Ring UPM total hip arthroplasty.

It is apparent that failure at the cement-bone interface is an increasing problem with total hip arthroplasty. This failure may be difficult or impossible to rectify. The risk of infection at the cement-bone interface and the difficulty of revisional surgery in the cemented articulation appear to justify fully an attempt to develop a reliable, uncemented total hip prosthesis. During the period from 1980 to 1982, 471 uncemented metal-on-plastic total hip arthroplasties have been performed. The results were compared with those for earlier metal-on-metal articulations and a comparable group of cemented metal-on-plastic joints. The short-term results for this procedure appear better than those obtained with the uncemented metal-on-metal articulation and comparable with those of the cemented joint, while retaining the relative freedom from complications of the uncemented articulation. The implant relies on the axial location of the pelvic component, and it is designed to be revised with ease, should revision prove necessary.