Spontaneous bilateral avulsion fracture of the tuberositas tibiae in a New Zealand White rabbit - a counterpart to Osgood-Schlatter disease in humans?

The first reported case describing a spontaneous bilateral avulsion fracture of the tuberositas tibiae in a New Zealand White rabbit is presented. So far in animals, this condition has been only described in dogs and horses. In humans, this condition is also called Osgood-Schlatter disease (OSD) or syndrome, traction apophysitis of the tibial tubercle (ATT) or patellar tendon enthesopathy of the tibial tuberosity respectively. It is mainly seen in young adolescents coinciding with periods of growth spurts. In humans, its pathogenesis is believed to be caused by repetitive tendon/muscle strain at the insertion of the patellar tendon to the immature tibial tuberosity, which has its own secondary ossification center. Morphologically this case is characterized by bilateral chronic avulsion with incomplete separation of the tuberositas tibae, and proximal dislocation of the patella (patella alta). Despite these marked pathological changes, the animal was clinically without findings. Nevertheless, this case emphasizes the need for thorough clinical and radiological examination of rabbits intended for preclinical research studies prior to study begin, especially in orthopedic research.