Jennifer Brisson DVM, DACVR
Massachusetts Veterinary Referral Hospital, Woburn, MA
History
A 2-year-old castrated male Maine Coon cat was presented to the emergency department for evaluation following an acute onset of left hind limb lameness after being spooked and running away from a vacuum cleaner.
Physical exam
- Toe touching lame left hind limb
- Painful on extension and manipulation of coxofemoral joints bilaterally
- Grade II left medial patellar luxation
Orthogonal radiographs of the pelvis/hips and femurs are obtained.
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Findings
Orthogonal radiographs of the pelvis and femurs reveal a minimally displaced capital physeal fracture on the right with slight cranial and dorsal displacement of the femoral diaphysis. The right femoral head maintains a normal shape and position in the acetabulum. On the left, there is a linear lucency associated with the femoral neck. The left femoral head has a normal size and shape and remains within the left acetabulum with mild congruity of the caudal aspect of the coxofemoral joint space.Findings consistent with bilateral capital physeal fractures, secondary to metaphyseal osteopathy.
Discussion
Feline capital physeal dysplasia, or metaphyseal osteopathy, is an intra-articular disorder of the physeal cartilage that results in separation of the femoral head and neck. There are irregular clusters in the organization of the physeal chondrocytes, and the thickness of the affected physis has been reported to be twice that of a normal capital physis.Affected cats are usually less than two years of age, more commonly male, of obese body condition, and with a minimal or no history of trauma (unlike in dogs or humans). The lesion may occur bilaterally. In the acute phase, the femoral head and neck usually maintain a normal size, shape, and opacity. In chronic cases, a non-union can occur with remodeling and osteosclerosis, leading to osteoarthritis of the coxofemoral joint. Affected cats may be treated conservatively, with surgical stabilization, or by femoral head and neck ostectomy.