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The article presents a study on the quantification of buprenorphine-glucuronide (BUP-G) and norbuprenorphine-glucuronide (NBUP-G) in human urine through a liquid chromatography-tandem mass spectrometry (LC-MS-MS). The procedure of the study covers a dilution step, filtration using a Mini-Uniprep Filter, and direct injection in the LC area. Results demonstrated the specificity of the LC-MS-MS method for the detection of BUP-G and NBUP-G in the body fluid.

Background: Musculoskeletal pain has a high prevalence in adolescence and causes huge consequences for the individuals and the society. Little knowledge exists on social risk factors for musculoskeletal pain in adolescents. This study aimed to investigate if low social acceptance among peers during the first year of upper secondary school was associated with persistent and severe persistent musculoskeletal pain 2 years later and if psychological distress modified this association.Methods: Longitudinal data from the Norwegian Fit Futures Study was used. Students in the first year of upper secondary school answered an electronic questionnaire, covering health status, pain, social acceptance among peers, and psychological distress. Persistent musculoskeletal pain was measured 2 years later. Multiple logistic regression analyses and moderation analyses were conducted adjusting for sex and chronic diseases. Main analyses were conducted on participants without persistent musculoskeletal pain at baseline, and secondary analyses were conducted on all participants with and without persistent musculoskeletal pain at baseline.Results: Of 775 participants (52% females), 556 (71.7%) were pain-free at baseline and included in the main analyses. Significant associations between low social acceptance among peers and persistent musculoskeletal pain 2 years later were found in crude (Odds ratio (OR) = 1.8, 95%CI [1.0-3.1]) and adjusted analyses (OR = 1.8, 95%CI [1.0-3.2]). No statistically significant effect modification of psychological distress (p = 0.89) on this association was found. A significant association between low social acceptance and persistent musculoskeletal pain was found in adjusted secondary analyses of all the students (n = 692) (OR = 1.6, 95%CI [1.0-2.3]).Conclusions: Our results indicate that low social acceptance among peers increases the risk of future persistent musculoskeletal pain in adolescents. Thus, interventions strengthening adolescent's social arenas may be helpful to prevent persistent musculoskeletal pain.Trial Registration: Retrospective registered at clinicaltrials.org NCT04526522 . [ABSTRACT FROM AUTHOR]

The effects of dissolved oxygen (DO) concentration combined with sublethal doses of ammonia on growth and food conversion efficiency (FCE) were investigated in juvenile spotted wolffish. Fish with a mean (S.D.) initial weight of 95.4 (18.0) g were reared in shallow raceways (initial stocking density 10 kg m−2) at normoxic (9.6 mg l−1) and hyperoxic (14.5 mg l−1) conditions, and also under both normoxia and hyperoxia with an additional sublethal concentration of unionised ammonia (0.17 mg NH3 l−1) added, for 8 weeks at 8 °C. There was an interacting effect of oxygen saturation and ammonia level on growth, as growth rate was significantly higher in the hyperoxic/NH3 group compared to the normoxic/NH3 group (P<0.001), suggesting that hyperoxic conditions may increase tolerance to unionised ammonia in spotted wolffish. At the end of the experiment, no difference in mean weight was found between fish reared at normoxic and hyperoxic conditions without added ammonia, whereas mean weight was reduced under normoxia with added ammonia as compared to normoxia without added ammonia. Mean daily oxygen consumption was investigated in the non-ammonia groups at both normoxic and hyperoxic conditions, and O2 consumption was significantly higher (P<0.001) under hyperoxic (100.5 mg O2 kg−1 h−1) compared to normoxic (79.9 mg O2 kg−1 h−1) conditions. A clear diurnal rhythm in the O2 consumption pattern was seen at both O2 saturations, with the most striking observation being a dramatic increase in the morning when the light was turned on. Overall, our results support earlier findings of a high capacity to adapt to variations in environmental water quality parameters, and to restore normal growth rate in the spotted wolffish. [Copyright &y& Elsevier]

The objective was to investigate risk factors and risk profiles associated with neck pain in young adults using longitudinal data from the North-Trøndelag Health Study (HUNT). Risk factors were collected from adolescents (13–19 years of age), and neck pain was measured 11 years later. The sample was divided into two: Sample I included all participants (n = 1433), and Sample II (n = 832) included only participants who reported no neck/shoulder pain in adolescence. In multiple regression analyses in Sample I, female sex (OR = 1.9, 95% CI [1.3–2.9]), low physical activity level (OR = 1.6, 95% CI [1.0–2.5]), loneliness (OR = 2.0, 95% CI [1.2–3.5]), headache/migraine (OR = 1.7, 95% CI [1.2–2.6]), back pain (OR = 1.5, 95% CI [1.0–2.4]) and neck/shoulder pain (OR = 2.0, 95% [CI 1.3–3.0]) were associated with neck pain at the 11-year follow-up. Those with a risk profile including all these risk factors had the highest probability of neck pain of 67% in girls and 50% in boys. In Sample II, multiple regression analyses revealed that female sex (OR = 2.2, 95% CI [1.3–3.7]) and perceived low family income (OR = 2.4, 95% CI [1.1–5.1]) were associated with neck pain at the 11-year follow-up. Girls and boys with a perceived low family income had a 29% and 17% higher probability of neck pain than adolescents with a perceived high family income. The risk profiles in both samples showed that co-occurrence of risk factors, such as headache/migraine, neck/shoulder pain, back pain, low physical activity level, loneliness, and perceived low family income cumulatively increased the probability of neck pain in young adulthood. These results underline the importance of taking a broad perspective when studying, treating, and preventing neck pain in adolescents. [ABSTRACT FROM AUTHOR]

In this work, we investigated for the first time hydrophobic deep eutectic solvents (DES) as supported liquid membrane (SLM) for electromembrane extraction (EME). Camphor, coumarin, DL-menthol, and thymol were used as non-ionic DES components. Different DESs compositions were tested, to study systematically the importance of hydrogen bonding and dispersion/aromatic interactions during mass transfer across the SLM. Unexpectedly, mixtures of coumarin and thymol were highly efficient SLMs, and provided exhaustive or near-exhaustive extraction of non-polar bases, non-polar acids, and polar bases. SLMs with such performance for both bases and acids, in a large polarity window, are not found in current literature. The SLMs were highly aromatic, very strong hydrogen bonding donors, and moderately strong hydrogen bonding acceptors. Aromatic (π type) interactions were apparently very important for transfer of bases, while hydrogen bonding were dominant for acids. EME of six polar basic drugs from plasma, with a coumarin and thymol mixture as SLM, and combined with UHPLC-MS/MS analysis, was evaluated to test the potential for analytical applications. Plasma was diluted 1:1 with phosphate buffer pH 2.0. Calibration curves were linear in the therapeutic ranges (0.970 < R2 < 0.999), recoveries ranged between 47 and 93%, and repeatability was within 1.6–10.7% RSD. The clean-up efficiency was excellent and no matrix effects from plasma were seen. Presence of trace levels of coumarin in the acceptor phase was however found to cause some ion enhancement. Based on the current work, we foresee more research on the use of DES in EME. Image 1 • Natural deep eutectic solvents were used as SLM for EME for the first time. • Coumarin and thymol-based SLMs were efficient for extraction most compounds. • High extraction recoveries with good repeatability were obtained from human plasma. [ABSTRACT FROM AUTHOR]

The use of designer benzodiazepines appears to be increasing in many countries, but data concerning blood concentrations are scarce, making interpretation of concentrations difficult. The aim of this study was to report blood concentrations of clonazolam, diclazepam, etizolam, flualprazolam, flubromazepam, flubromazolam and phenazepam and to investigate the relationship between blood concentrations and impairment. The concentration data are from blood samples collected from living cases (apprehended drivers and other drug offences) and medico-legal autopsies. The blood samples were analysed for the seven designer benzodiazepines mentioned above by ultra high performance liquid chromatography–tandem mass spectrometry. Positive cases from between 1 June 2016 and 30 September 2019 were included. Blood concentrations and the conclusion from a clinical test of impairment (when available) are reported. The presented seven benzodiazepines were detected in a total of 575 cases, where 554 of these cases concerned apprehended drivers or other criminal offenders. The number of findings and the median (range) concentrations were as follows: clonazolam, n  = 22, 0.0041 mg/L (0.0017–0.053 mg/L); diclazepam, n  = 334, 0.0096 mg/L (0.0016–0.25 mg/L); etizolam, n  = 40, 0.054 mg/L (0.015–0.30 mg/L); flualprazolam, n  = 10, 0.0080 mg/L (0.0033–0.056 mg/L); flubromazepam, n  = 5, 0.037 mg/L (0.0070–0.70 mg/L); flubromazolam, n  = 20, 0.0056 mg/L (0.0004–0.036 mg/L); and phenazepam, n  = 138, 0.022 mg/L (0.0018–0.85 mg/L). A designer benzodiazepine was the only drug detected with relevance for impairment in 25 of the 554 living cases. The physician concluded with impairment in 19 of the 25 cases. Most of the concentrations in these cases were relatively similar to or higher than the median reported concentrations. The most frequent other drugs detected were amphetamine, tetrahydrocannabinol, clonazepam and methamphetamine. The presented blood concentrations can be helpful with the interpretation of cases involving one or more of these seven benzodiazepines. The results indicate that concentrations commonly observed in forensic cases are associated with impairment. [ABSTRACT FROM AUTHOR]

Background: Young adulthood is a sensitive period of life where development of musculoskeletal neck pain may be established and impact future health. The objective of this systematic review was to investigate risk factors for non-specific neck pain in young adults.Methods: Systematic searches were conducted in six databases in September 2019. Prospective cohorts and registry studies including participants in whom the risk factor or the outcome (neck pain) was registered in the ages 18-29 years old were included. The Quality in Prognosis Studies tool was used for quality assessment. A modification of the Grading of Recommendations Assessments, Development and Evaluation was used to assess the overall quality of the evidence. Potential risk factors investigated in more than one study were summarised.Results: Searches yielded 4527 articles, of which six matched the eligibility criteria. Fifty-six potential risk factors were investigated in the six studies, covering a broad range of domains. Five risk factors were investigated in more than one study (female sex, body mass index (BMI), physical activity, duration of computer use and perceived stress). Physical activity and BMI showed no association with neck pain, and inconsistent results were found for female sex, duration of daily computer use and perceived stress. Risk of bias was moderate or high in all studies, and the overall quality of evidence was very low.Conclusion: The studies included many potential risk factors, but none of them showed consistent associations with neck pain. There is a paucity of high-quality studies investigating risk factors for neck pain in young adults. [ABSTRACT FROM AUTHOR]

Data from previous experimental studies on the detection time of oxazepam and zopiclone in biological matrices are limited. The aim of this study was to examine the detection time in urine and oral fluid after single oral doses of oxazepam and zopiclone. Ten healthy volunteers received 25 mg of oxazepam in the evening of Day 1 and 7.5 mg of zopiclone in the evening of Day 3. Urine and oral fluid samples were collected twice daily for 9 days, with an additional sampling the day after ingestion of zopiclone. A total of 19 samples of both urine and oral fluid from each participant were analyzed using fully validated chromatographic methods. The median detection time for oxazepam was 91 h (range 73–108) in urine and 67 h (range 50–98) in oral fluid. The median detection time for zopiclone in urine was 49 h (range 25–98) and 59 h (range 48–146) in oral fluid. The metabolite zopiclone N-oxide showed a detection time of 36 h (range 25–84) in urine. The area under the concentration–time curve (AUCTotal) in urine corrected for creatinine was 150 μmol/L/mmol/L*h (range 105–216) for oxazepam and 1.60 μmol/L/mmol/L*h (range 0.79–4.53) for zopiclone. In oral fluid, the AUCtotal was 673 nmol/L*h (range 339–1,316) for oxazepam and 2,150 nmol/L*h (range 493–4,240) for zopiclone. In conclusion, oxazepam can be detected longer in urine than in oral fluid, while zopiclone can be detected longer in oral fluid than in urine. The high AUCTotal for zopiclone in oral fluid shows that the transfer into oral fluid is significant. In certain individuals the detection time of zopiclone in oral fluid is long. These results can be helpful when interpreting drug testing analyzes. [ABSTRACT FROM AUTHOR]

Benzodiazepines are commonly seen in samples submitted for drug testing of patients, people involved in child welfare cases, work-place drug testing, as well as in drug-facilitated assaults. Limited previous experimental studies are available regarding the excretion of benzodiazepines in urine and oral fluid. The aim of this study was to investigate the concentrations of diazepam and alprazolam in oral fluid and urine for up to 2 weeks after ingestion of a single oral dose in healthy volunteers. A total of 11 healthy volunteers ingested 10 mg diazepam at the start of the study and 0.5 mg alprazolam on Day 3 of the study. A total number of 10 oral fluid samples and 17 urine samples were collected from each participant. The samples were analyzed by liquid chromatography with tandem mass spectroscopy and ultra-high performance liquid chromatography tandem mass spectrometry methods. The median detection time was 252 h for the longest detected diazepam metabolite in urine (oxazepam, range 203–322) and 132 h in oral fluid (N -desmethyldiazepam, range 109–136). For alprazolam, the median detection time was 36 h (metabolite α-OH-alprazolam, range 26–61) in urine and 26 h (alprazolam, range 4–37) in oral fluid. These results show that detection times are only 36 h for alprazolam in urine after intake of a single therapeutic oral dose. For diazepam in urine, detection times were 11 days. Detection times were generally shorter in oral fluid compared to urine. The results could be helpful in the interpretation of diazepam or alprazolam findings in drug testing cases involving urine or oral fluid. [ABSTRACT FROM AUTHOR]

A novel ion pair reversed phase ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC–MS/MS) method for simultaneous determination of the stress hormones adrenaline, noradrenaline and corticosterone in rodent blood was developed and fully validated. Separations were performed on an Acquity HSS T3 column (2.1 mm i.d. × 100 mm, 1.8 μm) with gradient elution and a runtime of 5.5 min. The retention of adrenaline and noradrenaline was substantially increased by employing the ion pair reagent heptafluorobutyric acid (HFBA). Ion pair reagents are usually added to the mobile phase only, but we demonstrate for the first time that including HFBA to the sample reconstitution solvent as well, has a major impact on the chromatography of these compounds. The stability of adrenaline and corticosterone in rodent blood was investigated using the surrogate analytes adrenaline-d 3 and corticosterone-d 8 . The applicability of the described method was demonstrated by measuring the concentration of stress hormones in rodent blood samples. [ABSTRACT FROM AUTHOR]

Parallel artificial liquid membrane extraction (PALME) was combined with ultra-high performance liquid chromatography-mass spectrometry (UHPLC–MS) and the potential for screening of new psychoactive substances (NPS) was investigated for the first time. PALME was performed in 96-well format comprising a donor plate, a supported liquid membrane (SLM), and an acceptor plate. Uncharged NPS were extracted from plasma or whole blood, across an organic SLM, and into an aqueous acceptor solution, facilitated by a pH gradient. MDAI (5,6-methylenedioxy-2-aminoindane), methylone, PFA (para-fluoroamphetamine), mCPP (meta-chlorophenylpiperazine), pentedrone, methoxetamine, MDPV (methylenedioxypyrovalerone), ethylphenidate, 2C-E (2,5-dimethoxy-4-ethylphenethylamine), bromo-dragonfly, and AH-7921 (3,4-dichloro- N -{[1-(dimethylamino)cyclohexyl]methyl}benzamide) were selected as representative NPS. Optimization of operational parameters was necessary as the NPS were novel to PALME, and because PALME was performed from whole blood for the very first time. In the PALME method developed for plasma, NPS were extracted from a 250 μL alkalized donor solution consisting of 125 μL plasma sample, 115 μL 40 mM NaOH, and 10 μL internal standard. In the PALME method from whole blood, the 250 μL alkalized donor solution consisted of 100 μL whole blood, 50 μL deionized water, 75 μL 80 mM NaOH, and 25 μL internal standard. In both methods, extraction was accomplished across an SLM of 5 μL dodecyl acetate with 1% trioctylamine (w/w), and further into an acidic acceptor solution of 50 μL 20 mM formic acid. The extraction was promoted by agitation at 900 rpm and was carried out for 120 min. Method validation was performed and the following parameters were considered: linearity, limits of quantification (LOQ), intra- and inter-day precision, accuracy, extraction recoveries, carry-over, and matrix effects. The validation results were in accordance with FDA guidelines. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate psychoactive drug use among nightclub patrons by analysing samples of oral fluid and compare with findings in blood samples from criminal suspects. We hypothesized that the profile of illicit drug use among nightclub patrons is different from what we observe in those forensic cases. Research stations were established outside nine popular nightclubs with different profiles and patron-characteristics in downtown Oslo. Data and sample collection was conducted on Fridays and Saturdays in March and May 2014. Individuals and groups who entered defined recruitment zones from 23:00 to 03:30 were invited to participate in this voluntary and anonymous study. Oral fluid was collected using the Intercept Oral Fluid Sampling Device. Methanol was added to increase the recovery of cannabinoids from the device. Sample preparation was performed using liquid-liquid extraction with ethyl acetate/heptane (4:1) after adding internal standards, ammonium carbonate buffer pH 9.3 and Triton X100. The first 80 samples were analysed for 122 substances, which included psychoactive medicinal drugs, classical illicit drugs and new psychoactive substances (NPS). Based on the findings and discussions with police and customs authorities, the remaining oral fluid samples were analysed for 46 substances. Among the 500 samples collected during the study period, we found illicit drugs in 25.4% and medicinal drugs in 4.2% of the samples. The most prevalent substances were: cocaine 14.6%, THC 12.4%, amphetamine/methamphetamine 2.8%, diazepam 1.2% and clonazepam 1.0%. Various NPS were found in 1.4% of the samples. The prevalence of drugs in blood samples from criminal suspects were for cocaine 3.4%, THC 34.7%, amphetamine/methamphetamine 37.0%, diazepam 12.0%, and clonazepam 29.3%. Multi-drug use was more common among criminal suspects (41.3%) than among club patrons (6.8%). The results showed that the drug use pattern among nightclub patrons was substantially different from the drug use pattern manifested by individuals apprehended by the police suspected for criminal conduct. [ABSTRACT FROM AUTHOR]

Investigating how individual characteristics modify treatment effects can improve understanding, interpretation, and translation of trial findings. The purpose of this secondary analysis was to identify treatment effect modifiers of the MI-NAV trial, a 3 arm, parallel randomized controlled trial which compared motivational interviewing and stratified vocational advice intervention in addition to usual case management (UC), to UC alone. This study included (n = 514) participants with musculoskeletal disorders on sick leave for at least 50% of their contracted work hours for at least 7 consecutive weeks with the Norwegian Labour and Welfare Administration. Sickness absence days was the primary outcome, measured from baseline assessment date until the 6-month follow-up. Potential treatment effect modifiers, identified a priori and informed by expert consultation and literature, were evaluated using linear regression models and statistical interaction tests. For motivational interviewing versus UC, age (mean difference [MD] -.7, 95% confidence interval [CI] -1.5 to .2; P = .13) and self-perceived health status (MD -.3, 95% CI -.7 to .1; P = .19) were identified as potential effect modifiers (P ≤ .2). For stratified vocational advice intervention versus UC, analgesic medication use (MD -26.2, 95% CI -45.7 to -6.7; P = .009) was identified as a treatment effect modifier (P ≤ .05). These findings may assist in more targeted treatment adaptation and translation as well as the planning of future clinical trials. PERSPECTIVE: This secondary analysis of the MI-NAV trial found that analgesic medication use, age, and self-perceived health may modify the effect of 2 vocational interventions on reducing sickness absence in people with musculoskeletal disorders., (Copyright © 2024 United States Association for the Study of Pain, Inc. Published by Elsevier Inc. All rights reserved.)

Objectives: To evaluate the 1-year cost-effectiveness of strength exercise or aerobic exercise compared with usual care for patients with symptomatic knee osteoarthritis (OA), from a societal and healthcare perspective., Design: Cost-effectiveness analysis embedded in a three-arm randomised controlled trial., Participants and Setting: A total of 161 people with symptomatic knee OA seeking Norwegian primary or secondary care were included in the analyses., Interventions: Participants were randomised to either 12 weeks of strength exercise (n=54), 12 weeks of aerobic exercise (n=53) or usual care (n=54)., Outcome Measures: Quality-adjusted life-years (QALYs) estimated by the EuroQol-5 Dimensions-5 Levels, and costs related to healthcare utilisation and productivity loss estimated in euros (€), aggregated for 1 year of follow-up. Cost-effectiveness was expressed with mean incremental cost-effectiveness ratios (ICERs). Bootstrapping was used to estimate ICER uncertainty., Results: From a 1-year societal perspective, the mean cost per patient was €7954, €8101 and €17 398 in the strength exercise, aerobic exercise and usual care group, respectively. From a 1-year healthcare perspective, the mean cost per patient was €848, €2003 and €1654 in the strength exercise, aerobic exercise and usual care group, respectively. Mean differences in costs significantly favoured strength exercise and aerobic exercise from a 1-year societal perspective and strength exercise from a 1-year healthcare perspective. There were no significant differences in mean QALYs between groups. From a 1-year societal perspective, at a willingness-to-pay threshold of €27 500, the probability of strength exercise or aerobic exercise being cost-effective was ≥98%. From a 1-year healthcare perspective, the probability of strength exercise or aerobic exercise being cost-effective was ≥97% and ≥76%, respectively., Conclusion: From a 1-year societal and healthcare perspective, a 12-week strength exercise or aerobic exercise programme is cost-effective compared with usual care in patients with symptomatic knee OA., Trial Registration Number: NCT01682980., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)

Objectives: To assess the associations between the single leg hop tests at two premises; baseline and the change after 12 months, and change in patient reported outcome measures and persistent instability after 12 months in patients with recurrent lateral patellar dislocation (RLPD)., Methods: 61 RLPD patients aged 12-30 with a mean (±SD) of 19.2 (±5.3) were assessed at baseline, and at 12 months after treatment with either active rehabilitation alone, or medial patellofemoral ligament reconstruction and active rehabilitation. Single leg hop for distance, triple hop for distance, crossover hop for distance and 6-metre timed hop were performed for both legs, and the Limb Symmetry Index (LSI) was calculated. Persistent patellar instability was self-reported as 'Yes' or 'No' at 12-month follow-up. Knee function in sport and recreational activities and knee-related quality of life were assessed at baseline and 12 months follow-up using the Knee injury and Osteoarthritis Outcome Score (KOOS)., Results: LSI for the baseline single leg hop for distance and the triple hop for distance was significantly associated with persistent patellar instability at 12 months follow-up with an OR of 0.94 (95% CI 0.88 to 0.99) and OR of 0.91 (95% CI 0.84 to 0.99), respectively. No other statistically significant associations were detected., Conclusion: Individuals with higher LSI values for the single leg hop for distance and triple hop for distance conducted at baseline had lower odds for persistent patellar instability at 12 months follow-up. Clinicians can use results from these hop tests to assess the risk of future recurrent patellar instability prior to treatment., Study Design: Retrospective cohort study., Trial Registration Number: NCT02263807., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To evaluate the efficacy of strength exercise or aerobic exercise compared to usual care on knee-related quality of life (QoL) and knee function at 4 months and 1 year in individuals with knee osteoarthritis., Methods: A three-arm randomized controlled trial (RCT) compared 12 weeks of strength exercise or aerobic exercise (stationary cycling) to usual care supervised by physiotherapists in primary care. We recruited 168 participants aged 35-70 years with symptomatic knee osteoarthritis. The primary outcome was The Knee Injury and Osteoarthritis Outcome Score (KOOS) QoL at 1 year. Secondary outcomes were self-reported function, pain, and self-efficacy, muscle strength and maximal oxygen uptake (VO 2max ) at 4 months and 1 year., Results: There were no differences between strength exercise and usual care on KOOS QoL (6.5, 95% CI -0.9 to 14), or for aerobic exercise and usual care (5.0, 95% CI -2.7 to 12.8), at 1 year. The two exercise groups showed better quadriceps muscle strength, and VO 2max at 4 months, compared to usual care., Conclusion: This trial found no statistically significant effects of two exercise programs compared to usual care on KOOS QoL at 1 year in individuals with symptomatic and radiographic knee osteoarthritis, but an underpowered sample size may explain lack of efficacy between the intervention groups and the usual care group., Gov Identifier: NCT01682980., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Objectives: To investigate whether and to what extent, return to work (RTW) expectancy and workability mediate the effect of two vocational interventions on reducing sickness absence in workers on sick leave from a musculoskeletal condition., Methods: This is a preplanned mediation analysis of a three-arm parallel randomised controlled trial which included 514 employed working adults with musculoskeletal conditions on sick leave for at least 50% of their contracted work hours for ≥7 weeks. Participants were randomly allocated (1:1:1) to one of three treatment arms; usual case management (UC) (n=174), UC plus motivational interviewing (MI) (n=170) and UC plus a stratified vocational advice intervention (SVAI) (n=170). The primary outcome was the number of sickness absence days over 6 months from randomisation. Hypothesised mediators included RTW expectancy and workability assessed 12 weeks after randomisation., Results: The mediated effect of the MI arm compared with UC on sickness absence days through RTW expectancy was -4.98 days (-8.89 to -1.04), and workability was -3.17 days (-8.55 to 2.32). The mediated effect of the SVAI arm compared with UC on sickness absence days through RTW expectancy was -4.39 days (-7.60 to -1.47), and workability was -3.21 days (-7.90 to 1.50). The mediated effects for workability were not statistically significant., Conclusions: Our study provides new evidence for the mechanisms of vocational interventions to reduce sickness absence related to sick leave due to musculoskeletal conditions. Changing an individual's expectation that RTW is likely may result in meaningful reductions in sickness absence days., Trial Registration Number: NCT03871712., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: To evaluate if adding motivational interviewing (MI) or a stratified vocational advice intervention (SVAI) to usual case management (UC), reduced sickness absence over 6 months for workers on sick leave due to musculoskeletal disorders., Methods: We conducted a three-arm parallel pragmatic randomised controlled trial including 514 employed workers (57% women, median age 49 (range 24-66)), on sick leave for at least 50% of their contracted work hours for ≥7 weeks. All participants received UC. In addition, those randomised to UC+MI were offered two MI sessions from social insurance caseworkers and those randomised to UC+SVAI were offered vocational advice from physiotherapists (participants with low/medium-risk for long-term sickness absence were offered one to two sessions, and those with high-risk were offered three to four sessions)., Results: Median sickness absence was 62 days, (95% CI 52 to 71) in the UC arm (n=171), 56 days (95% CI 43 to 70) in the UC+MI arm (n=169) and 49 days (95% CI 38 to 60) in the UC+SVAI arm (n=169). After adjusting for predefined potential confounding factors, the results showed seven fewer days in the UC+MI arm (95% CI -15 to 2) and the UC+SVAI arm (95% CI -16 to 1), compared with the UC arm. The adjusted differences were not statistically significant., Conclusions: The MI-NAV trial did not show effect on return to work of adding MI or SVAI to UC. The reduction in sickness absence over 6 months was smaller than anticipated, and uncertain due to wide CIs., Trial Registration Number: NCT03871712., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY. Published by BMJ.)

The goal of the OPTIKNEE consensus is to improve knee and overall health, to prevent osteoarthritis (OA) after a traumatic knee injury. The consensus followed a seven-step hybrid process. Expert groups conducted 7 systematic reviews to synthesise the current evidence and inform recommendations on the burden of knee injuries; risk factors for post-traumatic knee OA; rehabilitation to prevent post-traumatic knee OA; and patient-reported outcomes, muscle function and functional performance tests to monitor people at risk of post-traumatic knee OA. Draft consensus definitions, and clinical and research recommendations were generated, iteratively refined, and discussed at 6, tri-weekly, 2-hour videoconferencing meetings. After each meeting, items were finalised before the expert group (n=36) rated the level of appropriateness for each using a 9-point Likert scale, and recorded dissenting viewpoints through an anonymous online survey. Seven definitions, and 8 clinical recommendations (who to target, what to target and when, rehabilitation approach and interventions, what outcomes to monitor and how) and 6 research recommendations (research priorities, study design considerations, what outcomes to monitor and how) were voted on. All definitions and recommendations were rated appropriate (median appropriateness scores of 7-9) except for two subcomponents of one clinical recommendation, which were rated uncertain (median appropriateness score of 4.5-5.5). Varying levels of evidence supported each recommendation. Clinicians, patients, researchers and other stakeholders may use the definitions and recommendations to advocate for, guide, develop, test and implement person-centred evidence-based rehabilitation programmes following traumatic knee injury, and facilitate data synthesis to reduce the burden of knee post-traumatic knee OA., Competing Interests: Competing interests: JLW, AGC, BP, EM and CE are associate editors of the British Journal of Sports Medicine (BJSM). CLA is the editor in chief and JLW an editor with the Journal of Orthopaedic and Sports Physical Therapy (JOSPT). AGC is an associate editor of Osteoarthritis and Cartilage. SF is an associate editor for Journal of Science in Medicine and Sport. JBT holds a research grant from Pfizer outside the submitted work. STS is co-founders of Good Life with Osteoarthritis from Denmark (GLA:D), associate editor of the JOSPT and has received grants from the Lundbeck Foundation and personal fees from Munksgaard and TrustMe-Ed, outside the submitted work. CMT is project leader of GLA:D, Ireland. MAR is a project leader of the Active Living with Osteoarthritis in Norway (AktivA), a not-for-profit initiative to implement clinical guidelines in primary health care in Norway. ER is a deputy editor of Osteoarthritis and Cartilage, developer of Knee injury and Osteoarthritis Outcome Score and several other freely available patient-reported outcomes, and founder of GLA:D. KMC is a senior advisor of BJSM, project leader of the GLA:D, Australia, and holds a research grant from Levin Health outside the submitted work., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: Critically appraise and summarise the measurement properties of knee muscle strength tests after anterior cruciate ligament (ACL) and/or meniscus injury using the COnsensus-based Standards for the selection of health Measurement INstruments Risk of Bias checklist., Design: Systematic review with meta-analyses. The modified Grading of Recommendations Assessment, Development and Evaluation-guided assessment of evidence quality., Data Sources: Medline, Embase, CINAHL and SPORTSDiscus searched from inception to 5 May 2022., Eligibility Criteria for Selecting Studies: Studies evaluating knee extensor or flexor strength test reliability, measurement error, validity, responsiveness or interpretability in individuals with ACL and/or meniscus injuries with a mean injury age of ≤30 years., Results: Thirty-six studies were included involving 31 different muscle strength tests (mode and equipment) in individuals following an ACL injury and/or an isolated meniscus injury. Strength tests were assessed for reliability (n=8), measurement error (n=7), construct validity (n=27) and criterion validity (n=7). Isokinetic concentric extensor and flexor strength tests were the best rated with sufficient intrarater reliability (very low evidence quality) and construct validity (moderate evidence quality). Isotonic extensor and flexor strength tests showed sufficient criterion validity, while isometric extensor strength tests had insufficient construct and criterion validity (high evidence quality)., Conclusion: Knee extensor and flexor strength tests of individuals with ACL and/or meniscus injury lack evidence supporting their measurement properties. There is an urgent need for high-quality studies on these measurement properties. Until then, isokinetic concentric strength tests are most recommended, with isotonic strength tests a good alternative., Competing Interests: Competing interests: JLW and AGC are Associate Editors of the British Journal of Sports Medicine (BJSM). JLW is an Editor with the Journal of Orthopaedic and Sports Physical Therapy. KMC is a senior advisor of BJSM, project leader of the Good Life with Osteoarthritis from Denmark (GLA:D)—Australia a not-for profit initiative to implement clinical guidelines in primary care, and holds a research grant from Levin Health outside the submitted work. All other authors declare no competing interests., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: To critically appraise and summarise measurement properties of functional performance tests in individuals following anterior cruciate ligament (ACL) or meniscal injury., Design: Systematic review., Data Sources: Systematic searches were performed in Medline (Ovid), Embase (Ovid), CINAHL (EBSCO) and SPORTSDiscus (EBSCO) on 7 July 2021., Eligibility Criteria for Selecting Studies: Studies evaluating at least one measurement property of a functional performance test including individuals following an ACL tear or meniscal injury with a mean injury age of ≤30 years. The COnsensus-based Standards for the selection of health Measurement INstruments Risk of Bias checklist was used to assess methodological quality. A modified Grading of Recommendations Assessment, Development and Evaluation assessed evidence quality., Results: Thirty studies evaluating 26 functional performance tests following ACL injury were included. No studies were found in individuals with an isolated meniscal injury. Included studies evaluated reliability (n=5), measurement error (n=3), construct validity (n=26), structural validity (n=1) and responsiveness (n=1). The Single Leg Hop and Crossover Hop tests showed sufficient intrarater reliability (high and moderate quality evidence, respectively), construct validity (low-quality and moderate-quality evidence, respectively) and responsiveness (low-quality evidence)., Conclusion: Frequently used functional performance tests for individuals with ACL or meniscal injury lack evidence supporting their measurement properties. The Single Leg Hop and Crossover Hop are currently the most promising tests following ACL injury. High-quality studies are required to facilitate stronger recommendations of performance-based outcomes following ACL or meniscal injury., Competing Interests: Competing interests: JLW and AGC are Associate Editors of the British Journal of Sports Medicine (BJSM). JLW is an Editor with the Journal of Orthopaedic and Sports Physical Therapy. KMC is a senior advisor of BJSM, project leader of the Good Life with Osteoarthritis from Denmark (GLA:D)-Australia a not-for profit initiative to implement clinical guidelines in primary care, and holds a research grant from Levin Health outside the submitted work. CBJ an Associate Editor of Osteoarthritis and Cartilage. ER is Deputy Editor of Osteoarthritis and Cartilage, developer of Knee injury and Osteoarthritis Outcome Score (KOOS) and several other freely available patient-reported outcome measures, and founder of the GLA:D). All other authors declare no competing interests., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: There is limited knowledge on the association between lifestyle behaviour in adolescence and musculoskeletal pain in young adulthood. This study aimed to investigate whether an accumulation of adverse lifestyle behaviours in adolescents with and without musculoskeletal pain at baseline, was associated with persistent musculoskeletal pain (pain duration ≥3 consecutive months the last year) 11 years later., Methods: Longitudinal data from the Trøndelag Health Study in Norway including 1824 adolescents (13-19 years old) was analysed. The outcome was persistent musculoskeletal pain (≥3 months). The number of adverse lifestyle behaviours (low physical activity level, sleep problems, insufficient fruit/vegetables consumption, smoking, frequent alcohol intoxication [drunkenness] and/or illicit drug use) were summed up to comprise an ordinal variable and analysed with 0 or 1 adverse behaviours as the reference. Multiple logistic regression analyses, stratified by individuals with and without baseline musculoskeletal pain, were conducted. The results were expressed as odds ratios (ORs) with 95% confidence intervals (CIs)., Results: In adolescents with musculoskeletal pain at baseline, reporting ≥ four adverse lifestyle behaviours increased the odds of persistent musculoskeletal pain (OR 2.23, 95% CI 1.36, 3.66) 11 years later. Two and three adverse behaviours were not associated with future persistent musculoskeletal pain. In adolescents without musculoskeletal pain at baseline, an accumulation of adverse lifestyle behaviours was not associated with future persistent musculoskeletal pain., Conclusion: An accumulation of adverse lifestyle behaviours in adolescents with musculoskeletal pain at baseline was associated with persistent musculoskeletal pain 11 years later, but not in adolescents without musculoskeletal pain at baseline., Significance: An accumulation of four or more adverse lifestyle behaviours in adolescents with musculoskeletal pain was associated with persistent musculoskeletal pain in young adulthood. In future health care of adolescents with musculoskeletal pain, lifestyle behaviours should be assessed, with emphasis on accumulation of multiple adverse lifestyle behaviours. Focusing on an accumulation of multiple adverse lifestyle behaviours, rather than each individual behaviour, might provide a potential area for future research and interventions targeting musculoskeletal pain in youth., (© 2022 The Authors. European Journal of Pain published by John Wiley & Sons Ltd on behalf of European Pain Federation - EFIC ®.)

Purpose To perform a process evaluation of a stratified vocational advice intervention (SVAI), delivered by physiotherapists in primary care, for people on sick leave with musculoskeletal disorders participating in a randomised controlled trial. The research questions concerned how the SVAI was delivered, the content of the SVAI and the physiotherapists' experiences from delivering the SVAI. Methods We used qualitative and quantitative data from 148 intervention logs documenting the follow-up provided to each participant, recordings of 18 intervention sessions and minutes from 20 meetings with the physiotherapists. The log data were analysed with descriptive statistics. A qualitative content analysis was performed of the recordings, and we identified facilitators and barriers for implementation from the minutes. Results Of 170 participants randomised to the SVAI 152 (89%) received the intervention and 148 logs were completed. According to the logs, 131 participants received the correct number of sessions (all by telephone) and 146 action plans were developed. The physiotherapists did not attend any workplace meetings but contacted stakeholders in 37 cases. The main themes from the recorded sessions were: 'symptom burden', 'managing symptoms', 'relations with the workplace' and 'fear of not being able to manage work'. The physiotherapists felt they were able to build rapport with most participants. However, case management was hindered by the restricted number of sessions permitted according to the protocol. Conclusion Overall, the SVAI was delivered in accordance with the protocol and is therefore likely to be implementable in primary care if it is effective in reducing sick leave., (© 2021. The Author(s).)

Objective: To update a systematic review on the association between knee extensor muscle weakness and the risk of incident knee osteoarthritis in women and men., Design: Systematic review and meta-analysis., Data Sources: Systematic searches in PubMed, EMBASE, SPORTDiscus, CINAHL, AMED and CENTRAL in May 2021., Eligible Criteria for Selecting Studies: Longitudinal studies with at least 2 years follow-up including baseline measure of knee extensor muscle strength, and follow-up measure of symptomatic or radiographic knee osteoarthritis. Studies including participants with known knee osteoarthritis at baseline were excluded. Risk of bias assessment was conducted using six criteria for study validity and bias. Grading of Recommendations Assessments, Development and Evaluation assessed overall quality of evidence. Meta-analysis estimated the OR for the association between knee extensor muscle weakness and incident knee osteoarthritis., Results: We included 11 studies with 46 819 participants. Low quality evidence indicated that knee extensor muscle weakness increased the odds of symptomatic knee osteoarthritis in women (OR 1.85, 95% CI 1.29 to 2.64) and in adult men (OR 1.43, 95% CI 1.14 to 1.78), and for radiographic knee osteoarthritis in women: OR 1.43 (95% CI 1.19 to 1.71) and in men: OR 1.39 (95% CI 1.07 to 1.82). No associations were identified for knee injured populations except for radiographic osteoarthritis in men., Discussion: There is low quality evidence that knee extensor muscle weakness is associated with incident symptomatic and radiographic knee osteoarthritis in women and men. Optimising knee extensor muscle strength may help to prevent knee osteoarthritis., Prospero Registration Number: CRD42020214976., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: No previous studies have investigated the prevalence of co-occurring neck/shoulder pain, other musculoskeletal pain, headache and depressive symptoms in adolescents. This study aimed to describe the prevalence of isolated neck/shoulder pain and the co-occurrence of neck/shoulder pain with other musculoskeletal pain, headache and depressive symptoms in Norwegian adolescents., Methods: This is a cross-sectional study using data from the Norwegian Ungdata survey (2017-2019). Adolescents from almost all municipalities in Norway answered a comprehensive questionnaire, including physical complaints. We investigated the prevalence of self-reported neck/shoulder pain in isolation and neck/shoulder pain in combination with other musculoskeletal pain, headache and depressive symptoms. The results were presented with per cent and stratified by school level and sex., Results: In total, 253,968 adolescents (50% girls) participated in the study, of which 56.5% were from lower secondary school. The total prevalence of neck/shoulder pain was 24%, but only 5% reported isolated neck/shoulder pain. Among students reporting neck/shoulder pain, half of them also reported other musculoskeletal pain, and 50% of the boys and 70% of the girls reported co-occurring headache. Depressive symptoms were reported in 28% of the boys and 45% of the girls with neck/shoulder pain., Conclusion: Neck/shoulder pain in adolescents is seldom isolated, but seems to co-occur with headache, other musculoskeletal pain and depressive symptoms. Researchers and clinicians should keep a broader health perspective in mind when approaching adolescents with neck/shoulder pain., Significance: One in five adolescents reported neck/shoulder pain in this large population-based study of Norwegian adolescents. A majority of adolescents reported neck/shoulder pain in co-occurrence with other musculoskeletal pain, headache and depression. Researchers and clinicians should assess these comorbidities when assessing adolescents with neck/shoulder pain., (© 2021 The Authors. European Journal of Pain published by John Wiley & Sons Ltd on behalf of European Pain Federation - EFIC ®.)

Purpose There is limited knowledge about motivational interviewing (MI) for people on sick leave with musculoskeletal disorders. Hence, our objective was to investigate what research on MI as a method to facilitate return to work for individuals who are on sick leave due to musculoskeletal disorders exists, and what are the results of the research? Methods We systematically searched MEDLINE, PsycINFO, EMBASE, Cochrane Library, CINAHL, Web of Science, Sociological Abstracts, Epistemonikos, SveMed + and DARE & HTA (covering 1983 to August 2019). We also searched the MINT bulletin and relevant web pages. Eligibility criteria: empirical studies investigating MI and return to work for people with musculoskeletal disorders. Two authors independently screened the records, critically appraised the studies and charted the data using a data extraction form. Results The searches identified 1264 records of which two studies were included. One randomized controlled trial (RCT) found no effect of MI on return to work for disability pensioner with back pain (n = 89, high risk of bias), while a cluster RCT found that MI increased return to work for claimants with chronic musculoskeletal disorders (n = 728, low risk of bias). Conclusions This mapping review identified a huge gap in research on MI to increase return to work for individuals with musculoskeletal disorders. Registration Current Research Information System in Norway, project id: 635823 ( https://app.cristin.no/projects/show.jsf?id=635823 ).

Background: Little research exists on the effectiveness of motivational interviewing (MI) on return to work (RTW) in workers on long term sick leave. The objectives of this study protocol is to describe a randomized controlled trial (RCT) with the objectives to compare the effectiveness and cost-effectiveness of usual case management alone with usual case management plus MI or usual case management plus stratified vocational advice intervention (SVAI), on RTW among people on sick leave due to musculoskeletal (MSK) disorders., Methods: A multi-arm RCT with economic evaluation will be conducted in Norway with recruitment of 450 participants aged 18-67 years on 50-100% sick leave for > 7 weeks due to MSK disorders. Participants will be randomized to either usual case management by the Norwegian Labour and Welfare Administration (NAV) alone, usual case management by NAV plus MI, or usual case management by NAV plus SVAI. Trained caseworkers in NAV will give two MI sessions, and physiotherapists will give 1-4 SVAI sessions depending upon risk of long-term sick leave. The primary outcome is the number of sick leave days from randomization to 6 months follow-up. Secondary outcomes are number of sick leave days at 12 months follow-up, time until sustainable RTW (≥4 weeks of at least 50% of their usual working hours) at 12 months, proportions of participants receiving sick leave benefits during 12 months of follow-up, and MSK symptoms influencing health at 12 months. Cost-utility evaluated by the EuroQoL 5D-5L and cost-benefit analyses will be performed. Fidelity of the interventions will be assessed through audio-recordings of approximately 10% of the intervention sessions., Discussion: The results from this RCT will inform stakeholders involved in supporting RTW due to MSK disorders such as staff within NAV and primary health care., Trial Registration: ClinicalTrials.gov ID: NCT03871712 registered March 12th 2020.

Background: Musculoskeletal disorders are the leading cause of sickness absence and disability pension in Norway. There is strong evidence that long-term sickness absence due to musculoskeletal disorders are associated with a reduced probability of return to work (RTW). A way to meet the economic and resource-demanding challenges related to individual follow-up of this group is to identify and treat those individuals with a high risk of prolonged sickness. The overall purposes of this project are 1) to determine the most accurate screening tool to identify people at a high risk of prolonged sickness absence due to an musculoskeletal disorder, and 2) to investigate severity of musculoskeletal health, health-related quality-of-life, health care utilization, and costs across different risk profiles in people on sick leave due to a musculoskeletal disorder., Methods: People older than 18 years of age on sick leave for at least 4 weeks due to a musculoskeletal disorder will be invited to participate in this prospective observational cohort study conducted within the Norwegian Welfare and Labor Administration (NAV) system in collaboration with OsloMet - Oslo Metropolitan University. The main outcome is sickness absence, obtained from the NAV registry. Data on sickness absence will be retrieved prospectively in the period from study inclusion to 12 months follow-up, and retrospectively 12 months before inclusion in the study. Possible risk factors will be self-reported by the participants at inclusion while health care utilization will be retrieved from registry data. To conduct analyses including 15 to 20 predictor variables, we aim at including 500-600 people on sick leave due to musculoskeletal disorders., Discussion: This study may provide tools that can be used to identify individuals with high risk of prolonged sickness absence and may thus be important from both a socioeconomic and individual perspective. Further, the study may give valuable insight into identification of sickness absence profiles and the associations between these profiles and musculoskeletal health status, health-related quality of life and costs., Trial Registration: Retrospectively registered in ClinicalTrials.gov (NCT04196634, 27.11.2019).

Background and Objective: The transition from adolescence to adulthood is a sensitive period in life for health outcomes, including back pain. The objective was to synthesize evidence on risk factors for new episodes of back pain in emerging adults (18-29 years)., Methods: The protocol was registered in PROSPERO (CRD42016046635). We searched Medline; EMBASE; AMED and other databases up to September 2018 for prospective cohort studies that estimated the association between risk factor(s) and self-reported back pain. Risk factors could be measured before or during the age range 18-29 years, and back pain could be measured during or after this age range, with at least 12 months between assessments. Risk factors assessed in ≥3 studies were summarized. Risk of bias was assessed using a 6-item checklist., Results: Forty-nine studies were included with more than 150 different risk factors studied. Nine studies had low risk of bias, 26 had moderate and 14 had high risk of bias. Age, sex, height, body mass index (BMI), smoking, physical activity level, a history of back pain, job satisfaction and structural imaging findings were investigated in three or more studies. History of back pain was the only risk factor consistently associated with back pain after adjustment (nine studies)., Conclusion: There is moderate quality evidence that a history of back pain is a risk factor for back pain. There are inconsistent associations for age, sex, height, BMI, smoking and activity level. No associations were found between job satisfaction and structural imaging findings and back pain., Significance: Emerging adulthood is a transitional period of life with changes in life style, potentially influencing future musculoskeletal health. This systematic review included 49 articles evaluating more than 150 potential risk factors for back pain, one of the most prevalent musculoskeletal disorders. No consistent results were found for life style factors such as physical activity level or BMI, both highlighted as important risk factors in previous literature. Importantly, a previous episode of back pain was a consistent risk factor for a new episode of back pain across several studies, and further investigation of risk factors for the first back pain episode is needed., (© 2019 The Authors. European Journal of Pain published by John Wiley & Sons Ltd on behalf of European Pain Federation - EFIC®.)

Based on the strong linear relationship between heart rate (HR) and oxygen consumption, the Åstrand-Ryhming cycle ergometer test (Astrand and Ryhming in J Appl Physiol 7:218-221, 1954) is a widely used submaximal test to predict whole body maximal oxygen consumption ([Formula: see text]). However, a similar test predicting peak oxygen consumption ([Formula: see text]) in the upper extremities is not established, and may be very useful for individuals unable to use their lower extremities or/and if separation of upper extremity aerobic capacity is sought after. Thus, the aim of the current study was to develop a submaximal test predicting [Formula: see text] in arm-cycling. Forty-nine healthy volunteers (25 women: 38 ± 13 years; 24 men: 39 ± 12 years) tested arm-cycle [Formula: see text] on a protocol with 4-min, 21-W increments to exhaustion. The data were contrasted to treadmill [Formula: see text] values. Arm-cycle [Formula: see text] was 66 ± 8% of [Formula: see text] (r = 0.92, p < 0.001; women: 1.9 ± 0.4 L min -1 ; men: 3.0 ± 0.7 L min -1 ). Arm-cycle HR and [Formula: see text] exhibited correlations of r = 0.79 and r = 0.78 for women and men, respectively, while corresponding correlations between work rate and [Formula: see text] were r = 0.95 (women) and r = 0.89 (men) (all p < 0.001). Arm-cycle [Formula: see text] prediction revealed a standard error of estimate (SEE) of 11.2% (women) and 10.2% (men), and was primarily due to individual arm-cycle maximal HR (women: 173 ± 13 beats min -1 ; men: 174 ± 10 beats min -1 ; correction factor: 5-7%). In conclusion, from a single 4-min stage of submaximal arm cycling, [Formula: see text] can be predicted with a SEE of 10-11%. The arm-cycle test may have important value for individuals who rely on arms in sports and occupations, and for patients with lower extremity disabilities.

Background: Knee MRI is increasingly used to inform clinical management. Features associated with osteoarthritis are often present in asymptomatic uninjured knees; however, the estimated prevalence varies substantially between studies. We performed a systematic review with meta-analysis to provide summary estimates of the prevalence of MRI features of osteoarthritis in asymptomatic uninjured knees., Methods: We searched six electronic databases for studies reporting MRI osteoarthritis feature prevalence (ie, cartilage defects, meniscal tears, bone marrow lesions and osteophytes) in asymptomatic uninjured knees. Summary estimates were calculated using random-effects meta-analysis (and stratified by mean age: <40 vs ≥40 years). Meta-regression explored heterogeneity., Results: We included 63 studies (5397 knees of 4751 adults). The overall pooled prevalence of cartilage defects was 24% (95% CI 15% to 34%) and meniscal tears was 10% (7% to 13%), with significantly higher prevalence with age: cartilage defect <40 years 11% (6%to 17%) and ≥40 years 43% (29% to 57%); meniscal tear <40 years 4% (2% to 7%) and ≥40 years 19% (13% to 26%). The overall pooled estimate of bone marrow lesions and osteophytes was 18% (12% to 24%) and 25% (14% to 38%), respectively, with prevalence of osteophytes (but not bone marrow lesions) increasing with age. Significant associations were found between prevalence estimates and MRI sequences used, physical activity, radiographic osteoarthritis and risk of bias., Conclusions: Summary estimates of MRI osteoarthritis feature prevalence among asymptomatic uninjured knees were 4%-14% in adults aged <40 years to 19%-43% in adults ≥40 years. These imaging findings should be interpreted in the context of clinical presentations and considered in clinical decision-making., Competing Interests: Competing interests: AG is president of Boston Imaging Core Lab, LLC, and a consultant to Merck Serono, Genzyme, OrthoTrophix and TissueGene., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To investigate thresholds of strength below which individuals with knee osteoarthritis (OA) may have more difficulty carrying out physical functions of daily life. Individuals below such thresholds might benefit more from strengthening interventions than those with greater strength., Methods: We studied individuals with symptomatic OA at baseline in the Multicenter Osteoarthritis Study who had knee extensor strength measured isokinetically at 60º/second. Participants underwent a 20-meter walk test and a sit-to-stand test and answered questions from the Western Ontario and McMaster Universities Osteoarthritis Index. Physical function results were plotted against measures of quadriceps strength (Nm) (and as strength:body weight) for the worst knee. Loess technique was used to examine inflection points. Nonlinear relationships were examined in piecewise linear regression models. Differences were tested using linear and logistic regression models., Results: The study had 834 participants (65.8% women). The mean ± SD age of the participants was 62.9 ± 7.9 years. In women, there were thresholds of strength below which the slope of strength versus function was steeper: walking speed (<58 Nm), chair stand time (<32 Nm), and the McMaster Universities Osteoarthritis Index functions of rising from a chair and getting on/off the toilet (<38 Nm). We found no thresholds in men. Loess analyses using strength:weight showed similar results., Conclusion: In individuals with symptomatic knee OA, thresholds in the strength function relationship may help identify individuals, especially women, at the brink of disability insofar as strength and capacity for daily tasks. In those with low strength, small increments in strength may be associated with improvement in function and greater ease with common daily life, emphasizing the importance of preventing loss of strength., (© 2018, American College of Rheumatology.)

Background: This updated systematic review reports data from 2009 on the prevalence, and risk factors, for knee osteoarthritis (OA) more than 10 years after anterior cruciate ligament (ACL) tear., Methods: We systematically searched five databases (PubMed, EMBASE, AMED, Cinahl and SPORTDiscus) for prospective and retrospective studies published after 1 August 2008. Studies were included if they investigated participants with ACL tear (isolated or in combination with medial collateral ligament and/or meniscal injuries) and reported symptomatic and/or radiographic OA at a minimum of 10 years postinjury. We used a modified version of the Downs and Black checklist for methodological quality assessment and narrative synthesis to report results. The study protocol was registered in PROSPERO., Results: Forty-one studies were included. Low methodological quality was revealed in over half of the studies. At inclusion, age ranged from 23 to 38 years, and at follow-up from 31 to 51 years. Sample sizes ranged from 18 to 780 participants. The reported radiographic OA prevalence varied between 0% and 100% >10 years after injury, regardless of follow-up time. The studies with low and high methodological quality reported a prevalence of radiographic OA between 0%-100% and 1%-80%, respectively. One study reported symptomatic knee OA for the tibiofemoral (TF) joint (35%), and one study reported symptomatic knee OA for the patellofemoral (PF) joint (15%). Meniscectomy was the only consistent risk factor determined from the data synthesis., Conclusion: Radiographic knee OA varied between 0% and 100% in line with our previous systematic review from 2009. Symptomatic and radiographic knee OA was differentiated in two studies only, with a reported symptomatic OA prevalence of 35% for the TF joint and 15% for PF joint. Future cohort studies need to include measurement of symptomatic knee OA in this patient group., Prospero Registration Number: CRD42016042693., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Quadriceps weakness, associated with functional limitations, is a target of treatment of knee osteoarthritis (OA). Limited data exist on the relationship between modest strength increases and improvements in function. The aim of this study was to evaluate concurrent change in strength and physical function over 5 years., Methods: Among subjects from the Multicenter Osteoarthritis (MOST) study, we excluded those with knee replacement after baseline. A 3-category variable defined whether, at 5 years, knee extensor strength increased, decreased, or remained within 15% of baseline, a clinically important cut-off. The outcomes were the 5-times sit-to-stand test, 20-meter walk test, Western Ontario and McMaster Universities Osteoarthritis (WOMAC) physical function score, and 3 individual physical functions from WOMAC: arising from a chair, going up stairs, and getting on/off toilet. Linear and logistic models, stratified by sex, evaluated associations between change in strength and change in physical function over 5 years. To compare weaker versus stronger women, we stratified analyses at 56 Nm baseline strength., Results: Among 1,534 participants (60.6% women), 22% of men and 30% of women increased strength by at least 15% at 5 years. Compared with women whose strength did not change, women whose strength increased had improved chair stand performance (odds ratio 2.27 [95% confidence interval 1.56, 3.30]) but no improvement in other functions. In men, an increase in strength was not associated with significant improvement in physical function. Similar results were observed for a 20% or 30% increase., Conclusion: Modest improvement in quadriceps strength was associated with improved chair stand performance in women but not in men. Most functions did not improve with an increase in strength, and targeted interventions may be required to improve functional status., (© 2018, American College of Rheumatology.)

Objectives: To examine the associations between return to pivoting sport following ACL reconstruction (ACLR) and knee osteoarthritis (OA), and self-reported knee symptoms, function and quality of life after 15 years., Methods: Study sample included 258 participants with ACLR 15 years previously. Return to pivoting sport (handball, soccer and basketball) data were collected by interviews, and symptomatic OA was defined as Kellgren and Lawrence grade ≥2 plus almost daily knee pain in the last month. Self-reported symptoms, function and quality of life were assessed with the Knee Injury and Osteoarthritis Outcome Score. Adjusted regression models were used to analyse the associations between return to pivoting sport and OA (present or not), and self-reported outcomes. P values ≤0.05 were considered statistically significant., Results: Two hundred and ten (81%) participants (57% men) with a mean age of 39.1 (±8.7) years completed the 15-year follow-up, and 109 (52%) had returned to pivoting sport. Returning to pivoting sport was associated with less symptomatic OA (OR 0.28, 95% CI 0.09 to 0.89) and radiographic OA (OR 0.40, 95% CI 0.17 to 0.98), adjusted for age, sex, combined injury, self-reported knee function, and time between injury and surgery. Those who returned to pivoting sport had better function in activities of daily living (ADL)., Conclusion: The participants with ACLR who returned to pivoting sport had lower odds of knee OA and better self-reported ADL function. Further investigation is required to understand the clinical significance of these findings., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Objective: To prospectively evaluate the relationship between the presence or persistence of anterior knee pain (AKP) during the first 2-years following anterior cruciate ligament reconstruction (ACLR) and patellofemoral osteoarthritis (PFOA) at 15- and 20-years., Design: This study was ancillary to a long-term prospective cohort study of 221 participants following bone-patellar-tendon-bone ACLR. AKP was assessed at 1- and 2-years post-ACLR using part of the Cincinnati knee score with an additional pain location question (persistence defined as presence at both follow-ups). Radiographic PFOA (definite patellofemoral osteophyte) and symptomatic PFOA (patellofemoral osteophyte, with knee pain during past 4 weeks) was assessed at 15- and 20-years follow-up. We used generalized linear models with Poisson regression to assess the relationship between AKP and PFOA., Results: Of the 181 participants (82%) who were assessed at 15-years post-ACLR (age 39 ± 9 years; 42% female), 36 (24%) and 33 (22%) had AKP at 1- and 2-years, respectively, while 14 (8%) reported persistent AKP. Radiographic and symptomatic PFOA was observed at 15-years in 130 (72%) and 70 (39%) participants, respectively, and at 20-years in 115 (80%) and 60 (42%) participants, respectively. Neither the presence nor persistence of AKP at 1- and/or 2-years post-ACLR was associated with significantly higher risk of radiographic or symptomatic PFOA at 15- or 20-years (risk ratios <2.1)., Conclusions: Although AKP and PFOA were prevalent, AKP does not appear to be associated with long-term PFOA following ACLR., (Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)