- Discussion:
- broad range of forces acts upon the
hip joint;
- muscles that cross hip joint generate most of the load that it bears;
-
femoral neck fracture:
- distance between the head and shaft of the femur determines the moment arm tending to produce varus;
- shorter moment arm, & thus less deforming force, follows valgus
reduction;
-
gait:
-
standing:
- wt of body equally distributed to lower limbs, so that weight on each femoral head is half of the body weight above hips;
- in one-legged stance, as in walking, head of femur serves as fulcrum;
- the standing hip must support the wt of the patient's head, upper extremities, torso, as well as
the contralateral, non supporting, limb;
- in order to maintain the pelvis level to the ground, the
gluteus medius &
minimus must
pull pelvis downward lateral to the fulcrum.
- upward opposing force is that of fulcrum, head of femur, force that is sum of the two downward forces;
- cane obviates decrease need for hip abductors on affected side to contract;
- may relieve upto 60% of the load on hip in stances phase;
- unsupported gait may result in 4 to 7 times body wt across hip where as supported gait (w/ a walker
or a cane) may produce loads across the hip of 2-3 times body wt;
-
supine:
- joint reaction forces during supine straight leg raising > 3 times body wt;
- getting on & off bed pan is equal to four times body wt;
Hip joint loading during walking and running, measured in two patients.
Telemeterized in vivo hip joint force data: a report on two patients after total hip surgery.
Telemetric Force Measurements across the Hip after Total Arthroplasty.
Medial-displacement intertrochanteric osteotomy in the treatment of osteoarthritis of the hip. A long-term follow-up study.
Hip Motion Measurements for Selected Activities of Daily Living.
R. Johnson MD. CORR Vol 72. Sept-Oct 1970.
The Effect of Cane Use on Hip Contact Force.
R.A. Brand. CORR Vol 147. March-Apr, 1980.
Mechanics of the normal and osteoarthritic hip: A new perspective.
R Bombelli and RF Santore.
CORR. Vol 182. 1984. p 69.
