Association of exercise therapy and reduction of pain sensitivity in patients with knee osteoarthritis: a randomized controlled trial

Efficacy of Mulligan joint mobilizations and trunk stabilization exercises versus isometric knee strengthening in the management of knee osteoarthritis: a randomized controlled trial

BACKGROUND

Knee osteoarthritis (KOA) progression is often influenced by biomechanical factors. Biomechanical interventions, such as Trunk stabilization exercise (TSE) and Mulligan joint mobilization (MWM), may offer relief from KOA symptoms and potentially slow disease progression. However, the comparative efficacy of these therapies remains uncertain. This study aimed to compare the efficacy of TSE, Mulligan joint mobilization, and isometric knee strengthening (KSE) on disability, pain severity, and aerobic exercise capacity in patients with KOA.

METHODOLOGY

A randomized controlled trial (RCT) with three intervention groups was conducted between September 2020 to February 2021. The study enrolled adults aged between 40 and 60 years with a confirmed KOA diagnosis recruited from the physical therapy clinic of the Sindh Institute of Physical Medicine and Rehabilitation, Pakistan. Participants were randomly assigned to receive 24 sessions of either TSE, MWM, or KSE. The knee's functionality was assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS), pain on a visual analogue scale (VAS), and two objective functional tests-the 6-minute walk test (6MWT) and the 11-stair climb test (SCT). These assessments were conducted at baseline, the third week, and the sixth week. Changes in outcome measures were analyzed using a mixed-design ANOVA with Bonferroni post-hoc analysis, with statistical significance set at a p-value < 0.05.

RESULT

Of the 60 participants, 22 (36.7%) were females, and 38 (63.3%) were males. Within-group analysis revealed a significant improvement in all outcome measures at the third week (p < 0.05) and sixth week (p < 0.05). Notably, the TSE group exhibited a greater reduction in mean difference (M.D) in VAS scores than the MWM and KSE groups across various measures in the third week. At rest, during stair ascent, and descent, the TSE group showed significant improvements in VAS scores: MWM (-2.05; -1.94; -1.94), TSE (-2.38; -2.5; -2.5), KSE (-1.05; -0.63; -0.63). Additionally, during sub-maximal exercise capacity assessment, the TSE group showed greater improvement (MWM 12.89; TSE 22.68; KSE 7.89), as well as in Knee Injury and Osteoarthritis Outcome Score for activities of daily living (KOOS-ADL) (MWM 20.84; TSE 28.84; KSE 12.68), and KOOS-pain (MWM 24.84; TSE 27.77; KSE 5.77) at the third-week assessment (p < 0.05). The TSE group demonstrated significant improvements (p < 0.05) across various measures in the sixth week. Specifically, improvements were observed in VAS scores at rest (MWM - 4.15; TSE - 4.42; KSE - 3.78), during stair ascent (MWM - 3.89; TSE - 4.88; KSE - 3.56) and descent (MWM - 3.78; TSE - 4.05; KSE - 2.94). Furthermore, significant improvements were noted in the stair climb test (MWM - 7.05; TSE - 7.16; KSE - 4.21), 6-minute walk test (6MWT) (MWM 22.42; TSE 37.6; KSE 13.84), KOOS-pain (MWM 41.47; TSE 49.11; KSE 28.73), and KOOS-ADL (MWM 40.31; TSE 50.57; KSE 26.05).

CONCLUSION

In this study in patients with KOA, TSE had greater efficacy compared to MWM and KSE in enhancing functional levels, reducing pain, improving sub-maximal exercise capacity, and performance on the stair climb test. Importantly, mean scores between the groups, particularly in the TSE group, reached the minimally important level, particularly in key areas such as pain, functional levels, sub-maximal exercise capacity, and stair climb performance. Clinicians should consider the significant pain reduction, improved functionality, and enhanced exercise capacity demonstrated by TSE, indicating its potential as a valuable therapeutic choice for individuals with KOA.

TRIAL NO

ClinicalTrials.gov = NCT04099017 23/9/2019.

The effect of balance exercises on central sensitization in patients with knee osteoarthritis

The aim of this study was to evaluate the effectiveness of balance exercises on functional status, pain, balance, and central sensitization in patients with knee osteoarthritis (OA). Patients diagnosed with bilateral Kellgren-Lawrence grade ≥ 2 primary knee OA and associated central sensitization were included in the study. Patients were randomized into two groups. Both groups were provided with verbal and written information on knee OA. In addition, the intervention group received a supervised balance exercise program for 6 weeks, 3 days a week on alternating days. The outcome measures were the changes in the Central Sensitization Inventory (CSI), Visual Analog Scale (VAS) pain, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Berg Balance Scale, and Y Balance Test. Evaluations were performed at baseline, immediately after treatment (6th week) and at 12th week. The study included 40 patients, 20 patients in each group. At the end of the treatment period (6th week), the improvement in CSI score, WOMAC pain, WOMAC physical function, WOMAC total score, Y Balance Test scores, and VAS pain during activity was significantly greater in the intervention group than that in the control group (p < 0.001). Regarding the changes from baseline to the 12th week, the intervention group experienced greater improvement in most of the outcome measures. Yet, the change in WOMAC pain score, Berg Balance Scale score, and VAS pain at rest was similar between the study groups (p = 0.05, p = 0.257, and p = 0.385, respectively). A two-model multiple linear regression analysis revealed that the changes in VAS pain (during activity) after the treatment and at follow-up [(p = 0.004, adjusted R2: 0.346) and (p = 0.002, adjusted R2: 0.391), respectively], as well as changes in WOMAC pain from baseline to follow-up (p = 0.020, ΔR2 = 0.245) significantly affected central sensitization. However, changes in Y Balance Test and WOMAC total scores did not appear to have a significant impact on the improvement in central sensitization (p > 0.05). Balance exercises may provide improvement in central sensitization, functional status, and dynamic balance among patients with knee OA. The improvement in central sensitization depends mostly on the pain relief effect of balance exercises.

High-Intensity Progressive Rehabilitation Versus Routine Rehabilitation After Total Knee Arthroplasty: A Randomized Controlled Trial

BACKGROUND

This study aimed to compare the effectiveness of high-intensity progressive rehabilitation training with routine training in the early treatment of patients undergoing total knee arthroplasty.

METHODS

There were 78 patients who underwent total knee arthroplasty and were randomized into high-intensity progressive training and routine rehabilitation training groups (RRT). The primary outcome measures were the American Hospital for Special Surgery Knee Score (HSS), with secondary outcomes including patient satisfaction, visual analog pain score, first time of standing after surgery, 6-minute walk test, 36-Item Short Form Survey (SF-36), and length of hospital stay. The incidence of postoperative complications were recorded.

RESULTS

The HSS scores were higher in the intervention group at 2 weeks, 3 months, and 12 months postoperatively (P < .001). The RRT group had higher visual analog pain scores than the intervention group at 24 hours, 3 days, and 2 weeks after surgery (P < .001). The intervention group had an earlier the first time of standing after surgery and a longer 6-minute walk test distance (P < .001, P = .028, P < .001, P < .001). Patient satisfaction was higher in the intervention group, with a higher quality of life rating at 3 months postoperatively (P < .001). However, 1 year after surgery, the 2 groups had no significant differences in mental component summaries. The length of hospital stay was shorter in the intervention group than in the RRT group.

CONCLUSION

Compared to routine training, high-intensity progressive rehabilitation training is more effective. It reduces postoperative patient pain, accelerates recovery of joint function, increases patient satisfaction, improves quality of life, shortens hospital stays, and promotes rapid recovery.

The effectiveness of a combined exercise and psychological treatment programme on measures of nervous system sensitisation in adults with chronic musculoskeletal pain - a systematic review and meta-analysis

BACKGROUND

Quantitative sensory testing (QST) offers information regarding underlying mechanisms contributing to chronic pain (CP) in adults with musculoskeletal disorders. This review examined the use of QST measures in adults with CP following participation in a combined exercise and psychological intervention.

METHODS

The review was conducted in accordance with the PRISMA guidelines. Five databases were searched from inception to November 2022. All study designs which evaluated the effects of a combined exercise and psychological treatment on measures of nervous system sensitivity in adults with chronic musculoskeletal pain were included.

RESULTS

A total of 13 studies met the selection criteria, 10 of which were included in a meta-analysis. Local pressure pain thresholds were the most frequently used measure (n = 12 studies). Meta-analysis revealed statistically significantly improvements in favour of the combined exercise and psychological intervention group, compared to a control group, for local pressure pain threshold measures [SMD = 0.44, 95% CI 0.08-0.81, I2 = 84%], pain intensity scores [SMD=-0.89, 95% CI -1.66- -0.13, I2 = 94%] and the Central Sensitisation Inventory [SMD=-0.69, 95% CI -1.37- -0.02, I2 = 87%]. There were no significant differences found between groups for remote pressure pain thresholds, temporal summation or conditioned pain modulation.

CONCLUSIONS

The results suggest that a combined exercise and psychological intervention may lead to greater improvements in local pressure pain threshold, pain intensity and Central Sensitisation Inventory scores when compared to a control intervention in adults with CP, however these findings must be interpreted with caution as a large degree of heterogeneity was present in these results (I2: 84-94%). Further large, longitudinal studies are required using standardised QST measurement procedures and patient reported outcome measures to explore changes in nervous system sensitisation.

TRIAL REGISTRATION

This systematic review is registered with PROSPERO, ID Number CRD42022380464.

Tonic cuff pressure pain sensitivity in chronic pain patients and its relation to self-reported physical activity

OBJECTIVES

Physical inactivity is a global health concern and a significant problem among chronic pain patients. They often experience pain flare-ups when they try to increase their physical activity level. Most research on the relationship between pain sensitivity and physical activity has been on healthy participants. Data on chronic pain patients are lacking. Using cuff pressure algometry, this study investigated tonic cuff pressure pain sensitivity and its associations to self-reported physical activity and other patient-reported outcomes in chronic pain patients.

METHODS

Chronic pain patients (n=78) were compared to healthy controls (n=98). Multivariate data analysis was used to investigate the associations between tonic cuff pressure pain sensitivity, physical activity, and other patient-reported outcome measures.

RESULTS

The three most important variables for group discrimination were perceived health status (EQVAS: p(corr)=-0.85, i.e., lower in patients), depression (HADS-D: p(corr)=0.81, i.e., higher in patients), and the tonic cuff pressure pain sensitivity variable maximum pain intensity (VAS-peak-arm: p(corr)=0.75, i.e., higher in patients). In patients, the most important predictors for high VAS-peak-arm were female sex (p(corr)=-0.75), higher number of painful regions (p(corr)=0.72), higher pain intensity (p(corr)=0.55), followed by lower level of self-reported physical activity (p(corr)=-0.39). VAS-peak-arm in patients correlated negatively with self-reported physical activity (rho=-0.28, p=0.018).

CONCLUSIONS

Physical activity may be the most important patient-changeable variable correlating to pain sensitivity. This study highlights the importance of more research to further understand how increased physical activity may decrease pain sensitivity in chronic pain patients.

Outcomes Vary by Pre-Operative Physical Activity Levels in Total Knee Arthroplasty Patients

Physical activity (PA) is suggested to reduce osteoarthritis pain; however, it may be avoided by patients requiring arthroplasty. Our goal was to investigate objective and patient-reported outcomes as a function of pre-operative PA levels in patients undergoing total knee arthroplasty (TKA). A total of 1941 patients enrolled in a multicenter prospective cohort study investigating a smartphone-based care management platform for self-directed rehabilitation underwent TKA and were included in the analysis. Activity was categorized based on the cohort's step count quartiles into low, moderate, and high pre-operative PA. Pre-operative and post-operative pain, EQ5D5L, KOOS JR, and step counts were compared by ANOVA according to activity group. Pre-operative pain scores increased with the decreasing activity level (all, p < 0.05) and were most improved post-operatively in the low PA group. High PA patients demonstrated the smallest improvements in EQ-5D-5L and KOOS JR. Low and moderate PA patients increased physical activity by three months, reaching 176% and 104% of pre-operative steps; high PA patients did not return to full step counts by one year post-operatively. Patients undergoing TKA who present with higher levels of physical activity report lower levels of pain and higher function pre-operatively but appreciate less improvement up to one year post-operatively. These results may be helpful in appropriate counseling of patient expectations before TKA.

Summarizing the effects of different exercise types in chronic neck pain - a systematic review and meta-analysis of systematic reviews

BACKGROUND

To date, no consensus exists as to whether one exercise type is more effective than another in chronic neck pain. This systematic review and meta-analysis of systematic reviews aimed to summarize the literature on the effect of various exercise types used in chronic neck pain and to assess the certainty of the evidence.

METHODS

We searched the databases Ovid MEDLINE, Embase, Cochrane Library, SportDiscus, and Web of Science (Core Collection) for systematic reviews and meta-analyses on adults between 18 and 70 years with chronic neck pain lasting ≥ 12 weeks which investigated the effects of exercises on pain and disability. The included reviews were grouped into motor control exercise (MCE), Pilates exercises, resistance training, traditional Chinese exercise (TCE), and yoga. Study quality was assessed with AMSTAR-2 and the level of certainty for the effects of the exercise through GRADE. A narrative analysis of the results was performed and in addition, meta-analyses when feasible.

RESULTS

Our database search resulted in 1,794 systematic reviews. We included 25 systematic reviews and meta-analyses including 17,321 participants (overlap not accounted for). The quality of the included reviews ranged from critically low to low (n = 13) to moderate to high (n = 12). We found low to high certainty of evidence that MCE, Pilates exercises, resistance training, TCE, and yoga have short-term positive effects on pain and that all exercise types except resistance training, show positive effects on disability compared to non-exercise controls. We found low to moderate certainty of evidence for conflicting results on pain and disability when the exercise types were compared to other exercise interventions in the short-term as well as in intermediate/long-term apart for yoga, as no long-term results were available.

CONCLUSION

Overall, our findings show low to high certainty of evidence for positive effects on pain and disability of the various exercise types used in chronic neck pain compared to non-exercise interventions, at least in the short-term. Based on our results, no optimal exercise intervention for patients with chronic neck pain can be recommended, since no large differences between the exercise types were shown here. Because the quality of the included systematic reviews varied greatly, future systematic reviews need to increase their methodological quality.

TRIAL REGISTRATION

Prospero CRD42022336014.

The effectiveness of exercise with behavior change techniques in people with knee osteoarthritis: A systematic review with meta-analysis

OBJECTIVE

The purpose of this systematic review with meta-analysis was to examine the effectiveness of exercise with behavior change techniques (BCTs) on core outcome sets in people with knee osteoarthritis.

LITERATURE SURVEY

We searched randomized controlled trials (RCTs) in eight databases (MEDLINE, Embase, CENTRAL, CINAHL, PsycINFO, PEDro, ICTRP, and ClinicalTrials.gov) up to November 4, 2021.

METHODOLOGY

Eligible participants were people with knee osteoarthritis. The intervention was exercise with BCTs. Primary outcomes included physical function, quality of life (QOL) 6 to 12 months after intervention, and adverse events. Secondary outcomes were knee pain, exercise adherence, mobility, and self-efficacy 3 months or more after intervention. The bias risk was assessed using the Risk of Bias 2 tool. The random-effects model was used for the meta-analysis.

SYNTHESIS

We found 16 individual BCTs, and 37.7% of trials used a single BCT. For meta-analysis, we included 21 RCTs (n = 1623). Most outcomes had a very low certainty of evidence, and the risk of bias was the consistent reason for downgrading evidence levels. The standardized mean difference (SMD) with 95% confidence interval (95% CI) was 0.00 (-0.24, 0.24) in physical function, 0.33 (-0.51, 1.17) in exercise adherence, and 0.04 (-0.39, 0.47) in self-efficacy. The risk ratio (95% CI) of adverse events was 3.6 (0.79, 16.45). QOL was not pooled due to insufficient data (very low certainty of evidence). In contrast, the SMD (95% CI) for knee pain reduction and mobility improvement was -0.33 (-0.53, -0.13) and 0.21 (-0.05, 0.47) with moderate and low certainty of evidence, respectively.

CONCLUSION

The evidence is inconclusive regarding the effectiveness of BCTs with exercises on core outcome sets. Further research should explore the effectiveness of BCTs with valid design.

PROTOCOL REGISTRATION

PROSPERO (CRD42020212904).

Moderators of the effect of therapeutic exercise for knee and hip osteoarthritis: a systematic review and individual participant data meta-analysis

BACKGROUND

Many international clinical guidelines recommend therapeutic exercise as a core treatment for knee and hip osteoarthritis. We aimed to identify individual patient-level moderators of the effect of therapeutic exercise for reducing pain and improving physical function in people with knee osteoarthritis, hip osteoarthritis, or both.

METHODS

We did a systematic review and individual participant data (IPD) meta-analysis of randomised controlled trials comparing therapeutic exercise with non-exercise controls in people with knee osteoathritis, hip osteoarthritis, or both. We searched ten databases from March 1, 2012, to Feb 25, 2019, for randomised controlled trials comparing the effects of exercise with non-exercise or other exercise controls on pain and physical function outcomes among people with knee osteoarthritis, hip osteoarthritis, or both. IPD were requested from leads of all eligible randomised controlled trials. 12 potential moderators of interest were explored to ascertain whether they were associated with short-term (12 weeks), medium-term (6 months), and long-term (12 months) effects of exercise on self-reported pain and physical function, in comparison with non-exercise controls. Overall intervention effects were also summarised. This study is prospectively registered on PROSPERO (CRD42017054049).

FINDINGS

Of 91 eligible randomised controlled trials that compared exercise with non-exercise controls, IPD from 31 randomised controlled trials (n=4241 participants) were included in the meta-analysis. Randomised controlled trials included participants with knee osteoarthritis (18 [58%] of 31 trials), hip osteoarthritis (six [19%]), or both (seven [23%]) and tested heterogeneous exercise interventions versus heterogeneous non-exercise controls, with variable risk of bias. Summary meta-analysis results showed that, on average, compared with non-exercise controls, therapeutic exercise reduced pain on a standardised 0-100 scale (with 100 corresponding to worst pain), with a difference of -6·36 points (95% CI -8·45 to -4·27, borrowing of strength [BoS] 10·3%, between-study variance [τ2] 21·6) in the short term, -3·77 points (-5·97 to -1·57, BoS 30·0%, τ2 14·4) in the medium term, and -3·43 points (-5·18 to -1·69, BoS 31·7%, τ2 4·5) in the long term. Therapeutic exercise also improved physical function on a standardised 0-100 scale (with 100 corresponding to worst physical function), with a difference of -4·46 points in the short term (95% CI -5·95 to -2·98, BoS 10·5%, τ2 10·1), -2·71 points in the medium term (-4·63 to -0·78, BoS 33·6%, τ2 11·9), and -3·39 points in the long term (-4·97 to -1·81, BoS 34·1%, τ2 6·4). Baseline pain and physical function moderated the effect of exercise on pain and physical function outcomes. Those with higher self-reported pain and physical function scores at baseline (ie, poorer physical function) generally benefited more than those with lower self-reported pain and physical function scores at baseline, with the evidence most certain in the short term (12 weeks).

INTERPRETATION

There was evidence of a small, positive overall effect of therapeutic exercise on pain and physical function compared with non-exercise controls. However, this effect is of questionable clinical importance, particularly in the medium and long term. As individuals with higher pain severity and poorer physical function at baseline benefited more than those with lower pain severity and better physical function at baseline, targeting individuals with higher levels of osteoarthritis-related pain and disability for therapeutic exercise might be of merit.

FUNDING

Chartered Society of Physiotherapy Charitable Trust and the National Institute for Health and Care Research.

Quantitative sensory testing as an assessment tool to predict the response to standard pain treatment in knee osteoarthritis: a systematic review and meta-analysis

Emerging evidence suggest that quantitative sensory testing (QST) may predict the treatment response to pain-relieving therapies. This systematic review and meta-analysis focus on the predictive value of QST for pain management of knee osteoarthritis (OA). MEDLINE and EMBASE were systematically searched for all studies from year 2000 to 2023 on pretreatment QST and treatment of OA including surgical, pharmaceutical, and nonsurgical and nonpharmaceutical therapies. Preclinical studies and reviews were excluded. The systematic review followed the PRISMA guidelines and was pre-registered on the Open Science Framework website (link: https://osf.io/4FETK/, Identifier: DOI 10.17605/OSF.IO/4FETK). Meta-analysis were conducted to demonstrate the strength of the pre-treatment QST predictions on pain outcomes after OA treatments. Sixteen surgical (all on total knee arthroplasty [TKA], N = 1967), 5 pharmaceutical (4 on non-steroidal anti-inflammatory drugs [NSAIDs], N = 271), and 4 exercise-based therapy studies (N = 232) were identified. Pretreatment QST parameters predicted pain-relieving treatment outcomes in 81% of surgical, 100% of pharmaceutical, and 50% of exercise-based therapy studies. Meta-analyses found pretreatment QST profiles to predicted pain outcomes after TKA (random effects: 0.309, 95% confidence interval [CI]: 0.206-0.405, P < 0.001), NSAIDs (random effects: 0.323, 95% CI: 0.194-0.441, P < 0.001), and exercise-based therapies (random effects: 0.417, 95% CI: 0.138-0.635, P = 0.004). The overall risk of bias for the included studies was low to moderate. This systematic review and meta-analysis demonstrate weak-to-moderate associations between pretreatment QST and pain outcomes after standard OA pain treatments. Based on this work, it is hypothesized that a subset of specific pain sensitive patients with OA exist and that these patients do not respond adequately to standard OA pain treatments.

High- Versus Low-Dose Exercise Therapy for Knee Osteoarthritis : A Randomized Controlled Multicenter Trial

BACKGROUND

The benefits of exercise in patients with knee osteoarthritis are well documented, but the optimal exercise dose remains unknown.

OBJECTIVE

To compare high-dose versus low-dose exercise therapy with regard to knee function, pain, and quality of life (QoL) in patients with long-term symptomatic knee osteoarthritis.

DESIGN

A Swedish and Norwegian multicenter randomized controlled superiority trial with multiple follow-ups up to 12 months after the intervention. (ClinicalTrials.gov: NCT02024126).

SETTING

Primary health care facilities.

PATIENTS

189 patients with diagnosed knee osteoarthritis and a history of pain and decreased knee function were assigned to high-dose therapy (n = 98; 11 exercises; 70 to 90 minutes) or low-dose therapy (n = 91; 5 exercises; 20 to 30 minutes).

INTERVENTION

Patient-tailored exercise programs according to the principles of medical exercise therapy. Global (aerobic), semiglobal (multisegmental), and local (joint-specific) exercises were performed 3 times a week for 12 weeks under supervision of a physiotherapist.

MEASUREMENTS

The Knee Injury and Osteoarthritis Outcome Score (KOOS) was measured biweekly during the 3-month intervention period and at 6 and 12 months after the intervention. The primary end point was the mean difference in KOOS scores between groups at the end of the intervention (3 months). Secondary outcomes included pain intensity and QoL. The proportion of patients with minimal clinically important changes in primary and secondary outcomes was compared between groups.

RESULTS

Both groups improved over time, but there were no benefits of high-dose therapy in most comparisons. One exception was the KOOS score for function in sports and recreation, where high-dose therapy was superior at the end of treatment and at 6-month follow-up. A small benefit in QoL at 6 and 12 months was also observed.

LIMITATION

There was no control group that did not exercise.

CONCLUSION

The results do not support the superiority of high-dose exercise over low-dose exercise for most outcomes. However, small benefits with high-dose exercise were found for knee function in sports and recreation and for QoL.

PRIMARY FUNDING SOURCE

Swedish Rheumatic Fund.

Predicting pain after standard pain therapy for knee osteoarthritis - the first steps towards personalized mechanistic-based pain medicine in osteoarthritis

OBJECTIVES

The prevalence of osteoarthritis (OA) is rising, and pain is the hallmark symptom of OA. Pain in OA is complicated and can be influenced by multiple joint-related factors and factors related to, e.g., physiological, epigenetic, and pain sensory profiles. Increasing evidence suggests that a subset of patients with OA are pain sensitive. This can be assessed using quantitative sensory testing (QST). Common treatments of OA are total knee arthroplasty (TKA) and administration of 3-weeks of non-steroidal anti-inflammatory drugs (NSAIDs), which provide pain relief to many patients with OA. However, approx. 20% of patients experience chronic postoperative pain after TKA, whereas NSAIDs provide an average pain relief of approx. 25%. The current topical review focuses on the emerging evidence linking pretreatment QST to the treatment response of TKA and NSAID treatments.

CONTENT

MEDLINE was systematically searched for all studies from 2000 to 2022 on pretreatment QST, TKA, and NSAIDs. Pre-clinical studies, reviews, and meta-analyses were excluded.

SUMMARY

Currently, 14 studies on TKA and four studies on NSAIDs have been published with the aim to attempt prediction of the treatment response. The QST methodologies in the studies are inconsistent, but 11/14 (79%) studies on TKA and 4/4 (100%) studies on NSAIDs report statistically significant associations between pretreatment QST and chronic postoperative pain after TKA or analgesic effect after NSAID treatment. The strength of the associations remains low-to-moderate. The most consistent pretreatment QST predictors are pressure pain thresholds, temporal summation of pain, and conditioned pain modulation.

OUTLOOK

The use of QST as predictors of standard OA treatment is interesting, but the predictive strength remains low-to-moderate. A transition of QST from a research-based setting and into the clinic is not advised until the predictive strength has been improved and the methodology has been standardized.

Effects of Exercise-Induced Hypoalgesia at Different Aerobic Exercise Intensities in Healthy Young Adults

PURPOSE

Exercise-induced hypoalgesia (EIH) is a reduction in pain sensitivity that occurs following a single bout of exercise. However, little research has compared the EIH effects of exercise at different intensities, including low intensity, in the same participant. It is unclear as to which exercise intensities demonstrate EIH more effectively. The aim of this study was to examine and compare the effect of different intensities of exercise on pain sensitivity in the same participant.

METHODS

We included 73 healthy young adult volunteers (35 female and 38 male) in this experimental cross-over study. Each participant completed four experimental sessions of 30 min, consisting of aerobic exercise at 30% heart rate reserve (HRR), aerobic exercise at 50% HRR, aerobic exercise at 70% HRR, and quiet rest. EIH was assessed using the pressure pain threshold (PPT) and temporal summation of pain (TSP) in the quadriceps, biceps, and trapezius.

RESULTS

Low- and moderate-intensity exercise increased the multisegmental PPT and reduced TSP (all P < 0.05). High-intensity exercise increased the multisegmental PPT (all P < 0.05), but decreased TSP in only the quadriceps and biceps (P < 0.05), not the trapezius (P = 0.13). We found no difference in relative PPT and TSP changes between exercise intensities (P > 0.05) except for relative PPT change at the quadriceps (P < 0.05).

CONCLUSION

Our results show that not only moderate- and high-intensity exercise, but also low-intensity exercise can produce a hypoalgesic response.

Predictive Value of Pain Sensitization Associated with Response to Exercise Therapy in Patients with Knee Osteoarthritis: A Prospective Cohort Study

PURPOSE

Knee osteoarthritis (KOA) is a degenerative disease with inflammation, becoming persistent as it progresses, resulting in reduced quality of life. Exercise is the recommended treatment for KOA; however, the extent of pain reduction with exercise is heterogeneous and the prognostic implications of baseline factors in patients undergoing exercise are still unknown. This study examined the association between the response to exercise therapy and clinical outcomes, radiologic severity, and pain sensitization, and investigated the optimal predictive value for the effectiveness of exercise.

PATIENTS AND METHODS

Demographics, radiologic severity, pressure pain threshold (PPT), and temporal summation of pain (TSP) at the knee, tibia, and forearm were assessed at baseline. The pain numeric rating scale (NRS) was assessed before and after 12 weeks of exercise. Patients were divided into responder/non-responder groups according to recommended criteria: responder, ≥30% reduction in pain; non-responder, <30% reduction in pain, and each variable was compared between the groups. The area under the curve (AUC) and cutoff points were determined by receiver operating characteristic curve analysis.

RESULTS

Sixty-five patients were categorized as responders and 26 as non-responders. In the non-responder group, baseline NRS (P<0.01), pain duration (P<0.01), and TSP at the knee (P<0.001) and tibia (P<0.05) were significantly higher, and PPT at the knee (P<0.001), tibia (P<0.001), and forearm (P<0.001) were significantly lower, than those in the responder group; however, no significant differences between groups were found in other demographics and radiologic severity. The variables that showed moderate or better predictive ability (AUC≥0.7) were PPT at the knee (cutoff points: 241.5 kPa), tibia (307.5 kPa), forearm (318.5 kPa), and TSP at the knee (15.5 mm).

CONCLUSION

Our findings suggest that pain sensitization is associated with the response to exercise therapy. Furthermore, we provide clinically predictive values for PPT and TSP in predicting the outcome to exercise in KOA.

Training-induced hypoalgesia and its potential underlying mechanisms

It is well-established that a single bout of exercise can reduce pain sensitivity (i.e., exercise-induced hypoalgesia) in healthy individuals. However, exercise-induced hypoalgesia is often impaired in individuals with chronic pain. This might suggest that repeated bouts of exercise (i.e., exercise training) are needed in order to induce a reduction in pain sensitivity (i.e., training-induced hypoalgesia) among individuals with chronic pain, given that a single bout of exercise seems to be insufficient to alter pain. However, the effect of repeated bouts of exercise on pain sensitivity and its underlying mechanisms remain poorly understood. Therefore, the purpose of this review was to provide an overview of the existing literature on training-induced hypoalgesia, as well as discuss potential mechanisms of training-induced hypoalgesia and offer considerations for future research. Existing literature suggests that training interventions may induce hypoalgesic adaptations potentially driven by central nervous system and immune system factors. However, the limited number of randomized controlled trials available, along with the lack of understanding of underlying mechanisms, provides a rationale for future research.

Preventive Effects of a Single Bout of Exercise on Memory and Attention following One Night of Sleep Loss in Sports Students: Results of a Randomized Controlled Study

Sleep loss is a severe problem in night-shift workers. It causes fatigue and a decrease in awareness that may be counter-acted by exercise. This randomized controlled study of 22 university students investigated the effects of exercise to prevent loss of cognitive and physical performance following sleep deprivation. We compared a single bout of 20 min circuit training to control in an experimental setting of overnight sleep loss. Outcomes included memory, cognitive tasks, and physical parameters. The occurrence of false memories was considered the main outcome. Exercise did not exert significant effects on false memories (p = 0.456). We could detect a trend to significance (p < 0.01) assessing cognitive dimensions, i.e., selective and sustained attention, and visual scanning speed. This revealed strong effects of exercise on attention (p = 0.091; Cohen’s d = 0.76; ∆14%), cognitive performance, performance speed, and perceived sleepiness (p = 0.008; d = 0.60; ∆2.4 cm VAS). This study failed to show the effects of exercise on memory function. Still, the observed effects on attention and consciousness could be considered clinically relevant, as these results encourage further research to determine its practicability and meaningfulness among night-shift workers.

Pain Sensitization and Neuropathic Pain-like Symptoms Associated with Effectiveness of Exercise Therapy in Patients with Hip and Knee Osteoarthritis

Pain sensitization and neuropathic pain-like symptoms are some of the common pain symptoms in patients with lower limbs, including hip and knee, osteoarthritis (HOA/KOA). Exercise therapy has been the first-line treatment; however, the effects differ for each patient. This prospective cohort study investigated the relationship between the effectiveness of exercise therapy and pretreatment characteristics (radiologic severity, pain sensitization, and neuropathic pain-like symptoms) of patients with HOA/KOA. We assessed the pain intensity using a numerical rating scale (NRS) before and after 12 weeks of exercise therapy in patients with HOA/KOA (n = 101). Before treatment, the Kellgren–Lawrence (K-L) grade; minimum joint space width (mJSW); pressure pain threshold (PPT) and temporal summation of pain (TSP) at the affected joint, tibia, and forearm; Central Sensitization Inventory-9; and painDETECT questionnaire (PDQ) were assessed. Cluster analysis was based on the pretreatment NRS and change in NRS with exercise therapy to identify the subgroups of pain reduction. The pretreatment characteristics of each cluster were compared. According to the results of the cluster analyses, patients in cluster 1 had severe pain that did not improve after exercise therapy, patients in cluster 2 had severe pain that improved, and those in cluster 3 had mild pain that improved. The patients in cluster 1 exhibited lower PPT at all measurement sites, higher TSP at the affected joint, and higher PDQ scores than those in other clusters. There was no difference in the K-L grade and mJSW among the clusters. The subgroup with severe pain and pain sensitization or neuropathic pain-like symptoms at pretreatment, even with mild joint deformity, may have difficulty in achieving improvement in pain after 12 weeks of exercise therapy. These findings could be useful for prognosis prediction and for planning exercise therapy and combining with other treatment.

Effect of Neuromuscular Electrical Stimulation During Walking on Pain Sensitivity in Women With Obesity With Knee Pain: A Randomized Controlled Trial

OBJECTIVE

To assess the extent to which pain sensitivity is altered in women with obesity with frequent knee symptoms who walk with either a hybrid training system (HTS) that provides antagonist muscle electrical stimulation vs sensory transcutaneous electrical nerve stimulation (TENS).

DESIGN

Randomized, double-blinded, controlled trial.

SETTING

University-based fitness center.

PARTICIPANTS

Twenty-eight women (N=28) with obesity, aged 40-70 years, with daily knee symptoms.

INTERVENTIONS

Participants were randomized to 12 weeks of biweekly 30-minute walking exercise with either HTS (HTSW group) or sensory TENS (control group).

MAIN OUTCOME MEASURES

Pressure pain thresholds (PPTs) at the more symptomatic knee (local PPT) and PPT at the ipsilateral pain-free wrist (remote PPT).

RESULTS

After adjustment for preintervention values and body mass index (BMI), there was a statistically significant improvement in local PPT in the HTSW group compared with the control group (P=.039). After adjustment for pretraining value, age, and BMI, changes in remote PPT when comparing groups did not reach statistical significance, although the HTS group tended to demonstrate increased remote PPT (P=.052) compared with the control group. Moreover, after adjustment for pretraining value, knee pain, and quality of life, comparing groups did not reach statistical significance, although the HTS group tended to demonstrate decreased knee pain (P=.069) compared with the control group.

CONCLUSIONS

Augmentation of walking exercise with HTS was more effective than application of sensory TENS in improving local pain sensitivity at the knee but not at the wrist in women with obesity with frequent knee symptoms.

Voluntary exercise blocks ongoing pain and diminishes bone remodeling while sparing protective mechanical pain in a rat model of advanced osteoarthritis pain

ABSTRACT

Exercise is the most common treatment recommended by healthcare providers for the treatment of musculoskeletal pain. We examined whether voluntary running wheel exercise improves pain and bone remodeling in rats with monosodium iodoacetate-induced unilateral knee joint pain. During acquisition of wheel running before osteoarthritis (OA) treatment, rats separated into 2 groups characterized by either high or low levels of voluntary wheel running as indicated by distance and peak speed. After the induction of knee joint OA, all rats showed diminished voluntary wheel running throughout the study. Voluntary wheel running failed to alter evoked nociceptive responses evaluated as weight asymmetry or hind paw tactile thresholds at any timepoint of the study. By contrast, relief of ongoing pain was demonstrated by conditioned place preference produced by lidocaine injection into the monosodium iodoacetate-treated knee in high but not low-running rats. Both high and low voluntary runners showed diminished trabecular bone loss compared with sedentary controls. These observations indicate that both high-intensity and low-intensity exercise is beneficial in protecting against bone remodeling in advanced OA. The data suggest that similar to clinical observation, bone remodeling does not correlate with pain. In addition, these results suggest that higher intensity exercise may relieve persistent ongoing OA pain while maintaining movement-evoked nociception. The relief of ongoing pain can potentially offer significant improvement in quality of life, whereas preservation of responses to movement-evoked pain may be especially important in protecting the joint from damage because of overuse.

The burden of OA-health services and economics

Osteoarthritis (OA) is a highly prevalent and disabling condition that affects over 7% of people globally (528 million people). Prevalence levels are even higher in countries with established market economies, which have older demographic profiles and a higher prevalence of obesity, such as the US (14%). As the 15th highest cause of years lived with disability (YLDs) worldwide, the burden OA poses to individuals is substantial, characterized by pain, activity limitations, and reduced quality of life. The economic impact of OA, which includes direct and indirect (time) costs, is also substantial, ranging from 1 to 2.5% of gross national product (GNP) in countries with established market economies. In regions around the world, the average annual cost of OA for an individual is estimated between $700-$15,600 (2019 USD). Though trends in OA prevalence vary by geography, the prevalence of OA is projected to rise in regions with established market economies such as North America and Europe, where populations are aging and the prevalence of obesity is rising.

Redox interactions of immune cells and muscle in the regulation of exercise-induced pain and analgesia: implications on the modulation of muscle nociceptor sensory neurons

The mechanistic interactions among redox status of leukocytes, muscle, and exercise in pain regulation are still poorly understood and limit targeted treatment. Exercise benefits are numerous, including the treatment of chronic pain. However, unaccustomed exercise may be reported as undesirable as it may contribute to pain. The aim of the present review is to evaluate the relationship between oxidative metabolism and acute exercise-induced pain, and as to whether improved antioxidant capacity underpins the analgesic effects of regular exercise. Preclinical and clinical studies addressing relevant topics on mechanisms by which exercise modulates the nociceptive activity and how redox status can outline pain and analgesia are discussed, in sense of translating into refined outcomes. Emerging evidence points to the role of oxidative stress-induced signaling in sensitizing nociceptor sensory neurons. In response to acute exercise, there is an increase in oxidative metabolism, and consequently, pain. Instead, regular exercise can modulate redox status in favor of antioxidant capacity and repair mechanisms, which have consequently increased resistance to oxidative stress, damage, and pain. Data indicate that acute sessions of unaccustomed prolonged and/or intense exercise increase oxidative metabolism and regulate exercise-induced pain in the post-exercise recovery period. Further, evidence demonstrates regular exercise improves antioxidant status, indicating its therapeutic utility for chronic pain disorders. An improved comprehension of the role of redox status in exercise can provide helpful insights into immune-muscle communication during pain modulatory effects of exercise and support new therapeutic efforts and rationale for the promotion of exercise.

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.

Effects of exercise on knee osteoarthritis: A systematic review

BACKGROUND

Knee osteoarthritis is the most common joint disease and a major cause of functional limitation and pain in adults. The aim of this literature review is to review the existing evidence regarding the impact of exercise in people with knee osteoarthritis concerning physical and functional outcomes. The secondary aim is to provide both healthcare professionals and patients with updated and high-quality recommendations for the management of this condition.

METHODS

A systematic search was performed at Pubmed, Scopus and Web of Science databases, limiting the studies to English, French and Portuguese language, from 2010 to May 2020. Eligible studies were randomized control trials or clinical control trials that compared an intervention consisting of an exercise programme in adult participants with knee osteoarthritis against no intervention.

RESULTS

A total of 4499 studies were retrieved and 19 articles met the inclusion criteria. Beneficial effects of exercise were found on pain and strength. Regarding function, functional performance and quality of life, evidence is controversial. Both strengthening and aerobic exercise showed positive effects and both aquatic and land-based programmes presented improvement of pain, physical function and quality of life. Relatively to stretching, plyometric and proprioception training, no concrete conclusions can be taken.

CONCLUSION

Exercise programmes appear to be safe and effective in knee osteoarthritis patients, mainly regarding pain and strength improvement. Pilates, aerobic and strengthening exercise programmes performed for 8-12 weeks, 3-5 sessions per week; each session lasting 1 h appear to be effective. Both aquatic and land-based programmes show comparable and positive effects.

Masterclass: A pragmatic approach to pain sensitivity in people with musculoskeletal disorders and implications for clinical management for musculoskeletal clinicians

INTRODUCTION

Research on musculoskeletal disorders indicates that pain sensitivity can be an important consideration for musculoskeletal clinicians in the holistic view of a patient presentation. However, diversity in research findings in this field can make this a difficult concept for clinicians to navigate. Limited integration of the concept of pain sensitivity into clinical practice for musculoskeletal clinicians has been noted.

PURPOSE

The purpose of this masterclass is to provide a framework for the consideration of pain sensitivity as a contributing factor in the presentation of people with musculoskeletal pain. It provides pragmatic synthesis of the literature related to pain sensitivity through a lens of how this information can inform clinical practice for musculoskeletal clinicians. Guidance is provided in a 'how to' format for integration of this knowledge into the clinical encounter to facilitate personalised care.

IMPLICATIONS

The relationship of pain sensitivity with pain and disability is not clear or linear. The real importance of pain sensitivity in a clinical presentation may be: (1) the potential for pain sensitivity to modify the effect of common treatments utilised by musculoskeletal clinicians, or (2) the effect of pain sensitivity on the prognosis/course of a disorder. Screening tools and subjective features have been highlighted to indicate when physical assessment of pain sensitivity should be prioritised in the physical examination. A pragmatic blueprint for specific assessment related to pain sensitivity has been outlined. A framework for integrating assessment findings into clinical reasoning to formulate management plans for the pain sensitive patient is provided.

Is a Combination of Exercise and Dry Needling Effective for Knee OA?

OBJECTIVE

To assess the effectiveness of adding dry needling (DN) to an exercise program on pain intensity and disability in patients with knee osteoarthritis.

DESIGN

Double-blind randomized clinical trial with one-year follow-up.

SETTING

Older adults in a multicenter study.

SUBJECTS

Sixty-two patients with knee osteoarthritis were randomly allocated into one of two groups: exercise plus DN (exercise + DN; N = 31) or exercise plus sham DN (exercise + sham DN; N = 31).

METHODS

Participants received six sessions of either DN or sham DN over the leg muscles related to knee pain from osteoarthritis plus a supervised exercise program. We evaluated between-group differences in terms of the numerical pain rating scale (NPRS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. We used the EuroQol Group 5-Dimension Self-Report Questionnaire, Barthel Index, Timed Up & Go Test, and Global Rating of Change Scale to examine between-group differences for health-related quality of life, functional status evaluation, balance assessment, and clinical progress, respectively.

RESULTS

The groups were not different in terms of pain intensity (0.32 points, 95% confidence interval [CI] = -1.12 to 1.18, P = 0.92) or WOMAC score (0.29 points, 95% CI = -6.16 to 6.74, P = 0.92) at one year. Both groups presented within-group differences at all follow-up periods (F = 28.349, P < 0.0001, ηp2 = 0.32) on secondary outcomes. Nevertheless, 90.3% of the DN group had reduced medication consumption vs only 26.3% in the sham DN group.

CONCLUSIONS

The inclusion of DN to an exercise program does not reduce pain or disability in patients with knee osteoarthritis.

Exercise therapy and patient education versus intra-articular saline injections in the treatment of knee osteoarthritis: an evidence-based protocol for an open-label randomised controlled trial (the DISCO trial)

Background

Knee osteoarthritis (OA) is a highly prevalent musculoskeletal condition causing pain, physical disability, and reduced quality of life. Exercise and patient education are non-pharmacological interventions for knee OA unanimously recommended as first-line treatments based on extensive research evidence. However, none of the numerous randomised controlled trials of exercise and education for knee OA has used adequate sham/placebo comparison groups because the ‘active’ ingredients are unknown. Designing and executing an adequate and ‘blindable placebo’ version of an exercise and education intervention is impossible. Therefore, using an open-label study design, this trial compares the efficacy of a widely used ‘state-of-art’ exercise and education intervention (Good Life with osteoarthritis in Denmark; GLAD) with presumably inert intra-articular saline injections on improvement in knee pain in patients with knee OA.

Methods

In this open-label randomised trial, we will include 200 patients with radiographically verified OA of the knee and randomly allocate them to one of two interventions: (i) 8 weeks of exercise and education (GLAD) or (ii) Intra-articular injections of 5 ml isotonic saline every second week for a total of 4 injections. Outcomes are taken at baseline, after 8 weeks of treatment (week 9; primary endpoint) and after an additional 4 weeks of follow-up (week 12). The primary outcome is change from baseline in the Knee Injury and Osteoarthritis Outcome Score questionnaire (KOOS) pain subscale score. Secondary outcomes include the Physical function in Activities of Daily Living, Symptoms, and Knee-related Quality of Life subscales of the KOOS, the patients’ global assessment of disease impact, physical performance tests, and presence of knee joint swelling.

Discussion

This current trial compares a presumably active treatment (GLAD) with a presumably inert treatment (IA saline injections). Both study interventions have well-established and anticipated similar effects on knee OA symptoms, but the underlying mechanisms are unknown. The interpretation of the results of this trial will likely be difficult and controversial but will contribute to a better understanding of the bias introduced in the effect estimation of classically unblindable exercise and education interventions for knee OA.

Trial registration

www.ClinicalTrials.govNCT03843931. Prospectively registered on 18 February 2019.

The effect of exercise therapy on inflammatory activity assessed by MRI in knee osteoarthritis: Secondary outcomes from a randomized controlled trial

OBJECTIVE

This study investigated the effect of exercise therapy on inflammatory activity in synovitis and bone marrow lesions (BMLs) assessed by magnetic resonance imaging (MRI) in patients with knee OA.

METHODS

60 patients with knee OA were randomized 1:1 to 12 weeks of supervised exercise therapy 3 times/week (ET) or a no-attention control group (CG). Synovitis and BMLs were assessed with static MRI with and without contrast and with dynamic contrast enhanced MRI (DCE-MRI). DCE-MRI data was quantified using pixel-by-pixel methodology based on analysis of signal intensity curves. Pain was assessed by the Knee Injury and Osteoarthritis Outcome Score (KOOS). Analyses of covariance were used assessing group differences in changes from baseline to week 12.

RESULTS

33 patients adhered to the protocol and had valid MRI and KOOS data (ET, n = 16, CG, n = 17). Statistically significant and clinically relevant group difference in favour of ET was seen in KOOS pain change (-11.7 points, 95%CI: -20.1 to -3.4). There were statistically significant group differences in DCE-MRI assessed synovitis in the anterior synovium with unchanged inflammatory activity in the ET group compared to the CG. There were no group differences in BMLs and static MRI.

CONCLUSION

Inflammatory activity was unchanged, and pain was reduced in patients with knee OA adhering to 12 weeks of exercise therapy compared to a no-attention control group. The reduction in pain was not explained by changes in inflammatory activity. Overall, the results suggest that exercise is not harmful in knee OA. ClinicalTrials.gov number: NCT01545258.

Effect of exercise on pain processing and motor output in people with knee osteoarthritis: a systematic review and meta-analysis

OBJECTIVE

Guidelines recommend exercise as a core treatment for knee osteoarthritis. However, it is unclear how exercise affects measures of pain processing and motor function. The aim was to evaluate the effect of exercise on measures of pain processing and motor function in people with knee osteoarthritis.

METHODS

We searched five electronic databases (MEDLINE, EMBASE, CINAHL, SCOPUS and Cochrane Central Register of Controlled Trials) for studies on knee osteoarthritis, of any design, evaluating pain processing and motor function before and after exercise. Data were pooled with random-effects meta-analysis. Study quality was assessed using the Downs and Black and quality of evidence was assessed using the GRADE.

RESULTS

Eighteen studies were eligible and 16 were included. Following acute exercise, pressure pain threshold increased local to the study limb (standardised mean difference [95% confidence interval (CI)] 0.26, [0.02, 0.51], n = 159 from 5 studies), but there was no statistically significant change remote from the study limb (0.09, [-0.11, 0.29], n = 90 from 4 studies). Following an exercise program (range 5-12 weeks) there were no statistically significant changes in pressure pain threshold (local 0.23, [-0.01, 0.47], n = 218 from 8 studies; remote 0.33 [-0.13, 0.79], n = 76 from 4 studies), temporal pain summation (0.38 [-0.08, 0.85], n = 122 from 3 studies) or voluntary quadriceps muscle activation (4.23% [-1.84 to 10.30], n = 139 from 4 studies).

CONCLUSION

Very-low quality evidence suggests that pressure pain threshold increases following acute exercise. Very-low quality evidence suggests that pressure pain threshold, temporal pain summation or voluntary quadriceps activation do not change statistically significantly following exercise programs.

Changes in physical inactivity during supervised educational and exercise therapy in patients with knee osteoarthritis: A prospective cohort study

BACKGROUND

Physical inactivity is a global problem and patients with knee osteoarthritis (OA) are predisposed to inactivity and its health-related consequences. Current guidelines recommend exercise as primary treatment but whether this affects time spent physically inactive is unknown. The objective was to investigate changes in physical inactivity among individuals with knee OA following an educational and exercise program.

METHODS

Pragmatic prospective cohort study performed in six physical therapy clinics in Denmark offering a nationwide education and exercise program for knee OA. The program consists of physiotherapy guided education and group-based or home exercise sessions, performed biweekly for approximately eight weeks. The exercises target knee and hip joint stability as well as focus on increasing muscle strength. Primary outcome was time spent physically inactive (min/day), measured with a tri-axial accelerometer mounted on the lateral side of the thigh during the entire exercise program duration. OA symptoms were assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS).

RESULTS

Thirty-two individuals with knee OA were analyzed. From baseline to post-intervention, no changes occurred in average time spent physically inactive (mean change: +16.2 min [95% CI -15.7 to 48.1]; P = 0.31), but statistically significant improvements in KOOS pain (+6.7 points [95% CI 2.3 to 11.0]; P = 0.0032) and KOOS function (+5.8 points [95% CI 1.9 to 9.7]; P = 0.0046) were found.

CONCLUSIONS

Participating and completing a widely adopted education and exercise program are not associated with spontaneous improvements in physical inactivity despite changes in self-reported pain and function. Interventions specifically targeting physical inactivity are needed. Registration number: www.clinicaltrials.gov: NCT03125954.

Pain sensitivity is reduced by exercise training: Evidence from a systematic review and meta-analysis

BELAVY, D. L., J. Van Oosterwijck, M. Clarkson, E. Dhondt, N. L. Mundell, C. Miller and P. J. Owen. NEUROSCI BIOBEHAV REV 21(1) XXX-XXX, 2020. Exercise training is capable of reducing pain in chronic pain syndromes, yet its mechanisms are less well established. One mechanism may be via the impact of exercise on increasing a person's pain threshold. Here we show, via meta-analysis of fifteen exercise training studies in pain syndromes that exercise training leads to increased pressure pain thresholds (low to moderate quality evidence). We also find low to moderate quality evidence exists that exercise training was more effective than non-exercise interventions, such as pain education, massage and stress management for improving pain sensitivity. Further, the effect of exercise was greater locally at the site of pain and less so at remote regions. These finding suggest that adaptations in central inhibition occur over time with exercise training and, more widely, add to the mechanistic understanding of how effective interventions can improve pain in chronic pain syndromes.

Physiotherapeutic evaluation and intervention proposal on a patient with post-chikungunya chronic arthritis

BACKGROUND

Chikungunya fever is an arboviral disease characterized by a high morbidity rate related to intense and persistent arthralgia, causing a decrease in both quality of life (QoL) and productivity. This study aimed to report functional evaluation and multimodal physiotherapeutic intervention on a patient with post-chikungunya chronic arthritis (PCCA).

CASE PRESENTATION

Woman, 47 years old, resident of the municipality of Belém, state of Pará, northern Brazil, with clinical diagnosis of chikungunya fever marked by fever, swelling, pain in the joints of the hands and feet, and headache. The physiotherapeutic treatment started three months after the diagnosis and consisted of 24 sessions composed of electrotherapy, thermotherapy, and kinesiotherapy resources. The patient progressed from an initial status of intense pain in several joints to low pain in a single joint and showed improvement in all domains of QoL, mainly in limitations by physical and emotional aspects and functional capacity.

CONCLUSIONS

This case report details a proposal of multimodal physiotherapeutic intervention for a patient with functional impairments due to PCCA, suggesting that the use of physiotherapeutic resources may help this process and bring some assistance to those affected by the disease.

Exercise-induced hypoalgesia after acute and regular exercise: experimental and clinical manifestations and possible mechanisms in individuals with and without pain

This review describes methodology used in the assessment of the manifestations of exercise-induced hypoalgesia in humans and previous findings in individuals with and without pain. Possible mechanisms and future directions are discussed.

Exercise and physical activity is recommended treatment for a wide range of chronic pain conditions. In addition to several well-documented effects on physical and mental health, 8 to 12 weeks of exercise therapy can induce clinically relevant reductions in pain. However, exercise can also induce hypoalgesia after as little as 1 session, which is commonly referred to as exercise-induced hypoalgesia (EIH). In this review, we give a brief introduction to the methodology used in the assessment of EIH in humans followed by an overview of the findings from previous experimental studies investigating the pain response after acute and regular exercise in pain-free individuals and in individuals with different chronic pain conditions. Finally, we discuss potential mechanisms underlying the change in pain after exercise in pain-free individuals and in individuals with different chronic pain conditions, and how this may have implications for clinical exercise prescription as well as for future studies on EIH.

Utilizing the somatosensory system via vibratory stimulation to mitigate knee pain during walking: Randomized clinical trial

BACKGROUND

Pain and proprioception deficits are often associated with knee pathologies and resultant quadriceps muscle inhibition. There is a need for new approaches to mitigate active knee pain and restore muscle function during walking. Activating properties of the somatosensory system with common pain and sensory pathways offers a novel opportunity to enhance quadriceps function during walking.

RESEARCH QUESTION

Conduct a controlled clinical trial that investigates the effects of applying intermittent vibrational cutaneous stimulation during walking on knee pain and symptoms and their correlations to gait parameters.

METHODS

This longitudinal controlled cross-over clinical study included thirty-two patients randomly and blindly assigned to active Treatment A and passive Treatment B for 4 weeks with a 2-week washout period between treatments.

RESULTS

Subjects when wearing active Treatment A for 4 weeks had significant (p = 0.04) improvement in patient reported outcomes, while they had no significant differences with passive Treatment B (p > 0.7) compared to the no treatment condition. For Treatment A, subjects with low knee flexion moment and knee flexion angle in no-treatment condition exhibited the greatest increase in knee flexion moment/angle in the active treatment condition (R > 0.57, p < 0.001). These changes in gait measures were correlated significantly to changes in pain.

SIGNIFICANCE

This clinical trial indicates that knee pain can be reduced, and gait improved in a manner that enhances quadriceps function by applying intermittent cutaneous stimulation during gait in patients following knee injury or disease. The correlation between decreased pain and improved gait suggests that rehabilitation and exercise therapy may benefit from this treatment.

Efeito da fotobiomodulação associada a exercícios na dor e na funcionalidade de pacientes com osteoartrite de joelho: estudo-piloto

RESUMO O objetivo do estudo foi avaliar o efeito da fotobiomodulação associada a exercícios na dor e na funcionalidade de pacientes com osteoartrite de joelho. Para isso foram recrutados 20 pacientes com osteoartrite do joelho uni ou bilateral, que foram distribuídos em dois grupos: grupo-controle (GC), que realizou aplicação de fotobiomodulação (FBM) placebo e um protocolo de exercício; e grupo fotobiomodulação (GF), que realizou aplicação ativa da FBM e o protocolo de exercício, sendo esse realizado duas vezes por semana durante oito semanas e consistindo de alongamentos passivos dos músculos de membros inferiores, straight leg raise, treinamento proprioceptivo e exercícios para o controle da marcha. A FBM foi aplicada com o aparelho cluster contendo quatro diodos de 670 nm e cinco diodos de 850 nm, com uma potência de saída de 540 mW, sendo a dose utilizada de 4 J/cm2. Os grupos foram avaliados pré e pós-tratamento com os questionários SF-36, Lequesne, Tinetti, e por meio da Escala Visual Analógica de dor (EVA). Os dados foram analisados com o método Anova, seguido do Bonferroni. Os dados indicaram melhoras significativas para o GF ao fim do tratamento para as avaliações da EVA (2±1,25 vs. 0,7±0,82; p=0,009). Embora ambos os grupos tenham obtido melhoras significativas ao longo do tratamento, não foi possível observar diferenças significativas entre eles para o restante das avaliações ao final do tratamento. Portanto, conclui-se que o uso da FBM associada a exercícios apresentou melhora da dor nos pacientes com osteoartrite de joelho, embora não tenha sido possível observar diferenças significativas no que diz respeito à funcionalidade.

No detectable remodelling in adult human menisci: an analysis based on the C14 bomb pulse

Objectives

Bone and other human tissues remodel through life, for example, as a response to increasing load, and this prevents permanent destruction of the tissue. Non-traumatic meniscal rupture is a common musculoskeletal disease, but it is unknown if it is caused by inability of the menisci to remodel. The aim of this study was to determine whether meniscal collagen is remodelling throughout life.

Methods

The life-long turnover of the human meniscal collagens was explored by the ¹⁴C bomb pulse method. ¹⁴C levels were determined in menisci from 18 patients with osteoarthritis and 7 patients with healthy knees.

Results

There was a negligible turnover of the meniscal collagen in adults. This low turnover was observed in menisci from patients with knee osteoarthritis and in healthy menisci.

Conclusion

This study provides evidence that essentially no remodelling occurs in the adult human meniscal collagen structure and explains the clinical degeneration that is often seen in menisci of middle-aged and elderly persons. It suggests that strengthening of the collagen structure of menisci, as response to physical activity, may occur during childhood, while it is not possible in the adult population.

The Relationship Between Daily Physical Activity and Pain in Individuals with Knee Osteoarthritis

Objective

Investigate the association between physical activity and pain severity in individuals with knee osteoarthritis.

Design

Cross-sectional; systematic review with meta-analyses.

Methods

Thirty-one participants with knee osteoarthritis underwent assessment of symptoms via self-report questionnaires and quantitative sensory testing. Following testing, physical activity and symptoms were monitored for seven days using accelerometers and logbooks. Cross-correlation analyses were performed on fluctuations in symptoms and physical activity across the week to detect the relative timing of the strongest association between pain and activity. These data were complemented by meta-analyses of studies that examined correlations between pain from knee osteoarthritis and physical activity or fitness.

Results

Pain severity at baseline correlated with moderate to vigorous physical activity (r2 = 0.161–0.212, P &lt; 0.05), whereby participants who were more physically active had less pain. Conversely, the peak of the cross-correlation analyses was most often positive and lagging, which indicated that pain was increased subsequent to periods of increased activity. These superficially discrepant findings were supported by the results of a meta-analysis of 13 studies and 9,363 participants, which identified significant heterogeneity for associations between physical activity and pain (I2 = 91%). Stronger inverse associations were found between fitness and pain.

Conclusions

Associations between physical activity and pain in people with knee osteoarthritis are variable and dynamic. These results reflect the beneficial impact of an active lifestyle and accompanying higher fitness. Yet, the side effect of acute periods of physical activity to transiently exacerbate pain may influence the behavior of some people to avoid activity because of pain.

Relative Efficacy of Different Exercises for Pain, Function, Performance and Quality of Life in Knee and Hip Osteoarthritis: Systematic Review and Network Meta-Analysis

Background

Guidelines recommend exercise as a core treatment for osteoarthritis (OA). However, it is unclear which type of exercise is most effective, leading to inconsistency between different recommendations.

Objectives

The aim of this systematic review and network meta-analysis was to investigate the relative efficacy of different exercises (aerobic, mind–body, strengthening, flexibility/skill, or mixed) for improving pain, function, performance and quality of life (QoL) for knee and hip OA at, or nearest to, 8 weeks.

Methods

We searched nine electronic databases up until December 2017 for randomised controlled trials that compared exercise with usual care or with another exercise type. Bayesian network meta-analysis was used to estimate the relative effect size (ES) and corresponding 95% credibility interval (CrI) (PROSPERO registration: CRD42016033865).

Findings

We identified and analysed 103 trials (9134 participants). Aerobic exercise was most beneficial for pain (ES 1.11; 95% CrI 0.69, 1.54) and performance (1.05; 0.63, 1.48). Mind–body exercise, which had pain benefit equivalent to that of aerobic exercise (1.11; 0.63, 1.59), was the best for function (0.81; 0.27, 1.36). Strengthening and flexibility/skill exercises improved multiple outcomes at a moderate level. Mixed exercise was the least effective for all outcomes and had significantly less pain relief than aerobic and mind–body exercises. The trend was significant for pain (p = 0.01), but not for function (p = 0.07), performance (p = 0.06) or QoL (p = 0.65).

Conclusion

The effect of exercise varies according to the type of exercise and target outcome. Aerobic or mind–body exercise may be the best for pain and function improvements. Strengthening and flexibility/skill exercises may be used for multiple outcomes. Mixed exercise is the least effective and the reason for this merits further investigation.

Electronic supplementary material

The online version of this article (10.1007/s40279-019-01082-0) contains supplementary material, which is available to authorized users.

Impact of Therapeutic Interventions on Pain Intensity and Endogenous Pain Modulation in Knee Osteoarthritis: A Systematic Review and Meta-analysis

OBJECTIVE

To study the impact of therapeutic interventions on pain analgesia and endogenous pain modulation in knee osteoarthritis (KOA).

DESIGN

Systematic review and meta-analysis.

METHODS

We searched for KOA randomized clinical trials and observational studies with data on therapeutic interventions comparing pain intensity, temporal summation (TS), and conditioned pain modulation (CPM) scores relative to control. These data were pooled as Hedge's g. To study the relationship between pain intensity and TS/CPM, we performed metaregression with 10,000 Monte-Carlo permutations.

RESULTS

We reviewed 11 studies (559 participants). On studying all the interventions together, we found no significant changes in pain modulation, TS, or CPM. Our findings show that this lack of difference is likely because surgical and nonsurgical interventions resulted in contrary effects. Metaregression significantly correlated pain reduction with normalization of TS and CPM.

CONCLUSIONS

We demonstrate an association between pain reduction and TS/CPM normalization. Though we cannot directly compare these interventions, the results allow us to draw hypotheses on potential practice schemas. Recovering defective endogenous pain modulation mechanisms may help establish long-term analgesia. However, to validate these paradigms as robust clinical biomarkers, further investigation into their mechanisms would be necessary. The registration number for this review is CRD42017072066.

Exercise-induced pain changes associate with changes in muscle perfusion in knee osteoarthritis: exploratory outcome analyses of a randomised controlled trial

BACKGROUND

Exercise therapy is recommended for knee osteoarthritis (OA), but the underlying mechanisms of pain relief are not fully understood. The purpose of this study was to explore the effects of exercise on muscle perfusion assessed by dynamic contrast enhanced MRI (DCE-MRI) and its association with changes in pain in patients with knee OA.

METHODS

Exploratory outcome analyses of a randomised controlled study with per-protocol analyses ( ClinicalTrials.gov : NCT01545258) performed at an outpatient clinic at a public hospital in Denmark. We compared 12 weeks of supervised exercise therapy 3 times per week (ET) with a no attention control group (CG). Analyses of covariance (ANCOVA) were used to assess group mean differences in changes from baseline to week 12 in knee muscle perfusion quantified by DCE-MRI, patient-reported pain and function using the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire, knee extensor and flexor muscle strength tests, and the six-minute walking test (6MWT). Spearman's correlation coefficients were used to determine the correlation between changes in DCE-MRI variables, KOOS, muscle strength, and 6MWT. The potential effect mediation of the DCE-MRI perfusion variables was investigated in a post-hoc mediation analysis.

RESULTS

Of 60 participants randomised with knee osteoarthritis, 33 (ET, n = 16, CG, n = 17) adhered to the protocol and had complete DCE-MRI data. At follow-up, there were significant group differences in muscle perfusion changes and clinically relevant group differences in KOOS pain changes (10.7, 95% CI 3.3 to 18.1, P = 0.006) in favor of ET. There were no significant between-group differences on muscle strength and function. The changes in pain and muscle perfusion were significantly correlated (highest Spearman's rho = 0.42, P = 0.014). The mediation analyses were generally not statistically significant.

CONCLUSION

The pain-reducing effects of a 12-week exercise program are associated with changes in knee muscle perfusion quantified by DCE-MRI in individuals with knee OA, but whether the effects are mediated by muscle perfusion changes remains unclear.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01545258 , first posted March 6, 2012.

Quantitative sensory testing and predicting outcomes for musculoskeletal pain, disability, and negative affect: a systematic review and meta-analysis

Hypersensitivity due to central pain mechanisms can influence recovery and lead to worse clinical outcomes, but the ability of quantitative sensory testing (QST), an index of sensitisation, to predict outcomes in chronic musculoskeletal disorders remains unclear. We systematically reviewed the evidence for ability of QST to predict pain, disability, and negative affect using searches of CENTRAL, MEDLINE, EMBASE, AMED, CINAHL, and PubMed databases up to April 2018. Title screening, data extraction, and methodological quality assessments were performed independently by 2 reviewers. Associations were reported between baseline QST and outcomes using adjusted (β) and unadjusted (r) correlations. Of the 37 eligible studies (n = 3860 participants), 32 were prospective cohort studies and 5 randomised controlled trials. Pain was an outcome in 30 studies, disability in 11, and negative affect in 3. Meta-analysis revealed that baseline QST predicted musculoskeletal pain (mean r = 0.31, 95% confidence interval [CI]: 0.23-0.38, n = 1057 participants) and disability (mean r = 0.30, 95% CI: 0.19-0.40, n = 290 participants). Baseline modalities quantifying central mechanisms such as temporal summation and conditioned pain modulation were associated with follow-up pain (temporal summation: mean r = 0.37, 95% CI: 0.17-0.54; conditioned pain modulation: mean r = 0.36, 95% CI: 0.20-0.50), whereas baseline mechanical threshold modalities were predictive of follow-up disability (mean r = 0.25, 95% CI: 0.03-0.45). Quantitative sensory testing indices of pain hypersensitivity might help develop targeted interventions aiming to improve outcomes across a range of musculoskeletal conditions.

The role of hip abductor strength on the frontal plane of gait in subjects with medial knee osteoarthritis

OBJECTIVE

This study aimed to investigate the relationship of hip abductor strength with external hip and knee adduction moments, pain and physical function, and trunk, pelvis, and hip kinematics in the frontal plane during walking in subjects with medial knee osteoarthritis.

METHODS

Twenty-five subjects with medial knee osteoarthritis were evaluated through an isokinetic strength test for hip abductor, three-dimensional gait analysis (kinetics and kinematics), and pain and physical function scores. Regression models were used to control the influence of other parameters such as pain, age, gender, severity, walking speed, mass, and height.

RESULTS

No relationship was found of hip abductor strength with peak of external knee adduction moment and knee adduction angular impulse. Hip abductor strength explained 17% of contralateral pelvic drop and 21% of hip adduction angle. In addition, hip abductor strength explained 4% and 1% of the variance in the WOMAC physical function score and 40-m fast paced walk test, respectively.

CONCLUSION

Considering the relationship of hip abductor strength with contralateral pelvic drop and hip adduction angle, specific exercises might improve physical function and lower limb dynamic alignment during gait.