Coracoacromial Arch Research Articles

Calcaneo-Achilles Allograft Shoulder Interposition Arthroplasty, Novel Technique for Superior Escape Post Hemiarthroplasty for Failed rTSA: A Case Report

Background: Reverse total shoulder arthroplasties have become common in orthopaedics to treat osteoarthritis in patients with rotator cuff deficiency. Complications of revision hemiarthroplasty from reverse total shoulder arthroplasty include anterosuperior escape, which is defined as a deficiency of the coracoacromial arch that allows the humeral head to migrate proximally. A 58-year-old woman, with superior escape and massive destruction of the shoulder suspensory complex after hemiarthroplasty conversion from a reverse total shoulder arthroplasty (rTSA), presented to our clinic with chronic, disabling shoulder pain. Materials and Methods: The patient underwent a novel salvage procedure with a calcaneo-achilles allograft fixed to the remaining glenoid through the proximal humeral shaft. The goal of this procedure was to preserve as much function in the patient’s arm as possible and reduce her chronic shoulder pain. Results: The patient continued to follow up in our clinic for 1 year postoperatively. She noted complete relief of pain by 6 weeks postoperatively. She also denied any neurologic symptoms in her operative extremity. Her patient-reported outcomes indicated major improvement in her preoperative symptoms. Conclusion: A calcaneal-achilles bone tendon allograft interposition arthroplasty may be a viable solution for failed conversion of rTSA to hemiarthroplasty or problems of end-stage arthritis with superior escape and destruction of the shoulder girdle.

Shoulder Impingement Syndrome, A Common Shoulder Disease: A Comprehensive Review

The shoulder joint is a flexible but unstable joint in the human body. Also, it has complex structures including coracoacromial arch, synovial bursa, head of femur and so on. Based on these traits, shoulder joints have a wide range of activity, but some lesions accompany with, especially some overhand motions like throwing baseball, swimming, lifting the weight above head repetitively. Diversification of pathogenic factors are significant traits of this kind of injury. In addition, lesions of shoulder impingement syndrome (SIS) can occur in multiple locations even happening at same time. Under normal conditions, this type of disease is often delimited by rotator cuff. Because of the complexity of this injury, different tests of diagnosis can be applied, including Hawkins-Kennedy test, Neer sign, Jobe test, Painful arc of motion. For treatment options, these can be divided into conservative treatment including conservative methods and surgical treatment like arthroscopic subacromial decompression (ASD). SIS causes shoulder pain to disrupt and reduce life’s quality of patients. Based on relevant research and literature, this article is designed to offer a general review of the above content.

Anterolateral Acromioplasty Reduces Gliding Resistance Between the Supraspinatus Tendon and the Coracoacromial Arch in a Cadaveric Model

PurposeTo investigate the gliding resistance dynamics between the supraspinatus (SSP) tendon and the coracoacromial arch, both before and after subacromial decompression (anterolateral acromioplasty) and acromion resection (acromionectomy). MethodsUsing four fresh-frozen cadaveric shoulders, acromion shapes were classified (2 type I and 2 type III). Subacromial bursa and coracoacromial ligament maintenance replicated physiological sliding conditions. Gliding resistance was measured during glenohumeral abduction (0° to 60°) in internal rotation (IR) and external rotation (ER). Peak gliding resistance between the SSP tendon and the coracoacromial arch was determined and compared between intact, anterolateral acromioplasty, and acromionectomy. ResultsPeak SSP gliding resistance during abduction in an intact shoulder was significantly higher in IR than in ER (4.1N vs. 2.1N; p<0.001). The mean peak SSP gliding resistance during 0° to 60° glenouhumeral abduction in IR in the intact condition was significantly higher compared with the subacromial decompression condition (4.1N vs. 2.8N; p=0.021) and with the acromionectomy condition (4.1N vs. 0.9N; p<0.001). During 0° to 60° glenohumeral abduction in ER, mean peak SSP gliding resistance in the intact condition was not significantly different compared with the subacromial decompression condition (2.1N vs. 2.0N; p=0.999). The two specimens with a hooked acromion showed significantly higher mean peak SSP gliding resistance during glenohumeral abduction in IR and ER when compared with the two specimens with a flat acromion (IR: 5.8N vs. 3.0N; p=0.006; ER: 2.8N vs. 1.4N; p=0.001). ConclusionsIn this cadaveric study, peak gliding resistance between the SSP tendon and the coracoacromial arch during combined abduction and IR was significantly reduced after anterolateral acromioplasty and was significantly higher in specimens with a hooked acromion. Clinical relevanceThe clinical benefit of subacromial decompression remains unclear. This study suggests that anterolateral acromioplasty might reduce supraspinatus gliding resistance in those with a hooked acromion and in the typical “impingement” position.

Glenohumeral Translations in Overhead Workers with Sub-Acromial Impingement Syndrome: A Review

Introduction: The third most common musculoskeletal condition is shoulder pain with a prevalence of up to 70%. The second most frequent shoulder condition is subacromial impingement syndrome. Impingement can be classified as either anterosuperior or posterosuperior. Faulty posture, altered scapular or glenohumeral kinematics, posterior capsular tightness, and acromial or coracoacromial arch pathology are all potential extrinsic mechanics that can lead to Subacromial impingement syndrome. The purpose of this review is to find the different variation in translation that takes place in the glenohumeral joint in Subacromial impingement syndrome in overhead workers. Methods: We performed a review of the various translations observed in the glenohumeral joint in subacromial impingement syndrome and discussed the evidence-based studies. For the review, an electronic search for relevant articles using PUBMED, Pedro, Research Gate, and Google Scholar databases up to Dec 2022 was done wherein MeSH search terms and free words were used. Articles underwent the selection process and were selected on the basis of inclusion criteria. Articles were selected based on the author's expertise, self-knowledge and reflective practice. Results: The current study included 11 articles that fulfilled the inclusion criteria suggesting that various humeral translations in overhead workers. The above-reviewed studies provided evidence that based on occupational demands abnormal variations occur. Conclusion: This review has provided an overview of the previous and recent literature on humeral head translation seen in sub-acromial impingement. This study concludes that superior translation is more common as compared to anterior-superior translation and posterior-superior translation.

Morphometry of the Acromion Process in Dry Human Scapulae and Its Clinical Implications: A Cross-sectional Study

Introduction: The coracoacromial arch, which extends laterally over the shoulder joint, is formed by the acromion process, coracoid process, and coracoacromial ligament. The acromion process plays an important role in shoulder joint formation. Morphological variations of the acromion process play a key role in determining the subacromial space. Acromioplasty is an important step in rotator cuff repair. Aim: To investigate the morphometry of the acromion process in dry human scapulae and determine the various types of acromion processes. Materials and Methods: An observational cross-sectional study was conducted in the Department of Anatomy at NRI Medical College and General Hospital, Chinakakani, Guntur, Andhra Pradesh, India. The study duration was one year and four months, from November 2020 to March 2022. A total of 100 dry human scapulae (50 right and 50 left) of unknown age and gender were included. Various types of acromion processes were identified. Measurements were taken using a digital vernier caliper (accurate to 0.01 mm) and protractor to measure parameters such as length, breadth, and thickness of the acromion process, acromiocoracoid distance, acromioglenoid distance, height of the coracoacromial arch, acromial slope, and acromial tilt. The data were analysed using Statistical Package for Social Sciences (SPSS) version 24.0. Mean, Standard Deviation (SD), and range were calculated for each morphometric parameter. Results: Three types of acromion processes were observed: type I (31%), type II (48%), and type III (21%). The mean length, breadth, and thickness of the acromion process were 43.21±2.82 mm, 25.48±2.56 mm, and 6.84±1.24 mm, respectively. The mean acromiocoracoid distance, acromioglenoid distance, and height of the coracoacromial arch were 39.87±7.63 mm, 27.34±3.58 mm, and 21.52±1.98 mm, respectively. The mean acromial slope and acromial tilt observed were 32.34±4.62° and 37.46±6.37°, respectively. Conclusion: The present study provides data on the shape, dimensions, slope, tilt, and various distances of the acromion process in dry human scapulae. The majority of the scapulae on both sides exhibited type II acromion process.

Drivers of inpatient hospitalization costs, joint-specific patient-reported outcomes, and health-related quality of life in shoulder arthroplasty for cuff tear arthropathy

Cuff tear arthropathy (CTA) can be successfully treated with various types of shoulder arthroplasty. While reverse total shoulder arthroplasty (RSA) is commonly used to treat CTA, CTA hemiarthroplasty (CTA-H, hemiarthroplasty with an extended humeral articular surface) can also be effective in patients with preserved glenohumeral elevation and an intact coracoacromial (CA) arch. As the value of arthroplasty is being increasingly scrutinized, cost containment has become a priority. The objective of this study was to assess hospitalization costs and improvements in joint-specific measures and health-related quality of life for these two types of shoulder arthroplasty in the management of CTA. Seventy-two patients (39 CTA-H and 33 RSA) were treated during the study time period using different selection criteria for each of the two procedures: CTA-H was selected in patients with retained active elevation, an intact CA arch, and an intact subscapularis, while RSA was selected in patients with pseudoparalysis or glenohumeral instability. The Simple Shoulder Test (SST) was used as a joint-specific patient-reported outcome measure. Improvement in quality-adjusted life years was measured using the Short Form 36. Costs associated with inpatient care were collected from hospital financial records. Univariate and multivariate analyses focused on determining predictors of hospitalization costs and improvements in patient-reported outcomes. Significant improvements in SST and Short Form 36 physical component scores were seen in both groups. Inpatient hospitalization costs were significantly higher in the RSA group than that in the CTA-H group ($15,074±$1614 vs. $10,389±$1948, P<.001), driven primarily by supplies including the cost of the prosthesis ($9005±$2521 vs. $4715±$2091, P<.001). The diagnosis of diabetes was an independent predictor of higher inpatient hospitalization costs for both groups. There were no independent predictors for quality-adjusted life year improvements. SST improvement in the CTA-H group was significantly higher in patients with lower preoperative SST scores. Using a standard algorithm of CTA-H for shoulders with retained active elevation and an intact CA arch and RSA for poor active elevation or glenohumeral instability, both procedures led to significant improvements in health-related quality of life and joint-specific measures. Costs were significantly lower for patients meeting the selection criteria for CTA-H. Further value analytics are needed to compare the relative cost effectiveness of RSA and CTA-H for patients with CTA having retained active elevation, intact CA arch, and intact subscapularis.

A morphometric study of spinoglenoid notch, subcoracoacromial arch, and spinous process of the scapula on shoulder impingement

Introduction: Morphometric study of spinoglenoid notch, coracoacromial arch, and another measurement of the scapulae are required to understand the reason for spasms of common muscle due to supraspinatus tendinitis, nerve compression over the spinoglenoid notch. Therefore, the aim of this study was to discuss the subcoracoacromial arch, deviation of the spinous process, and measurement of the spinoglenoid notch. Materials and Methods: This study was conducted at the Department of Anatomy, Sri Venkateshwaraa Medical College Hospital &amp; Research Centre, Chennai, Tamil Nadu, India on 70 scapulae that include 58 non-articulated scapulae and 12 articulated scapulae. All the measurements were performed with a vernier caliper and the alignment of the spinous process of the scapula was measured with a goniometer. All the measurements are compared on both sides. Results: All the measurements were performed and presented as mean with standard deviation. We found the variation of diameter between the left and right sides. Spinoglenoid notch diameters were noted as anterior to posterior right 2.97 ± 0.37 cm, left 3.06 ± 0.56 cm and medial to lateral right 1.36 ± 0.14 cm, left 1.4 ± 0.08 cm. Subcoracoacromial arch was observed as right 1.85 ± 0.23 cm and left 1.92 ± 0.4 cm. The direction of the spinous process of the scapula was noted as right 21.50º ± 8.50 and left 18.8º ± 7.89. Conclusion: The present morphometric study findings may give a different approach to supraspinatous tendinits, shoulder instability, and dislocation cases due to morphometric changes present in the spinous process, acromion process, glenoid cavity, and spinoglenoid notch of the scapula. These morphometric studies on scapula can help radiologists, orthopedicians, and physiotherapists to plan patient management.

Arthroscopic Subscapularis Augmentation Using the Long Head of the Biceps Tendon for Anterior Shoulder Instability

The limitations of transferring the coracoid process along with the conjoined tendon are coracoacromial arch damage, technical difficulty, and nerve injury. The long head of the biceps tendon (LHBT) proximal transposition technique has a weaker sling effect and a risk of nerve injury. The arthroscopic subscapularis augmentation technique may have risks of shoulder external rotation restriction and subscapularis transection. Herein, we introduce an arthroscopic technique for the transfer of the LHBT for subscapularis augmentation to address these risks. Indications of this technique were patients younger than 45 years of age who engage in competitive sports, require forceful external rotation and abduction, have a related capsule-ligament insufficiency, and have a glenoid bone loss <25%. The steps include detaching the LHBT at the upper edge of the pectoralis major, transecting and braiding the LHBT, establishing a scapular tunnel, placing a guide suture through the upper third of the subscapular and scapular tunnel, passing the LHBT through the established tunnels, and fixating the LHBT. This technique achieves stability of the anterior shoulder by transecting and transferring the distal end of the LHBT to press on the upper third of the subscapularis muscle.

Are scapular morphologic characteristics or rotator cuff tear patterns associated with acetabularization of the coracoacromial arch?

PurposeTo determine whether rotator cuff tear (RCT) patterns and scapular morphologic characteristics are associated with acetabularization of the coracoacromial arch when the remaining rotator cuff cannot stabilize the humeral head centered on the glenoid.MethodsThirty-two consecutive patients incapable of stabilizing the humeral head within the native glenoid were included and divided into 2 groups: unstable glenohumeral fulcrum kinematics (GHFK) group (n = 16; absence of acetabularization of the coracoacromial arch) and captured GHFK group (n = 16; the presence of acetabularization of the coracoacromial arch). Magnetic resonance imaging (MRI) analysis included tear locations, tear extensions (anterior, posterior, and global), and fatty infiltration of the rotator cuff muscles. Plain radiographic and computed tomography image measurements included acromiohumeral distance, critical shoulder angle, lateral acromial angle, acromial index, acromial tilt, acromial slope angle, anterior and posterior acromial coverage, and coracoacromial ligament coverage.ResultsPatient demographic characteristics did not differ significantly (P > .05). No differences in tear patterns were found between patients with unstable GHFK and those with captured GHFK on MRI (P > .05). Scapular morphologic parameter measurements showed significant differences between the unstable and captured GHFK groups: anterior acromial coverage (–5.8 ± 13.8° vs. 13.8 ± 11.3°, P < .001), acromial tilt (34.9 ± 8.9° vs. 26.7 ± 6.2°; P = .005), and acromial slope angle (24.5 ± 8.1° vs. 33.5 ± 7.9°, P = .003).ConclusionScapular morphologic characteristics, rather than RCT patterns, were associated with the development of acetabularization of the coracoacromial arch when the remaining rotator cuff could not stabilize the humeral head. Patients with captured GHFK exhibited larger anterior acromial coverage, smaller acromial tilt, and a more curved acromion than those with unstable GHFK.

LUtarjet-limit unique coracoid osteotomy Latarjet (With video).

BackgroundThe Latarjet procedure is an effective technique for the treatment of recurrent anterior shoulder dislocation with glenoid bone loss. However, the inevitable destruction of the coracoacromial arch may result in humeral head translation. The aim of the study is to introduce a modified Latarjet technique with coracoacromial arch preservation as well as its short term clinical outcomes.MethodsWe propose a novel individualized flexible arthroscopic suture button fixation Latarjet technique called `LUtarjet' with video. Precise measurements of the coracoid process, glenoid deficiency and osteotomy plane were made preoperatively. Only three arthroscopic portals were needed and limit unique coracoid osteotomy was performed with coracoacromial arch preservation. The mini window splitting of the subscapularis was performed from the posterior to the anterior direction and the split window was as small as 8–10 mm in length.ResultsA total of 27 patients (25.6 ± 5.4 years) were included in the study. The average surgical duration was 55.6 ± 6.3 min and the mean follow-up time was 8.1 ± 1.5 months. The functional score was significantly improved at the last follow-up. Radiologic evidence showed that the bone graft healing was placed in the desired position. No complications were found.ConclusionsWe present a fast, easy, accurate, safe arthroscopic ‘LUtarjet’ technique called FEAST that can simplify the arthroscopic Latarjet process and achieve a satisfactory bone graft position and satisfactory short-term clinical outcomes.Level of evidenceIV, case series.

Shoulder Impingement and its Association with Acromial Morphology- A Review

Shoulder with its chronic disability recognized by impingement of the rotator cuff beneath the coracoacromial arch. Varying acromial morphology revealed alterations attributable to mechanical impingement. The undersurface of the anterior part of the acromion and the front lip were always implicated. Extrinsic factors caused impingement and tendonopathy, with the antero-lateral acromion 'impinging' on the superior surface of the rotator cuff. The present review clearly describes the acromial morphology and its role as extrinsic causative factor in shoulder impingement. Treatment options for confirmed impingement range from analgesics and physiotherapy to injectable therapy and, open and arthroscopic surgery. In most studies, the results of arthroscopic subacromial decompression are positive, and data suggest that, the operation minimises the occurrence of rotator cuff injuries when compared to a control group. Complete acromionectomy and lateral acromionectomy yielded dismal results, prompting researchers to investigate the undersurface of the acromion in the development of impingement syndrome. There are however contradictory studies discussing the role of extrinsic and intrinsic causative factors of impingement.

Immunologic Contributions Following Rotator Cuff Injury and Development of Cuff Tear Arthropathy.

Rotator cuff tear arthropathy (RCTA) describes a pattern of glenohumeral degenerative changes following chronic rotator cuff tears that is characterized by superior humeral head migration, erosion of the greater tuberosity of the humeral head, contouring of the coracoacromial arch to create a socket for the humeral head, and eventual glenohumeral arthritis. Acute and chronic inflammatory changes following rotator cuff tears are thought to contribute to cartilage damage, muscle fibrosis, and fatty infiltration in the glenohumeral joint. In vitro animal studies targeting various inflammatory modulators, including macrophages, insulin-like growth factor-I, and transforming growth factor-beta pathways, provide promising therapeutic targets to improve healing after rotator cuff tears. The role of platelet-rich plasma in the treatment and prevention of RCTA has been investigated, with conflicting results.

Morphometry and Morphology of Acromian Process of Scapula

Introduction: The acromian process of scapula is project forward from lateral end of spinous process ofscapula. Coracoacromial ligament is extend between coracoid process and acromian process ,it help information of coracoacromial arch, anatomy of this region is important for better understanding of pathologyregarding subacromial bursa ,impingement syndrome .Materials and Methods: Present study was carried out on 74 dry, adult human scapulae 38 left side and 36right side from teaching collection of anatomy department ,sex of the specimen not known ,Scapular length,width ,acromian process length ,width, thickness ,coracoacromial distance ,acromioglenoid distance wasmeasured with the help of vernier caliper, we also found different shape of acromian process.Results: We observed 74 scapula out of them 38 scapula are of type –I which was 51.35%,13 scapulaof type –II which was 17.57%, 23 scapula of type –III which was 31.08%, we observed mean valueacromian length was 4.50±0.52cm, width of acromian process was 2.10±0.26cm, thickness of acromianprocess was 0.78±0.10cm ,acromicoracoid distance was 3.45±0.53cm, distance between acromianprocess and supraglenoid tubercle was 2.48±0.40cm.Conclusion: These findings suggest that the difference in various parameters related to acromian processhelp in better understanding of anatomy and pathology of coracoacromial arch ,rotator cuff and also helpfulto other clinician.

Association between shoulder coracoacromial arch morphology and anterior instability of the shoulder

BackgroundGlenohumeral instability is a common condition of the shoulder. Glenoid bone loss and humeral head bone loss are well recognized as risk factors for recurrent instability. There are few studies in the literature that examine the role of coracoacromial arch anatomy in the pathogenesis of glenohumeral instability. Previous reports found an association between posterior acromial coverage (PAC) and posterior instability. We hypothesize that coracoacromial arch anatomy is related to anterior shoulder instability.MethodsIn this retrospective cohort study, 50 patients with unidirectional anterior shoulder instability were matched to a control group of 50 glenohumeral arthritis patients without any history of shoulder instability. Radiographic measurements of the coracoacromial arch anatomy were made: shoulder arch angle, scapular Y angle, anterior coracoid tilt (ACT), posterior acromial tilt, anterior acromial coverage angle, PAC angle, coracoid height, posterior acromial height, and critical shoulder angle were determined using standard lateral scapular and anteroposterior radiographs.ResultsLogistic regression analyses found a significant association between the presence of anterior instability and flatter coracoacromial arch angles (mean, 124.1°) vs. the arthritis control group (mean, 120.6°) (odds ratios [OR] = 1.113; 95% confidence interval [CI] = 1.039-1.191; P = .002). There was a significant association between anterior instability and ACT (OR = 1.144; 95% CI = 1.053-1.243; P = .001), whereas a negative association was found between anterior instability and PAC (OR = 0.909; 95% CI = 0.853-0.969; P = .004) and posterior acromial tilt (OR = 0.878; 95% CI = 0.773-0.998; P = .046). Lower critical shoulder angle values were associated with the arthritis group (28.2° vs. 33.9°) (OR = 1.555; 95% CI = 1.202-2.012; P = .001).ConclusionsShoulder coracoacromial arch morphology may play a role in the stability of the shoulder joint and development of recurrent anterior instability. Shoulders with a decreased shoulder arch angle, a less contained and flatter coracoacromial arch and larger ACT, were associated with anterior instability. This study identifies the shoulder coracoacromial arch angle and anterior coracoid tile angles as risk factors for anterior shoulder instability. Our findings suggest that measuring these angles may help orthopedic surgeons understand the risk of anterior instability and analyze risk factors to improve clinical decision making.

Arthroscopic Outside-In Rotator Interval Release

Rotator interval release is an important procedure used in many shoulder operations. It is currently performed through an intra-articular approach, which may result in incomplete release or tissue removal. Here, we introduce an outside-in rotator interval release technique for complete rotator interval tissue removal, which is performed mainly through the lateral portal and a distal anterior portal under the coracoacromial arch. This technique can be used for many shoulder conditions, such as severe joint contracture or fibrosis, fixed shoulder dislocation, or disorders of the long head of the biceps. Our experience indicates that this technique is easy, effective, and capable of addressing even the most difficult shoulder conditions. We believe that adoption of this technique by surgeons can facilitate the success of many shoulder operations.

Shoulder biomechanics in normal and selected pathological conditions.

The stability of the glenohumeral joint depends on soft tissue stabilizers, bone morphology and dynamic stabilizers such as the rotator cuff and long head of the biceps tendon. Shoulder stabilization techniques include anatomic procedures such as repair of the labrum or restoration of bone loss, but also non-anatomic options such as remplissage or tendon transfers.Rotator cuff repair should restore the cuff anatomy, reattach the rotator cable and respect the coracoacromial arch whenever possible. Tendon transfer, superior capsular reconstruction or balloon implantation have been proposed for irreparable lesions.Shoulder rehabilitation should focus on restoring balanced glenohumeral and scapular force couples in order to avoid an upward migration of the humeral head and secondary cuff impingement. The primary goal of cuff repair is to be as anatomic as possible and to create a biomechanically favourable environment for tendon healing.Cite this article: EFORT Open Rev 2020;5:508-518. DOI: 10.1302/2058-5241.5.200006

Immediate Effect of Mobilization vs Myofascial Release on Pain and Range of Motion in Patients with Shoulder Impingement Syndrome: A Pilot Randomized Trial

Background: Shoulder Impingment Syndrome (SIS) is a generic term for injury of structures in the subacromial space, regarded as anatomic abnormalities of the coracoacromial arch or humeral head. SIS is thought to be associated with articular or myofascial dysfunction, various researches have been done on rehabilitation of shoulder impingement by addressing either osseous structure or myofascial structure and found to be effective. But no studies could retrieve to compare these two. Objective: To compare the immediate effects of mobilization vs myofascial release on pain and range of motion in subjects with shoulder impingement syndrome. Study Design: A pilot randomized trial. Method: 20 subjects with SIS of both the genders were randomly divided into two groups: group 1 (n=10), which received MFR on active muscle trigger points and group 2 (n=10), received mobilization of AC joint along with Thoracic spine for four sessions. The outcome measures shoulder pain and range of motions measured at the baseline, end of 1st session and 1st week. Result: The result of this present study showed that participants of both the groups experienced significant improvement in all the outcomes (p<0.05), but the MFR group was superior in reducing pain intensity. Conclusion: The study concluded that MFR can be used as an initial treatment for pain reduction among SIS individuals.

To Study the Morphological Changes of Coracoacromial Arch in Various Shoulder Disorders

To Study the Morphological Changes of Coracoacromial Arch in Various Shoulder Disorders

Shoulder mechanical impingement risk associated with manual wheelchair tasks in individuals with spinal cord injury

BackgroundMost individuals with spinal cord injury who use manual wheelchairs experience shoulder pain related to wheelchair use, potentially in part from mechanical impingement of soft tissue structures within the subacromial space. There is evidence suggesting that scapula and humerus motion during certain wheelchair tasks occurs in directions that may reduce the subacromial space, but it hasn't been thoroughly characterized in this context. MethodsShoulder motion was imaged and quantified during scapular plane elevation with/without handheld load, propulsion with/without added resistance, sideways lean, and weight-relief raise in ten manual wheelchair users with spinal cord injury using biplane fluoroscopy and computed tomography. For each position, minimum distance between rotator cuff tendon insertions (infraspinatus, subscapularis, supraspinatus) and the coracoacromial arch was determined. Tendon thickness was measured with ultrasound, and impingement risk scores were defined for each task based on frequency and amount of tendon compression. FindingsPeriods of impingement were identified during scapular plane elevation and propulsion but not during pressure reliefs in most participants. There was a significant effect of activity on impingement risk scores (P < 0.0001), with greatest impingement risk during scapular plane elevation followed by propulsion. Impingement risk scores were not significantly different between scapular plane elevation loading conditions (P = 0.202) or propulsion resistances (P = 0.223). The infraspinatus and supraspinatus tendons were both susceptible to impingement during scapular plane elevation (by acromion), whereas the supraspinatus was most susceptible during propulsion (by acromion and coracoacromial ligament). InterpretationThe occurrence of mechanical impingement during certain manual wheelchair tasks, even without increased load/resistance, demonstrates the importance of kinematics inherent to a task as a determinant of impingement. Frequency of and technique used to complete daily tasks should be carefully considered to reduce impingement risk, which may help preserve shoulder health long-term.

Critical scapula motions for preventing subacromial impingement in fully-tethered front-crawl swimming

ABSTRACT The aims were to quantitatively describe the coordinated motions of the scapula and humerus during fully tethered front-crawl strokes and to test the hypothesis that scapular motion functions to reduce the risk of subacromial compression. An electromagnetic tracking device was used to record the kinematics of the thorax, humerus, and scapula on the dominant side in 17 collegiate swimmers. Because evidence suggests that compressive force develops under the coracoacromial arch when the arm elevated above 90º of arm elevation is maximally internally rotated, such shoulder configurations were measured for each participant. A series of scapulohumeral angles measured with this procedure were compared with the corresponding angles exhibited during fully tethered front-crawl swimming to identify the scapulohumeral angles indicative of subacromial compression. Additional comparison was performed without taking the scapular motion into account. Scapulohumeral angles indicative of subacromial compression were observed in 15 participants, accounting for 7.7 ± 7.1% of stroke cycle time. This duration was significantly less than the corresponding duration identified without having taken the scapular motion into account (22.6 ± 13.8% of stroke cycle time). The difference was due primarily to the unique movements of the scapular to accommodate demands imposed by stroke motions, and this supported the hypothesis.