Implant survival after a total hip or knee replacement in Catalonia up to five years of follow-up: a population-based register (RACat)

Abstract

s / Osteoarthritis and Cartilage 20 (2012) S54–S296 S180 Function and disability were assessed with the WOMAC and LLFDI instruments respectively. Severity of knee pain was assessed on a 0-100 numeric rating scale and subjects provided information on depressive features (CES-D), educational level, race, co-morbid conditions (Charlson) and use of pain medications. The presence of widespread pain was determined. Subjects who reported a knee steroid injection in the past year or were missing x-ray, knee pain, function or disability data were excluded. Pain analyses were knee-based, stratified by KL grade and used generalized estimating equations to control for covariance between knees. Physical function and disability analyses were person-based and utilized general linear models. For person-based analyses, subjects were grouped by the combination of maximum KL grade and the contralateral knee KL grade. Some groups were combined to increase the number of subjects per level as follows: KL grade <2/<2, 2/<2, 2/2, 3/<2, 3/2, 3/3 and 4/0-4. Analyses evaluated whether there were significant sex differences in each group of knees before and after adjustment for age, BMI, co-morbidity, CES-D, clinic site, educational level, frequent use of pain medications, race, and widespread pain. Results: A total of 2731 subjects (5462 knees) were included in the analyses. Men and women did not significantly differ in age (62.0 8.3 vs. 62.3 7.9 years), BMI (30.4 5.1 vs. 30.6 6.3 kg/m2) or comorbid conditions (p1⁄40.3734). More women than men had CES-D scores above a depression screening cutoff (13.5% vs. 7.8%, p<0.0001), widespread pain (56.2% vs. 40.5%, p<0.0001) and bilateral knee OA (27.3% vs. 21.2%, p1⁄40.0003). A greater percentage of men than women reported frequent salicylate analgesic use (46.2% vs. 34.4%) while a greater percentage of women used NSAIDs on a frequent basis (26.9% vs. 19.6%, all p<0.0001). Women reported significantly greater knee pain severity compared with men in all KL grades (<2:p<0.0001, 2:p1⁄40.0034, 3:p1⁄40.0002 and 4:p1⁄40.0106) in unadjusted analyses and in KL grades <4 (<2:p1⁄40.0020, 2:p1⁄40.0298, 3:p1⁄40.0318 and 4:p1⁄40.1128) in adjusted analyses. In unadjusted analyses, lower function and greater disability were found in women compared withmen at KL grade<2/<2 (p<0.0001). There were no sex differences in the KL grade group with an osteophyte in the index but not contralateral knee (2/<2), while in those with osteophyte in both knees (2/2) women had lower function (p1⁄40.0380) but not more disability than men. With unilateral (3/<2) and bilateral (3/3) joint space narrowing, women had lower function (p1⁄40.0004 and p1⁄40.0009) and greater disability (p1⁄40.0189 and p1⁄40.0270) compared with men that remained significant in adjusted analyses (Table). No significant differences were found in KL grade group 3/2. Finally, in KL grade group 4/0-4, women had greater disability (p1⁄40.0009), that remained significant after adjustment, but not lower function compared with men. Adjusted Mean Function and Disability Scores in Women Compared with Men (LSmeans±SE) KL Grade Group Sex Function