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 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.
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.
Damage to any of these supportive structures causes instability of the knee joint. An unstable knee can be caused by the sudden twisting of the knee, tears of the meniscus, ligament or capsule, osteoarthritis of the knee (wear and tear of the cushioning cartilage tissue between the bones) and sports injuries.
Meniscal tears are one of the most common 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.
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.
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). They play an important role in maintaining the stability of the knee. A multiligament injury is a tear in one or more ligaments of the knee, which affects the knee stability.
The quadriceps can rupture after a fall, direct blow to the leg and when you land on your leg awkwardly from a jump. Quadriceps tendon rupture most commonly occurs in middle-aged people who participate in sports that involve jumping and running. Other causes include tendonitis (inflammation of quadriceps tendon), diseases such as rheumatoid arthritis, diabetes mellitus, infection and chronic renal failure, which weaken the quadriceps tendon.
An iliotibial band is a tough group of fibers that runs from the iliac crest of the hip along the outside of the thigh, till the outer side of the shinbone, just below the knee joint. Its function is to coordinate with the thigh muscles and provide stability to the knee joint.
Patellar dislocation occurs when the patella moves out of the patellofemoral groove, (trochlea) onto the bony head of the femur. If the kneecap partially comes out of the groove, it is called subluxation; if the kneecap completely comes out, it is called dislocation (luxation).
The 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 your body during activities such as running and jumping. Articular cartilage does not have a direct blood supply to it, so has less capacity to repair itself.
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. Once damaged, these soft structures are unable to keep the patella (kneecap) in position.
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.
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.
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.
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.
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.
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.
Osgood-Schlatter disease refers to a condition in older children and teenagers caused by excessive stress to the patellar tendon (located below the kneecap). Participants in sports such as soccer, gymnastics, basketball, and distance running are at higher risk for this disease.
Knee replacement, also called knee arthroplasty, is a surgical procedure in which the worn-out or damaged surfaces of the knee joint are removed and replaced with artificial implants. Any resulting fractures or breaks in the bone around the implant are called periprosthetic knee fractures.
e lower leg is made up of two long bones called the tibia and fibula that extend between the knee and ankle and help form the ankle joint and knee joint. The tibia or shinbone is the larger of the two bones and is one of the major bones of the lower leg. It bears most of the body’s weight and plays a crucial role in balancing body weight when standing and walking.
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.
Meniscal root tears are characterized as soft tissue or bony root avulsion injuries or radial tears located within 1 cm of meniscus root attachment. They can be either a tear which disconnects the root area completely from the body of the meniscus (complete radial tear) or a disruption of the meniscus attachment directly from the bone (true meniscus root tear) that can cause the whole meniscus to lose its capacity to safeguard the underlying cartilage.
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.
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.
Total knee replacement is a very successful surgical treatment for knee arthritis. Over the years, minimally invasive knee replacement surgical techniques have been developed to lessen tissue trauma and improve patient outcomes. This minimally invasive approach involves much smaller incisions than the usual 10-12 inch incisions used in the traditional knee replacement and spares the quadriceps muscle and tendon, which control bending of the knee, from being cut to access the knee joint.
Patient Specific Knee Replacement is a newer technology in total knee replacement surgery. It is an advanced procedure using an individualized patient-specific knee implant for replacement of all three components of the knee. The difference with patient specific knee replacement from other knee replacement surgeries is the use of an MRI scan prior to the surgery that provides a clear view of the shape and structure of the different components of the joint.
Posterolateral corner injury is damage or injury to the structures of the posterolateral corner. The structures of the posterolateral corner include the lateral collateral ligament, the popliteus tendon, and the popliteo-fibular ligament. Injuries to the posterolateral corner most often occur with athletic trauma, motor-vehicle accidents, and falls.
The meniscus is a soft, fibrous disk of cartilage in your knee joint that sits between the femur (thighbone) and the tibia (shinbone). Also called fibrocartilage, it cushions and stabilizes the joint, acting as a smooth surface for the joint to move on to prevent wear and tear. There are two menisci - one on each side of your knee joint.
Revision knee replacement surgery involves replacing a 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.
Short-stay and fast-track knee replacement is a minimally invasive surgical procedure in which the worn-out or damaged surfaces of the knee joint are removed and replaced with prostheses. It is a multidisciplinary approach for knee treatment in which patients are mobilized as early as possible to achieve a faster and better recovery without compromising quality.
Reoperation of a total knee replacement to correct a loosened prosthesis as a result of wear and tear of the prosthetic joint surfaces is known as correction of a loose knee replacement. This procedure involves a complete or partial exchange of prostheses implanted during the original total knee replacement with new prostheses.
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.
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.
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.
Total knee replacement is the surgical treatment for knee arthritis, where the damaged knee is removed and replaced with an artificial knee implant. Traditionally performed as an inpatient procedure, total knee replacement surgery is now being conducted on an outpatient basis, allowing you to go home on the same day of the surgery.
Meniscus root repair is a surgery performed to repair a torn meniscus root. Meniscal repair may be performed either by open surgery under direct vision or minimally invasively using an arthroscope that can be inserted into the knee through a very small key-hole incision to locate and repair the damaged meniscus.
Arthroscopic knee ligament reconstruction is a surgical procedure to correct a torn knee ligament by replacing the ligament with a healthy tendon tissue using an arthroscope.
Physical therapy is an exercise program that helps you to improve movement, relieve pain, encourage blood flow for faster healing, and restore your physical function and fitness level. It can be prescribed as an individual treatment program or combined with other treatments.
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.