Changes in isokinetic trunk muscle strength and endurance after two different restoration programs in people with chronic low back pain: A longitudinal retrospective study.

Background: Multidisciplinary functional restoration programs (FRPs) aim to improve pain and function in people with chronic low back pain (CLBP). The intensity and content of FRPs varies; the benefits of one program over another are unclear. Objective: To assess changes in trunk muscle strength and endurance after an intensive (IFRP) (for people on sick leave for >6 months with high levels of fear-avoidance beliefs about physical activity and work) or semi-intensive (SIFRP) (for people working) FRP in people with CLBP. Methods: Longitudinal retrospective study from March 2016 to December 2019. Setting: rehabilitation department of a tertiary care center. Trunk flexor and extensor muscle strength (60°.s-1) and endurance (120°.s-1) were measured with the Humac NORM isokinetic dynamometer at pre and post FRP. Change in isokinetic variables (peak torque, total work and flexor/extensor ratio) after each program was assessed with a paired t-test (p < 0.05). Pearson's rho and multiple linear regression assessed associations between changes in isokinetic and clinical variables and demographic characteristics. Results: 125 individuals, 63.2 % female, age 43.5 (10.3) years, were included. Mean low back pain intensity was 49.8 (24.9) and 37.2 (25.8)/100 and mean activity limitation (QBPDS) was 38.8 (16.4) and 32.0 (14.6)/100 in the IFRP and SFRP groups, respectively. Trunk extensor peak torque, flexor total work, extensor total work and flexor/extensor peak ratio improved significantly in both FRPs, p < 0.001. The flexor/extensor total work ratio improved in the IFRP group only, p = 0.003. Trunk extensor endurance increased more in the IFRP than the SIFRP group, the absolute pre-post differences for extensor total work [95%CI] N.m were 611.7 [495.2; 728.3] in the IFRP group and 380.0 [300.8; 459.3] in the SIFRP group. No variables were correlated and none predicted improvement in extensor total work in either group. Conclusion: This study highlights the short-term independence of clinical and trunk muscle strength and endurance changes.

Oral resveratrol in adults with knee osteoarthritis: A randomized placebo-controlled trial (ARTHROL).

BACKGROUND: Resveratrol is a natural compound found in red wine. It has demonstrated anti-inflammatory properties in preclinical models. We compared the effect of oral resveratrol in a new patented formulation to oral placebo for individuals with painful knee osteoarthritis. METHODS AND FINDINGS: ARTHROL was a double-blind, randomized, placebo-controlled, Phase 3 trial conducted in 3 tertiary care centers in France. We recruited adults who fulfilled the 1986 American College of Rheumatology criteria for knee osteoarthritis and reported a pain intensity score of at least 40 on an 11-point numeric rating scale (NRS) in 10-point increments (0, no pain, to 100, maximal pain). Participants were randomly assigned (1:1) by using a computer-generated randomization list with permuted blocks of variable size (2, 4, or 6) to receive oral resveratrol (40 mg [2 caplets] twice a day for 1 week, then 20 mg [1 caplet] twice a day; resveratrol group) or matched oral placebo (placebo group) for 6 months. The primary outcome was the mean change from baseline in knee pain on a self-administered 11-point pain NRS at 3 months. The trial was registered at ClinicalTrials.gov: (NCT02905799). Between October 20, 2017 and November 8, 2021, we assessed 649 individuals for eligibility, and from November 9, 2017, we recruited 142 (22%) participants (mean age 61.4 years [standard deviation (SD) 9.6] and 101 [71%] women); 71 (50%) were randomly assigned to the resveratrol group and 71 (50%) to the placebo group. At baseline, the mean knee pain score was 56.2/100 (SD 13.5). At 3 months, the mean reduction in knee pain was -15.7 (95% confidence interval (CI), -21.1 to -10.3) in the resveratrol group and -15.2 (95% CI, -20.5 to -9.8) in the placebo group (absolute difference -0.6 [95% CI, -8.0 to 6.9]; p = 0.88). Serious adverse events (not related to the interventions) occurred in 3 (4%) in the resveratrol group and 2 (3%) in the placebo group. Our study has limitations in that it was underpowered and the effect size, estimated to be 0.55, was optimistically estimated. CONCLUSIONS: In this study, we observed that compared with placebo, oral resveratrol did not reduce knee pain in people with painful knee osteoarthritis. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT02905799.

Arthro-distension with early and intensive mobilization for shoulder adhesive capsulitis: A randomized controlled trial.

BACKGROUND: There are several therapeutic options for the management of shoulder adhesive capsulitis (AC). The superiority of arthro-distension over intra-articular steroid injection (ISI) for AC remains controversial. OBJECTIVES: To evaluate the efficacy of a single arthro-distension procedure combined with early and intensive mobilization (ADM) and physiotherapy, versus ISI and physiotherapy, in people with AC lasting ≥3 months. METHODS: This was a prospective, 2 parallel-group, 2-center, observer-blind randomized controlled trial conducted in tertiary care settings. Adults with AC were randomly assigned to the treatment or control group. Efficacy was assessed using the self-administered Shoulder Pain and Disability Index (SPADI). Total, pain and disability SPADI scores 15 days, 6 weeks, and 3, 6 and 12 months after the procedure (total SPADI at 15 days: primary outcome; other outcomes were secondary) were compared between groups using analysis of covariance (ANCOVA). A post hoc analysis stratified on the initial range of passive glenohumeral abduction, which had not been pre-specified, was conducted. RESULTS: There were 33 participants in each group. Both groups improved over time. Mean (SD) total SPADI score at 15 days was 33.8 (19.6) in the treatment group and 32.8 (17.5) in the control group, p = 0.393. There were no significant differences for any variables in the overall sample. The post hoc analysis found ADM to be associated with a significant decrease in total SPADI score at 15 days compared with ISI (p = 0.049) in individuals with initial passive glenohumeral abduction >45°. CONCLUSIONS: The effects of ADM on pain and function were not statistically different from those of ISI. However, ADM may be useful in individuals with initial passive glenohumeral abduction >45°. DATABASE REGISTRATION: NCT00724113.

Genicular artery embolization for knee osteoarthritis: Results of the LipioJoint-1 trial.

PURPOSE: The purpose of this study was to evaluate the safety and efficacy of transient genicular artery embolization (GAE) using an ethiodized oil-based emulsion for the treatment of knee osteoarthritis (KOA). MATERIALS AND METHODS: This prospective, single-arm, open-label, multicenter, first-in-human cohort trial was registered on ClinicalTrials.gov (NCT04733092). The main inclusion criterion was diagnosis of KOA according to a visual analogue scale (VAS) pain score ≥ 40 mm (score range: 0-100 mm), despite conservative treatment for at least three months. Treatment efficacy was assessed using changes in VAS pain score, Mean Western Ontario & McMaster Universities osteoarthritis (WOMAC) function score (normalized to 100; score ranging from 0 to100) and outcome measures in rheumatoid arthritis clinical trials (OMERACT)-Osteoarthritis Research Society (OARSI) set of responder criteria. RESULTS: Twenty-two consecutive participants (13 women; mean age, 66 ± 9 [standard deviation (SD)]) were included and underwent GAE. Emulsion consisted in a mixture of ioversol and ethiodized oil (ratio 1:3, respectively) prepared extemporaneously. The rate of serious adverse events attributed to GAE within one month was 5% (1/22), corresponding to reversible worsening of renal function. Immediate technical success rate was 100%. Mean VAS pain score dropped from 74.4 ± 16.5 (SD) mm at baseline to 37.2 ± 26.7 (SD) mm at three months (P < 0.001). Mean WOMAC function score (normalized to 100: score ranging from 0 to 100) decreased from 57.3 ± 17.1 (SD) at baseline to 33.5 ± 25.9 (SD) at three months (P < 0.001). At three months, 16 out of 22 participants (73%) were considered responders according to the OMERACT-OARSI set of responder criteria, including high improvement in either pain or WOMAC function, or improvement in both pain and WOMAC function. CONCLUSION: GAE using an ethiodized oil-based emulsion is safe and improves pain and function in participants with KOA for at least three months.

Early shoulder-girdle MRI findings in severe COVID-19-related intensive care unit-acquired weakness: a prospective cohort study.

OBJECTIVE: To describe clinical and early shoulder-girdle MR imaging findings in severe COVID-19-related intensive care unit-acquired weakness (ICU-AW) after ICU discharge. METHODS: A single-center prospective cohort study of all consecutive patients with COVID-19-related ICU-AW from November 2020 to June 2021. All patients underwent similar clinical evaluations and shoulder-girdle MRI within the first month and then 3 months (± 1 month) after ICU discharge. RESULTS: We included 25 patients (14 males; mean [SD] age 62.4 [12.5]). Within the first month after ICU discharge, all patients showed severe proximal predominant bilateral muscular weakness (mean Medical Research Council total score = 46.5/60 [10.1]) associated with bilateral, peripheral muscular edema-like MRI signals of the shoulder girdle in 23/25 (92%) patients. At 3 months, 21/25 (84%) patients showed complete or quasi-complete resolution of proximal muscular weakness (mean Medical Research Council total score > 48/60) and 23/25 (92%) complete resolution of MRI signals of the shoulder girdle, but 12/20 (60%) patients experienced shoulder pain and/or shoulder dysfunction. CONCLUSIONS: Early shoulder-girdle MRI findings in COVID-19-related ICU-AW included muscular edema-like peripheral signal intensities, without fatty muscle involution or muscle necrosis, with favorable evolution at 3 months. Precocious MRI can help clinicians distinguish critical illness myopathy from alternative, more severe diagnoses and can be useful in the care of patients discharged from intensive care with ICU-AW. KEY POINTS: • We describe the clinical and shoulder-girdle MRI findings of COVID-19-related severe intensive care unit-acquired weakness. • This information can be used by clinicians to achieve a nearly specific diagnosis, distinguish alternative diagnoses, assess functional prognosis, and select the more appropriate health care rehabilitation and shoulder impairment treatment.

Differences in Disability Perception in Systemic Sclerosis: A Mirror Survey of Patients and Health Care Providers.

Differences in disability perception between patients and care providers may impact outcomes. We aimed to explore differences in disability perception between patients and care providers in systemic sclerosis (SSc). We conducted a cross-sectional internet-based mirror survey. SSc patients participating in the online SPIN Cohort and care providers affiliated with 15 scientific societies were surveyed using the Cochin Scleroderma International Classification of Functioning, Disability and Health (ICF)-65 questionnaire, including 65 items (from 0 to 10), representing 9 domains of disability. Mean differences between patients and care providers were calculated. Care providers' characteristics associated with a mean difference ≥ 2 of 10 points were assessed in multivariate analysis. Answers were analyzed for 109 patients and 105 care providers. The mean age of patients was 55.9 (14.7) years and the disease duration was 10.1 (7.5) years. For all domains of the ICF-65, care providers' rates were higher than those of patients. The mean difference was 2.4 (1.0) of 10 points. Care providers' characteristics associated with this difference were organ-based specialty (OR = 7.0 [2.3-21.2]), younger age (OR = 2.7 [1.0-7.1]) and following patients with disease duration ≥5 years (OR = 3.0 [1.1-8.7]). We found systematic differences in disability perception between patients and care providers in SSc.

Chronic Low Back Pain: A Narrative Review of Recent International Guidelines for Diagnosis and Conservative Treatment.

Chronic low back pain (cLBP) is a public and occupational health problem that is a major professional, economic and social burden. We aimed to provide a critical overview of current international recommendations regarding the management of non-specific cLBP. We conducted a narrative review of international guidelines for the diagnosis and conservative treatment of people with non-specific cLBP. Our literature search yielded five reviews of guidelines published between 2018 and 2021. In these five reviews, we identified eight international guidelines that fulfilled our selection criteria. We added the 2021 French guidelines into our analysis. Regarding diagnosis, most international guidelines recommend searching for so-called yellow, blue and black flags, in order to stratify the risk of chronicity and/or persistent disability. The relevance of clinical examination and imaging are under debate. Regarding management, most international guidelines recommend non-pharmacological treatments, including exercise therapy, physical activity, physiotherapy and education; however, multidisciplinary rehabilitation, in selected cases, is the core treatment recommended for people with non-specific cLBP. Oral, topical or injected pharmacological treatments are under debate, and may be offered to selected and well-phenotyped patients. The diagnosis of people with cLBP may lack precision. All guidelines recommend multimodal management. In clinical practice, the management of individuals with non-specific cLBP should combine non-pharmacological and pharmacological treatments. Future research should focus on improving tailorization.

Barriers and facilitators to bracing in adults with painful degenerative scoliosis: a single-centred mixed-method feasibility study.

BACKGROUND: Conservative treatments including bracing and exercise therapy are prescribed on the first-line in adults with degenerative scoliosis. However, adherence to conservative treatments is low. We aimed to assess barriers and facilitators to bracing in adults with painful degenerative scoliosis. METHODS: We conducted a single-centred mixed-method pilot and feasibility study. All patients scheduled for a multidisciplinary custom-made bracing consultation, from July 2019 to January 2020, in a French tertiary care centre, were screened. Patients were eligible if they had painful adult degenerative scoliosis and a prescription for a rigid custom-made lumbar-sacral orthosis. The primary outcome was barriers and facilitators to bracing assessed by a qualitative approach using semi-structured interviews. Secondary outcomes were back pain, spine-specific activity limitations, symptoms of depression and satisfaction with bracing post-intervention assessed by a quantitative approach. RESULTS: Overall, 56 patients were screened and 14 (25%) were included. Mean age was 68.2 (12.3) years. Mean follow-up was 9.8 (2.0) months. Barriers to bracing were increased limitations in some activities, discomfort in hot weather and burden of aesthetic appearance. Facilitators to bracing were reduced pain, improved activities of daily living, suitable weight and improved spinal alignment. Participants self-implemented solutions to enhance adherence. The mean reduction from baseline in pain intensity was 1.7 (2.3) of 10 points, and 6 of 13 patients (46%) had pain intensity < 4 of 10 points. CONCLUSION: Bracing is a feasible intervention for people with painful adult degenerative scoliosis. Patients self-implemented their own solutions to enhance adherence.

Physical activity and low back pain: A critical narrative review.

BACKGROUND: Non-specific low back pain (LBP) is the leading cause of years lived with disability worldwide. Physical activity is an integral part of LBP treatment. OBJECTIVE: To critically review available evidence regarding the efficacy of physical activity for people with LBP. METHODS: Up to date critical narrative review of the efficacy of physical activity for the managment LBP. The process of article selection was unsystematic; articles were selected based on authors' expertise, self-knowledge and reflective practice. RESULTS: Therapeutic physical activity for LBP includes a wide range of non-specific and specific activities. The efficacy of physical activity on pain and activity limitations has been widely assessed. In acute and subacute LBP, exercise did not reduce pain compared to no exercise. In chronic low back pain (CLBP), exercise reduced pain at the earliest follow-up compared with no exercise. In a recent systematic review, exercise improved function both at the end of treatment and in the long-term compared with usual care. Exercice also reduced work disability in the long-term. We were unable to establish a clear hierarchy between different exercise modalities. Multidisciplinary functional programs consistently improved pain and function in the short- and long-term compared with usual care and physiotherapy and improved the long-term likelihood of returning to work compared to non-multidisciplinary programs. CONCLUSION: Physical activity of all types is an effective treatment for CLBP.

Impact of a multidisciplinary team meeting on patient-reported outcomes at 2 years after lumbar surgery: A prospective comparative exploratory study.

Failed back surgery syndrome is a challenge. We hypothesized that a multidisciplinary team meeting (MTM) may be useful to select patients who are the most likely to benefit from lumbar surgery. We conducted an observational, prospective, comparative, exploratory study. We aimed to compare core clinical patient-reported outcomes at 2 years after lumbar surgery between patients who attended a MTM and those who did not. Patients who underwent lumbar surgery for a degenerative disease, in a single academic orthopedic department, between January and September 2018, were consecutively screened. Eligible patients were surveyed between April and June 2020. Patient-reported outcomes included lumbar and radicular pain, spine-specific activity limitations and health-related quality of life assessed via self-administered questionnaires. Outcomes were compared between respondents who attended the MTM and those who did not. Overall, 211 patients underwent lumbar surgery, 108 were eligible and 44 included: 11 attended the MTM and 33 did not. Mean participants' age was 57.4 (15.4) years, symptom duration was 14.8 (15.3) months, lumbar pain was 51.3 (18.2) and radicular pain was 53.4 (18.6). At 2 years, we found no evidence that lumbar and radicular pain, activity limitations and health-related quality of life differed between the 2 groups. The decrease was -26.8 (41.1) versus -20.8 (30.4) in lumbar pain and -25.5 (43.0) versus -19.5 (27.5) in radicular pain, in participants who attended the MTM versus those who did not, respectively. We found no evidence that core clinical patient-reported outcomes at 2 years after lumbar surgery differed between participants who attended the MTM and those who did not. However, the exploratory design of our study does not allow concluding that MTMs do not have an impact.

Spine abnormalities associated with bone edema on sacroiliac joints MRI in patients with non-inflammatory chronic back pain.

OBJECTIVE: To investigate whether bone marrow edema (BME) fulfilling the ASAS definition of magnetic resonance imaging (MRI) sacroiliitis is associated with non-inflammatory spine abnormalities in patients with definite mechanical chronic back pain (CBP). METHODS: Patients with definite mechanical CBP, according to the physician, started before the age of 45 and be lasting for more than 3months but less than 3years underwent a protocolized MRI and radiographs of sacroiliac joint (SIJ) and spine. BME and structural changes were scored, by three readers, for SIJ as well as non-inflammatory abnormalities for spine, including degenerative lesions and static disorders. Univariate analysis by Chi2 test was performed to search a statistical association between BME fulfilling the ASAS definition of MRI sacroiliitis and the presence of at least one non-inflammatory spine abnormality. RESULTS: A total of 94 patients were analyzed, 27 (29%) patients had BME and 16 (17%) patients had BME fulfilling the ASAS definition of MRI sacroiliitis; 86 (91.5%) patients had at least one non-inflammatory spine abnormality which are associated into 3 distinct clusters. BME was slightly more frequent at the lower and posterior part of the SIJ. MRI sacroiliitis was associated with interspinous bursitis, facet joint effusion and lateral spinal deviation and was more likely in patients with at least one non-inflammatory spine abnormality (OR: 4.96, 95% CI [1.47; 16.72]). CONCLUSIONS: BME fulfilling the ASAS definition of MRI sacroiliitis is significantly associated with non-inflammatory spine abnormalities in patients with mechanical CBP.

Patient Acceptable Symptom State for Burden From Appearance Changes in People With Systemic Sclerosis: A Cross-sectional Survey.

OBJECTIVE: People with systemic sclerosis (SSc) often report substantial burden from appearance changes. We aimed to estimate the patient acceptable symptom state (PASS) for burden from appearance changes in people with SSc. METHODS: We conducted a secondary analysis of the SCISCIF II study, a cross-sectional survey of 113 patients with SSc from France enrolled in the Scleroderma Patient-centered Intervention Network Cohort. Burden from appearance changes was assessed with a self-administered numeric rating scale (0, no burden to 10, maximal burden). Acceptability of the symptom state was assessed with a specific anchoring question. Participants who answered yes were in the group of patients who considered their symptom state as acceptable. The PASS for the burden from appearance changes was estimated with the 75th percentile method. RESULTS: Assessments of burden from appearance changes and answers to the anchoring question were available in 82/113 (73%) participants from the SCISCIF II study. Median age was 55 (IQR 24) years, mean disease duration 9.6 (SD 6.5) years and 32/80 (40%) participants had diffuse cutaneous SSc. The PASS estimate for the burden from appearance changes was 4.8 (95% CI 1.0-7.0) of 10 points. CONCLUSION: Our study provides a PASS estimate for burden from appearance changes. Our estimate could serve as a binary response criterion to assess the efficacy of treatments targeting burden from appearance changes.

Effect of Prehabilitation Before Total Knee Replacement for Knee Osteoarthritis on Functional Outcomes: A Randomized Clinical Trial.

Importance: Multidisciplinary prehabilitation before total knee replacement (TKR) for osteoarthritis may improve outcomes in the postoperative period. Objective: To compare multidisciplinary prehabilitation with usual care before TKR for osteoarthritis in terms of functional independence and activity limitations after surgery. Design, Setting, and Participants: This prospective, open-label randomized clinical trial recruited participants 50 to 85 years of age with knee osteoarthritis according to the American College of Rheumatology criteria for whom a TKR was scheduled at 3 French tertiary care centers. Recruitment started on October 4, 2012, with follow-up completed on November 29, 2017. Statistical analyses were conducted from March 29, 2018, to March 6, 2019. Interventions: Four supervised sessions of multidisciplinary rehabilitation and education (2 sessions per week, at least 2 months before TKR, delivered to groups of 4-6 participants at each investigating center; session duration was 90 minutes and included 30 minutes of education followed by 60 minutes of exercise therapy) or usual care (information booklet and standard advice by the orthopedic surgeon) before TKR. Main Outcomes and Measures: The short-term primary end point was the proportion of participants achieving functional independence a mean (SD) of 4 (1) days after surgery defined as level 3 on the 4 functional tests. The midterm primary end point was activity limitations within 6 months after TKR assessed by the area under the receiver operating characteristic curve of the self-administered Western Ontario Questionnaire and McMaster Universities Osteoarthritis Index function subscale. Results: A total of 262 patients (mean [SD] age, 68.6 [8.0] years; 178 women [68%]) were randomized (131 to each group). A mean (SD) of 4 (1) days after surgery, 34 of 101 (34%) in the experimental group vs 26 of 95 (27%) in the control group achieved functional independence (risk ratio, 1.4; 97.5% CI, 0.9-2.1; P = .15). At 6 months, the mean (SD) area under the curve for the Western Ontario Questionnaire and McMaster Universities Osteoarthritis Index function subscale was 38.1 (16.5) mm2 in the experimental group vs 40.6 (17.8) mm2 in the control group (absolute difference, -2.8 mm2; 97.5% CI, -7.8 to 2.3; P = .31 after multiple imputation). No differences were found in secondary outcomes. Conclusions and Relevance: This randomized clinical trial found no evidence that multidisciplinary prehabilitation before TKR for osteoarthritis improves short-term functional independence or reduces midterm activity limitations after surgery. Trial registration: ClinicalTrials.gov Identifier: NCT01671917.

Determinants of apprehension to return to sport after reconstruction of the anterior cruciate ligament: an exploratory observational retrospective study.

BACKGROUND: Only 65% of people return to a level of sport equivalent to that before after anterior cruciate ligament (ACL) surgery. Persisting apprehension may in part explain this observation. We aimed to describe characteristics of people with ACL-Return to Sport after Injury (RSI) scores ≥ 60/100 (low apprehension) at 6 months after injury and to identify variables independently associated with low apprehension at 6 months. METHODS: We conducted a single-center retrospective study. People who had surgery for an ACL rupture and who participated in an outpatient post-operative rehabilitation program were included consecutively. The ACL-RSI questionnaire was self-administered at 6 months after injury. Baseline characteristics of people with ACL-RSI scores ≥ 60/100 and < 60/100 were described. Multiple logistic regression was performed to identify baseline variables associated with low apprehension at 6 months. RESULTS: We included 37 participants: 13/37 (35.1%) were women and mean age was 27.2 (9.2) years. At 6 months, 21/37 (56.8%) had an ACL-RSI score ≥ 60/100. Participants who had an ACL-RSI score ≥ 60/100 more often received a preoperative rehabilitation (16/21 [76.2%] vs 5/16 [31.2%]), and had less often knee pain (7/21 [33.3%] vs 7/16 [43.7%]) and effusion (5/21 [23.8%] vs 8/16 [50.0%]) at 1 month after surgery, than participants who had an ACL-RSI score < 60/100. In the multivariate analysis, preoperative rehabilitation was associated with low apprehension at 6 months (OR [95% CI] = 0.107 [0.023 to 0.488], p = 0.002). CONCLUSIONS: Preoperative rehabilitation was independently associated with low apprehension at 6 months. TRIAL REGISTRATION: Not applicable.

Patient acceptable symptom state for patient-reported outcomes in people with non-specific chronic low back pain.

BACKGROUND: The patient acceptable symptom state (PASS) is a treatment-response criterion developed to determine the clinical relevance of a treatment effect. Its estimates for some patient-reported outcomes (PROs) in non-specific chronic low back pain (cLBP) are lacking and the stability of PRO estimates between independent cLBP populations is unknown. We hypothesized that these PRO estimates will be stable. OBJECTIVES: To estimate and compare the PASS for PROs between 2 independent cLBP populations. METHODS: We conducted a secondary analysis of a randomized controlled trial (PREDID) and a cohort of outpatients with non-specific cLBP. Using an anchoring question, participants who self-rated their health as "excellent", "very good" or "good" at 1 month were considered to have an acceptable symptom state. PASS estimates for 5 PROs were calculated by using the 75th percentile method. Estimates were compared between the 2 populations with bootstrap resampling. RESULTS: A total of 256 participants with non-specific cLBP were included: 135 patients with cLBP and active discopathy from the PREDID trial and 121 outpatients with cLBP without active discopathy followed up in an independent cohort. Overall, 137/256 (54%) participants had an acceptable symptom state at 1 month. PASS estimates were 47.5 (95% confidence interval [CI] 40.0 to 50.0)/100 for lumbar pain (0, no pain and 100, maximal pain), 30.5 (30.0 to 40.0)/100 for radicular pain, 39.3 (33.6 to 45.3)/100 for Quebec Back Pain Disability score (0, no disability and 100, maximal disability), 10.0 (9.2 to 10.0)/21 for the Hospital Anxiety Depression anxiety subscale (0, no anxiety, and 21, maximal anxiety) and 6.7 (6.0 to 8.0)/21 for the depression subscale (0, no depression, and 21, maximal depression). PASS estimates did not differ between the 2 populations. CONCLUSIONS: Our study provides PASS estimates for 5 PROs commonly used in cLBP. Our estimates were stable between 2 independent populations of people with cLBP. The stability of our PASS estimates suggests that they are relevant for interpreting PRO values in clinical trials and practice. ClinicalTrials.gov no. (PREDID trial) NCT00804531.