Biomechanics/Intro Name what is going on by theName what is going on by the

Name what is going on by the

distal segment on the proximal segment

Big four

squat, lunge, plank, single limb stance

Hip ADD/ABD OKC

Relationship of the distal segment relative to the midline of the proximal segment

Frontal plane motion around sagittal axis

hip rotation

IR/ER

Hip ADD/AB CKC

Add= CL pelvic drop

Weak glute med

Ab= Cl pelvic rise

QL activity

Tib ab/ad

Ab= valgus

Ad= varus

Lean towards stance limb

if you have a weak glute med also decrease compressive forces

Hit and go inward at the knees = unloading the knee-pain response

With OA the compensations will not exactly line up with the pain

Acetabulum positioned

Positioned laterally with inferior and anterior tilt

Provides over coverage

Periphery is covered by

hyaline cartilage

Hyaline cartilage is strong- smooth

In acetabulum and the femur

deepened by

fibrocartilaginous labrum

Also supported by ligaments and capsule too

Orientation- frontal plane

Center edge angle / center edge angle of Wilberg

Center edge angle / center edge angle of Wilberg

Amount of acetabulum that covers the femur

Highly variable

Average 35 deg in adults

inc/dec wiberg

Inc angle = less mobility, joint loading

Dec angle= less and unstable coverage

Over coverage - hip impingement

Under coverage - hip instability or hip dysplasia

Orientation- horizontal transverse plane

Acetabular anteversion angle

Acetabular anteversion angle

Orientation of the acetabulum within the horizontal plane in relation to the pelvis

Extent which acetabulum projects anteriorly in horizontal plane

Average 20 deg

Males 18.5

Females- 21.5

inc dec Acetabular anteversion angle

Increased angle = less coverage of the femoral head

Inc ER, Dec coverage, Dec stability

Dec ante-version angle= inc coverage and inc stability

Aka could be retroverted

Femur- Fovea capitus by way of ligamentum teres supplies blood

But this is only in childhood

As we age its taken over my medial and lateral circumflex arteries which are branches off femoral artery

femur characteristics

Largest and strongest bone in the body

Head of femur is covered by hyaline cartilage (2/3)

hip capsule

Irregular dense fibrous structure

Attached to periphery of acetabulum to base of femoral neck

Thickened anterior superiorly

Supported by ligaments

Hip labrum

Deepens socket and increase concavity of acetabulum

Maintain negative intraarticular pressure

Nerve endings provide proprioceptive as well as nociceptive feedback

Very innervated decent blood flow

Free nerve endings and nociceptive so can produce pain

Tears can decrease the stability of the joint

illiofemoral

Y= supports hip anterior

Resist extension, IR, and some ER

pubofemoral

resist abduction, ER

Loose during flexion - can be taut on extension

ischiofemoral

Resist extension

Ankle of inclination

Kids have higher angles

125 is normal angle of inclination

What causes the shift- starting to load the limb- gravity pull of muscles ect.

coxa vara

Inc moment arm for hip abducotrs

Alignment may improve joint stability

more bending force higher risk of fractures , inc shear force on femoral neck

Dec functional length of hip abductors

This is more stable compared to valga

Angle less then 105

coxa valga

Lots of point contact in a smaller area

Dec bending moment arm- Dec benign movement - Dec hear force on femoral neck

Angle over 140

Alignment may favor dislocation

Adductor moment worse - abductors shorter length and may not have to work as hard

Abductors dec moment arm

Dec shear force - less fractures

Alignment may favor dislocations

Inc functional length of hip abductor muscles

closed packed hip

max hip extension, medial IR, abduction

Max congruency is actually frog like butterfly position

Reason doesn't follow is the angle of the acetabulum

capsular pattern

IR>Ext>Abd>flex>ER

Ext is first thing a pt notices

Congenital hip dysplasia

Abnormal contact of the hip in utero

More shallow acetabulum

Lower center angle on imaging

Developmental dysplasia of the hip - DDH

No known etiology

Familial link

Bilateral - can be unilateral but may not get picked up until child starts to walk

Usually first born children

More prevalent in females

breech

More creases on limbs- one leg lower then the other

Different leg lengths

Ligaments that maintain head are lax

Femoral head can sublux or dislocate

1-2 cases per 1000 births

Physicians screen for this after birth

degrees for possible dysplastic

16 deg or less of Wiberg angle is dysplastic

16-25 is possible dysplastic

How's it diagnosed

Asymmetry limb and skin folds

Infant = ortolanis sign / Barlow test

Diagnosed in older children - walking is usually delayed, once walking abnormal gait (limp, waddling)

barlow

flex femur and push down while adducting

Sublux

ortolani

opposite and then this reduces it

Treatment birth to 6 months

Dislocation reduced and the hip then maintained in a Flexion, abduction , ER (frog leg), with harness or spica casted

90% success if discovered within 6 weeks of birth

treatment up to 3

will attempt conservative treatment, will attempt to utilize traction and progression of abduction to try and reshape acetabulum

Often times will result in a closed reduction

4-8 years old

Reduction done surgically

Periacetabular osteotomy

Breaking femur and pelvis and rotating them to allow more coverage of the joint

Very significant procedure - 6 month rehab

Showing promising result if done earlier - before they are skeletally mature

Good to get back ADLs not really to be athlet

Don't exactly know the long-term effects

The short term outcomes are promising

Slipped capital femoral epiphysis (SCFE)

Older child

Early adolescents with rapid growth

Female= 10-13 y/o

Male= 12-16 y/o

2-10/100,000 adolescents

risks scfe

Males higher risk - 60-65%

Obesity

Coxa vara due to high shear forces

Head slips off posterior

Grade it by how much is posterior or how much has slipped off

S&S Scfe

poorly localized pain over the thigh, groin, knee (often medial knee pain may by only symptom)

Intermittent limb

LE goes into ER in supine and with hip flexion

Ortho red flags is that excessive ER

Gradual onset

Pain and stiffness over time

Referred pain into the knee - aka medial knee pain

Could have some gluteal pain

No MOI- based over time - body habits and inclination angle can push femoral head

consequences scfe

growth plate wont heal, avascular necrosis (impacts the medial and lateral circumflex arteries)

treatment scfe

percutaneous pinning- screw going through neck into the head - does not rotate not it all can move as one thing liek its supposed to

Early diagnosis allows greater chance for successful stabilization

Femoral torsion

Twist between the neck of the femur and the shaft

Estimated in infants to be 30-40 deg

Angel decreases 1.5 deg per year

Normal - 10 to 20 deg

Male=15

Female=18

Femoral anteversion -

angles greater than 15-20

Inc IR greater then ER they have more space to do that

If they IR they can compensate and line the dots up- compensation only occurs at eh hip

If you toe in- you can compensate at the hip but its not compensated at the tibia

Femoral retroversion

angles are less then 15-20

Just less in the anterior direction

Femoral torsion test

craig test

Males = 8-12 deg

Females= 12-18 deg

Q angle

Males= 12, females=15

Angle of the pull of the quad

ASIS to center patella to the tibial tuberosity

Why patellar femoral pain syndrome is more in females then males

Compensation at hip with IR and tibia stays same - more of the increases the q angle

Results excess anteversion

Internally rotated toeing in gait- pigeon toed

Tibial ER to get toes straight

Foot might be a little more pronated

Medial long arch job to be stable and is a mobile adapter and will follow the IR and pronate more

Appearance of genu valgus

Increased lumbar lordosis- due to the inc anterior tilt of the pelvis

Causes inc anteversion

W sitting position

Weight of body turning into that position

Toe in= inc anteversion

toe out

Toe out= dec anteversion or retroversion

The hip is always going to be compensated, uncompensated usually talking about femur and tibia

Results of excess retroversion

If they don't compensate of the tibia= bow legged appearance more valgus

Tibial torsions

Twist in tibial bones themselves

Leg calve perthes disease (LCP)

Flattening of the femoral head

Positioning but also damage to blood flow

Idiopathic

Ages 4-10

Very active

Small for age

Osteonecrosis of the femoral head

Leads to flattening of the femoral head

Usually unilateral: 10-12% bilateral

1 in 12,000 children

LCP causes

trauma, inflammation of the capsule or synovitis, dec blood flow

LCP symptoms

limping slight dragging of leg

Limited hip Abd and IR

Due to adductor spasms

Feel very tonic compared to the uneffected side

Pain in groin, thigh, medial knee

Treatment LCP

Prevent lasting deformity of the femoral head and keeping the femoral head in the acetabulum

Restrict activities

ROM and strengthening exercises

Dec WB- crutches/walker

Usually, WBAT

Early diagnosis = femoral head has potential to remodel if caught early enough