Diagnosis and surgical correction of congenital bilateral patellar luxation in two dwarf zebu calves

This case study presents two female dwarf zebu calves with permanent bilateral flexion of the stifle joint secondary to bilateral congenital lateral patellar luxation. The patella could be manually repositioned bilaterally in the first calf (14 days old), but re-luxated immediately with release of manual pressure (luxation grade III). In the second calf (28 days old) both patellae were permanently luxated laterally (grade IV). The right and left stifles of each calf were operated in a staged procedure with approximately 14 days between surgery of the two sides. While a lateral release and a medial imbrication were sufficient for correction in the left stifle of the younger calf, a trochlear wedge resection was required in the other three stifle joints with hypo- to aplastic trochleas in order to stabilize the patella. Postoperatively each stifle was immobilized for 10 days with a cast. The younger calf regained full function of the hind limbs during the complete gait cycle in walk and in trot one month after the procedure. The older calf regained full function in the hind limbs in walk but in trot there was some degree of lameness due to a reduced extension of approximately 20°.