Hip & Knee

Question 1

What is the femoral neck?

Answer 1

thin attachment of head to shaft
prone to fracture in elderly
Avascular necrosis of femoral head = blood supply cut off and bone dies

Question 2

What are the two angular relationships of the femoral neck?

Answer 2

Neck to shaft angle and angle of anteversion

Question 3

How many ligaments are in the hip joint?

Answer 3

4 extracapsular, 1 intracapsular

Question 4

What are the movements of the hip joint?

Answer 4

Question 5

How does loading of hip joint differ for genders?

Answer 5

Women have wider pelvis, different gait, and different neck to shaft angle

Question 6

what are the surgical options for hip disorders?

Answer 6

➢ Hip replacement (remove ball)
➢ Hip resurfacing (re-cap ball)

Question 7

Describe the two planes in which the knee joint moves?

Answer 7

Frontal plane: no motion when knee extended, motion incr as knee is flexed, max 30 degrees
Transverse plane: no motion when knee extended, motion incr as knee is flexed, max 90 deg

Question 8

What are the 2 joint of the knee?

Answer 8

Tibiofemoral joint
Patellatemoral joint
Sustains high forces and is situated between the bodies two largest lever arms - susceptible to injury

Question 9

Describe the instant centre technique

Answer 9

Joint motion in saggital and frontal planes
Description of the relative uniplanar motion of two adjacent segments of a body and the direction of displacement of the contact points.
Direction of displacement is tangential to the surface of the tibia, indicating the femur is gliding.
observed to displace from its normal position during some portion of the motion examined in knees with internal derangements.

Question 10

Describe the internal derangements of the knee joint

Answer 10

➢ Interfere with so-called screw home
mechanism, which is combination of knee
extension and external rotation of the tibia
➢ Clinical test (Helfet) test - determine
whether external rotation of joint take place
during knee extension, thereby indicating
that screw-home mechanism is intact

Question 11

Describe the loading of the knee joint in stance and swing phase

Answer 11

stance phase, force reaches peak value, load is sustained mainly by medial plateau ( greater surface area & cartilage thickness)
Swing phase, forces minimal sustained by lateral plateau

Question 12

What is the function of the meniscus?

Answer 12

joint reaction forces sutained. stresses increased following its removal
Protects cartilage and bone

Question 13

What is the function of the patella?

Answer 13

Aids knee extension by producing
anterior displacement of the quad
tendon during ROM, lengthening the lever arm of the quadriceps muscle force
Knee flexed patella is hidden behind condyles and provides 10% lever arm
at 45 degree patella provides 30%
patella removed quads produce 30% more force to rotate knee 45%.
Lever arm, protection, connection of tendons
M = F x d – increase d (Having that knee cap increases d allows you to reduce Fm to keep the same Moment)