Effect of Early and Delayed Mechanical Loading on Tendon-to-Bone Healing After Anterior Cruciate Ligament Reconstruction

Abstract

Background: Modulation of the mechanical environment may profoundly affect the healing tendon graft-bone interface.

Effect of Immediate and Delayed High-Strain Loading on Tendon-to-Bone Healing After Anterior Cruciate Ligament Reconstruction

“…However, neither group had significantly improved biomechanical or microstructural properties compared with the prolonged-immobilization group. While previous studies in our laboratory showed that the biomechanical properties of tendon-to-bone healing were better after delayed application of 2% axial strain than they were in the immediate-loading and immobilized groups 14 , the increase to 10% axial strain in the present study did not yield similar results. This suggests that the beneficial effects of delayed loading after a brief period of immobilization may have been offset by the detrimental effects of excessive graft-strain levels.…”

“…Seventy male Sprague-Dawley rats (weight range, 300 to 380 g; age, less than three months) underwent ACL reconstruction with a flexor digitorum longus autograft 14,16 . The knees were immobilized with an external fixator.…”

“…Although many factors contribute to the long-term outcome of ACL reconstruction, secure tendon-to-bone healing is required for a functional graft 4,6 . There is growing evidence that modulation of the mechanical environment has a critical effect on the healing graft attachment site and its ultimate mechanical integrity [11][12][13][14] . In previous animal studies, our group demonstrated that the delayed onset of low levels of controlled mechanical stimulation (;2% cyclic axial strain) resulted in improved mechanical and biological parameters of tendon-to-bone healing compared with those found after immediate loading or strict immobilization 14 .…”

“…There is growing evidence that modulation of the mechanical environment has a critical effect on the healing graft attachment site and its ultimate mechanical integrity [11][12][13][14] . In previous animal studies, our group demonstrated that the delayed onset of low levels of controlled mechanical stimulation (;2% cyclic axial strain) resulted in improved mechanical and biological parameters of tendon-to-bone healing compared with those found after immediate loading or strict immobilization 14 . However, the magnitude of mechanical stimulation required for optimal healing of the tendon-bone insertion site is currently undefined.…”

Cationised gelatin and hyaluronic acid coating enhances polyethylene terephthalate artificial ligament graft osseointegration in porcine bone tunnels

“…During this process, mechanical and biological factors are involved in the healing process of the reconstructed tendons [25][26][27][28][29]. In the distal part of the bone tunnel, the mechanical effect was relatively low and the graft-bone healing was influenced mainly by the biological environment.…”