Case Report

An Unusual presentation of an unusual injury: atraumatic avulsion of the Achilles tendon

We present an unusual case of rupture of the Achilles tendon. The case presented without trauma and with purely lateral sided symptoms, suggesting a peroneal pathology. Ultrasound imaging confirmed complete avulsion of the tendon insertion, with no bony component. We review the common presentation of this entity and its associated conditions and describe a method of Surgical repair using bone anchors.

Tendo Achillis rupture is a common injury in the United Kingdom. Exact numbers of incidence are not described because there are a large number of variables contributing to injury and a wide variation across racial backgrounds. It usually affects bweekend athletesQ and causes a great deal of social and financial cost to those affected [1]. Usually, the diagnosis is relatively straightforward, with a sharp, painful snap being classic. Other clues to the diagnosis include previous local steroid injections, Achilles tendinopathy, gout, hyperparathyroidism, and recent fluoroquinolone antibiotic use. The mechanism usually involves eccentric loading on a dorsiflexed ankle with the knee extended [2]. It is in this position that the soleus and gastrocnemius muscles are under maximal stretch. Commonly, rupture occurs around 5 centimeters from the insertion point in the os calcis. Historically, this was thought to be a point of vascular watershed [3]. However, more recent evidence has refuted this as a sole cause, and it may, in fact, be one of several contributing factors in a complex etiology [4].

We present a case that not only presented in a very unusual way but that also had a unique pathoanatomical variation. This case highlights the need for clinicians to keep in mind this very common diagnosis and to have a high index of suspicion and low threshold for imaging the area.

A 42-year-old woman presented to our accident and emergency department complaining of sudden-onset pain and swelling in her left ankle while she was walking down the street. There was no history of previous injury or other pathology involving her affected ankle. There was no significant medical history, she was not taking any medica- tion, and she was a nonsmoker. On examination, the tenderness and swelling were limited to the Lateral malleolus only. In particular, there was no palpable defect in her TA; she had a soft calf and a good range of motion, and Simmonds test result was negative. X-rays were also unremarkable (Fig. 1).

The patient was admitted with a diagnosis of peroneal tendon injury. Subsequent ultrasound examination revealed an avulsion of the TA from the os calcis. No other injury was noted. She was taken to theater and underwent operative repair of her TA avulsion using bone anchors to re-attach the tendon insertion (Fig. 2). She had an uneventful recovery and was discharged with a non-weight-bearing plaster in full equinus. After 6 months, she was fully weight-bearing, with a normal range of ankle motion and no other complaints.

Avulsion of the Achilles tendon has been previously described, but it is rare and has always been reported as a consequence of trauma. Previous descriptions have also mentioned the bony injury as being a major component [1,7]. Our case presented in a quite different way; having no bony element and being virtually asymptomatic. This is even more remarkable because there were no other associated risk factors for TA rupture [1,5,6,8].

The presentation of our case highlights the need for clinicians to keep this diagnosis in mind. The woman presented with no trauma, purely lateral swelling and tenderness, and a normal Simmonds test result. None of the usually reliable stigmata of TA rupture were present, even to an experienced senior clinician [9].

We present this case to highlight that TA avulsion can present in the absence of significant trauma. It can present with purely lateral signs. We would like to reinforce the message that one must be wary of a common condition presenting in an uncommon way and have a low threshold for diagnostic imaging when the diagnosis is not apparent.

Fig. 1 X-ray showing no bony component to injury.

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Fig. 2 Intraoperative picture showing avulsion from os calcis and repair.

Case Report

doi:10.1016/j.ajem.2007.03.019

References

Laurence Dodd MD Alistair Tindall MD Richard Hargrove MD Andrew Crockett MBBS Ananthram Shetty MD Kings College Hospital London, SE5 9RS UK

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