Common Injuries of the Achilles Tendon

Ankle, Common conditions, Exercise, Foot, Injury, Lifestyle, Pain

Achilles tendon injury

The thickest and the strongest tendon in our body is the tendon of the calf muscles of the leg also known as the “Achilles tendon”. 

achilles Tendon main

Fig 1: Calf muscles and Achilles tendon

As shown in Fig 1, the calf muscles of the leg include the gastrocnemius and the soleus muscles that tapers and merges with a tough connective tissue of the Achilles’ tendon. The Achilles tendon then inserts into the heel bone (calcaneus).  Functions of the Achilles Tendon

  • Downward Movement of the foot: When the calf muscles contracts and pulls the Achilles tendon it causes the foot to push downward. This contraction enables: gait, standing on the toes, running, and jumping.
  • Bending the knee: The gastrocnemius muscle helps in bending the knee (flexion) during walking and running.
  • Transferring body weight: With each step of walking each of the Achilles tendon help to distribute the person’s body weight. Depending upon the speed, stride, terrain and additional weight being carried or pushed, each Achilles tendon may be subjected to approximately 3-12 times a person’s body weight.
  • Ankle stability: Along with the other muscles of the leg the Achilles tendon contributes to the stability of the ankle joint.

What surrounds the Achilles tendon? The Achilles tendon is protected by the Achilles tendon sheath and bursae. The sheath is the covering of the tendon that protects the tendon from friction and allows smooth movements. Similarly, the bursae around the Achilles is a thin fluid-filled sac that help to reduce friction between tendon and other tissue areas of the heel.

achilles Bursas

Fig 2: Bursae around the Achilles tendon

As shown in Fig 2, there are two bursae present at the heel. One of the bursae is present in between the surface of the tendon and the surface of the calcaneus at the distal attachment of the Achilles tendon. It is called the “retrocalcaneal bursa”. The other bursa is present between the calcaneum and the skin and is called as the “subcutaneous calcaneal bursa”. 

Brief History on Achilles tendon injuries

Because of the Greek Achilles legend, the Achilles heel is known as a vulnerable part for injury. Hippocrates described that “this tendon if bruised or cut causes the most acute fevers, induces choking, deranges the mind and at length brings death”. It was first reported that a ruptured tendon was to be wrapped with bandages dipped in wine and spices. Since then the cause and treatment of Achilles tendon injuries have brought growing interests among many researchers. 

What causes an Achilles tendon injury?

  • Overuse injuries

This is mostly sports related and is due to overuse of the calf muscles causing an injury to the Achilles tendon. Overdoing or rapid action of the calf muscles or resuming too quickly after a layoff can stress the Achilles tendon. For example, while running or walking faster, up and down on steeper hills or stairs  more powerful movements such as lunges, jumps, or push off.

  • Misalignment and muscle imbalances

Short or tight Achilles tendons or calf muscles, unequal leg length, over or under arched foot, disproportionally weak calf muscles.

  • Improper Footwear 
  • Side effects of certain medications  

Medications (Quinolone / Fluoroquinolone and Cortisone) can weaken the Achilles tendon and this may lead to an injury. Cortisone shots in or near the Achilles tendon may reduce pain in the Achilles tendon, but the weakness in the tendons persists which can an injury during activities.

  • Accidental trauma
  • Inflammatory conditions

Achilles injury may occur in relation to inflammatory illnesses, such as ankylosing spondylitis, reactive arthritis, gout or rheumatoid arthritis.

  • Genetic 

Individuals with a genetic predisposition like hypermobile people are reported to be more at risk of developing Achilles tendon problems. This is because they have excessive laxity in  ankle joints that lead to the wear and tear of the Achilles tendon. 

Achilles tendon injuries

achilles tendon injury locations

Fig 3. Locations of injury

As shown in Fig 3, different types of Injuries to the tendon can occur along different locations of the tendon. 

Musculotendinous junction: This explains the junction between the calf muscle and the Achilles tendon.

Mid portion of the tendon: This explains an injury midway between the top and bottom of the Achilles tendon.

Insertional Achilles tendon injury is an injury at the bottom of the Achilles tendon, where the Achilles tendon connects with (inserts into) the heel bone.

Non-insertional Achilles tendon injury means an injury to any part of the Achilles tendon except at the Achilles tendon – heel bone connection.

Types of Achilles injuries

The spectrum of Achilles injuries ranges from an acute inflammatory irritation to severe cases of rupture of the tendon as shown in Fig 4. The types of condition may co-exist depending on the severity of the injury.

Achilles Tendon course of injury

Fig 4: Types of Achilles Tendon Injuries

Tendonitis and tenosynovitis

Achilles tendonitis is an acute inflammation of the Achilles tendon as shown in Fig 5. Tenosynovitis is an inflammatory condition of the Achilles tendon sheath, rather than an inflammation in the Achilles tendon itself.

Tendonitis insertion

Fig 5: Achilles Tendonitis

Achilles Tendinosis (Tendinopathy): This is the degeneration and micro tears of the Achilles tendon that occurs over time due to overuse of an already inflamed and weak tendon (Refer Fig 6).

Both Achilles tendonitis and tenosynovitis can occur in parallel with, or lead to Achilles tendinosis.

Print

Fig 6: Tendinosis of Achilles tendon

Tendon Ruptures (Partial or complete tendon tear) Achilles tendon rupture is often described as an abrupt break with instantaneous pain that is felt in the foot or heel area. It occurs rapidly while performing activity like running or standing on the toes, which generates intense force on the tendon, leading to partial or complete rupture as shown in Fig 7.

Rupture complete

Fig 7: Complete and partial tear of the Achilles tendon

What can happen if you have an Achilles tendon injury?

  • Pain and tenderness along the Achilles tendon and at the back of the heel that worsens with activity.
  • Thickening of the tendon
  • Bone spur formation at the insert of the tendon
  • Bruising and Swelling around the tendon area.
  • Fibrosis and scarring may be seen in Achilles Tenosynovitis and tendinosis.
  • Restriction of Achilles tendon’s motion within the Achilles tendon sheath.
  • Bursitis: Inflammation of the bursas around the Achilles tendons.
  • Snapping or popping noise can indicate a tendon rupture.
  • Difficulty in moving the foot or pointing your toes (in complete tears of the tendon)
  • A limp may be seen on weight bearing immediately after an Achilles tendon rupture
  • Ankle instability
  • Nerve or blood vessel damage: Signs include numbness, tingling, pins-and-needles sensation in your foot and bruised skin.

How is an Achilles tendon injury diagnosed? An initial examination of the ankle can help differentiate a tendon rupture from other types of injury. When an Achilles tendon rupture occurs, it will not be possible for the individual to stand on toes as shown in Fig 8.

achilles tendon rupture and normal

Fig 8: Achilles tendon rupture of the Left heel

 An MRI or X-ray investigation can also be taken to further confirm the severity of the injury and differentiate the type of injury to the tendon. For example, an MRI scan of a ruptured Achilles tendon is shown in Fig 9.

Complete tear MRI

Fig 9: Achilles tendon rupture

When to seek expert care?

If you felt a sharp pain like a direct hit to the Achilles tendon or if you heard a distinct snap at your Achilles tendon, it calls for a medical emergency. If you have just begun with pain in the back of heels with swelling or discomfort in the Achilles tendon, it would be wise to seek expert assessment and treatment care. What may seem like a mild inflammation may lead to degeneration and rupture. Thus, an initial treatment for tendonitis will not only reduce problems of the tendon but will restore its strength and function which is important to prevent worsening and recurrence of the condition.  

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Ankle 101

anatomy, Ankle, Foot

ankle joint only

The ankle plays an important role in the pattern of lower limb movements both in weight-bearing and non-weight-bearing positions.

Ankle movements: (Refer Fig 1)

  • Plantarflexion (down)
  • Dorsiflexion(up)
  • Inversion (inwards)
  • Eversion (outwards)
dorsi and plantar flexion

Fig 1: Dorsiflexion, Plantarflexion, Eversion and Inversion

Plantar flexion is the movement that describes the pointing of the toes toward the ground, as in standing on one’s toes.

Dorsiflexion is the opposite of plantarflexion and involves pulling the toes up as in walking on one’s heels.

Inversion is inward rolling of the foot towards the body’s midline and eversion is the exact opposite which involves outward rolling of the foot away from the midline of the body.

Joints in relation to movement

The ankle is made up of three distinct joints namely, 

  • Talo-crural joint (Ankle joint)
  • Subtalar joint 
  • Distal Tibiofibular joint (High ankle)
joints of the ankle

Fig 2: 3 types of ankle joints

Talo-crural joint (Ankle joint): It a hinge type of joint that allows movements of dorsiflexion and plantar flexion along one plane.The articulation of the lower ends of the leg bones and one of the tarsal bones (talus) forms the ankle joint.  

Subtalar joint: The movements of Inversion and eversion take place at this joint. It lies beneath the ankle joint and is formed by the articulation between the talus and the calcaneal bone of the foot. 

Distal tibiofibular joint (High ankle): This is a syndesmosis joint between the lower ends of the bones of the leg(tibia and fibula).  A syndesmosis joint is a joint where the bones are connected by ligaments and have minimal movements.

Muscles that cause ankle movements

The muscles from the leg end as tendons that attach to the foot bones. They contract and transfer forces to cause a movement across the ankle joint.

  • Outer muscles of the leg: The peroneal (Peroneus long and peroneus brevis) muscles are present on the outside aspect of the leg as shown in Fig 3. The contraction of the peroneal muscles help bend the ankle down moving the foot downwards (Plantar flexion) as in fig 3.
Peroneal muscles

Fig 3: Peroneal Muscles and Plantar flexion

The peroneals also help to stabilize the big toe as it attaches behind it. It helps to lift the arch and plantar fascia to produce spring-like effect during running and jumping activities.

  • Back muscles of the leg: The calf muscles (gastrocnemius and soleus) and the tibialis posterior muscles are present at the back of the leg as shown in Fig 4.
back of the leg

Fig 4: Calf and Tibialis posterior muscle.

The calf connects to the heel bone by the Achilles’ tendon. When the calf muscles contract they moving the foot downwards (Plantar Flexion). The posterior tibialis help to turn the foot inwards (Inversion). They help to propel the body forwards as the foot pushes on the ground while walking.

  • Front muscles of the leg: The tibialis anterior present in the front of the leg  and attached in the front of the foot as shown in Fig 5.
tibialis anterior muscle

Fig 5: Tibialis anterior muscle and dorsiflexion

The Tibialis anterior muscle pulls the ankle upwards (Dorsiflexion). It plays a role in striking the heel when you take a step forwards in walking.

Ligaments that support the ankle

Apart from muscles, the ankle is stabilized by many ligaments that surround the ankle. 

  • Lateral ligaments (outer ankle ligaments)
  • Medial ligaments (inner ankle ligaments)
  • High ankle ligaments

Lateral ligaments

Lateral ligaments are present on the outer aspect of the ankle that are attached at the anterior (front), lateral (outer side) and posterior (back) parts of the ankle as shown in Fig 6. 

Outer ligaments of the ankle

Fig 6: Lateral Ligaments

  • The Lateral ligaments play an important role to prevent excessive plantar flexion and inversion movements of the foot. 
  • Along with the medial ligaments, they also provide stability to the ankle during weight bearing movements.

Medial ligaments (Inner Ankle Ligaments) 

The medial ligament otherwise known as deltoid ligament is present on the inner aspect of the ankle, as shown in Fig 7. 

Ligaments of the ankle

Fig 7: Medial ligaments (Deltiod ligament)

  • The medial ligaments function as the main stabilizer of the inner aspect of the ankle against shear and rotational forces.
  • They also act to support the inner arch of the foot.

Distal tibiofibular ligaments

The distal tibiofibular ligaments are located above the ankle and connect the high ankle syndesmosis joint as shown in Fig. 8. 

Syndesmotic ligament complex

Fig 8. High ankle ligaments

  • The high ankle ligaments ensure stability between the lower end of the tibia and the fibula.
  • They resist any force that attempt to separate the tibia and fibula.

Risk of injury to the ankle 

Any inflexibility in the ankle may cause inability to perform a movement properly. For example, poor ankle mobility due to tight soft tissue structures can reduce the range of movement at the ankle causing the knees, hips and trunk to over compensate. This may impair the ability of the trunk to load the joints properly hence increasing the risk an injury.