Patella Luxation


Figure 1

Patella luxation is displacement of the patella from the trochlear groove or sulcus in the knee. The displacement can occur laterally or medially, although medial displacement is most commonly seen. Patella luxations are usually graded from I to IV based on severity: Grade I luxations can be manually luxated, but rarely luxate spontaneously. Grade II luxations spontaneously luxate when the joint is flexed and remain luxated until relocated by manual pressure or until spontaneous reduction occurs. Grade III luxations are luxated most of the time but can be manually reduced. Grade IV luxations are permanently luxated and cannot be reduced without surgical intervention.


Patella luxation is a common cause of lameness, and most patients with patella luxation also have associated musculoskeletal abnormalities. Patella luxation repair is indicated to restore the knee joint to normal function, and the type of repair will vary depending on each patient’s soft tissue and skeletal abnormalities. Procedures performed to treat patella luxation include trochlear wedge recession or block recession, tibial tuberosity transposition, and joint imbrication. Some severe cases may also need a femoral and/or tibial corrective osteotomy. Surgical treatment of patella luxations is generally indicated on any patient that is showing symptoms (lameness) from the luxation. This includes most grade II, III, and IV luxations.

Postoperative Care

Pain medication is generally only required for the first 10 to 14 days following surgery. Give pain medication only as prescribed and do not give human drugs without first consulting with a veterinarian.

The bandage on your pet’s leg is a soft, padded bandage that controls swelling and provides some support in the early postoperative time. It is not designed to allow running or jumping. The bandage should be checked and/or changed as soon as possible if any of the following are noticed:

  • Swelling of the toes
  • The bandage becomes wet or soiled
  • The bandage has slipped
  • Your pet is chewing at the bandage

If your pet has a tendency to chew, then he/she may need an Elizabethan collar designed to prevent chewing. Bandage removal is usually advised three to five days after surgery, but in some cases it may be left on until the time of suture removal.

Restricted activity is very important for at least 6 weeks following surgery. The surgical procedure involves cutting and repositioning the bones around the knee, so rest is important to allow the bones to heal in their new position. Your pet should be kept in a quiet, confined area (such as a kennel, crate, or small room) when not supervised. Exercise should consist of short walks outdoors only for elimination purposes on a leash. Running, jumping, and playing with other pets should not be allowed.

Please schedule an appointment for suture removal 7 to 10 days after surgery. In addition, please contact us immediately if:

  • Bandage problems are noted
  • Any unusual swelling is noted
  • Discharge of the incision site exists
  • There is any increase in lameness is noted after pet was starting to improve
  • Limping is noticed on any of the other legs


The prognosis for return to normal or near-normal function in the limb is generally good following surgery for most grade II and III patellar luxations. The prognosis is more guarded with grade IV luxations due to irreversible cartilage damage and more severe bone deformities. Concurrent problems in the knee, such as anterior cruciate ligament rupture and arthritis, also negatively affect the prognosis. Potential complications following surgery may include wound and bandage problems, infection, arthritis, and rarely, recurrence of the luxation.

Your pet’s recovery and well-being are our primary concerns, so please do not hesitate to call and speak with a surgical technician or surgeon if there are any questions regarding your pet’s recovery.