The prognosis for Grade IV patellar luxation is guarded. Most of these animals have moderate to severe bony malformations and significant arthritis. If correction is performed, it is important to initiate early physical therapy to help restore function. The congenital condition is probably genetic in nature, and as such, affected animals should not be bred. Trauma or injury can also cause patella luxation.
Treatment involves replacing the kneecap into the groove, and preventing it from popping in and out.
The following procedures can be used alone or in combination as necessary to maintain the proper function of the knee. Tightening the joint capsule, known as imbrication, is done on the opposite side of the luxation to prevent the kneecap from having enough slack to pop out of the trochlear groove. Thus a medial patellar luxation is treated with a lateral imbrication, and vice-versa. This procedure relieves the tension that the joint capsule is placing on the patella, thus allowing it to ride in the trochlea. In severe cases a synthetic suture is sometimes necessary to keep the kneecap in place.