What is a cranial cruciate ligament (CCL) rupture?
The cranial cruciate ligament (CCL) is one of several soft tissue structures that stabilizes the knee (stifle) joint in dogs. The CCL is analogous to the anterior cruciate ligament (ACL) in humans. In both dogs and humans, this ligament is one of the most commonly injured ligaments.
What are the treatment options for CCL rupture?
CCL ruptures can be treated surgically or non-surgically. Although there is no convincing evidence showing that surgical treatment is better than non-surgical treatment, surgical treatment is often chosen as a first-line treatment. There are different surgical techniques available, ranging from less invasive surgeries performed by a general veterinarian (such as the lateral suture technique) to more invasive techniques where the bone is cut and fixed to a new position with metal plates (such as TPLO and TTA). The latter two surgeries are performed only by orthopedic surgeons.
CCL ruptures can also be treated non-surgically. Non-surgical treatment has traditionally been regarded as a second-line treatment used mostly for dogs that can’t have surgery due to health or financial reasons. This is a long-held tradition that we are now challenging with the PaladinTM project. In our opinion, non-surgical treatment should be the first-line treatment for most dogs with CCL rupture because of a substantially lower cost and much lesser risk of complications. Non-surgical treatment protocols vary a lot, but often include painkillers, rest, and/or rehabilitation.
What are the risks of CCL surgery?
All surgeries come with a risk of complications. The most common complications of CCL surgery are infection, fractures, additional soft tissue injuries such as meniscal tears, and implant failure. All surgeries require anesthesia or sedation, which also poses a threat especially to older dogs or dogs with major comorbidities. The risk for major complications with CCL surgery is between 20% and 30%, i.e. every fourth or every third dog will get a major complication (1–3).
Why would non-surgical treatment be preferable over surgical treatment?
There are several potential benefits of non-surgical treatment, including:
- Much lower risk of major complications
- Non-invasive treatment
- No need for anesthesia
- Substantially lower cost
- Treatment can start immediately after diagnosis, no need to wait for surgery
- No referral to orthopedic surgeon needed
- Surgery can always be tried later if non-surgical treatment is unsuccessful
About the PaladinTM project
PaladinTM is a recently launched project aiming to evaluate the outcomes of a modern non-surgical treatment protocol for CCL rupture. The treatment protocol consists of an external support device (brace), rehabilitation, and pain medication. Patients are currently being recruited from all over the US.
Fitting and Adjustments
The PaladinTM brace is designed to be customized to each individual patient for the best fit. The neoprene liners (main and front) will need to be trimmed, and heat adjustments for pressure relief, brace height/length customization, etc. may be needed to achieve a comfortable and functional fit.
A heat gun can be used to heat the Woodcast material for adjustment, and cold spray can be used to cool the brace down once the adjustments have been made. A blow dryer and cold water can be used for adjustments as well, it just may take a little longer to heat up and cool down. Please refer to the videos under the Study documents & Instructional videos tab above for more information.
Patients participating in the study may need to wear an e-collar during the treatment when not closely monitored to prevent chewing on the brace.
Tarsal PROM exercises are encouraged during air-breaks from the brace to prevent tightening of the tarsal joint and associated soft tissues.
If necessary, the brace can be removed at night. Please note that the usual treatment time of two months to achieve the desired muscle reprogramming may take longer if a patient is able to bear weight on the affected leg when not wearing the brace.
Why is this study needed?
Although CCL rupture is the most common orthopedic condition in dogs, there is very little research on the treatment of CCL rupture. The research is particularly sparse for the non-surgical treatment options, which has led to the common belief that surgery is the only viable treatment option for CCL rupture. In general, a less invasive treatment (non-surgical treatment) is always preferable to a more invasive treatment (surgery) if the end result is similar. To this date, there are almost no studies investigating the outcomes of modern non-surgical treatment. Hence, it cannot be known which treatment option leads to better outcomes. If non-surgical treatment would prove to yield similar outcomes as surgery, but at a lower cost and lower risk, this would be a major breakthrough for the whole veterinary orthopedics field.
What evidence is there that non-surgical treatment can work?
There is only one randomized controlled trial (high-quality evidence) comparing surgery to non-surgical treatment. This study from 2013 compared non-surgical treatment (painkillers + weight loss + rehabilitation) to the most common surgery for CCL rupture (TPLO). The authors report that there was no significant difference between investigator-assigned lameness and pain scores at any time during the 12-month study (exact numbers not reported) (4). According to an arbitrary definition of “successful outcome”, more than two thirds of the dogs in both groups had a successful outcome at one year (64% vs 75%).
There are also two observational studies (i.e., descriptive case series without comparison group) dating back to the 1970s and 80s that show that even a poor non-surgical treatment protocol consisting mostly of cage rest and painkillers leads to good outcomes in most dogs, especially smaller breed dogs weighing less than 20 kg / 44 pounds.
How would non-surgical treatment heal the ligament?
One of the most common surgical techniques to manage CCL rupture is the extracapsular lateral suture technique, where a fishing line-like suture is placed to stabilize the stifle joint. Contrary to common belief, the lateral suture technique is not designed to be a permanent cure. The suture will loosen or break with time, but as long as it stays in place for 8–12 weeks, the structures surrounding the knee will have time to heal and adopt by developing scar tissue (also called periarticular fibrosis). This scar tissue compensates for the torn cruciate ligament and stabilizes the joint enough to enable normal knee function once the temporary suture loses its function.
The PaladinTM brace works by the exact same principles, by providing temporary support to the knee joint until enough scar tissue has developed to make the knee stable on its own. The major difference is that there is no need for surgery. The brace can be easily applied and removed as necessary. Because the mechanism behind both treatment options is similar, they should lead to similar outcomes. Our mechanical engineers have worked hard to ensure that the PaladinTM device provides adequate support and is safe to use.
What if non-surgical treatment doesn’t work?
The idea of non-surgical treatment for CCL rupture has been borrowed from human medicine, which, for obvious reasons, is usually some decades ahead of veterinary medicine. For humans with cruciate ligament rupture, the recommended treatment for most patients nowadays is to try non-surgical treatment first, and if it does not work, undergo surgery later. By doing this, around two thirds of highly active people can return to sports without having surgery, thereby avoiding risks and costs of ACL surgery (5). We believe that this kind of thinking should be adopted in veterinary medicine as well.
Exactly as in human orthopedics, there is always the option to undergo CCL surgery later on if non-surgical treatment for some reason would not provide satisfactory results for your dog. Evidence from human studies show that delaying the surgery by several months to try non-surgical treatment first does not lead to inferior long-term results even in highly active people.
My dog has been diagnosed with a CCL rupture. How can I join the study?
To see if your pet/patient qualifies for this study, please complete the Enroll Now survey.
Eligibility to participate in the PaladinTM study includes:
- Pet/patient has a cranial cruciate ligament tear diagnosis
- Pet parent has consulted a veterinarian about the possible benefits and risks of participating in this study
- Participants are willing to have their pet/patient progress monitored for 12 months
What does this treatment cost?
The PaladinTM brace is provided at a reduced cost* if you join the study and complete the required follow-up surveys(baseline, two-week, and two-month follow-up). Any other associated costs of treatment (e.g. medication, rehab, fitting and follow-up visits) are not covered**.
**There will be an additional shipping cost of $60 if we are shipping the brace internationally, or $55 if we are shipping to Alaska or Hawaii
If we do not receive responses to any one of these three surveys within 4 months of the ship date, the credit card provided will be billed for the remaining cost of the PaladinTM brace ($300).
Total brace cost during the study: $500
Why should I join the PaladinTM project?
Compared to surgical treatment, which often costs a minimum of between $3,500 and $5,500, you would be up for some substantial cost savings by joining the PaladinTM project. In addition, your dog would avoid the risks associated with surgery, and you and your dog would be contributing to groundbreaking research that will set the stage for providing a better and safer treatment for dogs in the future.
How to get involved
If you’d like to participate in the study or have any questions, please enroll using the form on our homepage or contact the project coordinator: email@example.com
1. Pacchiana P, Morris E, Gillings S, Jenssen C, Lipowitz A. Surgical and postoperative complications associated with tibial plateau leveling osteotomy in dogs with cranial cruciate ligament rupture: 397 cases (1998–2001). JAVMA. 2003;222(2):184–93.
2. Stauffer KD, Abvp D, Tuttle TA, Elkins BAD, Wehrenberg AP, Character BJ. Complications Associated With 696 Tibial Plateau Leveling Osteotomies (2001-2003). Vol. 42, J Am Anim Hosp Assoc. 2006.
3. Stein S, Schmoekel H. Short-term and eight to 12 months results of a tibial tuberosity advancement as treatment of canine cranial cruciate ligament damage. Journal of Small Animal Practice. 2008 Aug;49(8):398–404.
4. Wucherer KL, Conzemius MG, Evans R, Wilke VL. Short-term and long-term outcomes for overweight dogs with cranial cruciate ligament rupture treated surgically or nonsurgically. JAVMA. 2013;242(10):1364–72.
5. Frobell RB, Roos EM, Roos HP, Ranstam J, Lohmander LS. A Randomized Trial of Treatment for Acute Anterior Cruciate Ligament Tears. New England Journal of Medicine. 2010 Jul 22;363(4):331–42.