The Charnley versus the Spectron hip prosthesis - Clinical evaluation of arandomized, prospective study of 2 different hip implants

Prospective, randomized studies must be performed when new surgical techniq ues or implants are evaluated. In this study, a new implant system was comp ared with the Charnley prosthesis, which over the years has been the most u sed hip implant in Sweden. Between 1985 and 1989, 410 hips were randomized to treatment with a Charnley or a Spectron total hip arthroplasty: 206 Char nley and 204 Spectron prostheses were implanted. The patients were operated on by a standardized procedure using a contemporary cementing technique. T he patients were followed prospectively by an independent observer after 1, 3, 5 to 6, and 10 years. Harris Hip Score and patient satisfaction were re corded in the outcome evaluation. A total of 144 patients with 164 hips wer e deceased, and 15 patients (8 Charnley and 7 Spectron) have required a rev ision. Nine hips were revised because of aseptic loosening (5 Charnley stem s and 4 Spectron metal-backed cups). The Charnley stem as well as the metal -backed Spectron cup had a higher risk for revision because of aseptic loos ening. The Charnley ogee cup and the Spectron stem have performed remarkabl y well with no revision of these components. Seven Charnley prostheses disl ocated, but no dislocation was recorded in the Spectron group. Survivorship calculations with a mean follow-up of 10 years revealed an overall Ii-year survivorship of 94.5% +/- 3.4% (Charnley, 93.2% +/- 5.8%; Spectron, 95.9% +/- 3.0%). The clinical outcome did not differ between the 2 systems. The o verall results in this old population, using a contemporary surgical techni que, illustrate that cemented hip arthroplasty is an excellent treatment al ternative for elderly patients.