Background
Total knee replacement (TKR) is an effective treatment to relieve pain and restore function in patients with advanced knee osteoarthritis (OA). TKR utilization is growing rapidly, and the appropriateness of current TKR use is of great interest. We examined patient-reported pre-operative pain and function profiles to understand symptom severity at the time of TKR decision.
Methods
Data were from FORCE-TJR. We included patients undergoing primary, unilateral TKRs between 2011 and 2014 for OA, and had data on the Knee Injury and Osteoarthritis Outcome Score (KOOS) pain and SF-36 Physical Component Summary (PCS) score. We compared patient profiles across groupings by symptoms: 1) little pain-and-high function (KOOS≥70, PCS≥40), 2) little pain-but-poor function (KOOS≥70, PCS<40), 3) high pain-but-high function KOOS<70, PCS≥40), and 4) high pain-and-poor function (KOOS<70, PCS<40).
Results
Of 6,936 patients, 77% had high pain-and-poor function (Group 4), 19% had high pain or poor function (Groups 2–3), and 5% had little pain-and-high function prior to TKR (Group 1). In Group 1, 86% were constantly aware of their knee problem, 48% reported pain daily yet 5% experienced severe or extreme pain-on-stairs, 1% pain-in-bed. Over half had a lot of limitations in vigorous activities. Compared with Group 4, Group 1 were older, less obese, more educated, and included more men and people reporting being healthy, less disabled, and happy (p<0.05 for all).
Conclusion
The majority of patients undergoing TKRs had significant pain and/or poor function. Our results provide critical information given the current debate of potentially inappropriate TKR utilization in the US.