Clinical and radiological results of the collarless polished tapered stem at 15 years follow-up

Abstract

We prospectively followed 191 consecutive collarless polished tapered (CPT) femoral stems, implanted in 175 patients who had a mean age at operation of 64.5 years (21 to 85). At a mean follow-up of 15.9 years (14 to 17.5), 86 patients (95 hips) were still alive. The fate of all original stems is known. The 16-year survivorship with re-operation for any reason was 80.7% (95% confidence interval 72 to 89.4). There was no loss to follow-up, with clinical data available on all 95 hips and radiological assessment performed on 90 hips (95%). At latest follow-up, the mean Harris hip score was 78 (28 to 100) and the mean Oxford hip score was 36 (15 to 48). Stems subsided within the cement mantle, with a mean subsidence of 2.1 mm (0.4 to 19.2). Among the original cohort, only one stem (0.5%) has been revised due to aseptic loosening. In total seven stems were revised for any cause, of which four revisions were required for infection following revision of the acetabular component. A total of 21 patients (11%) required some sort of revision procedure; all except three of these resulted from failure of the acetabular component. Cemented acetabular components had a significantly lower revision burden (three hips, 2.7%) than Harris Galante uncemented components (17 hips, 21.8%) (p < 0.001).The CPT stem continues to provide excellent radiological and clinical outcomes at 15 years following implantation. Its results are consistent with other polished tapered stem designs.

Characterisation of the surface topography, tomography and chemistry of fretting corrosion product found on retrieved polished femoral stems

“…Similar figures have been presented for CoCrMo polished demonstrating revision rates of 4.1% 10 years postoperative (Burston et al, 2012). Although anecdotal at this time, a link between high revision rates due to ARMD and high levels of wear and corrosion of polished CoCrMo femoral stems when used with an all metal bearing seems to exist (Bolland et al, 2011;Donell et al, 2010).…”

“…However the exact tribo-chemical and tribological interactions taking place at these interfaces are not well investigated. Fretting-corrosion has been observed in a number of clinical cases on both polished and matte femoral stems (Burston et al, 2012;Fowler et al, 2011;Gie and Ling, 1994;Jasty et al, 1991). Howell et al (Howell et al, 2004) presented a comprehensive study, conducting SEM and 3-D interferometry analysis on both retrieved polished and matte femoral stems, identifying that polished and matte femoral stems present two very different wear mechanisms.…”

Galvanically enhanced fretting-crevice corrosion of cemented femoral stems

“…Polished tapered femoral stems generally have a good survivorship with revision rates of 2.8% at 7 years after operation being seen for commonly cemented stainless steel devices (Purbach et al, 2009). Similar figures have been presented for CoCrMo polished demonstrating revision rates of 4.1% 10 years postoperative (Burston et al, 2012). However recent studies have highlighted the importance of wear and corrosion, known as tribocorrosion, at the stem-cement interface with clinical studies implicating the interface with high failure rates due to ARMD (Bolland et al, 2011;Donell et al, 2010).…”

Survival outcomes of cemented compared to uncemented stems in primary total hip replacement

“…Advocates of cemented implants cite the excellent and reliable long-term reported survivorship [1][2][3] whereas proponents of cementless fixation contend that this method is equally reliable [4][5][6][7] and in fact superior in younger, highdemand patients [8,9] . Furthermore, cementless implants provide a broader range of options especially for the acetabulum where liner exchange may be required for postoperative instability; the commonest cause for early re-operation in all primary THR [10] .…”