The aim of this study was to report patellar groove replacement in a 6-year-old domestic short hair cat with chronic unilateral pelvic limb lameness and severe femoro-patellar osteoarthritis due to medial patellar luxation. This study is a case report. Computed tomographic scan of the affected limb revealed marked periarticular osteophytosis, medial trochlear ridge erosion, marked flattening of femoral trochlea, ectopic pseudo-trochlear groove, and medial patellar luxation. Femoral trochlear ostectomy with patellar groove replacement, release of the medial fibrocartilage, partial parasagittal patellectomy, and lateral tibial tuberosity were performed. Clinical review and radiographs performed 53 days post-surgery revealed no complications and substantial decrease in lameness. Thirteen months postoperatively the cat scored 2/72 on the Feline Musculoskeletal Pain Index questionnaire by the owner, indicating good mobility, minimal discomfort, and good quality of life. As far as the authors are aware, this is the first report of the use of patellar groove replacement in the management of feline medial patellar luxation. Patellar groove replacement, in combination with adjunctive procedures, resulted in a substantial improvement in lameness in this cat with chronic medial patellar luxation and severe femoro-patellar osteoarthritis.

Case summary An Oriental Shorthair cat, aged 1 year and 6 months, developed progressive stridor and a palpable right ventral cervical mass. Fine-needle aspiration of the mass was inconclusive, while thoracic radiography and CT showed no evidence of metastasis. There was initial improvement in stridor with oral doxycycline and prednisolone treatment, but it recurred 4 weeks later and excisional biopsy was performed. Histopathology with immunohistochemistry diagnosed leiomyosarcoma with incomplete surgical margins. Adjunctive radiation therapy was declined. Repeated physical examination and CT 7 months postoperatively documented no evidence of mass recurrence. Relevance and novel information This is the first reported case of retropharyngeal leiomyosarcoma in a young cat with no evidence of local reoccurrence 7 months following an excisional biopsy.