Anterior Cruciate Ligament Rupture
A ligament consists of tough, fibrous tissue connecting two bones. The cranial cruciate ligament stabilizes the bones of which meet in the knee. It prevents the tibia from sliding forward in relation to the femur. In the knee, rupture of the cranial cruciate ligament allows the femur (thighbone) to slide back and forth over the tibia (shinbone). This ligament may have abnormal stress on it due to your pet's conformation. The greater the stress on the ligament, the more likely it will be injured. The ligament is made up of multiple strands, similar to how tough ropes are made. The ligament may have a partial rupture, similar to how a rope might fray. The remaining tissues are then weaker, but have more stress upon them. The ligament may also suddenly be fully ruptured. This is frequently seen with larger active dogs when they may vigorously twist and turn in their play or work.
Normal stifle, view from front Ligament Rupture
Diagnosis is made by demonstration of laxity, radiographic appearance or imaging with CT scan or MRI. The laxity is palpated. Many times, the pet may need to be sedated to demonstrate this. Pain, fear or other reasons can make a pet tense up, preventing the joint to be properly manipulated. If diagnosis is delayed, fibrous and arthritic changes may prevent the diagnostic manipulation which normally helps with the diagnosis. Sedation allows the pet and their muscles to relax, and allow proper manipulations in nonfibrotic joints. If radiographed soon after injury, X-rays have characteristics that indicate injury in the area of the ligament.
If torn or ruptured, the joint has an abnormal laxity causing other tissues around the knee to be stressed, causing them to be stretched and used improperly. This causes pain then abnormal wear and tear of the joint, leading to arthritis. Once a joint is damaged or injured, the bones and joint tissues are very active in trying to compensate for injuries, but are not so capable. Unfortunately, the changes these tissues can make are not sufficient to keep the pet pain free. This is the reason the onset of arthritic changes occurs relatively fast. Arthritic changes will become evident surgically after only 1-2 weeks after a joint is damaged. Arthritis is progressive. As time goes on, it worsens to the point a joint may not support the animal's body weight, or is unable to be flexed or extended without pain. The sooner a repair can be made, the sooner the arthritis will be slowed down or potentially prevented. X-rays are taken just prior to surgical repair to help document arthritic changes that already exist.
Depending on the severity of the rupture, concurrent joint damage (meniscal injury, etc.), your pet's activity level, preexisting disease to the limb, and size of pet, treatment may consist of limited exercise and rest or surgical repair of the torn ligament. In general, the larger, younger, more active pets should have 'reconstructive' surgery also called geometry modifying techniques performed. Several surgical options are available. Tibial plateau leveling ostectomy (TPLO) and Tibial Tuberosity Advancement (TTA) are the most common geometry modifying techniques. Since the torn ligament is too small and compromised to be repaired, various techniques are utilized to stabilize the joint otherwise. The technique I offer is a lateral imbrication suture. This method has been used for years. I feel this technique is best reserved for dogs that are not expected to return to high athletic function. Again, the procedure selected will be based on your pet's needs. The goal of the surgery is to once again stabilize the joint. If surgery is completed relatively soon after the ligament was damaged, less arthritis will occur. However, even the most complete surgery will not completely prevent arthritis in the limb. Surgery should allow your pet to use the limb for a much longer period in relative comfort.
Initially following surgery, your pet will not be expected to bear weight on that limb for a period of several days, to several weeks, depending on the techniques used and individual surgeon and patient variations. It is important that the uninjured limb be healthy enough to bear the pet's weight. If obese, it is recommended the dog first lose weight to reduce the stress on the 'normal' limb. It is important to note that depending on how or why the stifle was injured, the 'normal' limb may be compromised also. It is not unusual for this limb to require treatment within a year of the first. If the first surgery is not completed a dog may not be able to walk, or may have great difficulty walking/moving about if both cruciates are ruptured. Recovery from surgery is also more difficult if there is not a normal limb to bear the weight during recovery.
Important Points in Treatment
1. Activity: It takes time for the surgically manipulated tissues to heal, and become functional. Even if your pet feels good, it is too early to allow activity. During this time, activity can cause tearing and other damage. Damage caused by activity at this time may not be readily repairable. Tranquilizers may be prescribed to help keep your pet quiet and inactive.
ACL Rupture Progression
The above radiographs and picture are of the same dog. The dog had a rupture of the right cranial (anterior) cruciate ligament (ACL). The repair was delayed for a full year. The radiographs on the right demonstrate the arthritic changes that occured. The surgical picture shows how the arthritis actually appeared. We can never remove the arthritis, but the joint has been surgically stabalized now and the patient is much more comfortable. In the above case the patient was grossly obese when the injury occured. He was a better candidate for surgical repair after his weight was brought into line.
Arthritis develops relatively fast after some ligament injuries. Even partial ACL tears cause an instability and leads to arthritic changes.
I enjoy surgery, including cruciate repair surgeries. For surgical cases I am uncomfortable with, or know there is an alternative repair available, I refer to veterinary board certified surgeons.
The following are the instructions I send home for post operative care. I may modify the instructions for each patient. These instructions are specific for my patients. Do not use these instructions for patients that have had surgery elsewhere. Always follow the instructions from your surgeon.
Your pet has had a surgical repair for a ruptured Anterior Cruciate Ligament. Recovery will take several months. During the initial phase, your pet may be non weight bearing on the limb for 2-3 weeks. Be sure to provide good footing (provide adequate traction/footing) for your pet to move around on without slipping. Stairs should be avoided or if necessary should have good traction to assist your pet. If steps must be used you should place a towel or other material under your pet's belly and hold on to help keep your pet from slipping or trying to use the repaired leg too soon.
Pets will benefit from physical therapy including cold compresses, massage and passive range of motion exercises. Apply a cold compress to the surgical site (make sure there is a towel between the skin and the compress) 4-5 times daily for the first 3-4 days. Each session should be 10-15 minutes.
Massaging the limb 4-6 times daily should be relaxing for the pet. The pet should actually like this and if is resistant please contact us. To massage your pet, start at an area away from the surgical site and apply mild pressure to the muscles of the area. Your pet should like this. If not, then let us know so we can help you. When your pet is relaxin with the massage that is away from the surgical site, move closer to the site gently massaging the muscles of the thigh and then the muscles lower leg muscles. Each session should last about 5 minutes of the muscles of the affected limb. This may be done before or after the cold compresses.
In addition to massage passive range of motion exercises (PROM) should be completed. PROM may be done just after the cold compresses and or just after massage. To do PROM your pet is best layed on his side with the surgery limb up. Start at the toes or hock (ankle) and gently grasping the limb above and below the joint you are working on and move your hands/arms to gently flex (bend) and extend (straighten) it which should require no force. If these joints are normal there should be no pain or resistance to this. Repeat this 6-12 times for each joint area. Do not force any bending or straightening of the joints.
After doing the toes and/or hock you may start on the stifle (knee) with the same motions. Your pet should let you know if this seems painful, and do not continue if it is, but contact us. If your pet seems to enjoy this the first few times on the stifle only repeat the flexing and extending 6 times, then as days go by add more repetitions. As days go by the amount of flexion and extention should increase to a full normal ROM. Repeat this activity 4-6 times daily until your pet is using the leg well on the walks.
Your pet should also be kept from moving at a pace faster than a walk for the next 2 weeks which normally means they need to be crated or leashed. They should not be allowed activity other than enough to allow urination and defecation and that should be done while controlled on a 4-6 foot leash. You can crate your pet, or keep a short leash on them to prevent them from moving fast.
After 2 weeks, you may allow your pet to move around more, and you must start them on leash walks for their physical therapy. Start walking with a slow 1/4 mile walk daily. We want the pet to move slowly enough so he will be stimulated to place the foot and bear weight. If he is moving too fast he will not properly bear weight and will not properly recover from the surgery. Walks should be increased by 1/4 mile every 3-4 days as desired and depending upon the pet's progress. During the first 2 weeks of leash walking the pet may be allowed to move about his normal home but should not be allowed to move faster than a walk. That may mean continued leashing. Please call if you have any questions.
Please call if your pet is not bearing weight or progressing. After 2-3 weeks your pet should be at least toe touching on the limb. Please call if he/she is not. After 3-4 weeks, the pet should be bearing weight and walking relatively normally. At this point the pet can have activity in the normal home environment off leash. After 4-8 weeks the pet should be walking normally. Once the pet is walking 2 miles daily with no lameness, they should be allowed up to 10 minutes free play daily for 7 days, if no lameness, the free play can be increased every 7 days by 10 minutes till they can play, using the leg well for an hour. If they again become to favor the leg, then the play sessions should be stopped or shortened and/or decreased in activity level.
Pets with problems on the contralateral limbs may start to bear weight better on the corrected limb earlier.
Recovery from this orthopedic surgery will be painful without use of pain medications. Recovery will be delayed if adequate pain controll is not provided. We have provided medications to help reduce/control pain. The medications are also used to reduce inflammation and helps the pet's joint heal well. It is important that your pet be given these medications. Some of the medications for pain can cause some drowsiness. If your pet seems painful or too drowsy to you, please call, we may need to adjust medications. We do not want your pet to hurt.
Other forms of physical therapy are available through controlled hydrotherapy, and/or through acupuncture. Pets that are not progressing well should have additonal physical therapy and we will help determine what that is. We offer acupuncture and can refer you to a hydrotherapy service at your request.