Achilles tendon injury


Most Achilles tendon problems are related to overuse injuries and are multifactorial. The principal factors include host susceptibility and mechanical overload.

Incidence

Although the worldwide frequency of Achilles tendon ruptures is not known, data collected from Finland estimates that it occurs in 18 per 100,000 people yearly. The male-to-female ratio of rupture is estimated from 1.7:1 to 12:1.

Causes

The common precipitating event that causes an Achilles tendon rupture is a sudden, eccentric force applied to a dorsiflexed foot. Ruptures of the Achilles tendon also may occur as the result of direct trauma or as the end result following Achilles peritenonitis, with or without tendinosis. Risk factors associated with Achilles tendon rupture include the following:

Clinical Examination

With either partial or complete Achilles tendon rupture, patients typically experience sharp pain, often described as feeling like being kicked in the leg.

The physical examination reveals a localized, tender area of swelling that may involve some intratendinous nodularity. With complete rupture, the examination normally reveals a palpable depression on the tendon. In this setting, the Thompson test is generally positive (i.e., squeezing the calf does not cause active plantar flexion), and the patient usually is incapable of performing a single heel-raise

The Thompson test can be falsely positive when the accessory ankle flexors (posterior tibialis, flexor digitorum longus, flexor hallucis longus muscles, or accessory soleus muscles) are squeezed together with the contents of the superficial posterior leg compartment. Delayed or missed diagnosis of Achilles tendon ruptures by primary treating physicians is relatively common. In a study by Inglis and Sculco 38 of 167 (23%) Achilles tendon ruptures were initially misdiagnosed by the primary treating physician.

 Investigation

Radiographs are more useful in ruling out other injuries than in ruling in Achilles tendon ruptures

Ultrasonography can be used to determine the tendon thickness, character, and presence of a tear.

Magnetic resonance imaging (MRI) can be used to discern incomplete ruptures from degeneration of the Achilles tendon, and MRI can also distinguish between paratenonitis, tendinosis, and bursitis.

Treatment

The treatment goals of a ruptured Achilles tendon are to restore normal musculotendinous length and tension and thereby to optimize ultimate strength and function of the gastrocnemius-soleus complex. Whether operative or nonoperative treatment best achieves these goals remains a matter of controversy. Proponents of surgical repair point to lower recurrent rupture rates, improved strength, and a higher percentage of patients who return to sports activities

Non-operative

Clinicians favoring nonoperative treatment stress the high surgical complication rates resulting from wound infection, skin necrosis, and nerve injuries. With careful operative technique, and use of newer guide systems, these complications can be minimized, but not eliminated.

Operative

Surgical treatment is often preferred when treating younger and more athletic patients. Several different operative techniques have been described, including percutaneous and open approaches. Percutaneous approaches have the advantage of decreased dissection but have historically carried the disadvantages of potential entrapment of the sural nerve.

Torn Achilles tendon.

Torn Achilles tendon.

 

Conservative versus surgical complication rates

According to Kahn et al, there was a consistent finding of an approximately 33% higher rate of complications (other than rerupture) in those treated surgicall ; nonoperatively treated patients had a rerupture rate approximately 3 times higher than those treated surgically, but these patients had minimal risk for other complications. Listed complications resulting from open surgical repair included deep infections (1%), fistulae (3%), necrosis of the skin or tendon (2%), rerupture (2%), and minor complications (percentage not documented).

Long term outcome

isokinetic studies demonstrated a loss of static and dynamic strength in plantar flexion of the ankle joint of 9.1%, and 16.7% respectively, when compared to the healthy contralateral side. The ultrasound examination revealed a thickening of the tendon and of the dorsal paratenon with changes in the internal structure of the injured Achilles tendon.