Acetabular Fracture ORIF - Ilioinguinal Approach

Indications. The ilioinguinal approach is the workhorse ANTERIOR exposure for displaced acetabular fractures, used for: - Anterior column fracture with an articular step-off greater than 2mm or a gap greater than 5mm

• Anterior wall fracture that is displaced with hip instability
• Anterior column plus posterior hemitransverse fracture - the classic pattern for this approach
• Both-column fracture when anterior displacement predominates
• Transverse fracture when the anterior component is significantly displaced (a less common indication), and transverse plus posterior wall when a combined approach is planned with the anterior component addressed first Radiographic criteria that tip the decision toward fixation. Articular step-off greater than 2mm on CT, displacement greater than 5mm at the pelvic brim, loss of secondary congruence in both-column patterns, and a medial roof arc angle less than 45 degrees. Relative indications include the polytrauma patient needing staged fixation (anterior first), an associated pelvic ring injury requiring symphyseal or ramus fixation, failed closed reduction with persistent anterior displacement, and the need to decompress or directly visualise the quadrilateral plate. Contraindications. Absolute: active pelvic sepsis, previous ilioinguinal surgery with extensive scarring, severe peripheral vascular disease precluding vessel mobilisation, or medical unfitness for a 3-4 hour procedure. Relative: morbid obesity (BMI greater than 40 - consider percutaneous techniques), previous mesh inguinal hernia repair (requires modification), a posterior wall fracture as the primary pathology (use Kocher-Langenbeck), an isolated posterior column fracture, or delayed presentation beyond three weeks (consider an extensile approach).

Pre-operative assessment. Establish the mechanism (high-energy motor-vehicle collision or fall from height; in the elderly a low-energy fall may behave as a hip-fracture-equivalent) and hunt for associated head, chest, abdominal and spinal injuries - polytrauma is common. Document pre-injury mobility and comorbidities (DVT risk, bleeding disorders, anticoagulation). Examine and document the femoral, sciatic and obturator nerves before surgery - the approach places the femoral nerve at risk and a documented baseline is essential. Check specifically for a Morel-Lavallee degloving lesion (which delays surgery), bladder or bowel injury, and the associated pelvic ring. Imaging. Plain films are the Judet series plus the inlet and outlet; CT with 3D reconstruction defines the articular injury.

Alternatives to discuss are non-operative management (bed rest 6-8 weeks - with the risks of malunion, arthritis and prolonged morbidity), percutaneous fixation for selected minimally displaced patterns, and an alternative approach (modified Stoppa, Kocher-Langenbeck, or a combined anterior-posterior approach). Equipment.

Anaesthesia and positioning. General anaesthesia is mandatory - the prolonged procedure (3-4 hours) precludes regional alone, and muscle relaxation is essential for reduction. Adjuncts: tranexamic acid 1g IV at induction repeated at 3 hours, a cell saver, hypotensive anaesthesia (MAP 60-70) if tolerated, and forced-air warming. Avoid nitrous oxide (bowel distension impairs access); give cefazolin 2g IV within 60 minutes of incision and repeat every 4 hours or after 1.5L blood loss. Position the patient supine on a radiolucent table with a Foley catheter (to decompress the bladder away from the medial field), the arms on boards or tucked, and slight hip flexion (10-20 degrees) to relax the iliopsoas. Confirm fluoroscopy can deliver AP, inlet, outlet and both Judet obliques before draping.

The goal is to expose the entire anterior column and pelvic brim from the SI joint to the symphysis through three anatomically safe windows, protect the external iliac vessels, femoral nerve and LFCN throughout, ligate the corona mortis prophylactically, reduce the fracture from proximal to distal, and apply a contoured pelvic brim plate. The exposure - the three windows - is the heart of the operation and is laid out as the first operative steps below.

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Rehabilitation and weight-bearing progression | Phase | Timing | Weight-bearing and mobilisation | Focus | |-------|--------|--------------------------------|-------| | 1 | Day 0-2 | HDU monitoring; toe-touch only once mobile | Neurovascular checks 2-hourly; DVT and HO prophylaxis | | 2 | Weeks 1-6 | Toe-touch weight-bearing with a frame or crutches | Hip ROM (avoid forced flexion); wound review at 48h | | 3 | Weeks 6-12 | Progress to partial, then full weight-bearing by ~12 weeks if radiographically healing | Strengthening, gait retraining | | 4 | Months 3-12 | Full activity as the fracture heals | Return to sedentary work 3-6 months; manual work 6-12 months | Immediate post-operative regimen. Monitor on HDU if there has been significant blood loss; perform neurovascular observations every 2 hours for 24 hours and watch for abdominal compartment syndrome if there is a large retroperitoneal haematoma (urine output minimum 0.5ml/kg/hour). Start LMWH (enoxaparin 40mg daily) from day 1, heterotopic ossification prophylaxis with indomethacin 25mg TDS for 6 weeks (or a single 700cGy fraction within 72 hours if indomethacin is contraindicated), and analgesia via PCA then oral targeting pain less than 4/10. Remove drains when output is less than 30ml per 8-hour shift (typically 48-72 hours). Obtain the post-operative CT within 48 hours and review with X-rays (AP pelvis and Judet views) at 6 weeks, 3 months, 6 months and 1 year. Complications - recognition, prevention, management

Mechanism and epidemiology. Acetabular fractures are high-energy injuries - most commonly motor-vehicle collisions and falls from height - and frequently occur in the polytrauma patient with associated head, chest, abdominal and spinal injuries. In the elderly, a low-energy fall may produce an acetabular fracture as a fragility (hip-fracture-equivalent) injury, often through a protrusio pattern. Because the approach crosses the groin, the procedure is prolonged (3-4 hours) and typical blood loss is 500-2000ml, these patients need thorough pre-injury functional assessment, comorbidity optimisation and multidisciplinary planning. Classification drives the approach. Acetabular fractures are classified by the Letournel-Judet system into elementary patterns (anterior wall, anterior column, posterior wall, posterior column, transverse) and associated patterns (posterior column plus posterior wall, transverse plus posterior wall, T-shaped, anterior column plus posterior hemitransverse, and both-column). The ilioinguinal is the workhorse ANTERIOR approach, selected for the anterior column, anterior wall, anterior column plus posterior hemitransverse, and both-column fractures in which anterior displacement predominates. Posterior patterns are addressed through the Kocher-Langenbeck approach, and transverse patterns are approach-selected by which column is most displaced - exactly the reasoning Letournel used when designing the three-window exposure. Key evidence. Letournel established that anatomic open reduction is the treatment of choice for displaced acetabular fractures and that the quality of articular congruence is the single most important determinant of outcome. Matta (1996) reported anatomic reduction in 71% of 262 operatively treated fractures, with excellent or good clinical results in 76% - rates that fell with increasing fracture complexity, patient age and delay to surgery. The Giannoudis meta-analysis (2005) of 3,670 fractures confirmed post-traumatic arthritis in roughly 20% (the commonest late complication), heterotopic ossification and AVN each less than 10%, and excellent or good outcomes in 75-80% at a mean of 5 years. This consistent message - operate early, through the least extensile approach that achieves anatomic reduction, and refer to a specialist pelvic unit - underpins modern practice.