Hip Joint Flashcards
Percentage of innominate bones that make up acetabulum
Ilium and Ischium: 75%
Pubis: 25%
Which way is the femur’s convexity?
Anterior
- -> Compression force posteriorly
- -> Tensile force anteriorly
- -> Increased weight bearing tolerance
Femoral Head
Projects medially and slightly anteriorly
2/3 of a nearly perfect sphere
Femoral Neck
- Common site of fx
- Displaces the shaft of the femur away from the joint –> reduces chance of bony impingement
Intertrochanteric line
- Anterior
2. Attachment of ligaments
Intertrochanteric crest
- Posterior
2. Joins neck and shaft of femur
Acetabular labrum
Increases stability of hip joint - deepens socket
- Fibrocartilage
- Semi-circular
- Thicker medially, superiorly, posteriorly
- Helps reduce friction between bony surfaces
Femoral Neck Angle of Inclination
Angle between longitudinal axis of femoral neck to that of femoral shaft, in frontal plane
Newborn: 140-150
Adults: 125
Coxa Vara: 105
Coxa valga: 140
Femoral Torsion
Relative twist between proximal and distal femur
- Anteversion is normal
- Measure using Craig’s test
Abnormal torsion common with CP
Femoral Anteversion
Normal, > 6 years old: 12-15
Newborn: 30-40 degrees
Excessive anteversion –> Toeing in gait
- Pt will sit comfortable in “w” (hockey goalie) position
Femoral Retroversion
Less common than anteversion
–> toe out gait (in order to improve congruency of joint surfaces)
Congenital Hip Dysplasia
Can either be:
- Dysplastic
- Dislocated
Treatment: Pavlik harness (ABD, ER, Flex)
Legg-Calve Perthes Disease
Avascular necrosis of femoral head, resulting in flattened femoral head
- Boys 4-8 years old
- Insidious onset of intermittent anterior groin pain, may radiate to thigh and knee
- Antalgic gait
- Limited IR
- -> DJD
*Important to catch early
Treatment: Abduction orthosis
- Keeps femoral head in acetabulum, increasing blood flow
- May be worn up to 2 years
- Take off for short periods during day
Slipped Capital Femoral Epiphysis
Displacement of epiphyseal plate
- Males> Females
- Sudden onset, not necessarily associated with trauma
- Antalgic gait, leg ER
- Limited IR
- Pain can be felt in knee
Management: Stabilization
Often –> LLD
Acetabular Labrum Tears
- Not necessarily assoc. with trauma
- Young mean age: 38 years
Presentation: - Constant deep ache in groin with periodic sharp pain (can radiate to knee)
- Mechanical pain (locking, giving way)
- Frequently present in conjunction with OA
Greater chance of being missed in younger populations
No great special tests
Gold standard for diagnosis: MRArthrograph
Hip OA or DJD
- Often result of previous trauma or wear and tear
- Pain, stiffness, loss of ROM, limp, or need for assistive device
Treatment: Pain management, muscle balance exercises (strength), THA
- Often tight flexors and adductors, weak extensors and abductors
Imaging signs of hip OA
- Decreased joint space
- Osteophytes (often around rim of acetabulum)
- Sclerosis (whitening of bone)
How long does THA last?
15-20 years