Overall Fitness And Knee Injury
Physical fitness is related integrally to the development of knee problems. The same activity such as climbing stairs may cause pain from patellofemoral compression for someone who is physically unfit, but not for someone else . Obesity is another major contributor to knee pain. For instance, a 30-year-old woman who weighed 120 lb at age 18 years, before her three pregnancies, and now weighs 285 lb, had added 660 lb of force across her patellofemoral joint with each step.
Ligaments Of The Knee
The four main ligaments in the knee are:
- Medial Collateral Ligament: found on the inner side of the knee
- Lateral Collateral Ligament: found on the outer side of the knee
- Anterior Cruciate Ligament: found in the middle of the knee
- Posterior Cruciate Ligament: found in the middle of the knee
The collateral and cruciate ligaments are generally considered to be the main ligaments of the knee but there are a few others that work alongside them, although not everyone has all of them!
There are other knee ligaments are:
- Transverse Ligament: joins the medial and lateral meniscus
- Anterior Meniscofemoral Ligament: joins the lateral meniscus to the medial femoral condyle
- Posterior Meniscofemoral Ligament: joins the lateral meniscus to the medial femoral condyle
- Coronary Ligaments: join both menisci to the tibia
- Oblique Popliteal Ligament: attaches to one of the hamstring tendons
- Arcuate Popliteal Ligament: joins the fibula to the tibia and femur
What Are Knee Ligaments
There are 4 major ligaments in the knee. Ligaments are elastic bands of tissue that connect bones to each other and provide stability and strength to the joint. The four main ligaments in the knee connect the femur to the tibia , and include the following:
Anterior cruciate ligament . The ligament, located in the center of the knee, that controls rotation and forward movement of the tibia .
Posterior cruciate ligament . The ligament, located in the back of the knee, that controls backward movement of the tibia .
Medial collateral ligament . The ligament that gives stability to the inner knee.
Lateral collateral ligament . The ligament that gives stability to the outer knee.
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How Are Knee Sprains And Tears Classified
A healthcare provider will grade your injury by how severe it is and what symptoms you have:
- Grade 1: A grade 1 injury to a knee ligament is a minor sprain. The ligament is overstretched or just slightly torn. With a grade 1 knee strain, youll have minimal pain, swelling or bruising. Youll still be able to put weight on the affected leg and bend the knee.
- Grade 2: A grade 2 knee sprain is a moderate tear of the ligament. Signs include bruising, swelling and some pain. With a grade 2 injury, youll have some difficulty putting weight on the leg or bending the knee.
- Grade 3: A grade 3 injury is a complete tear or rupture of the knee ligament. Grade 3 injuries often involve more than one knee ligament. With this level of injury, you will experience severe bruising, swelling and pain. You wont be able to put weight on the leg or bend the knee.
Muscles And Tendons Of The Knee
Many muscles affect the knee, but the main muscles that allow for the knee to perform its main functions are:
- Quadriceps: A group of 4 muscles that sits on the front of the thigh. These muscles are responsible for allowing the knee to straighten. This movement is necessary for standing from a seated position, bringing your leg forward when walking, and kicking a ball! The two patellar tendons attach the quad to the patella. These tendons can also rupture during sports.
Quadriceps Muscle diagram
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The Muscles In The Back Of The Knee
Hamstring Muscle diagram
- Gastrocs: A group of 2 muscles that sit in on the lower leg backside that works in tandem with the hamstrings to cause the knee to bend. The gastroc or calf muscle can be strained and torn during sports like tennis or basketball. The athlete will feel a “pop’ in the calf.
Calf Muscle Diagram
- Tendons attach the knee muscles to the bone. The two patellar tendons can also be prone to overuse and the development of patellar tendonitis. Jumper’s knee is common in the knee with athletics.
All of these muscles also have functions at different joints such as the hip and the ankle. Injuries to these structures, such as a pull or strain, will cause pain when activating the muscle and, if severe enough, will cause significant weakness.
What Are The Ligaments Of The Knee
There are two main types of ligaments in your knee:
- Collateral ligaments: The two collateral ligaments are like straps on each side of your knee. The medial collateral ligament is on the inner side of your knee. It attaches the thigh bone to the shin bone . The lateral collateral ligament is on the outer side of your knee. It connects your femur to your calf bone . The collateral ligaments prevent the knee from moving side to side too much.
- Cruciate ligaments: The two cruciate ligaments are inside your knee joint and connect your femur to your tibia. They cross each other to create an X. The anterior cruciate ligament is located toward the front of the knee. The posterior cruciate ligament is behind the ACL. The cruciate ligaments control the way your knee moves front to back.
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Muscles Around The Knee
The muscles around the knee help to keep the knee stable, well aligned, and moving. There are two main muscle groups around the knee: the quadriceps and the hamstrings. The quadriceps are a collection of 4 muscles on the front of the thigh and are responsible for straightening the knee by bringing a bent knee to a straightened position. The hamstrings are a group of 3 muscles on the back of the thigh that provide the opposite motion by bending the knee from a straightened position.
The iliotibial band is a broad tendinous extension of the tensor fascia lata and gluteus maximus that also helps to stabilize the knee.
What Is A Knee Ligament Injury
Knee ligaments are the short bands of tough, flexible connective tissue that hold the knee together. Knee ligament injuries can be caused by trauma, such as a car accident. Or they can be caused by sports injuries. An example is a twisting knee injury in basketball or skiing.
The knee has 4 major ligaments. Ligaments connect bones to each other. They give the joint stability and strength. The 4 knee ligaments connect the thighbone to the shin bone . They are:
- Anterior cruciate ligament . This ligament is in the center of the knee. It controls rotation and forward movement of the shin bone.
- Posterior cruciate ligament . This ligament is in the back of the knee. It controls backward movement of the shin bone.
- Medial collateral ligament . This ligament gives stability to the inner knee.
- Lateral collateral ligament . This ligament gives stability to the outer knee.
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Sacrospinous And Sacrotuberous Ligaments
The next two ligaments are particularly famous for transforming the lesser and greater sciatic notches into the lesser and greater sciatic foramina. These are the sacrospinous and sacrotuberous ligaments. The former is a thin, triangular, fibrous band that extends from the margins of the coccyx and sacrum to the spine of the ischium. It is often referred to as the degenerate component of the coccygeus muscle and it also travels anterior to the larger, more robust sacrotuberous ligament.
The latter ligament has several attachments to the posterior sacroiliac ligaments, lower transverse tubercles of the sacrum, the posterior superior iliac spine, the proximal part of the coccyx and the lower lateral margins of the sacrum. It then travels across the sciatic notch to complete its connection to the ischial tuberosity and continues along the ramus of the ischium as the falciform process. Of note, the falciform integrates with the fascia of the pudendal neurovascular structures. The sacrotuberous ligament also serves as a point of attachment for the most caudal fibers of gluteus maximus. Additionally, the most superficial fibers of this ligament integrate with the tendon of biceps femoris and continue with this structure to its insertion.
Knee Anatomy Function And Common Problems
The knee joint is a synovial joint which connects the femur , the longest bone in the body, to the tibia . There are two main joints in the knee: 1) the tibiofemoral joint where the tibia meet the femur 2) the patellofemoral joint where the kneecap meets the femur. These two joints work together to form a modified hinge joint that allows the knee to bend and straighten but also to rotate slightly from side to side.
The knee joint is the largest joint in our body. It is vulnerable to injury as it bears an enormous amount of pressure while providing flexible movement. When we walk, the load on our knees is equal to 1.5 times our body weight. When climbing stairs it is equal to 3-4 times our body weight. When we squat, the load on our knees increases to about 8 times our body weight!
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The Joint Capsule Of Femorotibial Articulation
This strong flat band arises from the femur just lateral to the medial head of the gastrocnemius muscle. Distally it extends to the caudal border of the medial border to the tibia bone of a dog.
The joint capsule of femorotibial articulation attaches to the margin of the tibial articular surface. It also attaches to the convex border of the menisci and the cruciate ligaments. The cranial part of the joint capsule is thin and consists of a synovial layer only. But the caudal part is stronger and have a connection with the oblique popliteal ligament.
Here in the joint capsule of the femorotibial joint, you will also find two synovial sacs. But the femorotibial sacs are smaller than that of femorpatellar. Each of these femorotibial sacs divides by the menisci into femoromeniscal and tibiomeniscal parts.
The menisci develop in the fibrous layer of the capsule, and the two parts communicate primarily around their concave, sharp-edge axial borders.
Again, you will find a transverse communication between the lateral and medial border condyloid part of the joint.
How Is A Knee Ligament Injury Diagnosed
In addition to a complete medical history and physical examination, diagnostic procedures for a knee ligament injury may include the following:
X-ray. A diagnostic test that uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film to rule out an injury to bone instead of, or in addition to, a ligament injury.
Magnetic resonance imaging . A diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body can often determine damage or disease in bones and a surrounding ligament or muscle.
Arthroscopy. A minimally-invasive diagnostic and treatment procedure used for conditions of a joint. This procedure uses a small, lighted, optic tube that is inserted into the joint through a small incision in the joint. Images of the inside of the joint are projected onto a screen used to evaluate any degenerative and/or arthritic changes in the joint to detect bone diseases and tumors to determine the cause of bone pain and inflammation.
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How Can A Healthcare Provider Tell If Ive Injured A Knee Ligament
If you seek medical attention for a knee injury, a healthcare provider may:
- Ask you about your symptoms and when they started.
- Conduct a physical exam by looking at the injured knee, assessing how it moves and comparing it to the other knee.
- Order imaging tests if necessary, such as MRI, to take pictures of the knee ligaments.
- Take X-rays to rule out a broken leg bone, kneecap or other problem.
How Are Cruciate Ligaments Injured
The anterior cruciate ligament is one of the most common ligaments to be injured. The ACL is often stretched and/or torn during a sudden twisting motion . Skiing, basketball, and football are sports that have a higher risk of ACL injuries.
The posterior cruciate ligament is also a common ligament to become injured in the knee. However, the PCL injury usually occurs with sudden, direct impact, such as in a car accident or during a football tackle.
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When Should I See A Healthcare Provider For A Sprained Knee
Damage to a knee ligament can weaken the knee joint, increasing the chances that youll injure yourself again.
Talk to a healthcare provider if you have:
- Looseness or weakness in the knee.
- Loss of feeling in the knee or leg.
- Pain on the inside or outside of the knee.
- A popping or snapping noise.
- Repeat knee injuries.
- Swelling around the knee joint.
- Trouble putting weight on that leg.
A note from Cleveland Clinic
Knee ligaments are bands of tissue that connect the thigh bone in the upper leg to the lower leg bones. There are four major ligaments in the knee: ACL, PCL, MCL and LCL. Injuries to the knee ligaments are common, especially in athletes. A sprained knee can range from mild to severe. Talk to a healthcare provider if you have a severe knee injury or repeat injuries. Proper diagnosis and treatment can help prevent pain and future injuries.
How Do The Anatomy Of Knee And Lower Leg Affect Movement
The knee is a hinge joint that sits between the thigh and the shin. It functions the same as a hinge on a door and sometimes gets a creaky as a hinge can. This joint allows the legs to bend and straighten, necessary for walking, going up and downstairs, going from sitting to standing, running, and jumping. The knee’s anatomy consists of many structures from the bones, tendons, and ligaments to the cartilage and muscles to help the knee function.
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Bones Around The Knee
There are three important bones that come together at the knee joint:
A fourth bone, the fibula, is located just next to the tibia and knee joint, and can play an important role in some knee conditions.
The tibia, femur, and patella, all are covered with a smooth layer of cartilage where they contact each other at the knee joint. There is also a small bone called a fabella, that is often located behind the knee joint.
A type of bone called a sesamoid bone , the fabella is of little consequence to the function of the knee joint. It is only found in about 25% of the population.
Knee Ligament Injury Care At Uw Medicine
Choosing UW Medicine for your orthopedic and sports medicine care means getting access to some of the most experienced physicians and surgeons in the country, many of whom have spent years caring for elite and high-level athletes who have ligament and meniscus injuries. The UW Medicine team helps care for athletes from the Seattle Seahawks, Washington Huskies and many youth sports leagues.
Treatment plans for most knee injuries rely on making an accurate diagnosis with a focus on managing pain and rehabilitation to regain function. Surgery may also be necessary to lead to full, functional recovery. Our goal is to restore and optimize the function of your knee so you can get back to the activities you enjoy.
Knee and other sports injuries can be evaluated at any of our sports medicine clinics or orthopedic surgery locations across the Puget Sound region. Physicians and surgeons at the Sports Medicine Center at Husky Stadium are specifically trained in treating elite and high-level athletes of all ages. Most UW Medicine physicians train the next generation of doctors, so you can expect to receive care from doctors who have a wealth of experience and also drive future research and education within sports medicine.
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What Are The Parts Of The Knee That Can Be Torn
Four common ligaments of the knee are the Lateral Collateral Ligament , the Posterior Cruciate Ligament , and the two that are the most common to the public the Medial Collateral Ligament and the Anterior Cruciate Ligament . The Patellar Ligament, referred to as the patellar tendon, is the ligament that connects the bottom of the knee cap and the top of the shin . Right above the patella is the quad tendon that connects the patella to the quads . The meniscus is split into the medial and lateral aspects of the knee. These are cartilaginous pillows that rest on top of the tibia. The meniscus provides a cushion for the thigh bone to rest on the lower leg or shin.
Cartilage Of The Knee Joint
There are two main types of cartilage in knee anatomy: articular cartilage and the meniscus.
- Articular cartilage covers the bones’ ends and allows for the bones to slide and glide on each other without friction. This is the stuff you need to keep from getting the creaking and cracking of the joints. When this starts to wear down, arthritis will set in. Sometimes this cartilage is damaged with an ACL tear. The amount of trauma from the ACL injury can lesions to the cartilage of the joint or bones of the knee. This can be addressed during the surgical procedure.
Image of articular cartilage and meniscus
- Meniscus: 2 thick pieces of cartilage that sit on the tibia between the femur and tibia. These are C-shaped that allow for improved congruence of the joint. Tears in these structures can cause pain, swelling, and sometimes catching and locking the knee joint. During surgery, the meniscus can be repaired or debrided. This is usually determined by the age of the patient, where the tear occurred and the amount of damage to the meniscus. To learn more, Read this Article about Meniscus Injuries.
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