Background

One in five patients experience chronic pain 12 months following total knee arthroplasty (TKA). This longitudinal study used a person-centred approach to identify subgroups of patients with distinct chronic pain profiles following TKA and identified preoperative characteristics associated with these profiles.

Methods

On the day before surgery, 202 patients completed questionnaires that assessed pain, interference with functioning, fatigue, anxiety, depression and illness perceptions. Average and worst pain were assessed prior to surgery, on postoperative day 4, at 6 week and at 3 and 12 months following surgery. Using growth mixture modelling, two subgroups with distinct average and worst pain profiles were identified.

Results

Patients in the "lower average" and "lower worst" pain classes had moderate preoperative pain scores that decreased over the remaining 9 months following TKA. Patients in the "higher average" and "higher worst" pain classes had relatively higher preoperative pain scores that increased during the first three months and then decreased slightly over the remaining 9 months. Patients in the higher pain classes had higher interference with function scores; used opioids prior to surgery more often, were more likely to receive a continuous nerve block and ketamine; had higher preoperative fatigue severity and interference scores; and had worse perceptions of illness than patients in the lower pain classes.

Conclusions

These risk factors may be used to identify subgroups of patients at higher risk for more severe pain after TKA. Future studies should test whether modifying these risk factors can improve patients' outcomes after TKA.

Significance statement

The present study provides a novel and original analysis of pain profiles following total knee arthroplasty that may contribute to our understanding of the transition from acute to chronic pain. Our results may be used to identify patients at higher risk for poorer outcomes based on preoperative risk factors.

OBJECTIVES:One in five patients does not improve in pain with walking (non-responders) 12 months after total knee arthroplasty (TKA). This longitudinal study investigated a broad range of symptoms before and after TKA and evaluated possible differences in symptom distress between responders and non-responders with regards to pain with walking after TKA. METHODS:Prior to TKA surgery, 182 patients completed a demographic questionnaire and the Memorial Symptom Assessment Scale-Short Form (MSAS-SF). The MSAS-SF was repeated 12 months following TKA. Clinical data were extracted from medical records. Patients were categorized as responders or non-responders based on their trajectories of pain with walking assessed prior to surgery, on postoperative day 4, at 6 weeks, and at 3 and 12 months. RESULTS:Overall, the most distressful preoperative symptoms were pain, lack of energy, difficulty sleeping, feeling drowsy, worrying, feeling bloated, and problems with sexual interest or activity. However, compared with patients classified as responders to TKA, non-responders had higher total symptom distress scores both preoperatively and 12 months postoperatively. Preoperatively, non-responders scored higher than responders on five of the seven most distressing symptoms (i.e., all except difficulty sleeping and feeling bloated), and 12 months postoperatively, non-responders scored higher than responders on six of the seven most distressing symptoms (i.e., all but feeling bloated). In a multivariate analysis, higher preoperative distress scores for pain and problems with sexual interest or activity were significant predictors of non-response to TKA, controlling for other relevant factors. CONCLUSIONS:Patients' preoperative symptom burden may be a useful indicator of their risk for non-improvement following TKA surgery. Future studies need to evaluate the effect of reducing patients' preoperative symptom burden on TKA outcomes.

Background

Moderate/severe pain after total knee arthroplasty (TKA) is a poor surgical outcome. Many studies have identified preoperative risk factors of pain after TKA, but studies of the joint contributions of co-occurring symptoms are lacking.

Methods

Patients undergoing primary TKA (n = 202) were enrolled in a longitudinal cohort study. Preoperatively, patients completed questionnaires measuring demographics and symptoms (pain, fatigue, sleep problems and depression). Pain was re-assessed 12 months after TKA. Logistic regression analysis was used to compute the probabilities of moderate-severe pain at 12 months based on preoperative symptom levels, and results were combined into a risk matrix.

Results

More than one-third (40%) of patients (n = 187) reported moderate-severe pain after TKA. Among preoperative risk factors included in the logistic regression analyses were age, sex, pain, fatigue, sleep problems and depression. Adjusting for possible confounders, fatigue (p = 0.02) and pain (p = 0.01) were significant risk factors for moderate-severe pain at 12-months follow-up and were retained in the final risk matrix. The co-occurrence of high-preoperative fatigue and pain scores resulted in 57% estimated probability of moderate-severe pain at 12 months. Similarly, the co-occurrence of low-preoperative fatigue and pain scores resulted in 14% estimated probability of moderate-severe pain 12 months after TKA.

Conclusion

The combination of high fatigue and pain scores prior to surgery was a key risk factor for moderate-severe pain 12 months after TKA. Mapping of these factors could be used preoperatively to identify patients who are at risk to experience a poor outcome of TKA.

Main objective

Systematically review and synthesize preoperative and intraoperative factors associated with pain after total knee arthroplasty (TKA) in patients with osteoarthritis.

Methods

Based on a peer-reviewed protocol, we searched Medline, Embase, CINAHL, Cochrane Library, and PEDro for prospective observational studies (January 2000 to February 2023) investigating factors associated with pain after TKA. The primary outcome was pain twelve months after TKA. Pain at three and six months were secondary outcomes. Multivariate random-effects meta-analyses were used to estimate mean correlation (95% CIs) between factors and pain. Sensitivity analysis was performed for each risk of bias domain and certainty of evidence was assessed.

Results

Of 13,640 studies, 29 reports of 10,360 patients and 61 factors were analysed. The mean correlation between preoperative factors and more severe pain at twelve months was estimated to be 0.36 (95% CI, 0.24, 0.47; P < .000; moderate-certainty evidence) for more catastrophizing, 0.15 (95% CI; 0.08, 0.23; P < .001; moderate-certainty evidence) for more symptomatic joints, 0.13 (95% CI, 0.06, 0.19; P < .001; very low-certainty evidence) for more preoperative pain. Mean correlation between more severe radiographic osteoarthritis and less pain was -0.15 (95% CI; -0.23, -0.08; P < .001; low-certainty evidence). In sensitivity analysis, the estimated correlation coefficient for pain catastrophizing factor increased to 0.38 (95% CI 0.04, 0.64). At six and three months, more severe preoperative pain was associated with more pain. Better preoperative mental health was associated with less pain at six months.

Conclusion and relevance

More pain catastrophizing, more symptomatic joints and more pain preoperatively were correlated with more pain, while more severe osteoarthritis was correlated with less pain one year after TKA. More preoperative pain was correlated with more pain, and better mental health with less pain at six and three months. These findings should be further tested in predictive models to gain knowledge which may improve TKA outcomes.

Introduction

One in five patients undergoing total knee arthroplasty (TKA) experience unchanged or worse pain and physical function 1 year after surgery. Identifying risk factors for unfavourable outcomes is necessary to develop tailored interventions to minimise risk. There is a need to review more current literature with updated methodology that addresses the limitations of earlier systematic reviews and meta-analyses. We present a Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols compliant protocol for a systematic review and meta-analysis of predictors of chronic pain and impaired function after TKA.

Methods and analysis

This review will include prospective longitudinal observational studies, or randomised trials (including cluster and crossover designs) that report arm-wise predictors of chronic postsurgical pain or impaired physical function at 3 months, 6 months or 12 months. A comprehensive literature search of studies published between 2000 and 2019 will be performed in Medline, Embase, CINAHL, Cochrane Library and PEDro. Blinded assessment with consensus agreement will be applied for inclusion of studies, data extraction and assessment of bias risk (Quality in Prognosis Studies tool). The co-primary outcomes, pain and impaired function, at 12 months after TKA will be analysed separately. Estimates of association between each outcome and any preoperative or intraoperative factor that may predict chronic pain or impaired physical function will be extracted from the included studies, where possible. For randomised studies, results will only be extracted from TKA arms (or the first period of crossover trials). Estimates of association from the primary evidence will be synthesised narratively, and quantitatively using multivariate meta-analysis to provide 'pooled' estimates of association. Subgroup and sensitivity analyses will be performed. Certainty of evidence for each predictor will be derived from the Grading of Recommendations Assessment, Development and Evaluation framework.

Ethics and dissemination

No ethical issues are associated with this project. The results from this review will be published in peer-reviewed journals and presented at international conferences.

Prospero registration number

CRD42018079069.

Background

One in five patients report chronic pain following total knee arthroplasty (TKA) and are considered non-improvers. Psychological interventions such as cognitive behavioral therapy (CBT), combined with exercise therapy and education may contribute to reduced pain an improved function both for patients with OA or after TKA surgery, but the evidence for the effectiveness of such interventions is scarce. This randomized controlled trial with three arms will compare the clinical effectiveness of patient education and exercise therapy combined with internet-delivered CBT (iCBT), evaluated either as a non-surgical treatment choice or in combination with TKA, in comparison to usual treatment with TKA in patients with knee OA who are considered candidates for TKA surgery.

Methods

The study, conducted in three orthopaedic centers in Norway will include 282 patients between ages 18 and 80, eligible for TKA. Patients will be randomized to receive the exercise therapy + iCBT, either alone or in combination with TKA, or to a control group who will undergo conventional TKA and usual care physiotherapy following surgery. The exercise therapy will include 24 one hour sessions over 12 weeks led by a physiotherapist. The iCBT program will be delivered in ten modules. The physiotherapists will receive theoretical and practical training to advise and mentor the patients during the iCBT program. The primary outcome will be change from baseline to 12 months on the pain sub-scale from the Knee Injury and Osteoarthritis Outcome Score (KOOS). Secondary outcomes include the remaining 4 sub-scales from the KOOS (symptoms, function in daily living, function in sports and recreation, and knee-related quality of life), EQ-5D-5L, the Pain Catastrophizing Scale, the 30-s sit-to-stand test, 40-m walking test and ActiGraph activity measures. A cost-utility analysis will be performed using QALYs derived from the EQ-5D-5L and registry data.

Discussion

This is the first randomized controlled trial to investigate the effectiveness of exercise therapy and iCBT with or without TKA, to optimize outcomes for TKA patients. Findings from this trial will contribute to evidence-based personalized treatment recommendations for a large proportion of OA patients who currently lack an effective treatment option.

Trial registration

Clinicaltrials.gov : NCT03771430 . Registered: Dec 11, 2018.