Stifle Orthosis
Is a stifle brace (orthosis) the right solution for you and your dog?
Injury to the cranial cruciate ligament (CCL, also called the ACL) is the most common orthopedic injury in the dog. This injury is due to a partial or complete tear of a ligament inside the stifle (knee). The resulting instability allows the tibia ( lower bone) to move forward and rotate inward relative to the femur (upper bone). Cartilage is damaged by abnormal movement and constant inflammation. The result is painful arthritis, muscle atrophy, and often weight gain due to reduced activity.
Stabilization is recommended for best short and long-term function, quality of life, and comfort. Stabilization is traditionally done surgically either with a joint realignment surgery (TPLO or TTA) or with a pseudo-ligament surgically placed outside the joint (tight rope or lateral suture). These procedures are considered the standard of care and best option for most dogs. In the past several years, the use of custom orthosis (brace) has become available as an alternative to surgery when surgery is not an option because of personal preference or medical reasons. These reasons may include other health issues, unacceptable surgical or anesthesia risk, and advanced age. Typically, it is not a good alternative from a financial perspective because it is not less expensive in most cases in the long run.
Because an orthosis is not the correct therapy for all patients, before choosing an orthosis the following points are important to keep in mind:
Custom or off-the-shelf generic device? The purpose of a stifle orthosis for cranial cruciate injury is stabilization of the joint by limiting abnormal movement of the tibia. Keep in mind the amount of movement in these injured stifle joints is a couple of millimeters to perhaps 2 cm. In smaller dogs or those with a partial tear there is less movement compared to larger dogs. A ridge structure is required to stop this movement. Device designs use different methods so stop movement. Most of them do not work. For example: neoprene stretches too much, in fact most fabric stretches too much. Another concern is fit. If the device doesn’t fit snuggly against the leg there is movement of the tibia within the device. This means the design must be precise AND each time it is strapped on it must be strapped properly; too loose and the device is useless. Because of this Dr. Mich has not found any off-the-shelf device that fits well enough to manage instability. Although custom devices are fitted for an individual dog and thus may be a better choice, these devices must be designed properly. Here are the design elements needed:
The upper shell must extend well up into the groin area, but not irritate. If the upper shell is too short there is not enough control of the upper bone (femur). (Blue square in picture below)
The lower shell must extend all the way to the tarsus (hock = ankle). If the lower shell is too short there is not enough control of the lower bone (tibia). (Yellow triangle in picture below)
There must be a hinge that is aligned with the dog’s stifle (knee) joint. (Green X in box)
There must be an adjustable strapping system with upper strap as high as possible in the groin and lower strap just above the tarsus. (Blue arrow and yellow arrow)
There must be a rigid structure (e.g. strap) just below the front of the joint and one just below the back of the joint at the top of the tibia. These are a part of the biomechanical corrective forces along with the upper and lower straps. Without these the tibia is free to move against the femur. (White arrows)
If you are considering a stifle brace for your dog’s cranial cruciate ligament surgery here are important things to know:
1. The device MUST be put on every morning and removed every night. The device is to be used all day every day, but must be removed at night. It is not like a human knee brace, worn only for sport. This is because of the way dogs stand and move compared to humans. Biomechanics differ greatly when using 2 legs vs 4 legs. The orthosis stabilizes the stifle from the outside only when ON, while surgery does so from the inside permanently. Because of this the orthosis must be used whenever your dog will be standing and moving about. The device is not used at night and your dog should not move about at night (jump on or off bed, wander the house, go outside through a dog door, etc.).
2. The ligament will not heal and so use of the device is for life. Many online sites suggest that a stifle device is only needed until the dog “heals” or the stifle “stabilizes” or “scars down.” This is misleading. The canine cruciate ligament is very small. Also, ligaments are notoriously difficult to heal. For these 2 reasons healing does not occur. The untreated stifle can stabilize somewhat over time, but this is due to scar tissue and arthritis. These limit the functional range of motion of the stifle and pain associated with arthritis needs to be medically managed. Lastly, any unstable stifle will develop fibrosis/scarring and so if the goal is scarring down you don’t need an expensive device to help.
2. Adjustments are expected and are a normal part of the custom orthosis process. If you choose an orthosis to manage cranial cruciate injury the best choice is a custom-made device (see part 1 of this blog). This process starts with a custom mold used to create the device and then custom adjustments on fitting day. Importantly, your dog is much more active at home than at the veterinary clinic. Increased activity and activity intensity can expose fit issues requiring further adjustment usually in the first few weeks to months.
3. Follow-up is critical to success. An orthosis is considered a “durable medical device.” This means that proper use is necessary to meet therapeutic goals and to ensure its safe application over the lifetime of your dog. Annual to twice annual appointments are advised depending on age and activity of your dog. At these appointments Dr. Mich will thoroughly assess your dog’s orthopedic condition and evaluate the condition and fit of the device. Recommendations will be made for continued success in the device.
4. Even with an orthosis, surgery may be required. When the cranial cruciate ligament is torn sometimes the meniscus is also torn. The meniscus is a comma shaped cushion on the inside of the stifle. There are 2, one on the inside and one on the outer side of the stifle. The inner or medial meniscus is most commonly injured and this may occur at the time of the initial cranial cruciate injury or any time later due to too much activity on an unstable joint. A torn meniscus is very painful and if not treated it will cause continued lameness despite stabilizing the joint with surgery or an orthosis. Medial meniscus injury is diagnosed either at surgery, by MRI (rarely), ultrasound where available, or based on clinical examination when possible. A surgical procedure called a partial medial menisectomy is required to manage this injury. It can be done by itself or with a surgical stabilization. If your dog has a torn meniscus you may need to reconsider surgical stabilization rather than an orthosis.
5. The Role of Rehabilitation. Whether your dog undergoes surgical or orthosis stabilization for a torn cranial cruciate ligament and whether or not surgery is required for a torn medial meniscus, it will take time to recover comfortable function. If an orthosis is part of therapy most dogs adapt quickly to wearing an orthosis. Behavioral techniques can facilitate this. Also, your dog will need to learn basic skills while wearing the device. These include: transitions (sitting, lying down, and getting up), stairs, getting into vehicles safely, managing on different types of surfaces (ground, carpet, hardwood floor, etc.). Finally, orthopedic injury leads to compensatory abnormal movement and associated muscle strain and weakness. The best way to ensure the highest level of success is to take your dog to physical rehabilitation. Dr. Mich can recommend a certified therapist or go to our recommended professionals page.
6. A proactive approach to arthritis management is the second key to long-term success. Just as rehabilitation is important whether your dog undergoes surgical or orthosis stabilization, arthritis management is key as well. All dogs will develop arthritis after injury to the CCL regardless of the stabilization techniques chosen. The difference is the severity and speed of development of that arthritis. In general, arthritis develops more slowly and is less severe after surgery compared to an orthosis or no treatment at all. Steps taken early on and continued throughout your dog’s lifetime will make a difference in terms of regaining and maintaining comfort and an active lifestyle well into the senior years. An individualized, integrative arthritis management plan for your dog is important. Dr. Mich is a chronic pain specialist and can provide guidance. See the blog posts on osteoarthritis management.
7. Research: Currently there are no published clinical studies supporting the use of a stifle orthosis of any type for cranial cruciate injury. Despite this various products are available through online entities that may or may not help your dog. It’s important to remember that the amount of instability in the injured stifle is small, from a few millimeters to about 2 cm; therefore, proper materials, design and fit are crucial. Selecting an orthosis as treatment for this injury should be made with the guidance of your family DVM and a veterinary orthotics and prosthetics veterinarian like Dr. Mich. As more research comes available we will report it here.
