Shoulder disorders and occupation

Pain, function and peritendinous effusion improvement after dry needling in patients with long head of biceps brachii tendinopathy: a single-blind randomized clinical trial

INTRODUCTION

Long head of biceps brachii tendinopathy, a frequent source of anterior shoulder pain, may lead to discomfort and diminished function. The objective of this study is to assess the efficacy of dry needling and transcutaneous electrical nerve stimulation in these patients.

PATIENTS AND METHODS

Thirty patients were randomized into dry needling and transcutaneous electrical nerve stimulation groups and assessed before treatment, 8 and 15 days after treatment using a visual analogue scale, shoulder pain and disability index, pressure pain threshold, tissue hardness, and biceps peritendinous effusion.

RESULTS

Both treatments significantly reduced the visual analogue scale in immediate (p < 0.001), short-term (p < 0.01), and medium-term effects (p < 0.01). Dry needling outperformed transcutaneous electrical nerve stimulation for the pain (p < 0.01) and disability (p < 0.03) subscales of the shoulder pain and disability index in the short-term and medium-term effects, respectively. Pressure pain threshold increased after both treatments but didn't last beyond 8 days. Neither treatment showed any improvements in tissue hardness of the long head of biceps brachii muscle. Notably, only the dry needling group significantly reduced biceps peritendinous effusion in both short-term and medium-term effects (p < 0.01).

CONCLUSIONS

Dry needling showed non-inferior results to transcutaneous electrical nerve stimulation in reducing pain and disability and demonstrated even superior results in reducing biceps peritendinous effusion (see Graphical Abstract).

TRIAL REGISTRATION

The Institutional Review Board of the China Medical University Hospital (CMUH107-REC2-101) approved this study, and it was registered with Identifier NCT03639454 on ClinicalTrials.gov.

Prediction model of subacromial pain syndrome in assembly workers using shoulder range of motion and muscle strength based on support vector machine

Subacromial pain syndrome (SAPS) is the most common upper-extremity musculoskeletal problem among workers. In this study, a machine learning model was built to predict and classify the presence or absence of SAPS in assembly workers with shoulder joint range of motion (ROM) and muscle strength data using support vector machine (SVM). Permutation importance was used to determine important variables for predicting workers with or without SAPS. The accuracy of the support vector classifier (SVC) polynomial model for classifying workers with SAPS was 82.4%. The important variables in model construction were internal rotation and abduction of shoulder ROM and internal rotation of shoulder muscle strength. It is possible to accurately perform SAPS classification of workers with relatively easy-to-obtain shoulder ROM and muscle strength data using this model. In addition, preventing SAPS in workers is possible by adjusting the factors affecting model building using exercise or rehabilitation programs.Practitioner summary: This study aimed to create a machine learning model that can predict and classify SAPS using shoulder ROM and muscle strength and identify the variables that are of high importance in model construction. This model could be used to predict or classify workers' SAPS and manage or prevent SAPS.

Biomechanical risk factors and subacromial pain provocation in healthy manufacturing workers

Objectives. Work-related musculoskeletal disorders (MSDs) of the shoulder may manifest subclinically. By combining risk assessment and clinical instruments, it may be advisable to recognize workers who may develop more complex MSDs early. This study aimed to evaluate the relationship between biomechanical risk factors and subacromial pain provocation in healthy manufacturing workers. Methods. A cross-sectional descriptive observational study was carried out with workers in the furniture manufacturing industry. The occupational repetitive action (OCRA) checklist was applied to detect risk factors and three clinical tests used to detect subacromial tissue reactivity: the supraspinatus test, the painful arc test and the Hawkins-Kennedy test. Results. The positivity of the clinical tests is higher in the supraspinatus test, followed by the Hawkins-Kennedy test, and lowest in the painful arc test, for both the right and left shoulders. No significant associations were found with the overall OCRA checklist index or specific biomechanical factors. Conclusion. The biomechanical risk factors and the provocation of subacromial pain reviewed in this study were not found to be related. Other physical tests that are more sensitive and adapted to workers at risk of developing musculoskeletal shoulder disorders should be explored.

Radiofrequency of suprascapular nerve as an analgesic strategy for chronic pain management. Systematic review and meta-analysis

INTRODUCTION

Chronic shoulder pain is highly prevalent in the general population. Many different analgesic strategies have been described, including radiofrequency treatment to the suprascapular nerve (RFS); however, the effectiveness this approach remains unclear, and no strong recommendation can be made. The aim of this systematic review is to analyse the latest clinical trials evaluating the effectiveness of RFS techniques applied to the suprascapular nerve in terms of management of chronic shoulder pain, post-procedural functionality, and adverse effects.

METHODS

We performed a systematic review of clinical trials retrieved from Medline, Embase and the CENTRAL databases. We included trials comparing RFS with other strategies, including placebo, that had as their primary outcome measures pain rated on a visual analogue scale, functionality rated on a shoulder pain and disability index (SPADI), and the incidence of adverse events. Risk of bias was analysed using the Cochrane RoB2 tool. Evidence was analysed using a random effects model and heterogeneity was quantified using the I2 test.

RESULTS

We identified 3030 trials, of which 8 met the inclusion criteria (n = 408). Seven had a high risk of bias. Pain intensity at 1 and 3 months was lower in patients receiving RFS, with a standardised mean difference (SMD) of -0.9 (95% CI [-1.1, 0.33], p = 0.29; I2 88%, p < 0.001) and -1.17 (95% CI [-2.49, 0.14], p = 0.08; I2 97%, p < 0.001), respectively. Functional compromise at 1 and 3 months decreased in patients receiving RFS, with an SMD of -0.31 (95% CI [-0.91, 0.29], p = 0.31; I2 80%, p < 0.001) and -1.54 (95% CI [-3.26, 0.19], p = 0.08; I2 98%, p < 0.001), respectively. No RFS-related adverse events were described.

CONCLUSION

The evidence suggests that RFS reduces pain and improves functionality. However, the certainty of the evidence is low.

The effects of exoskeleton use on human response to simulated overhead tasks with vibration

The use of occupational exoskeletons has grown fast in manufacturing industries in recent years. One major scenario of exoskeleton use in manufacturing is to assist overhead, power hand tool operations. This preliminary work aimed to determine the effects of arm-supporting exoskeletons on shoulder muscle activity and human-hand tool coupling in simulated overhead tasks with axially applied vibration. An electromagnetic shaker capable of producing the random vibration spectrum specified in ISO 10819 was hung overhead to deliver vibrations. Two passive, arm-supporting exoskeletons, with one (ExoVest) transferring load to both the shoulder and pelvic region while the second one (ExoStrap) transferring load primarily to the pelvic region, were used in testing. Testing was also done with the shaker placed in front of the body to better understand the posture and exoskeleton engagement effects. The results collected from 6 healthy male subjects demonstrate the dominating effects of the overhead working posture on increased shoulder muscle activities. Vibration led to higher muscle activities in both agonist and antagonist shoulder muscles to a less extent. Exoskeleton use reduced the anterior deltoid and serratus anterior activities by 27% to 43%. However, wearing the ExoStrap increased the upper trapezius activities by 23% to 38% in the overhead posture. Furthermore, an increased human-shaker handle coupling was observed in the OH posture when wearing the ExoVest, indicating a more demanding neuromuscular control.

Differences in Risk Factors for Rotator Cuff Tears in Young Versus Old Individuals

Background The etiology of rotator cuff tears is thought to be multifactorial with current literature that varies with regard to identifiable risk factors. The purpose of this retrospective review was to identify risk factors for full-thickness rotator cuff tears and determine whether they differ in young versus older individuals. Methods To determine the presence or absence of a rotator cuff tear, 1,561 patients with a shoulder MRI were reviewed. If a tear was present, it was further classified into a partial or full-thickness tear. Demographic variables and clinical data were collected and analyzed with a two-sided Student's t-test or Wilcoxon rank sum test for continuous variables and a Chi-square test or Fisher's exact test for categorical variables. Age and BMI were dichotomized using receiver operator curves. Results Charlson Comorbidity Index, age, BMI, sex, race, and work status were all factors that variably affected a patient's risk of experiencing a rotator cuff tear, with different factors carrying more influence on outcomes within those who are older versus those who are younger. Gender and race were found to differ as risk factors between young and older individuals. Conclusion We were able to identify risk factors overall associated with increased odds of sustaining a full-thickness rotator cuff tear. Our analyses also showed differences in the effect of gender and race as risk factors between young and older patients with rotator cuff tears. This finding may aid clinicians in counseling patients on more specific risks for their given age.

Scapular dyskinesis and overhead athletes: A systematic review of electromyography studies

OBJECTIVE

Understanding how the main scapular muscles behave in overhead athletes with scapular dyskinesis (SD).

DESIGN

Systematic Review.

SETTING

Electronic searches were performed in Pubmed (MedLine), Embase, CINAHL, and SPORTDiscus databases.

PARTICIPANTS

Overhead athletes with SD.

MAIN OUTCOME MEASURES

Electromyographic activity of the upper (UT), middle (MT), and lower (LT) trapezius, and serratus anterior (SA).

RESULTS

Eight studies were included in this review. The UT activity showed a tended to increase its activity mainly during tasks over 90° compared to 45°. SA activity had similar behavior, mainly during isometric tasks. The MT also increased its activity mainly in tasks with overhead angulations when compared to lower angulations. The LT activation tended to decrease its EMG activity at angulations below 60° in overhead athletes with SD.

CONCLUSIONS

The EMG behaviour of UT and SA for non-athletes appears to differ from what has already been described in the literature. The MT seems to be the most neglected muscle for scapular stabilization in overhead athletes with SD. The decrease in LT activity suggests that this may have implications for the performance of these athletes.

Impact of a passive upper-body exoskeleton on muscular activity and precision in overhead single and dual tasks: an explorative randomized crossover study

Introduction

Tasks performed at or above head height in industrial workplaces pose a significant challenge due to their association with musculoskeletal disorders. Upper-body exoskeletons have been identified as a potential solution for mitigating musculoskeletal loads and fighting against excessive muscular fatigue. However, the influence of such support on fine motor control, as well as on cognitive-motor interference, has received limited attention thus far. Therefore, this crossover randomized study aimed to investigate the impact of the use of a passive upper-body exoskeleton in the presence of muscular fatigue or not. Additionally, focusing on differences between single (ST) and dual (DT) industrial tasks consisting of overhead speed and accuracy exercises.

Methods

In both scenarios, N = 10 participants (5 male/5 female) engaged in an overhead precision task using a nail gun to precisely target specific areas on three differently sized regions, based on Fitts' law paradigm (speed-accuracy trade-off task). This was done with and without the passive upper-body exoskeleton, before and immediately after a fatiguing exercise of shoulder and leg muscles. In addition, a second task (dual-task, DT) was carried out in which the occurrence of an auditory signal had to be counted. The main outcomes were muscular activation of the shoulder girdle as well as the time to perform speed-accuracy tasks of different difficulty indexes (calculated by means of Fitts' law).

Results and discussion

In the absence of fatigue, the exoskeleton did not affect the speed-accuracy trade-off management of participants in the single task, but it did in the dual-task conditions. However, after muscle fatigue, the speed-accuracy trade-off was differently affected when comparing its execution with or without the exoskeleton. In general, the dual task resulted in longer times to perform the different tasks, whether it was with or without the exoskeleton. Furthermore, the use of the exoskeleton decreased muscle activity, which is associated with less physical effort, but only significantly for the M. deltoideus and M. trapezius when compared by tasks. Overall, these study findings highlight the potential supportive effects of using an upper-body exoskeleton for industrial overhead tasks.

Peripheral Nerve Stimulation of the Shoulder: A Technical Primer

Scapulalgia or shoulder pain accounts for 16% of all musculoskeletal complaints in the healthy adult population and becomes more common as we age. When this pain exceeds 3 months in duration, it is deemed to be chronic, and typically treated in an escalating manner. Spanning a continuum of conservative and non-conservative measures, chronic shoulder pain treatments range from rest and physical therapy to surgery. Since each patient presents with a unique spectrum of symptoms a customized treatment plan is often required. Over the lifetime of many of these patients, a variety of treatment options are required. One of these treatment options, peripheral nerve stimulation (PNS), is a minimally invasive procedure in which an electrical impulse is delivered through a percutaneously implanted, small caliber electrode to a peripheral nerve proximal to the lesion which interferes with the pain signals. Over the past several years, significant growth of PNS in the treatment of chronic neuropathic pain has been observed. However, the procedural techniques have not been well described. The foundation of long-term, minimally invasive percutaneous PNS in patients with chronic shoulder pain, and procedural techniques for stimulating the suprascapular and axillary nerves using fluoroscopy or ultrasonography will be described in this report.

Therapeutic exercises in the clinical practice of Brazilian physical therapists in the management of rotator cuff tendinopathy: An online survey

The objective of this study was to investigate how Brazilian physical therapists (PTs) use therapeutic exercises in the rehabilitation of individuals with rotator cuff (RC) tendinopathy. The study used an online survey with a mix of 62 open- and closed-ended questions divided into three sections: participant demographics, professional experience, and clinical practice in the rehabilitation of patients with RC tendinopathy. One hundred and fifty-nine Brazilian physical therapists completed the survey. Most of our sample recommended isometric exercises (69.9%) in the initial phase of rehabilitation and eccentric exercises (47.4%) in the advanced phase. However, there was a wide variability in determining the volume of exercises, particularly with isometric exercises. Most of our sample considered patient comfort and pain levels when adjusting exercise intensity, regardless of exercise type. The majority (48.40%) recommended weekly reassessment and modification of exercises. Additionally, despite pain being a key factor for discharge and the primary adverse effect of exercise, most of our sample would not discontinue exercises in case of pain during the early and late phases of rehabilitation. Despite the lack of consensus on some aspects, the clinical practice of our sample is in line with the current literature and practice in other countries. However, further research and implementation are crucial to enhance future rehabilitation outcomes, including exploring the exercise training volume, the safety and effectiveness of exercising with pain and identifying the optimal pain level for best results.

Arthroscopic Surgery Combined With Platelet-Rich Plasma Does Not Significantly Improve Pain, Function, Complications, and Retear Rate Compared With Arthroscopic Surgery Alone for Full-Thickness Rotator Cuff Tears: A Systematic Review and Meta-analysis

PURPOSE

To evaluate the effectiveness and safety of arthroscopic surgery combined with platelet-rich plasma (PRP) compared with arthroscopic surgery alone in the treatment of patients with full-thickness rotator cuff tears.

METHODS

The Cochrane Library, PubMed, Embase, Scopus, EBSCO, Web of Science, China National Knowledge Infrastructure, and Wanfang Database were systematically searched from inception to November 2023. Subject words combined with free words were used to collect randomized controlled trials focusing on arthroscopic surgery combined with PRP in the treatment of full-thickness rotator cuff tears. The assessment of evidence quality employed the Cochrane Collaboration risk of bias tool, and data analysis was performed using RevMan 5.3 software.

RESULTS

A total of 9 studies with 537 patients were included. The meta-analysis revealed that compared with the arthroscopic surgery alone group, the summary result of University of California Los Angeles score scores in the arthroscopic combined with PRP group was (mean difference [MD] = 1.08, 95% confidence interval [CI] 0.19∼1.97, P = .02), subgroup analysis of surgical suture method visual analog scale (VAS) single-row (MD = -1.00, 95% CI -1.50 to -0.50, P < .0001), VAS double-row (MD = -0.10, 95% CI -0.17 to -0.02, P = .02), and Constant-Murley score single-row (MD = 3.49, 95% CI 0.32∼6.66, P = .03), the difference was statistically significant, and the differences in VAS, Constant-Murley score, and Quick Disabilities of the Arm, Shoulder and Hand, complications, and retear rate were not statistically significant.

CONCLUSIONS

Patients undergoing arthroscopic repair combined with PRP treatment showed no difference in pain, function, complications, and retear rate compared with those treated with arthroscopic surgery alone.

LEVEL OF EVIDENCE

Level II, systematic review and meta-analysis of Level I and II evidence.

Ultrasound verification of palpation-based dry needling techniques of rotator cuff muscles: a prospective feasibility trial

OBJECTIVES

The primary purpose of this study is to investigate the feasibility of using ultrasound to verify the placement of narrow-gauge dry needles within the supraspinatus and infraspinatus muscles utilizing palpation-based dry needle techniques.

METHODS

This is a prospective observational study with 10 participants recruited. Each participant had a dry needle placed within the infraspinatus and supraspinatus muscles by a trained physical therapist utilizing palpation-based methods. Following needle placement, ultrasound examination was then performed to determine the feasibility of needle tip visualization within the targeted tissues.

RESULTS

The needle tip was successfully visualized on ultrasound in 19/20 cases. The needle tip accurately resided in the targeted muscle tissue in each of the 19 cases it was successfully visualized.

CONCLUSIONS

Narrow-gauge dry needles used in physical therapy practice can be consistently visualized in the supraspinatus and infraspinatus muscles using ultrasound imaging. Also, the palpation method utilized is an accurate means of guiding dry needles into the targeted rotator cuff muscles. These are significant findings because most physical therapy clinics do not have the benefit of real-time imaging guidance and must rely solely on palpation-based needling methods.

The effect of a task-specific training on upper limb performance and kinematics while performing a reaching task in a fatigued state

BACKGROUND

Fatigue impacts motor performance and upper limb kinematics. It is of interest to study whether it is possible to minimize the potentially detrimental effects of fatigue with prevention programs.

OBJECTIVE

To determine the effect of task-specific training on upper limb kinematics and motor performance when reaching in a fatigued state.

METHODS

Thirty healthy participants were recruited (Training group n = 15; Control group n = 15). Both groups took part in two evaluation sessions (Day 1 and Day 5) during which they performed a reaching task (as quickly and accurately as possible) in two conditions (rested and fatigued). During the reaching task, joint kinematics and motor performance (accuracy and speed) were evaluated. The Training group participated in three task-specific training sessions between Day 1 and Day 5; they trained once a day, for three days. The Control group did not perform any training. A three-way non-parametric ANOVA for repeated measures (Nonparametric Analysis of Longitudinal Data; NparLD) was used to assess the impact of the training (Condition [within subject]: rested, fatigued; Day [within subject]: Day 1 vs. Day 5 and Group [between subjects]: Training vs. Control).

RESULTS

After the training period, the Training group significantly improved their reaching speed compared to the Control group (Day x Group p < .01; Time effect: Training group = p < .01, Control group p = .20). No between-group difference was observed with respect to accuracy. The Training group showed a reduction in contralateral trunk rotation and lateral trunk flexion in Day 2 under the fatigue condition (Group x Day p < .04; Time effect: Training group = p < .01, Control group = p < .59).

CONCLUSION

After the 3-day training, participants demonstrated improved speed and reduced reliance on trunk compensations to complete the task under fatigue conditions. Task-specific training could help minimizing some effects of fatigue.

Establishing Normative Values for Acromion Anatomy: A Comprehensive MRI-Based Study in a Healthy Population of 996 Participants

Shoulder pain is a common issue often linked to conditions such as subacromial impingement or rotator cuff lesions. The role of the acromion in these symptoms remains a subject of debate. This study aims to establish standardized values for commonly used acromion dimensions based on whole-body MRI scans of a large and healthy population and to investigate potential correlations between acromion shape and influencing factors such as sex, age, BMI, dominant hand, and shoulder pain. The study used whole-body MRI scans from the Study of Health in Pomerania, a German population-based study. Acromion index, acromion tilt, and acromion slope were measured. Interrater variability was tested with two independent, trained viewers on 100 MRI sequences before actual measurements started. Descriptive statistics and logistic regression were used to evaluate the results. We could define reference values based on a shoulder-healthy population for each acromion parameter within the 2.5 to 97.5 percentile. No significant differences were found in acromion slope, tilt, and index between male and female participants. No significant correlations were observed between acromion morphology and anthropometric parameters such as height, weight, or BMI. No significant differences were observed in acromion parameters between dominant and non-dominant hands or stated pain intensity. This study provides valuable reference values for acromion-related parameters, offering insight into the anatomy of a healthy shoulder. The findings indicate no significant differences in acromion morphology based on sex, weight, BMI, or dominant hand. Further research is necessary to ascertain the clinical implications of these reference values. The establishment of standardized reference values opens new possibilities for enhancing clinical decision making regarding surgical interventions, such as acromioplasty.

Effects of an exoskeleton on muscle activity in tasks requiring arm elevation: Part I - Experiments in a controlled laboratory setting

BACKGROUND

Long-term work with elevated arms, or overhead work, is a risk factor for musculoskeletal complaints and disorders. Upper-limb exoskeletons are a promising tool for reducing occupational workload when working with hands above shoulder level.

OBJECTIVE

The purpose of this study was to assess the effects of upper-limb exoskeleton on muscular and physical strain and perceived exertion during dynamic work at four different shoulder joint angles. Further, we evaluated if there are any negative effects associated with the use of exoskeleton.

METHODS

A total of 15 student participants performed dynamic work in laboratory setting with and without an exoskeleton at four different shoulder angles: 60, 90, 120 and 150 degrees. Muscle electrical activity from 8 muscles of the upper body, perceived exertion, and heart rate were measured during the work task, and grip strength, muscle stiffness, tone, and elasticity from six muscles, m. deltoideus physiological cross-sectional area and muscle fiber pennation angle, and nerve conduction velocity were measured before and after the work task.

RESULTS

Based on the results, the use of exoskeleton significantly reduced the muscle activity of the upper limb, shoulder, and back muscles. The reduction was most significant when the arm elevation was 120°, and in m. deltoideus muscle activity. RPE was also positively affected indicating reduction in workload when using exoskeleton.

CONCLUSION

The results suggest that the use of upper limb exoskeleton has potential to reduce physical workload during overhead work and, consequently, reduce the risk for work-related musculoskeletal disorders.

A prospective study of 100 patients with rotator cuff tendinopathy showed no correlation between subacromial bursitis and the efficacy of ultrasound-guided corticosteroid injection

OBJECTIVES

The objective of this study was to determine whether the presence of subacromial bursitis in patients with rotator cuff tendinopathy (RCT) was associated with a better outcome after ultrasound (US)-guided subacromial corticosteroid injection.

METHODS

A single-center prospective study was performed including patients referred for subacromial injection to manage RCT. At baseline, all patients received an US-guided intra-bursal injection of betamethasone (1 ml). The primary endpoint was reduced pain 3 months (M3) after the procedure: a good responder was defined by a decrease in Visual Analogue Scale pain of more than 30%. Secondary endpoints included functional recovery assessed by the Oxford Shoulder Score (OSS) and clinical success at 6 weeks (W6). We also explored the association between good clinical response and other factors, such as US or X-ray features.

RESULTS

One hundred patients were included and 49 presented with subacromial bursitis. At M3, 60% of patients (54/100) were considered good responders. The rate of good responders did not differ between the bursitis and non-bursitis groups (p = 0.6). During follow-up, OSS improved over time whether bursitis was present or not. We did not find any US or X-ray features significantly associated with a favorable clinical outcome.

CONCLUSION

The presence of subacromial bursitis did not influence clinical outcomes at 3 months post-subacromial injection in patients suffering from RCT.

CLINICAL RELEVANCE STATEMENT

The presence of subacromial bursitis did not influence clinical outcomes at 3 months post-subacromial corticosteroid injection in patients with rotator cuff tendinopathy. For patient management, looking for ultrasonographic signs of bursitis does not appear relevant for the indication of the injection.

KEY POINTS

• Ultrasound-guided subacromial corticosteroid injections led to a significant improvement in 60% of patients suffering from rotator cuff tendinopathy. • The presence of subacromial bursitis was not associated with better improvement at 3 months post-injection. • Except for the Minnesota score referring to job satisfaction, we did not find any baseline clinical, X-ray, or ultrasound characteristics associated with a successful outcome.

Role of Magnetic Resonance Imaging (MRI) in the Diagnosis of Rotator Cuff Injuries and Correlation With Arthroscopy Findings

BACKGROUND AND AIM

The prevalent cause of shoulder pain is rotator cuff tears (RCT), which induce profound discomfort and morbidity. Hence, their detection and appropriate management become important to alleviate morbidity and enhance quality of life. Imaging has an important role in the diagnosis of such patients to guide for further management. A wide array of radiological approaches has been explored for the detection of RCT. The study aimed to assess the sensitivity (SN) and specificity (SP) of regular magnetic resonance imaging (MRI) in the diagnosis and characterization of RCT and furthermore to link the results of MRI with the arthroscopy findings. The limitations and pitfalls if any with MRI patients presenting were also addressed.

MATERIALS AND METHODS

The study was a diagnostic evaluation study conducted at the Department of Radiodiagnosis, Muslim Educational Society (MES) Medical College, Perinthalmanna, India, among individuals with RCT between December 1, 2015, and May 31, 2017. Patients who were referred for MRI and then taken up for arthroscopy were included. The findings for each tendon of rotator cuff on MRI were contrasted with that of arthroscopy, and the percentage of agreement was calculated. Additional findings relevant to the study were also noted. SN, SP, positive predictive value (PPV), and negative predictive value (NPV) of MRI were determined by taking arthroscopic findings as the gold standard.

RESULTS

The study was comprised of 36 patients assessed using MRI and arthroscopy for RCT. The study participants ranged in age from 31 to 70 years, with a mean of 52.69±8.86 years. The majority of the patients (69.4%) were between the ages of 41 and 60 years. MRI had 100% SN and SP for full-thickness supraspinatus (SS) tear, 50% SN and 100% SP for partial-thickness SS tear, 100% SN and 80% SP for full-thickness infraspinatus (IS) tear, 75% SN and 80% SP for partial-thickness IS tear, and 95% SN and 86.6% SP for subscapularis (SC) tear.

CONCLUSION

The MRI RCT investigation had a high SN, SP, and PPV compared to arthroscopy. The most frequently involved tendon reported in the present study was SS (n=35; 97.22%) followed by IS (n=32; 88.88%) and SC (n=22; 61.11%). The teres minor tendon was least commonly affected (n=0). Moreover, 61.11% (n=22) of the patients had joint effusion, 41.66% (n=15) had subacromial-subdeltoid bursal effusion, and 27.77% (n=10) had subcoracoid effusion, suggesting that RCT include joint effusion or bursal fluid. Acromioclavicular (AC) joint hypertrophy was found in 53% (n=19) of the patients, and 90% (n=17) were over 45 years old, indicating an association between age, AC joint hypertrophy, and RCT. Therefore, MRI has a good SN and SP for detecting various RCT. Therefore, it could be used to investigate a suspected RCT and should be considered a near-reference standard to arthroscopy for RCT diagnosis.

Association of Instability History and Off-Track Hill-Sachs Lesions in Anterior Shoulder Instability

Background

The glenoid track concept is now widely accepted, and its evaluation is considered essential for making decisions about surgery.

Purpose

To define preoperative descriptive data and clinical and functional features in patients with anterior glenohumeral instability according to glenoid track status and to analyze the influence of off-track Hill-Sachs (HS) lesions on preoperative shoulder function.

Study Design

Case-control study; Level of evidence, 3.

Methods

Preoperative magnetic resonance imaging or computed tomography scans were used to measure the glenoid track. Descriptive data and preoperative objective and subjective clinical and functional features were compared between patients with on-track HS lesions versus off-track HS lesions. Multivariate regression analysis was conducted to identify potential risk factors for off-track HS lesion development.

Results

A total of 235 patients (201 men, 34 women; mean age, 29.6 ± 8.6 years) were included- 134 shoulders (57%) with on-track HS lesions and 101 shoulders (43%) with off-track HS lesions. Age <20 years at first dislocation, number of dislocations, and ≥2 years between first dislocation and surgery were significantly different between the study groups (P = .005, P = .0001, and P = .01, respectively). Regarding these characteristics, the odds ratios for the risk of developing an off-track lesion were 2.67 (95% CI, 1.2-5.99)-1.2 times higher for each additional instability episode (95% CI, 1.025-1.14) and 2.42 times higher (95% CI, 1.176-4.608) for patients whose first dislocation was ≥2 years before surgery, respectively. Patients with off-track HS lesions had a significantly greater degree of instability (P = .04), worse Rowe scores (48.8 ± 15.3 vs 54.8 ± 28.3 for on-track HS lesions; P = .04), and lower Western Ontario Shoulder Instability scores (975 ± 454 vs 1179 ± 428 for on-track HS lesions; P = .01).

Conclusion

Characteristics related to a history of instability (age <20 years at first instability episode, larger number of dislocations, ≥2 years between first dislocation and surgery) were found to be risk factors for the development of an off-track HS lesion in this study. Off-track lesions led to a higher degree of instability and worse objective and subjective preoperative shoulder function versus on-track HS lesions.

High-Resolution Imaging Insights into Shoulder Joint Pain: A Comprehensive Review of Ultrasound and Magnetic Resonance Imaging (MRI)

Shoulder joint pain is a complex and prevalent clinical concern affecting individuals across various ages and lifestyles. This review delves into the pivotal role of high-resolution imaging techniques, namely ultrasound and magnetic resonance imaging (MRI), in the comprehensive assessment and management of shoulder joint pain. We explore the anatomical foundations of the shoulder, common etiologies of pain, and the significance of precise diagnosis. High-resolution imaging facilitates the identification of various shoulder pathologies and is crucial in treatment planning, surgical interventions, and long-term prognosis assessment. We examine emerging technologies, discuss challenges and limitations, and chart potential future developments, emphasizing the ongoing evolution of imaging in this critical healthcare domain. In conclusion, high-resolution imaging is an indispensable tool, continually advancing to meet the diagnostic and therapeutic needs of individuals grappling with shoulder joint pain.

Observational assessment for determining shoulder fault movements before and after corrective education in participants with chronic shoulder pain: Concurrent validity study

BACKGROUND

Movement faults (MF), described as the alteration of joint position and motion, are an important factor associated with developing shoulder pathologies. However, determining or predicting the exact MF in participants with shoulder pain is limited by the absence of clinical tools and poor validity.

PURPOSE

The aim of the study was to determine the validity of using observational assessment to MFs or controlling MFs in subjects with chronic shoulder pain during shoulder elevation and external rotation.

STUDY DESIGN

Concurrent validity study METHODS: Twenty-seven people with chronic shoulder pain were examined. The index test represented three observational assessments of MF during shoulder external rotation, elevation in the frontal plane, and elevation in the sagittal plane. Three-dimensional motion analysis represented the reference test. The movements of both shoulder joints were evaluated simultaneously, and the index and reference tests were performed concurrently.

RESULTS

The sensitivity and specificity of observational detection were good to excellent (Se: 77.5%, Sp: 81.5%) for MF and excellent (Se: 85.7%, Sp: 100%) for controlling MF. The positive and negative predictive value was (PPV: 93.9, NPV: 57.1) for MF and (PPV: 100%, NPV: 82.8%) for controlling MF. The result of the positive and negative likelihood ratio was (PLR: 5.4, NLR: 0.26) for MF and (PLR: 0, NLR: 0.18) for controlling MF.

CONCLUSIONS

The results revealed that the validity of the observational detection approach for identifying MFs was good to excellent. Moreover, the accuracy of this approach in detecting the control of MFs after patient education was excellent. There was good to excellent accuracy in most MFs once classified by their motion trajectories, except for scapula anterior tilt during glenohumeral joint external rotation or elevation.

Clinical applications of smart wearable sensors

Smart wearable sensors are electronic devices worn on the body that collect, process, and transmit various physiological data. Compared to traditional devices, their advantages in terms of portability and comfort have made them increasingly important in the medical field. This review takes a unique clinical physician's standpoint, diverging from conventional sensor-type-based classifications, and provides a comprehensive overview of the diverse clinical applications of wearable sensors in recent years. In this review, we categorize these applications according to different diseases, encompassing skin diseases and injuries, cardiovascular diseases, abnormal human motion, as well as endocrine and metabolic disorders. Additionally, we discuss the challenges and perspectives hindering the development of sensors for clinical use, emphasizing the critical need for interdisciplinary collaboration between medical and engineering professionals. Overall, this review would serve as an important reference for the future direction of sensor devices in clinical use.

Coexistence of Cervical Disc Herniation and Shoulder Soft Tissue Pathologies and the Effect of Sleeping Positions and Orthopedic Pillows

Background/aim This study investigates the degree of coexistence of cervical disc herniation and shoulder soft tissue pathology, as well as the effect of sleeping positions and orthopedic pillow use. Materials and methods This present study was conducted on 72 patients with shoulder/arm pain operated on for cervical disc herniation. Two groups were examined according to the presence of shoulder soft tissue pathology, four common sleeping positions, and the use of an orthopedic pillow. Preoperative and postoperative shoulder/arm visual analog scale (VAS) scores were compared. Results The preoperative VAS values were 7.35, while the postoperative VAS values were 3.32. Twenty-one patients (29.2%) had a disc at the C3-4 level, a rate equal to that for the C5-6 level. Twenty-four patients (33.3%) had a disc at the C4-5 level. Thirty-two cases (44.4%) slept in a side-lying position on the same side as their disc herniation. Among those with a herniated disc at the C3-4 level, 8 (53.3%) preferred sleeping side-lying on the opposite side of the disc. In contrast, those with a herniated disc at the C4-5 level more frequently (40.6%) slept side-lying on the same side as the disc. Mean VAS scores were significantly higher in cases with shoulder soft tissue pathology and were significantly lower in the group that used orthopedic pillows (p<0.001). Conclusion Shoulder soft tissue pathologies should be considered in postoperative shoulder pain. The use of orthopedic pillows is effective in preoperative and postoperative pain. Sleeping positions do not affect the shoulder/arm pain before and after the operation, but they affect the level of cervical disc herniations.

Between Two Rocks and in a Hard Place: Reflecting on the Biomechanical Basis of Shoulder Occupational Musculoskeletal Disorders

OBJECTIVE

The aim was to review the biomechanical origins of occupational shoulder damage, while considering the complexity of shoulder mechanics and musculoskeletal consequences of diverse task demands.

BACKGROUND

Accessible measures of physical exposures are the primary focus of occupational shoulder assessments and analyses. This approach has led to guidelines and intervention strategies that are often inadequate for mitigating shoulder disorders amongst the complexity of modern workplace demands. Integration of complex shoulder mechanics into occupational assessments, analyses, and interventions is critical for reducing occupational shoulder injury risk.

METHOD

This narrative review describes shoulder biomechanics in the context of common injury mechanisms and consequent injuries, with a particular focus on subacromial impingement syndrome. Several modulators of shoulder injury risk are reviewed, including fatigue, overhead work, office ergonomics considerations, and pushing and pulling task configurations.

RESULTS

Relationships between work requirements, muscular demands, fatigue, and biomechanical tissue loads exist. This review highlights that consideration of specific workplace factors should be integrated with our knowledge of the intricate arrangement and interpersonal variability of the shoulder complex to proactively evaluate occupational shoulder demands and exposures.

CONCLUSION

A standard method for evaluating shoulder muscle exposures during workplace tasks does not exist. An integrated approach is critical for improved work design and prevention of shoulder tissue damage and accompanying disability.

APPLICATION

This review is particularly relevant for researchers and practitioners, providing guidance for work design and evaluation for shoulder injury prevention by understanding the importance of the unique and complex mechanics of the shoulder.

Bari Shoulder Telemedicine Examination Protocol (B-STEP): A Standard Protocol for Personalized Remote Shoulder Examination

The COVID-19 pandemic drastically changed many aspects of the traditional functioning of health systems all around the world. In Italy, as reported by the CIO, compared to the previous year, there was a significant reduction in 2020 in overall outpatient activities by up to 75%. These data support the need for telemedicine, which represents a current challenge and can no longer be postponed in the future. This study aims to elaborate on a possible model for remote shoulder examination based on traditional tests to improve the quality of telemedicine in orthopedic and rehabilitation. Between May 2020 and November 2020, ten orthopedic surgeons individually examined six patients with a known shoulder disorder, both in hospital and via webcam according to the previously shared protocol (B-STEP). According to the 10 observers, completing 100% of the ASES score and at least 87.5% of the Constant score is possible. Shoulder ROM and many specific tests are also reproducible via webcam, but with less sensitivity, according to the subjective opinion of observers. The B-STEP is a useful protocol for the standardization of the objective examination of the shoulder via webcam. Further studies are necessary to determine if the B-STEP protocol is useful for diagnosing pathology in unknown patients and evaluating its sensitivity and specificity for each pathology.

The Effects of Body Positions and Abduction Angles on Shoulder Muscle Activity Patterns during External Rotation Exercises

BACKGROUND

Excess and repetitive glenohumeral external rotation (ER) is at a higher risk for shoulder injuries, which occurs frequently in professional sports and specific occupations. Current rehabilitation programs emphasize selective targeting of muscle activity, which can help restore dysfunctional muscle imbalances or prevent injuries. However, the impact of different body postures on GH muscle activity during ER exercises has not been fully understood. Therefore, the purpose of this study was to investigate shoulder EMG activity for different body positions and humeral abduction angles during ER exercises.

METHOD

Twenty-three healthy young men (age: 22.3 ± 2.3, height: 175.75 ± 4.02, mass: 75.37 ± 9.14) participated in this study. Surface Electromyography was recorded from seven shoulder muscles: upper trapezius, lower trapezius, serratus anterior, infraspinatus, and deltoid. Six ER exercises: three postures (sitting, supine lying, and prone lying) and two abduction angles (ABD; 45° and 90°) were tested using an isokinetic dynamometer.

RESULTS

During a sitting position, the lower trapezius/upper trapezius muscle activity ratios were significantly increased for sitting compared to supine lying and prone lying (p < 0.001, p = 0.004). Serratus anterior/upper trapezius co-contraction indices were significantly increased for 90° than 45° ABD (p < 0.001).

CONCLUSION

These findings can provide insight into new training programs aimed at restoring GH muscle imbalances.

Prevalence of Shoulder and Neck Pain Among Healthcare Workers in the Central Region of Saudi Arabia

Introduction Musculoskeletal disorders (MSDs) have a tremendous impact on working people and are becoming a serious problem in the modern society. The healthcare system is regarded as having one of the most physically demanding jobs, and the risk of musculoskeletal injuries is high. Irrespective of their age, healthcare workers (HCWs) worldwide frequently experience shoulder and neck pain. In our study, we sought to understand what initiates shoulder and neck pain, such as stress or environmental factors, and what causes shoulder and neck discomfort among Saudi Arabian healthcare professionals. Methods A descriptive, cross-sectional study was conducted from 2022 to 2023, assessing shoulder and neck pain among healthcare workers in the central region of Saudi Arabia. An online survey was used, with 409 participants aged 20 or older. The questionnaire included socio-demographic data, Shoulder Pain and Disability Index (SPADI) questionnaire to measure shoulder pain and disability, neck Bournemouth questionnaire (NBQ) to assess neck pain, and quadruple visual analogue scale (QVAS) to measure the intensity of pain. Results Of the 409 HCWs, 56% were males, and 56.5% belonged to the age group of 20-30 years. The prevalence of high-intensity pain based on QVAS criteria was 29.3%. The mean percentage of neck pain (32.3%) was slightly higher than shoulder pain (31.8%). There was a significant association between the level of pain intensity in terms of the total score of NBQ, SPADI score, and its dimensions. It is interesting to know that HCWs with associated chronic diseases had higher scores in all three questionnaires (NBQ, SPADI, and QVAS). Conclusion High-intensity musculoskeletal pain was relatively high among HCWs. It was found that neck pain affected HCWs more than shoulder pain. Furthermore, an increased pain intensity in the shoulder and neck was more frequently seen in HCWs with chronic diseases. More studies are needed to determine the causes and risk factors for neck and shoulder pain to help improve the healthcare system and patient care.

Functional ANOVA for Upper Extremity Fatigue Analysis during Dynamic Order Picking

OCCUPATIONAL APPLICATIONSMusculoskeletal disorders are prevalent among warehouse workers who engage in repetitive and dynamic tasks. To prevent such injuries, it is vital to identify the factors that influence fatigue in the upper extremities during these repetitive activities. Our study reveals that task factors, namely the bottle mass and picking rate, significantly influence upper extremity fatigue. In most cases, the fatigue indicator is a functional variable, meaning that the fatigue score or measurement is a curve captured over time, which could be modeled as a function. In this study, we demonstrate that functional data analysis tools, such as functional analysis of variance (FANOVA), prove more effective than traditional methods in specifying how task factors contribute to the development of fatigue in the upper extremities. Furthermore, since there are inherent differences among workers that could affect their fatigue development process, the data heterogeneity could be tackled by employing clustering methods.

Incidence of shoulder disorders in a cohort of healthcare workers from 2009 to 2020

PURPOSE

To estimate the incidence of shoulder disorders in a cohort of Health Care Workers (HCWs).

METHODS

4406 workers employed from 2009 to 2020, were included in the study. Occupational risk factors and jobs were assessed according to working history. Incident cases were defined in case of shoulder pain associated with functional limitations during the medical examination. The Cox regression model was used to calculate the Hazard Ratio (HR) for different work activities, adjusted for age, sex, body mass index, and previous musculoskeletal injuries, using clerks as the reference category.

RESULTS

The incidence rates of shoulder musculoskeletal disorder for men and women were 13.1 for 1000 person-years (CI 95% 10.6-16.3) and 20.1 for 1000 person-years (CI 95% 17.8-22.6) respectively. The adjusted HR was significantly increased with age (1.06, CI 95% 1.05-1.07), outpatient health activities (2.82, CI 95% 1.89-4.219), and wards health activity (2.37, CI 95% 1.68-3.33).

CONCLUSION

HCWs with high biomechanical risk such as nurses and healthcare assistants had a higher incidence of shoulder disorders. Actions are needed for better prevention in health care assistance.

Prevalence of low back pain and work-related musculoskeletal disorders in Brazilian domestics and cleaners: 2013 and 2019 National Health Survey

Introduction

Low back pain and work-related musculoskeletal disorders are two of the leading causes of absenteeism worldwide.

Objectives

To determine the prevalence and predictive factors of low back pain and work-related musculoskeletal disorders in Brazilian domestics and cleaners.

Methods

This population-based cross-sectional study used data from the 2013 and 2019 National Health Survey (Pesquisa Nacional de Saúde), involving a total of 8,160 workers. The prevalence of low back pain and work-related musculoskeletal disorders was calculated based on adjusted prevalence ratio by Poisson regression and 95%CI.

Results

The prevalence of lowback pain was 19.1% in 2013 and 20.6% in 2019, while the prevalence of musculoskeletal disorders was 2.2% in 2013 and 2.4% in 2019. Low back pain was associated with older age (prevalence ratio: 1.74; 95%CI 1.44-2.09), poor or very poor self-rated health (prevalence ratio: 2.10; 95%CI 1.76-2.50), holding a prepaid health plan (prevalence ratio: 1.27; 95%CI 1.09-1.47), and moderately severe (prevalence ratio: 2.27; 95%CI 1.84-2.80) or severe (prevalence ratio: 2.32; 95%CI 1.77-3.04) depressive symptoms. Musculoskeletal disorders affected domestics less frequently (prevalence ratio: 0.53; 95%CI 0.40-0.72) and were associated with women (prevalence ratio: 2.50; 95%CI 1.34-4.66), adults (40-59 years) (prevalence ratio: 1.79; 95%CI 1.26-2.55), holding a prepaid health plan (prevalence ratio: 2.31; 95%CI 1.63-3.26), and the presence of moderately severe (prevalence ratio: 4.00; 95%CI 2.34-6.86) or severe (prevalence ratio: 3.63; 95%CI 1.77-7.46) depressive symptoms.

Conclusions

Brazilian domestics and cleaners need interventions and improvements in health care given the prevalence of low back pain and musculoskeletal disorders as well as their association with depression.

Effectiveness of Therapeutical Interventions on the Scapulothoracic Complex in the Management of Patients with Subacromial Impingement and Frozen Shoulder: A Systematic Review

Shoulder pain is one the most common musculoskeletal complaints. The most common pathological causes of shoulder pain in the general population are subacromial impingement syndrome and adhesive capsulitis, commonly referred to as "frozen shoulder". The purpose of this study was to evaluate the role of the scapulo-thoracic complex, particularly in scapular kinematic functions, in rehabilitative interventions for shoulder pain in patients suffering from these two common conditions. This systematic review was performed using the scientific search engines PubMed, PEDro and Cochrane Library, considering only randomized controlled clinical trials. Selected articles were evaluated according to the level of evidence and methodological quality. Thirteen randomized clinical trials were selected. Interventions have been divided into three macro-categories: (1) manual therapy in patients with subacromial impingement, (2) therapeutic exercise programs including interventions on the scapulothoracic complex in patients with subacromial impingement syndrome, and (3) therapeutic exercise programs including interventions on the scapulothoracic complex in patients with frozen shoulder. Following this, a qualitative analysis was performed according to outcomes such as pain, shoulder function, and scapular kinematics. Physiotherapy exercise programs that included scapular motor control training and scapular mobilizations, in particular, those of the scapulo-thoracic complex in scapular kinematic function, represent valid alternatives in the management of patients with subacromial impingement syndrome.

Needle contact test in auricular acupuncture for shoulder pain and where effective auricular acupoints identified are positioned on the map: A controlled study

Active Points Test on auricle was renamed Needle Contact Test (or NCT), considered an extremely effective method to select most efficient auricle acupoint for Auricular Acupuncture (or AA) therapy. Our aims were to evaluate NCT efficiency as viable diagnostic option to identify the most appropriate AA acupoints to be selected for SupraSpinatus Tendinopathy (SST) associated shoulder pain treatment and to evaluate which auricle area has greater concentration of NCT positive acupoints in subjects with SST shoulder pain, comparing results with available AA ear maps. 45 subjects with SST diagnosis were enrolled. On 30 subjects in treatment group, NCT was performed on acupoints of the auricle shoulder representation areas (i.e., Scaphoid Fossa), while in 15 subjects of control group, NCT was performed on auricle areas not shoulder associated. Statistically significant lower Numeric Pain Rating Scale scores were seen for study group over time and compared to control. A small sample showed statistically significant increase of SST shoulder maximum abduction range of Movements. NCT identified best SST shoulder pain AA acupoints in Scaphoid Fossa (or SF1 and SF2). In conclusion NCT is a viable tool to efficiently identify the best AA acupoints in SST shoulder pain treatment.

Evaluation of at-home physiotherapy

An objective technological solution for tracking adherence to at-home shoulder physiotherapy is important for improving patient engagement and rehabilitation outcomes, but remains a significant challenge. The aim of this research was to evaluate performance of machine-learning (ML) methodologies for detecting and classifying inertial data collected during in-clinic and at-home shoulder physiotherapy exercise. A smartwatch was used to collect inertial data from 42 patients performing shoulder physiotherapy exercises for rotator cuff injuries in both in-clinic and at-home settings. A two-stage ML approach was used to detect out-of-distribution (OOD) data (to remove non-exercise data) and subsequently for classification of exercises. We evaluated the performance impact of grouping exercises by motion type, inclusion of non-exercise data for algorithm training, and a patient-specific approach to exercise classification. Algorithm performance was evaluated using both in-clinic and at-home data. The patient-specific approach with engineered features achieved the highest in-clinic performance for differentiating physiotherapy exercise from non-exercise activity (area under the receiver operating characteristic (AUROC) = 0.924). Including non-exercise data in algorithm training further improved classifier performance (random forest, AUROC = 0.985). The highest accuracy achieved for classifying individual in-clinic exercises was 0.903, using a patient-specific method with deep neural network model extracted features. Grouping exercises by motion type improved exercise classification. For at-home data, OOD detection yielded similar performance with the non-exercise data in the algorithm training (fully convolutional network AUROC = 0.919). Including non-exercise data in algorithm training improves detection of exercises. A patient-specific approach leveraging data from earlier patient-supervised sessions should be considered but is highly dependent on per-patient data quality.

Prognostic factors associated with improvements in patient-reported outcomes in idiopathic adhesive capsulitis

Background

The purpose of this study was to identify prognostic factors that are associated with improvements in patient-reported outcomes measures (PROMs) related to upper extremity function and pain in those suffering from idiopathic adhesive capsulitis.

Methods

All patients treated conservatively for primary idiopathic adhesive capsulitis were identified from our institutional database between 2019 and 2021. Exclusion criteria included any patients treated surgically, follow-up less than one year, or incomplete survey results. PROMs including Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity Computer Adaptive Test Version 2.0 (P-UE), Pain Interference (P-Interference), Pain Intensity (P-Intensity), and visual analog scale (VAS) pain scores. They were obtained at initial consultation and at one year to assess patient-perceived impact of their condition. Multiple linear and multivariable logistic regressions were performed to identify factors associated with improvement in patient-perceived pain and shoulder function using final PROM scores and difference in PROM scores from initial consultation. An independent t-test was used to compare baseline and one-year minimum follow-up PROMs. Odds ratios and their 95% confidence intervals were calculated for each factor; a P value of < .05 was considered statistically significant.

Results

A total of 56 patients (40 females and 16 males) were enrolled in the study with an average age of 54.7 ± 7.7 years. A significant improvement (P < .001) was demonstrated at one-year minimum outcomes for P-UE, P-Interference, P-Intensity, and VAS scores. With respect to comorbid conditions, hypothyroidism [P-UE (β: 9.57, P = .006)] was associated with greater improvements in PROMs, while hyperlipidemia [P-UE (β: -4.13, P = .01) and P-Intensity (β: 2.40, P = .02)] and anxiety [P-UE (β: -4.13, P = .03)] were associated with poorer reported changes in PROMs. Female sex [P-UE (β: 4.03, P = .007) and P-Interference (β: -2.65, P = .04)] and employment in manual labor professions [P-Interference (β: -3.07, P = .01), P-Intensity (β: -2.92, P = .006), and VAS (β: -0.66, P = .03)] were associated with significantly better patient-perceived outcomes. Hispanic heritage was associated with higher reported changes of P-Intensity (β: 8.45, P = .004) and VAS (β: 2.65, P = .002).

Conclusion

Patient-perceived improvements in PROMIS score during the natural history of adhesive capsulitis are likely multifactorial, with anxiety, hyperlipidemia, increased body mass index, and Hispanic heritage associated with reduced improvement in PROMIS scores.

Surgery for subacromial impingement syndrome and occupational biomechanical risk factors in a 16-year prospective study among male construction workers

OBJECTIVE

The aim of this study was to assess the association between occupational biomechanical exposures and the occurrence of surgical treatment for subacromial impingement syndrome (SIS).

METHODS

A cohort of 220 295 male constructions workers who participated in a national occupational health surveillance program (1971-1993) were examined prospectively over a 16-year follow-up period (2001-2016) for surgically treated SIS. Worker job title, smoking status, height, weight, and age were registered on health examination. Job titles were mapped to 21 occupational groups based on tasks and training. A job exposure matrix (JEM) was developed with exposure estimates for each occupational group. Surgical cases were determined through linkage with the Swedish national in- and outpatient registers. Poisson regression was used to assess the relative risks (RR) for each biomechanical exposure.

RESULTS

The total incidence rate of surgically treated SIS over the 16-year observation period was 201.1 cases per 100 000 person-years. Increased risk was evident for workers exposed to upper-extremity loading (push/pull/lift) (RR 1.45-2.30), high hand grip force (RR 1.47-2.23), using handheld tools (RR 1.52-2.09), frequent work with hands above shoulders (RR 1.62-2.11), static work (RR 1.77-2.26), and hand-arm vibration (RR 1.78-2.13). There was an increased risk for SIS surgery for all occupational groups (construction trades) compared with white-collar workers (RR 1.56-2.61).

CONCLUSIONS

Occupational upper-extremity load and posture exposures were associated with increased risk for surgical treatment of SIS, which underlines the need for reducing workplace exposures and early symptom detection in highly exposed occupational groups.

Effect of intraarticular pressure on glenohumeral kinematics during a simulated abduction motion: a cadaveric study

BACKGROUND

The current understanding of glenohumeral joint stability is defined by active restrictions and passive stabilizers including naturally-occurring negative intraarticular pressure. Cadaveric specimens have been used to evaluate the role of intraarticular pressure on joint stability, although, while the shoulder's negative intraarticular pressure is universally acknowledged, it has been inconsistently accounted for.

HYPOTHESIS

During continuous, passive humeral abduction, releasing the native intraarticular pressure increases joint translation, and restoring this pressure decreases joint translations.

STUDY DESIGN

Descriptive Laboratory Study.

METHODS

A validated shoulder testing system was used to passively abduct the humerus in the scapular plane and measure joint translations for seven (n = 7) cadaveric specimens. The pressure within the glenohumeral joint was measured via a 25-gauge needle during passive abduction of the arm, which was released and subsequently restored. During motion, the rotator cuff muscles were loaded using stepper motors in a force feedback loop and electromagnetic sensors were used to continuously measure the position of the humerus and scapula. Joint translation was defined according to the instant center of rotation of the glenohumeral head according to the recommendations by the International Society of Biomechanics.

RESULTS

Area under the translation versus abduction angle curve suggests that releasing the pressure within the capsule results in significantly less posterior translation of the glenohumeral head as compared to intact (85-90˚, p < 0.05). Posterior and superior translations were reduced after 70˚ of abduction when the pressure within the joint was restored.

CONCLUSION

With our testing system employing a smooth continuous passive motion, we were able to show that releasing intraarticular pressure does not have a major effect on the path of humeral head motion during glenohumeral abduction. However, both violating the capsule and restoring intraarticular pressure after releasing alter glenohumeral translations. Future studies should study the effect of simultaneous external rotation and abduction on the relationship between joint motion and IAP, especially in higher degrees of abduction.

CLINICAL RELEVANCE

Thoroughly simulating the glenohumeral joint environment in the cadaveric setting may strengthen the conclusions that can be translated from this setting to the clinic.

Minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) of upper extremity PROMIS scores in idiopathic adhesive capsulitis

INTRODUCTION

The purpose of this study is to calculate the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptom state (PASS) of Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity Computer Adaptive Testing v2.0 (UE), Pain Interference (P-Interference), and Pain Intensity (P-Intensity) in patients treated nonoperatively for idiopathic adhesive capsulitis (IAC).

METHODS

The anchor-based MCID, SCB, and PASS were calculated as the change in PROMIS scores representing the optimal cutoff for a ROC curve with an area under the curve (AUC) analysis. The distribution-based MCID was calculated as a range between the average standard error of measurement multiplied by two different constants: 1 and 2.77. Effect sizes and standardized response means (SRM) were calculated to assess the responsiveness of each PROMIS instrument while regression analyses were performed to identify factors associated with achieving these thresholds.

RESULTS

This study enrolled 115 patients. The anchor-based MCID for PROMIS UE, P-Interference, and P-Intensity was 5.11, 4.16, and 8.16, respectively. The respective SCB was 8.44, 6.65, and 10.05. The respective PASS was 8.47, 7.01, and 10.41. The odds of achieving MCID values in adhesive capsulitis were negatively affected by gender (male), higher forward elevation at the time of presentation, higher pain scores (P-Interference), need for ≥ 2 corticosteroid injections, and a concomitant diagnosis of diabetes.

CONCLUSION

The MCID, SCB, and PASS parameters for PROMIS scores can be utilized to determine the clinical meaningfulness of patient-reported improvements in these instruments during the nonoperative treatment and as a research tool to compare the efficacy of new treatments for adhesive capsulitis.

LEVEL OF EVIDENCE

Level III, basic science study, validation of outcome instruments. Key points • This is the first study to calculate the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) for the Patient-Reported Outcome Measurement Information System (PROMIS) Upper Extremity and Pain instruments in patients with idiopathic adhesive capsulitis (IAC) of the shoulder.• This study determined the impact of symptom severity, demographics, and comorbidities on achieving the MCID, SCB, and PASS for PROMIS instruments in IAC patients treated nonoperatively.

Occupational demands associated with rotator cuff disease surgery in the UK Biobank

OBJECTIVES

Physically-demanding occupations may increase rotator cuff disease (RCD) risk and need for surgery. We linked a job-exposure matrix (JEM) to the UK Biobank cohort study to measure physical occupational exposures and estimate associations with RCD surgery.

METHODS

Jobs and UK Standard Occupational Classification (SOC) codes were recorded during the UK Biobank verbal interview. Lifetime job histories were captured through a web-based survey. UK SOC codes were linked to a JEM based on the US O*NET database. O*NET-based scores [static strength, dynamic strength, general physical activities, handling/moving objects (range=1-7), time spent using hands, whole body vibration, and cramped/awkward positions (range=1-5)] were assigned to jobs. RCD surgeries were identified through linked national hospital inpatient records. Multivariable Cox regression was used to calculate hazard ratios (HR) as estimates of associations with RCD surgery. Among those with lifetime job histories, associations were estimated for duration of time with greatest exposure (top quartile of exposure).

RESULTS

Of 277 808 people reporting jobs, 1997 (0.7%) had an inpatient RCD surgery. After adjusting for age, sex, race, education, area deprivation, and body mass index, all O*NET variables considered were associated with RCD surgery (HR per point increase range=1.10-1.45, all P<0.005). A total of 100 929 people reported lifetime job histories, in which greater exposures were significantly associated with RCD surgery after >10 years of work (eg, HR for 11-20 versus 0 years with static strength score ≥4 = 2.06, 95% confidence interval 1.39-3.04).

CONCLUSIONS

Workplace physical demands are an important risk factor for RCD surgery, particularly for workers with more than a decade of exposure.

Passive shoulder exoskeleton support partially mitigates fatigue-induced effects in overhead work

BACKGROUND

Despite the potential of occupational passive shoulder exoskeletons (PSEs) to relieve overhead work, limited insights in overhead work precision performance impedes large-scale adoption in industry.

OBJECTIVE

To investigate the effect of PSE support on the reduction in task performance caused by physical fatigue.

METHODS

This experiment consisted of a randomized, counterbalanced cross-over design comparing Exo4Work PSE support and no support, in a physically fatigued state and a control condition. Precision performance was determined using execution speed and drilling errors. Muscle activity and shoulder joint kinematics were recorded.

RESULTS

Fatigue altered task performance, shoulder joint kinematics, muscle activity and subjective experience during overhead work. The PSE support mitigated the fatigue-induced changes in shoulder kinematics. Additionally, a part of the fatigue-induced co-activation of shoulder stabilizing muscles was avoided when working with the PSE. The PSE support also reduced the activity of the anterior and medial deltoid.

CONCLUSION

Physical fatigue provokes compensatory movements and increased co-contraction of muscles when executing overhead work. These fatigue-induced alterations are generally believed to increase the overall musculoskeletal load. The support provided by the PSE reduced muscle activity of muscles working to elevate the arm, but also partially mitigated those fatigue-induced effects.

SIGNIFICANCE

This study shows that the effect of PSE support on precision performance is limited, and suggested that, apart from the known effects of PSE support during overhead work, wearing the exoskeleton in a physically fatigued state may provide additional advantages.

Subacromial Content to Subacromial Space Ratio in Neutral Position of the Arm as Diagnostic Criteria of Subacromial Impingement Syndrome

Background

Shoulder impingement syndrome is one of the main causes of shoulder disability of working-class individuals. Currently, dynamic sonography of the shoulder is the modality of choice for the evaluation of shoulder impingement syndrome. The ratio of subacromial contents (SAC) and subacromial space (SAS) in neutral arm position could be used as a diagnostic parameter for the subacromial impingement syndrome (SIS), especially in patients who have difficulties in the elevation of their shoulders due to pain. To use the SAC to SAS ratio as a sonographic criterion for the diagnosis of SIS.

Methods

SAC and SAS of 772 shoulders were vertically measured in coronal view with linear transducer 7-14MHz of Toshiba Xario Prime ultrasound unit, while the patient arm was kept in the neutral position. The ratio of both the measurements was calculated, to be used as a diagnostic parameter of the SIS.

Results

The mean SAS was 10.79 ± 1.94 mm and SAC was 7.65 ± 1.43 mm. SAC-to-SAS ratio for normal shoulders was a focused value with narrow standard deviation (0.66 ± 0.03). However, shoulder impingement is confirmed by any value falls out of the range of ratio for normal shoulders. Area under the curve at 95% confidence interval was 96%, while the sensitivity at 95% confidence interval was 99.25% (97.83%-99.85%), and specificity was 80.86% (76.48%-84.74%).

Conclusion

SAC-to-SAS ratio in neutral arm position is a relatively more accurate sonographic technique for the diagnosis of SIS.

Prevalence, Patterns, and Risk Factors of Work-Related Musculoskeletal Diseases Among Teachers in the Eastern Province, Saudi Arabia: A Community-Based Retrospective Cross-Sectional Survey

Background and objective Work-related musculoskeletal diseases (WMSDs) are one of the most common occupational health concerns among teachers. They refer to a variety of degenerative and inflammatory disorders that can be triggered by the work environment of the people affected. Teachers' health is substantially significant as it impacts their productivity at work. The aim of this study was to determine the prevalence, patterns, implications, and risk factors of WMSDs among teachers in the Eastern Province of Saudi Arabia. Methods This study involved a survey based on a cross-sectional questionnaire that was distributed to 404 random school teachers located in the Eastern province of Saudi Arabia. Information such as sociodemographic characteristics, workplace characteristics, characteristics of WMSDs experienced, associated factors, and impact of the symptoms experienced was collected. Questions related to symptoms were obtained from the Nordic Musculoskeletal Questionnaire and Örebro Musculoskeletal Pain Screening Questionnaire (ÖMPSQ). The collected data were then analyzed using the SPSS Statistics version 23.0 (IBM Corp., Armonk, NY). Results Among the participants, back pain, shoulder pain, and knee pain were the most reported symptoms of WMSDs in the past 12 months, while elbow pain was the least experienced; 41.1% had pain, discomfort, or numbness that prevented them from performing regular daily activities. The regression analysis revealed a relationship between moderate to severe pain and a pain duration of more than 12 months (p=0.001). Additionally, those who were able to perform lighter work and were not having depression had a low probability of pain persistence and were able to carry out their usual work while experiencing pain (p=0.002). Conclusions In the Eastern province of Saudi Arabia, WMSDs were commonly reported by school teachers. The prevalence of WMSDs among teachers was 41.1%. The pain was described as disabling and causing a negative impact on performance. The most common locations of symptoms were the back, shoulder, and knees. Risk factors for severe pain were female gender, sleeping for six to seven hours, and pain located in the neck shoulder, elbow, hand, thigh/hips, back, knees, and ankles. Furthermore, severe pain was associated with pain duration of more than 12 months, affecting sleep, causing anxiety, and mild depression. The impact of severe pain seriously affected the daily activities of teachers.

Association between the time of physical laboral activities and leisure over shoulder pain in fruitculture workers: A cross-sectional study

BACKGROUND

Fruitculture workers are exposed to shoulder pain disorders due to long working times in overhead activities.

OBJECTIVE

This study aims to analyze the association between the time of physical work and leisure activities over the perception of shoulder pain intensity in fruit growing workers.

METHODS

This is a descriptive and correlational cross-sectional study. The sample consisted of 180 fruit-growing workers. Multivariable logistic regression was used, with an estimate of the Odds Ratio (OR) and 95% confidence intervals. The dependent variable: Numeric Pain Rating Scale (NPRS) (0-10 points), was categorized as low and high, with cutoff points of NPRS > 3 and NPRS > 4, and was associated with the independent variables (level of physical activity, personal, labour and psychosocial).

RESULTS

Workers which are insufficiently active in leisure time are more likely to report high-intensity shoulder pain, NPRS > 3 (OR: 2.39; p = 0.049) and NPRS > 4 (OR: 2.85; p = 0.036). In addition, working time in overhead activities is a risk factor for high-intensity pain for NPRS > 3 and NPRS > 4 (OR = 1.01; p < 0.001). Underweight and normal-weight workers were less likely to report shoulder pain in NPRS > 3 (OR = 0.35; p = 0.020) and in NPRS > 4 (OR = 0.20; p = 0.001).

CONCLUSION

Fruit-growing workers had a high prevalence of severe shoulder pain. In addition, workers who are insufficiently active at leisure, overweight and obese are more likely to report severe pain. It was observed that overhead tasks increase the chances of reporting high-intensity shoulder pain among workers.

Ergonomic and individual risk factors for musculoskeletal pain in the ageing workforce

Background

The present study aimed to investigate the possible association between specific ergonomic and individual risk factors and musculoskeletal pain (MSP) in the back, shoulder, hip and knee region in workers aged 50-65y.

Methods

The study was a population based cross-sectional survey. The study population comprised citizens born between 1952–1966, living in Esbjerg municipality, Denmark, ultimo 2016 (n = 23,463). A questionnaire was sent electronically or by mail. The analysis included the working population only. A multivariate logistic regression was used for each of the following dependent variables; musculoskeletal pain for the past 3 months in the back, shoulder, hip and knee, where independent variables included ergonomic exposure, age, sex, body mass index (BMI) and leisure time physical activity (LTPA).

Results

The overall response rate was 58% and the data of individuals at work (n = 9,263) demonstrated several ergonomic exposures with increased odds for pain in specific regions. Exposure to back twisted or bend, squatting or lying on knees and to carrying or lifting were associated with musculoskeletal pain in the back, whereas exposure to back twisted or bend, arms above shoulder and repeated arm movement were associated with pain in the shoulder. Exposure to back twisted or bend, repeated arm movement, squatting or lying on knees and to carrying or lifting were associated with musculoskeletal pain in the hip. Important individual risk factors were also identified. Increasing age was significantly associated with increased pain in the hip but associated with less risk for pain in the back and shoulder. Males had higher odds for pain in the back and knee compared to females but lower odds for pain in the hip. BMI was particularly important for knee pain. The level of LTPA did not have an important association with MSP in any region.

Conclusion

There is a significant positive association between ergonomic exposures and musculoskeletal pain, which were specific for the back, shoulder, hip and knee. In addition, the data demonstrated a differential association with age, sex and BMI. This needs to be considered for the treatment and classification of musculoskeletal pain and for future preventive initiatives.

EMG Signal Processing for the Study of Localized Muscle Fatigue-Pilot Study to Explore the Applicability of a Novel Method

This pilot study aimed to explore a method for characterization of the electromyogram frequency spectrum during a sustained exertion task, performed by the upper limb. Methods: Nine participants underwent an isometric localized muscle fatigue protocol on an isokinetic dynamometer until exhaustion, while monitored with surface electromyography (sEMG) of the shoulder's external rotators. Firstly, three methods of signal energy analysis based on primer frequency contributors were compared to the energy of the entire spectrum. Secondly, the chosen method of analysis was used to characterize the signal energy at beginning (T1), in the middle (T2) and at the end (T3) of the fatigue protocol and compared to the torque output and the shift in the median frequencies during the trial. Results: There were statistically significant differences between T1 and T3 for signal energy (p < 0.007) and for central frequency of the interval (p = 0.003). Moreover, the isometric peak torque was also different between T1 and T3 (p < 0.001). Overall, there were no differences between the signal energy enclosed in the 40 primer frequency contributors and the analysis of the full spectrum energy; consequently, it was the method of choice. The reported fatigue and the decrease in the produced muscle torque was consistent with fatigue-induced alterations in the electromyogram frequency spectrum. In conclusion, the developed protocol has potential to be considered as an easy-to-use method for EMG-based analysis of isometric muscle exertion until fatigue. Thus, the novelty of the proposed method is to explore, in muscle fatigue, the use of only the main contributors in the frequency domain of the EMG spectrum, avoiding surplus information, that may not represent muscle functioning. However, further studies are needed to investigate the stability of the present findings in a more comprehensive sample.

A design tool to estimate maximum acceptable manual arm forces for above-shoulder work

There is a need for design criteria for above-shoulder work to prevent shoulder fatigue and supraspinatus injuries. A tool is developed to estimate maximum acceptable manual arm forces for above-shoulder work based on 25th % female strength with adjustments for supraspinatus tendon impingement and shoulder fatigue. The tool equations are presented along with tables of maximum acceptable manual arm forces in 77 locations in the 3 D space above the shoulder that accommodates a 50th % female reach. The largest acceptable anterior force, 140.3 N, occurs at shoulder height, 0.5 m anterior to the shoulder. The largest acceptable superior force, 84.4 N, occurs at shoulder height, 0.1 m anterior and 0.2 m medial to the shoulder. The new tool provides design criteria for arm exertions at a higher level of detail than prior ergonomic tools, making it useful for engineers. Based on sensitivity analyses, the tool is robust to parameter assumptions. Practitioner summary: Above-shoulder work is associated with increased risk for shoulder fatigue and injuries. A new tool is developed that estimates maximum acceptable manual arm forces for work at or above shoulder height. The tool can be used to design acceptable above-shoulder work so that it can be accomplished by most workers. Abbreviations: AFF: arm force field; AP: anterior/posterior; DC: duty cycle; GH: glenohumeral angle; HT: humerothoracic angle; LM: lateral/medial; MAE: maximum acceptable effort; MAF: maximum acceptable force; MAS: manual arm strength; MVC: maximum voluntary contraction; N: newton; OCRA: occupational repetitive action; R: reach distance; RMS: root means square; RULA: rapid upper limb assessment; SF: scale factor; SI: superior/inferior; ST: scapulothoracic angle; T: thoracicKEY POINTSA new design tool is introduced that estimates maximum acceptable hand forces for specific locations above the shoulder.This above-shoulder tool is based on a 50th percentile female anthropometry and 25th percentile female manual arm strength.These base strengths are multiplied by scaling factors that adjust for subacromial impingement and fatigue.The tool was shown to be robust based on sensitivity analysis.

The Association Between Forceful Hand Exertions and Musculoskeletal Disorders of the Neck and Shoulder: A Prospective Cohort Study of US Manufacturing Workers

OBJECTIVE

The aim of this study was to estimate associations between biomechanical exposures and workplace neck and shoulder musculoskeletal disorders (NSMSDs) in a prospective cohort.

METHODS

Manufacturing workers (N = 349) were followed for 28 months. Biomechanical exposures were collected on each individual, and physical examinations were performed every 4 months. Prevalent cases at baseline (n = 30) were excluded from the analysis.

RESULTS

There were 18 incident cases of NSMSDs. Greater than 33% time in forceful hand exertion doubled the rate of incident NSMSDs. Greater than 18 degrees of shoulder abduction, during forceful hand exertion, increased the rate by 55%. Confidence intervals were wide.

CONCLUSIONS

Effect estimates of the relationship between forceful hand exertions and NSMSDs were consistently elevated whether measured in isolation or while in shoulder abduction. Following a larger cohort with more frequent physical examinations would improve estimates of the model.

Ergonomic Improvements to Agricultural Harvest Baskets to Reduce the Risk of Musculoskeletal Disorders among Farmers

Typical harvesting baskets (TB) are used in various agricultural workplaces; however, no study to date has reported their effect on the musculoskeletal system. Therefore, this study aimed to evaluate the effects of a novel basket with attached rotational handles (RHB) to help alleviate the work-related physical burden of farmers. We analyzed the surface electromyograms (EMGs) of seven muscles, evaluated the subjective discomfort levels and locally perceived discomfort (LPD) scores to investigate the discomfort in the whole body and seven hand muscles, respectively. The EMGs showed that muscle activity decreased in five muscles (flexor carpi ulnaris, extensor carpi radialis, lateral triceps, middle deltoid, and upper trapezius) and increased in two (biceps brachii and erector spinae) when the RHB was used (p < 0.05). The subjective discomfort score for the RHB decreased compared to that for TB (p < 0.001). The LPD scores also decreased, and the RHB and TB scores ranged from 1.25-1.40 and 3.1-3.25, respectively. The use of the RHB may prevent wrist bending, and reduce the activity of certain muscles while increasing the activity of other muscles. Therefore, it is necessary to conduct training and to evaluate the working posture while considering the affected muscles.

Sensor acquired reachable workspace in the elderly population: A cross-sectional observational study

The elderly population experiences a decline in upper extremity range of motion (ROM), impairing activities of daily living. The primary mode of quantification is by goniometer measurement. In this cross-sectional observation study, we investigate a sensor-acquired reachable workspace for assessing shoulder ROM decline in an elderly population in comparison to traditional measurements. Sixty-one healthy subjects aged ≥ 65 years were included and compared to a cohort of 39 younger subjects, aged 20 to 64. A sensor acquired reachable workspace using a Kinect motion capture camera measured the maximum reaching ability of both arms while in a seated position, measured in m2 and normalized to arm length to calculate a novel score defined as a relative surface area. This score approximates range of motion in the upper extremity. This measurement was compared to goniometer measurements, including active ROM in shoulder flexion and abduction. Total RSA shows moderate to strong correlation between goniometer in flexion and abduction in the dominant arm (R = 0.790 and R = 0.650, P < .001, respectively) and moderate correlations for the nondominant arm (R = 0.622 and R = 0.615, P < .001). Compared to the younger cohort, the elderly population demonstrated significantly reduced total RSA in the dominant arm (meanelderly = 0.774, SD = 0.09; meanyounger = 0.830, SD = 0.07, P < .001), with significant reductions in the upper lateral quadrant in both arms (dominant: meanelderly = 0.225, SD = 0.04; meanyounger = 0.241, SD = 0.01; P < .001; nondominant: meanelderly = 0.213, SD = 0.03; meanyounger = 0.228, SD = 0.01; P = .004). The test-retest reliability was strong for both dominant and nondominant total RSA (ICC > 0.762). The reachable workspace demonstrates promise as a simple and quick tool for clinicians to assess detailed and quantitative active shoulder ROM decline in the elderly population.

Increased shoulder pain across an exercise session and subsequent shoulder exercise: a prospective cohort study

Background

Shoulder complaints are common and the recommended first-line treatment is exercise therapy. However, it remains unknown if increased shoulder pain after an exercise session is a barrier for subsequent exercise dose, particularly in people with high fear-avoidance beliefs. Such knowledge could indicate ways to optimise shoulder rehabilitation. The aim was to examine whether increased shoulder pain across an exercise session was associated with a lower subsequent exercise dose, and if high fear-avoidance beliefs exaggerated this association.

Methods

We conducted a prospective cohort study using data from a randomised controlled trial in Central Denmark Region 2017–2019. Participants were employees (n = 79) with shoulder complaints and high occupational shoulder exposures. The intervention was a home-based or partly supervised exercise programme lasting 2–3 months. Linear mixed models were used to examine the associations between change in shoulder pain and exercise dose (number of repetitions, progression level (1–3), resistance level (1–3), and time until next exercise session [days]).

Results

At baseline, the participants had a median pain intensity at rest of 2 on a numerical rating scale (0–10). For a 1-cm increase in pain on a visual analogue scale (0–10 cm) during an exercise session, the subsequent number of repetitions, progression level and resistance level were − 1.3 (95% confidence interval [CI] − 3.4 to 0.9), 0.0 (95% CI − 0.1 to 0.0) and − 0.0 (95% CI − 0.1 to 0.0), respectively. Likewise, the time until next exercise session was − 0.6 (95% CI − 2.4 to 1.3) days for a 1-cm increase. There were no interactions with fear-avoidance beliefs.

Conclusion

Increased pain across an exercise session was not associated with subsequent exercise dose, regardless of fear-avoidance beliefs, among employees with shoulder complaints and high occupational shoulder exposures.

Trial registration

The trial was registered at Clinicaltrials.gov 19/05/2017 (ID: NCT03159910).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05674-2.