Cruciate Ligament Repair Surgery

Cruciate Ligament Rupture

The Cranial Cruciate Ligament sits inside the knee joint and stops the shin bone (Tibia), sliding forward in relation to the thigh bone (femur). When the ligament tears or ruptures, the joint loses stability and results in inflammation, pain and arthritis. Unlike humans where the cruciate normally ruptures from a single traumatic event, dog’s cruciate ligaments get weaker over time. This almost always results in intermittent or consistent periods of lameness, which progressively get worse without surgical stabilization.

Unfortunately, approximately 50% of patients that tear their cruciate ligament, will tear the other ligament (other leg) in the future, and quick return to function is important to reduce excessive strain on the remaining knee and ligament. Large and giant breed dogs are at higher risk than small breeds.

Clinical Signs

  • Sudden onset lameness in one hind limb
  • No or minimal weight bearing in one hind limb
  • Intermittent limping which worsens with exercise (partial tear)
  • Swelling of the knee joint
  • Difficulty or stiffness rising or jumping


Cruciate ligament rupture or tear can often be diagnosed from a thorough history and physical examination (testing for cranial tibial thrust or cranial draw). Some more subtle tears may require radiographs or arthroscopic exam of the joint to diagnose.


Medical management involves cage rest and exercise restriction for several (3+) months, and is generally only an option for very small dogs and cats. The joint begins to stabilize with scar tissue over several months and results in significantly increased arthritis (when compared to surgical stabilisation). Function of the leg can be termed satisfactory, and requires ongoing management of osteoarthritis and pain.

Surgical stabilisation of cruciate rupture is recommended for almost all cases, and results are superior in 90% of cases.

There are many surgical techniques used to treat cranial cruciate ligament rupture in dogs. The Tibial Plateau Levelling Osteotomy (TPLO) provides excellent results, regardless of patient size, and is the procedure of choice for the majority of cases.

The TPLO involves making a curved cut in the tibia, just below the knee joint, and rotating the bone to a more biomechanically stable position. The effect of levelling the tibia results in reduced force on the cranial cruciate ligament during normal weight bearing. A bone plate and screws (implants) are applied to stabilise the bone whilst healing occurs.

TPLO procedure


Prognosis for dogs that undergo surgical stabilisation is excellent in 90% of cases. Overweight dogs will benefit greatly from reducing to an appropriate body condition.

The cranial cruciate ligament sits in the knee to help stabilise the main leg bones. It can become damaged and rupture completely or partially, causing inflammation, pain and arthritis. Unlike humans where the cruciate ruptures from one traumatic event, dogs tend to rupture their cruciate ligament following weakening over time.

Clinical signs of a cruciate ligament rupture include lameness with very little weight bearing. An injured dog usually holds the limb up. This type of injury typically requires surgery.

Occasionally, the cartilage within the knee joint called menisci can become damaged. These menisci act as a shock absorber between the leg bones and can cause discomfort when damaged.

Common signs of a cruciate ligament rupture:

  • Sudden, severe limping on one rear leg
  • No or little weight bearing on the leg after an injury
  • Mild or intermittent limping in the case of a partial tear
  • Swelling of the knee may occur
  • Difficulty rising or jumping

Predisposition to cruciate ligament rupture:

  • Large and giant breeds are at a higher risk than small breeds
  • Young, active dogs are at higher risk
  • Overweight dogs suffer higher levels of stress on their joints
  • Dogs that have been hit by cars, attacked by other dogs or suffered other forms of trauma
  • Dogs that have previously injured a cruciate ligament in one knee are at an increased risk of injuring the ligament in the other knee at a later date
  • Dogs with relatively long legs
  • Dogs that are spayed or neutered at a very young age may be at a relatively higher risk

Cranial cruciate ligament rupture can be diagnosed from a thorough history, physical examination, x-rays or an arthrotomy (surgical investigation of the joint). Your veterinarian may perform stifle manipulations such as the drawer or tibial thrust test to determine the degree of joint laxity.

Treatment of a cruciate ligament rupture may consist of:

  • Exercise restriction and cage rest for several weeks (8+ weeks). This may be sufficient in small dogs and cats.
  • Weight loss
  • Surgical stabilisation
  • Medical management of osteoarthritis
  • Surgery

There are a number of surgical techniques used to repair the cruciate ligament and/or menisci. We will determine the appropriate surgical technique based on the size of dog and degree of damage.

After surgery
Your pet will remain in hospital until it is fully recovered from the anaesthetic and when its pain is under control.
Homecare following the procedure is extremely important to achieve the best outcomes. Excessive activity can result in poor healing or complications. It is important to follow the strict confinement regime to avoid surgical complications.


Prognosis for dogs that undergo surgical repair is good with improvement seen in 85-90% of cases. Surgery complications are uncommon but may include meniscal injury, infection, implant failure and soft tissue swelling.
Although surgery can slow the progression of arthritis, it is still common for dogs to develop arthritis later in life.
Studies also show that approximately 50% of dogs will rupture the other cruciate ligament within 2 years of each other.

 Once the ligament is torn or ruptures, the knee becomes unstable and inflamed, leading to pain and osteoarthritis. Surgical stabilization is required in a large proportion of cases to avoid debilitating osteoarthritis and chronic pain.  

 At Highton Veterinary Clinic we do several surgical procedures including the TPLO (Tibial Plateau Leveling Osteotomy), and DeAngelis (Lateral Suture) techniques.


TPLO (Tibial Plateau Leveling Osteotomy)

The TPLO is considered a gold standard technique for cruciate ligament repair. The procedure involves cutting and altering the orientation of the tibia bone, which provides dynamic stability to the knee joint. This is important as a stable knee joint slows the progression of arthritis and is much more comfortable to walk on.

The TPLO provides reliable and consistent outcomes, especially in larger (>15kg) dogs.

DeAngelis (Lateral Suture)

The DeAngelis technique involves placement of a prosthetic suture material, which is aligned to stabilize the joint and function as a replacement cruciate ligament.

The DeAngelis technique also slows the progression of arthritis and provides good results in smaller dogs (<15kg).

If your dog needs cruciate repair surgery, please feel free to discuss the procedures with Dr. Luke Ellis at the clinic. Call Highton Vet Clinic (03) 5243 0077 to make an appointment today.

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