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
Most common THA approach:
Posterolateral
Lateral approach: Detach glut med, more limp afterward
Anterior approach: B/w TFL and IT band
Femoral Fracture
- 20% die within a year, related to fx
- 80% over 65 are female
- Risk doubles each decade after 50 (osteoporosis + fall risk)
Femoral neck fracture sign
Injured limb is externally rotated with a shorten limb length on that side
Hip Joint Capsule
Attachments: Intertrochanteric line and lateral 1/3 of posterior neck
- Very strong and thick
- Forms a cylindrical sleeve
- Encloses neck
- -> Can hold everything together if there is a femoral neck fx without displacement
Open/ close pack position of hip
Open: Flex, ABD, ER
Closed: Ext, ABD, IR
Most congruent: 90 flex, mid range ABD and ER
Hip joint ligaments
Iliofemoral
Pubfemoral
Ischiofemoral
All 3 wind around femoral head
Limit extension as a whole
Allow for flexion
Iliofemoral ligament
- AIIS to intertrochanteric line
- Anterior lateral capsule
- Strongest
- AKA Y ligament
- Limits extension and ER
- Passive role in stance
Pubofemoral ligament
- Medial inferior capsule surface
- From superior ramus of pubic to neck of femur
- Limits extension and abduction
Ischiofemoral ligament
- Posterior capsule
- Posterior acetabulum to femoral neck
- Limits extension and IR
Ligamentum Teres
Small intracapsular ligament (from acetabulum to fovea of femur)
Key component to femoral head integrity
- Arterial supply and innervation
- Checks lat and sup subluxation
- Possesses mechanoreceptors
Bursas in hip
Ilipectineal, trochanteric (multiple), ischial
Blood supply to hip joint
Branches of medial and lateral circumflex arteries
Ligamentum teres
Nerve supply to hip joint
Branches from obturator and gluteal nn.
Nerve to quadratus femoris
Representation L2-S1
Normal ROM for hip motions
Flexion: 120 Extension: 20 - more likely to lose than flex Adduction: 25 Abduction: 45 IR: 35 ER: 45
Which types of muscles tend to get tight?
Two-Joint muscles
Iliopsoas attachments
Iliac fossa, Anterior T12-L5 –> Lesser trochanter
Action:
- Hip flexion
- Ant pelvic tilt
- Lumbar extension
Adductor group attachments
Inferior pubic rami –> Adductor tubercle
Control hip and pelvic motion during WB
Gluteus Maximus
- Large, single joint, quadrilateral shaped, thick, superficial
- Posterior sacrum and ilium –> Posterior femur (distal to greater trochanter)
- Fibers attach to IT band and thoracolumbar fascia
- Weak glut max often compensate with hamstring
Glut Med
- Ilium to greater trochanter
- Critical in unilateral stance (control and stabilize pelvis)
- OKC hip abduction (ext and ER)
- CKC stabilize neutral pelvis
“Money muscle” of hip
TFL
- External lip of iliac crest –> IT tract –> Lateral tibial condyle
- Flex, IR, ABD (pelvic stabilizer)
Often recruited when pt has weak glut med
Piriformis syndrome
- Compression of sciatic nerve due to shortening and/or hypertonicity of piriformis
- Radicular pain
- Frequently associated with decrease in function of pelvic stabilizers
- Sacral torsion can be present
Biomechanics of walking : Sagittal plane
- Hip flex/ext: Often lacking ext, may flex knee early to compensate, or affect trunk position (look at arm swing)
- Lumbar and knee actions
Biomechanics of walking: Frontal plane
- Hip abd/ add
Greatest deviation noted in single limb support
Look to see pelvic obliquity change
Trendelenburg gait
Biomechanics of walking: Transverse plane
- IR/ER
Initial contact: ER of femur
Loading phase: progression into IR (eccentric ERors)
Terminal stance: Motion back toward ER
Problem: Fails to move into IR or moves into ER too quickly
PROM exam for OA:
- Ext often restricted
- Capsular pattern of limitation has been proposed (IR, flex, ABD, ext) - and refuted.
Why do a lateral glide of hip?
Tight Adductors
Why use direct hip traction vs. pulling at ankle?
Knee pathology
