A nine-month-old male castrated Yorkshire Terrier presented to Cornell University Hospital for Animals (CUHA) Orthopedic Surgery Service for a chief complaint of lifelong hind limb deformities and gait abnormalities. Clinical signs included a kyphotic posture, inward rotation of the hind limbs, stifles held in extension with decreased range of motion and pain on extension, minimal weight bearing of the hind limbs, and outward rotation of the elbows bilaterally. Orthopedic exam revealed grade IV/IV bilateral medial patellar luxation with secondary muscle contracture and bone remodeling. Computed tomography scan showed severe hyperflexion of the stifle joints, medial displacement of the patellae, flat femoral trochleae, lateral rotation of the distal femurs, medial rotation of the tibias and fibulae, and marked internal rotation of the pes. The diagnosis was determined to be severe, bilateral, medial patellar luxation, with subsequent bilateral, severe, angular limb deformity. Treatment options entailed surgical correction and post-operative physical therapy. The surgical plan included arthrotomy to assess the integrity of the cranial cruciate ligaments, medial fascial release, block trochleoplasty, and corrective osteotomies of the distal femurs and mid-diaphyseal tibias and fibulae. Due to financial constraints surgery was not performed.

This seminar will review the presentation, diagnosis, and treatment of medial patellar luxation.