MMP Cruciate Surgery

Dr. Sam Joyce has been performing MMP's in Bend, Oregon for over 5 years, and has achieved very positive results for his patients, including his own dog, Voyager One.

Orthopedic Surgery Available for Pets

One of the most common orthopedic conditions in dogs is a rupture of the cranial cruciate ligament. This ligament attaches the femur to the tibia inside the knee joint and acts as a stabilizing structure that prevents abnormal movement in the joint while allowing full range of motion. When the cruciate ligament is compromised by a partial or complete tear, the joint becomes unstable resulting in inflammation, swelling and pain. This instability can compromise the meniscus resulting in fraying or tearing of this intra-articular "cushion".

Our first step is to evaluate the patient for pain and joint instability during the course of an office visit and to subsequently take appropriate radiographs under sedation. These radiographs are useful for diagnostic and surgical planning purposes. We also take this opportunity to further evaluate the joint for instability while the patient is relaxed.


Pre-operative care helps our veterinarian make the surgery go as smoothly as possible. The first step involves discussing your pet's treatment options. Some conditions, such as a ruptured ACL or hip dysplasia, respond to any of several types of surgical correction or restoration. Your veterinarian will discuss these options with you so you can make an informed choice. If your pet's orthopedic problem has been previously evaluated and diagnosed by another veterinarian, it is helpful for you to obtain the X-rays and other documentation from that visit. Of course, we are also able to provide a full evaluation as needed.


Pet owners generally do not have to make elaborate preparations for the day of the procedure. The night before, withhold all food after your pet's final meal of the day. Our veterinarian asks owners to do this because general anesthesia can sometimes increase the risk of vomiting. There's no need to withhold water, however. On the morning of the surgery, go ahead and take your pet for their usual walk, but try to restrict them from running around or other vigorous exercise. We recommend that you allow plenty of time for the surgery so you can arrive early. Your pet will feel more relaxed if you are feeling calm and relaxed as well!


Post-operative care involves helping your pet remain comfortable and making sure that the wound heals properly. The full healing time for orthopedic surgery may take months, during which time the animal can re-injure by overtaxing the repaired bones or joints. A carrier or pet crate is recommended to keep your pet's activities at a minimum while they recover. We can advise you on the right size and type of carrier for your pet. Even if your pet is capable of walking on the newly-repaired limb, prevent him from climbing stairs until your veterinarian has cleared them for this activity.

Cranial Cruciate Ligament Injury

Diagnosing a Torn CrCL

Dogs with CrCL rupture often have a history of a mild rear limb lameness some months in the past, which may have resolved (a partial tear or an initial CrCL insult). They present with a persistent, often severe lameness in a rear limb.

On physical examination:

  • Pain in the stifle joint when tested by your veterinarian
  • Positive “sit test” - that is, when the dog is asked to “Sit”, they are unable to do so squarely with the stifles fully flexed under the pelvis. The painful leg has joint swelling, so the dog sticks the leg out in a “crooked sit”.
  • Increased joint fluid pressure in the stifle, which makes the patellar tendon less easy to palpate physically. This may only be appreciated on radiographs.
  • Thickening of the inside of the stifle joint - called “medial buttressing.”


  • Signs of arthritic changes in the bones of the stifle.
  • Evidence of joint fluid swelling
  • Absence of any fractures or bone cancer

Treatment Options

Veterinarians may have several options for your pet, but all of them must take into consideration several things: the age of your pet, the general activity of your pet (for example is it a house pet, or an agility champion working dog), your ability as an owner to perform the needed recovery care at home after the surgery, and also your finances, as the options can have very different costs.

House rest

House Rest and medications for inflammation and pain. This option is most viable in the cat (one who is not too overweight), and in very small dogs. Some dogs seem to manage pretty well with minimal lameness, so this option may be appropriate. It is obviously less expensive, but most individuals will never return to normal function. Research shows that most dogs will have continued long-term lameness when no surgery is performed and get more degenerative arthritis. Research is clear that performing ANY surgery is likely better than no surgery at all except as noted above.

Tightening Procedures

Extracapsular Surgical Repair (ECR)

Sometimes called Lateral Fabello-Tibial suture, it is a “tightening” procedure for the stifle. This option may be available to your dog with your general practice veterinarian, depending on their experience with orthopedic surgery. Veterinarians have performed this surgery for decades, and it is still performed even in many universities, and has a long track record of improving lameness even in larger dogs. While degenerative arthritic changes are inevitable with this ligament injury, dogs that have this surgery are likely to be at least 75 to 80% of normal, and most owners are satisfied that the procedure helps a pet dog to perform normal activities and be relatively comfortable in the long-term. This procedure usually involves the use of heavy nylon sutures outside the joint to mimic the function of the CrCL, stabilizing the stifle joint, and minimizing pain with weight bearing. ECR dogs are slow to bear weight after surgery - 1 to 3 weeks, and ECR relies on the body to scar down or thicken the joint capsule of the stifle over time to provide stability. The suture may break over time, but scar tissue should hold the stifle in an appropriate position for good function after 6 to 8 weeks. This means a return to normal activity over about 8 weeks.

Other “Tightening” Procedures

Procedures such as Fascial Graft Techniques are generally done by older surgeons, and are less common today. Tightrope Procedure is a tightening procedure with a proprietary material which has experienced high rates of surgical infections, and failures, so this clinic does not perform this procedure.

Bone-Cutting Procedures

Tibial Plateau Leveling Osteotomy (TPLO).

Patented by a veterinary surgeon and engineer in Eugene, Oregon, this procedure has become the procedure of choice, at least in the USA. Performed almost exclusively by board certified veterinary surgeons, this surgical repair for CrCL injury is much more expensive, much more technically difficult, but may also be a better approach to repair for large dogs, or those dogs that aim to go back to some level of athletic performance. The procedure involves calculating the angle of the tibial plateau, and cutting the tibia bone and rotating the top of the tibia to correct the instability during weight-bearing, to minimize the excessive forces on the stifle, minimizing pull on the joint capsule, and to attempt to minimize degenerative arthritis in the joint. Controlled studies are now available. There certainly seems to be less arthritis over time, and return to better performance compared to Tightening Procedures. Neither procedure gets the dog back to pre-injury performance, and few individuals are normal again, however, TPLO does seem to get a better consistency of long-term result. As with other bone-cutting procedures, dogs are walking on the leg very quickly after surgery. Because it involves bone cutting of the shaft of the tibia bone, and a thick bone plate on the leg, and time needed to heal the bone, the recovery from surgery is longer than in Tightening procedures, and client compliance on home care is vital. Return to normal activity can be as long as 3 to 4 months waiting for bone healing. While small and medium dogs might benefit from this procedure, it is large and very large dogs that seem to derive the most benefit from this procedure.

Tibial Tuberosity Advancement (TTA)

This procedure was introduced in Europe, and has been performed by some surgeons in the United States over the last 10-20 years. It is also a technically challenging bone-cutting procedure that changes the angle of the stifle joint, with a similar mechanical end-point as the TPLO. Moving, or “Advancing” the tibial tuberosity changes the patellar tendon angle and neutralizes the forces on the joint. TTA now has multiple studies that show nearly as good results as with TPLO. It is intermediate in cost, below that of the TPLO, because it does not require referral to a specialty hospital. For large dogs it is a viable procedure for quick return to weight-bearing and good consistency of result, yet unlike the TPLO, leaves the tibial bone shaft intact for weight bearing after surgery. This procedure has had some increased problems with meniscal lameness months after surgery, averaging 10% late meniscal tears causing lameness, but is a stout, strong fixation for very large dogs. Like the TPLO, it is quite invasive, and will take a couple of months to recover from the surgery trauma. Dogs with TTA are generally healed in 8 weeks, still less time than the TPLO for return to normal activity.

Modified Maquet Procedure (MMP)

This is a modification of the TTA procedure, which has about 30,000 clinical cases in Europe since 2010. We have been performing this procedure for over five years due to lower cost, less invasive tissue trauma, shorter surgery time, and good clinical outcomes. Like the other bone-cutting procedures, large dogs will be quick to weight-bear post-operatively, but we find much less pain due to a smaller incision, and less tissue trauma. This procedure, while still technically challenging, takes the surgeon much less time to perform. Like the TTA, a tibial tuberosity advancement is made, but the use of a patented titanium foam wedge that is more biologically compatible with the bone leads to much quicker healing times, so faster return to function, and a similar 8 week recovery to normal activity as TTA. Late meniscal lameness is reduced to comparable to TPLO, and less than traditional TTA’s. But dogs are much less painful than with either of the other bone cutting procedures. Four weeks of very careful walking activity and NO loose activity or running is required, but after 4 weeks, return to brisk walks is allowed, and beginning to start full function activities by 8 weeks. Studies have shown 91% of dogs return to “Full Function” which is comparable to both TTA and TPLO in a less expensive procedure.

ProcedureProsConsCost (Approx) 
No Surgery
  • No anesthetic risks
  • Some small dogs and cats can manage pretty well
  • Least cost
  • May do better with rehab and acupuncture
  • Long-term pain medicine may be needed and costly
  • Long-term lameness likely
  • More arthritic, poorer function
  • Pain meds
  • Other modalities
Extracapsular Repair (ECR)
  • Least expensive surgery
  • Slow to weight bear after surgery
  • Fastest return to regular activity at 6-8 weeks
  • No bone healing needed
  • Generally, clients are satisfied about the pet’s outcome
  • Variable results
  • Some larger dogs don’t do as well
  • Arthritis is inevitable, and worse than bone-cutting techniques
  • Expect an occ. limp
$2000 - $2500
  • Literature rated as #1
  • Best for giant dogs or those with abnormal tibial angles
  • Very strong
  • Stats: lowest arthritis, best long term athletic performance
  • Weight bearing in 1 to 2 days
  • Very expensive
  • Requires referral to specialty hospital
  • 4 months average return to normal activity
  • Invasive
  • Rarely fail, but if so, can be catastrophic

$6000 - $8000

  • Less technically difficult to perform than TPLO
  • Very strong for giant dogs
  • Nearly similar results to TPLO
  • Weight bearing in 1 to 2 days
  • Failures rarely need surgery
  • Large incision, invasive
  • More painful than MMP
  • Still costly, but done without referral
  • 10% meniscal lameness

$3000 - $3800

  • Least expensive of the bone cutting procedures
  • Faster surgery than TTA
  • No referral needed
  • Weight bearing in 1 to 2 days
  • Less pain and discomfort post-op
  • Return to normal function in 8 weeks
  • Bone healing in 4 to 5 weeks
  • Late meniscal lameness comparable to TPLO
  • <1% tibial fractures with off leash activity <21 days
  • 4 weeks to allow leash walks
$2500 - $3400