Posterior tibial tendonitis (PTT) is a common condition. It involves inflammation of the posterior tibial tendon, a structure essential for foot function. This condition can contribute to pain experienced in the knee.
Understanding Posterior Tibial Tendonitis
The posterior tibial tendon originates from a calf muscle, running down the inner side of the lower leg. It extends behind the medial malleolus (inner ankle bone) before attaching to several bones in the midfoot and arch. This tendon supports the foot’s arch and stabilizes it during walking and standing, controlling pronation (the inward rolling motion of the foot).
Posterior tibial tendonitis occurs when this tendon becomes inflamed due to overuse or repetitive stress. Symptoms include pain and tenderness along the inside of the ankle and foot, swelling in this area, and a flattening of the foot’s arch—sometimes referred to as adult-acquired flatfoot deformity. Individuals may also experience difficulty performing activities like standing on their toes.
The Biomechanical Link to Knee Pain
Dysfunctional PTT diminishes the foot’s arch support, leading to excessive pronation where the foot rolls inward excessively during weight-bearing. This altered foot alignment initiates a chain reaction up the kinetic chain, influencing the ankle, knee, and hip. The foot’s excessive inward rolling causes the lower leg bone, the tibia, to internally rotate.
This internal rotation of the tibia can then translate upward, affecting the knee joint. The knee, primarily a hinge joint, is designed for movement mostly in one plane. However, tibial internal rotation can force unnatural rotational stress on the knee. This can lead to increased stress on various knee structures, including the patellofemoral joint (under the kneecap). Abnormal tracking of the kneecap can result from this altered alignment, contributing to pain in the front of the knee.
Excessive pronation and subsequent internal rotation of the tibia can also induce internal rotation of the femur (thigh bone). This rotational imbalance at the hip and knee can place additional strain on the medial compartment of the knee. The abnormal forces generated by this misalignment can lead to discomfort and may contribute to conditions such as medial knee pain.
Associated Symptoms and Diagnostic Challenges
Beyond the primary foot and ankle pain, posterior tibial tendonitis can manifest with other symptoms that might seem unrelated to the foot. Individuals might experience ankle instability or a radiating pain that extends up the leg. The progressive flattening of the arch can also lead to difficulty with general mobility, including walking or running.
Diagnosing the link between posterior tibial tendonitis and knee pain can present a challenge for healthcare professionals. Knee pain is a very common symptom with numerous potential causes, ranging from direct injury to issues originating from the hip or spine. Therefore, clinicians might initially focus their examination solely on the knee, potentially overlooking the foot and ankle as the underlying source of the problem. This emphasizes the importance of a comprehensive assessment that considers the entire lower extremity, evaluating the biomechanics from the foot up to the hip to identify the true origin of the discomfort.
Diagnosis and Management Considerations
Diagnosing posterior tibial tendonitis involves a physical examination. A healthcare provider assesses the foot and ankle for swelling, tenderness along the tendon, movement, and arch integrity. Tests like the single-leg heel raise evaluate tendon function and arch stability. Imaging (X-rays, ultrasound, MRI) may assess the tendon’s condition and any foot deformity.
Effective management of knee pain linked to posterior tibial tendonitis centers on addressing the foot condition. Initial approaches often include conservative measures such as rest, applying ice to reduce inflammation, and using anti-inflammatory medications. Orthotics, or custom shoe inserts, are frequently prescribed to support the arch and help control excessive pronation, thereby reducing strain on the tendon and improving overall lower limb alignment. Physical therapy is also a common component of treatment, focusing on strengthening the posterior tibial muscle and surrounding foot and ankle muscles, as well as improving flexibility and gait mechanics. In some instances, bracing or immobilization with a boot may be recommended to allow the tendon to heal.