High-yield overview

Ilioinguinal (three windows) or modified Stoppa approach for quadrilateral plate access | advanced

Absolute Indications:

Displaced anterior column fracture with greater than 2mm step or gap at articular surface
Roof arc angle less than 45 degrees on AP view (dome involvement)
Roof arc angle less than 25 degrees on oblique views
Incongruous hip joint on CT scan
Associated anterior wall component with displacement

Relative Indications:

Marginal roof impaction on CT
Quadrilateral plate medialization threatening joint congruity
Young, active patient with anatomically reducible fracture
Polytrauma patient requiring early mobilization

Critical Danger Structures

Danger 1

External iliac vessels. Location: Middle window between iliacus and psoas - 10-15mm from pelvic brim

Danger 2

Femoral nerve. Location: Lateral to external iliac artery in iliopsoas groove - retract laterally with iliopsoas

Danger 3

Lateral femoral cutaneous nerve. Location: Exits pelvis 10-20mm medial to ASIS under inguinal ligament

Danger 4

Corona mortis. Location: Behind superior pubic ramus, mean ~52mm (range ~38-68mm) from symphysis - anastomosis present in up to ~70%, clinically significant/arterial variant in ~30-40% - MUST ligate

Danger 5

Obturator nerve and vessels. Location: Obturator foramen - protect with Hohmann retractor in medial window

Danger 6

Spermatic cord/round ligament. Location: Medial window - retract medially with soft Penrose drain

Mnemonic

LMMTHREE WINDOWS

Mnemonic

CORONACORONA MORTIS

Surgical Anatomy

The ilioinguinal approach provides access through three anatomical windows created between neurovascular structures:

Lateral Window:

Created by elevating external oblique aponeurosis from iliac crest
Subperiosteal elevation of iliacus from inner table
Exposes iliac wing from SI joint to ASIS
No major neurovascular structures at risk
Used for proximal fracture reduction and plate fixation

Middle Window (Critical):

Between external iliac vessels (retracted medially) and iliopsoas/femoral nerve (retracted laterally)
This is the internervous interval - NO muscle splitting
Exposes pelvic brim from AIIS to iliopectineal eminence
Primary working window for anterior column plating
External iliac artery/vein 10-15mm from pelvic brim

Medial Window:

Between iliopsoas (lateral) and spermatic cord/round ligament (medial)
Exposes quadrilateral plate and superior pubic ramus
Corona mortis must be identified and ligated
Obturator nerve/vessels protected with Hohmann in obturator foramen

Modified Stoppa Approach:

Alternative for medial wall/quadrilateral plate access
Pfannenstiel incision 2-3cm above symphysis
Rectus muscles retracted laterally
Space of Retzius developed
Direct view of quadrilateral plate from medial side
Can be combined with lateral window of ilioinguinal

Positioning and Preparation

Patient Position: Supine on radiolucent flat-top table with folded towel under ipsilateral buttock (15-20 degree rotation toward contralateral side improves pelvic brim access)

Surgical Approach: Ilioinguinal three-window approach or modified Stoppa for quadrilateral plate-predominant fractures

Incision:

Ilioinguinal: From ASIS along iliac crest 6-8cm, then curving anteromedially toward pubic symphysis (total 15-20cm)
Modified Stoppa: Pfannenstiel incision 2-3cm above symphysis (10-12cm) with optional lateral extension

Pre-incision Checklist:

Confirm fluoroscopy views before draping (AP, inlet, outlet, both Judets)
Foley catheter in place
Antibiotics administered (cefazolin 2g IV within 60 minutes)
DVT prophylaxis

Operative Technique

Step 1: Position patient supine on radiolucent table

Position patient supine on radiolucent table with folded towel under ipsilateral buttock to rotate pelvis 15-20 degrees toward contralateral side. This rotation improves access to pelvic brim and facilitates fluoroscopic imaging. Insert Foley catheter to decompress bladder and monitor urine output. Ensure C-arm can obtain AP, inlet (40 degrees caudal), outlet (40 degrees cranial), and obturator/iliac oblique (Judet) views before draping.

Clinical Pearl

EXAM KEY: Proper positioning critical - towel rotation improves pelvic brim visualization. Test all fluoroscopy views before prepping - repositioning mid-surgery is disruptive and wastes time.

Dangers at this step

Inadequate rotation limits pelvic brim access
Bladder injury if catheter not placed before surgery

Step 2: Mark skin incision for ilioinguinal approach

Mark skin incision beginning at ASIS, following iliac crest medially for 6-8cm, then curving anteriorly and inferiorly toward pubic symphysis. Total incision length 15-20cm depending on patient size and fracture extent. Identify ASIS, pubic tubercle, and inguinal ligament as landmarks. Mark lateral femoral cutaneous nerve exit point (10-20mm medial to ASIS).

Clinical Pearl

EXAM KEY: The three-window approach provides comprehensive anterior column access. Lateral window = iliac wing, Middle window = pelvic brim (main working window), Medial window = quadrilateral plate.

Dangers at this step

Incision too short limits exposure
LFCN injury if incision placed directly over nerve

Step 3: Develop lateral window

Incise skin and subcutaneous tissue to iliac crest. Identify and protect LFCN if encountered (10-20mm medial to ASIS). Elevate external oblique aponeurosis from iliac crest laterally. Continue subperiosteally elevating iliacus from inner table of ilium using Cobb elevator. Expose iliac wing from SI joint posteriorly to ASIS anteriorly. Place Hohmann retractors over crest to maintain exposure.

Clinical Pearl

EXAM KEY: Lateral window provides access to iliac wing fractures and allows placement of proximal screws. Purely subperiosteal dissection - no neurovascular structures at risk if staying on bone.

Dangers at this step

LFCN neuropraxia from retraction (15-30% incidence)
Superior gluteal artery if dissection extends too far posteriorly beyond SI joint

Step 4: Develop middle window (critical)

Identify the interval between external iliac vessels (located medially) and the iliopsoas muscle with femoral nerve (located laterally). This is the TRUE internervous plane of the ilioinguinal approach. Gently retract external iliac vessels medially with malleable retractor placed deep to vessel loops. Retract iliopsoas and femoral nerve laterally. Clear fracture hematoma. Expose pelvic brim from AIIS to iliopectineal eminence.

Clinical Pearl

EXAM KEY: Middle window is the PRIMARY working window where most anterior column plates are positioned. External iliac vessels are only 10-15mm from pelvic brim - GENTLE retraction only. Femoral nerve lies on iliopsoas muscle.

Dangers at this step

External iliac vessel injury (catastrophic bleeding)
Femoral nerve neuropraxia from excessive retraction
Lymphatic injury causing lymphocele

Step 5: Develop medial window

Identify interval between iliopsoas muscle (lateral) and spermatic cord in males/round ligament in females (medial). Retract spermatic cord/round ligament medially with soft Penrose drain. Elevate iliopsoas from pelvic brim. Identify and LIGATE the corona mortis if present (an obturator-to-external-iliac/inferior-epigastric anastomosis on the retropubic surface of the superior ramus, mean ~52mm and as close as ~38mm from the symphysis). Place Hohmann retractor into obturator foramen to protect obturator neurovascular bundle. Expose quadrilateral plate and superior pubic ramus.

Clinical Pearl

EXAM KEY: Corona mortis MUST be actively sought and ligated - arterial and venous connections both possible. If injured, vessel retracts into pelvis causing difficult-to-control bleeding. Two clips on each side before cutting.

Dangers at this step

Corona mortis hemorrhage (potentially catastrophic)
Obturator nerve/vessel injury
Bladder injury with medial dissection

Step 6: Modified Stoppa approach (alternative)

For quadrilateral plate-predominant fractures: Make Pfannenstiel incision 2-3cm above pubic symphysis. Divide anterior rectus sheath transversely. Retract rectus muscles laterally to develop space of Retzius (retropubic space). Elevate peritoneum and bladder superiorly with ribbon retractor. Access quadrilateral plate directly from medial aspect. Provides superior visualization of medial wall compared to ilioinguinal medial window.

Clinical Pearl

EXAM KEY: Stoppa approach increasingly popular for anterior column with quadrilateral plate involvement. Can combine with ilioinguinal lateral window (first window) for extended access while avoiding middle and medial window neurovascular risks.

Dangers at this step

Bladder injury during space of Retzius development
External iliac vein injury at pelvic brim

Step 7: Reduce fracture - work from proximal to distal

Use ball spike pusher to manipulate iliac wing fragment. Establish stable reduction of proximal fragment to stable iliac wing first. Then reduce pelvic brim fracture working distally using pointed reduction forceps. Reduce articular surface to less than 1mm step/gap. Use Farabeuf clamps or large pelvic reduction clamps across brim to maintain reduction. Verify reduction visually through windows and with fluoroscopy on all views.

Clinical Pearl

EXAM KEY: Reduction sequence critical - establish stable proximal reference (iliac wing) then work distally to pubic ramus. Pelvic brim reduction determines articular congruity. Anatomic brim = anatomic joint.

Dangers at this step

Inadequate reduction leads to poor outcome
Iatrogenic fracture comminution with forceful reduction
Clamp injury to vessels if placed without direct visualization

Step 8: Provisionally fix with K-wires or lag screws

Once anatomic reduction achieved, hold with 2.0mm K-wires across fracture. Consider provisional lag screws (3.5mm cortical) if fracture geometry allows. Confirm reduction on AP and BOTH Judet views before definitive plating. Assess articular reduction through windows - should be less than 1mm step/gap. Check roof arc measurements on fluoroscopy confirm dome not involved.

Clinical Pearl

EXAM KEY: Do NOT proceed to plating without confirming anatomic reduction on all views (AP + both Judets). Once plate applied and screws tightened, reduction cannot be easily adjusted. K-wires allow revision if needed.

Dangers at this step

Accepting malreduction (leads to arthritis)
Joint penetration with provisional K-wires

Step 9: Apply reconstruction plate along pelvic brim

Contour 3.5mm pelvic reconstruction plate (8-10 holes) to match pelvic brim curvature precisely. Position plate from iliac wing (proximal) across anterior column to superior pubic ramus (distal). Place minimum 3 screws in iliac wing segment, 3-4 screws across pelvic brim, 2-3 screws in pubic ramus. All screws directed away from hip joint. Confirm no articular penetration on fluoroscopy.

Clinical Pearl

EXAM KEY: Plate MUST be precisely contoured to pelvic brim anatomy - poorly contoured plate displaces fracture when screws tightened. Use plate benders progressively. Test fit before drilling.

Dangers at this step

Loss of reduction from poor plate contouring
Intra-articular screw penetration
Neurovascular injury from long screws

Step 10: Add lag screws where fracture geometry allows

Simple fracture patterns may allow independent lag screw fixation through or outside plate. Use 3.5mm or 4.5mm cortical screws in lag fashion. Ensure compression perpendicular to fracture plane. Measure carefully and confirm no joint penetration on all fluoroscopy views including Judets.

Clinical Pearl

EXAM KEY: Lag screws provide interfragmentary compression - biomechanically superior to plate-only neutralization when fracture geometry favorable. Check screw length on AP AND both Judet views.

Dangers at this step

Intra-articular screw (even 1-2mm penetration damages cartilage)
Over-compression causing comminution

Step 11: Address quadrilateral plate if medially displaced

Quadrilateral plate medialization common with anterior column fractures, causing loss of hip joint congruity (femoral head subluxation). If displaced: apply buttress plate from medial approach (Stoppa or ilioinguinal medial window). Infrapectineal plate or curved quadrilateral buttress plate positioned to prevent medial subluxation. Spring plate technique for comminuted medial wall.

Clinical Pearl

EXAM KEY: Quadrilateral plate medialization NOT addressed by anterior column plate alone - requires specific medial buttress fixation. Femoral head follows medial wall - if wall goes medial, head subluxes medially = poor outcome.

Dangers at this step

Missing medial wall displacement (subluxation postop)
Obturator nerve injury during infrapectineal plating

Step 12: Obtain final fluoroscopic images

Obtain complete fluoroscopic series: AP pelvis, inlet view (40 degrees caudal tilt), outlet view (40 degrees cranial tilt), obturator oblique (45 degrees toward affected side), iliac oblique (45 degrees away). Assess articular reduction (less than 1mm step/gap), implant position, screw lengths, joint penetration. Rotate C-arm through arc to dynamically assess joint space for screw penetration.

Clinical Pearl

EXAM KEY: Judet views essential - Obturator oblique shows anterior column and posterior wall (look INTO obturator foramen). Iliac oblique shows posterior column and anterior wall. Dynamic arc through joint catches occult penetration.

Dangers at this step

Missing intra-articular hardware
Accepting malreduction visible on oblique views

Step 13: Irrigate and achieve hemostasis

Copious irrigation with 3-6 liters warm normal saline. Achieve meticulous hemostasis with bipolar electrocautery - avoid monopolar near vessels/nerves. Place closed suction drains (14Fr flat Blake drain) in each window due to large dead space. Bring drains out through separate stab incisions lateral to main wound.

Clinical Pearl

EXAM KEY: Hematoma formation increases infection risk and delays wound healing. Drains reduce hematoma - remove when output less than 30-50mL per 24 hours (typically 24-48 hours postoperatively).

Dangers at this step

Electrocautery injury to vessels/nerves
Hematoma if inadequate hemostasis

Step 14: Close in layers

Repair external oblique aponeurosis to iliac crest periosteum with 0 Vicryl interrupted sutures. Close inguinal ligament repair/transversalis fascia. Close Scarpa's fascia with 2-0 Vicryl. Skin closure with staples or 3-0 Monocryl subcuticular. Apply sterile adhesive dressing. Consider abdominal binder for patient comfort.

Clinical Pearl

EXAM KEY: Meticulous fascial closure reduces inguinal hernia risk (2-5% with ilioinguinal approach). External oblique must be securely reattached to crest. Hernia more common if fascial closure inadequate.

Dangers at this step

Inguinal hernia from inadequate fascial repair
Wound dehiscence

Step 15: Postoperative protocol

Touch weight bearing (10kg foot-flat) for 6 weeks, then progressive weight bearing to full by 12 weeks. Hip ROM exercises begin postoperative day 1-2 (avoid active hip flexion against resistance for 6 weeks to protect iliopsoas repair). VTE prophylaxis with LMWH (enoxaparin 40mg daily) or DOAC (rivaroxaban 10mg daily) for minimum 35 days. Follow-up radiographs at 2 weeks (wound check), 6 weeks, 12 weeks, 6 months, 12 months. CT at 6-12 weeks if reduction quality uncertain.

Clinical Pearl

EXAM KEY: Protected weight bearing allows fracture healing while preventing fixation failure. Early ROM prevents stiffness. VTE prophylaxis MANDATORY - pelvic trauma with immobilization = very high risk for DVT/PE.

Dangers at this step

VTE without adequate prophylaxis
Fixation failure with premature weight bearing
Stiffness without early ROM

Complications

Complications: Recognition, Prevention & Management

Evidence Base

Fractures of the acetabulum: accuracy of reduction and clinical results managed operatively within three weeks

Level IV

Matta JM • J Bone Joint Surg Am

Clinical Implication: The seminal outcome study establishing that anatomic articular reduction is the single most important surgeon-controlled determinant of hip survival - the rationale for accepting nothing greater than 1mm step/gap in anterior column ORIF.

Verify on PubMed (PMID 8934477)

Acetabular fracture fixation via a modified Stoppa limited intrapelvic approach: operative technique and preliminary results

Level IV

Cole JD, Bolhofner BR • Clin Orthop Relat Res

Clinical Implication: Defines the modified Stoppa as a safe alternative to the ilioinguinal medial window, particularly for quadrilateral-plate-predominant anterior column fractures.

Verify on PubMed (PMID 8050220)

Comparison of acetabular fracture reduction quality by the ilioinguinal or the anterior intrapelvic (modified Rives-Stoppa) approaches

Level III

Shazar N, Eshed I, Ackshota N, Hershkovich O, Khazanov A, Herman A • J Orthop Trauma

Clinical Implication: Supports preferential use of the anterior intrapelvic/modified Stoppa approach where quadrilateral-plate or both-column reduction is required, while either approach remains valid for simple anterior column patterns.

Verify on PubMed (PMID 24100918)

An anatomical study of corona mortis and its clinical significance

Level IV

Hong HX, Pan ZJ, Chen X, Huang ZJ • Chin J Traumatol

Clinical Implication: Provides the evidence-based location and prevalence that mandate deliberate identification and ligation of the corona mortis before developing the medial window.

Verify on PubMed (PMID 15294115)

The anatomical variability of obturator vessels: systematic review of literature

Level I

Marvanova Z, Kachlik D • Ann Anat

Clinical Implication: Quantifies the high overall prevalence of aberrant obturator connections and explains why both arterial and (more commonly) venous corona mortis must be anticipated during anterior acetabular exposure.

Verify on PubMed (PMID 37865385)

Clinical Decision Scenarios

Use these scenarios to practise clinical reasoning and management decisions

CLINICAL SCENARIOStandard

CLINICAL PROMPT

"Tell me about the corona mortis and why it's clinically important in acetabular surgery"

PRACTICAL APPROACH

The corona mortis - meaning 'crown of death' - is a vascular anastomosis between the obturator vessels and either the external iliac or inferior epigastric vessels, running on the retropubic surface of the superior pubic ramus. Anatomical studies show it is far more common than once taught: an anastomotic connection is present in around 70% of hemipelves, with a clinically significant arterial variant in roughly 30-40%. It typically lies a mean of about 52mm from the pubic symphysis (range roughly 38 to 68mm), so a practical rule is to assume a vessel may be present within about 55mm of the symphysis. The clinical importance is twofold. First, if injured during medial window development of the ilioinguinal approach, it causes significant bleeding that is difficult to control because the vessel retracts into the pelvic side wall and soft tissues. Second, it can be either arterial, venous, or both - the arterial variant being more dangerous with higher-pressure bleeding. My surgical practice is to actively search for and ligate this vessel BEFORE developing the medial window. I identify it by carefully dissecting along the superior pubic ramus between the iliopsoas and spermatic cord. When found, I apply two clips on each side before dividing it. If it's injured unexpectedly, I control bleeding with direct pressure, then systematically identify both ends for ligation - which may require extending the exposure.

CLINICAL SCENARIOStandard

CLINICAL PROMPT

"Explain the three windows of the ilioinguinal approach and what structures are at risk in each"

PRACTICAL APPROACH

The ilioinguinal approach creates three anatomical windows between neurovascular structures to access different parts of the anterior pelvis. The LATERAL WINDOW is created by elevating the external oblique aponeurosis from the iliac crest, then subperiosteally elevating the iliacus muscle from the inner table of the ilium. This exposes the iliac wing from the SI joint posteriorly to the ASIS anteriorly. There are minimal neurovascular structures at risk here as long as dissection stays subperiosteal. The lateral femoral cutaneous nerve exits 10-20mm medial to the ASIS and should be protected. The MIDDLE WINDOW is the critical working window where most plating is performed. It lies between the external iliac vessels medially and the iliopsoas muscle with femoral nerve laterally. This is a true internervous interval. The external iliac artery and vein are only 10-15mm from the pelvic brim, requiring gentle retraction only. The femoral nerve lies on the iliopsoas muscle and is retracted laterally with it. The MEDIAL WINDOW lies between the iliopsoas laterally and the spermatic cord (or round ligament in females) medially. This provides access to the quadrilateral plate and superior pubic ramus. Key structures at risk include the corona mortis on the superior pubic ramus and the obturator neurovascular bundle in the obturator foramen.

CLINICAL SCENARIOStandard

CLINICAL PROMPT

"How do you interpret Judet views and what does each view show?"

PRACTICAL APPROACH

Judet views are 45-degree oblique radiographs essential for acetabular fracture assessment. They are named based on which side of the pelvis is elevated. The OBTURATOR OBLIQUE is taken with the affected hip rotated 45 degrees toward the X-ray beam - essentially the patient is rolled toward the affected side with that hip down. This view profiles the anterior column and posterior wall. I remember this because you're looking 'into' the obturator foramen on this view - and the structures you see clearly are the anterior column (as a continuous line from iliac crest to pubic ramus) and the posterior wall (as the posterior acetabular rim). If either is disrupted, you'll see the fracture on this view. The ILIAC OBLIQUE is taken with the affected hip rotated 45 degrees away from the X-ray beam - the patient is rolled away from the affected side with that hip up. This view profiles the posterior column and anterior wall. You're looking at the iliac wing en face, which is why it's called the iliac oblique. The structures visualized are the posterior column (greater sciatic notch to ischium) and the anterior wall (anterior acetabular rim). For roof arc measurements, I measure the angle from the geometric center of the femoral head to the fracture line on each view. If AP roof arc is less than 45 degrees or oblique roof arcs are less than 25 degrees, the weight-bearing dome is involved and surgery is typically indicated.

Anterior Column Acetabular Fracture ORIF - Exam Summary

Clinical summary

References

Letournel E, Judet R. Fractures of the Acetabulum. 2nd ed. Springer-Verlag; 1993.
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.
Cole JD, Bolhofner BR. Acetabular fracture fixation via a modified Stoppa limited intrapelvic approach. Description of operative technique and preliminary treatment results. Clin Orthop Relat Res. 1994;(305):112-123. PMID: 8050220.
Shazar N, Eshed I, Ackshota N, Hershkovich O, Khazanov A, Herman A. Comparison of acetabular fracture reduction quality by the ilioinguinal or the anterior intrapelvic (modified Rives-Stoppa) surgical approaches. J Orthop Trauma. 2014;28(6):313-319. PMID: 24100918. doi:10.1097/01.bot.0000435627.56658.53.
Hong HX, Pan ZJ, Chen X, Huang ZJ. An anatomical study of corona mortis and its clinical significance. Chin J Traumatol. 2004;7(3):165-169. PMID: 15294115.
Khirul-Ashar NA, Ismail II, Hussin P, et al. The incidence and variation of corona mortis in multiracial Asian: an insight from 82 cadavers. Malays Orthop J. 2024;18(1):26-32. PMID: 38638662. doi:10.5704/MOJ.2403.004.
Marvanova Z, Kachlik D. The anatomical variability of obturator vessels: systematic review of literature. Ann Anat. 2023;251:152167. PMID: 37865385. doi:10.1016/j.aanat.2023.152167.
Hirvensalo E, Lindahl J, Böstman O. A new approach to the internal fixation of unstable pelvic fractures. Clin Orthop Relat Res. 1993;(297):28-32. PMID: 8242945.
Tile M, Helfet DL, Kellam JF. Fractures of the Pelvis and Acetabulum. 3rd ed. Lippincott Williams & Wilkins; 2003.

Pattern	Preferred Approach
Anterior column only	Ilioinguinal or Stoppa
Anterior + quadrilateral plate	Modified Stoppa preferred
Anterior column + posterior hemitransverse	Ilioinguinal (extended)
Both column (anterior predominant)	Ilioinguinal