Trauma
Question 27 of 216
A 13 year old boy presents to the Emergency Department with pain to the left lateral upper thigh. The pain is worse on movement. He describes the onset of pain during a football game and describes feeling a "give" when he kicked the ball. He is unable to weight bear. A pelvic radiograph is obtained and based on the findings your Consultant diagnoses an avulsion fracture caused by the rectus femoris muscle. What structure is fractured?
Answer:
Forceful contraction of the rectus femoris (as in kicking a ball) can result in an injury of anterior inferior iliac spine avulsion. The ischial tuberosity may be avulsed during strenuous contraction of the hamstrings. A portion of the iliac crest epiphysis may be avulsed by contraction of the abdominal muscles. The anterior superior iliac spine may be avulsed by forcible contraction of the sartorius muscle.Pelvic Trauma
Trauma
Last Updated: 13th February 2021
Pathophysiology
Pelvic fractures associated with haemorrhage commonly involve disruption of the posterior osseous ligamentous complex (i.e. sacroiliac, sacrospinous, sacrotuberous, and the fibromuscular pelvic floor) evidenced by a sacral fracture, a sacroiliac fracture, and/or dislocation of the sacroiliac joint. Disruption of the pelvic ring tears the pelvic venous plexus and occasionally disrupts the internal iliac arterial system.
Mortality in patients with all types of pelvic fractures is approximately one in six, rising to approximately one in four in patients with closed pelvic fractures and hypotension and approximately one in two in patients with open pelvic fractures. Haemorrhage is the major potentially reversible contributing factor to mortality. Unexplained hypotension may be the only initial indication of major pelvic disruption. Mechanical instability of the pelvic ring should be assumed in patients who have pelvic fractures with hypotension and no other source of blood loss. Placement of a pelvic binder is a priority and may be lifesaving in this circumstance.
Mechanism of injury
Pelvic ring injuries can occur following a:
- Motor vehicle crash
- Motorcycle crash
- Pedestrian-vehicle collision
- Direct crushing injury
- Fall
Classification:
- AP compression (open book) injury: 15 - 20% frequency
- This type of injury is often associated with a motorcycle or head-on motor vehicle crash.
- This mechanism produces external rotation of the hemipelvis with separation of the hemipelvis and tearing of the posterior ligamentous complex. The disrupted pelvic ring widens, tearing the posterior venous plexus and branches of the internal iliac arterial system.
- Haemorrhage can be severe and life threatening.
- Lateral compression injury: 60 - 70% frequency
- This involves force directed laterally into the pelvis and is the most common mechanism of pelvic fracture in a motor vehicle collision.
- In contrast to AP compression, the hemipelvis rotates internally during lateral compression, reducing pelvic volume and reducing tension on the pelvic vascular structures. This internal rotation may drive the pubis into the lower genitourinary system, potentially causing injury to the bladder and/or urethra.
- Haemorrhage and other sequelae from lateral compression injury rarely result in death, but can produce severe and permanent morbidity, and elderly patients can develop significant bleeding from pelvic fractures from this mechanism. When this occurs, these patients require early haemorrhage control techniques such as angioembolisation. Frail and elderly patients may bleed significantly following minor trauma from lateral compression fractures.
- Vertical shear: 5 - 15% frequency
- Vertical displacement of the sacroiliac joint can also disrupt the iliac vasculature and cause severe haemorrhage.
- In this mechanism, a high-energy shear force occurs along a vertical plane across the anterior and posterior aspects of the ring. This vertical shearing disrupts the sacrospinous and sacrotuberous ligaments and leads to major pelvic instability.
- A fall from a height greater than 12 feet commonly results in a vertical shear injury.
- Combination pattern
Assessment
- Identify mechanism of injury which can suggest the possibility of pelvic fracture
- Inspect for signs of pelvic fracture:
- Signs of urethral injury:
- Ecchymosis or haematoma of the scrotum or perineum
- Blood at the urethral meatus
- Gross haematuria
- Signs of pelvic-ring instability:
- Lower limb neurological deficit
- Open wounds in the flank, perineum, vagina or rectum
- Unexplained hypotension may be the only initial indication of major pelvic disruption
- Discrepancy in limb length
- Rotational deformity of the leg
- Ecchymosis over the iliac wings, pubis, labia or scrotum
- Bony tenderness of the bony pelvis
- Signs of urethral injury:
- Perform a rectal exam noting:
- Quality of sphincter tone
- Rectal mucosal integrity
- Position and mobility of the prostate gland
- Any palpable fracture
- Presence of blood
- Perform a vaginal exam (when injury is suspected) noting:
- Any palpable fractures
- Vaginal mucosal integrity
- Presence of blood
- Distraction of the pelvis is not recommended during the early assessment of injuries because it may worsen or cause recurrent pelvic bleeding.
- An anteroposterior (AP) x-ray of the pelvis is a useful adjunct to identify a pelvic fracture, given the limitations of clinical examination.
- Check for interruption of the arcuate and ilioischial lines, including the pubic symphysis. The pubic symphysis should be less than 1 cm in pregnancy and less than 0.5 cm in nonpregnant adults.
- Check for widening or displacement of the sacroiliac joints. Check the transverse processes of L5 because they may fracture with sacroiliac disruption.
- Check the sacrum for evidence of fracture. The arcs of the foramina may be interrupted with sacral fractures.
- Check the acetabulum bilaterally for interruption and femoral dislocation. Check the femoral head and neck for disruption bilaterally.
- Perform urinary catheterisation:
- A urinary catheter placed during resuscitation will relieve retention, identify bleeding, allow for monitoring of urinary output as an index of tissue perfusion, and decompress the bladder before DPL (if performed).
- A full bladder enhances the pelvic images of the FAST. Therefore, if FAST is being considered, delay placing a urinary catheter until after the test is completed.
- A retrograde urethrogram is mandatory when the patient is unable to void, requires a pelvic binder, or has blood at the meatus, scrotal haematoma, or perineal ecchymosis.
- To reduce the risk of increasing the complexity of a urethral injury, confirm an intact urethra before inserting a urinary catheter.
- A disrupted urethra detected during the primary or secondary survey may require insertion of a suprapubic tube by an experienced doctor.
Management
- Initial management of hypovolemic shock associated with a major pelvic disruption requires rapid haemorrhage control and fluid resuscitation. Haemorrhage control is achieved through mechanical stabilisation of the pelvic ring and external counter pressure. Patients with these injuries may be initially assessed and treated in facilities that do not have the resources to definitively manage the associated haemorrhage. In such cases, trauma team members can use simple techniques to stabilise the pelvis before patient transfer.
- The mechanically unstable hemipelvis migrates cephalad because of muscular forces and rotates outward secondary to the effect of gravity on the unstable hemipelvis. External rotation of the unstable pelvis results in an increased pelvic volume that can accommodate a larger volume of blood. Therefore internal rotation of the lower limbs may assist in haemorrhage control by reducing pelvic volume.
- By applying a support directly to the patient’s pelvis, clinicians can splint the disrupted pelvis and further reduce potential pelvic haemorrhage. A sheet, pelvic binder, or other device can produce sufficient temporary fixation for the unstable pelvis when applied at the level of the greater trochanters of the femur. External pelvic binders are a temporary emergency procedure. Proper application is mandatory, and patients with pelvic binders require careful monitoring. Tight binders or those left in position for prolonged time periods can cause skin breakdown and ulceration over bony prominences.
- In cases of vertical shear injuries, longitudinal traction applied through the skin or the skeleton can also assist in providing stability. This should be done with the consultation of an orthopaedic specialist.
- Optimal care of patients with haemodynamic abnormalities related to pelvic fracture demands a team effort of trauma surgeons, orthopaedic surgeons, and interventional radiologists or vascular surgeons. Angiographic embolisation is frequently employed to stop arterial haemorrhage related to pelvic fractures. Preperitoneal packing is an alternative method to control pelvic haemorrhage when angioembolisation is delayed or unavailable.
- Haemorrhage control techniques are not exclusive and more than one technique may be required for successful haemorrhage control. An experienced trauma surgeon should construct the therapeutic plan for a patient with pelvic haemorrhage based on available resources.
- Significant resources are required to care for patients with severe pelvic fractures. Early consideration of transfer to a trauma center is essential. In resource limited environments, the absence of surgical and/or angiographic resources for haemodynamically abnormal patients with pelvic fractures or haemodynamically normal patients with significant solid organ injury mandates early transfer to a trauma center with these facilities.
Other types of fracture
- Isolated pubic ramus fractures
- Common and often missed in the elderly (particularly when the focus is on a potential fractured neck of femur). Refer to orthopaedics/elderly care team for analgesia, initial bed rest, and then mobilisation.
- Avulsion fractures around the pelvis
- Avulsion fractures occur at attachments of various muscles as follows:
- Anterior inferior iliac spine— rectus femoris (typically results from a miskick into the turf
- Anterior superior iliac spine— sartorius
- Ischial tuberosity— hamstrings
- In most instances, symptomatic treatment based upon rest (consider crutches) and analgesia suffices. Larger avulsions (particularly of the ischial tuberosity) may require internal fixation (to avoid complications such as non- union).
- Avulsion fractures occur at attachments of various muscles as follows:
- Fractures of the sacrum
- Usually follows violent direct trauma such as falls.
- Damage to sacral nerve roots may occur. Check carefully for saddle anaesthesia, decreased anal tone, lower limb weakness, or bladder dysfunction.
- Refer to the orthopaedic team.
- Fracture of the coccyx
- Follows a fall onto the bottom.
- Do not X- ray routinely— the diagnosis is clinical. Perform a PR examination, and check for local coccygeal tenderness, palpable fractures, or rectal damage.
- Complications are unusual, but refer patients with rectal tears to the general surgeon and refer to the orthopaedic team if the coccyx is grossly displaced, as it may require manipulation under LA or even excision. Treat the rest (the majority) symptomatically (e.g. suggest a ring cushion and provide analgesia).
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
