Tendinopathies in lower extremities (legs)

The probability of suffering tendinopathy in the lower extremities, in addition to being affected by a multitude of environmental factors such as exercise, is also affected by the genetic component. Variants in the genes that regulate the development and maintenance of bones, cartilage and tendons play a fundamental role in the vulnerability of certain individuals to injury.

Tendons are anatomical structures located between the muscle and the bone, whose function is to transmit the force generated by the muscle to the bone, giving rise to joint movement. They are composed mostly of collagen (30%) and water (68%), with a small proportion of elastin (2%). The amount of blood vessels in them is scarce, but increases during exercise and healing processes.

One of the main characteristics associated with the tendon is its ability to recover and return to its normal state after damage or injury. To this end, it is important to know the individual, genetic, biomechanical and environmental factors that interact with each other and that make it possible to prevent and optimize recovery from tendinopathies. Tendinopathies" are a group of pathologies that affect the tendons and which, according to the International Rheumatology Association, are classified into two large groups: inflammatory and non-inflammatory.

The most frequent lesions in the tendons of the lower extremities are:

• Achilles tendinopathy: The Achilles tendon is the largest and strongest tendon in the entire body, connects the triceps suralis to the heel, performs plantar flexion of the foot and participates in knee flexion. Associated risk factors are usually overuse, repetitive trauma, vascular disease, genetic predisposition, neuropathies and rheumatologic diseases that can cause tendon degeneration.
• Quadriceps tendon injury: The quadriceps femoris is a large, powerful muscle located in the front of the thigh. The muscles and tendons that comprise it form contractile units that stabilize the hip and knee and allow their movement. Injuries to the quadriceps muscles and tendons are common among athletes and active adults.
• Cruciate ligament rupture: The cruciate ligaments are two structures that cross inside the knee, joining the tibia to the femur and providing stability in extension and flexion movements. The anterior cruciate ligament prevents the tibia from moving forward with respect to the femur and its rupture is the most frequent. On the other hand, the posterior cruciate ligament prevents the tibia from moving backwards. The injury of these ligaments is produced after a sudden change of direction of the knee, an exaggerated deceleration or a contusion.