Orthopaedic Surgery - Achilles Tendon Rupture

Basics

The Achilles tendon is the strongest tendon in the human body and is capable of withstanding forces of approximately 5–7 times body weight during activity. Achilles tendon rupture refers to disruption of the tendon, most commonly occurring within its relatively poorly vascularized watershed region.

The Achilles tendon represents the terminal confluence of the medial and lateral heads of the gastrocnemius together with the soleus muscle. It measures approximately 15 cm in length and inserts onto the posterior calcaneal tuberosity.

The tendon is surrounded by a paratenon, which allows smooth gliding movement relative to the surrounding tissues. Histologically, it is composed predominantly of type I collagen.

The poorest blood supply is found approximately 2–6 cm proximal to the calcaneal insertion, creating a watershed region that is particularly susceptible to degeneration and rupture. As the tendon travels distally, it undergoes approximately 90° of rotation, which further concentrates mechanical stress within this vulnerable region.

Achilles tendon ruptures may be classified as acute or chronic, open or closed, and complete or incomplete.

General Prevention

Regular conditioning, progressive training, and appropriate stretching may promote adaptation of the Achilles tendon. Repeated loading produces structural adaptation, including an increase in tendon cross-sectional area.

Gradual increases in physical activity are preferable to sudden changes in exercise intensity, particularly in individuals who participate in vigorous sport intermittently.

Epidemiology

Achilles tendon rupture demonstrates a bimodal age distribution.

The first major group consists of young to middle-aged athletes, commonly between 30 and 40 years of age. Approximately 60–75% of ruptures in this group occur during sporting activity.

The particular sport responsible varies between countries and regions depending on local patterns of participation.

A second group consists of older, relatively inactive individuals. A smaller proportion of ruptures, approximately 13%, occur in older nonathletic patients.

Incidence

The precise incidence varies considerably among published studies, with estimates ranging from approximately 2 to 37.3 cases per 100,000 population.

The incidence of Achilles tendon rupture has increased over recent decades, possibly reflecting greater participation in recreational sport and physical activity among middle-aged adults.

Prevalence

Achilles tendon rupture predominantly affects males.

The left Achilles tendon has been reported to rupture more frequently than the right. One proposed explanation is that many right-hand-dominant athletes preferentially use the left leg as the push-off limb during sporting activity.

The condition is more frequently reported in industrialized countries and is especially associated with so-called weekend warriors, who participate in vigorous sporting activity intermittently without consistent conditioning.

Risk Factors

A previous Achilles tendon rupture increases the risk of rupture of the opposite tendon. In some studies, subsequent contralateral rupture has occurred in up to approximately 6% of patients.

Several medications are associated with an increased risk of tendon degeneration and rupture. These include systemic corticosteroids, local corticosteroid injections around the Achilles tendon, anabolic steroids, and fluoroquinolone antibiotics.

A number of systemic diseases have also been associated with spontaneous Achilles tendon rupture, although these account for a relatively small proportion of cases. Important examples include diabetes mellitus, rheumatoid arthritis, other inflammatory arthritides, and gout.

Pathophysiology

Histological examination of ruptured Achilles tendons commonly demonstrates underlying chronic degenerative abnormalities.

Features of tendinosis, including collagen disorganization, mucoid degeneration, and deterioration of the normal tendon architecture, are frequently present even when the patient did not have significant symptoms before rupture.

This suggests that an apparently sudden rupture often represents an acute mechanical failure of a tendon that has already undergone chronic structural degeneration.

Etiology

The most common mechanism is an indirect injury rather than direct trauma.

A typical rupture occurs when the patient forcefully pushes off from a weight-bearing foot while simultaneously extending the knee. This produces a sudden and substantial load across the Achilles tendon.

Another common mechanism involves forceful eccentric contraction of the gastrocnemius–soleus complex, in which the muscle contracts while the tendon is being lengthened.

Direct trauma is much less common. Penetrating injuries such as a laceration or gunshot wound may directly divide the Achilles tendon.

Associated Conditions

Achilles tendon rupture may occur in association with pre-existing Achilles tendinopathy.

Insertional disorders may include retrocalcaneal bursitis and insertional Achilles tendinopathy, whereas noninsertional pathology may include tendinosis and peritendinitis.

Diagnosis

Signs and Symptoms

Patients commonly report a sudden snap or pop in the posterior ankle at the time of injury.

A characteristic description is the sensation of having been struck, kicked, or hit in the back of the lower leg despite no external contact occurring.

Pain may initially be severe. Localized swelling, tenderness, and a palpable defect along the Achilles tendon, together with weakness of active plantarflexion, strongly suggest rupture.

History

A complete foot and ankle history should be obtained, including the exact mechanism of injury and the patient’s activity level.

The clinician should specifically ask about previous episodes of Achilles pain, stiffness, swelling, or symptoms suggestive of chronic tendinopathy, because degenerative changes frequently precede rupture.

Medication history and relevant systemic disorders should also be reviewed.

Physical Examination

A general examination of the foot and ankle should be performed, with particular attention to the posterior ankle.

The Achilles tendon should be inspected and palpated for tenderness, swelling, bruising, and a palpable gap in the tendon.

Plantarflexion strength should be assessed carefully. A patient with a complete Achilles rupture may still be able to plantarflex the ankle because other muscles can assist with the movement. However, plantarflexion will usually be substantially weaker than on the unaffected side.

The patient will generally be unable to perform a single-leg heel rise on the injured side.

Knee Flexion Test

The patient is positioned prone with both knees flexed to approximately 90°.

The resting position of the affected ankle is compared with that of the normal side. An intact Achilles tendon maintains resting tension within the gastrocnemius–soleus complex and therefore holds the ankle in slight plantarflexion.

When the Achilles tendon is ruptured, this normal resting tension is lost, and the affected ankle assumes a relatively more dorsiflexed position compared with the opposite side.

Thompson Test

The Thompson test is an important clinical test for Achilles tendon rupture.

The patient is placed prone with the feet extending beyond the examination table. The examiner compresses the calf musculature.

With an intact Achilles tendon, compression of the gastrocnemius–soleus complex produces passive plantarflexion of the ankle.

If the Achilles tendon is completely disrupted, calf compression fails to produce normal passive plantarflexion, strongly indicating loss of tendon continuity.

Laboratory Tests

Routine laboratory investigations are generally unnecessary for diagnosing an acute Achilles tendon rupture.

Preoperative laboratory tests are obtained when surgical treatment is planned and should be selected according to the patient’s age, medical history, and perioperative requirements.

Imaging

Plain Radiographs

Plain radiographs may be obtained to evaluate the osseous structures of the ankle and hindfoot.

Although radiographs do not directly demonstrate most Achilles tendon ruptures, they are useful for excluding associated fractures and other bony abnormalities.

If radiographs suggest an avulsion fracture involving the calcaneal tuberosity together with the Achilles tendon insertion, computed tomography (CT) may be useful for defining the fracture pattern and assisting surgical planning.

MRI and Ultrasound

Most acute Achilles tendon ruptures can be diagnosed clinically without advanced imaging.

When the diagnosis remains uncertain, MRI can demonstrate the location and extent of the rupture, the degree of tendon retraction, and the condition of the surrounding tissues.

Ultrasound may also be used to confirm tendon discontinuity or partial tearing. It can be particularly useful as a rapid, dynamic imaging technique when appropriate expertise is available.

Differential Diagnosis

Important differential diagnoses include Achilles tendinopathy, partial Achilles tendon rupture, and calcaneal fracture.

Partial tears may be more difficult to recognize clinically because some tendon continuity and plantarflexion function are preserved.

Initial Stabilization

Once an Achilles tendon rupture has been diagnosed, the ankle should be immobilized promptly.

A well-padded below-knee splint is applied with the ankle maintained in equinus or plantarflexion. This position brings the torn tendon ends closer together and reduces tension across the rupture site.

Initially, the patient is generally kept non-weight-bearing. Ice application and elevation are useful for reducing swelling and discomfort.

General Treatment Principles

Management may be either operative or nonoperative.

The choice depends on several factors, including the patient’s age, general medical health, functional demands, sporting activity, rupture characteristics, and personal preferences.

Historically, surgical treatment has often been favored for younger, healthy, highly active patients. However, contemporary functional rehabilitation protocols have improved outcomes following nonoperative treatment.

Both surgical and nonsurgical approaches have specific advantages and complications, and the treatment decision should therefore be individualized.

Nonoperative Management

Traditional nonoperative treatment involves immobilization of the lower leg in a below-knee cast with the ankle initially positioned in full equinus.

Over approximately 6–10 weeks, the ankle is gradually brought toward a neutral or plantigrade position. This may be achieved by serial cast changes, commonly at intervals of approximately two weeks.

Weight-bearing is usually introduced after approximately 4–6 weeks, depending on the rehabilitation protocol and clinical progress.

After the immobilization period, a heel lift may be used for several months to decrease tension on the healing Achilles tendon.

Functional Bracing

Modern nonoperative protocols increasingly use a removable boot or functional brace rather than prolonged rigid casting.

The brace initially restricts ankle dorsiflexion while allowing a degree of plantarflexion.

As healing progresses, the dorsiflexion restriction is gradually reduced, permitting increasing ankle motion and progressive loading of the tendon.

Functional bracing allows rehabilitation to begin earlier while maintaining the tendon in a protected position.

Activity

With traditional nonoperative management, full weight-bearing is usually avoided during the first 4–6 weeks.

More modern functional rehabilitation protocols may permit earlier protected weight-bearing, depending on tendon position, patient factors, and the treating surgeon’s protocol.

Return to unrestricted activity should be gradual and guided by restoration of tendon strength, ankle motion, balance, and functional performance.

Physical Therapy

A variety of rehabilitation protocols are available after both operative and nonoperative treatment.

Early rehabilitation generally begins with controlled active ankle motion within a protected range.

As tendon healing progresses, therapy advances to progressive weight-bearing, strengthening, balance training, and restoration of calf endurance.

Later stages focus on functional exercises and gradual return to running, jumping, and sport-specific activity.

Surgical Management

Open Repair

Open surgical repair is one established treatment option for an acute Achilles tendon rupture.

Surgery may be delayed briefly, often for approximately one week, to allow acute swelling to decrease.

The patient is generally positioned prone. Both lower extremities may be included in the operative field so that the resting position and tension of the repaired ankle can be compared with those of the normal side.

A longitudinal medial incision adjacent to the Achilles tendon is commonly used because this approach helps reduce the risk of injury to the sural nerve.

Tendon Repair Technique

Strong sutures are placed into the proximal and distal tendon segments and tied with the tendon ends appropriately opposed.

Locking suture configurations with multiple strands passing through each tendon segment can provide substantial repair strength.

The paratenon should be preserved whenever possible and repaired at the conclusion of the procedure. Restoration of the paratenon may improve tendon gliding and reduce postoperative adhesions.

When present and suitable, the plantaris tendon may be opened and wrapped around the Achilles repair as an additional biological layer and to potentially reduce adhesion formation.

Percutaneous Repair

Several minimally invasive and percutaneous Achilles tendon repair techniques have been developed.

These procedures use multiple small stab incisions and specialized instruments to approximate and suture the ruptured tendon ends.

Potential advantages include smaller incisions, reduced soft-tissue disruption, and a lower risk of wound complications compared with traditional open surgery.

However, percutaneous techniques may carry a greater risk of injury to the sural nerve, depending on the technique used.

Surgical Management of Chronic Ruptures

Chronic Achilles tendon ruptures are technically more difficult to repair because the tendon ends may retract and scar, and the gastrocnemius–soleus complex may become shortened or atrophic.

Treatment depends largely on the size of the tendon defect and the quality of the remaining tissue.

When direct end-to-end repair is possible, the tendon ends may be mobilized and repaired primarily.

If a large gap prevents direct repair, reconstructive options include V–Y advancement or lengthening, turndown tendon flaps, tendon transfers, tendon augmentation, and allograft reconstruction.

Tendon Transfer and Augmentation

When substantial tissue loss or chronic degeneration is present, local tendon transfer may be required.

The flexor hallucis longus (FHL) is commonly used because of its anatomical proximity, strength, and similar direction of pull.

The flexor digitorum longus may also be used in selected cases.

Large chronic defects may occasionally require an allograft tendon or other reconstructive techniques to restore continuity between the gastrocnemius–soleus complex and calcaneus.

Follow-Up

Both operative and nonoperative treatment can provide good functional outcomes when accompanied by appropriate rehabilitation.

Follow-up should assess tendon healing, ankle motion, calf strength, gait, heel-rise ability, swelling, and functional recovery.

Progression of activity should be gradual to avoid excessive loading of the healing tendon.

Prognosis

The overall prognosis after Achilles tendon rupture is generally favorable with either operative or appropriately structured nonoperative treatment.

Clinical trials have demonstrated that both approaches can result in comparable return to sports, strength, endurance, and ankle range of motion when effective rehabilitation protocols are used.

A substantial proportion of patients treated by either method regain normal or near-normal function, although residual calf weakness or reduced endurance may persist in some individuals.

Complications of Surgical Treatment

Potential complications following surgical repair include adhesions, altered sensation, sural nerve symptoms, wound infection, wound dehiscence, and rerupture.

Reported surgical complication rates vary according to surgical technique and patient characteristics.

Wound complications are particularly important because the posterior ankle has relatively limited soft-tissue coverage and can be vulnerable to delayed healing.

Complications of Nonoperative Treatment

The major concern following nonsurgical treatment is rerupture, particularly when prolonged immobilization protocols are used without early functional rehabilitation.

Other potential complications include adhesions, excessive tendon lengthening, persistent weakness, and reduced push-off strength.

Excessive healing in an elongated position can impair calf function even when the tendon remains intact.

Deep Vein Thrombosis

Deep vein thrombosis (DVT) is an important complication following Achilles tendon rupture and can occur after either operative or nonoperative treatment.

The combination of lower-limb injury, immobilization, and reduced weight-bearing contributes to venous stasis.

Patients should therefore undergo individualized assessment for venous thromboembolism risk, and thromboprophylaxis should be considered when clinically appropriate.

Open Versus Percutaneous Repair

Compared with traditional open repair, percutaneous surgery may offer a shorter operative time and a lower incidence of wound infection.

However, some studies have reported higher rates of rerupture and sural nerve injury with percutaneous techniques.

Modern minimally invasive approaches and improved instrumentation may reduce these complications, and outcomes continue to evolve with newer techniques.

Patient Monitoring

Following surgical repair, sutures are commonly removed at approximately 2 weeks, provided that wound healing is satisfactory.

Immobilization or functional bracing is continued according to the selected postoperative protocol, followed by progressive ankle motion, weight-bearing, and strengthening.

Patients should be monitored for wound problems, infection, rerupture, tendon elongation, sural nerve symptoms, calf weakness, and signs of venous thromboembolism.

Appropriate DVT prophylaxis should be considered according to the patient’s individual risk factors and treatment protocol.