Here at Maricamp Animal Hospital, we provide exceptional veterinary healthcare whether it be for basic small pet needs or more complex needs like Patella Luxation.
Patella luxation is a complex orthopedic condition found in most small animal breeds. Because are committed to promoting responsible pet ownership and health-related educational opportunities for our clients we have provided some more in-depth information regarding patella luxation.
If you believe your pet is suffering from patella luxation please call us immediately for a consultation at (352) 624-0300 and our friendly receptionist will schedule your appointment.
About Patella Luxation
Patella luxation simply means “kneecap” that moves outside of the proper location. Associated terms include medial patellar luxation, slipped knee cap, MPL, lateral patellar luxation, LPL, dislocating kneecap, kneecap dislocation, luxating patella. The patella is a small bone inside the tendon of the quadriceps muscle of the thigh. The patella normally rides in a groove with the femur (thigh bone) however if it rides outside that groove then it is considered to be “luxated”.
There are multiple methodologies of reasons for this disease process which include trauma, breed predisposition, congenital or developmental misalignment of the entire extensor mechanism. When patella luxation is diagnosed there is usually a complex of skeletal abnormalities that affect the overall alignment of the hindlimb. Such changes can include but are not limited to an abnormal conformation of the hip joint (hip dysplasia) and abnormal angulation and rotation of the femur and/or tibia crest.
Breeds that are predisposed to this condition is primarily small animal breeds including chihuahua, Pomeranian, Boston terrier, Yorkshire terrier, and miniature poodle. Large breeds are rarer but the following breeds have been known to have this orthopedic condition. These breeds include Akita, Chinese Shar-Pei, Flat-Coated Retriever, Great Pyrenees.
A common sign noticed by owners is an occasional yelping and holding a hind leg up for a few steps. Other signs may include shaking, extending the leg prior to fully using it, and reluctant to go up and downstairs. The lameness (disturbance in the gait) may progress as the disease process gets worse and arthritis continue to develop. The luxations are classified by a Grade chart.
Grade 1 – Patella occasionally pops out of its femoral groove and then pops right back in place. Signs range from none to skipping a time or two.
Grade 2 – Patella rides outside the groove more often than it is in the groove. It can be replaced by manual manipulation (by hand) and will stay in this position for awhile. Patients seem to show more persistent skipping, hold a limb up intermittently and have a mild degree of lameness.
Grade 3 – Patella lives outside the groove all the time and can be manipulated into the correct position however it will soon pop back out. The movement of the patella is a constant grinding of the femur bone creating inflammation and results in severe arthritis. Remodeling and rotation of the bone have started to develop.
Grade 4 – Patella lives outside the femoral groove at all times and can not be reduced manually. This is worst case scenario and rotation of the femur and tibial crest has most likely occurred.
Patella luxation surgery is recommended when the disease is severe and/or the patient is painful from this orthopedic condition. If left untreated, the patella will continue to damage the cartilage of the joint leading to the irreversible development of osteoarthritis. Typically a Grade II through IV are surgically corrected. Patella luxation surgery is achieved by one or more of the following procedures:
Deepening of the femoral groove so that the kneecap sits deeper in the groove
Transposing (moving) the tibial crest which helps realign the quadriceps, the patella, and its tendon
Reconstruction of the soft tissues surrounding the kneecap
Correction of abnormally shaped femurs
Recovery from surgery is just as important, if not more than important than the surgery itself. You will receive specific discharge instructions regarding your dog’s postoperative care. There will be at least a 3 month recovery time of restricted activity which includes leash walking only, increasing walk time, and strengthening muscle exercises. Failure to follow the exercise restrictions and post operative discharge instructions will result in severe complications. If restriction after surgery is not possible then surgery should not be performed and other options should be chosen.
Complications with any surgery are always a risk anytime postoperative human) go under anesthesia. We take as many precautions as possible which include pre-surgical blood work, IV catheter with intraoperative fluids, ECG machine, and a technician monitoring anesthesia. Due to the complexity of these conditions, intraoperative or postoperative complications may occur. These complications can include but are not limited to the following: excessive bleeding, skin infection, joint infection, infection of anchor or any foreign material, fracture of the tibial crest or fibula, surgical implant failure (migration or breakage), etc. These complications may require extended hospitalization and/or additional diagnostics, surgery or referral.