Cuboid Fractures

What it is. The cuboid sits in the lateral midfoot as the keystone of the lateral column. Its fractures are rare but important, and they are often associated with Lisfranc injuries and other midfoot trauma.

How common. Under 1% of foot fractures, with a peak at 20-40 years in the trauma population and no clear gender predominance. Those three figures are conventional teaching estimates: no cited series reports a foot-fracture denominator or an age peak. The measured distributions on this page are Fenton's five-pattern split (n=192) and Ruffing's paediatric series (n=16).

Mechanism. High-energy trauma forcing the foot into plantarflexion and abduction. The classic result is the nutcracker fracture, set out in the next section, although in Fenton's series the true crush pattern is a minority and a capsular avulsion is the commonest cuboid fracture.

The bone. The cuboid articulates with the calcaneus proximally, the fourth and fifth metatarsals distally, and the navicular and lateral cuneiform medially. Its blood supply comes from branches of the dorsalis pedis and lateral plantar arteries.

The lateral column. Calcaneus, cuboid and the fourth and fifth metatarsals make up the lateral column, which provides lateral foot stability and carries weight. The cuboid is its keystone and maintains its length.

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The nutcracker. Hermel and Gershon-Cohen described "the nutcracker fracture of the cuboid by indirect violence" in Radiology in 1953 (PMID 13064390). When the forefoot is forcibly abducted on a fixed hindfoot, the cuboid is crushed between the anterior calcaneus behind and the bases of the fourth and fifth metatarsals in front, as a nut is cracked between the two arms of a nutcracker. The compression impacts the bone, causing bone loss and lateral column shortening.

Indirect violence. This is the load-bearing phrase. The bone fails from a force applied at a distance through the lateral column, not from a direct blow, which is why the mechanism must be reconstructed from the history and why the injury is so often missed when the foot looks unremarkable.

Why displacement matters. Displacement costs the lateral column its length. Shortening leads to midfoot collapse and instability, and a malunion leads to lateral column arthritis.

Why fixation. Anatomic reduction restores lateral column length and prevents midfoot collapse. Bone graft is often needed to fill the impaction defect.

The Lisfranc association. A cuboid fracture suggests midfoot instability, so look for a Lisfranc injury whenever the cuboid is fractured. When the midfoot is unstable, both injuries need ORIF.

Fenton. The most widely cited descriptive system, derived from 192 fractures in 188 patients (Bone Joint J 2016) and based on the mechanism of injury. Avulsion is by far the commonest pattern; the classic nutcracker is Type 5.

Displacement. Graded by articular step-off: under 2mm is non-displaced and over 2mm is displaced. Where that 2mm comes from, and how much weight it deserves, is taken up under Management.

Impaction. Impaction determines the need for bone graft.

• No impaction - a simple fracture with no bone loss; ORIF without graft, and the outcome is better than with impaction
• Impaction - compression has caused bone loss; ORIF with bone graft, and the outcome is good if length is restored

History. Lateral foot pain after forced plantarflexion and abduction, with swelling localised to the lateral midfoot and pain on weight bearing. The risk factors are high-energy trauma, a Lisfranc injury mechanism and midfoot instability.

Examination. Swelling sits over the lateral midfoot, ecchymosis may be delayed, and a displaced fracture shows deformity from lateral column shortening. Palpation finds tenderness over the cuboid, Lisfranc joint tenderness if the injuries are associated, and lateral column instability. Midfoot movement is limited and painful, and inversion, eversion, plantarflexion and dorsiflexion all hurt.

Special tests. Cuboid fractures are often associated with Lisfranc injuries, so check for a Lisfranc injury and for midfoot instability:

• Lisfranc stress test - for midfoot instability
• Lateral column stress - pain with stress
• Midfoot alignment - for collapse

Radiographs. AP, lateral and oblique views of the foot. The fracture may show on any of them, and may show better on the oblique. Each view also has its own job:

• AP - check for a Lisfranc injury
• Lateral - lateral column alignment
• Oblique - a view of the Lisfranc joint

Why plain films are not enough. Cuboid fractures are difficult to see on X-ray alone: the fracture line lies in the lateral midfoot and can be obscured by the overlapping tarsal bones. Persistent focal cuboid tenderness with a negative or equivocal radiograph warrants CT or MRI, and oblique views and CT are obtained when pain is disproportionate or column length is uncertain.

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Compare with the other foot. Clinically important lateral column shortening can be difficult to appreciate on an isolated projection. Measuring the column on both sides exposes it.

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CT. CT is usually required, for diagnosis and for planning. It is recommended for a suspected cuboid fracture, an associated Lisfranc injury, or before surgery, and it is often needed to assess the cuboid and the Lisfranc injury together. It is mandatory when swelling, plantar ecchymosis or the mechanism suggests a complex Lisfranc or Chopart injury. What CT shows:

• The fracture pattern and its fragments
• Displacement, with the step-off measured
• Impaction and bone loss
• An associated Lisfranc or Chopart injury
• Lateral column length and alignment

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The decision. A non-displaced, isolated fracture is treated in a cast. ORIF, for the indications below, restores lateral column length and grafts any impaction.

Where the 2mm comes from. It is the general intra-articular fracture convention applied to the cuboid, and no cuboid series has tested it. The only paper on this page that proposes a threshold is Yu, which recommends operating for articular displacement over 1mm or any column shortening, and does so from six patients. Fenton's paper recommended fixation for significant articular disruption or loss of lateral column length, but his 188-patient series describes which fractures were fixed without comparing them with fractures that were not.

How to use it. Treat 2mm as a working convention, not a validated cut-off. Let lateral column length, which every source here agrees on, carry more weight in the decision than the step-off measurement.

Non-operative. For a non-displaced fracture (under 2mm step-off) that is isolated, or where the patient prefers it. A short leg cast, non-weight bearing, for 6-8 weeks, with serial X-rays or CT to monitor healing. Expect a good result in an extra-articular fracture: it is the one pattern with reassuring published data (see Outcomes).

Operative indications. Four are absolute:

• Displacement greater than 2mm step-off
• Part of a Lisfranc injury
• Lateral column shortening
• Impaction with bone loss

Failed conservative treatment and a high-demand patient are relative indications.

Timing. Within 2 weeks if the fracture is isolated; as part of the Lisfranc ORIF if the injuries are associated.

With a Lisfranc injury. Address both injuries, fixing the cuboid as part of the Lisfranc fixation and restoring lateral column length and midfoot stability.

Counselling. Be realistic. The worst prognosis belongs to fractures that involve the midtarsal joint, and even after ORIF the largest operative series of adult nutcracker fractures reported no excellent result; the figures are set out under Outcomes.

Isolated cuboid ORIF. Through a lateral approach to the cuboid, protecting the peroneal tendons (their anatomy is set out below). Restoring length, preventing midfoot collapse and allowing early motion are what ORIF buys.

1. Exposure - expose the fracture, protecting the peroneal tendons
2. Debridement - remove impacted bone fragments and assess the bone loss
3. Bone graft - fill the impaction defect: autograft from the calcaneus or iliac crest, allograft acceptable
4. Reduction - restore lateral column length and reduce the fracture anatomically
5. Fixation - screws (2.7-3.5mm) or a mini-fragment plate (2.0-2.7mm)
6. Verification - confirm the reduction, hardware position and restored lateral column length on fluoroscopy, which shows length and alignment; the joint-surface reduction needs direct visualisation

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Within a Lisfranc fixation. Fixing the cuboid as part of a Lisfranc injury is the most common scenario. The Lisfranc injury is addressed first, through the primary dorsal approach, with screws or a plate. The cuboid is then exposed through a lateral approach, its length restored with bone graft if needed and fixed with screws or a plate, and both injuries are confirmed fixed with lateral column length restored.

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The incidences are conventions. The figures in this table are conventional teaching ranges, not measured rates from a cited cohort: as the Outcomes section sets out, no cuboid series reports complication rates by treatment arm. The sourced anchors are Yu 2012 and Ruffing 2019.

Lateral column shortening. Caused by impaction, inadequate reduction and bone loss, and prevented by bone graft, restored length and adequate fixation. A symptomatic shortening is managed by revision ORIF with bone graft.

Midfoot collapse. Conventionally quoted at 10-15% if untreated, a teaching figure and not a measured cohort rate. It follows lateral column shortening or inadequate fixation, is prevented by restoring length with adequate fixation, and when severe is managed by revision ORIF or midfoot fusion.

Protecting the peroneal tendons is standard advice in cuboid surgery, but why the peroneus longus is uniquely at risk in these injuries rests on an anatomical relationship examiners like to probe.

The peroneal sulcus. The cuboid carries a distinct oblique groove, the peroneal sulcus (groove), on its plantar-lateral surface, running infero-medially from the lateral margin toward the plantar tuberosity. The long plantar ligament roofs the sulcus and converts it into a fibro-osseous tunnel.

The tendons. Peroneus longus (fibularis longus) turns around the lateral cuboid and enters the sulcus to cross the sole obliquely, inserting on the plantar base of the first metatarsal and the medial cuneiform, where it is a key stabiliser of the medial (first-ray) column and the transverse arch. Peroneus brevis lies more superficially and inserts on the fifth metatarsal base.

Os peroneum. A sesamoid within the peroneus longus tendon, lying at the level of the calcaneocuboid joint in a variable minority of feet, and it may be bipartite. On radiographs it must not be mistaken for an avulsion fracture; conversely, a genuine os peroneum fracture (painful os peroneum syndrome) is a differential for lateral midfoot pain.

Injury to the tendon. Because the tendon is intimate with the plantar-lateral cuboid, plantar and lateral cuboid avulsion and crush fractures can lacerate, entrap or dislocate peroneus longus, or fracture the os peroneum. That is an overlooked cause of persistent lateral-column pain and weak eversion after apparent bony union.

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At surgery. In the lateral (Ollier-type or longitudinal) approach for cuboid ORIF, the peroneus longus and brevis tendons and the sural nerve overlie the field and must be identified and retracted. Hardware placed on the plantar-lateral surface can irritate the tendon.

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Foot compartment syndrome is the limb-threatening companion of the crush cuboid, and formal assessment for it is recommended in exactly these high-energy patterns. A crush or nutcracker cuboid rarely occurs alone, so every high-energy midfoot injury is screened for it.

Why it happens. High-energy nutcracker and Chopart crush patterns (Fenton Type 5, and Type 4 with Lisfranc disruption) transmit large compressive and shearing loads across the midfoot. The result is marked oedema and bleeding within the osseofascial compartments of the foot, classically described as nine to ten, including the deep calcaneal compartment that communicates with the deep posterior compartment of the leg. The risk is greatest with delayed presentation, associated Lisfranc or tarsometatarsal disruption, and polytrauma.

Diagnosis. Pain out of proportion, a tensely swollen foot and pain on passive extension of the toes are the key clinical signs; pulses and capillary refill are unreliable and typically preserved. Compartment pressures support the diagnosis when the difference between diastolic blood pressure and compartment pressure (delta-p) falls to fewer than 30 mmHg, equivalently an absolute pressure within roughly 30 mmHg of diastolic.

Treatment. Emergent foot fasciotomy, commonly through two dorsal incisions over the second and fourth intermetatarsal spaces, with a medial incision added to release the calcaneal and deep compartments if pressures remain elevated.

The cost of missing it. Ischaemic contracture with claw-toe deformity, intrinsic muscle fibrosis, chronic pain and sensory loss. That is a far worse outcome than the fracture itself, and it outweighs any benefit from a perfect cuboid reduction.

What the literature contains. There is no comparative outcome study of cuboid fracture, and no series large enough to give a success rate for any treatment arm. Percentages quoted for "cuboid fracture outcome" in review articles and algorithms are conventions, not measurements. The published figures, in full, are these:

Read the pattern, not the percentage. Every source agrees on the same gradient: an extra-articular cuboid fracture does well, an intra-articular one does less well, and involvement of the midtarsal joint or loss of lateral column length is what turns a nuisance injury into a poor foot. That gradient is the prognostic information worth giving a patient. The denominators behind it are 6, 11, 2 and 3, and Ruffing's children were followed for a mean of nine years.

Long-term shortening. Progression of lateral column shortening is conventionally quoted at 10-15% with proper treatment and 20-30% without; impaction, displacement and delayed treatment are the risk factors. These are teaching figures, not measurements, and the table above shows why: no cuboid cohort reports shortening rates by treatment arm.

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Global Epidemiology

• Cuboid fractures account for under 1% of all foot fractures; isolated cuboid fractures are rarer still, as most occur within a midtarsal (Chopart) or tarsometatarsal injury.
• In the largest series (Fenton 2016, n=192), capsular avulsion (Type 1) made up nearly half of all cuboid fractures, while true crush "nutcracker" patterns were a minority (~14%).
• Paediatric distribution differs - extra-articular body fractures predominate and grafting is rarely required (Ruffing 2019).

Guideline and Society Positions (side by side)

Note: there is no dedicated high-level guideline specific to cuboid fractures. Practice is extrapolated from midfoot/Chopart injury principles. No national joint registry captures cuboid fracture fixation (registries track arthroplasty, not midfoot trauma).

High- vs Limited-Resource Practice

The evidence base is limited to small retrospective series and case reports, so several questions remain genuinely unresolved: