Bilateral Functional Tarsal Hyperextension Associated with Stifle Pathology Improved Following Stifle Stabilization in a Dog: A Case Report

Abnormal tarsal posture in dogs may be associated with structural lesions such as common calcaneal tendon complex rupture, plantar-supporting structure injury, tarsocrural instability, or neurologic dysfunction; however, common calcaneal tendon rupture is typically associated with a plantigrade posture rather than the weight-bearing-dependent tarsal hyperextension pattern described in this case. A 3-year-old intact male Pomeranian developed bilateral weight-bearing-dependent tarsal hyperextension immediately after bilateral medial patellar luxation (MPL) surgery performed at another hospital. At our hospital, complete cranial cruciate ligament rupture of the right stifle and recurrent grade II MPL of the left stifle were identified. Right lateral fabellotibial suture stabilization using a LigaFiba® 75 lateral suture and crimp system, with supportive reapplication of a 0.8 mm Kirschner wire at the previous tibial tuberosity transposition site, and left trochlear block recession with capsular resection and imbrication were performed. No direct surgical treatment of either tarsus was undertaken. During follow-up after stifle stabilization, bilateral tarsal hyperextension progressively decreased and was no longer clinically observed by 5 months. This case suggests that bilateral weight-bearing-dependent tarsal hyperextension may occur secondary to proximal stifle pathology even in the absence of major structural tarsal instability, and that hyperextension may resolve clinically following stifle stabilization.