Session Type: ACR Concurrent Abstract Session
Session Time: 2:30PM-4:00PM
Background/Purpose: Total knee arthroplasty (TKA) is a common elective surgery to treat pain and functional limitation due to refractory arthritis. Post-operative pain is commonly underestimated and undertreated, which can prolong hospital stay, and interfere with engagement in rehabilitation exercises and lead to poorer health-related quality of life (HRQOL). Our objectivewas to examine if immediate post-arthroplasty pain trajectory (pain scores plotted from pre-operative to all time-points post-operative) is associated with long-term pain outcome after total knee arthroplasty (TKA), and assess important correlates of pain trajectories.
Methods: We used the data from the pain sub-study of the FORCE-TJR study, a nationally representative cohort of U.S. patients (n =28,000) undergoing TKA (or hip arthroplasty) from more than 150 surgeons in 22 states. In a sub-study, patients evaluated pain severity at 2- and 8-weeks after index TKA using a validated survey; pain was assessed on a 0-10 numeric rating scale (NRS). We used group-based trajectory models to determine the number and shape of short-term pain (baseline, 2 weeks, and 8 weeks post-op) trajectories. We then examined the predictive ability of these short-term pain trajectory for longer-term pain outcomes at 6 and 12 months, using multiple linear regression analyses with logit function. Outcomes were Knee injury and Osteoarthritis Outcome Score (KOOS) pain at 6 and 12-months (higher score, worse pain). Multivariable logistic regression adjusted for age, gender, body mass index (BMI), race, Charlson Comorbidity count, and pre-operative health-related quality of life as measured by the SF-36 physical health (PCS) and mental health (MCS) scores.
Results: 659 TKA patients provided 2-week and 8-week pain survey data. The majority of respondents were female (64.5%) and at least 65 years old (66.5%). Among respondents two pain trajectories were evident, with majority being pain responders (72%); i.e. pain decreased in a meaningful way after TKA compared to pre-operative pain) and a smaller proportion were pain non-responders (28%). Early pain trajectory was highly significantly associated with 6- and 12-month pain outcome on KOOS. Additional factors significantly associated at 6 and 12 months were, Charlson Comorbidity count 3, and pre-operative PCS and MCS. African American/other race was significantly associated with pain outcome at 6 months, but not 12 months. Gender, age, and BMI were not significantly associated with pain trajectory at either 6- or 12-months.
Conclusion: We found that pain trajectory up to 8-weeks post-TKA surgery independently predicted longer-term pain outcome. Interventions to modify early post-operative pain experience may lead to better pain outcome (and other patient-reported outcomes) after TKA. Table 1. Predictors of 6- and 12-month KOOSpain scale after TKA among members of FORCE-TJR
|Coefficient||95% CI; p-value||Coefficient||95% CI; p-value|
|Non-responder Pain Trajectory||-11.83||-14.48, 9.17; p<0.001||-10.22||-13.98, -6.46; p<0.001|
|Age||0.06||-0.08,0.21;p=0.42||0.05||-0.16, 0.27; p=0.63|
|Gender (Female)||1.82||-0.71, 4.35; p=0.42||1.48||-1.94, 4.91; p=0.40|
|25<30||0.30||-3.45, 4.06; p=0.87||-1.75||-7.02, 3.51; p=0.51|
|30<35||1.52||-2.30,5.33;p=0.44||-1.17||-6.45, 4.12; p=0.67|
|≥35||1.16||-3.00, 5.32; p=0.59||0.96||-4.79, 6.71; p=0.74|
|African American/Others||-5.73||-10.88, -0.57; p=0.03||1.66||-6.64, 9.95; p=0.69|
|Charlson Comorbidity Count|
|1||-1.42||-4.28, 1.44; p=0.33||-2.94||-6.73, 0.86; p=0.13|
|2||-1.89||-6.13, 2.35; p=0.38||3.72||-2.17, 9.62; p=0.22|
|>= 3||-7.63||-12.84, -2.42; p<0.001||1.16||-5.99, 8.31; p=0.75|
|Pre‐op SF-36 MCS||0.30||0.15, 0.45; p<0.001||0.39||0.19, 0.60; p<0.001|
|Pre‐op SF-36 PCS||0.31||0.21, 0.42; p<0.001||0.32||0.18, 0.47; p<0.001|
To cite this abstract in AMA style:Singh JA, Nobel L, Weissman N, Saag KG, Foster PJ, Allison JJ, Lemay C, Franklin PD. Post-Arthroplasty Pain Trajectories after Total Knee Arthroplasty and Their Association with 6- and 12-Month Pain [abstract]. Arthritis Rheumatol. 2016; 68 (suppl 10). https://acrabstracts.org/abstract/post-arthroplasty-pain-trajectories-after-total-knee-arthroplasty-and-their-association-with-6-and-12-month-pain/. Accessed January 20, 2021.
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