Bridge Enhanced ACL Restoration (BEAR)
Bridge Enhanced ACL Restoration (BEAR) refers to a novel FDA-approved surgical technique used to treat a torn anterior cruciate ligament (ACL).
In traditional ACL surgery, your surgeon restores or reconstructs the torn ACL utilizing a tissue graft (piece of tendon) taken from another area of your body (autograft) or a donor (allograft) to replace the torn ACL.
Instead of reconstructing the ACL utilizing a graft, the BEAR technique involves utilizing a medical device called a BEAR Implant to bridge the gap between the torn ACL ends. The BEAR Implant is a resorbable implant (meaning it gets absorbed by the body) that is made from purified bovine (cow) collagen and is secured via sutures to bridge the gap between the torn ends of a patient’s ACL. The patient’s own blood is injected into the implant during the surgical implantation procedure with the aim of forming a device-protected clot that stimulates the body’s healing process. Within about 8 weeks of the BEAR implant procedure, the implant is absorbed and replaced by the body’s own tissue. An advantage of utilizing the BEAR Implant is that your surgeon does not need to obtain any graft tissue from another section of your body.
Anatomy of the ACL
The anterior cruciate ligament is one of the four major ligaments of the knee that connects the femur (thighbone) to the tibia (shinbone) and helps stabilize your knee joint. It prevents excessive forward movement of the tibia in relation to the femur as well as limiting rotational movement of the knee. When this ligament tears, unfortunately it does not heal on its own and often leads to the feeling of instability in the knee, requiring reconstruction to correct the abnormality.
ACL reconstruction surgery with a Bridge Enhanced ACL Restoration (BEAR) technique is indicated for skeletally mature patients of at least 14 years of age with a complete ACL tear, as confirmed by MRI. Patients should have an ACL stump connected to the tibia to enable restoration of the ACL and the implantation should be done within 50 days of the original ACL injury. The BEAR technique has been found to be effective across a wide range of tear types (type 1 through 4). ACL tears most often occur during sports activities that involve pivoting, cutting, and turning movements as in football, soccer, skiing, tennis, and basketball.
Preparation for the Bridge Enhanced ACL Restoration (BEAR) technique may involve the following steps:
- A thorough history and physical examination
- Routine blood work and imaging
- Informing your doctor of any medications or supplements you are taking or any conditions you have such as heart or lung disease
- Informing your doctor of any allergies to medications, anesthesia, or latex
- Refraining from medications such as blood thinners, aspirin, or NSAIDs or adjusting the doses, if indicated
- Refraining from solids or liquids at least 8 hours prior to the procedure
- Arranging for someone to drive you home after the procedure
ACL reconstruction surgery with a Bridge Enhanced ACL Restoration (BEAR) technique is usually performed arthroscopically under general anesthesia. In general, the procedure involves the following steps:
- Your surgeon will make two to three small cuts, about 1/4-inch-long, around your knee.
- An arthroscope is inserted into the knee joint through one of the incisions.
- An arthroscope is a thin tubular instrument with a camera, light, and a magnifying lens attached at the end that is connected to an external monitor and enables your surgeon to view the inside of the knee joint.
- Along with the arthroscope, a sterile solution is pumped into the joint to expand it, enabling your surgeon to have a clear view and space to work inside the joint.
- Miniature surgical instruments are passed through the other incisions and the BEAR implant is placed in the space between the torn ACL ends. The BEAR implant serves as a bridge to help the ends of the torn ACL heal together while maintaining the ACL's original attachments to the knee joints.
- The patient’s own blood is then added to the BEAR implant to activate clot formation. This eventually acts as a bridging structure that supports cellular migration and proliferation.
- Finally, the BEAR implant is secured by stitching the torn ACL ends onto it. Within 8 weeks of implantation, the BEAR implant device will be absorbed by the body and replaced by new native cells and tissues that will later become the new ligament.
- The scope and the instruments are withdrawn, and the incisions are closed with sutures or Steri-Strips (tape) and covered with a sterile dressing.
In general, postoperative care instructions and recovery after a Bridge Enhanced ACL Restoration (BEAR) will involve the following:
- You may notice pain, swelling, and discomfort in the knee area. Pain and anti-inflammatory medications are provided as needed to keep you comfortable.
- You will be given assistive devices such as braces and crutches with instructions on restricted weight-bearing for a specified period.
- You are encouraged to walk with assistance as frequently as possible to prevent blood clots.
- Instructions on surgical site care and bathing will be provided to keep the wound clean and dry.
- Refrain from strenuous activities and lifting heavy weights for a specified period. A gradual increase in activities is recommended.
- An individualized physical therapy protocol will be designed to help strengthen the knee muscles and optimize knee function.
The benefits of the Bridge Enhanced ACL Restoration (BEAR) technique over the traditional ACL reconstruction technique include:
- No need for graft tissue for reconstruction
- Prevents potential autograft/allograft tissue complications
- Less likelihood of post-traumatic osteoarthritis
- Higher level knee function scores
- Early return to sports activities
- Restores native ACL and function
- Minimally invasive/easy revision surgery
- Better overall functional outcome
Risks and Complications
The Bridge Enhanced ACL Restoration (BEAR) surgery is a relatively safe procedure; however, as with any surgery, some risks and complications may occur, such as the following:
- Knee pain
- Allergic/anesthetic reactions
- Re-tear or reinjury
- Blood clot or deep vein thrombosis (DVT)
- Damage to adjacent soft tissue structures
- Stiffness or limited range of motion
The Bridge Enhanced ACL Restoration (BEAR) technique is a less invasive way to treat ACL tears. It stimulates healing of the native ligament with stitches and an implant. The implant is a bio-engineered sponge saturated with the patient’s own blood to promote clotting and create an environment in which torn ACL tissues can grow back together.