Cruciate Rupture in Dogs

You know it makes sense ... 'prevention is better than cure'

Hind Leg Lameness in dogs

Read on to learn more about the most common cause of serious hind leg lameness in dogs seen at Folly Gardens Vets.

The cranial cruciate ligament is an essential component of every knee joint. If it gets stretched or torn it causes pain and instability of the knee which manifests as a lame patient coming to see our vets. It can then lead to damage of other important structures within the knee such as the cartilage pads or menisci which are required for “cushioning” of the knee. A torn menisci also leads to ongoing knee pain. Once damaged the menisci don’t tend to heal well and in humans they are often trimmed if we have a “knee op”.

Keep an eye open at playtime

Cranial cruciate ligaments can be injured during all sorts of fun activities which our dogs love. These include twisting, leaping for balls and landing awkwardly or racing around in the woods and putting a paw down a rabbit hole etc. This explains why it is such a common injury for us to treat.

Why is Cruciate Ligament damage a problem?

Following rupture of the cranial cruciate ligament, the knee becomes unstable. When the dog takes weight on the leg this instability allows the shin bone (tibia) to move forward relative to the thigh bone (femur). The knee feels as though it is ‘giving-way’ and this can cause the dog to appear severely lame. 

When the cruciate ligament breaks, the tibia can then to slip forwards relative to the femur, and this movement, which is known as “Cranial Drawer Movement” can be detected by your Veterinary Surgeon, normally in a conscious dog, but more easily under general anaesthetic or deep sedation when the muscles are far more relaxed

How does TPLO surgery work?

The reason the tibia moves forward when the dog stands on it is that the top of the bone (called the tibial plateau) is not perpendicular (90 degrees) to the length (the axis) of the bone. This is different  to people. Our tibial plateau is parallel to the ground when we are standing upright with our legs straight.

TPLO surgery aims to make the tibial plateau perpendicular to the long axis of the bone and, in doing so, to prevent the tibia moving forwards. The stifle thus feels stable for the dog when weight-bearing, despite the fact that the ligament has been ruptured and not directly repaired.

What does TPLO surgery involve?

Dogs need to be carefully evaluated to see if they need TPLO surgery. Following the initial examination, additional palpation under sedation or light anaesthesia may be necessary. This may enable the detection of more subtle instability of the knee as occurs with partial rupture of the cranial cruciate ligament.

Very specific X-rays (radiographs) need to be obtained of the stifle and tibia The presence and severity of osteoarthritis can be assessed and the angle of the the tibial plateau measured. This enables planning prior to surgery. The position of the cut on the bone, the amount the bone that needs to be rotated, and the size of plate necessary to stabilise the bone in its new position can be evaluated. It may be necessary to take a sample of fluid (synovial fluid) from the knee and send it to a laboratory for analysis.

Antibiotics and painkillers are administered at the time of general anaesthetic and the limb is clipped from the level of the hip to the hock (ankle). Prior to performing the TPLO a small incision or cut is made into the knee joint to enable inspection of the structures within it. Many dogs with ruptured cranial cruciate ligaments tear their cartilages (menisci). Damaged portions need to be removed or these too will become hard and bony, and form “pebbles” or joint mice, within the knee joint which will prevent a proper pain-free recovery. At the same time remnants of the ruptured ligament can also be trimmed.

The tibial plateau is levelled by cutting the tibia with a curved saw and rotating the plateau. Some of the screws are “locked” into the plate which makes the repair stronger.

X-rays are obtained at the end of the operation to assess the new angle of the top of the shin bone (the tibial plateau) and check the position of the plate and screws. A light bandage is sometimes applied.

Long term prognosis

 

Generally this should be good, though certain factors do play a role in determining how good the end result will be. If the cruciate has been damaged for some time before operating, more permanent damage could have resulted in the knee, which may not resolve, even with the surgery. Complications including infection, breakage of the plate or loosening of the screws can occur but are rare. A degree of degenerative joint disease or osteoarthrosis, is inevitable with any surgery to a joint, and the more traumatic the surgery, the more likely this is to occur. The aim of TPLO is to improve function for the patient to better than it was before the procedure.

Risks and complications 

TPLO surgery is a major procedure but fortunately complication rates are low. The potential complications include infection, screw loosening and slow healing of the cut bone (osteotomy).

If infection does occur it is treated using antibiotics. In some cases, surgical irrigation is necessary, and in the worst cases where bacteria adhere to the implants, the implants must be removed after the bones have healed. In the vast majority of animals, the implants remain in place for life and cause no problems at all. Mechanical complications usually occur in dogs that exercise too much before the bones have healed (which takes about 6 weeks). Many mechanical complications are managed with rest alone, although some problems require surgical revision. Other rare complications including sprains and strains around the knee joint can generally be managed using physiotherapy alone.

A small percentage of dogs that didn’t have an injured cartilage at the time of TPLO surgery tear it at a later date (this is called a late meniscal tear).  A sudden increase in lameness usually develops and a second operation is necessary to remove the torn piece of cartilage. However, although there is the potential for complications, in the majority of patients selected to undergo TPLO surgery, knee pain is reduced and function of the limb is improved.

If you have any queries or concerns, please do not hesitate to contact us.

info@follygardens.com

knee
Illustration of a knee Joint including the cranial cruciate ligaments

Any Breed can experience this...

The lameness can vary from slightly lame to totally lame depending on how bad the damage is.

This injury is not specific to a particular breed. However, large breeds can be less nimble and exert greater stress forces through their back legs compared with small dogs. Most dogs with this injury require surgery to repair or replace the ligament. We can do corrective surgery on anything from a Yorkshire terrier to a Rottie!

 

What is TPLO surgery?

This is one of the ways we can repair a damaged cruciate ligament.

TPLO is the abbreviation for Tibial Plateau Levelling Osteotomy. This a surgical procedure used to treat cranial cruciate ligament rupture in the knee joints of dogs. It involves changing the angle of the top of the tibia (the tibial plateau) by cutting the bone, rotating it, and fixing it in a new position with a metal plate and screws.

Does my Dog need TPLO?

Tibial plateau levelling osteotomy surgery is a major procedure with possible complications. As a result it is only performed in dogs where the benefits of surgery outweigh the possible risks and where alternative methods of treatment are less successful.

TPLO surgery is primarily performed in medium, large and giant breed dogs. Occasionally small breeds, particularly terriers, need a similar type of operation to correct an actual deformity of the tibia.

Candidates for TPLO surgery are dogs with a ruptured cranial cruciate ligament that have persistent lameness and stifle joint instability.

Surgery After care

Dogs are naturally rather painful after these procedures and we like to use strong painkillers given

through a drip line while they are in hospital. Normally an overnight stay afterwards is a good idea to allow further infusion of pain relief and to monitor the recovery. After the first day, patients can normally be switched on to tablet or oral liquid pain relief, for the next 7-10days. Skin sutures are removed at ten days and we expect the patient to start using the leg by six weeks post-operatively. Sometimes this can be a lot quicker, from as little as two days, and sometimes it can take a while longer.

Aftercare following TPLO surgery is very important, with rehabilitation taking many months. Courses of painkillers and antibiotics are prescribed at discharge. To prevent excessive licking of the wound it may be necessary to use a plastic Elizabethan collar.

Exercise must be very restricted for the first few weeks until the soft tissues and cut bone heal, and at this stage is primarily for toileting purposes. However, the longer a limb is immobilised the greater the chance of stiffening up due to fibrosis (scarring inside the limb) building up. We like to encourage early return to function through sensible and cautious exercise as early as possible after the operation. However dogs must not have the opportunity to chase a cat or squirrel! Walking on a short lead for 5 minutes five or six times daily is important as it encourages the dog to use the leg, more than allowing unrestricted running around. Hydrotherapy and physiotherapy after the TPLO operation are excellent too, and help to restore the natural function and range of movement to the limb.

At other times confinement to a pen or a small room in the house is necessary with avoidance of jumping and climbing.

After a few weeks, exercise may be gradually increased in a controlled manner (still on a lead). Hydrotherapy may be recommended.

A check-up is necessary six to eight weeks after the operation. Limb and stifle function are checked at this time. X-rays are obtained to evaluate healing of the bone cut (osteotomy). Depending on progress advice is given regarding increasing exercise.

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