Ultrasonography of mid-metacarpal region following tendon allografting in equine

Abstract

Serial longitudinal ultrasonographic examination of palmar surface of left mid-metacarpal region was performed before and after tendon allografting of superficial digital flexor (SDF) tendon and traumatizing deep digital flexor (DDF) tendon in donkeys of groups I (n=8),2 (n=8), 3 (n=8) and 4 (n=2). In groups I, 2 and 3 animals deep frozen 4 plasma stored and glycerin preserved tendon allografts were used, respectively, while in group 4 animals after tenectomy no grafting was done. Both grafted SDF and traumatized DDF tendons were encased with amniotic membrane. A sonography score was assigned to tendon architecture and peritendinous adhesions. Serial ultrasonograms of operated limb (left) delineated the presence of anechoic images (edema/hemorrhage) up to average period of 14 days (POD) followed by disappearance of anechoic echotexture and progression of tendon union/healing indicated by hypoechoic bridging between the graft and host tendon. Serial sonograms taken on day 42 in groups 1, 2 and 3 were quite suggestive of the well laid down hypoechoic pattern without any evidence of anechoic region. However, traumatized DDF tendon showed completely normal tendon. architecture by this time. Sonograms on day 56 and 70 in groups 1, 2 and 3 suggested near normal echo-patterns in the grafted SDF tendon with further improvement at day 90 and 120. Ultrasonography proved helpful for assessing the tendon healing process and adhesion formation, tendon continuity and thickening after tendon allografting to SDF tendon and trauma to DDF tendon in equine. No considerable difference could be visualized in the healing pattern between different allografted tendons.