Traumatic Patellar Fractures in Cats

Patellar fractures in cats are uncommon. The authors solicited cases of feline patellar fractures from veterinarians via a letter in The Veterinary Record. A total of 55 cases were collected and allocated to 1 of 3 groups: group I, stress fractures (n = 34); group II, fractures considered to be chronic nonunions (n = 10); and group III, traumatic fractures (n = 11). This report described group III cats. Fractures were considered traumatic if there was an observed incident, a concurrent acute fracture or ligament rupture occurred, or there was an open wound over the stifle or the fracture fragments were polar. Six of the cats were male and 4 were female, with a median age of 4.5 years. All fractures were unilateral and onset of lameness was acute. Three cats had concurrent fractures of other bones, 1 had gunshot wounds, 3 had cruciate ligament ruptures, and 4 had patellar luxations (3 medial and 1 lateral). Ten cats had surgical interventions and 1 cat was treated conservatively. Surgical repair involved removal of smaller fragments of the patella, correction of soft tissue injuries, and/or use of pins and wires. The outcome was considered good or normal in 6 cats, 3 cats were “improving” or had intermittent lameness, and the outcome was unknown in 2 cats.

COMMENTARY: This case series nicely describes the various configurations of traumatic patellar fractures in cats, as well as some of the potential concurrent injuries, such as cranial cruciate ligament tears and patella luxation, that frequently accompany these fractures. For the practicing clinician, it can be difficult to determine what component of the clinically seen lameness or pain is caused by each injury. As a result, we frequently treat what we can and wait to see how the patient responds. Although this study is somewhat limited in scope and follow-up by its retrospective nature, it does suggest that a good, functional outcome can be achieved in cases of feline patellar fracture despite the articular nature of these injuries.—Kelson Danielson, DVM

Traumatic fracture of the patella in 11 cats. Langley-Hobbs SJ, Brown G, Matis U. VET COMP ORTHOP TRAUMATOL 21:427-433, 2008.