Why a taper?

Abstract

The purpose of this study was to substantiate the continued use of a cementless plasma-sprayed, proximal-to-distal dual-tapered-geometry femoral-component design on the basis of long-term clinical and radiographic evidence. This justification is particularly pertinent in cementless total hip arthroplasty, in which bone-stock preservation and prosthetic-host compatibility are essential. A series of 101 patients managed with 120 primary arthroplasties who had a minimum follow-up of ten years was retrospectively reviewed. A meta-analysis of published reports of cementless tapered femoral components with a minimum follow-up of five years then was performed to validate the results of this review. At a mean follow-up of 12.2 years, a mean 38-point improvement in the Harris hip score was observed. Thigh pain was mild or absent after 97.5% (117) of the 120 arthroplasties. Distal femoral osteolysis was observed after 1.7% (two). Three femoral components had been revised secondary to aseptic loosening, yielding a 97.5% survivorship. Tapered geometries are an important feature in cementless femoral-component design, and the use of this design typically results in minimal thigh pain, a low incidence of stress shielding, and a low incidence of distal osteolysis. Designs with porous coating remain durable and continue to produce positive osseous responses, as observed radiographically. The Harris hip score improvement, the low incidence of severe thigh pain, and the high survivorship, coupled with a low incidence of substantial stress shielding and distal osteolysis, suggest excellent long-term results with the use of this specific cementless tapered design, adding credence to the design rationale and justifying its continued use. These data were supported by the results of an evidence-based meta-analysis, indicating similar results among cementless tapered designs. Although early reports of cementless total hip arthroplasties revealed low rates of aseptic loosening and stable bone ingrowth 1-5, other concerns regarding cementless fixation arose, including a higher …