RESUMEN
The aim of the study was to validate a Finnish version of the internationally used Western Ontario and McMasters University osteoarthritis index (WOMAC) questionnaire, by testing its reliability, validity and responsiveness. The subjects of the study were patients scheduled for elective total knee arthroplasty (TKA) or total hip arthroplasty (THA). The patients completed the WOMAC questionnaire twice prior to surgery and once postoperatively to enable reliability, construct validity and responsiveness analysis. Test-retest reliability could be calculated for 67 patients (37 TKA and 30 THA). The intraclass correlation coefficients (ICC a) exceeded 0.9 with the exception of the stiffness subscale which averaged 0.8. Correlation of the preoperative WOMAC total score with the Harris Hip Score (HHS) in 30 patients and American Knee Society Score (AKSS) in 37 patients were mediocre ranging from 0.48 to 0.53. To test responsiveness, the first preoperative and the postoperative WOMAC scores of 74 subjects were compared (41 TKA and 33 THA). Standard response means (SRM) and effect sizes (ES) exceeded the recommended score of 0.8, ranging from 1.15 to 2.35. In conclusion the Finnish translation of the WOMAC questionnaire performs as the original, is valid and can be used in future studies of osteoarthritis.
Asunto(s)
Osteoartritis de la Cadera/diagnóstico , Osteoartritis de la Rodilla/diagnóstico , Índice de Severidad de la Enfermedad , Comparación Transcultural , Finlandia , Indicadores de Salud , Articulación de la Rodilla/fisiopatología , Osteoartritis de la Cadera/fisiopatología , Osteoartritis de la Rodilla/fisiopatología , Rango del Movimiento Articular , Reproducibilidad de los Resultados , Encuestas y CuestionariosRESUMEN
Ultra-high molecular weight polyethylene acetabular cups of 5 different total hip systems (Müller, Mallory-Head, Lubinus, P.C.A. and Charnley-Elite) were worn on a new 5-station hip joint simulator. The cups articulated against modular metallic (stainless steel in Müller and Charnley-Elite, ion-implanted Ti-6Al-4V in Mallory-Head, and Co-Cr-Mo in Lubinus and P.C.A.) and modular alumina ceramic femoral heads for 3 million walking cycles. The mean wear rate of cups against alumina heads (range 0-5.7 mg/10(6) cycles, corresponding to 0-0.008 mm/year) was usually lower than against metallic heads (range 3.9-178 mg/10(6) cycles, corresponding to 0.005-0.24 mm/year). In the metal-head prostheses, the mean wear rate was highest against stainless steel heads, and lowest against ion-implanted Ti-6Al-4V heads. As the wear rates are compared with published clinical observations, it can be concluded that the hip joint simulator is capable of producing realistic wear rates; it is a useful instrument in the study of the wear behavior of new designs, materials, surface treatments and coatings prior to clinical trials. However, the taper-fit attachment of modular heads proved problematical, showing corrosion and wear at the conical head-spigot interface.