The knee is the largest joint in the human body and one of the most common source of arthritis, disease processes, and injuries. Classified as a pivotal hinge joint, the knee allows for straightening and bending in one direction, with some twisting from side-to-side. (screw home mechanism). The knee joint is made up of bones, cartilage, ligaments, tendons, bursae, and meniscus. The knee is a hinge at the junction of two bones, the femur (thigh bone) and tibia (shin). The ends of the bones are covered with a thick cushion of hard, white cartilage and protected by 4 ligaments that keep the knee centered. Knee cartilage damage or worn cartilage causes the underlying bones to rub together producing knee pain and inflammation typical of knee arthritis.
Once the knee joint is damaged by arthritis, injury, or disease, our normal function becomes impaired and mechanical breakdown of the knee joint starts to occur. Ultimately, this results in knee pain, muscle weakness, and limited movement.
Anterior Cruciate Ligament (ACL) Injury
Anterior Cruciate Ligament (ACL) Ligaments are tough, non-stretchable rope-like structures that stabilize our bones where they meet at our joints. The anterior cruciate ligament (ACL) is one of the four ligaments that provide stability and centering to our knee joint. The ACL is particularly important in providing rotational stability and is often damaged during sports related activities that require pivoting. An injury to the ACL can also result from either direct contact to the knee which causes excessive angulation of the knee joint or non-contact planting and pivoting with bending of the knee. When the ACL is torn, patients may feel or hear a “pop” in the knee joint. The knee most often gives out and may quickly swell preventing movement and weight bearing.
Degenerative Joint Disease (DJD) or Osteoarthritis (OA)
Osteoarthritis or “wear and tear arthritis” is very common in the knee joint since the cartilage simply wears out over time. When this cartilage wears away, the knee begins rubbing on the femur, tibia, and patella, ultimately causes severe pain and hip disability. The most frequent reason for osteoarthritis is genetic, since the durability of each individual’s cartilage is based on genetics. If your parents have arthritis, you may also be at risk of suffering from degenerative joint disease.
Lateral Collateral Ligament (LCL) Injury
Ligaments are tough, non-stretchable rope-like structures that stabilize our bones where they meet at our joints. The lateral collateral ligament (LCL) is one of the four ligaments that provide stability and centering to our knee joint. The LCL is particularly important in providing rotational stability and helps to prevent widening of the outside of the knee. It spans the distance from the end of the femur (thigh bone) to the top of the fibula (thin, outer, lower leg bone) and is on the outside of the knee. Most LCL injuries happen from a direct force from the side of the knee, causing moderate to severe knee pain and ligament injury which often leads to knee surgery. It is much less frequent ligament injury than the medial collateral ligament (MCL) but commonly occurs with other ligament injury to the knee.
Medial Collateral Ligament (MCL) Injury
The medial collateral ligament (MCL) is one of the four ligaments that provide stability and centering to our knee joint. The MCL helps to provide rotational stability and helps to prevent widening of the outside of the knee. The MCL spans the distance from the end of the femur (thigh bone) to the top of the tibia (shin bone) and is on the inside of the knee joint. The medial collateral ligament resists widening of the inside of the joint, or prevents “opening-up” of the knee. Most MCL injuries happen from a direct force from the side of the knee, causing moderate to severe knee pain and ligament injury which often leads to knee surgery. It is the more common ligament injury than the lateral collateral ligament (LCL) but commonly occurs with other ligament injury to the knee.
The meniscus works like a shock absorber in the knee joint and is made of a very strong substance called fibrocartilage. It helps to prevent and protect the knee from early arthritis and wearing out by this shock absorptive property. A large percentage of our body weight is distributed through the meniscus as we walk, run, and jump. The meniscus adds to the stability of the knee joint by helping the shape of the femur or thigh bone conform to the tibia or leg bone. The meniscus also plays a role in the nourishment of the joint cartilage that covers the bones in the joint.
Posterior Cruciate Ligament (PCL) Injury
Similar to the ACL in nature, the PCL is broader and stronger than the ACL. It connects the femur (thigh bone) to the tibia (shin bone). Its function is to prevent the posterior translation of the tibia relative to the femur and is important in providing rotational stability and is often damaged during sports-related activities that require pivoting. A forceful hyperextention of the knee or a direct blow just below the knee cap will disrupt the PCL and cause knee pain and PCL Injury. It has been reported that there is only a 2% incidence of isolated PCL tears.
Bilateral Total Knee Replacement
Cartilage Injury Treatments
PCL, LCL, and/or MCL Repair
Partial Knee Replacement
Revision Knee Surgery
Total Knee Replacement