scholarly journals An in-vitro biomechanical assessment of humeral head migration following irreparable rotator cuff tear and subacromial balloon reconstruction

2019 ◽  
Vol 12 (4) ◽  
pp. 265-271
Author(s):  
Jacob M Reeves ◽  
Supriya Singh ◽  
G Daniel G Langohr ◽  
George S Athwal ◽  
James A Johnson
Keyword(s):  
Rotator Cuff ◽  
Humeral Head ◽  
Muscle Activation ◽  
Rotator Cuff Tears ◽  
Biomechanical Assessment ◽  
Intact State ◽  
Optical Markers ◽  
Irreparable Rotator Cuff Tear ◽  
Head Translation

Background A resorbable subacromial balloon has been developed to address humeral head migration following posterosuperior rotator cuff tears. The purpose of this experimental assessment was to quantify the effect of balloon augmentation on humeral head position. Methods Eight cadaveric shoulders were subjected to 0°, 30°, 60° and 90° of abduction via a shoulder simulator. The deltoid was activated at 40N, then 80N. The subscapularis and infraspinatus with teres minor were then applied independently and together to create four muscle activation states for each deltoid load. The shoulder was tested intact, torn, then with the balloon. The centre of the humeral head was tracked using active optical markers. Results When the rotator cuff was torn, the humeral head translated superior by 1.4 ± 1 mm overall (P = 0.009). Following balloon augment, the humeral head translated inferiorly by 2 ± 2 mm relative to the intact state (P = 0.042), and significantly more anterior than the intact (3 ± 2 mm; P = 0.005) state. Rotator cuff variation was only significantly different when the balloon was used, with the subscapularis translating the humeral head posteriorly (P = 0.006). Discussion The subacromial balloon inferiorized the humeral head compared to the torn state. Unexpected anterior humeral head translation was attributed to the posterosuperior balloon placement relative to the humeral head.

Superior Capsule Reconstruction With a 3 mm–Thick Dermal Allograft Partially Restores Glenohumeral Stability in Massive Posterosuperior Rotator Cuff Deficiency: A Dynamic Robotic Shoulder Model

2021 ◽  
pp. 036354652110133
Author(s):  
Lucca Lacheta ◽  
Alex Brady ◽  
Samuel I. Rosenberg ◽  
Travis J. Dekker ◽  
Ritesh Kashyap ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Rotator Cuff Tear ◽  
Humeral Head ◽  
Supraspinatus Tendon ◽  
Rotator Cuff Tears ◽  
Neutral Position ◽  
Tendon Tear ◽  
Cuff Tear ◽  
Superior Capsule Reconstruction ◽  
Head Translation

Background: Superior capsule reconstruction (SCR) has been shown to improve shoulder function and reduce pain in patients with isolated irreparable supraspinatus tendon tears. However, the effects of SCR on biomechanics in a shoulder with an extensive posterosuperior rotator cuff tear pattern remain unknown. Purpose/Hypothesis: The purpose was to (1) establish a dynamic robotic shoulder model, (2) assess the influence of rotator cuff tear patterns, and (3) assess the effects of SCR on superior humeral head translation after a posterosuperior rotator cuff tear. It was hypothesized that a posterosuperior rotator cuff tear would increase superior humeral head translation when compared with the intact and supraspinatus tendon–deficient state and that SCR would reduce superior humeral head translation in shoulders with massive rotator cuff tears involving the supraspinatus and infraspinatus tendons. Study Design: Controlled laboratory study. Methods: Twelve fresh-frozen cadaveric shoulders were tested using a robotic arm. Kinematic testing was performed in 4 conditions: (1) intact, (2) simulated irreparable supraspinatus tendon tear, (3) simulated irreparable supra- and infraspinatus tendon tear, and (4) SCR using a 3 mm–thick dermal allograft (DA). Kinematic testing consisted of static 40-N superior force tests at 0°, 30°, 60°, and 90° of abduction and dynamic flexion, abduction, and scaption motions. In each test, the superior translation of the humeral head was reported. Results: In static testing, SCR significantly reduced humeral superior translation compared with rotator cuff tear at all abduction angles. SCR restored the superior stability back to native at 60° and 90° of abduction, but the humeral head remained significantly and superiorly translated at neutral position and at 30° of abduction. The results of dynamic testing showed a significantly increased superior translation in the injured state at lower elevation angles, which diminished at higher elevation, becoming nonsignificant at elevation >75°. SCR reduced the magnitude of superior translation across all elevation angles, but translation remained significantly different from the intact state up to 60° of elevation. Conclusion: Massive posterosuperior rotator cuff tears increased superior glenohumeral translation when compared with the intact and supraspinatus tendon–insufficient rotator cuff states. SCR using a 3-mm DA partially restored the superior stability of the glenohumeral joint even in the presence of a simulated massive posterosuperior rotator cuff tear in a static and dynamic robotic shoulder model. Clinical Relevance: The biomechanical performance concerning glenohumeral stability after SCR in shoulders with large posterosuperior rotator cuff tears is unclear and may affect clinical outcomes in daily practice.

Humeral Head Translation After a Suprascapular Nerve Block

2013 ◽  
Vol 29 (4) ◽  
pp. 371-379 ◽  
Author(s):  
Jun G. San Juan ◽  
Peter Kosek ◽  
Andrew R. Karduna
Keyword(s):  
Nerve Block ◽  
Humeral Head ◽  
Muscle Activation ◽  
Deltoid Muscle ◽  
Suprascapular Nerve ◽  
Rotator Cuff Tears ◽  
Subacromial Impingement Syndrome ◽  
Muscle Activation Patterns ◽  
Suprascapular Nerve Block ◽  
Head Translation

Subacromial impingement syndrome is the most common shoulder disorder. Abnormal superior translation of the humeral head is believed to be a major cause of this pathology. The first purpose of the study was to examine the effects of suprascapular nerve block on superior translation of the humeral head and scapular upward rotation during dynamic shoulder elevation. The secondary purpose was to assess muscle activation patterns during these motions. Twenty healthy subjects participated in the study. Using fluoroscopy and electromyography, humeral head translation and muscle activation were measured before and after a suprascapular nerve block. The humeral head was superiorly located at 60 degrees of humeral elevation, and the scapula was more upwardly rotated from 30 to 90 degrees of humeral elevation after the block. The differences were observed during midrange of motion. In addition, the deltoid muscle group demonstrated increased muscle activation after the nerve block. The study’s results showed a compensatory increase in humeral head translation, scapular upward rotation, and deltoid muscle activation due to the nerve block. These outcomes suggest that increasing muscular strength and endurance of the supraspinatus and infraspinatus muscles could prevent any increased superior humeral head translation. This may be beneficial in reducing shoulder impingement or rotator cuff tears over time.

scholarly journals Nonarthroplasty Surgical Treatment Options for Massive, Irreparable Rotator Cuff Tears

2018 ◽  
Vol 6 (11) ◽  
pp. 232596711880538 ◽  
Author(s):  
Trevor J. Carver ◽  
Matthew J. Kraeutler ◽  
John R. Smith ◽  
Jonathan T. Bravman ◽  
Eric C. McCarty
Keyword(s):  
Rotator Cuff ◽  
Clinical Outcomes ◽  
Humeral Head ◽  
Latissimus Dorsi ◽  
Rotator Cuff Tears ◽  
Arthroscopic Debridement ◽  
Partial Repair ◽  
Latissimus Dorsi Transfer ◽  
Superior Capsular Reconstruction ◽  
Graft Interposition

Massive, irreparable rotator cuff tears (MIRCTs) provide a significant dilemma for orthopaedic surgeons. One treatment option for MIRCTs is reverse total shoulder arthroplasty. However, other methods of treating these massive tears have been developed. A search of the current literature on nonoperative management, arthroscopic debridement, partial repair, superior capsular reconstruction (SCR), graft interposition, balloon spacer arthroplasty, trapezius transfer, and latissimus dorsi transfer for MIRCTs was performed. Studies that described each surgical technique and reported on clinical outcomes were included in this review. Arthroscopic debridement may provide pain relief by removing damaged rotator cuff tissue, but no functional repair is performed. Partial repair has been suggested as a technique to restore shoulder functionality by repairing as much of the rotator cuff tendon as possible. This technique has demonstrated improved clinical outcomes but also fails at a significantly high rate. SCR has recently gained interest as a method to prohibit superior humeral head translation and has been met with encouraging early clinical outcomes. Graft interposition bridges the gap between the retracted tendon and humerus. Balloon spacer arthroplasty has also been recently proposed and acts to prohibit humeral head migration by placing a biodegradable saline-filled spacer between the humeral head and acromion; it has been shown to provide good clinical outcomes. Both trapezius and latissimus dorsi transfer techniques involve transferring the tendon of these respective muscles to the greater tuberosity of the humerus; these 2 techniques have shown promising restoration in shoulder function, especially in a younger, active population. Arthroscopic debridement, partial repair, SCR, graft interposition, balloon spacer arthroplasty, trapezius transfer, and latissimus dorsi transfer have all been shown to improve clinical outcomes for patients presenting with MIRCTs. Randomized controlled trials are necessary for confirming the efficacy of these procedures and to determine when each is indicated based on specific patient and anatomic factors.

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.

Zoledronic Acid Substantially Improves Bone Microarchitecture and Biomechanical Properties After Rotator Cuff Repair in a Rodent Chronic Defect Model

2020 ◽  
Vol 48 (9) ◽  
pp. 2151-2160
Author(s):  
Jakob E. Schanda ◽  
Claudia Keibl ◽  
Patrick Heimel ◽  
Xavier Monforte ◽  
Stefan Tangl ◽  
...  
Keyword(s):  
Zoledronic Acid ◽  
Rotator Cuff ◽  
Humeral Head ◽  
Bone Microarchitecture ◽  
Intervention Group ◽  
Maximum Load ◽  
Biomechanical Properties ◽  
Rotator Cuff Tears ◽  
Mineral Density ◽  
Load To Failure

Background: Bone mineral density at the humeral head is reduced in patients with chronic rotator cuff tears. Bone loss in the humeral head is associated with repair failure after rotator cuff reconstruction. Bisphosphonates (eg, zoledronic acid) increase bone mineral density. Hypothesis: Zoledronic acid improves bone mineral density of the humeral head and biomechanical properties of the enthesis after reconstruction of chronic rotator cuff tears in rats. Study Design: Controlled laboratory study. Methods: A total of 32 male Sprague-Dawley rats underwent unilateral (left) supraspinatus tenotomy with delayed transosseous rotator cuff reconstruction after 3 weeks. All rats were sacrificed 8 weeks after rotator cuff repair. Animals were randomly assigned to 1 of 2 groups. At 1 day after rotator cuff reconstruction, the intervention group was treated with a single subcutaneous dose of zoledronic acid at 100 µg/kg bodyweight, and the control group received 1 mL of subcutaneous saline solution. In 12 animals of each group, micro–computed tomography scans of both shoulders were performed as well as biomechanical testing of the supraspinatus enthesis of both sides. In 4 animals of each group, histological analyses were conducted. Results: In the intervention group, bone volume fraction (bone volume/total volume [BV/TV]) of the operated side was higher at the lateral humeral head ( P = .005) and the medial humeral head ( P = .010) compared with the control group. Trabecular number on the operated side was higher at the lateral humeral head ( P = .004) and the medial humeral head ( P = .001) in the intervention group. Maximum load to failure rates on the operated side were higher in the intervention group ( P < .001). Cortical thickness positively correlated with higher maximum load to failure rates in the intervention group ( r = 0.69; P = .026). Histological assessment revealed increased bone formation in the intervention group. Conclusion: Single-dose therapy of zoledronic acid provided an improvement of bone microarchitecture at the humeral head as well as an increase of maximum load to failure rates after transosseous reconstruction of chronic rotator cuff lesions in rats. Clinical Relevance: Zoledronic acid improves bone microarchitecture as well as biomechanical properties after reconstruction of chronic rotator cuff tears in rodents. These results need to be verified in clinical investigations.

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 Biomechanics in an Incomplete Versus Complete Supraspinatus Tear: A Cadaveric Study

2020 ◽  
Vol 8 (12) ◽  
pp. 232596712096447
Author(s):  
Danil Rybalko ◽  
Aimee Bobko ◽  
Farid Amirouche ◽  
Dmitriy Peresada ◽  
Awais Hussain ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Humeral Head ◽  
Rotator Cuff Tears ◽  
Vertical Position ◽  
Study Objective ◽  
Supraspinatus Tear ◽  
Complete Tear ◽  
Significant Difference ◽  
Static Conditions ◽  
Biomechanical Comparison

Background: Degenerative and traumatic changes to the rotator cuff can result in massive and irreparable rotator cuff tears (RCTs). Purpose/Hypothesis: The study objective was to conduct a biomechanical comparison between a small, incomplete RCT and a large, complete RCT. We hypothesized that the incomplete supraspinatus (SS) tear would lead to an incremental loss of abduction force and preserve vertical position of the humeral head, while a complete SS tear would cause superior humeral migration, decrease functional deltoid abduction force, and increase passive range of motion (ROM). Study Design: Controlled laboratory study. Methods: Six cadaveric shoulders were evaluated using a custom testing apparatus. Each shoulder was subjected to 3 conditions: (1) intact/control, (2) 50%, full-thickness, incomplete SS tear, and (3) 100%, complete SS tear. Deltoid abduction force, superior humeral head migration, and passive ROM were measured in static conditions at 0°, 30°, and 60° of glenohumeral abduction, respectively. Results: The intact SS resulted in a mean deltoid abduction force of 2.5, 3.3, and 3.8 N at 0°, 30°, and 60° of abduction, respectively. Compared with the intact shoulder, there was no significant difference in mean abduction force seen in the incomplete tear, while the force was significantly decreased by 52% at 30° of abduction in the complete tear ( P = .009). Compared with the incomplete tear, there were significant decreases in abduction force seen in the complete tear, by 33% and 48% (0.9 N and 1.1 N) at 0° and 30° of abduction, respectively ( P = .04 and .004). The intact configuration experienced a mean superior humeral head migration of 1.5, 1.4, and 1.1 mm at 0°, 30°, and 60° of abduction, respectively. The complete tear resulted in a superior migration of 3.0 and 4.4 mm greater than the intact configuration at 0° and 30° of abduction, respectively ( P = .001). There was a 5° and 10° increase in abduction ROM with 50% and 100% tears, respectively ( P = .003 and .03). Conclusion: An incomplete SS tear does not significantly alter the biomechanics of the shoulder, while a large, complete SS tear leads to a significant superior humeral migration, a decreased deltoid abduction force, and a mild increase in passive ROM. Clinical Relevance: Our findings demonstrate the effects of large SS tears on key biomechanical parameters, as they progress from partial tears.

scholarly journals What can the radiological parameters of superior migration of the humeral head tell us about the reparability of massive rotator cuff tears?

PLoS ONE ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. e0231843
Author(s):  
Sang-hoon Park ◽  
Chong Hyuk Choi ◽  
Han-Kook Yoon ◽  
Joong-Won Ha ◽  
Changmin Lee ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Humeral Head ◽  
Rotator Cuff Tears ◽  
Massive Rotator Cuff Tears ◽  
Radiological Parameters
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