Variations of the micro-vascularization of the greater tuberosity in patients with rotator cuff tears.

Purpose: The aim of the study was to analyse greater tuberosity's (GT) micro-vascularization in the context of rotator cuff tear and to identify factors that could affect the rate and distribution of micro-vessels.

Methods: Eighty-seven patients with supraspinatus and/or infraspinatus tendon tears were included in a prospective study. Mean age at surgery was 58 years (41-78) and clinical symptoms were lasting from an average of 20 months before surgery. A bone core of 1-cm depth was obtained from the GT during rotator cuff repair at two localizations, medial and lateral within tuberosity. Micro-vascularization was then analysed with an immunohistochemistry technique based on CD34 antigen tracking endothelial cells at two levels of depth for each sample (more and less than 5 mm). Epidemiologic and pathologic data were correlated with the rate of micro-vascularization measured.

Results: Median rate of GT's micro-vascularization was 9.8 %, which ranged from 0.13 % to 33.4 %. This rate decreased with preoperative steroid injection (7.4 % vs 11.2) and with localization close to the cartilage of the humeral head (8.7 % vs 11.9 %). However, it remains almost homogenous along the depth's core. Moreover, no significant correlation was found regarding age at surgery, gender, context of previous trauma, smoking habits, duration of symptoms, and specific data regarding the tendon tear.

Conclusions: This study highlighted the variability of GT's micro-vascularization in case of rotator cuff tear. A greater rate was observed at the lateral part of the footprint, whereas medical history of steroid injection has a negative influence on micro-vascularization.