Cruciate ligament injuries in dogs are common, especially as many dog breeds have hereditary knee conformation problems which predispose them to ACL tears. As long-term wear and tear causes further degeneration, surgery is the preferred treatment for this type of canine injury.
An ACL injury in dogs is treatable, but vets will most likely recommend that dogs undergo surgery for a torn cruciate ligament rather than non-surgical treatments alone. Dog cruciate repair surgery leads to the best long-term outcomes, as long as the right type of surgical technique is used.
The best type of cruciate ligament surgery will depend on the dog’s weight, lifestyle, and breed. Vets typically recommend bone-cutting (osteotomy) techniques, which are usually superior as they address the underlying conformation issues, but suture methods may be effective for smaller dogs and traumatic injuries.
Read on to learn more about ACL surgery for dogs.
What is a Cruciate Ligament Injury in Dogs?
Cruciate ligament injury (ACL, CCL, cranial cruciate ligament injury, or cruciate disease) refers to the rupturing of the ligament that stabilises a dog’s knee joint. Dogs with this orthopaedic knee disorder often show signs of lameness or knee inflammation.
The ligament, found between the dog’s thigh bone (femur) and shin bone (tibia), can either be partially or completely torn due to trauma or degeneration. Traumatic ruptures can occur in active dogs – for instance, through an awkward landing from a jump. However, degeneration is the most common cause, particularly in large dog breeds with underlying knee conformation problems, as their weight puts extra pressure on the knees.
Some dog breeds like Rottweilers are genetically more disposed to cruciate injury. On the other hand, other breeds such as Greyhounds are genetically less predisposed and don’t suffer this type of injury as frequently.
What are the Symptoms of Cruciate Ligament Injury?
The most prominent symptoms of a cruciate ligament injury include:
- Limping or lameness, which can be persistent or on and off
- Swelling in the knees
- Reluctance to walk or lethargy, especially in normally active dogs
- Difficulty bearing weight when walking or standing
- Muscle atrophy around the knees
- Audible clicking in the knees while walking
- A refusal to bend the knee joint
- Odd sitting or sleeping positions, such as one leg sticking out to the side
What Causes Cruciate Ligament Injury?
Cruciate ligament injuries in dogs can result from either trauma or long-term ligament degeneration. While some dogs can develop these injuries over time due to overexertion, some breeds are genetically more susceptible.
Trauma means suddenly twisting, jumping, landing, or an impact, such as in a traffic accident. In humans, this is the most common cause of knee injuries, but the majority of ACL injuries in dogs are based on the knee’s poor conformation and long-term degeneration.
Unlike trauma, degeneration is the result of chronic wear and tear. The degeneration of the ACL in some breeds of dogs predisposed to the condition, like American Staffordshire Terriers, is the most relevant factor in cruciate ligament injuries in dogs. Poor conformation of the hind legs in some dog breeds causes chronic stress to the ACL, which causes it to degenerate and even rupture under normal load.
Degeneration can be worsened by obesity in dogs since their knees need to carry their weight for long periods. Cruciate ligament injury can still occur in dogs that aren’t predisposed to cruciate injuries, like Border Collies, if they are especially active.
Larger and heavier dogs are more prone to ACL tears in general, both via trauma (like catching a frisbee and landing incorrectly), and long-term degeneration (the mass of giant breeds may take a toll on their knee joints over time).
The risk of athletic injury should not discourage you from playing or exercising with your dogs, though. Dogs without a genetic disposition (and at a healthy weight) rarely rupture their ACL from exercise-related trauma. You can also take many preventative measures to keep your dog’s knees in good condition, including regular exercise and a balanced diet.
However, regardless of your dog’s breed, you should understand the symptoms of cruciate ligament injuries. If you see any signs of pain or lameness in your dog, you should always consult your veterinarian for swift diagnosis and treatment.
How is Cruciate Ligament Injury Treated?
Cruciate ligament injuries are almost exclusively treated with surgery. Surgery is able to address any underlying problems causing degeneration, and is recommended for both big and small dog breeds. Non-surgical methods may reduce symptoms but not address the root cause, and are more common for dogs under 5kg.
Non-surgical treatments for ACL include undergoing rehabilitation therapy, wearing custom knee bracing (orthotics), or restricting activities that encourage inflammation. However, these non-surgical treatments are recommended alongside corrective surgery, not in place of them.
Cruciate ligament surgery has a very high success rate, and you’ll typically find your dog’s recovery from ACL surgery is a smooth one with the right care and attention.
What are the Different Types of Cruciate Ligament Surgery?
Veterinary surgeons often recommend osteotomy or bone-cutting techniques, such as Tibial Plateau Levelling Osteotomy (TPLO) and Tibial Tuberosity Advancement (TTA). These methods address the underlying structure of the joint to allow healing and prevent further wear and tear.
There are also suture-based surgical methods (Extra-Capsular Suture Stabilization and Tightrope) that bring back stability to your dog’s gait. They are not as commonly chosen as osteotomy techniques, and are only recommended for the smallest dogs (under 5kg) and traumatic ruptures.
Triple Tibial Osteotomy (TTO) Surgery
TTO involves a bone-cutting process that uses an implant to realign the knee joint where the joint is opened, and a vertical wedge is cut into the tibia. Then, the gap is closed and screwed. An implant is then fitted into a newly created graft. X-rays are taken after to check the position of the bone and the implant.
TTO was first done in Australia and has proven successful in treating ACL injuries. The implant rarely causes a problem in the dog, so it can be left there for the rest of the dog’s life.
Post-operative management and monitoring last 24 to 48 hours, but dogs can usually walk as early as 12 hours, albeit with some lameness. The adhesive dressing is removed in 3 to 5 days, while sutures are taken out after 10 to 14 days.
Complete rest should be strictly implemented for 6 to 8 weeks. It is often recommended that your dog be confined to one area in the home and taken out to the toilet on a leash. At week 6, it is recommended to go for a follow-up X-ray to assess the healing of the tibia.
Some appreciate the fast recovery after TTO surgery, and the likelihood of postoperative complications is the same as other types of tibial osteotomy techniques. Other advantages are that implants are readily available in TTO, and there are fewer radical changes in your dog’s limbs. However, while complications are rare, they can be more severe with TTO surgery.
When is TTO Surgery Used?
TTO surgery can be done to treat partial or complete ACL tears. It is recommended for big or active dogs, but it works for dogs of any size.
TTO is also used to correct concomitant deformities, such as bow legs (genu varum), knock knees (genu valgum), increased tibial plateau slope angle, tibial torsion deformity, and dislocation (patellar luxation). Dogs can potentially live with these deformities without having to undergo any surgery, but if degeneration and pain occurs, this is when they need to be addressed.
What is the Success Rate of TTO Surgery?
The success rate of TTO surgery is 80% to 90%. Post-operative complications are only reported to be less than 23%, including late meniscal injury (3.1%), implant complications (3.1%), and kneecap (patella) fracture (2.1%).
Tibial Tuberosity Advancement (TTA)
TTA, an osteotomy or bone-cutting procedure, permanently alters the knee joint to remain stable even without a ligament. It was developed in the United States. This technique is ideal for all dogs except those under 5kg.
In TTA, a small incision is made in the knee. Then, the front part of the shin bone (tibia) will be cut and separated, and an orthopaedic spacer or cage implant will be used. The spacer will move the front section forwards and upwards, and the kneecap (patella) will be aligned to prevent abnormal sliding. An X-ray will be taken afterwards.
Post-operative care is essential and may require physiotherapy exercises and massages, depending on the vet’s advice. Crate confinement is strictly recommended for 6 weeks, so movements should only be limited to relieving themselves.
X-rays should be taken after 6 to 8 weeks to check for healing. After 6 to 8 weeks, you may also gradually re-introduce exercises. TTA is less invasive than TPLO and heals faster than other surgeries. Increased range of motion in the knees is also reported.
However, some vets don’t offer TTA because of its risks. During surgery, a fracture can develop. Infections and loose implants may also occur. Post-surgery, a meniscal tear may develop in later life.
When is TTA Surgery Used?
TTA is used in treating ACL, but it’s more common in addressing steep tibial plateau. Dogs with meniscal injuries that require a levelling procedure also undergo TTA surgery because it gives the best pain relief. TTA is more often done for dogs over 12 kg although can be done on smaller dogs provided they aren’t too small and weigh over 5kg.
What is the Success Rate of TTA Surgery?
Even though it seems high-risk, TTA surgeries have a 90% success rate. Some studies, however, conclude that TPLO and TR have better long-term outcomes than TTA.
Tibial Plateau Levelling Osteotomy (TPLO)
TPLO is an ACL treatment that’s osteotomy-based and geometry-modifying. Developed in the US, it is considered a gold-standard correction procedure for ACL. TPLO surgery alters the knee joint, so it won’t need the damaged ligament anymore. It also aims to reduce the abnormal sliding of the tibia when a dog strides.
In TPLO, a semi-circular cut is made on top of the shin bone (tibia). The shin bone is then rotated downwards until it is level with the thigh bone (femur). Then, it is secured with a metal plate or bone plate.
Dogs usually start walking (albeit with a bit of a limp) after 24 hours. Full weight bearing on their injured leg may begin in 2 to 10 weeks. Most dogs return to normal after 12 to 16 weeks. Normal physical activity is possible after 6 to 10 months. Follow-up check-ups and x-rays should be done at weeks four and eight.
TPLO replicates the knee joint better than other types of surgery. Complications are few and far between, and infections also occur less than 10% of the time.
Complications range from implant failure, fracture, infection, and bruising, to osteomyelitis (bone inflammation or swelling). However the vast majority of surgeries are completed with no issues. In addition, surgical complications are usually caused by underlying issues with your dog’s health, not necessarily the surgery itself.
When is TPLO Used?
TPLO is commonly done on medium to giant dog dogs (34 kg and above), especially if it’s caused by trauma. TPLO is still available for small dogs but with an arthroscopically assisted mini-arthrotomy. Like TTA, TPLO is also suitable for dogs with steep tibial plateaus.
What is the Success Rate of TPLO Surgery?
TPLO surgeries are very successful, with 90% to 95% success rates. A year after surgery, 93.1% of limb function will likely return.
Long-term outcomes look bright, and TPLO is deemed superior to TTA surgery. Bearing weight is also faster in TPLO than in ECR. However, TPLO has a higher rate of major complications and meniscal tears than TR surgery.
Extra Capsular Repair (ECR)
ECR (Lateral Fabello-Tibial Suture, extracapsular lateral suture, or ECLS) is a suture-based tightening procedure in which a synthetic substitute for the ruptured ligament is installed against the lateral surface to treat ACL. The implant prevents abnormal sliding and aligns the shin bone to stabilise the knee.
In ECR, the vet creates an incision to access and remove the ruptured ligament and meniscus. The joint is then closed with a suture (usually composed of nylon), with the tension adjusted appropriately. The suture assumes the job of the ligament so that the thigh bone (femur) doesn’t backslide to the flat top of the shin bone (tibial plateau).
Unlike in osteotomy-based procedures, the implant in the ECR can loosen and weaken. That said, scar tissue is expected to grow along and around it.
Dogs can go home 24 hours after surgery, and owners are often taught physical rehabilitation and range of motion exercises to do at home. Physical activities are limited until 8 weeks post-op. After 8 weeks, physical activities should be gradually increased; full recovery is expected after 3 to 4 months.
Follow-up check-ups with the vet are recommended in the second, fourth, and eighth weeks to see how the healing is progressing.
ECR is a trusted method to treat lameness in dogs. The only major risk is if the dog engages in highly active movements and exercises. It can break the suture and require a second surgery. Infection is also possible, but vets ensure a sterile environment during ECR surgery.
When is ECR Surgery Used?
ECR has a good success rate for dogs less than 20 kg. Ideally, the dog is around 14 kg and has a relatively active lifestyle.
When done on larger breeds, the suture will likely snap and be broken even before the scar tissues develop. Dogs with abnormally high tibial plateau slope also won’t benefit from ECR surgery.
What is the Success Rate of ECR Surgery?
ECR has at least an 85% success rate, with infection rates ranging from 1% to 4%. Dogs that have undergone this surgery return to 75% to 80% of their normal function. The irregularity usually manifests in symmetric limb loading, such as when walking or trotting.
Tightrope surgery, sometimes CCL Tightrope (or Tightrope CCL) or just TR, is a suture-based procedure to treat ACL. First developed in the US, Tightrope is already used in humans but is relatively new in veterinary medicine. It is quite similar to ECR except for the suture material, which is much stronger in TR.
In Tightrope surgery, tiny holes are drilled in the thigh bone (femur) and shin bone (tibia). Through those holes, a Kevlar-like biomaterial (FiberTape)—often used in human orthopaedic surgeries—is used to replace the ligament.
Post-operation, a soft cast will be maintained for 2 weeks. After that, low-impact physical therapy exercises should be done in the next six weeks. Generally, the dog is considered recovered in the 8th week.
Dog owners like Tightrope surgery because it is minimally invasive and safer than other procedures. No need to worry about the implant migrating over time. It is also easier and faster to perform and recover from. Tightrope is the preferred procedure if your dogs have a lot of internal rotation.
In bad cases, Tightrope patients may experience implant infection. However, the likelihood of infection or failure is low, and should there be any complications, TR is more readily reversible (or another procedure can be performed). Costs are also relatively cheaper, so some opt for TR over TPLO.
When is Tightrope Surgery Used?
It is best to use Tightrope surgery for small to medium dogs. Similar to risks in ECR, Tightrope sutures may be broken, but are less likely to than those used in ECR. In fact, it is not unheard of that medium to large dogs undergo Tightrope surgery.
However, if your dog is over 34 kg, it is best to opt for TPLO if the budget allows it. The bigger the dog, the higher Tightrope’s effectiveness in the long run.
Steep tibial plateau angles (over 30 degrees) in dogs also decrease the success rate of TR. Old (and less active) dogs or arthritic dogs do well with Tightrope surgery.
What is the Success Rate of Tightrope Surgery?
Like ECR, Tightrope surgery has at least an 85% success rate, and infections are at a minimum of 1% to 4%.
Modified Maquet Procedure (MMP)
MMP, sometimes called MMP TTA, is an osteotomy-based ACL surgery to stabilise the knee joint. It was first developed in the UK. It is like TTA, but simpler and more robust. It uses a titanium wedge, which is more porous or permeable than other implants. This means that the bone that will grow around it is more stable.
In MMP, a short incision is made. Then, the angle of the shin bone (tibia) is modified so that it moves forward. A titanium wedge (Orthofoam) is then inserted to stabilise the joint. The material of the implant allows bone integration, so when the bone heals over the implant, it is more organic. No screws are needed in MMP, only a single pin and staple.
After the operation, crate rest is strictly implemented. By the first week, gradually introduce walking exercises (start with 3 to 5 minutes only). This will strengthen the thigh muscles. Expect good recovery by the fourth to sixth week, and complete healing after 3 months.
Unlike other surgeries, the MMP procedure requires only a small incision, little time, and minimal hardware. The recovery is fast, and the results are good. It is often the choice of dog owners who want their dogs to bear weight faster. MMP is often compared to TPLO, but the former is more affordable.
Complications are rare, but when they do occur, they are quite serious. For instance, the shin bone could be fractured afterwards, requiring major surgery.
When is MMP Surgery Used?
MMP can be done on big and small dogs. But, it is only recommended if the dogs have tibial slopes less than 28 degrees.
What is the Success Rate of MMP Surgery?
MMP surgery can successfully bring back 80% to 90% functionality.
What is the Best Type of Cruciate Ligament Surgery?
For most dogs, osteotomy surgeries are the best solution since they resolve the underlying cause of the degeneration. However, soft tissue procedures can be effective for dogs under 5kg and isolated traumatic ruptures.
Except for the smallest of dogs (<5Kg), osteotomy-based techniques (TPLO, TTA) are superior. These techniques are not designed to stabilise the joint but to reconfigure the conformation so that the ligament is effectively redundant.
Soft tissue procedures that aim to stabilise the joint tend not to be particularly successful as the materials used break, stretch, or fail to restore the normal joint dynamics. They are destined to fail due to poor conformation if there is constant pressure on them.
Soft tissue procedures can be excellent in very small dogs as they tend to be less active, and the strain on the implants is much less due to their low weight. If the ACL has ruptured purely due to trauma, it is again a suitable repair as there will not be an undue strain on the repair. An isolated traumatic ACL rupture is rare in dogs, unlike in humans.
How Much Does Cruciate Ligament Surgery Cost in Australia?
The cost of ACL surgery for dogs depends on the type of technique, choice of veterinary surgeon, and any other procedures that need to be performed. Overall, the cost can range from $2,000 to approximately $7,000.
ACL surgery costs vary depending on the procedure type and the dog’s weight. The more complex the procedure (including the materials for the procedure, like the implant or suture), the higher the cost. Surgery on larger breeds will also cost more due to a larger incision or materials required.
Tightrope surgery is the most affordable type of ACL surgery, but with a lower success rate and suitability, it’s not worth choosing a surgical solution based on price alone. This is because a failed surgery would require further intervention at additional cost – so it’s always best to choose the technique which will give your dog the best results.
How to Prepare a Dog for Cruciate Ligament Surgery
If you suspect your dog has a torn ACL, then you should limit their movement to prevent pressure on their other legs. Go to the vet as soon as possible to verify and ask how to prepare your dog for the surgery. Aside from specific pre-op instructions, preparing your home post-surgery is essential.
Create a safe and comfortable environment after the surgery. You’ll likely have to buy a crate (if you don’t have one yet) and a cone. Then, dedicate a space in the house where you’ll place them. A quiet area is ideal so they can sleep and rest; it also has to be away from stairs or platforms. You will need non-slip rugs around the crate to ensure your dog doesn’t slip on tiles or wooden flooring.
Because your dog won’t be able to bathe a few weeks after surgery, you should also wash them before their operation.
How to Care for a Dog After Cruciate Ligament Surgery
After ACL surgery, make sure to keep up with the pain management, feed your dog well, maintain bed rest, restrict and monitor their movement, create a comfortable environment, and watch for signs of complications or infection. Ensure you follow the vet’s advice as closely as you can, and call your vet immediately if you have any concerns.
Do All Dogs Need Cruciate Ligament Surgery?
Yes, if your dog has an ACL injury it’s almost always recommended to have surgery performed. This is because even partial ACL tears are degenerative, and the problem will only get worse without intervention. However, it’s possible that a dog may not be a good candidate for surgery if they are very elderley or unwell.
Does a Partial ACL Tear Need Treatment?
Any tear creates instability, then inflammation and degradation of the joint, leading to degenerative joint disease (DJD), so the earlier it is treated, the better the long-term outcome. Early treatment is always beneficial, even if the tear is partial. Almost all partial tears will progress to complete tears.
What Happens if My Dog’s Cruciate Ligament Injury Isn’t Treated?
ACL injuries will often lead to complications. As well as ongoing pain and discomfort, untreated ACL in dogs will lead to arthritis or a meniscal tear, which also requires surgery. Since this condition is very painful, your dog’s mobility will be permanently limited without treatment.
This article is published in good faith, for general informational and educational purposes only. Paws and More Vet Centre does not make any warranties about the ongoing completeness and reliability of this information. This article should not be used as a substitute for veterinary advice, including for diagnosis or treatment of a pet’s medical condition. Always consult a veterinary professional before making decisions on your pet’s health.