PREVENTION, PREVENTION, PREVENTATION!!
The two most significant, preventable risk factors for rupturing anterior cruciate ligaments in dogs are desexing and obesity. This means if you want to reduce your dog’s likelihood of rupturing their anterior cruciate ligaments then DO NOT desex your dog and do not overfeed it.
REPAIRS
Cruciate disease – tears, ruptures, degradation – is the most common orthopaedic disease in mature dogs that may require surgical intervention. The cranial cruciate ligament is a large, strong ligament located within the knee joint. It is a single structure composed of bundles of individual fibres tightly bound together to form the ligament. Joint instability occurs as an accumulation of several minor tears of these fibres and ongoing breakdown of the ligament rather then a complete single tear. When a cranial cruciate ligament is torn, it causes sudden pain and often results in your dog holding its leg up. It also causes instability in the knee joint. Your dog may put the leg down and start using it within a day or so but will continue to limp for several weeks. Normally, at the end of several weeks, the initial pain subsides and the pet is willing to use its leg more; however, the joint remains unstable. Every time your pet puts weight on the leg, the tibia (shin bone) slides forward in relationship to the femur (thigh bone). This abnormal motion causes wear and tear on the joint capsule and cartilages causing pain, inflammation and leads to arthritis. This motion can also put excessive stress on the menisci (C shaped pieces of cartilage within the knee joint) causing damage or tearing. There are numerous surgical procedures that may be performed to improve your dog’s function and delay the onset of osteoarthritis. The most common procedures that we offer are listed below.
Tibial Tuberosity Advancement (TTA)
This operation is based on the biomechanical analysis performed by Dr Slobodan Tepic, which revealed that in order to remove the shear strain from the cranial cruciate ligament the tibial plateaux should be perpendicular to the patellar ligament. There are two basic ways to achieve this; i) advance the tibial crest (the basis of the tibial advancement technique (TTA) described by Professor Montavon and ii) alter the alignment of the tibial plateau to the patellar ligament to 90º (a modification of the Slocum technique). The TTA procedure is designed to move the patella ligament so that it is positioned at 90º to the tibial plateau. This is achieved by first performing an osteotomy of the tibial tuberosity and then advancing it with a titanium cage. The correct cage is selected for both thickness and width and is then secured to the tibia with two stainless steel screws. We have found that this procedure works best in small dogs under 10kg, those dogs with very straight hind legs and some breeds such as Chow Chows.
Triple Tibial Osteotomy (TTO)
Dr Warrick Bruce reasoned that rather than doing one technique or the other, there is merit in doing a little of both to achieve the same outcome as the TTA but with less radical angular changes. In the operation of triple tibial osteotomy (TTO) a small closing wedge osteotomy is performed and this simultaneously advances the tibial crest. The cut bone is secured using a T-plate and six stainless steel screws. This has proven to be a very robust method of reconstruction with very good early return to function. TTO Diagram Handout
Extra-capsular or lateral banding
This is a modification of the DeAngelis procedure, which involves placing a very strong, polyester or nylon band from the back of the femur, across the joint to the front of the tibia. This will tighten up the joint and stabilize it. Over time, scar tissue will form around the joint to form a structure that mimics the function of the normal cranial cruciate ligament. The majority of animals will regain near normal use of their leg after the surgery and after a period of rehabilitation. Total rehabilitation time, can be six to 12 months. This procedure may also be done to provide early stability and augmentation of TTO and TPLO repairs. Unfortunately, the procedure has a high long-term complication rate with implant removal being required in up to 75% of cases and has been shown to be an undesirable procedure in certain breeds of dogs such as Staffordshire Bull Terriers and Boxers.
Outcomes and what we have learnt
As of October 2021 we have performed over 1000 TTOs and 400 TTAs. Surgery time for TTOs is between 75 to 120 minutes and TTA is between 25 to 45 minutes. This includes performing the arthrotomy to remove the damaged remnants of the anterior crucial ligament, inspect the joint and meniscal cartilages.
We have had two major complications with TTOs resulting in secondary fractures of the proximal (very top) tibia. One occurred in an elderly dog with weakened bone and the second occurred following a major side-on collision with another heavy dog. The complications from both of these cases occurred within the first three weeks after surgery. Both were treated with the placement of a temporary external fixateur and subsequently healed as expected. Implant removal has been performed in 11 cases due to persistent fluid accumulation. On average, this is has been performed between three and four years after surgery but in two cases, implants were removed after six months. In no cases, did standard bacterial culture tests on the removed implants reveal infection. However, in all but one of these cases, the patients had histories of intermittent skin infections prior to surgery.
We have had two major complications with TTAs resulting in spiral fractures of the midshaft of the tibia. Both occurred within 14 days of the primary surgery, were related to surgeon inexperience with implant placement and both occurred within the first 20 cases that we performed. These cases required plate fixation of the fractures and subsequently healed as expected. After reviewing both of these cases surgical technique was modified and improved.
We do not bandage the surgeries post operatively. We have found that this creates unnecessary intervention, complication and expense. All dogs will have some degree of post-operative swelling that will last between one and three weeks. We never rest or confine dogs. We have observed that these procedures when performed correctly (regardless of the surgeon) are extremely robust and allow dogs to become functional very soon after surgery. Our in-house comparative data shows that this early return to function makes a significant difference in avoiding muscle wasting and improved function and does not contribute to any significant complications. Unlike graft repairs in people with ruptured anterior crucial ligaments, there is no implanted biological structure in dogs. They are essentially recovering from a broken bone and need weight-bearing stress for healing. Please view the video links below.
No interventional surgery prevents the onset or progression of arthritis – the surgeries provide much better function sooner and for longer. Medium to long-term management of arthritis is best achieved in order by;
1 Weight loss/control – This supercedes everything else put together
2 Continuous moderate exercise and physical therapy,
3. Nonsteroidal anti-inflammatory medication,
4. Hormone replacement therapy if appropriate.
Despite the extraordinary plethora of anecdotes and advertising regarding joint supplements there is very little good evidence that they make the differences claimed. There is an obvious reason why they are sold as supplements and not registered as therapeutic substances. This means that you should turn off your social media and your Google ‘researching’ and take your dog for a walk.