The in vivo effect of platelet-rich plasma (PRP) on supraspinatus tendon morphology and subacromial bursa cell gene expression in degenerative rotator cuff tears remains unclear. This randomized controlled trial evaluated the effect of preoperative leukocyte-poor PRP (LP-PRP) subacromial injection on supraspinatus tendon histology and subacromial bursa gene expression. Sixteen patients with full-thickness supraspinatus tears were randomized to receive an ultrasound-guided LP-PRP injection (n = 8) or no injection (n = 8) six weeks before arthroscopic repair. Tendon biopsies were assessed using the modified Movin score. Gene expression of collagen type I, II and III, metalloproteinase 3 and 13, and interleukin 1β and 6 genes from subacromial bursa cells was quantified using quantitative real-time PCR. The results of the two groups were compared to determine any statistically significant difference regarding all the examined parameters. The PRP group demonstrated a significantly lower total modified Movin score than controls (6.5 vs. 12.1, p = 0.002), with lower scores for fiber structure, fiber arrangement, nuclear rounding, inflammation and cell density (all p 0.05), although collagen II and metalloproteinase 3 and 13 showed biologically relevant downregulation fold change 0.23 (95%CI 0.05–1.09), 0.24 (95%CI 0.002–26.10), and 0.26 (95%CI 0.02–2.76), respectively. The LP-PRP injection was associated with improved supraspinatus tendon histological characteristics and biologically relevant reductions in selected bursal genes, in the setting of supraspinatus tendon tear.
Pitsilos et al. (Thu,) studied this question.