Open Book Pelvic Fracture

Open book pelvic fracture is the anteroposterior compression (APC) pattern of pelvic ring injury. An external rotation force opens the pelvis like a book, with disruption of the pubic symphysis or rami and the sacroiliac ligaments. It follows high energy trauma such as motorcycle collisions, head on vehicle collisions, crush injuries and falls.

Pelvic ring fractures make up about 3% of skeletal fractures, and unstable patterns carry a high mortality when haemodynamic instability is present. Haemorrhage is the main cause of death.

The Young-Burgess classification grades the injury. APC I: symphyseal diastasis of under 2.5 cm, posterior ligaments intact, stable. APC II: diastasis of over 2.5 cm with disruption of the anterior sacroiliac, sacrospinous and sacrotuberous ligaments, rotationally unstable, vertically stable. APC III: complete disruption of the posterior sacroiliac ligaments, rotationally and vertically unstable.

Associated injuries are bladder and urethral rupture (higher in men), vaginal or rectal injury (open pelvic fracture), lumbosacral plexus injury, abdominal organ injury and vascular injury. Complications are haemorrhage, malunion, nonunion, chronic pain, leg length discrepancy, sexual and urinary dysfunction, venous thromboembolism and infection.

Pathophysiology.

External rotation of the hemipelvis increases the pelvic volume, stretching the venous plexus and the branches of the internal iliac artery. About 80% of pelvic bleeding is venous and from fracture surfaces, and 10 to 20% is arterial (superior gluteal, internal pudendal).

Opening of the pelvic volume removes the tamponade effect, so haemorrhage continues into the retroperitoneal space, which can hold several litres.

Pain in the pelvis, inability to walk, leg rotation or length discrepancy, tenderness over the symphysis and sacroiliac joints, and bruising over the flank, perineum or scrotum (Destot sign). Blood at the urethral meatus, a high riding prostate or a vaginal or rectal laceration suggest urogenital or open injury.

Shock (tachycardia, hypotension, cool peripheries, falling urine output) with a pelvic injury signals pelvic haemorrhage until another source is excluded. Do not spring the pelvis, and avoid repeated log rolling. Assess lower limb pulses and the neurological state of the lumbosacral roots.

• Primary survey with immediate anteroposterior pelvic radiograph in the resuscitation area. Symphyseal diastasis and sacroiliac widening are the classic findings.
• Focused abdominal ultrasound (to find intraperitoneal blood), chest radiograph, and blood tests: haemoglobin, lactate, base deficit, coagulation, thromboelastography, group and crossmatch.
• CT with intravenous contrast (arterial and venous phases) when stable: the arterial blush indicates active arterial bleeding. Inlet and outlet views and CT define the fracture.
• Retrograde urethrogram before a urinary catheter when there is blood at the meatus, and CT cystography for bladder injury.

Differential diagnosis.

• Lateral compression pelvic fracture and vertical shear fracture.
• Acetabular fracture and pubic rami fracture.
• Hip dislocation and sacral fracture.
• Intra-abdominal, thoracic or long bone bleeding as the cause of shock, and pubic symphysis diastasis from pregnancy.

Resuscitation and haemorrhage control.

• Apply a pelvic binder centred on the greater trochanters (not the iliac crests) to any patient with a suspected unstable pelvic injury and shock, with the legs internally rotated and the feet taped together. Keep it on until definitive control in theatre. Do not spring the pelvis or log roll repeatedly.
• Two large bore intravenous lines (or intraosseous access). Permissive hypotension (systolic 80 to 90 mmHg) until bleeding is controlled, unless there is a head injury.
• Massive haemorrhage plan: red cells, plasma and platelets in a ratio of 1:1:1, adjusted to thromboelastography and laboratory results.
• Tranexamic acid 1 g intravenously over 10 minutes within 3 hours of injury, then 1 g intravenously over 8 hours (maximum 2 g in 24 hours). Reduce the dose in renal impairment (creatinine over 120 micromol/L). Monitor for seizures and thrombosis.
• Calcium chloride 10% 10 mL intravenously slowly after the first 4 units of red cells, then as needed to keep ionised calcium over 1.1 mmol/L (central or large proximal vein; monitor ionised calcium).
• Haemodynamically unstable despite the binder: preperitoneal pelvic packing or an anterior external fixator for damage control.
• Angioembolisation for arterial bleeding (a CT arterial blush or persistent shock after packing). Resuscitative endovascular balloon occlusion of the aorta (zone III) in selected patients.
• Anticoagulant reversal for warfarin: four factor prothrombin complex concentrate 25 units/kg (INR 2 to under 4), 35 units/kg (INR 4 to 6) or 50 units/kg (INR over 6), with vitamin K 5 mg intravenously slowly.
• Apixaban or rivaroxaban: andexanet alfa where available, or four factor prothrombin complex concentrate 50 units/kg. Dabigatran: idarucizumab 5 g intravenously.

Definitive fixation.

• APC I (stable): non-operative with analgesia and mobilisation with a walking aid as tolerated.
• APC II: symphyseal plating (3.5 mm plate with 4 to 6 holes through a Pfannenstiel approach) restores the pelvic ring, with or without iliosacral screw fixation.
• APC III: anterior symphyseal plating plus posterior fixation (iliosacral screws or sacroiliac plating) for the vertical instability.
• Open pelvic fracture or perineal wounds: debridement and faecal diversion with a colostomy for rectal injury, and suprapubic catheterisation for urethral injury.
• Weight bearing is restricted (toe touch to partial) for 6 to 12 weeks, then progressed with physiotherapy.

Open pelvic injury (wounds communicating with the perineum, vagina or rectum).

• Intravenous co-amoxiclav 1.2 g every 8 hours with metronidazole 500 mg intravenously every 8 hours (or cefazolin 2 g every 8 hours with metronidazole). Start within 1 hour of injury. Continue for 24 hours after definitive wound control and for no more than 72 hours.
• Maximum co-amoxiclav 3.6 g daily; every 12 hours at creatinine clearance 10 to 30 mL/min. Check liver tests, and reduce the metronidazole dose in severe hepatic impairment.
• For gross contamination add gentamicin 5 mg/kg intravenously once daily for up to 72 hours. Check creatinine daily and a level before the second dose. Avoid or extend the interval at eGFR under 60 mL/min/1.73 m2.
• With severe penicillin allergy use clindamycin 600 mg intravenously every 8 hours (maximum 2.7 g daily) with gentamicin.
• Tetanus booster 0.5 mL intramuscularly if the last dose was over 10 years ago. Add tetanus immunoglobulin 250 units intramuscularly (500 units if over 24 hours since injury or heavily contaminated) when immunisation is incomplete or unknown.

Operative antibiotic prophylaxis. Cefazolin 2 g intravenously (3 g when weight is 120 kg or over) within 60 minutes before incision as a single dose (repeat after 4 hours or blood loss over 1500 mL). With severe penicillin allergy, give vancomycin 15 mg/kg intravenously starting 90 to 120 minutes before incision as a single dose, with levels and creatinine checked in prolonged cases.

Thromboprophylaxis. Enoxaparin 40 mg subcutaneously once daily, started within 24 to 48 hours once bleeding is controlled and haemoglobin is stable. Continue for at least 28 days or until the patient is mobile. Use 20 mg once daily at creatinine clearance under 30 mL/min. Adjust by anti-Xa level in obesity and renal impairment. Check the platelet count on days 5 to 14 for heparin induced thrombocytopenia. Use mechanical prophylaxis until then.

Analgesia.

• Morphine 2.5 to 5 mg intravenously every 5 to 10 minutes as needed, titrated to pain. Halve the dose with age over 75, haemodynamic instability or eGFR under 30 mL/min/1.73 m2. Reassess after 10 mg. Monitor respiratory rate, oxygen saturation and blood pressure continuously.
• Paracetamol 1 g intravenously or orally every 6 hours (maximum 4 g daily; 3 g daily when weight is under 50 kg, with chronic alcohol use or hepatic impairment).
• Avoid ibuprofen in the acute phase because of bleeding and renal risk.
• After stabilisation, oral morphine 5 to 10 mg every 4 hours as needed for up to 5 days with a laxative.

Monitoring. Haemodynamics and lactate continuously; haemoglobin every 1 to 2 hours during resuscitation; urine output hourly. Pulses and neurological state of the legs every 4 hours in the first 24 hours. Radiographs after fixation, at 2 weeks, 6 weeks, 3 months and 12 months. Urinary, bowel and sexual function, leg length and gait at follow up.

Referral and escalation. Emergency: activate the trauma team on suspicion of an unstable pelvic injury. Early involvement of orthopaedics, interventional radiology and urology, with transfer to a major trauma centre. Escalate for shock after binder application, open wounds, or expanding perineal or flank haematoma.

Special groups.

• Pregnancy: left lateral tilt of 15 degrees, early obstetric input, foetal monitoring when over 24 weeks, and anti-D immunoglobulin in rhesus negative women with a Kleihauer test.
• Children: the elastic pelvis tolerates energy and can hide a serious injury; associated visceral injuries are frequent.
• Older adults: low energy mechanisms occur with anticoagulation, so check anticoagulant status early.
• Kidney impairment: reduce tranexamic acid dose, avoid ibuprofen and extend gentamicin intervals.