Page 387 - Canine Lameness

20.5 Hip Dysplasia 359

(A) (C) (E)

(B) (D) (F)

Figure 20.7 Coxofemoral luxation: (A, B) traumatic cranio-dorsal luxation; (C, D) traumatic caudo-ventral
luxation; and (E, F) luxation secondary to hip dysplasia. (A) Note the avulsion fragment of the femoral head
(white arrow) – a contraindication for closed reduction. (E) The bilateral nature in combination with the
degenerative changes (the white arrow indicates femoral neck thickening) suggests that this dog is not
suffering from traumatic coxofemoral luxation, but rather severe laxity due to hip dysplasia.

coxofemoral joint without evidence of OA. This laxity allows subluxation of the hip joint to occur, HIP REGION
eventually giving rise to a shallow acetabulum, flattening of the femoral head from wear on the
DAR, and eventually the development of OA of the joint. Treatment for HD most commonly con-
sists of medical management; however, numerous surgical options are available. Early diagnosis of
HD is key since some treatment options, such as juvenile pubic symphysiodesis (JPS), are only
effective if performed before 5 months of age (Schachner and Lopez 2015).

20.5.1 Signalment and History
HD is most commonly seen in large-breed dogs, but can be seen in most breeds, with Sighthounds
being a protected group of dogs. Some more commonly affected breeds include German Shepherd
Dogs, Newfoundlands, Retriever breeds, and Rottweilers with a reported prevalence of up to 17%
(Witsberger et al. 2008). Early gonadectomy (<5 months of age) has been associated with a higher
risk of developing HD (Spain et al. 2004). One study found castrated male dogs to be significantly
more likely to be affected by the disease (Witsberger et al. 2008).
A clinical bimodal presentation – dogs presenting as juveniles (juvenile form) or as middle-aged
dogs (chronic form) – is seen in dogs affected by HD (Demko and McLaughlin 2005; Witsberger
et al. 2008; Smith et al. 2018). However, radiographic progression has been reported to be linear
(Smith et al. 2006). Dogs presenting at a young age generally are more severely affected and have