Spontaneous Avulsion Fracture Of The Calcaneus In A Non-Diabetic Patient
L Thomas and GW McNaughton
Emergency Department, Royal Alexandra Hospital, Corsebar Road, Paisley PA2 9PN
Correspondence to: Dr McNaughton: gordon.mcnaughton@rah.scot.nhs.uk
SMJ 2006 51(3): 50
Doctors working in
Emergency Medicine are well aware of the common mechanism of injury causing and
the clinical appearances of fractures of the calcaneus.
We report a rare case of an avulsion fracture of the calcaneus. Although
avulsion fractures are a well-recognised complication of diabetic neuropathy
they can occasionally occur in non-diabetic patients. The pathology and
management of these fractures is further discussed.
Key words: spontaneous avulsion fracture calcaneus
Introduction
Fractures of the calcaneus have been estimated to account for 2% of all fractures. However avulsion fractures of the posterior aspect of the calcaneus are very rare and account for as few as 3% of all calcaneal fractures.1 They are well recognised in diabetic patients, particularly those with peripheral neuropathy, 1,2,3 and can occur from relatively minor injuries but it would appear to be unusual for these fractures to occur spontaneously.1
An eighty-six year old lady presented to the Emergency Department with a painful right heel that had developed the previous day. There was no history of trauma. She was able to weight-bear with difficulty but unable to transfer. There was no history of diabetes and blood glucose measurement was normal. Examination revealed swelling and bruising around the heel with marked tenderness of the calcaneus. The Achilles tendon was noted to be intact and there was no neurovascular deficit. A radiograph showed an avulsion fracture of the calcaneal tuberosity. (fig. 1)
She was referred to the orthopaedic team and initially treated with a below knee plaster with the foot in the neutral position for four weeks. At this stage examination revealed full pain-free movement at the ankle with some shortening of the Achilles tendon. Further review at two months confirmed good function.
The common association of high falls with landing directly on to the heel causing a fracture of the calcaneus is well known and it is standard teaching in emergency medicine to examine the heels in all patients with such a mechanism of injury.4 Less well known is that fractures of the calcaneus can occur with minimal force and can occasionally occur spontaneously. This is likely to be related to the avulsion of the bony fragment by the pull of the Achilles tendon from sudden contraction of the calf muscles.1 Spontaneous avulsion fractures of the calcaneus are well recognised in diabetic patients and this may be how the disease first presents.5 Here the fracture is thought to be a neuropathic injury. 3 They have also been described in patients with osteoporosis and secondary hyperparathyroidism.2
The treatment of calcaneus avulsion fractures is traditionally based on the degree of displacement of the bony fragment.3 Closed manipulation may fail to achieve adequate reduction and open reduction with internal fixation is required in most cases. 1,6,7 Various techniques have been described including fragment fixation with cancellous screws, Kirschner wires, Steinmann pins, metal wire or Nylon sutures.5 The leg is then usually placed in a below knee plaster with the foot in equinus for a number of weeks. The aim of surgical reduction is to restore Achilles tendon function and prevent functional loss due to a shortened heel cord. 7 The likelihood of tendon impairment increases as the displacement of the avulsion fracture increases,5 and the necessity for surgical reduction is therefore based on Achilles tendon function.
Although this case report outlines a rare and unusual presentation of a calcaneal fracture it does highlight the need to reduce the threshold for x-raying the elderly when they present with musculoskeletal problems. Not only might this minimise the risk of a missed injury but should ensure prompt and appropriate treatment of any proven fracture.
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