Platelet-rich plasma for enhancing surgical rotator cuff repair: evaluation and comparison of two application methods in a rat model

Platelet-rich plasma (PRP) is a natural concentrate of autologous growth factors now being widely tested in different fields of medicine for its potential in enhancing the regeneration of tissue with low healing potential. However, studies of PRP in enhancing rotator cuff repair have been contradictory, perhaps because of how PRP is administered. The purpose of this study is to evaluate the effect of PRP and compare two different application methods of PRP on rotator cuff healing. The supraspinatus tendons of 48 mature, male Wistar-Albino rats were detached from their insertion on the humerus. The animals were divided into four groups: (1) no repair, (2) primary repair, (3) repair plus PRP injections into the tendon-bone interface, and (4) repair plus PRP absorbed from a sponge carrier to the tendon-bone interface. The tendons were evaluated biomechanically and histologically at week 8. Cuffs repaired with PRP had significantly greater mean (SD) load-to-failure rates [11.1 (6.5) and 11.6 (3.9) N; P < 0.05] and stiffness [3.5 (2.3) and 1.6 (0.75) N; P < 0.05] than did cuffs repaired without PRP. The groups receiving PRP did not differ significantly on these variables. Histological evaluation showed no significant differences among the four groups. The application of PRP, independent of the application method, significantly improved biomechanical properties at the rotator cuff tendon-bone interface. The type of application, injection or absorption from a sponge did not influence the effect of PRP on rotator cuff healing.