Muscle Activity Before and After Subacromial Injection

2021 ◽  
pp. 1-7
Author(s):  
Lucas Ettinger ◽  
Matthew Shaprio ◽  
Andrew Karduna
Keyword(s):  
Rotator Cuff ◽  
Muscle Activation ◽  
Rotator Cuff Tears ◽  
Subacromial Impingement ◽  
Upper Trapezius ◽  
Subacromial Injection ◽  
Shoulder Muscle ◽  
Shoulder Muscles ◽  
Before And After ◽  
Arm Elevation

Context: Shoulder muscle activation in patients with subacromial impingement is highly cited and variable in the literature. Differences between studies could be due to artifacts introduced by normalization practices in the presence of pain. Ultimately, this lack of knowledge pertaining to pathogenesis limits the clinical treatment and restoration of muscular function. Design: A total of 21 patients with stage 2 subacromial impingement and 21 matched controls were recruited for EMG testing of their affected shoulder during an arm elevation task. The patients were tested before and after receiving an injection to their subacromial bursa. Methods: The EMG from 7 shoulder muscles were measured before and after treatment during humeral motion in the scapular plane. Results: Our findings indicate an increase in anterior deltoid, middle deltoid, and upper trapezius activity following the injection; further, this trend extended to the controls. The control subjects had a greater activation of the latissimus dorsi at peak arm elevation when compared with the patient group postinjection. Conclusions: Our results indicate that a reduction in subacromial pain is associated with changes in shoulder muscle recruitment, primarily of the deltoid. This change in deltoid activity may lend evidence to rotator cuff function in patients without rotator cuff tears.

Normalization to Maximal Voluntary Contraction is Influenced by Subacromial Pain

2016 ◽  
Vol 32 (5) ◽  
pp. 433-440 ◽  
Author(s):  
Lucas Ettinger ◽  
Jason Weiss ◽  
Matthew Shapiro ◽  
Andrew Karduna
Keyword(s):  
Trapezius Muscle ◽  
Pain Scale ◽  
Voluntary Contraction ◽  
Subacromial Impingement Syndrome ◽  
Serratus Anterior ◽  
Upper Trapezius ◽  
Subacromial Injection ◽  
Shoulder Muscle ◽  
Before And After ◽  
Lower Trapezius

In this study, we aimed to determine if electromyography (EMG) normalization to maximal voluntary isometric contractions (MVIC) was influenced by subacromial pain in patients with subacromial impingement syndrome. Patients performed MVICs in unique testing positions for each shoulder muscle tested before and after subacromial injection of local anesthetic. In addition to collection of MVIC data, EMG data during an arm elevation task were recorded before and after injection. From a visual analog pain scale, patients had a 64% decrease in pain following the injection. Significant increases in MVICs were noted in 4 of the 7 shoulder muscles tested: anterior, middle and posterior deltoid, and lower trapezius. No significant differences were noticed for the upper trapezius, latissimus dorsi, or serratus anterior. MVIC condition (pre and post injection) had a significant influence on EMG normalization for the anterior deltoid and lower trapezius muscle. Results indicate that subacromial pain can influence shoulder muscle activity, especially for the deltoid muscles and lower trapezius. In addition, normalization to MVIC in the presence of pain can have unpredictable results. Caution should be taken when normalizing EMG data to MVIC in the presence of pain.

scholarly journals Delayed Anticipatory Muscle Activation in Rotator Cuff Tendinopathy

2021 ◽  
Vol 9 (7) ◽  
pp. 232596712110193
Author(s):  
Samuel Baek ◽  
Se-Young Ki ◽  
Seok Won Chung ◽  
Seoung-Joon Lee ◽  
Young Chang Cho ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Muscle Activation ◽  
Onset Time ◽  
Unaffected Side ◽  
Number Count ◽  
Upper Trapezius ◽  
Affected Side ◽  
Shoulder Muscles ◽  
The Central Nervous System ◽  
Anterior Deltoid

Background: Previous research investigating rotator cuff (RC) tendinopathy has usually focused on pathoanatomy. The pathologic response to anticipatory postural adjustments (APAs) has not yet been investigated. Purpose/Hypothesis: To explore changes in APAs as detected by pre-emptive activation of shoulder muscles during ball catching. It was hypothesized that anticipatory muscle activation (AMA) would be present in the unaffected shoulder but delayed or absent in the affected shoulder in patients with RC tendinopathy. Study Design: Controlled laboratory study. Methods: This study included 21 RC tendinopathy patients with a mean age of 49.5 years. Patients were required to grab a ball embedded with an electromyography sensor when it dropped on their hand, and surface electromyography signals were recorded from the infraspinatus, upper trapezius, anterior deltoid, and biceps. The trials utilized 2 balls, weighing 200 g and 500 g. Each ball was used in 2 trials, 1 involving a number count preceding the ball drop (predictable) and the other involving a sudden drop (unpredictable). The onsets of AMA between the affected and unaffected limbs were compared. Results: Regardless of the experimental condition, significantly delayed AMA onsets were identified in all investigated muscles of the affected side compared with those of the unaffected side, except for the biceps muscle in the 500-g predictable trial. For the infraspinatus, the mean onset time in the 200-g predictable trial was –141.0 ± 60.2 ms on the affected side and –211.9 ± 67.1 ms on the unaffected side ( P < .001); in the 200-g unpredictable trial this value was –139.5 ± 54.9 ms on the affected side and –199.5 ± 56.2 ms on the unaffected side ( P < .001). Conclusion: Delayed AMA was observed in the affected shoulder compared with the unaffected shoulder in patients with RC tendinopathy, not only in the RC muscle but also in the periscapular and upper arm muscles. This may indicate that central hypoexcitability is partly responsible. Clinical Relevance: The basis for RC tendinopathy treatment should not be limited to the tendon pathoanatomy. Delayed AMA around the shoulder joint could provide insight into potential mechanisms related to the central nervous system.

scholarly journals Rotátorköpeny-szakadás után kialakult zsíros degeneráció változása az ín rekonstrukcióját követően, 65 éves kor után

2019 ◽  
Vol 160 (14) ◽  
pp. 533-539
Author(s):  
Imre Sallai ◽  
Márton Weidl ◽  
Attila Szatmári ◽  
Imre Antal ◽  
Gábor Skaliczki
Keyword(s):  
Rotator Cuff ◽  
Muscle Atrophy ◽  
Rotator Cuff Repair ◽  
Constant Score ◽  
Fatty Degeneration ◽  
Shoulder Function ◽  
Rotator Cuff Tears ◽  
Before And After ◽  
Cuff Repair

Abstract: Introduction: In the case of rotator cuff tears, the severity of the muscle atrophy and fatty degeneration has an effect on the success of the repair and on the functional outcome after surgery. Aim: The ability of regeneration reduces with ageing; therefore, the study examined the atrophy and the fatty degeneration after rotator cuff repair in patients over 65. Method: Eleven patients over 65 years of age were involved whose surgery was performed at the Department of Orthopaedics of Semmelweis University between 2012 and 2015. Their average age was 71.9 years and the average follow-up period was 39.9 months. Tear sizes were C1 in 3 cases, C2 in 3 cases, C3 in 4 cases, and C4 in 1 case. Each patient had magnetic resonance examination before and after the repair; the muscle atrophy and fatty degeneration were evaluated together with the type of the tear. Visual analogue scale and Constant score were used for the assessment of the pain and the shoulder function. Results: The average Constant score was 75 points. The occupancy ratio – referring to the severity of the atrophy – did not show significant improvement. The change in fatty degeneration and the atrophy were examined in different groups according to the size of the tears. In each group, the results showed progression. Conclusions: After rotator cuff repair in patients over 65, fatty degeneration and muscle atrophy also show progression. No significant relationship was found between the size of the tear and fatty degeneration or between the size of the tear and muscle atrophy. Orv Hetil. 2019; 160(14): 533–539.

Differential patterns of muscle activation in patients with symptomatic and asymptomatic rotator cuff tears

2005 ◽  
Vol 14 (2) ◽  
pp. 165-171 ◽  
Author(s):  
Bryan T. Kelly ◽  
Riley J. Williams ◽  
Frank A. Cordasco ◽  
Sherry I. Backus ◽  
James C. Otis ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Muscle Activation ◽  
Rotator Cuff Tears

scholarly journals Correlation between Rotator Cuff Tears and Repeated Subacromial Steroid Injections: A Case-Controlled Study

2009 ◽  
Vol 91 (5) ◽  
pp. 414-416 ◽  
Author(s):  
M Bhatia ◽  
B Singh ◽  
N Nicolaou ◽  
KJ Ravikumar
Keyword(s):  
Rotator Cuff ◽  
Causative Factor ◽  
Rotator Cuff Tears ◽  
Controlled Study ◽  
Distribution Analysis ◽  
Subacromial Impingement ◽  
Subacromial Space ◽  
Retrospective Case ◽  
Significant Difference ◽  
Magnetic Resonance Imaging Mri

INTRODUCTION Concern exists regarding potential damage to the rotator cuff from repeated corticosteroid injections into the subacromial space. PATIENTS AND METHODS In this retrospective, case-controlled study, 230 consecutive patients presenting to three orthopaedic units with subacromial impingement and investigated as an end-point with magnetic resonance imaging (MRI) of the shoulder were divided into groups having received less than three or three or more subacromial injections of corticosteroids. RESULTS With no significant difference in age and sex distribution, analysis by MRI showed no significant difference between the two groups in the incidence of rotator cuff tear (P < 1.0). CONCLUSIONS This suggests that corticosteroid use in patients with subacromial impingement should not be considered a causative factor in rotator cuff tears.

scholarly journals Outcomes of superior capsule reconstruction for massive rotator cuff tears and risk factors for postoperative retear

2019 ◽  
Vol 140 (10) ◽  
pp. 1319-1325
Author(s):  
Satoru Ohta ◽  
Osamu Komai ◽  
Yuuki Onochi
Keyword(s):  
Risk Factors ◽  
Rotator Cuff ◽  
Multiple Regression ◽  
Postoperative Outcomes ◽  
Rotator Cuff Tears ◽  
X Rays ◽  
Massive Rotator Cuff Tears ◽  
Superior Capsule Reconstruction ◽  
Stage 4 ◽  
Before And After

Abstract Introduction Superior capsule reconstruction (SCR) has been used for the tendon grafting of massive rotator cuff tears when primary repair is difficult. We examined the postoperative outcomes of SCR for massive rotator cuff tears and the risk factors for postoperative retear. Materials and methods Through this retrospective comparative study, we evaluated 35 patients with an average age of 75.3 (57–90) years who underwent SCR using the technique developed by Mihata et al. Clinical outcomes were evaluated 1 year postoperatively using the Japan Orthopedic Association (JOA) score, University of California Los Angeles (UCLA) shoulder score, elevation angle and the Sugaya classification, which uses a 5-point scale evaluation on magnetic resonance imaging in which types 4 and 5 are considered retears. We also investigated the progression of fatty degeneration before and after surgery and the rupture site of the graft. Acromio-humeral distance (AHD), before and after surgery was measured through X-rays. Rotator cuff tear-related shoulder arthritis was evaluated on plain X-rays using the Hamada stage. Risks of retear were identified using multiple regression analyses for sex, age, Hamada stage and JOA score. Results The JOA score improved from 62.3 ± 9.49 (SD) preoperatively to 84.6 ± 5.66 (SD) postoperatively (P < 0.001). The UCLA score improved from 15.3 ± 3.77 (SD) preoperatively to 30.1 ± 3.11 (SD) postoperatively (P < 0.001). AHD increased from 4.03 mm preoperatively to 6.23 mm postoperatively (P < 0.001). Postoperative retear was observed in seven of the 35 patients. Moreover, retear was observed in five of nine patients with a Hamada stage ≥ 4. Multiple regression analysis revealed that age ≥ 80 years, male sex and Hamada stage ≥ 4 were risk factors for retear. Conclusions While the postoperative outcomes of SCR are favorable, age, sex and degree of arthropathic change should be considered for surgical indications of SCR.

Surface Electromyography Reveals Middle Deltoid as The Functionally Dominant Shoulder Muscle After Reverse Total Shoulder Arthroplasty

2021 ◽  
Author(s):  
Emily Lau ◽  
Alexander Pietroski ◽  
Sreten Franovic ◽  
Yang Zhou ◽  
Noah Kuhlmann ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Shoulder Arthroplasty ◽  
Muscle Activation ◽  
Total Shoulder Arthroplasty ◽  
Deltoid Muscle ◽  
Reverse Total Shoulder Arthroplasty ◽  
Shoulder Abduction ◽  
Shoulder Muscle ◽  
Significant Difference ◽  
Reverse Total Shoulder

Abstract Background: Reverse total shoulder arthroplasty (RSA) increases deltoid muscle fiber recruitment and tension to compensate for deficient rotator cuff activity; however, it is unclear whether the anterior or middle deltoid becomes dominant and how the muscle activation profile changes postoperatively. Using minimally invasive electromyography, this study evaluated the activity of the deltoid and surrounding muscles during shoulder motion to assess muscle activation changes post-RSA. Methods: In this observational study, we assessed change in preoperative to postoperative shoulder muscle activation in 10 patients over 6 months. Muscle activation was measured using 8 surface electrodes. Activation of the anterior, middle and posterior deltoid and surrounding muscles were recorded during shoulder abduction, flexion, external and internal rotation were quantified. One-way analysis of variance was used to identify significant differences in activation and time or speed. Least significant difference post hoc test was used to determine specific differences in muscle activation at subsequent time points. Results: RSA shoulders at 6 months postoperative showed a significant increase in activity of the middle deltoid predominantly. Middle deltoid activation increased during abduction (P < 0.001), flexion (P = 0.008), external (P < 0.001) and internal (P < 0.001) rotation. Conclusions: Our study demonstrates the middle deltoid predominates in rotator cuff function in RSA as defined by quantitative activation, significant involvement in all shoulder motions, and increased activation at subsequent times. These findings may help guide future RSA designs to optimize deltoid wrapping allowing for maximal strength and efficiency.

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