Kocher-Langenbeck Approach to the Acetabulum

What it exposes. The Kocher-Langenbeck is the consensus posterior approach to the acetabulum, giving direct access to the posterior wall, the posterior column from the greater sciatic notch to the ischial tuberosity, and the retroacetabular surface of the innominate bone. It is the workhorse exposure for posterior wall fractures (the commonest acetabular pattern, about 40 percent of acetabular fractures), posterior column fractures, and the posterior component of transverse and T-type fractures. Why posterior. Posterior wall and posterior column injuries are not reachable from the anterior (ilioinguinal/Stoppa) approaches, which cannot visualise the retroacetabular surface or control the sciatic nerve. The Kocher-Langenbeck also allows the hip to be taken through a range of motion to test stability and gives simultaneous access to the femoral head when an associated dislocation is reduced. Position. Either lateral or prone is acceptable - position does not change the iatrogenic nerve-palsy rate (Schaffer 2024). Prone aids reduction of transverse and T-type patterns; lateral allows hip flexion to relax the sciatic nerve. Image intensification must be free to obtain Judet views.

Timing and referral. Reduce an associated hip dislocation urgently - delay greater than 12 hours worsens outcome and raises the risk of femoral-head osteonecrosis (Moed 2002). Definitive fixation is generally undertaken within about 5 to 10 days once the patient is optimised, balancing soft-tissue recovery against the increasing difficulty of late reduction. Displaced acetabular fractures are best managed in high-volume pelvic and acetabular units; outcomes correlate with surgeon and centre volume, and the iatrogenic sciatic-palsy rate is surgeon-dependent (Schaffer 2024) - a strong argument for centralised care consistent with major-trauma network pathways.

Work from skin to capsule through a single posterior incision. The whole point of the approach is to reach the posterior wall and column while keeping the sciatic nerve identified, relaxed and protected at every step.

View larger

Structures at risk and complications

Sciatic nerve palsy in detail. This is the most feared complication of the approach. The common peroneal division is more vulnerable than the tibial division (more lateral, tethered, fewer protective septa), so the deficit is typically a foot drop with sensory loss over the dorsum and lateral foot. Independent risk factors for an iatrogenic palsy are the individual surgeon and a transverse fracture pattern; patient position (prone versus lateral) does NOT change the risk (Schaffer 2024). Most incomplete palsies recover substantially over 6 to 18 months; complete palsies recover less reliably. Baseline EMG/NCS at about 3 to 6 weeks, an early foot-drop orthosis, and consideration of exploration if a complete palsy has a correctable cause (entrapped fragment, hardware) or shows no recovery by 3 to 6 months. Sciatic nerve protection strategy: 1. Identify the nerve proximally, before rotator release. 2. Flex the hip and knee to relax the nerve. 3. Use intermittent retraction - release every 15 minutes. 4. Place retractors deep to the nerve (between nerve and bone). 5. Use SSEP/EMG monitoring where available. 6. Repair the external rotators to cushion the nerve from hardware. 7. Use gentle surgical technique throughout.

Femoral-head assessment. Posterior wall fractures are often associated with hip dislocation - assess the femoral head for impaction injury (indentation fracture), chondral injury and loose bodies. Femoral-head impaction greater than 4 mm may need bone grafting. Extensile options. The standard incision extends proximally toward the posterior superior iliac spine or distally along the femoral shaft. A trochanteric osteotomy or trochanteric flip improves access to the superior dome and the anterior column but adds nonunion and HO risk, so it is reserved for selected complex patterns. For both-column fractures with anterior and posterior displacement, a staged two-incision strategy (Kocher-Langenbeck for the posterior column, then ilioinguinal or modified Stoppa for the anterior column) is usually preferred over a single extended iliofemoral approach. Closure and rotator repair. Repairing the external rotators interposes a soft-tissue layer between the sciatic nerve and any posterior hardware, restores hip external-rotation strength and posterior soft-tissue tension, and re-establishes the medial femoral circumflex contribution carried by the conjoint tendon. Repair is standard of care on anatomical and biological grounds; a specific palsy-reduction percentage is not established by high-level evidence.

Layered closure. Repair the posterior capsule with absorbable suture (No. 1 Vicryl) if sufficient tissue remains (T-capsulorrhaphy where possible), approximate the gluteus maximus fascia (2-0 Vicryl), Scarpa's fascia (3-0 Vicryl) and skin (staples or subcuticular). Leave a deep subfascial drain (15-19 Fr round), removed at 24-48 hours.

Hip precautions (posterior wall fracture):

• Avoid flexion greater than 90 degrees for 6 weeks.
• Avoid adduction past midline for 6 weeks.
• Avoid internal rotation for 6 weeks.
• These positions stress the posterior wall repair. Long-term outcomes:
• Good-to-excellent results in roughly 75-80 percent with anatomic reduction (Matta 1996: 76 percent overall; Moed 2002 for isolated posterior wall: about 80 percent).
• Quality of articular reduction is the strongest modifiable predictor; femoral-head injury, age 55 or over, and delay greater than 12 hours to reduce an associated dislocation worsen outcome.
• Post-traumatic arthritis is the commonest reason for later total hip arthroplasty (THA in about 6 percent within follow-up in Matta's series).
• Heterotopic ossification is common but frequently asymptomatic.
• Most incomplete sciatic nerve palsies recover substantially over 6-18 months; complete palsies recover less reliably.

• Posterior wall ORIF — the principal procedure (lag screws plus a buttress/spring plate).
• Posterior column ORIF — contoured reconstruction plating from the sciatic notch to the ischium.
• Transverse and T-type fractures — reduction and fixation of the posterior component.
• Combined posterior column + wall and selected both-column patterns (often staged with an anterior approach). Fixation strategies for the posterior wall

Reduction target. Aim for an anatomic reduction with an articular step or gap of less than 1 mm on all three intraoperative views. Matta defined residual displacement of 1 mm or less as "anatomic"; outcomes deteriorate progressively beyond this. Fluoroscopic assessment (Judet views):

• Obturator oblique — the best view for the posterior wall and posterior rim; also shows the anterior column.
• AP pelvis — overall joint congruence (roof, teardrop, ilioischial line).
• Iliac oblique — the best view for the posterior column and the anterior wall. Screw safety. Confirm that no screw has breached the joint, using multiple fluoroscopic projections and the obturator-oblique "in-out-in" technique. Intra-articular screws are a common avoidable cause of early failure. Stability testing:
• After fixation, take the hip through a controlled range of motion under image intensification.
• Assess for posterior subluxation, particularly in flexion-adduction-internal rotation.
• If unstable despite wall fixation, reassess the fixation and consider supplementary buttressing.
• Posterior-wall size alone (the historical "40 percent rule") is an unreliable predictor of stability - dynamic stress examination under anaesthesia is the most reliable test, and fractures exiting near the acetabular dome behave less stably regardless of fragment size.

Guidelines, registries and global practice Referral and centralisation. Internationally, displaced acetabular fractures are best managed in high-volume pelvic and acetabular units. Outcomes correlate with surgeon and centre volume, and the iatrogenic sciatic-palsy rate is surgeon-dependent (Schaffer 2024) - a strong argument for centralised care, consistent with major-trauma network pathways elsewhere. Timing. Reduce an associated hip dislocation urgently (delay greater than 12 hours worsens outcome and raises AVN risk - Moed 2002). Definitive fixation is generally undertaken within about 5-10 days once the patient is optimised, balancing soft-tissue recovery against the increasing difficulty of late reduction. Classification and approach selection. The Letournel-Judet classification is the universal framework; the Kocher-Langenbeck is the consensus posterior approach across AO Foundation teaching and the advanced orthopaedic practice (Tr and Orth), advanced orthopaedic practice and advanced orthopaedic practice curricula. HO prophylaxis - genuine practice variation. Both indomethacin and single-dose radiation are evidence-based and of equivalent efficacy in RCTs (Burd 2001; Moore 1998). Practice differs by centre and resource setting - radiation is preferred when an NSAID is contraindicated (for example a concurrent long-bone fracture, given indomethacin's nonunion risk), while indomethacin is far cheaper and more widely available. VTE prophylaxis. Combined mechanical and pharmacological prophylaxis (low-molecular-weight heparin or a direct oral anticoagulant) is standard in major-trauma guidance worldwide; the agent and duration follow local protocols and bleeding-risk assessment. Intraoperative monitoring. SSEP and/or continuous EMG monitoring of the sciatic nerve is used selectively in high-risk cases where available; it is not universally mandated and its outcome benefit is not firmly established.