PT3 - Hip In Sitting Flashcards
What are the key functions of the spine and hip for sitting?
- muscular strength + control + ROM to transition from standing to sitting
- muscular endurance + coordination + control + ROM to maintain + adapt to sitting postures
What it’s the structure of the hip?
- deep ball and socket joint
- multi-axial (moves in combined planes) + combines movements e.g. flexion, extension, abduction, adduction, internal + external rotation, circumduction
- stable joint (ligaments + labrum + depth)
- labrum deepens socket + vacuum suction
- good for weight bearing => neck of femur angled
- thick hyaline cartilage on lunate surface
What are the specialisations of the femur and how can this lead to maladaptation?
- shape of femur relative to ground => valgus of knee making force disicipate through body
- superior surface well adapted for weight bearing, however, can end up maladaption due to changes in anterior/posterior/side bend/rotation
What are the articular specialisations of the hip?
- synovial ball and socket => lubrication, nutrition, waste removal, multi-axial
- femoral head + acetabulum => all motion between the 2 is rotational, no detectable translation due to congruency of articulating surfaces => smooth movement
- labrum + vacuum effect => provides congruency + deep socket for stability + provides absolute limits of motion + hydrostatic fluid pressure to facilitate synovial lubrication and resistance to joint distraction
What are the absolute limits of the hip before bony impingement occurs?
- flexion = 120 degrees
- extension = 10 degrees
- abduction = 45 degrees
- adduction = 25 degrees
- internal rotation = 15 degrees
- external rotation = 35 degrees
What is the function of the ligaments of the hip?
- strong => maintains articular congruity in all movements
- blend seamlessly with capsule of hip
What are the 3 main ligaments of the hip?
- iliofemoral = y shaped + blends with capsule + rectus femoris
- pubofemoral = rectangular + blends with capsule + obturator fascia
- ischiofemoral = spiral => maintains integrity during hip movement
What is femoroacetabular impingement syndrome?
- abdnormal contact between bone of proximal femur + acetabulum’s
- result of alteration in osteo us morphology of hip
- creates force on labrum => injury + pain + tearing => chondral injury + degenerative changes
- impingement = reduced area => between femur + acetabular rim
- thickening of labrum => inflammatory cascade
- impingement happens anteriorly, but can be felt into extension => inflammation + aggregated in multiple directions
- acute => can lead to chronic
What are the symptoms of FAI?
- hip pain
- clicking
- catching
- stiffness
- giving way
What are the signs of FAI?
- restricted ROM
- positive impingement test
What would you find in radiological findings?
- cam
- pincer
What are the tests for FAI?
- hip injections to confirm hip as source of pain
- FAI orthopedic test
- MRI/CT scan
What is a CAM morphology?
- boney growth on head of femur
- caused by off-centre rotation => non-spherical spinning => compression of labrum => more prominent in repetitive actions e.g. kicking
What is the morphology of a PINCER?
- development from child femur => pushed into acetabulum
- results in deeper socket
- change to ilium + pubis + ischium surface (deeper)
- can lead to OA
What interventions are available for PINCER/CAMs morphologies?
- surgical = bumpectomy or arthroscopy
What are the maladaptations of PINCER/CAMs?
- can lead to FAIS => accelerated changes => OA
- OA weight bearing may be painful
- OA neutral position may not be as stable
How might FAI present in a patient?
- sitting with leg externally rotated, abducted + dropping pelvis => flexed lumbar spine
- no weight bearing through hip in sitting => primary complaint of head + neck
- driving + getting out car + sit to stand difficult
- sit to stand => COG moves further forwards as needs to be with BOS
- leaning to side, rotate away to open up angle
- use arms of chair to stand up
- flex through thoracic spine without rotating pelvis (lumbar + thoracic + mechanical stress through areas load increase)
What are the muscular specialisations of the hip?
- diverse muscles cross hip joint
- bi-articular (muscles cross 2 joints) => transfer of tension in sit to stand between different points (slow down, speed up, lengthening + shortening)
- uni-articular (muscles cross 1 joint)
- diverse ROM architecture
NB - if PT is doing isolated based exercises => compound movement coordination difficulties
What are the bi-articular muscles of the hip?
- iliacus
- psoas major
- psoas minor
- semimembranosus
- bicep femoris
- semitendionsus
- sartorius
- gracillis
What are the uni-articular muscles of the hip?
- tensor fascia lata
- rectus femoris
- vastus lateralis
- vastus medialis
- piriformis
- gluteus maximus
- gluteus minimus
- gluteus medius
- pectineus
- adductor brevis
- adductor longus
- adductor magnus
What is a concentric action?
- loading + shortening of muscle
What is an eccentric action?
- lengthening under load
What is an isometric action?
- maintaining muscle length (Biarticular are best described as isometric)
How does stand to sit work using Biarticular muscles?
- hip flexors aren’t going to contract
- hip extensors => eccentrically contract to slow down movement (gravity always wins)
What is non-contractile soft tissue?
- tendons
- ligaments
- fascia
- other tissue between cells e.g. extracellular matrix
Explain sit to standing occurs
- gravity wins by leaning forwards
- creation of tension in non-contractile tissues
- storage of potential/elastic energy => take advantage of gravity
What is the function of muscles?
- maximum performance for minimum cost (energy efficiency)
- potential energy <- transferred to become -> kinetic energy
- using structures to mechanical advantage
What are the sit to stand kinematic?
- phase 1: flexion phase
- phase 2: extension phase
What happens during sit to stand kinematic?
- phase 1: flexion = first 35% of movement cycle
- phase 2: extension = begin at head and knee
- phase 2: reversal of head movement + rapid increase in knee extension
- phase 2: reversal movement spreads inferiorly from head => trunk => pelvis
- phase 2: reversal from flexion to extension => correspond with buttocks lifting off chair
What maladaptations might create challenges for someone to stand from sitting successfully?
- fixed flexion deformity => patient has flexion in hip and unable to get from flexion into extension
- FAI/OA => patient moves away from painful hip to push off non-FAI/OA leg (rotation through lumbar spine + pelvis + knee + ankle)
- posterior tilt of pelvis due to extended seated position => cannot get into flexion and uses trunk and head flexion to assist with movement
- uses hands to push off arms of chair as weakness in legs
How can frontal and transverse plan movements of the hip contribute to sit to stand efficiency?
- hip extensors generate force in frontal + transverse plane => may result in knees + feet coming inwards/outwards
- might rotate towards a specific direction
What influences the way we sit?
- enrivonment
- task
- organism
- centre = coordination + control
Discuss the potential effects of changes in hip mobility on the sitting posture of the pelvis and lumbar spine
- pelvis may be raised on affected side and anteriorly rotated to assist with flexion of the hip, contralateral side might be anteriorly rotated
- might observe muscle mass differences on each side where non-affected side has larger muscle definition due to more use for support; affected side might have atrophy of the muscles
What effect might FAI have on a person’s ability to sit and their sitting posture?
- FIA/OA => lumbar comes into a more side bent and rotated position to allow for less pressure onto the hip socket + leg more externally rotated + flexed + abducted on affected side
