Articular sagittal and medial parasagittal patellar fracture repair using lag screws in two mature horses

This report describes the clinical experience with internal fixation of a sagittal and a medial parasagittal patellar fracture using lag screws. Severely displaced sagittal and medial parasagittal fractures of the patella were diagnosed in 2 horses (a 10‐year‐old Thoroughbred gelding and a 5‐year‐old Thoroughbred mare) and were repaired using internal fixation. A direct approach through the fascia latae was used. In both cases, the leg was placed in full extension and the fracture was corrected by a combination of digital manipulation and application of bone reduction forceps. Articular congruency was assured by arthrotomy and digital assessment, and radiographic skyline projection. Then, the leg was placed in flexion and two 5.5 mm cortical screws with washers were inserted in lag fashion, under radiographic guidance (skyline projection). In one case, an additional 6.5 mm cancellous screw was used. Both fractures healed without evidence of degenerative joint disease. However, the first horse's wound dehisced, then healed by second intention uneventfully. The second horse was put in a sling in order to prevent lying down. Both horses were able to be used for their intended purpose. In these clinical cases, sagittal and medial parasagittal patellar fractures were treated successfully by open reduction and internal fixation. Post‐operative management in a sling was used successfully in the second case to prevent wound dehiscence.