Percutaneous Achilles Tendon Repair Perspective 2

Rupture of the Achilles tendon is common.

More than 20% of acute injuries are misdiagnosed, leading to chronic or neglected ruptures.⁷

ANATOMY

The two heads of the gastrocnemius arise from the condyles of the femur, the fleshy part of the muscle extending to about the midcalf. As the muscle fibers descend, they insert into a broad aponeurosis that contracts and receives the tendon of the soleus on its deep surface to form the Achilles tendon.¹¹

The Achilles tendon is the thickest and strongest tendon in the body. About 15 cm long, it originates in the midcalf and extends distally to insert into the posterior surface of the calcaneus. It receives muscle fibers from the soleus on its anterior surface throughout its length.¹¹

PATHOGENESIS

The most common mechanism of injury is pushing off with the weight-bearing forefoot while extending the knee. Sudden unexpected dorsiflexion of the ankle or violent dorsiflexion of a plantarflexed foot may also result in ruptures.⁸

Corticosteroids, fluoroquinolone use, tendon pathology, and poor vascularity of the Achilles tendon have been associated with rupture.⁸

NATURAL HISTORY

A delay in treatment of Achilles tendon rupture results in the formation of a discrete gap. The gap between ruptured tendon ends may fill with fibrous nonfunctional scar. Patients find walking and ascending stairs difficult and standing on tiptoes on the affected limb impossible.

PATIENT HISTORY AND PHYSICAL FINDINGS

Patients often give a history of feeling a blow to the posterior aspect of the leg and may describe an audible snap followed by pain and inability to bear weight.

In acute tendon ruptures, a gap in the Achilles tendon is usually palpable. In delayed presentation, edema may fill this gap, making palpation unreliable.

Active plantarflexion of the foot is usually preserved due to the action of the tibialis posterior and the long toe flexors.

The calf squeeze test, first described by Simmonds¹⁰ in 1957 but often credited to Thompson, is performed with the patient prone and the ankles clear of the table. The examiner squeezes the fleshy part of the calf, causing deformation of the soleus and resulting in plantarflexion of the foot if the Achilles tendon is intact. The affected leg should be compared to the contralateral leg.

The knee flexion test is performed with the patient prone and the ankles clear of the table. The patient is asked to actively flex the knee to 90 degrees. During this movement, the foot on the affected side falls into neutral or dorsiflexion and a rupture of the Achilles tendon can be diagnosed.⁹

IMAGING AND OTHER DIAGNOSTIC STUDIES

The diagnosis of acute ruptures is usually a clinical one.

Plain lateral radiographs may reveal an irregular configuration of the fat-filled triangular space anterior to the Achilles tendon and between the posterior aspect of the tibia and the superior aspect of the calcaneus.

DIFFERENTIAL DIAGNOSIS

Ankle sprain

NONOPERATIVE MANAGEMENT

Acute ruptures may be managed conservatively in an equinus cast for 6 to 8 weeks before being converted to a functional brace.

Conservative management may result in tendon lengthening, thus altering function.¹

SURGICAL MANAGEMENT

Percutaneous repair⁶ was originally described as a compromise between open surgery and conservative management. A percutaneous repair aims to provide the optimal functional outcome of open repair while decreasing the problems associated with it in terms of wound healing and skin breakdown. Recent studies suggest that minimally invasive surgery is less expensive, less time demanding, and it has similar outcome compare to open repair in surgical management of acute Achilles tendon rupture.^2,3 However, iatrogenic neurologic complications, such as sural nerve injury, are more frequent after percutaneous repair.

Preoperative Planning

Once the diagnosis is made, an assessment of general health and comorbidities should be performed.

The preoperative functional status should be noted.

The skin quality and neurovascular status of the affected limb should be examined.

The status of the sural nerve should be documented.

We recommend that the patient be maintained on deep venous thrombosis prophylaxis.

The procedure can be performed under general anesthesia or a local anesthetic, with a 50:50 mixture of 10 mL of 2% lignocaine hydrochloride (Antigen Pharmaceuticals Ltd, Roscrea, Ireland) and 10 mL of 0.25% bupivacaine hydrochloride (Astra Pharmaceuticals Ltd, Kings Langley, England) instilled into an area of between 8 and 10 cm around the ruptured Achilles tendon.

Positioning

The patient is placed prone and a pillow is placed beneath the anterior aspect of the ankles to allow the feet to hang free.

The operating table is angled down 20 degrees cranially to reduce venous pooling in the feet and ankles.

The affected leg is prepared with antiseptic and sterile draped. We do not use a tourniquet.

Local anesthetic infiltration is used. Instill a 50:50 mixture of 10 mL of 2% lignocaine hydrochloride (Antigen Pharmaceuticals) and 10 mL of 0.25% bupivacaine hydrochloride (Astra Pharmaceuticals) into an area 8 to 10 cm around the ruptured Achilles tendon.

Approach

Previous approaches such as those described by Ma and Griffith⁶ using three medial and three lateral stab incisions have been abandoned in light of the relatively increased incidence of sural nerve entrapment.