Pelvis and Hip

Question 1

Assess AP Pelvis Image

• (rings?)
• (SI joints?)
• (Pubic symphysis

Answer 1

• the main pelvic ring: inner and outer cortices
• two small rings: obturator foramina
• SI joints - widths shold be equal
• Superior surfaces of each pubic bone should align
• Acetabulum
• sacral foramina should be a smooth curve

COMPARE BOTH SIDES

Question 2

Fractures Of Pelvis

Answer 2

• Widening (diastasis) of the pubic symphysis or at teh SI joint is classed as a break in the main pelvic ring
• # at one side of the ring is likely associated with # or ligamentous damage at a second site
• double break in the pelvic ring is an unstable injury
• actabular # are commonly comminuted and fragments can get trapped in the joint space

Question 3

Avulsion of Apophysis

Answer 3

• commonly caused by repeated or sudden and violent muscle contraction in young people
• healing may produce a lot of calcification, may look lucent/moth-eaten at pain site: CAN BE MISTAKEN FOR BONE INFECTION OR CANCER

Question 4

AP Pelvis Positioning

Answer 4

• Patient lies supine on the bed, hands placed on chest. heels separated, toes touching
• Iliac crests should be equidistant from the bed
• Centre midway between ASIS, midway between ASIS and symphysis pubis
• collimate to inclue iliac crests and proximal femur to include both lesser trochanters. Laterally include all of the greater trochanters and edge of crests
• Use a grid
• 81kVp 20mAs (AEC is used)

CHECK LMP - 28 DAY RULE 12-55yo

Question 5

AP Pelvis Positioning

Answer 5

• Patient lies supine on the bed, hands placed on chest. heels separated, toes touching
• Iliac crests should be equidistant from the bed
• Centre midway between ASIS, midway between ASIS and symphysis pubis
• collimate to inclue iliac crests and proximal femur to include both lesser trochanters. Laterally include all of the greater trochanters and edge of crests
• Use a grid
• 81kVp 20mAs (AEC is used)

CHECK LMP - 28 DAY RULE 12-55yo

Question 6

Hip Fractures

• (what to look for?)
• (types of hip #?)

Answer 6

• is there a step in the cortical margins of the femoral neck?
• is the trabecular pattern continous?
• is there a dense/sclerotic white line (compression or impaction) across the femoral neck?

Acetabular and pubic rami # can have similar symptoms of a NOF #

• subcapital #
• transcervical #
• intertrochanteric #
• subtrochanteric #

Question 7

Hip Dislocations

• (most common type?)
• (associated risks?)
• (simple vs complex?)

Answer 7

• 80% of hip dislocations are posterior
• results from high impact trauma
• # of acetabular rim are common with hip dislocations
• avascular necrosis is an associated risk
• simple: just dislocation; complex: dislocation and # of acetabulum of proximal femur
• posterior dislocation: slight flexion, internal rotation- FEMORAL HEAD SUPERIMPOSES ROOF OF ACETABULUM
• anterior dislocation: leg in extension, external roation- FEMORAL HEAD INFERIOR OF ACETABULUM

Question 8

Lateral Hip Positioning

Answer 8

• patient is rolled 45 deg towards sore hip (from lying supine on bed). Knee on affected side is bent, angled pad placed behind hip
• centre over the femoral head (in the groin), midway between the ASIS and the pubic symphysis
• collimate to include anterior/posterior skin margins, superiorly to include the whole acetabulum, inferiorly to get proximal 1/3 of femur
• LMP NEEDS TO BE CHECKED
• 75KvP 15mAs (AEC is used)

Question 9

AP Femur Positioning

Answer 9

• may need to do hip down and then knee up images in order to get onto the detector
• important to inlcude one full joint on each image rather than half of two joints on one image
• patient lies supine on the bed
• hells separate, toes touching
• centre midshaft of femur
• collimate to include ASIS to below knee joint
  
  • if two images, ensure there is overlap of the midshaft
• 77kVp 8mAs
• grid used for hip down image
• CHECK LMP 12-55

Question 10

Lateral Femur Positioning

Answer 10

• patient is rolled 45 deg to affected side (from supine)
• knee on affected side is flexed, angled pad placed behind back
• femoral condyles should be superimposed over one another
• centre midshaft
• collimate to include distal aspect of knee joint, ASIS and anterior and posterior skin margins
• if doing two images, ensure there is overlap in midshaft
  77kVp 8mAs
• grid is used (not on knee up image)
  CHECK LMP