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Transverse Acetabular Fracture ORIF

Surgical technique guide for Transverse Acetabular Fracture ORIF - FRCS exam preparation

Core Procedure
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High-yield overview

Kocher-Langenbeck posterior approach (most common transverse pattern) | Letournel classification | Roof arc assessment (45 degrees, all 3 arcs) | Anterior column screws from posterior

Absolute Indications

  • Displaced transverse fracture with >2mm articular step or gap involving the weight-bearing dome
  • Incongruous hip joint (femoral head not concentric with intact dome)
  • Roof arc angle <45° on any view (medial/anterior/posterior) indicating dome involvement
  • Associated posterior wall fracture causing posterior instability
  • Open fracture
  • Irreducible fracture-dislocation or intra-articular fragment blocking reduction

Relative Indications

  • 2mm displacement in a young, active patient
  • Quadrilateral plate medialization causing hip incongruity
  • Associated T-type or posterior-wall component
  • Failed/unacceptable closed reduction in a low transverse pattern
  • Progressive sciatic nerve palsy after closed reduction (suggests entrapment)
Mnemonic

ROOF

Roof Arc Angle Thresholds (Matta 1986)

Mnemonic

LETOURNEL

Transverse Fracture Management Principles

Critical Danger Structures

Sciatic Nerve

Location: Crosses the posterior column ~20-30mm medial to the posterior acetabular rim. Protection: Position of safety is hip EXTENSION with knee FLEXION (~60-90°) to slacken the nerve; gentle retraction, palpate the nerve intermittently, limit continuous retraction. Hip flexion TENSIONS the nerve and should be avoided.

Superior Gluteal Bundle

Location: Exits ABOVE piriformis at greater sciatic notch (only structure above piriformis). At risk: Extended iliofemoral approach, retraction through greater sciatic notch.

External Iliac Vessels

Location: 30-40mm medial to pelvic brim in middle window. At risk: If anterior/combined approach needed for T-type or quadrilateral plate fixation.

Femoral Nerve

Location: Lateral to external iliac artery in iliopsoas groove. At risk: Anterior approach retraction. Protected by iliopsoas during surgery.

Surgical Anatomy

Letournel's Column Concept

The acetabulum is formed by two columns:

  • Anterior column: Anterior ilium → anterior wall → superior pubic ramus (forms "inverted Y")
  • Posterior column: Posterior ilium → posterior wall → ischium

Transverse fracture divides the acetabulum horizontally into:

  • Superior segment: Iliac wing + superior dome (attached to sacrum - STABLE)
  • Inferior segment: Ischiopubic segment (UNSTABLE - displaces)

Roof Arc Concept

The weight-bearing dome (superior acetabular articular surface) is the critical zone:

  • Roof arcs (Matta 1986): three angles (medial/anterior/posterior) quantify how much intact dome remains around the femoral-head centre
  • CT subchondral arc: the superior ~10mm of subchondral bone on the axial CT slices through the dome; an intact subchondral arc corroborates a spared dome
  • Fractures crossing the dome (transtectal) have the highest rates of post-traumatic arthritis
  • The roof-arc rule is only valid for fracture lines that pass through the articular surface (transverse, T-type, anterior/posterior column); it does NOT apply to posterior-wall or both-column fractures

Sciatic Nerve Anatomy

  • Exits the pelvis through the greater sciatic foramen, classically BELOW piriformis (Beaton-Anson type I in ~85-90%); variant anatomy (split nerve, division above/through piriformis) occurs in 10-15% and must be anticipated
  • Lies approximately 20-30mm medial to the posterior acetabular rim as it crosses the posterior column
  • Most commonly injured nerve in acetabular surgery; iatrogenic injury reported in roughly 2-10%, with the peroneal (common fibular) division most vulnerable to traction
  • Hip extension with knee flexion is the position that relaxes the nerve during retraction (the sciatic nerve crosses the hip and knee; knee flexion shortens its excursion)

Quadrilateral Plate

  • Thin medial wall of acetabulum
  • Separates hip joint from pelvis
  • Commonly displaces medially in transverse fractures
  • Medialization causes hip joint incongruity even with column reduction

Positioning and Preparation

Patient Position: Lateral decubitus or prone on a radiolucent table, affected side up, secured with a beanbag or pelvic posts. The leg is draped free so the limb can be positioned in hip extension with the knee flexed to protect the sciatic nerve during retraction.

Surgical Approach: Kocher-Langenbeck posterior approach (70% of transverse fractures). Extended iliofemoral only for complex T-types or when better anterior column visualization needed.

Incision: Curved incision from PSIS to greater trochanter to lateral thigh (15-20cm). Adequate length prevents excessive retraction.

Key Setup Points:

  • Ensure hip can flex/extend/rotate for reduction maneuvers
  • Test all fluoroscopy views BEFORE draping (AP, obturator oblique, iliac oblique)
  • Confirm radiolucent table positioning
  • Cell saver available for blood conservation

Operative Technique

Step 1: Preoperative Planning and CT Analysis

Study CT with 3D reconstruction systematically:

  • Fracture classification: Pure transverse vs transverse + posterior wall (30-40%) vs T-type
  • Fracture level: Transtectal, juxtatectal, or infratectal
  • Roof arc angles: Measure on AP and both obliques
  • Quadrilateral plate displacement: Assess medialization
  • Marginal impaction: Identify areas requiring elevation

Clinical Pearl

Letournel Principle: Most transverse fractures CAN be fixed from posterior Kocher-Langenbeck approach alone using anterior column screws directed from posterior. This avoids combined approach morbidity.

Step 2: Position and Prepare for Kocher-Langenbeck Approach

  • Lateral decubitus (or prone), affected side up, secured with a beanbag or posts
  • Keep the hip EXTENDED and the knee FLEXED - CRITICAL to slacken the sciatic nerve
  • Radiolucent table allowing AP, obturator oblique, iliac oblique views
  • Test ALL views before draping

Clinical Pearl

EXAM KEY: The sciatic nerve runs posterior to the hip and crosses the knee, so it is tensioned by hip flexion and relaxed by hip extension plus knee flexion - that is the protective position whenever the nerve is retracted. Prone positioning aids reduction of the posterior column and avoids posterior subluxation of the head; lateral decubitus is easier for imaging and limb manipulation.

Step 3: Make Kocher-Langenbeck Incision

  • Incision from PSIS to greater trochanter to lateral thigh (15-20cm curved)
  • Divide subcutaneous tissue
  • Split gluteus maximus bluntly in the line of its fibres (the distal split is limited to avoid the inferior gluteal neurovascular pedicle entering the deep surface)
  • Identify the sciatic nerve on the posterior surface of quadratus femoris / short rotators and protect it EARLY
  • A short incision forces excessive retraction and is a classic cause of traction nerve injury

Sciatic Nerve Protection

Identify the sciatic nerve BEFORE releasing the external rotators. Keep the hip extended and the knee flexed, relax retractors intermittently, and avoid monopolar cautery near the nerve. Continuous forceful retraction is the main driver of iatrogenic palsy.

Step 4: Release External Rotators

  • Detach piriformis and obturator internus (with the gemelli) ~10-15mm from their trochanteric insertions, leaving a tendinous cuff for repair
  • Preserve quadratus femoris: the deep branch of the medial femoral circumflex artery (MFCA) - the dominant blood supply to the femoral head - runs just deep/superior to QF, so QF is left intact to protect head perfusion
  • The obturator internus tendon is a key landmark: its bursa leads the finger safely to the greater and lesser sciatic notches, and it can be used to cushion a retractor protecting the sciatic nerve
  • Tag tendons with heavy non-absorbable suture for later anatomic repair
  • Capsulotomy is performed along the acetabular rim (not radially through the labral base) only as needed for joint inspection, preserving any remaining capsular blood supply

Clinical Pearl

EXAM KEY: Preserving quadratus femoris protects the deep branch of the MFCA and limits iatrogenic osteonecrosis. Anatomic short-rotator and capsular repair reduces postoperative posterior instability.

Step 5: Assess Fracture Pattern Through Posterior Exposure

  • Clear hematoma from fracture site and joint
  • Identify posterior column fracture line (greater sciatic notch to ischial tuberosity)
  • Visualize transverse fracture line across dome
  • Check for associated posterior wall fragments (30-40% of transverse)
  • Assess anterior column indirectly through greater sciatic notch
  • Identify any marginal impaction requiring elevation

Clinical Pearl

Column Anatomy: Superior segment = ilium + dome (STABLE). Inferior segment = ischium + pubis (UNSTABLE - displaces). Always reduce unstable to stable.

Step 6: Reduce Inferior Fragment to Superior Stable Reference

Reduction Sequence (critical principle):

  1. Superior iliac segment is stable (attached to sacrum) - this is the REFERENCE
  2. Inferior ischiopubic segment displaces - this must be REDUCED
  3. Insert ball spike pusher through greater sciatic notch to control superior fragment
  4. Place Schanz pin in ischial tuberosity for joystick manipulation of inferior fragment
  5. Apply pelvic reduction clamps (Farabeuf, Jungbluth) to compress fracture
  6. Reduce inferior TO superior, NOT vice versa

Clinical Pearl

EXAM KEY: Always reduce UNSTABLE fragment to STABLE reference. Working from stable to unstable is fundamental. Confirm reduction on fluoroscopy before clamping.

Step 7: Assess Articular Reduction

Direct Visualization:

  • Through posterior capsulotomy, directly visualize articular surface
  • Gentle hip rotation allows visualization of anterior and superior dome
  • Accept only <1mm articular step

Fluoroscopic Confirmation (ALL views mandatory):

  • AP pelvis: Overall alignment
  • Obturator oblique: Anterior column + posterior wall
  • Iliac oblique: Posterior column + anterior wall

Clinical Pearl

Judet Views: Obturator oblique shows what you CAN'T directly see from posterior (anterior column, posterior wall profile). Iliac oblique shows posterior column clearly.

Step 8: Provisional Fixation

  • Hold reduction with 2.0mm K-wires or provisional lag screws
  • Ensure reduction maintained on repeat fluoroscopy
  • If reduction lost with provisional fixation → reassess reduction technique
  • Do NOT proceed to plating without confirmed anatomic reduction

Step 9: Apply Posterior Column Plate

  • 3.5mm reconstruction plate contoured to posterior column
  • Position from greater sciatic notch posteriorly to ischial tuberosity inferiorly
  • Minimum 3 screws in superior segment (ilium)
  • Minimum 3 screws in inferior segment (ischium)
  • All screws bicortical for maximum purchase
  • Screws directed anteriorly, away from joint

Clinical Pearl

Plate Contouring: Pre-contour BEFORE final reduction or plate will displace fracture when tightened. Plate too anterior risks joint penetration.

Step 10: Place Anterior Column Lag Screws from Posterior

Letournel's Key Technique:

  • Insert lag screws from posterior column directed anteriorly into anterior column
  • Use 3.5mm or 4.5mm cortical screws
  • Entry point on posterior column
  • Trajectory toward pelvic brim/anterior column
  • Provides fixation of BOTH columns from single posterior approach
  • Check length on fluoroscopy - must NOT penetrate anterior cortex

Clinical Pearl

EXAM KEY: Anterior column screws from posterior is Letournel's major contribution. This allows single approach for most transverse fractures, avoiding combined approach morbidity.

Screw Trajectory

Use fluoroscopy on ALL views to confirm screw trajectory. Screws directed too medially risk iliac vessel injury. Too anteriorly risks penetration into soft tissues.

Step 11: Address Associated Posterior Wall (if present)

  • 30-40% of transverse fractures have associated posterior wall
  • Reduce wall fragments separately AFTER column fixation
  • Apply buttress plate (reconstruction or spring plate) for posterior wall
  • Multiple screws into stable posterior column
  • Assess hip stability - should be stable through ROM

Clinical Pearl

Fixation Sequence: Column MUST be fixed before wall. Wall fixation buttresses against stable column construct. Check posterior wall coverage >60% for stability.

Step 12: Address Quadrilateral Plate Medialization

If significant medialization visible on obturator oblique:

  • May need limited ilioinguinal medial window OR separate Stoppa approach
  • Infrapectineal buttress plating from medial prevents continued medialization
  • This is additional morbidity but prevents hip incongruity

Clinical Pearl

Clinical Significance: Quadrilateral plate medialization causes hip joint incongruity and accelerates arthritis EVEN IF columns are anatomically reduced. Address if significant.

Step 13: Final Fluoroscopic Confirmation

Obtain all views:

  • AP pelvis
  • Obturator oblique (anterior column, posterior wall)
  • Iliac oblique (posterior column, anterior wall)
  • Lateral

Checklist:

  1. Articular reduction <1mm step
  2. Column alignment anatomic
  3. NO intra-articular screws (arc intensifier through joint)
  4. Adequate screw purchase and length
  5. Quadrilateral plate position acceptable

Clinical Pearl

EXAM KEY: Screw malposition occurs in 3-8% despite careful technique. Judet views mandatory - fracture crosses both columns so both must be assessed.

Step 14: Repair External Rotators and Capsule

  • Heavy non-absorbable suture
  • Repair piriformis and obturator internus/gemelli (and capsule) to the greater trochanter, through trans-osseous tunnels if the cuff is poor
  • Capsular repair restores a posterior soft-tissue restraint
  • Assess hip stability through a range of motion after repair before closure

Step 15: Close and Postoperative Protocol

Closure:

  • Meticulous hemostasis (gluteal muscles bleed significantly)
  • Copious irrigation 3-6L saline
  • Place 14Fr drain deep to gluteus maximus
  • Close gluteal fascia (0-Vicryl), Scarpa's (2-0 Vicryl), skin (staples)

Postoperative Protocol:

  • Touch weight-bearing (10-20kg) × 6 weeks, progressive to full by 12 weeks
  • ROM exercises begin day 1-2
  • Posterior precautions if stability concern × 6-12 weeks
  • VTE prophylaxis: LMWH or DOAC × 35 days
  • HO prophylaxis: Indomethacin 75mg daily × 6 weeks
  • X-rays: 6 weeks, 12 weeks, 6 months, 12 months

Complications

Complications: Recognition, Prevention, and Management

Clinical Decision Scenarios

Use these scenarios to practise clinical reasoning and management decisions

CLINICAL SCENARIOStandard

CLINICAL PROMPT

"A 45-year-old man sustains a transverse acetabular fracture in a motorcycle accident. His AP pelvis shows a transverse line. How do you assess whether he needs surgery?"

PRACTICAL APPROACH
I would systematically assess this using the roof arc concept (Matta 1986) together with CT. On each of the three standard radiographs I measure a roof arc: I draw a vertical line through the geometric centre of the femoral head, then a second line from the head centre to the point where the fracture crosses the acetabular articular surface, and I measure the angle between them. The AP view gives the medial roof arc, the obturator oblique gives the anterior roof arc, and the iliac oblique gives the posterior roof arc. The same threshold of 45 degrees applies to all three: if all three arcs exceed 45 degrees the weight-bearing dome is preserved. If ANY arc is less than 45 degrees the dome is involved and operative fixation is indicated. I corroborate this on CT, where an intact subchondral arc in the superior 10mm of the dome supports a spared dome. I also note that the roof-arc rule only applies to fracture lines crossing the articular surface - it cannot be used for posterior-wall or both-column fractures. I assess the fracture level - transtectal through the dome has the worst prognosis, juxtatectal at the dome edge is intermediate, infratectal below the dome is best. CT with 3D reconstruction classifies the pattern and shows marginal impaction, quadrilateral-plate displacement and any associated posterior wall. Operative indications include: greater than 2mm articular step or gap, an incongruent hip, any roof arc less than 45 degrees, an associated posterior wall causing instability, or an intra-articular fragment.
CLINICAL SCENARIOStandard

CLINICAL PROMPT

"Describe Letournel's technique for anterior column screw placement from the posterior Kocher-Langenbeck approach"

PRACTICAL APPROACH
This is one of Letournel's most important contributions to acetabular surgery. The key insight is that transverse fractures divide the acetabulum into superior and inferior segments, crossing BOTH columns. Traditionally this would require combined anterior and posterior approaches with significant morbidity. Letournel demonstrated that by placing lag screws from the posterior column directed anteriorly toward the pelvic brim, you can achieve fixation of the anterior column through the posterior approach alone. After reducing and plating the posterior column through the Kocher-Langenbeck approach, I identify the entry point on the exposed posterior column. The screw trajectory is directed anteriorly and slightly superiorly toward the pelvic brim and anterior column. I use 3.5mm or 4.5mm cortical screws, obtaining lag effect across the fracture. Fluoroscopic guidance is essential - I use the AP view to ensure the screw stays within bone and doesn't exit medially toward vessels, the obturator oblique to see the anterior column trajectory, and the iliac oblique to confirm posterior column entry point. The screw must NOT penetrate the anterior cortex into soft tissues. This technique allows fixation of both columns from a single posterior approach in the majority of transverse fractures, avoiding the morbidity of combined ilioinguinal plus Kocher-Langenbeck approaches.
CLINICAL SCENARIOStandard

CLINICAL PROMPT

"A patient develops foot drop after transverse acetabular fracture ORIF. How do you manage this?"

PRACTICAL APPROACH
Sciatic nerve palsy is the most common nerve injury after acetabular surgery, occurring in 3-10% of transverse fracture fixations. My initial management involves urgent assessment to determine the mechanism. I examine the patient to define the deficit - complete sciatic palsy versus isolated peroneal or tibial division involvement. Peroneal division is more commonly affected, causing foot drop, ankle dorsiflexion weakness, and sensory loss over dorsum of foot. I review the operative images to check for hardware that might be compressing or penetrating near the nerve. If there is ANY concern about hardware impingement or nerve laceration based on imaging or intraoperative events, I would take the patient back for urgent exploration within 24-48 hours. However, the vast majority of cases are traction neuropraxia from retraction during the case. For these, management is conservative: immediate application of an AFO (ankle-foot orthosis) to prevent equinus contracture, physiotherapy referral for ROM and strengthening, and serial clinical examinations. I arrange neurology referral for formal EMG/nerve conduction studies at 3-6 weeks, repeated every 3 months to monitor for recovery. The prognosis is generally good - most traction neuropraxias recover over 6-18 months. I counsel the patient that permanent significant palsy occurs in less than 1% with careful technique. Throughout recovery, the AFO is essential to prevent fixed equinus deformity.

Transverse Acetabular Fracture ORIF - Exam Summary

Clinical summary

Evidence Base

Fractures of the acetabulum: a retrospective analysis (origin of the roof arc concept)

Level III
Matta JM, Anderson LM, Epstein HC, Hendricks P • Clin Orthop Relat Res
Clinical Implication: Provides the evidence basis for the 45-degree roof-arc rule used to decide whether the weight-bearing dome of a transverse fracture is involved and therefore needs operative fixation.
Verify on PubMed (PMID 3698382)

Fractures of the acetabulum: accuracy of reduction and clinical results in patients managed operatively within three weeks after the injury

Level IV
Matta JM • J Bone Joint Surg Am
Clinical Implication: Establishes anatomical reduction as the single most important controllable predictor of outcome and underpins early surgery by an experienced surgeon through the least morbid adequate approach.
Verify on PubMed (PMID 8934477)

Operative treatment of displaced fractures of the acetabulum: a meta-analysis

Level III
Giannoudis PV, Grotz MRW, Papakostidis C, Dinopoulos H • J Bone Joint Surg Br
Clinical Implication: Quantifies expected outcomes and complication rates for patient counselling and confirms that timing, approach choice and reduction quality are the levers the surgeon controls.
Verify on PubMed (PMID 15686228)

Outcomes of acetabular fracture fixation with ten years' follow-up

Level IV
Briffa N, Pearce R, Hill AM, Bircher M • J Bone Joint Surg Br
Clinical Implication: Confirms durable medium-to-long-term function after anatomic fixation while underlining that age, delay and reduction quality drive the minority who do poorly.
Verify on PubMed (PMID 21282764)

Two to twenty-year survivorship of the hip in 810 patients with operatively treated acetabular fractures

Level IV
Tannast M, Najibi S, Matta JM • J Bone Joint Surg Am
Clinical Implication: Benchmark long-term survivorship data confirming that anatomic reduction and avoiding extensile exposure protect the native hip - directly supporting single-approach fixation when adequate.
Verify on PubMed (PMID 22992846)

Guidelines, Registries & Global Practice

  • Specialist-centre referral (global consensus): displaced acetabular fractures are best managed in dedicated pelvic/acetabular units. UK BOAST (British Orthopaedic Association) guidance on pelvic and acetabular fractures, AO Foundation principles and the OTA all advocate early transfer to a high-volume centre, reflecting the surgeon-volume effect seen in the outcome literature.
  • Reduction quality as the universal benchmark: across AO, OTA and registry-derived series the operative target is anatomic reduction (≤1mm step ideally, ≤2mm acceptable on the Matta grade), which remains the dominant modifiable determinant of outcome worldwide.
  • Arthroplasty registries (NJR England/Wales, AOANJRR Australia, SHAR Sweden, AJRR USA) capture conversion of post-traumatic acetabular fractures to total hip arthroplasty; converted/post-trauma THA consistently shows higher complication and revision rates than primary THA, informing the threshold for acute THA in older patients.
  • Resource-stratified practice: in lower-resource settings, late presentation, limited fluoroscopy and intensive-care access shift practice toward fewer extensile approaches and a lower threshold for acute arthroplasty in older patients; the underlying biomechanical and reduction principles are unchanged.

References

  1. Letournel E, Judet R. Fractures of the Acetabulum. 2nd ed. Springer-Verlag; 1993. The definitive text on acetabular fracture classification and surgical treatment.

  2. Matta JM. Fractures of the acetabulum: accuracy of reduction and clinical results in patients managed operatively within three weeks after the injury. J Bone Joint Surg Am. 1996;78(11):1632-1645. PMID 8934477.

  3. Giannoudis PV, Grotz MR, Papakostidis C, Dinopoulos H. Operative treatment of displaced fractures of the acetabulum: a meta-analysis. J Bone Joint Surg Br. 2005;87(1):2-9. PMID 15686228.

3b. Matta JM, Anderson LM, Epstein HC, Hendricks P. Fractures of the acetabulum: a retrospective analysis (roof arc concept). Clin Orthop Relat Res. 1986;(205):230-240. PMID 3698382.

  1. Brooker AF, Bowerman JW, Robinson RA, Riley LH Jr. Ectopic ossification following total hip replacement: incidence and a method of classification. J Bone Joint Surg Am. 1973;55(8):1629-1632.

  2. Briffa N, Pearce R, Hill AM, Bircher M. Outcomes of acetabular fracture fixation with ten years' follow-up. J Bone Joint Surg Br. 2011;93(2):229-236. PMID 21282764. doi:10.1302/0301-620X.93B2.24056

  3. Tannast M, Najibi S, Matta JM. Two to twenty-year survivorship of the hip in 810 patients with operatively treated acetabular fractures. J Bone Joint Surg Am. 2012;94(17):1559-1567. PMID 22992846. doi:10.2106/JBJS.K.00444

  4. Kaempffe FA, Bone LB, Border JR. Open reduction and internal fixation of acetabular fractures: heterotopic ossification and other complications of treatment. J Orthop Trauma. 1991;5(4):439-445.

  5. Moed BR, Carr SE, Watson JT. Open reduction and internal fixation of posterior wall fractures of the acetabulum. Clin Orthop Relat Res. 2000;(377):57-67. PMID 10943185. doi:10.1097/00003086-200008000-00009

  6. Routt ML Jr, Swiontkowski MF. Operative treatment of complex acetabular fractures: combined anterior and posterior exposures during the same procedure. J Bone Joint Surg Am. 1990;72(6):897-904.

  7. Tile M, Helfet DL, Kellam JF. Fractures of the Pelvis and Acetabulum. 3rd ed. Lippincott Williams & Wilkins; 2003.