It is one of the commonest questions I am asked: “My dog has a ligament rupture – should we opt for surgery or not?” To which I normally reply: “Does your dog weigh under 15kg, and is it a partial or full rupture? When it comes to ligament ruptures or tears, there are various aspects to consider, and more than one kind of surgery.”

Whatever the treatment, we want what is best for the long-term health of your pet; there are cases where surgery is avoidable and others where not to operate would be detrimental over the long term. Whether and how to operate will depend on your pet’s weight, size, and specific limb conformation. Both conservative, non-surgical approaches and surgery have the same goal; to improve the stability of the knee, by either mimicking the cruciate ligament or by changing the joint angulation.

Cruciate ligament ruptures are one of the most common causes of lameness in dogs. They’re usually seen in large-breed, middle-aged, active dogs but can occur in dogs of any age and size. In some breeds, such as the Newfoundland, they are hereditary.

The knee joint has two cruciate ligaments – the caudal and the cranial. The cranial ligament is the one that ruptures most frequently and is the focus of this article.

The cranial cruciate ligament (CCL) is responsible for preventing the tibia (the bone in the lower limb) from moving forward. Together with the muscles of the hind leg, the CCL also prevents the knee from rotating internally. It can rupture due to wear and tear over a period of time, or as a result of injury – normally when a dog steps into a hole and turns sharply at the same time.

The cruciate ligament is a vital component for the overall stability of the knee joint; without it, the knee is completely unstable. Instability results in cartilage degradation and inflammation, and eventually arthritis.

In the conservative, non-surgical approach, we attempt to build the muscles around the joint.

When functioning well, these muscles offer dynamic support to the stifle. Strengthening them will strengthen the joint until the joint capsule and the tissues around the knee have thickened and fibrosed. The fibrosed tissue and the muscles will take over the function of the cruciate ligament, providing support for the knee – although never to the same extent as the cruciate ligament would.

There are some drawbacks to the conservative approach. It does not provide the same degree of stability as surgery, and for this reason, may lead to arthritis sooner than when surgery is performed. However, even with surgery, your pet’s knee will be more predisposed to arthritis than before the rupture.

I have had success treating cruciate ruptures conservatively, but success depends on whether the tear is full or partial, and if there is a concurrent meniscal tear. The cranial cruciate ligament has two bands. In a partial tear, one of the bands of the ligament ruptures but the other remains intact. There will be some instability of the knee joint in either flexion (bending) or extension (straightening), depending on which band has ruptured. In a full tear, both bands rupture, causing even greater joint instability and pain.

Also forming part of the knee joint are two C-shaped cartilage structures called menisci. These offer support and cushioning for the joint. In a CCL rupture, the menisci may also become torn and injured and may be a continual source of pain to the dog, preventing success in conservative treatments. Meniscal tears can be difficult to diagnose, but one can sometimes feel or hear a click when the dog bends or straightens the joint – a sure indication of menisci damage. Otherwise, the only way to diagnose damage to the menisci is to open up the joint and look, i.e., to perform arthroscopy.

In my clinic I have successfully treated cruciate ruptures conservatively in the following cases:

  • Full ruptures in dogs weighing less than 15 kg (with no meniscal tear)
  • Partial ruptures in dogs of all sizes and weights (with no meniscal tear).

Dogs heavier than 15 kg do not respond as well to the conservative treatment for full ruptures, because the heavier weight puts greater strain on the knee joint. In such cases, surgery is normally recommended.

When we treat pets using the conservative, non-surgical approach, we aim to:

  • Decrease pain.
  • Build the muscles that support the knee and function of the CCL.
  • Improve the weight-bearing capacity of the affected leg.Improve the range of motion, or the ability of the joint to bend and straighten.
  • Maintain the rest of the body, as there will be secondary muscle tension due to compensation, i.e., the dog’s altered way of moving.

Strategies for the conservative treatment of cruciate ruptures:

Our goal in the conservative approach is to build the correct muscles and to relieve pain. Building the correct muscles is crucial, as this is the only way to provide that initial stability for the knee joint. There are a number of therapies and products that will help with muscle development and pain relief.  My conservative, 30-day approach to cruciate ruptures, whether full or partial, may include the following:

  1. Acupuncture, TENS, Laser Therapy, Magnetic Therapy, Massage (to control the pain as naturally as possible).
  2. Traumeel, oral (a natural treatment for musculoskeletal conditions). Dose: <15kg = 1/2 a tablet twice daily; >15kg = 1 tablet twice daily.
  3. Kaprex (a natural, plant-derived supplement to relieve pain and inflammation). Dose: <15 kg = one capsule daily; >15kg = one capsule twice daily. Tip: Don’t break open the capsule and mix it with food – it is terribly bitter! Check out this video of a dog called Bailey who took Kaprex
  4. Pentosan Polysulphate injections weekly. Click here for clinical studies.
  5. Underwater treadmill and therapeutic exercises to strengthen the muscles that help with knee support.
  6. Custom-made knee orthotics (optional)
  7. Prolotherapy: I have not used this technique myself, but a colleague of mine in South Africa, Dr Wimberly, has had great success with it. It is performed by injecting irritant substances around the knee, causing an inflammatory reaction, and resulting in thickening and fibrosis of the tissues around the joint. This thickening offers the knee the stability it requires. Dr. Wimberly is a surgeon and will often do prolotherapy on the contralateral knee after performing cruciate surgery on the opposite knee. Since doing this, he has had only one dog rupture on the contralateral side. This is a huge improvement on the 66% of contralateral ruptures reported in clinical studies.

Before I begin treatment, I take measurements of the thigh circumference and the range of knee joint movement (a goniometric reading), and I do a lameness score. I take all these measurements again 30 days after starting treatment so that I know whether or not I have achieved the goals I set.

I look for the following improvements:

  • Increase in thigh circumference measurements, which will show an increase in muscle mass and strength.
  • Improvements in the range of motion of the knee joint.
  • Improvements in lameness score.

If the dog has achieved all three improvements after 30 days of treatment, I continue the conservative approach. If there is minimal change, I recommend surgery. In these cases there a reason that the conservative approach is not working, e.g. there may be an undiagnosed meniscal tear.

If there is no improvement after the first month, the likelihood of a successful conservative approach is doubtful. If your pet is not putting more weight on the leg, and not moving the joint better, then muscles are not being built and will begin to waste.   If the muscles keep wasting and your pet gets weaker and weaker, you will eventually need to do the surgery. At a later stage, the outcome will be less favourable because your pet will be weaker and the arthritic process may already have started. When the conservative approach is not working, there’s another good reason to opt for surgery soon;  66% of dogs that rupture one cruciate end up rupturing the other cruciate, because of increased strain on the corresponding opposite joint. This is called a contralateral CCL – something we obviously want to avoid.

If you are considering a conservative approach to your pet’s cruciate rupture, find a trained veterinary rehabilitation therapist to assist you. You want to make sure you approach this correctly.

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The Pet Owner Blog by Dr Megan Kelly