Treatment of subchondral cystic lesions of the medial femoral condyle of mature horses with growth factor enhanced chondrocyte grafts: a retrospective study of 49 cases

Reasons for performing study: To evaluate the long‐term clinical outcome after allogeneic chondrocyte and insulin‐like growth factor‐I (IGF‐I) grafting of subchondral cystic lesions (SCLs) of the femoral condyle in horses. Objective: To test the hypothesis that chondrocyte and IGF‐I grafts will improve the long‐term clinical outcome in arthroscopically debrided SCLs. Methods: Medical records of 49 horses with SCLs of the femoral condyle treated by debridement and implantation of chondrocytes and IGF‐I were reviewed. Preoperative radiographs were obtained, and caudocranial radiographic projections were used to establish a ratio between cyst and femoral condyle size. Arthroscopic cyst debridement followed by filling of the bone void with autologous cancellous bone (45 horses) or tricalcium phosphate granules (4 horses) was performed. A paired syringe containing a fibrinogen and chondrocyte mixture in one syringe and calcium‐activated bovine thrombin with IGF‐I in the other was used to cover the surface. A successful outcome was defined as a horse that performed to its intended use without lameness. Results: A successful outcome was achieved in 36 of 49 horses (74%). Preoperative radiography was performed in all horses, with 33 horses having unilateral SCLs of the medial femoral condyle, 15 horses having bilateral SCLs of the medial femoral condyle, and one horse having bilateral SCLs of the lateral femoral condyle. Median age of the horses was 3.3 years. Fifteen horses had preoperative radiographic and arthroscopic evidence of osteoarthritis (OA). A successful outcome was not influenced by age of horse, presence of pre‐existing osteoarthritis or preoperative size of the subchondral cyst. Grafting resulted in success for 80% of horses >3 years old, and in 80% of horses with OA. Conclusions: Implantation of allogeneic chondrocytes supplemented with IGF‐I is an effective treatment for horses with SCLs of the femoral condyle, and particularly for older horses and horses with pre‐existing osteoarthritis. Potential relevance: Chondrocyte implantation may offer a greater chance of long‐term success in older horses and horses with osteoarthritis than has been previously reported with cyst debridement alone.     

Bilateral Sertoli and Interstitial Cell Tumours in Abdominal Testes of a Goat with Polled Intersex Syndrome (PIS)

An 8‐year‐old, mixed breed, polled goat was presented for evaluation of male‐like behaviour. Clinical findings included clitoromegaly, a heavily muscled neck, pronounced beard, and erect dorsal guard hairs, which are phenotypic characteristics commonly observed in intersex animals. Transrectal ultrasonography revealed the presence of two abdominal masses caudolateral to the uterine horns. Serum concentration of estradiol was elevated. Genetic evaluation was compatible with polled intersex syndrome defined by an XX karyotype without a Y chromosome or SRY gene. Based on gross and histologic evaluation, the abdominal masses were determined to be intra‐abdominal testes, each of which was effaced by Sertoli cell and interstitial (Leydig) cell tumours. The Sertoli cell tumours (SCTs) represented two unique histologic patterns. Regardless of pattern, neoplastic Sertoli cells were consistently lipid laden and positive for vimentin. Interstitial cell tumours (ICTs) were negative for vimentin. Clinical and histopathologic findings suggest that prolonged exposure to steroids secreted by neoplastic Sertoli cells contributed to virilization. In addition, results from immunohistochemistry indicated that vimentin may be a valuable immunodiagnostic tool for differentiation between interstitial and Sertoli cell tumours in goats.     

Bilateral parotid duct transposition for keratoconjunctivitis sicca in a Connemara stallion

A 7‐year‐old Connemara stallion was presented with a 4 month history of blepharospasm, recurrent corneal ulcerations, mucopurulent ocular discharge, and keratoconjunctivitis sicca (KCS) in both eyes unresponsive to medical therapy. Ophthalmic examination revealed lackluster corneas, axial corneal scarring and pigmentation with associated neovascularization, and absolute KCS in both eyes. Computed tomography scan and endoscopic evaluation of the upper airway and guttural pouches revealed no structural abnormalities to indicate neurogenic KCS. The stallion was diagnosed with immune‐mediated dacryoadenitis as all other causes of KCS were excluded. Parotid duct transposition (PDT) was performed in the right eye followed by PDT in the left eye 4 weeks later. The right PDT was functional 2 years post‐operatively with significant improvement in ocular comfort and reduced corneal fibrosis and neovascularization. The left PDT developed a salivary‐cutaneous fistula over the left masseter muscle post‐operatively due to avascular necrosis of the distal parotid duct (PD). Surgical reconstruction of the PDT using an expanded‐polytetrafluoroethylene (e‐PTFE) tube graft, an e‐PTFE tube graft to autogenous caudal auricular vein graft, and an autogenous saphenous vein graft were all unsuccessful. Tear production in the left eye improved at 1 year post‐surgery as a result of long term lacrostimulant therapy, and a permanent PD‐cutaneous fistula was performed on the left PD at the level of the ventral mandible. Bilateral PDT in the horse is effective in resolving clinical signs associated with KCS; however, morbidity associated with avascular necrosis of the transposed PD may be significant and can result in surgical failure.