DEFINITION

Spontaneous Achilles tendon ruptures are defined as a partial or complete loss of continuity of the distal tendinous portions of the gastrocnemius and soleus muscles with the consequent loss in physiologic equinus of the ankle.

 

 

ANATOMY

 

The gastrocnemius muscle merges with the soleus muscle to form the Achilles tendon, which inserts onto the calcaneus.

 

 

The gastrocnemius muscle is the most superficial muscle and is responsible of plantarflexion of the ankle and propelling the body forward. The soleus muscle is a postural muscle, with no action on the knee joint (it inserts only on the tibia), and also acts as a peripheral vascular pump.

 

The Achilles tendon is approximately 15 cm long, flattened at both its proximal and distal end but rounded in the middle portion. On its anterior surface receives muscular fibers from the soleus up to its insertion.5

 

The Achilles tendon is enclosed by a paratenon, which is a thin gliding membrane, continuous proximally with fascia overlying muscles and distally continuous with the periosteum of the calcaneus. This structure is the most important regarding blood supply to the middle portion of the tendon. Most blood vessels arise from the anterior aspect of the paratenon, which is also the area where neovascularization occurs in tendinopathic patients. A relatively avascular area of the tendon is described near its insertion. Regarding vascular density,

the middle portion of the tendon possesses the lesser density compared to its proximal or distal parts.5

 

PATHOGENESIS

 

The Achilles tendon transmits all the tension generated by the gastrocnemius-soleus complex to the calcaneus. The tendon is elastic and has the capability of deforming and recovering its original length if the strain does not exceed 4%. If the strain is between 4% and 8%, the tendon fibers start to become damaged. At

a strain level of approximately 8%, the Achilles tendon may rupture.4

 

The exact reason why the Achilles tendon ruptures is not known, but there are two main theories, one a degenerative theory and one a mechanical theory. In the mechanical theory, the tendon just suffers strain which exceeds its limit with subsequent failure of the collagen fibrils. In the degenerative theory, a chronic degeneration of the tendon leads to rupture without the need of applying excessive loads.

 

Degenerative tendinopathy is present in most histologic samples from spontaneous tendon ruptures.6 It can be assumed that degenerated tendons will have less tensile strength and rupture under physiologic forces. It has been shown that ruptured tendons have more advanced intratendinous changes than tendinopathic tendons. Degenerative changes are described as hypoxic, mucoid, tendolipomatous, and calcific changes. These

changes are found just in 31% of control tendons.4

 

The origin of tendinopathy is the subject of debate, but the overload theory is the most accepted one, where repeated loading of a musculotendinous unit may result in weakening of the structure and, in some cases, a failure of tendon tissue. If the overload persists and the tendon is unable to heal and/or respond to load over

time, this weakening may increase and compromise a higher percentage of the total tissue.6 The failed healing response of the tendon may relate to numerous factors, such as genetics, age, and gender, among others.

 

Other reasons for Achilles tendon ruptures relate to drugrelated effects. Corticosteroids (local and systemic) have been described as risk factors for tendon ruptures. Fluoroquinolone antibiotic use is also a risk factor for Achilles tendon ruptures. Inflammatory conditions, collagen abnormalities, infectious diseases, and hyperlipidemia have also been associated with tendon ruptures.

 

NATURAL HISTORY

 

When left untreated, Achilles ruptures are named chronic ruptures and they cause great difficulty with ankle plantarflexion. Besides atrophy of the muscle belly, the tendon sheath becomes thickened and adherent to the tendon ends. There is a scar tissue bridging the defect, but this tissue is of poor quality, not as strong as the

intact tendon, and may elongate with time.3

 

Chronic ruptures of the Achilles tendon are mainly surgically treated and conservative measures such as ankle-foot orthoses are only used in low-demand individuals or if the surgery is contraindicated.

 

PATIENT HISTORY AND PHYSICAL FINDINGS

 

Almost all the time, patients present with a typical history of feeling suddenly a “pop” in the calf, often believing that they were hit by someone or somebody. After that, they feel pain and weakness to bear weight. Achilles

tendon ruptures can be missed in up to 25% of patients.4 The diagnosis is clinical, and physical examination is paramount.

 

The identification of loss of physiologic equinus of the ankle will ascertain the diagnosis of a complete Achilles tendon rupture.

 

 

This can be evaluated by the knee flexion test, where the patient is prone holding his knee flexed and the foot falls into neutral or dorsiflexion position.

 

 

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FIG 1 • Patient positioned prone at the end of the table. Observe normal physiologic equinus position of the ankle at the left of the picture compared to the nonphysiologic dorsiflexed position of the ankle at the right side, representing a complete Achilles tendon rupture.

 

 

This same test can be performed prone but with the knee extended, and the relative equinus of the ankle can be compared between the healthy and injured side. Any difference in the plantarflexion resting position of the ankle will indicate a loss of continuity of the Achilles tendon (FIG 1). A gap can be palpated in the rupture site, but this maneuver can be painful.

 

The Thompson test can also be performed, where squeezing of the calf should produce ankle plantarflexion. The test is positive when there is no or limited plantarflexion of the ankle, indicating an Achilles tendon rupture.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Generally speaking, no diagnostic studies are needed to complete the diagnosis of Achilles tendon ruptures.

 

Ultrasonography and magnetic resonance imaging (MRI) have been used as an adjunct to assure clinical diagnosis, but they should be used to evaluate other diagnoses which may individually change the approach.

 

 

Tendinopathy can be evaluated by MRI, which may have a role for follow-up studies.

 

Ultrasonography may have a role when long-standing ruptures are being evaluated, as it will show if there still is hematoma left at the rupture site. If not, this may hinder a minimally invasive approach and incline the surgeon to perform an open repair. Also, ultrasound will detect the presence of deep vein thrombosis, which may delay the operative intervention.

 

Sometimes, imaging studies could be misleading when they show partial continuity of the tendon. In these cases, clinical diagnosis based on loss of physiologic equinus confirms the diagnosis.

 

DIFFERENTIAL DIAGNOSIS

Plantaris rupture, leg contusion, muscle strain, leg fracture, posterior tibialis tendon rupture, deep venous thrombosis, etc.

 

 

 

NONOPERATIVE MANAGEMENT

 

Classically, nonoperative treatment has not been the treatment of choice because of the high rerupture rate associated to this treatment.

 

In the past few years, more information has become available which suggests that functional rehabilitation associated with early weight bearing can deliver rerupture rates similar between operative and nonoperative

treatments.7

 

In the article by Glazebrook,7 10 studies comparing operative versus nonoperative treatment for Achilles tendon ruptures were chosen to be analyzed regarding rerupture rates, complications, and time to return to work, among other factors. No difference was found between both groups except in the time to return to work, which was faster in the operative group.

 

Regarding functional outcomes, only four studies were available for comparison and it is still a matter of controversy because most experts feel that only surgery can yield a better functional outcome.

 

Relative to conservative treatment, it should consider functional rehabilitation as stated earlier, which stands for fast weight bearing and protected motion.

 

SURGICAL MANAGEMENT

 

The best candidates for a minimally invasive approach are patients with acute Achilles tendon rupture less than 10 days from the injury due to the presence of hematoma at the rupture site, which supposedly keeps growth factors present, and the absence of scar tissue, which will hinder a correct healing afterward.

 

Patients should be physiologically active, independent of age, who desire the best probability of returning back to work and sporting activities as close as possible to preoperative levels.

 

Main contraindications should consider general surgical contraindications, as serious medical comorbidities, local infection, and very low physical demand patients or nonambulatory patients.

 

The technique presented here corresponds to a modification of the Dresden surgical technique presented and developed by Amlang1 in 2005.

Preoperative Planning

 

The level of injury should be evaluated preoperatively, clinically, and/or through ultrasound.

 

A sensory evaluation should be performed right before surgery and also to ascertain if there is any preoperative sural damage in order to report it to the patient.

 

Positioning

 

Under regional anesthesia, the patient is placed in prone position with both legs in the operative field.

 

We regularly leave both legs on top of a bolster and sufficiently distal on the operating table to have both feet hanging free from the edge of the table in order to evaluate the physiologic equinus.

 

No tourniquet is used.

 

 

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TECHNIQUES

 

• Exposure

   

  A 2.5-cm paramedial longitudinal incision is made 3 cm above the proximal end of the ruptured Achilles tendon.

   

  It is vital to determine in the operating room, by palpation, the location of proximal stump of the tendon. In this way, we are sure we will be on top of healthy paratenon and tendon (TECH FIG 1A).

   

   

   

  TECH FIG 1 • A. The skin incision is 3 cm proximal to the most proximal aspect of the gap identified by palpation. The incision measures 2.5 cm long and is slightly medial to avoid damaging the sural nerve. B. After skin and subcutaneous dissection, the superficial fascia of the leg is identified, as a fibrous whitish layer. Care is to be taken to isolate it from subcutaneous tissue and eventually the sural nerve. C. The superficial fascia is opened longitudinally with a knife and then with scissors, showing the deeply situated Achilles paratenon, as a red structure. With a rounded tip instrument as a mosquito clamp or suture scissors, the fascia is gently separated from the underlying paratenon in the area surrounding the incision and distally toward the calcaneus.

   

   

  The superficial fascia is identified and dissected free from subcutaneous fat (TECH FIG 1B).

   

  The superficial fascia is incised but the paratenon is not opened and the interval between the fascia and the paratenon is developed.

   

  We regularly use a rounded tip instrument to free up the superficial fascia from the paratenon (TECH FIG 1C).

• Passing the Sutures

   

  Through this developed interval, the suture passers are introduced distally until the calcaneus is reached, one on each side of the tendon (TECH FIG 2A,B).

   

  The suture passers are used to pass three 2-0 polyblend sutures through the distal end of the Achilles tendon, each spaced 1 cm proximal to the previous one, using straight eyed needles.

   

   

   

  TECH FIG 2 • A. One of the suture passers is introduced through the interval between the superficial fascia and the paratenon, being helped by a soft tissue retractor. The suture passer should be introduced gently and superficially, trying to avoid damaging the paratenon and aiming toward either the dorsomedial or dorsolateral aspects of the distal Achilles tendon. B. After getting as near as possible to the calcaneal Achilles tendon insertion, the second suture passer is introduced in the same way and both are held as distal as possible in symmetric positions. Twisting the instruments will allow to appreciate the orientation of the distal aspect of the instrument with its hollow slot which will be the aiming point of the straight needles to be used in the next step. (continued)

   

   

  The slot in the tip of each instrument measures 3 cm in length and therefore can hold the three needles with their sutures at one time, which aids in the aiming and positioning of each consecutive needle.

   

  88

   

   

   

  TECH FIG 2 • (continued) C. Three straight, open-eyed needles, each with an independent 2-0 polyblend suture are passed from one side of the ankle, through the Achilles tendon and through both suture passers and out through the skin on the opposite side. Care has to be taken to ensure correct aiming of the needles through the suture passers. This can be achieved by twisting each suture passer and observing the corresponding twist of the needles. Pulling or pushing the suture passer will correspondingly bend the needles, which is another method to ensure correct positioning of the sutures. After this is done, the needles are passed through and disengaged from the sutures. D. One of the suture passers is retrieved from the proximal incision, pulling all three sutures with it, taking care to hold the opposite suture ends with one hand. Then, the second suture passer is retrieved in the same way, finally retrieving all three sutures through the proximal incision. E. Correct identification of the sutures is performed, matching one end on one side of the repair with its opposite. In this way, all three sutures are identified and kept apart correspondingly. It is of no importance which suture is the most distal one or the most proximal one. F. Each of the sutures is tested, pulling each pair of limbs proximally in order to test the distal grip on the tendon. It is vital to perform this test, as this will tension the distal grip and assure the suture was passed through a healthy portion of the tendon. On the picture, plantarflexion is achieved by pulling on one pair of limbs of a suture, and this test is repeated for each of the three sutures.

   

   

  To check that the needles went through the needle passers, these instruments can be twisted slightly and corresponding bending effect on the needles observed (TECH FIG 2C).

   

  The instruments are then retrieved proximally through the skin incision, one at a time, taking care that the sutures are being secure on one side while being pulled by the contralateral instrument (TECH FIG 2D).

   

  The grip of the three sutures is tested by pulling them hard and being able to obtain plantarflexion at the ankle joint (TECH FIG 2E,F).

• Tying the Sutures and Completion

 

The sutures are driven through the proximal stump with an eyed tapered needle, one at a time, in a crisscross fashion, grabbing the paratenon and tendon underneath as one layer, suturing them consecutively, assuring that at least 5 degrees of additional plantarflexion is achieved compared to the

normal physiologic equinus (TECH FIG 3A-C).

 

One of the threads of the polyblend suture is used with an eyed needle to drive and hide underneath the paratenon the bulk of the knots.

 

The superficial fascia is closed with interrupted 3-0 Vicryl sutures, so as to cover the knots with the fascia. Subcutaneous layer and skin are closed afterward (TECH FIG 3D).

 

A cam walker is applied keeping the ankle in 30 degrees of equinus, which corresponds to 3 cm of surgical towels. An alternative is a hinged cam walker boot, which is our preference now.

 

89

 

 

 

TECH FIG 3 • A. With an open-eyed tapered needle, one limb of each suture is passed in a crisscross fashion from distal-medial to proximallateral (or the opposite depending on the suture position relative to the tendon) and the opposite is done with the other limb of the suture. B. A double surgeon knot is done and tied over the paratenon and slid distally until the knot reaches the distal most aspect of the incision, helping gently the ankle to achieve plantarflexion. C. After the first knot is initially tied, a correct physiologic equinus position of the ankle has to be achieved, adjusting the tension as needed in order to achieve 5 degrees in

excess of plantarflexion. Five additional simple knots are added after each initial double knot. All three

sutures are tied the same way assuring that not more equinus is produced, as this may create too much. Attention is placed on trying to hide each knot by pulling one limb of the knot with an open-eyed needle under the paratenon. D. The superficial fascia is closed with interrupted 4-0 Vicryl sutures and the skin is closed with intradermal 4-0 Monocryl.

 

 

 

90

Sutures

passed distally did not grab the distal stump

• Make sure the straight needles really go through the suture passers. A twisting

motion of the instrument will bend the needle and confirm the correct position. Pulling and pushing the suture passers should deform consequently the needle, also as a confirmation of the correct needle position.

Sutures ▪ Probably due to a too superficial or deep pass of the sutures. When piercing the

slipped distal end of the tendon, make sure to palpate the tendon and have a feel of how proximally superficial it is.

when testing the distal grip

Irregular

tension of one of the sutures

• The first suture sets the equinus position of the ankle. The second suture should

be sutured in order to obtain tension but not increase equinus. It should be tied until it deforms slightly the visible paratenon.

PEARLS AND PITFALLS

 

 

POSTOPERATIVE CARE

 

The ankle is protected in equinus position in a removable boot, allowing weight bearing as tolerated for 2 weeks.

 

At the second week, dorsiflexion active motion is allowed to obtain as close to 90 degrees of dorsiflexion, basically to avoid stiffness and scar adherence.

 

Stitches are removed at 2 weeks postoperatively.

 

Patients are stimulated to bear weight as tolerated and get rid of crutches as soon as the second week postoperatively.

 

Generally, full weight bearing is achieved at the end of the third week and physiotherapy is started.

 

 

The boot is removed at the end of the sixth week. Impact sports are allowed after 12 weeks from surgery. Return to sports is achieved at 5 months postoperatively.

OUTCOMES

We recently reported on 100 consecutive patients with acute Achilles ruptures, operated with the minimally invasive technique described, with a mean follow-up of 42.1 months.2

The mean time to return to work was 56.0 days, and the mean time to return to sports was 18.9 weeks.

The mean American Orthopaedic Foot and Ankle Society (AOFAS) score was 97.7; 98% of patients were satisfied.

The isokinetic evaluation showed good recovery of the involved muscles.

It is worth to mention that instruments are reusable and in this way less costly than the most commonly used devices for percutaneous Achilles tendon ruptures.

These results and the lack of complications compare favorably with other published series.

 

 

COMPLICATIONS

No complications regarding soft tissues and sural nerve damage were reported nor was there any need to remove sutures.

Two reruptures and five cases of deep venous thrombosis were observed.

 

 

REFERENCES

1. Amlang MH, Christiani P, Heinz P, et al. Percutaneous technique for Achilles tendon repair with the Dresden instruments [in German]. Unfallchirurg 2005;108(7):529-536.

    

    

2. Keller A, Ortiz C, Wagner E, et al. Mini-open tenorrhaphy of acute Achilles tendon ruptures: medium-term follow-up of 100 cases. Am J Sports Med 2014;42(3):731-736.

    

    

3. Maffulli N, Ajis A. Management of chronic ruptures of the Achilles tendon. J Bone Joint Surg Am 2008;90:1348-1360.

    

    

4. Movin T, Ryberg A, McBride DJ, et al. Acute rupture of the Achilles tendon. Foot Ankle Clin 2005;10:331-356.

    

    

5. O'Brien M. The anatomy of the Achilles tendon. Foot Ankle Clin 2005;10:225-238.

    

    

6. Rees JD, Maffulli N, Cook J. Management of tendinopathy. Am J Sports Med 2009;37(9):1855-1867.

    

    

7. Soroceanu A, Sidhwa F, Aarabi S, et al. Surgical versus nonsurgical treatment of acute Achilles tendon rupture: a meta-analysis of randomized trials. J Bone Joint Surg Am 2012;94:2136-2143.