Charnley low-friction arthroplasty of the hip. Long-term results.
Charnley low-friction arthroplasty (LFA) has become the method of choice for patients with destroyed arthritic hip joints; the authors' 18-26-year observation suggests that LFA could be considered the gold standard for total hip arthroplasty (THA). The continuity of concept, design, and the surgical technique extends beyond 29 years and offers predictability of outcome. Fatal postoperative pulmonary embolism, initially at 0.7% within one year of surgery, shows significant seasonal variation and as yet unexplained declining incidence. Incidence of dislocation is 0.63%, with a 0.11% chance of revision. The incidence of deep infection is 0.3%-1.5% in primary surgery and varies with the underlying hip pathology. Introduction of the intramedullary bone block has reduced the revision rate for stem loosening to less than 1% at 14 years and completely eliminated stem fracture. There has not been a fracture of a recently manufactured stem (Ortron). Revision for socket loosening has been reduced to 3% by the introduction of the ogee-flanged socket. The outcome of the socket survivorship is determined by the depth of socket penetration, the relationship between the two being exponential. Because the socket demarcation and migration are usually asymptomatic, the timing of revision would be determined by the surgeon's awareness of the problem. Repeated revisions produce conditions almost comparable to a locally malignant condition: dwindling bone stock, increasing implant size, local recurrence of the problem. Accumulation of the experience with the Charnley LFA has been shown to benefit both old and young patients.