Table 1. Age distributionAge (in Our Study Worland et al39 Yamamoto A, Takagishi K,years) % % Osawa T, et al.1210-19 3 20 – 29 17 – A logistic regression30 – 39 18 – analysis revealed the40 – 49 16 13 risk factors for a rotator50 – 59 23 40 cuff tear to be a history60-69 13 – of trauma and age>70 10 Epidemiological studies support a relationship between age and cuff tear prevalence as per degeneration microtrauma theory.40 Hashimoto et al.
described seven characteristic features of such age-related degeneration in cadaveric specimens: thinning and disorientation of the collagen fibers (100%), myxoid degeneration (100%), hyaline degeneration (100%), vascular proliferation (34%), fatty infiltration (33%), chondroid metaplasia (21%) and calcification (19%). Of these, only vascular proliferation and fatty infiltration were more common on the bursal side relative to the articular side. The authors supposed that these two changes reflected reparative processes, with the remaining features representing primarily degenerative changes. 41 Table 2 – Gender distribution:Gender Our Study Helena Miranda, Eira % Viikari-Juntura, Sami Heistaro et al.
42 Male 58.45 The prevalence didFemale 41.55 not differ markedlyTotal 100 between men and women Though the gender distribution in our study shows Male: Female ratio was 1.41:1, most of the studies have reported that, there is no marked difference in prevalence.Table 5 – Supraspinatus tendon tear:Supraspinatus Percentage P Goyal, U Hemal,tendon tear R Kumar et al43Partial 40.5 Partial thicknessFull 47.
3 were more commonIntrasubstance 1.2 than full thicknessIn our study full thickness tear was most common followed by partial thickness tear and intrasubstance.Table 6 – Acromion Type (MRI findings)Acromion Type Our Study (%) Schippinger G, Bailey D, McNally EG, et al 19974Type I38.9 32.3Type II 58.
4 67.7Type III 1.6 0Type IV 1.
1 0The most common acromion type seen was type II – 121 cases (67.7%).These results imply that the hooked acromion is not present in the normal population and is, therefore, likely to be an acquired abnormality. 4 In our study -Subscapularis tendon tears showed 71 % sensitivity, 97 % specificity, a PPV of 83 % and a NPV of 95 %.Supraspinatus tendon tears showed 81 % sensitivity, 92 % specificity, a PPV of 97% and a NPV of 61 %. Infraspinatus tendon tears shows 80 % sensitivity, 100 % specificity, 100 % PPV and 95 % NPV.
None of the 49 cases had teres minor tendon involvement, hence it was not evaluated. Teefey et al demonstrated an overall accuracy of 87% for both modalities in correctly identifying partial- and full-thickness rotator cuff tears as well as the absence of such tears. In that study, US helped correctly identify 45 of 46 full-thickness tears and 13 of 19 partial-thickness tears, whereas MR imaging helped correctly identify all 46 full-thickness tears and 12 of 19 partial-thickness tears. The reported accuracy, sensitivity, and specificity of US in the detection of any tear, whether partial or full thickness, are all greater than 90% 8The USG criteria for detection of partial thickness tears were focal discontinuity of the tendon either at the bursal or articular margin.
The USG criteria for full thickness tears were recognized by complete absence of the tendon.The space over the humeral head is filled by the deltoid muscle and a thickened subacromial-subdeltoid bursa.Tendinosis was diagnosed by USG, in the form of thinning of the tendon and heterogeneous echotexture.MRI criteria for detection of partial thickness tears are characterized by a focal region of fiber discontinuity that is filled with fluid signal. Beside a focal tendon defect, additional findings included surface fraying or changes in tendon caliber, such as attenuation or thickening.
MRI criteria for full thickness tears were characterized by tendon discontinuity. Tendon retraction was another sign to detect full thickness tears. The presence of fluid in the subacromial-subdeltoid bursa, although not specific for a full-thickness tear, is considered to be another indirect sign.
For partial thickness tears,• Subscapularis tear – USG had a sensitivity of 71.4 %, specificity of 97.6 %, PPV of 83.3 % and NPV of 95.4 %.• Supraspinatus tear – USG had a sensitivity of 84.
6 %, specificity of 94.7 %, PPV of 91.7 % and NPV of 90.0 %.
• Infraspinatus tear – USG had 60 % sensitivity, 100 % specificity, 100 % PPV and 95 % NPV.For full thickness tears,• Subscapularis tear – USG had a 100 % sensitivity, specificity, PPV and NPV.• Supraspinatus tear – USG had a sensitivity of 94.
1 %, specificity of 100 %, PPV of 100 % and NPV of 94.7 %.• Infraspinatus tear – had 100 % sensitivity, specificity, PPV and NPV.In our study, the USG findings were correlated with MRI findings.
However, MRI additionally picked up labral tears, IGHL thickening and muscle atrophy, osseous involvement.