Surgical management of pivot-shift phenomenon in a dog.

CASE DESCRIPTION A 6.8-year-old neutered male Labrador Retriever-Poodle mix was evaluated because of continued left pelvic limb lameness unresponsive to conservative management 1 year after undergoing tibial plateau leveling osteotomy (TPLO). CLINICAL FINDINGS A jerking lateral movement of the left stifle joint was detected during walking. Orthopedic examination revealed a pivot-shift phenomenon (PSP). Palpation elicited no signs of discomfort over the TPLO plate or caudomedial aspect of the stifle joint. Radiography revealed complete bone fusion at the osteotomy site and only mild joint effusion. TREATMENT AND OUTCOME Arthrotomy was performed at the medial aspect of the stifle joint, revealing no meniscal tears. The previously applied plate was removed, and an extracapsular, synthetic, ligament-like biomaterial was placed to counteract internal tibial rotation, thereby eliminating the PSP. Six weeks later, lameness had improved considerably with no evidence of PSP; 8 weeks after surgery, the dog was assessed for sudden-onset lameness in the right pelvic limb. Cranial cruciate ligament rupture was suspected, and TPLO was performed. The PSP was identified intraoperatively, so an extracapsular implant was placed. Six weeks later, the dog had only mild lameness and no evidence of PSP in either pelvic limb. In a follow-up telephone conversation 1 year later, the owner reported no obvious lameness or gait abnormalities. CLINICAL RELEVANCE Use of an extracapsular implant effectively eliminated the PSP following TPLO in the dog of this report and can be considered as an intra- or postoperative option for dogs with PSP that responds poorly to conservative management.