Anatomy
The knee joint (or stifle) has a number of important parts illustrated below: 

Rupture of the Cranial Cruciate Ligament
In many dogs, the cause of CCL rupture is unknown.  It often appears to involve premature degeneration of the ligament and/or abnormal alignment of the knee bones.  Occasionally a traumatic event or vigorous exercise precedes rupture but many dogs “seem fine one minute and lame the next”.  Whatever the cause, rupture results in instability, pain, lameness, joint swelling and eventually arthritis.

Diagnosis
Diagnosis is made by examination of the knee joint and identifying instability.  Sometimes sedation or anesthesia is required to make a definitive diagnosis.  Occasionally, findings on X-Rays are utilized to support suspicion of CCL rupture and to rule-out other causes of hind leg lameness.

Treatment
Initial treatment is usually rest and anti-inflammatory medications.  Most smaller dogs, those weighing less than 35 lbs, do very well with rest and anti-inflammatory medication. However, most dogs weighing greater than 35 lbs (and some less than 35 lbs) require surgery to have a satisfactory outcome.  As a general rule, if a pet remains lame, or again becomes lame, after 2-4 weeks of initial treatment, surgery will eventually be necessary. 

Important Facts:

• Most dogs weighing more than 35 lbs (and some less than 35 lbs) need surgery for satisfactory outcome.
• A successful outcome with surgery is expected in 90-95% of cases.
• Regardless of the treatment, some arthritis will develop in the knee.
• General anesthesia is utilized for the procedure 
• The faint scar remaining after surgery usually becomes covered with fur again.
• An overnight stay is required so discomfort can be controlled with injectable pain medication.

• Relieve pain associated with the ligament injury.
• Stabilize the knee joint in a more anatomically correct position
• Decrease the amount of arthritis which will inevitably develop in the knee.
• Limit stress put on the opposite limb and other limbs and joints.

• Many different procedures exist for the stabilization of the knee joint.
• No procedure has been shown to be superior to the others over the long term.
• The ligament itself is typically too damaged to be repaired or replaced

• Exploration of the joint to confirm the diagnosis and identify the extent of damage.
• Removal of damaged ligament and cartilage.
• Stabilization of the knee joint with a thick nylon suture or artificial ligament.  The suture is placed around the fabella and through the tibia.

The Recovery:

• The recuperative period typically lasts for a total of 8-12 weeks.
• Pets gradually begin to put weight on the operated leg over the first 14 days.
• Physical therapy comes in the form of progressively longer leash walks over the following weeks.

• Initially, exercise is limited to walks to eliminate only.
• Skin sutures are removed 10-14 days after surgery.
• Exercise on leash is gradually increased over the following weeks; swimming is also excellent exercise.
• Pain medication and antibiotics are administered for several days after surgery.
• No running, jumping or playing is permitted for at least 12 weeks following surgery.

Outcomes, Complications, and Risks:

• Most pets are permitted to resume normal activity several months after surgery.
• As many as 30% of dogs will require surgery on the opposite knee in the future.
• 5-10% of dogs have lameness after surgery which is controlled with medication.
• Rarely …the artificial ligament needs to be removed or replaced …infection after surgery makes additional surgery (or even amputation) necessary

Cost of the Procedure:

• This typically includes examination, pre-anesthetic bloodwork, anesthesia, surgery, hospital care, post-operative medications, and two follow-up examinations.
• Please ask your veterinarian for a detailed surgical estimate for your pet.