Normal Anatomy of the Knee Joint
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.
Knee pain is a common condition affecting individuals from different age groups. It not only affects movement but also impacts the quality of life of the individual. 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.
Anterior knee pain is a characterized by a 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 a variety of conditions which include runner’s knee or patellar tendinitis and chondromalacia of the patella. There is an inter-individual variation in the duration and presentation of pain.
Runner’s knee, also called patellofemoral pain syndrome refers to pain under and around your kneecap. Runner’s knee includes several medical conditions such as anterior knee pain syndrome, patellofemoral malalignment, and chondromalacia patella that cause pain around the front of the knee. As the name suggests, runner’s knee is a common complaint among runners, jumpers, and other athletes such as skiers, cyclists, and soccer players.
Osgood-Schlatter disease refers to a condition of an overuse injury that occurs in the knee region of growing children and adolescents. This is caused by inflammation of the tendon located below the knee cap (patellar tendon). Children and adolescents who participate in sports such as soccer, gymnastics, basketball and distance running are at higher risk of this disease.
The patella, also called the kneecap is a small bone present on the front of your knee joint. The underside of the patella is covered by cartilage that allows smooth gliding of the knee with movement. Overuse or misalignment of the patella can cause wear and tear of the cartilage.
Jumper’s knee, also known as “patellar tendinitis” is an inflammation of the patellar tendon that connects your kneecap (patella) to your shinbone. This tendon helps in extension of the lower leg.
A bursa is a small fluid-filled sac found between soft tissues and bones. It lubricates and acts as a cushion to decrease friction between bones when they move. 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.
- Baker’s Cyst
The knee consists of a fluid called synovial fluid, which reduces friction between the bones of the knee joint while you move your leg. Sometimes this fluid is produced in excess, resulting in its accumulation in the back of your knee. A Baker’s cyst or popliteal cyst is a fluid-filled swelling that develops into a lump behind the knee. This causes stiffness, tightness and pain behind your knee. It is commonly seen in women and people aged over 40 (although it can develop at any age).
Iliotibial band syndrome is an overuse injury resulting from the inflammation of iliotibial band. Iliotibial band is a tough group of fibers that begins at the iliac crest of hip and runs along the outside of the thigh, to get attached to the outer side of the shin bone just below the knee joint. Its function is to coordinate with the thigh muscles and provide stability the knee joint. Iliotibial band syndrome occurs when the iliotibial band and the lower outside portion of the thigh bone at the knee joint rub against each other. It commonly occurs in athletes, cyclists, and runners.
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.
Osteochondritis dissecans is a joint condition in which a piece of cartilage, along with a thin layer of the bone separates from the end of the bone because of inadequate blood supply. The separated fragments are sometimes called “joint mice”. These fragments may be localized, or may detach and fall into the joint space causing pain and joint instability.
“Shin splints” is used to describe the pain and inflammation of the tendons, muscles and bone tissue around the tibia or shin bone (a large bone in the lower leg). It occurs because of vigorous physical activity such as exercise or sports. The condition is also referred to as medial tibial stress syndrome (MTSS).
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 that may end up destroying your 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.
Damage to any of the supportive structures causes the instability of the knee joint. This can be caused by 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 bones) and sports injuries.
A bursa is a small fluid-filled sac found between soft tissues and bones. It lubricates and acts as a cushion to decrease friction between bones when they move. Bursitis refers to the inflammation and swelling of the bursa. Goosefoot bursitis or pes anserine bursitis is the inflammation of the bursa present between the tendons of the hamstring muscle and the tibia (shinbone) on the inner side of the knee.
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.
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 (thigh bone) to the tibia (shin bone). 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.
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. Medial collateral ligament (MCL) injury can result in a stretch, partial tear, or complete tear of the ligament. Injuries to the MCL commonly occur because of a pressure or stress on the outside part of the knee. Anterior cruciate ligament (ACL) may be torn along with a MCL injury.
The medial collateral ligament (MCL), a band of tissue present on the inside of your knee joint, connects your thigh bone and shin bone (bone of your lower leg). The MCL maintains the integrity of the knee joint and prevents it from bending inward.
The knee is one of the most complex and largest joint in the body, and is more susceptible to injury. Meniscal tears are one among the common injuries to the knee joint. It can occur at any age, but are more common in athletes playing contact sports.
Meniscus tear is the commonest knee injury in athletes, especially those involved in contact sports. A suddenly bend or twist in your knee cause the meniscus to tear. This is a traumatic meniscus tear. Elderly people are more prone to degenerative meniscal tears as the cartilage wears out and weakens with age. The two wedge-shape cartilage pieces’ present between the thighbone and the shinbone are called meniscus. They stabilize the knee joint and act as “shock absorbers”.
The knee is a complex joint which consists of bone, cartilage, ligaments and tendons that make joint movements easy and at the same time more susceptible to various kinds of injuries.
Knee problems may arise if any of these structures get injured by overuse or suddenly during sports activities. Pain, swelling, and stiffness are the common symptoms of any damage or injury to the knee.
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. An injury resulting in tear of one or more ligaments of the knee thus affects knee stability. Such injuries occur because of direct blow to the knee, or a fall from a height, or motor vehicle trauma. Multiple ligament knee injuries are common in athletes involved in contact sports such as soccer, football and basketball. Patients with multi-ligament knee injuries may experience pain, swelling, limited range of motion, injuries to nerves and arteries of the leg, and knee instability.
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.
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).
Posterior cruciate ligament (PCL), one of four major ligaments of the knee are 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.
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 less capacity to repair itself. Once the cartilage is torn it will not heal easily and can lead to degeneration of the articular surface, leading to development of osteoarthritis.
Patellar (kneecap) instability results from one or more complete or partial dislocations (subluxations). The patella is a 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 its dislocation from the groove.
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 knee cap and thigh bone. The medial compartment is the area on the inside portion of the knee, and the lateral compartment is the area on the outside portion of the knee joint. 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.
The knee cap or patella is the largest sesamoid bone in the body and one of the components of the knee joint, present at the front of the knee. 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. The knee cap protects the knee and provides attachment to various muscle groups of the thigh and leg. Fracture of knee cap is rare and is more common in adult males.
The patella (kneecap) is a small bone that shields your knee joint. It is found in front of your knee, in a groove called the trochlear groove that sits at the junction of the femur (thighbone) and tibia (shinbone). Articular cartilage present below the patella and end of the femur cushion and help the bones glide smoothly over each other when the legs move. This joint is stabilized and supported by a network of soft tissues. The medial patellofemoral ligament (MPFL) connects to the inner side of the patella and helps to keep it from slipping away from the knee. Damage to this ligament leads to patellar dislocation.
Quadriceps tendon is a thick tissue located at the top of the kneecap. The quadriceps tendon works together with the quadriceps muscles to allow us to straighten our leg. The quadriceps muscles are the muscles located in front of the thigh.
Patella tendon rupture is the rupture of the tendon that connects the patella (kneecap) 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.
The knee joint is formed by the union of two bones, namely the femur (thigh bone) and the tibia (lower leg bone). At the junction of these two bones is a cartilage called the meniscus, which acts as a shock absorber. There are two menisci – the lateral and medial menisci. The lateral meniscus is the outer meniscus of the knee joint and gives a cushioning effect during weight bearing activities. Lateral meniscus syndrome is characterized by an injury caused by the tearing of the cartilage tissue or a rare case of a congenital abnormality called a discoid meniscus, which results in knee pain.
Medial meniscal injuries are usually considered as either traumatic or degenerative. Whilst degenerate tears may present with a gradual history of increasing symptoms, traumatic injuries will usually occur as the knee is extended and rotated from a flexed position against resistance. This may occur as a single event during a sporting endeavor or during a period of unaccustomed squatting such as laying flooring or playing with children. The most commonly injured area is the posterior horn.
Tibial eminence spine avulsion fracture is avulsion (tear away) of the tibial eminence (an extension on the bone for attachment of muscles) which most commonly involves the anterior cruciate ligament (ACL) insertion site. This injury represents the childhood equivalent of the anterior cruciate ligament (ACL) rupture and may occur because of abnormal outward bending or twist, injuries caused by sudden halt of moving joints, excessive flexion (bending inwards) and internal rotation as happens in skiing and in motor vehicle accidents.
Osteonecrosis is a condition in which death of a section of bone occurs because of lack of blood supply to it. It is one of the most common causes of knee pain in older women. Women over the age of 60 years of age are commonly affected, three times more often than men.
Angular deformities of the knee are common during childhood and usually are variations in the normal growth pattern. Angular deformity of the knee is a part of normal growth and development during early childhood. Physiologic angular deformities vary with age
Knee Arthroscopy is a common surgical procedure performed using an arthroscope, a viewing instrument, to consider the knee joint to diagnose or treat a knee problem. It is a relatively safe procedure and most the patient’s discharge from the hospital on the same day of surgery.
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 is a commonly performed surgical procedure and with recent advances in arthroscopic surgery can now be performed with minimal incision and low complication rates.
The advancements in arthroscopic surgery make it easy for surgeons to see and work on knee structures through small incisions. Repair of the torn ligament can be performed at the same time as the diagnostic arthroscopy with fewer surgical risks.
The surgery can usually be done as an outpatient procedure which means you may be discharged to go home on the same day as the procedure.
Anterior cruciate ligament (ACL) reconstruction hamstring method is a surgical procedure that replaces the injured ACL with a hamstring tendon. Anterior cruciate ligament is one of the four major ligaments of the knee that connects the femur (thigh bone) to the tibia (shin bone) and helps stabilize your knee joint. Anterior cruciate ligament prevents excessive forward movement of the lower leg bone (the tibia) in relation to the thigh bone (the femur) as well as limits rotational movements of the knee.
Anterior cruciate ligament (ACL) reconstruction patellar tendon is a surgical procedure that replaces the injured ACL with a patellar tendon. Anterior cruciate ligament is one of the four major ligaments of the knee that connects the femur (thigh bone) to the tibia (shin bone) and helps stabilize the knee joint. Anterior cruciate ligament prevents excessive forward movement of the lower leg bone (tibia) in relation to the thigh bone (femur) as well as limits rotational movements of the knee.
Total knee replacement, also called total knee arthroplasty, is a surgical procedure in which the worn out or damaged surfaces of the knee joint are removed and replaced with artificial parts. The knee is made up of the femur (thigh bone), the tibia (shin bone), 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. Your doctor may recommend surgery if non-surgical treatment options have failed to relieve the symptoms.
Unicompartmental knee replacement is a minimally invasive surgery in which only the damaged compartment of the knee is replaced with an implant. It is also called a partial knee replacement. The knee can be divided into three compartments: patellofemoral, the compartment in front of the knee between the knee cap and thigh bone, medial compartment, on the inside portion of the knee, and lateral compartment which is the area on the outside portion of the knee joint.
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 require a second revision surgery.
Custom fitted total knee arthroplasty 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 custom 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. The implants are then designed specifically to match the natural shape of the articulating surfaces of the patient’s knee based upon the MRI. Unlike other knee replacement surgeries, custom fitted total knee replacement can also be used for severe knee arthritis.
Robotic assisted partial knee surgery is an innovative alternative to the conventional surgical procedure in patients suffering from degenerative knee diseases such as osteoarthritis. It is performed using robotic-arm technology that allows the surgeon to precisely perform the surgery through a smaller incision as compared to traditional surgery.
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 patients to go home the same day of the surgery. This is made possible with recent advances such as improved perioperative anesthesia, minimally invasive techniques and initiation of rehabilitation protocols soon after surgery. Outpatient total knee replacement is considered when your vital signs are stable, such as heart and respiratory rate, blood pressure and temperature during your post-operative physical therapy session.