Mechanism of injury—fall or minor trauma
Usually older age group
Fractures of individual bones or single break in pelvic ring
Minor fractures account for 25% of pelvic fractures
Common minor fractures
Avulsion fractures (Fig. 3-1)
Traumatic and apophyseal in adolescents
Pathologic in the older age group
Pubic rami fractures
Transverse sacral fractures (up to 70% missed on routine radiographs)
Complications—pain, rarely significant complications compared with complex fractures
FIGURE 3-2. (A) Anteroposterior (AP) radiograph of the pelvis demonstrating a left ischial tuberosity avulsion fracture (black arrow). (B) Axial T1-weighted magnetic resonance (MR) image of the same patient redemonstrates the fracture (white arrow).
Mechanism of injury—minor trauma
Usually nondisplaced pubic rami fractures involving one side
Account for approximately one-third of pelvic fractures
Complications—pain, local hematoma
Magnetic resonance (MR) may detect unsuspected posterior ring injuries
Mechanism of injury—high-velocity trauma, such as a motor vehicle accident
Lateral compression (41% to 72% of cases)
Anteroposterior (AP) compression (15% to 25% of cases)
Vertical shearing injuries (6% of cases)
Combined mechanisms (14% of cases)
Two or more breaks in the pelvic ring
Occur in younger age group (52% are less than 30 years of age)
Complications may be severe 100% result from multiple complications.” class=HASTIP>*
Other associated fractures
Additional imaging, specifically computed tomography (CT), is usually required to define extent of injury
Mechanism of injury—lower extremity trauma with force directed to the femoral head.
Fractures involve posterior acetabulum if hip flexed. Posterior dislocation may occur.
Transverse and anterior fractures occur with lateral blow to greater trochanter.
AP and Judet views may detect injury. CT with coronal and sagittal reformatting is useful to evaluate and characterize subtle fractures and the joint space involvement.
Complications—minor, or arthrosis in later years.
Multiple fracture classification systems have been proposed.
Two-column, transverse with posterior wall involvement, and posterior wall fractures account for 66% of acetabular fractures. “T” and transverse fractures are the next two most common injury patterns. These five patterns account for 90% of acetabular fractures.
Definition of extent of articular and anterior and posterior column involvement is critical for treatment planning.
CT with reformatting in sagittal and coronal planes, or three-dimensional volume rendering, or shaded surface display is essential.
Complications are similar to complex pelvic fractures (see section on Pelvic Fractures—Complex).
Hip dislocations account for 5% of all skeletal dislocations.
Mechanism of injury—high-velocity trauma, usually in young adults
Posterior dislocations—10 times more common than anterior. Compressive force to foot or knee with hip flexed. Posterior acetabular fractures are common.
Anterior dislocations—forced abduction and external rotation. Femoral head and anterior acetabular fractures are common.
Up to 75% have multiple other injuries.
Most complete dislocations are obvious on the AP view of pelvis or involved hip.
CT is useful for complete evaluation of the joint space and associated fractures, especially after reduction.
Occur in the elderly and in females more than in males
Mechanism of injury—minimal trauma or fall
Type I: incomplete involving lateral cortex
Type II: complete, but undisplaced
Type III: partially displaced
Type IV: completely displaced
Some prefer undisplaced (Types I and II) and displaced (Types III and IV)
Imaging of subtle undisplaced fractures may require magnetic resonance imaging (MRI) for detection. Displaced fractures usually are obvious on routine radiographs
Mortality: 10% to 20% in the first 30 days after injury and surgery
Mortality: approximately 30% first year after injury
Avascular necrosis (AVN) is common with displaced fractures
Treatment—pin undisplaced and endoprostheses used for displaced fractures because of high incidence of AVN
FIGURE 3-14. (A) Anteroposterior (AP) right hip radiograph demonstrates an impacted femoral neck fracture (black arrows) with cortical disruption and trabecular compression laterally. (B) Treated by percutaneous pinning.
FIGURE 3-15. (A) Displaced femoral neck fracture (black arrows). (B) Treated with bipolar hemiarthroplasty. Note the prior right femoral neck fracture treated by percutaneous pinning.
Three types of fracture: avulsion, intertrochanteric, and subtrochanteric
Most common in elderly because of falls
Extracapsular; comminution of fracture with detachment of trochanters common
Significant mortality (18% to 30%) in year of injury
More common in younger patients with high-velocity trauma
Can be associated with chronic bisphosphonate treatment
Reduction more difficult to maintain than intertrochanteric fractures
Caused by abrupt muscle contraction (Fig. 3-17)
Occur in active athletes
Greater trochanteric avulsions also seen in elderly patients
Routine radiographs usually are diagnostic
FIGURE 3-18. Anteroposterior (AP) pelvic radiograph of a comminuted intertrochanteric femur fracture (black arrows) angular deformity (coxa vara deformity).
Insufficiency fractures occur because of normal stress on bone with abnormal elastic resistance.
Insufficiency fractures most commonly involve the sacrum, pubic rami, and supra-acetabular regions and femoral necks.
Most insufficiency fractures occur in elderly osteopenic patients or patients on steroid therapy.
Patients present with back, hip, or groin pain.
Radiographs: Bone sclerosis or condensation, typically linear.
Radionuclide scans: Increased tracer in area of fracture. Bilateral sacral fractures give “H” appearance (Honda sign).
MRI: Marrow edema pattern with or without visible fracture line.
CT: Fracture lines clearly defined.
Soft tissue injuries to the pelvis, hips, and thighs may include
Acetabular labral tears
Snapping tendon syndromes
Greater trochanteric pain syndrome
Imaging approaches vary with suspected clinical condition
MRI or MR arthrography of the hip for intra-articular hip pathology
Acetabular labral tears
MR arthrography of the hip
Ultrasound or MRI
Snapping tendon syndrome
Tendon injection with motion studies, ultrasound
MR, magnetic resonance; MRI, magnetic resonance imaging.
Muscle/tendon tears are common in athletes and patients engaged in exercise programs.
Underlying disorders (diabetes mellitus, steroid therapy, connective tissue diseases, and renal failure) may also lead to myotendinous injuries.
Categories of injury
Grade 1 strain: a few fibers torn
Grade 2 strain: approximately 50% of fibers torn
Grade 3 strain: complete tear
Muscles involved include the hamstrings, adductors, gluteal, iliopsoas, and abdominal muscles.
Radiographs or CT is useful for avulsion injuries or myositis ossificans.
MRI is superior for the detection and staging of injuries.
FIGURE 3-22. Axial (A) and sagittal (B) T2-weighted fat-suppressed images of a Grade 2 strain of the rectus femoris. (A) The muscle edema is centered at the myotendinous junction (white arrow). (B) Feathery edema extends through the muscle fibers (black arrows) with a small anterior hematoma (white arrow).Premium Wordpress Themes by UFO Themes
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