Long-term results of Charnley low-friction arthroplasty for coxarthrosis with congenital hip dysplasia. 15 year follow-up study
Nagano, H.; Inoue, H.; Usui, M.; Mitani, S.; Satoh, T.
Bulletin ) 56(4): 197-203
1997
ISSN/ISBN: 0018-5647 PMID: 9438078 Document Number: 473339
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 endpoint 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 endpoint 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 endpoint 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. In preoperative parameters, canal flare index, and Crowe's group were statistically significantly different between the loosening and non-loosening groups (p < 0.05). In immediate postoperative radiographic parameters, the horizontal distance of the location of the center of the femoral head and the adequacy of the cementing technique of stem were statistically significantly different between the loosening and non-loosening groups. The polyethylene average wear rate of the socket was 0.078 mm/year up to 10 years after surgery. The loosening group's average was 0.122 mm/year. The non-loosening group's average was 0.058 mm/year up to 10 years after surgery. The polyethylene wear rate up to 10 years after surgery was statistically significantly different between the loosening and non-loosening groups.