Extracapsular Surgery


Anatomy of the knee

  • There are two cruciate ligaments which cross inside the knee joint: the anterior (cranial) cruciate and the posterior (caudal) cruciate.
  • The anterior cruciate stabilizes the knee by preventing the tibia from slipping forward and out from under the femur.
  • There are two collateral ligaments that stabilize the knee in a side-to-side direction.
  • There are two c-shaped cartilage structures (meniscus) that cushion and stabilize the knee by fitting between the femur and tibia.


Anterior (Cranial) Cruciate Ligament Rupture

  • ACL rupture is the most common orthopedic condition that we treat. The cause is unknown, but conformation of the limbs and genetics may play a role.
  • All breeds of dogs, cats and ferrets can be affected, but some breeds such as Labrador Retrievers, Rottweiler, and Mastiffs are more predisposed.
  • Ligament rupture is usually the result of a gradual process, not due to a single traumatic injury.
  • Symptoms may begin after sudden stopping, twisting, or over extension of the knee during exercise.
  • Many animals have a predisposing factor like age-related ligament degeneration, pre-existing inflammation, anatomical abnormalities or abnormal slope of the plateau of the tibia bone.
  • About 33-50% of dogs that have an abnormal cruciate ligament (ACL) will develop a partial or full rupture of the opposite ACL.

How do we diagnose an ACL injury?

  • The doctor will perform a physical exam and check for 'drawer motion' and pain in the knee. If the ACL has torn, the doctor may be able to slide the knee joint like a drawer; a normal knee does not slide in this way. There are other physical manipulations of the knee that can be done to aid in the diagnosis of ligament injuries.
  • X-rays may be taken to look for excessive fluid build-up in the joint, signs of arthritis or any other problems that may be affecting the knee.

Is there anything that can be done to fix an ACL injury?

It is unusual for lameness to resolve without surgery, especially in large breeds. We use one of two surgical procedures to correct this problem:


Extracapsular Repair
Extracapsular Surgery

  • The knee joint is first inspected via a small incision (arthrotomy) or insertion of a camera (arthroscopy). The torn remnants of the ACL are removed and the meniscal (diagram) structures are examined. If the meniscus is torn, the damaged portion is removed.
  • A strong, non-absorbable suture (nylon band) is passed around a small bone on the back of the knee and then placed through a small hole made in the front of the tibia bone. The suture is then tightened which serves to prevent drawer motion, effectively taking over the job of the torn cruciate ligament.
  • Over time, scar tissue will form around the suture which helps to stabilize the joint.
  • This technique is most commonly used in small dogs and cats.
  • About 85% of patients show a significant improvement after surgery and are able to resume pre-injury activities.

Risks and Complications

  • Anesthesia complications can occur, but these are minimized by our high quality surgical facility.
  • The nylon band can break or loosen from its attachment behind the knee. This most often occurs when pets are too active during the early healing period (4-6 weeks from surgery).
  • Infection at the surgical site. This is minimized by proper sterile technique, peri-operative antibiotic usage, and prevention of licking of the incision.
  • If meniscal cartilage was not damaged at the time of surgery, there is a small chance that it may become damaged at a later date requiring a second surgery.

Arthritis and ACL Injury

  • Unfortunately we cannot stop or reverse the arthritis and degeneration of the joint, but surgery can help to slow its progression.
  • If your pet has arthritis in any joint, you may notice stiffness in the morning, lameness after heavy exercise or during weather changes.
  • We recommend that you help your pet by keeping them at a healthy weight, maintaining a regular amount of mild exercise, and giving a high quality glucosamine and chondroitin product.

Home-care Instructions for Extracapsular ACL Repair

  1. Keep the rest restricted from excessive activity for the next 6 week. No running, jumping or rough play with other pets during this time. No unsupervised time outside for the first 6 weeks.
  2. Utilize the E-collar or inflatable collar to prevent licking and/or chewing of the incision.
  3. Applying a cold pack to the XXXX knee (5-10 minutes daily) will help to reduce inflamation.
  4. Short, slow, leashed walks (5 minutes) twice daily.
  5. Medications have been dispensed. Please follow the directions
  6. Recheck appointments are nexessary at the following times:

a) 10-14 days for a suture removal.

b) 4 weeks for limb usage evaluation.

c) 6 weeks for limb usage evaluation. A rehabilitation protocol has been attached for specific

Physical Therapy for Extracapsular ACL Repair

What are the benefits of physical therapy?

Benefits include:

  • Increased blood flow to the affected area.
  • Prevention of joint contraction
  • Prevention or decrease in muscle atrophy
  • Faster return of use of the affected limb.

What does physical therapy involve?

We recommend a combination of actions as follows:

  1. Cold packs will minimize post-operative swelling and pain. Never apply the cold pack directly to the skin as it could result in cell damage. For the first 72 hours after surgery, the cold pack should be wrapped in a towel and then applied to the area 2-3 times a day for 5 to 10 minutes each time.
  2. Moist heat application will help increase blood flow to the area and relax tense muscles. We recommend using a clean washcloth moistened with warm water - starting 72 hours after surgery, heat should be applied 2-3 times a day for a period of10 to 20 minutes each time.
  3. (Click to see video)

    Video provided by: Dennis Caywood DVM, MS, DACVS, CCRT
    Senior Veterinary Specialist- Surgery/Rehabilitation

    Massage will improve blood and lymphatic flow to the area, which increases available nutrients to an area and promotes waste products and fluid removal. Massage also aids muscle relaxation. The muscles are grasped between the thumb and index finger and gently elevated. The tissues are then compressed alternately between the fingers of one hand and the heel of the other hand. Massage should be firm. Perform for 5 to 10 minutes every day.
  4. Passive Range of Motion (PROM) is very important in the prevention of tissue adhesions, promotion of normal joint movement, enhancement of blood and lymphatic flow, and prevention of muscle and joint contracture. Usually, this mode of therapy may be started after sutures are removed. Hands-on instruction by one of our staff members will be given to you before PROM therapy is attempted at home.
  1. Exercise. Specific instructions regarding exercise will be covered on your pet’s take home instructions, depending on the type of surgery they had. It is very important to follow these instructions regarding restricted activity to ensure the success of the surgery.

Extracapsular Surgery Rehabilitation Protocol

Short, leash walks are encouraged during the first six weeks. This activity will increase muscle stimulation and improve range of motion. Walks are to be done on a short leash and at a very slow pace. Use of extended leads is discouraged.

<Week One:

  • Begin with 5-10 minute walks three times daily, followed by an ice-pack (package of frozen peas wrapped in a towel) on knee for 5-10 minutes.
  • Massage the thight muscles for 5-10 minutes daily.
  • Flex and extend the knee 10-20 times twice daily.

Weeks Two and Three:

  • Increase walks to 10-20 minutes three times daily, followed by an ice-pack (package of frozen peas wrapped in a towel) on knee for 5-10 minutes if swelling is still present.
  • Continue massage the thight muscles for 5-10 minutes daily.
  • Flex and extend the knee 10-20 times twice daily.

Weeks Four and Five:

  • Leash walks may be increased to 20-30 minutes two to three times daily. While walking, gently nudge your dog sideways.>
  • Sit/stand 10 repetitions three times daily.
  • Figure 8 walks or circling to the left and right 10 times daily.
  • If your dog is doing well, “dance” with him/her. Hold up the front legs to encourage walking on the hind legs.
  • If your dog is not putting weight on the operated leg, the rehabilitation specialist will give you suggestions.

Weeks Six through Eight:

  • Leash walks 30-40 minutes two to three times daily, including inclines, hills, and ramps.
  • He/she may now begin to go up and down stairs slowly.
  • Tug-of-war.

The basic rehabilitation theme is a slow, gradual return to activity. The thigh muscles will still be weak even after the bone has healed. It often takes 3-6 months after surgery for the muscles to regain their pre-injury strength.

Frequently Asked Questions About Extracapsular Repairs

Does my pet have to spend the night in the hospital?

Orthopedic surgery patients are kept overnight for several reasons. Epidural anesthesia is given to keep your pet comfortable, but makes them unable to walk without assistance. Your pet will also continue to receive IV antibiotics and pain medication.

What can I expect after surgery?

  • 24 hours after surgery most dogs will be non-weight bearing to toe touching when walking.
  • 5 to 7 days post op — most patients will be bearing some weight on the limb.
  • 2 weeks post op — a moderate of amount of weight bearing is expected.
  • 6-8 weeks — mild lameness may be present.
  • Partial tear patients tend to recover more quickly.

Will my dog experience pain in the postoperative period?

We take pain control very seriously. Your pet will receive pain medication before surgery, epidural anesthesia during the procedure and continue on IV pain medication throughout the evening of surgery. Pain medication will be sent home as well.