People with short symptom duration of knee osteoarthritis benefit more from exercise therapy than people with longer symptom duration: An individual participant data meta-analysis from the OA trial bank.

OBJECTIVE: To investigate whether duration of knee symptoms influenced the magnitude of the effect of exercise therapy compared to non-exercise control interventions on pain and physical function in people with knee osteoarthritis (OA). METHOD: We undertook an individual participant data (IPD) meta-analysis utilising IPD stored within the OA Trial Bank from randomised controlled trials (RCTs) comparing exercise to non-exercise control interventions among people with knee OA. IPD from RCTs were analysed to determine the treatment effect by considering both study-level and individual-level covariates in the multilevel regression model. To estimate the interaction effect (i.e., treatment x duration of symptoms (dichotomised)), on self-reported pain or physical function (standardised to 0-100 scale), a one-stage multilevel regression model was applied. RESULTS: We included IPD from 1767 participants with knee OA from 10 RCTs. Significant interaction effects between the study arm and symptom duration (≤1 year vs >1 year, and ≤2 years vs>2 years) were found for short- (~3 months) (Mean Difference (MD) -3.57, 95%CI -6.76 to -0.38 and -4.12, 95% CI-6.58 to -1.66, respectively) and long-term (~12 months) pain outcomes (MD -8.33, 95%CI -12.51 to -4.15 and -8.00, 95%CI -11.21 to -4.80, respectively), and long-term function outcomes (MD -5.46, 95%CI -9.22 to -1.70 and -4.56 95%CI -7.33 to-1.80, respectively). CONCLUSIONS: This IPD meta-analysis demonstrated that people with a relatively short symptom duration benefit more from therapeutic exercise than those with a longer symptom duration. Therefore, there seems to be a window of opportunity to target therapeutic exercise in knee OA.

Osteoarthritis year in review 2022: rehabilitation.

This year in review presents key highlights from research relating to osteoarthritis (OA) rehabilitation published from the 1st April 2021 to the 18th March 2022. To identify studies for inclusion in the review, an electronic database search was carried out in Medline, Embase and CINAHLplus. Following screening, included studies were grouped according to their predominant topic area, including core OA rehabilitation treatments (education, exercise, weight loss), adjunctive treatments, novel and emerging treatments or research methods, and translation of rehabilitation evidence into practice. Studies of perceived high clinical importance, quality, or controversy in the field were selected for inclusion in the review. Headline findings include: the positive role of technology to support remote delivery of core OA rehabilitation treatments, the importance of delivering educational interventions alongside exercise, the clinical and cost-effectiveness of a stepped approach to exercise, controversy around the potential mechanisms of action of exercise, mixed findings regarding the use of splinting for thumb base OA, increasing research on blood flow restriction training as a potential new intervention for OA, and evidence that the beneficial effects from core OA treatments seen in randomised controlled trials can be seen when implemented in clinical practice. A consistent finding across several recently published systematic reviews is that randomised controlled trials testing OA rehabilitation interventions are often small, with some risk of bias. Whilst future research is warranted, it needs to be large scale and robust, to enable definitive answers to important remaining questions in the field of OA rehabilitation.

Comparative effect of two educational videos on self-efficacy and kinesiophobia in people with knee osteoarthritis: an online randomised controlled trial.

OBJECTIVE: To compare change in self-efficacy for managing knee osteoarthritis (OA) pain and kinesiophobia after watching an educational video based on an empowerment and participatory discourse with a video based on a disease and impairment discourse. DESIGN: Two-arm randomised controlled trial with participants aged ≥45 years with knee pain (n = 589). Participants completed both baseline and follow-up outcomes and watched one randomly-allocated video (12-minute duration) during one 30-45-minute session within a single online survey. The experimental video presented evidence-based knee OA information using design and language that aimed to empower people and focus on activity participation to manage OA, while the control video presented similar information but with a disease and impairment focus. Primary outcome measures were Arthritis Self-Efficacy Scale pain subscale (range 0-10) and Brief Fear of Movement Scale for OA (range 6-24). Secondary outcomes were expectations about prognosis and physical activity benefits, perceived importance and motivation to be physically active, knee OA knowledge, hopefulness for the future, level of concern and perceived need for surgery. RESULTS: Compared to control (n = 293), the experimental group (n = 296) showed improved self-efficacy for managing OA pain (mean difference 0.4 [95%CI 0.2, 0.6] units) and reduced kinesiophobia (1.6 [1.1, 2.0] units). The experimental group also demonstrated greater improvements in all secondary outcomes apart from hopefulness, which was high in both groups. CONCLUSION: An educational video based on an empowerment and participatory discourse improved pain self-efficacy and reduced kinesiophobia in people with knee OA more than a video based on a disease and impairment discourse. CLINICALTRIALS: gov registration NCT05156216, Universal trial number U1111-1269-6143.

Effect of foot orthoses vs sham insoles on first metatarsophalangeal joint osteoarthritis symptoms: a randomized controlled trial.

OBJECTIVES: To compare contoured foot orthoses to sham flat insoles for first MTP joint OA walking pain. DESIGN: This was a participant- and assessor-blinded, sham-controlled, multi-centre randomized clinical trial set in community-based private practices. Eighty-eight adults aged ≥45 years with symptomatic radiographic first MTP joint OA were randomized to receive contoured foot orthoses (n = 47) or sham flat insoles (n = 41), worn at all times when wearing shoes for 12 weeks. Primary outcome was change in first MTP joint walking pain (11-point numerical rating scale (NRS), 0-10) over 12 weeks. Secondary outcomes included additional first MTP joint and foot pain measures, physical function, quality of life and physical activity. Separate linear regression models for primary and secondary outcomes on treatment group were fit, adjusting for the outcome at baseline and podiatrist. Other measures included adverse events. RESULTS: 88 participants were randomized and 87 (99%) completed the 12-week primary outcome. There was no evidence foot orthoses were superior to sham insoles for reducing pain (mean difference -0.3 NRS units (95% CI -1.2 to 0.6), p = 0.53). Similarly, foot orthoses were not superior to sham on any secondary outcomes. Sensitivity analyses yielded similar results. Adverse events were generally minor and transient. CONCLUSION: Contoured foot orthoses are no more effective than flat sham insoles for the clinical management of first MTP joint OA. Given the dearth of evidence on treatments for first MTP joint OA, further research is needed to identify effective management approaches for this common and debilitating condition.

Walking-related knee contact forces and associations with knee pain across people with mild, moderate and severe radiographic knee osteoarthritis: a cross-sectional study.

OBJECTIVE: To investigate knee contact forces (KCFs), and their relationships with knee pain, across grades of radiographic knee osteoarthritis (OA) severity. DESIGN: Cross-sectional exploratory analysis of 164 participants with medial knee OA. Radiographic severity was classified as mild (grade 2), moderate (grade 3) or severe (grade 4) using the Kellgren & Lawrence (KL) scale. Walking knee pain was assessed using an 11-point numerical rating scale. External knee adduction moment (external KAM) and internal muscle forces were used to calculate medial, lateral and total KCFs using a musculoskeletal computational model. Force-time series across stance phase of gait were compared across KL grades using Statistical Parametric Mapping. Associations between KCFs and pain across KL grades were assessed using linear models. RESULTS: Medial KCFs during early and middle stance were higher in participants with KL3 and KL4 compared to those with KL2. In contrast, lateral KCFs were higher in those with KL2 compared to KL3 and KL4 in middle to late stance. The external loading component (i.e., KAM) of the medial KCF during middle to late stance was also greater in participants with KL3 and KL4 compared to those with KL2, whereas the internal (i.e., muscle) component was greater in those with KL3 and KL4 compared to KL3 during early stance. There were no associations between medial KCF and knee pain in any KL grade. CONCLUSIONS: Medial and lateral KCFs differ between mild, moderate and severe radiographic knee OA but are not associated with knee pain severity for any radiographic OA grade.

How does hip osteoarthritis differ from knee osteoarthritis?

Hip and knee osteoarthritis (OA) are leading causes of global disability. Most research to date has focused on the knee, with results often extrapolated to the hip, and this extends to treatment recommendations in clinical guidelines. Extrapolating results from research on knee OA may limit our understanding of disease characteristics specific to hip OA, thereby constraining development and implementation of effective treatments. This review highlights differences between hip and knee OA with respect to prevalence, prognosis, epigenetics, pathophysiology, anatomical and biomechanical factors, clinical presentation, pain and non-surgical treatment recommendations and management.

"It's the single best thing I've done in the last 10 years": a qualitative study exploring patient and dietitian experiences with, and perceptions of, a multi-component dietary weight loss program for knee osteoarthritis.

OBJECTIVE: Explore patient and dietitian experiences with a multi-component dietary weight loss program for knee osteoarthritis to understand enablers and challenges to success at 6-months. DESIGN: Qualitative study embedded within a randomised controlled trial. Semi-structured individual interviews with 24 patients with knee osteoarthritis who undertook, and five dietitians who supervised, a weight management program (involving a ketogenic very low calorie diet (VLCD), video consultations, educational resources) over 6 months. Data were thematically analysed. RESULTS: Five themes were developed: (1) ease and convenience of program facilitated adherence (structure and simplicity of the meal replacements; not feeling hungry on diet; convenience of consulting via video) (2) social and professional support crucial for success (encouragement from partner, family, and friends; guidance from, and accountability to, dietitian; anxiety around going at it alone) (3) program was engaging and motivating (determination to stick to program; rapid weight loss helped motivation) (4) holistic nature of program was important (suite of high-quality educational resources; exercise important to compliment weight loss) (5) rewarding experience and lifelong impact (improved knee pain and function; positive lifestyle change). CONCLUSIONS: Patients and dietitians described positive experiences with the weight management program, valuing its simplicity, effectiveness, and convenience. Support from dietitians and a comprehensive suite of educational resources, incorporated with an exercise program, were considered crucial for success. Findings suggest this multi-component dietary program is an acceptable weight loss method in people with knee osteoarthritis that may benefit symptoms. Strategies for supporting long-term independent weight management should be a focus of future research.

Can pain flares in knee osteoarthritis be predicted?

Objectives: This study examined whether risk factors for knee osteoarthritis (KOA) pain such as age, gender, body mass index (BMI), baseline pain, and other putative risk factors for knee osteoarthritis pain flares (KOAF) (e.g. knee buckling, injury, mood/stress/social support scores, and footwear) could predict KOAF.Method: People with KOA and previous history of KOAF were selected from a 3 month web-based longitudinal study. KOAF was defined as an increase of ≥ 2 points on a numeric rating scale (compared with background pain) which resolved within 20 days. Predictors assessed at baseline were gender, age, duration of KOA, BMI, pain, knee injury (7 days before), knee buckling (2 days before), Lubben Social Support, Knee Injury and Osteoarthritis Outcome Score, Intermittent and Constant Osteoarthritis Pain score (ICOAP), Positive/Negative Affect Score, and footwear stability/heel height. Outcome was occurrence of any KOAF during the ensuing 30 days. The combined ability of the above variables to predict occurrence of any KOAF was evaluated by multiple logistic regression with a 10-fold cross-validation method to build and internally validate the model. Variables that assessed similar domains were eliminated using receiver operating characteristics curve assessment for best fit.Results: Complete data were available for 313 people (66.6% female, mean ± sd age 62.3 ± 8.2 years, BMI 29.7 ± 6.5 kg/m2). Increasing age, years of osteoarthritis, BMI, background/worst levels of pain, knee injury, knee buckling, ICOAP, and footwear category/heel height significantly predicted the occurrence of KOAF during the following 30 days, with an area under the curve of 0.73 (95% confidence interval 0.67-0.80).Conclusion: A combination of risk factors assessed at baseline, including exposures with potential to vary, successfully predicts the KOAF in the ensuing 30 days.

Association of weather factors with the risk of pain exacerbations in people with hip osteoarthritis.

Objectives: Our objective was to evaluate the association of weather factors with the risk of pain exacerbations in people with symptomatic hip osteoarthritis (OA). Method: Eligible participants with symptomatic hip OA were instructed to log on to the study website and complete questionnaires every 10 days and additionally whenever they considered they were experiencing a pain exacerbation (case period) during the 90 day follow-up. Pain exacerbation was defined as an increase of two points in pain intensity on an 11-point numeric rating scale (0-10) during the follow-up compared with baseline. Each case period was anchored to four control periods within a 35 day interval using a time-stratified approach. Weather data were obtained for both periods from the publicly available meteorological database of the Australian Bureau of Meteorology. We examined the association of weather factors across 72 h before the index date with the risk of pain exacerbation, using conditional logistic regression. Results: Among 252 participants recruited, 129 participants had at least one episode of pain exacerbation and were included in the analysis. A significant dose-response relationship was found between average daily temperature variation in the prior 72 h and risk of pain exacerbations (p = 0.04 for linear trend). There was no significant association between maximum daily temperature, minimum daily temperature, relative humidity, precipitation, or barometric pressure and hip pain exacerbations. Conclusion: The overall results suggest that only daily temperature variation among different weather factors was associated with hip pain exacerbations in people with symptomatic hip OA.

What type of exercise is most effective for people with knee osteoarthritis and co-morbid obesity?: The TARGET randomized controlled trial.

OBJECTIVE: Different exercise types may yield different outcomes in osteoarthritis (OA) subgroups. The objective was to directly compare effectiveness of two exercise programs for people with medial knee OA and co-morbid obesity. DESIGN: We performed a participant- and assessor-blinded randomized controlled trial. 128 people ≥50 years with medial knee OA and body mass index ≥30 kg/m2 were recruited from the community. Interventions were home-based non-weight bearing (NWB) quadriceps strengthening or weight bearing (WB) functional exercise for 12 weeks. Primary outcomes were change in overall knee pain (numeric rating scale, range 0-10) and difficulty with physical function (Western Ontario and McMaster Universities Osteoarthritis Index, 0-68) over 12 weeks. Secondary outcomes included other pain measures, physical function, quality-of-life, global changes, physical performance, and lower-limb muscle strength. RESULTS: 123 (96%) participants were retained. There was no evidence of a between-group difference in change in pain (mean difference 0.73 units (95% confidence intervals (0.05,1.50)) or function (2.80 units (-1.17,6.76)), with both groups reporting improvements. For secondary outcomes, the WB group had greater improvement in quality-of-life (-0.043 units (-0.085,-0.001)) and more participants reporting global improvement (overall: relative risk 1.40 (0.98,2.01); pain 1.47 (0.97,2.24); function 1.43 (1.04,1.98). Although adverse events were minor, more NWB group participants reported ≥1 adverse event (26/66 (39%) vs 14/62 (23%), p = 0.04). CONCLUSIONS: Both exercise types similarly improved primary outcomes of pain and function and can be recommended for people with knee OA and obesity. WB exercise may be preferred given fewer adverse events and potential additional benefits on some secondary outcomes. REGISTRATION: Prospectively registered (Australian New Zealand Clinical Trials Registry #12617001013358, 14/7/2017).

Development of a core capability framework for qualified health professionals to optimise care for people with osteoarthritis: an OARSI initiative.

OBJECTIVE: Develop a generic trans-disciplinary, skills-based capability framework for health professionals providing care for people with OA. DESIGN: e-Delphi survey. An international inter-professional Delphi Panel (researchers; clinicians; consumer representatives) considered a draft framework (adapted from elsewhere) of 131 specific capabilities mapped to 14 broader capability areas across four domains (A: person-centred approaches; B: assessment, investigation and diagnosis; C: management, interventions and prevention; D: service and professional development). Over three rounds, the Panel rated their agreement (Likert or numerical rating scales) on whether each specific capability in Domains B and C was essential (core) for all health professionals when providing care for all people with OA. Those achieving consensus (≥80% of Panel) rating of ≥ seven out of ten (Round 3) were retained. Generic domains (A and D) were included in the final framework and amended based on Panel comments. RESULTS: 173 people from 31 countries, spanning 18 disciplines and including 26 consumer representatives, participated. The final framework comprised 70 specific capabilities across 13 broad areas i) communication; ii) person-centred care; iii) history-taking; iv) physical assessment; v) investigations and diagnosis; vi) interventions and care planning; vii) prevention and lifestyle interventions; viii) self-management and behaviour change; ix) rehabilitative interventions; x) pharmacotherapy; xi) surgical interventions; xii) referrals and collaborative working; and xiii) evidence-based practice and service development). CONCLUSION: Experts agree that health professionals require an array of skills in person-centred approaches; assessment, investigation and diagnosis; management, interventions and prevention; and service and professional development to provide optimal care for people with OA.

Effect of cane use on bone marrow lesion volume in people with medial tibiofemoral knee osteoarthritis: randomized clinical trial.

OBJECTIVE: To evaluate effects of daily cane use for 3 months on medial tibiofemoral bone marrow lesion (BML) volumes in people with medial tibiofemoral osteoarthritis (OA). DESIGN: In this randomized controlled trial (RCT), 79 participants with medial tibiofemoral OA were randomized to either a cane group (using a cane whenever walking) or control group (not using any gait aid) for 3 months. The cane group received a single training session by a physiotherapist, using a biofeedback cane to teach optimal technique and body weight support and motor learning principles to facilitate retention of learning. The primary outcome was change in total medial tibiofemoral BML volume (per unit bone volume) measured from magnetic resonance imaging (MRI) at 3 months. Secondary outcomes were BML volumes (per unit bone volume) of the medial tibia and femur, and patient-reported outcomes of overall knee pain, knee pain on walking, physical function, perceived global symptom changes and health-related quality of life. MRI analyses were performed by a blinded assessor. RESULTS: Seventy-eight participants (99%) completed the primary outcome. Mean (standard deviation) daily cane use was 2.3 (1.7) hours over 3 months. No evidence of between-group differences was found for change in total medial tibiofemoral BML volume (mean difference: -0.0010 (95% confidence intervals: -0.0022, 0.0003)). Most secondary outcomes showed minimal differences between groups. CONCLUSION: Daily use of a cane during walking for 3 months aiming to reduce knee joint loading did not change medial tibiofemoral BML volumes compared to no use of gait aids. CLINICAL TRIAL REGISTRATION: Australian New Zealand Clinical Trial Registry (ACTRN12614000909628).

Health professionals and students encounter multi-level barriers to implementing high-value osteoarthritis care: a multi-national study.

OBJECTIVE: Consistent evidence-practice gaps in osteoarthritis (OA) care are observed in primary care settings globally. Building workforce capacity to deliver high-value care requires a contemporary understanding of barriers to care delivery. We aimed to explore barriers to OA care delivery among clinicians and students. DESIGN: A cross-sectional, multinational study sampling clinicians (physiotherapists, primary care nurses, general practitioners (GPs), GP registrars; total possible denominator: n = 119,735) and final-year physiotherapy and medical students (denominator: n = 2,215) across Australia, New Zealand and Canada. Respondents answered a survey, aligned to contemporary implementation science domains, which measured barriers to OA care using categorical and free-text responses. RESULTS: 1886 clinicians and 1611 students responded. Items within the domains 'health system' and 'patient-related factors' represented the most applicable barriers experienced by clinicians (25-42% and 20-36%, respectively), whereas for students, 'knowledge and skills' and 'patient-related factors' (16-24% and 19-28%, respectively) were the most applicable domains. Meta-synthesis of qualitative data highlighted skills gaps in specific components of OA care (tailoring exercise, nutritional/overweight management and supporting positive behaviour change); assessment, measurement and monitoring; tailoring care; managing case complexity; and translating knowledge to practice (especially among students). Other barriers included general infrastructure limitations (particularly related to community facilities); patient-related factors (e.g., beliefs and compliance); workforce-related factors such as inconsistent care and a general knowledge gap in high-value care; and system and service-level factors relating to financing and time pressures, respectively. CONCLUSIONS: Clinicians and students encounter barriers to delivery of high-value OA care in clinical practice/training (micro-level); within service environments (meso-level); and within the health system (macro-level).

"I was really sceptical...But it worked really well": a qualitative study of patient perceptions of telephone-delivered exercise therapy by physiotherapists for people with knee osteoarthritis.

OBJECTIVE: Physiotherapists typically prescribe exercise therapy for people with osteoarthritis (OA) via face-to-face consultations. This study aimed to explore peoples' perceptions of exercise therapy delivered by physiotherapists via telephone for their knee OA. DESIGN: A qualitative study (based on interpretivist methodology) embedded within a randomised controlled trial. Semi-structured individual interviews were conducted with 20 people with knee OA who had received exercise advice and support from one of eight physiotherapists via telephone over 6 months. Interviews were audio recorded, transcribed verbatim and thematically analysed. RESULTS: Although people with OA were initially sceptical about receiving exercise therapy via telephone, they described mostly positive experiences, valuing the convenience and accessibility. However, some desired visual contact with the physiotherapist and suggested including video-conferencing calls or an initial in-person clinic visit. Participants valued the sense of undivided focus and attention they received from the physiotherapist and believed that they were able to communicate effectively via telephone. Participants felt confident performing their exercise program without supervision and described benefits including increased muscular strength, improved pain, and ability to perform tasks that they had not been previously able to. CONCLUSIONS: People with knee OA held mostly positive perceptions about receiving exercise therapy from a physiotherapist via telephone, suggesting that such a service is broadly acceptable to consumers. Such services were generally not viewed as a substitute for face-to-face physiotherapy care, but rather as a new option that could increase accessibility of physiotherapy services, particularly for follow-up consultations.

Trajectories of adherence to home-based exercise programs among people with knee osteoarthritis.

OBJECTIVE: To investigate the presence of different trajectories of self-reported adherence to home exercise programs among people with knee osteoarthritis (OA), and to compare baseline characteristics across identified groups. DESIGN: Pooled analysis of data from three randomised controlled trials involving exercise interventions for people aged ≥50 years with clinical knee OA (n = 341). Exercise adherence was self-reported on an 11-point numerical rating scale (NRS; 0 = not at all-10 = completely as instructed). Latent class growth analysis was used to identify distinct trajectories of adherence, at intervals from 12 to 78 weeks from baseline. Baseline characteristics of these groups were compared using chi-squared tests, one-way analysis of variance (ANOVA) and Kruskal Wallis tests where appropriate. RESULTS: Three distinct adherence trajectories were identified: a "Rapidly declining adherence" group (n = 157, 47.4%) whose adherence was 7.7 ± 1.6 (/10) at 12 weeks, declined to 4.2 ± 2.2 by 22 weeks and remained low thereafter; a "Gradually declining adherence" group (n = 153, 45.1%) whose adherence declined from 8.5 ± 1.5 to 7.8 ± 1.5 over the same period, and continued to decline slowly, and a "Low adherence" group (n = 21, 6.3%) whose adherence was 2.2 ± 1.4 at 12 weeks and remained low. At baseline the "Rapidly declining adherence" group reported significantly lower Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain (mean difference (95% Confidence Interval (CI)) -0.8 (-1.4, -0.2)) and better WOMAC function compared to the "Gradually declining adherence" group (-3.1 (-5.2, -1.1)). CONCLUSION: Three trajectories of self-reported adherence to home exercises were found among people with knee OA. Findings highlight the need for close monitoring of adherence from initiation of a home exercise program in order to identify and intervene when low or rapidly declining adherence is identified.

Management of foot/ankle osteoarthritis by Australian general practitioners: an analysis of national patient-encounter records.

OBJECTIVE: To document the management of foot/ankle osteoarthritis/arthritis (OA) by general practitioners (GP) in Australia. DESIGN: We analysed data from the Bettering the Evaluation and Care of Health Program April 2010-March 2016 inclusive. Patient and GP encounter characteristics were extracted. Data were classified by the International Classification of Primary Care, Version 2, and summarised using descriptive statistics and 95% confidence intervals (95% CIs) around point estimates. RESULTS: The dataset included 583,900 patient-encounter records among which foot/ankle OA was managed 621 times, at a rate of 1.1 per 1000 encounters, with an annual estimated 152,000 GP encounters nationally. The management rate was most frequent among patients aged 65-74 years (2.25 per 1000 encounters). Comorbidities were managed at a rate of 105.8 per 100 encounters, the most common being hypertension, and few being other musculoskeletal problems. Foot/ankle OA was mostly managed using medication (64.6 per 100 problems), with prescription rates far exceeding non-pharmacological strategies such as counselling, advice or education (17.7 per 100), or allied health referral (10.1 per 100). When considering specific health/medical professionals, patients were referred to orthopaedic surgeons 8.4 times per 100 foot/ankle problems, podiatrists 6.3 times per 100 foot/ankle problems, and physiotherapists 2.6 times per 100 foot/ankle problems. CONCLUSIONS: Pharmacological management rates of foot/ankle OA were high and substantially exceeded non-pharmacological management such as lifestyle advice and allied health referral. Longitudinal studies are needed to determine the effectiveness of this care compared to self-management and conservative non-drug treatment in people with foot/ankle OA.

Knee extensor strength gains mediate symptom improvement in knee osteoarthritis: secondary analysis of a randomised controlled trial.

OBJECTIVE: To determine if an increase in knee extensor strength mediates the effect of a 12-week knee extensor strength training program on pain and physical function improvement in people with knee osteoarthritis (OA). DESIGN: Secondary analysis from a randomised controlled trial comparing the effects of a 12-week knee extensor strengthening exercise program to a control group with no intervention. METHODS: Data from participants with complete data (n = 97) enrolled in a previous clinical trial were analysed. Baseline and 12-week follow-up assessments included peak isometric knee extensor strength, pain and physical function. Peak knee extensor strength (Nm/kg) was assessed on an isokinetic dynamometer and subscales of the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index were used to assess pain and physical function. Twelve-week change in pain and physical function were regressed separately, on 12-week change in knee extensor strength and group allocation. Covariates included baseline pain or physical function as appropriate, and baseline knee extensor strength, age, sex and knee alignment (stratification variable). RESULTS: Improved knee extensor strength mediated the effect of the strengthening program on both pain relief (mediated effect size = 0.69, 95% confidence intervals (CI) 0.05-1.33, P = 0.03), and improved physical function (mediated effect size = 1.86, 95% CI 0.08-3.64, P = 0.04), at 12 weeks. CONCLUSIONS: Increased knee extensor strength partially mediates the effect of a knee extensor strength training program on pain and physical function improvement in people with knee OA.

Moderators and mediators of effects of unloading shoes on knee pain in people with knee osteoarthritis: an exploratory analysis of the SHARK randomised controlled trial.

OBJECTIVE: To investigate moderators and biomechanical mediators of effects of unloading shoes on knee pain in people with knee osteoarthritis (OA). METHODS: Exploratory analysis from 164 participants in a clinical trial comparing unloading (ASICS GEL-Melbourne OA) to conventional walking shoes. The primary outcome was 6-month change in knee pain (11-point numerical rating scale (NRS)). Moderators included baseline peak knee adduction moment (KAM), radiographic severity (Kellgren & Lawrence (KL) scale), body mass, foot posture, neuropathic pain and diffuse knee pain. Mediators included change in peak KAM and KAM impulse. RESULTS: Radiographic severity was the only moderator to interact with footwear group (P = 0.02). Participants with KL = 2 experienced greater pain reductions with conventional compared to unloading shoes (mean difference in change in pain -1.64 units, 95% CI -3.07, -0.21), while unloading shoes tended to result in greater pain reductions than conventional shoes in KL = 3 (0.98, 95% CI -0.44, 2.39) and KL = 4 (0.64, 95% CI -0.64, 1.93). No variable showed any significant mediating effect in the entire cohort. However, there was some evidence that unloading shoes may reduce pain through reductions in peak KAM (indirect effect -0.31, 95% CIs -0.65, 0.03; P = 0.07) in people with KL ≥ 3, compared to conventional shoes. CONCLUSION: Unloading shoes conferred additional symptomatic benefits over conventional shoes in people with moderate to severe knee OA. There was some evidence effects may be mediated by a reduction in peak KAM. However, we were underpowered for subgroup analyses. These patients may represent a subgroup to which biomechanical interventions designed to reduce the KAM may be more effectively targeted.

Hip abductor muscle activity during walking in individuals with gluteal tendinopathy.

The external hip adduction moment during walking is greater in individuals with gluteal tendinopathy (GT) than pain-free controls. Although this likely represents a greater demand on the hip abductor muscles implicated in GT, no study has investigated activation of these muscles in GT. For this purpose, fine wire electrodes were inserted into the segments of the gluteus minimus and medius muscles, and surface electrodes placed on the tensor fascia lata, upper gluteus maximus, and vastus lateralis muscles of eight individuals with, and eight without, GT. Participants underwent six walking trials. Individual muscle patterns were compared between groups using a wavelet-based linear effects model and muscle synergy analysis performed using non-negative matrix factorization to evaluate muscle activation patterns, within- and between-participant variability. Compared to controls, individuals with GT exhibited a more sustained initial burst of the posterior gluteus minimus and middle gluteus medius muscle segments. Two muscle synergies were identified; Synergy-1 activated in early-mid stance and Synergy-2 in early stance. In GT participants, posterior gluteus minimus and posterior gluteus medius and tensor fascia lata contributed more to Synergy-1 active during the period of single leg support. Participants with GT exhibited reduced within-participant variability of posterior gluteus medius and reduced between-participant variability of anterior gluteus minimus and medius and upper gluteus maximus. In conclusion, individuals with GT exhibit modified muscle activation patterns of the hip abductor muscles during walking, with potential relevance for gluteal tendon loading.

Correction to: Effectiveness of a new model of primary care management on knee pain and function in patients with knee osteoarthritis: Protocol for THE PARTNER STUDY.

After the publication of this protocol [1], our collaborator Prima Health solutions advised us of their intent to withdraw from the study.