Lecture 7: Pelvis, Hip, Knee, Ankle, Foot

AP view of pelvis main observations

- architecture should be symmetrical

- iliofemoral line

- ilioischial line

- iliopectineal line

- radiographic tear drop

- figure 8/crossover sign

why do we take AP view instead of PA view of the pelvis?

the sacrum is enlarged when it's taken in a PA view

patient positioning of AP view of hip

15 degrees of IR

AP view hip lines

- femoral head of acetabulum

- femoral head

- shenton's hip line

- iliofemoral line

- femoral neck angle

lateral (frog-leg) view of hip patient positioning

hip flexed, ABD, ER

con of lateral frog-leg view of hip

a lot of distortion

diagnostic imaging for low energy injuries of the pelvis and hip

- AP pelvis to locate injuries

- oblique view of pelvis: "judet view" to demonstrate the columns of the acetabulum free of superimposition

- CT used in dx of fracture in areas

diagnostic imaging for high energy injuries of pelvis and hip

CT scans --> "TAP" series (thorax, abs, pelvis)

characteristics of fractures of the pelvis

- MOI: typically MVA or crash

- classifications: based on stability of pelvic ring

- stable vs. unstable fractures

- AP view imaging

treatment for stable fractures of pelvis

full function may require 6-12 weeks

treatment for unstable fractures of the pelvis

internal or external fixation and/or skeletal traction

complications of fractures of the pelvis

- mortality rate from pelvis fracture 5-15%

- acute hemorrhage or visceral damage

fractures of the acetabulum imaging

- difficult to evaluate with AP view due to superimposition of femoral head

- usually will do anterior and posterior oblique projections

fractures of the acetabulum MOI

- impaction of femoral head into the acetabulum

- posterior vs. anterior displacement of acetabulum

classification of fractures of the acetabulum

- anatomic position

- anterior: iliopubic area

- posterior: ilioischial area

- transverse: both columns

fractures of the proximal femur incidence

- 72 y/o for males, 77 y/o for females

- mild to severe osteoporosis

classification of fractures of the proximal femur

- intracapsular fractures

- extracapsular fractures

- fixation failure

types of intracapsular fractures of proximal femur

- femoral head fracture

- subcapital fracture

- femoral neck fracture

types of extracapsular fractures of proximal femur

- intertrochanteric fracture

- subtrochanteric fracture

- shaft fracture

radiologic findings of OA/degenerative joint disease

- sclerotic subchondral bone

- osteophyte formation

- asymmetrical joint space narrowing

- cyst or pseudocyst formation

- migration of the femoral head

rheumatoid arthritis

progressive, systemic, autoimmune inflammatory disease primarily affecting synovial joints

radiologic findings of RA

- symmetrical joint space narrowing

- axial migration of femoral head

- acetabular protrusion

- femoral head becomes distorted

avascular necrosis

result of interruption of blood supply to the femoral head resulting in bone death

legg-calve-perthes

avascular necrosis in 4-10 y/o

radiologic signs of avascular necrosis

- crescent sign

- joint space is typically maintained in early stages, but sclerosis and cyst formation

- femoral head collapse

slipped capital femoral epiphysis (SCFE)

- weakening of the physeal plate at the junction of the femoral neck and dead allows the head to displace

- unknown etiology

- posteromedioinferior displacement of the proximal femoral epiphysis

- clinical presentation: 10-16 y/o

- radiologic findings: frog leg view will show how much displacement

femoroacetabular impingement (FAI)

overcoverage of the acetabular rim or an irregular shaped femoral head/neck junction

FAI types

- CAM: pistal grip deformity

- Pincer: cross over or figure 8 sign

AP view of the knee observations

- patella superimposed

- joint space is visible and equal in height

- long axes of femur and tibia in alignment

lateral view of the knee patient positioning

medial to lateral, with 20 degrees of flexion

lateral view of the knee observations

- medial condyle superimposed

- suprapatellar bursa

- fabella

- assessment of patella (insall-salvati ratio) aka patella alta/baja

tunnel or notch view of knee patient positioning

prone, 40 degrees of knee flexion

tunnel or notch view of knee is used to assess

- loose bodies in the joint

- osteochondral defects

- narrowing of the femorotibial joint space

sunrise view/tangential view of patellofemoral joint patient positioning

- supine with knee flexed to 45 degrees

- can take in two ways: superoinferior direction or inferosuperior direction

angles with sunrise view of knee

- sulcus angle: 138 +/- 6

- congruence angle: -6, patella position at +16

ottawa rules for indications for imaging

- age > 55 y/o

- isolated patellar tenderness w/o other bone tenderness

- tenderness of the fibular head

- inability to flex the knee to 90 degrees

- inability to bear weight immediately after injury and in the emergency department (4 steps) regardless of limping

segond fracture

- small avulsion fracture at the lateral tibial plateau

- due to ACL tear or other injuries

- IR and varus stress at the knee

patellar fractures

- MOI: falls, dashboard impacts

- radiologic evaluation: tangential and lateral views

tibial plateau fractures

- car-pedestrian

- radiologic evaluation: AP and lateral views, FBI sign in CT and MRI

- treatment: non-WB

distal femur fractures MOI

- high energy

- decrease bone strength

distal femur fractures classifications

- supracondylar

- intercondylar

- condylar

apophyseal defects of knee

- osgood schlatters

- sindig larsen johansson

signs of OA of the knee

- decrease joint space

- sclerosis of subchondral bone

- osteophyte formation

- subchondral cyst

- valgus or varus deformit

varus OA of knee

medial joint line compression

valgus OA of knee

lateral joint line compression

mortise view of ankle patient positioning

15-20 degrees inversion

mortise view of ankle observations

- 3-4 mm width space in mortise

- > 6mm spread of distal tibfib joint

lateral view of the foot: boehler/bohler/salient angle

- relationship of talus and calcaneus post trauma

- 25-40 degrees

lateral view of the foot: calcaneal pitch

- 20-30 degrees

- 50+ = pes cavus

- < 20 = pes planus

ottawa ankle rules for indications for imaging

- bony tenderness along distal 6 cm of posterior edge of fibular or tip of lateral malleolus

- bony tenderness along distal 6 cm of posterior edge of tibia/tip of medial malleolus

- bony tenderness at the base of 5th metatarsal

- bony tenderness at the navicular

- inability to bear weight both immediately after injury and for 4 steps during initial evaluation

unimalleolar fracture of the ankle

one of the malleoli are fractures

bimalleolar fracture of the ankle

both malleoli are fractured

trimalleolar fracture of the ankle

both malleoli and the posterior rim of the tibia are fractured

maisonneuve fracture of the ankle

- proximal spiral fracture of the fibula

- distal tib fib joint instability

lisfranc injury

fracture or dislocation of lisfranc joint (connects bones of midfoot to the base of toes

fractures of 5th MT

- avulsion: base of 5th MT

- jones: proximal shaft of 5th MT

- stress: distal to jones fracture