Gross and histomorphological observations following homologous deep frozen tendon grafting in equines

Abstract

Summary Experimental tenectomies were performed in the mid metacarpal region of the superficial digital flexor (SDF) tendon while the deep digital flexor (DDF) tendon was traumatized in 10 donkeys. In group I (n=8) the deep frozen tendons were used for grafting where as in group II (n=2) no grafting was done. Amniotic membrane casing was performed around grafted SDF and traumatized DDF tendons in group I only. Gross and histomorphological observations were recorded on the last day of the experiment, i.e., on the 15th (n=1), 30th (n=2), 60th (n=2), 90th (n=2) and 120th (n=1), post-operative days (POD) in group I and on the 60th (n=1) and 120th (n=1) POD in group II. Gross intraoperative observations suggested the presence of only thin filamentous adhesions in all but three animals at 30 (two animals) and 60 (one animal) days which were present only in the limited area of grafted tendon as compared to tenectomized SDF tendon that showed thick fibrous adhesion and thickening at both the cut ends. However, DDF tendon showed no adhesions in all except one animal of group I as compared to group II where adhesions were noticed in both the animals. Histological examination suggested an increase in fibroblastic activity at 2 weeks after grafting. Extrinsic and intrinsic healing response was observed in grafted tendons. Inflammatory reaction was reabsorbed by one month. The bundle formation was observed from two to three months. The histological structure appeared near normal by 4 months. Observation suggested that homologous tendon grafts remain viable by all histological criteria and healing was at a comparatively more advanced stage than tenectomized tendon. However, the traumatized DDF tendon healed completely by two months. It is concluded that the tendon healing was more rapid in animals where deep frozen grafts had been used.