[The effect of platelet-rich plasma on graft healing in reconstruction of the anterior cruciate ligament of the knee joint: prospective study].

PURPOSE OF THE STUDY Growth factors produced by platelets enhance tissue healing. The aim of this study was to confirm or disprove the hypothesis that, in anterior cruciate ligament (ACL) reconstruction, the application of platelet-rich plasma (PRP) into the tibial and femoral tunnels and in the graft enhances graft maturation and graft-bone interface healing and thus improves knee function at 3 and 12 months post-operatively in comparison with the control group. MATERIAL AND METHODS A total of 40 patient had the surgery; 20 underwent single-bundle hamstring reconstruction with PRP application (PRP group) and 20 had the same surgery without PRP addition (control group). A 5 ml amount of PRP was obtained from the patient's peripheral blood. A graft inserted in the bone tunnels was fixed with interference screws and, after intra-articular fluid aspiration, 1 ml of PRP was injected into each tunnel and 3 ml were evenly applied to the intra-articular portion of the graft. The patients were examined by MRI at 3 and 12 months after surgery. The subsidence of swelling in the tunnelsurrounding tissues was taken as a sign of graft-bone interface healing, and increased signal intensity of the graft was considered as a result of its ligamentisation. The knee functional status was evaluated at 3 and 12 post-operative months, using the scoring systems (Cincinnati score, IKDC score). RESULTS Bone swelling was found at 3 post-operative months in 18 of 20 patients in both the PRP and the control group. Graft signal intensity was increased in most patients (19 of the PRP group; 18 control patients; p = 0.949). The Cincinnati score at 3 months had an average value of 72.7 (34-100; SO, 18.7) in the PRP group and 73.4 (42-99; SO, 16.3) in the control group (p = 0.793). The functional score after 12 months improved to 97.5 (75-100; SO, 12.8) in the PRP group and to 95.1 (66-100; SO, 13.1) in the control group; there was no significant difference between the groups (p = 0.885) at either 3 or 12 months. The IKDC score showed similar results. At 12 months bone swelling was recorded in seven out of 20 patients in the PRP group and in nine patients in the control group (p = 0.751). Graft signal intensity was increased in three and four patients of the PRP and control groups, respectively (p = 0.681). There was a statistical difference between the findings at 3 and 12 months within each group, but no difference between the groups. DISCUSSION In ACL reconstruction, the process of tendon graft-to-bone healing has several stages involving inflammation, cell proliferation and graft ligamentisation. At each stage, an important role is played by growth factors produced by thrombocytes, and therefore their potential use in the treatment of injuries to ligaments and tendons has recently come into focus. A number of experimental studies dealing with the effect of platelet-rich plasma on soft tissue healing has been published. Therefore, the method of using PRP to enhance graft healing in ACL reconstruction in humans is still being studied. CONSLUSIONS The use of PRP in ACL reconstruction does not accelerate graft remodelling and bone ingrowth into the tendon. The function scoring results showed a statistically significant improvement in knee function between 3 and 12 months of followup within each group studied but revealed no difference between the groups. The hypothesis postulated above was disproved. Key words: anterior cruciate ligament, platelet-rich plasma, anatomic single-bundle reconstruction.