The role of the peripheral and central nervous systems in rotator cuff disease

Consensus on the preoperative management of patients with chronic moderate to severe shoulder pain to improve postoperative outcomes: Delphi results

BACKGROUND

Appropriate preoperative management of patients with chronic moderate to severe shoulder pain who are candidates for surgery owing to rotator cuff disease or glenohumeral osteoarthritis may improve surgery and patient outcomes, but published evidence in this regard is scarce. Therefore, the availability of recommendations on preoperative interventions based on expert consensus may serve as guidance.

METHODS

A Delphi study was conducted to develop a preoperative management algorithm based on a national expert consensus. A Delphi questionnaire was developed by a scientific committee following a systematic review of the relevant literature published during the past 10 years using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) criteria. It consisted of 48 statements divided into 5 blocks (block I, assessment and diagnosis of preoperative pain; block II, preoperative function and psychosocial aspects; block III, therapeutic objectives; block IV, treatment; and block V, follow-up and referral), and 28 experienced shoulder surgeons from across the country were invited to answer.

RESULTS

All participants responded to the Delphi questionnaire in the first round, and 25 responded in the second round (89.3% of those invited). Overall, 46 of 49 final statements reached a consensus, on the basis of which a final preoperative management algorithm was defined by the scientific committee. First, surgeons should assess shoulder pain intensity and characteristics, shoulder functionality, and psychosocial aspects using specific validated questionnaires. Preoperative therapeutic objectives should include shoulder pain control, depression and/or nocturnal sleep improvement, opioid consumption adjustment, and substance abuse cessation. Postoperative objectives regarding the degree of shoulder pain reduction or improvement in functionality and/or quality of life should be established in agreement with the patient. Treatment of preoperative chronic moderate to severe shoulder pain should comprise nonpharmacologic as well as pharmacologic interventions. Follow-up of the shoulder pain levels, treatment adherence, and mental health status of these patients may be carried out by the surgical team (surgeon and anesthesiologist) together with the primary care team. Patients with very intense shoulder pain levels may be referred to a pain unit following specific protocols.

CONCLUSION

A preoperative management algorithm for patients with chronic moderate to severe shoulder pain who are candidates for surgery owing to rotator cuff disease or glenohumeral osteoarthritis was defined based on a national expert consensus. Main points include comprehensive patient management starting with an objective assessment of shoulder pain and function, as well as quality of life; establishment of preoperative and postoperative therapeutic targets; prescription of individualized therapeutic interventions; and multidisciplinary patient follow-up. Implementation of these recommendations into clinical practice may result in better preoperative shoulder pain management and more successful surgical outcomes and patient satisfaction.

Studying intramuscular fat deposition and muscle regeneration: insights from a comparative analysis of mouse strains, injury models, and sex differences

Intramuscular fat (IMAT) infiltration, pathological adipose tissue that accumulates between muscle fibers, is a shared hallmark in a diverse set of diseases including muscular dystrophies and diabetes, spinal cord and rotator cuff injuries, as well as sarcopenia. While the mouse has been an invaluable preclinical model to study skeletal muscle diseases, they are also resistant to IMAT formation. To better understand this pathological feature, an adequate pre-clinical model that recapitulates human disease is necessary. To address this gap, we conducted a comprehensive in-depth comparison between three widely used mouse strains: C57BL/6J, 129S1/SvlmJ and CD1. We evaluated the impact of strain, sex and injury type on IMAT formation, myofiber regeneration and fibrosis. We confirm and extend previous findings that a Glycerol (GLY) injury causes significantly more IMAT and fibrosis compared to Cardiotoxin (CTX). Additionally, females form more IMAT than males after a GLY injury, independent of strain. Of all strains, C57BL/6J mice, both females and males, are the most resistant to IMAT formation. In regard to injury-induced fibrosis, we found that the 129S strain formed the least amount of scar tissue. Surprisingly, C57BL/6J of both sexes demonstrated complete myofiber regeneration, while both CD1 and 129S1/SvlmJ strains still displayed smaller myofibers 21 days post injury. In addition, our data indicate that myofiber regeneration is negatively correlated with IMAT and fibrosis. Combined, our results demonstrate that careful consideration and exploration are needed to determine which injury type, mouse model/strain and sex to utilize as preclinical model especially for modeling IMAT formation.

Effectiveness of a joint mobilizations protocol for shoulder subacromial pain syndrome: A pilot study

BACKGROUND

Subacromial pain syndrome (SPS) is the most frequent shoulder pathology. The aims of this prospective randomized study were to evaluate the effects of some specific shoulder joint mobilizations ("spin correction"), and the effectiveness of a rehabilitation program, named Shoulder Global Concept, in SPS patients.

METHODS

45 patients with SPS were randomly assigned to two groups, to benefit from a different first session of mobilizations: the experimental group received all specific mobilizations, while the control group received the same program but without the spin correction mobilizations. The second session was identical for both groups, with all specific mobilizations. Before and after the first two sessions, range of motion (ROM) in flexion, abduction, external and internal rotations, pain and functional status with Constant score and Quick Dash were evaluated. Evaluation was repeated with 24 patients after 11 rehabilitation sessions. Rehabilitation with Shoulder Global Concept included 13 mobilizations aiming at improving the ROM with passive and active-assisted mobilizations, static stretching, and muscle strengthening.

RESULTS

All ROM were improved at the end of the first session for both groups, but significantly more in the experimental group for glenohumeral (GH) abduction and external rotation (p < 0.05). Functional scores, pain and strength were significantly improved after 11 rehabilitation sessions with the Shoulder Global Concept.

CONCLUSION

This manual therapy method was able to improve shoulder mobility in one session. The additional joint mobilizations (spin correction) specifically increased GH abduction and external rotation. Rehabilitation of SPS with Shoulder Global Concept allowed to improve functional capacity and decrease pain.

Peripheral neuropathies after shoulder arthroscopy: a systematic review

Purpose

Peripheral neuropathies after shoulder arthroscopy are rare, though likely under-reported. Many resolve spontaneously, but some patients are left with permanent neurological deficits. The purpose of this study was to review the literature to better characterize this patient population, diagnostic tests performed, the timing and type of surgical intervention, and report clinical outcomes.

Methods

A systematic literature review was performed. Articles in English were identified from PubMed, EMBASE, and CINAHL in August 2021. Article titles and abstracts were screened for relevance by two authors and discordant abstracts were resolved by the senior author. Data were subsequently extracted from the included articles.

Results

Seventeen articles were identified yielding a total of 91 patients. The average age was 53 ± 12 years, and most patients were male (72%). Rotator cuff repair (62%) was the most common procedure performed. A peripheral neuropathy was identified an average of 80 ± 81 days from the index procedure (range, 0-240 days). Most commonly, peripheral nerve injury presented as a mononeuropathy, with the median nerve (39%) and ulnar nerve (17%) affected predominantly. Seventeen percent of patients underwent a secondary surgery at an average of 232 ± 157 days after the index procedure. At the final follow-up, 55% of neuropathies had resolved, 14% partially improved, and 22% showed no clinical improvement. The most proposed etiologies were postoperative immobilization (29%) and intraoperative positioning (20%), but several possible etiologies have been suggested.

Conclusions

Peripheral neuropathies after arthroscopic shoulder procedures are rare. While most spontaneously resolve, up to 1 in 5 patients may have persistent neuropathic symptoms. A high index of suspicion should be maintained throughout the postoperative period. When neurologic deficits are identified, patients should undergo a thorough diagnostic workup and be referred to a subspecialist in a timely manner.

Specific versus general exercise programme in adults with subacromial impingement syndrome: a randomised controlled trial

Objectives

Current evidence on the clinical effectiveness about the different types of exercises in the subacromial impingement syndrome (SIS) remains controversial. This study aims to compare the short-term (at 5 weeks) effects of a specific exercise programme with a general exercise programme on shoulder function in adults with SIS.

Methods

In total, 52 adults with SIS were randomly allocated to 5 weeks to perform specific exercises (experimental group, n=26) or general exercises (control group, n=26). The primary outcome was change in shoulder function, it was assessed using the Shoulder Pain and Disability Index (SPADI) from baseline to 5 weeks. Secondary end points included changes in upper limb function (Disabilities of the Arm, Shoulder, and Hand (DASH) Questionnaire), pain intensity (Visual Analog Scale (VAS)) and kinesiophobia (Tampa Scale of Kinesiophobia (TSK)).

Results

All participants completed the trial. The between-group differences at 5 weeks were: SPADI, 13.5 points (95% CI: 4.3 to 15.6; ƞ2=0.22; p=0.001); DASH, 10.1 points (95% CI: 5.6 to 15.2; ƞ2=0.27; p<0.001); VAS at rest, 0.2 cm (95% CI: 0.1 to 0.3; ƞ2=0.07; p=0.553); VAS on movement, 1.7 cm (95% CI: 0.9 to 2.2; ƞ2=0.24; p<0.001); and TSK, 16.3 points (95% CI: 13.2 to 15.3; ƞ2=0.33; p<0.001). All differences favoured the experimental group and effect sizes were medium to large for most outcomes. Mediation analyses showed that the effect of the specific exercises on shoulder function was mediated by kinesiophobia (β=2.800; 95% CI: 1.063 to 4.907) and pain on movement (β= -0.690; 95% CI: -1.176 to -0.271).

Conclusion

In adults with SIS, specific exercises may have a larger effect than general exercises. However, most differences did not reach the minimum threshold to be considered clinically important and the evidence to support exercise as standard treatment warrant further study.

Trial registration number

Brazilian Registry of Clinical Trials UTN number U111-1245-7878. Registered on 17 January 2020 (https://ensaiosclinicos.gov.br/rg/RBR-4d5zcg).

Short-term outcomes after primary reverse total shoulder arthroplasty in patients with cervical spine pathology or previous cervical spine surgery compared to those without

BACKGROUND

Cervical spine (c-spine) and shoulder pathology have been known to cause similar symptoms and often co-exist, making an accurate diagnosis difficult, especially in an elderly population. Reverse total shoulder arthroplasty (rTSA) has been shown to decrease pain and improve quality of life when shoulder pathology is the source of pain and disability. The purpose of this study was to identify the prevalence of c-spine pathology in a cohort of patients who underwent rTSA and to compare postoperative outcome scores to a cohort without c-spine pathology.

METHODS

A retrospective review was performed utilizing a single institution's operative records of primary rTSAs. Radiology reports, imaging, and operative reports were reviewed, and presence of any c-spine pathology or previous surgery were recorded. Additionally, postoperative outcome scores (American Shoulder and Elbow Surgeons [ASES], Constant Score, University of California, Los Angeles [UCLA], and Simple Shoulder Test [SST]) were evaluated at >2 years post-rTSA.

RESULTS

A total of 438 primary rTSA cases were evaluated. Of these, 143 (32.6%) had documentation of prior c-spine pathology and/or history of previous c-spine surgery. After applying further exclusion criteria, a total of 50 patients with c-spine pathology and 108 patients without c-spine pathology were found to have complete medical records and postoperative outcome scores to allow comparison between groups. Patients without c-spine pathology were found to have statistically higher postoperative UCLA, ASES, and SST scores when compared to patients with c-spine pathology. Patients without c-spine pathology also demonstrated a significant improvement in the difference between their postoperative and preoperative UCLA and ASES scores.

CONCLUSION

This study demonstrated a high prevalence of c-spine pathology (32.6%) in a cohort of patients who underwent primary rTSA. Additionally, short-term outcome scores of patients undergoing rTSA with concomitant c-spine pathology are significantly lower than those of patients without a history of c-spine pathology.

Exercise for rotator cuff tendinopathy: Proposed mechanisms of recovery

Rotator cuff (RC) tendinopathy is a common recurrent cause of shoulder pain, and resistance exercise is the first-line recommended intervention. Proposed causal mechanisms of resistance exercise for patients with RC tendinopathy consist of four domains: tendon structure, neuromuscular factors, pain and sensorimotor processing, and psychosocial factors. Tendon structure plays a role in RC tendinopathy, with decreased stiffness, increased thickness, and collagen disorganization. Neuromuscular performance deficits of altered kinematics, muscle activation, and force are present in RC tendinopathy, but advanced methods of assessing muscle performance are needed to fully assess these factors. Psychological factors of depression, anxiety, pain catastrophizing, treatment expectations, and self-efficacy are present and predict patient-reported outcomes. Central nervous system dysfunctions also exist, specifically altered pain and sensorimotor processing. Resisted exercise may normalize these factors, but limited evidence exists to explain the relationship of the four proposed domains to trajectory of recovery and defining persistent deficits limiting outcomes. Clinicians and researchers can use this model to understand how exercise mediates change in patient outcomes, develop subgroups to deliver patient-specific approach for treatment and define metrics to track recovery over time. Supporting evidence is limited, indicating the need for future studies characterizing mechanisms of recovery with exercise for RC tendinopathy.

The major pain source of rotator cuff-related shoulder pain: A narrative review on current evidence

BACKGROUND

Rotator cuff-related shoulder pain (RCRSP) was proposed to have a complex pain mechanism, but the exact aetiology is still unclear. A recent review summarised the updated research to analyse the traditional concept of shoulder impingement which may not be accurate. Current studies have demonstrated that mechanical factors including a reduction in subacromial space, scapular dyskinesia and different acromial shapes are unlikely directly contributing to RCRSP.

AIMS

Since the precise RCRSP pain mechanism remains unclear, the aim of this narrative review is to discuss possible sources of pain contributing to RCRSP according to the mechanisms-based pain classifications.

RESULTS AND DISCUSSION

Research findings on potential mechanical nociceptive factors of RCRSP are conflicting; investigations of neuropathic and central pain mechanisms of RCRSP are limited and inconclusive. Overall, available evidence has indicated moderate to strong correlations between RCRSP and chemical nociceptive sources of pain.

CONCLUSION

Results from current research may provide new directions for future studies on the aetiology of RCRSP and its clinical management towards a biochemical view instead of the traditional mechanical hypothesis.

Effectiveness of Glenohumeral Joint Mobilization on Range of Motion and Pain in Patients With Rotator Cuff Disorders: A Systematic Review and Meta-Analysis

OBJECTIVE

The purpose of this study was to determine the effectiveness of glenohumeral joint mobilization (JM) on range of motion and pain intensity in patients with rotator cuff (RC) disorders.

METHODS

An electronic search was performed in the MEDLINE, CENTRAL, Embase, PEDro, LILACS, CINAHL, SPORTDiscus, and Web of Science databases. The eligibility criteria for selecting studies included randomized clinical trials that investigated the effect of glenohumeral JM techniques with or without other therapeutic interventions on range of motion, pain intensity, and shoulder function in patients older than 18 years with RC disorders. Two authors independently performed the search, study selection, and data extraction, and assessed risk of bias. Grades of Recommendation Assessment, Development and Evaluation ratings were used to evaluate the quality of evidence in this study.

RESULTS

Twenty-four trials met the eligibility criteria, and 15 studies were included in the quantitative synthesis. At 4 to 6 weeks, for glenohumeral JM with other manual therapy techniques vs other treatments, the mean difference (MD) for shoulder flexion was -3.42° (P = .006), abduction 1.54° (P = .76), external rotation 0.65° (P = .85), and Shoulder and Pain Disability Index score 5.19 points (P = .5), and standard MD for pain intensity was 0.16 (P = .5). At 4 to 5 weeks, for the addition of glenohumeral JM to an exercise program vs exercise program alone, the MD for the visual analog scale was 0.13 cm (P = .51) and the Shoulder and Pain Disability Index score was -4.04 points (P = .01).

CONCLUSION

Compared with other treatments or an exercise program alone, the addition of glenohumeral JM with or without other manual therapy techniques does not provide significant clinical benefit with respect to shoulder function, range of motion, or pain intensity in patients with RC disorders. The quality of evidence was very low to high according to Grades of Recommendation Assessment, Development and Evaluation ratings.

RNA-Seq analysis reveals sex-dependent transcriptomic profiles of human subacromial bursa stratified by tear etiology

Rotator cuff tendinopathy, a major cause of shoulder disability, occurs due to trauma or degeneration. Our molecular understanding of traumatic and degenerative tears remains elusive. Here, we probed transcript level differences between traumatic and degenerative tears. Subacromial bursa tissues were collected from patients with traumatic or degenerative tears during arthroscopy (N = 32). Transcripts differentially expressed by tear etiology were detected by RNA-seq. RNA-seq results were validated by real-time quantitative polymerase chain reaction. We identified 334 protein-coding transcripts differentially expressed between traumatic and degenerative tears in females and 167 in males at a fold-change greater than 2. In females, XIRP2, MYL1, MYBPC1, TNNT1, and LMOD2, were highly expressed in traumatic tears whereas TPSD1, CDSN, RCVRN, LTBP4, and PTGS1 were elevated in degen tears. Transcripts elevated in traumatic tears represented muscle cell differentiation and development, and muscle contraction whereas those elevated in degenerative tears represented cell activation and immune response. In males, AZGP1, CNTFR, COL9A1, ZNF98, and EREG were highly elevated in traumatic tears whereas MYL2, HOXD11, SLC6A7, CADM1, and MMP17 were highly expressed in degenerative tears. Transcripts elevated in traumatic tears represented metabolic/catabolic processes, and transmembrane protein transport while processes related to cell cycle were mainly enriched in degenerative tears. Numerous long noncoding RNAs were differentially expressed between traumatic and degenerative tears in both sexes. In summary, this study provides insights into molecular biology of bursa in patients with rotator cuff tendon disease based on tear acuity and novel sex-based transcript differences that could inform clinical decision making in treating patients with traumatic or degenerative shoulder injuries.

Effects of percutaneous neuromodulation in neuromusculoskeletal pathologies: A systematic review

BACKGROUND

Percutaneous neuromodulation (PNM) consists in using electrical stimulation on a peripheral nerve by using a needle as an electrode in order to lessen the pain and restore both neuromuscular and nervous system functions. The aims of the present study were to evaluate the current scientific evidence of the effects of PNM on pain and physical capabilities in neuromusculoskeletal injuries.

METHODS

Data sources: There was used the PRISMA protocol. In order to do the literature research, there were used the PubMed, Cochrane, Scopus, and Web of Science databases. Study selection or eligibility criteria: There were also included experimental clinical trials published between 2010 and nowadays, tested on humans, which feature treatment based on needles with electrical stimulation in order to treat neuromusculoskeletal injuries. Study appraisal and synthesis methods: A quality assessment was performed according to the PEDro scale and reviewed the impact factor and quartile of the journal.

RESULTS

The treatment resulted in significant improvement in terms of pain intensity, pressure pain threshold, balance, muscular endurance, functionality/disability, subjective improvement, function of the descending pain modulatory system, and intake of drugs. Limitations: the lack of previous research studies on the subject and the lack of data on opioid intake in the selected studies.

CONCLUSION

Treatment based on PNM may be an alternative when treating injuries in soft tissues without significant side effects. However, there are few articles investigating the effects of PNM so more evidence is needed to draw solid conclusions.

Systematic identification of aberrant non-coding RNAs and their mediated modules in rotator cuff tears

Background: Rotator cuff tears (RCT) is the most common cause of shoulder dysfunction, however, its molecular mechanisms remain unclear. Non-coding RNAs(ncRNAs), such as long ncRNA (lncRNA), microRNA (miRNA) and circular RNA (circRNA), are involved in a variety of diseases, but little is known about their roles in RCT. Therefore, the purpose of this study is to identify dysregulated ncRNAs and understand how they influence RCT.

Methods: We performed RNA sequencing and miRNA sequencing on five pairs of torn supraspinatus muscles and matched unharmed subscapularis muscles to identify RNAs dysregulated in RCT patients. To better comprehend the fundamental biological processes, we carried out enrichment analysis of these dysregulated mRNAs or the co-expressed genes of dysregulated ncRNAs. According to the competing endogenous RNA (ceRNA) theory, we finally established ceRNA networks to explore the relationship among dysregulated RNAs in RCT.

Results: A total of 151 mRNAs, 38 miRNAs, 20 lncRNAs and 90 circRNAs were differentially expressed between torn supraspinatus muscles and matched unharmed subscapularis muscles, respectively. We found that these dysregulated mRNAs, the target mRNAs of these dysregulated miRNAs or the co-expressed mRNAs of these dysregulated ncRNAs were enriched in muscle structure development, actin-mediated cell contraction and actin binding. Then we constructed and analyzed the ceRNA network and found that the largest module in the ceRNA network was associated with vasculature development. Based on the topological properties of the largest module, we identified several important ncRNAs including hsa_circ_0000722, hsa-miR-129-5p and hsa-miR-30c-5p, whose interacting mRNAs related to muscle diseases, fat and inflammation.

Conclusion: This study presented a systematic dissection of the expression profile of mRNAs and ncRNAs in RCT patients and revealed some important ncRNAs which may contribute to the development of RCT. Such results could provide new insights for further research on RCT.

Variations in the Course and Diameter of the Suprascapular Nerve: Anatomical Study

(1) Background: Suprascapular neuropathy is an important factor contributing to shoulder pain. Given the prevalence of nerve injury and nerve block in the suprascapular notch region, as well as the frequency of arthroscopic procedures on the suprascapular notch, which are recommended in shoulder pain management, its morphology is relevant from a clinical perspective. (2) Methods: Suprascapular nerve course was studied in twelve shoulders by dissection. Its diameter was measured at omohyoid level, proximal to the suprascapular notch and distal to the spinoglenoid notch. A multi-vari chart was used in order to descriptively visualize the results. The variations found were analyzed with a mixed linear model. (3) Results: In two of the six subjects, the suprascapular nerve was divided into two motor branches proximal to the superior transverse scapular ligament. An increase in diameter around the suprascapular notch was detected, with an estimated difference between diameter means of 2.008 mm at the suprascapular notch level and 2.047 mm at the spinoglenoid notch level. (4) Conclusions: A difference in the estimated diameter detected and the fact that the motor branches, which innervate supraspinatus and infraspinatus muscle, were divided proximal to the suprascapular notch may be relevant in the diagnosis and treatment of suprascapular neuropathy and arthroscopic procedures.

Is Shoulder Pain and Disability Index a Prognostic Factor for Neuropathic Shoulder Pain?

Introduction

So far, investigations in patients with rotator cuff diseases have used pain measurement tools such as visual analog scale (VAS) for nociceptive pain as well as neuropathic pain (NeuP) specialized ones like Douleur Neuropathique 4 Question (DN4) and Pain Detect. The study’s goal was to look at the existence of NeuP in patients with chronic shoulder pain, as well as variables that may be predictive of its progression.

Methods

There were 112 outpatients in all. Current and previous pain intensity levels were documented with the numerical rating scale (NRS), the Shoulder Pain and Disability Index (SPADI) was used to assess pain and disability levels, and the S-LANSS (self-completed Leeds Assessment of Neuropathic Symptoms and Signs Pain Scale) was used to diagnose NeuP. The Pearson Chi-Square test was employed to check for any relationships between variables. The Mann-Whitney U test was also employed to check for between-group differences (with or without NeuP). To investigate factors that may be utilized as a prognostic for NeuP, logistic regression was performed, with those components (from the univariate analysis) that were statistically significant being included.

Results

According to the S-LANSS questionnaire for NeuP diagnosis, 21 patients had NeuP. According to S-LANSS, chi-square test findings revealed that NeuP is independent of sex, smoking, size, and location or rotator cuff tear. Univariate analysis with Mann-Whitney U test revealed statistically significant differences in SPADI and NRS scores between the two patient groups (p < 0.001). Α multivariate analysis using S-LANSS as the binary dependent variable and NRS currently, NRS average last month and SPADI total score as independent variables (with statistical significance) revealed that total SPADI score may be considered as an independent prognostic factor for NeuP (odds ratio = 1.189, p < 0.001).

Limitations

Due to the limited number of patients who participated in the study, the findings were deemed insufficient in terms of statistical power. In particular, the power analysis of the study (type I error probability being [a] = .05) was less than 80% (for the total SPADI score), hence relatively small. As a result, there is a limited probability of a type I error.

Conclusions

Using S-LANSS, we discovered that 18.8% of patients with rotator cuff tears had NeuP. The SPADI scores (pain and disability) in the NeuP group were substantially greater than in the nociceptive pain group. As previous studies have suggested utilizing certain levels of the VAS for pain assessment and specialized questionnaires for NeuP evaluation, we recommend that SPADI be included as a tool for emphasizing the neuropathic features of shoulder pain.

Efficacy of transdermal 4% lidocaine patches for postoperative pain management after arthroscopic rotator cuff repair: a prospective trial

Background

Postoperative pain management continues to be a challenging aspect of patient care. Lidocaine patches have shown efficacy in reducing pain in other surgical specialties and mixed results in orthopedic trials. We sought to determine the effectiveness of nonprescription lidocaine patches in reducing postoperative pain after arthroscopic rotator cuff repair

Methods

Patients undergoing primary arthroscopic rotator cuff repair were recruited from 3 surgeons at a single institution. All patients of each surgeon were randomized to a lidocaine patch or control group, with crossover occurring at the midpoint. Experimental group patients received 26 4% lidocaine gel-patches. They were provided written and visual instructions to begin wearing the lidocaine patches during daytime on postoperative day (POD) 2. They were to be switched every 8 hours and removed overnight. Control group patients received normal standard of care but did not receive a placebo control. Exclusion criteria included workmen’s compensation claims, age <18 years, history of myocardial infarction, and history of lidocaine or adhesive allergies. The American Shoulder and Elbow Surgeons shoulder survey was completed preoperatively and 2-, 6-weeks, 3-, 4.5-, and 6-months postoperatively. A 14-day visual analog scale pain and medication log was completed three times daily following repair. All patients received interscalene nerve block with bupivacaine and general anesthesia.

Results

80 (40 control, 40 lidocaine) patients were enrolled, with 53 completing follow-up. Groups were demographically similar in age (P = .22), gender (P = .20), and body mass index (P = .77). They were similar in tear pattern (P = .95), concomitant acromioplasty (P = .44), concomitant biceps tenodesis (P = .07), and number of anchors used (P = .25). There was no difference in American Shoulder and Elbow Surgeons scores at any time points (range P = .28-P = .97). Reported 14-day pain logs were not different between study groups at any time points (range P = .07-P = .99). There was no difference in opioid consumption in the first 14 days after surgery (P = .38). The lidocaine group reported less satisfaction with their pain management beginning in the evening of POD 2 (P = .05). This continued until the afternoon of POD 8 (P = .03).

Conclusion

Transdermal 4% lidocaine patches are not effective in reducing pain or opioid consumption after arthroscopic rotator cuff repair and were associated with reduced patient satisfaction.

The impact of experimental pain on shoulder movement during an arm elevated reaching task in a virtual reality environment

BACKGROUND

People with chronic shoulder pain have been shown to present with motor adaptations during arm movements. These adaptations may create abnormal physical stress on shoulder tendons and muscles. However, how and why these adaptations develop from the acute stage of pain is still not well-understood.

OBJECTIVE

To investigate motor adaptations following acute experimental shoulder pain during upper limb reaching.

METHODS

Forty participants were assigned to the Control or Pain group. They completed a task consisting of reaching targets in a virtual reality environment at three time points: (1) baseline (both groups pain-free), (2) experimental phase (Pain group experiencing acute shoulder pain induced by injecting hypertonic saline into subacromial space), and (3) Post experimental phase (both groups pain-free). Electromyographic (EMG) activity, kinematics, and performance data were collected.

RESULTS

The Pain group showed altered movement planning and execution as shown by a significant increased delay to reach muscles EMG peak and a loss of accuracy, compared to controls that have decreased their mean delay to reach muscles peak and improved their movement speed through the phases. The Pain group also showed protective kinematic adaptations using less shoulder elevation and elbow flexion, which persisted when they no longer felt the experimental pain.

CONCLUSION

Acute experimental pain altered movement planning and execution, which affected task performance. Kinematic data also suggest that such adaptations may persist over time, which could explain those observed in chronic pain populations.

High Rate of Pain Sensitization in Musculoskeletal Shoulder Diseases: A Systematic Review and Meta-analysis

BACKGROUND

Pain sensitization, defined as an increased responsiveness of nociceptive neurons to normal input, is detected in several musculoskeletal diseases, but there are no systematic reviews or meta-analyses about pain sensitization in shoulder pain.

OBJECTIVES

The aim of the study was to document pain sensitization rate and its impact in patients with shoulder pain.

MATERIALS AND METHODS

PubMed, Cochrane Library, and Web of Science were searched on January 8, 2020. Level I-IV studies, evaluating pain sensitization in musculoskeletal shoulder disorders through validated methods (questionnaires/algometry) were included. The primary outcome was pain sensitization rate. Secondary outcomes were the pain sensitivity level measured as pressure pain threshold, temporal summation, conditioned pain modulation, and suprathreshold heat pain response. Associated demographic and psychosocial factors were evaluated.

RESULTS

The rate of abnormal pressure pain threshold in patients with shoulder pain varied from 29% to 77%. Questionnaires detected pain sensitization in 11% to 24% of patients. This meta-analysis showed no difference in pressure pain threshold and central pain modulation but documented a significant difference in terms of suprathreshold heat pain response, indicating a hypersensitivity state in patients with shoulder pain versus asymptomatic controls. The only factor that was constantly found to correlate with higher sensitivity was a lower postoperative outcome.

DISCUSSION

Pain sensitization has a high rate among patients with musculoskeletal shoulder pain, regardless of the specific etiology, and this may lead to worse clinical outcome after treatment of the primary disease. The best way to assess pain sensitization still needs to be identified as the assessment methods results in used high variability in the documented pain sensitization rate.

Rehabilitation of An Analgesic Bracelet Based on Wrist-Ankle Acupuncture in Patients with Rotator Cuff Injury: A Randomized Trial

Objective

To evaluate the effect of transcutaneous electrical nerve stimulation (C-TENS) in the rehabilitation of rotator cuff injury.

Methods

A total of 60 patients diagnosed with mild to moderate rotator cuff injury were randomly divided into the control group and test group. Both groups received conventional rehabilitation treatment including physical therapy, joint mobilization, interventional therapy, and family recovery training. The test group additionally received TENS treatment on the upper area 4 or 5 of the wrist, based on the wrist-ankle acupuncture (WAA) theory. The results of the visual analogue scale (VAS), shoulder range of motion (ROM), and Constant-Murley score (CMs) were collected before and after the 1^st treatment and after the 5^th treatment. The differences of those indicators between the two groups were analyzed statistically.

Results

The VAS scores of measurement points after treatment were all improved compared with those at baseline. There was a significant difference between the two groups after the 1^st and the 5^th treatment (p < 0.05), and the improvements in the test group were better than those in the control group. The ROM of flexion, extension, abduction, adduction, internal rotation, and external rotation after the 1^st treatment and 5^th treatment in both groups were all improved compared with those at baseline. There was no significant difference between two groups. The CMs of the two groups after the 5^th treatment were all improved compared with those at baseline. There was no significant difference between two groups. No adverse events occurred during the treatment.

Conclusion

Electrical stimulation on the wrist combined with conventional rehabilitation is more effective in relieving pain than the conventional rehabilitation alone. Electrical stimulation on the wrist combined with conventional rehabilitation has no obvious effect in improving shoulder joint mobility and shoulder function.

Association between type of rotator cuff tear and functional outcomes in patients with massive and irreparable rotator cuff tear: A pre-post intervention study

BACKGROUND

The aim of this study was to analyze: (1) the differences in the pre-post change in functional outcomes after a physical therapy program by the type of massive and irreparable rotator cuff tear (MIRCT) controlling for potential confounders, and (2) the influence of lifestyle behaviors and demographic and tear tendon characteristics on function in patients over 60 years of age with conservatively treated MIRCT.

MATERIALS AND METHODS

In this pre-post intervention study, 92 patients were prospectively recruited at the Clinical Hospital San Borja Arriaran, with atraumatic MIRCT, between 60 and 75 years of age (mean: 67.9 ± 4.5 years), and the mean of length of symptoms was 16.5 months (±5.7 months). Patients received a physical therapy program consisting of manual therapy and a specific exercise program of 2 sessions per week for 12 weeks. The imaging findings were performed by 2 medical radiologists who classified the rotator cuff tear according to the criteria proposed by Collins. Shoulder function, upper limb function, and pain intensity were assessed with the Constant-Murley; Disabilities of the Arm, Shoulder, and Hand; and visual analog scale (VAS), respectively. Analysis of covariance models were estimated to assess differences in MIRCT categories between functional outcomes. Multiple regression model analysis was used for the association between the change in functional outcomes and lifestyle behaviors, and demographic and tear tendon characteristics.

RESULTS

The results showed no pre-post change in functional outcomes by type of MIRCT in all models (P > .05). There is an association between length of symptoms (P = .000), and the baseline values of the 3 functional measures (P = .000) are associated with changes in Constant-Murley; Disabilities of the Arm, Shoulder, and Hand; and VAS. In addition, changes in VAS are associated with body mass index (BMI) (P = .000), and changes in Constant-Murley are associated with gender (P = .023), BMI (P = .000), and tobacco consumption (P = .000).

CONCLUSION

There is no difference in functional outcomes by type of MIRCT after a physical therapy program controlling for potential confounders. In addition, there is an association of length of symptoms with all functional outcomes, an association of BMI with VAS and Constant-Murley questionnaire, and an association between tobacco consumption and Constant-Murley questionnaire. Our results could influence the orthopedic surgeon's decisions; thus, not predicting the functional outcome through imaging findings could lead clinicians to reconsider the need for surgery in the treatment algorithm in patients over 60 years with MIRCT. In addition, demographic characteristics and lifestyle behaviors might be considered within the patient's evaluation and follow-up to decide on surgical interventions and evaluate the clinical course of the disease. Further studies measuring additional variables and longer follow-up are needed to confirm these results.

Upper limb active joint repositioning during a multijoint task in participants with and without rotator cuff tendinopathy and effect of a rehabilitation program

STUDY DESIGN

Cross-sectional and longitudinal (exploratory) studies.

INTRODUCTION

Rotator cuff (RC) tendinopathy is the most prevalent shoulder diagnosis, and proprioception deficits are often observed in individuals with RC tendinopathy.

PURPOSE OF THE STUDY

This study aimed to evaluate upper limb proprioception during a multijoint task in participants with and without RC tendinopathy and to determine if symptoms, functional limitations, and proprioception are improved after a rehabilitation program.

METHODS

Twenty participants with and 20 without RC tendinopathy were recruited for the cross-sectional study, and 23 participants with RC tendinopathy were recruited for the longitudinal study. Proprioception was evaluated by an active joint-repositioning task: The upper limb was passively moved to a predetermined position, and the participant was asked to actively replicate the movement. The difference between the predetermined position and the replicated position was measured. The mean errors in positions of lateral, medial, and neutral rotation of the shoulder and the global mean error were reported. In addition to the active-repositioning assessment in the longitudinal study, symptoms and functional limitations were evaluated by the Disability of the Arm Shoulder and Hand questionnaire.

RESULTS

Significant deficits in active repositioning (p < .01), independent of the position, were observed in participants with RC tendinopathy compared with controls. The DASH score was improved after rehabilitation intervention (p < .001), and patients with active-repositioning deficits at baseline had reduced repositioning error (p < .05).

CONCLUSIONS

Upper limb active joint repositioning was impaired in participants with RC tendinopathy. Symptoms and functional limitations and active joint repositioning in participants with RC tendinopathy and initial deficits were improved after a 6-week global rehabilitation program.

The influence of central pain modulation on postoperative outcomes after shoulder surgery: A systematic review

OBJECTIVE

The aim of this study was to systematically review whether the altered central pain modulation has a significant influence on post-surgical outcomes in patients undergoing shoulder surgery due to musculoskeletal disorders.

METHODS

A systematic search of MEDLINE, PEDro, and EMBASE was conducted without time restriction, including observational prognostic studies. Quality in Prognostic Studies Tool was adopted for critical appraisal, and a qualitative synthesis was undertaken. Two authors independently performed study selection, data extraction, and risk of bias assessment; any disagreement was resolved by a third author. A review protocol is published in the PROSPERO registry (CRD42019122303). The data regarding the potential predictors and outcome measures were obtained from the studies.

RESULTS

11 prospective cohort studies were appraised. Overall, 952 patients were included with a sample size that ranged from 20 to 314. Studies included both arthroscopy and open surgery and presented low to moderate ROB. The prognostic factors investigated were depression, psychological distress, anxiety, catastrophizing, fear avoidance beliefs, self-efficacy and quantitative sensory testing. Only avoidance behaviors and self-efficacy were significantly related to post-surgical pain and function at 12 months after surgery.

CONCLUSION

Fear avoidance beliefs and inadequate coping strategies seem to be the most correlated factors with the worst pain and function scores. Surgeons and physical therapists should look for patients with signs of altered central pain modulation before surgery as they might be at risk of unfavorable outcome.

LEVEL OF EVIDENCE

Level II, Therapeutic Study.

Fatigue, induced via repetitive upper-limb motor tasks, influences trunk and shoulder kinematics during an upper limb reaching task in a virtual reality environment

Background

Efficient shoulder movement depends on the ability of central nervous system to integrate sensory information and to create an appropriate motor command. Various daily encountered factors can potentially compromise the execution of the command, such as fatigue. This study explored how fatigue influences shoulder movements during upper limb reaching.

Methods

Forty healthy participants were randomly assigned to one of two groups: Control or Fatigue Group. All participants completed an upper limb reaching task at baseline and post-experimental, during which they reached four targets located at 90° of shoulder abduction, 90° external rotation at 90° abduction, 120° scaption, and 120° flexion in a virtual reality environment. Following the baseline phase, the Fatigue Group completed a shoulder fatigue protocol, while Controls took a 10-minute break. Thereafter, the reaching task was repeated. Upper limb kinematic (joint angles and excursions) and spatiotemporal (speed and accuracy) data were collected during the reaching task. Electromyographic activity of the anterior and middle deltoids were also collected to characterize fatigue. Two-way repeated-measures ANOVA were performed to determine the effects of Time, Group and of the interaction between these factors.

Results

The Fatigue group showed decreased mean median power frequency and increased electromyographic amplitudes of the anterior deltoid (p < 0.05) following the fatigue protocol. Less glenohumeral elevation, increased trunk flexion and rotation and sternoclavicular elevation were also observed in the Fatigue group (Group x Time interaction, p < 0.05). The Control group improved their movement speed and accuracy in post-experimental phase, while the Fatigue group showed a decrease of movement speed and no accuracy improvement (Group x Time interaction, p < 0.05).

Conclusion

In a fatigued state, changes in movement strategy were observed during the reaching task, including increased trunk and sternoclavicular movements and less glenohumeral movement. Performance was altered as shown by the lack of accuracy improvement over time and a decrease in movement speed in the Fatigue group.

Development and validation of a shoulder-specific body-perception questionnaire in people with persistent shoulder pain

Background

There is evidence that people with persistent shoulder pain exhibit findings consistent with the presence of sensorimotor dysfunction. Sensorimotor impairments can manifest in a variety of ways, and further developing our understanding of sensorimotor dysfunction in shoulder pain may improve current models of care. The Fremantle Back Awareness Questionnaire (FreBAQ) has been developed to assess disturbed body perception specific to the back. The purpose of the present study was to develop a shoulder-specific self-perception questionnaire and evaluate the questionnaire in people with persistent shoulder pain.

Methods

The Fremantle Shoulder Awareness Questionnaire (FreSHAQ-J) was developed by modifying the FreBAQ. One hundred and twelve consecutive people with persistent shoulder pain completed the FreSHAQ-J. Thirty participants completed the FreSHAQ-J again two-weeks later to assess test-retest reliability. Rasch analysis was used to assess the psychometric properties of the FreSHAQ-J. Associations between FreSHAQ-J total score and clinical status was explored using correlational analysis.

Results

The FreSHAQ-J has acceptable category order, unidimensionality, no misfitting items, and excellent test-retest reliability. The FreSHAQ-J was moderately correlated with disability and pain catastrophization.

Conclusions

The FreSHAQ-J fits the Rasch measurement model well and is suitable for use with people with shoulder pain. Given the relationship between the FreSHAQ-J score and clinical status, change in body perception may be worth assessing when managing patients with shoulder pain.

Polymorphisms and alterations in gene expression associated with rotator cuff tear and healing following surgical repair: a systematic review

BACKGROUND

Rotator cuff tears (RCTs) are a common cause of shoulder disability, yet both conservative and surgical treatment strategies can lead to poor results in some patient populations. Enhanced understanding of the genetic processes associated with RCTs can assist in the development of more effective management options and help predict individual responses to surgical treatment. This systematic review analyzes the current literature on the genetic footprint associated with RCTs and interprets these findings to enhance the current understanding of RCT pathogenesis, potential treatment regimens, and prognostic biomarkers of outcomes after surgical repair.

METHODS

A systematic search of the Embase, PubMed, and Web of Science electronic databases was performed. Medical Subject Headings (MeSH) and Emtree index terms were formulated from the concept terms "rotator cuff tear," "genetics," and "human," and synonyms of these concepts were applied to the Web of Science search. Articles were screened against predefined inclusion and exclusion criteria. Eligible studies compared gene expression patterns and genetic polymorphisms between cases (with RCTs) and controls (without RCTs). Quality assessment was performed with studies being rated as high, moderate, or poor quality. A modified best-evidence synthesis was applied, and studies were determined to be of strong, moderate, or limited evidence.

RESULTS

The search identified 259 articles. Of these studies, 26 were eligible for review. Two studies were considered poor quality; 15 studies, moderate quality; and 9 studies, high quality. Analysis of these articles found that RCTs were associated with alterations in genes that code for the extracellular matrix, cell apoptosis, immune and inflammatory responses, and growth factor pathways. In particular, there was strong evidence of a significant association between RCTs and the genes MMP3, TNC, and ESRRB. Strong evidence of an association between BMP5 upregulation and successful healing after surgical repair was also found.

CONCLUSION

This review provides strong evidence of an genetic association with RCTs. The genotype and gene expression patterns detailed within this review can assist in deciphering the biological mechanisms resulting in RCTs, as well as predicting an individual's response to surgical repair. Future research could investigate whether manipulating these genes-or their associated signaling pathways-could assist in RCT healing and whether genetic biomarkers could be used clinically to predict patient outcomes after surgical repair of RCTs.

The Short-term Effect of Graded Motor Imagery on the Affective Components of Pain in Subjects with Chronic Shoulder Pain Syndrome: Open-Label Single-Arm Prospective Study

OBJECTIVE

To determine the short-term effect of graded motor imagery (GMI) on the affective components of pain and range of motion in subjects with chronic shoulder pain syndrome.

DESIGN

Open-label single-arm prospective study.

SETTING

The Physical Therapy Laboratory, Universidad de las Americas.

SUBJECTS

One hundred seven patients with chronic shoulder pain syndrome.

METHODS

The subjects received a six-week GMI program based on laterality training, imagined movements, and mirror therapy. We assessed pain intensity using a visual analog scale (VAS), fear of movement was assessed using the Tampa Scale of Kinesiophobia (TSK), and catastrophizing was assessed using the Pain Catastrophizing Scale (PCS). The patient's flexion active range of motion (AROM) was also recorded.

RESULTS

At the end of treatment, the VAS showed a decrease of 4.2 cm (P < 0.001, Cohen's d = 3.3), TSK showed a decrease of 17.0 points (P < 0.001, Cohen's d = 2.8), catastrophizing showed a decrease of 19.2 points (P < 0.001, Cohen's d = 3.2), and shoulder flexion AROM showed an increment of 30.3º (P < 0.000, Cohen's d = 1.6).

CONCLUSIONS

We conclude that a short-term GMI program improves the affective components of pain and shoulder flexion AROM in patients with chronic shoulder pain syndrome.

Shoulder Double Crush Syndrome: A Retrospective Study of Patients With Concomitant Suprascapular Neuropathy and Cervical Radiculopathy

Purpose

While the double crush phenomena (compression along two points on a nerve) has been established between median neuropathy and cervical radiculopathy, combined suprascapular neuropathy (SSN) and cervical C5/C6 radiculopathy-so-called shoulder double crush syndrome-has not been well examined. We aim to identify the incidence of shoulder double crush syndrome in patients undergoing arthroscopic suprascapular nerve release for SSN.

Methods

One hundred consecutive patients >18 years of age who were positive for SSN on electromyography and motor nerve conduction studies (EMG/NCS) and underwent a suprascapular nerve release were included. Patients with evidence of shoulder double crush syndrome were identified based on x ray, cervical spine magnetic resonance imaging (MRI) and examination findings. Demographics, electrodiagnostics results, treatment courses, and clinical outcomes (visual analog scores and rotator cuff strength) following arthroscopic suprascapular nerve release were compared between patients with double crush syndrome versus isolated SSN.

Results

Thirty one percent of patients had evidence of shoulder crush syndrome. Two significant electrophysiologic differences were noted in shoulder double crush patients compared to isolated SSN patients. Patients with double crush had an increased incidence of median neuropathy (51% vs 30%, P = .04). Double crush patients had less supraspinatus motor amplitude difference between the affected side and non-affected side compared to isolated SSN patients (2.62 mV vs 3.44 mV, P = .03). In general, most double crush patients were treated conservatively with regard to their cervical spine pathology.

Conclusion

A significant percentage of patients with SSN have evidence of shoulder double crush syndrome. Patients with SSN and concomitant median neuropathy should have a detailed neck examination performed.

Suprascapular nerve injury affects rotator cuff healing: A paired controlled study in a rat model

Purpose

We designed a paired controlled study to investigate the role of the suprascapular nerve (SSN) in rotator cuff healing using a rat tear model, and we hypothesised that rotator cuff healing is impaired in the absence of a healthy SSN.

Methods

Bilateral supraspinatus tenotomy from the great tuberosity was performed for 36 Wistar rats, which was then repaired immediately. A defect on the SSN was made on the right side, and a sham surgery was performed on the SSN at the left side. Twelve rats were sacrificed for biomechanical (six rats) and histological (six rats) testing, evaluated at 3, 6, and 9 weeks after surgery.

Results

The bone–tendon junction on the nerve-intact side showed significantly better biomechanical characteristics than the nerve-injured side in terms of maximum load, maximum stress over time, stiffness at 9 weeks, and Young's modulus at 3 and 9 weeks. On the nerve-injured side, significantly smaller fibrocartilage layers and muscle fibres could be obtained over time. In addition, on the nerve-injured side, inferior bone–tendon interface formation was obtained in terms of cell maturity, cell alignment, collagen orientation, and the occurrence of tidemark and Sharpey's fibres through 9 weeks. In addition, neuropeptide Y was secreted in the nerve-intact group at 6 and 9 weeks.

Conclusion

This study showed the inferior healing of the bone–tendon junction on the nerve-injured side compared with the nerve-intact side, which indicates that the SSN plays an important role in rotator cuff healing. Surgeons should pay more attention to SSN injury when treating patients with rotator cuff tear.

Risk of Revision Shoulder Surgery, Complications, and Prolonged Opioid Use in Patients Undergoing Shoulder Arthroscopy Who Have Previously Undergone Anterior Cervical Discectomy and Fusion

PURPOSE

To compare postoperative complications, rates of revision, and opioid use of those who undergo shoulder arthroscopy with and without previous anterior cervical discectomy and fusion (ACDF).

METHODS

The PearlDiver database from 2007 to 2017 was used to query all patients who underwent shoulder arthroscopy as determined by Current Procedural Terminology (CPT). Patients were then separated among those who had a previous instance of ACDF and those who did not as filtered by CPT. Postoperative complications within 30 days, readmission rates, opioid use, and revision procedures were assessed for each cohort using a mix of International Classification of Diseases Ninth and Tenth Revision Clinical Modification codes, CPT, as well as generic drug codes.

RESULTS

A total of 91,029 patients undergoing shoulder arthroscopy were identified, of whom 1,267 (1.4%) had a history of ACDF. Compared with patients without previous ACDF, patients with a history of ACDF had significantly greater respiratory complication rates (1.3% vs 0.5%: adjusted odds ratio [aOR] 2.16, 95% confidence interval [CI]1.30-3.59, P = .003), 30-day complication rates (3.7% vs 2.2%: aOR 1.48, 95% CI 1.10-1.99, P = .011), 1-year revision rates (15.2% vs 7.7%: aOR 2.00, 95% CI 1.71-2.33, P < .0001), and greater opioid use at 1 month, 3 months, 6 months, and 12 months (P < .0001).

CONCLUSIONS

This study revealed that patients who undergo shoulder arthroscopy with a history of ACDF are twice as likely to undergo revision arthroscopy within 2 years of surgery and are at an increased risk of complications within 30 days postoperatively as well as prolonged opioid use compared with those without a history of ACDF. With these findings, both spine and shoulder surgeons should aim to be more aware of surgical history, especially of the cervical spine, to better counsel patients' clinical course and expected outcomes following shoulder arthroscopy.

LEVEL OF EVIDENCE

III, retrospective cohort study.

Is there an association between metabolic syndrome and rotator cuff-related shoulder pain? A systematic review

Objectives

Rotator cuff-related shoulder pain (RCRSP) is a common upper limb complaint. It has been suggested that this condition is more common among people with cardiometabolic risk factors. This systematic review has synthesised evidence from case–control, cross-sectional and cohort studies on the association between metabolic syndrome (MetS) and RCRSP.

Design and data sources

Five medical databases (MEDLINE, EMBASE, SCOPUS, CINAHL and AMED) and reference checking methods were used to identify all relevant English articles that considered MetS and RCRSP. Studies were appraised using the Newcastle-Ottawa Scale (NOS). Two reviewers performed critical appraisal and data extraction. Narrative synthesis was performed via content analysis of statistically significant associations.

Results

Three cross-sectional, two case–control and one cohort study met the inclusion criteria, providing a total of 1187 individuals with RCRSP. Heterogeneity in methodology and RCRSP or MetS definition precluded a meaningful meta-analysis. Four of the included studies identified associations between the prevalence of MetS and RCRSP. Studies consistently identified independent cardiometabolic risk factors associated with RCRSP. All studies were level III evidence.

Summary and conclusion

The low-moderate quality evidence included in this review suggests an association between MetS and RCRSP. Most studies demonstrated moderate quality on appraisal. The direction of association and cardiometabolic factors influencing should be investigated by longitudinal and treatment studies. These preliminary conclusions and clinical utility should be treated with caution due to limitations of the evidence base.

Effect of fatigue and the absence of visual feedback on shoulder motor control in an healthy population during a reaching task

INTRODUCTION

The main role of the upper limb is to position the hand in order to carry out varied activities requiring coordinated multi-joint movement, which requires mobility and stability at the glenohumeral joint. This is made possible by the interaction between active and passive structures as well as the integration of information coming from multiple systems. This interaction can be compromised by factors such as muscle fatigue and lack of visual feedback, leading to decreased performance. Several studies have investigated their isolated effect without looking at their combined effect.

OBJECTIVE

To measure the specific and the combined effects of shoulder muscles fatigue and of lack of visual feedback on shoulder motor control during a reaching task with the arm in an elevated position.

METHODS

60 healthy participants were randomly assigned to one of four experimental groups: 1) control with visual feedback; 2) control without visual feedback; 3) fatigue with visual feedback; 4) fatigue without visual feedback. Subjects had to perform 10 trials of a reaching task in the KINARM robotic arm. Kinematic variables of interest were time taken to complete the task, final error, initial angle of deviation and area under curve. Non-parametric ANOVAs were used.

RESULTS

Analyses showed that there were statistically significant differences (p < 0,01) for the time taken to complete the task (1.15 s compared to 0.70 s), the area under the curve (0.015m² compared to 0.009m²) and the final error (0.025 m compared to 0,011 m) between those who had visual feedback and those who did not. No statistically significant fatigue or feedback X fatigue interaction effects were found for all kinematic variables.

CONCLUSION

Findings show that lack of visual feedback had an impact on the reaching task performance while fatigue did not. In addition, fatigue did not increase the effect of the lack of visual feedback.

Perspectives of participants with rotator cuff-related pain to a neuroscience-informed pain education session: an exploratory mixed method study

Purpose: To explore perceptions and initial outcomes of patients with rotator cuff-related pain to a pain education session.Materials and Methods: Ten individuals with persistent rotator cuff-related pain (≥3 months duration) attended an individual pain education session. They completed patient-reported outcomes measures on a weekly basis, three weeks prior and three weeks following the session. Individual semi-structured interviews were conducted three weeks following the pain education. Interviews were recorded, transcribed verbatim, and analyzed using the General Inductive Approach.Results: There were two over-arching key themes: firstly, 'Participants' Perspectives' of the session generated four themes: Improved understanding of 'the whole'; Mindful self-awareness; Taking charge; "The pain is still there". Their understanding of pain was reconceptualised, evident by their ability to describe the role of neurophysiological mechanisms, stress and general well-being towards their pain. The second over-arching key theme, 'Participants' Recommendations', had two themes: Integrating neuroscience with pathoanatomical knowledge and Educating other health professionals. Pain levels decreased post-pain education compared to pre-pain education.Conclusions: Following the pain education session, participants had greater understanding of factors influencing their shoulder pain. Pain education, in addition to pathoanatomical information may be useful as part of treatment for persistent rotator cuff-related pain.

The management of shoulder impingement and related disorders: A systematic review on diagnostic accuracy of physical tests and manual therapy efficacy

BACKGROUND

Diagnostic accuracy of physical tests and effectiveness of musculoskeletal rehabilitation of shoulder disorders are still debated.

OBJECTIVES

To investigate diagnostic accuracy of physical tests, efficacy of physiotherapy and coherence between target of assessment and intervention for shoulder impingement and related disorders like bursitis, rotator cuff and long head biceps tendinopathy and labral lesions.

METHODS

A systematic search of four databases was conducted, including RCTs and cross-sectional studies. Cochrane Risk of Bias and QUADAS-2 were adopted for critical appraisal and a narrative synthesis was undertaken.

RESULTS

6 RCTs and 2 cross-sectional studies were appraised. Studies presented low to moderate risk of bias. There is a lack of evidence to support the mechanical construct guiding the choice of physical tests for diagnosis of impingement. Manual techniques appear to yield better results than placebo and ultrasounds, but not better than exercise therapy alone. Discrepancy between the goal of assessment strategies and the relative proposed treatments were present together with high heterogeneity in terms of selection of patients, type of endpoints and follow-ups.

CONCLUSIONS

Musculoskeletal physiotherapy seems to be an effective treatment for patients with shoulder pain although it is still based on weak diagnostic clinical instruments. The adoption of more functional and prognostic assessment strategies is advisable to improve coherence between evaluation and treatment.

Cross-talk between shoulder and neck pain: an imaging study of association between rotator cuff tendon tears and cervical foraminal stenosis

Rotator cuff tendon tears are prevalent in patients with shoulder pain, the third most common musculoskeletal complaint. As shoulders are largely innervated by cervical nerves, it seems possible that rotator cuff pathology could have an association with cervical spine disorders, although few studies have investigated this possibility. This study aimed to explore the association between rotator cuff tendon tears and cervical radiculopathy (at C5 and C6 levels) in the shoulder pain population.We conducted a retrospective review of a clinical registry of shoulder ultrasound (US) examinations and cervical spine radiographs, recruiting a total of 126 patients with cervical spine radiographs taken within 1 year of US examinations. Foraminal stenosis was grouped into 4 categories: C4/5 intervertebral foramen only, C5/6 intervertebral foramen only, both C4/5 and C5/6 intervertebral foramina, and neither C4/5 nor C5/6 intervertebral foramen. The groups with and without rotator cuff tendon tears were compared for various factors, using the Mann-Whitney U test for continuous variables and the χ test for categorical variables. A multivariate analysis was conducted using a logistic regression model to investigate the association between rotator cuff tendon tears and cervical foraminal stenosis.Patients with rotator cuff tendon tears tended to be older and had more night-time pain. No significant association was identified between rotator cuff tendon tears and cervical foraminal stenosis at C5 and C6 levels. The only factor significantly predicting rotator cuff tendon tears was old age (odds ratio, 1.04; 95% confidence interval: 1.00-1.09).In patients with shoulder or neck pain, no significant association existed between rotator cuff tendon tears and cervical foraminal stenosis (at the C5 and C6 levels). When patients present with undifferentiated shoulder and neck pain, physicians should take a detailed history, perform physical examinations and imaging studies of both the neck and shoulder regions.

Reversal of Fatty Infiltration After Suprascapular Nerve Compression Release Is Dependent on UCP1 Expression in Mice

BACKGROUND

In large rotator cuff tears, retraction of the supraspinatus muscle creates suprascapular nerve traction and compression. However, suprascapular nerve transection, when used in previous models, is different from chronic compression of the suprascapular nerve in patients. To define the role of suprascapular nerve chronic injury in rotator cuff muscle atrophy and fatty infiltration, we developed a novel reversible suprascapular nerve compression mouse model.

QUESTIONS/PURPOSES

We asked: (1) Can suprascapular nerve injury be induced by compression but reversed after compression release? (2) Can muscle fatty infiltration be induced by suprascapular nerve compression and reversed after compression release? (3) Is white fat browning involved in fatty infiltration resorption?

METHODS

Mice in a common strain of C57BL/6J were randomly assigned to suprascapular nerve transection (n = 10), nerve compression (n = 10), nerve compression and release (n = 10), or sham control (n = 10) groups. To study the role or white fat browning on muscle fatty infiltration, additional UCP1 reporter mice (n = 4 for nerve compression and n = 4 for nerve compression release) and knockout mice (n = 4 for nerve compression and n = 4 for nerve compression release) were used. Nerve injury was testified using osmium tetroxide staining and neural muscular junction staining and then semiquantified by counting the degenerating axons and disrupted junctions. Muscle fatty infiltration was evaluated using Oil Red O staining and then semiquantified by measuring the area fraction of fat. Immunofluorescent and Oil Red O staining on UCP1 transgenic mice was conducted to testify whether white fat browning was involved in fatty infiltration resorption. Ratios of UCP1 positively stained area and fat area to muscle cross-section area were measured to semiquantify UCP1 expression and fatty infiltration in muscle by blinded reviewers. Analysis of variance with Tukey post hoc comparisons was used for statistical analysis between groups.

RESULTS

Suprascapular nerve injury was induced by compression but reversed after release. The ratios of degenerating axons were: sham control: 6% ± 3% (95% confidence interval [CI], 3%-10%); nerve compression: 58% ± 10% (95% CI, 45%-70% versus sham, p < 0.001); and nerve compression and release: 15% ± 9% (95% CI, 5%-26% versus sham, p = 0.050). The supraspinatus muscle percentage area of fatty infiltration increased after 6 weeks of nerve compression (19% ± 1%; 95% CI, 18%-20%; p < 0.001) but showed no difference after compression release for 6 weeks (5% ± 3%; 95% CI, 1%-10%; p = 0.054) compared with sham (2% ± 1%; 95% CI, 1%-3%). However, the fat area fraction in UCP1 knockout mice did not change after nerve compression release (6% ± 1%; 95% CI, 4%-8% at 2 weeks after compression and 5% ± 0.32%; 95% CI, 4%-6% after 2 weeks of release; p = 0.1095).

CONCLUSIONS

We developed a clinically relevant, reversible suprascapular nerve compression mouse model. Fatty infiltration resorption after compression release was mediated through white fat browning.

CLINICAL RELEVANCE

If the mechanism of browning of white fat in rotator cuff muscle fatty infiltration can be confirmed in humans, a UCP1 agonist may be an effective treatment for patients with suprascapular nerve injury.

Distal Mononeuropathy Before and After Arthroscopic Rotator Cuff Repair: A Prospective Investigation

PURPOSE

The purpose of this study was to characterize the occurrence of distal mononeuropathy (DMN) in patients before and after arthroscopic rotator cuff repair (RCR) as well as resolution of the symptoms.

METHODS

One hundred one patients over the age of 18 undergoing arthroscopic RCR +/- concurrent procedures completed a questionnaire regarding the presence of a symptomatic DMN. Patients with history of diabetic neuropathy, cervical radiculopathy, brachial plexopathy, or Spurling sign were excluded. All patients underwent physical examination to determine the characteristics and location of symptoms. Postoperatively, patients underwent repeat examination at 2, 6, and 12 weeks.

RESULTS

Preoperatively, 19% (19/101) of RCR patients described DMN symptoms (9 median nerve symptoms, 5 ulnar nerve symptoms, 4 nonspecific symptoms, one with both ulnar and median nerve symptoms). Ninety percent (17/19) patients with preoperative DMN symptoms described resolution within the final 12 weeks of follow-up. A portion of previously asymptomatic RCR patients (12/82) developed new DMN symptoms (6 nonspecific symptoms, 3 ulnar nerve symptoms, 2 median nerve symptoms, one radial sensory nerve symptoms) postoperatively, with 92% (11/12) having resolution by the final 12-week follow-up. At the final 12 weeks, 3 RCR patients had DMN symptoms with 2 of those 3 patients having their symptoms existing preoperatively.

CONCLUSIONS

This study supports the hypothesis that DMN can be a preexisting finding in patients undergoing arthroscopic RCR. Similarly, it is common for patients undergoing arthroscopic RCR to develop new DMN symptoms following their procedure. Regardless, there is good evidence to show that a large majority of both groups of patients will go on to have resolution of their symptoms.

LEVEL OF EVIDENCE

Level IV, prospective case series.

Shoulder Taping and Neuromuscular Control

CONTEXT

  Scapular taping can offer clinical benefit to some patients with shoulder pain; however, the underlying mechanisms are unclear. Understanding these mechanisms may guide the development of treatment strategies for managing neuromusculoskeletal shoulder conditions.

OBJECTIVE

  To examine the mechanisms underpinning the benefits of scapular taping.

DESIGN

  Descriptive laboratory study.

SETTING

  University laboratory.

PATIENTS OR OTHER PARTICIPANTS

  A total of 15 individuals (8 men, 7 women; age = 31.0 ± 12.4 years, height = 170.9 ± 7.6 cm, mass = 73.8 ± 14.4 kg) with no history of shoulder pain.

INTERVENTION(S)

  Scapular taping.

MAIN OUTCOME MEASURE(S)

  Surface electromyography (EMG) was used to assess the (1) magnitude and onset of contraction of the upper trapezius (UT), lower trapezius (LT), and serratus anterior relative to the contraction of the middle deltoid during active shoulder flexion and abduction and (2) corticomotor excitability (amplitude of motor-evoked potentials from transcranial magnetic stimulation) of these muscles at rest and during isometric abduction. Active shoulder-flexion and shoulder-abduction range of motion were also evaluated. All outcomes were measured before taping, immediately after taping, 24 hours after taping with the original tape on, and 24 hours after taping with the tape removed.

RESULTS

  Onset of contractions occurred earlier immediately after taping than before taping during abduction for the UT (34.18 ± 118.91 milliseconds and 93.95 ± 106.33 milliseconds, respectively, after middle deltoid contraction; P = .02) and during flexion for the LT (110.02 ± 109.83 milliseconds and 5.94 ± 92.35 milliseconds, respectively, before middle deltoid contraction; P = .06). These changes were not maintained 24 hours after taping. Mean motor-evoked potential onset of the middle deltoid was earlier at 24 hours after taping (tape on = 7.20 ± 4.33 milliseconds) than before taping (8.71 ± 5.24 milliseconds, P = .008). We observed no differences in peak root mean square EMG activity or corticomotor excitability of the scapular muscles among any time frames.

CONCLUSIONS

  Scapular taping was associated with the earlier onset of UT and LT contractions during shoulder abduction and flexion, respectively. Altered corticomotor excitability did not underpin earlier EMG onsets of activity after taping in this sample. Our findings suggested that the optimal time to engage in rehabilitative exercises to facilitate onset of trapezius contractions during shoulder movements may be immediately after tape application.

The role of mechanobiology in progression of rotator cuff muscle atrophy and degeneration

Rotator cuff (RC) muscles undergo several detrimental changes following mechanical unloading resulting from RC tendon tear. In this review, we highlight the pathological causes and consequences of mechanical alterations at the whole muscle, muscle fiber, and muscle resident cell level as they relate to RC disease progression. In brief, the altered mechanical loads associated with RC tear lead to architectural, structural, and compositional changes at the whole-muscle and muscle fiber level. At the cellular level, these changes equate to direct disruption of mechanobiological signaling, which is exacerbated by mechanically regulated biophysical and biochemical changes to the cellular and extra-cellular environment (also known as the stem cell "niche"). Together, these data have important implications for both pre-clinical models and clinical practice. In pre-clinical models, it is important to recapitulate both the atrophic and degenerative muscle loss found in humans using clinically relevant modes of injury. Clinically, understanding the mechanics and underlying biology of the muscle will impact both surgical decision-making and rehabilitation protocols, as interventions that may be good for atrophic muscle will have a detrimental effect on degenerating muscle, and vice versa. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:546-556, 2018.

Shoulder position sense in volleyball players with infraspinatus atrophy secondary to suprascapular nerve neuropathy

Isolated infraspinatus atrophy (IIA) is a common condition among overhead-activity athletes, which affects the hitting shoulder and is caused by suprascapular nerve injury. As the suprascapular nerve is a mixed nerve, such damage could lead to reduced afferent proprioceptive information and impaired shoulder sensorimotor control. This study aimed to evaluate the proprioception of the shoulder with IIA, through the assessment of shoulder position sense. The shoulder position sense was assessed in 24 professional volleyball players (12 players with IIA and 12 healthy players) with a blind dynamic shoulder repositioning test (all participants were blindfolded during the test). Three functional glenohumeral movements were tested as follows: abduction, forward flexion, and a combination of abduction and external rotation. In all three tested movements, the affected shoulder of players with isolated infraspinatus atrophy showed significantly higher hand position error than the healthy contralateral (P<10^-3 , for all movements) and the healthy control group hitting shoulder (P<10^-3 , for abduction and flexion; P=.02, for combined movement of abduction and external rotation). The study highlights a reduced sense of position of the hitting shoulder in professional volleyball players with IIA secondary to suprascapular nerve palsy. The higher hand position error of the pathologic shoulder suggests an impairment of the shoulder sensorimotor control system, which likely results from reduced afferent proprioceptive information. Deficient afferent proprioceptive information may result in poor accuracy in descending motor commands and impairment of the shoulder neuromuscular function, leading to reduced shoulder functional stability and increased risk of injury.