The Effect Of Tendon-bone Healing Of Tendon Graft Anterior Cruciate Ligament Reconstruction By Platlet-rich Plasma

Part I A study of the use of the platlet-rich plasma to effect tendon-bone healing: in a rabbit of tendon autograftPurpose The success of tendon-bone junction using autografts depends on biological integration between the tendon to bone. Platlet-rich plasma(PRP) contain a large number of growth factors, and growth factors play a significant role in this integration process. We hypothesized that injected to tendon-bone interface may enhance the healing of tendon graft in a bone tunnel. Methods The study was performed on twelve healthy, skeletally mature New Zealand White rabbits. Each rabbit underwent bilateral extra-articular tendon transfer surgery that to stimulate tendon to bone junction. PRP gel was injected into the bone tunnel in one limb, and the contralateral limb served as a control. Histological investigations were performed at 2,4,and 8 weeks after surgery. Healing between the tendon and bone tunnel was assessed morphologically by determining the presence of fibrovascular tissue and collagen fibers.Results In the control specimens, the fibrovascular tissue at the bone-tendon interface had developed into dense connective tissue with poor vascularization. In the treated specimens, the bone tunnel had more areas of denser connective-tissue ingrowth. The interface tissue was more mature and contained numerous perpendicular collagen bundles (Sharpey fibers) and fibrocartilage to appear. Conclusions The present study demonstrated that PRP can enhance bone-tendon healing. The use of PRP gel is a novel method offering the potential of more physiologically earlier healing. Part II Tendon-bone healing enhancement using platelet-rich plasma in a rabbit anterior cruciate ligament allograft reconstruction modelPurpose This study was conducted to analyze the effect of coating allografts with PRP gel on the quality and rate of osteointegration at the allograft tendon and bone interface, and the biomechanical properties of these enhanced anterior cruciate ligament (ACL) grafts compared with controls. Methods Bilateral ACL reconstructions using Achilles tendon allografts were performed in 24 rabbits. On 1 limb, the allograft was performed PRP gel pretreatment, while the contralateral limb served as a control with no PRP. The reconstructions were assessed histologically and biomechanically at 2,6 and 12 weeks. Results At 12 weeks, histologic analysis of the controls revealed the development of mature scar tissue resembling Sharpey fibers spanning the tendon-bone interface. In contrast, the PRP pretreatment reconstructions showed a mature zone of fibrocartilage blending from bone to the allograft, strongly resembling a normal ACL insertion. On biomechanical testing, the treated grafts had significantly higher load-to-failure rates than controls. However, the stiffness and Young's modulus were lower in the treatment group. Conclusions The application of PRP at the allograft tendon-bone interface during ACL reconstruction results in the development of an intervening zone of fibrocartilage. The use of PRP to enhance allograft osteointegration is a novel method offering the potential of more physiologic and earlier healing, although further investigation must be conducted to improve the biomechanical strength.