PT3 - Hip In Sitting

Question 1

What are the key functions of the spine and hip for sitting?

Answer 1

• muscular strength + control + ROM to transition from standing to sitting
• muscular endurance + coordination + control + ROM to maintain + adapt to sitting postures

Question 2

What it’s the structure of the hip?

Answer 2

• 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

Question 3

What are the specialisations of the femur and how can this lead to maladaptation?

Answer 3

• 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

Question 4

What are the articular specialisations of the hip?

Answer 4

• 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

Question 5

What are the absolute limits of the hip before bony impingement occurs?

Answer 5

• flexion = 120 degrees
• extension = 10 degrees
• abduction = 45 degrees
• adduction = 25 degrees
• internal rotation = 15 degrees
• external rotation = 35 degrees

Question 6

What is the function of the ligaments of the hip?

Answer 6

• strong => maintains articular congruity in all movements
• blend seamlessly with capsule of hip

Question 7

What are the 3 main ligaments of the hip?

Answer 7

• iliofemoral = y shaped + blends with capsule + rectus femoris
• pubofemoral = rectangular + blends with capsule + obturator fascia
• ischiofemoral = spiral => maintains integrity during hip movement

Question 8

What is femoroacetabular impingement syndrome?

Answer 8

• 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

Question 9

What are the symptoms of FAI?

Answer 9

• hip pain
• clicking
• catching
• stiffness
• giving way

Question 10

What are the signs of FAI?

Answer 10

• restricted ROM
• positive impingement test

Question 11

What would you find in radiological findings?

Answer 11

• cam
• pincer

Question 12

What are the tests for FAI?

Answer 12

• hip injections to confirm hip as source of pain
• FAI orthopedic test
• MRI/CT scan

Question 13

What is a CAM morphology?

Answer 13

• 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

Question 14

What is the morphology of a PINCER?

Answer 14

• development from child femur => pushed into acetabulum
• results in deeper socket
• change to ilium + pubis + ischium surface (deeper)
• can lead to OA

Question 15

What interventions are available for PINCER/CAMs morphologies?

Answer 15

• surgical = bumpectomy or arthroscopy

Question 16

What are the maladaptations of PINCER/CAMs?

Answer 16

• can lead to FAIS => accelerated changes => OA
• OA weight bearing may be painful
• OA neutral position may not be as stable

Question 17

How might FAI present in a patient?

Answer 17

• 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)

Question 18

What are the muscular specialisations of the hip?

Answer 18

• 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

Question 19

What are the bi-articular muscles of the hip?

Answer 19

• iliacus
• psoas major
• psoas minor
• semimembranosus
• bicep femoris
• semitendionsus
• sartorius
• gracillis

Question 20

What are the uni-articular muscles of the hip?

Answer 20

• tensor fascia lata
• rectus femoris
• vastus lateralis
• vastus medialis
• piriformis
• gluteus maximus
• gluteus minimus
• gluteus medius
• pectineus
• adductor brevis
• adductor longus
• adductor magnus

Question 21

What is a concentric action?

Answer 21

• loading + shortening of muscle

Question 22

What is an eccentric action?

Answer 22

• lengthening under load

Question 23

What is an isometric action?

Answer 23

• maintaining muscle length (Biarticular are best described as isometric)

Question 24

How does stand to sit work using Biarticular muscles?

Answer 24

• hip flexors aren’t going to contract
• hip extensors => eccentrically contract to slow down movement (gravity always wins)

Question 25

What is non-contractile soft tissue?

Answer 25

- tendons - ligaments - fascia - other tissue between cells e.g. extracellular matrix

Question 26

Explain sit to standing occurs

Answer 26

- gravity wins by leaning forwards - creation of tension in non-contractile tissues - storage of potential/elastic energy => take advantage of gravity

Question 27

What is the function of muscles?

Answer 27

- maximum performance for minimum cost (energy efficiency) - potential energy <- transferred to become -> kinetic energy - using structures to mechanical advantage

Question 28

What are the sit to stand kinematic?

Answer 28

- phase 1: flexion phase - phase 2: extension phase

Question 29

What happens during sit to stand kinematic?

Answer 29

- 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

Question 30

What maladaptations might create challenges for someone to stand from sitting successfully?

Answer 30

- 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

Question 31

How can frontal and transverse plan movements of the hip contribute to sit to stand efficiency?

Answer 31

- hip extensors generate force in frontal + transverse plane => may result in knees + feet coming inwards/outwards - might rotate towards a specific direction

Question 32

What influences the way we sit?

Answer 32

- enrivonment - task - organism - centre = coordination + control

Question 33

Discuss the potential effects of changes in hip mobility on the sitting posture of the pelvis and lumbar spine

Answer 33

- 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

Question 34

What effect might FAI have on a person’s ability to sit and their sitting posture?

Answer 34

- 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