Achilles tendon rupture

Introduction

Achilles tendon ruptures are the most common tendon ruptures of the lower extremity. They can occur at any age, but are most common in the third to fifth decade. There is a significant male preponderance. The classic description is the "weekend warrior" athlete.

Anatomy

The Achilles tendon is the common tendon of the gastrocnemius and soleus muscles and provides their attachment to the calcaneus. The soleus muscle arises from the posterior tibia while the gastrocnemius arises from the posterior distal femur. This allows the the gastrocnemius to be effective with an extended knee and the soleus to be more effective with a flexed knee. The tendons from both muscles coalesce just distal to the musculotendinous junction to form the achilles tendon. The tendon then has a relative avascular portion 2-6 centimeter above the insertion. The tendon also rotates approximately 90 degrees during during its course with the gastrocnemius fibers being more lateral. The tendon then inserts upon the posterior calcaneus primarily along the posterior tuberosity with slightly more medial than lateral extension (Chao F&A 1997, Lohrer CORR 2008).

Pathogenesis

A relatively hypovascular area exists approximately 2-6 cm above the insertion into the calcaneus. This hypovascularity has been implicated in disorders of the tendon. Age-dependent changes in collage cross-linking result in increased stiffness and loss of viscoelasticity may predispose the tendon to rupture. Mechanisms associated with ruptures include sudden forced dorsiflexion of the ankle (eccentric contraction of the gastrocnemius and soleus), pushing off with the weight-bearing forefoot while extending the knee, and from a laceration or direct blow to the contracted tendon.

Classification

Achilles tendon ruptures are partial or complete. Ruptures can also be divided into acute traumatic ruptures, chronic ruptures or chronic attritional ruptures. However, ruptures are often due to a combination of age related attrition and an acute traumatic incident.

Patient History and Physical Findings

The patient with Achilles tendon rupture presents with pain in the area of the Achilles tendon. Pain is often described as an intense burning sensation or sharp stabbing pain.  Patients may hear an audible pop after landing or pushing off and usually describe a feeling of being kicked, hit, or shot in the heel. A small percentage of patients will have had pro-dromal symptoms. In the presence of complete tear, patients will experience significant ankle plantar flexion weakness. However, many patients continue to be able to actively plantarflex the ankle using accessory muscles. This may confound some examiners and result in a missed diagnosis.

Physical findings include a visible soft-tissue depression in the posterior ankle on observation. Patients may be unable to walk or walk with a limp secondary to weak or absent pushoff. The tendon defect can often be palpated along the posterior leg and ankle. Absence of active plantarflexion is often expected, but many patients effectively recruit other muscles to plantarflex against manual testing. However, they are rarely able to perform a single leg heel raise. With the patient in the prone position and the knees extended, the Thompson squeeze test is executed by squeezing the calf muscle and observing the presence or absence of resultant ankle plantarflexion and comparing with the contralateral side. Another helpful test is to observe the resting position of the ankle compared to the unaffected side with the patient prone and the knees flexed to ninety degrees.

Imaging and Diagnostic Studies

Radiographs are rarely diagnostic. Ultrasound and MRI can accurately demonstrate ruptures, but are rarely necessary with classic clinical findings. These studies may be helpful when the diagnosis is unclear.

Treatment

Treatment for acute achilles tendon ruptures can be operative or non-operative and much controversy exists. Historically, the pendulum swung towards operative treatment (especially of younger, healthier patients) because of the much lower reported re-rupture rate (2% for surgical and 11-30% for non-surgical) accepting the trade-off of potential wound complications. Recent investigations have reported much better results with non-operative treatment, often using aggressive functional rehabilitation protocols.

Non-operative

Conservative treatment varies and classically involved casting in a long leg cast with knee flexed and ankle in equinus (2-3 weeks), then short leg casting (8 weeks). Non-weight bearing was typically recommended initially (the first 6 weeks). More recent approaches include functional bracing with immediate weight-bearing. These, more aggressive protocols describe immediate full weight-bearing in a functional brace or pre-fabricated boot. Patients are started with with the ankle in up to 45 degrees of plantar-flexion and gradually decreased to neutral over 6-12 weeks. They often perform active plantar-flexion exercises with restricted dorsi-flexion during that time then graduate to more aggressive strengthening protocols.

Operative

Operative treatment has evolved to include both open, limited open and percutaneous techniques. The classic open approach involves a longitudinal incision approximately 1 cm medial to the tendon to avoid irritation by footwear.  The incision should be carried straight through the skin, subcutaneous tissue to tendon sheath (paratenon) to minimize postoperative wound complications.  Careful preservation of the paratenon is important for later closure and gliding of the tendon. The ends of the tendon are gently debrided and then re-approximated with a large nonabsorbable suture. This may vary from 2, 4, or 6 strand repairs (4 being the most common) and Bunnell and Krackow techniques have been reported. There is some controversy about the benefit of an epi-tenon stitch. Special attention should be directed to the tension of the repair and it should be matched as close as possible to the contralateral side. The plantaris is often available for local supplementation if the achilles tissue is poor. More significant disruption may require tendon transfer utilizing the flexor digitorum longus, flexor hallucis longus, or peroneals.

Percutaneous techniques have become more popular. Several devices (Integra Achillon, Teno-lig) have been promoted to minimize the risk of entrapment of the sural nerve that is the major complication associated with percutaneous repairs. Typically, a small (1cm) incision is made at the rupture site (either transverse or longitudinal) allowing visualization of the rupture. The proximal tendon is grasped with a clamp and then sutures are passed percutaneously through the tendon more proximally and pulled into the tendon sheath and out the small incision. The process is repeated for the distal portion and then these suture are tied together. The theoretical benefits include less disruption of the tendon sheath (and therefore less disruption of the blood supply and better tendon gliding), and less risk of wound complications. The drawbacks can include an increase risk of sural nerve entrapment due to poor visualization and poor purchase of the tendon ends.

Limited open techniques use hybrid elements of open and percutaneous techniques to minimize tissue disruption. The principles of stable fixation, appropriate tendon length, careful soft tissue handling, and protection of nervous structures must be kept in mind with any approach.

Repair of neglected Achilles ruptures typically involves removing intervening scar tissue, lengthening of the proximal portion of the tendon, and supplementation with soft-tissue advancement and/or tendon. This is further described elsewhere.

Pearls and Pitfalls

1. It is important to restore the tension in the gastrosoleus musculotendinous unit following surgical repair. Both legs may be included in the surgical field so that the tension in the uninjured side can be compared with the one that is being repaired to avoid problems with too long or too short a tendon.
2. In an open repair, minimize retraction of the skin edges to avoid wound edge necrosis. 
3. For an acute repair, tourniquet control is rarely necessary.
4. Always be aware of the location of the sural nerve, just lateral to the achilles tendon.

Postoperative Care

After surgery, patients are commonly splinted for two weeks in equinus and remain non weight-bearing. At two weeks, treatment can differ substantially among surgeons. Some may cast for an additional 4-6 weeks and then transition to shoe-wear with a heel lift. Others may progress from the splint to an Achilles-type Cam Boot that can hold the ankle in varying degrees of equinus. Patients are allowed to weightbear and gradually adjust the Cam Boot to a neutral position by 6-8 weeks postop. Patient are then transitioned to shoes with a heel lift and physically therapy is intensified. Typically athletes may require 6 months to return to adequate playing strength and studies suggest full strength may take 1-2 years to achieve and may never equal the pre-rupture strength.

Outcome

Outcomes are typically quite good, although some patients may never regain full strength. As mentioned earlier, surgical re-ruptures rates are around 2% while non-operative treatment has historical re-ruptures rates up to 35%. Current functional non-operative protocols appear to have a much lower re-rupture rate.

Complications

Operative treatment

• Rerupture (~2%)
• Skin complications (~5%)
• Deep infection(~1%)
• Stiffness
• Keloid
• Thickened tendon in repair area

Non-operative treatment

• Rerupture (10-30%)
• Decreased strength

Red Flags and Controversies

• Controversy exists regarding operative versus non-operative treatment. Many advocate non-operative treatment due to similar strength, power, range of motion, and functional level results obtained with conservative and operative treatments. Others have recommended surgical repair in athletic patients due to a lower rerupture rate (2-3 versus 10-30%).
• Carden et. al. reported non-operative results comparable to operative results when ruptures were casted in the first 48 hours.
• Open vs Percutaneous technique for operative treatment. Studies suggest wound complications and re-rupture are higher with open techniques but sural nerve entrapment is a problem with percutaneous techniques. See Percutaneous Achilles Repair.

As mentioned, controversy exists, but it is generally thought that surgical treatment results in good return of strength, endurance, and power with a low rerupture rate.

References

• Molloy A, Wood EV. Complications of the treatment of Achilles tendon ruptures.
  Foot Ankle Clin. 2009 Dec;14(4):745-59. Review. PubMed PMID: 19857846.
• Aktas S, Kocaoglu B. Open versus minimal invasive repair with Achillon device.
  Foot Ankle Int. 2009 May;30(5):391-7. PubMed PMID: 19439137.
• Neumayer F, Mouhsine E, Arlettaz Y, Gremion G, Wettstein M, Crevoisier X. A
  new conservative-dynamic treatment for the acute ruptured Achilles tendon. Arch
  Orthop Trauma Surg. 2010 Mar;130(3):363-8. Epub 2009 Apr 2. PubMed PMID:
  19340434.
• Suchak AA, Bostick GP, Beaupré LA, Durand DC, Jomha NM. The influence of early
  weight-bearing compared with non-weight-bearing after surgical repair of the
  Achilles tendon. J Bone Joint Surg Am. 2008 Sep;90(9):1876-83. PubMed PMID:
  18762647.
• Metz R, Verleisdonk EJ, van der Heijden GJ, Clevers GJ, Hammacher ER,
  Verhofstad MH, van der Werken C. Acute Achilles tendon rupture: minimally
  invasive surgery versus nonoperative treatment with immediate full
  weightbearing--a randomized controlled trial. Am J Sports Med. 2008
  Sep;36(9):1688-94. Epub 2008 Jul 21. PubMed PMID: 18645042.
• Carden DG, Noble J, Chalmers J, Lunn P, Ellis J, 1987. "Rupture of the calcaneal tendon. The early and late management." J Bone Joint Surg Br 69 (3): 416-20. PubMed PMID: 3294839.

Related Topics

Achilles tendon rupture (Orthopaedia Main)

Useful Internet Resources

Tendo Achilles Rupture (Orthopaedic Web Links) [OCOSH Code: C21.866.761_WI_R_H]