Acute Pelvis & Hip Trauma Imaging Diagnosis Part I

Unstable Fx: a result of high energy trauma with >50% d/t MVA
20% closed Fx and 50% of open Fx result in mortality
Mortality is associated with vascular and internal organs injuries
Vascular injury: 20% arterial 80% venous
Chronic morbidity/disability and prolonged pain
Unstable Fx are rarely seen in the outpatient setting and typically and present to the ED
Stable pelvic Fx are usually caused by muscles/tendons avulsions and more often seen in pediatric cases

The bony pelvis is a continuous ring of bone held by strong ligaments
During significant impact, pelvic fractures may occur in more than one location because forces applied to one region of the ring will also correspond to injury on the other, usually the opposite side of the ring (above image)
Thus the majority of unstable pelvic Fx will typically demonstrate more than one break

Pelvic is seen as a ring of bone connected by some of the strongest ligaments in the body
The pelvic ring comprises 2-semirings: anterior to the acetabulum and posterior to the acetabulum
The bony pelvis is in close proximity to major vessels carrying a greater chance of vascular injury

Standard AP Pelvis (above images)
Judet views evaluating the acetabulo-pelvic region
Inlet/Outlet views helping with the symphysis and SIJ regions
Rad survey of the pelvis should include evaluation of the continuity of pelvic rings:
Inlet/outlet, obturator rings (above the first image)
Symphysis pubis and SIJ for diastasis and post-trauma separation (above the second image)
Lumbosacral spine and hips should also be carefully examined

Iliopectineal, ilioischial, Shenton and Sacral arcuate lines will help detection of sacral, acetabular and hip fracture/dislocations

Appreciating anatomical sites of pelvic origin/insertion of different muscles will help Dx of pelvic avulsion Fx

Avulsion Fx of the AllS (origin of the direct head of Rectus femoris M)
Pelvic avulsions occur by sudden eccentric contraction especially during kicking or jumping
Imaging: x-radiography will suffice
Clinically: sudden snap or pop followed by local pain. Pt can weight bear
Care: non-operative with rest for 4-weeks. Non-union is rare. No major complications
DDx: key rad DDx feature is not to mistake an avulsion from an aggressive pediatric bone tumor-like osteosarcoma that may show some exuberant new bone formation d/t healing and bone callus

Malgaigne Fx: d/t vertical shear injury to the ipsilateral pelvis
Rad Dx: ipsilateral superior and inferior pubic rami Fx (anterior ring) with ipsilateral SIJ separation/Fx of the sacrum and adjacent ilium (posterior ring). Symphysis pubis diastasis can be seen. An additional clue is an avulsion of L4 and/or L5 TP that often signifies serious pelvic injury
Clinically: marked leg shortening, shock, inability to weight bear.
Damage to Superior Gluteal Artery can occur
Imaging: x-radiography followed by CT scanning w/o and with IV contrast esp. if visceral injury present
Care: surgical in most cases d/t significant instability. ORIF. Hemostasis, Pelvic stabilization
Prognosis: depends on the complexity, rate of visceral complications and stability. 10% Superior glut artery bleed requiring rapid hemostasis

Mechanism: AP compression of different force magnitude (picture depiction)
Rad Dx: diastasis of symphysis pubis with diastasis of SIJ with and w/o adjacent Fx of the ala
Imaging steps: x-radiographic, CT scanning with and w/o contrast for vascular injury, cystography for acute urinary bladder rupture
Immediate and delayed complications may occur: vascular injury, urethral/bladder injury

Mechanism: direct impact/collision
High risk of urinary bladder/urethral injury
Imaging: bilateral superior and inferior pubic rami Fx with or w/o diastasis and Fx of SIJ
CT with and w/o contrast for vascular injury
Cystourethrogram additionally evaluates a urogenital injury
Complications: urethral strictures, bleeding, bladder rupture
Note: Straddle Fx with right SIJ separation

Common injury
Occurs in:
1) Young adults due to high energy trauma
2) Osteoporotic patients with low impact, trivial or no trauma (i.e., insufficiency Fx)
X-radiography is crucial to early Dx and prevention of complications which include:
Dx: intra-capsular vs. extra-capsular Fx
Ischemic osteonecrosis aka avascular necrosis (AVN) of the femoral head and rapid disabling DJD
Epidemiology: USA has some of the highest rates of OSP hip Fx worldwide. Highest healthcare cost Fx to treat overall
Women>men, Caucasians>African-Americans
25-30% mortality within the 1st year. Mortality depends on co-morbidities and stat of activity prior Fx
Pathophys: the femoral neck is intra-capsular and transmits arterial flow to the head. The neck is uncovered by the periosteum and unable to develop a good callus. The neck transmits maximum tensile forces through the proximal femur and prone to Fx and non-union

Acute Pelvis & Hip Trauma