Wear rate of polyethylene in hybrid Total Hip Arthroplasty

Shon, Won Yong; Lee, Seok Hyun; Lim, Hong Chul; Rha, Kyong Wook; Kim, Hack Jun

Abstract

PURPOSE
Articles reporting on the wear rate of polyethylene cup in hybrid THA are rare. So, we now report the results of wear rate of polyethylene in cementless Harris-Galante acetabular components and cemented Harris precoat femoral stem.
MATERIALS AND METHODS
The cementless Harris-Galante acetabular components and cemented Harris precoat femoral stem of one-hundred hips in 71 patients were followed up for 2.5 ~ 7.5 years (mean 4.7 year) . The clinical results were evaluated by Harris hip score (HHS) and wear rates were measured using Livermore technique.
RESULTS
The most recent follow-up of HHS was improved from 52 to 91 in average. The mean linear wear rate in cemetless acetabular component was 0.17 0.06mm/yr (range 0.05 ~ 0.35) . Two femoral components were revised for aseptic loosening and one acetabular component revised for aseptic loosening. Wear rate in the revision group was higher than mean wear rate. In chronological change of wear rate according to final follow up period, there was decreasing tendency for mean wear rate with time. There was no correlation found between mean wear rate and body weight. There was a decreasing tendency on mean wear rate with acetabular cup shell size and increasing tendency with level of activity.
CONCLUSION
We concluded that cemented femoral stem was the reason for the trend in lower wear rate of polyethylene cup than which had been previously reported in cementless THA, but further follow-up studies will be needed to confirm that.