Medial Patella Luxation (MPL)


Also called luxating knee cap or dislocated knee cap.  (“Medial” – to the inside; “patella” – knee cap; “luxation” – out of joint)

Identifying Medial Patella Luxation in Dogs

There are many terms used to describe this defect that many pets are born with. It can be cause by trauma, but most often is there all along, not causing a problem until some form of trauma ensues or arthritis sets in. This defect is most common in small breeds of dogs, but rarely will occur in larger dogs.

Diagram of Medial Patella Luxation

Diagram of Medial Patella Luxation

The patella luxates out of the joint for one or more reasons. The groove that the patella rides in is not deep enough, or the joint capsule that surrounds the joint is not tight enough to hold the patella in place, or the medial thigh muscles pull the knee cap medially, and/or the defect in alignment of the bones above and below the patella pull it in the wrong direction. Some dogs have all four of these defects and some have fewer, but the goal is to repair all of the defects that exist in the knee.

Surgery to Repair Medial Patella Luxation

When the patella is luxated out of the joint, it rides against the bone instead of in the joint causing pain and eventual arthritis. Therefore repairing the knee when your pet is young will help prevent future problems.

Most pet’s knees have only the first three defects present and are easily repaired. The most severe cases involve the defect in the alignment of the bones above and below the knee and require bone to be cut, rotated and pinned to straighten the alignment. At Helping Hands, we do not offer pinning of bones, so are unable to help in these extreme cases. Luckily, most cases are not extreme and we are so happy to be able to help.

If you are unsure if your pet’s knee requires bone rotation for alignment (medically called “tibial crest transposition”), you can ask your veterinarian if they can palpate the alignment of the tibial crest or take an x-ray with the knees perfectly straight up and down to see if the bones are aligned. This x- ray can be sent to us for review if your veterinarian is unsure.

Scheduling Medial Patella Luxation at Helping Hands

While bloodwork ($60) is always suggested, as a cost savings, it is only required on dogs over 7 and cats over 9 years of age. If your veterinarian has run bloodwork within 48 hours of your pet’s procedure, please have them fax it to us or bring us a copy to save you this fee. * E Collars ($15) Many animals chew or lick open their incisions after surgery. We STRONGLY recommend that every animal have an e-collar to help prevent this. If your animal opens his or her incision, you will be charged for closing the wound.

We are outpatient facility which means the pets go home the same day and are usually back to their old selves that night or the next day. While rare, if your veterinarian believes your pet needs post op monitoring, you can return to your full service veterinarian or a 24-hour facility for continued care at your expense. We are here to get your pet through the MPL procedure and back into the hands of your full service veterinarian.


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Helping Hands

1605 Rhoadmiller Street
Richmond, VA 23220

PH (804) 355-3500
FX (804) 355-3009