Hip region Flashcards
What is the angle of inclination for the hip?
- angle of the neck of the femur in the frontal plane
- normal = 125 degrees
What is coxa vera and coxa valga?
- Coxa vera: less than 125 degrees of AoI; distal segment toward midline
- Coxa valga: greater than 125 degrees of AoI; distal segment away from midline
What is the angle of torsion?
- rotation/twist between the femoral neck and shaft (femoral torsion)
- normal = 15 degrees of anteversion
What is anteversion of the hip?
- normal = 15 degrees
- excessive = greater than 15 degrees
What is considered retroversion of the hip?
- less than 15 degrees
What are some potential consequences of excessive femoral anteversion?
- dislocation risk
- joint incongruency
- increased joint contact stress
- wear on cartilage and labrum
Why does the “in-toeing” gait pattern occur?
- compensation for excessive anteversion by internally rotating the hip
- increases moment arm for hip abductors
- shortens ligaments & limits hip ER
Why is it a good thing that the thickest articular cartilage of the acetabulum is in the superior anterior region?
- this area has the highest joint forces while walking
- it increases contact area which reduces contact pressure
- keeps stress in physiological tolerable levels
What are the special qualities of the acetabular labrum?
- grips femoral head, deepens socket
- maintains interarticular pressure (suction-seal)
- keeps fluid from leaking out (synovial fluid) which is a fluid seal
- reduces friction
How does the hips close-packed position compare to the position of most articular congruence?
CPP: full ext. slight IR, & abduction -> most ligaments taut
MAC: 90 degrees flexed, moderate abduction, & ER
What is the normal position of the acetabulum?
inferior and anterior
- center edge angle (degree in which it covers femoral head) = 25-35 degrees
- acetabular anteversion angle (angle it faces anteriorly) = 20 degrees
What happens if there is a too low or too high center edge angle?
- Too low: reduced coverage = increased dislocation, sublux, instability
- Too high: increased coverage = impingement, injury
What happens if there is excessive or retroversion of the acetabular anteversion angle?
- excessive = reduces femoral head coverage
- retroversion = increases femoral head coverage
What are the arthrokinematics for femoral-on-pelvic flexion
femoral head spin
What are the arthrokinematics for femoral-on-pelvic extension
femoral head spin
What are the arthrokinematics for femoral-on-pelvic abduction
femoral head:
- rolls superior
- slides inferior
What are the arthrokinematics for femoral-on-pelvic adduction
femoral head:
- rolls inferior
- slides superior
What are the arthrokinematics for femoral-on-pelvic external rotation
femoral head:
- rolls posterior
- slides anterior
What are the arthrokinematics for femoral-on-pelvic internal rotation
femoral head:
- rolls anterior
- slides posterior
What are the arthrokinematics for pelvic-on-femoral flexion
acetabulum spins
What are the arthrokinematics for pelvic-on-femoral extension
acetabulum spins
What are the arthrokinematics for pelvic-on-femoral abduction
acetabulum rolls and slides superior
What are the arthrokinematics for pelvic-on-femoral adduction
acetabulum rolls and slides inferior
What are the arthrokinematics for pelvic-on-femoral external rotation
acetabulum rolls and slides posterior
What are the arthrokinematics for pelvic-on-femoral internal rotation
acetabulum rolls and slides anterior
Where does the AoR run for IR/ER?
- from femoral head to middle of knee joint
What ligaments are stretched with hip extension?
- iliofemoral
- anterior capsule
What ligaments are stretched with hip abd, ext, and ER?
- pubofemoral
What ligaments are stretched with hip IR and 10-20 degrees of abduction?
- ischiofemoral
How does ipsidirectional lumbopelvic rhythm differ from contradirectional lumbopelvic rhythm?
Ipsidirectional: spine and pelvis rotate in same direction
Contradirectional: spine and pelvis rotate in opposite directions
this allows the trunk above lumbar to remain stationary as pelvis rotates and is used during walking
Describe spinal movement for pelvic-on-femoral flexion
- anterior rotation of about 30 degrees pelvic tilt
- extension of lumbar spine
Describe spinal movement for pelvic-on-femoral extension
- posterior rotation of about 15 degrees pelvic tilt
- flexion of lumbar spine (reduce lordosis)
Describe spinal movement for pelvic-on-femoral abduction
- pelvis hikes on contralateral side (about 30 degrees)
- lumbar spine laterally flexes toward contralateral hike
EX: R hip abd = L hip iliac crest hiking and lateral flex of spine to the left
Describe spinal movement for pelvic-on-femoral adduction
- pelvis hikes on ipsilateral side (about 25 degrees)
- lumbar spine laterally flexes toward ipsilateral hike
What is “internal snapping hip syndrome”?
- iliopsoas abrasion from crossing inferior hip & femoral head
- usually during hip flexion
What are the hip flexors?
Primary:
- psoas major
- iliacus
- sartorius
- TFL
- rectus femoris
- pectineus
Secondary:
- adductor longus
- adductor brevis
- gracilis
- gluteus minimus
What are the hip adductors?
Primary:
- pectineus
- adductor longus
- gracilis
- adductor brevis
-adductor magnus
Secondary:
- bicep femoris (LH)
- glute max
- quadratus femoris
- obturator externus
What are the internal rotators of the hip?
- glute med & min
- TFL
- adductor longus/brevis
- pectineus
What are the hip extensors?
Primary:
- glute max
- bicep femoris (LH)
- semitendinosus
- semimembranosus
- adductor magnus
Secondary:
- glute med
What are the hip abductors?
Primary:
- glute med & min
- TFL
Secondary:
- piriformis
- sartorius
- rectus femoris
- glute max
What are the external rotators of the hip?
Primary:
- piriformis
- obturator internus
- superior gemellus
- inferior gemellus
- quadratus femoris
- glute max
Secondary:
- glute med & min
- obturator externus
- sartorius
- bicep femoris (LH)
What position is the worst torque potential for the abductors of the hip?
- 40 degrees abduction
- causes active insufficiency
What position is the best torque potential for the abductors of the hip?
- slightly adducted (elongated)
- occurs in stance phase of gait
Explain the force couple involved with anterior tilting of the pelvis
- sartorius depressed ASIS
- iliopsoas increases lumbar lordosis
- erector spinae elevates coxa
Explain the force couple involved with posterior tilting of the pelvis
- rectus abdominis elevates pubic symphysis
- glute max depresses posterior iliac crest
- hamstrings pull ischial tuberosity inferior
Explain how the adductors operate in the sagittal plane
- adductor magnus (post. fibers) extends the hip regardless of position
- @ 40-70 degrees of flexion other adductors lose torque potential
- outside of 40-70 degrees of flexion there is better leverage for flex/ext
What happens to the internal rotators (& some external rotators) when the hip is flexed to 90 degrees?
- torque potential increases from IR’s
- moves line of force from parallel to almost perpendicular
How is it that some of the adductors can internally rotate the hip?
- the femur has a natural bow to it
- although the adductors attach to the posterior aspect of the femur they are oriented in front of the AoR for IR/ER
- their line of pull creates an internal rotational force in anatomical neutral
Which muscle is most active in resisting a forward lean in standing and why?
Hamstrings:
- moment arm increases
- stretched across 2 joints which creates passive tension
- glute max held in neutral by nervous system for more powerful hip ext.
List the hip muscle groups in order from greatest torque potential to least
Sagittal: extensors > flexors
Frontal: adductors > abductors
Horizontal: IR’s > ER’s
Strongest to weakest
What are the impairments with a hip flexion contracture on standing posture with joints above and below the hip?
- very tight iliofemoral ligament and psoas major
- hip extensors shortened
- leads to degeneration where cartilage doesn’t overlap (all joints involved)
- joint compression increases
- leads to slight dorsiflexion, knee flexion, and increased lordosis
How can a patient with a spinal cord injury attain an upright posture without the use of hip extensors?
- they lean pelvis & trunk posteriorly which moves line of gravity posterior to the hips
- this creates hip extension torque
- stretches iliofemoral ligaments which creates a passive flexion torque
Explain the mechanisms of injury with a labral pathology
- rotation, repetitive, end-ROM movements
- hip dislocations
- strenuous lifting/pulling from full squat
- tears from compression, tension, shearing
- Idiopathic, trauma, excessive wear
What is Femoral-Acetabular impingement (FAI)?
- repeated contact b/w femur & acetabulum
- causes damage to labrum, sub-cartilage, and sub-chondral bone
What is a CAM lesion?
- femoral head overgrowth
What is a Pincer lesion?
- acetabular overgrowth
How is FAI related to OA?
- repeated outside-in trauma from bony impingement
- trauma to cartilage from altered arthrokinematics
- failure of damaged labrum to provide a fluid seal to joint
What is Developmental Dysplasia of the Hip (DDH)?
- abnormal growth/development resulting in a misshaped proximal femur
- starts at birth or 1st few years of life
- dislocation can occur frequently
- femoral head doesn’t sit in acetabulum
Describe the pathomechanics involved in greater trochanteric pain syndrome
- degeneration of distal tendon attachment of glute med and min
- could include bursitis (worsens w/ high, sustained, repetitive use of adductors
- tears, abrasions of tendons of glute med/min
In what way is greater trochanteric pain syndrome similar to rotator cuff syndrome of the shoulder?
- both usually show degeneration on the underside of the tendon
- pain usually insidious & chronic
- tendon compression
What is the difference between the trendelenburg sign and the compensated trendelenburg sign?
TS: hip drops on the contralateral hip
CTS: contralateral hip raises up, trunk leans toward ipsilateral standing leg
What is usually the cause of TS or CTS?
- hip abductor weakness
- strengthen hip abduction & Ext, IR, or ER
Explain how using a cane on the opposite side can reduce the joint reaction forces on the hip
- reduces abductor demand
- produces torque in same rotary direction as abductors
Explain how carrying a heavy load on the same side reduces joint reaction forces in the hip
- helps counteract the forces the abductors need to keep body weight upright
- helps abductors do their job with less work and JRF
What advice can we give our patients to reduce JRF at the hip?
- carry lighter loads
- use a cane on the contralateral side
- use bilateral carrying techniques
- carry heavier objects on ipsilateral side
- use a cane on contra side and carry on ipsilateral side
What are the positives and negatives of Coxa Varus Osteotomy?
Positives:
- increased moment arm for hip abductors
- alignment may improve joint stability
Negatives:
- increased bending moment arm increases bending moment torque = increases shear force across femoral head
- decreased functional length of hip abductors
What are the positives and negatives of Coxa Valgus Osteotomy?
Positives:
- decreased bending moment arm decreases bending moment torque = decreases shear force across femoral neck
- increased functional length of hip abductors
Negatives:
- decreased moment arm for hip abductors
- alignment may favor dislocation
What are some risk factors involved in hip fractures?
- age (70+)
- osteoporosis
- decreased bone density
- history of falling
- physical inactivity
What are some conditions that can lead to hip arthritis?
- FAI
- CAM/Pincer impingements
- labral tears
- inadequate joint forces
moderate PA helps w/ prevention
What are the post-op precautions for a posterior approach total hip replacement?
- no hip flexion past 90 degrees
- no hip adduction pasted midline
- no hip internal rotation
What are the AAOS norms for hip flexion and extension?
Flexion: 120
Extension: 20
What are the AAOS norms for hip abduction and adduction?
Abduction: 45
Adduction: 30
What are the AAOS norms for IR and ER?
IR: 45
ER: 45
