A long term study of Charnley total hip replacements.

Overview

This study concerns our first 100 Charnley low friction arthroplasties. The follow-up of the surviving forty hips ranged from 14.4 to 16.2 years (average 15.3 years). Thirty-nine of the original 100 hips were lost to follow-up due to death. Twenty-one could not be traced. There had been six known failures (defined as removal or revision of the prosthesis), two of which occurred in the surviving forty hips. Femoral component failure had occurred twice as often as acetabular failure. Survival analysis was performed using the last follow-up from all 100 hips. This depicted 91% survival of the arthroplasty (both components), 91% survival of the femoral component, and 96% survival of the acetabular component at fifteen years. Clinical evaluation of the surviving forty hips revealed 87.5% good and excellent results. This represented a small decline from 95% good and excellent results in the same hips at the ten year follow-up. Radiographic evaluation of thirty-two of forty hips demonstrated 6% migration of acetabular components, and 7% loose femoral components, while 31% of the acetabular components and 50% of the femoral components showed no sign of loosening. Femoral loosening was positively correlated with femoral shaft diameter. Measurable polyethylene wear was present in twenty-seven of thirty-two hips. The wear ranged from 0.2 to 8.5 millimeters (average 1.85 millimeters). Wear was associated with male sex and with calcar resorption.