For years now, the “go-to” surgery for horses with intermittent upward fixation of the patella (UFP) has been a procedure called medial patellar (knee cap) ligament desmoplasty or ligament “splitting.” But veterinarians at Peterson & Smith Equine Hospital recently determined that desmoplasty isn’t always successful, and not all owners of treated horses are satisfied with the outcome.

“The exact cause of UFP in horses remains unknown, but conformation factors are thought to contribute to its development, such as straight limb conformation, high medial (inner) hoof walls, elongated toes, and weakness of the quadriceps muscles and medial patellar ligament,” explained Maggie D. Peitzmeier, DVM, a surgical resident at the Ocala, Florida-based hospital.

The exact prevalence of UFP is also unknown, largely because many horses are treated conservatively in the field by their primary veterinarians rather than being referred for surgical correction