Calcaneal Tuberosity Fractures

Calcaneal tuberosity fractures are rare but important injuries of the posterior tuberosity of the calcaneus, the insertion of the Achilles tendon. They are avulsion injuries, and a displaced fracture needs ORIF to prevent loss of plantarflexion power and equinus contracture.

Incidence. Approximately 1.3-2.7% of all calcaneal fractures. Lee found 20 among 764 calcaneal fractures, 2.6%.

Who. Typically older adults, and more often women: the Carnero-Martin series had a mean age of 57 and was around 62% female, a predominance that reflects post-menopausal osteoporosis. Roughly one patient in five was diabetic (19%), and many of these fractures are insufficiency or Charcot-related avulsions.

Mechanism. In Carnero-Martin 71% were low-energy, a trip or a fall. Less commonly the cause is a direct blow (Lee type II) or high energy. Ipsilateral foot and ankle fractures occur, so assess the whole hindfoot.

The tuberosity. The large, prominent posterior projection of the calcaneus, and the insertion of the Achilles tendon. Its blood supply comes from branches of the posterior tibial artery.

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The Achilles insertion. The tendon is 1.5-2cm wide where it inserts on the posterior tuberosity, and it drives plantarflexion and push-off. The tuberosity is the Achilles footprint, so a tuberosity fracture is an Achilles tendon avulsion.

The sural nerve. Sensory to the lateral foot, it runs 1-2cm posterior to the lateral malleolus and is at risk in the posterior approach.

Mechanism of injury. Sudden plantarflexion with an eccentric contraction of the gastrocnemius-soleus puts the Achilles under excessive tension, and it avulses from the tuberosity with a bone fragment. In osteoporotic or diabetic (Charcot) bone the tuberosity is already weak, and a minor force is enough.

Why displacement matters. The tendon draws the fragment proximally. Plantarflexion power is lost, the patient cannot push off and gait suffers, and proximal migration leads to equinus contracture. Anatomic reduction restores plantarflexion, the Achilles lever arm and gastrocnemius-soleus tension, and prevents the contracture; stable fixation allows early motion.

What CIA means. A posterior tuberosity avulsion through pathologically weak bone, with little or no trauma. Greenhagen notes that CIA fractures make up part of the 1.3-2.7% of calcaneal fractures attributed to reduced bone mineral density, and that in a person with diabetes the avulsion most likely represents a Charcot neuroarthropathy event rather than a simple mechanical failure.

Where Brodsky 3B fits. The Brodsky anatomic classification locates Charcot neuroarthropathy by region. The full classification and its reconstructive principles belong to the Charcot neuroarthropathy topic:

• Type 1 - midfoot, the commonest
• Type 2 - hindfoot
• Type 3A - ankle
• Type 3B - posterior calcaneus, a pathologic avulsion of the tuberosity (os calcis)

Labelling a tuberosity avulsion Brodsky 3B therefore signals a neuropathic, insufficiency mechanism, not a high-energy injury.

When to suspect it. A spontaneous avulsion, or one after trivial force, is a red flag, as is a diabetic or neuropathic patient. Check the sensory examination and blood glucose, screen for previously undiagnosed diabetes and peripheral neuropathy, and assess bone quality before planning fixation.

Why it changes management. Neuropathic or osteoporotic bone gives poor screw purchase, so conventional lag-screw ORIF frequently fails or loses reduction, and suture anchors, a tension band and gastrocnemius recession may be needed. Greenhagen described fragment excision, gastrocnemius recession and double-row suture-anchor Achilles reattachment rather than struggling to fix unfixable bone; the rearfoot AOFAS score improved from 27 to 88 at one year. Anticipate poor bone and be ready to abandon screws for anchors and tendon reattachment.

Three schemes are in use. Lee's describes morphology and the Achilles fibres involved, Beavis's is historical, and Carnero-Martin's is built on displacement.

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History. Posterior heel pain and swelling after a sudden plantarflexion, a fall or direct trauma to the heel. Walking is difficult and weight bearing painful, and the patient cannot push off.

The skin comes first. Inspect the posterior heel for blanching or tenting before anything else. The displaced fragment tents the skin, and in thin, elderly or diabetic patients pressure necrosis can develop within hours; the skin, not the bone, is the time-critical issue.

Inspection and palpation. Swelling of the posterior heel, ecchymosis that may be delayed, and deformity from proximal migration of the fragment. The tuberosity is tender, a gap may be felt at the fracture if it is displaced, and Achilles continuity may be disrupted.

Function. Loss of active plantarflexion is the key finding: the patient cannot push off or perform a single-leg heel raise, which indicates Achilles dysfunction. Passive plantarflexion may be limited and a displaced fracture may produce an equinus deformity. The Thompson test may be positive, and a straight leg raise may be limited by pain.

Radiographs. A lateral, an axial and an AP view:

• Lateral - the best view: shows the tuberosity, the displacement and proximal migration of the fragment
• Axial (Harris) - shows the tuberosity from below and the displacement
• AP - may show the fracture, but is less reliable than the lateral

CT is recommended when displacement is unclear on the radiographs, when the pattern is complex, and when planning surgery, for which it is often needed. It shows the fracture pattern, fragment size and comminution, and measures displacement as step-off.

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When the heel skin is threatened, urgent reduction, closed or open, is mandatory, and it is done within hours of recognising a tented, blanched heel. Closed reduction is a temporising measure to protect the soft-tissue envelope.

The manoeuvre. Unload the Achilles, reduce the fragment, then hold it:

1. Relax the deforming force. Flex the knee and hold the ankle in plantarflexion (equinus) to slacken the gastrocnemius-soleus-Achilles complex that is pulling the fragment proximally.
2. Reduce and decompress. With the muscle relaxed, press directly over the displaced fragment to push it back down onto the tuberosity bed, relieving the skin.
3. Hold and reassess. Immobilise in a well-padded plantarflexion (equinus) splint or backslab, then confirm that skin colour, blanching and capillary refill improve.

When it is not enough. If plantarflexion and manual pressure fail to relieve the tenting or blanching, this becomes an emergency open reduction to decompress the skin directly; do not wait for an elective list when the heel skin is white. Even a successful closed reduction rarely gives a stable definitive result, because the strong Achilles pull re-displaces the fragment, so definitive fixation still follows once the soft tissues allow.

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The decision. Displacement and the extensor mechanism decide it. Most fractures are displaced and are fixed; the rare non-displaced fracture with an intact extensor mechanism can be treated in a cast.

Timing. Definitive fixation within 2 weeks if possible, before healing. Threatened skin cannot wait for that: it is reduced first, as above.

Choosing the construct. Tension band wiring is the preferred technique: it converts the tensile pull of the Achilles into compression at the fracture and allows early motion and weight bearing. Screws, combined constructs, plates and suture anchors are the alternatives, and the evidence does not settle the choice between them (see Controversies).

Approach. A posterior midline or posterolateral approach exposes the tuberosity. Identify and protect the sural nerve.

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Sural nerve injury. The nerve lies in the path of the posterior approach. Identify and protect it; a symptomatic neuroma is excised.

Equinus contracture. It follows proximal migration of the fragment and delayed treatment. Established contracture is treated with stretching, serial casting or surgical release.

Soft-tissue failure and nonunion. Skin risk can dominate fracture management. The cases below show posterior soft-tissue failure, infection after delayed treatment, and nonunion after non-operative care.

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The ankle is protected in a short leg cast or boot, non-weight bearing initially (2-4 weeks). Ankle range-of-motion exercises start early if fixation is stable, and physiotherapy concentrates on plantarflexion strengthening.

The percentage ranges below are conventional teaching estimates commonly quoted for this injury; the published series are small and report results differently (e.g. Yu 2013 reported 90% excellent/good AOFAS outcomes after screw fixation in 10 followed patients), so treat these figures as approximate rather than measured.

Long-term plantarflexion. With proper treatment 80-90% restore normal strength; without treatment 20-30% develop permanent weakness. Displacement, delayed treatment and inadequate fixation are the risk factors.

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Global Epidemiology

• Rare injury: roughly 1.3-2.7% of all calcaneal fractures across published series
• Bimodal pattern: low-energy insufficiency avulsions in elderly osteoporotic women (Lee type I) and higher-energy or direct-blow patterns in younger men
• Strong association with osteoporosis and diabetes/Charcot neuroarthropathy; diabetic prevalence around 19% in surgical series

Society Guidance and Practice Points (Side by Side)

Registry and Resource-Setting Notes

• No arthroplasty registry applies; evidence is from institutional series, so practice variation is wide and surgeon-dependent.
• High-resource settings: ready access to CT/MRI, multiple implant options (tension band, cannulated screws, suture anchors) and combined ortho-plastic cover for threatened skin.
• Limited-resource settings: reliance on radiographs alone, K-wire and cerclage-based tension band constructs (low cost, effective), and a lower threshold for fragment excision and Achilles reattachment when implants or soft-tissue cover are unavailable. Urgent reduction to save skin remains universal and equipment-independent.

The evidence base for these fractures is limited to small retrospective series and case reports, so several questions remain genuinely unsettled:

• Which classification to use - the displacement-based prognostic classification has not yet been validated in larger cohorts.
• Fixation construct - tension band wiring, large cannulated lag screws, plate fixation and suture anchors are all described, and no comparative trial establishes superiority. Fragment size, bone quality and surgeon preference drive the choice rather than high-level evidence.
• Fragment excision versus fixation - with small fragments or very poor (neuropathic or osteoporotic) bone, some advocate excision with Achilles reattachment plus gastrocnemius recession.
• Urgency threshold - there is consensus that threatened skin demands urgent reduction, but the exact displacement or skin-tenting threshold that mandates emergency surgery is not precisely defined.
• Gastrocnemius lengthening - routinely addressing gastrocnemius-soleus tightness at index surgery to reduce re-displacement is advocated by some (Banerjee) but not standardised.
• Hardware removal - tension band wires are frequently prominent in this subcutaneous location; rates and timing of elective removal vary widely.