Learning curve and short-term results with a short-stem CFP system.

In conservative hip replacement it is important to remove only pathological tissue to preserve as much healthy bone as possible. The collum femoris preserving (CFP) system preserves the femoral neck and metaphyseal cancellous bone. We present our learning curve with this system and our preliminary results and conclusions. During 2001-2009 we placed 138 CFP prostheses in 90 men and 38 women (10 bilateral). The mean age of the patients was 57.1 years (range 22-76 years) and the mean follow-up 38.3 months. Seventy-three patients were active workers at the time of surgery. All patients began partial weight bearing at 24-36 hours and total weight bearing was allowed at 3 weeks postoperative. We have had 1 infection, 2 intraoperative partial shaft fractures that did not require treatment, 1 acetabular loosening, and 2 periprosthetic traumatic fractures treated by osteosynthesis in one case and femoral revision in the other. All but 3 active workers returned to work and 54.5% of the studied patients practice some sport or physical activity. The stem size was correct in 125 hips. Resorption at the prosthetic rim was found in 9 out of 134 hips. No clinical symptoms were found in these patients. There have been no stem revisions for aseptic loosening in the follow-up study. Although the current follow-up is too short to allow definitive conclusions, the CFP system has provided excellent short-term results.