The knee is one of the largest joints in the body. The bones at the knee are the femur (thigh bone), the tibia (shin bone). There is a smaller bone that runs along the tibia called the fibula. The patella (kneecap) is the other bone that makes up the knee joint. The main ligaments in the knee are the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), and lateral collateral ligament (LCL). There is articular cartilage at the undersurface of the patella, ends of the femur and top of the tibia (tibial plateau) which helps the knee move smoothly. There is fibrocartilage called the medial meniscus and lateral meniscus. The menisci act as shock absorbers for the knee between the femur and tibia. There are bursa around the knee, which are fluid-filled sacs, that help the knee move smoothly.
The anterior cruciate ligament (ACL) is one of two “cruciate” ligaments in the knee. The other being the posterior cruciate ligament. An ACL tear is one of the most common knee injuries. The ACL is a major stabilizer in the knee and is composed of an anteriomedial and posterolateral bundle. ACL tears are more commonly non-contact injuries. A MRI confirms the presence of an ACL tear. ACL reconstruction is completed using an allograft (donor) or autograft (patient’s own tissue).
The posterior cruciate ligament (PCL) is a major stabilizer of the knee and is located in the back of the knee. A common cause of a PCL injury is during a motor vehicle accident with the knee bent and forced against a dashboard or a hyperextension injury during sports activity.
These ligaments are located on the sides of your knee. The medial collateral ligament is on the inside of your knee and the lateral collateral ligament is on the outside of your knee. They control the sideway motion of your knee. The MCL is injured when a “valgus” force is placed on your knee. The LCL is injured when a “varus” force is applied to the knee. The MCL is more commonly injured. An isolated LCL injury is rare, but can occur. There are various grades of MCL and LCL sprains. Most of the time, bracing, rest, and physical therapy are all that is needed to treat a MCL or LCL sprain. However, there are occasions when surgery is indicated.
Articular cartilage covers the ends of bones. It has a smooth, slippery surface, which allows the bones of the knee joint to slide over each other without rubbing. The articular cartilage in the knee is designed to minimize pressure and friction as you move the knee. Articular cartilage can be damaged by injury or by normal wear and tear. Depending on the extent and location of the damage, there is the possibility that the articular cartilage can heal on its own. However, articular cartilage has no direct blood supply, therefore, the chances of healing on its own is limited. There are various treatment options depending on the patient’s age, activity level and degree of articular cartilage damage.
There is a medial meniscus (located on the inner side of the knee) and lateral meniscus (located on the outside of your knee) in your knee. The menisci are a thick, fibrocartilage that are attached to the tibial plateau (the shin bone). They act as shock absorbers and are a secondary stabilizer in your knee. Meniscus tears can vary in terms of size, severity, location, tear pattern, acute or degenerative, and complete or incomplete. After considering these factors the doctor will choose to treat the injury non-operatively or surgically. The meniscus is very important to the long-term health of the knee. In the past, surgeons would simply take out part or all of an injured meniscus. But today’s surgeons know that removing the meniscus can lead to early knee arthritis. Whenever possible, they try to repair the tear. If the damaged area must be removed, care is taken during surgery to protect the surrounding healthy tissue.
Osteoarthritis (OA) of the knee is a common problem for many people. You can have primary osteoarthritis or post-traumatic osteoarthritis (from an injury). Osteoarthritis develops when the protective cartilage in your bones (articular cartilage) begin to breakdown. Osteoarthritis is typically diagnosed on X-rays; however, occasionally more advanced diagnostic testing (i.e. MRI) may be considered. There are various treatment options for osteoarthritis.
If the patella (kneecap) and femur joint surfaces becomes softened or irregular, the friction between these two bony surfaces increases. As a result, grinding or crepitus (of the patellofemoral joint) can be heard and/or felt with knee flexion and extension. There are grades of chondromalacia from softening of the cartilage to complete loss of cartilage. This condition can affect people of all ages.
The hamstring muscles are located in the back of your thigh. The hamstring is made up of the semitendinosus, semimembranosus and biceps femoris (long & short head). There are various degrees of hamstring injuries. Most of the time, hamstring injuries heal with rest, physical therapy and protected weight bearing. Surgery may be indicated for a severe hamstring injury.
Iliotibial band (ITB) syndrome is an overuse problem that is often seen in runners and cyclists. Patients typically experience pain on the outside of the knee just above the knee joint. This condition may be exacerbated by a change in terrain or an increase in mileage. Symptoms typically resolve with conservative treatment and rest. Surgery for this condition is rarely indicated.
The patellar tendon is the thick tendon that connects your patella to your tibia. This tendon can become inflamed from increase in activity. This condition is commonly seen in basketball players. This condition is also known as “jumper’s knee”.
Quadriceps tendonitis is also seen in jumping sports such as basketball. The symptoms can range from pain, tightness and swelling in the quadriceps tendon.
Patellofemoral joint (patella and the femur) instability can occur from an acute injury or be a chronic condition from an increase in joint laxity (or loose joints). Physical therapy and occasionally bracing can be beneficial. Surgery may be indicated in acute or chronic instability.
Plicae are natural synovial folds in the knee. Plica syndrome is when this normal structure in the knee becomes thickened and inflamed due to injury or overuse. Most of the time, this condition can be treated conservatively.
A popliteal cyst, also called a Baker’s cyst, is a soft, often painless bump that develops on the back of the knee. This cyst is a benign, fluid filled sac. These cysts occur most often when the knee is damaged due to arthritis, gout, or inflammation in the knee joint. Treatment is usually successful when the actual cause of the cyst is addressed. Otherwise, the cyst can reoccur over time.
Bursitis is the inflammation of the bursal sac around your knee. This inflammation can be a source or pain around the knee. There are 4 bursal sacs around the knee: suprapatellar, infrapatellar, prepatellar, pes anserine. Most of the time, bursitis is successfully treated with conservative management.