Higher Critical Shoulder Angle and Acromion Index Are Associated With Increased Retear Risk After Isolated Supraspinatus Tendon Repair at Short-Term Follow Up

Deep learning algorithms enable MRI-based scapular morphology analysis with values comparable to CT-based assessments

Scapular morphological attributes show promise as prognostic indicators of retear following rotator cuff repair. Current evaluation techniques using single-slice magnetic-resonance imaging (MRI) are, however, prone to error, while more accurate computed tomography (CT)-based three-dimensional techniques, are limited by cost and radiation exposure. In this study we propose deep learning-based methods that enable automatic scapular morphological analysis from diagnostic MRI despite the anisotropic resolution and reduced field of view, compared to CT. A deep learning-based segmentation network was trained with paired CT derived scapula segmentations. An algorithm to fuse multi-plane segmentations was developed to generated high-resolution 3D models of the scapula on which morphological landmark- and axes were predicted using a second deep learning network for morphological analysis. Using the proposed methods, the critical shoulder angle, glenoid inclination and version were measured from MRI with accuracies of -1.3 ± 1.7 degrees, 1.3 ± 2.1 degree, and - 1.4 ± 3.4 degrees respectively, compared to CT. Inter-class correlation between MRI and CT derived metrics were substantial for the glenoid version and almost perfect for the other metrics. This study demonstrates how deep learning can overcome reduced resolution, bone border contrast and field of view, to enable 3D scapular morphology analysis on MRI.

Investigating the Role of Symptom Duration and Critical Shoulder Angle in Predicting Acromiohumeral Interval Reversibility in Patients With Massive Rotator Cuff Tears

Background

Acromiohumeral interval (AHI) reversibility is used to evaluate whether superior humeral migration is fixed or flexible in patients with massive rotator cuff tears (MRCTs). AHI reversibility is measured as the difference in the AHI observed between standard and stress radiography. However, factors affecting AHI reversibility have not been studied in the existing literature.

Purpose

To investigate potential factors affecting AHI reversibility in patients with MRCTs.

Study Design

Case-control study; Level of evidence, 3.

Methods

A retrospective analysis was conducted on 58 patients with MRCTs, who had undergone magnetic resonance imaging, computed tomography, and stress radiography of the same shoulder. Potential factors affecting AHI reversibility were evaluated by stepwise regression analysis.

Results

A total of 58 patients (26 male, 32 female) were included in this study. The mean age of the patients was 66.4 ± 8.3 years. There were 33 patients classified as having a reversible AHI and 25 patients classified as having an irreversible AHI. Age, time from symptom onset, anteroposterior tear size, critical shoulder angle (CSA), acromial index, and subscapularis Goutallier grade were associated with AHI reversibility in univariate analysis. Multivariate linear regression analysis showed that a longer time from symptom onset and a bigger CSA were significantly associated with lower AHI reversibility. No significant association was found between AHI reversibility and sex; body mass index; activity level; tear retraction; biceps condition; deltoid cross-sectional area; and Goutallier grade of the supraspinatus, infraspinatus, and teres minor muscles. The cutoff values to predict AHI reversibility for time from symptom onset and CSA were found to be 5.5 years and 38°, respectively.

Conclusion

Time from symptom onset (>5.5 years) and CSA (>38°) were significant independent factors of AHI reversibility. These factors should be considered for the decision-making process in patients with MRCTs.

Disparities in Rotator Cuff Tear Progression Definitions and Rates: A Systematic Review

Background

While rotator cuff tears are prevalent in the general population, the natural history of this disease is unclear. Understanding rotator cuff tear progression is crucial for refining surgical indications and evaluating the necessity of early interventions. This study presents an in-depth analysis of the existing literature on the definitions and progression rates of rotator cuff tears, aiming to enhance clinical decision making and patient outcomes.

Methods

A systematic literature search was conducted based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, using Medline (PubMed), Embase (Elsevier), and Web of Science databases on January 12, 2023. Articles were identified as relevant to the natural history and progression of asymptomatic and symptomatic partial-thickness (PT) and full-thickness (FT) rotator cuff tears. Those written in English reporting rotator cuff progression rates of tears in adults, based on magnetic resonance imaging (MRI) or ultrasound, were included. After reviewing the articles, the data on the rates of tear progression and associated risk factors were extracted, compiled, and analyzed. The risk of bias was determined using the Newcastle-Ottawa Scale.

Results

Twenty-one articles met the inclusion criteria, with 1,831 tears included. The progression rate for all partial thickness tears was 26.7% ± 12.8% at an average follow-up of 2.2 ± 0.9 years, with 5 definitions for tear progression. For FT tears, the progression rate was 54.9% ± 18.6% at a follow-up time of 3.0 ± 2.0 years, with 8 definitions for tear enlargement. A significant difference (p < 0.0001) was found between the progression rates of PT and FT tears. Patients who were initially asymptomatic and became symptomatic had higher progression rates (33%-63%) than those who remained asymptomatic (4%-38%).

Conclusion

Further research would benefit by identifying a clinically relevant and standardized definition of rotator cuff tear progression, to describe the natural history of rotator cuff disease, making results more comparable and optimizing treatment planning.

Level of Evidence

Level II. See Instructions for Authors for a complete description of levels of evidence.

Fatty Infiltration, Tear Size, and Retraction Size Are Significant Risk Factors for Retear After Arthroscopic Rotator Cuff Repair: A Systematic Review

PURPOSE

To assess the consistency and quality of risk factor reporting for rotator cuff repair (RCR) retear and identify risk factors most frequently associated with retear.

METHODS

A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Of the initial 3,158 studies, a total of 31 met the following inclusion criteria: (1) clinical studies regarding RCR failure, (2) arthroscopic procedures involving RCR, (3) reporting of clinical outcomes, (4) publication within the past 5 years, and (5) studies investigating preoperative risk factors for retear. After full-text review, 18 risk factors were analyzed.

RESULTS

The most consistently significant risk factors were acromiohumeral distance (80%), critical shoulder angle (67%), tear size (63%), anterior-posterior dimension (60%), fatty infiltration (FI) (58%), and retraction size (56%). FI was analyzed using different methods among studies, with 63% finding significant results and 50% of all studies performing ordinal analysis. Tear size was inconsistently analyzed quantitatively or qualitatively, with 58% of studies finding significant results and 63% of all studies performing quantitative analysis. Risk factors consistently found to be nonsignificant included age, sex, diabetes mellitus, symptom duration, hand dominance, repair technique, smoking, and body mass index.

CONCLUSIONS

Tear size, FI, and retraction size were found to be significant risk factors in most of the included studies evaluating rotator cuff retear. Risk factors less likely reported as predictive included repair technique, age, sex, diabetes mellitus, symptom duration, hand dominance, repair technique, smoking, and body mass index. Risk factors that require further investigation include critical shoulder angle, acromiohumeral distance, and anterior-posterior tear dimension.

LEVEL OF EVIDENCE

Level III, systematic review of Level III-IV studies.

Lower Reoperation Rate and Superior Patient-Reported Outcome Following Arthroscopic Rotator Cuff Repair With Concomitant Acromioplasty: An Updated Systematic Review of Randomized Controlled Trials

PURPOSE

To systematically assess the postoperative outcomes in patients undergoing arthroscopic rotator cuff repairs with or without concomitant acromioplasty through a rigorous systematic review of randomized controlled trials (RCTs).

METHODS

This systematic review, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, aimed to identify RCTs comparing clinical outcomes of patients with full-thickness rotator cuff tears undergoing arthroscopic rotator cuff repair with acromioplasty versus those without at a minimum 12-month follow-up. Databases searched included PubMed, Web of Science, Embase, and the Cochrane Library. The risk of bias in the included studies was assessed using the revised Cochrane Risk of Bias 2. Meta-analysis was conducted for outcomes with at least 3 studies reporting, with pooled effect estimates calculated using either fixed-effect or random-effects models based on heterogeneity levels. Results were presented as the weighted mean difference or odds ratio with 95% confidence intervals (CIs). For outcomes with fewer than 3 studies reporting, a Fisher exact test was conducted, with continuity correction applied if necessary. Primary outcomes included rates of retear and reoperation, whereas secondary outcomes included improvement in American Shoulder and Elbow Surgeons (ASES) score, range of motion (ROM), and complication rate.

RESULTS

Five high-quality RCTs, with low bias risk, involving 409 patients, revealed demographics of 58.4% males, mean age of 58.4 years, and the following acromion types: 12.2% type I, 70.7% type II, and 17.1% type III. Mean follow-up was 52.2 months. Retear (12.5% vs 16.1%, P = .536) and complication rates (odds ratio, 3.11; 95% CI, 0.31-30.73; P = .33) were comparable between the 2 groups. However, reoperation rate (5.3% vs 15.9%, P < .001) and improvement in ASES score (weighted mean difference, 3.99; 95% CI, 1.00-6.99; P = .009) favored the acromioplasty group. Both groups showed significant improvements in ROM, but insufficient data prevented a comparison.

CONCLUSIONS

Compared with arthroscopic rotator cuff repair alone, arthroscopic rotator cuff repair with acromioplasty demonstrated similar rates of retear and complications but had a significantly lower reoperation rate and superior improvement in ASES score. The available data were insufficient to draw a definitive conclusion regarding ROM. This conclusion is fragile due to a limited sample size.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and II studies.

Impact of critical shoulder angle in shoulder pathology: a current concepts review

Background

This review aims to describe the origin and development of critical shoulder angle (CSA) and its correlation with different shoulder pathologies. Current literature is inconclusive in characterizing the role of CSA in predicting pathology and surgical outcomes.

Methods

A literature search of both historical and more contemporary research articles on CSA was conducted to compare data points on the impact of CSA on shoulder pathology and postoperative clinical outcomes. This compilation of studies ranges from retrospective reviews to case series as well as cadaveric imaging studies.

Results

The CSA is a reliable radiographic measure in predicting shoulder pathology in correctly oriented radiographs. Surgically modifying the CSA with arthroscopic lateral acromioplasty and results has largely shown improved recovery of strength postoperatively as with no increase in postsurgical complication rates. However, it remains unclear whether surgical alteration of CSA has a role in preventing clinical failure after arthroscopic procedures such as acromioplasty and rotator cuff repair as well as following shoulder arthroplasty.

Discussion

Stronger conclusions regarding the prognostic utility of CSA are limited by the fact that most studies evaluating CSA are smaller retrospective cohorts. Moving forward, randomized controlled trials being conducted may offer greater insight as to how CSA can improve patient-reported outcomes postoperatively.

The Association between SLAP Lesions and Critical Shoulder Angle and Glenoid Depth

PURPOSE OF THE STUDY

The critical shoulder angle (CSA) is formed by the combination of glenoid inclination and acromial index and has been shown related to rotator cuff tears and glenohumeral osteoarthritis. SLAP lesions today have an important place among bicipitolabral pathologies that cause intensive shoulder pain. We aimed to investigate the relationship between CSA and glenoid depth and SLAP lesions.

MATERIAL AND METHODS

Between March 2017 and January 2022, 279 consecutive shoulder arthroscopy patients' MRI images were retrospectively examined. After the exclusion criteria, 191 patients were eligible. Patients with SLAP lesions (n=37) were assembled as the study group (Group 1), and patients with intact superior labrum (n=154) were named as the control group (Group 2). Critical shoulder angle (CSA) and glenoid depth measurements were performed using the preoperative MRI images.

RESULTS

A total of 191 patients, of whom 84 were male (44%) were included. The mean age was 49.9±14.96 (range 18-79). There was a statistically signifi cant difference between the SLAP group (Group 1) and the control group (Group 2) in terms of CSA (p=0.032). The mean CSA was 31.66°±3.51° in Group 1 and 33.57° ±5.01° in Group 2. The cut-off value for CSA in patients with SLAP lesions was calculated as 32.85° and the area under the curve was 0.61, therefore a satisfactory association was observed between the groups. The mean glenoid depth was 4.32 ±1.25 mm in Group 1, and 4.39 ±0.32 mm in Group 2. There was no statistically signifi cant difference between the groups in terms of glenoid depth (p=0.136) and also no association between the glenoid depth and SLAP lesions was observed (cut-off=4.45 mm, AUC=0.32).

CONCLUSIONS

Low CSA is associated with SLAP lesions, just as in glenohumeral osteoarthritis. Further prospective clinical studies are needed to enlighten the predisposing effect of CSA to SLAP lesions and the success of superior labral repairs.

LEVEL OF EVIDENCE

Retrospective comparative study, Level III.

MRI is a Reliable Method for Measurement of Critical Shoulder Angle and Acromial Index

Objective  The objectives of this study are to compare absolute values of acromial index (AI) and critical shoulder angle (CSA) obtained in both radiographs and magnetic resonance image (MRI) of the shoulder; and to compare the interobserver and intra-observer agreement for AI and CSA values measured in these image modalities. Methods  Patients who had medical indication of investigating shoulders conditions through radiographs and MRI were included. Images were taken to two fellowship-trained shoulder surgeons, which conducted measurements of AI and CSA in radiographs and in MRI. Twelve weeks after the first evaluation, a second evaluation was conducted. Inter- and intra-observer reliability was presented as an Intraclass Correlation Coefficient (ICC) and agreement was classified according to Landis & Koch criteria. The differences between two measurements were evaluated using Bland-Altman plots. Results  134 shoulders in 124 subjects were included. Mean intra-observer ICC for CSA in X-rays and in MRI were 0.936 and 0.940, respectively; for AI, 0.908 and 0.022. Mean inter-observer ICC for CSA were 0.892 and 0.752 in X-rays and MRI respectively; for AI, ICC values were 0.849 and 0.685. All individual analysis reached statistical power ( p  < 0.001). Mean difference for AI values measured in X-rays and in MRI was 0.01 and 0.03 for observers 1 and 2, respectively. Mean difference for CSA values obtained in X-rays and MRI was 0.16 and 0.58 for observers 1 and 2, respectively. Conclusion  Both MRI and X-rays provided high intra- and interobserver agreement for measurement of AI and CSA. Absolute values found for AI and CSA were highly correlated in both image modalities. These findings suggest that MRI is a suitable method to measure AI and CSA. Level of Evidence II , Diagnostic Study.

Prediction of Retear After Arthroscopic Rotator Cuff Repair Based on Intraoperative Arthroscopic Images Using Deep Learning

BACKGROUND

It is challenging to predict retear after arthroscopic rotator cuff repair (ARCR). The usefulness of arthroscopic intraoperative images as predictors of the ARCR prognosis has not been analyzed.

PURPOSE

To evaluate the usefulness of arthroscopic images for the prediction of retear after ARCR using deep learning (DL) algorithms.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 2.

METHODS

In total, 1394 arthroscopic intraoperative images were retrospectively obtained from 580 patients. Repaired tendon integrity was evaluated using magnetic resonance imaging performed within 2 years after surgery. Images obtained immediately after ARCR were included. We used 3 DL architectures to predict retear based on arthroscopic images. Three pretrained DL algorithms (VGG16, DenseNet, and Xception) were used for transfer learning. Training and test sets were split into 8:2. Threefold stratified validation was used to fine-tune the hyperparameters using the training data set. The validation results of each fold were evaluated. The performance of each model in the test set was evaluated in terms of accuracy, area under the receiver operating characteristic curve (AUC), F1-score, sensitivity, and specificity.

RESULTS

In total, 1138 and 256 arthroscopic images were obtained from 514 patients and 66 patients in the nonretear and retear groups, respectively. The mean validation accuracy of each model was 83% for VGG16, 89% for Xception, and 91% for DenseNet. The accuracy for the test set was 76% for VGG16, 87% for Xception, and 91% for DenseNet. The AUC was highest for DenseNet (0.92); it was 0.83 for VGG16 and 0.91 for Xception. For the test set, the specificity and sensitivity were 0.93 and 0.84 for DenseNet, 0.89 and 0.84 for Xception, and 0.70 and 0.80 for VGG16, respectively.

CONCLUSION

The application of DL algorithms to intraoperative arthroscopic images has demonstrated a high level of accuracy in predicting retear occurrences.

High Acromial Slope and Low Acromiohumeral Distance Increase the Risk of Retear of the Supraspinatus Tendon After Repair

BACKGROUND

Retearing of the supraspinatus (SSP) tendon after repair is relatively common, but its cause is rarely clear. Although the role of acromion morphology and glenoid orientation in the pathogenesis of primary SSP tendon tears have frequently been analyzed, their association with the risk of rerupture of a repaired SSP tendon is poorly understood.

QUESTIONS/PURPOSES

(1) Is acromial morphology associated with the risk of retear after SSP tendon repair? (2) Is there an association between inclination and version of the glenoid and the odds for retear of the SSP tendon after repair? (3) Are there differences in outcome scores between patients who had intact cuff repairs and those who had retears?

METHODS

Between August 2012 and December 2015, we treated 92 patients for SSP tendon tears; all of these patients were considered for inclusion in the present study. We considered patients with complete tear of the SSP that was reconstructed with a double-row repair and a minimum follow-up of 2 years as potentially eligible. Based on these criteria, 28% (26 of 92) were excluded because they had a partial rupture and did not receive a double-row reconstruction. A further 9% (eight of 92) were excluded because of missing planes or slices (such as sagittal, axial, or frontal) on MRI, and another 3% (three of 92) were lost before the minimum study follow-up interval or had incomplete datasets, leaving 60% (55 of 92) for inclusion in the present analysis. All included patients had a minimum follow-up of 2 years; follow-up with MRI occurred at a mean duration of 2.3 ± 0.4 years postoperatively. All patients were asked to complete the Western Ontario Rotator Cuff Index and Oxford Shoulder Scores, and they underwent MRI of the operated-on shoulder. Preoperative true AP radiographs and MR images of the affected shoulders were retrospectively assessed by measuring the acromiohumeral interval, critical shoulder angle, acromial slope, acromial tilt, acromial index, lateral acromial angle, and glenoid version and inclination. The patients also underwent acromioplasty, in which the underface of the acromion was flattened. To rule out any change in the above parameters because of acromioplasty, these parameters were compared using preoperative and postoperative MR images and showed no difference. In addition, the tendon integrity and quality on postoperative MRI were analyzed independently of one another by the same two observers using the Sugaya and Castricini classifications, accounting for atrophy and fatty degeneration of the SSP muscle. To assess interobserver reliability, the two observers took measurements independently from each other. They were orthopaedic residents who completed a training session before taking the measurements. All measurements had excellent intrarater (Cronbach alpha 0.996 [95% confidence interval (CI) 0.99 to 1.00; p > 0.01) and interrater (interrater correlation coefficient 0.975 [95% CI 0.97 to 0.98]; p > 0.01) reliabilities. To answer the study's first question, SSP integrity on postoperative MRI was compared with acromial morphologic parameters measured on preoperative AP radiographs and MR images. To answer the second question, the postoperative integrity and quality of the SSP tendon were correlated with glenoid inclination and glenoid version. To answer our third question, we compared outcome scores between patients with intact SSP tendons and those with reruptured SSP tendons. To investigate any correlation among the acromial morphology, glenoid orientation, and postoperative outcomes, a binomial logarithmic regression analysis was performed. Receiver operating characteristic curves were used to determine cutoff points for the radiologic parameters that showed a correlation in the binomial regression analysis.

RESULTS

After controlling for potentially confounding variables such as acromioplasty or preoperative fatty infiltration as well as muscle atrophy, the only morphological parameters associated with a higher risk (adjusted odds ratio) of SSP tendon rerupture were the acromiohumeral interval (adjusted OR 0.9 [95% CI 0.9 to 0.99]; p < 0.01) and acromial slope (adjusted OR 1.4 [95% CI 1.1 to 1.8]; p < 0.01). The critical shoulder angle, acromial tilt, acromial index, and lateral acromial angle were not associated with the risk of rerupture. The cutoff values for acromial slope and acromiohumeral interval were 24.5° and 7.4 mm, respectively. Patients with an acromiohumeral interval smaller than 7.4 mm or an acromial slope greater than 24.5° had higher odds (acromiohumeral interval: OR 11 [95% CI 2 to 46]; p = 0.01 and acromial slope: OR 9 [95% CI 2 to 46]; p = 0.04) for rerupture of the SSP. No difference was found between patients with intact SSP tendons and those with reruptured SSP tendons in terms of glenoid inclination (6° ± 4° versus 6° ± 3°, mean difference 0.8° [-1° to 3°]; p < 0.48) and glenoid version (-2° ± 3° versus -3° ± 3°, mean difference 1° [-1° to 3°]; p < 0.30). No difference was found between the intact and reruptured SSP groups regarding clinical outcomes (Western Ontario Rotator Cuff Index: 98 ± 2 versus 97 ± 3, mean difference 0.73 [95% CI -0.30 to 0.31]; p = 0.96; Oxford Shoulder Score: 26 ± 13 versus 23 ± 10, mean difference 2.80 [95% CI -4.12 to 9.72]; p = 0.41).

CONCLUSION

The preoperative acromiohumeral interval and acromial slope are associated with SSP tendon rerupture after repair. Conversely, the critical shoulder angle, acromial tilt, lateral acromial angle, and acromial index had no association with the postoperative outcome. Additionally, glenoid inclination and version were not associated with the rerupture rate after SSP tendon repair. A detailed analysis of the acromiohumeral interval and acromial slope is recommended in clinical practice in patients undergoing SSP tendon repair. Surgeons should consider measuring the acromiohumeral interval and acromial slope preoperatively when performing SSP repair, especially in the context of planned acromioplasties. Future studies should investigate the role of acromioplasty during SSP repair in patients with a pathologic acromial slope and acromiohumeral interval. In this context, it should be determined whether a more-radical acromioplasty could reduce the risk of rerupture of the SSP in these patients.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Editorial Commentary: In Contrast to Chronic, Degenerative Rotator Cuff Tears, the Critical Shoulder Angle in Traumatic Rotator Cuff Tears Can Be Ignored

There are 2 distinct types of rotator cuff tears. The first is a chronic, degenerative tear, which is more common. The second is an acute traumatic tear. (There is also likely a third, hybrid type consisting of an acute-on-chronic tear) Traumatic tears result in acute dysfunction with weakness and loss of range of motion. Traumatic tears are large to massive in size and have higher degrees of subscapularis involvement. If a patient has an acute cuff tear, the surgeon should fix it. The surgeon should not take the time to measure the critical shoulder angle (CSA) or plan an acromioplasty but should just fix the tear-the sooner, the better. The CSA has been emerging as a concept in trying to figure out the pathogenesis and treatment of degenerative tears. But, when it comes to traumatic tears, the CSA can be ignored. It likely does not have a role in the causation or treatment of traumatic rotator cuff tears.

Acute, Traumatic Rotator Cuff Tears Have Smaller Critical Shoulder Angles Than Degenerative Tears

PURPOSE

To determine whether the critical shoulder angle (CSA) in acute, traumatic rotator cuff tears (RCTs) is consistent with the previously described CSA in chronic degenerative RCTs.

METHODS

We performed a multicenter retrospective analysis of 134 patients presenting to 5 surgeons fellowship trained in shoulder and elbow or sports. Preoperative imaging was used to measure the CSA and tear characteristics. Patients were included if they had acute, traumatic full-thickness RCTs documented on advanced imaging and had preoperative Grashey radiographs. Patients were excluded if they had any history of shoulder pain, injury, surgery, or treatment prior to the current episode; were overhead athletes; or had fatty infiltration greater than Goutallier grade 1 on imaging.

RESULTS

The mean CSA was 33.5° (standard deviation, 4.1°), and 60% of tears had a CSA of less than 35°, much below the mean of 38.0° and the threshold of greater than 35° in degenerative RCTs. The mean age was 58 years, and 70% of patients were men. Overall, 60% of tears involved the subscapularis, 49% of tears occurred in patients aged 60 years or older, and 18% of patients sustained a dislocation. Older age (β = 0.316, P = .003) and male sex (β = 5.532, P = .025) were predictive of tear size, and older age (β = 0.229, P = .011) and biceps avulsion (β = 8.822, P = .012) were predictive of tear retraction.

CONCLUSIONS

Acute, traumatic RCTs have CSAs that are 5° smaller than those of degenerative tears, and the majority (60%) have CSAs that are below the threshold consistent with degenerative RCTs. The majority of traumatic tears (60%) involve the subscapularis.

CLINICAL RELEVANCE

The study findings suggest that a traumatic tear is not simply the acute failure of a degenerative tendon and that it represents a distinct pathologic entity. These findings support current practice of treating traumatic RCTs differently than degenerative RCTs.

How much acromial bone should be removed to decrease the critical shoulder angle? A 3D CT acromioplasty planning study

BACKGROUND

A high critical shoulder angle (CSA) is associated with rotator cuff tear (RCT) and retear rate after repair. CSA reduced to less than 33° by acromioplasty is correlated with better clinical results and healing. But up to 24% of patients retain a CSA above 35° after acromioplasty. The objective of the study was to evaluate the use of 3D when planning acromioplasty and measure acromial bone removal volume dimensions.

METHODS

Computed tomography (CT) scans from 45 patients with RCT and CSA ≥ 38° were retrospectively included. A 33° CSA cutting plane was positioned. Acromion was divided into 5 mm slices and acromial bone resection measured on each slice.

RESULTS

Intra- and inter-observer reproducibility measurements were rated strong or very strong. Patients' mean preoperative CSA was 40° (38°, 49° ± 2.3°). Measurements of acromial resection were: anteroposterior length: 32.7 mm (20, 50 ± 7.4); inferior width: 7.6 mm (4.2, 19 ± 2.9); superior width: 4.1 mm (0, 16 ± 3.0); height: 6.1 mm (1.7, 6.7 ± 1.6); and cutting angle: 74° (46, 91 ± 8.0). Maximum width of acromial resection was located 10.6 mm (5, 17.5 ± 0.6) from the acromion's anterior edge and decreased gradually moving posteriorly. Preoperative CSA was linearly correlated with width (P < 0.0001, R = 84%) and length (P = 0.0001, R = 28%) of acromioplasty; the higher the CSA, the greater the width and length.

CONCLUSIONS

3D CT reconstructions are valid for planning a CSA decreasing acromioplasty. To reduce CSA to 33°, acromioplasty must be performed anterolaterally and resection is at least 2 cm long anteroposteriorly. For higher CSAs, acromioplasty may require lateral resection over 1 cm in width and up to 5 cm in length. To decrease the CSA efficiently, acromioplasty must be adapted to patient anatomy and 3D planning could be considered.

LEVEL OF EVIDENCE

IV.

Anterolateral Acromioplasty Does Not Change the Critical Shoulder Angle and Acromion Index in a Clinically Relevant Amount

PURPOSE

Assessment on whether radiographic parameters of the acromion measured in radiographs change significantly after anterolateral acromioplasty.

METHODS

This retrospective study included patients that underwent an arthroscopic anterolateral acromioplasty between January 2014 and September 2020. n = 435 subjects with high-quality preoperative and postoperative radiographs according to Suter-Henninger criteria were included in the final assessment. All measurements were independently performed by the first and second author in a blinded fashion using dicomPACS software: acromion index (AI), critical shoulder angle (CSA), lateral acromial angle (LAA), beta angle, acromio-humeral distance (AHD), Aoki angle, frontal supraspinatus outlet angle (FSOW), and acromion type, according to Bigliani. SPSS software was used for statistical analysis.

RESULTS

The beta angle and the CSA did not significantly change after operation (alpha power 0.32 and 0.11, respectively). In a subgroup analysis of patients with a pathological CSA >35° (n = 194), the CSA changed from 38.62 (range: 35.08-47.52, SD 2.83) to 38.04 (range: 29.18-48.12, SD 3.77) postoperatively (P = .028) (Fig 8). All other parameters changed significantly after operation (AI, AHD, FSOW, and Aoki; P = .001, LAA; P = .039) (Fig. 9). The interobserver and intraobserver reliability was good to excellent in the majority of measured values. Mean patient age was 59.2 years (range: 18.1-87.1; SD 11.3), mean height was 1.73 meters (range: 1,50-1.98, SD 0.09), mean weight was 80.2 kg (range: 37.0-133.0, SD 16.68), and mean body mass index was 26.6 (range: 0.0-46.1, SD 4.73).

CONCLUSION

Anterolateral acromioplasty producing a flat acromion undersurface did not result in a significant change of the CSA in the study population. Pathological preoperative CSA values of >35° were significantly reduced but not to normal values, but only by a small amount that puts the clinical relevance into question.

LEVEL OF EVIDENCE

IV, diagnostic study, case series.

Editorial Commentary: Classic Arthroscopic Anterolateral Acromioplasty Does Not Translate to Clinically Meaningful Differences in Lateral Acromial Overcoverage

Despite its time-honored tradition, the classic Neer acromioplasty has come under increased scrutiny in the recent literature, particularly when performed in the absence of rotator cuff repair. The American Medical Association Current Procedural Terminology Committee has transitioned the acromioplasty procedure, and definition of the related Current Procedural Terminology code 29827, to a procedure that is "added-on" to shoulder arthroscopy. Several authors have sought to investigate the true value of arthroscopic subacromial decompression for extrinsic sources of impingement. Common indications for acromioplasty include bursal-sided tears, prominent type III hooked acromial morphology, calcified coracoacromial ligament, and severe rotator cuff tendinopathy. However, the classic arthroscopic acromioplasty may not meaningfully address lateral outlet impingement and acromial overcoverage, as measured by an elevated critical shoulder angle or acromial index, thereby leading to persistent abduction impingement and mechanical abrasion. In these cases, lateral acromial resection of up 5 to 10 mm may be preferentially considered to decrease the pathologic critical shoulder angle (>35°) and reduce the risk of primary or secondary rotator cuff tendon failure.

Does the critical shoulder angle influence retear and functional outcome after arthroscopic rotator cuff repair? A systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis aimed to evaluate the correlation between increased critical shoulder angle (CSA) and higher retear rates and functional outcomes after arthroscopic rotator cuff repair (ARCR).

METHODS

PubMed, Embase, Web of Science, and Cochrane Library databases published before January 2022 were comprehensively searched. Two reviewers independently reviewed the titles and abstracts using the specified criteria. Studies were included if the authors clearly described the correlation between the CSA and rotator cuff repair. Data on patient characteristics, mean CSA, retear rate, and the functional score was pooled from the selected articles. A meta-analysis was performed using Review Manager (RevMan) 5.4.1 software, 2020 (Cochrane Collaboration, Copenhagen, Denmark).

RESULTS

Eleven articles involving 1449 patients from 7 countries were included. The ages of the patients ranged from 45 to 75 years. The follow-up period ranged from 6 to 96 months. The mean CSA was greater in the retear group than in the non-retear group after ARCR (mean difference 2.73°; 95% confidence interval [CI] 0.69-4.77) (p = 0.009). Three studies evaluated the association between increased CSA and the postoperative retear rate. All three studies showed a higher postoperative retear rate in patients with an increased CSA (odds ratio 5.35; 95% CI 2.02-14.15; p = 0.0007). No association was found between CSA and Constant-Murley (Constant), the University of California at Los Angeles (UCLA), or Visual Analog Scale (VAS) scores during the follow-up period of 24-96 months (p > 0.05).

CONCLUSIONS

This systematic review and meta-analysis showed that CSA correlates highly with rotator cuff retear after ARCR. In addition, the postoperative retear rate of the rotator cuff increased with increased CSA. CSA appeared to not affect worse functional outcomes in patients after ARCR.

Radiographs Are Comparable With 3-Dimensional Computed Tomography-Based Models as a Modality for the Preoperative Planning of the Arthroscopic Lateral Acromioplasty: A Retrospective Comparative Study

Purpose

To compare plain radiographs with 3-dimensional (3D) computed tomography (CT) data for preoperative planning of arthroscopic lateral acromioplasty (ALA) for patients in whom ALA was performed along with arthroscopic rotator cuff repair (ARCR).

Methods

Patients older than 25 years old who underwent ALA along with ARCR in our institution between October 2019 and February 2021 were included in this study. Preoperative ALA simulations were performed on plain radiographs and 3D models based on CT data. The critical shoulder angle (CSA) was compared between simulations based on radiographs and those based on 3D models. The ALA procedure was performed using the 3D model simulation, along with ARCR. The CSA after surgery was investigated using radiographs.

Results

We evaluated 11 shoulders in 10 patients. There was no significant difference between the mean preoperative CSA on radiographs and 3D models (38.0° ± 2.6° vs 38.6° ± 1.8°, respectively; P = .55). The mean CSA after 4-mm ALA simulation using radiographs was not significantly different to that using 3D models (34.1° ± 2.6° vs 34.3° ± 2.5°, respectively; P = .84). Four cases (36.4%) required 8-mm ALA to reduce the CSA to <35° on radiographic analysis, and 2 (18.2%) required 8-mm ALA on 3D model analysis. The mean CSA on postoperative radiographs was significantly smaller than that on preoperative radiographs (32.1° ± 2.7° vs 38.0° ± 2.6°, respectively; P < .01).

Conclusions

There was no significant difference between the mean CSA after a 4-mm ALA simulation using radiographs and that using 3D models based on preoperative CT data, which suggests that radiographs are comparable with 3D CT data models as a reliable modality for the preoperative simulation of ALA.

Level of Evidence

III, retrospective comparative study.

Lateral Acromioplasty With the Aim of Reducing the Critical Shoulder Angle Using Techniques Based on the Lateral Acromial Border Result in Larger-Than-Necessary Resections

Purpose

Methods

Results

Conclusions

Clinical relevance

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.

Implication of bone morphology in degenerative rotator cuff lesions: A prospective comparative study between greater tuberosity angle and critical shoulder angle

BACKGROUND

Degenerative rotator cuff tear is a frequent and multifactorial pathology. The role of bone morphology of the greater tuberosity and lateral acromion has been validated, and can be measured with two plain radiographic markers on true anteroposterior views: the greater tuberosity angle (GTA) and the critical shoulder angle (CSA). However, the interdependence of both markers remains unknown, as well as their relationship with the level of professional and sports activities involving the shoulder. The aim of this prospective comparative study was to describe the correlation between the GTA and CSA in patients with degenerative rotator cuff tears.

HYPOTHESIS

GTA and CSA are independent factors from one another and from demographic factors, such as age, dominance, sports, or professional activities.

PATIENT AND METHODS

All patients presenting to a shoulder specialized clinic were assigned to two groups. The first consisted of patients with a symptomatic degenerative rotator cuff tear visible on MRI and the control group consisted of patients with any other shoulder complaints and no history or visible imaging of any rotator cuff lesion.

RESULTS

There were 51 shoulders in 49 patients in the rotator cuff tear group (RCT) and 53 shoulders in 50 patients in the control group. Patient demographics were similar in both groups. Mean GTA was 72.1°±3.7 (71.0-73.1) in the RCT group and 64.0°±3.3 (63.1-64.9) in the control group (p<0.001). Mean CSA was 36.7°±3.7 (35.7-37.8) in the RCT group, and 32.1°±3.7 (31.1-33.1) in the control group (p<0.001). A summation of GTA and CSA values over 103° increased the odds of having a rotator cuff tear by 97-fold (p<0.001). There was no correlation between GTA and CSA, nor between GTA or CSA and age, sex, tear size, or dominance. Patients with different levels of professional and sports activities did not have significantly different GTA or CSA values.

CONCLUSION

GTA and CSA are independent radiologic markers that can reliably predict the presence of a degenerative rotator cuff tear. A sum of both values over 103° increases the odds of having a rotator cuff tear by 97-fold. These markers are not correlated with patient demographic or environmental factors, suggesting that the variability of the native acromion and greater tuberosity morphology may be individual risk factors for rotator cuff tear.

LEVEL OF EVIDENCE

II; diagnostic study.

Does isolated arthroscopic anterior acromioplasty modify critical shoulder angle?

INTRODUCTION

Critical shoulder angle (CSA)>35° correlates significantly with primary rotator cuff tear and re-tear after repair. Acromial axial orientation varies between individuals. The present study aimed to assess the impact of strictly anterior acromioplasty on CSA.

HYPOTHESIS

CSA is reduced by arthroscopic anterior acromioplasty.

MATERIAL AND METHODS

A single-center retrospective study included patients receiving isolated arthroscopic acromioplasty between January 2016 and December 2017. Exclusion criteria comprised history of surgery and fracture or dislocation of the shoulder. Pre- and post-operative AP shoulder radiographs were taken. The angle subtended by a line between the inferior and superior edges of the glenoid and a line between the inferior edge of the glenoid and the most lateral point on the acromion was measured.

RESULTS

One hundred and two patients were included: mean age, 50.5±10.1 years (range, 23-82 years). Mean CSA was 34.7±4.4° (range, 26-48°) preoperatively and 31.7±3.7° (range, 23-40°) postoperatively (p<0.001). In the group with CSA >35°, the decrease was significant: 34.4±3.2° (range, 28-40°) versus 38.9±2.8° (range, 36-48°) (p<0.001), with 64% CSA <35° after isolated anterior acromioplasty.

DISCUSSION

CSA was decreased by arthroscopic acromioplasty. However, in 36% of cases with preoperative CSA >35°, CSA was not normalized.

CONCLUSION

Anterior arthroscopic acromioplasty significantly reduced CSA in the overall population, and especially in case of high CSA.

LEVEL OF EVIDENCE

IV; retrospective study.

Critical shoulder angle (CSA): age and gender distribution in the general population

Objective

Anatomical parameters and pathologies that can affect the critical shoulder angle (CSA) are subjects of discussion. To date, we do not know if the CSA value changes in the different decades of life in a population characterized by the same ethnicity, nor if there are differences related to gender or side. This study hypothesizes that age and gender may affect the CSA.

Methods

Patients older than 15 years old affected by a shoulder trauma and who were discharged with a diagnosis of shoulder contusion were enrolled. A true AP view of the shoulder was obtained as well as data regarding age and gender of all participants. The CSA was measured by three authors, and interoperator reliability was assessed. Eight subcategories, according to decades of life, were considered. Finally, the studied population was divided into three subcategories according to CSA values (< 30°; 30–35°; ≥ 35°).

Results

The initial sample comprised 3587 shoulder X-rays. The interobserver reproducibility was high, with an intraclass correlation coefficient of 0.865 (95% CI 0.793–0.915).

Two thousand eight hundred seventy-three radiograms were excluded. The studied group comprised 714 patients [431 females, 283 males; mean age (SD): 47.2 (20.9) years, range: 11–93 years]. The mean CSA was 33.6° (range: 24–50°; SD: 3.9°). The mean CSA values in females and males were 33.7°and 33.5°, respectively. The mean CSA values of the right and left shoulders were 33.3° and 33.9°, respectively (p > 0.05). Linear regression analysis showed a CSA increase by 0.04° every year. The mean CSA in subjects aged between 15 and 19 years was significantly lower than all the other groups, except for patients older than 80 years.

No significant differences were found between CSA subcategories, gender, or side.

Conclusions

In the general population, the mean CSA value was 33.6°. No significant differences were found regarding the mean CSA value according to gender or side. A significant positive linear correlation between CSA and age was detected. In each decade of life, the CSA value, which is genetically determined, shows a large variability.

Level of evidence: IV.

Does the critical shoulder angle decrease after acromioplasty? A systematic review and meta-analysis

BACKGROUND

Rotator cuff tears are one of the most common shoulder injuries in the older population. This study aimed to determine whether acromioplasty reliably decreases the critical shoulder angle (CSA) and describe any associated complications.

METHODS

A systematic literature review was performed according to PRISMA guidelines using PubMed, EMBASE, Web of Science, and Cochrane Library Database. Two reviewers independently screened the titles and abstracts using prespecified criteria. Studies where the acromioplasty was performed as a surgical procedure were included. Patient characteristics and degree of CSA reduction were collected from each individual study. All statistical analyses were performed using Review Manager (RevMan) 5.4.1 software. A random-effects model was used for meta-analysis.

RESULTS

A total of 9 studies involving 1236 patients were included in the meta-analysis. The age of patients ranged from 23 to 82 years. The follow-up period ranged from 12 to 30 months. Of the 9 studies, 8 (88.9%) were retrospective, 1 (11.1%) was prospective, 5 were comparative, and 4 were case series. The mean CSA was significantly reduced from 36.1° ± 4.6° to 33.7° ± 4.2 (p < 0.05). The meta-analysis showed an overall best estimate of the mean difference in pre- and postoperative CSA equal to 2.63° (95% confidence interval: 2.15, 3.11] (p < 0.00001).

CONCLUSIONS

Acromioplasty can significantly reduce CSA, notably in cases of high preoperative CSA. In addition, the effect of lateral acromioplasty on the CSA was more significant compared to anterolateral acromioplasty. Acromioplasty was not associated with complications during the short-term follow-up.

Effect of Abduction Brace Wearing Compliance on the Results of Arthroscopic Rotator Cuff Repair

The benefit of protective bracing after rotator cuff reconstruction has been debated for many years, although immobilization compliance has never been assessed objectively to date. In a previous study, compliance with the wearing of an abduction brace was measured for the first time with use of temperature-sensitive sensors. The purpose of the present follow-up study was to assess the effect of immobilization compliance on tendon-healing after rotator cuff repair.

Critical shoulder angle does not influence retear rate after arthroscopic rotator cuff repair

PURPOSE

The critical shoulder angle (CSA) has been implicated as a potential risk factor for failure following arthroscopic rotator cuff repair (RCR). However, there is conflicting evidence regarding the clinical usefulness of this measurement. Given these discrepancies and limited comparisons to clinical outcomes, the aim of the current study was to determine whether higher CSAs correlated with an increased retear rate after arthroscopic rotator cuff repair and to determine if any association between CSA and patient-reported outcomes (PROs) exists. It was hypothesized that there would be no correlation between CSA and retear rate or PROs after arthroscopic rotator cuff repair.

METHODS

A total of 164 patients who underwent arthroscopic RCR were retrospectively reviewed. CSA was measured for each patient. Patients were then divided into a retear group of 18 patients and a non-retear group of 146 patients. Patient-reported outcomes (PROs), including PROMIS 10 score, American Shoulder and Elbow Surgeons (ASES) score, Brophy score, and visual analog pain scores (VAS) were recorded post-operatively.

RESULTS

The average CSA was 31.2 ± 4.5° for the retear group and 32.2 ± 4.7° for the non-retear group (n.s.). No correlations were found between CSA and PROMIS score (n.s.), ASES score (n.s.), Brophy score (n.s.), or VAS (n.s.).

CONCLUSION

Critical shoulder angle had no correlation to retear rate or patient-reported outcomes. CSA should not be used as a clinical predictor to assess rotator cuff retear risk after arthroscopic RCR.

LEVEL OF EVIDENCE

Level III.

Biconcave glenoids show 3 differently oriented posterior erosion patterns

BACKGROUND

Posterior glenoid wear remains a challenge in anatomic and reverse total shoulder arthroplasty (rTSA) because of an asymmetric erosion with altered retroversion. The purpose of this study was to assess glenoid morphology and evaluate the influence of acromial orientation in posterior glenoid erosion patterns by using 3-dimensional (3D) models.

MATERIAL AND METHODS

Computed tomographic (CT) shoulder scans from 3 study centers of patients awaiting rTSA between 2017 and 2018 were converted into 3D models and analyzed by 2 observers. Morphology, orientation and greatest depth of erosion, inclination, current retroversion and premorbid retroversion, surface areas of the glenoid, and external acromial orientation and posterior acromial slope were assessed. Measurements were compared between wear patterns, glenoid erosion entities, and genders.

RESULTS

In the complete cohort of 68 patients (63.8 ± 10.0 years; 19 female, 49 male), a mean of 85.9° (±22.2°) was observed for the glenoid erosion orientation. Additionally, a further distinct classification of the glenoid erosion as posterior-central (PC, n = 39), posterior-inferior (PI, n = 12), and posterior-superior (PS, n = 17) wear patterns was possible. These wear patterns significantly (P < .001) distinguished by erosion orientation (PC = 86.9° ± 12.0°, PI = 116.3° ± 10.3°, PS = 62.3° ± 18.9°). The greatest depth of erosion found was 7.3 ± 2.7 mm in PC wear patterns (PC vs. PI: P = .03; PC vs. PS: n.s.; PI vs. PS: n.s.). Overall, the observed erosion divided the glenoid surface into a paleoglenoid proportion of 48% (±11%) and a neoglenoid proportion of 52% (±12%). For the complete cohort, glenoid inclination was 85.4° (±6.6°), premorbid glenoid retroversion was 80.7° (±8.1°), and current glenoid retroversion was 73.4° (±7.4°), with an estimated increase of 6.9° (±6.0°). The mean external acromial orientation was 118.2° (±8.9°), and the mean posterior acromial slope was 107.2° (±9.6°). There were no further significant differences if parameters were compared by wear patterns, entities, and gender.

CONCLUSION

Three significantly differently oriented wear patterns (posterior-superior, posterior-central, and posterior-inferior) were distinguished in shoulders demonstrating posterior wear on axillary imaging. No significant differences between the observed erosion patterns or any relevant correlations were found regarding the orientation of the acromion.

Radiographic shoulder parameters and their relationship to outcomes following rotator cuff repair: a systematic review

BACKGROUND

Anatomic parameters, such as the critical shoulder angle and acromion index, have emerged as methods to quantify scapular anatomy and may contribute to rotator cuff pathology. The purpose of this paper is to investigate the published literature on influences of scapular morphology on the development of re-tears and patient-reported outcomes following rotator cuff repair.

METHODS

A systematic review of the Embase and PubMed databases was performed to identify published studies on the potential influence of scapular bony morphology and re-tear rates and patient-reported outcomes after rotator cuff repair. Studies were reviewed by two authors.

RESULTS

A total of 615 unique titles and 49 potentially relevant abstracts were reviewed, with eight published manuscripts identified for inclusion. Two of three papers reported no relationship between these acromion index and rotator cuff re-tear rate, while one paper found an increased re-tear rate. All three studies on critical shoulder angle found a significant association between critical shoulder angle and cuff re-tear rate. There was no clear relationship between any bony morphologic measurement and patient-reported outcomes after rotator cuff repair.

CONCLUSIONS

Rotator cuff re-tear rate appears to be significantly associated with the critical shoulder angle and glenoid inclination, while not clearly associated with acromial morphologic measurements.

The Effect of Acromial Morphology on the Functional Outcomes of Degenerative Rotator Cuff Tear Surgery

PURPOSE

The aim of this study was to investigate how the critical shoulder angle (CSA) and acromion index (AI) affect the outcome of arthroscopic rotator cuff tear (RCT) repair.

METHODS

A total of 287 patients, who underwent arthroscopic surgery due to degenerative rotator cuff tear, were evaluated. The Constant Shoulder Score (CSS), Oxford Shoulder Score (OSS) and Visual Analogue Scale (VAS) were evaluated preoperatively and postoperatively. The AI and CSA were measured on true anteroposterior shoulder radiographs. The patients were separated into two groups according to their CSA and AI values (control group ≤ 38°, increased CSA > 38°, and control group ≤ 0.7, increased AI > 0.7). The relationship between CSS, OSS and VAS was examined in all the groups.

RESULT

The evaluation was made of a total of 287 patients with a mean age of 60.29 ± 8.55 years. The mean duration of follow-up of the patients was 34.00 ± 18.97 months (range 12-80 months). There was a statistically significant difference between the preoperative and postoperative clinical scores of the patients (p < 0.05). No relationship was determined between CSA, AI and CSS, OSS or VAS during follow-up (p > 0.05). The interobserver ICC for CSA and AI were determined to be 0.962 and 0.967, respectively (95% CI) indicating a high correlation (p < 0.001).

CONCLUSION

CSA and AI do not affect functional outcomes in the postoperative period, so they are not significant at the time of degenerative arthroscopic rotator cuff repair decisions.

WITHDRAWN: Does anterior arthroscopic acromioplasty modify critical shoulder angle?

This article has been withdrawn because we accidentally published the same article twice due to an error by the Managing editor/Elsevier. The correct version of the article has been published later in Orthop Traumatol Surg Res, 108 (2022) 103040, https://doi.org/10.1016/j.otsr.2021.103040. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal

Rotator Cuff Healing

The present article broadly addresses the aspects that interfere with the healing process of the rotator cuff. Life habits, such as smoking and alcoholism, are considered, systemic factors such as diabetes mellitus, hypertension, and obesity, as well as local factors, among which are those related to the pre, peri, and postoperative periods. From an extensive literature review, with the citation of 60 scientific articles from both Western and Eastern literature, the authors intend to deepen the theme by bringing to medical practice conducts based on new established concepts.

Effectiveness of measuring tension during arthroscopic rotator cuff repair

Purpose

Arthroscopic rotator cuff repair (ARCR) for relatively small rotator cuff tears (RCTs) has shown promising results; however, such surgery for larger tears often results in failure and poor clinical outcomes. One cause of failure is over-tension at the repair site that will be covered with the tendon stump. Reports on the clinical outcomes using ARCR with tension ≤ 30 N are lacking. This study aimed to evaluate ARCR outcomes and failure rates using less tension (30 N) and to assess the prognostic factors for failure.

Methods

Our study group comprised of 118 patients who underwent ARCR for full-thickness RCTs with full tendon stump coverage of the footprint with a tension of ≤ 30 N, measured using a tension meter; no additional procedures, such as margin convergence or footprint medialisation, were performed. The failure rate was calculated, and the prognostic factor for failure was assessed using multivariate regression analyses.

Results

There were seven cases of failure in the study group. Postoperatively, flexion and internal rotation ranges of motion, acromiohumeral interval, muscle strength, and clinical results improved significantly. Using multivariate regression analyses, intraoperative concomitant subscapularis tendon lesion and pre-operative infraspinatus tendon retraction, assessed using radial-sequence magnetic resonance imaging, were significantly correlated with post-ARCR failure using less tension (p = 0.030 and p = 0.031, respectively).

Conclusion

ARCR is likely to succeed for RCTs that can be extracted using tension ≤ 30 N. However, cases with more severe subscapularis tendon lesions and those with high infraspinatus tendon retraction may show surgical failure.

Level of evidence

LEVEL IV Retrospective case series

The Ratio of the Transverse to Longitudinal Diameter of the Glenoid Projection Is of Good Predictive Value for Defining the Reliability of Critical Shoulder Angle in Nonstandard Anteroposterior Radiographs

PURPOSE

To investigate (1) whether measurement of the critical shoulder angle (CSA) is still reliable in some nonstandard anteroposterior radiographs; and (2) whether the ratio of the transverse to longitudinal diameter of the glenoid projection (RTL) could be used to determine the reliability of the CSA in nonstandard anteroposterior radiographs.

METHODS

The authors analyzed radiology records from 2017 to 2019 for patients with computed tomography (CT) scans of the shoulder. According to the Suter-Henninger classification system, each CT scan underwent 3-dimensional (3D) reconstructions to obtain 8 digitally reconstructed radiographs (DRRs), including 1 type A1 film and 7 type D1 films with different rotation angles. CSA and RTL were measured on all films, and 2 blinded reviewers evaluated DRRs. The relationship between RTL and CSA was determined by Pearson correlation test. The threshold value was determined by receiver operating characteristic (ROC) analyses using RTL as predictors and defined reliable CSA as criterion in the logistic regression. Intra- and inter-rater reliability were assessed by the intraclass correlation coefficient (ICC). Discriminative capacity was calculated with ROC analyses and area under the curve (AUC). An optimal measurement cutoff with resultant sensitivity and specificity was calculated.

RESULTS

A total of 86 patients were included, mean age 40.70 ± 18.25 years, 19 of whom had rotator cuff tears (RCTs) and 67 without RCTs. Spearman's correlation test revealed that the deviation of CSA was positively correlated with RTL, correlation coefficient 0.544 (P < .001) in all patients and 0.686 (P < .001) only in patients with RCTs. ROC analysis of all patients showed that the AUC of the RTL was 0.90, and the optimal cutoff point was 0.25 (sensitivity 88%, specificity 87%). ROC analysis only of patients with RCTs showed that the AUC of the RTL was 0.95, and the optimal cutoff point was 0.22 (sensitivity 95%, specificity 92%).

CONCLUSION

The ratio of the transverse to longitudinal diameter of the glenoid projection (RTL) is of good predictive value in defining the reliability of the CSA in malposition films. Based on the results, the CSA can be considered reliable if its RTL is <0.25.

LEVEL OF EVIDENCE

III, retrospective cohort study investigating a diagnostic test.

Effect of arthroscopic acromioplasty on reducing critical shoulder angle: a protocol for a prospective randomized clinical trial

Background

The critical shoulder angle (CSA), which helps to predict patients who are at risk of rotator cuff tears (RCTs) with large degree and who are susceptible to osteoarthritis with low angle, has been identified as one of the most vital acromial parameters; anterolateral and lateral acromioplasties have been proven to be valid ways to reduce CSA. However, no study has compared the effect of different acromioplasties on the reduction of the large CSA (≥33°) clinically. Additionally, either anterolateral or lateral acromioplasty could not precisely correct large CSAs to a favorable range (30–33°) in each patient. Thus, we will propose a novel precise acromioplasty technique for the purpose of reducing CSA accurately and effectively, and compare the effectiveness of different acromioplasties on the reduction of the CSA.

Methods

A total of 60 RCT patients who have indications for arthroscopic rotator cuff repair and with pre-operative CSA ≥33° will be recruited in outpatient center of Sun Yat-sen Memorial Hospital. Eligible participants will be randomly allocated to Group A (anterolateral acromioplasty), Group B (lateral acromioplasty) or Group C (precise acromioplasty) via a random, computer-generated number system. Three surgical plans will be made for each participant respectively by one professional surgeon according to the results of randomization allocation. The post-operative CSA will be measured 2 days post-operation. Follow-up will be maintained at 3, 6, and 12 months after surgery including the visual analog scale score, the University of California at Los Angeles score, the Constant Shoulder Score and the American Shoulder and Elbow Surgeon Shoulder Assessment Form. Finally, all outcomes will be assessed by two researchers who are blinded to the recruitment and allocation.

Discussion

This is the first clinical trial to evaluate the impact of different acromioplasties on the reduction of the CSA. Additionally, this study will provide a new precise acromioplasty technique, which is a novel precision and individualized treatment to prevent degenerative RCTs by reducing the CSA.

Trial registration

ChiCTR2000032343. Registered on April 26th, 2020.

Lateral Acromioplasty has a Positive Impact on Rotator Cuff Repair in Patients with a Critical Shoulder Angle Greater than 35 Degrees

BACKGROUND

A Critical Shoulder Angle (CSA), evaluated on plain radiographs, greater than 35° is considered predictive of rotator cuff tears. The present prospective comparative study aimed, firstly, to develop a formula to calculate the amount of acromion that should be resected performing a lateral acromioplasty and, secondly, verify whether lateral acromioplasty to reduce the CSA associated with arthroscopic cuff repair decreased the rate of recurrence of the tears, and impacted favorably on clinical postoperative outcomes.

METHODS

Patients undergoing arthroscopic rotator cuff repair (RCR) for rotator cuff tears with a CSA greater than 35° were included in this study and divided into two groups, based on whether the CSA had been reduced by arthroscopic resection of the lateral portion of the acromion. A new mathematical formula was developed in order to quantify the amount of bone to be resected while performing the lateral acromioplasty. Patients with traumatic tears, previous surgery, osteoarthritis or plain radiographs, not classified as A1 according to Suter-Henninger, were excluded. Clinical and radiographic outcomes were assessed at a minimum of 2 years of follow-up considering the tear size.

RESULTS

289 patients were included in this study. Thirty-seven were lost to follow-up. Group A (Lateral acromioplasty) patients included: 38 small tears, 30 medium tears, 28 large tears and 22 massive tears; Group B (control group) was composed of 40 small tears, 30 medium tears, 30 large tears and 23 massive tears. The Constants Score value and retear Rate were, respectively, significant higher (p = 0.007 and p = 0.004) and lower (p = 0.029 and p = 0.028) in Group A, both in the Small-and Medium-size subgroups. No complications were outlined. The mediolateral width of the acromion was reduced, according to the preoperatively calculated measure.

CONCLUSION

Arthroscopic lateral acromioplasty decreased the CSA within the favorable range (30°-35°) in all patients treated, resecting the amount of bone predicted by the mathematical formula. Lateral acromioplasty is a safe and reproducible technique which may prevent recurrence of rotator cuff tears in patients with small and medium lesions.

LEVEL OF EVIDENCE

II.

Long-term follow-up of patients with a high critical shoulder angle and acromion index: is there an increased retear risk after arthroscopic supraspinatus tendon repair?

BACKGROUND

The effect of the acromion index (AI) and critical shoulder angle (CSA) on the short-term healing rate after arthroscopic repair of the supraspinatus tendons is already known. Long-term effects have not been published yet.

PURPOSE

Long-term evaluation of the effect of the AI and CSA on the postoperative healing rate and clinical results after arthroscopic repair of the supraspinatus tendon.

METHODS

Patients with a symptomatic, single-tendon, full-thickness supraspinatus tear in whom nonoperative management had failed were treated with an arthroscopic repair. Preoperative radiographs were used to measure CSA and AI. Eight years postoperatively, magnetic resonance imaging (MRI) studies were performed and evaluated on repair integrity. Patient-reported outcome measurements were collected pre- and postoperatively.

RESULTS

Thirty-one patients were evaluated 8 years postoperatively. The mean age at the time of surgery was 61 ± 9 years. MRI evaluation showed that 20 patients (65%) had an intact repair and 11 (35%) had a full-thickness retear. No significant differences were found between the intact and retear groups regarding age (P = .605), initial tear size (P = .485), retraction grade (P = .439), and all PROMs. The mean CSA for the intact group (33° ± 1°) was significantly lower than the CSA in the retear group (38° ± 1°; P = .004). Eighteen patients (58%) had a CSA ≥35°, and 9 (50%) among them had a retear and 9 (50%) had an intact repair.The mean AI for the intact group (0.72 ± 0.11) was significantly lower than the AI in the retear group (0.81 ± 0.08 ; P = .021). Seventeen patients (55%) had an AI ≥0.75, and 9 (53%) among them had a retear and 8 had an intact repair. If the AI was ≥0.75, the odds ratio of having a retear was 6.19 (P = .045). No progressive worsening of PROMs and clinical results could be demonstrated related to a higher CSA or AI during the entire follow-up.

CONCLUSION

At long-term follow-up, a higher CSA has the tendency to have an increased rate of retear after arthroscopic supraspinatus tendon repair, but this was not significant. A higher AI significantly increased the retear risk. A higher CSA and AI did not impair the clinical results over time. An AI ≥0.75 was associated with a 6-fold increase in risk of retear after arthroscopic supraspinatus tendon repair.

Patients With Diabetes Mellitus Have a Higher Risk of Tendon Retear After Arthroscopic Rotator Cuff Repair: A Meta-analysis

Background

Retear of a repaired rotator cuff tendon is a major issue for shoulder surgeons. It is possible that diabetes mellitus (DM) is associated with a greater risk of tendon retear after arthroscopic rotator cuff repair.

Purpose

To determine whether patients with DM have a higher tendon retear risk after arthroscopic rotator cuff repair.

Study Design

Systematic review; Level of evidence, 4.

Methods

A systematic review was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines using the Web of Science, PubMed, and Embase databases. Inclusion criteria were articles written in the English language that included patients undergoing arthroscopic rotator cuff repair surgeries, reported the numbers of patients with and those without DM, and reported the number of rotator cuff retears. Data relevant to this study were extracted and statistically analyzed. Random-effects models were used to generate pooled odds ratio estimates and CIs.

Results

A total of 160 studies were identified from the initial search, and 5 of them met the inclusion criteria. A total of 1065 patients (207 patients with DM and 858 patients without DM) were included. The pooled results showed that the patients in the DM group had a significantly higher tendon retear risk than did those in the non-DM group (relative risk, 2.25; 95% CI, 1.14-4.45; P = .02).

Conclusion

Patients with DM have a 2.25 times higher risk of tendon retear after arthroscopic rotator cuff repair compared with patients without DM.

The Effect of Acromioplasty on the Critical Shoulder Angle and Acromial Index

Purpose

To evaluate the effect of acromioplasty using a cutting block technique on bony coverage as measured by the critical shoulder angle (CSA) and acromial index (AI).

Methods

This study is a retrospective radiographic review using data from a previous prospective randomized clinical trial that offered enrollment to patients aged 18 years or older with a full-thickness tear of the superior rotator cuff between October 2007 and January 2011. Each patient was allocated to repair with either acromioplasty using a cutting block technique or non-acromioplasty treatment arms in a blinded fashion. Medical and demographic information was recorded for each patient. Between January 2017 and December 2017, patients were contacted for repeat follow-up clinical evaluation and radiographs. Measurements of acromial index and critical shoulder angle were performed on pre- and postoperative radiographs by a single reviewer.

Results

Seventy-one (75%) patients were available for follow up. The 2 groups were similar in terms of baseline demographics and acromial type. When compared with preoperative measures, acromioplasty did not result in significant reductions in mean CSA (34.5° vs 35.5°; P = .293) or AI (0.68 vs 0.66; P = .283). Furthermore, postoperative CSA (34.5° vs 36.2°, P = .052) and AI (0.66 vs 0.67, P = .535) demonstrated no statistically significant differences between patients with and without acromioplasty, respectively.

Conclusions

There was no statistically significant change in either the CSA or AI following acromioplasty, nor was there a significant postoperative difference in CSA or AI between the group that underwent acromioplasty and the group that did not.

Clinical Relevance

Some studies suggest a greater postoperative CSA may result in greater risk of retear after arthroscopic rotator cuff repair. The CSA and AI may not be modifiable with acromioplasty.

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.

Does anterior acromioplasty reduce critical shoulder angle?

INTRODUCTION

Critical shoulder angle (CSA) is the angle between glenoid inclination and the lateral edge of the acromion. CSA>35° has been shown to be a risk factor for primary and iterative rotator cuff tendon tear. The present study aimed to assess change in CSA after anterior acromioplasty. The study hypothesis was that CSA is significantly reduced.

METHOD

A single-center retrospective descriptive observational study included patients undergoing open or arthroscopic anterior acromioplasty, with strict AP pre- and post-operative radiographs. Patients with radiographs not meeting Moor's criteria were excluded.

RESULTS

One hundred and forty-eight patients were included: arthroscopy, 112; open surgery, 36. Mean age was 57.8 years (range, 29-80 years). Mean preoperative CSA was 36.1±4.25° (range, 25-48.4°) and postoperative CSA 33.5±3.9° (23.8-45.2°), for a significant reduction of -2.6±2.5° (p=0.001). Surgical technique did not affect change in CSA: open surgery, -2.3±1.9° (-6.3° to -1°); arthroscopy, -2.7±2.7° (-10.5° to -5°) (p=0.06). In pathologic CSA (>35°), the mean reduction was -3.2±2.6° (-10.5°to -5°). CSA normalized below the 35° threshold in 48% of patients.

DISCUSSION

Despite reduction in CSA, the 35° threshold for iterative tear is not always reached after anterior acromioplasty. Complementary strictly lateral resection is theoretically required. However, change in CSA is difficult to predict intraoperatively.

CONCLUSION

Anterior acromioplasty significantly reduced CSA, independently of technique and preoperative value.

LEVEL OF EVIDENCE

IV, retrospective descriptive study.

Reduced acromiohumeral distance and increased critical shoulder angle: implications for primary care clinicians

Objectives: The literature indicates that reduced acromiohumeral distance (AHD) and increased critical shoulder angle (CSA) are associated with large and massive rotator cuff (RC) tears which may not be amenable to a successful repair. The purpose of this study was to examine the overall accuracy of these two radiographic features in diagnosing significant RC pathology. Methods: This was a diagnostic study of patients with shoulder pain. To examine the overall accuracy of the measurements, the area under the Receiver Operating Characteristic curves (AUC) were calculated. The validity indices (sensitivity, specificity and likelihood ratios) examined the predictive value of specific cutoff categories of AHD<6 mm and the CSA >35°. Results: Data of 200 consecutive patients; mean age: 59(11), 117 males were used for analysis. There was a weak inverse correlation (r = 0.46) between the AHD and CSA. The AUCs for presence and size of RC tear and different stages of fatty infiltration of supraspinatus and infraspinatus muscles varied from fair to excellent for AHD and poor to good for CSA. Specificity was high for the cutoff categories of both AHD and CSA (>90%). The positive LRs were large for AHD and small to moderate for CSA. Conclusion: The AHD and CSA were reliably measured in the true AP radiographic view. Both radiographic features (AHD<6mm and CSA>35°) were able to confirm the presence of a major RC pathology. However, the AHD<6 mm, an acquired radiologic abnormality secondary to failure of the RC muscles/tendons had better measurement properties. This information is of value to primary care physicians, sports medicine specialists and advanced practice physiotherapists in their clinical decision making.

Hypo-High-Density Lipoproteinemia Is Associated With Preoperative Tear Size and With Postoperative Retear in Large to Massive Rotator Cuff Tears

PURPOSE

To evaluate any association of specific subtypes of dyslipidemia with increments of preoperative tear size and with structural integrity after arthroscopic rotator cuff repair (ARCR).

METHODS

One surgeon's consecutive patients who underwent ARCR from January 2011 to June 2018 were reviewed. The inclusion criteria were minimum 1-year follow-up ultrasonography, blood tests, physical examination, and provision of informed consent. The exclusion criteria were incomplete laboratory tests, history of acute trauma, previous shoulder surgery, isolated subscapularis tendon tear, inappropriate radiographs, no 1-year follow-up ultrasonography, and medication with lipid-lowering drugs. Associated preoperative factors for the increments of tear size and for retear after ARCR were determined using logistic regression analysis. Statistical significance was set at P < .05.

RESULTS

Of the 502 ARCR patients from the study period, 195 patients (195 shoulders), with a mean age of 60.5 ± 7.5 years, met the inclusion and exclusion criteria. Age (odds ratio [OR], 1.2; 95% confidence interval [CI], 1.1-1.3), diabetes (OR, 3.6; 95% CI, 1.7-7.5), and hypo-high-density lipoproteinemia (hypo-HDLemia) (OR, 2.9; 95% CI, 1.5-5.6) were significantly associated with increments of preoperative tear size (P ≤ .01). Diabetes (OR, 3.0; 95% CI, 1.3-6.6), critical shoulder angle (OR, 2.0; 95% CI, 1.4-3.0), and tear size (OR, 2.1; 95% CI, 1.3-3.4) were significantly associated with retear after ARCR in overall study subjects (P = .01). Diabetes (OR, 3.8; 95% CI, 1.3-11.4), hypo-HDLemia (OR, 3.0; 95% CI, 1.1-8.8), and critical shoulder angle (OR, 1.5; 95% CI, 1.1-2.3) had significant associations with retear after ARCR in patients with a large to massive preoperative tear size (P ≤ .04).

CONCLUSIONS

Preoperative hypo-HDLemia (high-density lipoprotein level < 40 mg/dL in male patients and < 50 mg/dL in female patients) has a significant association with the increments of preoperative tear size and with retear after ARCR in large- to massive-sized rotator cuff tears.

LEVEL OF EVIDENCE

Level IV, case series.

The natural course of and risk factors for tear progression in conservatively treated full-thickness rotator cuff tears

BACKGROUND

The natural course of and risk factors for tear progression in full-thickness rotator cuff tears (FTRCTs) have not been clarified yet. The study's purpose was to retrospectively evaluate tear progression in FTRCTs by using magnetic resonance imaging (MRI) and to identify risk factors that are relevant to such tear progression.

METHODS

Between June 2010 and September 2019, a total of 345 patients with FTRCTs who had been diagnosed via MRI were treated conservatively. Of these, 48 patients who underwent post-treatment follow-up MRI were retrospectively enrolled. Tear progression was defined as significant when the tear size increased by >5 mm.

RESULTS

The mean MRI follow-up duration was 22 ± 14 months (range, 12-65 months). Among the 48 patients (mean age, 69 years; range, 53-81), 26 (54%) and 20 (41%) showed medial-lateral (M-L) and anterior-posterior (A-P) tear progression on MRI follow-up. Multivariate analysis revealed that MRI follow-up duration (P = .011), diabetes mellitus (P = .017), and infraspinatus muscle atrophy (P = .011) were independent risk factors for tear progression in the A-P plane. A high critical shoulder angle (P = .011) and supraspinatus (P = .024) and infraspinatus (P = .020) muscle atrophy were risk factors associated with M-L tear progression.

CONCLUSION

Among the assessed patients, a considerable number of FTRCTs increased in size during the follow-up period. Severe infraspinatus muscle atrophy was the independent risk factor for exacerbation of A-P and M-L tear progression.

Critical shoulder angle is intrinsically associated with the development of degenerative shoulder diseases: A systematic review

Aim of this study was to investigate the potential influence of Critical Shoulder Angle (CSA) as a predisposing factor for the development of degenerative full-thickness rotator cuff tears (DRCT) or primary glenohumeral osteoarthritis (PGOA). A systematic review of the Pubmed, Scopus, Mendeley, ScienceDirect and the Cochrane Central Register of Controlled Trials online databases was performed for literature regarding CSA and its association with DRCT and PGOA. In order to evaluate solely the relationship between CSA as a predisposing factor for the development of the aforementioned degenerative shoulder diseases (DSDs), we precluded any study in which traumatic cases were not clearly excluded. Our search strategy identified 289 studies in total, nine of which were eligible for inclusion based on our pre-established criteria. Quality assessment contacted using the Newcastle Ottawa Scale for case-control studies. There were a total of 998 patients with DRCT and 285 patients with PGOA. The control groups consisted of a total of 538 patients. The mean CSA ranged from 33.9° to 41.01° for the DRCT group, from 27.3° to 29.8° for the PGOA group and from 30.2° to 37.28° for the control group. All studies reported statistically significant differences between the DRCT and PGOA groups and the respective control groups. Our study results showed that there is moderate evidence in the literature supporting an intrinsic role of CSA in the development of DSDs. Level of evidence: IV. Systematic review of diagnostic studies, Level II-IV.

WITHDRAWN: Does anterior arthroscopic acromioplasty modify critical shoulder angle?

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The Relationship Between the Critical Shoulder Angle and the Incidence of Chronic, Full-Thickness Rotator Cuff Tears and Outcomes After Rotator Cuff Repair: A Systematic Review

PURPOSE

To summarize the available evidence and examine the relationship between the critical shoulder angle (CSA) and (1) the incidence of chronic full-thickness rotator cuff tears (RCTs) and (2) outcomes after rotator cuff repair (RCR).

METHODS

A comprehensive search of MEDLINE, Embase, and CINAHL was completed. Comparative studies were included and the influence of the CSA on either the incidence of chronic, full-thickness RCTs, or outcomes following RCR was evaluated. Demographic variables and outcomes were collected.

RESULTS

Seven comparative studies analyzed the influence of the CSA on the incidence of chronic, full-thickness RCTs (the control group constituted patients with a normal rotator cuff). High heterogeneity limited pooling of studies, but the majority concluded that a greater CSA significantly increased the likelihood of a chronic, full-thickness RCT. Conversely, 5 comparative studies analyzed the influence of CSA on outcomes following RCR, and although a greater CSA was associated with a greater re-tear rate, the majority reported that CSA did not significantly influence postoperative functional outcomes, including patient-reported outcome measures (PROMs), range of motion (ROM), and strength.

CONCLUSIONS

Based on the available evidence, there appears to be a relationship between a greater CSA and the presence of a chronic, full-thickness RCT. Furthermore, a greater CSA may be associated with a greater re-tear rate following RCR; however, CSA does not appear to influence functional outcomes following RCR. Despite these observations, the available evidence is of poor quality, and the clinical utility and role of the CSA in the diagnosis and surgical management of a chronic, full-thickness RCT remains in question.

LEVEL OF EVIDENCE

Level IV: Systematic review of Level II-IV studies.

Does an Increased Critical Shoulder Angle Affect Re-tear Rates and Clinical Outcomes Following Primary Rotator Cuff Repair? A Systematic Review

PURPOSE

To determine if an increased critical shoulder angle (CSA) predisposes patients to higher re-tear rates and worse clinical outcomes after rotator cuff (RC) repair.

METHODS

A comprehensive search of the PubMed, MEDLINE, and EMBASE databases was performed in October 2018 for English-language studies pertaining to RC repair and an increased CSA in accordance with Preferred Reported Items for Systematic Reviews and Meta-analyses guidelines. Studies of all levels of evidence were included provided that any outcomes, including pain, patient-reported outcomes, and re-tear rates, were reported.

RESULTS

Of a group of 1126 studies that satisfied the initial search criteria, 6 studies were included in the final analysis, comprising data from 473 patients. Three comparative studies were assessed for an association between increased CSA and RC re-tear rates. Among these 3 studies that compared RC re-tear rate in patients with larger and smaller CSAs, 22 of 97 patients (23%) with a larger CSA had a RC re-tear in comparison to 10 of 99 patients (10%) with a smaller CSA. All 3 studies demonstrated higher RC re-tear rates in patients with larger CSAs (risk ratio, 2.39-9.66, I² = 7%.) The mean CSA in those patients who did not have RC re-tears ranged from 34.3° to 37°, and the mean CSA in those patients who had RC re-tears ranged from 37° to 40°.

CONCLUSION

RC re-tear rates were higher in patients with larger CSAs among comparative, nonrandomized studies. However, the heterogeneity of the relevant literature limits the strength of his observation. Based on the current literature, it remains unclear as to whether lateral acromioplasty affects clinical outcomes as a function of a reduced postoperative CSA.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II to IV studies.

The Effect of Critical Shoulder Angle on Clinical Scores and Retear Risk After Rotator Cuff Tendon Repair at Short-term Follow Up

The authors aimed to investigate whether standard acromioplasty can reduce critical shoulder angle (CSA) effectively and to investigate the effects of postoperative CSA on the clinical outcomes and retear rates. Patients are divided in to three groups: group 1 (24 patients): CSA under 35° before surgery, group 2 (25 patients): CSA over 35° before surgery and under 35° after surgery and group 3 (17 patients): CSA over 35° before and after surgery. Standard acromioplasty was performed if CSA is over 35 and no acromioplasty was performed if the CSA is already under 35. Preoperative and postoperative CSAs, UCLA, Constant-Murley clinical score and visual analog scale (VAS) pain score were measured. The size of the rotator cuff tear was classified by the Patte classification in preoperative MRI and the quality of the repair was evaluated as retear if discontinuity detected in the postoperative first year MRI. There were 31 female and 35 male patients with a mean age of 59.3 ± 4.5 years (range, 48–68) at the time of surgery. The mean CSA is reduced from 37.8° ± 1.4 to 34.9° ± 1.2 (p < 0.001) significantly for patients who underwent acromioplasty. In 25 (59.5%) of the 42 patients, the CSA was reduced to under 35°, whereas in the other 17 (40.5%) patients, it remained over 35°. The mean Constant and UCLA score was 46.4 ± 6.6; 18.5 ± 1.6 preoperatively and 82.4 ± 6.2; 31.1 ± 1.9 postoperatively respectively (p < 0,001). The mean VAS decreased from 4.94 ± 1.09 to 0.79 ± 0.71 (p < 0.001). No Clinical difference was seen between patients in which CSA could be reduced under 35° or not in terms of Constant-Murley score, UCLA and VAS score. Retear was observed in 2 (8.3%) patients in group 1, in 4 (16%) patients in group 2 and in 3 patients (17.6%) in group 3. There was not any significant difference between the patients who had retear or not in terms of neither the CSA values nor the change of CSA after the surgery. Standard acromioplasty, which consists of an anterolateral acromial resection, can reduce CSA by approximately 3°. This is not always sufficient to decrease the CSAs to the favorable range of 30°–35°. In addition, its effect on clinical outcomes does not seem to be noteworthy.

Editorial Commentary: Critical Shoulder Angle: Perhaps Not So "Critical" for Clinical Outcomes Following Rotator Cuff Repair

The critical shoulder angle (CSA) has been associated with the development of rotator cuff pathology. More recent studies have also identified a correlation between an increased CSA and recurrent tears after arthroscopic rotator cuff repair. Although this observation is significant, several studies have failed to identify a correlation between CSA and clinical outcomes after rotator cuff repair. As a result, the usefulness of this measurement, and the need to address it with lateral acromioplasty, remains ill defined. Further research is required to demonstrate an association between CSA and clinical outcomes before treatment algorithms should be altered.