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

Abstract

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.

Midterm Results of Delta Ceramic-on-Ceramic Total Hip Arthroplasty

“…In addition, the THA patient population is becoming younger, more active, and more obese, and subsequently placing higher demands on the prosthesis and specifically the bearing surface [3]. Alternative bearings in THA have been developed in an attempt to reduce wear-related issues and improve implant longevity [4].…”

“…Recent bearing surface combinations include metal-on-polyethylene (MOP) and ceramic-on-polyethylene (COP) with cross-linked polyethylene [5], ceramic-on-ceramic (COC) [6,7], ceramic-on-metal (COM) [4] and metal-on-metal (MOM). Legitimate concerns with MOM bearing couples including ion production and adverse local tissue reactions have led to a drastic reduction in the usage of metal liners [8,9].…”

“…In addition, the THA patient population is becoming younger, more active, and more obese, and subsequently placing higher demands on the prosthesis and specifically the bearing surface [3]. Alternative bearings in THA have been developed in an attempt to reduce wear-related issues and improve implant longevity [4].Recent bearing surface combinations include metal-on-polyethylene (MOP) and ceramic-on-polyethylene (COP) with cross-linked polyethylene [5], ceramic-on-ceramic (COC) [6,7], ceramic-on-metal (COM) [4] and metal-on-metal (MOM). Legitimate concerns with MOM bearing couples including ion production and adverse local tissue reactions have led to a drastic reduction in the usage of metal liners [8,9].…”

Medium-term results of ceramic-on-polyethylene Zweymüller-Plus total hip arthroplasty

“…24 A previous comparison of four bearings revealed that ceramic-on-polyethylene bearing couple achieved the best results for revision for any reason (98.1%). 9 Similar to a previous description, the survival of the ceramic-on-polyethylene bearings in the Zweymüller-Plus system was relatively high in our study (99.0%).…”

Orthopedic implant approval: achieving the right balance

“…These articulations have been in use in orthopedics for over 50 years [1]. They enjoyed a resurgence over the past decade, promising greater longevity and higher activity levels.…”