Nicholas A. Ferran and Nicola Maffulli
DEFINITION
Rupture of the Achilles tendon is common.
More than 20% of acute injuries are misdiagnosed, leading to chronic or neglected ruptures.3
Most authors define chronic rupture as a rupture with a delay in diagnosis or treatment for more than 4 weeks.2,8,9
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.14
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.14
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.4
Corticosteroids, fluoroquinolones, previous tendon pathology, and poor vascularity of the Achilles tendon have been associated with rupture.4
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.5
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)12 : positive or negative. False positive may be possible if plantaris is present and intact.
Knee flexion test (Matles test)6 : 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 1957,12 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.6
IMAGING AND OTHER DIAGNOSTIC STUDIES
As clinical diagnosis of chronic ruptures can be problematic, 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 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.8
SURGICAL MANAGEMENT
A delay in presentation of Achilles tendon rupture results in filling of the gap between the ruptured tendon ends with fibrous nonfunctional scar, which needs excision. To reestablish tendon continuity, surgeons may consider the use of the following: (1) the residual Achilles tendon, (2) adjacent tendons, (3) autologous free tendon grafts, (4) allografts.15
FIG 1 • Ultrasound of ruptured Achilles tendon. Acoustic vacuum demonstrated with irregular edges.
Preoperative Planning
All imaging should be reviewed to estimate the tendon gap.
If the gap in maximum plantarflexion is 5 to 9 cm, peroneus brevis transfer can be used.7,10,13,16
If the gap is 9 to 12 cm, we recommend a free autologous gracilis tendon graft.5
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.
Approach
The traditional midline longitudinal approach over the Achilles tendon has been associated with wound healing problems and a risk of sural nerve injury when extended proximally.
We do not use the lateral approach, given the high risk of sural nerve injury.
We employ a 10to 12-cm curvilinear approach medial to the medial border of the tendon with sharp dissection through the subcutaneous fat to the paratenon. This incision avoids the sural nerve.13
Maintaining thick skin flaps is vital to reduce the incidence of wound breakdown.
TECHNIQUES
PERONEUS BREVIS TENDON TRANSFER FOR CHRONIC ACHILLES TENDON RUPTURE
The Achilles tendon is exposed by longitudinal incision of the paratenon in the midline for the length of the skin incision.
The ends of the Achilles tendon are freshened by sharp dissection, producing a defect between the freshened ends. The proximal stump is gently dissected out and mobilized distally (TECH FIG 1).
Through the base of the wound, the deep fascia overlying the deep flexor compartment and the compartment containing the peronei muscles can be seen.
The internervous plane lies between the peroneus brevis (supplied by the superficial peroneal nerve) and the flexor hallucis longus (supplied by the tibial nerve).
The peroneus brevis tendon can be identified toward the medial side.
The tendons of the peroneus longus and brevis can be distinguished from each other at this level by the fact that although both are tendinous in the distal third of the lower leg, the peroneus brevis is muscular more distally than the peroneus longus. The deep fascia overlying the peroneal tendons is incised and the peroneal tendons are mobilized.
Make a 2.5-cm longitudinal incision over the base of the fifth metatarsal. Identify the peroneus brevis tendon, place a stay suture in the distal end of the peroneus brevis tendon, and detach the tendon from its insertion and mobilize it proximally.
Deliver the tendon through the posteromedial wound using gentle continuous traction as it is pulled through the inferior peroneal retinaculum. In this fashion, the tendon of the peroneus brevis retains its blood supply from the intermuscular septum.
Weave the peroneus brevis tendon through the Achilles tendon ends.
TECH FIG 1 • Repair of chronic Achilles tendon rupture with peroneus brevis. A. Tendon ends are débrided to demonstrate true defect. B. Proximal stump mobilized into wound. C. Incision made over insertion of peroneus brevis on the base of the fifth metatarsal. (continued)
TECH FIG 1 • (continued) D. Peroneus brevis insertion dissected. E. Tendon passed from lateral to medial in distal stump. F. Tendon passed from medial to lateral in proximal stump. G. Completed repair.
First pass it from lateral to medial through the distal stump via coronal incisions medially and laterally in the Achilles tendon.
Suture the edges of the coronal incisions in the Achilles tendon to the peroneus brevis tendon to prevent progression of the incision that would lead to the peroneal tendon cutting out through the Achilles tendon.
Pass the tendon through the proximal stump from medial to lateral, with the foot maximally plantarflexed.
Suture the peroneal tendon to the Achilles tendon stumps using 3-0 Vicryl. This is usually sufficient, but, if there is a very large defect, the tendon of the plantaris can be harvested, if present. This is then used to reinforce the reconstruction.
In most cases of neglected ruptures of the Achilles tendon, the paratenon is either not present or not viable. If present, one can generally manage to close it over the proximal stump using 2-0 Vicryl.
Close the skin with a continuous 2-0 subcuticular Vicryl suture. Steri-Strips are applied and the wound is dressed.
The tourniquet is deflated and the time recorded.
FREE GRACILIS TENDON GRAFT FOR CHRONIC RUPTURES OF THE ACHILLES TENDON
Make a 12to 15-cm longitudinal, slightly curvilinear skin incision medial and anterior to the medial border of the Achilles tendon.
The paratenon, if not disrupted, is incised longitudinally in the midline for the length of the skin incision.
The Achilles tendon is thus exposed, and gentle continuous traction is applied to the proximal stump of the ruptured tendon to further deliver it into the wound (TECH FIG 2).
Excise scar tissue in both the proximal and distal stumps to reach viable tendon.
TECH FIG 2 • Repair of chronic Achilles tendon rupture with gracilis tendon graft. A. Tendon ends débrided to reveal true defect. B. Gracilis harvested. C. Tendon passed from medial to lateral in distal stump. D. Tendon passed from lateral to medial in proximal stump. E. Completed repair.
If the remaining gap in the Achilles tendon is greater than 9 cm, we proceed to harvest the gracilis tendon.
Make a vertical 2to 3-cm longitudinal incision on the medial aspect of the tibial tuberosity, centered over the distal insertion of the pes anserinus.
A venous plexus is often encountered at the distal end of the wound, and care should be taken to diathermy this.
Carry out dissection deep to the fat both medially and superiorly with a small swab on an artery forceps to expose the sartorius fascia.
Insert a curved retractor and make a curved incision, 1 cm long, along the superior margin of the pes anserinus into the sartorius fascia, taking care to avoid the saphenous nerve.
Use blunt dissection with Mackenrodt scissors to produce a window within the superior border of the sartorius allowing access to the tendon of gracilis.
The gracilis tendon lies more superiorly than the neighboring tendon of the semitendinosus and can be retrieved with a curved Moynihan clip.
As the tendon is brought into the wound, use of an arthroscopic probe helps to identify the possible tendon’s proximal vincular attachments. The vincula are sectioned to achieve distal traction on the tendon.
Before using a tendon stripper to harvest the tendon, all attachments to the tendon must be completely released. An assistant places his or her hand over the calf, and, by applying firm traction longitudinally, excludes the presence of remaining tendinous attachments by the absence of calf tethering.
Harvest the gracilis tendon with the tendon stripper by directing the instrument in line with the tendon fibers, parallel to the thigh.
Once the gracilis tendon is freed of fat and muscle fibers on the back table, pass it from medial to lateral through a small transverse incision in the distal stump of the Achilles tendon made with a no. 11 scalpel blade.
Pull the gracilis tendon proximally and through a small incision in the substance of the proximal stump of the Achilles tendon in a lateral-to-medial direction.
Suture the gracilis tendon to the Achilles tendon at each entry and exit point using 3-0 Vicryl (Polyglactin 910 braided absorbable suture).
Before fully securing the graft, the foot is maximally plantarflexed.
In most patients with neglected ruptures of the Achilles tendon, the paratenon is either not present or not viable. If present, one can generally manage to close it over the proximal stump using 2-0 Vicryl.
Close the skin with a continuous 2/0 subcuticular Vicryl suture. Steri-Strips are applied and the wound is dressed.
The tourniquet is deflated and the time recorded.
POSTOPERATIVE CARE
Before the patient is taken off the operating table, a belowknee plaster-of-Paris cast is applied to the operated leg, with the patient prone and the ankle in maximal equinus.
The operated leg is elevated until discharge.
Patients are usually discharged on the day after surgery after having been taught to use crutches by an orthopaedic physiotherapist.
Thromboprophylaxis is provided with Fragmin 2500 units (dalteparin sodium) subcutaneously once daily, or with 150 mg acetylsalicylic acid orally daily until removal of the cast.
Patients are told to bear weight on the operated leg as able, but to keep it elevated as much as possible at home for the first 2 postoperative weeks.
The cast is removed at the second postoperative week, and a synthetic anterior below-knee slab is applied with the foot in maximal equinus.
The synthetic slab is secured to the leg with three or four removable Velcro straps for 4 weeks.
Patients can graduate to full weight bearing as soon as comfort allows.
A trained physiotherapist supervises the introduction of gentle mobilization exercises of the ankle, isometric contraction of the gastrocsoleus complex, and gentle concentric contraction of the calf muscles. Inversion and eversion of the ankle is also encouraged.
At 6 weeks postoperatively, the patient is followed up and the anterior slab removed.
Physiotherapists supervise gradual stretching and strengthening exercises.
Cycling and swimming are started at 8 weeks postoperatively. Patients are encouraged to increase the frequency of their exercise.
Patients are allowed to return to their sport at the fifth postoperative month.
OUTCOMES
We have reported on 22 patients with chronic Achilles tendon ruptures using peroneus brevis tendon transfer. All were satisfied with the procedure. Despite subjective patient satisfaction, however, objective evaluation demonstrated greater loss of isokinetic strength variables at high speeds, and greater loss of calf circumference when compared with patients undergoing open repair of fresh Achilles tendon ruptures.11
Gallant et al1 assessed eversion and plantarflexion strength after repair of Achilles tendon rupture using peroneus brevis tendon transfer and found mild objective eversion and plantar flexion weakness. However, subjective assessment revealed no functional compromise.
In a study by Pintore et al,11 of 21 patients treated with a free gracilis graft, 2 had excellent results, 15 had good results, and 4 had fair results. All returned to their preinjury occupation. Fifteen returned to leisure activities, including sports such as tennis, squash, and bowling.
Maximum calf circumference was significantly decreased in the operated leg at both presentation and follow-up.
The operated limb showed a lower peak torque than the nonoperated one, but patients did not perceive this as hampering their daily or leisure activities.5
COMPLICATIONS
Wound healing problems
Infection
Sural nerve injury
Rerupture of Achilles tendon
Deep vein thrombosis
REFERENCES
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