Knee
Knee Anatomy
Knee Anatomy
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.
Having a well-functioning healthy knee is essential for our mobility and ability to participate in various activities. Understanding the anatomy of the knee enhances your ability to discuss and choose the right treatment procedure for knee problems with your doctor.
Bones of the Knee
The knee is a hinge joint made up of two bones, the thighbone (femur) and shinbone (tibia). There are two round knobs at the end of the femur called femoral condyles that articulate with the flat surface of the tibia called the tibial plateau. The tibial plateau on the inside of the leg is called the medial tibial plateau and on the outside of the leg, the lateral tibial plateau.
The two femoral condyles form a groove on the front (anterior) side of the knee called the patellofemoral groove. A small bone called the patella sits in this groove and forms the kneecap. It acts as a shield and protects the knee joint from direct trauma.
A fourth bone called the fibula is the other bone of the lower leg. This forms a small joint with the tibia. This joint has very little movement and is not considered a part of the main joint of the knee.
Articular Cartilage and Menisci of the Knee
Movement of the bones causes friction between the articulating surfaces. To reduce this friction, all articulating surfaces involved in the movement are covered with a white, shiny, slippery layer called articular cartilage. The articulating surface of the femoral condyles, tibial plateaus and the back of the patella are covered with this cartilage. The cartilage provides a smooth surface that facilitates easy movement.
To further reduce friction between the articulating surfaces of the bones, the knee joint is lined by a synovial membrane that produces a thick clear fluid called synovial fluid. This fluid lubricates and nourishes the cartilage and bones inside the joint capsule.
Within the knee joint, between the femur and tibia, are two C-shaped cartilaginous structures called menisci. Menisci function to provide stability to the knee by spreading the weight of the upper body across the whole surface of the tibial plateau. The menisci help in load-bearing i.e. it prevents the weight from concentrating onto a small area, which could damage the articular cartilage. The menisci also act as a cushion between the femur and tibia by absorbing the shock produced by activities such as walking, running and jumping.
Ligaments of the Knee
Ligaments are tough bands of tissue that connect one bone to another bone. The ligaments of the knee stabilize the knee joint. There are two important groups of ligaments that hold the bones of the knee joint together, collateral and cruciate ligaments.
Collateral ligaments are present on either side of the knee. They prevent the knee from moving too far during side to side motion. The collateral ligament on the inside is called the medial collateral ligament (MCL) and the collateral ligament on the outside is called the lateral collateral ligament (LCL).
Cruciate ligaments, present inside the knee joint, control the back-and-forth motion of the knee. The cruciate ligament in the front of the knee is called anterior cruciate ligament (ACL) and the cruciate ligament in the back of the knee is called posterior cruciate ligament (PCL).
Muscles of the Knee
There are two major muscles in the knee - the quadriceps and the hamstrings, which enable movement of the knee joint. The quadriceps muscles are located in front of the thigh. When the quadriceps muscles contract, the knee straightens. The hamstrings are located at the back of the thigh. When the hamstring muscles contract, the knee bends.
Tendons of the Knee
A tendon is a tissue that attaches a muscle to a bone. The quadriceps muscles of the knee meet just above the patella and attach to it through a tendon called the quadriceps tendon. The patella further attaches to the tibia through a tendon called the patella tendon. The quadriceps muscle, quadriceps tendon, and patellar tendon all work together to straighten the knee. Similarly, the hamstring muscles at the back of the leg are attached to the knee joint with the hamstring tendon.
Knee Conditions
Chondromalacia Patella
Chondromalacia patella is a common condition characterized by softening, weakening and damage of the cartilage. The condition is most often seen in young athletes and older adults who have arthritis of the knee. It especially occurs in women.
Jumper's Knee
Jumper’s knee, also known as patellar tendinitis, is inflammation of the patellar tendon that connects your kneecap (patella) to your shinbone. This tendon helps in the extension of the lower leg.
Kneecap Bursitis
Bursitis refers to the inflammation and swelling of the bursa. Inflammation of the bursa in front of the kneecap (patella) is known as kneecap bursitis or prepatellar bursitis.
Lateral Patellar Compression Syndrome
Lateral patellar compression syndrome refers to pain under and around your kneecap. It is a common complaint among runners, jumpers and other athletes such as skiers, cyclists, and soccer players.
Shin Splints
Shin splints are pain and inflammation of the tendons, muscles and bone tissue along the tibia or shinbone (lower leg). It occurs because of vigorous physical activities such as exercise or sports. The condition is also referred to as medial tibial stress syndrome (MTSS).
Knee Injury
Pain, swelling, and stiffness are the common symptoms of any damage or injury to the knee. If care is not taken during the initial phases of injury, it may lead to joint damage, which may end up destroying your knee.
Unstable Knee
The knee joint is one of the largest joints in the body. This highly complex joint has several tissues supporting and stabilizing its movement:
Knee Sprain
Knee sprain is a common injury that occurs from overstretching of the ligaments that support the knee joint. A knee sprain occurs when the knee ligaments are twisted or turned beyond its normal range, causing the ligaments to tear.
ACL Tears
The anterior cruciate ligament (ACL) is one of the major ligaments of the knee. It is located in the middle of the knee and runs from the femur (thighbone) to the tibia (shinbone). The ACL prevents the tibia from sliding out in front of the femur. Together with the posterior cruciate ligament (PCL), it provides rotational stability to the knee.
MCL Sprains
The medial collateral ligament (MCL), a band of tissue present on the inside of your knee joint, connects your thighbone and shinbone (bone of your lower leg). The MCL maintains the integrity of the knee joint and prevents it from bending inward.
Meniscal Injuries
Meniscal tears are among the commonest injuries to the knee joint. It can occur at any age but are more common in athletes involved in contact sports. The meniscus has no direct blood supply and for that reason, when there is an injury to the meniscus, healing is difficult.
Meniscal Tears
A meniscal tear is a common knee injury in athletes, especially those involved in contact sports. A sudden bend or twist in your knee causes the meniscus to tear. Elderly people are more prone to degenerative meniscal tears as the cartilage wears out and weakens with age.
Fractures of the Patella
The patella or kneecap is a small bone present in the front of your knee where the thigh bone meets the shinbone. It provides protection to your knee and attachment to muscles in the front of the thigh. An injury to the knee can result in a break or fracture of the patella.
Ligament Injuries
The knee is a hinge joint made up of two bones, the thighbone (femur) and shinbone (tibia). Ligaments are tough bands of tissue that connect one bone to another bone. The ligaments of the knee stabilize the knee joint.
Multiligament Instability
The knee is a complex joint of the body that is vital for movement. The four major ligaments of the knee are anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL) and lateral collateral ligament (LCL).
Knee Arthritis
The joint surface is covered by a smooth articular surface that allows pain-free movement in the joint. Arthritis is a general term covering numerous conditions where the joint surface or cartilage wears out. This surface can wear out for several reasons; often the definite cause is not known. Arthritis often affects the knee joint.
Knee Pain
Knee pain is a common condition affecting individuals of various age groups. It not only affects movement but also impacts your quality of life. An injury or disease of the knee joint or any structure surrounding the knee can result in knee pain. A precise diagnosis of the underlying cause is important to develop an appropriate treatment plan.
PCL Injuries
Posterior cruciate ligament (PCL), one of the four major ligaments of the knee, is situated at the back of the knee. It connects the thighbone (femur) to the shinbone (tibia). The PCL limits the backward motion of the shinbone.
Patellar Instability
Any damage to the supporting ligaments may cause the patella to slip out of the groove either partially (subluxation) or completely (dislocation). This misalignment can damage the underlying soft structures such as muscles and ligaments that hold the kneecap in place.
Patellofemoral Instability
Patellofemoral instability means that the patella (kneecap) moves out of its normal pattern of alignment. This malalignment can damage the underlying soft structures such as muscles and ligaments that hold the knee in place.
Patella Fracture
The kneecap or patella forms a part of the knee joint. It is present at the front of the knee, protecting the knee and providing attachment to various muscle groups of the thigh and leg. The undersurface of the kneecap and the lower end of the femur are coated with articular cartilage, which helps in smooth movement of the knee joint.
Patellar Tendon Rupture
The patellar tendon works together with the quadriceps muscle and the quadriceps tendon to allow your knee to straighten out. Patella tendon rupture is the rupture of the tendon that connects the patella (kneecap) to the top portion of the tibia (shinbone).
Posterolateral Instability
Posterolateral instability, also known as posterolateral rotatory instability (PLRI), is a common pattern of knee instability that results from injuries to the structures that support the outside of the knee joint, the posterolateral corner. When individuals injure the knee ligaments, they are most likely to injure the structures of the posterolateral corner.
Medial Gastrocnemius Strain
A medial gastrocnemius strain (MGS), also sometimes called “tennis leg”, is an injury to the calf muscle in the back of the leg. It occurs when the calf muscle is stretched too far resulting in a partial or total tear or rupture within the muscle.
Articular Cartilage Injury
Articular or hyaline cartilage is the tissue lining the surface of the two bones in the knee joint. Cartilage helps the bones move smoothly against each other and can withstand the weight of the body during activities such as running and jumping. Articular cartilage does not have a direct blood supply to it so has little capacity to repair itself.
Knee Fracture
A fracture is a condition in which there is a break in the continuity of the bone. In younger individuals, these fractures are caused by high energy injuries, as from a motor vehicle accident. In older people, the most common cause is a weak and fragile bone.
Knee Osteoarthritis
Osteoarthritis also called degenerative joint disease, is the most common form of arthritis. It occurs most often in older people. This disease affects the tissue covering the ends of bones in a joint (cartilage).In a person with osteoarthritis, the cartilage becomes damaged and worn out causing pain, swelling, stiffness and restricted movement in the affected joint.
Knee Sports Injuries
Trauma is any injury caused during physical activity, motor vehicle accidents, electric shock, or other activities. Sports trauma or sports injuries refer to injuries caused while playing indoor or outdoor sports and exercising. Sports trauma can result from accidents, inadequate training, improper use of protective devices, or insufficient stretching or warm-up exercises. The most common sports injuries are sprains and strains, fractures, and dislocations.
Patellar Tendinitis
Patellar tendinitis, also known as "jumper's knee", is an inflammation of the patellar tendon that connects your kneecap (patella) to your shinbone. This tendon helps in extension of the lower leg.
Medial Meniscus Syndrome
Of the menisci within the knee, it is the medial that is more easily injured. Differences in the anatomical attachments of the medial meniscus compared to the lateral, mean that the medial meniscus becomes distorted during combined flexion and rotation movements in a manner not experienced on the lateral side.
Multiligament Knee Injuries
Injury to more than one knee ligament is called a multiligament knee injury and may occur during sports or other physical activities.
Anterior Knee Pain
Anterior knee pain is characterized by chronic pain over the front and center of the knee joint. It is common in athletes, active adolescents (especially girls) and overweight individuals. Anterior knee pain refers to various conditions, which include runner's knee or patellar tendinitis, and chondromalacia of the patella.
Runner's Knee
Patellofemoral pain syndrome also called runner’s knee refers to pain under and around your kneecap. Patellofemoral pain is associated with a number of medical conditions such as anterior knee pain syndrome, patellofemoral malalignment, and chondromalacia patella.
Knee Procedures
Knee Arthroscopy
Knee arthroscopy is a common surgical procedure performed using an arthroscope, a viewing instrument, to diagnose or treat a knee problem. It is a relatively safe procedure and you will usually be discharged from the hospital on the same day of surgery.
Meniscal Surgery
Meniscal surgery is a surgical procedure employed for the treatment of torn or damaged meniscal tissues in the knee. It is mostly performed as a minimally invasive keyhole procedure.
ACL Reconstruction
ACL (anterior cruciate ligament) reconstruction is a commonly performed surgical procedure. With recent advances in arthroscopic surgery, it can now be performed with minimal incision and low complication rates.
Meniscal Transplantation
The meniscus is a C-shaped cartilage ring that acts as a cushion between the shinbone and the thighbone. Each of your knees has two menisci - one on the inside (medial aspect) and the other on the outside (lateral aspect)of your knee. Apart from the cushioning effect, the menisci also provide stability to the knee.
Medial Patellofemoral Ligament Reconstruction
The medial patellofemoral ligament is a band of tissue that extends from the femoral medial epicondyle to the superior aspect of the patella. It is a major ligament that stabilizes the patella and helps in preventing patellar subluxation (partial dislocation) or dislocation.
Knee Cartilage Restoration
Knee cartilage restoration is a surgical technique to repair damaged articular cartilage in the knee joint by stimulating new growth of cartilage or by transplanting cartilage into areas with defects in order to relieve pain and restore normal function to the knee.
Cartilage Repair and Transplantation
The articular surfaces of the body’s joints are lined by hyaline cartilage, a smooth tissue that serves as a shock absorber and allows easy movement of the bones within the joint. Normal wear-and-tear or injury can damage and cause defects in the cartilage, resulting in irregular articular surfaces that interfere with movement, causing pain, swelling and disability.
Matrix Induced Autologous Chondrocyte Implantation (MACI)
Matrix-Induced autologous chondrocyte implantation is an innovative, FDA-approved cartilage restoration procedure that uses your own cells to repair cartilage defects in your knee. It can alleviate knee pain, help you regain function and may even delay or prevent arthritis.
Multiligament Reconstruction of the Knee
Multiligament knee reconstruction is a surgical procedure to repair or replace two or more damaged ligaments of the knee joint. The surgery can be performed using minimally invasive techniques.
Cartilage Replacement
Articular or hyaline cartilage is the tissue that covers bone surface of the knee which helps in smooth interaction between the two bones in the knee joint. It has less capacity to repair by itself because there is no direct blood supply to cartilage.
Cartilage Microfracture
Cartilage microfracture is a surgical procedure performed to replace the worn-out articular cartilage with new cartilage.
Intraarticluar Knee Injection
Knee pain and stiffness can be disabling and difficult to treat. It can limit an individual’s lifestyle and negatively impact body image and emotional well-being.
Knee Fracture Surgery
A knee fracture is a broken bone or a crack in or around the joint of the knee. This can involve the tibia (shin bone), the kneecap (patella), or femur (thighbone) where they connect with the knee.
Arthroscopic Debridement
Arthroscopic debridement is a minimally invasive surgical procedure to treat osteoarthritis caused by an injury or damage to the articular cartilage of the knee joint resulting in restricted motion of the knee. Dr. Mehta provides diagnosis and arthroscopic debridement surgery in Geneva, IL.
LPFL Reconstruction
LPFL reconstruction or lateral patellofemoral ligament reconstruction is a surgical procedure employed to treat patients with severe patellofemoral instability. The procedure involves replacing a torn lateral patellofemoral ligament with a part of a tendon taken from your leg. The main objective of the LPFL reconstruction is to tighten the knee joint and restore its stability.
Mosaicplasty
Weight-bearing joints, such as the knee, may develop defects in the articular cartilage (spongy tissue that lines and cushions joints during movement) due to stress, trauma or degenerative disease. This can lead to pain, swelling or locking at the joint. Mosaicplasty is a surgical technique to repair the defect by transplanting healthy bone and cartilage from non-weight bearing areas of the knee.
Partial Knee Resurfacing
Partial knee replacement is an alternative to total knee replacement in patients with arthritis on only one side of the knee. Partial knee replacement is a surgical procedure which involves resurfacing and replacement of only the diseased surface of the joint instead of the entire joint.
Hamstring Allograft
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. When this ligament tears, it does not heal on its own and often leads to the feeling of instability in the knee.
Viscosupplementation
Viscosupplementation refers to the injection of a hyaluronan preparation into the joint. Hyaluronan is a natural substance present in the joint fluid that assists in lubrication. It allows the smooth movement of the cartilage-covered articulating surfaces of the joint.
Patellar Tendon Repair
Patellar tendon repair is the surgery performed to reattach the torn tendon to the kneecap and to restore normal function in the affected leg.
PCL Reconstruction
PCL reconstruction surgery is a procedure to correct torn posterior cruciate ligament (PCL) in the knee using a tissue graft taken from another part of the body, or from a donor.
LCL Reconstruction
LCL reconstruction is a surgical procedure to repair torn or damaged lateral collateral ligament in the knee using a tissue graft taken from another part of the body, or from a donor.
ACL Reconstruction with Patellar Tendon
Anterior cruciate ligament (ACL) reconstruction with patellar tendon is a surgical procedure that replaces the injured ACL with a patellar tendon. The goal of ACL reconstruction surgery is to tighten your knee and to restore its stability.
ACL Reconstruction Procedure with Hamstring Tendon
Anterior cruciate ligament (ACL) reconstruction with hamstring tendon is a surgical procedure to replace the torn ACL with part of the hamstring tendon taken from your leg. The hamstring is the muscle located on the back of your thigh. The goal of ACL reconstruction surgery is to tighten your knee and restore its stability.
MCL Reconstruction
MCL reconstruction is a minimally invasive surgical procedure in which a tendon graft is utilized to reconstruct the injured MCL.
Partial Meniscectomy
Partial meniscectomy is a surgical procedure to remove the torn portion of the meniscus from the knee joint.
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