Suprascapular notch variations: a 3DCT study

Background Although cadaveric studies have revealed suprascapular notch shape variations, few have investigated the association between suprascapular notch variation and age or gender. The purpose of this study was to investigate suprascapular notch shape variations by use of three-dimensional computed tomography (3DCT) and to determine if there was any association with age or gender. Methods Three-dimensional CT images of 762 shoulders of 762 patients were analyzed in this study. Participants comprised 404 men and 358 women, with an average age of 58.2 ± 19.1 years. Suprascapular notch shape variations were classified into six types on the basis of Rengachary’s classification. Results Of the total study population, 11.4 % were classified as type I, 23.5 % as type II, 30.1 % as type III, 14.8 % as type IV, 15.9 % as type V, and 4.3 % as type VI. Average age was 56.5 ± 20.5 years for type I, 57.0 ± 19.5 years for type II, 55.5 ± 20.0 years for type III, 56.4 ± 18.5 years for type IV, 65.5 ± 14.4 years for type V, and 68.0 ± 13.4 years for type VI. Statistically significant age differences were found between types I–IV and V, between types I–IV and VI, and between the non-ossification group (types I–IV) and the ossification group (types V and VI). Male-to-female ratio among each type, and between the non-ossification group and the ossification group, were not statistically significantly different. Conclusions Our results suggest that transverse scapular ligament ossification is associated with aging whereas individual variation explains differences among types I, II, III, and IV. Three-dimensional CT provides useful information for arthroscopic resection of the transverse scapular ligament, when the wide variety of suprascapular notch shape variations is considered. Level of evidence Level IV