Exam 2: Hip Joint

Hip Joint Overview (type of joint, DoF, roles)

Triaxial ball and socket joint

• Concave acetabulum

• Convex femoral head

Degrees of Freedom (rotational)

• 3 DoF (flex/ext; ab/add; IR/ER) → Circumduction

Primary Role

• Support weight of head, arms, and trunk in closed chain

Secondary Role

• Position the foot in space during open chain activity

Acetabular Structure of Hip Joint

Acetabulum

• ilium, ischium, pubis

Acetabular Orientation

• opens Lateral, Anteversion (faces anterior slightly), faces Inferior

• There is more boney support in the back

Acetabulum parts

• Superior portion articulates with the femoral head

• Lunate surface (horseshoe shaped)

• Transverse acetabular ligament

  • supports blood vessels

• Acetabular fossa

  • Non-articulating w/ femur → empty space = vacuum seal for hip stability

Acetabular labrum (content, fxn, role for the hip joint)

• Fibrocartilagenous

• Deepens the acetabulum and creates a vacuum seal inside the joint

  • role: helps w/ stability

fxn:

Proprioceptive fxn

• Mechanoreceptors

  • aids in stability b/c stretch → gives message to CNS to reply w/ motor response

• Nociceptors

Dissipation of WB’ing forces

• deepens/increases Surface area → decreases stress

  • S = F/A
    

Acetabular depth

Depth: Center edge angle → Determines femoral head coverage

• Dysplasia

  • Low coverage → shallow acetabulum/socket → High mob + Low stability

• Coxa profunda

  • High coverage → too deep/overcovered → Low mob + High stab

Femur

Rounded head

• 2/3 sphere

Fovea (depression)

• Ligamentum teres attachment site

WBearing Adaptations

Femur neck: bending forces

• greater trochanter → head (upper neck): tensile forces

  • bad for neck b/c bone is NOT good at handling tension

• lesser trochanter → head (concave, lower neck): compressive forces

Adaptations:

• vertical line = resist compressive forces

  • parallel component such as

• horizontal line = resist horizontal forces

  • parallel component such as tendon, ligament, and glute med/abd resist

Someone w/ femoral neck stress fracture, which muscles to prioritize

prioritize hip abductor strength

Angle of Inclination

Def: Angle btw shaft & neck of femur

• Coxa valga = angle in medial side increased

  • vertical btw shaft & neck (180 dg)

• Coxa vara = angle in medial side reduced

Which name the angles of inclination?

Coxa Valga (Femoral Head Coverage (Area), MA of Glut Med, Force Needed from Glut Med, Joint Stress, Bending Moments)

Femoral Head Coverage (Area)=

• reduced → angle of inclination is high meaning less coverage
  

MA of Glut Med (to produce ABD)=

• reduced → b/c typ angle of inclination pushes greater trochanter more laterally to increase MA
  

Force Needed from Glut Med=

• increased → If no change in external forces, the internal force will need to be more to maintain equilibrium to compensate for small MA
  

Joint Stress=

• increased → FHC (Area) reduced and Force increased

  • S = F/A
    

Bending Moments (@ femoral neck)=

• decreased → femoral neck = more vertical meaning NO bending moments and would be more compressive forces

Coxa Vara (Femoral Head Coverage (Area), MA of Glut Med, Force Needed from Glut Med, Joint Stress, Bending Moments)

Femoral Head Coverage (Area)=

• increased → angle of inclination is small meaning more coverage
  

MA of Glut Med (to produce ABD)=

• increased → b/c greater trochanter is more lateral
  

Force Needed from Glut Med=

• decreased→ If no change in external forces, the internal force will need to be less to maintain equilibrium to compensate for large MA
  

Joint Stress=

• increased → FHC (Area) increased and Force reduced

  • S = F/A
    

Bending Moments (@ femoral neck)=

• increased → femoral neck = horizontal meaning bending moments can act

Angle of Torsion (Normal, Anteversion, Retroversion)

Normal:

• femoral condyles = horizontal & head of femur is NOT in same plane as condyles

Anteversion:

• both femur + acetabulum have anteversion

• Increased angle (off table + angle twd front)

Normal:

• head + neck in plane w/ femoral condules

• Reduced angle (twd table)

Femoral Anteversion (Femoral Head Coverage (Area), MA of Glut Med, Force Needed from Glut Med, Joint Stress, Bending Moments)

Femoral Head Coverage (Area)=

• reduced
  

MA of Glut Med (to produce ABD)=

• reduced

Force Needed from Glut Med=

• increased

Joint Stress=

• increased → FHC (Area) reduced and Force increased

  • S = F/A

Femoral Retroversion (Femoral Head Coverage (Area), MA of Glut Med, Force Needed from Glut Med, Joint Stress, Bending Moments)

Femoral Head Coverage (Area)=

• increased
  

MA of Glut Med (to produce ABD)=

• increasd

Force Needed from Glut Med=

• decreased

Joint Stress=

• increased → FHC (Area) increased and Force reduced

  • S = F/A

Angle of torsion

Supine uncompensated anteversion:

• hyaline cartilage (blue) more exposed anteriorly

• unstable in front of hip

Standing femoral medial rotation (toed-in):

• to get less of blue to be exposed

  • IR of femur → decrease anteversion + more covered acetabulum

  • patellas will face medially

Standing femoral medial rotation w/ compensatory lateral tibial torsion:

• overtime, there will be compensatory lat/ext torsion of tibia

  • allowing for feet to be pointed straight ahead

Is retroversion compensated?

No b/c hip is stable (more coverage of femoral head)

Joint Capsule

Very strong (stiff) - fibrous

• Large contributor to stability

Attaches proximal to the periphery of the acetabulum (stops @ trochanters)

Covers the head and neck distally

• Intracapsular: inside capsule (ex: labrum, synovial fluid)

• Extracapsular: outside capsule (ex: trochanter)

Thickened anterior/superior

3 reasons why Joint Capsule is thickened anteriorly

1) acetabulum = anteverted

• less bony coverage of fem head in front, meaning strong ligaments needed to support front

2) femur = typical anteverted

• more exposed femur than back of hip joint → less bone stability

3) Kinetics of hip joint

• line of gravity is posterior to axis of hip joint → wanting pelvis to rotate CW direction (post tilt/extension of hip)

• Ant ligaments give tension to have internal flexion forces

Capsular ligaments

• gives hip stability

• extension of hip

  • makes ant + post ligaments taut/tight under tensile load to limit hip extension

Accessory ligament

Ligamentum teres (head of femur)

• Fovea of femur acetabular notch

• some Source of stability

• some Source of secondary blood supply

Blood Supply

Medial and lateral circumflex arteries

• Deep femoral artery

• Supply hip capsule distally/anteriorly
  

Superior and inferior gluteal arteries

• Supply hip capsule proximally/posteriorly

Femoral head supplied by medial circumflex artery and vessels through the ligamentum teres

AVN

lack of blood supply to femoral head → decay of bone or become necrotic

Femur on Pelvis (Arthrokinematics)

Open chain: convex femur on concave acetabulum

• end of bone furthest from joint = trochanter

Abd → lateral superior roll and inferior medial glide

IR → Anterior roll, Posterior glide

ER → Posterior roll, Anterior glide

What is the influence of ROM of Femur on Pevis on ROM

Accessory glides:

• occurs closer to axis of joint needed for ROM

• without them → limited ROM

Muscles:

• end feel hypothesizes it, but there’s joint play or muscle length for accessing

For Measuring Hip extension ROM and Rectus Femoris Muscle length

Hip ext ROM:

• knee = extended

  • b/c NOT allow muscle length to limit amt of motion and reduce measurement → No passive insufficiency of RF

  • RF will be slacken (@ resting length w/ less tension)

Rectus Femoris Muscle length:

• hip = extended and prone

  • then flex knee to see length → stretching RF on both ends

For Measuring Hip flexion ROM and Hamstring flexion ROM

Hip flex ROM:

• knee = flexed & supine

  • b/c NOT allow hamstings length to be lengthened more than needed → No passive insufficiency of hamstrings

  • knee flexed → gives slack @ knee & you have slack to take up across hip

Hamstring flexion ROM:

• knee = extended & hip = flexed

  • to have passive insufficiency

Pelvis on Femur motion (ANT + POST pelvic tilt)

Anterior pelvic Tilt:

• ASIS moved anterior and inferior

• Movements of APT:

  • hip flexion → ANT part of femur gets close to ASIS

  • lumbar extension

Posterior pelvic Tilt:

• ASIS moved posterior and superior

• Movements of APT:

  • hip extension → ischial tuberosity gets closer to POST part of femur

  • lumbar flexion

Hip Drop (explain movement at pelvis, lumbar spine, contralateral hip joint)

Standing on left leg (Single left limb stance)

Movement pelvis:

• right pelvic/hip drop (b/cend furthest from axis of rotation drops)

Movement left hip joint:

• left hip joint ADDucts

  • brings midline to femur

Movement lumbar spine:

• left lateral lumbar flexion

Hip Hike (explain movement at pelvis, lumbar spine, hip joint)

Standing on left leg (Single left limb stance)

Movement pelvis:

• right pelvic/hip hike

Movement left hip joint:

• left hip joint ABDucts

Movement lumbar spine:

• left lateral lumbar extension

Forward/Backward Rotation

Right forward rotation:

• Stand on left leg

• Swing right side of pelvis forward

• Movement of lumbar spine: Right rotation

• Movement of left hip joint: Internal rotation

Right backward rotation:

• Stand on left leg

• Swing right side of pelvis backward

• Movement of lumbar spine: left rotation

• Movement of left hip joint: External rotation

Open vs Closed Chain

Open chain: pelvis muscles & trunk goes with it

Closed chain: pelvis moves but everything above pelvis is still

• Combo of Spinal flexion + Anterior pelvic tilt

• Pelvis anteriorly tilts but trunk goes with it

• trunk flexion

Open vs Closed Chain walking

Open chain walking:

• tight hip flexors → pelvis moves → anterior pelvic tilt

Closed chain walking:

• b/c of tight hip flexors → we can walk like B → what we look like

Hip flexors

• iliacus + psoas major (main hip flexors)

  • main hip flexors

• Rectus Femoris (2-joint muscles → gets actively insufficient)

• Sartorius

• TFL/ITB (offsets tensile loads on shaft)

Femur

• slightly bowed

• Lateral convex → tensile forces

• Medial concave → compressive forces

Hip adductor muscles

• Adductor brevis

• Adductor longus

• Pectineus

• Adductor magnus

• Gracilis

Hip Extensors

Gluteus Maximus (primary extensor)

• Max MA @ 0 dg (neutral hip) → Most mech advantage

• Peak torque @ 70 dg (hip flexion) → Most active tension + Peak force production

Hamstrings

• 2 joint muscle → torque based on position of knee

• knee flexed to 90 dg → try extend hip → hamstring becomes actively insufficient b/c it shortens @ both hip + knee

Gluteus Medius

• specifically Posterior fibers

Piriformis

Hip Abductors

• Gluteus Medius

• Gluteus Minimus

  • deep → closer to axis of rotation → less for mob but more for compression & stabilizing joint + femoral head

External Rotators

• Obturator Internus

• Obturator Externus

• Gemellus Superior

• Gemellus Inferior

• Quadratus Femoris

• Piriformis

Vectors = perpendicular to shaft of femur

• good @ ER & perpendicular to treatment plane (concave of acetabulum)

• makes good @ compression and stability

Internal Rotators

• Depends on position of hip

• Gluteus Medius (anterior fibers)

• Gluteus Minimus

• TFL

• Adductors

Posterior to blue dot (hip joint axis) = ER of hip

Anterior to blue dot (hip joint axis) = IR of hip

Active Insufficiency of Gluteus Max

fully shortened (knee flexed + hip extended) → Low force

peak → neither extreme

fully lengthened (hip + knee flexed) → Low force

Muscles pull on both attachment sites when they contract.

They move the end that’s easier to move —→ Crunches example

1) hip flexor muscles (iliopsoas + Rectus femoris) produces hip flexion via moving femur

2) after time, you get tired due to a lot of force needed to be made to move legs

• Anterior pelvis tilt occurs since its easier → back arches

3) Rectus Abdominus stops anterior pelvic tilt, so when you contract hip flexors they move femur

Active Insufficiency

2 choices for explaining diff in hip flexion:

Active Insufficiency with Rectus femoris

Passive Insufficiency with hamstrings

Postural Control ( if lean back or standing on something moving forward

COM will move back then BoS goes fwd

• this increased external moment of hip extension

• to maintain COM with in BoS, we need to create internal moment into hip flexion (which come from capsular ligaments or hip flexors)

• lean too back we need to move pelvis fwd to get COM fwd or take a step fwd to increase BoS

Hip strategies used for larger deviations of COM

Ankle strategies used for smaller deviations of COM

Postural Control (If lean fwd)

• gravity wants to flex hip so you need to use hip extensors

• COM goes too fwd, muscles can NOT handle it, so you have to take step back to be within BoS

Bilateral Stance

LoG falls posterior to axis of flex/ext of the hip

• Tend to rest in hip ext

• Need for muscle force:

  • Not in sagittal plane bc of capsule ligaments helping out

  • larger moments require muscle force

Equal external torques L and R

• Need for muscle force?": in frontal plane → moment on each hip joint

Unilateral Stance

Additive torques on the opposite side of the pelvis
▪ Gravity
▪ Contralateral limb

• pick up 1 leg → external force weight of head, arms, trunk & wight of leg picked up

• external moment is into left hip drop + right hip ADD

• Internal moment is ABD (gluteus medius)
  

Increased force from hip abd to maintain equilibrium

• MA of external moment larger than internal moment, meaning need a lot of gluteus medius to prevent pelvis drop due to internal moment being small

Joint reaction force
▪ 2-3x body weight

Strategies to Reduce Load

Having bag in left hand

• work harder working on left hand b/c increase external moment size

• right hand magnitude of force increases but external moment arm is brought closer to hip joint axis

• need less hip abductor forces

Cane = helps w/ BoS and balance out frontal plane moments

• pushing down on cane uses lateral trunk muscles that elevate pelvis

• if left side hurts, want cane to be in right hand

  • b/c if in left single limb stance, you have increased BoS and if you are contracting lateral trunk muscles that attach to your pelvis and can lift it. —> you want to lift right side

For someone withn osteoarthritis

• when having problem w/ right leg put bag on shoulder of Right leg

  • this allows for bringing mass closer to axis of rotation, requiring stronger (left) side to work more

FAI (Femeroacetabular Impingement)

Cam Impingement

• Femur side abnormality

• Labral tearing

• Articular cartilage degeneration

• Vulnerable in flex or
  abd

Pincer Impingement

• Acetabulum side

• Labral degeneration/calcification

Labral Pathology

• FAI

• Micro vs. Macro trauma

  • Posterior dislocation

• Stability role

  • Who picks up the slack if others aren’t
    doing their job

• Anatomical abnormalities

  • Over coverage/under coverage of
    femoral head

  • Coxa vara

Osteoarthritis

FAI

• Labral tears

• Instability

• No link between running and OA
  ▪ YAY!!!
  ▪ Need ideal amounts of activity for joint
  health

Fractures causes

• Trauma

• Osteoporosis/penia

• Gait speed???

  • Fast gait speed → land fwd → wrist fracture

  • Slow gait speed → land on buttock → hip fracture

• High mortality rate in the elderly