What is TPLO Surgery for Dogs?
Tibial plateau leveling osteotomy
(TPLO) is an increasingly popular method for treatment of anterior cruciate ligament injury in dogs. Cranial cruciate ligament (CCL) injuries are complete or partial tears of the ligament or avulsions of the origin or insertion. One sign that is easily apparent besides the dog being lame is that a dog with an injured ACL cannot sit straight. The ACL injuries affect all sizes, shapes, breeds, and ages. ACL Surgery is necessary to correct these injuries. For more information about cranial cruciate rupture (CCL).
Tibial Osteotomy Techniques.
· Tibial osteotomy procedures (TPLO) approach the stifle instability seen with cranial cruciate ligament rupture from a different perspective. Instead of attempting to recreate the damaged or torn cranial cruciate ligament, osteotomy techniques change the geometry of the stifle joint in an attempt to eliminate the shear forces (cranial tibial thrust) seen between the femur and tibia during ambulation. It is important to note that these techniques do not eliminate static cranial drawer movement found on recumbent orthopedic examination.
· On immediate postoperative examination cranial drawer movement will still be palpable but cranial tibial thrust should be eliminated on both examination and during ambulation. Over time, the amount of static cranial drawer motion palpable in dogs that have undergone tibial osteotomy techniques decreases, most likely due to capsular fibrosis.
· Cranial drawer
is a term used to describe excessive cranio-caudal movement of the tibia relative to the femur as a result of cruciate ligament injury
The cranial cruciate ligament (CCL
· CCL is one of the main stabilizing structures of the stifle joint (knee joint). The CCL's function in the dog is to prevent the femur bone from sliding backwards down the slope of the top of the tibial bone (Shin bone).
· The Cranial Cruciate Ligament (CCL) functions primarily to limit cranial translation of the tibia relative to the femur.
· The CCL also limits internal rotation of the tibia; as the stifle is flexed, the cranial and caudal cruciate ligaments twist on each other, limiting the degree of internal rotation of the tibia relative to the femur.
· The anatomy of the canine stifle joint is similar in many ways to the human knee joint. But people don't have an anterior tibial thrust. Our tibia has about a 6-degree angle to the "plateau" of the tibia. People need an ACL for all the diverse movements they do in sports. Dogs do not need an ACL if the top of the tibia is at 6 degrees. Dogs do not do the twisting that people do and don't need the stability of the ACL in the same way that people do.
· CCL failure
can result from degenerative and traumatic causes. The categories are interrelated, because ligaments weakened by degeneration are more susceptible to trauma. The high incidence of CCL failure in dogs suggests that there is an underlying cause of premature degeneration of the cruciate ligament in most cases. Degeneration of the ligament is associated with aging (especially in large-breed dogs), conformational abnormalities (straight rear limbs), and immune-mediated arthropathies. Degeneration of the ligament has also been associated with an increased TPA, although not all studies have identified this correlation. An increased TPA has been theorized to place chronic excessive loads on the CCL leading to eventual mechanical failure. In cats, excessive body weight may significantly increase the risk of CCL rupture.
· Either gender and any age or breed of dog may be affected; however, most dogs brought in for treatment of CCL injury are young, active, large-breed dogs. CCL injury is uncommon in cats.
· Acute injury, chronic injury, and partial tears are three clinical presentations associated with CCL injury.
· Patients with acute tears show a sudden onset of non-weight-bearing or partial-weight-bearing lameness.
· Patients with chronic injury have a prolonged weight-bearing lameness.
· Partial CCL tears are difficult to diagnose in the early stages of injury. Initially, affected animals have a mild weight-bearing lameness associated with exercise; the lameness resolves with rest.
· Dogs of any age may have bilateral subacute or chronic bilateral CCL rupture.
Physical Examination Findings:
· Animals with acute complete tears often are apprehensive during examination of the stifle joint. Instability can be difficult to elicit because of the patient’s apprehension and the resulting muscle contraction. Joint effusion may be palpable adjacent to the patellar tendon. A positive tibial compression test may be easier to elicit than a positive drawer test.
· Cranial drawer movement is diagnostic of cruciate ligament injury. The cranial drawer test is performed with the patient in lateral recumbency.
“The examiner must test for signs of instability with the stifle joint in extension, in the normal standing angle, and in 90 degrees of flexion.”
· The Tibial Compression Test is performed with the patient standing or in lateral recumbency. During weight bearing in the normal dog, forces across the knee joint consist of body weight and muscle forces (quadriceps, hamstrings). Cranial tibial thrust is defined as cranial movement of the tibial tuberosity in the cranial cruciate–deficient stifle when the hock is flexed and the gastrocnemius muscle contracts.
· As force is transmitted proximally, the femur and tibia are compressed together, causing a cranial thrust of the proximal tibia resulting from the caudodistal slope of the tibial plateau. This places passive restraints (e.g., cranial cruciate ligament) under great tension.
· If hamstrings are weak or forces too great (leaping, twisting, turning), the degenerate ligament tears, allowing cranial drawer movement and a positive cranial tibial thrust sign (tibial compression test). In theory, if the caudodistal slope of the tibia is reoriented to a more neutral position (research has shown the proper angle to be 6.5 degrees, with a clinical recommendation of 5 degrees), then the cranial tibial thrust is eliminated. However, excessive correction of the slope places the caudal cruciate ligament at risk.
· Animals of all ages often have periarticular fibrosis on the medial surface of the joint between the medial collateral ligament and the proximal tibial (“buttress sign”).
· With acute tears, radiographs are helpful in ruling out other causes of stifle joint lameness. Radiographic findings in patients with chronic ligament tears or partial tears include compression of the fat pad in the cranial aspect of the joint and extension of the caudal joint capsule caused by joint effusion and osteophyte formation along the trochlear ridge, the caudal surface of the tibial plateau, and the distal pole of the patella. Thickening of the medial fibrous joint capsule and subchondral sclerosis are also evident.
· MRI has been used for evaluation of the cruciate ligament in dogs;
· Arthroscopy. A large percentage of the surface of the cruciate ligament can be examined arthroscopically for gross tears, fibrillation, or discoloration associated with cruciate damage. The menisci and cartilage may also be examined.
· Differential diagnoses include mild joint sprains or muscle strains, patellar luxation, caudal cruciate ligament injury, primary meniscal injury, long digital extensor tendon avulsion, primary or secondary arthritis, and immune-mediated arthritis.
Surgical Treatment: Tibial Plateau Leveling Osteotomy (TPLO).
· TPLO surgery was invented by a brilliant veterinarian named Barclay Slocum. Dr. Slocum's genius was in showing that if the top of the tibia is not sloped, the dog does not need an ACL. He was the first to describe the "anterior tibial thrust
" which occurs every time the dog's leg comes down. The tibia attempts to push forward, but is held in place by the normal ACL, just like a wagon is held on a hill by a rope. This instability results in lameness (limping) and osteoarthritis. Rather than reconstructing the ACL, which is ineffective, the goal of TPLO is to eliminate this instability by changing the biomechanics of the stifle joint.
· This technique entails cutting the proximal tibia, rotating the articular surface, and plating the bone to stabilize the osteotomy. The theory is that by reducing the tibial plateau angle, cranial tibial thrust will be counteracted during weight bearing.
· The learning curve is steeper for the TPLO than for other techniques and potential complications are more catastrophic if the technique is not done appropriately.
· As in all technically demanding procedures
, complications decrease with experience, but this procedure is probably best limited to experienced orthopedic surgeons.
With TPLO Technique
· Each patient’s tibial plateau angle (TPA) and the rotation needed to achieve an end point of 5 to 6.5 degrees are calculated using preoperative radiographs. As with all other surgical therapies for cranial cruciate ligament rupture, the stifle joint is explored via either medial arthrotomy or arthroscopy and meniscal injury is treated if present. This is followed by an approach to the proximal tibia through a medial incision.
· Muscle insertions of the proximal medial tibia are lifted off the bone (gracilis, semitendinosus, caudal belly of sartorius), leaving the medial collateral ligament intact.
· A jig is applied to the medial tibia and guides a curved osteotomy, which will allow reorientation of the plateau to the desired angle.
· During this Surgery, the orthopedic surgeon performs a curved osteotomy (cut in the bone) on the tibia with a biradial saw blade, and the proximal tibia fragment closest to the joint with relation to the rest of the tibia is rotated to the proper TPA angle. The distance of this rotation is based on calculations the surgeon performs before the operation. The surgeon compresses the two resulting pieces of the bones and fixes the tibia in its new orientation with a TPLO plate and screws; both are made of surgical grade stainless steel.
· There are different kinds of bone plate and screws are used to repair.
· We use TPLO locking System (Plate and Screws) from DePuy-Synthes Vet. Please watch The DePuy Synthes Courtesy Video for more information about TPLO procedure and Implants.
· Tibial plateau angle (TPA) is the angle between a line perpendicular to the long axis of the tibia and a line parallel to the tibial plateau
is widely accepted to give the best functional outcome and has enabled working/performance animals to return to high functional standards. There is a trend to a slower progression of arthritis following TPLO surgery, versus dogs that received the MRIT (modified retinacular imbrications technique)
. however, arthritis usually will develop regardless of technique.
associated with this operation and patients’ recovery include: delayed or abnormal healing, breaking and/or loosening of the plate and/or screws, and infection. To minimize the risk of complications while the tibia is healing, we recommend that TPLO patients be kept in a crate (cage) at all times until radiographs (X-ray images) are taken, usually at eight weeks after the operation. Bone healing may take up to 16 weeks in some patients. Rehabilitation exercises are performed at home during this recovery period and may be continued at the Animal Rehabilitation Center. We provide detailed Post-Operative Home Care Instructions
Most animals will be partially weight bearing within 3 to 7 days after surgery and walking comfortably with only a slight limp at 3 to 4 weeks.
General Post-operative Care for Orthopedic Surgery
Choosing a Veterinary Surgeon
TPLO surgery has a very steep learning curve and may be performed by a Slocum TPLO Certified Veterinarian with advanced training for the procedure and experience with successful cases. Dr. Ajaib Dhaliwal has experience of performing advanced orthopedic procedures. When this procedure was developed a few years ago, he recognized it as a superior procedure to the other available options and received his certification for performing the TPLO procedure. He also got more training and experience with Dr. Terri Zachos ( Ex Assistant Prof. MSU) and Claude Gendreau ( Owner of Orthopedics Speciality) Board-Certified Orthopedic Surgeons.
Dr. Dhaliwal is available for TPLO, Free Consultation, Second opinions, or Referrals for the TPLO surgery.
We know you may have a variety of questions about TPLO surgery for your dog. We’ve answered many commonly asked questions here, but you can be certain your dog’s surgeon will answer any of your questions prior to and after surgery.
Q: Does my pet have to spend the night in the hospital?
A: Yes. all dogs undergoing TPLO at Canton Animal Hospital can are discharged next day of surgery.
Q: Will this technique have a negative effect on the opposite leg?
A: No, quite the opposite. The TPLO provides the best possible outcome with no negative affect on the opposite leg.
Q: Will the opposite knee have the same problem?
A: 40% (Forty percent) of all dogs with ACL tears on one side will have the problem on the opposite side. The most effective ways to decrease this percentage are early surgical repair leading to symmetrical weight distribution and weight loss in over-weight dogs.
Q: Is TPLO only for large dogs?
A: No. Many small and toy breed dogs have the greatest degree of tibial plateau slope. Small breed dogs typically have excellent outcomes following TPLO surgery.
Q: What technique would Canton Animal Hospital’ surgeons perform on their own dogs?
A: Unquestionably the TPLO
Q: Is the postoperative period more difficult following TPLO than following older techniques?
A: In our opinion, it is not. In numerous situations, where an older technique had been performed on one side and a TPLO performed on the other side, clients have reported that the TPLO resulted in less discomfort.
Q: Can a TPLO be performed on an animal when an older technique has failed?
A: Yes. In many cases, we have successfully performed TPLOs in patients with failed TTAs, tightrope repairs or Lateral Suture techniques.
Q: Will my dog experience pain in the postoperative period?
A: Minimal. All dogs undergoing TPLO at Canton Animal Hospital receive multi-modal pain management, similar to human orthopedics. Most clients feel their pet’s discomfort level is quite tolerable.
Q: How long does it take for healing?
A: The osteotomy takes 2-3 months to heal. During this time your pet can have a reasonable amount of leash activity.
Q: How many TPLOs have the doctors at Canton Animal Hospital performed?
A: Dr Dhaliwal have performed over 500 TPLOs over the past 12years.
Q: How will I know how to care for my pet after surgery?
A: At Canton Animal Hospital we prepare a detailed set of written discharge instructions for each patient. We carefully review this information with you prior to discharge.
Q: What should I expect when I get home the night of surgery?
A: Your pet will most likely be able to walk (but not well) when you get home. Most patients find their comfort zone once home and sleep the evening and night away. Your pet’s Technician/Surgeon will call the night of patient discharge to check on your pet and answer any questions.
The Ten Most Common TPLO Misconceptions
1. Dogs, like humans, may not require surgery following an ACL tear.
Not true. Unfortunately, the anatomy and biomechanics of the canine stifle (knee) differs from humans. The sloping canine tibial plateau in results in joint sub-luxation (dislocation) during weight bearing. This radiographic animation demonstrates the detrimental instability during weight bearing following a canine ACL tear Because of this, untreated canine ACL tears result in progressive clinical signs, meniscal tearing, severe osteoarthritis (OA) and debilitating lameness.
2.The same surgical techniques used in humans are effective in dogs.
Not true. Replacement techniques using biological grafts are the standard for humans with ACL tears. Similar grafts and techniques have been unsuccessful in dogs due to persistent biomechanical stress. This stress is associated with the sloping tibial plateau present in dogs but not humans.
3. Recovery from a TPLO is more difficult than old style replacement techniques.
Not true. In many instances we have seen dogs with a “fishing line” repair or tight rope have a more prolonged recovery than dogs who have undergone a TPLO.
4. Postoperative pain is greater following TPLO than old style replacement techniques.
Not true. Almost all TPLO patients are very comfortable following surgery. In fact, the surgeons at Canton Animal Hospital find TPLO patients to be more comfortable following surgery than following many other procedures. This comfort is, in large part, due to the stability afforded by today’s bone plate technology. The bone/plate/screw combination provides better stability than any other repair on any other type of tissue. Stability equals comfort.
5. Recovery time is greater following TPLO than “Old Style” repairs.
Partially true. It is true that bone healing takes longer than soft tissues. Old style repairs are as strong as they will ever be as soon as the surgeon ties the knot. However old-style repairs are not as strong as the TPLO at any point after surgery. Bone healing is a double-edged sword; it takes longer to heal but heals stronger than any other connective tissue in the body! Complete bone healing takes about three months but varies from animal to animal and is somewhat dependent on age.
6. Stricter confinement is needed following the TPLO compared to other procedures.
Not true. The TPLO is the strongest ACL technique performed. Following any surgery, dogs require some degree of restriction. TPLO patients should be restricted to the house with leash walks only. Stairs are usually permitted with supervision.
7. TPLO increases the risk of the opposite side tearing.
Not true. In fact, quite the opposite is the case. Because canine ACL tears are caused by biomechanical wear and tear, 40% of animals that tear one side will someday tear the other. The best way to minimize this risk is to equalize weight bearing by performing a TPLO on the affected side. Weight loss is also important in overweight animals. Nearly all dogs left untreated will tear the other side because of shifting weight to the intact side.
8. TPLO is only for show or performance dogs.
Not true. Most surgeons agree the TPLO is the best procedure whether your pet’s an agility star, or lap warmer.
9. TPLO is expensive.
Partially true. Old style repairs can be performed less expensively. The old techniques often involve the use of simple hand instrumentation and a piece of fishing line or suture material. The TPLO involves the use of sophisticated plating equipment, surgical drills and specialized saws. At Canton Animal Hospital we frequently see patients with unsuccessful old-style repairs. It goes without saying these situations result in added expense for the client and additional surgery for the pet.
10. TPLO is only for large breed dogs.
Not true. If fact, small breed dogs often have the steepest tibial plateau slopes and are at high risk for failure following “old style” repairs. It is true that only experienced surgeons should perform small breed TPLO procedures.