Ch 11 Hips Flashcards
What are the 2 pathologies we cover regarding ped hips?
-Hip effusion (transient synovitis + septic arthritis)
-Developmental dysplasia
The hip joint is composted of the ___ + the ___?
Pelvic girdle + femur
The hip bone (aka pelvic girdle) is composed of what 3 structures?
Ilium, ischium + pubis
___ is the socket of the hipbone into which the femur head fits?
Acetabulum
___ is a lip of cartilage that sits at the rim of the acetabulum?
Acetabular labrum
The femoral head is cartilaginous at birth + begins to ossify from the center outward at ___ months of age?
2-8
Differentiate abduct + adduct?
Abduct: move AWAY from midline
Adduct: move TOWARD midline
What 2 things create the acetabulum?
Triradiate cartilage (growth plate) + bone
What is hip effusion?
Increased fluid within joint
Can u/s differentiate b/w transient synovitis + septic arthritis?
No! Must aspirate the fluid to tell, as u/s can only assess for presence of fluid with hip effusion
What are the 2 main S/S of hip effusion?
Pain + limping or refusal to bear weight
___ is a common cause of hip pain b/w 3-8 years old?
Transient synovitis
Which type of hip effusion is self limiting/treated with anti-inflammatory meds + rest?
Transient synovitis
Both types of hip effuison have similar symptoms, which form m/c has milder symptoms + no long term effects?
Transient synovitis
Which type of hip effusion m/c presents with a fever?
Septic arthritis
Which type of hip effusion may have a recent history of a upper respiratory infection but are afebrile at presentation?
Transient synovitis
(afebrile = no fever)
___ is a serious bacterial infection + is considered a medical emergency that requires rapid treatment?
Septic arthritis
Which type of hip effusion may have elevated RBCs, C-reactive protein + WBCs?
Septic arthritis
Which form of hip effusion may present with complications if not treated?
Septic arthritis
Which form of hip effusion requires IV antibiotics + surgery if severe?
Septic arthritis
How do we align our probe when checking for hip effusion?
Place probe on the anterior part of leg + parallel to long axis of femoral neck
What measurements would indicate hip effusion on u/s?
Capsular thickness >5mm
OR
2mm difference b/w both hips (assuming unilateral)
What is developmental dysplasia of the hip (DDH)?
Range of hip dysplasia includinng instability, subluxation + frank dislocation
What is DDH also known as?
Congenital hip dysplasia (even tho most dislocations occur after birth)
List 2 causes of DDH?
-Mechanical (position in utero or after birth)
-Physiologic (maternal hormones in utero or physical makeup after birth)
Differentiate subluxation + dislocation?
Subluxation: partial dislocation
Dislocation: not in socket at all
What 2 maneuvers are used to assess hip stability?
Barlow + ortolani
The ___ maneuver attempts to push the femoral head posteriorly out of socket?
Barlow (a clunk is felt as the femoral head exits the acetabulum posteriorly)
The ___ maneuver attempts to reduce a recently dislocated hip?
Ortolani (a clunk is felt as the dislocated femoral head reduces into the acetabulum)
List 3 visual signs of DDH?
-Asymmetry of thighs or gluteal folds
-Discrepancy of leg lengths
-Positive allis or galeazzi sign
What is a positive allis or galeazzi sign?
Short femur when hips + knees are flexed (1 knee appears lower than other)
U/s of the hip is best performed up to ___ months of age?
6 (due to bony ossification, radiography is more reliable after)
During a hip u/s, do we only image the hip presenting with problems?
No, must image both to assess for asymmetry
___ angle is the m/c measurement obtained?
Alpha
The femoral head can be identified sitting in the ___?
Acetabulum
The iliac line should appear as a straight line superiorly or posteriorly?
Superiorly
The alpha + beta angles can be obtained by using the ___ scan plane?
Coronal
Where is the baseline, roof line + inclination line?
Baseline: along ilium through femoral head
Roof: along acetabular roof intersecting baseline
Inclination: across top of femoral head through labrum + intersects baseline + roof line
What is considered a normal alpha angle?
> 60 degrees
What info can we obtain when scanning coronally?
-Can assess the femoral head + see if it is in contact with acetabulum (50% normally sit in it)
-A dislocated hip will sit completely out of acetabulum
What is considered an abnormal alpha angle?
<60 degrees
90% of babies are born with which type of hip?
Type 2
Which scan plane is 90 degrees from coronal + is posterior lateral?
TRV plane
What shape is seen in TRV due to the ischium + femoral shaft wrapping around the femoral head?
U or V shape
What is the only plane we obtain measurements from?
Coronal
If a dislocation is seen in TRV, what should we do when scanning?
Apply stress (abduction) to observe reduction
___ is the gold standard for treating DDH?
Pavlik harness
Sonography of the hips should be done in what planes + what positions?
Scan both hips in coronal + TRV with neutral + flexed positions (supine or decub)
What 4 things create the hip joint?
Pelvic girdle, acetabulum, triradiate cartilage + femoral head
