Growth dynamics of the canine proximal tibial physis

Abstract

Objective- To determine growth of the proximal tibial physis in the Labrador Retriever, a breed of dog at risk for rupture of the cranial cruciate ligament (RCCL). Animals- 6 male Labrador Retriever dogs Methods- 0.5 mm tantalum markers were implanted in the right proximal tibial epiphysis and metaphysis of each dog at sixteen weeks of age. Lateral and cranio-caudal radiographs of the tibia were made monthly and longitudinal growth was assessed from the radiographs. A growth curve was generated from the data. Data from previous patients that had undergone proximal tibial epiphysiodesis (PTE) was compared to the growth curve to demonstrate if the growth curve accurately predicted changes in growth associated with this procedure. Results- Growth rate decreased slowly and non-linearly over the first year of age. Growth from the proximal tibial physis is described. Conclusions- The growth curve generated here follows the model of saltation and stasis. The growth curve generated here predicted the change in tibial plateau angle (TPA) for two Labrador Retrievers that underwent PTE (+/- 1°). Clinical relevance- The growth curve generated in the present study may be considered for use for the surgical planning of PTE in Labrador Retrievers. Key Words- Proximal tibial epiphysiodesis, growth, saltation and stasis, Labrador Retriever