The Biomechanical and Histologic Effects of Platelet-Rich Plasma on Rat Rotator Cuff Repairs

Abstract

Background Rotator cuff tears are common injuries that are often treated with surgical repair. Because of the high concentration of growth factors within platelets, platelet-rich plasma (PRP) has the potential to enhance healing in rotator cuff repairs. Hypothesis Platelet-rich plasma would alter the biomechanical and histologic properties of rotator cuff repair during an acute injury response. Study Design Controlled laboratory study. Methods Platelet-rich plasma was produced from inbred donor rats. A tendon-from-bone supraspinatus tear was created surgically and an immediate transosseous repair performed. The control group underwent repair only. The PRP group underwent a repair with PRP augmentation. Rats in each group were sacrificed at 7, 14, and 21 days. The surgically repaired tendons underwent biomechanical testing, including failure load, stiffness, failure strain, and stress relaxation characteristics. Histological analysis evaluated the cellular characteristics of the repair tissue. Results At 7- and 21-day periods, augmentation with PRP showed statistically significant effects on the biomechanical properties of the repaired rat supraspinatus tear, but failure load was not increased at the 7-, 14-, or 21-day periods (P = .688, .209, and .477, respectively). The control group had significantly higher stiffness at 21 days (P = .006). The control group had higher failure strain at 7 days (P = .02), whereas the PRP group had higher failure strain at 21 days (P = .008). Histologically, the PRP group showed increased fibroblastic response and vascular proliferation at each time point. At 21 days, the collagen fibers in the PRP group were oriented in a more linear fashion toward the tendon footprint. Conclusion In this controlled, rat model study, PRP altered the tissue properties of the supraspinatus tendon without affecting the construct’s failure load. Clinical Relevance The decreased tendon tissue stiffness acutely and failure to enhance tendon-to-bone healing of repairs should be considered before augmenting rotator cuff repairs with PRP. Further studies will be necessary to determine the role of PRP in clinical practice.

Biologic and Tissue Engineering Strategies for Tendon Repair

“…PRP collagen fibers were more organized and thicker than in the control. Aside from slight infiltration by hypertrophic chondrocytes during the first 7 days, the PRP treatment did not have any negative effects but did not aid or accelerate healing [86].…”

Growth factor delivery vehicles for tendon injuries: Mesenchymal stem cells and Platelet Rich Plasma

“…In addition, when different factors are added they inhere the potential to differentiate into tenocytes [77][78][79][80][81][82] . Animal studies revealed that both, PRP and MSCs, have the potential to improve histological and biomechanical properties of regenerated tendons [29][30][31]71,72,75,[91][92][93]95,97,98 . Application of MSCs even resulted in regeneration of the enthesis in a rat model 7,91,92 .…”

“…Application of MSCs even resulted in regeneration of the enthesis in a rat model 7,91,92 . Although the benefits from PRP seemed to be encouraging in preclinical studies [28][29][30][31] , PRP failed to prove significant, reproducible impact on regeneration in patients [42][43][44][45][46][48][49][50][51][52] . This is the reason why further studies are needed to improve the capabilities of the PRP use 54 .…”

Complete Rotator Cuff Tear: An Evidence-Based Conservative Management Approach

“…In an experiment in which rats were treated for RCT, the group given the PRP treatment demonstrated better collagen linear alignment. Furthermore, the research team found positive effects when administering the PRP injections 3 weeks after the initial surgery [76].…”