Effects of demineralized bone matrix on tendon-bone healing in an intra-articular rodent model.

Abstract

Techniques to improve and accelerate tendon-bone healing could be advantageous in anterior cruciate ligament (ACL) reconstruction. Effects of demineralized bone matrix (DBM) on intra-articular tendon-bone healing have not been examined. Demineralized bone matrix has the potential to convey osteoinductive growth proteins to the site of healing at the tendon-bone interface. We hypothesized that the presence of DBM will result in more bone formation and hasten tendon-bone healing. Controlled laboratory study. Fifty-six female athymic rnu/rnu (nude) rats were used. Rats were randomly allocated into 2 groups (control or treatment). The control group underwent an ACL reconstruction, while the treatment group had human DBM implanted in the tendon graft and bone tunnel before reconstruction. Rats were sacrificed at 2 (n = 8), 4 (n = 24), and 6 (n = 24) weeks for histological, and immunohistochemical (t = 2, 4, and 6 weeks), and biomechanical testing and micro-computed tomography (t = 4 and 6 weeks) end points. Our findings suggest that in the presence of DBM, tendon-bone healing is augmented by increased woven bone formation and enhanced bone remodeling as indicated by histology and micro-computed tomography. This ultimately resulted in a statistically significant increase in peak load to failure of the tendon-bone interface at 4 weeks (DBM group: 5.96 ± 1.36 N; control group: 2.86 ± 0.7 N) and 6 weeks (DBM group: 9.13 ± 0.97 N; control group: 5.81 ± 1.1 N). Demineralized bone matrix at the tendon-bone interface promotes healing between the tendon and bone in a rodent ACL model. Introduction of osteoinductive DBM at the tendon-bone interface during ACL reconstructive surgery may improve short-term outcomes.