Simitri Stable in Stride

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Simitri Stable in Stride is a three part modular surgical implant used during surgery performed on dogs to stabilize the stifle joint (knee) after rupture of the cranial cruciate ligament (CrCL) which is analogous to the anterior cruciate ligament (ACL) in humans.

The canine cranial cruciate ligament performs two main functions: it limits cranial tibial translation (forward movement of the tibia [shin] relative to the femur [thigh]) and internal tibial rotation (inward twisting of the shin relative to the femur). As the CrCL tears, the ability to provide translational and rotational stability is lost. As a result, the knee becomes progressively unstable causing pain, lameness, loss of range of motion and progressive degenerative joint disease (also known as arthritis). [1]

The cause of the CrCL tearing is multifactorial (having many causes) and we don’t yet have a clear picture as to why it occurs. Obesity, conformation, inflammatory conditions of the joint and genetics are all included under the multifactorial umbrella. Genetic factors are undoubtedly important, which would help explain why certain breeds are predisposed, including Labrador and Golden Retrievers, Mastiffs, Rottweilers, Boxers, Staffordshire Terriers, West Highland White Terriers and Newfoundland dogs. [2]

In a Simitri Stable in Stride surgical procedure, unlike tibial-plateau-leveling osteotomy (TPLO) and tibial tuberosity advancement (TTA), no osteotomy (cutting of bone) is required making this a much less invasive procedure. A surgical incision is made on the inside of the affected leg and the Simitri implant is positioned over the center of the stifle (knee) joint. All components of the implant remain under the skin but outside the knee Joint. [3] The architecture of the affected joint is unchanged and the biomechanics are not significantly altered. [4] The implant is fixed in place with six cortical locking screws and once implanted provides immediate and continuous translational and rotational stability throughout the entire range of motion. Dogs are almost always able to weight bear on their surgical leg within 24 hours and are expected to begin a comprehensive rehabilitation program, including controlled leash walks the day they go home.

Lameness scores and stifle range of motion improve improve rapidly and significantly. Most dogs are expected to recover within four months of surgery. [5]

Alternative procedures

Related Research Articles

Knee Region around the kneecap

In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia, and one between the femur and patella. It is the largest joint in the human body. The knee is a modified hinge joint, which permits flexion and extension as well as slight internal and external rotation. The knee is vulnerable to injury and to the development of osteoarthritis.

An osteotomy is a surgical operation whereby a bone is cut to shorten or lengthen it or to change its alignment. It is sometimes performed to correct a hallux valgus, or to straighten a bone that has healed crookedly following a fracture. It is also used to correct a coxa vara, genu valgum, and genu varum. The operation is done under a general anaesthetic.

Posterior cruciate ligament One of four major ligaments of the knee

The posterior cruciate ligament (PCL) is a ligament in each knee of humans and various other animals. It works as a counterpart to the anterior cruciate ligament (ACL). It connects the posterior intercondylar area of the tibia to the medial condyle of the femur. This configuration allows the PCL to resist forces pushing the tibia posteriorly relative to the femur.

Anterior cruciate ligament Type of cruciate ligament in the human knee

The anterior cruciate ligament (ACL) is one of a pair of cruciate ligaments in the human knee. The 2 ligaments are also called cruciform ligaments, as they are arranged in a crossed formation. In the quadruped stifle joint, based on its anatomical position, it is also referred to as the cranial cruciate ligament. The term cruciate translates to cross. This name is fitting because the ACL crosses the posterior cruciate ligament to form an “X”. It is composed of strong fibrous material and assists in controlling excessive motion. This is done by limiting mobility of the joint. The anterior cruciate ligament is one of the four main ligaments of the knee, providing 85% of the restraining force to anterior tibial displacement at 30 degrees and 90 degrees of knee flexion. The ACL is the most injured ligament of the four located in the knee.

Luxating patella

A luxating patella, sometimes called a trick knee, is a condition in which the patella, or kneecap, dislocates or moves out of its normal location.

Knee replacement

Knee replacement, also known as knee arthroplasty, is a surgical procedure to replace the weight-bearing surfaces of the knee joint to relieve pain and disability. It is most commonly performed for osteoarthritis, and also for other knee diseases such as rheumatoid arthritis and psoriatic arthritis. In patients with severe deformity from advanced rheumatoid arthritis, trauma, or long-standing osteoarthritis, the surgery may be more complicated and carry higher risk. Osteoporosis does not typically cause knee pain, deformity, or inflammation and is not a reason to perform knee replacement

Joint replacement

Replacement arthroplasty, or joint replacement surgery, is a procedure of orthopedic surgery in which an arthritic or dysfunctional joint surface is replaced with an orthopedic prosthesis. Joint replacement is considered as a treatment when severe joint pain or dysfunction is not alleviated by less-invasive therapies. It is a form of arthroplasty, and is often indicated from various joint diseases, including osteoarthritis and rheumatoid arthritis.

Medial meniscus

The medial meniscus is a fibrocartilage semicircular band that spans the knee joint medially, located between the medial condyle of the femur and the medial condyle of the tibia. It is also referred to as the internal semilunar fibrocartilage. The medial meniscus has more of a crescent shape while the lateral meniscus is more circular. The anterior aspects of both menisci are connected by the transverse ligament. It is a common site of injury, especially if the knee is twisted.

Stifle joint

The stifle joint is a complex joint in the hind limbs of quadruped mammals such as the sheep, horse or dog. It is the equivalent of the human knee and is often the largest synovial joint in the animal's body. The stifle joint joins three bones: the femur, patella, and tibia. The joint consists of three smaller ones: the femoropatellar joint, medial femorotibial joint, and lateral femorotibial joint.

Cruciate ligament

Cruciate ligaments are pairs of ligaments arranged like a letter X. They occur in several joints of the body, such as the knee joint and the atlanto-axial joint. In a fashion similar to the cords in a toy Jacob's ladder, the crossed ligaments stabilize the joint while allowing a very large range of motion.

Anterior cruciate ligament injury

An anterior cruciate ligament injury occurs when the anterior cruciate ligament (ACL) is either stretched, partially torn, or completely torn. The most common injury is a complete tear. Symptoms include pain, a popping sound during injury, instability of the knee, and joint swelling. Swelling generally appears within a couple of hours. In approximately 50% of cases, other structures of the knee such as surrounding ligaments, cartilage, or meniscus are damaged.

Patellar ligament

The patellar ligament is the distal portion of the common tendon of the quadriceps femoris, which is continued from the patella to the tibial tuberosity. It is also sometimes called the patellar tendon as it is a continuation of the quadriceps tendon.

TPLO, or tibial-plateau-leveling osteotomy, is a surgery performed on dogs to stabilize the stifle joint after ruptures of the cranial cruciate ligament.

Tibial Tuberosity Advancement (TTA) is an orthopedic procedure to repair deficient cranial cruciate ligaments in dogs. It has also been used in cats. This procedure was developed by Dr. Slobodan Tepic and Professor Pierre Montavon at the School of Veterinary Medicine, University of Zurich, in Zurich, Switzerland beginning in the late 1990s.

Unicompartmental knee arthroplasty

Unicompartmental knee arthroplasty (UKA) is a surgical procedure used to relieve arthritis in one of the knee compartments in which the damaged parts of the knee are replaced. UKA surgery may reduce post-operative pain and have a shorter recovery period than a total knee replacement procedure, particularly in people over 75 years of age. Moreover, UKAs may require a smaller incision, less tissue damage, and faster recovery times.

The triple tibial osteotomy is a surgical procedure used to treat dogs that have completely or partially ruptured the cranial cruciate ligament in one or both of their stifles. The cranial cruciate ligament connects the femur with the tibia, which functions to stabilise the canine stifle joint from the forces put on it during exercise and weight bearing.

Tightrope CCL is a veterinary orthopedic surgical method developed to provide a minimally invasive procedure for extracapsular stabilization of the canine cranial cruciate ligament-deficient stifle joint. The cranial cruciate ligament (CrCL) stabilizes the dog knee much like the anterior cruciate ligament (ACL) does in humans.

Posterolateral corner injuries of the knee are injuries to a complex area formed by the interaction of multiple structures. Injuries to the posterolateral corner can be debilitating to the person and require recognition and treatment to avoid long term consequences. Injuries to the PLC often occur in combination with other ligamentous injuries to the knee; most commonly the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). As with any injury, an understanding of the anatomy and functional interactions of the posterolateral corner is important to diagnosing and treating the injury.

Medial knee injuries

Medial knee injuries are the most common type of knee injury. The medial ligament complex of the knee is composed of the superficial medial collateral ligament (sMCL), deep medial collateral ligament (dMCL), and the posterior oblique ligament (POL). These ligaments have also been called the medial collateral ligament (MCL), tibial collateral ligament, mid-third capsular ligament, and oblique fibers of the sMCL, respectively. This complex is the major stabilizer of the medial knee. Injuries to the medial side of the knee are most commonly isolated to these ligaments. A thorough understanding of the anatomy and function of the medial knee structures, along with a detailed history and physical exam, are imperative to diagnosing and treating these injuries.

Posterior cruciate ligament injury

The function of the posterior cruciate ligament (PCL) is to prevent the femur from sliding off the anterior edge of the tibia and to prevent the tibia from displacing posterior to the femur. Common causes of PCL injuries are direct blows to the flexed knee, such as the knee hitting the dashboard in a car accident or falling hard on the knee, both instances displacing the tibia posterior to the femur.


  1. Jerram, RM; Walker, AM (2003). "Cranial cruciate ligament injury in the dog: pathophysiology, diagnosis and treatment". New Zealand Veterinary Journal. 51 (4): 149–158. doi:10.1080/00480169.2003.36357.
  2. Cranial cruciate disease: current status of diagnosis, surgery, and risk of disease. TJ Lampman, EM Lund, AJ Lipowitz. VetComp Ortho Traumatol 3/2003 122-126
  3. Embleton, NA; Barkowski, VJ (2015). "Surgical treatment of canine stifle disruption using a novel extracapsular articulated stifle stabilizing implant". Can. Vet. J. 56: 144–8. PMC   4298264 . PMID   25694662.
  4. Bertocci, GE; Brown, NP; Embleton, NA; Barkowski, VJ. "Biomechanics Associated With a Novel Extracapsular Articulating Implant Predicted Using a Computer Model". Veterinary Surgery. 45: 327–335. doi:10.1111/vsu.12450.
  5. Clinical Evaluation of a Novel Extracapsular Articulating Implant for the Surgical Treatment of Canine Stifle Instability caused by Cranial Cruciate Ligament Disease. NA Embleton, VJ Barkowski. 43rd Annual Veterinary Orthopaedic Society Conference, Big sky, Montana. 2016