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Cruciate Information

There are 2 cruciate ligaments in each knee joint. These are small cords which join the bones above and below the knee, effectively holding the knee together. The ligaments can be damaged by a twisting injury to the knee. This is most often seen in dogs that jump or turn suddenly while running. Some breeds seem to have weak ligaments and the ligaments in all dogs get weaker with age and can tear more easily. Damage can also occur in overweight dogs due to the excess strain on the joints. Sometimes the ligament will suddenly tear and this is most likely to occur when your dog is running around during exercise – they will pull up, hopping lame on one back leg. Dogs with cruciate ligament tears stand in a very characteristic way with their back toe just touching on the ground but not taking any weight on the affected leg. Often the ligaments tear slightly to start with, and this may make your dog lame on and off for a while.  Diagnosis of a cruciate rupture is done by feeling the knee joint (which will probably be swollen) and pulling on the ligaments to see if they are damaged. Sometimes it will be necessary to give your dog an anaesthetic to examine the knee properly. We may want to take some X-rays of the knee to see if there has been any other damage to the joint or signs of disease in the other knee. Surgery is often required to provide a good recovery and quality of life. There are a couple of surgical options which the vet will discuss with you and decide which is the best option for your pet depending on their lifestyle, breed, and weight.

The most common repair we perform is called a TTA or MMP procedure, and is recommended for all dogs over 10-15kg, especially if leading an active lifestyle. The operation works by redirecting the force generated by the large quadriceps muscles to compensate for the failed cruciate ligament. This is achieved by cutting free, and moving forward, the part of the tibia (the tibial tuberosity) attached to the quadriceps muscle. The bone cut is called an osteotomy and the osteotomy is stabilised using a modern orthopaedic implant material called an Orthofoam wedge. The porous titanium Orthofoam promotes remarkably rapid bone in growth and healing and this is the key to the reduced convalescence and minimal pain seen with MMP surgery.

Successful recovery after knee surgery, no matter which procedure has been used, requires a period of controlled activity. Compared to other procedures, TTA/MMP causes less discomfort and while a comfortable, pain-free patient is obviously a good thing, many dogs are tempted to use the operated leg too much, too soon. No matter how comfortable and confident your pet is feeling in the days after their operation, it is absolutely essential that running, jumping, and general “rough and tumble” with other pets is avoided for the first 6 weeks or so. The bone must be given time to heal adequately and too much strain placed on the osteotomy too early can result in a stress fracture or implant failure and while this is rarely catastrophic, the ensuing complication may be painful and will certainly delay the recovery.

First and second weeks

Your dog will have a short course of antibiotics and a longer course of a non-steroidal anti-inflammatory drug (NSAID). Treatment with NSAIDs will usually continue for at least six weeks while the osteotomy heals.

Bandages are not used following surgery because it is important that your pet is able to flex and extend the operated knee freely from day one. A gauze pad is sutured over the skin incision to protect the wound. The pad can be removed after five days or so and the skin sutures are removed 10 days after surgery.

During the first 14 days, your pet should be encouraged to take frequent short leash walks – 5-10 minutes six or eight times daily is a good starting point. Ideally, your dog should go outside ON A LEAD to toilet during the first two weeks after surgery.

No other exercise is recommended for the first 14 days – it is important to not let your pet loose to run freely in the house, particularly up and down stairs. 

Third and fourth weeks

The amount of activity can now be gradually increased but it is essential that the patient is not allowed off the leash until allowed by the veterinary surgeon.

Lead walks can be longer, but take care to ensure that the patient continues to use the operated limb confidently at every step.

Fifth and sixth weeks

Bear in mind that although bone healing and remodelling will be progressing nicely, full strength will not be established for several more weeks.

At this stage, the patient will be capable of frequent lengthy (30 minutes or more) lead walks and we will soon be introducing some free running activity. The key to success is a programme of gradually increasing activity. At first, the patient can be allowed off the lead towards the end of the last walk of the day . Choose a quiet area with a good surface – a short cut grassy area is ideal , without dogs or other distractions that might encourage your pet to do too much too soon.  Five minutes is enough for the first day off the lead. Subsequently, the amount of free running play and exercise can be increased gradually back towards normal pre-injury levels. Most dogs will be capable of full, unrestricted athletic activity within 12 weeks of their MMP operation. Some residual low grade stiffness and lameness may still be seen at twelve weeks but this will resolve completely over the following month or two as the patient regains full fitness and the osteotomy completes its healing process.