The critical shoulder angle, the acromial index, the glenoid version angle and the acromial angulation are associated with rotator cuff tears

Abstract

PurposeTo compare the critical shoulder angle (CSA), acromion index (AI), acromion angulation (AA) and glenoid version angle (GVA) between patients with full‐thickness rotator cuff tears (RCTs) and patients with intact rotator cuffs. MethodsBetween 2014 and 2018, the CSA, AI, AA and GVA were measured in consecutively included patients aged > 40 years who underwent shoulder arthroscopy for full‐thickness RCTs. A total of 437 patients with RCTs and a mean age of 51.2 years (± 5.8) were included, 35.7% of whom were male. In the control group, there were n = 433 patients (36.3% male) with an intact rotator cuff, and the mean age was 50.7 years (± 5.3). ResultsThe mean AI for the RCT group was 0.7 ± 0.1, which was significantly higher than the mean AI for the control group (0.6 ± 0.1, p < 0.001). The mean CSA for the RCT group was 33.6° ± 3.9°, which was significantly higher than the mean CSA for the control group (31.5° ± 4°, p < 0.001). The mean AA for the RCT group was 13.9° ± 9°, which was significantly higher than the mean AA for the control group (12.4 ± 8.6, p = 0.012). The mean GVA for the RCT group was − 3.5° ± 4.6° and significantly retroverted compared with the mean GVA for the control group (− 2.2° ± 4.6°, p < 0.001). The cutoff values determined by the ROC curve analyses were as follows: 0.6 for AI, 31.4° for CSA, 9.6° for AA and − 2.6° for GVA. ConclusionThe CSA, AI, GVA and AA values measured by MRI were determined to be significantly related to full‐thickness rotator cuff ruptures. The AI, CSA, AA and GVA may be considered risk factors for degenerative rotator cuff tears. Assessing the CSA, AI, GVA and AA can be helpful for diagnostic evaluation of patients with full‐thickness RCTs. Level of evidenceIII.

What Factors Are Associated with Symptomatic Rotator Cuff Tears: A Meta-analysis

“…The critical shoulder angle can be measured on radiographs instead of MRI, and if a patient has shoulder pain and a high critical shoulder angle, one should have a high index of suspicion that the patient may have a rotator cuff tear. Prior studies have disagreed on whether greater glenoid retroversion is associated with rotator cuff tears [18,28,32,36]; our meta-analysis found that it is. Based on this, surgeons might further study the biomechanical effect of glenoid version angle on rotator cuff.…”

Neither critical shoulder angle nor acromion index were related with specific pathology 20 years later!

“…The clinical implications of our results are that the CSA and AI measures should be questioned as important prognostic factors for the development of RCT or GH OA and that lateral acromioplasty probably does not prevent RCT’s as suggested [ 14 , 25 ].…”

“…The acromion anatomy has been described to influence, or even elicit, development of different shoulder pathologies. Lately two measures, critical shoulder angle (CSA) and acromial index (AI), first described by Moor et al [ 19 ] and Nyffeler et al [ 21 ] have been found associated with rotator cuff tears (RCT) or glenohumeral osteoarthritis (GH OA) [ 2 , 7 , 8 , 11 , 14 , 19 , 21 , 23 , 24 , 28 ]. It has also been suggested that CSA and AI values, in combination with established risk factors such as trauma and age, may predict the integrity of the rotator cuff [ 20 , 26 ].…”

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

“…The critical shoulder angle (CSA) describes the lateral extension of the acromion in relation to the inclination of the glenoid and has been demonstrated to be an effective predictor for the development of shoulder pathology. 1 , 2 , 3 , 4 Numerous studies have documented that shoulders with a CSA of less than 30° were likely to be osteoarthritic, whereas a CSA of greater than 33-35° was associated with rotator cuff tears (RCTs). 5 , 6 , 7 , 8 , 9 , 10 Gerber et al.…”