Does pre-surgical central modulation of pain influence outcome after total knee replacement? A systematic review

Application of the IASP Grading System to Identify Underlying Pain Mechanisms in Patients With Knee Osteoarthritis: A Prospective Cohort Study

OBJECTIVES

This study aimed to apply the International Association for the Study of Pain (IASP) grading system for identifying nociplastic pain in knee osteoarthritis (KOA) awaiting total knee arthroplasty (TKA) and propose criteria to fine-tune decision-making. In addition, the study aimed to characterize a "probable" versus "no or possible" nociplastic pain mechanism using biopsychosocial variables and compare both groups in their 1-year post-TKA response.

METHODS

A secondary analysis of baseline data of a longitudinal prospective study involving 197 patients with KOA awaiting total TKA in Belgium and the Netherlands was performed. Two approaches, one considering 4 and the other 3 pain locations (step 2 of the grading system), were presented. Linear mixed model analyses were performed to compare the probable and no or possible nociplastic pain mechanism groups for several preoperative biopsychosocial-related variables and 1-year postoperative pain. Also, a sensitivity analysis, comparing 3 pain mechanism groups, was performed.

RESULTS

Thirty (15.22%-approach 4 pain locations) and 46 (23.35%-approach 3 pain locations) participants were categorized under probable nociplastic pain. Irrespective of the pain location approach or sensitivity analysis, the probable nociplastic pain group included more woman, was younger, exhibited worse results on various preoperative pain-related and psychological variables, and had more pain 1-year post-TKA compared with the other group.

DISCUSSION

This study proposed additional criteria to fine-tune the grading system for nociplastic pain (except for discrete/regional/multifocal/widespread pain) and characterized a subgroup of patients with KOA with probable nociplastic pain. Future research is warranted for further validation.

A Review of Current Approaches to Pain Management in Knee Osteoarthritis with a Focus on Italian Clinical Landscape

The global cases of knee osteoarthritis (KOA) are projected to increase by 74.9% by 2050. Currently, over half of patients remain dissatisfied with their pain relief. This review addresses unmet needs for moderate-to-severe KOA pain; it offers evidence and insights for improved management. Italian experts from the fields of rheumatology, physical medicine and rehabilitation, orthopedics, primary care, and pain therapy have identified several key issues. They emphasized the need for standardized care protocols to address inconsistencies in patient management across different specialties. Early diagnosis is crucial, as cartilage responds better to early protective and structural therapies. Faster access to physiatrist evaluation and reimbursement for physical, rehabilitative, and pharmacological treatments, including intra-articular (IA) therapy, could reduce access disparities. Concerns surround the adverse effects of oral pharmacological treatments, highlighting the need for safer alternatives. Patient satisfaction with corticosteroids and hyaluronic acid-based IA therapies reduces over time and there is no consensus on the optimal IA therapy protocol. Surgery should be reserved for severe symptoms and radiographic KOA evidence, as chronic pain post-surgery poses significant societal and economic burdens. The experts advocate for a multidisciplinary approach, promoting interaction and collaboration between specialists and general practitioners, to enhance KOA care and treatment consistency in Italy.

The influence of pain catastrophizing on pain and function after knee arthroplasty in knee osteoarthritis

Pain catastrophizing is an exaggerated focus on pain sensations. It may be an independent factor influencing pain and functional outcomes of knee arthroplasty. We aimed to evaluate the association between pre-operative pain catastrophizing with pain and function outcomes up to one year after knee arthroplasty. We used data from a cohort study of patients undergoing primary knee arthroplasty (either total or unicompartmental arthroplasty) for knee osteoarthritis. Pain catastrophizing was assessed pre-operatively using the Pain Catastrophizing scale (PCS). Other baseline variables included demographics, body mass index, radiographic severity, anxiety, depression, and knee pain and function assessed using the Western Ontario and McMaster University Index (WOMAC). Patients completed the WOMAC at 6- and 12-months after arthroplasty. WOMAC pain and function scores were converted to interval scale and the association of PCS and changes of WOMAC pain and function were evaluated in generalized linear regression models with adjustment with confounding variables. Of the 1136 patients who underwent arthroplasty (70% female, 84% Chinese, 92% total knee arthroplasty), 1102 and 1089 provided data at 6- and 12-months post-operatively. Mean (± SD) age of patients was 65.9 (± 7.0) years. PCS was associated with a change in WOMAC pain at both 6-months and 12-months (β = - 0.04, 95% confidence interval: - 0.06, - 0.02; P < 0.001) post-operatively after adjustment in multivariable models; as well as change in WOMAC function at 6-months and 12-months. In this large cohort study, pre-operative pain catastrophizing was associated with lower improvements in pain and function at 6-months and 12-months after arthroplasty.

Differences in self-reported signs related to central sensitization and pressure pain threshold related to knee osteoarthritis and sarcopenia

PURPOSE

Neuroinflammation, which occurs in knee osteoarthritis and sarcopenia, has attracted attention as a mechanism of central sensitization, but the relationship between central sensitization and these conditions has not been widely studied. This study investigates differences in self-reported signs of central sensitization and pressure pain threshold in individuals with knee osteoarthritis and sarcopenia.

METHODS

We examined 340 patients (mean age ± standard deviation: 76 ± 5.9, women were 86.9%) with knee osteoarthritis scheduled to undergo total knee arthroplasty. For comparison, 129 community-dwelling older people (mean age ± standard deviation: 76 ± 5.5, women were 68.9%) individuals without a history of knee osteoarthritis or any other diagnosed illnesses were matched for age and sex. We assessed central sensitization inventory-9, pressure pain threshold, pain-related factors, skeletal muscle mass index, and hand grip strength. ANCOVA using 2 (patients with knee osteoarthritis and community older people without knee osteoarthritis) × 2 (sarcopenia and robust) was performed to assess outcome measurements.

RESULTS

The prevalence of sarcopenia among patients with knee osteoarthritis was 50.3%. ANCOVA revealed an interaction effect for the central sensitization inventory-9. For the main effect of knee osteoarthritis, there was a significant difference in central sensitization inventory-9, and for the main effect of sarcopenia, there was a significant difference in pressure pain threshold.

CONCLUSIONS

Discrepancies in the evaluation of central sensitization were identified between knee osteoarthritis and sarcopenia. Individuals with knee osteoarthritis had elevated score of self-reported indications of central sensitization, whereas sarcopenic patients had reduced pressure pain thresholds.

Association between widespread pain and psychosocial factors in people with knee osteoarthritis: a cross-sectional study of patients from primary care in Denmark

INTRODUCTION

The relationship between psychosocial factors and bodily pain in people with knee osteoarthritis (KOA) is unclear.

PURPOSE

To examine whether widespread pain was associated with poorer self-efficacy, more anxiety, depression, and kinesiophobia in people with KOA.

METHODS

This was a cross-sectional study based on data from Good Life with osteoArthritis in Denmark (GLA:D®). The association between widespread pain (multiple pain sites) and self-efficacy (Arthritis Self-Efficacy Scale), anxiety and depression (item from the EQ-5D-5 L), and kinesiophobia (yes/no) was examined using multiple linear tobit or logistic regression models.

RESULTS

Among 19,323 participants, 10% had no widespread pain, 37% had 2 pain sites, 26% had 3-4 pain sites, and 27% had ≥5 pain sites. Widespread pain was associated with poorer self-efficacy (-0.9 to -8.3 points), and the association was stronger with increasing number of pain sites (p-value <.001). Significant increasing odds ratios (ORs) were observed for having anxiety or depression with 3-4 pain sites (OR 1.29, 95% CI 1.12; 1.49) and ≥5 pain sites (OR 1.80, 95% CI 1.56; 2.07). Having 2 and 3-4 pain sites were associated with lower odds of kinesiophobia compared to having no widespread pain.

CONCLUSION

Widespread pain was associated with lower self-efficacy and more anxiety and depression but also lower kinesiophobia in people with KOA.

[Concept for integrative pain treatment of osteoarthritis of the knee based on the evidence for conservative and complementary therapies]

BACKGROUND

Osteoarthritis of the knee (gonarthritis) represents a medical challenge.

RESEARCH QUESTION

What is the evidence with respect to approaches of complementary medicine and their integration into multimodal pain management concepts?

MATERIAL AND METHODS

Qualitative nonsystematic literature search on the epidemiology and pathophysiology as well as informative clinical trials, meta-analyses and clinical guidelines about conservative treatment including complementary therapy for gonarthritis.

RESULTS

Osteoarthritis of the knee is a frequent condition with biopsychosocial risks factors for chronification. The German S2k clinical guideline (k = consensus-based, not based on scientific systematic literature searches) published by the Association of the Scientific Medical Societies in Germany (AWMF) in 2017 has not yet been updated. The current guidelines of the American College of Rheumatology (ACR) date from 2020. Both guidelines recommend exercise therapy, weight reduction, short-term analgesics, topical therapy, intra-articular corticoid injections and acupuncture with variable strengths. Furthermore, transcutaneous electrical nerve stimulation (TENS), laser and other electrophysical therapies, shock waves, traction treatment, ergotherapy, comfrey poultices and mudpacks can also be used. Current research supports the benefits of tai chi/qigong and medicinal leaches.

CONCLUSION

Complementary treatment approaches, such as acupuncture, tai chi/qigong, topical naturopathic self-treatment and leeches (with limitations) can, in addition to behavioral changes, exercise therapy and short-term pharmacological treatment, be important evidence-based components of integrative pain management concepts, e.g. in terms of an interdisciplinary multimodal pain treatment (IMPT). Besides pain reduction and functional improvement they promote the internal control conviction through the possibility of self-treatment and self-exercise.

Prognostic Factors for Postoperative Chronic Pain after Knee or Hip Replacement in Patients with Knee or Hip Osteoarthritis: An Umbrella Review

Knee and hip osteoarthritis are highly prevalent in the older population. Management of osteoarthritis-related pain includes conservative or surgical treatment. Although knee or hip joint replacement is associated with positive outcomes, up to 30% of patients report postoperative pain in the first two years. This study aimed to synthesize current evidence on prognostic factors for predicting postoperative pain after knee or hip replacement. An umbrella review of systematic reviews was conducted to summarize the magnitude and quality of the evidence for prognostic preoperative factors predictive of postoperative chronic pain (>6 months after surgery) in patients who had received knee or hip replacement. Searches were conducted in MEDLINE, CINAHL, PubMed, PEDro, SCOPUS, Cochrane Library, and Web of Science databases from inception up to 5 August 2022 for reviews published in the English language. A narrative synthesis, a risk of bias assessment, and an evaluation of the evidence confidence were performed. Eighteen reviews (nine on knee surgery, four on hip replacement, and seven on both hip/knee replacement) were included. From 44 potential preoperative prognostic factors, just 20 were judged as having high or moderate confidence for robust findings. Race, opioid use, preoperative function, neuropathic pain symptoms, pain catastrophizing, anxiety, other pain sites, fear of movement, social support, preoperative pain, mental health, coping strategies, central sensitization-associated symptoms, and depression had high/moderate confidence for an association with postoperative chronic pain. Some comorbidities such as heart disease, stroke, lung disease, nervous system disorders, and poor circulation had high/moderate confidence for no association with postoperative chronic pain. This review has identified multiple preoperative factors (i.e., sociodemographic, clinical, psychological, cognitive) associated with postoperative chronic pain after knee or hip replacement. These factors may be used for identifying individuals at a risk of developing postoperative chronic pain. Further research can investigate the impact of using such prognostic data on treatment decisions and patient outcomes.

Subcortical brain anatomy as a potential biomarker of persistent pain after total knee replacement in osteoarthritis

ABSTRACT

The neural mechanisms for the persistence of pain after a technically successful arthroplasty in osteoarthritis (OA) remain minimally studied, and direct evidence of the brain as a predisposing factor for pain chronicity in this setting has not been investigated. We undertook this study as a first effort to identify presurgical brain and clinical markers of postarthroplasty pain in knee OA. Patients with knee OA (n = 81) awaiting total arthroplasty underwent clinical and psychological assessment and brain magnetic resonance imagining. Postoperative pain scores were measured at 6 months after surgery. Brain subcortical anatomic properties (volume and shape) and clinical indices were studied as determinants of postoperative pain. We show that presurgical subcortical volumes (bilateral amygdala, thalamus, and left hippocampus), together with shape deformations of the right anterior hippocampus and right amygdala, associate with pain persistence 6 months after surgery in OA. Longer pain duration, higher levels of presurgical anxiety, and the neuropathic character of pain were also prognostic of postsurgical pain outcome. Brain and clinical indices accounted for unique influences on postoperative pain. Our study demonstrates the presence of presurgical subcortical brain factors that relate to postsurgical persistence of OA pain. These preliminary results challenge the current dominant view that mechanisms of OA pain predominantly underlie local joint mechanisms, implying novel clinical management and treatment strategies.

Exploratory analysis of 5 supervised machine learning models for predicting the efficacy of the endogenous pain inhibitory pathway in patients with musculoskeletal pain

OBJECTIVES

The identification of factors that influence the efficacy of endogenous pain inhibitory pathways remains challenging due to different protocols and populations. We explored five machine learning (ML) models to estimate the Conditioned Pain Modulation (CPM) efficacy.

DESIGN

Exploratory, cross-sectional design.

SETTING AND PARTICIPANTS

This study was conducted in an outpatient setting and included 311 patients with musculoskeletal pain.

METHODS

Data collection included sociodemographic, lifestyle, and clinical characteristics. CPM efficacy was calculated by comparing the pressure pain thresholds before and after patients submerged their non-dominant hand in a bucket of cold water (cold-pressure test) (1-4 °C). We developed five ML models: decision tree, random forest, gradient-boosted trees, logistic regression, and support vector machine.

MAIN OUTCOME MEASURES

Model performance were assessed using receiver operating characteristic curve (AUC), accuracy, sensitivity, specificity, precision, recall, F1-score, and the Matthews Correlation Coefficient (MCC). To interpret and explain the predictions, we used SHapley Additive explanation values and Local Interpretable Model-Agnostic Explanations.

RESULTS

The XGBoost model presented the highest performance with an accuracy of 0.81 (95% CI = 0.73 to 0.89), F1 score of 0.80 (95% CI = 0.74 to 0.87), AUC of 0.81 (95% CI: 0.74 to 0.88), MCC of 0.61, and Kappa of 0.61. The model was influenced by duration of pain, fatigue, physical activity, and the number of painful areas.

CONCLUSIONS

XGBoost showed potential in predicting the CPM efficacy in patients with musculoskeletal pain on our dataset. Further research is needed to ensure the external validity and clinical utility of this model.

Comparison of the effects of preoperative celecoxib and gabapentin on pain, functional recovery, and quality of life after total knee arthroplasty: A randomized controlled clinical trial

Background

Acute pain is one of the main complaints of patients after total knee arthroplasty (TKA), which causes delayed mobility, increased morphine consumption, and subsequently increased costs. Therefore, the present study was performed to evaluate the preventive effect of preoperative celecoxib and gabapentin on reducing patient pain as a primary outcome after TKA surgery.

Materials and Methods

This randomized, double-blind controlled clinical trial was performed on 270 patients with osteoarthritis that were candidates for TKA surgery allocated into three groups. In the first group, 900 mg of gabapentin was administered orally on a daily basis for 3 days before surgery. In the second group, 200 mg of oral celecoxib was administered twice daily for 3 days before surgery. In the third group, oral placebo was administered twice daily for 3 days before the surgery. The patients' pain score and knee and its functional score were recoded.

Results

The mean of reduction pain in gabapentin and celecoxib groups was significantly lower than that of the control group at 12, 24, and 48 h after surgery (P < 0.001); however, two groups were not significantly different from each other (P > 0.05). Furthermore, the two medication groups were not significantly different in this regard (P > 0.05). In addition, the knee score in the gabapentin group with the means of 85.40 ± 5.47 and the celecoxib group with the means of 87.03 ± 3.97 were significantly higher than those of the control group with the means of 78.90 ± 4.39 in the 1^st month after the surgery (P < 0.001).

Conclusion

According to the results of the present study, the preventive administration of gabapentin and celecoxib showed a significant and similar effectiveness on reducing patient pain after TKA surgery and on improving the KSS and quality of life scores.

Neuropathic-like symptoms and central sensitization related signs and symptoms negatively affect the functional performance of patients with knee osteoarthritis – a cross-sectional study

Objective

This study aimed to compare the functional performance among participants with a neuropathic-like symptoms (NS) and central sensitization related signs and symptoms (CS), and their knee osteoarthritis (OA) counterparts.

Methods

A cross-sectional observational study was conducted with 125 participants with knee OA (94 females, mean age 63.1 ​± ​7.4 years). Participants completed a self-reported questionnaire with personal and clinical features and musculoskeletal pain characteristics, including NS (PainDETECT), CS (Central Sensitization Inventory, CSI), and conditioned pain modulation. Self-reported functional disability (Western Ontario and McMaster Universities Osteoarthritis Index, WOMAC) and functional mobility (Timed Up and Go, TUG) were compared among patients with NS, CS, and their knee OA counterparts using the one-way analysis of variance (ANOVA).

Results

Thirty-three (26.4%) participants had NS and CS, eighteen (14.4%) had NS, twenty-seven (21.6%) participants had CS, and 47 (37.6%) had knee OA with no NS or CS. A one-way ANOVA revealed greater functional limitation in the group with NS and CS (mean ​= ​67.5 ​± ​12.0) or NS (mean ​= ​56.7 ​± ​17.5) than the group without these symptoms (mean ​= ​32.0 ​± ​20.7) with a statistical significance difference [F(3, 121) ​= ​29.434, p ​< ​0.001] in the WOMAC Total score. The group with NS and CS (mean ​= ​19.2 ​± ​7.4) or NS (mean ​= ​16.3 ​± ​6.3) had slower velocity than the group without these symptoms (mean ​= ​11.6 ​± ​3.5) with a statistical significance difference [F(3,121) ​= ​10.045, p ​< ​0.001] in the TUG test.

Conclusion

Participants with knee osteoarthritis and NS or CS pain phenotype have greater functional limitations than their counterparts.

Prehabilitation before total knee arthroplasty: A systematic review on the use and efficacy of stratified care

BACKGROUND

Preoperative rehabilitation (hereafter called "prehabilitation") has been proposed as a potentially effective treatment to target preoperative risk factors to prevent insufficient outcome after total knee arthroplasty (TKA).

PURPOSE

We aimed to assess whether previous clinical trials of non-surgical, non-pharmacological prehabilitation in individuals with knee osteoarthritis (KOA) awaiting TKA focused on specific clinical phenotypes or specific individual characteristics and whether the content of the prehabilitation was stratified accordingly. Second, we aimed to summarize and compare the long-term effects of stratified and non-stratified care on pain, satisfaction, function and quality of life.

METHODS

A systematic literature search of PubMed, Web of Science, Scopus and Embase was performed. All relevant articles published up to April 19, 2021 reporting "(randomized controlled) clinical trials or prospective cohort studies" (S) related to the key words "total knee arthroplasty" (P), "preoperative conservative interventions" (I), "pain, function, quality of life and/or satisfaction" (O) were included.

RESULTS

After screening 3498 potentially eligible records, 18 studies were assessed for risk of bias. Twelve studies had low, 2 moderate, 3 serious, and one high risk of bias. The latter study was excluded, resulting in 17 included studies. Five studies investigated a"stratified prehabilitation care" and 12 "non-stratified prehabilitation care". Stratified prehabilitation in 4 studies meant that the study sample was chosen considering a predefined intervention, and in the fifth study, the prehabilitation was stratified to individuals' needs. No direct comparison between the 2 approaches was possible. We found weak evidence for a positive effect of biopsychosocial prehabilitation compared to no prehabilitation on function (stratified studies) and pain neuroscience education prehabilitation compared to biomedical education on satisfaction (non-stratified studies) at 6 months post-TKA. We found strong evidence for positive effects of exercise prehabilitation compared to no prehabilitation on pain at 6 months and on function at 12 months post-TKA (non-stratified studies).

CONCLUSION

More research is needed of stratified prehabilitation care focusing on individual characteristics in people with KOA awaiting TKA.

REGISTRATION NUMBER

This systematic review was prospectively registered at PROSPERO on March 22, 2021 (no. CRD42021221098).

Is inpatient rehabilitation a predictor of a lower incidence of persistent knee pain 3-months following total knee replacement? A retrospective, observational study

Background

Moderate to severe levels of persistent knee pain have been estimated to affect up to 25% of people 3-months or more after a total knee replacement. It is unknown whether the type of rehabilitation pathway is associated with persistent high pain after surgery. Using a prospectively followed Australian cohort who underwent total knee replacement for knee osteoarthritis, this study aimed to i) report the incidence of high-intensity knee pain (defined as a score ≤ 15 on the Oxford Knee Score pain subscale) across time and ii) identify whether referral to inpatient rehabilitation was one of the predictors of persistent pain at 3-months post-surgery.

Methods

A retrospective analysis of a large prospective study was conducted using the Oxford Knee Score pain subscale to determine if participants had high pain at 3-months, 12-months and 36-months post-surgery. Relative risks for high pain at 3-, 12- and 36-months between the type of rehabilitation pathway were determined using Poisson multivariable regression with robust standard errors. The same technique was also employed to determine potential predictors, including rehabilitation pathway, of high pain at 3 months.

Results

The incidence of high pain in all participants was 73% pre-surgery and 10, 5 and 6% at 3-, 12- and 36-months respectively following knee replacement. There was a significant interaction between time and rehabilitation pathway, suggesting that the effect of the rehabilitation pathway varied across time. The incidence of high pain at 3-months did not significantly differ between those who attended inpatient rehabilitation (11.6%) and those discharged directly home (9.5%). Multivariable Poisson regression analysis identified the pre-surgical presence of high pain, co-morbid low back pain or other lower limb problem, younger age and having a major complication within 3-months following surgery as significant predictors of persistent pain whilst discharge to inpatient rehabilitation was not.

Conclusion

A small but clinically significant minority of people continued to have high pain levels at 3-, 12- and 36-months following a primary total knee replacement for osteoarthritis. Participation in an inpatient rehabilitation program does not appear to be an important predictor of ongoing knee pain.

Trial registration

The data were collected in the Evidence-based Processes and Outcomes of Care (EPOC) study, ClinicalTrials.gov Identifier: NCT01899443

Preoperative pain catastrophizing affects pain outcome after total knee arthroplasty

BACKGROUNDS

Preoperative widespread pain sensitization or pain catastrophizing could be associated with chronic pain after total knee arthroplasty (TKA). The aim of the present study was to examine the association between postoperative pain in patients undergoing TKA and preoperative factors, including patient characteristics and preoperative central sensitization as well as pain catastrophizing.

METHODS

Preoperative TKA patients were evaluated using the Central Sensitization Inventory (CSI)-9 and Pain Catastrophizing Scale (PCS). Postoperative knee pain was evaluated using a numerical rating scale (NRS) 6 months after TKA. Statistical analyses were performed to assess the relationship between NRS 6 months after TKA and preoperative factors, including patient characteristics, CSI-9, and PCS.

RESULTS

We enrolled 58 consecutive patients with osteoarthritis who underwent TKA. Using cutoff of 14, postoperative NRS was higher in the patients with ≥14 than the patients with <14 in CSI (p = 0.025). Postoperative NRS was higher in the patients with ≥30 than the patients with <30 in PCS (p = 0.043). Preoperative PCS was a significant risk factor of postoperative pain using a multivariate analysis.

CONCLUSIONS

Surgeon should recognize preoperative PCS could affect postoperative pain 6 months after TKA.

Pain catastrophizing and associated factors in preoperative total knee arthroplasty in Lanzhou, China: a cross-sectional study

Background

Pain catastrophizing in preoperative total knee arthroplasty (TKA) patients is associated with several poorly characterised factors in the literature. This study investigated the current state and associated factors of preoperative pain catastrophizing in patients undergoing TKA.

Methods

This descriptive cross-sectional study was conducted at the orthopedics ward of two tertiary hospitals in Lanzhou, China. Pain catastrophizing was measured using the Chinese versions of the Pain Catastrophizing Scale, Short Form-36 (physical function domain), Numerical Rating Scale, Oxford Knee Score, Hospital Anxiety and Depression Scale, and Life Orientation Test-Revised.

Results

The study included 360 participants. Preoperative TKA pain catastrophizing in all patients was high, with a mean score of 24.92 (SD: 12.38). The stepwise multiple linear regression analysis revealed anxiety (β = 0.548, P < 0.01), education level (β =  − 0.179, P < 0.01), physical function (β =  − 0.156, P < 0.01), and pain intensity during activity (β = 0.105, P = 0.015) as associated factors for pain catastrophizing, possibly explaining 51.2% of the total variation (F = 95.149, P < 0.01).

Conclusion

Anxiety was the most relevant factor for pain catastrophizing in patients with preoperative TKA. Lower education levels, poor physical function, and stronger pain intensity during the activity were also associated with pain catastrophizing.

Impact of pain sensitisation on the quality of life of patients with knee osteoarthritis

Objectives

We aim to evaluate the effect on different ways of classifying pain sensitisation on impact and quality of life (QoL) in knee osteoarthritis (KOA).

Methods

We used baseline data from a cohort of consecutive patients with KOA listed for arthroplasty. We collected demographics and number of painful body sites. We measured pressure pain thresholds at the right forearm (PPT_arm). Pain sensitisation was classified using: (1) widespread pain, (2) lowest 10th percentile of PPT_arm and (3) PainDETECT questionnaire ≥13/38. Impact and QoL were assessed using Western Ontario and McMaster Universities Osteoarthritis Index and Short Form-36. Impact and QoL scores in patients with or without pain sensitisation were compared. We evaluated the association of pain sensitisation measures with QoL scores using multivariable regression.

Results

233 patients (80% female, mean age 66 years) included in the analysis; 7.3%, 11.6% and 4.7% were classified as having pain sensitisation by widespread pain, low PPT_arm and PainDETECT criteria, respectively. There was minimal overlap of patients as classified as pain sensitisation phenotype by different measures. Patients with pain sensitisation had poorer QoL compared with those without. Low PPT_arm identified patients with poorer general health, while widespread pain and PainDETECT identified poorer QoL in more psychological domains. There was weak correlation between number of painful body sites and PainDETECT (rho=0.23, p<0.01), but no significant correlation with PPT_arm.

Conclusion

Patients with KOA with pain sensitisation have poorer QoL compared with those without, regardless of classification method. Different criteria defined patients with different pattern of QoL impact.

The Influence of Preoperative Mood and Treatment Expectations on Early Postsurgical Acute Pain After a Total Knee Replacement

BACKGROUND

Reducing postoperative pain immediately after surgery is crucial because severe postoperative pain reduces quality of life and increases the likelihood that patients develop chronic pain. Even though postoperative pain has been widely studied and there are national guidelines for pain management, the postoperative course is differently from one patient to the next. Different postoperative courses could be explained by factors related to the treatment context and the patients. Preoperative emotional states and treatment expectations are significant predictors of postoperative pain. However, the interaction between emotional states and preoperative treatment expectations and their effect on postoperative pain have not yet been studied. The aim of our study was to identify the interaction between emotional states, treatment expectation and early postsurgical acute pain.

METHODS

In this prospective clinical trial, we enrolled patients who had received a TKR at a German hospital between October 2015 and March 2019. Patients rated their preoperative pain on a numeric rating scale (NRS) 0-10 (0 = no pain and 10 = worst pain imaginable), their emotional states preoperatively on the Pain and State of Health Inventory (PHI), their preoperative treatment expectations on the Stanford Expectation of Treatment Scale (SETS), and their postoperative level of pain on a NRS 0-10.

FINDINGS

The questionnaires were completed by 122 patients (57% female). Emotional states predict negative treatment expectation F(6, 108) = 8.32, p < 0.001, with an excellent goodness-of-fit, R² = 0.31. Furthermore, a mediator analysis revealed that the indirect effects and therefore relationship between the emotional states sad (ab = 0.06, 95% CI[0.01, 0.14]), anxious (ab = 0.13, 95% CI[0.04, 0.22]), and irritable (ab = 0.09, 95% CI[0.03, 0.17]) and postoperative pain is fully mediated by negative treatment expectations. Whereas the emotional states tired (ab = 0.09, 95% CI[0.03, 0.17]), dizzy/numb (ab = 0.07, 95% CI[0.01, 0.20]), weak (ab = 0.08, 95% CI[0.03, 0.16] are partially mediated by negative treatment expectations.

CONCLUSION

The relationship between emotional states and postoperative pain is mediated by negative treatment expectations. Therefore, innovative treatment strategies to reduce postoperative pain should focus on eliminating negative treatment expectation through establishing a differentiated preoperative expectation management program that also focuses on emotional states.

Do Sex and Pain Characteristics Influence the Effectiveness of Pain Neuroscience Education in People Scheduled for Total Knee Arthroplasty? Secondary Analysis of a Randomized Controlled Trial

OBJECTIVE

This explorative study investigates the moderating effect of sex and baseline pain characteristics on the effectiveness of preoperative pain neuroscience education (PNE) plus knee joint mobilization versus biomedical education plus knee joint mobilization in patients who have knee osteoarthritis and are scheduled to undergo total knee arthroplasty (TKA).

METHODS

After baseline assessment of self-reported questionnaires (pain intensity, disability, symptoms of central sensitization and pain cognitions) and quantitative sensory testing, 44 participants with knee osteoarthritis were randomized into the PNE plus knee joint mobilization or biomedical education plus knee joint mobilization group. The questionnaires were retaken directly after and 1 month after 4 sessions of treatment and at 3 months after surgery. Based on baseline quantitative sensory testing results, the sample was subdivided into a high (showing high experimental pain levels and low pressure pain thresholds) and low pain cluster using principal components analysis and cluster analysis. Therapy effects over time were evaluated using 3-way analysis of variance, with time as the within factor and treatment, sex, and baseline pain cluster as between factors.

RESULTS

Women benefited significantly more from the PNE intervention compared with the control intervention in terms of self-reported symptoms of central sensitization. For both pain clusters, differences in therapeutic effects concerning pain intensity and pain cognitions were found, with higher superiority of the PNE intervention in the high-pain cluster subgroup compared with the low-pain cluster.

CONCLUSION

Based on these explorative analyses, it can be concluded that sex and preoperative pain measures may influence the effectiveness of preoperative PNE for some specific outcome measures in people scheduled to undergo TKA.

IMPACT

Although further research on this topic is needed, the potential influence of sex and preoperative pain measures on the effectiveness of preoperative PNE should be considered when implementing this intervention in people undergoing TKA.

Exploring the Pain in Patellofemoral Pain: A Systematic Review and Meta-Analysis Examining Signs of Central Sensitization

BACKGROUND

Patellofemoral pain (PFP) has high recurrence rates and minimal long-term treatment success. Central sensitization refers to dysfunctional pain modulation that occurs when nociceptive neurons become hyperresponsive. Researchers in this area of PFP have been increasingly productive in the past decade.

OBJECTIVE

To determine whether evidence supports manifestations of central sensitization in individuals with PFP.

DATA SOURCES

We searched MeSH terms for quantitative sensory testing (QST) pressure pain thresholds (PPTs), conditioned pain modulation (CPM), temporal summation, sensitization, hyperalgesia, and anterior knee pain or PFP in PubMed, SPORTDiscus, CINAHL, Academic Search Complete, and EBSCOhost.

STUDY SELECTION

Peer-reviewed studies that were written in English and published between 2005 and 2020 and investigated QST or pain mapping in a sample with PFP were included in this review.

DATA EXTRACTION

The initial search yielded 140 articles. After duplicates were removed, 78 abstracts were reviewed. The full text of 21 studies was examined, and we included 15 studies in our evaluation: 6 in the meta-analysis, 4 in the systematic review, and 5 in both the meta-analysis and systematic review.

DATA SYNTHESIS

A random-effects meta-analysis was conducted for 4 QST variables (local PPTs, remote PPTs, CPM, temporal summation). Strong evidence supported lower local and remote PPTs, impaired CPM, and facilitated temporal summation in individuals with PFP compared with pain-free individuals. Evidence for heat and cold pain thresholds was conflicting. Pain mapping demonstrated expanding pain patterns associated with long duration of PFP symptoms.

CONCLUSIONS

Signs of central sensitization were present in individuals with PFP, indicating altered pain modulation. The etiologic and treatment models of PFP should reflect the current body of evidence regarding central sensitization. Signs of central sensitization should be monitored clinically, and treatments with central effects should be considered as part of a multimodal plan of care.

Pain Neuroscience Education Delivered by a Student Physical Therapist for a Patient with Persistent Musculoskeletal Pain

Patient: Female, 65-year-old

Final Diagnosis: Fibromyalgia • neck pain radiculopathy • rotator cuff injury bilaterally

Symptoms: Chronic pain

Medication: —

Clinical Procedure: Manual therapy • pain neuroscience education

Specialty: Rehabilitation

Design and rationale of the ATtune Knee Outcome Study (ATKOS): multicenter prospective evaluation of a novel uncemented rotating platform knee system

Background

Total Knee Arthroplasty (TKA) remains the gold standard for treatment of debilitating symptoms of knee osteoarthritis (OA). Even though providing satisfactory results for the majority of patients, some studies report dissatisfaction after TKA to be as high as 20%. Among other things, pain catastrophising and self-efficacy are thought to compromise results of TKA. Implant manufacturers keep improving upon their designs in an attempt to improve functional outcomes. One of these novel knee systems is the Attune. To our knowledge, there are no clinical follow-up studies reporting results of the uncemented version. The main objective of this multicentre prospective observational study is to evaluate revision rate, complications, radiographic outcomes (i.e. alignment and radiolucent lines) and patient reported outcomes of the uncemented Attune mobile bearing TKA. Secondary objectives are (1) to assess physical function, return to sport and return to work after TKA and (2) to evaluate the long-term effect of preoperative psychological factors on satisfaction after TKA.

Methods

All patients presenting in the participating centres with knee pathology warranting joint replacement therapy will be considered for inclusion, an absolute indication for cemented fixation is the only exclusion criterium. Evaluation of clinical and radiographic performance (e.g. radiolucent lines) is done at 6 weeks, 6 months, 1 year, 5 years and 10 years after surgery using validated patient reported outcome measures. Cumulative revision rates are calculated after 5 and 10 years using Kaplan–Meier methods. Physical function is assessed with performance based measurements before and 1 year after surgery. Return to sports is assessed using the Tegner and University of California Los Angeles (UCLA) activity rating scale before and 1 year after surgery. Return to work is evaluated by inviting patients of working age to complete a short questionnaire 1 year after surgery. Psychologic factors are assessed using questionnaires for pain catastrophising, pain self-efficacy and mental health before, 5 years and 10 years after surgery. Preoperative psychologic scores are correlated to functional outcomes.

Discussion

The current study aims to report the clinical performance of a novel implant and can help provide insight in factors that play a role in satisfaction after TKA.

Trial registration

ClinicalTrials.gov identifier: NCT04247672 (January 30, 2020)

[Pain evolution in patients with central sensitization and osteoarthritis after knee arthroplasty]

INTRODUCTION

In patients with knee osteoarthritis, a group of 30% has been identified with central pain sensitization (CPS). The aim is to analyze the persistence of CPS in patients after knee arthroplasty and its correlation with pain intensity, functionality, determining factors and to evaluate physical examination as an assessment instrument.

MATERIAL AND METHODS

Quasi-experimental before-after study of patients operated on total knee arthroplasty. The evolution of subjective variables (pain characteristics, painDETECT questionnaire, WOMAC and Numerical Rating Scale) and physical examination (thermal hyperalgesia, allodynia, hypoesthesia, algometry and goniometry) 3 months before and 3 and 6 months after surgery are analysed using repeated measures ANOVA test for the quantitative ones and Cochran's Q for the qualitative ones. Spearmen test was used for the correlation of the questionnaires, the PD-Q and exploration variables and for the multivariate model of the PD-Q with clinical determinants.

RESULTS

Sixty-seven patients completed the study. The evolution of the quantitative and qualitative variables was significant, with a correlation between questionnaires. In the linear multivariate model of PD-Q, a significant relationship was obtained from personal history of flexion limitation, chronic musculoskeletal pain and the association between depression and time.

CONCLUSIONS

A significant percentage of patients with knee osteoarthritis after arthroplasty persisted with probable CPS, correlating with intensity and functionality. The limitation of mobility and previous chronic comorbidity could be determinants of CPS, with anamnesis and exploration being useful tools in consultation.

Early Identification of Patient Satisfaction Two Years After Total Knee Arthroplasty

BACKGROUND

There are numerous reports of poor satisfaction after total knee arthroplasty (TKA), yet there is little known about when to use evidence-based models of care to improve patient outcomes.

OBJECTIVE

This study aimed to characterize longitudinal changes in patient-reported satisfaction after TKA and to identify factors for early identification of poor satisfaction.

METHODS

For a cohort of primary TKA surgeries (n = 86), patient-reported outcomes were captured one week before TKA and 6 weeks, 12 weeks, 6 months, and 1 and 2 years after TKA. "Satisfied" versus "not fully satisfied" patients were defined using a binary response (≥90 vs <90) from a 100-point scale. Wilcoxon signed-rank tests identified changes in satisfaction between follow-up times, and longitudinal analyses examined demographic and questionnaire factors associated with satisfaction.

RESULTS

Improvements in satisfaction occurred within the first 6 months after TKA (P ≤ 0.01). Preoperative patient-reported outcome measures alone were not predictive of satisfaction. Key factors that improved longitudinal satisfaction included higher Oxford Knee Scores (odds ratio (OR) = 2.1, P < .001), general health (EQ-VAS, OR = 1.3, P = .03), and less visual analog scale pain (VAS; OR = 1.7, P < .001). Differences in these factors between satisfied and not fully satisfied patients were identified as early as 6 weeks after surgery.

CONCLUSION

Visibly different satisfaction profiles were captured among satisfied and not fully satisfied patient responses, with differences in patient-perceived joint function, general health, and pain severity occurring as early as 6 weeks after surgery. This study provides metrics to support early identification of patients at risk of poor TKA satisfaction, enabling clinicians to apply timely targeted treatment and support interventions, with the aim of improving patient outcomes.

Psychological Factors Associated with Functional Disability in Patients with Hip and Knee Osteoarthritis

Several studies have shown an association between psychosocial variables and functional capacity in chronic pain processes such as osteoarthritis. The aim of this study was to test a structural equations model that shows the predictive weight of certain variables such as catastrophizing, self-efficacy and kinesiophobia on functional pain and WOMAC subscales scores of pain and physical function of older patients diagnosed with hip and knee osteoarthritis. We also assessed the specific weight of age in terms of the factors. The study was conducted on a sample of 170 patients (142 women and 28 men mean age, 74.44 years range, 50-96 years). The main variables evaluated were WOMAC subscales scores of pain and physical function, self-efficacy, catastrophizing and kinesiophobia. To assess these variables, we used the Spanish validated version of the Western Ontario and McMaster Universities questionnaire, the Chronic Pain Self-Efficacy Scale, the Pain Catastrophizing Scale and the Tampa Scale for Kinesiophobia, respectively. We tested a structural equations model (IBM SPSS Amos version 22). The results showed the predominant predictive weight (both direct and indirect) of catastrophizing while simultaneously ruling out the relevance of age as a predictor of WOMAC subscales scores of pain and physical function. This study provides data of interest on the explanatory mechanisms that underlie the direct and inverse relationships between the studied psychological variables.

Strength training in addition to neuromuscular exercise and education in individuals with knee osteoarthritis-the effects on pain and sensitization

BACKGROUND

There is a lack of evidence of the relative effects of different exercise modes on pain sensitization and pain intensity in individuals with knee osteoarthritis (KOA).

METHODS

Ninety individuals with radiographic and symptomatic KOA, ineligible for knee replacement surgery, were randomized to 12 weeks of twice-weekly strength training in addition to neuromuscular exercise and education (ST+NEMEX-EDU) or neuromuscular exercise and education alone (NEMEX-EDU). Outcomes were bilateral, lower-leg, cuff pressure pain- and tolerance thresholds (PPT, PTT), temporal summation (TS), conditioned pain modulation (CPM), self-reported knee pain intensity and number of painful body sites.

RESULTS

After 12 weeks of exercise, we found significant differences in increases in PPT (-5.01 kPa (-8.29 to -1.73, p = .0028)) and PTT (-8.02 kPa (-12.22 to -3.82, p = .0002)) in the KOA leg in favour of ST+NEMEX-EDU. We found no difference in effects between groups on TS, CPM or number of painful body sites. In contrast, there were significantly greater pain-relieving effects on VAS mean knee pain during the last week (-8.4 mm (-16.2 to -0.5, p = .0364) and during function (-16.0 mm (-24.8 to -7.3, p = .0004)) in favour of NEMEX-EDU after 12 weeks of exercise.

CONCLUSION

Additional strength training reduced pain sensitization compared to neuromuscular exercise and education alone, but also attenuated the reduction in pain intensity compared to neuromuscular exercise and education alone. The study provides the first dose- and type-specific insight into the effects of a sustained exercise period on pain sensitization in KOA. Future studies are needed to elucidate the role of different exercise modes.

SIGNIFICANCE

This study is an important step towards better understanding the effects of exercise in pain management of chronic musculoskeletal conditions. We found that strength training in addition to neuromuscular exercise and education compared with neuromuscular exercise and education only had a differential impact on pain sensitization and pain intensity, but also that regardless of the exercise mode, the positive effects on pain sensitization and pain intensity were comparable to the effects of other therapeutic interventions for individuals with knee osteoarthritis.

Central sensitisation in chronic pain conditions: latest discoveries and their potential for precision medicine

Chronic pain is a leading cause of disability globally and associated with enormous health-care costs. The discrepancy between the extent of tissue damage and the magnitude of pain, disability, and associated symptoms represents a diagnostic challenge for rheumatology specialists. Central sensitisation, defined as an amplification of neural signalling within the CNS that elicits pain hypersensitivity, has been investigated as a reason for this discrepancy. Features of central sensitisation have been documented in various pain conditions common in rheumatology practice, including fibromyalgia, osteoarthritis, rheumatoid arthritis, Ehlers-Danlos syndrome, upper extremity tendinopathies, headache, and spinal pain. Within individual pain conditions, there is substantial variation among patients in terms of presence and magnitude of central sensitisation, stressing the importance of individual assessment. Central sensitisation predicts poor treatment outcomes in multiple patient populations. The available evidence supports various pharmacological and non-pharmacological strategies to reduce central sensitisation and to improve patient outcomes in several conditions commonly seen in rheumatology practice. These data open up new treatment perspectives, with the possibility for precision pain medicine treatment according to pain phenotyping as a logical next step. With this view, studies suggest the possibility of matching non-pharmacological approaches, or medications, or both to the central sensitisation pain phenotypes.

Central Sensitization Inventory is a useless instrument for detection of the impairment of the conditioned pain modulation in patients with chronic musculoskeletal pain

OBJECTIVE

The current study aimed to evaluate the concurrent validity and the diagnostic accuracy of the Central Sensitization Inventory (CSI) in detecting the impairment of the pain modulation in patients with chronic musculoskeletal pain.

METHODS

A cross-sectional study was conducted in 267 patients with chronic musculoskeletal pain enrolled consecutively in an outpatient department. The CSI (index method) were compared with the cold pressor test, which was the psychophysical test used to assess the conditioned pain modulation (CPM), (reference standard). Spearman's correlations assessed the concurrent validity, and measurements of the diagnostic accuracy were performed.

RESULTS

Ninety-three (34.8%) patients had CSI scores≥40. No significant correlation was found between CSI findings and the results of the CPT (dorsal forearm site or tibialis anterior site) was found. The cutoff point of 40 of the CSI showed values of sensitivity (35.1%, 95% CI: 22.6, 49.3) and specificity (65.2%, 95% CI: 58.4, 71.6) below 70%, and an accuracy of 59.1 (95% CI: 53.0, 65.1) when compared to the CPT to detect deficit. The ROC curve analysis yielded an area under the curve of 0.54 (95% CI: 0.45, 0.63, P>0.05).

CONCLUSIONS

The CSI is a useless instrument to detect the deficit in the CPM in patients with chronic musculoskeletal pain due to the absence of correlation with the psychophysical test result and the insufficient measurements of diagnostic accuracy.

Do patients with central sensitivity syndromes have poor subjective outcomes despite anatomical cure from pelvic organ prolapse surgery?

INTRODUCTION

Pelvic organ prolapse(POP) has an adverse impact on quality of life with lifetime risk of surgery varying from 11 to 20%. Conditions such as fibromyalgia (FMS), chronic fatigue syndrome (CFS/ME) and irritable bowel syndrome (IBS), collectively known as central sensitivity syndromes (CSS), may affect the outcome of POP surgery. The aim of this article is to compare the outcomes of vaginal POP surgery between women with and without CSS.

METHOD

This was a prospective cohort study. The validated Central Sensitisation Inventory (CSI) was used to identify women with CSS. Subjective and objective outcomes were compared between the two groups using POP-SS, Expectation and satisfaction/"EGGS", pain scores and the POP quantification system (POP-Q). A non-parametric test was used for analysis.

RESULT

Seventy-eight women were recruited. Complete data were available in 62 patients; 23 patients had evidence of CSS and 39 did not. Women with CSS had significantly higher pre- and post-operative POP-SS scores than those without (p < 0.0005, p = 0.004). Seventeen (73.9%) women with CSS compared to 38 (97.4%) women without CSS demonstrated improvement of a minimum 6 points on the POP-SS scale; however, this was not stastically significant. McGill's pain scores were higher in women with CSS both pre- and post-surgery. Ninety-five per cent of women without CSS achieved their goals and were satisfied with the surgery compared to 69.5% of women with CSS (p < 005).

CONCLUSION

There is a less favourable outcome of POP surgery in women with CSS compared to those without in terms of persistence of symptoms, pain and overall satisfaction.

Assessment of diagnostic criteria for the identification of central sensitization in patients with osteoarthritis pain: Results from a Delphi survey

To assess diagnostic criteria and currently used tools for the identification of central sensitization (CS) in patients with joint pain due to osteoarthritis (OA).Qualitative, cross-sectional and multicenter study based on a 2-round Delphi surveyPublic and private medical centers attending patients with joint pain.A total of 113 specialists in traumatology, physical medicine and rehabilitation, pain management, rheumatology, primary care physicians and geriatrics were enrolled in the study.Participants completed an ad-hoc 26-item questionnaire available from a microsite in Internet.The questionnaire was divided into 6 sections with general data on CS, impact of CS in patients with knee osteoarthritis (KOA), diagnostic criteria for CS, non-pharmacological and pharmacological treatment of CS and usefulness of the concept of CS in the integral management of patients with KOA. Consensus was defined as 75% agreement.Diagnostic criteria included pain of disproportionate intensity to the radiological joint lesion (agreement 86.7%), poor response to usual analgesics (85.8%), progression of pain outside the site of the lesion (76.1%) and concurrent anxiety and depression (76.1%). Based on the opinion of the specialists, about 61% of patients with KOA present moderate-to-severe pain, 50% of them show poor response to conventional analgesics, and 40% poor clinical-radiological correlation. Patients with KOA and CS showed higher functional disability and impairment of quality of life than those without CS (88.5%) and have a poor prognosis of medical, rehabilitation and surgical treatment (86.7%). Early diagnosis and treatment of CS may preserve function and quality of life during all steps of the disease (90.3%).The management of patients with osteoarthritis pain and CS requires the consideration of the intensity of pain related to the joint lesion, response to analgesics, progression of pain to other areas and concurrent anxiety and depression to establish an adequate therapeutic approach based on diagnostic criteria of CS.

Quantitative Sensory Testing Discriminates Central Sensitization Inventory Scores in Participants with Chronic Musculoskeletal Pain: An Exploratory Study

BACKGROUND

The Central Sensitization Inventory (CSI) is often used in clinical settings to screen for the presence of central sensitization. However, various cutoff scores have been reported for this tool, and scores have not been consistently associated with widespread pain sensitivity as measured with quantitative sensory testing (QST). The purpose of this study was to compare QST profiles among asymptomatic controls and participants with chronic musculoskeletal pain (CMP), and to determine the association between self-report questionnaires and QST in participants with CMP.

METHODS

Twenty asymptomatic controls and 46 participants with CMP completed the CSI, PROMIS-29, and QST assessments of mechanical and thermal pain thresholds remote to the area of pain. Receiver Operating Characteristic analysis revealed a cutoff score of 33.5 for the CSI. PROMIS-29 Quality of Life (QOL) inventory and QST measures were compared between low and high CSI groups.

RESULTS

The high CSI group (n = 19) had significantly lower mechanical and thermal pain thresholds, and larger impairments in QOL measures, compared to the low CSI group (n = 27) and asymptomatic controls. Participants with CSI scores < 33.5 presented similarly to asymptomatic controls. Anxiety, pain interference, and CSI scores demonstrated the highest number of significant associations to QST measures.

CONCLUSION

A cutoff score of 33.5 on the CSI may be useful for discriminating widespread pain sensitivity and quality of life impairments in participants with CMP. Future studies should consider how the presence of high or low CSI may impact differential diagnosis, prognosis, and treatment responsiveness for patients with primary or secondary CMP.

Physical activity and cold pain tolerance in the general population

BACKGROUND

The relationship between habitual physical activity (PA) and experimental pain tolerance has been investigated in small samples of young, healthy and/or single-sex volunteers. We used a large, population-based sample to assess this relationship in men and women with and without chronic pain.

METHODS

We used data from the sixth and seventh Tromsø Study surveys (2007-2008; 2015-2016), with assessed pain tolerance of participants with the cold pressor test (CPT: dominant hand in circulating cold water at 3°C, maximum test time 106 s), and self-reported total amount of habitual PA in leisure time (n = 19,087), exercise frequency (n = 19,388), exercise intensity (n = 18,393) and exercise duration (n = 18,343). A sub-sample had PA measured by accelerometers (n = 4,922). We used Cox regression to compare CPT tolerance times between self-reported PA levels. For accelerometer-measured PA, we estimated hazard ratios for average daily activity counts, and for average daily minutes of moderate-to-vigorous PA done in bouts lasting 10 min or more. Models were tested for PA-sex, and PA-chronic pain and PA-moderate-to-severe chronic pain interactions.

RESULTS

Leisure-time PA, exercise intensity and exercise duration were positively associated with CPT tolerance (p < .001; p = .011; p < .001). More PA was associated with higher CPT tolerance. At high levels of leisure-time PA and exercise intensity, men had a significantly higher CPT tolerance than women. Accelerometer-measured PA was not associated with CPT tolerance.

CONCLUSIONS

This study is one of the first to show that higher self-reported habitual PA was connected to higher experimental pain tolerance in a population-based sample, especially for men. This was not found for accelerometer-measured PA.

SIGNIFICANCE

This study finds that higher level of self-reported leisure-time physical activity is associated with increased cold pressor pain tolerance in a large population-based sample. Though present in both sexes, the association is strongest among men. Despite the robust dose-response relationship between pain tolerance and self-reported activity level, no such relationship was found for accelerometer-measured activity, reflecting a possible discrepancy in the aspect of physical activity measured. Though the study design does not permit causal conclusions, the findings suggest that increasing physical activity may increase pain tolerance in the general population.

Does preoperative neuropathic-like pain and central sensitisation affect the post-operative outcome of knee joint replacement for osteoarthritis? A systematic review and meta analysis

BACKGROUND

Almost a third of those undergoing knee replacement for osteoarthritis have poor outcomes despite technically successful surgery. Preoperative neuropathic-like pain and/or pain sensitisation may increase the risk of pain following joint replacement.

OBJECTIVE

To examine whether preoperative neuropathic-like pain and pain sensitisation predicts pain, function and satisfaction following joint replacement for knee osteoarthritis.

DESIGN

Systematic review with meta-analysis.

METHODS

Medline, EMBASE and CINAHL were systematically searched until March 2020. Studies detecting neuropathic-like pain and/or sensitisation using self-report questionnaires prior to knee replacement for osteoarthritis, and relating this to post-operative outcomes were identified. Data extraction, risk of bias assessment and meta-analysis were performed, where appropriate.

RESULTS

Five manuscripts, including one preprint, examining six cohorts were included: four used painDETECT or modified painDETECT, one the Self-Report Leeds Assessment of Neuropathic Symptoms and Signs, and another the Central Sensitisation Inventory to identify preoperative characteristics. Three studies showed preoperative neuropathic-like pain or sensitisation was associated with more intense post-operative pain. All four studies examining the risk of significant pain after knee replacement suggested it was increased after >3 months. The only study examining patient satisfaction and function found reduced satisfaction, but no difference in function in those with preoperative sensitisation. Meta-analysis found the relative risk of increased pain following knee replacement in those with neuropathic-like pain (painDETECT ≥13) to be 2.05 (95% confidence intervals 1.51, 2.79).

CONCLUSION

These results provide consistent but limited evidence that self-report tools detecting neuropathic-like pain and/or pain sensitisation, predict patients at higher risk of pain following knee replacement.

Preoperative pain neuroscience education for shoulder surgery: A case series

Background

Central sensitisation, in addition to high levels of fear-avoidance and pain catastrophisation may exist in a subgroup of patients with shoulder pain. Pain neuroscience education (PNE) has been shown to positively influence sensitivity of the nervous system, as well as reduce fear and catastrophisation prior to lumbar and total knee surgery. To date, no study has examined the application of PNE prior to shoulder surgery.

Objectives

This study examined the response to preoperative PNE in patients preparing for shoulder surgery.

Method

An exploratory pre–post case series was conducted. Twelve patients scheduled for surgery completed various pre-education measurements including shoulder pain, fear-avoidance, pain catastrophisation, beliefs and expectations regarding surgery, active shoulder flexion and pressure pain thresholds for the involved and uninvolved shoulder and the dominant-sided knee. Patients underwent a standard 30-min, one-on-one PNE session with a physiotherapist prior to surgery.

Results

Following education, all measures improved with some failing to reach significance: self-reported pain (p = 0.125), pain catastrophisation (p = 0.250) and pain pressure threshold of the uninvolved shoulder (p = 0.68) and knee (p = 0.097). Fear-avoidance (p = 0.013), active shoulder flexion (p = 0.013) and pain pressure threshold for the involved shoulder (p = 0.004) significantly improved.

Conclusion

A small patient group improved beyond minimal detectable change and/or minimal clinical important difference after education. No significant shifts of the preoperative beliefs occurred after education.

Clinical implications

Preoperative PNE may be beneficial to a subgroup of patients scheduled for shoulder surgery.

Stability of Measures of Pain Catastrophizing and Widespread Pain Following Total Knee Replacement

OBJECTIVE

Pain catastrophizing and widespread pain are predictors of pain chronicity/severity. Gaps remain in our understanding of the extent to which each is a stable (trait) or dynamic (state) variable. We undertook this study to assess the stability of each variable from before to after total knee replacement (TKR) and whether changes are explained by pain improvements.

METHODS

We used data from a prospective study of TKR recipients ages ≥40 years. Questionnaires included body pain diagrams assessing widespread pain, the Pain Catastrophizing Scale (PCS), and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale. We divided subjects into widespread pain groups (0 versus 1-2 versus ≥3 pain regions) and into low and high PCS score groups (<16 versus ≥16). We assessed changes in group membership from pre-TKR to 12 months post-TKR, then compared these changes between subjects with most and least WOMAC pain improvement.

RESULTS

A total of 176 subjects completed scales at both time points; 64% were female, the mean age was 66 years, and baseline median WOMAC pain score was 40. In all, 71% of subjects in the high PCS score group improved to join the low PCS score group at follow-up. While 73 subjects (41%) changed widespread pain group, they were similarly likely to worsen and to improve. We found a statistically significant positive association of improvement in WOMAC pain score with improvement in PCS score (r = 0.31), but not widespread pain (r = -0.004).

CONCLUSION

The PCS score reflects state-like aspects of catastrophizing that diminish along with pain. In contrast, widespread pain scores worsened and improved equally often, regardless of knee pain relief. The findings urge caution in interpreting PCS score and widespread pain as trait measures in musculoskeletal research.

Measurement properties of Pain Catastrophizing Scale in patients with knee osteoarthritis

OBJECTIVES

Pain catastrophizing impacts symptoms and outcomes for knee osteoarthritis (OA). We evaluated the internal consistency, content, construct and structure validity of the Pain Catastrophizing Scale (PCS) in patients with knee OA.

METHODS

We evaluated content validity of PCS via cognitive interviews. We then recruited patients with knee OA enlisted for knee replacement (KR) surgery in a Singapore tertiary referral hospital for cross-sectional validation evaluation of PCS. Data was collected 2 weeks prior to KR. Analyses was guided by the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) framework for internal consistency, construct validity and structure validity.

RESULTS

Adequate content validity was confirmed from 10 patients in cognitive interviews. 675 (70.4% female, mean (standard deviation, SD) age = 65.52 (6.84) years) were included (91.7% total KR, 8.3% unicompartmental KR) in the cross-sectional study. The mean (SD) PCS score was 12.65 (10.55), with 0.14% and 8.63% ceiling and floor effects, respectively. PCS demonstrates high internal consistency (Cronbach's alpha = 0.94). Construct validity was demonstrated by fulfilment of seven out of seven (100%) a priori hypotheses. PCS was strongly correlated with anxiety and depression, and moderately correlated with physical functioning and mental health domains of the short form 36 health survey (SF-36). Sensitivity analyses between Chinese and non-Chinese subgroups are generally consistent. From confirmatory factor analysis, the PCS model showed good fit for a second-order, three-factor structure (CFI = 0.965, TLI = 0.950, SRMR = 0.031).

CONCLUSIONS

This study supports internal consistency, construct validity and structural validity of PCS as a measure of pain catastrophizing in knee OA patients. Key points • The PCS is validated for measuring pain catastrophizing in knee OA patients, for evaluation of possible link to post-KR surgery satisfaction outcomes and other purposes.

Predictors of Pain, Function, and Change in Patellofemoral Pain

BACKGROUND

Identification of factors predictive of outcome and change is important to improve treatment for patellofemoral pain (PFP). Few studies have examined the predictive value of psychological factors in PFP, although they have been reported to be important predictors in other musculoskeletal pain conditions.

PURPOSE

To evaluate predictors of pain, function, and change 1 year after an exercise-based intervention in PFP.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

In sum, 112 patients were recruited to a randomized controlled trial; 98 attended 1-year follow-up. There were no between-group differences in the trial; thus, the material was analyzed as 1 cohort. Nine baseline factors-sex, bilateral pain, worst pain, pain duration, Anterior Knee Pain Scale (AKPS), kinesiophobia, anxiety and depression, self-efficacy, and number of pain sites throughout the body-were investigated for their predictive ability on outcome at 1 year (AKPS, worst pain) and for change at 1 year (global change score, change in AKPS, and change in worst pain). Multivariable linear regression models with stepwise backward removal method were used to find predictors of poor outcome.

RESULTS

Number of pain sites at baseline was a significant predictor of worse outcome for AKPS (B = -2.7; 95% CI, -4.0 to -1.3; P < .01), worst pain (B = 0.5; 95% CI, 0.2-0.8; P < .01), global change (B = -0.8; 95% CI, -1.2 to -0.5; P < .01), change in AKPS (B = -2.7; 95% CI, -4.0 to -1.3; P < .01), and change in worst pain (B = 0.5, 95% CI, 0.2-0.8; P < .01) at 1 year. Baseline scores for AKPS and worst pain predicted respective 1-year levels and change scores (P < .01). Lower self-efficacy and male sex predicted less global change (P < .01). Longer pain duration predicted final score and change score for worst pain (P < .01). The predictive models had reasonable fit with adjusted R² from 0.22 to 0.35.

CONCLUSION

Higher number of pain sites throughout the body was a consistent predictor of poor outcome and less change at 1 year. Baseline levels for AKPS and worst pain predicted respective final scores and change scores.

REGISTRATION

NCT02114294 ( ClinicalTrials.gov identifier).

Prognostics for pain in osteoarthritis: Do clinical measures predict pain after total joint replacement?

A significant proportion of osteoarthritis (OA) patients continue to experience moderate to severe pain after total joint replacement (TJR). Preoperative factors related to pain persistence are mainly studied using individual predictor variables and distinct pain outcomes, thus leading to a lack of consensus regarding the influence of preoperative parameters on post-TJR pain. In this prospective observational study, we evaluated knee and hip OA patients before, 3 and 6 months post-TJR searching for clinical predictors of pain persistence. We assessed multiple measures of quality, mood, affect, health and quality of life, together with radiographic evaluation and performance-based tasks, modeling four distinct pain outcomes. Multivariate regression models and network analysis were applied to pain related biopsychosocial measures and their changes with surgery. A total of 106 patients completed the study. Pre-surgical pain levels were not related to post-surgical residual pain. Although distinct pain scales were associated with different aspects of post-surgical pain, multi-factorial models did not reliably predict post-surgical pain in knee OA (across four distinct pain scales) and did not generalize to hip OA. However, network analysis showed significant changes in biopsychosocial-defined OA personality post-surgery, in both groups. Our results show that although tested clinical and biopsychosocial variables reorganize after TJR in OA, their presurgical values are not predictive of post-surgery pain. Derivation of prognostic markers for pain persistence after TJR will require more comprehensive understanding of underlying mechanisms.

Less Severe Preoperative Synovitis is Associated With Higher Self-reported Pain Intensity 12 Months After Total Knee Arthroplasty-An Exploratory Prospective Observational Study

OBJECTIVES

Synovitis is one of the possible pain generators in osteoarthritis (OA) and is associated with upregulation of proinflammatory cytokines, which can lead to worsening of the postoperative pain. This exploratory study aimed to investigate the association between perioperative synovitis and self-reported pain 12 months after total knee arthroplasty (TKA) in patients with OA.

MATERIALS AND METHODS

Twenty-six knee OA patients were included in this analysis. The perioperative volume of synovitis in predefined locations was assessed by contrast-enhanced magnetic resonance imaging (CE-MRI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Perioperative synovitis was assessed histologically from biopsies of the synovium. Highest pain intensity within the last 24 hours (Visual Analog Scale, VAS, 0 to 100) was assessed before and 12 months after TKA. Patients were divided into a low-pain intensity (VAS≤30) and a high-pain intensity (VAS>30) group on the basis of 12 months postoperative VAS.

RESULTS

The high-pain intensity group had significantly lower perioperative contrast-enhanced-synovitis (P=0.025), DCE-synovitis (P<0.04), and a trend toward lower histologically assessed synovitis (P=0.077) compared with the low-pain intensity group. Perioperative synovitis scores were inversely correlated with pain intensity 12 months after TKA (P<0.05), indicating that more severe perioperative synovitis is associated with less severe pain intensity at 12 months.

DISCUSSION

Higher degrees of perioperative synovitis scores are found to be associated with less postoperative pain 12 months after TKA. Further, correlation analysis revealed that less severe perioperative CE-MRI and DCE-MRI synovitis was associated with higher pain intensity 12 months after TKA, suggesting that CE-MRI and DCE-MRI synovitis grades could be used as imaging markers for prediction of chronic postoperative pain after TKA.

Effectiveness and reporting standards of psychological interventions for improving short-term and long-term pain outcomes after total knee replacement: a systematic review

OBJECTIVES

To assess the effectiveness and reporting standards of psychological interventions for improving outcomes after total knee replacement (TKR).

DESIGN

Medline, Embase, and PsycINFO were searched from inception to up to 9 May 2019 with no language restrictions applied. Randomised controlled trials (RCTs) assessing the effectiveness of psychological interventions for short-term and long-term postoperative pain after TKR were included. Screening, data extraction, and assessment of methodological quality were performed in duplicate by two reviewers. The primary effectiveness outcome was postoperative pain severity and the primary harm outcome was serious adverse events. Secondary outcomes included function, quality of life, and psychological well-being. Reporting standards were assessed using the Template for Intervention Description and Replication (TIDieR) checklist for intervention reporting.

RESULTS

12 RCTs were included, with a total of 1299 participants. Psychological interventions comprised music therapy (five studies), guided imagery and music (one study), hypnosis (one study), progressive muscle relaxation with biofeedback (one study), pain coping skills programme (one study), cognitive-behavioural therapy (two studies), and a postoperative management programme (one study). Due to the high heterogeneity of interventions and poor reporting of harms data, it was not possible to make any definitive statements about the overall effectiveness or safety of psychology interventions for pain outcomes after TKR.

CONCLUSION

Further evidence about the effectiveness of psychological interventions for improving pain outcomes after TKR is needed. The reporting of harm outcomes and intervention fidelity is currently poor and could be improved. Future work exploring the impact of intervention timing on effectiveness and whether different psychological approaches are needed to address acute postoperative pain and chronic postoperative pain would be of benefit.

PROSPERO REGISTRATION NUMBER

CRD42018095100.

Persistence of pain in humans and other mammals

Evolutionary models of chronic pain are relatively undeveloped, but mainly concern dysregulation of an efficient acute defence, or false alarm. Here, a third possibility, mismatch with the modern environment, is examined. In ancestral human and free-living animal environments, survival needs urge a return to activity during recovery, despite pain, but modern environments allow humans and domesticated animals prolonged inactivity after injury. This review uses the research literature to compare humans and other mammals, who share pain neurophysiology, on risk factors for pain persistence, behaviours associated with pain, and responses of conspecifics to behaviours. The mammal populations studied are mainly laboratory rodents in pain research, and farm and companion animals in veterinary research, with observations of captive and free-living primates. Beyond farm animals and rodent models, there is virtually no evidence of chronic pain in other mammals. Since evidence is sparse, it is hard to conclude that it does not occur, but its apparent absence is compatible with the mismatch hypothesis. This article is part of the Theo Murphy meeting issue 'Evolution of mechanisms and behaviour important for pain'.

Identification of Functioning Domains in the Presurgical Period and Their Relationships with Opioid Use and Pain Catastrophizing

OBJECTIVES

The National Institutes of Health Patient-Reported Outcomes Measurement Information System (PROMIS) is a multidimensional screening system evaluating biopsychosocial factors affecting pain and functioning. Using a military sample, the current study 1) examined the structure and domains of the PROMIS, the Defense and Veterans Pain Rating Scale 2.0 (DVPRS), and the Pain Catastrophizing Scale (PCS) within a presurgical setting and 2) examined the relationship of these variables to pre- and postsurgical opioid use.

METHODS

This cross-sectional study included 279 adult patients scheduled for surgery at the Walter Reed National Military Medical Center and a validation sample of 79 additional patients from the Naval Medical Center, San Diego. PROMIS, DVPRS, PCS, and opioid use data were collected before surgery. Exploratory factor analysis and confirmatory factor analysis identified the latent structure for the measures. A structural equation model (SEM) examined their relationship to pre- and postsurgical opioid use.

RESULTS

Two latent factors represented Psychosocial Functioning (PROMIS Depression, PROMIS Anxiety, and PROMIS Social Isolation) and Pain Impact (DVPRS, PROMIS Pain Interference, PROMIS Physical Functioning). The remaining PROMIS scales did not load onto a single factor. In the SEM, the two latent factors and PCS were significantly related to pre- and postsurgical opioid use.

CONCLUSIONS

This study highlights the utility and relative ease of using a convenient multidimensional assessment in presurgical settings. Using such an assessment can help provide targeted interventions for individuals who may be at greatest risk for negative postsurgical outcomes.

Hip and knee kinematics of the forward lunge one year after unicondylar and total knee arthroplasty

Patients with unicondylar knee arthroplasty (UKA) report higher functionality compared to those with total knee arthroplasty (TKA). However, these patients should also be assessed during more demanding tasks in order to appreciate their true functionality. The forward lunge (FL) is a motor task commonly used in clinics to evaluate functional recovery after knee replacement surgery. Unfortunately, clear evidence comparing FL kinematics between patients with UKA and TKA is still missing. The purpose of this study was to compare hip and knee joint kinematics during the FL between patients with UKA, TKA and controls. Twenty subjects (8 TKA, 6 UKA, 6 controls) underwent 3D motion analysis during a FL. Differences in hip and knee kinematics between groups were identified using statistical parametric mapping. We concluded that patients with TKA demonstrated reduced knee and hip flexion angles during the loaded phase of the FL, which could have been an attempt to unload the knee joint. This is in contrast to patients with UKA, who showed similar knee and hip joint kinematics compared to controls throughout the entire FL. It seems that retaining the cruciate ligaments is beneficial for the execution of a complex motor task such as the FL.

Preoperative Radiographic Osteoarthritis Severity Modifies the Effect of Preoperative Pain on Pain/Function After Total Knee Arthroplasty: Results at 1 and 2 Years Postoperatively

BACKGROUND

Osteoarthritis (OA) severity as demonstrated by preoperative radiographs and preoperative pain play an important role in the indication for total knee arthroplasty (TKA). We investigated whether preoperative radiographic evidence of OA severity modified the effect of preoperative self-reported pain on postoperative pain and function 1 and 2 years after TKA for OA.

METHODS

Data from the Longitudinal Leiden Orthopaedics Outcomes of Osteoarthritis Study (LOAS), a multicenter cohort study on outcomes after TKA, were used. OA severity was assessed radiographically with the Kellgren and Lawrence (KL) score (range, 0 to 4). Pain and function were evaluated with the Knee injury and Osteoarthritis Outcome Score (KOOS). After adjustment for body mass index (BMI), age, sex, and the Mental Component Summary scores from the Short Form-12, multivariate linear regression analyses with an interaction term between the preoperative KL score and preoperative pain were performed.

RESULTS

The study included 559 patients. The preoperative KL score was independently associated with 1-year postoperative pain and function (β = 5.4, 95% confidence interval [CI] = 1.4 to 9.4, and β = 7.7, 95% CI = 3.2 to 12.2), while preoperative pain was associated only with postoperative pain (β = 0.3, 95% CI = 0.1 to 0.6) and not with postoperative function (β = 0.2, 95% CI = -0.2 to 0.5). Comparable associations were found between 2-year postoperative pain and KL score (β = 8.0, 95% CI = 3.2 to 12.7) and preoperative pain (β = 0.5, 95% CI = 0.1 to 0.8) and between 2-year postoperative function and KL score (β = 7.7, 95% CI = 3.2 to 12.2). The study showed a trend toward the KL score modifying the effect of preoperative pain on 1-year postoperative pain (β = -0.1, 95% CI = -0.1 to 0.0) and 2-year postoperative pain (β = -0.1, 95% CI = -0.2 to 0.0) and on 1 and 2-year function (β = -0.1, 95% CI = -0.2 to 0.0 for both), with the effect of preoperative pain on postoperative pain and function seeming to become less important when there was radiographic evidence of greater preoperative OA severity.

CONCLUSIONS

Patients with less pain and higher KL grades preoperatively had better function and pain outcomes 1 and 2 years after TKA. However, the effect of preoperative pain on the postoperative outcomes seems to become less important when the patient has radiographic evidence of more severe OA. We believe that analysis of the severity of preoperative pain is an important proxy for optimal postoperative patient outcome.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

The influence of pre- and perioperative administration of gabapentin on pain 3-4 years after total knee arthroplasty

BACKGROUND AND AIMS

Approximately 20% of patients having total knee arthroplasty (TKA) will experience chronic postoperative pain. Recently, preoperative pain facilitation has been associated with chronic pain after TKA, and gabapentin has been shown to decrease pain facilitation. The current study is a secondary follow-up of a primary RCT investigating the effect of gabapentin on acute postoperative pain after TKA and exploring the effect of pre- and perioperative administration of gabapentin on chronic postoperative pain and psychological state 3-4 years after TKA.

METHODS

Patients scheduled for TKA were randomized to either gabapentin 1,300 mg/day, gabapentin 900 mg/day, or placebo daily from 2-h before and 6 days after operation. Pre- and 3-4 years postoperatively pain scores related to pain while walking, at rest, when flexing the hip or the knee were collected. At the same time, the pain catastrophizing scale (PCS) and hospital anxiety and depression scale subscales for anxiety (HADS-A) and depression (HADS-D) were collected.

RESULTS

Lower postoperative pain while walking, flexing the hip, and at rest were found compared with preoperative scores (p<0.03), but these were not associated with gabapentin treatment (p>0.19). Significantly lower postoperative PCS and HADS-A scores were seen compared with preoperative scores (p<0.001), but these were not associated with gabapentin treatment (p>0.55).

CONCLUSIONS

The current study found that pre- and perioperative administrations of gabapentin do not influence the pain or psychological state 3-4 years after TKA.

IMPLICATIONS

The current study does not support that short-term pre- and perioperative use of gabapentin can reduce the development of chronic postoperative pain after TKA.

Pain: Persistent postsurgery and bone cancer-related pain

The generation of neuropathic pain is a complex dynamic process. Factors involved include one or more dysregulated sensory neural pathways; dysregulated activity of specific neurotransmitters, synapses, receptors and cognitive and emotional neural circuits; and the balance between degenerative and regenerative neural events. Risk factors include age, sex, cognition, emotions, genetic polymorphism, previous or ongoing chronic pain conditions and the use of certain drugs. Intense pain experienced before, during and after surgery is a risk factor for the development of central sensitization with consequent persistent postsurgery neuropathic pain. Blockade of N-methyl-D-aspartate receptors with appropriate drugs during and immediately after surgery may prevent persistent postsurgical pain. Most cancers, but particularly malignant metastases in bone, can induce persistent pain. Local factors including direct damage to sensory nerve fibres, infiltration of nerve roots by cancer cells and algogenic biological agents within the microenvironment of the tumour bring about central sensitization of dorsal horn neurons, characterized by neurochemical reorganization with persistent cancer pain. In this article, the clinical features, pathogenesis and principles of management of persistent postsurgery pain and cancer pain are briefly discussed.