How outcome studies have changed total hip arthroplasty practices in Sweden.

The Swedish Hip Registry has defined the epidemiology of total hip replacement in Sweden. Most hip implants are fully cemented. Serious complications and rates of revision associated with total hip replacement have declined significantly despite an increasing number of patients at risk. During the past 5 years only 9% to 10% of hip replacement procedures are revision procedures. Aseptic loosening with or without osteolysis is the major problem and constitutes 73% of the revisions, but the incidence has decreased four times during the past 15 years to less than 3% at 10 years. Even septic complications can be prevented effectively. Demographics are important because male gender and young age increase the risk for revision because of aseptic loosening. Young female patients with rheumatoid arthritis and male patients with a previous hip fracture have five times higher revision rates than elderly patients. The quality of the surgical technique is the most important factor for reducing the risk for revision because of aseptic loosening, but choice of implant is also important. The variations among hospitals in type of surgical technique used is big enough to cause a 100% difference in revision rate for aseptic loosening. Total hip replacement practice in Sweden has improved based on information from this Registry about individualized patient risks, implant safety, and the efficacy of improving surgical and cementing techniques.