biomechanics and pathology

Question 1

58. What are the internal forces acting on the hip?

Answer 1

a. active and passive forces arising from muscular and ligamentous pressures

Question 2

59. Describe the external forces acting on the hip?

Answer 2

a. ground reaction forces

Question 3

60. What type of forces must the hip manage with walking, stair, running?

Answer 3

a. walking- four times body weight

b. single leg stance 2.5x body weight

Question 4

61. What characteristic of the articular surfaces of the hip allow it to manage ground reaction forces?

Answer 4

a. the entire articular surface of the acetabulum is compressed when managing ground reaction forces
b. 70-80% of the femoral head is in contact with the acetabulum

Question 5

62. What part of the hip joint is most susceptible to OA?

Answer 5

a. the areas that bear the greatest weight which is primarily the anterior superior surface

Question 6

63. What is the femoral neck shaft angle?

Answer 6

a. angle between the femoral shaft and neck typically about 125 degrees

Question 7

64. How does body type effect femoral neck shaft angle?

Answer 7

a. tall slim people tend to have longer columns and greater column angles
b. short stocky people tend of have smaller column and smaller angles

Question 8

65. What is the femoral retrotorsion?

Answer 8

a. the head and neck of the femur position posteriorly to the transverse axis through the femoral condyles

Question 9

66. What is femoral anteversion angle?

Answer 9

a. the angle of the retrotorsion of the femur

b. measured by the difference in the transverse axis of the acetabulum and the long axis of the neck of the femur

Question 10

67. How does the anteversion angle change as we develop?

Answer 10

a. it decreases with age until full ossification

Question 11

68. What is the mechanical axis of the hip?

Answer 11

a. the line perindicular to the acetabular rim

Question 12

69. What is the transverse axis of the acetabulum?

Answer 12

a. line the runs in the transverse plane through the center of the femoral head

Question 13

70. What is the acetabular angle?

Answer 13

a. the angle between the mechanical axis and the transverse axis
b. 30-40 degrees anteriorly facing

Question 14

72. What is the open pack position of the hip?

Answer 14

a. 30 flexion
b. 30 adduction
c. 20 ER

Question 15

73. What is the closed pack positions of the hip?

Answer 15

a. maximum extension from zero
b. internal rotation
c. abduction

Question 16

74. Does RA effect men or women more?

Answer 16

a. women 3:1

Question 17

75. How do OA and RA compare

Answer 17

a. pathology
i. OA- reactive changes in the margins of the joint and subchondral bone
ii. RA- inflammatory process proliferation of synovial tissue and granulation of articular surface membrane
b. etiology
i. OA age, obesity, repetitive stress, genetics
ii. RA unknown, with possible genetic contributions
c. clinical manifestations
i. OA localized, slow onset of joint pain, stiffness (short duration)
ii. RA remission/exacerbation, long duration pain swelling fever, malaise, more common in women
d. common sites
i. OA- weight bearing joints
ii. RA- hands, wrist, knee, foot shoudler, hip, elbow, aankle, TMJ, SC, cervical spine
e. systemic manifestations
i. OA- none
ii. RA- pleuritis of heart and lungs, Sicca (dry mucous membranes)

Question 18

76. What is Coxa valga?

Answer 18

a. femoral neck shaft angle greater than 125 degrees

Question 19

77. How does coxa valga effect hip strength?

Answer 19

a. Decreases hip strength do to a smaller lever arm

Question 20

78. What is coxa vara?

Answer 20

a. femoral neck/shaft angle less than 115 degrees

Question 21

79. How does coxa vara impact the biomechanical chain?

Answer 21

a. decreased hip abduction due to early impact of the greater trochanter into the ilium

Question 22

80. What is femoral anteversion?

Answer 22

a. angle of retrotorsion greater than 20 degrees

Question 23

81. How does femoral anteversion impact the biomechanical chain?

Answer 23

a. toe-in gait
b. increased Q-angle
c. increased lordosis

Question 24

82. What is femoral retroversion?

Answer 24

a. angle of retrotorsion less than 12 degrees

Question 25

83. How does femoral retroversion impact the biomechanical chain?

Answer 25

a. femoral ER b. supinated foot c. decreased Q angle

Question 26

84. How many pathologies does the OGI ciriculum list as potential causes of hip AVN?

Answer 26

a. 31 with direct trauma and vascular impairments off various sorts toping the list

Question 27

86. What is Legg-Calve-Perth disease?

Answer 27

a. coxa plana or a flatening of the femoral head due to AVN

Question 28

85. Why is the hip susceptible to avascular necrosis?

Answer 28

nn

Question 29

87. What is the typical patient population for Legg-Calve- Perth disease

Answer 29

a. children 3-12 with boys > girls

Question 30

88. What is slipped capital femoral epiphysis?

Answer 30

a. During adolescence the femoral head slips inferiorly at the epiphyseal plate

Question 31

89. What is the typical patient population for slipped capital femoral epiphysis?

Answer 31

a. 10-15 years boys twice as more than girls

Question 32

90. How does congenital hip dislocations occur?

Answer 32

a. hormonal b. genetic laxity with shallow acetabulum c. breechdelivery d. envirnemental e. often anteverted

Question 33

91. Do men or women have priformis syndrome and hip dysplasia more?

Answer 33

a. Women 6:1 piriformis and 5:1 dysplasia

Question 34

92. What causes trochanteric bursitis?

Answer 34

a. repetitive adduction or leg length discrepancy with muscular imbalance b. increased Q-angle

Question 35

93. What are the bursa of the greater trochanter?

Answer 35

a. glut max and tendon of glut med (largest) b. glut med and greater trochanter c. glut minimus and greater trochanter

Question 36

94. What are the typical causes snapping hip syndrome?

Answer 36

a. thickening of the posterior border of the iliotibial band b. slipping of the psoas tendon over the iliopectinal eminence on the pubis c. osteochondromatosis, subluxation of hip or loose bodies

Question 37

95. Describe ishiogluteal bursitis?

Answer 37

a. found between iscial tuberosity and glut max | b. close to the sciatic nerve and posterior femoral cutaneous

Question 38

96. Describe iliopectineal bursitis

Answer 38

a. Similar to snapping hip because the bursa lies on the front of the hip separating the psoas tendon from the joint