Results of uncemented porous-coated anatomic total hip replacement

Abstract

We reviewed a consecutive series of 241 uncemented, porous-coated anatomic (PCA) hip replacements at an average follow-up of five years (2 to 9). Of these, 32 had failed (13%), 26 at the acetabular component (11%) and six at the femoral component (2%). Acetabular failure was associated with local osteolysis and excessive polyethylene wear in 20 cases: in these histological examination showed giant macrophages incorporating numerous particles of high-density polyethylene. The femoral failures were related to a poor intramedullary fit with subsequent subsidence. Using the recommendation for revision as the end point, the cumulative survival rate for prostheses was 91% at six years (95% CI +/- 6%), 73% (+/- 11%) at seven years, and 57% (+/- 20%) at eight years. The result of uncemented PCA hip replacement is satisfactory up to six years, but then increasing failure of the acetabular component appears to be due to polyethylene wear, leading to osteolysis, loosening and component migration. At first, failure is often asymptomatic; routine follow-up of uncemented hip replacement is essential, especially after five years.

Polyethylene wear with an entirely HA-coated total hip replacement 79 hips followed for 5 years

“…Only some of our hips contributed to the high annual wear rate. Owen et al (1994) noted severe wear of the polyethylene liner in 14% of 226 PCA hips, and Kim and Kim (1993) found excessive polyethylene wear in 17% of 116 PCA hips, mean 7.4 (5-11) mm. The average wear rate in these cases was 1.3 mm per year.…”

Poor survival of cementless Biomet® total hip: A report on 1,047 hips from the Finnish Arthroplasty Register

“…Nevertheless, the use of cementless components has steadily increased. In many studies (Bono et al 1994, Owen et al 1994, Hozack et al 1996, Barrack et al 1997, the poor performance of press-fit cups has been the success-limiting factor of the procedure. In several studies, the survival of the acetabular and femoral components are treated separately.…”

Migration of Cemented Femoral Components After THR

“…Early clinical assessment of the performance of a new design of total hip replacement is notoriously unreliable: full evaluation of function requires a clinical trial of at least ten years (Murray, Carr and Bulstrode 1993;Owen et al 1994). By then, if the implant is unsatisfactory, many patients will have suffered.…”