Endgames Case Report

A case of sudden ankle pain

BMJ 2012; 345 doi: https://doi.org/10.1136/bmj.e4420 (Published 24 July 2012) Cite this as: BMJ 2012;345:e4420
  1. Dominic Yue, foundation year 21,
  2. Jasmine Ho, foundation year 22,
  3. Nawfal Al-Hadithy, core trainee year 22
  1. 1Royal Free Hospital, London NW3 2QG, UK
  2. 2Lister Hospital, Stevenage, SG1 4AB, UK
  1. Correspondence to: D Yue domyue{at}doctors.org.uk

A 55 year old man presented with a sudden onset sharp pain in his right lower calf. It occurred while he was lunging forward in a game of tennis, and he had to stop playing. The initial pain, described as “like a hammer blow,” subsided, and on admission to hospital his only symptom was discomfort around the posterior aspect of his right ankle. He was able to weight bear and mobilise with some difficulty. He had no other injuries, had not previously experienced trauma to the area, and was fit and well apart from taking allopurinol for gout. There was no family medical history of note. He is a non-smoker and drank alcohol occasionally.

On examination, the right lower calf area was swollen and mildly tender. A depression was palpable along the Achilles tendon about 3 cm proximal to the site of tendon insertion at the calcaneus. He was neurovascularly intact and the range of movement was unaffected. The Simmonds-Thompson test was positive. Routine blood tests were unremarkable and a radiograph of the ankle showed no evidence of bony injuries.

Questions

  • 1 What is the most likely diagnosis?

  • 2 What are the risk factors for this condition?

  • 3 What would you expect to find on physical examination?

  • 4 What further investigations would you do?

  • 5 How would you manage this patient?

Answers

1 What is the most likely diagnosis?

Short answer

Spontaneous rupture of the Achilles tendon.

Long answer

The Achilles tendon, also known as the tendocalcaneus, is formed from the fibres of the soleus and gastrocnemius muscles and inserts into the calcaneus. Despite being the largest and strongest tendon in the body, it is the most commonly ruptured tendon in the lower limbs and comprises around 20% of all large tendon ruptures.1 2 Spontaneous rupture has an incidence of 0.02% in the general population.

It most commonly occurs in active people, during the fourth to fifth decade of life, often while performing high energy movements with uneven loading on the Achilles tendon.3 Sporting activities are a common setting for this injury, and about 60% of cases are related to ball games.4

Commonly, people who only occasionally participate in sport describe a “pop” or “snap” sensation and a sharp sudden pain after an explosive movement. Injury is often reported to result from a push-off mechanism or a sudden resisted dorsiflexion of the foot.5 The injury occurs more often in males than in females, but the reported ratio varies greatly, ranging from 2:1 to 12:1.6

2 What are the risk factors for this condition?

Short answer

Ageing, abnormal biomechanical stress on the tendon, and the use of steroids and fluoroquinolones. There is also a predisposition with certain systemic conditions, especially rheumatological diseases.

Long answer

Intrinsic risk factors include continual hyperpronation of the foot, discrepancies in leg length, and obesity, all of which cause tensile loads to be unequally distributed.7 With increasing age, the vascularity of the Achilles tendon decreases, particularly the area 3-6 cm proximal to the tendocalcaneal insertion, predisposing to ischaemic ruptures.8 Injury to the proximal Achilles tendon at the musculotendinous junction can also cause tears. The above biomechanical variations in the tendon cause degeneration in the microstructure and reduce the ability to absorb shocks.

A common extrinsic factor is chronic use of steroids or fluoroquinolones (such as ciprofloxacin).1 9 Apart from systemic usage, local injections of corticosteroids (for treating Achilles tendinopathies) have been purported to increase rupture rates.10 11 Poor technique during physical activity or training can lead to uneven loading on the tendon and contribute to microstresses within the tendinous tissue. In addition, sensory deficits that decrease joint proprioception allow for persistent malpositioning of the foot and ankle unit, also increasing uneven loading.12 This alone may not directly bring about a tendon rupture but is one of multiple predisposing factors, such as rheumatoid diseases, chronic renal failure, diabetes mellitus, systemic lupus erythematosus, and polymyalgia rheumatica.13 Our patient had gout, but the evidence attributing gout to Achilles tendon rupture is scarce. Tendon rupture was reported in a man who had an extensive personal and family history of gout, but he weighed about 18 stone (114 kg), and such a heavy weight independently contributes to biomechanical stress at the Achilles.14

3 What would you expect to find on physical examination?

Short answer

Swelling around the posterior aspect of the ankle with tenderness and often a palpable gap along the tendon. Reduced mobility, difficulties during active plantar flexion, and positivity on the Simmonds-Thompson test.

Long answer

On presentation, the patient may have pain, but one study found that about a third of patients had none.15 If present, the pain is typically described as that felt after a kick or blow to the back of the heel. The area may be swollen and bruised. Swelling may extend into the whole calf area. It is important to look for other injuries that may have occurred at the same time and examine the whole gastrocsoleus-Achilles unit. On palpation, there may be tenderness in the area of the tendon, with a palpable gap or depression along its length, but this may be masked by swelling or formation of a haematoma. Loss of plantar flexion power may be seen in the foot of the affected side, but patients can usually walk, albeit with some difficulty. They can often bear weight but will have problems standing on tiptoes. A common mistake is to rule out rupture of the Achilles tendon in patients who can walk or retain some degree of plantar flexion movement. These actions are not facilitated by the Achilles tendon alone. Gravity as well as the posterior tibialis, peroneal, and plantar muscles contribute to plantar flexion.

The Simmonds-Thompson test is the main clinical test for rupture of the Achilles tendon.16 17 A typical finding in complete ruptures (positive test result) is failure of the foot to plantar flex when the calf is squeezed (fig 1). However, the test cannot distinguish reliably between partial and complete ruptures.18 19

Figure1

Fig 1 A negative Simmonds-Thompson test (top) showing normal plantar flexion of the foot on calf squeezing and a positive test on the contralateral side (bottom)

4 What further investigations would you do?

Short answer

Most Achilles tendon ruptures can be diagnosed clinically, but an ultrasound scan of the Achilles tendon reliably provides a definitive diagnosis if there is any doubt. A radiograph of the relevant ankle may also help rule out other injuries, especially if clinical suspicion is low.

Long answer

Blood results are usually normal but they can help to exclude an underlying predisposition to tendon rupture, such as an inflammatory condition, renal impairment, or diabetes. If the presentation is acute and the clinical diagnosis is clear, imaging may not be needed. A radiograph of the ankle can help rule out other injuries that may have occurred at the same time as an Achilles tendon rupture, such as bony injuries (for example, calcaneal avulsion fracture). However, radiography is not a reliable method for picking up tendon rupture itself.

Ultrasound is a non-invasive, reliable, economical, and widely available method that has been recommended as a first line investigation in patients with a clinical suspicion of a ruptured Achilles tendon. It can help delineate between complete and partial ruptures, estimate the size of the defect, detect the presence of haematoma, and allow for a dynamic assessment of the tendon (fig 2).20 21 However, all ultrasound scans are subject to operator skill and interpretation can be difficult. Magnetic resonance imaging is accurate and can reliably distinguish incomplete ruptures from degenerative and inflammatory changes such as paratenonitis, tendinosis, or retrocalcaneal bursitis.22 23 One study showed that it may have a higher sensitivity and similar specificity to ultrasound.24 However, it is expensive, has limited availability, and the final images are static snapshots.

Figure2

Fig 2 Ultrasound image of the patient’s right Achilles tendon, showing a 29 mm defect. Normal looking tendon is seen either side of the red arrows, but in between the continuity of the tendon is disrupted, with a visible gap on one side. (A) represents a shadow caused by a frayed end that has fibres running in different directions to the rest of the tendon. (B) represents tendon debris and haematoma in between the tendon ends

5 How would you manage this patient?

Short answer

Manage conservatively with an equinus cast or surgically with an open or percutaneous tendon repair. In all cases, a comprehensive rehabilitation programme is central to helping the patient regain usual mobility, strength, and function.

Long answer

An acute Achilles tendon rupture can be managed conservatively or surgically. There are many surgical methods of tendon repair, but a review of three trials found that no technique was definitively superior.25 Several studies have reported lower rates of re-rupture after surgical repair than after conservative management.26 27 28 Particularly in young and active people who present acutely, systematic reviews have shown that open surgical treatment significantly reduces the risk of re-rupture and increases strength, and that this may offset the risks associated with surgery.25 29 One of the main problems with surgical repair is a higher incidence of complications such as infections, skin necrosis, and sinus formation because the Achilles area tends to heal poorly. A meta-analysis found that the incidence of minor and moderate complications can be up to 20 times higher in surgically managed patients than in those managed conservatively.30 Percutaneous techniques have been developed to minimise wound complications, but the associated risk of sural nerve injury means that an open technique is often favoured.31

Conservative management—the application of an equinus cast for two months and walking on a raised heel for a further month—has been reported to have good outcomes.32 This approach, if instigated within 48 hours, resulted in strength of plantar flexion, range of movement, and re-rupture rates that were comparable to those seen in the surgical group.33 A randomised trial had similar results but reported fewer wound complications and earlier return to work in the conservative group.28

Whichever management route is followed, a comprehensive rehabilitation programme is essential to restore the patient’s normal strength and function as well as decrease swelling and pain. Some have reported that early mobilisation coupled with a restricted range of motion may help reduce rehabilitation time with no increase in complications.34 35 Evidence also supports the safety of an immediate full weight bearing mobilisation regimen, which improved clinical and functional outcomes without deleterious effects on the tendons.36

Patient outcome

Our patient underwent repair of the right Achilles tendon under general anaesthesia with the use of a tourniquet. The tendon was exposed through a paramedian approach and the ends were freshened. A Krakow-type core repair was performed to achieve close and tension-free approximation of the tendon ends. Skin closure was performed with absorbable sutures. Dorsal plaster of Paris backslabs were applied below the knee with the foot in equinus position. After surgery, he had six weeks of non-weight bearing on crutches and regular plaster changes to reduce the degree of equinus. This was followed by a walking boot with three wedges to raise the heel, with one wedge removed every two weeks. He was referred to physiotherapy for a rehabilitation programme, starting with partial and then full weight bearing exercises.

Notes

Cite this as: BMJ 2012;344:e4420

Footnotes

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

  • Patient consent obtained.

References

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