Achilles tendinopathy is a common condition affecting the Achilles tendon, a strong band of tissue located at the back of the lower leg. This disorder involves a combination of changes within the tendon, typically resulting from overuse and prolonged stress. It can affect both athletes and individuals who do not participate in sports. The condition often leads to pain, stiffness, and limitations in physical activity.
What is Achilles Tendinopathy?
The Achilles tendon is the largest and strongest tendon in the human body, connecting the calf muscles (gastrocnemius and soleus) to the heel bone (calcaneus). Its primary function is to allow for plantarflexion of the foot, which is the movement of pointing the toes downward, and it plays a significant role in walking, running, climbing stairs, and jumping. The tendon’s fibers spiral as they descend, a design that helps transmit force efficiently to the foot during movement.
Achilles tendinopathy refers to a degenerative condition of this tendon, meaning it involves a breakdown of tendon fibers rather than primarily inflammation. While historically called “tendinitis,” current understanding emphasizes degenerative changes within the tendon structure, such as collagen fiber disorientation and thinning, with an absence of acute inflammatory cells in chronic cases. This process can lead to microscopic tears and structural changes over time.
There are two main types of Achilles tendinopathy, categorized by their location on the tendon. Non-insertional Achilles tendinopathy affects the middle portion of the tendon, typically 2 to 6 centimeters above where it attaches to the heel bone. In this type, the tendon fibers in the mid-portion may develop tiny tears and begin to break down, leading to thickening and swelling.
Conversely, insertional Achilles tendinopathy occurs at the very end of the tendon, where it attaches or “inserts” into the heel bone. This form can sometimes involve the development of bone spurs on the heel bone or calcification within the tendon fibers at the insertion site. Both types represent a failed healing response to repeated stress, leading to a disorganized and weakened tendon structure.
Identifying the Causes
Achilles tendinopathy develops from a combination of intrinsic and extrinsic factors. Intrinsic factors relate to an individual’s body and internal characteristics. These can include increasing age, as tendon resilience naturally decreases over time, and a person’s sex.
Biomechanical abnormalities in the foot and ankle, such as excessive pronation (flat feet), high arches, or leg length discrepancies, can alter the forces transmitted through the Achilles tendon, increasing its susceptibility to injury. Muscle weakness or imbalances in the calf muscles, particularly the gastrocnemius, can also contribute to improper loading of the tendon. Additionally, certain systemic diseases like diabetes, obesity, or other metabolic disorders can impact tendon health and increase the risk of tendinopathy.
Extrinsic factors are external influences and activities. The most common extrinsic cause is overuse or a sudden increase in physical activity, especially those involving repetitive stress on the Achilles tendon like running, jumping, or climbing. Inadequate warm-up routines before exercise or insufficient recovery time between activities can also contribute to tendon overload and microtrauma.
Improper footwear can place undue stress on the tendon. Certain medications, such as fluoroquinolone antibiotics, have also been linked to an increased risk of Achilles tendinopathy. Often, it is not a single factor but a combination of these intrinsic and extrinsic elements that leads to the development of the condition.
Recognizing Symptoms and Seeking Diagnosis
Individuals experiencing Achilles tendinopathy report pain along the Achilles tendon or at the back of the heel. This pain often feels worse during or after physical activity, particularly after periods of rest or first thing in the morning. Stiffness in the tendon and calf region is also a common complaint, especially upon waking or after prolonged sitting.
Physical examination may reveal tenderness along the affected part of the tendon, and sometimes thickening or swelling. In cases of non-insertional tendinopathy, this thickening is typically in the mid-portion, while insertional tendinopathy may show tenderness directly at the heel bone attachment. A grating noise or creaking sensation, known as crepitus, may also be felt or heard when moving the ankle.
Diagnosis begins with a clinical examination. This involves assessing the foot and ankle, including palpation of the tendon and assessing the range of motion in the ankle. The examiner may look for signs like a painful arc, where pain is present when the tendon moves through a certain range of motion.
Imaging techniques are used to confirm diagnosis and assess tendon changes. Ultrasound can visualize tendon thickening, structural disorganization, and sometimes increased vascularity. Magnetic Resonance Imaging (MRI) offers detailed images, helping to identify degenerative changes, microtears, or fatty infiltration. X-rays may be used to rule out bone spurs, especially in insertional tendinopathy, or to check for calcification within the tendon.
Treatment Approaches
Treating Achilles tendinopathy focuses on conservative management to reduce pain and restore tendon function. Initial steps involve rest and activity modification, which means reducing or temporarily stopping activities that aggravate the tendon. Applying ice packs to the affected area can help manage pain and swelling.
Physical therapy is a key part of conservative treatment, emphasizing controlled tendon loading exercises. Eccentric loading exercises, which involve lengthening the calf muscles while they are contracting, are beneficial for strengthening the tendon and promoting structural remodeling. Stretching exercises for the calf muscles and strengthening of the lower leg muscles also improve flexibility and support the tendon.
Load management, which involves gradually increasing the demands placed on the tendon as it heals, is a systematic approach. This helps the tendon adapt and regain its capacity without overloading it. Adjustments to footwear, including supportive shoes or orthotics, can help optimize foot mechanics and reduce tendon stress.
Other conservative options include shockwave therapy, which uses high-energy sound waves to stimulate healing. Certain injections, like platelet-rich plasma (PRP), may be considered in some cases, though their effectiveness can vary. Corticosteroid injections around the Achilles tendon are generally avoided due to concerns about weakening the tendon and increasing the risk of rupture.
Surgical intervention is reserved for severe, persistent cases that have not responded to a comprehensive six-month conservative treatment plan, affecting approximately 10% to 30% of patients. Surgical procedures may involve debridement, which removes damaged or degenerative tissue from the tendon, or repair of significant tears. Recovery from surgical intervention can be lengthy, and adherence to rehabilitation protocols is important for a successful outcome.