Chronic Achilles Tendon Ruptures Using Hamstring/Peroneal Tendons

Rupture of the Achilles tendon is common.

More than 20% of acute injuries are misdiagnosed, leading to chronic or neglected ruptures.⁴

Most authors define chronic rupture as a rupture with a delay in diagnosis or treatment for more than 4 weeks.^3,12,13

ANATOMY

The two heads of the gastrocnemius (medial and lateral) arise from the condyles of the femur, the fleshy part of the muscle extending to about the middle of the calf. As the muscle fibers descend, they insert into a broad aponeurosis, which contracts and receives the tendon of the soleus on its deep surface to form the Achilles tendon.

The Achilles tendon is the thickest and strongest tendon in the body. About 15 cm long, it originates in the middle of the calf and extends distally to insert into the posterior surface of the calcaneum. Throughout its length, it receives muscle fibers from the soleus on its anterior surface.

PATHOGENESIS

The most common mechanism of injury is pushing off with the weight-bearing forefoot while extending the knee. However, sudden unexpected dorsiflexion of the ankle or violent dorsiflexion of a plantarflexed foot may also result in ruptures.⁵

Corticosteroids, fluoroquinolones, previous tendon pathology, and poor vascularity of the Achilles tendon have been associated with rupture.⁵

Patients with chronic ruptures of the Achilles tendon recall either minimal trauma or an injury misdiagnosed as an ankle sprain. They commonly complain of a limp and difficulties with activities of daily living, particularly ascending stairs.⁷

PATIENT HISTORY AND PHYSICAL FINDINGS

Methods for examination include the following:

Palpable gap. Gap is not always palpable in chronic ruptures.

Calf squeeze test (Simmonds test or Thompson test)¹⁶: positive or negative. False positive may be possible if plantaris is present and intact.

Knee flexion test (Matles test)¹⁰: A false positive may occur when there is neurologic weakness of the Achilles tendon.

Patients may present with a limp.

In acute tendon ruptures, a gap in the Achilles tendon is usually palpable. This gap may be absent in chronic ruptures, as the gap is usually bridged by scar tissue.

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

The calf squeeze test, first described by Simmonds in 1957,¹⁶ but often credited to Thompson, who redescribed it in 1962, is performed with the patient prone and ankles clear of the couch. The examiner squeezes the fleshy part of the calf, causing the 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 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.¹⁰

IMAGING AND OTHER DIAGNOSTIC STUDIES

Clinical diagnosis of chronic ruptures can be problematic, and imaging can be useful.

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 superior aspect of the calcaneus (this space is known as the triangle of Kager).

Ultrasonography of a chronic rupture usually demonstrates an acoustic vacuum with thick irregular edges (FIG 1).

T1-weighted magnetic resonance (MR) images will show disruption of signal within the tendon substance, while T2-weighted images show generalized high signal intensity.

DIFFERENTIAL DIAGNOSIS

Acute rupture of the Achilles tendon, rerupture of the Achilles tendon, tear of the musculotendinous junction of the gastrocnemius–soleus and the Achilles tendon.

NONOPERATIVE MANAGEMENT

Consensus is that the most appropriate treatment for chronic Achilles tendon ruptures is surgical.¹²

SURGICAL MANAGEMENT

The management of chronic Achilles tendon tears is technically more demanding than primary repair of acute rupture, as the tendon ends normally will have retracted. Due to the increased gap, primary repair is not generally possible. Operative procedures for reconstruction of chronic Achilles tendon ruptures include flap tissue turndown using one and two flaps, local tendon transfer, autologous free tendon grafts, and allografts.^2,14,17,18 Complications, especially wound breakdown and infection, are frequent following open procedures, and they may require plastic surgical procedures to cover significant soft tissue defects.² A less invasive peroneus brevis reconstruction technique using two para-midline incisions has been described. This technique allows reconstruction of the Achilles tendon preserving skin integrity over the site most prone to wound breakdown. If the gap is greater than 6 cm despite maximal plantar flexion of the ankle and traction on the tendon stumps, peroneus brevis is not sufficient to fill the gap. In these cases, ipsilateral hamstring tendon graft is indicated.^6,8,11

Preoperative Planning

All imaging should be reviewed to estimate the tendon gap.

If the gap in maximum plantarflexion is less than 6 cm, peroneus brevis transfer can be used.^8,11

If the gap is greater than 6 cm, we recommend a free autologous gracilis tendon graft.^7,8

If these tendons have already been used for other reconstructive procedures, alternative surgical options will have to be considered.

Positioning

Under general anesthesia, the patient is placed prone with the ankles clear of the operating table.

A tourniquet is applied to the limb to be operated on. The limb is exsanguinated, and the tourniquet is inflated to 250 mm Hg.

Antibiotic is injected through an intravenous cannula in a dorsal vein of the foot of the leg to be operated on, after exsanguination of the limb and inflation of the tourniquet.

TECHNIQUES

Peroneus Brevis Tendon Transfer for Chronic Achilles Tendon Rupture

Exposure

Three skin incisions are made (TECH FIG 1):

The first incision is a 5-cm longitudinal incision made 2 cm proximal and just medial to the palpable end of the residual tendon.

The second incision is 3 cm long and is also longitudinal. It is 2 cm distal and lateral to the distal end of the tendon rupture. Care is taken to prevent damage to the sural nerve, which lies 18.8 mm lateral to the tendon within proximity to the tendon insertion site and medial to the tendon 9.8 cm above the calcaneus, by making this incision as close as possible to the anterior aspect of the lateral border of the Achilles tendon.