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

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.

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 role of scapular morphology in traumatic rotator cuff tears and greater tuberosity fractures: A retrospective study

Background

Traumatic postero-superior Rotator Cuff Tears (RCT) and isolated Greater Tuberosity fractures (GTF) are equivalent injuries resulting in significant shoulder dysfunction if left retracted or displaced. The difference in morphometric aetiology is unclear. A raised critical shoulder angle (CSA) has been associated with rotator cuff degeneration. We hypothesised that traumatic RCT is associated with a raised CSA when compared to GTF.

Methods

A retrospective study was conducted across the two trauma units in our institution. All patients between the period of 2010 and 2020 with Traumatic GTF or RCT assessed on cross-sectional imaging (CT or MRI) were identified. Patients were case-matched by age, gender, mechanism and laterality of injury. The primary outcome measurement was the Critical Shoulder Angle (CSA). Other radiographic features of subacromial degenerative change, mechanism of injury, association with shoulder dislocation and delay to diagnosis were also compared.

Results

Eighty patients met the inclusion criteria(40 traumatic RCT and 40 GTF). The mean age was 61.8 years with 58(72.5%) left-sided injuries. Thirty-four (43%) were female.The mean CSA was 3.96° higher in the RCT group (95% CI 2.5 to 5.41, p < 0.05). A CSA of 33.73 gave a sensitivity of 0.68 and a specificity of 0.8 to differentiate between RCT and GTF. Patients with RCT were far more likely to display subacromial degenerate changes and experience a significant delay in diagnosis, whereas those with GTF were more likely to have suffered a shoulder dislocation.

Conclusions

Patients with traumatic RCT have radiographic features and scapular morphology associated with degenerative rotator cuff disease compared to those with GTF. This supports the theory that tears occur on the background of pre-existing tendon degeneration. Careful assessment of these parameters, combined with clinical assessment, may help guide the provision of appropriate diagnostic imaging.

Level of evidence

III.

Computer Image-Guided Precise Acromioplasty for Reducing the Critical Shoulder Angle

The shoulders with critical shoulder angle (CSA) of greater than 33-35° are associated with rotator cuff tears, whereas a CSA of less than 30° is likely to be osteoarthritic. However, anterior acromioplasty or lateral acromioplasty could not reduce high CSAs to the desired range (30-33°), with satisfactory accuracy and efficacy. Thus, we introduce a computer image-guided precise acromioplasty (CIG-PAP) technique, an individualized treatment based on three-dimensional planning. We believe that the introduction of this technique will provide an alternative approach to reduce a large CSA to the desired range (30-33°).

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.

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.

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.

Increased preoperative greater tuberosity angle does not affect patient-reported outcomes postarthroscopic rotator cuff repair

Background

The greater tuberosity angle (GTA) is a newly described radiological parameter identified in a 2018 study by Cunningham et al that sought to investigate the effect of GT morphology on cuff tears. Increased GTA has been conceptualized to affect rotator cuff pathology through both extrinsic and intrinsic mechanisms. GTA > 70° was highly predictive of a degenerative rotator cuff tear. This study seeks to examine if increased GTA predicts for worse functional outcomes 2 years postoperatively after arthroscopic rotator cuff repair.

Methods

Between May 2010 and December 2016, 169 patients who underwent arthroscopic rotator cuff repair with subacromial decompression were included in this study. GTA was measured on preoperative radiographs. These patients were evaluated preoperatively and at 3 months, 6 months, 1 year, and 2 years postoperatively. Outcomes were assessed with the Visual Analog Scale Pain score, Constant Shoulder Score, and the Oxford Shoulder Score. Power analysis was performed based on the minimal clinically important difference of the Constant Shoulder Score. Statistical analysis was performed by dividing patients into two groups based on GTA: 1) ≤ 70 (control GTA); and 2) >70 (increased GTA) and comparisons were made between the 2 groups.

Results

The patients’ demographics were comparable between both groups. All 169 patients had statistically significant improvements in all functional scores at 2 years postoperatively. There were no statistically significant differences between the two groups of patients in Visual Analog Scale and functional scores at 3 months, 6 months, 1 year, and 2 year postoperatively. The changes in functional scores from their preoperative baseline were also tabulated, and there were no statistically significant differences between the 2 groups. Finally, there was no significant correlation between GTA with CSS or Oxford Shoulder Score at 2 years follow-up.

Conclusion

This study represents the largest single series available investigating the influence of GTA on midterm functional outcomes after arthroscopic rotator cuff repair. Although GTA remains a reliable radiographic predictor of rotator cuff tears, the authors conclude that increased GTA does not negatively influence midterm functional outcomes. As there is also no statistical significance between increased GTA vs. control in relative functional gain 2 years postoperatively, corrective tuberoplasty may not be mandatory during arthroscopic repair of cuff tears. Standard arthroscopic double-row rotator cuff repair with subacromial decompression can still be offered as a suitable treatment option.

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.