From aches and pain to injury, you’ve probably at one time or another experienced some sort of knee pain. For some, it may have resolved all on its own where as others may have required further medical attention. Knee pain is one of the most common musculoskeletal complaints in physically active individuals. It can be caused by trauma, overuse or by an underlying condition. The complexity and function of the knee joint make it vulnerable to injury. Identifying the root cause early on can not only speed up the recovery process but also prevent further injury from happening.
The knee is one of the largest joints in the body. It is made up of the tibiofemoral and patellafemoral joints. These two joints allow for the knee to straighten, bend, rotate and bear weight, along with the hip and ankle. In order to perform all these actions and support the entire body while doing so, the knee relies on several musculoskeletal structures. This includes bones, ligaments, tendons, muscles and cartilage. The knee is made up of four bones: femur (thigh), patella (knee cap), tibia (shin) and fibula. Knee stabilization is primary achieved from ligamentous structures (static restraints) and secondary through the muscles (dynamic restraints) that cross the knee joint. The most important ligaments of the knee include the collateral ligaments (MCL and LCL), one on the medial side and the other on the lateral side as well as two stronger ligaments (ACL and PCL) located deep inside the knee joint. The collateral ligaments provide lateral and medial stability (preventing valgus and varus forces). The cruciate ligaments prevent anterior and posterior displacement of the tibia relative to the femur as well as rotation. There are also two fibrocartilaginous menisci, the medial and lateral meniscus, that sit in the grooves between the femur and tibia and act as primary shock absorbers and increase joint congruency. The main muscles of the knee include the knee extensors also known as the quadriceps (vastus lateralis, vastus medialis, vastus intermedius, rectus femors) and the knee flexors known as the hamstrings (biceps femoris, semitendinosus, semimembranosus). In addition, the sartorius, gracilis, plantaris, popliteus, soleus and gastrocnemius muscles have a role in knee movement. The quadriceps attach to the patella via the quadriceps tendon. The patella tendon connects the patella to the tibia.