2015 ISAKOS Biennial Congress ePoster #2404

Association of the Scapular Morphology With Degenerative Rotator Cuff Tears: Prospective Study

Vivek Pandey, MBBS, MS(Orth), Udupi, Karnataka INDIA
Deepu Vijayan, MBBS, Udupi INDIA
Sandeep Tapashetti, MBBS, Udupi INDIA
Lipisha Agarwal, MBBS, Udupi INDIA
Kasturba Medical College, Manipal, Manipal University, Udupi, Karnataka, INDIA

FDA Status Not Applicable

Summary: There is a strong association between acromial spur and lateral extension of acromion with degenerative rotator cuff tear

Abstract:

Introduction

Degenerative rotator cuff tear is one of the commonest cause of shoulder pain. Current evidence suggests that distinct scapular morphologies especially overhanging (anterior and lateral) acromion may accelerate the underlying degenerative process in the cuff. The objective of this prospective longitudinal study was to evaluate the relationship between symptomatic degenerative rotator cuff tear (complete & partial) and different radiographic acromial characteristics including acromion shape, indices (acromial index [AI] and critical shoulder angle [CSA]) and presence of acromial spur.

Method

Priori power analysis determined minimum sample size (n=51) in each group to give adequate power to the study. Prospective longitudinal case series from 2012 December to May 2014 encompassing 166 cases divided in three age- sex controlled groups [Group 1 (n=54), degenerative full thickness tear; Group 2 (n=51), partial thickness degenerative cuff tear and Group 3 (n=61), normal cuff]. Patients were evaluated with bilateral standard AP and outlet view radiograph and bilateral ultrasonography scan. Patients with full thickness tear also underwent arthroscopic confirmation and repair. Basic demographic data (age, sex, side of involvement) was noted. Measurements of acromion index, critical shoulder angle, type of acromion and acromion spur were noted. The results were analyzed using SPSS (v16.0, IBM, USA).

Results

Mean age of patients in group 1, 2 & 3 was 57.8, 55.1 & 53.4 years respectively. Interobserver interclass coefficient demonstrated excellent agreement for AI (0.879) and CSA (0.946). The presence of an acromial spur was highly associated with full-thickness rotator cuff tear (p=0.001, odd’s ratio =3.5). Mean (+ SD) AI and CSA in group 1 was 0.76 (+0.099) and 41.05 (+3.10). Both AI and CSA are strongly correlated with full thickness cuff tear (p= 0.03 and 0.04). AI and CSA show significant relationship with full thickness supraspinatus tear (p=0.009; 0.000 respectively) when compared with group 3. However, there was no correlation between AI and CSA of group 2-3 (p=0.09, 0.12 respectively) and AI between group 1 & 2 (p=0.69). But there was significant correlation between CSA of group 1 and 2 (p=0.02). Taking CSA and AI in account, Logistic regression model suggested 67% predictability in full thickness cuff tear. AI had higher odd’s ratio (7.7) as compared to CSA (1.2) in predicting full thickness cuff tear. Using receiver operating characteristic (ROC) curve, AI and CSA showed area (0.661 and 0.738 respectively) which indicates fair reliability of the test. There was no association was found between the acromial morphology according to Bigliani and rotator cuff tear (p>0.05).

Conclusion

The study showed presence of acromion spur is strongly associated with full thickness cuff tear. Higher AI and CSA indicate increased lateral extension of acromion which is strongly associated with full thickness tear. AI is more strongly associated with full thickness cuff tear with higher odd’s ratio. The type of acromion do not show relation to type of rotator cuff tear (complete or partial).