Proximal Ulnar Osteotomy as a Treatment for Humeral Intracondylar Fissure in a Shetland Sheepdog

SIMPLE SUMMARY: Humeral intracondylar fissure (HIF) is a common orthopaedic disease affecting Spaniel breed dogs. Surgical treatment traditionally involved placement of a large transcondylar screw to avoid catastrophic consequences such as a fracture. The reported complication rate related to placement of a transcondylar screw is high and varies between 8 and 59.5%. A recent study describing a cartilaginous lesion present on the caudal aspect of the humerus of spaniel breed dogs with HIF has suggested that humero-anconeal incongruency may be the cause of this abnormal cyclical loading that subsequently leads to stress fracture formation. Theoretically, healing of the HIF could therefore be achieved by performing a proximal ulnar osteotomy and therefore interrupting the abnormal, cyclical loading applied by the anconeal process on the humeral condyle. The purpose of this report is to describe the first case of humeral intracondylar fissure in a Shetland sheepdog and to test our hypothesis that proximal ulnar osteotomy can promote healing of the humeral intracondylar fissure. ABSTRACT: A seven-month-old male Shetland Sheepdog was presented for assessment of thoracic limb lameness of 3 weeks duration. Orthopaedic examination revealed severe discomfort in elbow extension, bilaterally. CT-scan confirmed presence of a complete humeral intracondylar fissure (HIF), bilaterally, and arthroscopic examination of both elbows confirmed the presence of the cartilaginous lesion previously reported in dogs suffering from HIF. A staged oblique proximal ulnar osteotomy was performed to address the humero-anconeal incongruency believed to be the cause of HIF formation. Orthopaedic examination performed 5 weeks after each surgical procedure confirmed that pain previously present on elbow manipulation had subsided. Follow-up examination performed 8 months after the second surgery revealed the dog to be sound at walking on the thoracic limbs with no discomfort present on elbow manipulation. Repeated CT scan confirmed complete healing of both HIFs. This is the first report documenting the presence of HIF in a Shetland sheepdog and complete healing of both HIFs following a proximal ulnar osteotomy.