Shoulder Function and Fatty Infiltration on MRI in Older Adults During Rehabilitation for Rotator Cuff Tear

Rotator cuff tear is highly prevalent in older adults, with supraspinatus tendon tear (STT) the most common. Shoulder rehabilitation is a major treatment strategy, but supraspinatus-muscle-fatty infiltration (FI) and shoulder function in older adults with rotator cuff tear primarily managed by physical therapy (PT) is inadequately documented. We tested the hypothesis that older adults receiving usual-care PT when stratified by supraspinatus tear-status differ in supraspinatus FI [by quantitative Dixon fat fraction (FF) and semi-quantitative Goutallier grade (GG) on MRI] and shoulder function [by the American Shoulder and Elbow Surgeons score (ASES-score)] over time. Longitudinal cohort study (pilot): adults 60-85 years, PT-cohort (n=15) and control-cohort (n=25). Participants completed both shoulder MRI and ASES survey at baseline and follow-up visits. Kruskal-Wallis test compared within cohort among 3 groups: no tear (no-STT), partial-thickness tear (pt-STT), full-thickness tear (ft-STT). Mann-Whitney U test compared equivalent groups between cohorts. Baseline PT-cohort groups differed for GG (p=0.033) [no tear, 0.50±0.50;pt-STT, 1.11±0.22;ft-STT, 1.50±0.50] without difference in age, BMI, comorbidity, or ASES-score. Baseline control-cohort groups differed for FF (p=0.034) [no-tear, 5.77%±1.16%;pt-STT, 7.14%±6.26%;ft-STT, 21.44%±10.44%], without difference in age, BMI, comorbidity, or ASES-score. Baseline no-tear groups for ASES-score (p=0.049) differed between cohorts: PT-cohort (58.87±8.21) versus control-cohort (83.98±21.89). Both cohorts showed no difference in Δ-FF or Δ-GG over time. PT-cohort groups differed for Δ-ASES-score over time (p=0.042)[no-tear, 16.65±4.69;pt-STT, -7.24±0.94;ft-STT, 4.48±3.45], but control-cohort groups did not (p>0.050). Our results suggest differences exist for supraspinatus FI and self-reported shoulder function among older adults receiving PT for rotator cuff tear when stratified by supraspinatus tear-status.

Beyond the Shoulder: A Case Report of Regional Interdependence Treatment Approach in an Elite Level Tennis Player

This clinical case presents an elite level 23-year-old female tennis athlete with a high-grade partial thickness tear of the supraspinatus with associated pain, dysfunction, and deficits in strength and range of motion (ROM) of her trunk and lower extremities. The purpose was to determine the efficacy of using a regional interdependence approach in the treatment of a partial supraspinatus tear with associated kinetic chain deficits in an elite level athlete. Following 24 physical therapy sessions, pain, mobility (ROM), strength, and function improved in the dominant shoulder in addition to further symmetry of the trunk and lower extremity due to a regional interdependence rehabilitation approach and returned to elite level of play. As a result of this case, it is important for clinicians to consider a comprehensive, global approach to patient rehabilitation following injury.

Muscle Fiber Contribution to Rotator Cuff Moment Arms During Abduction for Intact Rotator Cuff, Complete Supraspinatus Tear, Superior Capsular Reconstruction, and Reverse Shoulder Arthroplasty. (225)

Objectives: The Rotator Cuff (RC) is formed from the subscapularis, supraspinatus, infraspinatus, and teres minor muscles and their tendinous extensions. The 4 RC tendons insert on the humeral head such that they contribute to the dynamic stability of the glenohumeral joint along with their rotational actions on the shoulder. The moment arm can be used to demonstrate the work effort potential that a specific muscle is contributing to a musculoskeletal joint rotation. The objective of this study was to break out RC muscles into multiple fibers, providing more clarity as to how individual fibers contribute to a muscle’s overall moment arm during abduction. The aims of this study are: 1.) to illustrate within each RC muscle how multiple muscle fiber lines of action work together to produce abduction in an intact shoulder 2.) to estimate the moment arm changes that take place when the intact rotator cuff goes through surgical repair with either SCR or RSA after complete supraspinatus tear. We hypothesized that the rotator cuff muscles work differently and in combination at the fiber level to bring about a resultant movement that can be assessed through the proposed method of moment arm calculation for intact RC, complete supraspinatus tear, SCR and RSA. Methods: Five fresh cadaveric shoulder specimens were used in an apparatus where each muscle was maintained in tension with the line of action towards its origin on the scapula (Figure 1). An Optotrack camera kept track of digitized points along both the origin and insertion of the rotator cuff muscles as the shoulder was abducted. Using these digitized points, multiple lines of action were created across the breadth of each muscle. Each muscle force action line was then used to calculate moment arm values during 0-90º abduction (Figure 2). Results: Moment arms calculated for multiple fiber lines spanning the tendon attachment site displayed the variance of fiber contribution and function within each muscle during abduction. Our results indicate that rather than providing a return to anatomical shoulder muscle function, RSA and SCR models produce moment arms that vary between muscles, with some contributing more to abduction and some contributing less. Highlighted below are the infraspinatus results for moment arms of individual fiber lines of action (Figure 3) and calculated mean moment arms (Figure 4) over abduction.ANOVA testing demonstrated a significant difference (p<0.001) when analyzing moment arms of intact, complete supraspinatus tear, SCR, and RSA models in teres minor and infraspinatus. There was no significant difference in moment arm values between the models in the subscapularis (p=0.148). Highlighted in Table 1 are the ANOVA testing results for infraspinatus. Conclusions: Our biomechanical analysis demonstrated sufficient sensitivity to detect differences in moment arms of the four rotator cuff muscles across a variety of models, suggesting changes to even one muscle of the shoulder will have significant implications on the function of other shoulder muscles. Furthermore, our analysis of fiber divisions within the same muscle illustrates the complex nature of the shoulder muscles themselves, and future studies should aim to better explore and model their function. The calculated percent differences from intact beautifully illustrated this complexity, as corrective RSA and SCR procedures provided better resemblance of intact anatomy within some rotator cuff muscles while creating a larger percent difference in other muscle groups. By breaking out RC muscles into multiple fibers, more clarity can be gained as to how individual fibers contribute to a muscle’s overall moment arm during abduction. This may further aid surgical decision-making, specifically for RSA where there is continued debate about whether to reconstruct portions of the RC. Given that the supraspinatus tendon is the most frequently torn tendon in the rotator cuff, especially for athletes who apply repetitive stress to the tendon, the results of this study may help inform post-operative rehabilitation by illustrating how abduction and stability are achieved after SCR and RSA.

Risk Factors for Supraspinatus Tears: A Meta-analysis of Observational Studies

Background: The pathogenesis of rotator cuff tears remains unclear, and there is a lack of high-quality evidence-based research on the risk factors for supraspinatus tears. Purpose: To explore 10 potential risk factors for supraspinatus muscle tears. Study Design: Systematic review; Level of evidence, 3. Methods: This review was conducted according to the MOOSE (Meta-analysis Of Observational Studies in Epidemiology) guidelines. PubMed, Embase, and Web of Science were searched for cohort, case-control and cross-sectional studies published before January 2021 on supraspinatus tears. The following potential risk factors were analyzed: age, body mass index, male sex, female sex, arm dominance, diabetes mellitus, smoking, hypertension, thyroid disease, and the critical shoulder angle (CSA). Risk ratios (RRs) or weighted mean differences (WMDs) of related risk were calculated. The Egger test was used to evaluate publication bias. Results: A total of 9 articles from 8 countries were included; among the 3240 patients, 687 were included in the supraspinatus tear group, and 2553 were included in the nonsupraspinatus tear group. The meta-analysis showed that older age (WMD, 3.36 [95% confidence interval (CI), 0.53-6.20]; P = .02), male sex (RR, 0.87 [95% CI, 0.78-0.97]; P = .01), smoking (RR, 2.21 [95% CI, 1.56-3.14]; P < .00001), diabetes (RR, 1.67 [95% CI, 1.03-2.70]; P = .04), hypertension (RR, 1.51 [95% CI, 1.16-1.97]; P = .002), and the CSA (WMD, 2.25 [95% CI, 1.39-3.12]; P < .00001) were risk factors for supraspinatus tears. Conclusion: Older age, male sex, smoking, diabetes, hypertension, and a higher CSA were found to be risk factors for supraspinatus tears in this meta-analysis review. Identifying risk factors for supraspinatus tears early can help clinicians identify these high-risk patients and choose appropriate treatments.

Outcomes Following the Repair of Isolated Supraspinatus Repairs versus those with Concurrent Subscapularis Repairs (242)

Objectives: While rotator cuff tears often require repair of the supraspinatus, patients can also have a concurrent tear of the subscapularis requiring repair. Previous smaller studies have shown good clinical outcomes following the repair of the subscapularis and rotator cuff during the same procedure.1 The purpose of this study was to compare clinical outcome measures between patients who had isolated supraspinatus repairs versus those who had a supraspinatus tear with a concurrent subscapularis repair. Methods: A retrospective review of 166 patients who underwent arthroscopic supraspinatus repair with or without a concurrent subscapularis repair between 2013-2018 with a minimum of one-year follow up was performed. Patients were separated into two groups based on their treatment: 100 had an isolated supraspinatus repair (SP) and 66 had both a supraspinatus and subscapularis repair (SB). The primary outcome was revision rotator cuff repair. Secondary outcomes were objective measures such as range of motion (ROM) and strength testing, including flexion (FF), external rotation (ER), and internal rotation (IR), as well as patient-reported outcome measures (PROs) including visual analog pain scale (VAS) and subjective shoulder value (SSV). Outcomes were compared using the Mann- Whitney Test and Fisher’s Exact Test with p<0.05, as the data were not parametric (SPSS, IBM). Results: There was no significant difference in the rate of revision surgery required following isolated supraspinatus repair versus those with a subscapularis repair. Additionally, there were no significant differences between groups for all PROs, all ROM parameters, and all strength parameters (all p > 0.05) (Table 1). Conclusions: The data from this study demonstrated that patients who require a subscapularis repair at the time of their rotator cuff repair can expect similar short term outcomes to those patients who only required repair of their supraspinatus.

Comparison of a Platelet-Rich Plasma Injection and a Conventional Steroid Injection for Pain Relief and Functional Improvement of Partial Supraspinatus Tears

Background: Partial supraspinatus tendon tears have frequently been treated using a subacromial corticosteroid injection or surgery. The clinical use of a platelet-rich plasma (PRP) injection is an alternative treatment method for the condition, despite the paucity of evidence of its efficacy. Purpose: To compare pain relief, functional improvement, and complications after an intratendinous PRP injection versus a subacromial corticosteroid injection for partial supraspinatus tears. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 32 patients with partial supraspinatus tears were randomly assigned to receive a leukocyte-poor PRP (LP-PRP) injection or a corticosteroid injection. One patient withdrew from the PRP group, leaving 15 patients in the PRP group and 16 patients in the corticosteroid group. The ultrasound-guided procedures were performed by a single experienced pain physician. Pain relief and functional improvement were evaluated using the visual analog scale (VAS) and the Oxford Shoulder Score (OSS), respectively. Treatment efficacy and complications were documented, and the 2 groups were compared at 1- and 6-month follow-up. Results: There were no differences in VAS and OSS scores between the PRP and corticosteroid groups at 1-month follow-up. However, the PRP group had better scores than the corticosteroid group had on both the VAS and OSS at 6-month follow-up (VAS: 14.5 ± 15.4 vs 37.5 ± 24.9, respectively; OSS: 16.2 ± 3.9 vs 25.0 ± 10.2, respectively; P < .01 for both). Both groups showed significant improvement in VAS and OSS scores from before treatment to 1-month follow-up (mean difference, 35.67 and 11.47 points, respectively, for the PRP group; mean difference, 29.69 and 11.13 points, respectively, for the corticosteroid group; P < .01 for all). The VAS and OSS scores did not change significantly at 6-month follow-up in the corticosteroid group; however, the PRP group showed continued improvement in both VAS and OSS scores between 1- and 6-month follow-up (mean difference, 15.87 and 7.40 points, respectively; P < .01 for both). There were no complications in either group. Conclusion: An injection using either a corticosteroid or LP-PRP resulted in a similar reduction in pain and improvement in function at 1 month in patients with a partial supraspinatus tear. However, PRP showed superior benefits over the corticosteroid at 6-month follow-up.

Correlation between full-thickness degenerative supraspinatus tear and radiographic parameters including the acromiohumeral centre edge angle and the greater tuberosity angle

Background Many radiographic parameters associated with the extrinsic cause of supraspinatus tears have been proposed. The aim of this study was to assess the relationship between a full-thickness degenerative supraspinatus tear (FTDST) and the patient’s radiographic parameters, including the acromiohumeral centre edge angle (ACEA) and the greater tuberosity angle (GTA). Methods A retrospective study was conducted. We included 116 patients who underwent shoulder arthroscopic surgery at our institute. The case group included FTDST patients, whereas the control group also included patients without evidence of supraspinatus tears. In each patient, the ACEA and GTA values were measured and analyzed by two independent observers. Intra- and interobserver reliabilities were assessed. Multivariate regression analysis was performed. Results The ACEA values were significantly increased in the FTDST group with a mean of 26.44° ± 9.83° compared with 16.81° ± 7.72° in the control group (P < 0.001). Multivariate regression analysis also showed that higher ACEA values were associated with an FTDST (odds ratio 1.16 per degree, P = 0.01). For GTA values, a statistically significant difference was found with a mean of 70.92° ± 6.64 compared with 67.84° ± 5.56 in the control group (P = 0.02). However, stepwise regression analysis did not indicate that GTA was a predictor of FTDST. Conclusions Our study demonstrated that the presence of increased ACEA values is an independent significant risk factor for the presence of FTDSTs. Consequently, GTA values may be less helpful in assessing the risk of FTDST, especially in this specific population.