Extracorporeal Shock Wave Improves Tendon-bone Healing After Reconstruction Of The Anterior Cruciate Ligament: An Experimental Study In Rabbits

[Objective] To explore the effects of extracorporeal shock waves therapy on tendon-bone healing after reconstruction of the anterior cruciate ligament. [Method] Animal model of reconstruction of the anterior cruciate ligament in 18 healthy F/M New Zealand White rabbits (2-3 months old) were established using digital long extensor tendon and randomly classified into 2 groups. The ESW group was given extracorporeal shock waves therapy on 24 hours after reconstruction of the anterior cruciate ligament while the control group was only reconstruction of the anterior cruciate ligament(received no extracorporeal shock waves therapy),All animals were sacrificed respectively at 2,4,8 weeks after operation for histological examinations. The specimens were stained with hematoxylin-eosin and Masson trichrome to investigate pathology change of the tendon-bone healing tissue. The ink intravascular injection was used to observe the neo-vascularization of tendon-bone healing tissue. [Result] The histological examination revealed that at 4 weeks after operation, the ESW group, tendon-bone interface was filled with proliferated fibroblasts and chondroblasts, the collagen fibers was obviously increased and regularly arranged. At 8 weeks after operation, the healing tissue at the bone-tendon interface had developed into dense connective tissue, the collagen fibers was formed in abundance and the perpendicular collagen fibers was regularly and longitudinally arranged. The transition zones of collagen fibers, fibrocartilage and bone (the structure alike a direct ligamentous insertion) occurred in the local region of tendon-bone interface. The histological observations showed that the tissue healing at tendon-bone interface of the ESW group was quicker than those of the control group. The proportion of neo-vessels at the tendon-bone interface of the ESW group was significantly higher than those of the control group at 4 and 8 weeks after operation(respectively p=0.028,p=0.008). [Conclusion] Extracorporeal shock wave treatment can significantly improve the tendon-bone healing after reconstruction of the anterior cruciate ligament in rabbits...