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Cruciate Ligament Repair

TPLO

TPLO is an advanced orthopedic surgery for treatment of cranial cruciate ligament rupture in the knee joint of dogs. The cranial cruciate ligament is an important structural support in the knee (stifle) joint. Rupture of this ligament is one of the most common causes of rear limb lameness in the dog, causing severe pain and inflammation in the knee joint.

The cruciate ligament normally keeps the femur bone in position on top of the tibia, with the meniscus (a cartilage pad) acting as a cushion between the bones. When the ligament is torn and the dog bears weight on the leg, the femur slides down the tibia and scrapes back and forth, causing damage to the meniscus and other cartilage in the joint. If untreated it may lead to severe chronic degenerative joint disease (arthritis) in the knee.

Causes of cruciate ligament rupture:knee
Rupture of the curciate ligament may be caused in a healthy joint by a traumatic incident, or it may be the result of gradual weakening of the ligament due to predisposing factors such as obesity, age-related ligament degeneration, pre-existing inflammation, and anatomical abnormalities, particularly excessive slope of the top of the tibia bone causing chronic stress to the ligament.

Symptoms:
An acute traumatic tear of the cruciate ligament results in sudden non-weight bearing lameness in the affected leg. If the disease is chronic due to a predisposing factor, the dog may experience milder episodes of lameness prior to complete rupture of the ligament. Once the ligament tears completely, there will usually be a period of non-weight bearing lameness, which may be followed by the dog gradually starting to bear partial weight on the leg again. Some small breeds of dogs may be able to recover normal use of the leg with only mild arthritic changes. But, larger dogs generally require surgical intervention or they will have debilitating long-term arthritis and pain in the joint.

 

Diagnosisxrays normal:
Cranial cruciate ligament ruptures are diagnosed based upon symptoms and palpation of the joint with the dog under sedation. With sedation the muscles relax and the veterinarian can move the tibia back and forth under the femur freely, called a positive drawer motion, which would be impossible if the cruciate ligament were intact.

Following initial diagnosis and as part of the evaluation for TPLO surgery, the knees will be x-rayed. The condition may occur in both legs from 30-50% of the time.

In the x-rays to the right, the upper X-ray shows a normal leg with the femur in proper position on top of the tibia. In the second x-ray, the ligament is torn, and the femur has slid down the slope of the tibia, causing damage to the joint surface as it grinds bone against bone with weight bearing.
xrays abnormal 

On the abnormal x-ray, the doctor has taken some measurements and marked the x-ray in preparation for the TPLO procedure.

 

 

 
     

TPLO is one of the best surgical optionsxrays repaired
There are several options available for dogs who need surgical correction for cranial cruciate rupture. But, over the last few years TPLO has emerged as the surgery with the best results.

Compared to other options, TPLO generally provides:

  • faster recovery
  • more range of motion for the joint
  • a better return to athletic or working activity
  • less long term arthritis and pain

TPLO surgery levels the top of the tibia, creating a stable surface for the femur and eliminating the sliding action which causes damage to the joint. To accomplish leveling of the tibia, the top of the tibia is cut, re-aligned, and a metal plate is placed to hold the top of the bone in position to heal. During the surgery the torn ligament and the meniscus, if damaged, will be trimmed or removed to reduce inflammation.

In the X-rays to the right, the leg from above has been corrected by TPLO, and the femur is now resting securely on top of the tibia, in a similar position to the normal joint.

 

TTA

The most common knee injury in the dog is rupture of the Cranial Cruciate Ligament (CCL), also frequently called the Anterior Cruciate Ligament (ACL).  This injury can occur at any age and in any breed, but most frequently occurs in middle aged, overweight, medium to large breed dogs.  This ligament frequently can suffer a partial tear, leading to slight instability of the knee. If this damage goes untreated, it most commonly leads to complete rupture and possibly damage to the medial meniscus of the knee.  The meniscus acts as a cushion in the knee.  Complete rupture results in front-to-back instability, commonly called Tibial Thrust, and internal rotation of the lower leg, commonly called Pivot Shift. Untreated legs usually become very arthritic and painful from the instability.

An injured Cruciate Ligament can only be corrected by surgery. There are numerous surgical corrections currently being performed. The most common are 1) External Capsular Repair, 2) Tibial Plateau Leveling Operation (TPLO), and 3) Tibial Tuberosity Advancement (TTA).  This article will focus on the TTA, which is the newest procedure, and probably the best repair for most dogs. The forces within the knee are very complicated and change as the knee is rotated through its range of motion. In a normal standing position there is a tendancy for the lower end of the Femur to slide backwards on the tilted Tibial Plateau, this is called Tibial Thrust. This force can be corrected by either cutting the Tibial Plateau and rotating it into a more flat position (TPLO) or by counteracting this force by changing the angle of pull of the very strong Patellar Tendon by advancing the Tibial Tuberosity (TTA). It has been shown that the TPLO procedure can still allow rotational instability (Pivot Shift) and this may lead to the progression of arthritis as the dog ages.  This Pivot Shift does not seem to be a problem with the TTA procedure because it results in more control of rotation by the large quadriceps muscle which pulls on the Patellar Tendon.  The difference in the physics have been worked out quite well by the researchers. Anyone interested in the details can easily find them by doing an internet search on “TTA vs. TPLO”.

TTA 

The most common knee injury in the dog is rupture of the Cranial Cruciate Ligament (CCL), also frequently called the Anterior Cruciate Ligament (ACL).  This injury can occur at any age and in any breed, but most frequently occurs in middle aged, overweight, medium to large breed dogs.  This ligament frequently can suffer a partial tear, leading to slight instability of the knee. If this damage goes untreated, it most commonly leads to complete rupture and possibly damage to the medial meniscus of the knee.  The meniscus acts as a cushion in the knee.  Complete rupture results in front-to-back instability, commonly called Tibial Thrust, and internal rotation of the lower leg, commonly called Pivot Shift. Untreated legs usually become very arthritic and painful from the instability.

An injured Cruciate Ligament can only be corrected by surgery. There are numerous surgical corrections currently being performed. The most common are 1) External Capsular Repair, 2) Tibial Plateau Leveling Operation (TPLO), and 3) Tibial Tuberosity Advancement (TTA).  This article will focus on the TTA, which is the newest procedure, and probably the best repair for most dogs. The forces within the knee are very complicated and change as the knee is rotated through its range of motion. In a normal standing position there is a tendancy for the lower end of the Femur to slide backwards on the tilted Tibial Plateau, this is called Tibial Thrust. This force can be corrected by either cutting the Tibial Plateau and rotating it into a more flat position (TPLO) or by counteracting this force by changing the angle of pull of the very strong Patellar Tendon by advancing the Tibial Tuberosity (TTA). It has been shown that the TPLO procedure can still allow rotational instability (Pivot Shift) and this may lead to the progression of arthritis as the dog ages.  This Pivot Shift does not seem to be a problem with the TTA procedure because it results in more control of rotation by the large quadriceps muscle which pulls on the Patellar Tendon.  The difference in the physics have been worked out quite well by the researchers. Anyone interested in the details can easily find them by doing an internet search on “TTA vs. TPLO”.