Cranial cruciate ligament repair: One size does NOT fit all
Are you tired of having the debate about what method is best for returning stability to a knee joint with a torn cranial cruciate ligament (CCL)? Goodness knows I can get that way, but like so many things in veterinary medicine, there is no one best answer for all our patients.
Our patients are quite a varied lot, so you can’t treat them with a cookie-cutter approach. Plus, surgical techniques keep getting tweaked, and new ones are coming out all the time! But how do you know if the new procedures are really better? Many surgical options and implants are on the market before they have biomechanical or long-term clinical studies performed. The existence of so many variations on how to solve the same surgical problem yet no concrete superior method being established means the debate rages on. And when there are more than a dozen ways to solve one problem, chances are not a single one of them is perfect.
As in other aspects of veterinary medicine, being aware of your available treatment options and the most current data published about them is necessary to make the most educated decisions for your patients. The key is to find the balance of what the surgeon (that’s you!) is comfortable with and what the best option is for that particular patient.
A word about conservative management
Yes, that’s rest, nutraceuticals, nonsteroidal anti-inflammatory agent administration, pain medications and physical rehabilitation. The veterinary literature will tell you that this approach works for animals that weight 15 kg (about 33 pounds) or less, but I recommend an upper weight limit of 15 pounds for attempting this. Also, if the dog has a meniscal tear or a patella luxation, do not waste time trying conservative therapy—surgery is needed. And while conservative management may take three to six months, if you do not see some improvement in the first month, I recommend surgery.
Cutting into the problem
When a pet owner opts for surgical stabilization, you are faced with a plethora of options. Research is ongoing to illustrate the pros and cons of the newer techniques and newer generation implants to determine the best options. Kinematic and objective, controlled, multicenter prospective trials are needed. But individual patient needs and variation in fibrosis, activity level, meniscal damage and arthritis along with owner time and financial constraints will all play into the decision of the “right” treatment modality for that patient.
Long-term outcomes with intracapsular repair are not as good as extracapsular techniques. For this reason, tibial plateau leveling osteotomy (TPLO), lateral suture and extracapsular braided suture techniques are now the mainstays in small animal cruciate disease. A couple studies have found similar results six months postoperatively when comparing the extracapsular lateral suture and the TPLO. However, the dogs that had their CCL repaired with lateral suture technique tended to be lighter and begin physical rehabilitation earlier than the TPLO group. It is possible that larger dogs treated with a lateral fabellar suture technique may have had a worse outcome.1 More recent studies with equally matched cases showed at any time point up to one year, the TPLO patients functionally did significantly better.2
The current extracapsular technique is usually a lateral fabellar suture. Despite positive clinical results, these techniques do not achieve normalization of stifle biomechanics to the cruciate-deficient stifle and may not be the best option, especially in large or overweight dogs. It also appears that the lateral suture technique leads to more rapid progression of stifle arthritis.3,4
Clinically dogs that have had a TPLO surgical repair are thought to bear more weight than dogs that have undergone extracapsular repair, which hold the leg up for one to two weeks. However, the TPLO surgery involves specialized equipment and is described as having a steep learning curve.
Some finer points of surgery
- Absolutely do not perform two TPLO surgeries on both knees of the same patient during the same surgical visit. Do one knee and then do the other. The complication rate will be much lower—dogs are up and walking and on the new knee and ready for the second surgery in about four weeks.
- I make a small incision (from the femur to tibia, about 1 in long, total) on the medial surface for a “mini-arthrotomy.” Why? Because the medial meniscus is the one that typically tears and you can see it better from there. However, identifying and treating a meniscal tear is one of the hardest parts about cruciate surgery. Do not give up adequate visualization if you are struggling. Hemostasis, tissue handling and exposure are the three vital components to a successful surgery.
- Joint lavage flushes out inflammatory mediators and helps immensely. I always flush with at least 1 L using an isotonic, balanced solution.
- Did you know? Most postsurgical infections are from the patient’s own bacterial flora. Never let any braided suture touch the skin. If I am using braided suture to stabilize the knee, I accomplish everything else before I even take the suture out of its last wrapper.
A few words about the postoperative period
All of the osteotomy techniques require strict confinement while the bone heals. This may be a deciding factor for choosing a repair technique in ill-mannered or outdoor-only dogs. While physical rehabilitation is started early in all dogs, the postoperative exercise restrictions for dogs that have undergone an osteotomy procedure can be weeks to months longer than those that have had a lateral suture technique performed. But early return to function is vital for joint health and to rebuild muscle mass and regain lost bone density.
Keep in mind that when selecting a procedure for an individual patient you need to do what you’re comfortable with. Your experience and preferences matter. Patient attitude and activity matter. And individual patients’ anatomies matter. Yes there has actually been an anatomic mess or two that even I referred to someone else!
1. Au KK, Gordon-Evans WJ, Dunning D, et al. Comparison of short- and long-term function and radiographic osteoarthrosis in dogs after postoperative physical rehabilitation and tibial plateau leveling osteotomy or lateral fabellar suture stabilization. Vet Surg 2010;39(2):173-180.
2. Nelson SA, Krotscheck U, Rawlinson J, et al. Long-term functional outcome of tibial plateau leveling osteotomy versus extracapsular repair in a heterogeneous population of dogs. Vet Surg 2013;42:38-50.
3. Lazar TP, Barry CR, Dehaan JJ, et al. Long-term radiographic comparison of tibial plateau leveling osteotomy versus extracapsular stabilization for cranial cruciate ligament rupture in the dog. Vet Surg 2005; 34:133-141.
4. Gordon-Evans WJ, Griffon DJ, Bubb C, et al. Comparison of lateral fabellar suture and tibial plateau leveling osteotomy techniques for treatment of dogs with cranial cruciate ligament disease. J Am Vet Med Assoc 2013;243:675-680.