Knee pain and knee injuries are common in sports, and from the weekend warriors to the middle aged who may have worked on their feet many hours a day year after year.
Today I am going to try to help you understand some of the structures in the knee that are commonly injured.
The knee joint itself is a fairly simple joint. It is a hinged joint that moves in one plane. Basically, it flexes or extends. There is no rotational movement of the joint itself.
As simple as that sounds, there are many muscles, tendons, ligaments and cartilage structures in and around the knee that can be injured.
Breaking these structures down a little bit depending on where you have pain may determine what structure is injured. Refer to the diagram for the location of structures.
Musculature: You have muscles above and below the knee joint that move the knee. These muscles can be strained, and depending on where the strain is, it can feel like a pain in your knee. Most of the time a strain will be above or below the knee joint. The major muscles above the knee are the quadriceps in front and the hamstrings in the back. Below the knee is the gastrocnemius (calf muscle).
Tendons: Tendons attach these above muscles to the bones of the knee joint. These tendons often become overused leading to inflammation and causing pain near or at the joint on these tendons. The most common tendons injured are the patellar tendon just below the patella (kneecap), or the quadriceps tendon just above the patella. Hamstring tendons on the posterior (rear) knee can also cause some pain if injured.
Ligaments: Holding the bones of the knee together are ligaments. There are four major ligaments of the knee that are commonly injured. The medial collateral ligament (MCL) and the lateral collateral ligament (LCL) give stabilization to the knee from the sides. These are usually injured from a blow or fall that forced the knee inward or outward stretching or tearing these ligaments. The anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) are inside the knee holding the femur and tibia together. The ACL is injured in sports many times when the foot is planted, and the athlete tries to quickly change directions, causing a shearing force on the ligament when the upper part of the knee is moving one way and the lower part is not moving. This causes the ligament to rupture. The ACL or PCL can also be injured during a blow to the knee that causes too much force to these ligaments.
Cartilage: The bones of the knee are covered with articular cartilage that protects the bones from rubbing on each other. Between these bones are a meniscus. There is a lateral and medial meniscus, which are also cartilage that act as a cushion in the knee between the bones. Injuries to the meniscus usually involves tearing of the meniscus. At times this can be repaired, but many times the tear has to be cut out, leaving you with less meniscus in the knee. Over time the articular cartilage can wear, which leads to arthritis.
To keep your knee as injury free as possible, it is important to keep the surrounding musculature as strong as possible and maintain flexibility. Some exercises to consider for strength include squats, lunges, step ups, knee extension and flexion with resistance, and calf raises. Stretches to the hamstrings, quadriceps and calf also are important.
With this overview of the knee, hopefully you have a better understanding of some of the structures and injuries. If you feel that you have injured any of these structures, see your physician for proper diagnosis and treatment. In the next few articles, we will look more in depth at a few of the injuries that occur more frequently.