Development of a Multimodal, Personalized Intervention of Virtual Reality Integrated Within Physiotherapy for Patients With Complex Chronic Low-Back Pain.

Background: Chronic low-back pain (CLBP) is the leading cause of years lived with disability. Physiotherapy is the most common treatment option for CLBP, but effects are often unsatisfactory. Virtual reality (VR) offers possibilities to enhance the effectiveness of physiotherapy treatment. Primary aim was to develop and test a personalized VR intervention integrated within a physiotherapy treatment for patients with CLBP. Methods: This study describes an intervention development process using mixed methods design that followed the Medical Research Council (MRC) framework. This involved a cocreation process with patients, physiotherapists, and researchers. A draft intervention was constructed based on a literature review and focus groups, and subsequently tested in a feasibility study and evaluated in focus groups. Focus group data were analyzed using thematic analysis. This intervention development process resulted in a final intervention. Results: Focus group data showed that VR and physiotherapy can strengthen each other when they are well integrated, and that VR needs to be administered under the right conditions including flawless technology, physiotherapists with sufficient affinity and training, and the right expectations from patients. The draft intervention was considered feasible after evaluation by four patients and three physiotherapists and was further complemented by expanding the training for physiotherapists and improving the protocols for physiotherapists and patients. The final intervention consisted of a 12-week physiotherapy treatment with three integrated VR modules: pain education, physical exercise, and relaxation. Conclusion: Using the MRC framework in cocreation with the end users, a personalized VR intervention integrated within a physiotherapy treatment for patients with CLBP was developed. This intervention was found to be feasible and will subsequently be evaluated for (cost-)effectiveness in a cluster randomized controlled trial.

Limited use of virtual reality in primary care physiotherapy for patients with chronic pain.

BACKGROUND: Chronic pain is a disabling condition which is prevalent in about 20% of the adult population. Physiotherapy is the most common non-pharmacological treatment option for chronic pain, but often demonstrates unsatisfactory outcomes. Virtual Reality (VR) may offer the opportunity to complement physiotherapy treatment. As VR has only recently been introduced in physiotherapy care, it is unknown to what extent VR is used and how it is valued by physiotherapists. The aim of this study was to analyse physiotherapists' current usage of, experiences with and physiotherapist characteristics associated with applying therapeutic VR for chronic pain rehabilitation in Dutch primary care physiotherapy. METHODS: This online survey applied two rounds of recruitment: a random sampling round (873 physiotherapists invited, of which 245 (28%) were included) and a purposive sampling round (20 physiotherapists using VR included). Survey results were reported descriptively and physiotherapist characteristics associated with VR use were examined using multivariable logistic regression analysis. RESULTS: In total, 265 physiotherapists participated in this survey study. Approximately 7% of physiotherapists reported using therapeutic VR for patients with chronic pain. On average, physiotherapists rated their overall experience with therapeutic VR at 7.0 and "whether they would recommend it" at 7.2, both on a 0-10 scale. Most physiotherapists (71%) who use therapeutic VR started using it less than two years ago and use it for a small proportion of their patients with chronic pain. Physiotherapists use therapeutic VR for a variety of conditions, including generalized (55%), neck (45%) and lumbar (37%) chronic pain. Physiotherapists use therapeutic VR mostly to reduce pain (68%), improve coordination (50%) and increase physical mobility (45%). Use of therapeutic VR was associated with a larger physiotherapy practice (OR = 2.38, 95% CI [1.14-4.98]). Unfamiliarity with VR seemed to be the primary reason for not using VR. DISCUSSION: Therapeutic VR for patients with chronic pain is in its infancy in Dutch primary care physiotherapy practice as only a small minority uses VR. Physiotherapists that use therapeutic VR are modestly positive about the technology, with large heterogeneity between treatment goals, methods of administering VR, proposed working mechanisms and chronic pain conditions to treat.

Effect of a Behavioral Therapy-Based Virtual Reality Application on Quality of Life in Chronic Low Back Pain.

OBJECTIVES: Low back pain is the leading cause of years lived with disability with a large impact on quality of life and resistance to a broad array of current treatments. This study aimed to investigate the effect of a novel self-administered behavioral therapy-based virtual reality (VR) application on the quality of life of patients with nonspecific chronic low back pain (CLBP). METHODS: A pilot randomized controlled trial was conducted in adults with nonspecific CLBP with moderate to severe pain, waiting for treatment in a teaching hospital-based pain clinic. The intervention group used a self-administered behavioral therapy-based VR application for at least 10 minutes daily for 4 weeks. The control group received standard care. The primary outcome was quality of life at 4 weeks measured by the short form-12 physical and mental scores. Secondary outcomes were daily worst and least pain, pain coping strategies, activities of daily living, positive health, anxiety, and depression. Discontinuation of therapy and adverse events were analyzed as well. RESULTS: Forty-one patients were included. One patient withdrew due to personal reasons. No significant treatment effect was found for the short form-12 physical score (mean difference: 2.6 points; 95% CI: -5.60 to 0.48) and mental score (-1.75; -6.04 to 2.53) at 4 weeks. There was a significant treatment effect for daily "worst pain score" ( F [1, 91.425] = 33.3, P < 0.001) and "least pain score" ( F [1, 30.069] = 11.5, P = 0.002). Three patients reported mild and temporary dizziness. DISCUSSION: Four weeks of self-administered VR for CLBP does not improve quality of life, however, it may positively affect daily pain experience.

Physiotherapy with integrated virtual reality for patients with complex chronic low back pain: protocol for a pragmatic cluster randomized controlled trial (VARIETY study).

BACKGROUND: Chronic low back pain (CLBP) is the most common chronic pain condition worldwide. Currently, primary care physiotherapy is one of the main treatment options, but effects of this treatment are small. Virtual Reality (VR) could be an adjunct to physiotherapy care, due to its multimodal features. The primary aim of this study is to assess the (cost-)effectiveness of physiotherapy with integrated multimodal VR for patients with complex CLBP, compared to usual primary physiotherapy care. METHODS: A multicenter, two-arm, cluster randomized controlled trial (RCT) including 120 patients with CLBP from 20 physiotherapists will be conducted. Patients in the control group will receive 12 weeks of usual primary physiotherapy care for CLBP. Patients in the experimental group will receive treatment consisting of 12 weeks of physiotherapy with integrated, immersive, multimodal, therapeutic VR. The therapeutic VR consists of the following modules: pain education, activation, relaxation and distraction. The primary outcome measure is physical functioning. Secondary outcome measures include pain intensity, pain-related fears, pain self-efficacy and economic measures. Effectiveness of the experimental intervention compared to the control intervention on primary and secondary outcome measures will be analyzed on an intention-to-treat principle, using linear mixed-model analyses. DISCUSSION: This pragmatic, multicenter cluster randomized controlled trial, will determine the clinical and cost-effectiveness of physiotherapy with integrated, personalized, multimodal, immersive VR in favor of usual physiotherapy care for patients with CLBP. TRIAL REGISTRATION: This study is prospectively registered at ClinicalTrials.gov (identifier: NCT05701891).

No evidence for stratified exercise therapy being cost-effective compared to usual exercise therapy in patients with knee osteoarthritis: Economic evaluation alongside cluster randomized controlled trial.

BACKGROUND: A stratified approach to exercise therapy may yield superior clinical and economic outcomes, given the large heterogeneity of individuals with knee osteoarthritis (OA). OBJECTIVE: To evaluate the cost-effectiveness during a 12-month follow-up of a model of stratified exercise therapy compared to usual exercise therapy in patients with knee OA, from a societal and healthcare perspective. METHODS: An economic evaluation was conducted alongside a cluster-randomized controlled trial in patients with knee OA (n = 335), comparing subgroup-specific exercise therapy for a 'high muscle strength subgroup', 'low muscle strength subgroup', and 'obesity subgroup' supplemented by a dietary intervention for the 'obesity subgroup' (experimental group), with usual ('non-stratified') exercise therapy (control group). Clinical outcomes included quality-adjusted life years - QALYs (EuroQol-5D-5 L), knee pain (Numerical Rating Scale) and physical functioning (Knee Injury and Osteoarthritis Outcome Score in daily living). Costs were measured by self-reported questionnaires at 3, 6, 9 and 12-month follow-up. Missing data were imputed using multiple imputation. Data were analyzed through linear regression. Bootstrapping techniques were applied to estimate statistical uncertainty. RESULTS: During 12-month follow-up, there were no significant between-group differences in clinical outcomes. The total societal costs of the experimental group were on average lower compared to the control group (mean [95% confidence interval]: € 405 [-1728, 918]), albeit with a high level of uncertainty. We found a negligible difference in QALYs between groups (mean [95% confidence interval]: 0.006 [-0.011, 0.023]). The probability of stratified exercise therapy being cost-effective compared to usual exercise therapy from the societal perspective was around 73%, regardless of the willingness-to-pay threshold. However, this probability decreased substantially to 50% (willingness-to-pay threshold of €20.000/QALY) when using the healthcare perspective. Similar results were found for knee pain and physical functioning. CONCLUSIONS: We found no clear evidence that stratified exercise therapy is likely to be cost-effective compared to usual exercise therapy in patients with knee OA. However, results should be interpreted with caution as the study power was lower than intended, due to the Coronavirus disease (COVID-19) pandemic.

Stratified exercise therapy does not improve outcomes compared with usual exercise therapy in people with knee osteoarthritis (OCTOPuS study): a cluster randomised trial.

QUESTION: In people with knee osteoarthritis, how much more effective is stratified exercise therapy that distinguishes three subgroups (high muscle strength subgroup, low muscle strength subgroup, obesity subgroup) in reducing knee pain and improving physical function than usual exercise therapy? DESIGN: Pragmatic cluster randomised controlled trial in a primary care setting. PARTICIPANTS: A total of 335 people with knee osteoarthritis: 153 in an experimental arm and 182 in a control arm. INTERVENTION: Physiotherapy practices were randomised into an experimental arm providing stratified exercise therapy (supplemented by a dietary intervention from a dietician for the obesity subgroup) or a control arm providing usual, non-stratified exercise therapy. OUTCOME MEASURES: Primary outcomes were knee pain severity (numerical rating scale for pain, 0 to 10) and physical function (Knee Injury and Osteoarthritis Outcome Score subscale activities of daily living, 0 to 100). Measurements were performed at baseline, 3 months (primary endpoint) and 6 and 12 months (follow-up). Intention-to-treat, multilevel, regression analysis was performed. RESULTS: Negligible differences were found between the experimental and control groups in knee pain (mean adjusted difference 0.2, 95% CI -0.4 to 0.7) and physical function (-0.8, 95% CI -4.3 to 2.6) at 3 months. Similar effects between groups were also found for each subgroup separately, as well as at other time points and for nearly all secondary outcome measures. CONCLUSION: This pragmatic trial demonstrated no added value regarding clinical outcomes of the model of stratified exercise therapy compared with usual exercise therapy. This could be attributed to the experimental arm therapists facing difficulty in effectively applying the model (especially in the obesity subgroup) and to elements of stratified exercise therapy possibly being applied in the control arm. REGISTRATION: Netherlands National Trial Register NL7463.

Construct validity of the OCTOPuS stratification algorithm for allocating patients with knee osteoarthritis into subgroups.

BACKGROUND: We recently developed a model of stratified exercise therapy, consisting of (i) a stratification algorithm allocating patients with knee osteoarthritis (OA) into one of the three subgroups ('high muscle strength subgroup' representing a post-traumatic phenotype, 'low muscle strength subgroup' representing an age-induced phenotype, and 'obesity subgroup' representing a metabolic phenotype) and (ii) subgroup-specific exercise therapy. In the present study, we aimed to test the construct validity of this algorithm. METHODS: Data from five studies (four exercise therapy trial cohorts and one cross-sectional cohort) were used to test the construct validity of our algorithm by 63 a priori formulated hypotheses regarding three research questions: (i) are the proportions of patients in each subgroup similar across cohorts? (15 hypotheses); (ii) are the characteristics of each of the subgroups in line with their proposed underlying phenotypes? (30 hypotheses); (iii) are the effects of usual exercise therapy in the 3 subgroups in line with the proposed effect sizes? (18 hypotheses). RESULTS: Baseline data from a total of 1211 patients with knee OA were analyzed for the first and second research question, and follow-up data from 584 patients who were part of an exercise therapy arm within a trial for the third research question. In total, the vast majority (73%) of the hypotheses were confirmed. Regarding our first research question, we found similar proportions in each of the three subgroups across cohorts, especially for three cohorts. Regarding our second research question, subgroup characteristics were almost completely in line with the proposed underlying phenotypes. Regarding our third research question, usual exercise therapy resulted in similar, medium to large effect sizes for knee pain and physical function for all three subgroups. CONCLUSION: We found mixed results regarding the construct validity of our stratification algorithm. On the one hand, it is a valid instrument to consistently allocate patients into subgroups that aligned our hypotheses. On the other hand, in contrast to our hypotheses, subgroups did not differ substantially in effects of usual exercise therapy. An ongoing trial will assess whether this algorithm accompanied by subgroup-specific exercise therapy improves clinical and economic outcomes.

Lack of Consensus Across Clinical Guidelines Regarding the Role of Psychosocial Factors Within Low Back Pain Care: A Systematic Review.

It is widely accepted that psychosocial prognostic factors should be addressed by clinicians in their assessment and management of patient suffering from low back pain (LBP). On the other hand, an overview is missing how these factors are addressed in clinical LBP guidelines. Therefore, our objective was to summarize and compare recommendations regarding the assessment and management of psychosocial prognostic factors for LBP chronicity, as reported in clinical LBP guidelines. We performed a systematic search of clinical LBP guidelines (PROSPERO registration number 154730). This search consisted of a combination of previously published systematic review articles and a new systematic search in medical or guideline-related databases. From the included guidelines, we extracted recommendations regarding the assessment and management of LBP which addressed psychosocial prognostic factors (ie, psychological factors ["yellow flags"], perceptions about the relationship between work and health, ["blue flags"], system or contextual obstacles ["black flags") and psychiatric symptoms ["orange flags"]). In addition, we evaluated the level or quality of evidence of these recommendations. In total, we included 15 guidelines. Psychosocial prognostic factors were addressed in 13 of 15 guidelines regarding their assessment and in 14 of 15 guidelines regarding their management. Recommendations addressing psychosocial factors almost exclusively concerned "yellow" or "black flags," and varied widely across guidelines. The supporting evidence was generally of very low quality. We conclude that in general, clinical LBP guidelines do not provide clinicians with clear instructions about how to incorporate psychosocial factors in LBP care and should be optimized in this respect. More specifically, clinical guidelines vary widely in whether and how they address psychosocial factors, and recommendations regarding these factors generally require better evidence support. This emphasizes a need for a stronger evidence-base underlying the role of psychosocial risk factors within LBP care, and a need for uniformity in methodology and terminology across guidelines. PERSPECTIVE: This systematic review summarized clinical guidelines on low back pain (LBP) on how they addressed the identification and management of psychosocial factors. This review revealed a large amount of variety across guidelines in whether and how psychosocial factors were addressed. Moreover, recommendations generally lacked details and were based on low quality evidence.

Stratified exercise therapy compared with usual care by physical therapists in patients with knee osteoarthritis: A randomized controlled trial protocol (OCTOPuS study).

OBJECTIVES: Knee osteoarthritis (OA) is characterized by its heterogeneity, with large differences in clinical characteristics between patients. Therefore, a stratified approach to exercise therapy, whereby patients are allocated to homogeneous subgroups and receive a stratified, subgroup-specific intervention, can be expected to optimize current clinical effects. Recently, we developed and pilot tested a model of stratified exercise therapy based on clinically relevant subgroups of knee OA patients that we previously identified. Based on the promising results, it is timely to evaluate the (cost-)effectiveness of stratified exercise therapy compared with usual, "nonstratified" exercise therapy. METHODS: A pragmatic cluster randomized controlled trial including economic and process evaluation, comparing stratified exercise therapy with usual care by physical therapists (PTs) in primary care, in a total of 408 patients with clinically diagnosed knee OA. Eligible physical therapy practices are randomized in a 1:2 ratio to provide the experimental (in 204 patients) or control intervention (in 204 patients), respectively. The experimental intervention is a model of stratified exercise therapy consisting of (a) a stratification algorithm that allocates patients to a "high muscle strength subgroup," "low muscle strength subgroup," or "obesity subgroup" and (b) subgroup-specific, protocolized exercise therapy (with an additional dietary intervention from a dietician for the obesity subgroup only). The control intervention will be usual best practice by PTs (i.e., nonstratified exercise therapy). Our primary outcome measures are knee pain severity (Numeric Rating Scale) and physical functioning (Knee Injury and Osteoarthritis Outcome Score subscale daily living). Measurements will be performed at baseline, 3-month (primary endpoint), 6-month (questionnaires only), and 12-month follow-up, with an additional cost questionnaire at 9 months. Intention-to-treat, multilevel, regression analysis comparing stratified versus usual care will be performed. CONCLUSION: This study will demonstrate whether stratified care provided by primary care PTs is effective and cost-effective compared with usual best practice from PTs.

Clinical Practice Guideline for Physical Therapy Assessment and Treatment in Patients With Nonspecific Neck Pain.

The Royal Dutch Society for Physical Therapy (KNGF) issued a clinical practice guideline for physical therapists that addresses the assessment and treatment of patients with nonspecific neck pain, including cervical radiculopathy, in Dutch primary care. Recommendations were based on a review of published systematic reviews.During the intake, the patient is screened for serious pathologies and corresponding patterns. Patients with cervical radiculopathy can be included or excluded through corresponding signs and symptoms and possibly diagnostic tests (Spurling test, traction/distraction test, and Upper Limb Tension Test). History taking is done to gather information about patients' limitations, course of pain, and prognostic factors (eg, coping style) and answers to health-related questions.In case of a normal recovery (treatment profile A), management should be hands-off, and patients should receive advice from the physical therapist and possibly some simple exercises to supplement "acting as usual."In case of a delayed/deviant recovery (treatment profile B), the physical therapist is advised to use, in addition to the recommendations for treatment profile A, forms of mobilization and/or manipulation in combination with exercise therapy. Other interventions may also be considered. The physical therapist is advised not to use dry needling, low-level laser, electrotherapy, ultrasound, traction, and/or a cervical collar.In case of a delayed/deviant recovery with clear and/or dominant psychosocial prognostic factors (treatment profile C), these factors should first be addressed by the physical therapist, when possible, or the patient should be referred to a specialist, when necessary.In case of neck pain grade III (treatment profile D), the therapy resembles that for profile B, but the use of a cervical collar for pain reduction may be considered. The advice is to use it sparingly: only for a short period per day and only for a few weeks.

Subgrouping and TargetEd Exercise pRogrammes for knee and hip OsteoArthritis (STEER OA): a systematic review update and individual participant data meta-analysis protocol.

INTRODUCTION: Knee and hip osteoarthritis (OA) is a leading cause of disability worldwide. Therapeutic exercise is a recommended core treatment for people with knee and hip OA, however, the observed effect sizes for reducing pain and improving physical function are small to moderate. This may be due to insufficient targeting of exercise to subgroups of people who are most likely to respond and/or suboptimal content of exercise programmes. This study aims to identify: (1) subgroups of people with knee and hip OA that do/do not respond to therapeutic exercise and to different types of exercise and (2) mediators of the effect of therapeutic exercise for reducing pain and improving physical function. This will enable optimal targeting and refining the content of future exercise interventions. METHODS AND ANALYSIS: Systematic review and individual participant data meta-analyses. A previous comprehensive systematic review will be updated to identify randomised controlled trials that compare the effects of therapeutic exercise for people with knee and hip OA on pain and physical function to a non-exercise control. Lead authors of eligible trials will be invited to share individual participant data. Trial-level and participant-level characteristics (for baseline variables and outcomes) of included studies will be summarised. Meta-analyses will use a two-stage approach, where effect estimates are obtained for each trial and then synthesised using a random effects model (to account for heterogeneity). All analyses will be on an intention-to-treat principle and all summary meta-analysis estimates will be reported as standardised mean differences with 95% CI. ETHICS AND DISSEMINATION: Research ethical or governance approval is exempt as no new data are being collected and no identifiable participant information will be shared. Findings will be disseminated via national and international conferences, publication in peer-reviewed journals and summaries posted on websites accessed by the public and clinicians. PROSPERO REGISTRATION NUMBER: CRD42017054049.

Analgesic use in patients with knee and/or hip osteoarthritis referred to an outpatient center: a cross-sectional study within the Amsterdam Osteoarthritis Cohort.

Although analgesics are widely recommended in current guidelines, underuse and inadequate prescription of analgesics seem to result in suboptimal treatment effects in patients with knee and/or hip osteoarthritis (OA). This study aimed (i) to describe the use of analgesics; and (ii) to determine factors that are related to analgesic use in patients with knee and/or hip OA referred to an outpatient center. A cross-sectional study with data from 656 patients with knee and/or hip OA referred to an outpatient center (Amsterdam Osteoarthritis (AMS-OA) cohort) was conducted. Self-reported use of analgesic (yes/no) was administered and subdivided into acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs, including coxibs) and opioids. Logistic regression analyses were performed to analyze the association between analgesic use and disease-related, predisposing and enabling factors. Analgesic use was reported by 63% of the patients, with acetaminophen, NSAIDs and opioid use reported by 50, 30 and 12%, respectively. Factors related to analgesic use were higher pain severity, longer duration of symptoms, higher radiographic hip OA severity, overweight/obesity and psychological distress. These factors explained 21% of the variance of analgesic use. More than one-third of patients with established knee and/or hip OA referred to an outpatient center did not use any analgesics. Although multiple, mostly disease-related associated factors were found, analgesic use remained predominantly unexplained. Our study seems to indicate that prescription of analgesics should be guided more dominantly by clinical symptoms and needs, and preceded by a thorough shared decision-making process between patient and physician.

Knee joint stabilization therapy in patients with osteoarthritis of the knee and knee instability: subgroup analyses in a randomized, controlled trial.

OBJECTIVE: To test whether knee stabilization therapy, prior to strength/functional training, may have added value in reducing activity limitations only in patients with knee osteoarthritis who have knee instability and (i) low upper leg muscle strength, (ii) impaired knee proprioception, (iii) high knee laxity, or (iv) frequent episodes of knee instability. DESIGN: Subgroup analyses in a randomized controlled trial comparing 2 exercise programmes (with/without knee stabilization therapy) (STABILITY; NTR1475). PATIENTS: Participants from the STABILITY-trial with clinical knee osteoarthritis and knee instability (n = 159). METHODS: Effect modification by upper leg muscle strength, knee proprioception, knee laxity, and patient-reported knee instability were determined using the interaction terms "treatment group subgroup factor", with the outcome measures WOMAC physical function (primary), numeric rating scale pain and the Get up and Go test (secondary). RESULTS: Effect modification by muscle strength was found for the primary outcome (p = 0.01), indicating that patients with greater muscle strength tend to benefit more from the experimental programme with additional knee stabilization training, while patients with lower muscle strength benefit more from the control programme. CONCLUSION: Knee stabilization therapy may have added value in patients with instability and strong muscles. Thus it may be beneficial if exercises target muscle strength prior to knee stabilization.

Osteoarthritis of the knee: multicompartmental or compartmental disease?

OBJECTIVE: Knee OA has been conceptualized as a multicompartmental disease, as a compartmental disease or as a combination of these two disease processes. The aim of this study was to determine the associations between four radiographic features (joint space narrowing, osteophyte formation, sclerosis and cysts) across and within the three knee compartments (medial tibiofemoral, lateral tibiofemoral and patellofemoral compartment) in knee OA. METHODS: Data from the Amsterdam OA Cohort were used. In 298 patients diagnosed with knee OA, radiographic features were examined in three knee joint compartments. Radiographic features were scored according to standardized scoring methods. Factor analysis was used to examine associations between the four radiographic features across and within compartments. RESULTS: A bifactor model showed a general multicompartmental factor: 10 of 12 radiographic features across the entire joint were associated with the general factor. The bifactor model also showed three compartmental factors-one for each compartment: joint space narrowing, sclerosis and to a lesser extent osteophyte formation were associated with these compartmental factors. CONCLUSION: These findings suggest a multicompartmental disease process in the knee, characterized by associations among features across the entire joint, as well as compartmental disease processes in each knee compartment, characterized by associations among features within specific compartments. Longitudinal studies are needed to explore the possibility of the development from a compartmental disease to a multicompartmental disease and the impact of contributing factors on the development.

Biomechanical factors and physical examination findings in osteoarthritis of the knee: associations with tissue abnormalities assessed by conventional radiography and high-resolution 3.0 Tesla magnetic resonance imaging.

INTRODUCTION: We aimed to explore the associations between knee osteoarthritis (OA)-related tissue abnormalities assessed by conventional radiography (CR) and by high-resolution 3.0 Tesla magnetic resonance imaging (MRI), as well as biomechanical factors and findings from physical examination in patients with knee OA. METHODS: This was an explorative cross-sectional study of 105 patients with knee OA. Index knees were imaged using CR and MRI. Multiple features from CR and MRI (cartilage, osteophytes, bone marrow lesions, effusion and synovitis) were related to biomechanical factors (quadriceps and hamstrings muscle strength, proprioceptive accuracy and varus-valgus laxity) and physical examination findings (bony tenderness, crepitus, bony enlargement and palpable warmth), using multivariable regression analyses. RESULTS: Quadriceps weakness was associated with cartilage integrity, effusion, synovitis (all detected by MRI) and CR-detected joint space narrowing. Knee joint laxity was associated with MRI-detected cartilage integrity, CR-detected joint space narrowing and osteophyte formation. Multiple tissue abnormalities including cartilage integrity, osteophytes and effusion, but only those detected by MRI, were found to be associated with physical examination findings such as crepitus. CONCLUSION: We observed clinically relevant findings, including a significant association between quadriceps weakness and both effusion and synovitis, detected by MRI. Inflammation was detected in over one-third of the participants, emphasizing the inflammatory component of OA and a possible important role for anti-inflammatory therapies in knee OA. In general, OA-related tissue abnormalities of the knee, even those detected by MRI, were found to be discordant with biomechanical and physical examination features.

Self-reported knee instability and activity limitations in patients with knee osteoarthritis: results of the Amsterdam osteoarthritis cohort.

The objective of this study was to evaluate whether self-reported knee instability is associated with activity limitations in patients with knee osteoarthritis (OA), in addition to knee pain and muscle strength. A cohort of 248 patients diagnosed with knee OA was examined. Self-reported knee instability was defined as the perception of any episode of buckling, shifting, or giving way of the knee in the past 3 months. Knee pain was assessed using a numeric rating scale, and knee extensor and flexor strength were measured using an isokinetic dynamometer. Activity limitations were measured by using the Western Ontario and McMasters Universities Osteoarthritis Index physical function questionnaire, the timed Get Up and Go, and the timed stair climbing and three questionnaires evaluating walking, climbing stairs, and rising from a chair. Other potential determinants of activity limitations were also collected, including joint proprioception, joint laxity, age, sex, body mass index (BMI), disease duration, and radiographic disease severity. Regression analyses evaluated the effect of adding self-reported knee instability to knee pain and muscle strength, when examining associations with the activity limitations measures. Self-reported knee instability was common (65 %) in this cohort of patients with knee OA. Analyses revealed that self-reported knee instability is significantly associated with activity limitations, even after controlling for knee pain and muscle strength. Joint proprioception, joint laxity, age, sex, BMI, duration of complaints, and radiographic severity did not confound the associations. In conclusion, self-reported knee instability is associated with activity limitations in patients with knee OA, in addition to knee pain and muscle strength. Clinically, self-reported knee instability should be assessed in addition to knee pain and muscle strength.

Association of lower muscle strength with self-reported knee instability in osteoarthritis of the knee: results from the Amsterdam Osteoarthritis cohort.

OBJECTIVE: To determine whether muscle strength, proprioceptive accuracy, and laxity are associated with self-reported knee instability in a large cohort of knee osteoarthritis (OA) patients, and to investigate whether muscle strength may compensate for impairment in proprioceptive accuracy or laxity, in order to maintain knee stability. METHODS: Data from 283 knee OA patients from the Amsterdam Osteoarthritis cohort were used. Univariable and multivariable logistic regression analyses were performed to assess the association between muscle strength, proprioceptive accuracy (motion sense), frontal plane varus-valgus laxity, and self-reported knee instability. Additionally, effect modification between muscle strength and proprioceptive accuracy and between muscle strength and laxity was determined. RESULTS: Self-reported knee instability was present in 67% of the knee OA patients and mainly occurred during walking. Lower muscle strength was significantly associated with the presence of self-reported knee instability, even after adjusting for relevant confounding. Impaired proprioceptive accuracy and high laxity were not associated with self-reported knee instability. No effect modification between muscle strength and proprioceptive accuracy or laxity was found. CONCLUSION: Lower muscle strength is strongly associated with self-reported knee instability in knee OA patients, while impairments in proprioceptive accuracy and laxity are not. A compensatory role of muscle strength for impaired proprioceptive accuracy or high laxity, in order to stabilize the knee, could not be demonstrated.