An investigation of supraspinatus tendon samples obtained from patients undergoing arthroscopic repair of a rotator cuff tear revealed:
1. Cartilage-like changes in rotator cuff. According to the researchers stress-shielded and transversely-compressed side of the enthesis of the rotator cuff has a distinct tendency to develop cartilage-like or atrophic changes in response to the lack of tensile load. The formation of cartilage-like changes in the enthesis in many ways can be considered a physiological adaptation to the compressive loads.
2. Rotator cuff tendons also show frequently marked changes on articular side of the rotator cuff under arthroscopic vision.
3. Over a long period, this process (described above) may develop into a primary degenerative lesion in that area of the tendon.
4. According to the authors these above 3 points explains well why the tendinopathy is not always clearly activity related, and can be strongly correlated with age.
5. The authors due to above said reason authors have emphasized rotator cuff injuries to be considered as an ”underuse” injury rather than an overuse injury as a result of stress-shielding.
6. The authors also revealed another grave picture in rotator cuff tendon tears. According to them, tendon changes are not only localized at the site of rupture, but also in the macroscopic intact tendon portion.
7. Finally authors have found a correlation of plasma glucose levels in non diabetic patients with rotator cuff tear. Normal, but in the high range of normal, increasing plasma glucose levels may be a risk factor for rotator cuff tear.
Comments of Karim Khan in British journal of sports medicine