Collagen and PRP in Partial Thickness Rotator Cuff Injuries. Friends or Only Indifferent Neighbours? Randomized Controlled Trial

INTRODUCTION: Partial thickness rotator cuff injuries (PTRCI) is the sum of degenerative, overload and microtrauma processes, external supply of collagen and platelet-rich plasma (PRP) could potentially counteract deterioration of degenerative tendinopathy.AIM: Comparison of the effectiveness: collagen with PRP, PRP alone, collagen alone in the treatment of PTRCI.METHODS: Ninety patients with PTRCI treated with US–guided injections into the shoulder bursa every consecutive week: Group A - collagen with PRP (n=30), B - collagen alone (n=30), C - PRP alone (n=30). Primary outcomes: numeric rating scale (NRS), QuickDash and EQ-5D-5L questionnaires in control points: IA (initial assessment), T1, T2, T3 – after 6, 12 and 24 weeks, respectively. Secondary outcomes: number of patients with loss of RC continuity, number of regenerated RC between IA and T3.RESULTS: No statistical difference between groups in primary outcomes, tendency for further improvement in A and C group (opposite to group B) between T2 and T3. The RC discontinuity (n = 3, one case in each group) and RC regeneration (n = 65; 73%, 67% and 77%, in group A, B and C, respectively).CONCLUSIONS: Combined therapy of collagen and PRP in PTRCI is not more effective than monotherapies with collagen or PRP. (clinicaltrials.gov - NCT04492748)