ACL Injuries in Dogs – Everything You Need to Know!
As dog owners, we hate to see our pets in pain. One common injury dogs face is to their anterior cruciate ligament, better known as the ACL. If you've noticed your dog unable to bear weight on a certain leg, or swelling on the inside of the knee, these may be early symptoms of an ACL injury. Below we cover ACL injuries in dogs, the difference between tears and sprains, symptoms to watch for, how they're diagnosed, and home-care options. (We'll use "ACL," though in dogs it's technically the cranial cruciate ligament, or "CCL" — the terms are used interchangeably.)
ACL vs. CCL
Vets often use "ACL" and "CCL" interchangeably so owners can relate to the injury. The anterior cruciate ligament is the tissue that connects the thighbone to the shinbone at the knee in humans; ACL injuries are common in sports, with symptoms of knee swelling, instability, and pain. The CCL is functionally similar but in dogs — it connects the back of the femur to the front of the tibia, keeping the tibia in place and stabilizing the knee. Symptoms of CCL tears and sprains include swelling behind the leg and favoring one side, with difficulty bearing weight on a leg.
Types of ACL Injuries in Dogs
Is your dog favoring one side, limping, showing swelling behind the leg, or less active lately? Any of these may point to an ACL injury. ACL injuries fall into two forms — sprains and tears — but only a professional can diagnose which. They differ in severity and treatment:
- ACL sprains are typically the less severe injury, occurring when a dog stretches too far or too often — often from a slip, fall, or jump during normal play. A sprain can usually be managed with home care and rarely requires surgery.
- ACL tears are more severe, resulting from the cruciate ligament separating from the bone, usually due to hyperextension of the knee joint. Surgery is the only way to truly repair a tear.
How Are Dog ACL Tears Diagnosed?
For the best diagnosis, see a veterinarian familiar with ACL tears. Diagnosis is based on tests such as the cranial drawer test: the vet positions thumb and forefinger of one hand on the femur and the other hand on the tibia, holding the femur in place while shifting the tibia forward and backward. In a normal, stable joint there's little to no motion; if the tibia slides forward, it indicates cruciate ligament damage. Your dog may be given light anesthesia so they're relaxed enough for an accurate test. Another test is the tibial compression test, and radiographs (x-rays) of the knees and hips can also reveal arthritis or fractures contributing to pain.
Factors That Can Contribute to ACL Injuries
- Large breeds — Labrador retrievers, Newfoundlands, German shepherds, Rottweilers, and Golden retrievers are among the most prone.
- "Weekend warrior" dogs — dogs that get little exercise during the week but then do strenuous activity on weekends.
- Older dogs — dogs over age 5 are more prone to injuries.
- Obese dogs — lack of conditioning combined with excess weight is a common factor.
Any dog — big or small, young or old — can get an ACL injury; these are just factors associated with higher frequency.
Surgery for a Torn ACL
One of the most common questions we hear is "do dogs need surgery for a torn ACL?" Unfortunately, the answer is usually yes — a tear doesn't heal on its own, and if your vet diagnoses a torn ACL, surgery is very likely to be recommended. This is why knowing the difference between a torn and a sprained ACL matters.
How much does ACL surgery cost? Cost depends on your veterinarian, your region, and the severity of the injury. On average, a traditional ACL repair can run between $1,000 and $2,000, though pet insurance can change that. For owners for whom surgery is cost-prohibitive, a joint supplement like Flexpet can help support comfort and is used by some as a long-term aid — but a torn ACL will not heal on its own or with a supplement or medication.
In preparing for surgery, some owners use a joint supplement like Flexpet to help support healthy cartilage, joint comfort, and a healthy inflammatory response. Because it's all-natural, it shouldn't interfere with anything else your vet recommends — but always bring the bottle to your vet so they're informed about what your pet is taking.
Home Care for ACL Injuries in Dogs
Tears need surgery, but sprains can often be managed at home. The simplest approach is rest and restricted activity, which works best for small dogs under about 30 pounds. For larger dogs, your vet may recommend an anti-inflammatory medication for six weeks to two months. An ACL brace is another option — ranging from about $10 to $700 for custom versions — offering therapeutic support and stabilization before and after surgery, or when surgery isn't necessary or feasible.
A home regimen for an ACL sprain may also include an all-natural joint supplement. Look for ingredients like cetyl myristoleate (which supports joint comfort), hydrolyzed collagen type II (which helps renew and maintain connective tissue), and glucosamine sulfate (which supports the joint and cartilage). We recommend Flexpet as a comprehensive daily joint supplement; in the case of a sprain that may not require surgery, it can help support comfort as your dog recovers. Flexpet is a supplement, not a medication — it isn't intended to diagnose, treat, cure, or prevent any disease, and it isn't a substitute for veterinary care.
Flexpet can also be used after surgery to help support comfort, a healthy inflammatory response, connective tissue, and the joints during recovery. If you use it post-surgery, watch your dog carefully and limit activity — many dogs start to feel better and over-exert themselves before they've fully healed.
Flexpet comes with a 90-day satisfaction guarantee. If you're not satisfied with the results, simply return your first order (up to three empty pouches/bottles) for a full refund of the purchase price, less shipping and handling. Questions? Call our customer care team M–F, 9am–6pm EST at 1-800-505-0575.