Active Shoulder Research Articles

Multicentre randomised controlled trial comparing Bankart repair with remplissage and Latarjet procedure in shoulder instability with subcritical bone loss (STABLE): study protocol

IntroductionRecurrent shoulder dislocations often cause attrition of the labrum and progressive loss of the anterior bony contour of the glenoid. Treatment options for this pathology involve either soft tissue repair...

Prior Shoulder Arthroscopy is Associated with Inferior Clinical Outcomes Following Primary Reverse Shoulder Arthroplasty for Rotator Cuff Tear Arthropathy

Background Various patient-related and condition-related factors can influence the clinical benefits of reverse shoulder arthroplasty (RSA). With the emergence of new potential joint-preserving arthroscopic interventions, understanding the impact of shoulder arthroscopy prior to RSA is increasingly relevant. Therefore, the purpose of this study was to understand the impact of previous ipsilateral shoulder arthroscopy on outcomes and shoulder function following RSA for rotator cuff tear arthropathy. Methods Patients who underwent RSA for rotator cuff tear arthropathy from June 2016 to September 2020 by a single surgeon were retrospectively reviewed from a prospectively collected clinical database. Patients were separated into two groups: 1) patients who underwent RSA following prior ipsilateral shoulder arthroscopy (RSAPA) and 2) patients who underwent RSA without previous shoulder surgery (RSA). Patient-reported outcomes (PROs), including SST, ASES, UCLA score, SAS score, and active shoulder range of motion were measured preoperatively and at a minimum 2 years postoperative. Results A total of 103 patients (n=38 RSAPA and n=65 control RSA) were analyzed. The mean duration of follow-up for patients with prior ipsilateral shoulder arthroscopy was significantly shorter compared to the control patients (RSAPA=33 months and RSA=50 months, p < 0.0001). All PROs improved postoperatively (p < 0.001). Improvements in PROs for RSAPA were diminished relative to RSA control group patients, including SST (RSAPA=5.4 vs RSA=7.6, p = 0.005), ASES (RSAPA=40.8 vs RSA=54.7, p = 0.021), and UCLA (RSAPA=16 vs RSA=20.7, p = 0.009) scores. Improvements in forward flexion (RSAPA=69° vs RSA=95°, p = 0.0003) and abduction (RSAPA= 67° vs RSA=83°, p = 0.003) were decreased in the RSAPA group compared to the control group (RSA). One patient (1.5%) with prior shoulder arthroscopy required revision due to recurrent instability, whereas no patients in the control group required revision surgery (p=0.25). Conclusion Patients with rotator cuff tear arthropathy who underwent RSA following prior shoulder arthroscopy demonstrated significant improvements in function and patient-reported outcomes, but these outcomes are diminished compared to those patients with no history of surgery.

Kinematic differences in forehand serve-receiving techniques of the male tennis players at low and high-speed serves

The purpose of this study was to compare the joint, racket, and ball kinematics between the different levels of male tennis players in tennis serve-return at slow and high serve speeds. Thirty male tennis players were divided into an advanced group (n = 15) and an intermediate group (n = 15) based on skill level. The advanced group and intermediate group matched shake hand-grip players performed serve-receive test at the different serve speeds. Kinematic data were collected on the trunk, upper limbs, racket and ball to compare the differences between the advanced and intermediate groups at different serve speeds. At both serve speeds, the AG has faster racket speed and ball speed, and is closer to the baseline placement (p<0.05). It is characterized by a faster trunk turn, greater speed with the shoulder joint forward and outward and greater angle of wrist flexion and extension during the stroke (p<0.05), and greater speed with the forearm inward and internal rotation during the follow-through swing, at the same time, there is a difference in the angle of the racket to the ground between the advanced group and an intermediate group(p<0.05). Elbow internal rotation and abduction angular velocity in the backswing phase, Timing of peak racket resultant velocity and Wrist extension in the stroke phase, and shoulder and elbow joint activities in the follow-through phase were significantly correlated with the ball speed of the return. With faster serve speeds, higher quality serve-receive can be achieved by shortening the duration of the backswing lifting the upper arm and rotating the forearm inward quickly, accelerating the speed of movement of wrist joints at the impact phase, adjusting the speed of shoulder adduction and elbow internal rotation to complete the follow-through swing. These findings help to improve elite players’ serve-receive skills at faster serve speed.

Adherence to Physical Activity Guidelines in Manual Wheelchair Users With Spinal Cord Injury and the Association With Shoulder Pain.

The aim of the study is to investigate the association between adherence to spinal cord injury-specific physical activity guidelines in manual wheelchair users with spinal cord injury and shoulder pain prevalence. This is a cross-sectional analysis of the SwiSCI Community Survey 2022 data, assessing aerobic activity and muscle strength training adherence in manual wheelchair users with spinal cord injury and shoulder pain prevalence. Logistic regression analysis was used to identify the association between meeting the physical activity guidelines and shoulder pain. Low adherence to aerobic activity and strength training guidelines are observed, with 46% and 64% of the study sample not meeting the respective guidelines. The low adherence to physical activity guidelines contrasts with the general Swiss population from which around 75% is physically active for more than 2.5 hrs a week. Manual wheelchair users present a high prevalence of shoulder pain (40%) and nonadherence to aerobic guidelines in the study sample correlates with 1.55-1.97 higher odds of having shoulder pain. Aerobic activity adherence is associated with lower shoulder pain prevalence, emphasizing its potential for injury prevention. Overall, the presented findings necessitate further longitudinal studies and interventions for a comprehensive understanding and effective management of shoulder pain in manual wheelchair users with spinal cord injury.

Rehabilitation after reverse total shoulder arthroplasty: a survey of members of the American Shoulder and Elbow Surgeons

Surgeons disagree about whether patients should undertake home physical therapy (HPT) or formal physical therapy (FPT) after undergoing reverse total shoulder arthroplasty (RTSA). Recent studies suggest that HPT is as effective as FPT, but surgeons who perform RTSA may believe that FPT continues to have a role. Our primary purpose was to describe the opinions and self-reported practices of surgeons who perform RTSA regarding prescribing physical therapy (PT) after surgery. We also sought to identify factors associated with prescription of FPT. A survey was distributed electronically from May to September 2023 to the 1076 members of the American Shoulder and Elbow Surgeons who were practicing in the United States at that time. Of these surgeons, 237 (22%) responded to the survey. Anonymous responses were collected via Qualtrics, including demographic data and information about the RTSA implant systems used. Descriptive statistics were used to analyze surgeon characteristics, implant types, and rehabilitation practices. Multivariate logistic regression was used to identify surgeon, procedure, and implant characteristics associated with the likelihood of FPT prescription. Because some respondents reported using multiple RTSA implant types and some did not answer implant-specific questions, a total of 225 RTSA implant types were included. Forty-six percent of respondents reported that they recommended FPT for every patient; 64% said they typically prescribe FPT. A smaller proportion of respondents who had completed a hand and upper-extremity fellowship said that they prescribed FPT compared with those who had not completed such a fellowship. However, PT prescription was not associated with any other studied characteristics, such as number of years in practice or whether the surgeon tended to repair the subscapularis. On average, respondents estimated that 92% of their patients received either FPT or HPT. Respondents also reported varying timeframes for starting PT activities after surgery. For example, 50% of respondents reported recommending passive shoulder range of motion below the shoulder level within the first postoperative week, whereas 73% recommended waiting 2-6 weeks for active shoulder range of motion below shoulder level. Most surveyed surgeons prescribe FPT and/or HPT after primary RTSA, with a slight preference for FPT. Surgical factors did not influence rehabilitation preferences. Further randomized studies to investigate the impact of PT on clinical outcomes of RTSA are needed.

RELATIONSHIP BETWEEN SHOULDER FLEXIBILITY AND HANDSTAND ALIGNMENT IN DIFFERENT FEMALE ARTISTIC GYMNASTICS APPARATUS

A study was performed with the objective of analyzing the relationship between shoulder flexibility and handstand performance across three female artistic gymnastics apparatuses: floor exercise (FX), balance beam (BB), and uneven bars (UB). Twenty-one gymnasts participated and were divided into two groups: “G1”, consisting of twelve child gymnasts, and “G2”, consisting of nine adolescent gymnasts, aged 9 and 14 respectively. The study aimed to consider the sensitive phases for the development of flexibility. Using the Kinovea program, the shoulder angle (°H) in the handstand and the alignment of the joint segments (AJS) involved were analyzed. Participants underwent two different active shoulder flexibility tests (GFMT and FIG), and results were compared between the groups. Significant differences were found between groups in the GFMT test (p = 0.018), the FIG test (p = 0.026), and AJS in the BB handstand (p = 0.043). Significant relationships were also observed between the GFMT test and °H in UB (p = 0.021); and between the FIG test and °H in BB (p = 0.006), both withing the cild gymnast group. Overall, the adolescent group presented better scores, supporting the notion of greater body awareness and technical mastery of the handstand across the different female artistic gymnastics apparatuses.

Isolated Latissimus Dorsi Transfer versus Combined Latissimus Dorsi and Teres Major Tendon Transfer for Irreparable Anterosuperior Rotator Cuff Tears.

Irreparable anterosuperior rotator cuff tears (IASRCTs) present significant challenges, especially in young, active patients with limited joint-preserving options. Recently, latissimus dorsi (LD) transfer and combined latissimus dorsi and teres major (LDTM) transfer have gained attention as a potential surgical option. We aimed to compare the clinical and radiological outcomes of LD versus combined LDTM transfer in IASRCTs. In this retrospective comparative study, 53 patients with IASRCTs were analyzed after undergoing either LD transfer attached to lesser tuberosity (LT) (LD group, n = 23) or combined LDTM transfer attached to greater tuberosity (GT) (LDTM group, n = 30). Clinical evaluations included the visual analog scale score for pain, active shoulder range of motion (ROM), University of California Los Angeles Shoulder Score, American Shoulder and Elbow Surgeons score, activities of daily living that require active internal rotation (ADLIR) scores, and subscapularis (SSC)-specific examinations. Radiographic analyses involved assessing acromiohumeral distance (AHD), Hamada grade, the rate of anterior glenohumeral subluxation reduction, and integrity of the transferred tendon. Postoperatively, both groups demonstrated significant improvements in pain and clinical scores (p < 0.001). At the 2-year follow-up, the LDTM group showed superior internal rotation strength (p < 0.001), ADLIR score (p = 0.017), and SSC-specific physical examination results (belly-press, p = 0.027; bear-hug, p = 0.031; lift-off, p = 0.032). No significant changes in AHD or Hamada grade were observed in either group. At final follow-up, no significant differences were found between the 2 groups in terms of AHD (p = 0.539) and Hamada grade (p = 0.974). Although preoperative anterior glenohumeral subluxation was improved in both groups, the LDTM group showed a statistically significantly higher rate of restoration compared to the LD group (p = 0.015). While both LD and combined LDTM transfers for IASRCTs improved postoperative pain relief, clinical scores, and active ROM, the combined LDTM transfer attached to GT was superior to LD transfer attached to LT in terms of internal rotational strength, ADLIR score, and SSC-specific examinations. Neither group showed significant progress in cuff tear arthropathy or decreased AHD at 2-year follow-up; however, the combined LDTM transfer notably improved preoperative anterior glenohumeral subluxation.

Similar short-term outcomes of ultrasound guided posterior intra-articular and anterior extra-articular corticosteroid injection in the treatment of primary frozen shoulder. A randomized controlled, single-blind study.

Frozen shoulder, a condition characterized by the limitation of active and passive shoulder movements, is predominantly managed conservatively. Corticosteroid injection stands as a widely utilized and effective method for treatment. Nevertheless, the optimal approach for administering the injection remains a subject of controversy. We hypothesized that the injection of corticosteroid through anterior into the extra-articular area would yield superior results than the posterior intra-articular injection. This prospective, randomized, single-blind, and single-center clinical study aimed to compare the therapeutic effectiveness of ultrasound (USG)-guided injection techniques in patients with primary frozen shoulder. We continued the study with 54 patients who met the inclusion criteria. We evaluated patients pre-injection and at the first, third, and sixth weeks after injection. Two distinct approaches were employed: (1) Injection through the anterior extra-articular area around the coracohumeral ligament (CHL), and (2) injection through the posterior route into the glenohumeral joint. Evaluation parameters, including Visual Analog Scale (VAS) scores, active range of motion (ROM), American Shoulder and Elbow Surgeons (ASES) scores, and Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) scores, were assessed pre-injection and at the first, third, and sixth weeks post injection. No significant differences in the demographic and clinical characteristics, laboratory, or radiological findings were observed between the groups. It was observed that both groups exhibited similar and significant improvement in all measured parameters within their respective groups. Regarding pain scores, a notable decrease in VAS scores was observed in both groups (P = .000). There was no difference between the groups in terms of pre-injection VAS, QuickDASH, and ASES scores and active ROM measurements. The study concluded that there was no significant difference between ultrasound-guided injection of posterior intra-articular injection and anterior extra-articular injection concerning pain, ROM, and functional scores. Both techniques can be considered as viable options in the early stage of the disease. Level I, Therapeutic study.

Adolescent Shoulder Reconstruction Techniques in Brachial Plexus Birth Injury

Brachial plexus birth injury (BPBI) is common and while most recover, 8-36% of patients experience permanent impairment. Typically, adolescents with untreated BPBI lack active and passive external shoulder rotation (ER) and overhead shoulder function. Limited shoulder function is due to 1) nonoperative BPBI 2) untreated BPBI or 3) unrecognized glenohumeral joint dysplasia. We describe a technique for achieving reanimation in adolescents who did not receive timely/effective BPBI care, a postoperative rehabilitation protocol, and results from a series of eight patients who underwent shoulder reanimation. A comprehensive shoulder reanimation approach is performed. Anteriorly, the pectoralis minor, major, and anterior capsule necessitate release. In severe dysplasia, a coracoidectomy, posterior glenoid osteotomy, and/or subscapularis slide may be necessary. Acromial dysplasia is also common, frequently necessitating osteoplasty. The deltoid is usually nonfunctional, and we use a bipolar latissimus muscle transfer for reanimating abduction and forward flexion. To assist with ease of rehabilitation we will often transfer the tendon of the teres major. Levator scapulae transfer to the supraspinatus is often performed to assist with the initiation of abduction. For external rotation, the ipsilateral lower trapezius is used. Finally, ipsilateral rhomboid advancement and contralateral lower trapezius muscle transfer is performed for dynamic scapular stabilization. After surgery, all patients participated in our rigorous postoperative rehabilitation protocol. Eight patients (13.8±5.6 years, 35±24 weeks follow-up) were included. All patients participated in our rehabilitation protocol. Preoperatively, patients generally achieved 0° ER from neutral and in maximum abduction. Postoperatively, patients achieved an average of 71° (30-90°) ER from neutral and an average of 82° (65-90°) ER in maximum abduction. Preoperatively, patients generally had 0-20° of abduction, which they achieved through scapulothoracic motion. Postoperatively, patients could achieve an average of 115° (90-180°) of abduction. Preoperatively, patients had 0-20° of FF that was mediated through scapulothoracic motion. Postoperatively, patients' FF increased to an average of 91° (20-170°). This technique is intended to restore a congruent glenohumeral joint and reanimate structures allowing for abduction, FF, and ER. While we advocate for early treatment of BPBI, applying this technique to undertreated/untreated adolescent patients paired with our rehabilitation protocol results in significant functional improvement, allowing for an improved quality of life.

Effects of Sling-Suspension-Based Active Shoulder Joint Exercise on Shoulder Joint Subluxation, Pain, Muscle Strength, and Upper Limb Function in Patients with Subacute Stroke.

Background and Objectives: We investigated the effects of sling-suspension-based active shoulder joint exercise training on shoulder joint subluxation, pain, muscle strength, and upper extremity function in patients with subacute stroke. Materials and Methods: Twenty-eight patients with subacute stroke were randomly assigned to either the sling-suspension-based active shoulder joint exercise (SASE) group (n = 14) or the motorized upper extremity exercise (MUEE) group (n = 14). The SASE group actively performed shoulder joint flexion, extension, abduction, adduction, external and internal rotation, and horizontal abduction and adduction using a sling suspension system, whereas the MUEE group underwent an exercise program using a motorized upper extremity exercise machine. All participants underwent a 4-week intervention with 30 min of exercise once a day for 5 days a week. Additionally, both groups received general physical therapy and functional electrical stimulation for 30 min twice a day for 5 days a week. Shoulder joint subluxation was measured by radiographic examination before and after training, and pain was evaluated in the splenius, upper trapezius, and infraspinatus muscles using pressure parameters. In addition, a manual muscle tester was used to assess the muscle strength of the shoulder joint flexors, extensors, abductors, adductors, and external and internal rotators, and the Fugl-Mayer Assessment (FMA) and Manual Functional Test (MFT) were used to evaluate upper extremity function. Results: A significant group-time interaction was observed for pain, with F-values of F(1, 26) = 7.470, p < 0.011 for the splenius and F(1, 26) = 9.623, p < 0.005 for the upper trapezius. A significant time-group interaction was observed for the muscle strength of the shoulder, with F-values of F(1, 26) = 13.211, p < 0.001; F(1, 26) = 4.974, p = 0.035 and F(1, 26) = 9.674, p = 0.004 for flexors, abductors, and external rotators, respectively. A significant time-group interaction was observed in the FMA, with F-values of F(1, 26) = 13.243, p < 0.001. When comparing the interaction effects between time and group for MFT scores, a significant difference was observed, with F-values of F(1, 26) = 32.386, p < 0.001. Conclusions: This study confirmed that sling-suspension-based active shoulder joint exercises are effective in improving shoulder joint subluxation, pain, muscle strength, and upper extremity function in patients with subacute stroke.

Superior Capsular Reconstruction Using an Acellular Dermal Xenograft or Allograft Improves Shoulder Function but Is Associated with a High Graft Failure Rate.

Objectives: The purpose of the present study was to evaluate clinical and functional outcomes, graft integrity rate and progression of osteoarthritis after superior capsular reconstruction (SCR) at short-term follow-up. Methods: Consecutive patients that underwent SCR using an acellular dermal xeno- or allograft between May 2018 and June 2020 for the treatment of irreparable posterosuperior rotator cuff tears were included. Shoulder function (American Shoulder and Elbow Surgeons [ASES] score), pain (Visual Analog Scale [VAS] for pain) and active shoulder range of motion (ROM) were evaluated preoperatively and after a minimum of 24 months postoperatively. Isometric strength was measured at follow-up and compared to the contralateral side. Magnetic resonance imaging was performed to evaluate graft integrity and osteoarthritis progression (shoulder osteoarthritis severity [SOAS] score). Results: Twenty-two patients that underwent SCR using a xeno- (n = 9) or allograft (n = 13) were evaluated 33.1 ± 7.2 months postoperatively. Four patients in the xenograft group underwent revision surgery due to pain and range of motion limitations and were excluded from further analysis (revision rate: 18.2%). Shoulder function (ASES score: 41.6 ± 18.8 to 72.9 ± 18.6, p < 0.001), pain levels (VAS for pain: 5.8 ± 2.5 to 1.8 ± 2.0, p < 0.001) and active flexion (p < 0.001) as well as abduction ROM (p < 0.001) improved significantly from pre- to postoperatively. Active external rotation ROM did not improve significantly (p = 0.924). Isometric flexion (p < 0.001), abduction (p < 0.001) and external rotation strength (p = 0.015) were significantly lower in the operated shoulder compared to the non-operated shoulder. Ten shoulders demonstrated a graft tear at the glenoid (n = 8, 44.4%) or humerus (n = 2, 11.1%). Graft lysis was observed in seven shoulders (38.9%). The graft was intact in one shoulder (5.6%), which was an allograft. A significant progression of shoulder osteoarthritis was observed at follow-up (SOAS score: 42.4 ± 10.1 to 54.6 ± 8.4, p < 0.001). Conclusions: At short-term follow-up, SCR using an acellular dermal xeno- or allograft resulted in improved shoulder function and pain with limitations in active external rotation ROM and isometric strength. Graft failure rates were high and osteoarthritis progressed significantly. Level of Evidence: Retrospective cohort study, Level III.

Verification of acromion marker cluster and scapula spinal marker cluster methods for tracking shoulder kinematics: a comparative study with upright four-dimensional computed tomography

BackgroundThis study validated the accuracy of the acromion marker cluster (AMC) and scapula spinal marker cluster (SSMC) methods compared with upright four-dimensional computed tomography (4DCT) analysis.MethodsSixteen shoulders of eight healthy males underwent AMC and SSMC assessments. Active shoulder elevation was tracked using upright 4DCT and optical motion capture system. The scapulothoracic and glenohumeral rotation angles calculated from AMC and SSMC were compared with 4DCT. Additionally, the motion of these marker clusters on the skin with shoulder elevation was evaluated.ResultsThe average differences between AMC and 4DCT during 10°−140° of humerothoracic elevation were − 2.2° ± 7.5° in scapulothoracic upward rotation, 14.0° ± 7.4° in internal rotation, 6.5° ± 7.5° in posterior tilting, 3.7° ± 8.1° in glenohumeral elevation, − 8.3° ± 10.7° in external rotation, and − 8.6° ± 8.9° in anterior plane of elevation. The difference between AMC and 4DCT was significant at 120° of humerothoracic elevation in scapulothoracic upward rotation, 50° in internal rotation, 90° in posterior tilting, 120° in glenohumeral elevation, 100° in external rotation, and 100° in anterior plane of elevation. However, the average differences between SSMC and 4DCT were − 7.5 ± 7.7° in scapulothoracic upward rotation, 2.0° ± 7.0° in internal rotation, 2.3° ± 7.2° in posterior tilting, 8.8° ± 7.9° in glenohumeral elevation, 2.0° ± 9.1° in external rotation, and 1.9° ± 10.1° in anterior plane of elevation. The difference between SSMC and 4DCT was significant at 50° of humerothoracic elevation in scapulothoracic upward rotation and 60° in glenohumeral elevation, with no significant differences observed in other rotations. Skin motion was significantly smaller in AMC (28.7 ± 4.0 mm) than SSMC (38.6 ± 5.8 mm). Although there was smaller skin motion in AMC, SSMC exhibited smaller differences in scapulothoracic internal rotation, posterior tilting, glenohumeral external rotation, and anterior plane of elevation compared to 4DCT.ConclusionThis study demonstrates that AMC is more accurate for assessing scapulothoracic upward rotation and glenohumeral elevation, while SSMC is preferable for evaluating scapulothoracic internal rotation, posterior tilting, glenohumeral external rotation, and anterior plane of elevation, with smaller differences compared to 4DCT.

Comparing and characterizing scapular muscle activation ratios in males and females during execution of common functional movements.

The shoulder complex relies on scapular movement controlled by periscapular muscles for optimal arm function. However, minimal research has explored scapular muscle activation ratios during functional tasks, nor how they might be influenced by biological sex. This investigation aims to characterize how sex impacts scapular muscle activation ratios during functional tasks. Twenty participants (ten females, ten males) were assessed with surface electromyography (EMG) and motion tracking during seven functional tasks. Activation ratios were calculated from normalized EMG for the three trapezius muscles and serratus anterior. Scapular angles were calculated using a YXZ Euler sequence. Two-way mixed methods ANOVAs (p<.05) were used to assess the effects of sex and humeral elevation level on ratios and angles. Sex-based differences were present in the Tie Apron task, with males exhibiting higher upper trapezius/lower trapezius and upper trapezius/middle trapezius ratios than females. Males also demonstrated decreased internal rotation in this task. Other tasks showcased significant sex-based differences in scapular upward rotation but not in activation ratios. Humeral elevation generally demonstrated an inverse relationship with scapular muscle activation ratios. This study highlights sex-based differences in scapular muscle activation ratios during specific functional tasks, emphasizing the need to consider sex in analyses of shoulder movements. Normative activation ratios for functional tasks were provided, offering a foundation for future comparisons with non-normative groups. Further research is warranted to confirm and explore additional influencing factors, advancing our understanding of shoulder activation and movement in diverse populations.

Effects of laptop screen height on neck and shoulder muscle fatigue and spine loading for office workers.

Due to the unfavourable neck-shoulder muscle loads caused by poor posture, the people who use the laptop for a long time may face the risk of neck and shoulder injuries. The purpose of this study investigates the impact of the screen height on the muscle activation of head flexion, neck and shoulder, and the cervical spine torque to provide the favorite screen height for laptop user. Twelve healthy young participants completed a15-minute task of the reading at the four different screen heights. sEMG signals of the splenius capitis (SC) and upper trapezius (UT) were measured and calculated the root mean square (RMS) and mean power frequency (MPF) to determine muscle fatigue. The different height of laptop users was simulated and the forces on the spine of users at different screen heights were analyzed by Jack. Adjusting the height of the laptop screen can effectively reduce head flexion and muscle activity of SC and UT, and has a positive effect on reducing fatigue of SC, but has no significant effect on UT. Adjusting the height of the laptop screen can delay the occurrence of SC muscle fatigue to a certain extent. The joint analysis of sEMG spectrum and amplitude reports that the screen heights of D15 and D45 have the highest and the lowest frequency of fatigue, respectively. At the same time, the moment of spineT1/T2 and spineL4/L5 decrease with the increase of screen height.

Pool-Based Surfboard Elicits Activation of Posterior Shoulder Muscles During a Surfing Stroke.

Pexa, BS, Johnston, CD, Elder, EE, Ford, KR, Patterson, MQ, and Myers, JB. Pool-based surfboard elicits activation of posterior shoulder muscles during a surfing stroke. J Strength Cond Res 38(7): 1300-1304, 2024-Surfboard paddling may activate posterior shoulder muscles, which are critical to baseball pitchers' injury risk and performance. The purpose of this study was to measure posterior shoulder muscle activation during different phases of the surf stroke (propulsion vs. recovery) on a pool-based surfboard. Twenty healthy active adult subjects completed a familiarization and testing session with the pool-based surfboard. During the testing session, electromyography (EMG) sensors were placed on 6 posterior shoulder muscles: latissimus dorsi, infraspinatus, posterior deltoid, upper trapezius, middle trapezius, and lower trapezius. Subjects completed 4 laps in a pool at 3 separate resistances (low, moderate, and heavy) in a randomized order. The peak EMG signal during each phase (propulsion and recovery) was recorded. A 2-way within subject ANOVA (resistance-by-phase) with post hoc Bonferroni's corrections was used to identify differences in EMG activation. There was a significant main effect of phase for the latissimus dorsi (F = 91.3, p < 0.001), upper trapezius (F = 36.5, p < 0.001), middle trapezius (F = 33.8, p < 0.001), and lower trapezius (F = 21.6, p < 0.001). The latissimus dorsi demonstrated higher activation during the propulsion phase (p < 0.001), and all trapezius muscles demonstrated higher activation during the recovery phase (p < 0.001). There was a significant main effect of resistance for the posterior deltoid (F = 3.4, p = 0.043), with higher muscle activation in the low resistance trials compared with the heavy resistance trials (p = 0.036). Recreationally active individuals demonstrate activation of the posterior shoulder when using a pool-based surfboard. This pool-based surfboard may be beneficial to activate the posterior musculature and may be more accessible than standard surfing to baseball athletes.

Effect of different resistance increments during warm-up on the snatch performance of male weightlifters

This study investigated the effect of different resistance increments during warm-up on snatch performance of male weightlifters. Nine male college weightlifters were recruited. The 3 warm-up protocols were performed every 7 days with a randomized order: 1. Power snatch exercise with 10 % resistance increment (50 %, 60 %, 70 %, and 80 % of one-repetition maximum); 2. Power snatch exercise with 15 % resistance increment (50 %, 65 %, and 80 % of one-repetition maximum); 3. Self-selected resistance increment. Participants were tested based on 85 % maximum weight snatch after warm-up. Snatch performance was measured using peak vertical ground reaction force. Postural stability was measured using center-of-pressure displacement. Activation of seven shoulder, back, and leg muscles was measured using electromyography on the dominant side. In snatch performance, the 10 % increment protocol had a significantly higher peak vertical ground reaction force during the second-pull phase than the 15 % increment (d = 0.92, p < 0.05) and self-selected (d = 1.32, p < 0.05) protocols. In postural stability, no significant differences in center-of-pressure displacement among the three protocols were observed. For muscle activation, the 10 % increment protocol resulted in significantly higher activation of shoulder (d = 1.2–2.2, p < 0.05) during the second-pull phase than the other two protocols and higher activation of hip muscles (d = 1.73, p < 0.05) than self-selected protocol. To conclude, a warm-up protocol combining slow progression is preferable in improving power output during snatch in male weightlifters, probably through facilitating the activation of proximal limb muscles. It can enhance training quality while potentially reducing the risk of sports injuries.

Paper 29: Incidental Teres Minor Atrophy in Patients Undergoing Arthroscopic Rotator Cuff Repair of the Supraspinatus Occurs Frequently and is Associated with Worse Postoperative Outcomes Without Higher Failure Rates

Objectives: Fatty infiltration and rotator cuff atrophy has been associated with poor clinical outcomes during rotator cuff repairs. Compared to supraspinatus and infraspinatus atrophy there has been minimal research on the effect of teres minor atrophy on surgical outcomes and failure rates in rotator cuff repairs. The purpose of this study was to assess the incidence and outcomes of arthroscopic rotator cuff repairs (ARCR) for partial and full thickness supraspinatus tears in patients with incidentally identified teres minor fatty infiltration. Methods: A consecutive series of 272 shoulders from 256 patients who underwent arthroscopic, double row transosseous equivalent repairs by 3 fellowship trained surgeons with minimum 1 years follow up for partial and full thickness tears of the supraspinatus tendon was reviewed. Revision repairs and concomitant subscapularis repairs were excluded. Preoperative MRI was reviewed to classify teres minor fatty infiltration using the modified Goutallier classification. Preoperative and postoperative range of motion, strength, visual analog scale (VAS), subjective shoulder value (SSV), Patient-Reported Outcomes Measurement Information System (PROMIS) mental/physical health, American Shoulder and Elbow Surgeons Shoulder Score (ASES), and Brophy shoulder activity scores were collected. Failure defined as a symptomatic retear identified on postoperative MRI or need for revision surgery was also collected. Paired t-tests, Chi-squared, and Fisher’s exact tests were utilized for continuous and binary variables, respectively. Statistical significance was at p &lt; 0.05. Results: A total of 106 patients met the inclusion criteria with 47 partial thickness tears and 59 full thickness tears. The average age of 67 and average follow-up of 30 months (range 10-92) were included. Tear size (16.37 vs 13.62, p = 0.30), and Goutallier classification of supraspinatus (0.51 vs 0.62, p =0.41), and infraspinatus (0.42 vs 0.47, p = 0.81) did not differ between the two groups. Incidental teres minor fat infiltration was present in 53% of cases with an overall frequency in Goutallier stage as follows: 47% - Grade 0, 38% - Grade 1, 14% - Grade 2, 1% - Grade 3, and 0% - Grade 4. For partial tears, postoperative PROMIS mental and physical scores were significantly better in those without teres minor fatty infiltration versus in those without (16.7 vs 14.3, p=0.01; 15.5 vs 13.5, p=0.02), while ROM, strength, and PROs were not statistically significant. For full tears, those without fat infiltration had statistically significantly better PROs on PROMIS physical (16.25 vs 14.07, p=0.01), ASES (83 vs 63, p=0.02), Brophy (8.3 vs 5.2, p=0.02), and SSV scores (94 vs 83, p=0.046). No other differences in ROM, strength, and other PROs were identified. No differences were identified for retear and revision rates among patients regardless of fatty infiltration (partial: retear, 7.7% vs 9.5%, p = 0.59; revision, 7.7% vs 9.5%, p = 0.59; revision, 12.5% vs 5.7%, p = 0.18). Conclusions: Our study demonstrates that incidentally noted teres minor fatty infiltration occurs in over 50% of patients undergoing arthroscopic rotator cuff repair for full thickness supraspinatus tears and is associated with worse postoperative outcome scores without higher failure rates. Compared to full thickness tears, teres minor atrophy in partial thickness tears showed a lesser effect on outcome scores with only significantly worse post operative PROMIS mental and physical scores. Identification of these patients preoperatively with strategies to optimize may be necessary to improve outcomes.

Nonoperative Versus Operative Treatment of Z-Type Comminuted Clavicle Fractures in Adolescents: A Prospective Substratified Cohort Analysis.

To compare the clinical, radiographic, and patient-reported outcomes of nonoperative and operative treatment of adolescents with comminuted "Z-type" midshaft clavicle fractures. Prospective observational cohort. Eight tertiary care pediatric centers. Patients aged 10-18 years who were treated either operatively or nonoperatively for a diaphyseal clavicle fracture between 2013 and 2017 were screened/enrolled at the time of injury. The current subcohort analysis was derived from a larger adolescent clavicle study population of 907 patients. Complications and validated patient-reported outcome measures (PROs):(ASES, QuickDASH, Marx Shoulder Activity Score, EQ-5D, EQ-VAS, and patient satisfaction score) were compared between operative and nonoperative cohorts. Eighty-one patients (69 male [85.2%], 12 female; average age 15 years [11.1-18.7]; 78 with sports participation [96.2%]) were followed through bony healing and return to sports, while 59 patients (73%) completed 2-year follow-up with PROs, 26 of whom were treated nonoperatively and 33 treated operatively. All demographic and fracture characteristics were similar (P > 0.05) between the 2-year follow-up cohorts except for fracture shortening, which was greater in the operative cohort (23 vs. 29 mm, P = 0.01). After controlling for this potential confounder through both regression and propensity matched subgroup analysis, nonoperative versus operative cohorts showed no difference in rates of nonunion (0%), delayed union (0% vs. 2.3%, P = 1.0), symptomatic malunion (2.7% vs. 0%, P = 0.4), refracture (2.7% vs. 2.2%, P = 1.0), unexpected subsequent surgery (5.4% vs. 11.4%, P = 0.45), or clinically significant complications (5.4% vs. 16%, P = 0.17). There were no differences in any PROs between cohorts, both before and after controlling for the difference in fracture shortening (all P-values >0.05). In this prospective comparison of complications and 2-year PROs in adolescents with comminuted Z-type clavicle fractures, nonoperative and operative treatment yielded similar outcomes. Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Human Activity Recording Based on Skin-Strain-Actuated Microfluidic Pumping in Asymmetrically Designed Micro-Channels.

The capability to record data in passive, image-based wearable sensors can simplify data readouts and eliminate the requirement for the integration of electronic components on the skin. Here, we developed a skin-strain-actuated microfluidic pump (SAMP) that utilizes asymmetric aspect ratio channels for the recording of human activity in the fluidic domain. An analytical model describing the SAMP's operation mechanism as a wearable microfluidic device was established. Fabrication of the SAMP was achieved using soft lithography from polydimethylsiloxane (PDMS). Benchtop experimental results and theoretical predictions were shown to be in good agreement. The SAMP was mounted on human skin and experiments conducted on volunteer subjects demonstrated the SAMP's capability to record human activity for hundreds of cycles in the fluidic domain through the observation of a stable liquid meniscus. Proof-of-concept experiments further revealed that the SAMP could quantify a single wrist activity repetition or distinguish between three different shoulder activities.

Subacromial balloon spacer massive rotator cuff tear treatment systematic review and meta-analysis: Patient selection and physical therapy may be keys to outcome success.

Subacromial balloon spacer implantation (SBSI) efficacy for massive rotator cuff tear treatment was evaluated based on perceived shoulder function, active shoulder mobility, pain, complications and research study methodological quality. The purpose was to better discern the efficacy of this device from both surgical and rehabilitative perspectives to improve patient outcomes. PubMed, EMBASE and Cochrane Library databases were searched (1 January 2010 to 1 June 2024) using 'balloon spacer', 'subacromial spacer', 'subacromial balloon spacer', 'shoulder spacer' and 'inspace' terms. Pre-surgery (baseline), 12-month (12-m) and 24-month (24-m) post-SBSI mean changes were compared using one-way ANOVA and Scheffe post hoc tests, and comparative study effect sizes were calculated (p ≤ 0.05). This review consists of 27 studies with 894 patients (67.8 ± 5 years of age) and 29.4 ± 17-month follow-up. Modified Coleman Methodology Scores (MCMS) revealed fair overall quality (mean = 61.4 ± 11). Constant-Murley scores improved from 34.8 ± 6 (baseline), to 64.2 ± 9 (12-m) and 67.9 ± 8 (24-m) (12-m, 24-m > baseline, p < 0.001). ASES scores improved from 35.1 ± 14 (baseline), to 83.3 ± 7 (12-m) and 81.8 ± 5 (24-m)(12-m, 24-m > baseline, p < 0.001). VAS pain scores improved from 6.6 ± 1 (baseline), to 2.6 ± 1 (12-m) and 2.0 ± 1 (24-m) (12-m, 24-m < baseline, p < 0.001). Flexion increased from 108.5 ± 25° (baseline), to 128.5 ± 30° (12-m) and 151.2 ± 14° (24-m) (24-m > 12-m, baseline, p = 0.01). Abduction increased from 97.7 ± 24° (baseline) to 116.3 ± 23° (12-m) and 142.3 ± 15° (24-m) (24-m > 12-m, baseline, p = 0.02). External rotation (ER) in adduction changed from 33.1 ± 7° (baseline) to 32.5 ± 4° (12-m) and 53.9 ± 9° (24-m)(24-m > 12-m, baseline, p = 0.01). ER at 90° abduction increased from 56.3 ± 3° (baseline) to 83.5 ± 5° (12-m) and 77.1 ± 4° (24-m) (24-m, 12-m > baseline, p = 0.01). Comparison studies, however, displayed insignificant results with small effect sizes. Despite overall fair MCMS scores, at 24-m post-SBSI, shoulder function improved and pain decreased. More rigorous comparative studies, however, revealed insignificant findings. Patients with the potential to re-establish the essential glenohumeral joint force couple that depresses the humeral head on the glenoid fossa and who comply with physical therapy may be more likely to achieve success following SBSI. Level IV.