Achilles tendon rupture is a common injury mostly seen in middle-aged individuals who overexert themselves playing occasional sports, especially during weekends (weekend warrior). The male to female ratio is 30:1.1
Sudden loaded plantar flexion of the ankle on full weight bearing, especially while hill running and jumping, causes the tendon to snap.
Other mechanisms are sudden unexpected dorsiflexion injury especially when the person falls from a ladder or falls into a hole. It may also occur following a fall from height with ankle plantar flexed.2
The chance of rupture is increased if there are associations like faulty foot biomechanics, poor lower leg flexibility, poor athletic footwear, inactivity, local steroid injections and rheumatic conditions. Intake of drugs like fluoroquinolones2
and anabolic steroids3
have been shown to weaken the tendon. Other conditions also shown to be involved are arteriosclerosis, gout, hyperthyroidism and renal insufficiency.
In this case report, the electric current caused the sudden violent contractions of the calf muscles resulting in snapping of the tendon when the same was done against resistance while the patient was standing. It is reported in literature that electric current causes powerful contractions of the muscle strong enough to produce fractures and dislocations.4 5
If electric current of sufficient magnitude is conducted through a living body, its effect will be to override the tiny electrical impulses normally generated by the neurons, overloading the nervous system and preventing both reflex and volitional signals from being able to actuate muscles. Muscles triggered by an external (shock) current will involuntarily contract, and there is nothing the victim can do about it.4
The patient usually presents with a painful defect in the tendon and difficulty in the push off phase of the gait, which requires strong plantar flexion of the ankle. Despite the straightforward history and physical, about 25% of Achilles tendon ruptures are missed during the patient's first visit.6
There are a few tests to diagnose the tendoachilles injury:
- The Simmonds’ test (also called the Thompson test or Simmonds–Thompson test) is used to test for the rupture of the Achilles tendon. The patient lies face down with feet hanging off the edge of the bed. If the test is positive there is no movement of the foot (normally plantarflexion) on squeezing the corresponding calf signifying likely rupture of the Achilles tendon.
- The O'Brien needle test6 inserts a needle 10 cm proximal to the calcaneal insertion of the Achilles tendon. With passive dorsiflexion of the foot, the hub of the needle will tilt rostrally when the Achilles tendon is intact.
- With the Copeland test7 the patient lies face down on the examination couch. The knee is flexed to 90 and a sphygmomanometer cuff is applied around the bulk of the calf muscle. The cuff is inflated to approximately 100 mm Hg with the ankle plantar flexed. The ankle is passively dorsiflexed by pressure on the sole of the foot. If the Achilles tendon is intact the column will be seen to rise approximately to 140 mm Hg. But if the tendon is disrupted, only flicker of movement is seen on the mercury column.
Confirmation of diagnosis
If the clinical diagnosis is in question, especially in partial ruptures of the tendon or compensation by the toe flexors, an ultrasound examination or a MRI scan will confirm the diagnosis. Ultrasound scanning will show an intact Achilles tendon as a hypoechogenic ribbon-like image contained within two hyperechoic bands. When torn, the distal stump will be grossly thickened and contain an irregular echogenic pattern. The site of the tear will also show a hyperechogenic area consistent with a partially organised haematoma.8
MRI is a better investigation to diagnose the partial tears. The sagittal T1 images can differentiate fat from haemorrhage. It will show high-signal intensity at a rupture site filled with oedema and haemorrhage. In contrast, sagittal T2 images are best for delineating the size of the gap and the condition/orientation of the torn fibres.9
Tendoachilles injury sustained in this case report occurred following a mechanical phenomenon. Electric current, especially from a house hold source (ie, a hair dryer) usually is of low frequency type and is known to produce powerful muscular contractions.
Treatment is by a choice of conservative or surgical management depending upon the age and patient's physical demand. Typically, both non-operative and operative treatment options are offered to patients with particular emphasis on the benefits and risks of each procedure.
The non-surgical management consists of non-weight bearing plaster cast/brace given in gravity equinus for the first 4 weeks followed by bringing the equinus to neutral over the next 4 weeks gradually.10
The surgical management consists either percutaneous11 12
or open repair of the ruptured tendons.
The complications after surgery include skin necrosis, wound infection, sural neuromas, adhesions of the scar to the skin and the usual anaesthesia risks. Problems with wound healing remain the most common and most difficult to manage given the degree of avascularisation around the heel cord. The re-rupture rates following non-operative and operative treatments are highly variable. Several more recent literature reviews and meta-analyses showed re-rupture rate ranging from 12–21% following non-operative management and around 2% following operative management13–15
- Tendoachilles can rupture secondary to electric shock.
- If a patient presents with a history of electric shock, the surgeon should bear in mind tendoachilles rupture during the secondary survey.