What is Knee Surgery?
Knee surgery is a surgical procedure for the treatment of a knee injury or condition. The procedure involves repairing diseased or damaged structures of the knee joint in order to eliminate pain and restore normal function.
The knee is a complex joint made up of different structures - bones, tendons, ligaments, and muscles. They all work together to maintain the knee’s normal function and provide stability to the knee during movement. Any damage to these structures may warrant a knee surgery.
Anatomy of the Knee
The knee is one of the largest joints in the body, formed by the lower end of the femur (thigh bone), the upper end of the tibia (shinbone), and the patella (kneecap). Several ligaments and muscles attach to the bones of the knee joint to maintain the normal motion of the joint. Special tissues known as menisci are located between the two articular ends of the joint. These act as a cushion between the articular surfaces and absorb shock during movement.
Indications for Knee Surgery
Knee surgery is indicated when non-surgical treatments such as medications, injections, and physical therapy have been unsuccessful in treating knee conditions such as:
- Moderate to severe arthritis
- Torn or damaged cruciate ligaments
- Torn or damaged menisci
- Torn or damaged articular cartilage
- Patellar tracking (a kneecap that is misaligned)
- Fracture of the knee bones
- Inflamed synovium (the soft tissue that lines the joint)
- Baker’s cyst: A fluid-filled cyst that develops at the back of the knee due to the accumulation of synovial fluid.
Preparation for Knee Surgery
Preoperative preparation for knee surgery generally involves the following steps:
- A thorough examination is performed by your doctor to check for any medical issues that need to be addressed prior to surgery.
- Depending on your medical history, social history, and age, you may need to undergo tests such as blood work and imaging to screen for any abnormalities that could compromise the safety of the procedure.
- You will be asked if you have allergies to medications, anesthesia, or latex.
- You should inform your doctor of any medications, vitamins, or supplements that you are taking.
- You may need to stop taking supplements or medications such as blood-thinners or anti-inflammatories for a week or two prior to surgery.
- You should refrain from alcohol or tobacco at least a week before surgery.
- You should not consume solids or liquids at least 8 hours prior to surgery.
- Arrange for someone to drive you home after surgery.
- A written consent will be obtained from you after the surgical procedure has been explained in detail.
Procedure for Knee Surgery
Several types of knee surgery can be performed based on your knee condition. Knee surgery is usually performed under general or local anesthesia, either as an open surgery or as a minimally invasive arthroscopic procedure.
In an arthroscopic procedure, tiny incisions (portals), about a half-inch in length, are made around the knee joint. Through one of the incisions, an arthroscope - a small flexible tube with a light and video camera at the end - is passed into the joint. The camera attached to the arthroscope displays the images of the inside of the joint on a monitor, which allows your surgeon to view the damage and carry out the required repair.
In an open surgery, a long incision of several centimeters is made over the knee joint. The underlying soft tissues are carefully moved aside to expose the treatment area. Special surgical tools are used to carry out the required repair around the joint. Once the repair is complete, the instruments are removed, and the incisions are closed with stitches or small sterile bandage strips.
Some of the common knee surgeries include:
- Surgery for Meniscal Tears: Knee arthroscopy is the commonly recommended surgical procedure for meniscal tears. The surgical treatment options include:
- Meniscus removal (meniscectomy): During a meniscectomy, small instruments called shavers or scissors may be used to remove the torn meniscus.
- Meniscus repair: In arthroscopic meniscus repair, the torn meniscus will be pinned or sutured depending on the extent of the tear.
- Meniscus replacement: Meniscus replacement or transplantation involves the replacement of torn cartilage with the cartilage obtained from a donor, or a cultured patch obtained from the laboratory.
- Surgery for patellofemoral instability/patellar tracking: Patellofemoral realignment is surgery employed for patellofemoral stabilization to treat symptomatic patellofemoral instability. The aim of the surgery is to realign the kneecap in the groove and to decrease the Q angle. After visualizing the type and severity of the injury, your surgeon decides on one of the following surgical corrections:
- A lateral retinacular release may be performed, where your surgeon releases or cuts the tight ligaments on the lateral side (outside) of the patella, enabling it to slide more easily in the femoral groove. Your surgeon may also perform a procedure to realign the quadriceps mechanism by tightening the tendons on the inside or medial side of the knee.
- If the misalignment is severe, tibial tubercle transfer (TTT) will be performed. This procedure involves the removal of a section of bone where the patellar tendon attaches to the tibia. The bony section is then shifted and properly realigned with the patella and reattached to the tibia with two screws.
- Medial patellofemoral ligament (MPFL) reconstruction with graft is another surgery employed for severe patellofemoral instability. This procedure involves fixing a brand new ligament from the medial aspect of the thighbone into the medial aspect of the kneecap. This enhances the medial pull on the kneecap in the earliest phases of knee flexion and guides the kneecap successfully into the trochlear groove.
- Patellar/quadriceps tendon repair surgery involves reattaching the torn patellar/quadriceps tendon to the kneecap to restore normal knee function. The quadriceps tendon is located at the top of the patella, whereas the patellar tendon is located below it. An incision is made on the front of the knee to expose the tendon rupture. Holes are made in the patella, and strong sutures are tied to the tendon and threaded through these holes. These sutures pull the torn edge of the tendon back to its normal position on the kneecap.
- ACL Reconstruction: The anterior cruciate ligament (ACL) is one of the major stabilizing ligaments in the knee. It is a strong, rope-like structure located in the center of the knee, running from the femur to the tibia. The ACL prevents the tibia from sliding out in front of the femur. The usual surgery for an ACL tear is an ACL reconstruction, which tightens your knee and restores its stability. Surgery to reconstruct an ACL is performed with an arthroscope, using small incisions. During the surgery, your doctor will replace the torn ligament with a tissue graft that can be obtained from your knee (patellar tendon) or hamstring muscle.
- Cartilage replacement/restoration: Articular or hyaline cartilage is the tissue that covers the bone surfaces within the knee, aiding in smooth interaction between the two bones in the knee joint. Cartilage replacement is a surgical procedure performed to replace the worn-out cartilage with new cartilage. Cartilage replacement helps relieve pain, restore normal function, and can delay or prevent the onset of arthritis. The goal of the cartilage replacement procedure is to stimulate the growth of new hyaline cartilage. Various arthroscopic procedures involved in cartilage replacement include:
- Microfracture: Microfracture involves creating numerous tiny holes in the injured joint surface using a special tool called an awl. The holes are made in the bone under the cartilage, called the subchondral bone. This creates a new blood supply to the cartilage, which stimulates growth.
- Drilling: This procedure is similar to a microfracture, whereby multiple holes are created in the injured joint area using a surgical drill or wires.
- Abrasion arthroplasty: This procedure is similar to drilling, but involves the use of high-speed burs to remove the damaged cartilage.
- Autologous chondrocyte implantation (ACI): This is a two-step procedure in which the healthy cartilage cells are removed from a non-weight-bearing joint, grown in the laboratory, and then implanted into the cartilage defect. During this procedure, a patch is harvested from the periosteum, a layer of thick tissue that covers the bone and sewn over the defective area using fibrin glue. The new cartilage cells are then injected under the periosteum into the cartilage defect to allow the growth of new cartilage cells.
- Osteochondral autograft transplantation: In this procedure, plugs of cartilage are removed from the non-weight-bearing areas of your knee and transferred to the damaged areas of the joint. This method is used to treat smaller cartilage defects since the graft that is taken from your own body will be limited.
- Osteochondral allograft transplantation: In this procedure, healthy cartilage tissue is taken from a donor from the bone bank. This is used as a graft and transplanted to the area of cartilage defect.
- Knee replacement surgery: This is a surgery commonly employed for the treatment of knee joint arthritis or damage to the knee joint as a result of severe trauma or fracture. In this surgery, the damaged articulating parts of the knee joint are removed and replaced with artificial prostheses to restore normal knee function.
- Knee osteotomy: Knee osteotomy is a surgical procedure in which the upper shinbone (tibia) or lower thighbone (femur) is cut and realigned. It is usually performed in arthritic conditions affecting only one side of your knee. The aim is to take pressure off the damaged area and shift it to the other side of your knee with healthy cartilage. During the surgery, your surgeon will remove or add a wedge of bone either below or above the knee joint, depending on the site of arthritic damage.
Postoperative Care and Recovery
In general, postoperative care instructions and recovery after knee surgery will involve the following steps:
- You will be transferred to the recovery area where your nurse will closely observe you for any allergic/anesthetic reactions and monitor your vital signs as you recover.
- You may notice some pain, swelling, and discomfort in the knee area. Pain and anti-inflammatory medications are provided as needed.
- Antibiotics are also prescribed as needed to address the risk of surgery-related infection.
- Keep the surgical site clean and dry. Instructions on surgical site care and bathing will be provided.
- You will be placed on crutches for the first few weeks with instructions on restricted weight-bearing. You are encouraged to walk with assistance as frequently as possible to prevent blood clots.
- You are advised to keep your leg elevated while resting to prevent swelling and pain.
- Refrain from smoking as it can negatively affect the healing process.
- Eating a healthy diet rich in vitamin D is strongly advised to promote healing and a faster recovery.
- Refrain from strenuous activities and lifting heavy weights for the first couple of months. Gradual increase in activities over a period of time is recommended.
- An individualized physical therapy protocol is designed to help strengthen your knee muscles and optimize knee function.
- You will be able to resume your normal activities in a month or two after surgery; however, you may have certain activity restrictions, and return to sports may take at least 6 months or longer.
- Refrain from driving until you are fully fit and receive your doctor’s consent.
- A periodic follow-up appointment will be scheduled to monitor your progress.
Risks and Complications
Knee surgery is a relatively safe procedure; however, as with any surgery, some risks and complications may occur, such as:
- Blood clots or deep vein thrombosis (DVT)
- Anesthetic/allergic reactions
- Injury to adjacent soft-tissue structures
- Continued stiffness or pain
- Failure of the prosthesis
- Failure of the graft
- Need for additional surgery