Judet-Letournel classification drives pattern-based surgical approach selection
- The Judet-Letournel system divides acetabular fractures into 5 elementary and 5 associated patterns (10 in total). Classification DETERMINES the surgical approach, the reduction sequence and the fixation strategy — it must be known cold.
- Posterior patterns (posterior wall/column, transverse, transverse plus wall, T-type) are exposed through the Kocher-Langenbeck approach, which accounts for about 80 percent of acetabular approaches. Anterior patterns and both-column fractures use the ilioinguinal or modified Stoppa approach.
- Two structures dominate the danger list: the sciatic nerve in the Kocher-Langenbeck approach (5-15 percent palsy rate, below piriformis) and the corona mortis in anterior/intrapelvic approaches (present in 30 percent, in the middle window).
- Operate when articular displacement at the weight-bearing dome is greater than 2 mm, the hip is unstable/subluxed, or fragments are incarcerated. The optimal window is 3-7 days; operate emergently (within 24 hours) for an irreducible dislocation, femoral head fracture or open fracture.
- Anatomic reduction (0-1 mm) is the single most important prognostic factor (Matta: 83 percent good outcomes versus 50 percent for a poor reduction). Every millimetre of residual step accelerates post-traumatic arthritis.
When & Why
The principle. Acetabular fractures are high-energy injuries. The aim of open reduction and internal fixation (ORIF) is to restore a congruent, stable weight-bearing dome so the femoral head articulates with an anatomically reduced acetabulum. Two questions drive every decision: does this fracture need surgery?, and through which approach? Both answers come from the Judet-Letournel classification.
Articular displacement greater than 2 mm at the weight-bearing dome; hip instability or subluxation; incarcerated intra-articular fragments; associated femoral head fracture (Pipkin); irreducible hip dislocation; open fracture; progressive sciatic nerve palsy. These mandate surgery.
Displacement of 1-2 mm in a young, active patient; posterior wall greater than 40 percent of the articular surface (unstable); marginal impaction needing elevation; roof arc angles less than 45 degrees (insufficient dome coverage); a high-demand occupation or athlete.
Displacement less than 2 mm at the dome; roof arc greater than 45 degrees on all three views; a stable hip on examination; a low-demand elderly patient with acceptable alignment; or severe comorbidity precluding surgery. Secondary congruence in a both-column fracture may permit non-operative care.
Articular displacement greater than 2 mm at the weight-bearing dome is the threshold for surgery because every millimetre of incongruity measurably increases peak articular contact pressure. Matta's outcome data underpin this: anatomic reduction (0-1 mm) gives 83 percent good outcomes, imperfect (2-3 mm) 68 percent, and poor (greater than 3 mm) only 50 percent. The dome carries peak loads, so perfect reduction there is essential. At 2.5 mm of dome displacement the risk of accelerated arthritis without surgery exceeds the risks of operating.
Roof arc angles and secondary congruence — when can you avoid surgery? Roof arc angles assess dome integrity on three views (AP, obturator oblique and iliac oblique). For each view, draw a vertical line through the centre of the femoral head and a second line from the centre to where the fracture exits the acetabulum, then measure the angle between them. If the angle is less than 45 degrees on any single view, dome coverage is insufficient and non-operative management will usually fail — all three views must be greater than 45 degrees to consider non-operative treatment. Secondary congruence is unique to both-column fractures: the femoral head remains congruent with the medialized, fractured acetabulum because both columns detach together from the intact ilium (the pathognomonic spur sign on the obturator oblique view). To rely on it you need roof arc greater than 45 degrees on all three views, a concentric femoral head on traction radiographs, no posterior wall component, and a patient who can comply with 6-12 weeks of touch-toe weight-bearing. Even with true secondary congruence, outcomes are slightly inferior to anatomic reduction, especially in young active patients.
Any posterior wall component destabilizes the hip and rules out non-operative care regardless of displacement. Loss of secondary congruence can occur silently — detect it with serial imaging. Touch-toe weight-bearing for 12 weeks is essential and non-negotiable; a non-compliant patient fails non-operative management.
Timing. The 3-7 day window is the sweet spot — soft tissues have settled but callus has not yet formed. Emergent injuries (within 24 hours) are dictated by the hip, not the acetabulum.
- Timeframe
- Within 24 hours
- Indications
- Irreducible dislocation, femoral head fracture, incarcerated fragments, open fracture
- Considerations
- AVN risk rises with delay
- Timeframe
- 24-72 hours
- Indications
- Reducible dislocation held in traction, vascular injury
- Considerations
- Soft tissue swelling may increase
- Timeframe
- 3-7 days
- Indications
- Most acetabular fractures
- Considerations
- Soft tissue settled, fracture not yet healing
- Timeframe
- 1-3 weeks
- Indications
- Medical optimization required
- Considerations
- Reduction still achievable, higher HO risk
- Timeframe
- Greater than 3 weeks
- Indications
- Unavoidable delay
- Considerations
- Callus impairs reduction; consider waiting until 6-8 weeks when consolidation reduces bleeding
After 3 weeks reduction becomes increasingly difficult. If you are forced to delay beyond 3 weeks, consider waiting until 6-8 weeks, when the fracture begins to consolidate — there is less bleeding and reduction is more predictable than operating in the difficult 3-6 week window.
Approach selection at a glance. The fracture pattern dictates the approach; the table below summarises the decision. The detailed 10-pattern classification sits in Background & Evidence.
- Patterns it exposes
- Posterior wall, posterior column, posterior column plus wall, transverse (most), transverse plus posterior wall, T-type (often) — about 80 percent of all acetabular approaches
- Key structure at risk
- Sciatic nerve (5-15 percent palsy); superior gluteal neurovascular bundle
- Patterns it exposes
- Anterior wall, anterior column, anterior column plus posterior hemitransverse, both column, T-type (anterior-predominant)
- Key structure at risk
- Corona mortis (30 percent); femoral nerve; external iliac vessels; LFCN
- Patterns it exposes
- Both column with quadrilateral-surface medialization, anterior column with medial displacement, pelvic brim plating; combine with a lateral window for complex patterns
- Key structure at risk
- Corona mortis; external iliac vessels; obturator nerve; bladder
- Patterns it exposes
- Largely abandoned — very morbid (50 percent or greater HO rate)
- Key structure at risk
- Avoid; staged anterior plus posterior approaches give equivalent access at lower morbidity
You cannot visualise a posterior wall through an anterior approach, and you cannot reach an anterior column through a posterior approach. For a both-column or T-type fracture where one approach will not achieve full reduction, stage a second approach 3-7 days later rather than using the extended iliofemoral — staged surgery gives equivalent access with far lower morbidity.
The Operation
The operation has one goal — an anatomic, stable reduction of the weight-bearing dome with extra-articular fixation — but the exposure is chosen by the pattern. The Kocher-Langenbeck approach is the workhorse and is laid out in full below as the primary operation; the ilioinguinal and modified Stoppa exposures follow, because their distinct window-by-window anatomy is the core of what the examiner asks. In every approach, the exposure is the operation.
The Kocher-Langenbeck approach — exposure, reduction and fixation
- Lateral decubitus (most common) or prone on a radiolucent table with full C-arm access for AP, inlet/outlet and Judet views; affected side up.
- Drape the limb free so the hip can be flexed, adducted and manipulated for reduction.
- Pad the down-side fibular head (peroneal nerve), place an axillary roll, and secure the pelvis with a bean-bag or pegs.
- Keep the hip in extension or neutral — flexion increases sciatic nerve tension.
- Document a pre-operative sciatic nerve exam (5-15 percent palsy risk) and plan mandatory HO prophylaxis.
- Incise from the posterior superior iliac spine (PSIS) toward the greater trochanter, then distally along the lateral femur for 10-15 cm.
- Split gluteus maximus in line with its fibres.
- Superficial interval: between gluteus maximus (inferior gluteal nerve) and gluteus medius/minimus (superior gluteal nerve); in practice the maximus is split in its own fibre line.
- Deep interval: between the short external rotators and the posterior hip capsule.
- The piriformis is the key landmark — the sciatic nerve exits the pelvis below it.
- Do not dissect proximal to the greater trochanter: the superior gluteal neurovascular bundle exits above piriformis (safe zone is distal to a point 3-5 cm above it). Injury causes permanent abductor weakness and cannot be repaired.
- Locate the sciatic nerve on the deep surface, below piriformis, BEFORE releasing any rotator.
- Pass a vessel loop and retract gently; release the retractors every 15-20 minutes to limit traction neurapraxia.
- Detach from the greater trochanter and tag with sutures: piriformis, superior gemellus, obturator internus, inferior gemellus.
- Retract them posteriorly, carrying the sciatic nerve out of harm's way.
- Protect quadratus femoris — it contains the medial femoral circumflex artery branches to the femoral head — and minimise capsular stripping, since the MFCA runs in the posterior capsule.
- Capsulotomy gives posterior column access.
- For a posterior wall fracture, dislocate the hip to see the wall directly: release the short rotators fully, complete the capsulotomy, then flex 90 degrees, adduct and internally rotate, levering the femoral head posteriorly over the acetabulum.
- Minimise dislocation time and repair the capsule at closure to protect the femoral head blood supply.
- Through K-L, reduce the posterior column first (the larger, stronger fragment; the intact ilium and sciatic buttress are the reference), then the anterior column usually follows through the dome; address wall fragments last.
- Tools: Weber, Farabeuf and Jungbluth clamps and a bone tenaculum; a ball-spike pusher and Cobb elevator; provisional 2.0 mm K-wires.
- Posterior wall: lag screws plus a buttress plate (a spring plate for marginal fragments).
- Posterior column: a reconstruction plate from the sciatic notch toward the ischium.
- Confirm reduction and that EVERY screw is extra-articular on AP, obturator oblique and iliac oblique views.
- Repair the short external rotators anatomically (reduces post-operative dislocation risk).
- Layered closure over a drain; begin HO prophylaxis within 24-72 hours.
The K-L approach uses two internervous intervals. Superficially, between gluteus maximus (inferior gluteal nerve) and gluteus medius (superior gluteal nerve) — the maximus is split in its fibre line rather than developing the interval. Deeply, between the short external rotators and the posterior hip capsule. The piriformis is the landmark: the sciatic nerve exits below it, the superior gluteal bundle above it. Releasing the short rotators (piriformis, superior gemellus, obturator internus, inferior gemellus) from the greater trochanter and retracting them posteriorly carries the sciatic nerve posteriorly and exposes the posterior column safely.
Lateral decubitus is most common — easier hip manipulation for reduction and the hip can be dislocated for wall fixation. Prone reduces venous bleeding, gives better superior posterior-column access and lets gravity assist exposure, but makes hip dislocation difficult. Choose lateral for most cases; consider prone for posterior column fractures where dislocation is not required.
Identify the nerve below piriformis before releasing the rotators and pass a vessel loop. Keep the hip in extension (flexion increases tension). Release retractors every 15-20 minutes. If the nerve looks injured intra-operatively, note its appearance and consider primary repair only if it is transected. Document the post-operative exam.
It exits above piriformis and supplies gluteus medius and minimus. Do not extend the dissection proximal to the greater trochanter — injury causes a Trendelenburg gait and permanent abductor weakness, and it cannot be repaired.
Ilioinguinal (anterior) — the three windows
The ilioinguinal approach — three windows
- Supine on a radiolucent table with a bolster under the ipsilateral buttock (10-15 degrees tilt) to improve iliac-wing access and reduce venous congestion.
- Both limbs draped free. A Foley catheter is MANDATORY (decompresses the bladder, reduces injury risk).
- C-arm for AP, inlet, outlet and Judet views; cell saver running; vascular instruments in the room; femoral artery marked before incision.
- From the pubic symphysis along the inguinal ligament to the ASIS, then posteriorly along the iliac crest for 8-10 cm (total 25-30 cm).
- Identify and protect the lateral femoral cutaneous nerve about 1 cm medial to the ASIS (10-15 percent injury rate).
- Incise the external oblique aponeurosis along the inguinal ligament.
- Elevate the iliacus from the iliac fossa. The interval is between iliacus (medial) and the abductors (lateral); the femoral nerve lies safely on the iliopsoas surface — retract the muscle, never the nerve.
- Access: iliac wing, SI joint, superior pelvic brim.
- Interval between the external iliac vessels (medially) and iliopsoas (laterally).
- Search the posterior aspect of the superior pubic ramus for the corona mortis — an obturator-external iliac anastomosis present in 30 percent — and ligate it prophylactically before it bleeds.
- Protect the external iliac vessels with vessel loops and retract gently; access the quadrilateral surface and pelvic brim.
- Interval between the vessels and the spermatic cord (or round ligament), protected with a vessel loop.
- Access the symphysis and superior pubic ramus; the bladder lies immediately posterior (Foley essential).
- Reduce the anterior column first (the foundation); the posterior column reduces indirectly through the intact dome in 60-70 percent.
- If the posterior column remains displaced greater than 2 mm after anterior fixation, do NOT convert to an extended iliofemoral — close and stage a Kocher-Langenbeck approach 3-7 days later.
- Fixation: a pelvic brim (suprapectineal) plate for the anterior column, with an infrapectineal plate where the quadrilateral surface needs buttressing.
- Meticulous fascial repair of the inguinal canal to prevent hernia (5-10 percent risk).
- Layered closure; confirm distal pulses and a stable pelvis on imaging.
Lateral window (iliacus/abductors): femoral nerve protected on iliopsoas; access iliac wing, SI joint, superior brim. Middle window (external iliac vessels/iliopsoas): the corona mortis danger; access quadrilateral surface and pelvic brim. Medial window (vessels/spermatic cord): bladder posterior; access symphysis and superior ramus. Develop them sequentially to avoid disorientation.
The corona mortis is an anastomosis between the obturator and external iliac (or inferior epigastric) vessels, present in roughly 30 percent (frequently venous). It lies on the posterior aspect of the superior pubic ramus. Identify it systematically, ligate or clip it prophylactically before dividing. If it bleeds: direct pressure for five minutes, then suture ligation on the ramus. Have the cell saver running and four units crossmatched before entering the middle window.
Modified Stoppa (intrapelvic)
The modified Stoppa (anterior intrapelvic) approach
- Supine. A Pfannenstiel (transverse) or midline (longitudinal) incision; a Foley catheter is mandatory.
- This is a preperitoneal plane between the bladder and pubic symphysis. Incise the rectus fascia in the midline between the recti and develop the space by blunt finger dissection — the peritoneum and bladder fall posteriorly. If you see bowel you have entered the peritoneum.
- Retract the bladder posteriorly with a padded retractor.
- Identify and ligate the corona mortis on the posterior pubic ramus; retract the external iliac vessels laterally.
- The obturator nerve runs along the lateral wall — retract it carefully.
- You now have a direct intrapelvic view of the quadrilateral surface.
- Reduce the quadrilateral surface and medial wall under direct vision; place an infrapectineal buttress plate along the pelvic brim.
- Add a separate lateral window (along the iliac crest) when iliac-wing or SI-joint access is also needed — the 'Stoppa plus lateral window' avoids the extensive inguinal dissection of the traditional ilioinguinal and lowers hernia risk.
Bladder injury (1-3 percent) — keep the Foley in and know the bladder position at all times. Peritoneal entry — if entered, close meticulously to prevent hernia. Obturator nerve — runs along the lateral wall, retract carefully. Corona mortis — ligate before it retracts and bleeds from the true pelvis. Limitations: it cannot access the SI joint or directly visualise the posterior column, and depth makes obese patients challenging.
Favour the modified Stoppa when there is significant quadrilateral-surface medialization needing direct buttress plating — it gives direct intrapelvic visualisation through the space of Retzius and easier infrapectineal plate placement, and can combine with a lateral window. Use the standard ilioinguinal when the quadrilateral surface is minimally displaced or when you need superior access to the iliac crest and SI joint. The AIP/modified Stoppa is a validated alternative (not replacement) to the ilioinguinal — counsel for the high rate of transient obturator nerve dysfunction.
Reduction and fixation principles
- Sequence
- Posterior column first, then anterior (usually follows through the dome), wall fragments last
- Why
- Posterior column is the larger, stronger fragment; intact ilium (sciatic buttress) is the reference; no direct access to reduce the anterior column first through K-L
- Sequence
- Anterior column first (the foundation), posterior column reduces indirectly in 60-70 percent
- Why
- Anterior column is accessible and becomes the reference; posterior follows through the intact dome; stage K-L if it remains displaced
Never reduce the wall before the column — the wall has nothing to reduce to. Do not force the anterior column through K-L (no access) — stage an ilioinguinal instead. Do not accept malreduction: each millimetre increases arthritis risk. Use adequate provisional fixation so the columns do not slip during definitive plating.
Intra-operative fluoroscopy. Four views confirm reduction and hardware position: AP pelvis (overall alignment and head concentricity); obturator oblique, 45 degrees toward the affected side (profiles the anterior column and shows the posterior wall en face); iliac oblique, 45 degrees away (profiles the posterior column and shows the anterior wall en face); and inlet/outlet if the pelvic ring is involved. Acceptable reduction: step less than 2 mm, gap less than 2 mm, concentric femoral head, smooth articular contour. Any intra-articular hardware must be removed and redirected.
- Residual displacement
- 0-1 mm
- Good clinical outcome
- 83 percent
- Residual displacement
- 2-3 mm
- Good clinical outcome
- 68 percent
- Residual displacement
- Greater than 3 mm
- Good clinical outcome
- 50 percent
Matta's data show only 50 percent good outcomes at greater than 3 mm versus 83 percent with anatomic reduction. Reassess the reduction technique (correct pull direction? interposed soft tissue or marginal impaction?), change the clamp position, elevate and graft any impacted bone, and consider staging an additional approach. Accept imperfection only after every option is exhausted — and document and counsel the patient.
- Primary fixation
- Lag screws plus buttress plate
- Supplemental options
- Spring plate for marginal fragments
- Primary fixation
- Reconstruction plate (sciatic notch to ischium)
- Supplemental options
- Long column screws for compression
- Primary fixation
- Pelvic brim plate (ilioinguinal)
- Supplemental options
- Infrapectineal plate (Stoppa)
- Primary fixation
- Buttress plate via Stoppa
- Supplemental options
- Suprapectineal plate via ilioinguinal
- Primary fixation
- Column screws plus plate
- Supplemental options
- Depends on approach used
Every screw must be confirmed extra-articular on fluoroscopy — AP pelvis, obturator oblique (anterior column screws) and iliac oblique (posterior column screws). An intra-articular screw guarantees arthritis. If there is any doubt, remove and redirect it.
Aftercare & Complications
Weight-bearing. Protected weight-bearing protects the reduction while it consolidates.
- Weight-bearing status
- Touch-toe weight-bearing (10-15 kg)
- Activity goals
- Range-of-motion exercises, transfers
- Weight-bearing status
- Partial weight-bearing (25-50 percent)
- Activity goals
- Increase mobility, stationary bike
- Weight-bearing status
- Progressive weight-bearing
- Activity goals
- Walking with aids, stairs
- Weight-bearing status
- Full weight-bearing as tolerated
- Activity goals
- Return to normal activities
Heterotopic ossification prophylaxis. The Kocher-Langenbeck approach carries the highest HO risk; prophylaxis is mandatory after K-L and recommended (not mandatory) after ilioinguinal or Stoppa.
Without prophylaxis, 20-30 percent develop significant HO (5-10 percent Brooker grade III-IV). First-line: indomethacin 25 mg three times daily for 6 weeks, started within 24-72 hours. Alternative: single-dose radiation 700-800 cGy within 24-72 hours (Moore/Anglen RCT: equivalent to indomethacin). Prefer radiation in renal impairment, NSAID contraindication, or polytrauma with concurrent long-bone fractures.
Lower baseline HO risk (5-15 percent). Give prophylaxis for complex patterns with extensive dissection, combined or staged approaches that include K-L, a prior history of HO, prolonged operative time, male sex, or a head-injured patient. Same protocol when used.
First-line is indomethacin 25 mg TDS for 6 weeks within 24-72 hours. If the patient has renal impairment (eGFR less than 30), peptic ulcer disease, aspirin-sensitive asthma, or anticoagulation, use single-dose radiation (700-800 cGy) within 24-72 hours. Critically, in polytrauma with concurrent long-bone fractures prefer radiation — Burd showed indomethacin increased long-bone nonunion to 26 percent versus 7 percent without. For patients on aspirin for cardiovascular protection, discuss the risk-benefit in an MDT.
Starting after 72 hours markedly reduces effectiveness. The full 6 weeks is required — do not stop early. Check renal function, GI history and bleeding risk before an NSAID. Omitting prophylaxis after K-L leaves an unacceptable 20-30 percent HO rate.
Follow-up. Surveillance tracks reduction, nerve recovery, HO maturation and arthritis.
- Timeframe
- 2 weeks
- Assessments
- Wound, nerve exam (sciatic/LFCN)
- Imaging
- None unless concerns
- Timeframe
- 6 weeks
- Assessments
- Clinical exam, ROM, weight-bearing progression
- Imaging
- AP plus Judet views
- Timeframe
- 3 months
- Assessments
- Function, nerve recovery, HO
- Imaging
- AP plus Judet views
- Timeframe
- 6 months
- Assessments
- Functional outcome, HO maturity
- Imaging
- AP plus Judet views
- Timeframe
- 12 months
- Assessments
- Final assessment, arthritis surveillance
- Imaging
- AP plus Judet views
- Timeframe
- 2, 5, 10 years
- Assessments
- Arthritis surveillance, THA planning
- Imaging
- AP pelvis
Complications. The table below consolidates recognition, prevention and management across all approaches.
- Recognition
- Post-operative foot drop, dorsum numbness (peroneal division) or tibial signs
- Prevention
- Identify below piriformis; vessel loop; hip in extension; release retractors every 15-20 min
- Management
- Examine and document; ankle splint; observe (70-90 percent recover over 12-18 months); EMG at 3-4 weeks; explore only if transection or worsening
- Recognition
- Lateral thigh numbness or dysaesthesia; tender Tinel
- Prevention
- Identify 1 cm medial to ASIS
- Management
- Reassurance; gabapentin if painful; usually permanent if divided
- Recognition
- Brisk arterial/venous bleeding in the middle window
- Prevention
- Identify and ligate prophylactically on the posterior pubic ramus
- Management
- Direct pressure 5 min; suture ligation on the ramus; cell saver; vascular standby
- Recognition
- Expanding haematoma, pulsatile bleeding
- Prevention
- Vessel loops, gentle retraction only
- Management
- Maintain pressure, do NOT clamp blindly; vascular surgery; primary repair
- Recognition
- Pain and stiffness at 6-12 weeks; Brooker grading on X-ray
- Prevention
- Mandatory prophylaxis after K-L (indomethacin or radiation)
- Management
- Maintain motion; excise Brooker III-IV only when mature (12-18 months) with post-op radiation plus indomethacin
- Recognition
- Progressive hip pain, joint-space narrowing
- Prevention
- Anatomic reduction (less than 2 mm)
- Management
- Conservative; THA conversion (10-30 percent at 10-20 years) — counsel that prior ORIF raises THA dislocation and infection rates
- Recognition
- Subchondral collapse at 6-24 months
- Prevention
- Minimise dislocation time; timely reduction of dislocation
- Management
- Observation; arthroplasty if symptomatic collapse
- Recognition
- Fever and wound erythema at ~10 days; raised inflammatory markers
- Prevention
- Operate at 3-7 days; prophylactic antibiotics within 60 min of incision; meticulous soft-tissue handling
- Management
- Early debridement within 24-48 h; deep cultures; empirical IV flucloxacillin plus gentamicin then culture-directed; ID input
- Recognition
- Calf pain/tenderness, dyspnoea
- Prevention
- Early mobilisation; LMWH for 4-6 weeks
- Management
- Anticoagulation; IVC filter if contraindicated
- Recognition
- Groin bulge, pain on straining
- Prevention
- Meticulous fascial repair of the inguinal canal at closure
Post-operative sciatic palsy after K-L occurs in 5-15 percent and is usually neurapraxia from retraction. Examine immediately, distinguish the peroneal from the tibial division and document; apply an ankle splint to prevent equinus; observe initially (70-90 percent recover over 12-18 months); obtain a baseline EMG at 3-4 weeks and review monthly. Explore only if transection is suspected (open injury), the deficit is worsening, or there is no sign of recovery by 4-6 months with complete denervation on EMG.
Reserve excision for Brooker grade III-IV causing functional limitation. Wait for maturity — typically 12-18 months — and confirm with a cold bone scan or serial X-rays showing no change. Plan with CT to map the HO and its relation to vessels and nerves, approach through the previous incision, and give mandatory post-operative prophylaxis (radiation 700-800 cGy within 24-72 hours AND indomethacin) plus aggressive physiotherapy. Excising immature HO recurs in nearly 100 percent.
Even with an anatomic reduction, 20-40 percent develop post-traumatic arthritis and 10-30 percent convert to THA over 10-20 years. Prior ORIF complicates any later THA (higher dislocation and infection rates). Document this counselling pre-operatively so patients understand the long-term outlook.
Viva & Exam Focus
PPAATThe five elementary patterns — PPAAT
LMMIlioinguinal windows — LMM
Sciatic nerve — 5-15 percent palsy rate, below piriformis; identify early, vessel loop, release retractors every 15-20 minutes, hip in extension. Superior gluteal neurovascular bundle — above piriformis, do not extend proximal to the greater trochanter. Medial femoral circumflex artery — posterior capsular branches; minimise capsular stripping.
Corona mortis — present in 30 percent; obturator-external iliac anastomosis; ligate prophylactically on the posterior pubic ramus. Femoral nerve — on iliopsoas; retract the muscle. LFCN — 10-15 percent injury; 1 cm medial to ASIS. External iliac vessels — middle window; vessel loops. Bladder (Stoppa) — Foley mandatory.
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“A 52-year-old man presents after a motorcycle crash with a displaced acetabular fracture. The X-ray shows disruption of both the iliopectineal and ilioischial lines with a 'spur sign' on the obturator oblique view. How would you classify this fracture and what is your approach?”
“Describe your approach to a 35-year-old woman with a transverse plus posterior wall acetabular fracture after a motor vehicle crash. The posterior wall fragment is 50 percent of the articular surface.”
“A 65-year-old man presents 10 days after a fall with an anterior column acetabular fracture. CT shows 4 mm displacement at the dome. What factors influence your surgical decision, and how would you approach this case?”
Classification (5 plus 5 equals 10)
- Elementary: posterior wall, posterior column, anterior wall, anterior column, transverse
- Associated: posterior column plus wall, transverse plus wall, T-type, anterior column plus posterior hemitransverse, both column
- Classification DETERMINES approach selection
Approach selection
- Kocher-Langenbeck: all posterior patterns (about 80 percent of cases)
- Ilioinguinal: anterior patterns plus both column
- Modified Stoppa: both column with quadrilateral medialization
- Staged anterior plus posterior is preferred over extended iliofemoral (lower morbidity)
Critical dangers
- K-L: sciatic nerve (5-15 percent), superior gluteal bundle (above piriformis)
- Ilioinguinal: corona mortis (30 percent), LFCN (10-15 percent), femoral nerve
- Stoppa: corona mortis, external iliac vessels, bladder
Timing
- Emergent: irreducible dislocation, femoral head fracture, open fracture
- Optimal: 3-7 days (soft tissue settled, no callus)
- Delayed beyond 3 weeks: consider waiting until 6-8 weeks
Key numbers
- Reduction goal: less than 2 mm step, less than 2 mm gap
- Roof arc: greater than 45 degrees on all views to consider non-operative
- K-L HO: 20-30 percent without prophylaxis, 5-10 percent with
- Long-term arthritis: 20-40 percent despite anatomic reduction
Reduction sequence
- K-L: posterior column first, then anterior follows, wall last
- Ilioinguinal: anterior column first; posterior reduces indirectly (60-70 percent)
- Matta outcomes: anatomic (0-1 mm) 83 percent good, poor (greater than 3 mm) 50 percent
Sciatic nerve protection
- Identify BELOW piriformis before releasing rotators
- Vessel loop and protect throughout
- Release retractors every 15-20 minutes
- Hip in extension (not flexion) reduces tension
Examiner favourites
- Three ilioinguinal windows: LMM (lateral, middle, medial)
- Spur sign is pathognomonic for both-column
- Secondary congruence: roof arc greater than 45 degrees all views, concentric head, no posterior wall
- HO prophylaxis: indomethacin 25 mg TDS for 6 weeks OR single-dose radiation 700-800 cGy; prefer radiation in polytrauma (Burd)
Background & Evidence
The Judet-Letournel classification. Acetabular fractures are classified into 10 patterns — five elementary (a single wall or column, or a single transverse break) and five associated (combinations). The classification is the foundation of management because it predicts the fracture geometry, dictates the surgical approach, and sets the reduction sequence and fixation strategy. It must be known cold.
- Description
- Posterior lip of the acetabulum
- Approach
- Kocher-Langenbeck
- Key features
- Most common (~25 percent); dislocation common
- Description
- Fracture line from sciatic notch to obturator foramen
- Approach
- Kocher-Langenbeck
- Key features
- Ischiopubic segment separates
- Description
- Anterior lip of the acetabulum
- Approach
- Ilioinguinal
- Key features
- Rare (~2 percent); small fragment
- Description
- Fracture from crest through the ischiopubic ramus
- Approach
- Ilioinguinal
- Key features
- Variable height of fracture exit
- Description
- Divides the acetabulum into superior and inferior
- Approach
- K-L (usually) or ilioinguinal
- Key features
- Level: transtectal, juxtatectal, infratectal
- Components
- Posterior column plus posterior wall
- Approach
- Kocher-Langenbeck
- Key features
- Two posterior elements involved
- Components
- Transverse plus a posterior wall fragment
- Approach
- Kocher-Langenbeck
- Key features
- Wall fragment determines stability
- Components
- Transverse plus a vertical split of the ischiopubic segment
- Approach
- K-L, plus ilioinguinal if needed
- Key features
- May need a combined or staged approach
- Components
- Anterior column plus a posterior hemitransverse
- Approach
- Ilioinguinal
- Key features
- Anterior column reduces, posterior follows
- Components
- Both columns detached from an intact ilium
- Approach
- Ilioinguinal or Stoppa
- Key features
- Spur sign; secondary congruence possible
Reading the radiographs. Two lines define the columns on the AP pelvis: the iliopectineal line traces the anterior column and the ilioischial line traces the posterior column. A both-column fracture disrupts both, and the obturator oblique view shows the spur sign — the intact ilium projecting as a spur, pathognomonic for a both-column fracture. The Judet views (obturator and iliac oblique) profile each column and wall in turn and, with the AP, give the three roof arc measurements that judge dome integrity. Why approach selection is everything. The classification is not an academic exercise — it is the operational plan. A posterior pattern approached anteriorly cannot be visualised or reduced, and vice versa. The T-type and both-column patterns are where judgement is tested, because a single approach may not achieve full reduction; the modern, lower-morbidity answer is a staged anterior-plus-posterior sequence rather than the morbid extended iliofemoral, which has been largely abandoned for its 50 percent-plus HO rate. Outcomes and the evidence base. Across the literature, quality of reduction is the dominant controllable determinant of outcome. Matta showed that anatomic reduction tracks with clinical results and that reduction quality falls with fracture complexity, older age and surgical delay — the evidence behind operating at 3-7 days and chasing an anatomic reduction. Giannoudis's meta-analysis confirmed post-traumatic arthritis as the commonest long-term complication (about 20 percent), with HO and femoral-head AVN each under 10 percent. The full citations sit in References below.
References
Fractures of the acetabulum: accuracy of reduction and clinical results within three weeks of injury
- 262 displaced acetabular fractures, ORIF within 21 days, mean 6-year follow-up
- Anatomical reduction (0-1mm) achieved in 71 percent; rate fell with fracture complexity, older age and surgical delay
- Excellent/good clinical result in 76 percent overall (40 percent excellent, 36 percent good); outcome closely tracked radiographic reduction
- Femoral head osteonecrosis 3 percent, THA conversion 6 percent at mean 6 years
Operative treatment of displaced fractures of the acetabulum: a meta-analysis
- Pooled analysis of 3670 operatively treated acetabular fractures
- Post-traumatic osteoarthritis was the commonest long-term complication at approximately 20 percent
- Heterotopic ossification and femoral head avascular necrosis each occurred in under 10 percent; reoperation (usually THA) in 8 percent
- 75-80 percent achieved excellent or good results at mean 5 years
The anterior intra-pelvic (modified Rives-Stoppa) approach for fixation of acetabular fractures
- 57 consecutive acetabular fractures via the anterior intrapelvic approach; a supplemental lateral window was needed in 60 percent
- Excellent/good reduction in 92 percent (70 percent excellent, 22 percent good); excellent/good Merle d'Aubigne outcome in 91 percent at 1 year
- Transient obturator nerve palsy in 26 percent — all but one resolved within 6 months
- Complication profile comparable to the ilioinguinal approach
Indomethacin versus radiation therapy for prophylaxis against heterotopic ossification in acetabular fractures: a randomised, prospective study
- 72 patients randomised after ORIF (mostly Kocher-Langenbeck or combined approaches)
- Indomethacin 25mg three times daily for 6 weeks versus single-dose 800 cGy within 3 days
- No significant difference in Brooker-grade heterotopic ossification between the two methods
- Both safe and effective; radiation was around 200 times more costly at the study institution
Heterotopic ossification prophylaxis with indomethacin increases the risk of long-bone nonunion
- 112 patients with acetabular plus concomitant long-bone fractures, randomised to indomethacin, radiation or no prophylaxis
- Long-bone nonunion rate 26 percent with indomethacin versus 7 percent without (p=0.004)
- NSAID exposure, not radiation, drove the excess nonunion risk
A cadaveric study on the obturator neurovascular bundle with emphasis on high prevalence of venous corona mortis
- 73 cadaveric hemipelves dissected for retropubic obturator-external iliac anastomoses
- Abnormal/anastomotic obturator vessels present in 51 percent of hemipelves, with venous corona mortis predominating
- Most anomalous obturator veins drained into the external iliac vein
Fractures of the acetabulum: classification and surgical approaches for open reduction
The original description of the Judet-Letournel classification of acetabular fractures and the surgical approaches for their open reduction — the foundation of modern acetabular surgery.
Fractures of the Acetabulum (2nd edition)
The definitive monograph on acetabular fractures: classification, imaging, surgical approaches and long-term results.
Ectopic ossification following total hip replacement: incidence and a method of classification
The Brooker classification of heterotopic ossification — the standard grading system used throughout this topic.
Acetabular fracture fixation via a modified Stoppa limited intrapelvic approach
The original description of the modified Stoppa (limited intrapelvic) approach for acetabular fracture fixation.