Evaluation of the Relationship between Acromiohumeral Distance and Supraspinatus Tendon Thickness Measured by Ultrasonography and Rotator Cuff Pathologies, Pain, and Function.

PURPOSE OF THE STUDY: In this study, we aimed to evaluate acromiohumeral distance (AHD) and supraspinatus tendon (ST) thickness measurements and their relationship with pain and function in ST pathologies. MATERIAL AND METHODS: The study included 111 patients and 25 healthy controls (HC). Patients were divided into 3 groups according to their diagnosis: non-tear tendinopathy (NTT), partial thickness tear (PTT), and full thickness tear (FTT). The AHD and ST thickness of the participants were measured with ultrasound. The pain and functional status of the patients were evaluated with the Numeric Rating Scale (NRS), The QuickDASH shortened version of the DASH Outcome Measure - Disabilities of the Arm Shoulder and Hand (QDASH), and Simple Shoulder Test (SST). RESULTS: The AHD value was significantly higher in the NTT group (p=0.000). The AHD value was significantly lower in the FTT group (p=0.000). ST thickness value was significantly lower in the PTT group compared to the NTT group (p=0.000). There was a positive correlation between ST thickness and BMI (r=0.553,p<0.01). There was a negative correlation between ST thickness and SST and a positive correlation between ST thickness (r=-0.223,p<0.05) and QDASH (r=0.276,p<0.05). CONCLUSIONS: We found that AHD and SST thicknesses significantly differed in the NTT, PTT, FTT, and HC groups. This difference may be important for diagnosis. In addition, the effect of obesity on ST thickness and the relationship between ST thickness and functional scores may be considered. Weight control may be effective at this point. KEY WORDS: acromiohumeral distance, supraspinatus tendon thickness, ultrasound.

Shoulder mobility and strength impairments in patients with rotator cuff related shoulder pain: a systematic review and meta analysis.

Background: The methods previously proposed in the literature to assess patients with rotator cuff related shoulder pain, based on special orthopedic tests to precisely identify the structure causing the shoulder symptoms have been recently challenged. This opens the possibility of a different way of physical examination. Objective: To analyze the differences in shoulder range of motion, strength and thoracic kyphosis between rotator cuff related shoulder pain patients and an asymptomatic group. Method: The protocol of the present research was registered in the International Prospective Register of Systematic Review (PROSPERO) (registration number CRD42021258924). Database search of observational studies was conducted in MEDLINE, EMBASE, WOS and CINHAL until July 2023, which assessed shoulder or neck neuro-musculoskeletal non-invasive physical examination compared to an asymptomatic group. Two investigators assessed eligibility and study quality. The Newcastle Ottawa Scale was used to evaluate the methodology quality. Results: Eight studies (N = 604) were selected for the quantitative analysis. Meta-analysis showed statistical differences with large effect for shoulder flexion (I2 = 91.7%, p < 0.01, HG = -1.30), external rotation (I2 = 83.2%, p < 0.01, HG = -1.16) and internal rotation range of motion (I2 = 0%, p < 0.01, HG = -1.32). Regarding to shoulder strength; only internal rotation strength showed statistical differences with small effect (I2 = 42.8%, p < 0.05, HG = -0.3). Conclusions: There is moderate to strong evidence that patients with rotator cuff related shoulder pain present less shoulder flexion, internal and external rotation range of motion and less internal rotation strength than asymptomatic individuals.

Factors determining the short-term clinical outcomes of conservative treatment in patients with supraspinatus tear.

INTRODUCTION: To identify factors influencing the better and worse changes in the Western Ontario Rotator Cuff Index of patients undergoing conservative treatment for supraspinatus tendon tear. METHODS: The study included 30 patients with supraspinatus tendon tear who underwent conservative treatment. The average duration of intervention was 35.4 days. The Western Ontario Rotator Cuff Index, shoulder range of motion, isometric muscle strength, supraspinatus tendon thickness, thickness of the supraspinatus, infraspinatus, and teres minor muscles, and acromiohumeral interval were assessed before and after the intervention. In the statistical analyses, change in the Western Ontario Rotator Cuff Index was the dependent variable, and the amount of change in each measurement variable before and after the intervention was the independent variable. RESULTS: The average Western Ontario Rotator Cuff Index improved from 1067 at pre-treatment to 997 at post-treatment, but without a significant difference (p = 0.29). A multiple regression analysis revealed that supraspinatus tendon thickness and muscle strength in shoulder external rotation at 90° scaption had a significant effect on the change in the Western Ontario Rotator Cuff Index (R2 = 0.44, p < 0.01). CONCLUSION: Supraspinatus tendon thickness and muscle strength in shoulder external rotation at 90° scaption were important factors for the Western Ontario Rotator Cuff Index score in the early stages of conservative treatment for patients with supraspinatus tendon tear.

The Subscapularis Healing Index: A New Scoring System for Predicting Subscapularis Healing After Arthroscopic Repair.

BACKGROUND: Previous research has emphasized the effect of prognostic factors on arthroscopic rotator cuff repair (ARCR) success, but a specific focus on subscapularis (SSC) tendon repair healing is lacking. PURPOSE: To identify prognostic factors for SSC healing after ARCR and develop the Subscapularis Healing Index (SSC-HI) by incorporating these factors. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: This was a retrospective study using prospectively maintained data collected from patients with isolated or combined SSC tears who underwent ARCR between 2011 and 2021 at a single institution with a minimum 2-year follow-up. Functional outcomes were assessed using the American Shoulder and Elbow Surgeons (ASES) score, Subjective Shoulder Value (SSV), and visual analog scale (VAS) pain scale. SSC tendon healing was evaluated via ultrasound at the final follow-up. Multivariate logistic regression analysis was performed to determine the factors affecting SSC healing, and based on these factors, the SSC-HI, which ranges from 0 to 15 points, was developed using odds ratios (ORs). RESULTS: Among 1018 ARCR patients, 931 met the inclusion criteria; 279 returned voluntarily for postoperative SSC ultrasound assessment. The overall healing failure rate was 10.8% (30/279). Risk factors for healing failure included female sex (P = .008; OR, 3.119), body mass index (BMI) ≥30 (P = .053; OR, 2.323), supraspinatus fatty infiltration ≥3 (P = .033; OR, 3.211), lower SSC fatty infiltration ≥2 (P = .037; OR, 3.608), and Lafosse classification ≥3 (P = .007; OR, 3.224). A 15-point scoring system comprised the following: 3 points for female sex, 2 points for BMI ≥30, 3 points for supraspinatus fatty infiltration ≥3, 4 points for lower SSC fatty infiltration ≥2, and 3 points for Lafosse classification ≥3. Patients with ≤4 points had a 4% healing failure rate, while those with ≥9 points had a 55% rate of healing failure. Patients with a healed SSC reported significantly higher ASES (healed SSC: ΔASES, 44.7; unhealed SSC: ΔASES, 29; P < .01) and SSV (healed SSC: ΔSSV, 52.9; unhealed SSC: ΔSSV, 27.5; P < .01) and lower VAS (healed SSC: ΔVAS, -4.2; unhealed SSC: ΔVAS, -3; P < .01) scores compared with those with an unhealed SSC. CONCLUSION: The SSC-HI scoring system integrates clinical and radiological factors to predict SSC healing after surgical repair. Successful SSC healing was found to be associated with enhanced functional outcomes, underscoring the clinical relevance of SSC healing prediction in the management of these tears.

Skilled reaching test for shoulder function assessment in a rat model of rotator cuff tear: a pilot study.

BACKGROUND: Functional assessments are crucial to evaluate treatment outcomes in clinical and animal studies on rotator cuff injuries. While gait analysis is commonly used to assess animal models of rotator cuff tears, it is less relevant for human patients as the human shoulder is typically assessed in a non-weight-bearing condition. The present study introduces the skilled reaching test as a shoulder functional assessment tool for rats, which allows for evaluation without weight bearing. METHODS: In the control group, 8 male Sprague-Dawley rats received rotator cuff tear surgery without repair. In the rotator cuff repair group, 20 rats received rotator cuff repair at 4 weeks post rotator cuff tear. For the skilled reaching test, rats were trained to extend their forelimbs to fetch food pellets, and the number of trials, number of attempts and the success rate were recorded. The gait analysis and skilled reaching test were performed at baseline, 4 weeks post-tear, 1, 2, 4, and 8 weeks post-repair. The repeated measures analysis of variance was used to evaluate the effects of time on the shoulder function. The significance level was set at 0.05. RESULTS: The skilled reaching test required 216 h to conduct, while the gait analysis took 44 h. In the rotator cuff repair group, gait performance significantly deteriorated at 1 week post-repair and restored to 4 weeks post-tear levels at 4 weeks post-repair. Regarding the skilled reaching test, the number of attempts, number of trials and the success rate decreased at 1 week post-repair. Subsequently, there was a brief rebound in performance observed at 2 weeks post-repair, followed by a continued decline in the number of attempts and trials. By 8 weeks post-repair, only the success rate had restored to levels similar to those observed at 4 weeks post-tear. CONCLUSION: The skilled reaching test can detect functional deficiencies following rotator cuff tear and repair, while it requires high time and labour costs.

Tuberoplasty reduces resistance force in dynamic shoulder abduction for irreparable rotator cuff tears: a cadaveric biomechanical study.

BACKGROUND: Arthroscopic tuberoplasty is an optional technique for managing irreparable rotator cuff tears. However, there is a lack of studies investigating the resistance force during shoulder abduction in cases of irreparable rotator cuff tears and tuberoplasty. HYPOTHESES: In shoulders with irreparable rotator cuff tears, impingement between the greater tuberosity (GT) and acromion increases the resistance force during dynamic shoulder abduction. Tuberoplasty is hypothesized to reduce this resistance force by mitigating impingement. STUDY DESIGN: Controlled laboratory study. METHODS: Eight cadaveric shoulders, with a mean age of 67.75 years (range, 63-72 years), were utilized. The testing sequence included intact rotator cuff condition, irreparable rotator cuff tears (IRCTs), burnishing tuberoplasty, and prosthesis tuberoplasty. Burnishing tuberoplasty refers to the process wherein osteophytes on the GT are removed using a bur, and the GT is subsequently trimmed to create a rounded surface that maintains continuity with the humeral head. Deltoid forces and actuator distances were recorded. The relationship between deltoid forces and actuator distance was graphically represented in an ascending curve. Data were collected at five points within each motion cycle, corresponding to actuator distances of 20 mm, 30 mm, 40 mm, 50 mm, and 60 mm. RESULTS: In the intact rotator cuff condition, resistance forces at the five points were 34.25 ± 7.73 N, 53.75 ± 7.44 N, 82.50 ± 14.88 N, 136.25 ± 30.21 N, and 203.75 ± 30.68 N. In the IRCT testing cycle, resistance forces were 46.13 ± 7.72 N, 63.75 ± 10.61 N, 101.25 ± 9.91 N, 152.5 ± 21.21 N, and 231.25 ± 40.16 N. Burnishing tuberoplasty resulted in resistance forces of 32.25 ± 3.54 N, 51.25 ± 3.54 N, 75.00 ± 10.69 N, 115.00 ± 10.69 N, and 183.75 ± 25.04 N. Prosthesis tuberoplasty showed resistance forces of 29.88 ± 1.55 N, 49.88 ± 1.36 N, 73.75 ± 7.44 N, 112.50 ± 7.07 N, and 182.50 ± 19.09 N. Both forms of tuberoplasty significantly reduced resistance force compared to IRCTs. Prosthesis tuberoplasty further decreased resistance force due to a smooth surface, although the difference was not significant compared to burnishing tuberoplasty. CONCLUSION: Tuberoplasty effectively reduces resistance force during dynamic shoulder abduction in irreparable rotator cuff tears. Prosthesis tuberoplasty does not offer a significant advantage over burnishing tuberoplasty in reducing resistance force. CLINICAL RELEVANCE: Tuberoplasty has the potential to decrease impingement, subsequently reducing resistance force during dynamic shoulder abduction, which may be beneficial in addressing conditions like pseudoparalysis.

Current research trends on the effect of diabetes mellitus on rotator cuff tendon healing/tendinopathy.

Rotator cuff tendon tears are a leading cause of shoulder pain. They are challenging to treat, and tendon-bone healing has a high failure rate despite successful surgery. Tendons connect the muscles and bones, which make them important for the body's overall mobility and stability. Metabolic diseases, including diabetes or high blood pressure, can affect the healing process after repair of a damaged tendon. With a global incidence of 9.3%, diabetes is considered as a significant risk factor for rotator cuff tendon healing because it causes structural, inflammatory, and vascular changes in the tendon. However, the mechanisms of how diabetes affects tendon healing remain unknown. Several factors have been suggested, including glycation product accumulation, adipokine dysregulation, increased levels of reactive oxygen species, apoptosis, inflammatory cytokines, imbalanced matrix-metalloproteinase-to-tissue-inhibitor ratio, and impaired angiogenesis and differentiation of the tendon sheath. Despite the effects of diabetes on tendon function and healing, few treatments are available to improve recovery in these patients. This review summarizes the current literature on the pathophysiological changes of the tendon in diabetes and hyperlipidemia. Preclinical and clinical evidence regarding the association between diabetes and tendon healing is presented. Moreover, current approaches to improve tendon healing in patients with diabetes are reviewed.

Effect of extracorporeal shockwave therapy for rotator cuff tendinopathy: a systematic review and meta-analysis.

BACKGROUND: Rotator cuff tendinopathy (RCT) is a widespread musculoskeletal disorder and a primary cause of shoulder pain and limited function. The resulting pain and limited functionality have a detrimental impact on the overall quality of life. The purpose of this study was to perform a systematic review of the effects of extracorporeal shock wave therapy (ESWT) for RCT. METHODS: The literature search was conducted on the following databases from inception to February 20, 2024: PubMed, Web of Science, the Cochrane Library, Scopus, MEDLINE, EMBASE, EBSCO, and China National Knowledge Infrastructure (CNKI) were checked to identify the potential studies exploring the effect of ESWT for the treatment of Rotator cuff tendinopathy (Calcification or non-calcification), control group for sham, other treatments (including placebo), without restriction of date, language. Two researchers independently screened literature, extracted data, evaluated the risk of bias in the included studies, and performed meta-analysis using RevMan 5.3 software. RESULTS: A total of 16 RCTs with 1093 patients were included. The results showed that compared with the control group, ESWT for pain score Visual Analogue Scale/Score (VAS) (SMD = -1.95, 95% CI -2.47, -1.41, P < 0.00001), function score Constant-Murley score (CMS) (SMD = 1.30, 95% CI 0.67, 1.92, P < 0.00001), University of California Los Angeles score (UCLA) (SMD = 2.69, 95% CI 1.64, 3.74, P < 0.00001), American Shoulder and Elbow Surgeons form (ASES) (SMD = 1.29, 95% CI 0.93, 1.65, P < 0.00001), Range of motion (ROM) External rotation (SMD = 1.00, 95% CI 0.29, 1.72, P = 0.02), Total effective rate (TER) (OR = 3.64, 95% CI 1.85, 7.14, P = 0.0002), the differences in the above results were statistically significant. But ROM-Abduction (SMD = 0.72, 95% CI -0.22, 1.66, P = 0.13), the difference was not statistically significant. CONCLUSION: Currently limited evidence suggests that, compared with the control group, ESWT can provide better pain relief, functional recovery, and maintenance of function in patients with RCT.

The Fate of the Shoulder Post Rotator Cuff Repair: Biomechanical Properties of the Supraspinatus Tendon and Surrounding Structures.

The study aimed to describe the changes in biomechanical properties of the supraspinatus tendon, deltoid muscle, and humeral head post arthroscopic rotator cuff repair using shear wave elastography. Shear wave velocity of the tendon, deltoid, and humeral head of 48 patients was measured at predetermined sites at 1 week, 6 weeks, 12 weeks, 6 months, and 12 months post repair. One-way ANOVA with Tukey's correction and Spearman's correlation were performed. Mean±SEM healing tendon stiffness, adjacent to tendon footprint, increased from 1 week (6.2±0.2 m/s) to 6 months (7.5±0.3 m/s) and 12 months (7.8±0.3 m/s) (P<0.001). Mean±SEM deltoid muscle stiffness was higher at 12 months (4.1±0.2 m/s) compared to 1 week (3.4±0.1 m/s) and 12 weeks (3.5±0.1 m/s) (P<0.05). Humeral head stiffness did not change. Following arthroscopic rotator cuff repair, supraspinatus tendon stiffness increased in a curvilinear fashion over 6 months. From 6 months, deltoid muscle stiffness increased, corresponding to when patients were instructed to return to normal activities.

The effect of video-assisted training on upper extremity problems and functions after rotator cuff repair: a randomized controlled trial.

Background/aim: The shoulder is the most mobile joint in the body, and is frequently exposed to injuries. The applied surgical treatments, protection of the shoulder after surgery, care in the use of the shoulder in activities of daily living (ADLs) and gradual exercise programs are all vital to the recovery process. The present study investigates the effect of video-assisted training (VAT) on upper extremity complications and functions after rotator cuff repair (RCR). Materials and method: Included in this prospective, parallel two-armed, randomized controlled study were an experimental group (n: 24) that received VAT detailing early postoperative care for RCR and instructions on performing ADLs, and that had access to a 90-day gradual exercise program, and a control group (n: 24) that received routine care. The primary outcomes were upper extremity problems and functions, as assessed by the Disabilities of the Arm, Shoulder and Hand (DASH) and modified Constant-Murley scores (MCM), while secondary outcomes were complications that had developed within the past three months. The outcomes were measured at baseline, after six weeks and at three months. Results: After 3 months, a statistically significant difference was noted in the DASH-Work (p = 0.001) and MCM ADLs scores (p = 0.003) of the two groups, and significant changes in which the scale scores of both groups when compared to the initial measurement. Only one patient in the VAT group developed complications after RCR at one month; there were no significant differences in the complications of the two groups (p = 0.235). Conclusion: VAT can increase function in RCR patients. Healthcare professionals, especially nurses, can use the VAT method to improve shoulder function in patients after RCR.

Preoperative handgrip strength can predict early postoperative shoulder function in patients undergoing arthroscopic rotator cuff repair.

BACKGROUND: Rotator cuff tears (RCTs) are a common musculoskeletal disorder, and arthroscopic rotator cuff repair (ARCR) is widely performed for tendon repair. Handgrip strength correlates with rotator cuff function; however, whether preoperative grip strength can predict functional outcomes in patients undergoing ARCR remains unknown. This study aimed to investigate the correlation between preoperative grip strength and postoperative shoulder function following ARCR. METHODS: A total of 52 patients with full-thickness repairable RCTs were prospectively enrolled. Baseline parameters, namely patient characteristics and intraoperative findings, were included for analysis. Postoperative shoulder functional outcomes were assessed using the Quick Disabilities of the Arm, Shoulder, and Hand (QDASH) questionnaire and Constant-Murley scores (CMSs). Patients were followed up and evaluated at three and six months after ARCR. The effects of baseline parameters on postoperative outcomes were measured using generalized estimating equations. RESULTS: At three and six months postoperatively, all clinical outcomes evaluated exhibited significant improvement from baseline following ARCR. Within 6 months postoperatively, higher preoperative grip strength was significantly correlated with higher CMSs (ß = 0.470, p = 0.022), whereas increased numbers of total suture anchors were significantly correlated with decreased CMSs (ß = - 4.361, p = 0.03). Higher body mass index was significantly correlated with higher postoperative QDASH scores (ß = 1.561, p = 0.03) during follow-up. CONCLUSIONS: Higher baseline grip strength predicts more favorable postoperative shoulder function following ARCR. A preoperative grip strength test in orthopedic clinics may serve as a predictor for postoperative shoulder functional recovery in patients undergoing ARCR.

Assessment of description and implementation fidelity of clinical trials involving exercise-based treatment in individuals with rotator cuff tears: a scoping review.

BACKGROUND: For evidence-based practice, clinicians and researchers can rely on well-conducted randomized clinical trials that exhibit good methodological quality, provide adequate intervention descriptions, and implementation fidelity. OBJECTIVE: To assess the description and implementation fidelity of exercise-based interventions in clinical trials for individuals with rotator cuff tears. METHODS: A systematic search was conducted in PubMed, Embase, CINAHL, LILACS, Cochrane Library, Web of Science, SCOPUS and SciELO. Randomized clinical trials that assessed individuals with rotator cuff tears confirmed by imaging exam were included. All individuals must have received an exercise-based treatment. The methodological quality was scored with the Physiotherapy Evidence Database (PEDro) scale. The Template for Intervention Description and Replication (TIDieR) checklist and the National Institutes of Health Behaviour Change Consortium (NIHBCC) were used to assess intervention description and implementation fidelity, respectively. RESULTS: A total of 13 studies were included. Despite their adequate methodological quality, the description of the intervention was poor with TIDieR scores ranging from 6 to 15 out of 24 total points. The TIDieR highest-scoring item was item 1 (brief name) that was reported in all studies. Considering fidelity, only one of the five domains of NIHBCC (i.e., treatment design) reached just over 50%. CONCLUSION: Exercise-based interventions used in studies for individuals with rotator cuff tears are poorly reported. The description and fidelity of the intervention need to be better reported to assist clinical decision-making and support evidence-based practice.

Relationship between pain and proprioception among individuals with rotator cuff-related shoulder pain.

BACKGROUND: Individuals with rotator cuff-related shoulder pain (RCRSP) have altered proprioception. The relationship between shoulder pain and proprioception is not well understood. PURPOSE: This study aimed to investigate the relationship between shoulder pain and proprioception. STUDY DESIGN: This was a cross-sectional comparative study. METHODS: Twenty-two participants with RCRSP (mean age 27.6 ± 4.8 years) and 22 matched pain-free participants (23.4 ± 2.5 years) performed two upper limb active joint position sense tests: (1) the Upper Limb Proprioception Reaching Test (PRO-Reach; reaching toward seven targets) in centimeters and (2) Biodex System at 90% of maximum internal rotation in degrees. Participants performed three memorization and three reproduction trials blindfolded. The proprioception error (PE) is the difference between the memorized and estimation trials. Pain levels were captured pre- and post-evaluation (11-point Likert Numerical Pain Rating Scale). Relationships between PE and pain were investigated using independent t-tests and Spearman rank correlations. RESULTS: Overall, 22.7% RCRSP participants indicated an increase in pain following the PRO-Reach (X̅ increase of 1.4 ± 1.5 points), while 59% did so with the Biodex (X̅ increase of 2.3 ± 1.8 points), reflecting a clinically important increase in pain. Weak-to-moderate correlations between pain and PEs were found with the Biodex (r = 0.39-0.53) and weak correlations with the PRO-Reach (r = -0.26 to 0.38). Concerning PEs, no significant differences were found between groups with the Biodex (p = 0.32, effect size d = -0.31 [-0.90 to 0.29]). The RCRSP participants demonstrated lower PEs with the PRO-Reach in elevation compared to pain-free participants (global X̅ = 4.6 ± 1.2 cm vs 5.5 ± 1.5 cm; superior 3.8 ± 2.1 cm vs 5.7 ± 2.9 cm; superior-lateral nondominant targets 4.3 ± 2.2 cm vs 6.1 ± 2.8 cm; p = 0.02-0.05, effect size d = 0.72-0.74 [0.12-1.3]). CONCLUSIONS: Individuals with RCRSP demonstrated better upper limb proprioception in elevation, suggesting a change to interoception (sensory reweighting) in the presence of pain.

Subscapularis impairment on magnetic resonance imaging is correlated with functional limitations in neonatal brachial plexus palsy.

PURPOSE: The relationship between functional shoulder deficits in children with neonatal brachial plexus palsy (NBPP) and magnetic resonance imaging (MRI) shoulder abnormalities was evaluated. METHODS: Shoulder function was assessed in 16 children (mean age: 5.8 years; range: 3-12 years) with NBPP based on shoulder rotator muscle strength, as measured using an isokinetic dynamometer and the modified Mallet score. The thickness and fatty infiltration of the subscapularis and infraspinatus muscles, and the morphology of the glenoid on MRI, were also determined. RESULTS: The highest subscapularis fatty infiltration subgroup of NBPP patients promoted the highest alteration muscle thickness and modified Mallet score. CONCLUSIONS: In NBPP children, subscapularis impairments play a major role in the functional limitations. This study of pediatric NBPP patients highlighted the value of adding an examination of the muscles to routine MRI assessment of bone parameters in the shoulders of NBPP children. TRIAL REGISTRATION: NCT03440658.

Incidence and risk factors for early postoperative stiffness after arthroscopic rotator cuff repair in patients without preoperative stiffness.

The purpose of this study was to investigate the incidence and risk factors of early postoperative stiffness in patients without preoperative stiffness undergoing isolated arthroscopic rotator cuff repair (ARCR). Two hundred seventy-four patients who underwent primary ARCR were included. At 3 months after surgery, criteria for shoulder stiffness was set as follows: (1) passive forward flexion < 120˚, or (2) external rotation at side < 30˚. Patients with preoperative stiffness or who underwent additional procedures were excluded. Patients-related, radiological (muscle atrophy and fatty infiltration), and intraoperative (tear size, repair techniques, number of anchors used, and synovitis scores) risk factors were analyzed. Univariate and multivariate analyses were used to identify risk factors for postoperative stiffness. Thirty-nine of 274 patients (14.2%) who underwent ARCR developed postoperative stiffness. Univariate analyses revealed that early postoperative stiffness was significantly associated with diabetes mellitus (p = 0.030). However, radiological and intraoperative factors did not affect postoperative shoulder stiffness (all p > 0.05). Multivariate analyses revealed early postoperative stiffness was significantly associated with diabetes mellitus and timing of rehabilitation (p = 0.024, p = 0.033, respectively). The overall incidence of early postoperative stiffness following isolated ARCR in patients without preoperative stiffness was 14.2%. Diabetes mellitus and timing of rehabilitation were independent risk factors for early postoperative stiffness following ARCR.

Study on the effects of arm abduction angle and cushion support during sonographic examination on the stiffness of supraspinatus muscle of sonographers using shear wave elastography.

OBJECTIVES: The incidence of work-related musculoskeletal disorder remains high in sonography. The aims of this study are to determine the changes in muscle stiffness with different arm abduction angles, and to investigate the effect of cushion support on reducing muscle load in the supraspinatus when sonographers scan with the arm abducted to different angles. METHODS: This is a prospective crossover study. Twenty-three healthy female subjects aged between 20 and 23 years were included. Subjects were instructed to simulate performing standardized abdominal ultrasound scans. The changes in muscle stiffness of supraspinatus, measured as shear modulus, at rest and at 30°, 45°, and 60° arm abduction angles with and without cushion support were evaluated using shear-wave elastography. Styrofoam support was used for the cushion support. RESULTS: Mean shear moduli of supraspinatus were 27.77 ± 5.84 kPa at rest and 41.63 ± 7.09 kPa, 63.88 ± 14.43 kPa, and 89.76 ± 16.55 kPa for 30°, 45°, and 60° arm abduction respectively, which corresponds to 53%, 116% increase in muscle stiffness when scanning arm abducted from 30° to 45° and 60° (p < .001). After applying cushion support, shear moduli dropped to 24.04 ± 5.60 kPa, 31.98 ± 6.06 kPa, 37.47 ± 5.61 kPa for arm abducted to 30°, 45°, and 60° respectively (p < .001). The muscle stiffnesses between 30° abduction without support and 60° abduction with support had no significant difference (p > .05). CONCLUSIONS: Muscle stiffness of supraspinatus increased with increasing arm abduction angle during ultrasound scanning. Utilizing cushion support underneath the arm was effective in reducing muscle stiffness in supraspinatus. Our results provide scientific justification on postural modifications for sonographers.

Injection of Micronized Human Amnion/Chorion Membrane Results in Increased Early Supraspinatus Muscle Regeneration in a Chronic Model of Rotator Cuff Tear.

Surgical repair of severe rotator cuff tear often results in retear due to unaddressed muscle degeneration. The objective of this study was to test the regenerative potential of micronized dehydrated Human Amnion/Chorion Membrane (dHACM), in a clinically relevant delayed reattachment model of rotator cuff repair. Micronized dHACM was injected into rat supraspinatus muscle during tendon re-attachment surgery, three weeks after original tendon injury. One week after material injection, inflammatory and mesenchymal stem cell infiltration into supraspinatus muscles was assessed via flow cytometry. Histological methods were utilized to assess structural and regenerative changes in muscle one and three weeks after material injection. Micronized dHACM injection resulted in increased M1-like macrophages (17.1 [Formula: see text] fold change over contralateral controls) and regenerating muscle fibers (4.3% vs 1.7% in saline treated muscles) one week after injection compared to saline treated muscles. Tendon reattachment itself exhibited intrinsic healing in this model, demonstrated by a general return of muscle weight and reduced fibrosis. Our results indicate that injection of micronized dHACM may initiate an inflammatory response in degenerated muscle that promotes early muscle regeneration, and that our animal model may be a suitable platform for studying treatments in muscle at early timepoints, before intrinsic healing occurs.

Corticosteroids or platelet-rich plasma injections for rotator cuff tendinopathy: a randomized clinical trial study.

BACKGROUND: Studies evaluating the role of both corticosteroids and platelet-rich plasma (PRP) in the treatment of rotator cuff (RC) tendinopathies have been contradicting. We compared structural and clinical changes in RC muscles after corticosteroids and PRP injections. METHODS: This is a randomized double-blind clinical trial. All individuals with diagnosis of RC tendinitis during 2014-2017 were considered. Individuals were randomly allocated to either receive PRP or corticosteroids. Overall, 3cc of PRP was injected within the subacromial joint and another 3cc was injected at the site of the tendon tear, under the guide of sonography. For the corticosteroid group, 1cc of Depo-medrol 40mg and 1cc of lidocaine (2%) was injected within the subacromial joint. RESULTS: Overall, 58 patients entered the study. Comparison of pain, range of motion (ROM), Western Ontario RC (WORC), Disability of Arm-Hand-Shoulder (DASH) scores, and supraspinatus thickness showed significant improvement during follow-ups in both groups (p<0.05). During 3 months of follow-up, pain improvement was significantly better within the PRP group during (from 6.66±2.26 to 3.08±2.14 and 5.53±1.80 to 3.88±1.99, respectively; p=0.023). Regarding ROM, the PRP group had significant improvement in adduction (20.50°±8.23° to 28°±3.61° and 23.21°±7.09° to 28.46°±4.18° for the PRP and corticosteroid groups, respectively; p=0.011) and external rotation (59.66°±23.81° to 76.66°±18.30° and 57.14°±24.69° to 65.57°±26.39°, for the PRP and corticosteroid groups, respectively; p=0.036) compared to the corticosteroid group. CONCLUSION: We found that PRP renders similar results to that of corticosteroids in most clinical aspects among patients with RC tendinopathies; however, pain and ROM may show more significant improvement with the use of PRP. Considering that the use of corticosteroids may be contraindicated in some patients and may be associated with the risk of tendon rupture, we suggest the use of PRP in place of corticosteroid-based injections among patients with RC tendinopathy. TRIAL REGISTRATION: Clinical trial registration code: IRCT201302174251N9.

Rotator cuff anchor repair: Histological changes associated with the recovering mechanical properties in a rabbit model.

Rotator cuff anchor repair is an increasingly common surgical procedure but the failure rate remains high. In order to improve surgical outcomes, a better understanding of postrepair histological and cellular responses at the tendon-bone attachment site (enthesis) is needed. We examined operated shoulders from 42 New Zealand female white rabbits. The animals underwent unilateral supraspinatus detachment followed by anchor repair a week later. To assess enthesis reformation, fibrocartilage staining area and the number of chondrocytes or nonchondrocytes were quantified at 0, 1, 2, and 4 weeks postrepair. Using linear regression, we correlated these results with the load to failure and stiffness recorded during mechanical testing of the tendons. Fibrocartilage staining and chondrocyte number increased during the first 2 weeks of enthesis formation. Between 2 and 4 weeks, fibrocartilage staining plateaued while chondrocyte number decreased. The presence of nonchondrocytes remained similar between 0- and 1-week postrepair but then decreased abruptly at 2 weeks. There was a linear correlation between fibrocartilage staining area and load to failure as well as stiffness. Nonchondrocyte number negatively correlated with stiffness. Early plateau of fibrocartilage staining and decrease in chondrocytes between 2 and 4 weeks postrepair suggest a blunted enthesis formation response in our animal model.