Acromion morphology and prevalence of rotator cuff tear: A systematic review and meta-analysis

Occupational Stress as a Possible Risk Factor for Rotator Cuff Damage - Systematic Review and Meta-analysis

PURPOSE

In September 2021, the Federal Ministry of Labour and Social Affairs in Germany (BMAS) recommended recognising rotator cuff lesions caused by occupational long-term overhead work, repetitive movements, hand-arm-vibration and carrying and lifting heavy loads as an occupational disease. To gain a more detailed understanding of the correlation between occupational risk factors and lesions of the rotator cuff, a systematic literature review was carried out to determine their influence on the development of rotator cuff disease.

MATERIAL AND METHOD

A systematic literature review was used to search in the databases PubMed, Cochrane and Web-of-Science for papers dealing with occupational shoulder load and associated shoulder disorders. The influence of overhead work, repetitive movements, hand-arm-vibrations and carrying and lifting heavy loads were examined.

RESULTS

58 studies were read in full text, of which 13 papers were included in the meta-analysis. In all risk factors, a significant association can be found with the strongest dose-response relationship in "overhead work" and "repetitive movements": overhead work: 2.23 (95% CI 1.98-2.52), repetitive movements: 2.17 (95% CI 1.92-2.46), hand-arm-vibration: 1.59 (95% CI 1.13-2.23), carrying and lifting heavy loads: 1.57 (95% CI 1.15-2.15).

CONCLUSION

Although a significant effect could be shown in our study for all the four risk factors examined, due to the low number of studies with high-quality study design and insufficient pathophysiological explanation for the development of a rotator cuff disease in these mechanical activities, no reliable correlation can currently be established.

Does Morphology of the Shoulder Joint Play a Role in the Etiology of Rotator Cuff Tear?

BACKGROUND

The etiology of rotator cuff tears (RCTs) have been investigated for years and many underlying causes have been identified. Shoulder joint morphology is one of the extrinsic causes of RCTs.

AIM

Morphometric measurements on MRI sections determined which parameters are an important indicator of RCT in patients with shoulder pain. The aim of this study was to determine the risk factors in the etiology of RCTs by evaluating the shoulder joint morphology with the help of previously defined radiological parameters.

METHOD

Between January 2019-December 2020, 408 patients (40-70 years old) who underwent shoulder MRI and met the criteria were included in the study. There were 202 patients in the RCT group and 206 patients in the control group. Acromion type, acromial index (AI), critical shoulder angle (CSA), acromiohumeral distance (AHD), lateral acromial angle (LAA), acromial angulation (AA), acromion-greater tuberosity impingement index (ATI), and glenoid version angle (GVA) were measured from the MRI images of the patients.

RESULTS

AI (0.64 vs. 0.60, p = 0.003) CSA (35.3° vs. 32.4°, p = 0.004), ATI (0.91 vs. 0.83, P < 0.001), and AA (13.6° vs. 11.9°, p = 0.011) values were higher in the RCT group than in the control group and the difference was significant. AHD (8.1 mm vs. 9.9 mm, P < 0.001), LAA (77.2° vs. 80.9°, p = 0.004) and GVA (-3.9° vs. -2.5°, P < 0.001) values were lower in the RCT group than in the control group, and again the difference was significant. According to the receiver operating characteristic curve analysis, the cutoff values were 0.623 for AI and 0.860 for ATI.

CONCLUSION

Acromion type, AI, CSA, AHD, LAA, AA, ATI, and GVA are suitable radiological parameters to evaluate shoulder joint morphology. High AI, CSA, AA, ATI, GVA and low AHD and LAA are risk factors for RCT.

Rotator Cuff Tears to Shoulder Instability: The Relationship Between Acromial Morphology and Shoulder Pathology

» The acromion is a well-studied region of the scapula that has demonstrated substantial relationships to various shoulder pathologies.» Abnormal acromial morphology is associated with rotator cuff pathology, and our understanding of this risk factor inspired acromioplasty as an adjunctive treatment for rotator cuff tears.» The acromion is linked closely to shoulder kinematics and biomechanics, as it serves as the origin for the deltoid muscle.» In degenerative shoulder disease, eccentric glenohumeral osteoarthritis has been associated with a higher, flatter acromial roof.» Increasing literature is emerging connecting morphology of the acromion with shoulder instability.

Evaluation of the acromion variants in MRI and their association with rotator cuff injuries in non-traumatic patients

Purpose

Understanding demographic and MRI parameters with determinant role in rotator cuff tearing (RCT) is required to predict outcomes and select more appropriate treatment in patients with non-traumatic shoulder pain. This study aimed to survey the association of rotator cuff tears with these factors.

Methods

We performed this cross-sectional study on patients referred to Kashani Hospital with non-traumatic shoulder pain suspected of rotator cuff injuries from April 2020 to February 2021. We obtained their demographic data and MRI from electronic hospital records. After that, two radiologists reviewed MRI and recorded data. We employed the SPSS 23 software to organize the obtained results and statistical evaluations.

Results

371 subjects, with the age of 48.61 ± 14.89 years, were included in our study, and 50% of them were male. The flat and down-sloping acromion and partial tearing of the supra and infraspinatus tendons were more frequent than the others. Gender could not consider as a determinant factor for the severity of tendon injuries, acromion types and variants. The relation of age to acromion morphology and the tendinopathy severity was significant. Remarkably, down-sloping acromion was higher at all the acromion shapes; however, it makes no difference in the level of supra and infraspinatus involvement. Moreover, we found that partial tearing was higher in all acromion types, except concave. This distribution was significant only for supraspinatus tears.

Conclusion

The clinical decision is the most important step in patients with RCT and MRI prognostic factors, which are helpful to improve the management of the cases. RCT in older patients and down-slope acromion was more severe than the others. According to the previous studies, acromion morphology (as an important determinant factor) in RCT could be influenced by age, as well.

Average Indian Glenoid Sizes Are Smaller than All Commercially Available Glenoid Components: A Systematic Review

Background

Despite the variability in glenoid sizes geographically, most of the currently available commercial glenoid component designs are based on the glenoid parameters of the Caucasian population which may not be suitable for the Indian population due to a mismatch between the prosthesis and native anatomy. The aim of the present study is to systematically review the literature to determine the average glenoid anthropometric parameters in the Indian population.

Methods

A comprehensive literature search was conducted using preferred reporting items for systematic reviews and meta-analyses guidelines in the PubMed, EMBASE, Google Scholar, and Cochrane Library databases from the date of inception to May 2021. Any observational study conducted on the Indian population measuring the glenoid diameters, glenoid index, version, inclination, or any other glenoid measurements were included in the review.

Results

A total of 38 studies were included in this review. The glenoid parameters were assessed on intact cadaveric scapulae in 33 studies, on 3DCT in three studies, and 2DCT in one study. The pooled average of glenoid dimensions are as the following- the superoinferior diameter or height was 34.65 mm, anteroposterior1 diameter or maximum width was 23.72 mm, anteroposterior2 diameter or maximum width of the upper part of the glenoid was 17.05 mm, the glenoid index was 67.88, and the glenoid version was 1.75-degree retroversion. Males were having a mean height of 3.65 mm and maximum width of 2.74 mm larger than the females. A subgroup analysis revealed no significant difference between different parts of India in glenoid parameters.

Conclusion

The glenoid dimensions in the Indian population are smaller compared to the average European and American populations. The average glenoid maximum width of the Indian population is 1.3 mm smaller than the minimum glenoid baseplate size available in reverse shoulder arthroplasty. Glenoid components specific to the Indian market need to be designed to reduce glenoid failure attributable to the above findings.

Level of evidence

III.

In Situ-Forming Fibrin Gel Encapsulation of MSC-Exosomes for Partial-Thickness Rotator Cuff Tears in a Rabbit Model: Effectiveness Shown in Preventing Tear Progression and Promoting Healing

BACKGROUND

Current nonoperative treatments for partial-thickness rotator cuff tears (PTRCTs) have limited effectiveness in preventing tear progression or promoting tendon healing. This study aimed to establish a rabbit model using in situ-forming fibrin gel containing adipose stem cell-derived exosomes (ASC-Exos/fibrin) to treat PTRCTs.

METHODS

Fifty-six rabbits (112 shoulders) were included in this study and assigned to 4 groups: the control group (32 shoulders; PTRCTs without treatment), the fibrin group (32 shoulders; PTRCTs treated with fibrin gel), the ASC-Exo/fibrin group (32 shoulders; PTRCTs treated with ASC-Exos/fibrin), and the sham group (16 shoulders; sham surgery). Bilateral, 50%-thickness, bursal-side PTRCTs of 1 mm (depth) × 3 mm (width) × 5 mm (length) on the supraspinatus tendon were established by a number-11 scalpel blade, with accuracy of the measurement ensured by a digital vernier caliper. At 6 and 12 weeks postoperatively, gross observation, measurement of the thickness of residual supraspinatus tendons, and histological and biomechanical analyses were performed to analyze tendon repair.

RESULTS

At 12 weeks postoperatively, the tendon thickness in the ASC-Exos/fibrin group (mean and standard deviation, 1.63 ± 0.19 mm) was significantly greater than in the control group (0.85 ± 0.09 mm) (p < 0.0001) and fibrin group (1.16 ± 0.17 mm) (p < 0.0001). The histological score in the ASC-Exos/fibrin group (6.25 ± 0.53) was significantly better than in the control group (11.38 ± 0.72) (p < 0.0001) and fibrin group (9.00 ± 0.54) (p < 0.0001). Overall, immunohistochemical staining of types-I and III collagen and biomechanical testing also showed ASC-Exos/fibrin to be more effective in repairing PTRCTs than fibrin alone and no treatment.

CONCLUSIONS

Local administration of in situ-forming ASC-Exos/fibrin effectively facilitated the healing of bursal-side PTRCTs in rabbits. This approach may be a candidate for the nonoperative management of PTRCTs.

CLINICAL RELEVANCE

Ultrasound-guided injection of ASC-Exos/fibrin may be a novel nonoperative strategy to treat PTRCTs.

Acromial fractures following reverse shoulder arthroplasty: the role of the acromial morphology and a comparison of clinical outcomes

BACKGROUND

The purpose was to evaluate the relationship between acromial morphology and the location of acromial fractures following reverse shoulder arthroplasty and determine whether fracture location and displacement impact clinical outcomes.

METHODS

We performed a multicenter retrospective review of reverse shoulder arthroplasties complicated by acromial fractures. Radiographs were compared to determine the differences in acromial morphology, as well as fracture orientation and pattern, between patients with Levy type I (n = 17) and Levy type II (n = 25) fractures. Patients with a minimum of 2 years' follow-up were selected to examine the association between clinical outcomes and fracture location and displacement. Twenty-two patients were stratified based on whether they achieved the minimal clinically important difference (MCID) in the American Shoulder and Elbow Surgeons score (20 points). The groups were then compared regarding fracture location and displacement using measurements such as the acromiohumeral distance.

RESULTS

The Levy type I group had a higher acromial slope than the Levy type II group (127° vs. 117°, P < .001). Levy type I fractures had a transverse pattern occurring in the coronal plane, whereas Levy type II fractures had an oblique pattern occurring in the sagittal plane (P < .001). At final follow-up, 12 of 22 patients (55%) achieved the MCID. Those who did not achieve the MCID had more displaced fractures including a lower acromiohumeral distance (8 mm vs. 20 mm, P = .007). There was no difference in the distribution of Levy type I and type II fractures based on the MCID cutoff (P = .093).

CONCLUSION

An increased acromial slope is associated with transverse fractures in the Levy I region, whereas a lower acromial slope is associated with oblique fractures in the Levy II region. Overall, 55% of patients achieved the MCID at mid-term follow-up. The outcomes of those who did not achieve the MCID became worse postoperatively, and this was associated with increased fracture displacement.

A high acromion-greater tuberosity impingement index increases the risk of retear after arthroscopic rotator cuff repair

BACKGROUND

No evaluation has been done on the relationship of the acromion-greater tuberosity impingement index (ATI) with retear after arthroscopic rotator cuff repair (ARCR). Our purpose was to evaluate whether a higher ATI is associated with retear after ARCR.

METHODS

132 patients received ARCR and underwent MRI scan at a one year follow-up to assess tendon healing, and the findings were graded no retear (NR), partial-thickness retear (PR) or full-thickness retear (FR). The ATI, the critical shoulder angle (CSA), acromion index (AI) and lateral acromial angle (LAA) were measured with postoperative radiographs. Functional scores were obtained preoperatively and at a one year follow-up.

RESULTS

Postoperative Constant scores and ASES scores were significantly different between groups with inferior outcomes in the FR group (p < 0.05 for all). The UCLA score was significantly better in the NR group compared with the PR and FR groups (p < 0.05), and in the PR group compared with the FR group (p < 0.05). For ATI and CSA, the values of the PR and FR groups were larger than the NR group (p < 0.05 for all), but there were no significant differences between the PR and FR groups (p > 0.05 for all). No significant differences were observed with regard to the AI and LAA (p > 0.05, respectively). The repair integrity was positively related to the ATI (0.304, p < 0.05) and CSA (0.252, p < 0.05), but not related to the AI or LAA (p > 0.05 for both). ATI was not related to any functional scores (p > 0.05 for all).

CONCLUSION

This study revealed that the ATI was positively related to rotator cuff retear. Patients with retears had significantly greater ATIs after ARCR. Level of Evidence: III, case-control study.

The Critical Appraisal Tool for Anatomical Meta-analysis (CATAM): A framework for critically appraising anatomical meta-analyses

The hallmark of evidence-based medicine is the meta-analysis (MA). For much of its rich history, the field of anatomy has been dominated by descriptive, cadaveric studies. In the last two decades, quantitative measurements and statistical analyses have frequently accompanied such studies. These studies have directly led to the publication of anatomical MAs, which have ushered in the exciting field of evidence-based anatomy. Although critical appraisal tools exist for clinical MAs, none of them are specifically tailored for anatomical MAs. Therefore, the purpose of this paper is to provide a framework by which clinical anatomists and others can critically appraise anatomical MAs using the Critical Appraisal Tool for Anatomical Meta-analysis (CATAM). Using a running example from a recently published MA, we show how to use the CATAM rubric in a step-by-step fashion. Each scored section of the CATAM rubric is summated into a total score (maximum 50 points). This score is then referenced to a conversion chart, which assigns a qualitative value to the MA in a range from "very good" to "poor." Future studies can investigate the interrater reliability of the instrument, and possibly subject the CATAM rubric to a Delphi panel. As anatomical MAs become more commonplace at surgical grand rounds and journal clubs in academic medical centers throughout the world, we hope that the CATAM rubric can help facilitate meaningful discussions about the quality and clinical relevance of anatomical MAs. This article is protected by copyright. All rights reserved.

Use of biologics in rotator cuff disorders: Current concept review

Poor tendon to bone healing following rotator cuff repair has led to the continued interest and investigation into biological augmentation. The biology of tendinopathy is not fully understood and consequently the availability of disease modifying therapeutic targets is limited. A ceiling of benefit has been reached by mechanical optimisation of rotator cuff repair and thus, in order to improve healing rates, a biological solution is required. This review focuses on the strategies to biologically augment rotator cuff disorders with an emphasis on rotator cuff repair. Leucocyte rich platelet rich plasma has been shown to improve healing rates without clinically relevant improvements in outcome scores. Similarly, improved healing rates have also been reported with bone marrow stimulation and in long-term follow-up with bone marrow concentrate. Extracellular matrix (ECM) and synthetic scaffolds can increase healing through mechanical and or biological augmentation. A potential third category of scaffold is bio-inductive and has no mechanical support. Studies involving various scaffolds have shown promising results for augmentation of large to massive tears and is likely to be most beneficial when tendon quality is poor, however level I evidence is limited.

WITHDRAWN: Higher coracoacromial ligament thickness, critical shoulder angle and acromion index are associated with rotator cuff tears in patients who undergo arthroscopic rotator cuff repair

PURPOSE

To evaluate the effect of several shoulder anatomical parameters in the development of rotator cuff tear (RCT).

METHODS

Between 2014 and 2018, all consecutive patients who underwent arthroscopic rotator cuff repair due to full-thickness rotator cuff tear with a minimum 2-year follow-up were identified. Inclusion criteria were (1) age>18 years, (2) patients with degenerative RCT, (3) full-thickness RCTs, (4) patients underwent arthroscopic RCR due to unresponsive conservative treatment, (5) minimum 2-year follow-up period. Exclusion criteria were traumatic RCT, history of previous shoulder surgery, shoulder deformity, neurologic or neuromuscular dysfunction, glenohumeral and/or acromioclavicular joint arthritis, cuff-tear arthropathy, history of fracture around shoulder and inadequate or low-quality magnetic resonance images (MRI). Acromion index (AI), Critical shoulder angle (CSA), Coracoacromial ligament (CAL) thickness, Subacromial space (SS) width, Acromiohumeral distance (AHD), CAL/SS ratio, Lateral acromial angle (LAA) and glenoid version angle (GVA) parameters were measured on MRI. Intra- and interobserver reliability were measured. Regression analysis was used to evaluate the association between anatomical parameters and RCT development. Receiver operating curves (ROC) were created for independent risk factors. The correlation between measurement parameters were evaluated.

RESULTS

There were 1029 patients met the inclusion criteria. After exclusions, 437 patients were included. Age- and sex matched 437 patients without any shoulder pathologies were selected as control group. There was almost perfect intra- (ICC>0.85) and interobserver (ICC> 0.81) reliability regarding all measurement parameters. There was significant difference between RCT group and control group regarding AI (0.67±0.07 vs. 0.61±0.08, p<0.001), CSA (33.58±3.93 vs. 31.50±4.01, p<0.001), CAL thickness (1.81±0.64 vs. 1.53±0.50, p<0.001), CAL/SS ratio (0.29±0.14 vs. 0.23±0.10, p<0.001) and GVA (-16.69±6.69 vs. -15.37±5.95, p=0.002) parameters. AI (OR: 1.998, P<0.001), CAL thickness (OR: 2.801, p<0.000) and CSA (OR: 3.055, p<0.001) were found to be independently associated with the increased risk of RCT development. Area under curve (AUC) of the AI, CSA, and CAL thickness were 71.4%, 71.3%, and 70.2%, respectively. Cut-off values for AI, CSA, and CAL thickness were 0.62, 36.4° and 1.47 mm, respectively. There was significantly positive strong correlation between AI and CSA (p<0.001, r=0.814).

CONCLUSION

Higher AI, CSA and CAL thickness independently associated with full-thickness RCT development. In clinical practice, these parameters may be useful in the prediction of rotator cuff rupture.

The biomechanics of the rotator cuff in health and disease - A narrative review

The rotator cuff has an important role in the stability and function of the glenohumeral joint. It is a complex anatomic structure commonly affected by injury such as tendinopathy and cuff tears. The rotator cuff helps to provide a stabilising effect to the shoulder joint by compressing the humeral head against the glenoid cavity via the concavity compression mechanism. To appreciate the function of the cuff it is imperative to understand the normal biomechanics of the cuff as well as the mechanisms involved in the pathogenesis of cuff disease. The shoulder joint offers a wide range of motion due to the variety of rotational moments the cuff muscles are able to provide. In order for the joint to remain stable, the cuff creates a force couple around the glenohumeral joint with coordinated activation of adjacent muscles, which work together to contain the otherwise intrinsically unstable glenohumeral joint and prevent proximal migration of the humerus. Once this muscular balance is lost, increased translations or subluxation of the humeral head may result, leading to changes in the magnitude and direction of the joint reaction forces at the glenohumeral joint. These mechanical changes may then result in a number of clinical presentations of shoulder dysfunction, disease and pain. This narrative review aims to highlight the importance of functional rotator cuff biomechanics whilst assessing the kinetics and kinematics of the shoulder joint, as well as exploring the various factors involved in cuff disease.

The acromion-greater tuberosity impingement index: A new radiographic measurement and its association with rotator cuff pathology

PURPOSE

Several radiographic parameters describe humeral head coverage by the acromion. We describe a new radiographic measurement, the acromion-greater tuberosity impingement index (ATI), and its ability to predict rotator cuff pathology.

METHODS

The ATI was measured with magnetic resonance imaging (MRI) and X-ray analysis in 83 patients with rotator cuff pathology and 76 patients with acute rotator cuff tears. The lateral acromial angle (LAA), acromion type, the acromion index (AI) and the critical shoulder angle (CSA) were measured to assess their correlations with the ATI. Receiver operating characteristic (ROC) curves were used to predict degenerative rotator cuff pathology. The change in the ATI after acromion surgery was evaluated in both groups.

RESULTS

According to the ROC curves, the ATI is a good predictor of degenerative rotator cuff pathology on both X-ray (cut-off, 0.865) and MRI (cut-off, 0.965). Patients with degenerative rotator cuff pathology had a significantly higher average ATI compared to the trauma group (p = 0.001 for X-ray and MRI). The degenerative group had a significantly lower LAA (p = 0.001) and a higher ratio of type III acromion (p = 0.035) than the trauma group. The ATI on X-ray was negatively related to the LAA and positively related to the AI, the CSA and acromion type (each p < 0.05). The ATI on MRI was negatively related to the LAA and positively related to the AI and acromion type (each p <0.05). More patients in the degenerative group than the trauma group needed acromioplasty or acromion decompression (p < 0.05). The ATI on MRI was significantly lower after acromion surgery compared to before surgery in both groups (p < 0.05).

CONCLUSION

The ATI is a good predictor of degenerative supraspinatus tendon tears or subacromial impingement syndrome. The ATI on MRI is more accurate and can precisely guide acromion surgery.

Prediction of Rotator Cuff Injury Associated with Acromial Morphology: A Three-Dimensional Measurement Study

Objective

To analyze the relationship between the acromial morphology and the related rotator cuff injury using a three‐dimensional (3D) measurement technology.

Methods

For the present study, 226 patients (113 men and 113 women) who underwent shoulder Coarthroscopy from June 2015 to December 2019 at the Department of Orthopedics at our hospital were selected retrospectively. A total of 113 shoulder joints of age‐matched healthy people were selected as the control group. A 3D model coordinate system of the shoulder was established based on CT scan images. Patients were grouped according to the condition of the rotator cuff injury during surgery. The patients whose rotator cuff tear site corresponded to the 3D osseous proliferative structure of the acromion were classified into the impingement injury group (II group). The other patients were classified into the non‐impingement injury group (NII group). The acromiohumeral interval (AHI), the acromial anterior protrusion (AAP), the acromial inferior protrusion (AIP), the acromioclavicular angle (AC angle), the distance from the most medial edge of the acromial anterolateral protrusion (AALP) to the most lateral point of acromion (MLPA) (a), the distance from the most posteromedial edge of the AALP to the MLPA (b), the anteroposterior diameters of the AALP (c), and the proportion of anteroposterior diameters of AALP to the anteroposterior diameters of acromion, (c/c + d) × 100(%), were measured using the 3D shoulder model.

Results

The results of the intraobserver (<5%) and interobserver variability (>87%) analysis found the parameters to have high intraobserver and interobserver concordance. There were no significant differences in age among the control group, the NII group, and the II group (P = 0.8416). There were significant differences in AAP among the three groups (P = 0.0374). The results were the same for men and women, respectively. The AAP in the control group and the NII group did not show a difference, while the AAP in the II group was increased by 26.9% (P = 0.015) and 25% (P = 0.023), respectively, compared with the NII group and the control group. AHI, AIP, and AC angles did not show significant differences among the three groups (P > 0.05). The (a) and (b) of the II group were significantly larger than those of the NII group; P‐values were 0.0119 and 0.0003, respectively. The (a) and (b) in patients with rotator cuff injuries were larger than in the normal population (P < 0.05). The above results were the same for men and women. This suggested that the larger width of the AALP might cause the related rotator cuff injury. The (c/c + d) in the II group was significantly larger than those in the control and the NII groups, with P‐values of 0.0005 and 0.0021, respectively. The risk of rotator cuff injury due to subacromial impingement was increased when the maximum width of the medial–lateral edge of the AALP exceeded 16.8 mm (17.4 mm in men, 15.1 mm in women), the maximum width of the posterior edge of the AALP exceeded 12.9 mm (13.8 mm in men,12.7 mm in women), or the anteroposterior diameters of the AALP exceeded the anteroposterior diameters of the acromion by 33.5%.

Conclusion

We could predict the occurrence and development of the related rotator cuff injury in symptomatic patients with specific 3D changes in their acromion and intervene in the acromion of such patients as early as possible to prevent possible rotator cuff injuries in the future.

Acromial morphology is not associated with rotator cuff tearing or repair healing

BACKGROUND

The purposes of this study were to determine whether acromial morphology (1) could be measured accurately on magnetic resonance images (MRIs) as compared to computed tomographs (CTs) as a gold standard, (2) could be measured reliably on MRIs, (3) differed between patients with rotator cuff tears (RCTs) and those without evidence of RCTs or glenohumeral osteoarthritis, and (4) differed between patients with rotator cuff repairs (RCRs) that healed and those that did not.

METHODS

This is a retrospective comparative study. We measured coronal, axial, and sagittal acromial tilt; acromial width, acromial anterior and posterior coverage, and glenoid version and inclination on MRI corrected into the plane of the glenoid. We determined accuracy by comparison with CT via intraclass correlation coefficients (ICCs). To determine reliability, these same measurements were made on MRI by 2 observers and ICCs calculated. We compared these measurements between patients with a full-thickness RCT and patients aged >50 years without evidence of an RCT or glenohumeral osteoarthritis. We then compared these measurements between those patients with healed RCRs and those with a retorn rotator cuff on MRI. In this portion, we only included patients with both a preoperative MRI and a postoperative MRI at least 1 year from RCR. Only those patients without tendon defects on postoperative MRIs were considered to be healed. In these patients, we also radiographically measured the critical shoulder angle.

RESULTS

In a validation cohort of 30 patients with MRI and CT, all ICCs were greater than 0.86. In these patients, the inter-rater ICCs of the MRI measurements were >0.53. In our RCT group of 110 patients, there was greater acromial width [mean difference (95% confidence interval) = 0.1 (0, 0.2) mm, P = .012] and significantly less sagittal acromial tilt [9° (5°-12°), P < .001] than in our comparison group of 107 patients. A total of 110 RCRs were included. Postoperative MRI scans were obtained at a mean follow-up of 24.2 ± 15.8 months, showing 84 patients (76%) had healed RCRs. Aside from acromial width, which was 0.2 mm different and thus did not have clinical significance, there was no association between healing and any of the measured morphologic characteristics. Patients with healed repairs had significantly smaller tears in terms of both width (P < .001) and retraction (P < .001).

CONCLUSION

Although the acromion is wider in RCTs, the difference of 0.1 mm likely has no clinical significance. The acromion is more steeply sloped from posteroinferior to anterosuperior in those with RCTs. These findings call into question subacromial impingement due to native acromial morphology as a cause of rotator cuff tearing. Acromial morphology, critical shoulder angle, and glenoid inclination were not associated with healing after RCR. This study does not support lateral acromioplasty.

Relationship Between Acromial Anatomy and Rotator Cuff Tears in Saudi Arabian Population

Objectives

We investigated the relationship between acromial shape, classified as Type I-IV by magnetic resonance imaging, and the occurrence and characteristics of rotator cuff tears (RCTs).

Methods

This retrospective cohort study included 89 patients aged 25 - 60 years who underwent RCT surgeries in the Orthopedic Department at King Abdulaziz University Hospital (KAUH) from January 2014 to April 2019. We collected imaging findings from the KAUH record system, which were then entered into a Google form (Google, Inc., Mountain View, CA) and exported to Microsoft Excel 2016 (Microsoft^® Corp., Redmond, WA). Correlations between variables were assessed using Chi-squared tests.

Results

The supraspinatus muscle in both men and women was most commonly affected by RCTs, accounting for 73.6% of all tears. Subscapularis was the next most commonly injured muscle of the rotator cuff (15.1%), followed by the infraspinatus muscle (11.3%). The majority of supraspinatus, infraspinatus, and subscapularis tears (69.2%, 66.7%, and 56.3%, respectively) were associated with flat acromia. In all cases, tears in association with flat acromia were more prevalent among women (supraspinatus: 51.3% in women, 17.9% in men, p = 0.030; infraspinatus: 50% in women, 16.7% in men, p = 0.292; subscapularis: 43.8% in women, 12.5% in men, p = 0.054).

Conclusions

No correlation exists between acromial shape and sex, regardless of the specific muscle injured. However, supraspinatus injury, acromial shape, and sex are significantly related; right-side partial tear injuries occur more frequently among women aged ≥ 50 years with flat acromia than other RCTs.

Anatomical variations of the acromial and coracoid process: clinical relevance

PURPOSE

The acromial and coracoid process morphology is of clinical relevance due to associations with functional limitations and shoulder pathology. Our objective was to describe the anatomical characteristics of the acromial and coracoid process using computed tomography (CT).

METHODS

Descriptive, observational, transversal and retrospective study. A total of 155 CT of patients without shoulder pathology, of both genders, and indistinct age were evaluated and grouped by age: Group 1 < 25 years; group 2 25-40 years; group 3 > 40 years. The following parameters were evaluated: Acromial type (AcT), vertical coracoid distance (VCD), acromial tilt (AT), acromial projection (AP), critical shoulder angle (CSA), type of the subcoracoid outlet (TSO), and the area of the subcoracoid outlet (ASO).

RESULTS

Statistically significant differences were found between men and women for VCD (14.44 ± 4.79 vs. 11.76 ± 4.00 mm; p < 0.001) and AP (3.66 ± 4.71 vs. 1.62 ± 4.99 mm; p < 0.05) as well as between age groups 1 and 3 for AT (35.08 ± 11.53 vs. 28.41 ± 6.60; p < 0.05) and ASO (398.99 ± 153.91 vs. 255.56 ± 124.58 mm²; p < 0.001). An unexpected high ASO variation was identified with 11% of S-shaped acromion and 1.3% clock-shaped TSO.

CONCLUSION

The age group between 25-40 years had the most uniform distribution of data. There is a high morphological variability present in an asymptomatic population, which should be considered in the clinical assessment such as shoulder impingement syndrome.

Role of shoulder gradient in the pathogenesis of rotator cuff tears

BACKGROUND

Shoulder gradient has been associated with shoulder pathologies such as shoulder impingement syndrome.

AIM

To investigate if there is an association between shoulder gradient and incidence of rotator cuff tear (RCT).

METHODS

A total of 61 patients with a confirmed diagnosis of RCT were included in this retrospective study. The anteroposterior radiograph of the shoulder was used to measure shoulder gradient in adduction and neutral rotation positions. The pain level was assessed with the visual analog scale for pain.

RESULTS

The mean age of the patients was 55.7 ± 12.3 years. The mean visual analog scale of the patients was 4.1 ± 1.2. The mean shoulder gradient was 14.11º ± 2.65º for the affected shoulder and 15.8º ± 2.2º for the unaffected shoulders. This difference was not statistically significant (P = 0.41). A difference of 1.15º ± 1.82º was found between the injured and non-injured shoulder. No significant association was found between the gradient difference of the shoulder and demographic and clinical characteristics of the patients.

CONCLUSION

Shoulder gradient is not associated with the pathology of RCT. Yet, future studies with more standardization and a larger sample size are needed to investigate the role of shoulder gradient in RCT pathogenesis further.

The acromion in supraspinatus outlet and Rockwood caudal tilt views from three-dimensional computed tomography scan of the shoulder

BACKGROUND

A hooked acromion on an outlet view and a keeled acromion on Rockwood tilt radiographs are associated with rotator cuff tears. The identification of the acromial morphology may be helpful for acromioplasty planning with regarding the acromial types.

METHODS

Descriptive Laboratory Study. Three-dimensional computed tomography scans models of 108 shoulders in 91 patients with; (1) Normal shoulders, (2) Shoulders with osteoarthritis, and (3) Irreparable rotator cuff tears; were created and adjusted manually to provide the proper supraspinatus outlet and Rockwood views. The acromial morphology/spurs were analyzed, classified and tested for reliability.

RESULTS

The intra-observer reliability of supraspinatus outlet view had a weak-to-strong agreement [0.828 (95%CI: 0.716-0.945, p-value<0.001), and 0.475 (95%CI: 0.288-0.672, p-value<0.001 from 2 evaluators]. The inter-rater of the supraspinatus outlet view has a minimal-to-moderate agreement [0.782 (95%CI: 0.662-0.907, p-value<0.001), and 0.344 (95%CI: 0.157-0.539, p-value<0.001) in the first and second readings]. The intra-observer reliability of the Rockwood view has a moderate-to-almost-perfect agreement [0.752 (95%CI: 0.652-0.860, p-value<0.001), and 0.903 (95%CI: 0.833-0.974, p-value<0.001) from 2 evaluators]. The inter-observer reliability of the Rockwood view has a moderate-to-strong agreement [0.854 (95%CI: 0.777-0.936, p-value<0.001), and 0.737 (95%CI: 0.634-0.847, p-value<0.001) in the first and second readings].

CONCLUSION

The classification of acromion morphology under Three-dimensional computed tomography in the supraspinatus outlet view has poor reliability. The Rockwood caudal tilt view model results in moderate-to-almost-perfect reliability that can be developed to the plain radiographic classification to determine the need for acromioplasty in rotator cuff surgery.

Surgery for rotator cuff tears

BACKGROUND

This review is one in a series of Cochrane Reviews of interventions for shoulder disorders.

OBJECTIVES

To synthesise the available evidence regarding the benefits and harms of rotator cuff repair with or without subacromial decompression in the treatment of rotator cuff tears of the shoulder.

SEARCH METHODS

We searched the CENTRAL, MEDLINE, Embase, Clinicaltrials.gov and WHO ICRTP registry unrestricted by date or language until 8 January 2019.

SELECTION CRITERIA

Randomised controlled trials (RCTs) including adults with full-thickness rotator cuff tears and assessing the effect of rotator cuff repair compared to placebo, no treatment, or any other treatment were included. As there were no trials comparing surgery with placebo, the primary comparison was rotator cuff repair with or without subacromial decompression versus non-operative treatment (exercises with or without glucocorticoid injection). Other comparisons were rotator cuff repair and acromioplasty versus rotator cuff repair alone, and rotator cuff repair and subacromial decompression versus subacromial decompression alone. Major outcomes were mean pain, shoulder function, quality of life, participant-rated global assessment of treatment success, adverse events and serious adverse events. The primary endpoint for this review was one year.

DATA COLLECTION AND ANALYSIS

We used standard methodologic procedures expected by Cochrane.

MAIN RESULTS

We included nine trials with 1007 participants. Three trials compared rotator cuff repair with subacromial decompression followed by exercises with exercise alone. These trials included 339 participants with full-thickness rotator cuff tears diagnosed with magnetic resonance imaging (MRI) or ultrasound examination. One of the three trials also provided up to three glucocorticoid injections in the exercise group. All surgery groups received tendon repair with subacromial decompression and the postoperative exercises were similar to the exercises provided for the non-operative groups. Five trials (526 participants) compared repair with acromioplasty versus repair alone; and one trial (142 participants) compared repair with subacromial decompression versus subacromial decompression alone. The mean age of trial participants ranged between 56 and 68 years, and females comprised 29% to 56% of the participants. Symptom duration varied from a mean of 10 months up to 28 months. Two trials excluded tears with traumatic onset of symptoms. One trial defined a minimum duration of symptoms of six months and required a trial of conservative therapy before inclusion. The trials included mainly repairable full-thickness supraspinatus tears, six trials specifically excluded tears involving the subscapularis tendon. All trials were at risk of bias for several criteria, most notably due to lack of participant and personnel blinding, but also for other reasons such as unclearly reported methods of random sequence generation or allocation concealment (six trials), incomplete outcome data (three trials), selective reporting (six trials), and other biases (six trials). Our main comparison was subacromial decompression versus non-operative treatment and results are reported for the 12 month follow up. At one year, moderate-certainty evidence (downgraded for bias) from 3 trials with 258 participants indicates that surgery probably provides little or no improvement in pain; mean pain (range 0 to 10, higher scores indicate more pain) was 1.6 points with non-operative treatment and 0.87 points better (0.43 better to 1.30 better) with surgery.. Mean function (zero to 100, higher score indicating better outcome) was 72 points with non-operative treatment and 6 points better (2.43 better to 9.54 better) with surgery (3 trials; 269 participants), low-certainty evidence (downgraded for bias and imprecision). Participant-rated global success rate was 873/1000 after non-operative treatment and 943/1000 after surgery corresponding to (risk ratio (RR) 1.08, 95% confidence interval (CI) 0.96 to 1.22; low-certainty evidence (downgraded for bias and imprecision). Health-related quality of life was 57.5 points (SF-36 mental component score, 0 to 100, higher score indicating better quality of life) with non-operative treatment and 1.3 points worse (4.5 worse to 1.9 better) with surgery (1 trial; 103 participants), low-certainty evidence (downgraded for bias and imprecision). We were unable to estimate the risk of adverse events and serious adverse events as only one event was reported across the trials (very low-certainty evidence; downgraded once due to bias and twice due to very serious imprecision).

AUTHORS' CONCLUSIONS

At the moment, we are uncertain whether rotator cuff repair surgery provides clinically meaningful benefits to people with symptomatic tears; it may provide little or no clinically important benefits with respect to pain, function, overall quality of life or participant-rated global assessment of treatment success when compared with non-operative treatment. Surgery may not improve shoulder pain or function compared with exercises, with or without glucocorticoid injections. The trials included have methodology concerns and none included a placebo control. They included participants with mostly small degenerative tears involving the supraspinatus tendon and the conclusions of this review may not be applicable to traumatic tears, large tears involving the subscapularis tendon or young people. Furthermore, the trials did not assess if surgery could prevent arthritic changes in long-term follow-up. Further well-designed trials in this area that include a placebo-surgery control group and long follow-up are needed to further increase certainty about the effects of surgery for rotator cuff tears.