Cranial Cruciate Ligament (CCL)
Rupture of the Cranial Cruciate Ligament (CCL) is the most common orthopaedic injury that occurs in our canine patients every year. This is referred to as the ACL or Anterior Cruciate Ligament in humans and is almost always caused by acute trauma.
In dogs, CCL injury can occur as an acute trauma or more commonly, is the result of a degenerative process that leads to early and progressive arthritis. CCL causes pain and lameness, and increases the risk of injury to other structures of the knee, such as the meniscus. Techniques used to repair this injury in humans do not work well for dogs because of factors such as conformation. In dogs, the CCL cannot be repaired or reattached. Surgical options for dogs with this injury are based on stabilising the joint with nylon (other options), using extracapsular stabilisation or dynamically altering the biomechanics of the joint using the TPLO or TTA.
Arthroscopic surgery is a key investigative tool in orthopaedic surgery due to its minimal disruption of the joint structure and rapid recovery time.
Canine elbow dysplasia is the main cause of canine forelimb lameness. Elbow dysplasia is a set of diseases which include osteochondrosis (OCD), fragmented coronoid process (FCP) and united anconeal process (UAP). These diseases have different patho-physiology but lead to elbow arthrosis.
There are many different genes that contribute to elbow dysplasia with both environmental and hereditary influences. Degenerative joint disease can lead to decreased range of motion in the elbow. In immature large dog breeds, this usually indicates the presence of elbow dysplasia.
Both limbs should be radiographed even if one limb is clinically lame. This is because if an animal is extremely lame on one leg, it is hard to assess lameness in the contralateral limb. Surgical removal of the bone and cartilage pieces via arthroscopy improves limb function.
Blunt trauma of the elbow can cause lateral luxation of the radius and ulna. Surgery of traumatic luxations can involve open reduction of the elbow luxation or elbow arthrodesis.
If either the ulna or the radius does not grow to its expected length due to closure of a growth plate to early, it can lead to deformity. This can be due to either trauma to the immature bone causing the growth plate to close early or it can be in chondrodysplastic breeds due to asynchronous growth causing incongruity. If untreated, the elbow joint would be painful and will lead to degenerative joint disease. Surgery can include ulnar lengthening osteotomy, ulnar shortening osteoectomy or radial lengthening.
Dr William McCartney of NOAH (North Dublin Orthopaedic Animal Hospital) was the first veterinary orthopaedic surgeon to do total elbow replacements, PAUL procedure, sliding humeral osteotomy, arthroscopy and arthroscopic surgery for medial compartment disease.
Many humans will be familiar with hip osteoarthritis due to either development issues or trauma. The hip is a versatile joint that provides much of the power of the hind limb, whilst having the biggest range of motion of any joint in the body. Painful osteoarthritis can be particularly difficult to adjust to. The first route of treatment is pain relieving anti-inflammatories which can be hugely successful in managing the pain. But there are problems with using long term medicine to control pain and gastrointestinal ulceration can occur. As well as that, some dogs simply cannot tolerate the medicine.
In these cases, the dog can have either a triple pelvis osteotomy (if less than 12 months) for hip dysplasia, femoral head and neck excision, or total hip replacement for any size of dog.
Triple pelvic osteotomy is a major operation to rotate the pelvis outward to cover the femoral head better than before by creating a virtually normal joint. It has its limitations in that it must be performed before 12 months for best results. Femoral head and neck excisions may be used in some cases and can provide a pain free scar joint. Although reduced in total range of motion, it can be successful in certain cases.
The knee joint in dogs (known as the stifle) is similar to humans. Because we stand upright, there is minimal stress to the ligaments in our knee. Dogs, however, stand with the ankle elevated and the knee forward. The top of the dog’s tibia (tibial plateau) is sloped and weight bearing creates a force that pushes the femur down the slope of the tibia. This force is called ‘tibial thrust’ and it is the job of the CCL to prevent this motion. Each time the dog bears weight, the CCL is under tension. When the ligament is ruptured, each time the dog bears weight this motion occurs and causes discomfort. When the CCL is ruptured (even partially), there will be inflammation and swelling, referred to as synovitis and effusion. The two menisci are the ‘shock absorbers’ of the knee and are located between the femur and the tibia. When the knee is unstable due to a CCL rupture, either complete or partial, the menisci are at risk for injury.
Two of the most common conditions are cranial cruciate rupture and patellar luxation, which in human terms would be anterior cruciate rupture and slipping kneecap.
Other conditions that require surgery are fractures, dislocations, OCD, LDE avulsion, patella ligament rupture, septic arthritis and miscellaneous conditions. If the problem is not correctable or is beyond salvage, then a total knee replacement or stifle arthrodesis can be done to allow continued function.
Rupture of the Cranial Cruciate Ligament
It is rare for a single incident to cause a sudden complete rupture of the CCL ligament. If this occurs, it is painful and non-weight bearing. A rupture can also occur over incrementally over a long period. Dogs with a high tibial plateau angle (greater slope) have greater stress to the CCL and the ligament can tear partially. Dogs can also partially tear the ligament due to an incident. When a dog has a partial rupture, the dog typically has an intermittent lameness. Partial ruptures can progress to a complete rupture within weeks to months.
Actions that could cause a rupture include:
- Hyper-extension and internal rotation of the knee from sudden turns
- Stepping into a hole
- Repetitive normal activities, and
- Degeneration associated with ageing.
- Obesity is also an increased risk of a rupture as can the ‘weekend warrior’ routine, in which the pet is relatively inactive during the week but very active on weekends.
Dogs that have ruptured the CCL in one knee have a 50% to 70% greater chance of rupturing the CCL in the other knee. Therefore, surgical correction is recommended as soon as possible to decrease the stress placed on the uninjured CCL, thereby decreasing the risk of CCL rupture to that knee.
What are symptoms that my pet has a rupture of the CCL?
Complete rupture results in a non-weight bearing lameness. In the case of a partial rupture, the pet will be weight-bearing lame or have an intermittent lameness. Lameness will often worsen with activity. Stiffness upon rising and/or a stiff gait is another common complaint. You may note that your pet sits with the affected leg out to the side. He or she may have difficulty rising and be less active. Physically, you may note a swelling or thickening of the knee and muscle atrophy (wasting) in the affected limb. Dogs that have ruptured the CCL in both knees do not have lameness in a particular limb since he or she does not have a good limb to stand on.
Extracapsular Stabilization/Lateral Suture Procedure
Extracapsular Stabilization stabilizes the stifle joint with placement of a non-absorbable suture material, typically a mono-filament nylon such as fishing leader line, around the lateral fabella and through a hole in the tibial crest mimicking the pattern of the CCL. Although often referred to as an ‘artificial ligament’, the suture provides only temporary stabilization and will loosen over time. This technique relies on scar tissue to ultimately stabilize the joint. Recovery time following the Extracapsular Stabilization is approximately 3 to 5 months. While this technique can be successful, it is more likely to fail in large breed dogs as the prosthetic ligament can stretch or rupture. Another common complication is over-tightening of the prosthetic ligament with applies excessive compression of the joint. This can lead to cartilage damage, increased risk of meniscal injury, limited range of motion of the joint, and discomfort.
This technique differs from the traditional extracapsular stabilization in that it is a bone to bone fixation and utilizes a method for more accurate isometric implant placement. FiberTape®, an implant designed specifically for ligament repair, has superior strength and stiffness compared to conventional materials used for extracapsular stabilization. The FiberTape® is passed through these tunnels. Toggle buttons are inserted and used to apply appropriate tension to the FiberTape® providing stabilization of the knee
Tibial Plateau Leveling Osteotomy (TPLO)
The TPLO procedure is a dynamic procedure and stabilizes the knee by leveling the tibial plateau. The surgeon will measure the tibial plateau angle (slope) from X Rays and accurately and precisely determine the amount of rotation that is needed to reduce the angle to between 5 and 8 degrees. The basis of the TPLO procedure is that the surgeon will make a curved cut (Osteotomy) in the tibia and rotate the segment so that the load-bearing surface of the tibia is between 5 to 8 degrees. A plate and screws is then applied to hold the tibia in this position and allow for the bone to heal. Recovery time following the TPLO procedure is approximately 2 to 3 months. Following TPLO surgery, patients use the limb and are more comfortable much sooner than following the Extracapsular Stabilization. Additionally, studies show that there is less arthritic development long term following the TPLO verses the Extracapsular Stabilization (Lazar T, Vet Surg, 2005).
Surgical correction is the only way to resolve a Luxating Patella. Corrective surgical techniques such as sulcoplasty, osteotomy, and desmotomy will be needed to realign the quadriceps mechanism and counteract the muscular forces pulling the patella in the wrong direction. Correction is possible in approximately 95% of cases.
Tibial Tuberosity Advancement (TTA)
The TTA is a dynamic procedure similar in principal to the TPLO but relies on the patellar tendon to stabilize the knee. This involves moving the patellar tendon forward to the point that it is perpendicular (at 90 degrees) to the tibial plateau with the limb in a standing angle. This movement relieves the load of the CCL, applying that load to the patellar tendon. The amount of distance necessary to advance the patellar tendon to make it perpendicular to the tibial plateau is measured from preoperative radiographs.
The patellar tendon is attached to the tibial tuberosity (the front top portion of the tibia) and it is the tibial tuberosity that is actually advanced.
The tibial tuberosity is cut in a wedge fashion and moved forward the predetermined amount. It is held in place by a titanium cage, fork and tension band plate. Bone grows over and through the cage and fills in between the tibia and the advanced tibial tuberosity. This technique is not appropriate for dogs with tibial slopes greater than 27° to 30°.