Patellar Luxation

Patella luxations occur frequently in dogs (primarily medial (MPL) [1]) and less commonly in cats [2]. It is normally seen in small breed dogs but is becoming more common in dogs such as the Labrador retriever. It can be unilateral or bilateral (50-65%) of cases. Both conservative and surgical methods are used for correction of patella luxation and this decision-making usually depends on the severity of the luxation (grade> 2 usually requiring surgical correction). Surgical correction of the luxation has a very high failure rate with up to 48% of cases having recurrent luxation of the patella reported in one study (although concurrent lameness was not observed [3]). A more recent study reports overall complication rates of 18% and a reluxation rate of 8% [4]. It is not clear why this failure rate is so high but failure to correct the underlying abnormalities (i.e. decision making errors rather than technical ones) is a likely cause.