GEOFFREY HUTCHINSON, DVM, MS, DACVS
WHAT IS A CRANIAL CRUCIATE LIGAMENT RUPTURE
Cranial Cruciate Ligament Rupture (CCL) is a very common problem in canine patients. The cranial cruciate ligament of the stifle (knee) joint normally serves to connect the femur (thigh bone) to the tibia (shin bone) in a way that prevents the tibia from shifting forward during weight bearing. The cranial cruciate ligament also provides rotational stability to the knee.
Rupture of the cranial cruciate ligament may occur from a sudden traumatic
event such as stepping in a hole while running but usually results from gradual, progressive tearing of the thousands of individual fibers. Dogs who suffer from the gradual failure of the CCL are at a 50% risk of eventual failure of the CCL of the opposite knee.
Even if there is not a complete rupture of the ligament, chronic partial CCL tears usually result in moderate persistent lameness, progression of osteoarthritis and muscle atrophy, and will often lead to a full rupture if not treated.
All dogs that rupture their CCL will develop some degree of osteoarthritis. However, with appropriate and timely treatment most dogs will recover very good comfort and use of the limb.
DIAGNOSIS: (Meet your surgeon, confirm the plan)
Diagnosis of CCL rupture varies from one dog to the next and may
occur at the same time as other problems and sources of lameness. It is important that the surgeon evaluate each patient directly with the client present to confirm the diagnosis and determine the appropriate treatment plan. At BBVSH, the surgeon evaluates the patient and discusses the symptoms, diagnosis, and treatment options with each client. Radiographs (x-rays) are taken to assist the diagnosis and to measure for implant size.
Medical management of cranial cruciate ligament rupture usually consists of the use of non-steroidal anti-inflammatory (NSAID) medication, disease- modifying agents of osteoarthritis (DMAOA), rest, and occasionally non- surgical physical therapy. Although these methods will usually improve comfort they do not address joint instability or meniscal injuries and are unlikely to prevent eventual worsening of arthritis and lameness.
Surgery is considered the treatment of choice for CCL ruptures in the dog. Although numerous surgeries exist for CCL rupture there are two main types. Conventional surgery involves using heavy suture material to hold the knee from shifting while scar tissue forms. Although considered more effective than medical management, the reliance on suture and scar tissue make this type of surgery prone to failure especially in larger and more active patients. Conventional surgery is not well-suited to treat partial CCL ruptures. Biomechanical CCL surgery involves cutting and moving a part of the tibia to permanently change the shape of the knee joint. The changed shape makes use of other healthy structures to take the load off of the failed (or partially failed) cranial cruciate ligament. The two most prominent biomechanical surgeries are TPLO and TTA procedures. TPLO (Tibial Plateau Leveling Osteotomy), the first biomechanical technique, was developed in the 1980s to improve outcome over conventional CCL surgery in young athletic dogs. Although amplifying the complexity of CCL surgery, TPLO established that by changing knee geometry and by relying on bone healing rather than scar tissue, consistent good outcomes could be expected.
TIBIAL TUBEROSITY ADVANCEMENT (TTA)
Tibial tuberosity advancement (TTA) is a biomechanical method to treat canine cranial cruciate ligament instability that was originally developed by Kyon in 2001. TTA procedure cuts the forward region (tuberosity) of the tibia and uses implants to secure it in a more forward (advanced) position. This results in the use of the patella (kneecap) tendon to carry the load of the failed CCL. Bone graft is placed into the gap in the tibia and bone heals across the gap over 6 to 8 weeks. Similarly to TPLO, the technique alters the stifle joint geometry to compensate for failure of the cranial cruciate ligament. Unlike TPLO, TTA does not cut across the weight-bearing region of the tibia and does not require elevating muscle from the gastroc (calf muscle) region. Hence, TTA is considered to be less invasive than TPLO. TTA also benefits from the use of titanium implants, which have a lower infection rate than stainless steel implants such as those used in TPLO.
MEDIAL MENISCUS INJURY WITH CANINE CRANIAL CRUCIATE LIGAMENT DISEASE
The meniscus is a disk of firm tissue that acts as a cushion between weight-bearing regions of the femur and tibia. The meniscus becomes torn in at least 50% of knees with a CCL rupture. Finding a torn meniscus is very challenging but if not found and treated there will be marked persistent pain.
Although the meniscus can be approached and evaluated by an open (arthrotomy) procedure, this involves significant cutting of the sensitive joint capsule and the visibility of the meniscus is limited by its position in the back of the joint. Evaluation and treatment of meniscal tears is best done through arthroscopy (use of an illuminated miniaturized camera). Arthroscopy is performed through small point incisions, much reducing invasiveness compared to open joint exploration (arthrotomy). The main advantage of arthroscopy is the much-improved ability to visualize joint structures including meniscal tears. Studies show that arthroscopy is twice as sensitive as open arthrotomy for finding meniscus tears.
ARTHROSCOPY WITH CANINE CRANIAL CRUCIATE LIGAMENT DISEASE
Arthroscopy is a relatively recent introduction to canine orthopedics and due to the equipment and required expertise is usually limited to a specialty hospital setting. In the stifle joint, arthroscopy is used to confirm cranial cruciate ligament partial or complete tears, and to evaluate and treat meniscal injuries. Arthroscopic stifle joint treatment can be combined with most primary cruciate ligament stabilization techniques.
TTA AT BOUNDARY BAY VETERINARY SPECIALTY HOSPITAL
Dr. Hutchinson, an ACVS board-certified veterinary surgeon, has performed conventional and TPLO procedures since 2002. He trained to perform TTA as a less-invasive alternative to TPLO in 2005. As of 2014 he has performed over 800 TTA procedures and performs over 150 TTA procedures annually at BBVSH. Dr. Hutchinson has been invited as a course instructor and to present his clinical experience with TTA at official Kyon TTA courses in New Jersey, Las Vegas, and at the University of Wisconsin.
Dr. Hutchinson has performed stifle arthroscopy since 2002 and has routinely performed stifle joint arthroscopy concurrently with TTA since 2007. Dr. Hutchinson performs stifle joint arthroscopy for cranial cruciate ligament evaluation and meniscus evaluation and treatment under the same anesthesia as the TTA procedure itself. An epidural anesthetic is administered in addition to a general anesthetic. The epidural reduces the required depth of general anesthetic (improving safety) and provides additional pain control for up to 24 hours.
The surgery requires that your pet stay in the hospital overnight before going home. This is important so that he may have a safe recovery
from anesthesia, be given injectable narcotics for appropriate pain control, and so that he may have his dressing changed and incision evaluated for the first 24 hours. Your pet is always under the supervision of a veterinarian and will receive 24-hour care while hospitalized to ensure that he has the best safety and comfort during his post-operative recovery.
During the initial recovery period, your dog will have an incision with staples. It is extremely important to prevent your dog from licking the incision as this may cause an infection. For 10-14 days after surgery you will need to keep the incision clean and dry. For 6 weeks after surgery, exercise restriction is mandatory; this means no running, no jumping, no climbing stairs (off-leash), and leash walks only outside to go to the bathroom. In the house, your dog will need to be restricted to a small confined area with secure footing.
FOLLOW UP CARE
Follow-up visits are scheduled with the surgeon for 2 weeks and 6 weeks after surgery to assess function and monitor healing. Generally your dog will start wanting to walk a few days after surgery. Postoperative pain medications are dispensed and very good return of comfort is expected within 1 to 2 weeks. The surgeon does a recheck evaluation at the time of suture removal (2 weeks) and leash walks of gradually increasing duration are usually recommended (up to 2 hours of leash walking daily may be permitted by the time x-rays are taken at 6 weeks). After the recheck at 6 weeks a gradual return to normal activity is allowed over another 4 to 6 weeks. Clients are encouraged to call or recheck at any time if there is a concern. All routine follow-up visits and x-ray evaluations are included in the cost of the surgery.
As it is with people, dogs gain great benefit from post-surgical physical therapy treatment. BBVSH has an on-site physical therapist who provides treatments to reduce post-surgical pain and inflammation and to improve the return of mobility, strength, comfort, and function following surgery.
All dogs who have CCL rupture will develop some degree of osteoarthritis (OA) within the affected joint. Although this OA prevents complete return to normal, most dogs with will recover the ability to return to comfortable high athletic function within 3 to 6 months
of surgery. Depending on the duration and extent of injury before surgery, most dogs are able to discontinue pain medication following recovery. Any client who does not find their pet recovering this level of function is asked to recheck for a complimentary evaluation.
As with any surgery, complications can occur with a TTA procedure. Complications that are known to occur with this surgery include infection and fracture. As technical errors are the most likely cause of significant complications with TTA, this procedure should only be performed by surgeons who have appropriate experience and who have advanced training in orthopedic surgery. BBVSH uses only Kyon manufactured titanium TTA implants.
LINKS & RESOURCES
DR. GEOFFREY HUTCHINSON
DVM, MS, Diplmate ACVS
A veterinarian who is board-certified as a Diplomate of the ACVS must complete at least one year of internship training and three years of formal residency training under the direct supervision of other ACVS board-certified surgeons. Diplomates must also publish in a peer-reviewed scientific journal and pass a rigourous examination. Dr. Hutchinson completed internships at The Animal Medical Center in NYC in 1998 and at the University of Missouri in 1999. He performed his surgery residency under the direct training of ACVS surgeons at the University of Illinois between 2001 and 2004. Dr. Hutchinson became ACVS board certified in 2006 and has over 10 years of experience in specialty private practice.