Health Services/Policy
Relationship between surgical appropriateness, contextual factors, and pain trajectories following total knee replacement for knee osteoarthritis: A group-based trajectory modeling analysis Tristan Watson* Tristan Watson Arjumand Siddiqi Laura Rosella Peter Smith Gillian Hawker
Background: Total knee replacement (TKR) is a common intervention for individuals with knee osteoarthritis (OA) seeking pain relief and improved function. However, 20% of TKR recipients report minimal pain improvement, highlighting the need to identify the determinants of a good pain outcome following TKR. This study examines post-TKR pain trajectories and their preoperative determinants, including surgical appropriateness, surgical complication risk, and contextual factors.
Methods: We used data from the Best Evidence for Surgical Treatment study, a prospective longitudinal study of patients who underwent TKR in Alberta, Canada. Pain was assessed using the Western Ontario and McMaster Universities Arthritis Index. Surgical appropriateness was evaluated based on measures of TKR need (e.g., knee pain and disability), readiness/willingness, and patient expectations. Group-based trajectory modeling was used to examine pain trajectories over one year. Multinomial logistic regression explored the association between the baseline determinants and pain trajectory membership.
Results: Among 1374 TKR recipients, we identified three pain trajectories: “good outcome fast” [n = 158], “good outcome slow” [n = 1071], and “poor outcome” [n = 145]. Individuals in the poor outcome trajectory group had greater TKR need, but lower readiness/willingness for surgery and more unrealistic surgical expectations. Controlling for these factors, they were also more likely to have a postoperative complication, be male, have higher education, and have low back pain. The final model had moderate discrimination of the poor outcome but poor discrimination across all three pain trajectories.
Conclusions: We identified three distinct pain trajectories following TKR for knee OA. Surgical appropriateness and contextual factors were both associated with postoperative pain outcomes. Incorporating these factors may enhance patient outcomes and support TKR decision-making.