Tibial tuberosity avulsion fracture in dogs: a review of 59 dogs.

OBJECTIVES: To evaluate the high incidence of tibial tuberosity avulsion fracture diagnosed in skeletally immature Staffordshire bull terriers presenting to a UK animal welfare charity hospital. METHODS: A retrospective review of tibial tuberosity avulsion fractures treated by the hospital between 2002 and 2007. RESULTS: Sixty-five tibial tuberosity avulsion fractures were recorded in 59 dogs. Fifty-one tibial tuberosity avulsion fracture-affected dogs (86 per cent) were Staffordshire bull terriers. Dogs sustaining tibial tuberosity avulsion fractures had median and mean ages of five and 4.9 months, respectively (range three to 10 months). Where recorded, injury was associated with a short fall or jump (typically 3 to 4 feet) in 29 of 50 dogs. Three fracture patterns were recorded: 37 stifles sustained isolated tibial tuberosity avulsion fracture; 15 stifles sustained tibial tuberosity avulsion fracture accompanied by separation of the proximal tibial epiphysis; in 13 stifles epiphyseal separation extended to produce Salter-Harris type II fracture of the caudal tibial metaphysis. On analysis of the hospital database, tibial tuberosity avulsion fracture was a reason for presentation in 51 (3.3 per cent) of 1536 Staffordshire bull terriers, but only five (0.18 per cent) of 2815 other breed dogs, registered under the age of 12 months during the study period (P < 0.001). CLINICAL SIGNIFICANCE: Staffordshire bull terriers commonly present with tibial tuberosity avulsion fracture, with or without concurrent separation of the proximal tibial epiphysis, to this urban charity hospital.