Acetabular fractures

The acetabulum sits in an inverted Y of two columns: the anterior (iliopectineal) and posterior (ilioischial). Letournel described five elementary and five associated patterns; recognising them on the AP and Judet views guides the approach.

Mechanism

Force transmitted through the femoral head: dashboard injury (posterior wall, often with hip dislocation); falls on the side in the elderly (anterior column, quadrilateral plate).

Clinical findings

• Check the sciatic nerve (posterior wall fractures with dislocation). Reduce a dislocated hip urgently.

Imaging

• AP pelvis.
• Judet views: obturator oblique (anterior column, posterior wall) and iliac oblique (posterior column, anterior wall).
• CT with 3D reconstructions is the standard for classification (Letournel) and planning.

• AP pelvis, Judet views (obturator and iliac oblique) and CT with 3D reconstructions. Six lines on the AP: iliopectineal, ilioischial, teardrop, roof, anterior and posterior wall.

Classification

Elementary

Posterior wall, posterior column, anterior wall, anterior column, transverse.

Associated

Posterior column + wall, transverse + posterior wall, T-shaped, anterior column + posterior hemitransverse, both columns ("spur sign").

AO/OTA 62

62A one column/wall, 62B transverse-type (part of the roof attached to the ilium), 62C both columns (articular surface detached from the ilium).

Types shown in 3D

Posterior wall

The most common: dashboard injury with posterior hip dislocation. Check the sciatic nerve; fix through a Kocher–Langenbeck approach.

Posterior column

The ischial part separates from the sciatic notch down through the joint into the obturator ring; the head follows it medially.

Anterior column

Typical of falls on the side in the elderly; the anterior part of the joint and the superior ramus separate. Anterior approach (ilioinguinal or modified Stoppa).

Transverse

One line across the acetabulum splits the innominate bone into an upper (iliac) and a lower (ischiopubic) half; the head can protrude centrally.

Both columns

No part of the joint stays attached to the intact ilium ("floating acetabulum", spur sign on the obturator oblique view). Secondary congruence can allow non-operative care in the elderly.

Treatment

Non-operative

Displacement < 2 mm, roof arcs intact, stable hip, or a both-column fracture with secondary congruence: protected weight bearing 6–8 weeks.

Operative

Displaced fractures in fit patients: anatomical reduction and plates/screws through the Kocher–Langenbeck (posterior) or ilioinguinal / modified Stoppa (anterior) approaches, within about 2 weeks. Elderly with poor bone and femoral head impaction: consider acute total hip arthroplasty with fixation.

Aftercare

Toe-touch weight bearing 8–12 weeks.

Complications

• Post-traumatic arthritis
• Heterotopic ossification (posterior approach)
• Sciatic nerve injury
• Avascular necrosis of the femoral head
• Thromboembolism