Effects of glenoid inclination and acromion index on humeral head translation and glenoid articular cartilage strain
Section snippets
Materials and methods
We used a generic numerical model of the shoulder to vary independently the lateral extension of the acromion and GI (Figure 2, Figure 2).19, 36 The model was developed from magnetic resonance imaging (MRI) scans of a 27-year-old healthy male volunteer showing no signs of glenohumeral, acromioclavicular, or sternoclavicular joint disorders. MRI scans were obtained using a specific protocol consisting of two 3-dimensional T1-weighted sequences on a 3-T MRI scanner (Trio; Siemens Healthcare,
Results
In comparison with the reference, the relative humeral head inferior-superior translation was positively correlated with both GI and AI (Fig. 3). The correlation with GI was very strong, whereas the correlation with AI was moderate (Table I). However, the relative inferior-superior translation was statistically significantly (P = .0005) higher for large AI (+10.5%) than for small AI (−12.0%). On average, the effect of GI was 1.6 times larger than the effect of AI. The multiple correlation with
Discussion
Several clinical studies reported a statistical correlation between scapular anatomy and the occurrence of degenerative shoulder diseases. GI and AI were associated with rotator cuff tendon tears and glenohumeral osteoarthritis.17, 27, 29, 31, 39, 41 In this study, we used a biomechanical shoulder model to evaluate the relative effects of these 2 different anatomic parameters on upward translation of the humeral head and glenoid articular cartilage strain. Assuming the hypothesis that humeral
Conclusion
CSA is a combination of GI and AI. It efficiently represents the effects of these 2 parameters on humeral head migration because both GI and AI have the same positive effect. For articular cartilage strain, CSA seems less relevant because GI and AI have opposite effects. Consequently, CSA might be a good indicator of the risk of tendon tear, but AI might be more efficient to predict the risk of osteoarthritis. Although degenerative shoulder diseases are known to be multicausal, anatomic
Disclaimer
This study was supported by the Swiss National Science Foundation (K-349 32K1_122512) and the Center for Biomedical Imaging of Lausanne University Hospital.
The authors, their immediate families, and any research foundations with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.
Acknowledgments
The authors thank Jean-Baptiste Ledoux for help with MRI data acquisition.
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2021, Seminars in Arthroplasty JSESCitation Excerpt :The mechanism by which increased inclination affects clinical outcomes in likely varied. A great deal of recent literature outside of total shoulder arthroplasty has focused on the critical shoulder angle and inclination as it relates to the rotator cuff [2,4,6]. Daggert et al noted in their series of patients undergoing total shoulder arthroplasty that glenoid inclination is linearly correlated with the critical shoulder angle and is significantly increased in patients with massive rotator cuff tears [4].
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
2021, Arthroscopy - Journal of Arthroscopic and Related SurgeryCitation Excerpt :A CSA value of 30° to 35° was considered normal, whereas a CSA >35° was associated with degenerative RCTs.26 In a recent study, the CSA was proven to be the most accurate radiographic predictor for degenerative RCTs on standard anteroposterior films,20 and these results were supported and confirmed by other studies.26-28 Therefore, the CSA has garnered increasing popularity for the prediction of rotator cuff injuries and their prognosis.16,29,30
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2020, Journal of Shoulder and Elbow SurgeryCitation Excerpt :Similarly, extrinsic factors such as manual labor34 and osseous anatomy of the shoulder33 have been extensively analyzed in the so-called outlet impingement syndrome. Whereas initial theories postulated a compression of the supraspinatus tendon between the humeral head and the acromion as a possible cause of bursal-sided tears due to friction and abrasion,3,32 newer finite element analysis,16 biomechanical,17 and clinical studies31 have shifted the focus from the anterior to the lateral extension of the acromion when diagnosing and treating subacromial pathologies. Several procedures to correct an unfavorable acromial shape have been described.1,2,4,19,24,32
The Critical Shoulder Angle Shows a Reciprocal Change in Magnitude When Evaluating Symptomatic Full-Thickness Rotator Cuff Tears Versus Primary Glenohumeral Osteoarthritis as Compared With Control Subjects: A Systematic Review and Meta-analysis
2020, Arthroscopy - Journal of Arthroscopic and Related SurgeryThe Effectiveness of Using the Critical Shoulder Angle and Acromion Index for Predicting Rotator Cuff Tears: Accurate Diagnosis Based on Standard and Nonstandard Anteroposterior Radiographs
2019, Arthroscopy - Journal of Arthroscopic and Related SurgeryCitation Excerpt :Blonna et al.23 found that larger CSAs were associated with an increased prevalence of RCTs. A recent study comparing the precision of diagnosis using the CSA or AI on standard AP films concluded that the CSA was the most accurate radiographic predictor for degenerative RCTs,6 and these results were supported and confirmed by other studies.10,24 Our findings were also consistent with these studies.6,10