A Medially Luxating Patella (MLP) is where the patella (knee cap) moves out of its normal position in the stifle (knee) to the inside of the stifle. Initially, mild MLP’s move in and out of their normal position. This movement in and out leads to wearing of the cartilage under the patella and on the medial condyle of the femur, leading to pain and lameness. Over time, most of these luxating patella’s end up permanently out of their normal position.
Boo, 3 year old Chihuahua, before MLP surgery
These are often suspected on history alone. Owners often report that their pets are seen to skip or hop occasionally. They do this as their patella has popped out and they are trying to flick it back into place. The condition is non-painful until there is cartilage loss and bone on bone contact, and then the animal is lame rather than just occasionally hopping. Palpation of the stifle reveals the patella to be either on the inside of the stifle or is easily able to be moved in and out of its normal position. Crepitus (loss of cartilage and bone on bone contact) may also be present.
Boo, 3 year old Chihuahua, during MLP surgery
In mild cases, where the dog hops occasionally but is otherwise never lame, then weight loss, where appropriate, and stopping rotational activities such as fetching, and use of medication such as Zydax or Cartrophen to look after the cartilage, may mean that MLP surgery is never required. In more severe cases where there is pain/lameness secondary to cartilage loss, then surgery is required. This condition is corrected by chiselling off the tibial crest and moving it further laterally and reattaching with a pin. This redirects the patella tendon and keeps the patella correctly located.
We also deepen the groove in the end of the femur, making it harder for the patella to move out of its correct position. We separate the medial adductor muscles from the thigh muscles to stop the medial pull on these thigh muscles (often initiating up in the hip), leading to more normal tracking of the patella in the end of the femur.
Cost of surgery
This MLP surgery in dogs will usually cost anywhere from $2,000 - $4,000, depending on where it is performed. We perform this procedure for $1,000 - $1,300 in the majority of cases. Our hospital model is based on turnover. We are still very profitable due to our high volume. Our pricing makes the procedure more affordable for our clients, and because we perform so many of them, we are also very good at it.
Recovery and aftercare
Short walks several times per day post-surgery are okay, but we otherwise advise rest for the first four weeks to allow the tibial crest to reattach/heal properly. From this point on, walking increases and by six weeks we start off lead activity. Surgery is the physical part whilst Zydax (pentosan polysulphate) is the medical side. This medication stops the inflammation in the bone and leads to recovery of cartilage covering the previously exposed bony surfaces. We advise use of this as a series of four x weekly injections every six months to avoid arthritis issues long term.
Indi, 8 year old Beagle, 4 weeks post MLP surgery
Poppi, 5 year old Shih tzu, 16 weeks post MLP surgery
Meet Dr. Scot Plummer
Dr. Plummer has been passionate about caring for animals since his childhood, and graduated with Honours in a Bachelor of Veterinary Science from the University of Queensland. South Eastern Animal Hospital allows him to provide your pets with the care they deserve - at a price point that is more affordable.