Calcium phosphate-hybridised tendon graft to reduce bone-tunnel enlargement after ACL reconstruction in goats

SummaryBone-tunnel enlargement can have a negative impact on long-term clinical success. To solve the problem, we developed a novel technique to improve tendon-bone healing by hybridising calcium phosphate (CaP) with a tendon graft using an alternate soaking process. The objective of this study was to analyse bone-tunnel enlargement, mechanical properties and histological features, especially the number of osteoclasts at the tendon-bone interface using a CaP-hybridised tendon graft and an untreated tendon graft 6 months after anterior cruciate ligament (ACL) reconstruction in goats. The percentage of bone-tunnel enlargement for the CaP group was decreased compared with that for the control group for the femoral side (p < 0.05). The failure load was not statistically different between the CaP group and the control group, and was all midsubstance rupture for both groups. In the CaP group, cartilage layer was more observed at the tendon-bone interface of the joint aperture site than in the control group (p < 0.05). Many osteoclasts on the femoral side of the tendon-bone interface in the control were observed compared with that in the CaP group (p < 0.05). At the femoral side, the CaP-hybridised tendon graft reduced bone-tunnel enlargement associated with tendon-bone healing 6 months after ACL reconstruction in goats. Clinically, the CaP-hybridised tendon graft for ACL reconstruction can reduce bone-tunnel enlargement.