Long-term Results of Charnley Low-friction Arthroplasty for Coxarthrosis with Congenital Hip Dysplasia. 15 Year Follow-up Study

We studied more than fifteen-years' follow-up results of cases treated with low-friction arthroplasty (LFA) for coxarthrosis with congenital hip dysplasia. Thirty-four LFAs in 32 patients (2 males and 30 females) were followed up for an average of 18.8 years (range: 15 to 23.3 years). The mean age at surgery was 53 years (range: 36 to 67 years). In three patients, 4 hips needed revision surgery due to loosening of the prostheses. At the final follow up, using Hodgkinson's criteria, type 0 demarcation of the socket appeared in 9 cases, type 1 in 5 cases, type 2 in 4 cases, type 3 in 4 cases, and type 4 in 12 cases. According to Harris' criteria, there was no sign of loosening of the stem in 16 cases, however there was a possibility of loosening in 8 cases, probability in 2 cases, and definite loosening in 8 cases. The survival rate with socket loosening as the end point was 76.5% at the 10 year follow-up, 67.6% at 15-years' follow-up, and 50.9% at 20-years' follow-up. The survival rate with stem loosening as the end point was 82.4% at 10-years' follow-up, 79.4% at 15-years' follow-up, and 63.8% at 20-years' follow-up. The survival rate with prostheses loosening either socket or stem as the end point was 64.7% at 10-years' follow-up, 55.9% at 15-years' follow-up, and 34.6% at 20-years' follow-up. The survival rate with revision surgery as the end point was 100% at 10-years' follow-up, 94% at 15-years' follow-up, and 85.1% at 20-years' follow-up.