More severe complications, including tibial crest fracture, fixation failure, and patellar desmitis, are typically associated
with a sudden and sustained increase in lameness and discomfort. Tibial crest fracture is fostered by the tension of the patellar
ligament on the tibial tubercle that is unsupported caudally because of the rotation of the tibial plateau. This complication
is rare when the osteotomy and the temporary Kirschner wire are properly placed and appropriate methods of tibial plateau
rotation are used. However, the risk of tibial crest fracture appears to increase when the osteotomy is shifted too far cranially,
when the tibial plateau is rotated excessively, when a gap is left between the rotated tibial plateau and the tibial crest,
and when the temporary Kirschner wire is placed through the tibial crest distal to the insertion of the patellar tendon.
Failure of the plate fixation of the osteotomy may be the result of catastrophic loading of the limb in excess of the fixation
strength or repetitive low-energy loading contributing to fatigue failure of the implants or implant loosening. Improper orientation
of the osteotomy may increase the relative loading on the implants (less loading borne by the bone segments). Likewise, iatrogenic
fracture of the fibula during a TPLO likely increases mechanical demand on the implants, thereby increasing the risk of failure.
Osteomyelitis is often associated with increased lameness and the development of a draining tract or incisional drainage.
Bacterial culture and antimicrobial sensitivity testing of fluids obtained by deep surgical site aspiration are used to select
appropriate antimicrobial therapy. Once osteotomy healing is documented, implant removal (and repeat culture of the implant
bed) may be indicated.
Cranial cruciate ligament pathology is a frequent cause of lameness in dogs, and surgical stabilization is the recommended
treatment for most of these patients. While many surgical options exist, it is clear that TPLO is the preference of many surgeons
for most patients. Early diagnosis, accurate radiographic measurement of tibial plateau angles, and surgical precision are
key to achieving the desired functional outcome for each patient. It is hoped that the insights offered through this discussion
will help your contributions toward your patients' recoveries.
Ross H. Palmer, DVM, MS, DACVS
Department of Clinical Sciences
College of Veterinary Medicine and Biomedical Sciences
Colorado State University
Fort Collins, CO 80523
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