local tissue reactions, whose incidence and pathogenesis remains unclear. Modern total hip resurfacing has shown excellent outcomes over 10 years in the hands of experienced surgeons. Current ceramic-on-ceramic bearings have demonstrated excellent survival with exceptionally low wear rates and virtually no local adverse effects. Concerns remain for insertional chipping, in vivo fracture and the variable incidence of squeaking. Contemporary ceramic-on-metal interfaces are in the early stages of clinical use, with little data reported to date. Hard-on-hard bearings for total hip arthroplasty have improved dramatically over the past 50 years. As bearing designs continue to improve with new and modified materials and improved manufacturing techniques, it is likely that the use of hard-on-hard bearings will continue to increase, especially in young and active patients.

Natural history of squeaking after total hip arthroplasty

BACKGROUND

In recent years, a number of alternative bearing surfaces, such as ceramic on ceramic, are being used in THA. Squeaking after THA is a recently recognized complication; however, its incidence is unknown.

QUESTIONS/PURPOSES

Find the incidence of squeaking; when it ensues; activities associated to squeaking; its natural history, and outcome of revisions for squeaking.

METHODS

A prospective observational study between 2002 and 2007; yield 1486 ceramic-on-ceramic THA performed at our institution. All patients were followed up by office visits or by phone, to obtain information regarding squeaking, pain and function. Minimum followup was 2.5 years (mean, 5.5 years; range, 2.5-7.9 years).

RESULTS

Ninety-five of the 1486 hips (6%) developed squeaking after THA, 39 females (44%) and 49 males (56%) with an average age of 49.9 years. Squeaking began on average 19.7 months after surgery but not associated with pain or functional impairment in any patient. Squeaking could be heard during walking (38%), ascending stairs (24%), bending forward (21%), and other activities (18%), was constant in 26% of the patients and intermittent in 74%. The intensity and frequency remained similar over time in 70% of the patients.

CONCLUSIONS

Squeaking is a real phenomenon that occurred in about 6% of our patients. The etiology for this problem remains elusive and is likely to be multifactorial in nature. Squeaking, when developed, does not seem to be self-limited and persists in the majority. Nine patients underwent revision arthroplasty for squeaking. No fractures or other implant-related issues were observed.

LEVEL OF EVIDENCE

Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Two- to 9-year clinical results of alumina ceramic-on-ceramic THA

From June 1997 to June 2003 we performed 194 total hip arthroplasties on 173 patients using alumina ceramic-on-ceramic bearings as part of a prospective United States Food and Drug Administration/Investigational Device Exemption study. The average patient age at surgery was 49.9 years. Minimum followup time was 2 years (mean 4.3 years, range 2-9 years). We evaluated survival rate, implant- and nonimplant-related complications. Clinical outcomes included the Merle d'Aubigné score. We assessed radiographs for signs of osteolysis, component loosening, and implant wear. No patients had osteolysis and there were no hip dislocations. Implant survivorship for all hips with aseptic revision of any component was 96% (CI, 91-100) at 9 year; survivorship for hips without prior surgery was 99.3%, (CI, 98-100). There was a 1.7% incidence of implant-related complications. Our data help confirm two United States FDA/IDE studies on alumina ceramic-on-ceramic total hip arthroplasty that reported low aseptic revision rates and low revision rates for instability. Total hip arthroplasty using alumina ceramic-on-ceramic implants is a safe and reliable procedure in the comparably young and active patient.