Introduction

Achilles tendinitis is an injury to the tendon that connects the muscles in the lower leg to the heel bone. A tendon is made up of tough tissue known as connective tissue, all tendons connect muscle to bone. The main function of a tendon is to transmit the force generated by the muscle to the bone, allowing movement to occur at a joint.

Tendons also provide stability at joints, absorb shock and distribute the forces generated during movement, which helps to protect the bones and joints from damage. Achilles tendonitis occurs when the Achilles tendon becomes swollen, which often can be easily managed at home. However, in some cases, it may lead to serious complications such as tendon rupture.

In older adults’ tendons, are less flexible, and there is an increased susceptibility to injury and inflammation. It is therefore even more important that older individuals take the correct preventive measures and management strategies. This article will discuss in more detail the symptoms, development and signs of Achilles tendinitis, including the appropriate preventative measures and treatment strategies available.^1,2

Structure of the calf and achilles tendon

Two main primary muscles make up the calf: the gastrocnemius, which is the larger and more superficial of the two, and the soleus muscle, which is located underneath the gastrocnemius and originates from the tibia and fibula bones of the lower leg. Both of these muscles converge to form the Achilles tendon, which attaches to the heel bone (known scientifically as the calcaneus).

These muscles and the Achilles tendon work together to provide propulsion and support during movement. A tendon is typically described as dense and tough, much like a thick cord or rope. It may have some degree of elasticity, allowing it to stretch slightly under tension, but it is not as pliable as muscle tissue.³

Although the Achilles tendon is the largest and strongest tendon in the body, it is still much more susceptible to tendonitis compared to other tendons for many reasons:

• High stress and load-bearing tendon - during walking, running and jumping a significant force is generated from the calf muscles. This force is transmitted to the heel bone through this tendon and this puts it under significant stress
• Limited blood supply- an inadequate blood supply can impair a tendon's ability to repair after injury, making chronic and long-term inflammation likely
• The structure of the calf- due to the movement of the calf muscles, the Achilles tendon also experiences significant amounts of compression and tension. It is not only responsible for force transmission but also ankle stability and shock absorption

Risk factors for achilles tendonitis

There are a variety of risk factors and causes that can contribute to Achilles tendonitis:

• Overuse & repetitive strain – The most common cause of Achilles tendon injuries is overuse and repetitive strain without allowing sufficient time for recovery. This is common in sports that involve running and or changes of direction, such as basketball, athletics and football. Pain can commonly arise after a sudden increase in volume or intensity without adequate strength training
• Calf tightness – Tightness in either calf muscle can put extra strain on the Achilles tendon, exacerbating inflammation and pain. Older individuals tend to have decreased flexibility which can worsen the problem
• Foot structure and muscle mobility- unusual foot structure or running styles can alter the distribution of forces along the calve, increasing the stress on the Achilles tendon and predisposing it to injury^4,5

Many of these risk factors can be addressed by correcting form, carrying out the appropriate strength training and gradually increasing the intensity and progression of the exercise or sport. 

Risk factors for achilles tendinitis in older adults

For older adults it can be more difficult as ageing is known to reduce the capacity of tissues to regrow and increase the susceptibility to tendon injuries, making Achilles tendinitis significantly more common in middle and older-aged adults. 

Older Individuals are also more likely to develop chronic conditions such as arthritis or diabetes, the latter of which can reduce blood flow circulation and exacerbate pre-existing tendonitis. 

A further exacerbating factor in older individuals is a reduction in levels of activity. This can contribute to tendinitis through a variety of mechanisms:

• Decreased muscle mass - caused by a lack of physical activity, which can increase the strain on the Achilles tendon
• Reduced tissue resilience – without regular exercise the integrity of the tendons can’t be maintained, making them vulnerable to injury
• Joint stiffness - lack of movement and activity can lead to joint stiffness and reduced range of motion. This can alter the mobility of muscles, leading to the aforementioned increased risk of injury
• Weight gain, as a result of lack of activity, can put extra strain and pressure on the muscles and the tendon¹

Symptoms and diagnosis

It is important to recognize the signs of Achilles tendonitis so that appropriate action can be taken. It typically begins as a dull ache after activity. Common symptoms include:

• Pain and stiffness along the entire tendon
• Swelling or warmth along the tendon
• Pain and stiffness in the morning
• Feeling a grating or crackling sensation when moving the tendon
• Swelling that gets worse with activity
• Difficulty standing up on one toe^1,2

A doctor will typically take a history and examination, including questions about the level of activity you undertake. They will also examine the range of motion of the ankle joints, as well as any positions that cause pain. 

They may refer to a physiotherapist for varying strength and stretching exercises, as well as prescribe anti-inflammatory drugs. If the pain persists you may be referred to a doctor who specialises in muscles and bones (orthopaedic specialist). The doctor may offer steroidal injections for temporary pain relief and even surgery to remove damaged tissue. 

Often multiple imaging tests will be carried out to check the extent of the injury: 

• X-ray test may be conducted to rule out arthritis and fractures
• Ultrasound can be used to show tendon inflammation 
• MRI scans can be used to show the extent of tendon damage by providing detailed imaging of the tissue

Management approaches

A common recommendation by many doctors for a variety of injuries is ‘RICE’. This also applies to Achilles tendonitis. 

The “RICE” method recommends the following: 

• Rest- complete rest or switch to exercise that is less intense on the tendon e.g Cross training instead of running
• Ice- Icing the tendon for 10-20 minutes throughout the day
• Compression - using athletic tape or surgical tape to apply compression to the tendon 
• Elevate - lying down and raising/elevating the foot above the body to reduce swelling

Another easy thing to do is to protect the tendon by avoiding steep inclines and overstretching it. As mentioned, there are over-the-counter pain drugs available, as well as topical drugs such as creams that can be directly applied to the skin.

If the problem persists and the pain can’t be relieved through these conservative treatment options, there are further treatments available:

Extracorporeal shock wave therapy (ESWT)

A device that is used that delivers sound waves to the affected area to promote healing and reduce pain. This is thought to promote tissue renewal, improve blood flow, and decrease inflammation(swelling), however, the exact mechanism of action is not fully understood. You may require multiple sessions of treatment.

Platelet-rich plasma (PRP) injections

PRP therapy involves injecting a concentrated solution of platelets (a type of cell involved in wound healing) from the patient's blood into the affected area of the Achilles tendon, to stimulate tendon regeneration and repair.

Surgery

As a last resort surgery may be carried out. This can be to remove the damaged tissue, transfer a part of a tendon from another part of the body to the Achilles or lengthen the tendon to release tension and reduce pain.

To reiterate the point, these treatment options are only provided in severe cases of tendonitis that don’t respond well to the above conservative methods. In these cases, there is often serious difficulty walking, severe pain and tendon degeneration.^1,2

Summary

Achilles tendonitis is a condition involving inflammation of the tendon connecting the calf muscles to the heel bone. Ageing increases the chance of developing tendonitis due to a variety of causes, but particularly due to decreased flexibility and tissue regeneration.

Common causes of tendonitis include overuse, calf tightness, and even abnormal foot structure. Symptoms include pain, stiffness, and swelling along the tendon. Diagnosis involves physical examination and imaging tests. Management includes the RICE method (Rest, Ice, Compression, Elevation), anti-inflammatory drugs, and topical creams.

In severe cases, treatments like extracorporeal shock wave therapy, platelet-rich plasma injections, or surgery may be necessary. Overall, preventive measures and appropriate management are essential, especially for older individuals, to alleviate symptoms and prevent complications