Long-term (20- to 25-year) Results of an Uncemented Tapered Titanium Femoral Component and Factors Affecting Survivorship

Abstract

Background Uncemented femoral components in primary total hip arthroplasty (THA) are commonly used today, but few studies have evaluated their survival into the third decade. Questions/purposes We evaluated (1) survivorship using femoral revision for any reason as the end point; (2) survivorship using femoral revision for aseptic loosening as the end point; and (3) patient-related and surgical risk factors for aseptic stem loosening at a minimum 20-year followup with an uncemented tapered titanium stem.Methods We reviewed the clinical and radiographic results of 354 THAs in 326 patients performed between January 1985 and December 1989 using an uncemented grit-blasted, tapered titanium femoral stem. Mean age at surgery was 57 years (range, 13-81 years). Kaplan-Meier survivorship analysis was used to estimate long-term survival. Minimum followup evaluation was 20 years (mean, 22 years; range, 20-25 years); at that time, 120 patients (127 hips) had died, and four patients (five hips) were lost to followup. Multivariate survival analysis using a Cox regression model was performed. Results Survivorship at 22 years with revision of the femoral component for any reason as the end point was 86% (95% confidence interval [CI], 81%-90%). Survivorship for femoral revision for aseptic loosening as the end point was 93% at 22 years (95% CI, 90%-96%). Undersized stems (canal fill index B 80%) and stems in hips with cup revision were at higher risk for aseptic loosening (hazard ratio, 4.2 and 4.3, respectively). There was a high rate of acetabular revision in this series (38%), mostly related to smooth-threaded, cementless sockets. Conclusions Uncemented femoral fixation was reliable into the third decade. Age, male sex, and diagnosis were not associated with a higher risk of aseptic loosening.

Length of clinically proven cemented hip stems: State of the art or subject to improvement?

“…In other words, the more a stem reaches down underneath the level 80 mm below the lesser trochanter and, therefore, the more a distal movement expresses itself the less exactly the proximal stem bending can be defined. Nevertheless, stem bending ranges were within acceptable values that are comparable to the well-established CLS ® -stem (Zimmer Inc, Warsaw, IN, USA) [17,18,22]. Even though the CLS ® stem is made of a wrought Ti-6Al-7Nb alloy (Young's modulus≈ 110GPa) and therefore has elastic properties almost twice that of wrought high-nitrogen stainless steel, the cemented AMIS-K stem (X4-21Cr-9Ni-4Mn-Mo; Young's modulus≈190GPa) follows femoral bending in nearly the same way.…”

Early Migration Predicts Aseptic Loosening of Cementless Femoral Stems: A Long-term Study

“…The surgical procedures were performed by multiple surgeons at one institution. The operative technique and postoperative regimen with this implant have been described [32].…”

“…However, prediction of longterm implant performance is difficult and definitive results regarding aseptic loosening are available only after lengthy followup [24,32,33]. Widespread use of poor-performing implants might occur before these results are available [7,8].…”

Minimum ten-year results of a 28-mm metal-on-metal bearing in cementless total hip arthroplasty in patients fifty years of age and younger

“…Uncemented total hip arthroplasty in young and active patients has shown good to excellent long-term survivorship [15,16], but it still has to be considered challenging, especially with regard to longevity. MoM bearings were introduced to reduce PE wear and therefore provide long-term survival.…”