Progression of chronic pain and associated health-related quality of life and healthcare resource use over 5 years after total knee replacement: evidence from a cohort study

Chronic pain at 1-year following knee arthroplasty is associated with a worse joint-specific function and health-related quality of life

PURPOSE

The purpose of this study was to identify independent variables associated with chronic pain (CP) at 1 year following knee arthroplasty (KA) and whether this influenced functional outcomes.

METHODS

This retrospective study was conducted over a 2-year period and included 2588 patients with completed Oxford knee score (OKS) and EuroQol (EQ)-five domains (5D) preoperatively and at 1 and 2 years postoperatively. The OKS pain component score was used to define patients with CP (≤14 points). The mean age was 70.0 (range 34-94) years and there were 1553 (60.0%) females.

RESULTS

There were 322 (12.4%) patients with CP at 1 year. A worse preoperative EQ-5D (p = 0.025), EQ-visual analogue scale (VAS) (p = 0.005) and OKS questions relating to washing (p = 0.010), limping (p = 0.007), kneeling (p = 0.003) and night pain (p = 0.004) were independently associated with risk of CP. However, the preoperative OKS (area under the curve [AUC]: 72.0, p < 0.001) and EQ-5D score (AUC: 70.1, p < 0.001) were the most reliable predictors, with threshold values of <18-points and <0.300 being predictive of CP, respectively. Of those with CP at 1 year, 231 were followed up at 2 years, of which 92 (39.8%) had resolution of their CP. A worse response to OKS question 11 (ability to shop) and EQ-5D (p = 0.028) at 1 year was independently associated with persistent CP. Patients with CP had significantly (p < 0.001) worse OKS, EQ-5D and EQ-VAS at 1 year compared to those without. However, for those that had resolution of their CP at 2 years, their outcomes were clinically equal to those that did not have CP at 1 year.

CONCLUSION

One in eight patients had CP at 1 year following surgery, which was associated with clinically worse knee-specific outcomes and quality of life. However, by 2 years, two in five patients had resolution of their CP and had functional outcomes clinically equal to those without CP at 1 year. The risk factors identified could be used to inform patients of their risk for CP and the potential for resolution.

LEVEL OF EVIDENCE

Level III retrospective study.

Prevalence and patterns of neuropathic pain in people with chronic post-surgical pain after total knee arthroplasty

Aims

The aim of this study was to describe the prevalence and patterns of neuropathic pain over one year in a cohort of patients with chronic post-surgical pain at three months following total knee arthroplasty (TKA).

Methods

Between 2016 and 2019, 363 patients with troublesome pain, defined as a score of ≤ 14 on the Oxford Knee Score pain subscale, three months after TKA from eight UK NHS hospitals, were recruited into the Support and Treatment After Replacement (STAR) clinical trial. Self-reported neuropathic pain and postoperative pain was assessed at three, nine, and 15 months after surgery using the painDETECT and Douleur Neuropathique 4 (DN4) questionnaires collected by postal survey.

Results

Symptoms of neuropathic pain were common among patients reporting chronic pain at three months post-TKA, with half reporting neuropathic pain on painDETECT (191/363; 53%) and 74% (267/359) on DN4. Of those with neuropathic pain at three months, half continued to have symptoms over the next 12 months (148/262; 56%), one-quarter had improved (67/262; 26%), and for one-tenth their neuropathic symptoms fluctuated over time (24/262; 9%). However, a subgroup of participants reported new, late onset neuropathic symptoms (23/262; 9%). Prevalence of neuropathic symptoms was similar between the screening tools when the lower cut-off painDETECT score (≥ 13) was applied. Overall, mean neuropathic pain scores improved between three and 15 months after TKA.

Conclusion

Neuropathic pain is common in patients with chronic pain at three months after TKA. Although neuropathic symptoms improved over time, up to half continued to report painful neuropathic symptoms at 15 months after TKA. Postoperative care should include screening, assessment, and treatment of neuropathic pain in patients with early chronic postoperative pain after TKA.

Modelled cost-effectiveness analysis of the Support and Treatment After Replacement (STAR) care pathway for chronic pain after total knee replacement compared with usual care

BACKGROUND

The aim of the study was to estimate the long-term cost-effectiveness of the Support and Treatment After Replacement (STAR) care pathway for chronic pain after total knee replacement compared with usual postoperative care.

METHODS

Study design: A decision-analytic (cohort Markov) model was used for the simulation with time dependent annual transition probabilities and a time horizon of five years.

SETTING

Patients treated by National Health Service (NHS) hospitals in England and Wales.

STUDY POPULATION

Adults classified as having chronic pain three months after undergoing a total knee replacement.

INTERVENTION

The STAR care pathway following a total knee replacement.

COMPARATOR

Usual postoperative care following a total knee replacement.

PERSPECTIVE

The study was undertaken from the perspective of the NHS.

OUTCOME MEASURES

Quality-adjusted life years and healthcare costs. Discounting: A rate of 3.5% for both costs and health utility.

RESULTS

Model results indicate that the STAR intervention would dominate current practice by providing a gain in quality-adjusted life years (QALYs) of 0.086 and a reduction of £375 (per person) in costs over the first five years. The incremental net monetary benefit of the STAR intervention was estimated at £2,086 (at a threshold of £20,000 per QALY). Probabilistic sensitivity analysis suggests the STAR intervention is likely to be cost-effective with a probability of 0.62. The results remain robust to changes in model assumptions on comparator utility and the timing of the start of the intervention. If hospital admission costs are assumed not to be reduced by the STAR intervention, it would no longer be cost saving, but it would likely be cost-effective based on probabilistic sensitivity analysis (0.59).

CONCLUSION

Evidence from the economic model suggests that the STAR care pathway is likely to be cost-effective and potentially dominant from an NHS perspective.

TRIAL REGISTRATION

The STAR trial is registered with ISRCTN, ISRCTN92545361.

Improvement in functional outcome 1 year after nonsurgical multidisciplinary treatment for chronic pain after total knee arthroplasty: A prospective cohort study

PURPOSE

The purpose of this study was to evaluate a multidisciplinary intervention developed for patients with debilitating chronic pain after total knee arthroplasty (TKA) unresponsive to existing treatment options.

METHODS

A treatment-based prospective cohort study was caried out in 30 TKA patients with debilitating chronic pain at least 1 year after TKA. The treatment was a multidisciplinary intervention. Main inclusion criteria: no indication for surgery. Primary outcome was function measured by KOOS-PS, OKS, OKS-APQ and WORQ. Secondary outcome measures were pain, fear of movement, self-efficacy, quality of life (QoL), health care and pain medication use, work rehabilitation and patient satisfaction. The assessments took place pre- and directly posttreatment, at 1, 3 and 12 months follow-up. The clinical relevance was assessed by predefined minimal important clinical change (MCIC).

RESULTS

At baseline patients were on average 64.7 (±7.9) years old, 67% were female, and they had knee pain for 42 (10-360) months. The results at 12-month follow-up: first, a significant improvement was shown in function, pain, fear of movement, self-efficacy and QoL. Second, in 38.5%-69.2% of patients clinical relevant improvement was shown for functional outcome, 31% for pain, and 50% for self-efficacy. Third, 42% of patients reported 'no healthcare use in the past three months'.

CONCLUSION

One year after a multidisciplinary treatment a clinically relevant improvement was shown in terms of function, pain, self-efficacy and QoL. It seems to be a promising treatment option in this difficult-to-treat patient group with debilitating chronic pain after TKA. Future research should examine the effect of the treatment in a larger study population, considering a control group, and focusing on the working population and evaluating cost-efficacy.

LEVEL OF EVIDENCE

Level II.

Factors associated with pain and functional impairment five years after total knee arthroplasty: a prospective observational study

BACKGROUND

Few studies have evaluated the associations between preoperative factors and pain and physical function outcomes after total knee arthroplasty (TKA) from a mid-term perspective. Identification of such factors is important for optimizing outcomes following surgery. Thus, we examined the associations between selected preoperative factors and moderate to severe pain and pain-related functional impairment as measured using the Brief Pain Inventory (BPI), five years after TKA in patients with knee osteoarthritis.

METHODS

In this prospective observational study, all patients scheduled for primary unilateral TKA for osteoarthritis were consecutively recruited. Preoperative factors identified from previous meta-analyses were included to assess their associations with pain severity and pain-related functional impairment five years after TKA. Pain severity was the primary outcome, while pain-related functional impairment was the secondary outcome. The BPI was used to evaluate outcomes five years post-TKA. Statistically significant factors from univariate regressions were entered into a multiple logistic regression model to identify those with the strongest associations with pain severity or pain-related functional impairment five years after TKA.

RESULTS

A total of 136 patients were included, with a mean age of 67.7 years (SD 9.2) and a majority being female (68%). More severe preoperative pain (OR = 1.34, 95% CI [1.03 to 1.74]), more painful sites (OR = 1.28., 95% CI [1.01 to 1.63]), and more severe anxiety symptoms (OR = 1.14., 95% CI [1.01 to 1.28]) were associated with increased likelihood of moderate to severe pain five years after TKA surgery, while more severe osteoarthritis (OR = 0.13, 95% CI [0.03 to 0.61]) was associated with reduced likelihood of moderate to severe pain five years after TKA. More severe anxiety symptoms (OR = 1.25, 95% CI [1.08 to 1.46]) were also associated with increased likelihood of moderate to severe pain-related functional impairment five years after surgery, while male sex (OR = 0.23, 95% CI [0.05 to 0.98]) was associated with reduced likelihood of pain-related functional impairment five years after surgery.

CONCLUSION

The identified preoperative factors should be included in larger prognostic studies evaluating the associations between preoperative factors and mid-term pain severity and physical function outcomes after TKA surgery.

Physical activity and health-related quality of life of patients with chronic knee pain after total knee replacement: Analysis of the PEP-TALK trial

BACKGROUND

Chronic pain is a major challenge for some people after total knee replacement (TKR). The changing impact of this complication during the first post-operative year remains unclear. This analysis aimed to examine how physical activity and health-related quality of life (HRQoL) evolved over the first year after TKR for patients with and without post-operative chronic knee pain.

METHODS

We conducted a secondary analysis of data from a randomised controlled trial (PEP-TALK), which tested the effectiveness of a behaviour change physiotherapy intervention compared with usual rehabilitation after TKR. Mean UCLA Activity Score and EQ-5D-5L for participants with and without chronic knee pain (14 points or lower in the Oxford Knee Score Pain Subscale (OKS-PS) at six months post-TKR) were compared at six and 12 months post-TKR.

RESULTS

Data from 83 participants were analysed. For those with chronic knee pain, UCLA Activity Score remained unchanged between baseline to six months (mean: 3.8 to 3.8), decreasing at 12 months (3.0). Those without post-operative chronic knee pain reported improved physical activity from baseline to six months (4.0 vs 4.9), plateauing at 12 months (4.9). Participants with chronic knee pain reported lower baseline HRQoL (0.28 vs 0.48). Both groups improved health utility over one year. Of those without chronic pain at six months, 8.5% returned to chronic pain by 12 months.

CONCLUSIONS

Monitoring clinical outcomes after six months may be indicated for those at risk of chronic pain post-TKR. Further, sufficiently powered analyses are warranted to increase the generalisability of this exploratory analyses' results.

Patient-Relevant Outcomes Following First Revision Total Knee Arthroplasty, by Diagnosis: An Analysis of Implant Survivorship, Mortality, Serious Medical Complications, and Patient-Reported Outcome Measures Utilizing the National Joint Registry Data Set

BACKGROUND

The purpose of this study was to investigate patient-relevant outcomes following first revision total knee arthroplasties (rTKAs) performed for different indications.

METHODS

This population-based cohort study utilized data from the United Kingdom National Joint Registry, Hospital Episode Statistics Admitted Patient Care, National Health Service Patient-Reported Outcome Measures, and the Civil Registrations of Death. Patients undergoing a first rTKA between January 1, 2009, and June 30, 2019, were included in our data set. Patient-relevant outcomes included implant survivorship (up to 11 years postoperatively), mortality and serious medical complications (up to 90 days postoperatively), and patient-reported outcome measures (at 6 months postoperatively).

RESULTS

A total of 24,540 first rTKAs were analyzed. The patient population was 54% female and 62% White, with a mean age at the first rTKA of 69 years. At 2 years postoperatively, the cumulative incidence of re-revision surgery ranged from 2.7% (95% confidence interval [CI], 1.9% to 3.4%) following rTKA for progressive arthritis to 16.3% (95% CI, 15.2% to 17.4%) following rTKA for infection. The mortality rate at 90 days was highest following rTKA for fracture (3.6% [95% CI, 2.5% to 5.1%]) and for infection (1.8% [95% CI, 1.5% to 2.2%]) but was <0.5% for other indications. The rate of serious medical complications requiring hospital admission within 90 days was highest for patients treated for fracture (21.8% [95% CI, 17.9% to 26.3%]) or infection (12.5% [95% CI, 11.2% to 13.9%]) and was lowest for those treated for progressive arthritis (4.3% [95% CI, 3.3% to 5.5%]). Patients who underwent rTKA for stiffness or unexplained pain had some of the poorest postoperative joint function (mean Oxford Knee Score, 24 and 25 points, respectively) and had the lowest proportion of responders (48% and 55%, respectively).

CONCLUSIONS

This study found large differences in patient-relevant outcomes among different indications for first rTKA. The rate of complications was highest following rTKA for fracture or infection. Although rTKA resulted in large improvements in joint function for most patients, those who underwent surgery for stiffness and unexplained pain had worse outcomes.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Advances in the management of persistent pain after total knee arthroplasty

PURPOSE OF REVIEW

Total knee arthroplasty (TKA) is one of the most commonly performed surgical procedures, with additional growth anticipated as the US population ages. Because the prevalence of chronic postsurgical pain ranges from 15 to 25%, identifying persons at risk for persistent pain following surgery allows for preoperative optimization of risk factors as well as early identification and intervention in the postsurgical period.

RECENT FINDINGS

Clinical understanding of available management techniques is critical to management, which should focus on improving patient mobility and satisfaction while reducing patient disability and healthcare costs. Current evidence supports a multimodal management strategy. This includes pharmacologic and nonpharmacologic interventions, procedural techniques, and identification and optimization of psychosocial and behavioral contributors to chronic pain. Procedural techniques known to confer analgesia include radiofrequency and watercooled neurotomy techniques. More recently, case reports have been published describing analgesic benefit with central or peripheral neuromodulation as a novel, though more invasive analgesic therapy.

SUMMARY

Identification and early intervention to address persistent pain after TKA is important to optimize patient outcomes. The anticipated growth in TKA underscores the need for future investigations to more fully define potential therapies for chronic pain following TKA.

"I am accustomed to something in my body causing pain": a qualitative study of knee replacement non-improvers' stories of previous painful and stressful experiences

BACKGROUND

Approximately 20% of total knee arthroplasty patients experience persistent postsurgical pain one year after surgery. No qualitative studies have explored previous stories of painful or stressful life experiences in patients experiencing persistent postsurgical pain after total knee replacement. This study aimed to explore stories of previous painful or stressful experiences in life in a cohort of patients that reported no improvement in pain one year after total knee arthroplasty.

METHODS

The study employed an explorative-descriptive qualitative design. Data was collected through semi-structured interviews five to seven years after surgery, with patients who reported no improvement in pain-related interference with walking 12 months after total knee replacement. The data was analyzed using qualitative content analysis.

RESULTS

The sample consisted of 13 women and 10 men with a median age of 67 years at the time of surgery. Prior to surgery, six reported having at least one chronic illness and 16 reported having two or more painful sites. Two main themes were identified in the data analysis: Painful years - the burden of living with long lasting pain, and the burden of living with psychological distress.

CONCLUSIONS

The participants had severe longlasting knee pain as well as longlasting pain in other locations, in addition to experiences of psychologically stressful life events before surgery. Health personnel needs to address the experience and perception of pain and psychological struggles, and how it influences patients' everyday life including sleeping routines, work- and family life as well as to identify possible vulnerability for persistent postsurgical pain. Identifying and assessing the challenges enables personalized care and support, such as advice on pain management, cognitive support, guided rehabilitation, and coping strategies both pre-and post-surgery.

Trajectories of Pain and Function Outcomes up to 5 to 8 Years Following Total Knee Arthroplasty

BACKGROUND

There appears to be substantial variability in outcomes > 2 years following total knee arthroplasty (TKA) that is masked by whole group analyses. The goal of the study was to identify trajectories of pain and function outcomes up to 5 to 8 years post-TKA and to identify baseline factors that are associated with different trajectories of recovery.

METHODS

Baseline, 6-month, and 12-month pain and function data were collected in a previous study investigating predictors of outcome following primary TKA (n = 286), along with a variety of baseline predictor variables. The present study obtained pain and function data at 5 to 8 years following TKA in the same cohort (n = 201). Latent class linear mixed models were used to identify different classes of pain and functional trajectories over time. The extent to which differences across latent classes were explained by baseline predictor variables was determined.

RESULTS

Three classes of pain and two classes of function trajectory were identified. While most patients (84% to 93%) followed a trajectory that showed an initial rapid gain following surgery that was sustained through 5 to 8 years, both pain and function included at least one trajectory class that showed a meaningful change after 12 months. No predictor variables were significantly associated with either the pain or function classes.

CONCLUSIONS

Most patients follow a traditional trajectory of recovery in knee pain and function over 5 to 8 years. However, alternative trajectories are observed in an important minority of patients such that knee pain and function at 12 months after surgery does not always reflect outcomes at 5 to 8 years.

A Linear Decomposition Approach to Explain Excess Direct Healthcare Expenditures Associated with Pain Among Adults with Osteoarthritis

Objective:

Many patients with osteoarthritis experience pain which can lead to higher healthcare expenditures. It is important to understand the factors that drive the excess expenditures associated with pain in osteoarthritis.

Design:

Cross-sectional.

Study sample:

Our study sample consisted of adults (age ⩾ 18 years) from the Medical Expenditure Panel Survey (MEPS, 2018).

Methods:

Adults who were alive during the calendar year and had pain status were included in this study (N = 2804 weighted N = 32.03 million). Osteoarthritis was identified from the medical conditions file and household file. We used multivariable ordinary least squares regression to identify the statistically significant association of pain with direct healthcare expenditures. The Blinder-Oaxaca post-linear decomposition on log-transformed total direct healthcare expenditures was used to estimate the extent to which differences in characteristics contribute to the excess expenditures associated with pain.

Results:

Adults with osteoarthritis and pain had higher average expenditures ($21 814 vs $10 827, P < .001; 9.318 vs 8.538 in logtransformed expenditures) compared to those without pain. Pooled regression weights explained 62.9% of excess expenditures differences in characteristics between the 2 groups. The 2 main drivers of excess healthcare expenditures among adults with osteoarthritis and pain were (i) comorbidities (diabetes, asthma, chronic obstructive pulmonary disease, depression, heart diseases, cancer, and non-cancer pain conditions and (ii) prescription medications (NSAIDs, opioids, and polypharmacy).

Conclusion:

Need factors such as comorbid conditions, and prescription treatment explained the excess healthcare expenditures among adults with osteoarthritis and pain. The study findings suggest that reducing polypharmacy and appropriate management of comorbid conditions may be a pathway to reduce excess expenditures among adults with osteoarthritis and pain.