Intramedullary cancellous bone block to improve femoral stem fixation in Charnley low-friction arthroplasty.

In order to improve the fixation of the stem in primary Charnley low-friction arthroplasty, the medullary canal was routinely closed off with a cancellous bone block. A prospective study of 611 consecutive arthroplasties were carried out between 1 and 5 1/2 years (average 2 years and 9 months) after operation. There were two cases of radiological loosening of the stem, both of which could have been avoided. Five other patients showed demarcation of the bone-cement junction at the calcar; two of these are considered to be "at risk" of loosening. There was no evidence of radiological loosening of the stem in 604 cases and the method is recommended for routine use in primary total hip arthroplasty.