Category: Advanced Surgery Info

Care of the incision:

You should monitor your pet’s incision at least once daily for evidence of infection. Infection generally appears as a painful red swelling associated with the incision. Other incisional problems include separation of the incision line. This is most commonly associated with infection or a pet licking or chewing at the incision. If you see your pet chewing at the incision he/she will need to wear an Elizabethan (a.k.a. lampshade) collar until the sutures or staples are taken out. Sutures are generally taken out around 2 weeks following the surgery.

Activity restriction:

Following surgery your animal will need to be confined to a crate or small room for 8 weeks. Slippery floors such as hardwood and ceramic tile should be avoided. Your pet should not be allowed to play with other animals or children and should be kept away from stairs. He or she should be taken outside 4 to 5 times per day to urinate and defecate. Your pet should be on a leash at all times when outside for at least 8 weeks.

Physical therapy:

Physical therapy following surgery for patellar luxation repair consists of massage and performing range of motion, as well as knowing when to start activities to encourage your pet to use the affected limb properly. Most dogs will place significant weight on the operated leg within 5-6 days of surgery. If your pet is not using the leg within 7-10 days post surgery then you should more closely follow the suggested range of motion exercises with him/her at least 3 times per day on the operated knee. Your veterinarian can instruct you about the specifics of physical therapy if indicated.

Recheck examinations:

Rechecks are generally scheduled for 2 weeks following surgery for suture removal and 6-8 weeks for final recheck examination. Xrays may be taken at specific intervals to evaluate healing. If your pet is doing well at that time no additional rechecks will be needed.

Medications:

Your veterinarian will provide you with instructions about medications to be taken following knee surgery. Generally some type of pain medication will be administered for 5 to 7 days following surgery.

General care:

Following any surgery you should also be sure that your pet is eating and drinking normally without vomiting, diarrhea or prolonged anorexia. You should also be aware of your pet’s general attitude and make sure that he or she interacts normally with your family members, is able to sleep normally and is not unusually lethargic. If you notice anything significantly out of the normal in reference to the above habits you should contact your veterinarian.

After surgery is completed, the affected leg(s) may be bandaged for three to seven days. Passive physical therapy is begun immediately after bandage removal to work out the stiffness and reestablish a normal range of motion in the joint. During the next three to four weeks, light walking around the house or supervised short walks outside must be strictly controlled until a progressive building of muscular support and stamina leads to unrestricted normal function.

Your pet must be kept in a confined area such as a small room, dog run, or kennel for the first 4 weeks following knee surgery. This confinement is essential to prevent your pet from damaging the repair caused by excessive activity such as running through the house and slipping on the tile/linoleum, when your pet sees a squirrel outside or when the doorbell rings. After this period of time, your pet needs to be kept on restricted activity for the next two months.

During this period of restricted activity he/she should still be confined to a small area, however slow, controlled leash walks are permitted. This restriction will allow sufficient time for the surgical site to heal completely. Tranquilizers may be necessary to help keep your pet quiet. Your pet may develop a tolerance to these drugs, however, necessitating progressively higher doses to effect the desired level of tranquilization. Only enough tranquilization to “take the edge off” for your pet and make them happy to walk rather than run is necessary. These drugs are not harmful or addictive to your pet in any way. No off-leash activity should be allowed for at least 10 weeks following surgery.

If a bandage is placed on your pet’s leg, it should be kept clean and dry. If there is a chance that the bandage will come in contact with water or moisture, you should cover the bandage with a plastic bag. Do not leave the plastic bag on your pet’s leg for a prolonged period of time however, or it will cause moisture accumulation and skin infection underneath the bandage! If your pet’s toes are exposed at the bottom of the bandage, please check them daily for any signs of swelling. If they should become cool and/or puffy, the bandage may be impeding circulation and should be changed immediately. If this should occur, please contact us.

If your pet’s toes are not exposed, pinch them through the bandage until your pet reacts to let you know he still has feeling in them. Due to your pet’s normal activity, the top may loosen and the incision site may become exposed. This is okay as long as your pet does not lick or chew at the incision area, the bandage still offers support to the knee, and you are still able to check your pet’s toes. If the incision area looks as though it needs to be cleaned, please clean the incision with witch hazel, and apply an antibiotic ointment to it if you wish.

If you find that your pet is having difficulty in rising and/or walking with the bandage on, we suggest that you use a towel placed around the stomach to act as a sling for the hind quarters. Lift your pet gently and support the rear limbs while it walks. We would be happy to show you how this is done. You can also purchase a premade sling from a pet store or online if you prefer.

Your pet may require a lot of patience and attention during this recovery period. Your biggest chore will be to keep your pet confined and inactive for a three month period. If you have any questions or if you need help and/or suggestions, please do not hesitate to contact our office.

Overall, some pets recover very quickly with little need for owners’ assistance, but other animals need intensive physical therapy. Lean and fit animals tend to recover quicker than overweight and weaker pets.

The diagnosis of patellar luxation is essentially based on palpation of an unstable kneecap on orthopedic examination. Additional tests are usually required to diagnose conditions often associated with patellar luxation and help the surgeon recommend the most appropriate treatment for your pet.

These may include:

• Palpation of the knee under sedation to assess damage to ligaments
• Radiographs of the pelvis, knee and occasionally tibias to evaluate the shape of the bones in the rear leg and rule out hip dysplasia
• 3-dimensional computed tomography to provide an image of the skeleton of the entire rear legs. This advanced imaging technique helps the surgeon plan surgery in cases where the shape of the femur or tibia needs to be corrected.



Because there is great individual variation in the pathologic deformities seen, a graded classification of medial patellar luxation (Putnam 1968) has been formulated as a basis for recommending which type of surgical repair is most appropriate for each individual.

Surgical treatment is typically considered in grades 2 and over. While the grading system is useful in communicating the degree of patellar luxation, the anatomical abnormalities that might be present to produce the degree of luxation, which patients may require surgery at some point, and in suggesting the prognosis for surgical patients, there is a danger in reading too much into the classification system. For example, one cannot base recommendations for surgical repair solely on the grade of luxation present, because the correlation between the grade of luxation and the clinical signs is not strong.

Many Grade 1 small dogs will never encounter lameness problems; however, others, especially many large breed dogs, will be clinically affected. On the other hand, nearly all Grade 3 and 4 dogs will show signs of lameness and disability. However, these signs are not always severe and, perhaps more importantly, some owners may not view the problem as significant in the context of the limited physical demands placed on their dogs, especially in the case of the small breeds.

GRADE I

The anatomic alignment of the stifle is normal with the patella luxating only when pushed out of the socket.

GRADE II

The patella is returned by manual pressure.

GRADE III

The patella is permanently dislocated but can be reduced manually with the limb extended.

GRADE IV

The patella is permanently dislocated and cannot be manually reduced. In dogs with grade IV patellar luxation more aggressive surgery is often required. This involves straightening of the femur and/or tibia with complete bone cuts (a.k.a. osteotomies) and stabilizing the bones with bone plates. Lateral patellar luxation, or LPL, is less common than MPL and occurs when the kneecap occasionally rides on the outside of its normal groove. It, too, can be congenital or acquired, with the congenital form again being more common. While it can occur in any dog, it is more common in large and giant breeds. LPL is frequently accompanied by malformation of the femur and/or tibia. The disease can produce marked lameness and progress to crippling arthritis. Because of the accompanying bony malformations, extensive surgery may be required to correct this problem.

Patellar luxations that do not cause any clinical sign should be monitored but do not typically warrant surgical correction, especially in small dogs. Surgery is considered in grades 2 and over. Surgical treatment of patellar luxation is more difficult in large breed dogs, especially when combined with cranial cruciate disease, hip dysplasia or angulation of the long bones. One or several of the following strategies may be required to correct patellar luxation: Reconstruction of soft tissues surrounding the knee cap to loosen the side toward which the patella is riding and tighten the opposite side.

Lateral Imbrication

This procedure alone may be adequate for a mild case but is often used as an adjunctive procedure to supplement one of the other surgeries. When the patella slips out of its groove, the joint capsule surrounding it is stretched to allow this motion. Imbrication simply involves taking a tuck in the joint capsule. The tightened joint capsule does not allow for the slipping of the kneecap and the kneecap is confined to its proper groove.

Trochleoplasty

Deepening of the trochlear groove, or trochleoplasty, can be accomplished with a variety of techniques. A chondroplasty technique involves cutting out a taco-shaped wedge of cartilage, removing a small portion of bone beneath it, and then replacing the cartilage. The result is a deeper groove. This procedure can only be performed on very young dogs, because their cartilage is thicker.

Trochlear recession involves cutting out the cartilage and bone in such a way as to create a deeper trough. This trough will then fill in with scar tissue over time. Because this scar tissue is not as good as cartilage for joint function, this technique has given way to others that attempt to preserve normal cartilage. It can, however, be useful in carefully selected cases.

Wedge recession creates a taco-shaped piece of cartilage and underlying bone. Then, the bone below the wedge is removed and the wedge is replaced, forming a deeper groove. Block recession is identical in principle to wedge recession, except that a rectangular piece of cartilage and bone, rather than a wedge, is removed.

Tibial Tuberosity Transposition

The kneecap attaches to the lower leg via its patellar tendon at a bony site called the tibial tuberosity. Many times this site forms abnormally on the inside, as with MPL, or on the outside, as with LPL. In this procedure, the surgeon fractures the tibial tuberosity and moves the tibial tuberosity back into proper alignment and secures it in place with a pin and or wire. Realigning the joint, kneecap, and tendon prevents dislocation from reoccurring.

Are there any potential complications associated with surgery?

Any surgical procedure has the potential for complications. Fortunately, surgery for a patellar luxation is commonly performed and complications are rare. Potential complications include problems with general anesthesia, surgical infection, migration of the surgical implants (i.e. pins that stabilize the tibial tuberosity transposition) associated with the repair, complete disruption of the tibial crest, rarely patellar tendon rupture and failure of the surgery to completely stabilize the patella and resolve lameness.

Greater than 90% of dogs with surgical repair of grade 1, 2 and 3 patellar luxations will not have any significant complications and will return to normal or near normal function with surgery. If pins had to be used to transpose the tibial crest, these may need to be removed in 3-12 months. Some dogs “allergic” to the metal. Ultimate results will depend on the amount of arthritis existing prior to surgery and/or the severity of the patellar luxation.

Patellar luxation is one of the most common congenital anomalies in dogs, diagnosed in 7% of puppies. The condition affects primarily small dogs, especially breeds such as Boston Terrier, Chihuahua, Pomeranian, Miniature Poodle and Yorkshire Terrier. The incidence in large breed dogs has been on the rise over the past ten years, and breeds such as Chinese Shar Pei, flat-coated retriever, Akita and Great Pyrenees are now considered predisposed to this disease. Patellar luxation affects both knees in 50% of all cases, resulting in discomfort and loss of function.

Intermittent or consistent lameness; bowlegged stance; reluctance to walk or jump; occasionally holding a rear leg out to the side when walking.

Lameness that is often intermittent, and may be unilateral or bilateral; thick, swollen stifles; pain on range-of-motion; crepitus; palpable luxation; inability to jump or walk normally; medial displacement of quadriceps muscle group; lateral bowing of the distal third of the femur.

Clinical signs associated with patellar luxation vary greatly with the severity of the disease: this condition may be an incidental finding detected by your veterinarian on a routine physical examination or may cause your pet to carry the affected limb up all the time. Most dogs affected by this disease will suddenly carry the limb up for a few steps, and may be seen shaking or extending the leg prior to regaining its full use.

As the disease progresses in duration and severity, this lameness becomes more frequent and eventually becomes continuous. In young puppies with severe medial patellar luxation, the rear legs often present a “bow-legged” appearance that worsens with growth. Large breed dogs with lateral patellar luxation may have a “knocked-in knee” appearance, combining severe lateral patellar luxation and hip dysplasia.

Causes of Patellar Luxation

Patellar luxation occasionally results from a traumatic injury to the knee, causing sudden non-weight-bearing lameness of the limb. It may also develop subsequent to cranial cruciate deficiency in dogs that will typically have a chronic history of lameness. However, the cause remains unclear in the majority of dogs. The femoral groove into which the kneecap normally rides is commonly shallow or absent in dogs with non–traumatic patellar luxation.

Early diagnosis of bilateral disease in the absence of trauma and breed predisposition supports the concept of patellar luxation resulting from a congenital or developmental misalignment of the entire extensor mechanism. Congenital patellar luxation is therefore no longer considered an isolated disease of the knee, but rather a component/consequence of a complex skeletal anomaly affecting the overall alignment of the limb, including:

• Abnormal conformation of the hip joint, such as hip dysplasia
• Malformation of the femur, with angulation and torsion
• Malformation of the tibia
• Deviation of the tibial crest, the bony prominence onto which the patella tendon attaches below the knee
• Tightness/atrophy of the quadriceps muscles, acting as a bowstring
• A patellar ligament that may be too long

The patella, or kneecap, is a small bone buried in the tendon of the extensor muscles (the quadriceps muscles) of the thigh. The patella normally rides in a femoral groove within the stifle. The patellar tendon attaches on the tibial crest, a bony prominence located on the tibia, just below the knee. The quadriceps muscle, the patella and its tendon from the “extensor mechanism” and are normally well-aligned with each other. Patellar luxation is a condition where the knee cap rides outside the femoral groove when the stifle is flexed. It can be further characterized as medial or lateral, depending on whether the knee cap rides on the inner or on the outer aspect of the stifle.

When the patella is in its normal position, its cartilage surface glides smoothly and painlessly along the cartilage surface of the trochlear groove with little or no discomfort.

As the patella “pops out” of its groove these cartilage surfaces improperly rub each other. The animal may cry and try to straighten (extend) the leg to “pop it back in” or may hold the limb up until muscle relaxation allows the kneecap to reposition itself. This resembles an intermittent lameness.

There is little or no discomfort until the cartilage is effectively “rubbed off” or eroded to a point where bone touches bone. From this point on, each time the patella “pops out” into its abnormal, luxated position it will cause pain. This explains why many individuals have no clinical lameness until they reach adulthood. Often progressive cartilage wear creates an acutely painful condition.

Success Rate

Currently the success rate of either surgery is between 85-90%. This means your pet should get back to normal or near normal activity over a 2-4 month period. There are a small percentage of dogs and cats that do not do well following cruciate ligament injury, no matter how they are treated.

Anesthesia

There is always a risk with anesthesia although it is rare that significant problems are encountered if the pet has been thoroughly evaluated prior to surgery. All animals anesthetized are continuously monitored by a veterinary nurse throughout the procedure. They are placed on intravenous fluids and their heart rates, respiratory rates and blood pressure are constantly monitored. They are also placed on a circulating warm water blanket to help maintain their body temperature under anesthesia.

Infection

There is always the potential for infection with any surgery. In most cases infection occurs when the animal licks or chews at the surgical incision postoperatively. That is why we send your pet home with a protective collar that they should wear at all times to prevent them licking or chewing at the incision. With either surgery- if an infection develops it can delay healing and necessitate the removal of the implants (the stabilizing Nylon suture or the bone plate and screws), which is additional anesthesia and surgery for your pet and additional cost.

Implant failure

Premature breakdown of the stabilizing Nylon suture can occur and is more likely in very large, active dogs or obese dogs, which is why it is recommended that dogs over 70 pounds are suggested to have TTA procedures. It is also more likely if dogs do not have their activity restricted as directed postoperatively. If the Nylon suture breaks prematurely it can lengthen the recovery process and in some cases necessitate further surgery.

The bone plate and screws used in the TTA are very strong but by cutting the bone – this is essentially the same as having a fractured bone that requires time to heal. Initially the strength of the repair is provided by the plate and screws alone. Over the next few weeks, as the bone begins to heal, the bone starts providing additional strength to the repair. It is rare that we have implant failure with this technique but if the plate or screws break, the plate pulls off the bone, or the bone breaks around the screws further surgery is required and it can be very difficult to perform this additional repair. This is why it is crucial to follow the take home instructions for proper rest and rehabilitation.

Isolated meniscal injury

As previously stated, dogs do have a slight risk of developing an isolated meniscal injury in the future, requiring re-exploration of the joint. This can occur with either the lateral suture technique or the TTA and it is not possible to predict which dogs will be affected.

Fabella Pain

This is a potential complication of the lateral suture stabilization technique. The fabella is a small bone at the back of the dog’s knee that the Nylon stabilizing suture is placed around. In a very small percentage of dogs this can cause some discomfort and occasionally we need to remove it under a very short anesthesia.

Tibial Tuberosity fracture (fracture through the top, front part of the tibia or shin bone)

This is a rare complication of the TTA procedure. It occurs very infrequently and is most often secondary to the pet being too active postoperatively. It may require placement of metal pins to repair the damaged piece of bone.

Persistent Lameness secondary to osteoarthritis

This affects between 10-15% of dogs. This is a potential complication with either surgery and there is no way to predict which dogs will have significant problems with arthritic pain. It requires life-long activity moderation (less free running and jumping, more slow leash walks and swimming) and the use of non-steroidal anti-inflammatory drugs long term (drugs such as Rimadyl, Deramaxx, Metacam Galliprant and Previcox).

Specific instructions will be given at the time your pet is discharged from the hospital including what medications to give (antibiotics and pain medications). In general animals come back in 10-14 days to have their incisions checked and the skin sutures or staples removed. The stability and comfort of the joint will be checked at this visit. Following surgery your pet will require strict activity restriction. Patient activity is generally restricted for at least 2 ½ to 3 months.

Postoperative Instructions

For the first 10-14 days your dog should be confined to a crate or small room with minimal furniture. Steps should be kept to a minimum. They should go outside on a short leash, no longer than 3 feet (not at the end of an extendible leash) to go to the bathroom only – no free running, jumping or playing is allowed. This can result in failure of the implants and may result in the need for more surgery.

If your dog will tolerate it you can apply an ice pack to the incision up to 4 times daily for 10-20 minutes for the first 3-5 days. Do not try to force this if your dog will not let you. Once the skin sutures have been removed in 2 weeks you can start the following walking program at home – all other restrictions still apply and your dog should still not be allowed to roam free in the house: Week 3 post operatively: Slow, on a short leash walks for 5 minutes up to 3-4 times daily. You can also start making your dog walk in some small circles and figures of 8 with the operated leg on the inside of the circle/8.
Week 4 postoperatively: Slow, on a short leash walks for 10 minutes up to 3-4 times daily.
Week 5 postoperatively: Slow, on a short leash walks for 15 minutes up to 3-4 times daily.
Week 6 postoperatively: Slow, on a short leash walks for 20 minutes up to 3-4 times daily.

For dogs that have had a TTA, weeks 7 and 8 should be the same as week 6: Slow, on a short leash walks for 20 minutes up to 3-4 times daily.

If your dog is hard to control on the leash and is liable to injure themselves their activity should be completely restricted to leash walks to the bathroom only for the first 6 weeks. Following the lateral suture surgery dogs are then seen for a recheck at 6 weeks; further activity instructions will be given at this visit. For dogs that have had a TTA, follow-up x-rays will be needed to assess healing at 8 and 12 weeks postoperatively. There is an additional charge for these x-rays and sedation for at least the 8 week xrays,. Additional X-rays may be taken in 2 weeks if the 12 week radiographs do not show complete healing. Dogs that have had a lateral suture stabilization do not require follow-up x-rays in most cases.

All pets with stifle problems should maintain an ideal body weight and you may need to decrease the amount you are feeding during the postoperative recovery period.

The amount of arthritis that an animal develops after cruciate ligament injury is variable and there is no way to predict how it will affect your pet. It is important that once they have healed from surgery they have regular exercise, maintain an ideal body weight and, if possible, stay on a Hyaluronic Acid and Glucosamine/Chondroitin joint supplement for life.

In addition, some animals may require the tactical use of non-steroidal anti-inflammatory drugs such as Rimadyl, Deramaxx, Previcox Galiprant or Metacam. These can be obtained from your regular veterinarian and be used on an “as needed” basis. Arthritis tends to cause more discomfort after periods of sudden very heavy exercise (free running, jumping, ball chasing) and when the weather is cold and damp.