Novel Achilles tendon repair technique utilizing an allograft and hybrid external fixator in dogs

Abstract

Background: Achilles mechanism rupture is a surgical condition involving primary tenorrhaphy with various described means of surgical augmentation and bolstering.

Aim: To report complications and outcomes with a novel Achilles repair technique in dogs using a superficial digital flexor tendon (SDFT) or deep digital flexor tendon (DDFT) allograft.

Methods: Medical records were reviewed for dogs with chronic rupture or deterioration of the Achilles mechanism. Fibrous tissue was excised and either primary tenorrhaphy or reattachment of the tendon(s) to the calcaneus was performed. The surgical repair was supplemented by an SDFT or DDFT allograft, and postoperative immobilization was provided using a transarticular hybrid external skeletal fixator. Complications were classified as minor, major, or catastrophic, and function was classified as full, acceptable, or unacceptable, based on established guidelines.

Results: Complications occurred with 6 out of 12 repairs, including 1 minor, 6 major, and 2 catastrophic complications. The two catastrophic complications were the recurrence of tarsal hyperflexion and lameness at 20 weeks and 18 months following surgery. Of the 12 surgeries performed, 2 resulted in full function, 8 with acceptable function, and 2 with unacceptable function at last follow-up 17-98 weeks postsurgery (mean = 45 weeks) for a success rate of 10/12 cases.

Conclusion: The use of SDFT or DDFT allografts, coupled with an external fixator, can provide a moderate rate of full or acceptable functional outcomes and appears a viable treatment. However, complications were frequent and without a comparison group no conclusions can be drawn about the inferiority or superiority of this technique to other techniques for Achilles mechanism repair in dogs.

Keywords: Achilles tendon; Allograft; Common calcaneal tendon; Dog; Transplantation.

Fig. 1.. (A) Gastrocnemius and common tendon severed. (B) Abnormal gastrocnemius and common tendon excision; normal tendon tissue indicated by arrow. (C) Plantar calcaneal notch burred. (D) Double Krackow suture pattern used to reattach gastrocnemius and common tendon through two calcaneal tunnels. (E) SDFT allograft. (F) Allograft sutured to one side and tension applied. (G) Allograft sutured to medial and lateral sides of the native gastrocnemius tendon. Note that additional interrupted sutures were placed to secure the allograft to the native gastrocnemius tendon prior to surgical closure. (H) Hybrid external skeletal fixator (ESF) applied. (I) Postoperative radiograph; the drill tunnels from the proximal tuber to the plantar calcaneal notch are indicated by the arrow and the plantar calcaneal notch is indicated by a triangle.