Vertical Shear Pelvic Fracture

Vertical shear (VS) pelvic fracture is a pelvic ring injury in which a vertical force through the femur displaces the hemipelvis upward and backward, with complete disruption of the anterior and posterior arches and the pelvic floor ligaments (sacrospinous and sacrotuberous). It is rotationally and vertically unstable.

It follows a fall from height landing on one leg, or a vehicle collision with the extended leg braced. It accounts for about 5% of pelvic ring injuries. Haemorrhage can be severe, and associated injuries are common.

The pattern is a sacroiliac dislocation, a transsacral fracture or an iliac fracture, combined with symphyseal or rami disruption. A vertical displacement of the hemipelvis of over 1 cm indicates the injury.

Associated injuries are lumbosacral plexus injury (L5 and S1), urethral and bladder injury, vascular injury, spinal fractures and intra-abdominal organ injury. Complications are haemorrhage, malunion, nonunion, leg length discrepancy, chronic pain, nerve deficit, sexual and urinary dysfunction, venous thromboembolism and infection.

Pathophysiology.

Axial load through the femur drives the hemipelvis cranially. The posterior sacroiliac and iliolumbar ligaments and the pelvic floor all fail, which allows displacement in all planes.

The pelvic binder controls rotation but not vertical displacement. Skeletal traction helps to reduce vertical displacement and reduces the pelvic volume.

Pelvic pain, inability to move the leg, leg shortening with external rotation on the injured side, perineal and flank bruising, and lower limb neurological deficit. Shock is common. Look for blood at the meatus, a vaginal or rectal laceration (open fracture), and abdominal tenderness.

Do not spring the pelvis, and avoid repeated log rolling.

• Anteroposterior pelvic radiograph: vertical displacement of the hemipelvis (over 1 cm), sacroiliac disruption, and fractures of the sacral foramina or transverse processes of L5.
• CT with intravenous contrast (arterial and venous phases): fracture detail and the arterial blush. Inlet and outlet views.
• Haemoglobin, lactate, base deficit, coagulation, thromboelastography and group and crossmatch.
• Retrograde urethrogram when there is blood at the meatus, and CT cystography for bladder injury.
• Lumbosacral plexus and sacral root examination, and later electromyography.

Differential diagnosis.

• Open book and lateral compression pelvic fractures.
• Acetabular fracture and sacral fracture with spinopelvic dissociation.
• Hip dislocation and lumbar fracture.
• Intra-abdominal or thoracic bleeding as the cause of shock.

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. The binder does not control vertical displacement.
• 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 (CT arterial blush or persistent shock after packing), and 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.
• Anticoagulant reversal for apixaban or rivaroxaban: andexanet alfa where available, or four factor prothrombin complex concentrate 50 units/kg. For dabigatran: idarucizumab 5 g intravenously.

Skeletal traction. Use a distal femoral or proximal tibial traction pin with traction weights of about 10 to 15 kg (adjusted to the radiographic reduction and body weight). Apply early and maintain until posterior fixation. Check pin sites daily. Traction is not used with an ipsilateral femoral or acetabular fracture that prevents it.

Definitive fixation (when physiologically stable).

• Posterior fixation of the sacroiliac joint or sacral fracture: iliosacral screws (7.0 mm cannulated), sacroiliac plating, transiliac plates, or lumbopelvic fixation for transforaminal sacral fractures with spinopelvic instability.
• Anterior fixation: symphyseal plating (3.5 mm plate) or rami fixation, or an external fixator.
• Nerve decompression of sacral foramina when there is a progressive deficit.
• Non-weight bearing on the injured side for 12 weeks, then progressive loading 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.
• Co-amoxiclav maximum 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.
• Faecal diversion for rectal injury.

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. Check levels and creatinine 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 mechanical prophylaxis until then.

Give 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.

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.
• Neuropathic pain from plexus injury: gabapentin 300 mg orally at night, increased by 300 mg every 1 to 3 days to 300 to 600 mg three times daily (maximum 1800 mg daily; reduce at creatinine clearance under 60 mL/min). Monitor sedation and dizziness.

Monitoring. Haemodynamics and lactate continuously; haemoglobin every 1 to 2 hours during resuscitation; urine output hourly. Pulses and lower limb neurology every 4 hours in the first 24 hours. Radiographs after fixation, at 2 weeks, 6 weeks, 3 months and 12 months, with measurement of residual vertical displacement. Leg length, gait, nerve recovery, and urinary and sexual function at follow up.

Referral and escalation. Emergency: activate the trauma team and involve orthopaedics, interventional radiology and urology early. Transfer to a major trauma centre. Escalate for shock after binder application, open wounds, expanding perineal or flank haematoma, or progressive neurological deficit.

Special groups.

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