Surgical Treatments of Patellar Luxation in Dogs

Medial patellar luxation is a condition in which the patella, or kneecap, tends to move towards the inner side of the knee joint. In relatively mild cases, it happens only occasionally and is barely noticeable, but if untreated, it can result in more frequent occurrences, reduced range of motion in the joint, and arthritic changes. The additional stresses placed on the knee often results in either a single or bilateral ligament rupture, as well. However, it has been proven that the end result can be drastically improved with the use of one of two surgical interventions. The two most commonly used procedures are the trochlear wedge recession and the trochlear block recession.

This photo shows the subchondral bone (with cartilage still attached on top) being lifted free of the joint in a trochlear block recession. (Photo credit: Brian S. Beale)

This article was taken from a study comparing the two procedures in an attempt to determine if the more complex of the two, the trochlear block recession, yielded better outcomes. The older method, the trochlear wedge recession, involved using either a bone saw or an osteotome to deepen the "v" that runs down the middle of the joint surface, the trochlear groove. In this procedure, the cartilage covering the joint surface is lost when the underlying subchondral bone is removed. In the block procedure, though, a rectangular section of the subchondral bone is resected in this region, and then the top layer of cartilage is salvaged and replaced in the joint, pinning the sides to hold it in place if necessary. The study found this newer process to be much more effective in terms of measurable mechanical outcomes.

However, because of the additional investment of time and the higher level of surgical expertise required for this procedure, it is probably not a very feasible or cost-effective option for most general practitioners. Because of this, I was wondering if perhaps a combination of the older approach, the trochlear wedge recession, and the bone scaffold covered in our first SNBAL assignment would be a viable option.

Comparison of trochlear block recession and trochlear wedge recession for canine patellar luxation using a cadaver model.