An Experimental Study On The 95% Ethanol Immersed Allogenous Vascularized Tendon Graft

Objective To investigate the effect of 95 % ethanol immersion processing on tendon healing in allogenous tendon grafting as to provide more clinical evidence for curing long tendon defect by using allogenous tendon.Methods 48 adult chickens were randomly divided into 3 groups. In 95% ethanol immersed allogenous tendon group, the third M. flexer digitorum profundus were harvested and immersed in 95% ethanol before being grafted to the defect Achilles tendons site. In the fresh allogenous tendon group, the fresh allogenous tendon was grafted to the defect Achilles tendons site. The autogenous tendon group, tendons were interposed at the defect sites as control group. All of the graft operations were conducted by the way of modified Kessler Method. After the operation, the site was binded up to a total flection position by a boxing mitten shape respectively. Function exercises were practiced as well by gradually increases the flection extent and frequency. The morphological and histological changes were observed at 2,3,4,6 and 8 weeks postoperatively. Tensile strength tests were carried out whichincluding tendon sleek distance measurement. Tendon healing, conglutination and function were assessed by mimic TAM grade. Tensile strength tests were carried out at 8 weeks postoperatively.Results 95% Ethanol processing of the allogenous tendons were well established and healing was as well. We observed tendon continuity, tendon cells, collagen fibers array, as well as collagen fibers diameter from general view and HE stained slices, we found that the ethanol processed group healed completely, the fibreblasting cell infiltrated into the allogenous tendon cells after 6 weeks without any differences with the autogenous tendon group, which was much' more better than allogenous group with similar normal tendon structure and peripheral fibreblasting cell hyperplasia. The ethanol processed group healed well. The TAM grade (63.7) of the ethanol processed group was higher than the allogenous group but lower than autogenous group ( 80. 0 ) , which is used to evaluate the tendon flection function and indicate that the ethanol processed group may lost some mobile function because of tendon conglutination. The ethanol-processed group is similar with aotogenous group and better than allogenous group in tendon dynamic test. By statistics analysis, no differences were found in tensile strength tests between the ethanol processed group (48. 3+.3.9N) and the autogenous group (50. 1 + 3. 4N) (p>0.05). The average tensile strength of the allogenous group (33.7 + 4. 2N) was lower than the ethanol processed group(p<0.05) .Conclusion The experiment indicate that 95% Ethanol processing of the allogenous tendons can be well established with host allogenous chicken tendon, which is practical for chicken allogenous tendon defect. It is much better than direct allogenous chicken graft. Meanwhile, the allogenous tendons can reduce their antigenicity but destroyed the tendon cell structure, which enhanced the graft-host tissue reaction, partly exogenous infusion and lead to inevitable tough conglutination. Anyway, 95% Ethanol processing of the allogenous tendons can be easily prepared, stored and have a satifactionary healing effect;it is an ideal option for long tendon graft.