Both Column Acetabular Fractures

One pattern within a family. Both-column is the commonest of Letournel's associated patterns, and it only means anything against the others - the full classification, the two Judet views and the operative approaches are on acetabular fractures. What makes this pattern distinct is that no part of the articular surface stays attached to the intact ilium, which is why it alone can show secondary congruence and be treated non-operatively in a patient who could not survive the alternative. The injury it travels with is hip dislocation, it sits within the wider spectrum of pelvic ring injuries, the nerve at risk posteriorly is the sciatic, the complication that most often spoils an otherwise good reduction is heterotopic ossification, and when the acetabulum is ultimately reconstructed the defect is graded by Paprosky.

The definition. Both the anterior and the posterior column are completely fractured and the fracture lines run out above the dome, so no fragment of articular surface is left attached to the intact ilium. The whole acetabulum floats below an ilium that is still joined to the sacrum, and that intact ilium sitting above the detached columns is the bone that throws the spur sign. A transverse fracture keeps some of the dome attached above its fracture line, and has no spur.

How common. Both-column accounts for 20-25% of all acetabular fractures. It is a complex injury and needs expert management.

Mechanism. High-energy trauma driving an axial load through the femoral head, which transmits the force to both columns.

Who. The age distribution is bimodal. Young patients, with a male predominance, break the acetabulum in high-energy trauma; older patients break the same bone in lower-energy injuries through osteoporotic bone.

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The two-column model. The acetabulum is suspended between two columns of bone, and the classification of every acetabular fracture is built on which of them is broken.

The anterior (iliopubic) column extends from the iliac crest to the symphysis and takes in the anterior part of the iliac wing, the anterior wall and the pubic ramus. It forms the anterior half of the acetabular dome.

The posterior (ilioischial) column extends from the greater sciatic notch to the ischial tuberosity and takes in the notch, the posterior wall and the tuberosity. It forms the posterior half of the dome.

Each column has a line on the radiograph. The iliopectineal line runs from the iliac crest to the pubis and represents the anterior column; the ilioischial line runs from the greater sciatic notch to the ischium and represents the posterior column. Break a column and its line breaks with it.

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Where it sits in Letournel. The classification has ten patterns: five elementary and five associated. The elementary five are the anterior wall, the anterior column (running from iliac crest to pubis), the posterior wall (the most common elementary pattern), the posterior column (the ilioischial line), and the transverse fracture, which divides the acetabulum into superior and inferior halves. The associated five combine them:

• T-shaped - a transverse fracture with a vertical component
• Posterior column plus posterior wall - a common combination
• Transverse plus posterior wall - additional instability
• Anterior column or wall plus posterior hemitransverse - a complex associated pattern
• Both column - the pattern this topic covers

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Subtypes worth naming. Where the fracture exits the ilium decides which approach reaches it:

• High both column - the fracture exits through the iliac crest
• Low both column - it exits through the sciatic notch
• With a posterior wall component - additional instability, and it must be looked for

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Telling it from its neighbours. Four other patterns are mistaken for it, and each is separated by one finding.

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How they arrive. The mechanism is high-energy and the patient is a trauma patient first, so the assessment is an ATLS one: polytrauma is common, an associated pelvic ring injury is possible, and the same leg may carry other injuries. The mechanisms that produce this fracture:

• Motor vehicle accident, classically a dashboard injury
• Motorcycle accident
• Fall from height
• Pedestrian struck
• Sports - skiing, equestrian

Force transmission. The load passes axially through the femoral head into both columns, and the position of the hip at impact determines which pattern results.

The hip itself. If the head has dislocated the limb lies shortened and externally rotated. Otherwise the findings are pain on hip motion, inability to bear weight, and tenderness over the hip and pelvis.

The examination that has to be written down. Motor function by root level:

• Hip flexion (L1-2)
• Knee extension (L3-4)
• Ankle dorsiflexion (L4-5)
• Great toe extension (L5) - most vulnerable
• Ankle plantarflexion (S1)

Sensation by dermatome: lateral thigh (L2), medial leg (L4), dorsum of the foot (L5) and lateral foot (S1).

Injuries that travel with it. Femoral head fracture (Pipkin), femoral neck fracture, hip dislocation, ipsilateral knee injuries from the dashboard, and contralateral injuries.

The Judet series. Three films: an AP pelvis and the two 45 degree obliques. Each answers a different question, and the pattern is not called from one of them alone.

• AP pelvis - both the iliopectineal and the ilioischial line are disrupted; assess roof involvement and the position of the femoral head
• Obturator oblique (45 degrees) - the key view. The spur sign is visible here and nowhere else, with the anterior column in profile and the posterior wall en face
• Iliac oblique (45 degrees) - the posterior column in profile, the anterior wall en face, and the greater sciatic notch

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CT. Essential for surgical planning, taken as 2mm axial cuts through the acetabulum with coronal and sagittal reformats. It is read for the extent of the fracture in each column, articular congruence, the integrity of the femoral head, intra-articular fragments and marginal impaction.

The 3D reconstruction demonstrates the disruption of both columns and makes the floating acetabulum obvious. It is the study the operation is planned from, and the one the patient and the team can be shown.

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Medialisation. When the quadrilateral plate is pushed medially the femoral head follows it, and medialisation of the head is the finding that turns an argument about surgery into a decision.

Assessing secondary congruence on CT. The measurements that decide whether the floating fragments have come to lie acceptably are the roof arc measurements, the articular step-off, the size of any gap, and the overall congruence of the surface against the head.

Roof arc angles (Matta) and the CT subchondral arc. The roof arc angles quantify whether the weight-bearing dome is intact. Each is measured from the geometric centre of the acetabulum between a vertical line and a line to the fracture exit through the roof, on the three plain views:

• Medial roof arc - on the AP view
• Anterior roof arc - on the obturator oblique view
• Posterior roof arc - on the iliac oblique view

If all three arcs exceed ~45 degrees, the superior weight-bearing dome is intact and the fracture may be managed non-operatively. The CT equivalent is the subchondral (10 mm) arc rule: if the fracture spares the cranial 10 mm of subchondral bone on the top axial cuts, the dome is preserved.

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Secondary congruence. Because the entire acetabulum is detached, the femoral head can act as a mould and push the fragments into acceptable alignment during weight-bearing, creating a functional weight-bearing surface despite the fracture. That is why the phenomenon belongs to this pattern alone, and it is more common in elderly patients with comminuted fractures.

The decision turns on two questions: whether secondary congruence is present on CT, and what this patient needs from the hip. A displaced fracture in a young patient is reconstructed; an elderly patient with a congruent joint and comorbidities may be better served by never being anaesthetised.

Non-OperativeOperativeDecision Algorithm

Who is treated without an operation. The candidate has a congruent joint or cannot survive the alternative:

• Secondary congruence present, with the femoral head moulding the fragments into alignment
• Elderly, low-demand patient with an acceptable articular surface
• Medical comorbidities precluding major surgery
• Roof arc measurements greater than 45 degrees in all planes
• Minimal displacement with acceptable articular congruence

A note on the roof arcs. They appear in these criteria and in the algorithm because they are the general acetabular rule, but in a both-column fracture no roof stays attached to the axial skeleton for them to measure. Secondary congruence is the assessment that actually decides.

The protocol. Skeletal traction for 2-4 weeks, then progressive mobilisation, with weight-bearing restrictions maintained for 6-12 weeks. Serial radiographs monitor the alignment, and losing it converts the plan to surgery.

Indications. Any one of these:

• Displaced fracture in a young, active patient
• Loss of secondary congruence on CT assessment
• Roof arc less than 45 degrees
• Articular step-off greater than 2mm
• Associated femoral head injury requiring open treatment
• Failed conservative treatment with loss of alignment

Timing. Ideally within 3-7 days of injury, which allows the swelling to settle, and it must be done within 14-21 days before callus forms. Beyond 3 weeks the reduction becomes significantly more difficult. Traction may be needed while the patient waits.

Choosing the approach. Selection is based on which column predominates and on the fracture configuration: an anterior-column-predominant fracture is approached through the ilioinguinal, a posterior-column-predominant one through the Kocher-Langenbeck, and combined approaches are frequently required in this pattern. That last statement deserves qualifying - in Matta's 262 displaced fractures the vast majority were managed through a single approach and only 4 hips needed the ilioinguinal and the Kocher-Langenbeck together, so combined exposure is a decision made on the fracture rather than a reflex of the diagnosis.

Algorithm

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Step 1 - assess secondary congruence. CT to see whether the femoral head has moulded the fragments into alignment. If it has, and the roof is acceptable, non-operative care is on the table for an elderly patient.

Step 2 - weigh the patient. A young, active patient generally requires anatomic reduction; a low-demand elderly patient may tolerate some incongruity. Medical fitness for major surgery has to be assessed honestly.

Step 3 - plan the approach. Determine which column is more displaced and make that the primary approach; plan a combined approach if both are significantly displaced; and consider timing and staging against the patient's condition.

Nerve injury. The sciatic nerve is at risk from the injury and from the exposure, which is why the deficit is documented before anyone operates.

Vascular injury. The corona mortis with the ilioinguinal approach, the superior gluteal artery with the posterior approach, and the external iliac vessels in the middle window.

Thromboembolism. DVT risk is very high and pulmonary embolism is a significant concern, so prophylaxis is essential.

Infection. Surgical site infection is more common with the extensive approaches these fractures require, and careful handling of the skin matters.

Post-traumatic arthritis is the most common long-term complication and its likelihood follows the quality of the reduction. A hip replacement may be needed.

Heterotopic ossification is common after extensive approaches and may limit range of motion. Prophylaxis is indometacin or radiation.

Avascular necrosis of the femoral head follows an associated posterior dislocation, particularly where reduction was delayed, and carries a poor prognosis.

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Reduction quality decides the result. It is the strongest predictor of outcome there is, and an anatomic reduction of less than 1mm achieves good to excellent results in 80-90%. Combined approaches allow adequate access for most patterns.

What makes it worse. An articular step-off greater than 3mm strongly predicts post-traumatic arthritis, an associated femoral head injury worsens the prognosis, and a reduction compromised by delay carries its penalty into the result.

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Global Epidemiology

According to large registry data, the epidemiology of acetabular fractures is shifting worldwide from high-energy injuries in young men towards low-energy falls in older adults. In the German Pelvic Multicentre registry of 2,853 unilateral acetabular fractures, the mean age was 61.5 years and rising, with a parallel shift from simple patterns to complex fractures involving the anterior column. Both-column fractures are the single most common associated pattern, accounting for roughly a third of operatively treated acetabular fractures in the Matta series.

Guideline & Society Positions (Side by Side)

The "Gull Sign" in Geriatric Acetabular Fractures

In older patients (typically an anterior-column / anterior-column-posterior-hemitransverse pattern), superomedial dome impaction produces a characteristic radiographic "gull sign" (a seagull-wing appearance of the impacted roof). It is an important predictor of poor ORIF outcome — the impacted, osteoporotic articular surface is difficult to reconstruct durably — and is one of the features (alongside femoral-head impaction, marginal/articular comminution and large-area dome impaction) that favours acute total hip arthroplasty / fix-and-replace over attempted reconstruction in the frail elderly.

Registry Evidence

Joint and trauma registries (the German Pelvic Registry, and for the arthroplasty endpoint the NJR of England and Wales, AOANJRR in Australia, AJRR in the USA and the Swedish/Nordic registries) consistently show two themes: reduction quality and outcome improve with surgeon and centre volume, and a growing proportion of older patients are managed with primary or salvage total hip arthroplasty rather than ORIF.

Global Practice Variation

• High-resource settings: routine CT with 3D reconstruction, anterior intrapelvic (Stoppa-type) approaches, and increasing fix-and-replace/acute THA in the elderly.
• Limited-resource settings: greater reliance on traction and non-operative management exploiting secondary congruence, and on single-approach plating where combined exposures or arthroplasty are not feasible.
• Universal principles: early specialist referral, meticulous documentation of sciatic nerve function, thromboprophylaxis, and heterotopic ossification prophylaxis (indometacin or single-dose radiotherapy) after extensile posterior exposures.