Biomechanical changes of injured rabbit tendon-to-bone interface during repair with calcium phosphate cement-II / 中国组织工程研究

ABSTRACT

BACKGROUND:Calcium phosphate cement and recombinant human bone morphogenetic protein-2 both have bone osteoinductivity. Maybe both of them could promote repair of tendon-to-bone interface damage. OBJECTIVE:To evaluate the effect of calcium phosphate cement-II containing recombinant human bone morphogenetic protein-2 on tendon-to-bone interface healing after rotator cuff injury . METHODS: Twenty-seven adult healthy rabbits were enroled in the study. The tendon-to-bone interface of the bilateral shoulder joints was taken from three rabbits as normal group, and the bilateral shoulder joints of the other 24 rabbits were subjected to acute rupture of the rotator cuff and tendon-to-bone reconstructive surgery as experimental group (n=12) and control group (n=12). Rabbits in the experimental group were treated with calcium phosphate cement-II, while those in the control group treated with nothing. Specimens were colected at 2, 4, 8 postoperative weeks for biomechanical test. RESULTS AND CONCLUSION:The maximum tensile strength of the rotator cuff in the experimental group was higher than that in the control group (P < 0.001), but lower than that in the normal group (P < 0.001). At postoperative 8 weeks, the rigidity of rotator cuff of the experiment group was higher than the control group (P < 0.001) but lower than the normal group (P < 0.001). These findings indicate that calcium phosphate cement-II can improve the maximum tensile strength and rigidity of rabbit tendon-to-bone interface in the early postoperative period, enhance tendon-to-bone interface binding force, and promote tendon-to-bone interface healing.