Introduction
The anterior cruciate ligament (ACL) is one of the key ligaments in a dog’s knee joint that helps provide stability. ACL injuries in dogs are a common orthopedic problem stemming from sudden trauma or repeated stress to the knee, causing instability or lameness. The injury can progressively worsen over time which usually necessitates surgical repair.
ACL surgery in dogs involves replacing or suturing the torn ligament. While recovery from ACL surgery can take several months, most dogs are able to regain full function in the affected leg with proper rehabilitation and gradual return to activity. Initially after surgery, dogs need to strictly limit exercise to allow the surgical site to heal. As recovery progresses, physical therapy helps rebuild muscle strength and range of motion. With time and therapy, dogs can eventually resume normal levels of activity.
What is the ACL and what is its function?
The anterior cruciate ligament (ACL) is one of the important ligaments that stabilizes the knee joint in dogs. It connects the back of the femur to the front of the tibia, crossing inside the knee joint. Its main function is to prevent excessive forward movement of the tibia in relation to the femur, providing stability especially during activities like running, jumping, or turning.
Without the ACL properly functioning, dogs are at risk of instability of the knee joint which can lead to arthritis over time. A torn or ruptured ACL is a very common injury in dogs that results in acute lameness. Surgery is often needed to stabilize the joint and prevent long-term damage.
Sources:
https://vcahospitals.com/know-your-pet/cruciate-ligament-rupture-in-dogs
How do dogs usually injure their ACL?
ACL tears in dogs most often occur due to sudden twists, jumps, or other forceful movements of the hind legs that cause excessive strain on the ligament. For example, a dog may tear its ACL while running and suddenly changing directions, landing awkwardly after jumping, or slipping on a slick floor. ACL injuries can also result from gradual wear-and-tear over time in some cases.
Some other common causes of ACL tears in dogs include:
- Being overweight – excess body weight puts increased stress on joints and ligaments
- Inadequate exercise – weak thigh muscles can’t properly stabilize the knee joint
- Genetics – some dog breeds may be predisposed to ACL problems
- Conformation – dogs with straight hind legs have higher risk
Proper conditioning and maintaining an ideal body weight can help prevent ACL tears. But due to their active lifestyles, many dogs end up injuring their ACLs at some point. Activities like running, jumping, or playing fetch require rapid starts, stops, and turns that raise ACL injury risk.
Sources:
https://vcahospitals.com/know-your-pet/cruciate-ligament-rupture-in-dogs
What are the symptoms of an ACL injury?
The most common symptoms of an ACL injury in dogs include limping, swelling, pain, and an inability to bear weight on the affected leg (Lagunacanyonvet.com, 2022). Dogs with a partial or complete ACL tear will often suddenly start limping and holding their leg up. There may be swelling around the knee joint. Your dog may vocalize or yelp when you touch their leg, indicating pain. One of the hallmark symptoms is that your dog will be reluctant or unable to bear any weight on the injured leg.
Additional symptoms can include instability in the knee, abnormal sitting, a “bunny hop” way of running while holding the back leg up, and muscle atrophy over time from disuse of the leg (Vetmedbiosci.colostate.edu, n.d.). Your dog may also lick excessively at the knee. These are all signs to watch for that could indicate an ACL injury requiring veterinary attention.
Why is surgery often needed?
Surgery is usually recommended for complete ACL tears in dogs because, unlike in humans, the knee structures of dogs do not heal as well with just rest and immobilization. According to veterinary experts, “dogs with partial tears with surgery because this allows for early return to function and the most rapid return to normal joint mechanics.” (https://vetmedbiosci.colostate.edu/vth/services/orthopedic-medicine/canine-cruciate-ligament-injury/)
The reasons why surgery produces better outcomes than non-surgical options for ACL injuries in dogs include:
- The ACL does not receive a good blood supply, so it typically does not heal on its own.
- Without surgery, arthritis usually develops relatively quickly in the knee joint.
- Resting the knee alone allows for scar tissue, muscle atrophy, and loss of range of motion over time.
- Non-surgical options may temporarily reduce pain but do not stabilize the knee joint long-term.
Therefore, most veterinarians recommend surgery for complete ACL tears in dogs to stabilize the knee and prevent further joint damage.
What does ACL surgery involve?
ACL surgery in dogs involves surgically repairing or replacing the torn ligament in the knee. There are a few different surgical techniques that may be used depending on the specifics of the injury, such as extracapsular suture stabilization, tibial plateau leveling osteotomy (TPLO), and tibial tuberosity advancement (TTA) (Hill’s Pet Nutrition).
Regardless of the exact surgical procedure, the goals are to stabilize the knee joint and promote healing of the damaged ligament. This allows the dog to regain normal function and prevent future injury. Right after surgery, activity is restricted to allow the surgical site to begin healing. As healing progresses over the next 6-8 weeks, exercise is gradually increased through structured rehab activities until the dog can return to normal activity levels (Licks Sleeve).
Some postoperative care may be needed, such as administering medication for pain and inflammation, assisting with physical therapy exercises, and monitoring the incision site. With proper recovery and rehab, most dogs are able to regain excellent function after ACL repair surgery.
Initial Post-Op Exercise Restrictions
In the first 2 weeks after ACL surgery, dogs must adhere to strict crate rest with very limited activity (PetMD). This allows time for initial healing and prevents any reinjury during the fragile initial recovery period. Owners will be instructed to keep their dog crated or in a small pen nearly full-time, only letting them out on-leash for very short bathroom breaks. During this time, dogs should not run, jump, climb, or participate in any exercise beyond slow, controlled leash walks.
One of the main restrictions following ACL surgery is avoiding stairs, with dogs being carried up and down any stairs. This helps prevent putting any sudden strain or torque on the healing knee (Hill’s Pet Nutrition). Early ACL repair relies on precise placement and tensioning of the sutures, thus any wobbling on stairs could damage this repair. Owners must plan for alternate accommodations if their dog would normally climb stairs at home. Limiting activity helps with initial pain management as well.
Gradually increasing activity
After the initial period of restricted activity, dogs can gradually start increasing their activity level. This is typically done slowly over a period of several weeks to months. The goal is to transition to normal activity levels while ensuring the healing knee ligament is not overstressed.
The veterinarian will provide an exercise plan outlining the progression of activity. It often starts with short, leashed walks of just 5-10 minutes, 1-2 times per day. The duration and frequency of these controlled leash walks are increased incrementally each week. For example, walks may be extended by a few minutes every 1-2 weeks. This allows the knee to continue healing while regaining muscle strength and range of motion. Owners must follow the exercise plan closely and not increase activity faster than recommended.
Other low-impact activities like swimming may also be incorporated into the regimen. However, activities like running, jumping, and playing fetch are restricted until the knee is fully healed, usually around 12 weeks after surgery. Throughout the recovery process, dogs should be supervised and prevented from overdoing activity that could re-injure the knee.
It’s important to keep the dog calm in between exercise sessions, allowing plenty of rest. With a gradual return to normal activity over time, the dog can recovery fully while minimizing risk of re-injury (source).
When can stairs be reintroduced?
Most veterinarians recommend waiting 4-6 weeks after ACL surgery before allowing your dog to climb stairs again. This allows time for initial healing and protects the surgical site during the crucial early recovery period. According to PetMD, stairs should be avoided for at least the first month after surgery to reduce strain on the knee joint as it starts to heal[2].
Reed Animal Hospital also notes that stairs should be restricted for 4-6 weeks post-op, as the knee needs time to gain strength and stability[1]. Trying to climb stairs too soon could cause damage, inflammation, and setbacks in the recovery process.
Around 4 weeks, light stair climbing can often be resumed under supervision and with assistance. But it still needs to be approached cautiously and built up gradually. Most vets advise continuing to carry or support dogs up and down stairs until at least 6 weeks after ACL surgery. Some may recommend waiting 8-12 weeks before full free stair access.
Go slowly, limit flights of stairs, and keep sessions brief. Stop if there is limping, pain, or swelling. Onlyincrease stair access as tolerated over time. Patience and conservative, incremental reintroduction of stairs is key. With proper rest and rehab, your dog should regain confident stair climbing ability in the months following surgery.
Long-term recovery outlook
The overall ACL recovery process can take 6-9 months for a dog to fully recover range of motion and muscle strength after surgery. For the first 8 weeks, activity is restricted with gradually increased leash walks and physical therapy exercises. After 8 weeks, the dog can resume short off-leash activity. By 12 weeks, the dog should have good limb use, but activity should still avoid jumping, running and sharp turns. It takes 4-6 months for the ACL graft to be fully incorporated, so impact activity and free running should be avoided during this time. After 6 months, the dog can gradually return to normal activity. The overall prognosis following ACL surgery is good if physical therapy and restricted activity guidelines are followed during the recovery period.
With proper surgical repair, rehabilitation and long-term management, most dogs make a full recovery and can return to an active lifestyle. According to one source, 85-90% of dogs have successful outcomes after ACL surgery if post-op protocols are followed closely. However, even after making a full recovery, the risk of the opposite ACL rupturing in the future is estimated to be 30-40%, so dog owners should be alert for symptoms of ACL injury in the long-term.