CCL Injury or Cranial Cruciate Ligament Injury
+/- Meniscal Tear
The cranial cruciate ligament (CCL) is the primary stabilizer of the knee joint. When the CCL is torn, the bones of the knee move abnormally during activity. This causes pain, inflammation, and abnormal wear in the joint leading to severe arthritis over time.
How is a CCL injury dianosed?
Orthopedic exam - A diagnosis of CCL injury is made on orthopedic examination. Orthopedic examination includes: evaluation of the gait at a different speeds, palpation of the joints and muscles while awake, and palpation of the joints with the pet under sedation.
Knee X-rays - X-rays assist in the diagnosis of CCL injury as well as for surgical planning. X-rays are performed under brief sedation to ensure the x-rays are of diagnostic quality.
Needle Arthroscopy - This procedure involves using a needle-sized camera to enter the joint and evaluate for the presence of a meniscus tear. Brief sedation is required for this procedure.
Blood work - this information helps us to determine the safest approach to anesthesia, pain management, and use of NSAIDs.
How can a CCL injury be treated?
Remember, our ultimate goal is to reduce pain and restore limb function in your pet. To that end, treatment options are aimed at:
Restoring knee joint stability
Removing torn meniscus (if present)
Reducing inflammation and arthritis
Restoring knee joint stability
Restoring stability after loss of the cranial cruciate ligament in dogs is tricky. The ligament cannot be replaced with an artificial or grafted material. Instead, the top of the shin bone (tibia) is altered so that other ligaments and supportive tissues surrounding the knee joint take over the role of the cranial cruciate ligament and restore joint stability. This procedure is called a Tibial Plateau Leveling Osteotomy or TPLO for short. In some smaller patients, a strong synthetic suture can be used as an internal splint while scar tissue stabilizes the knee naturally. This procedure is called a Lateral Fabellotibial Suture, or "lateral suture".
Removing torn meniscus
More times than not, dogs with CCL injury develop meniscal tears due to the abnormal motion in the unstable knee. Typically, dogs will limp on their hindlimb for a days to weeks after the initial CCL rupture that resolves with rest and medical management. Then several weeks to months later they will become profoundly lame on the leg once more after tearing the medial meniscus. Meniscal injury is very painful and many dogs will refuse to bear weight on a leg with a meniscal tear for several days. Once a meniscal tear occurs, dogs are slow to respond to rest and medical management. Removing the torn pieces of meniscus (meniscectomy) from the joint can dramatically improve patient comfort and limb function.
Reducing inflammation and arthritis
All dogs with CCL injury will develop knee arthritis over time. The goal is to slow down the progression of arthritis by reducing inflammation of the joint in every way possible. Restoring knee joint stability with TPLO, and removing the torn pieces of meniscus from the joint go a long way in reducing inflammation and long-term arthritis. Additionally, we can reduce inflammation using medical management such as dog-safe anti-inflammatories, supplements that support joint health, diet modifications, rehabilitation, and complementary therapies such as cold laser and acupuncture.
Dogs will often present to the veterinarian with a sudden limp in the hind leg that may respond to rest and medications initially, but often returns in weeks to months.
Another important structure in the knee joint is called the meniscus, a cartilage cushion located between the bones of the knee. Because of the abnormal motion in the knee joint caused by the loss of the CCL, the medial meniscus gets caught in an unnatural location between the bones of the knee joint during activity. Over time, the medial meniscus becomes injured and tears which causes more pain and inflammation. This commonly occurs 3-6 months after the initial cranial cruciate ligament injury, and is a common cause for lameness to return weeks to months after the initial cranial cruciate ligament injury.
The pain and dysfunction caused by cranial cruciate ligament injury is from three main components:
Instability (abnormal motion) at the knee joint
Presence of meniscal tear
Presence of inflammation and arthritis
The most profound cause of pain and lameness in dogs is through the presence of a meniscal tear. It can be likened to having a pebble in your shoe, only the pebble is a piece of firm cartilage in the knee joint that is crushed between the bones when the dog is active. The instability of the knee also contributes to the pain of the condition and leads to worse arthritis over time. Over months to years the body can develop scar tissue which improves the stability of the knee on its own, but by that time the abnormal wear of the unstable joint has caused significant arthritis. Arthritis is inevitable in dogs with cranial cruciate ligament rupture and contributes to pain, as well. The degree of arthritis over time depends on the timing and approach to treatment.
Medical Management of a CCL Injury
The goals of medical management of cranial cruciate ligament injury are to control pain, reduce inflammation, promote knee joint health, and strengthen the muscles surrounding the knee. Pain is the reason that dogs with CCL limp. If your dog is limping it is safe to say they are in pain. Inflammation is a major source for pain in the knee after CCL injury. Inflammation can be addressed with a combination of dog-safe anti-inflammatory medications, joint health supplements, rehabilitation exercises and integrative therapies such as therapeutic laser and acupuncture. We develop a treatment plan for each pet based on their specific needs, lifestyle, and overall health to maximize pain relief safely.
The following are recommendations for medical management in dogs with cranial cruciate ligament injury:
The simplest and most effective medical treatment for dogs with CCL injury is weight management. Weight management alone can be as effective at reducing pain and improving leg function as treatment with medications. While dogs with normal knees may be able to handle a little extra weight on the body, dogs with CCL injury are not able to without pain and dysfunction. Ideally, dogs with CCL injury should be kept at a thin body condition, with the top of the spine and ribs easily felt when petting those areas.Diet modification is the easiest way to reduce weight in your pet. We recommend actively monitoring your pet’s weight and body condition as they mature to prevent excess weight gain. We can help to design a calorie plan to help your pet stay fit and trim.
Rehabilitation and controlled exercise can dramatically improve limb function in dogs with CCL injury. Specific exercises to strengthen the muscles surrounding the knee can help to support the knee after the loss of the CCL. Therapies such as swimming and underwater treadmill can exercise the muscles with less weight on the painful joint. Explosive exercises such as sprinting and playing should be avoided during this time. Passive range of motion exercises and massage can help to prevent the leg from becoming stiff with limited use. Passive range of motion exercises and massage can help to prevent the hindlimbs from becoming stiff with limited use. Rehabilitation therapy can be combined with therapeutic laser, acupuncture, and in some cases joint injections to maximize patient comfort and outcome to medical management. Exercise to maintain muscle mass can be challenging in some dogs with CCL injury because of the discomfort associated with exercise. A veterinary rehabilitation team can be helpful in these cases to provide rehabilitation exercise service and integrative therapies such as cold laser and acupuncture. They can also create an at-home exercise program and teach you how to perform rehabilitation exercises at home.
Joint Supplements (nutraceuticals)
There are many joint supplements available formulated to nourish the joint cartilage, reduce inflammation, and support health. Omega-3 fatty acids, can help decrease inflammation associated with arthritis. Glucosamine and chondroitin help to provide the building blocks for normal cartilage tissues in the joint. Specially formulated veterinary diets such as Purina JM or Hill’s j/d contain appropriate levels of these supplements. These diets can also be very rich in calories, so it is important to feed the recommended amount, and monitor weight carefully over time. Alternatively, individual nutraceutical supplements such as glucosamine, chondroitin and fish oil (omega-3 fatty acids) can be given as supplements to your pet’s regular diet. An injectable joint supplement called Adequan is also an available option to provide the joints with nourishing material to slow the progression of arthritis. This requires weekly injections for 1 month, followed by monthly injections thereafter.
Non-Steroidal Anti-Inflammatory Drugs (NSAIDS)
These medications (eg. Carprofen, Deracoxib, Meloxicam) are effective at decreasing the inflammation and pain associated with CCL injury and arthritis. NSAIDs are safe medications when dosed appropriately and used in healthy animals. These medications should be avoided in dogs with kidney or liver dysfunction, and should never be used in combination with glucocorticoids (eg. prednisone) to avoid potentially fatal gastrointestinal perforation. We recommend the use of NSAIDs on an as-needed basis to be given only as often as necessary. Some dogs require NSAID medication daily to treat their joint pain. We recommend blood work to monitor kidney and liver values every 3-6 months in patients using NSAIDS long-term.
Dogs that fail to improve with medical management should be reconsidered for surgical treatment to stabilize the knee joint and/or remove the pain of a torn meniscus. For additional information about this condition, visit ACVS.org