Knee

  • Anatomy
  • Conditions
  • Procedures

Knee Anatomy

The knee is a complex joint made up of different structures including bones, tendons, ligaments and muscles. They all work together to maintain 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 the shinbone (tibia). There are two round knobs at the end of the femur called femoral condyles which articulate with the flat surface of the tibia called the tibial plateau. The tibia plateau on the inside of the leg is called the medial tibial plateau, and on the outside of the leg it is called 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 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 which 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, there 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 by preventing 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 function to stabilize the knee joint. There are two important groups of ligaments that hold the bones of the knee joint together, collateral ligaments and the cruciate ligament.

Collateral ligaments are present on either side of the knee. They function to 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 or ACL and the cruciate ligament in the back of the knee is called posterior cruciate ligament or PCL.

Muscles of the Knee

Muscles: There are two major muscles, the quadriceps and the hamstrings, which enable movement of the knee joint. The quadriceps muscles are in the front of the thigh. When the quadriceps muscles contract, the knee straightens. The hamstrings are in the back of the thigh. When the hamstring muscles contract, the knee bends.

Tendons of the Knee

Tendons are structures that attach muscles to the 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.

Conditions

Knee Pain

Knee Pain

The knee is one of the largest joints in the body, formed by the lower end of the femur, upper end of the tibia and the patella or kneecap. Several ligaments and muscles attach to the bones of the knee joint to maintain normal motion of the joint.

Knee Sprain

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.

Knee Arthritis

Knee Arthritis

Arthritis is a general term covering numerous conditions where the joint surface or cartilage wears out. The joint surface is covered by a smooth articular surface that allows pain-free movement in the joint. This surface can wear out for several reasons; often the definite cause is not known. Arthritis often affects the knee joint.

ACL Tears

ACL Tears

The anterior cruciate ligament, or ACL, is one of the major ligaments of the knee that is in the middle of the knee and runs from the femur (thighbone) to the tibia (shinbone). It prevents the tibia from sliding out in front of the femur. Together with posterior cruciate ligament (PCL) it provides rotational stability to the knee.

PCL Injuries

PCL Injuries

Posterior cruciate ligament (PCL), one of 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.

MCL Tears

MCL Tears

The medial collateral ligament (MCL) is the ligament that is located on the inner part of the knee joint. It runs from the femur (thighbone) to the top of the tibia (shinbone) and helps in stabilizing the knee.

LCL Injuries

LCL Injuries

Lateral collateral ligament (LCL) is a thin set of tissues present on the outer side of the knee, connecting the thighbone (femur) to the fibula (side bone of lower leg). It provides stability as well as limits the sidewise rotation of the knee.

Multiligament Instability

Multiligament Instability

The knee is a complex joint of the body which is vital for movement. The four major ligaments of the knee are anterior cruciate ligament, posterior cruciate ligament, medial collateral ligament and lateral collateral ligament. They play an important role in maintaining the stability of the knee.

Chondral (Articular Cartilage Defects)

Chondral (Articular Cartilage Defects)

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.

Patellofemoral Pain Syndrome

Patellofemoral Pain Syndrome

Patellofemoral pain syndrome also called runner’s knee refers to pain under and around your kneecap. Patellofemoral pain is seen in number of medical conditions such as anterior knee pain syndrome, patellofemoral malalignment, and chondromalacia patella that cause pain around the front of the knee.

Patellar Instability

Patellar Instability

Patellar (kneecap) instability results from one or more dislocations or partial dislocations (subluxations). Patella is the small piece of bone in front of the knee that slides up and down the femoral groove (groove in the femur bone) during bending and stretching movements. The ligaments on the inner and outer sides of the patella hold it in the femoral groove and avoid dislocation of the patella from the groove.

Patellar Dislocation

Patellar Dislocation

Patella (kneecap) is a protective bone attached to the quadriceps muscles of the thigh by quadriceps tendon. Patella attaches with the femur bone and forms a patellofemoral joint. Patella is protected by a ligament which secures the kneecap from gliding out and is called as medial patellofemoral ligament (MPFL).

Patella Tendon Rupture

Patella Tendon Rupture

Patella tendon rupture is the rupture of the tendon that connects the patella (kneecap) to the top portion of the tibia (shinbone). The patellar tendon works together with the quadriceps muscle and the quadriceps tendon to allow your knee to straighten out.

Procedures

Knee Arthroscopy

Knee Arthroscopy

The knee joint is one of the most complex joints of the body. The lower end of the thighbone (femur) meets the upper end of the shinbone (tibia) at the knee joint. A small bone called the patella (kneecap) rests on a groove on the front side of the femoral end. A bone of the lower leg (fibula) forms a joint with the shinbone.

ACL Reconstruction

ACL Reconstruction

The anterior cruciate ligament 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 unfortunately, it does not heal and often leads to the feeling of instability in the knee.

ACL Reconstruction Procedure – Hamstring Tendon

ACL Reconstruction Procedure – Hamstring Tendon

The anterior cruciate ligament 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 unfortunately, it does not heal and often leads to the feeling of instability in the knee.

ACL Reconstruction Patellar Tendon

ACL Reconstruction Patellar Tendon

Anterior cruciate ligament (ACL) reconstruction patellar tendon is a surgical procedure that replaces the injured ACL with thea patellar tendon. 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 the knee joint.

Meniscus Repair

Meniscus Repair

A meniscus tear is the commonest knee injury in athletes, especially those involved in contact sports. A sudden bend or twist in your knee can cause the meniscus to tear. This is a traumatic meniscal tear. Elderly people are more prone to degenerative meniscal tears as the cartilage wears out and weakens with age.

Meniscal Transplant Surgery

Meniscal Transplant Surgery

The meniscus is a C-shaped cartilage ring that acts like 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.

PCL Reconstruction

PCL Reconstruction

Posterior cruciate ligament (PCL), one of 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.

LCL Reconstruction

LCL Reconstruction

Lateral collateral ligament (LCL) is a thin set of tissues present on the outer side of the knee, connecting the thighbone (femur) to the fibula (side bone of lower leg). It provides stability as well as limits the sidewise rotation of the knee.

MCL Repair

MCL Repair

Medial collateral ligament (MCL) is one of four major ligaments of the knee that connects the femur (thigh bone) to the tibia (shin bone) and is present on the inside of the knee joint. This ligament helps stabilize the knee.

Multiligament Reconstruction

Multiligament Reconstruction

Ligaments are fibrous tissue bands that connect bones and stabilize joints. The knee joint has four major ligaments – the anterior cruciate ligament, posterior cruciate ligament, lateral collateral ligament, and medial collateral ligament.

Articular Cartilage Repair

Articular Cartilage Repair

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.

Patella Instability Surgery

Patella Instability Surgery

The knee can be divided into three compartments: patellofemoral, medial and lateral compartment. The patellofemoral compartment is the compartment in the front of the knee between the kneecap and thighbone.

Patellar Tendon Repair

Patellar Tendon Repair

Patella tendon rupture is the rupture of the tendon that connects the patella (knee cap) to the top portion of the tibia (shin bone). The patellar tendon works together with the quadriceps muscle and the quadriceps tendon to allow your knee to straighten out.

Patellofemoral Knee Replacement

Patellofemoral Knee Replacement

Traditionally, a patient with only one compartment of knee arthritis would undergo a total knee replacement surgery. Patellofemoral knee replacement is a minimally invasive surgical option that preserves the knee parts not damaged by arthritis as well as the stabilizing anterior and posterior cruciate ligaments, ACL and PCL.

Knee Osteotomy

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 and the aim is to take pressure off the damaged area and shift it to the other side of your knee with healthy cartilage.

Unicompartmental Knee Replacement

Unicompartmental Knee Replacement

Arthritis is inflammation of a joint causing pain, swelling (inflammation), and stiffness.

Osteoarthritis is the most common form of knee arthritis in which the joint cartilage gradually wears away. It most often affects older people.

Total Knee Replacement

Total Knee Replacement

The knee is made up of the femur (thighbone), the tibia (shinbone), and patella (kneecap). The meniscus, the soft cartilage between the femur and tibia, serves as a cushion and helps absorb shock during motion. Arthritis (inflammation of the joints), injury, or other diseases of the joint can damage this protective layer of cartilage, causing extreme pain and difficulty in performing daily activities.

Revision Knee Replacement

Revision Knee Replacement

Revision knee replacement surgery involves replacing part or all your previous knee prosthesis with a new prosthesis. Although total knee replacement surgery is successful, sometimes the procedure can fail due to various reasons and may require a second revision surgery.