Effect of calcanean bone-tunnel orientation for teno-osseous repair in a canine common calcanean tendon avulsion model

Abstract

Objective: To determine the influence of bone-tunnel anchoring technique on teno-osseous repair of the common calcanean tendon (CCT) in dogs. Study design: Randomized, ex vivo, biomechanical. Population: Forty-two skeletally mature canine hindlimbs. Methods: Canine hindlimbs were dissected to produce a model simulating avulsion of the CCT and accessory tendons from the calcaneus. Hindlimbs were randomized to 1 of 3 anchoring techniques (n = 14/group): a single transverse tunnel (TT), vertical tunnels (VT), or modified bone tunnels (MT) for teno-osseous repair in a 3-loop-pulley (3LP) pattern using 0 USP polypropylene. Yield, peak and failure loads, construct stiffness, loads to produce a 3 mm teno-osseous gap, and failure modes were compared between groups. Results: The only difference detected consisted of TT constructs yielding at loads 25% higher than MT constructs (P =.027). Conclusion: Although yield loads were lower in MT constructs than other groups, the bone-tunnel anchoring techniques tested here did not appear to influence the biomechanical properties or gapping characteristics of teno-osseous repairs in this canine CCT avulsion model. Clinical significance: All drilling techniques and bone-tunnel orientations tested in the study reported here offer viable options to reattach the CCT to the calcaneus. Surgeons should evaluate how bone-tunnel orientation may affect placement of adjunctive fixation methods to stabilize the talocrural joint after primary CCT repair in dogs.