The Achilles tendon is the most commonly ruptured tendon and the incidence is increasing.[1-3] Unfortunately, 20% to 25% of acute Achilles tendon ruptures are misdiagnosed initially.[1,4] Diagnosis is based on history and physical examination. Use of MRI or ultrasound is not indicated unless there are equivocal physical exam findings.
Common mechanisms include pushing off with the weight-bearing foot while extending the knee; a sudden, unexpected dorsiflexion of the ankle; or violent ankle dorsiflexion of a plantar flexed foot. Patients often describe feeling as if they were kicked in the back of the ankle. Some will have minimal discomfort and may be weight-bearing. They may describe a “pop” at the time of injury. Fluoroquinolone or steroid use, diabetes, or chronic renal failure can increase the risk of rupture but make small contributions to overall incidence.[5,6]
The Thompson test is considered to be the most accurate—it is positive in 96% to 100% of acute ruptures.[7-9] Other physical findings include a palpable tendon gap, tenderness, and possibly swelling/bruising depending on injury acuity. In the prone position with the patient’s feet off the examining table, the injured foot will hang in more dorsiflexion than the contralateral foot. The patient may be able to plantarflex and the Thompson test may result in some movement, but in both cases the injured side will be weaker and decreased compared with the uninjured side. This is due to other musculotendinous structures that pass the ankle posteriorly.
Treatment Treatment of Achilles tendon ruptures is currently undergoing transition. Traditional treatment involves 12 weeks of immobilization. If treated surgically, the tendon is repaired and the foot immobilized in equinus. Immobilization could be splinting followed by casting at 2 weeks, or, more recently, a cast boot with heel wedges. If treated conservatively, the foot is immobilized in equinus. Both approaches are non-weight-bearing and the foot is incrementally brought up to a neutral position over approximately 6 weeks by recasting or removing the heel. The second 6 weeks have the foot immobilized at 90 degrees. Some surgeons may opt to allow protected weight-bearing at this point. If the injury is identified and treatment started within 14 days, the primary difference between the options is higher re-rupture rates with conservative management (meta-analyses found this to be approximately 3% vs 13%)[10,11] vs the risks of surgery. Some surgeons believe surgical repair has better functional outcomes, but this has not been conclusively demonstrated.
A multicentre study in 2010 using an accelerated functional rehabilitation protocol changed the landscape. It found no clinically significant differences in outcome or re-rupture rates. This protocol involved limited immobilization with early motion. The original protocol (see Table) has since been slightly modified by various surgeons. This approach is currently used by a significant number of orthopaedic surgeons in BC. Other studies have validated the results of this approach.[12-15] There may be an advantage of earlier return to work with surgical intervention. Surgical treatment remains the primary option for patients in whom treatment is begun more than 14 days after injury.
Acute Achilles ruptures are most common in male weekend warriors. Diagnosis is made with history and physical examination. Treatment can be conservative or surgical, with accelerated function rehabilitation offering conservative management the advantages of surgery without the risks. The conservative approach can be used only if treatment is initiated within 14 days of injury. A patient diagnosed with acute Achilles rupture should be immediately made non-weight-bearing, immobilized in equinus, and referred to the local orthopaedic surgeon on call. This will allow all treatment options to be available to the patient and treating surgeon. —Derek Smith, MD, FRCSC WorkSafeBC Orthopaedic Specialist Advisor