Flashcards in Hip Deck (102)
T/F: The hip joint can move in all 3 planes.
true: horizontal, frontal, sagittal
What structure in the hip joint increases congruency and surface area?
T/F: The shape of the hip joint is well suited for stability.
What is the angle of inclination? What's a normal value for this angle?
- angle of inclination = how angled up the head of the femur is
- measured via line through shaft of femur and line through neck of femur
- normal = 125 deg
If the angle of inclination is less than 125 degrees, what is the term for this? What can this cause at the knee?
coxa vara, can cause genu valgus at the knee
What are the benefits and disadvantages from having an angle of inclination less than 125 degrees?
1) increased moment arm for abductors, improving force
2) alignment may improve joint stability
1) increased bending moment arm, which increases sheer force at femoral neck
2) shortens the fibers for glut med, completely negating the better moment arm
At what age is the angle of inclination permanent?
What does the angle of inclination impact?
fiber arrangement/length, moment arm, joint alignment and stability
With coxa valga, what is the angle of inclination?
greater than 125, more like 150
T/F: We start out with coxa valga at birth.
true, start at 150 deg and then it gets to 125
What are the negatives about having a coxa valga?
1) decreased moment arm for hip abductors
2) poor alignment favors dislocation
Increased sheer force on the femur neck occurs with what angle of inclination deformity?
Increased fiber length of abductors is a pro for what, coxa vara or coxa valga?
Decreased moment arm is a disadvantage for coxa vara or coxa valga?
In which deformity, coxa valga or vara, is the femur more likely to dislocate?
coxa valga, >125
What are the positives and negatives for coxa valga?
- positives = decreased sheer forces on neck, increased abductor fiber length
- negatives = easy dislocation, decreased moment arm for force of abductors
What are the positives and negatives for coxa vara?
- positives = increased stability, increased moment arm for abductor force
- negatives = shortened fiber length of abductors, more sheer force on neck
What is femoral torsion? How do you assess this, what position must the patient be in?
- how the femoral head and neck align with the condyles below
- patient must be prone
How is torsion measured? What's a normal torsion angle?
- Line through condyles and line through neck of femur
- normal torsion angle = 15 degrees anteversion (head twisted forward)
What is the normal angle of torsion for a baby? When does it resume the normal angle value?
~35 degrees, weight bearing decreases this angle till it's normal around 17/18 yo
What classifies a femur as retroverted?
What can excessive anteversion do to the adult? (3)
1) decrease abductor moment arm
2) destabilize joint
3) articular incongruence
How do we compensate for coxa vara/valga?
by going into genu valgus/varus at the knee, respectively
How do we compensate for retroversion? Anteversion?
retroversion = toe out to compensate
anteversion = toe in to compensate
What can accompany coxa vara?
coxa vara = genu valgus = anteversion = toeing in
Why is toeing in and out a bad compensation?
it may lead to more joint stability, but toeing out shortens the external rotators
- pt may complain of butt pain and present with limited internal rotation ROM
T/F: Excessive torsion can cause femoral anteversion.
What does the acetabular anteversion angle tell you? What's normal?
tells you how well the anterior acetabulum covers the anterior head of the femur; normal is 20 degrees
In what plane do you assess the acetabular anteversion angle?
in the horizontal plane