AKA RCCL, CCL Tear, ACL Tear Extracapsular Surgical Repair

Rupture or injury of the cranial cruciate ligament in dogs is touted as the most common orthopedic injury treated by veterinarians. This is not a new disease or syndrome as some may speculate. In fact, the earliest veterinary report of cranial cruciate ligament injury that I have found was dated 1926. Veterinarians (and human physicians) have been attempting repair or treatment of these injuries ever since. Over the years many various methods for surgical repair of injured cruciate ligaments have evolved. These repairs include everything from ligament grafting and prosthetic device implantation to cutting the bones to change their anatomical alignment.

Some methods of repair are simply not suitable to the canine patient and others have fallen out of “vogue” as newer methods have proven to provide a better outcome. Primary or direct repair by suturing the torn ends is not feasible in dogs. The ability of the canine cruciate ligament to heal directly is very limited and degeneration usually occurs.

The following discussion details the repair of a ruptured cranial cruciate ligament using the lateral fabellar suture stabilization or extracapsular method. If your pet has been diagnosed with a ruptured or torn cruciate ligament please speak to your veterinarian about treatment options – this report is not meant to diagnose ligament injuries or be a recommendation for one treatment over another.

Rupture of the CCL occurs more often in larger breed dogs than toy or smaller breeds, and much much more often in dogs than cats. However, cruciate ligament injuries have been diagnosed in almost every size dog and even cats. I have also seen reports that maintain females have a higher incidence of CCL injuries than males. As of the time I am writing this article this theory hasn’t borne out in my practice as there seems to be a higher incidence of males than females.

The actual tearing is commonly associated with trauma, and sometimes an owner will witness the actual event occur. The dog will typically be running and playing (or leaping onto or off of the sofa or bed) and immediately start limping. The limp can be severe enough that the dog refuses to place the limb and bear weight, but most often the dog will bear some weight with a significant limp (lame enough for the untrained eye).

If I had to pick out one salient risk factor for CCL rupture in our practice it would have to be over-weight large breed dogs. The typical patient we see with CCL injuries is at least 10lbs over-weight, usually athletic (rambunctious), and has a straight legged appearance through the stifle and hock. Obviously not all over-weight dogs will suffer a CCL tear and not all dogs with ruptured CCLs are over-weight, but I see this combination so frequently that I cringe in anticipation of future injuries when I see young over-weight relatively straight legged dogs. One of the really difficult parts of this job is trying to make owners understand how important weight control really is to the health of their pet. Those extra treats may seem like a loving gesture but over feeding is a serious issue in our practice. (Okay, I’ll get down from the pulpit now.)

Cruciate ligament tears are generally diagnosed through a series of different symptoms, examinations, and diagnostics imaging procedures. The first indication of cruciate injury is generally a limp. The affected animal most often is either holding the limb up and is unable to comfortably bear weight or is only minimally bearing weight on the affected leg. Your veterinarian will then examine the affected limb and may take x-rays. If the diagnosis is difficult to make based on these results an MRI or arthroscopic surgery may provide the necessary diagnosis.

The examination of the stifle (knee joint) may need to be conducted under sedation or anesthesia in order to fully evaluate the internal structures. When the cruciate ligament is ruptured or torn most of the stability with the stifle is lost. This instability allows the tibia or shin bone to move forward of the femur or thigh bone. The video shows this instability in a dog with a ruptured cranial cruciate ligament that is under anesthesia. In a normal or uninjured animal this joint typically only moves a very small amount (less than about 5mm excursion), this dog had a complete rupture of the CCL. (Movie1)

The normal or uninjured animal’s stifle or knee joint is picture in Fig.1. (Fig.1 & 2 ) The red line shows the cranial cruciate ligament. This ligament stops the forward movement of the tibia relative to the femur. When this ligament is ruptured as shown in figure 2 the tibia is thrust forward when the animal bears weight on the limb. (Fig. 3 ) This instability is painful and can lead to meniscal tears (if not already present) and eventually to osteoarthritis.

Radiographs or x-rays are taken to ensure there are no other abnormalities and to assess the state of the joint. Most x-rays show symptoms of the torn ligament rather than the actual torn ligament. For example, if present an x-ray can pick-up swelling within the joint (effusion) that is common with injuries of the CCL. X-rays can also detect avulsions (pieces of bone torn off with the ligament) and alignment abnormalities that may be present following rupture of the CCL.

Figure 2

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Once the diagnosis has been established surgery is usually scheduled as soon as possible. Anti-inflammatory and pain medications are usually prescribed prior to surgery at the onset of symptoms. Also once joint disease is documented or even suspected glucosamine supplementation may be warranted. Finally, I find it helpful (if possible) to begin crate training prior to surgery so that post-operative confinement is less stressful for the patient and owner alike.

On the day of surgery the patient arrives at the clinic prior to 9:30am. Instructions for pre-operative home care will be given when surgery is scheduled. Once at the clinic pre-anesthetic blood work is obtained. If the patient is competent to undergo the procedure a pre-anesthetic sedative is administered. An intravenous catheter is then placed and an anesthetic agent is administered. The patient can then be intubated and gas anesthesia is used for the remainder of the procedure. (Fig. 5)

The affected limb is clipped from the hip area to the foot. The skin is prepped with antiseptic solution. The limb is then strapped to an IV fluid stand for a hanging - limb prep. A sterile prep can then be completed around the entire limb. (Fig. 6)

The foot and body are then draped in sterile disposable drapes to maintain a sterile surgical field. The prosthesis or implant used in this surgery is permanent. If the incision site becomes infected it is possible the implant may need to be removed to resolve the problem. Therefore, maintaining a sterile field during surgery is very important. Likewise, antibiotics are given pre-operatively, intra-operatively if required and always for several days after surgery to help prevent infections.

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Once inside the stifle the remnants of the cruciate ligament are excised. This is one of the most important steps of the surgery. If the joint is not properly debrided of loose tissue pain and lameness may persist after surgery. The meniscus must be inspected for tears and damage. If tears are present they too must be debrided in order to have optimum healing after surgery.(Fig. 9,10, & 11 )
Once the joint has been inspected and debrided it is then lavaged. Using a simple 0.9% saline lavage can help remove the enzymes that promote cartilage degradation. Once the joint is as clean as possible the joint capsule is closed. This tissue is commonly imbricated or sutured tightly in order to add as much stability to the joint as possible.

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The plane of dissection is then continued toward the back of the leg to gain exposure to the fabella. The fabella is a small sesamoid bone embedded in a strong ligament at the back of the knee. This is the anchor site for the prosthetic suture. (Fig. 12)

After the suture has been properly anchored two holes are bored through the front and top portion of the tibia or shin bone. The holes are distal or bottom anchor points. Alternatively, some surgeons prefer to drill only one hole and pass the suture through the patellar tendon. I use two holes in an attempt to place the suture in a position that most mimics the natural ligament position. (Fig.13)

Figure12

Once the suture is anchored a crimp device is placed around the suture strands. A tensioning device can then be placed at the suture ends and the suture is placed under tension. The stifle is flexed and extended to ensure adequate range of motion and stability is assessed to ensure proper tension.

The muscle layers are then closed over the suture allowing the muscles to function normally. This also reduces the risk of the suture loosening after surgery and helps prevent seroma formation. (Fig.14 & 15)

Once surgery is complete the real work begins! In this veterinarian’s opinion, post-operative rehabilitation is where CCL surgery becomes a success or failure. Post-operative rehab is as important (maybe more) than which surgical procedure is used to repair the injury. It seems to me that the success of the operation is in direct proportion to the quality and amount of rehab an animal receives. Therefore, the less optimal the rehab the worse the final outcome will be and vice versa. Meticulous adherence to rehab exercises, confinement, medication administration, etc. results in a better outcome. No matter which procedure an animal has to repair the ruptured CCL the outcome or success lies in owner compliance to rehabilitation exercises and care. I can’t stress this point enough – if optimum recovery is expected following CCL surgery it is crucial that one religiously follow their veterinarian’s instructions for after-care.

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[CASE FILE 5] coming soon