Medial patellar luxation (MPL) and cranial cruciate ligament (CCL) ruptures are common clinical conditions that can occur simultaneously in large dogs and are frequently repaired by individual procedures. The tibial plateau-leveling osteotomy procedure (TPLO) for CCL ruptures preserves the tibial crest by allowing a curved cut of the tibial plateau; however, an additional osteotomy is required if tibial crest transposition is performed, which can decrease stability and cause tibial crest avulsion. This study presented a novel surgical procedure that included TPLO and femoral trochleoplasty; it involved displacement of the osteotomized tibial plateau in relation to the principal tibial fragment during TPLO, resulting in alignment of the quadriceps mechanism and replication of the action of the tibial crest transposition. The study evaluated the efficacy of this combined procedure. Twelve large dogs with MPL and CCL ruptures were included in the study; dogs presented to the veterinary clinic between January 2001 and December 2006. Dogs underwent TPLO and femoral trochleoplasty procedures, resulting in a mean postoperative tibial plateau slope of 8.1 degrees. Surgery was successful in most cases, although additional procedures were necessary in 2 cases. The severity of lameness decreased from preoperative assessment (score, 3.5/5) to measurements obtained 8 to 12 weeks after surgery (score, 0.7/5) and at final follow-up (score, 0.3/5; median, 1115 days). There was no postoperative evidence of patellar luxation in any patients. This novel combination procedure was successful for the simultaneous repair of MPL and CCL ruptures through the alteration of the principal and tibial plateau fragments in this canine population.
Commentary: Medial patellar luxation (MPL) and cranial cruciate ligament rupture (CCLR) often develop concurrently in large and small breeds alike. The simultaneous correction of these conditions in large-breed dogs has posed a unique challenge to the orthopedic surgeon. This article provides a solution that requires only relatively minor adjustments to the already widely accepted TPLO procedure. Keep in mind that large-breed dogs with MPL must be screened for varus deformity of their distal femur, which in many cases must be corrected to help prevent reluxation after surgery. In general, all dogs should be screened for other unique angular and torsional deformities so that the correct procedure can be chosen.
Management of concurrent patellar luxation and cranial cruciate ligament rupture using modified tibial plateau leveling. Langenbach A, Marcellin-Little DJ. J SMALL ANIM PRACT 51:97-103, 2010.