Homologous plasma-stored tendon grafting in equids--gross and histomorphological observations

The efficacy of homologous plasma-stored tendon grafting in the superficial digital flexor tendon severed in the mid-metacarpal region was evaluated in 10 donkeys. Experimental tenectomies were performed, followed by grafting using plasma-stored tendon and human amniotic membrane encasement in group I (n=8) but no grafting or encasement in group II (control) (n=2). Gross observations in group I showed no peritendinous adhesions, except in one animal, while control animals showed thick fibrous adhesions and thickening at both the cut ends. Histologically, in the grafted tendon there was normal healing tissue at the junctional sites with negligible collagen fibre and mild regressing inflammatory reaction by day 15. By day 30 there were a great number of blood vessels but without any inflammatory reaction. The healing tissue at the grafted site and the adjoining paratenon was more mature. The fibroblastic activity appeared to be both extrinsic and intrinsic in origin. By day 60 fibroblastic activity was negligible and the healing tissue at the distal graft and host tendon junction site was at a more advanced stage of maturation and showed early fasciculi/bundle formation. Healing tissue at three months showed collagen fibres fasciculi/bundle comparable to normal tendon architecture. Tendon appeared histologically normal at four months after grafting.