Pain during walking and stair climbing was more closely associated with 1-year satisfaction than functional limitations among patients who underwent total hip or total knee arthroplasty, according to a registry-based cohort study.

Researchers analyzed data from the Geneva Arthroplasty Registry, which captured 3,278 primary total hip arthroplasties and 2,478 primary total knee arthroplasties performed from January 2012 to June 2022 at a tertiary care university hospital. After exclusions, the analytic cohort included 1,772 total hip arthroplasties and 1,323 total knee arthroplasties with complete 1-year Western Ontario and McMaster Universities Osteoarthritis Index pain and function data and patient satisfaction responses.

Patient satisfaction was assessed 1 year following surgery using a 5-point Likert scale, and Western Ontario and McMaster Universities Osteoarthritis Index summary scores were reported on a 0-to-100 scale, with higher scores indicating better outcomes. All analyses were performed separately for the two populations. Patients who underwent total hip arthroplasty reported higher satisfaction than those who underwent total knee arthroplasty, with 93% vs 82% reporting that they were satisfied or very satisfied. The two groups also differed at baseline, with total hip arthroplasty patients being younger and having lower body mass index and fewer comorbidities.

In ordinal logistic regression models, better postoperative pain and function scores were each associated with higher satisfaction in both arthroplasty groups when examined individually. When pain and function were analyzed together in mutually adjusted models, pain showed the stronger association, although function remained statistically significant. Each 1-standard-deviation improvement in pain score was associated with 2.8 times the odds of higher satisfaction following total hip arthroplasty and 3.6 times the odds following total knee arthroplasty. By comparison, each 1-standard-deviation improvement in function score was associated with 1.3 and 1.2 times the odds, respectively.

The researchers reported that postoperative scores were more closely related to satisfaction than changes from baseline, which supported their focus on 1-year postoperative outcomes. Because pain, function, and satisfaction were assessed at the same 1-year follow-up, the findings should be interpreted as same-timepoint associations rather than evidence that postoperative pain or function predicted later satisfaction.

At the item level, less pain while walking on flat ground and while going up or down stairs had the strongest associations with satisfaction in both the total hip and total knee arthroplasty groups. The researchers described these activity-specific analyses as exploratory, with no adjustment for multiple comparisons.

Function-related associations varied by procedure. Among patients who underwent total hip arthroplasty, walking on flat ground, putting on socks, and ascending stairs were the functional activities most strongly associated with satisfaction. Among patients who underwent total knee arthroplasty, walking on flat ground, sitting, rising from sitting, and getting in or out of a car showed the strongest functional associations, although the researchers emphasized walking, rising from sitting, and getting in or out of a car in their summary of key contributors.

The researchers suggested that these differences may reflect the distinct biomechanical demands placed on the hip vs the knee. They noted that difficulty putting on socks affected satisfaction only among total hip arthroplasty patients, whereas difficulty getting in or out of a car affected satisfaction only among total knee arthroplasty patients.

The researchers noted several limitations. Outcomes were evaluated only at 1 year, so the findings cannot be generalized to later follow-up points. Various methods exist for measuring patient satisfaction, which may affect results, although the researchers stated that their approach followed International Society of Arthroplasty Registries recommendations. In addition, 705 eligible total hip arthroplasties and 593 eligible total knee arthroplasties were excluded from the final analysis, most often because of missing or incomplete 1-year Western Ontario and McMaster Universities Osteoarthritis Index data. The researchers acknowledged that missing data that are not missing completely at random could introduce bias, while noting that complete outcomes were available for 74% of total hip arthroplasties and 72% of total knee arthroplasties, exceeding the threshold they considered sufficient to support a complete-case approach.

The findings suggest that pain during common daily activities, particularly walking on flat ground and going up or down stairs, was more strongly associated with patient satisfaction following total hip and total knee arthroplasty than limitations in functional abilities.

“Patient satisfaction was more strongly influenced by postoperative pain than by limitations in functional abilities after surgery,” wrote lead study author Marys Revaz, of Geneva University Hospitals and the University of Geneva, and colleagues.

Disclosures: Institutional support for the Geneva Arthroplasty Registry was provided by the Fondation pour la recherche ostéoarticulaire. The researchers reported no conflicts of interest.

Source: Acta Orthopaedica