Knee Ligaments

Name & Function  Origin & Insertion
Medial collateral ligament (MCL): stabilizes the medial aspect of the knee joint Medial femoral epicondyle & proximal tibia
Lateral collateral ligament (LCL): stabilizes the lateral aspect of the knee joint Lateral epicondyle & fibular head
Anterior cruciate ligament (ACL): prevents anterior translation of the tibia relative to the femur Lateral femoral condyle & intercondylar eminences of the tibia
Posterior cruciate ligament (PCL): prevents posterior translation of the tibia relative to the femur Medial femoral condyle & tibial sulcus

Ligament Tears in the Knee

Ligaments are strong connective tissues that bind your bones together. In your knee joint, four ligaments work to keep your upper leg (femur) and lower leg (tibia and fibula) connected as your knee bends and extends. These ligaments are located on the inside and outside of your knee (tibial collateral ligament [MCL] and fibular collateral ligament [LCL]) and crossed-formed deep within your knee joint (anterior cruciate ligament [ACL] and posterior cruciate ligament [PCL]). In sports consisting of multi-directional movement or repetitive impact to the lower body, these ligaments are challenged to maintain proper knee alignment. In fact, many of the knee injuries that occur in a variety of sports come from ligaments being pulled passed their capacity and torn, often from an inward collapse of the knee (ACL and MCL tears). If you participate in a sport, it is wise to take the time to learn to decelerate, change direction, and land without compromising the knee joint. Doing so may help you avoid experiencing an injury during a competitive event. Regardless, some may be at a higher risk than others due to structural and biomechancial differences (size and shape of the femoral notch, degree of tibial torsion and femoral anteversion, joint laxity, etc).

Reducing the Risk of Iliotibial Band Syndrome

The IT Band (Iliotibial Band) is a thick fascia and tendon-like structure that runs down the side of the thigh. Pain on the lateral aspect of the knee (lateral femoral epicondyle) is common in sports involving endurance, both competitive and recreational. Often, this comes from the IT Band uncomfortably rubbing against the side of the thigh bone (femur). This may be due to altered running mechanics, weak hip abductors, muscular imbalance or muscular tension around the hips and knees. Some proactive measures in reducing the risk of lateral knee pain include: an adequate assessment of running mechanics, frequent updates to footwear, and proper training progressions.

Limited Dorsiflexion and Knee Injuries

If you were to walk on your tippy-toes, your ankle joint (talocrural region) would be in what is called plantarflexion. Alternatively, if you were to walk on your heels, your ankle joint would be in what is called dorsiflexion. Limited range of motion in ankle dorsiflexion is an important component in altered knee biomechanics. So, if you are dealing with knee pain, the source the pain may not be in the knee itself, but instead the ankle. The ideal range of ankle dorsiflexion is 0-20 degrees. Limitions in this range of motion can alter neutral knee alignment (often valgus) and increase risk factors of ligament and cartilage tears (ACL, MCL, Meniscus), patellofemoral pain, and knee osteoarthritis. So, if you identify limitations in the ankle and are currently dealing with knee pain, increasing ankle range of motion may be an important contribution in reducing the risk of knee injury.

Sex Differences in Q-Angle

Women naturally have wider hips compared to men. This significantly impacts the angle from the hip (anterior superior iliac spine) to the knee (midpoint of the patella) and overall alignment of the knee joint. Knee collapse (valgus) may be more prevalent in individuals with a greater Q-angle and can result in “runner’s knee” from maltracking of the patella.

The normal range for women is ~17 degrees and men ~14 degrees, relative to the tibial tubercle and midpoint of the patella.