Define Acetabular Fractures. Describe its classification, clinical features, investigations and management.

Definition & Anatomy

An acetabular fracture involves the socket of the hip joint. It is an intra-articular fracture, usually from high-energy trauma transmitted through the femoral head (a dashboard injury with the hip flexed, or a fall). The acetabulum is conceptualised as two columns — the anterior (iliopubic) and posterior (ilioischial) columns, joined by the sciatic-buttress ‘inverted Y’ — the basis of the Judet–Letournel classification.

The acetabulum as anterior and posterior columns joined by the sciatic buttress — the anatomical basis of the Judet–Letournel classification.

Mechanism & Associated Injuries

The pattern depends on the position of the femoral head at impact and the direction of force. A dashboard injury with the hip flexed and adducted drives the head posteriorly, producing a posterior wall fracture ± posterior dislocation; force through an abducted hip tends to injure the anterior structures. Because of the high energy, look for associated ipsilateral knee, femoral shaft and neck injuries, and pelvic and abdominal trauma.

Classification

The Judet–Letournel classification divides fractures into elementary (posterior wall, posterior column, anterior wall, anterior column, transverse) and associated patterns (e.g. Both-column, T-shaped, transverse + posterior wall). Posterior wall fractures are the commonest and are frequently associated with posterior hip dislocation.

Clinical Features

Hip pain and inability to bear weight after high-energy trauma. Because many acetabular fractures accompany a hip dislocation, assess the limb position and — crucially — the sciatic nerve (especially its peroneal division) in posterior injuries. Screen for the associated pelvic, knee (dashboard) and abdominal injuries.

Investigations

AP pelvis with Judet (oblique) views and, definitively, a CT scan with reconstructions to define the columns, articular comminution, marginal impaction, and any intra-articular fragments or femoral head injury.

Management

The goal is a congruent, stable, pain-free hip. Undisplaced fractures, or those with a congruent joint and an intact weight-bearing dome, are treated non-operatively with protected weight-bearing. Displaced fractures with articular incongruity, an unstable joint or an intra-articular fragment require open reduction and internal fixation (anatomical reduction of the joint surface via the appropriate column approach). In the elderly with severe comminution, acute total hip replacement (sometimes with fixation) is an option.

Complications

Post-traumatic osteoarthritis (the main long-term problem, from articular damage or incongruity), avascular necrosis of the femoral head (especially after dislocation), sciatic nerve injury, heterotopic ossification, and infection after surgery.

• Intra-articular, high-energy; conceptualised as anterior + posterior columns (Judet–Letournel).
• Posterior wall is commonest and often accompanies posterior hip dislocation.
• Reduce a hip dislocation urgently; check the sciatic (peroneal) nerve.
• CT defines the pattern; congruent joint → non-operative, displaced/incongruent → ORIF.
• Main sequelae: post-traumatic OA and femoral head AVN.