Pelvis and Hip Biomechanics - part 2

what type of activity tends to have higher joint reaction forces

running and descending stairs

speed depends on

temporal and spatial parametes

walking gait pattern with aging

slower, shorter strides. Increase in hip and decrease in ankle ROM

running gait pattern with aging

increase adduction ROM indicative of abd weakness

what does walking speed increase

hip flexion and extension

antalgic gait pattern

abbreviated stance time and shortened step length

lateral trunk bending with gait

weak glute med or pain. Maybe trandelenburg

circuduction with gait

weak hip flexors. Momentum from extended position using glute med

backward trunk lean gait

weak glute max. Launching back at heel strike to interrupt forward motion of the trunk which compensates for weakness in hip extension. Commonly has difficulty with stairs

forward trunk lean gait

weak quad or hip / knee flexion contracture. Stabilizes by moving COG anterior to knee

excessive hip flexion gait

hip flexion contracture. Anterior pelvic tilt compensation

limited hip flexion gait

weak hip flexors which results in a shortened stride length. Commonly has issues with foot clearance.

limited hip extension gait

tight flexors or anterior capsule which results in a shortened stride length.

abnormal synergistic activity gait

excessive hip abduction and knee extension and ankle PF. scissoring or adducted gait pattern.

where does the COM shift with lateral trunk bending

laterally

what changes with lateral trunk bend shift

decreases lever arm which decreased torque and required abduction force

how does the force change if we take away an assistive gait device such as SPC

it decreases by almost half if not more

what population are hip fractures common in

geriatric

where do tension fractures occur

on the superior femoral neck

where do compressive fractures occur

on the inferior femoral neck

where is there a build up on a young femoral neck

the compression side

what happens with the aging femoral neck

there is cortical thinning and cancellous bone added in its place

compressive side injuries are most common due to

bony changes with aging and disease

tension side injuries are most common in those with

high level physical training, especially if they are poorly prepared or overweight. Fatigue of the abductor muscles plays a role

what muscle is protective against tension side stressors

abductors

what is common with femoral neck fractures or dislocations

avascular necrosis

what is a common injury in runners

femoral stress fractures

what type of fractures are more prone to catastrophic failure

tension side

if stress fractures are not addressed they can lead to

full frank fractures

what type of fractures account for almost half of all fractures of the proximal femur and occur in elderly individuals

intertrochanteric fractures usually resulting from a fall

with hip flexion contractures there is

increased metabolic costs and sub optimal articular cartilage loading

what is the therapeutic goal with hip flexion contractures

extension! stretch hip flexors, strengthen hip extensors, mobilize iliofemoral ligament, abdominal strengthening

stage 1 hip OA

minor loss of articular cartilage and minor bone spur growth. Mild occasional discomfort when joint is heavily stressed.

stage 2 hip OA

some bone hardening / sclerosis and occasional bone cyst, greater osteophyte formation with change in bone density, mild to moderate pain following intense activity, occasional joint stiffness

stage 3 hip OA

joint stiffness after prolonged resting, cartilage thinning and some joint narrowing, marked osteophyte formation

stage 4 hip OA

dramatically reduced joint space, bone end deformity with severe cartilage loss, frequent mild to moderate pain with occasional severe pain, joint stiffening and movement loss

what is slipped captial femoral epuphysis

a hip condition that occurs in teens and pre-teens who are still growing. Commonly in obese pts with endocrine disorders or children with down syndrome. it is when the femoral head slips away from the femoral neck.

what is legg-calve-perthes disease

necrosis of the femoral head due to resorption of bone

what can reossification result in with legg - calve - perthes disease

early degenerative joint disease

what age does legg-calve-perthes disease commonly occur in

4-10

bone overgrowth at head of femur is

CAM FAI

bone overgrowth at acetabulum is

pincher FAI

FAI is a

pain generator

changes in the spine can affect

the pelvis which can change other structures down the line

loss of lordosis can lead to

insufficent compensation of knee flexion to maintain balance