Process of neovascularisation compared with pain intensity in tendinopathy of the long head of the biceps brachii tendon associated with concomitant shoulder disorders, after arthroscopic treatment. Microscopic evaluation supported by immunohistochemical markers of the endothelial cells

Background: Tendinopathy of the long head of the biceps brachii tendon (LHBT) is one of the most common, painful conditions of the anterior part of the shoulder and often coexists with rotator cuff tears. Multifactorial aetiopathology of tendinopathy is poorly understood; however, several studies indicated that it is seen predominantly in areas with decreased vascularity of the tissue; the pathology is also characterised by expansive and abundant neovascular in-growth. The aim of the study was to investigate the relationship between the neovascularisation of proximal part of the LHBT and pain along the bicipital groove. Materials and methods: Tissue material was obtained from 28 patients who underwent a shoulder arthroscopy and experienced pain along the bicipital groove measured using Visual-Analog Scale (VAS) score. CD31 and CD34 molecules were visualised by immunohistochemical method to assess biceps tendon neovascularisation and quantify it based on a Bonar scoring system. Results: Although all patients reported pain prior to arthroscopy (mean VAS score was 7.5), microscopic examination did not reveal neovascularisation in all cases. Immunohistochemical staining for CD31 and CD34 allowed for very precise visualisation and quantification of neovascularisation; however there was also no correlation between vessels in-growth scores and pain. Conclusions: The obtained data suggest that neovascularisation process in tendinopathy is not directly related to pain; however, further studies are needed to explain its significance in the LHBT tendinopathy.