The Hip

Question 1

Describe the 3 portions of the acetabulum.

Answer 1

Lunate surface = articulates with the femoral head and is covered with hyaline cartilage

Acetabular fossa = deepest portion of the acetabulum

Acetabular Notch = 60 -70 degrees wide opening in inferior acetabulum.

Question 2

What is the deepest portion of the acetabulum?

Answer 2

The acetabular fossa

Question 3

What surface of the acetabulum articulates with the femoral head and is covered in hyaline cartilage?

Answer 3

Lunate surface

Question 4

What is the wide opening in the inferior acetabulum?

Answer 4

Acetabular notch

Question 5

Describe the orientation of the neck of the femur.

Answer 5

Angulated so head faces medially, superiorly and anteriorly with respect to the femoral shaft and distal femoral condyles.

Question 6

What is the angle of inclination?

Answer 6

Angle between axis through femoral head/neck and longitudinal axis of the femoral shaft.

Typically 125 degrees

Question 7

What does coxa valga indicate?

Answer 7

A pathological increase in angle of inclination.

> 125 degrees

Question 8

What does coxa vara indicate?

Answer 8

A pathological decrease in angle of inclination.

<125 degrees

Question 9

What is the purpose of the angle of inclination?

Answer 9

Serves to optimize joint surface alignment.

Question 10

What can cause a slipped capital femoral epiphysis in adolescents?

Answer 10

A decrease in femoral neck shaft angle along with a high body mass index.

Question 11

What is the angle of torsion?

Answer 11

Angle between axis through femoral head/neck and the distal femoral condyles.

Normal = 8 - 20 degrees

Question 12

What allows for optimal alignment and joint congruency?

Answer 12

15 degrees of anteversion.

Question 13

Describe what is seen with excessive anteversion.

Answer 13

Increased angle of torsion.

• Reduces hip joint stability
• Associated with increased hip IR and decreased ER
• Commonly found with coxa valga

Question 14

Describe what is seen with retroversion.

Answer 14

Decreased angle of torsion.

• Associated with increased hip ER and decreased IR
• May cause impingement

Question 15

What may be associated with “in-toeing” gait in children?

Answer 15

Excessive anteversion

Question 16

What does the “in-toeing” aim to do?

Answer 16

Improve joint congruency.

But overtime may cause shortening of muscles and ligaments crossing hip and reduce ER.

Question 17

What is the positioning of the acetabulum?

Answer 17

Opening positioned laterally with inferior and anterior tilt.

Question 18

What determines the coverage of the femoral head?

Answer 18

The depth of acetabulum.

Question 19

What is acetabular dysplasia?

Answer 19

Abnormality where acetabulum is shallow.

Question 20

What is coxa profunda?

Answer 20

Abnormality of acetabular over-coverage. Excessively covers femoral head.

Question 21

What can excessive retroversion lead to?

Answer 21

over-coverage/impingement

Question 22

What can excessive anteversion lead to?

Answer 22

Instability

Question 23

Describe a Cam deformity.

Answer 23

When extra bone is present at anterior-superior region of femoral head and neck junction.
- As result there is loss of natural tapering of femoral head.

Question 24

What causes impingement in a Cam deformity?

Answer 24

Bulge of femoral head hits against the acetabulum.

*IR with FL maximizes impingement.

Question 25

Describe a Pincer deformity.

Answer 25

Abnormal bony extension of anterior-lateral rim of acetabulum. - Often associated with deep acetabulum or overly retroverted acetabulum. *FL and IR causes premature abutment of femur against acetabulum.

Question 26

What is the position for maximal congruency in non-weight bearing?

Answer 26

FL, ABduction, and slight ER *This position is utilized in diagnosis of hip dysplasia to improve joint congruency.

Question 27

Describe the bending moment of hip in regards to structural adaptation to weight bearing.

Answer 27

Half the weight of head, arms, and trunk passes down through pelvis and ground reaction force travels up the shaft. Creates: - superiorly: tensile forces - inferiorly: compressive force

Question 28

What does the trabecular systems provide?

Answer 28

Structural resistance. - Strongest where they cross at right angles - Zone of weakness is where they are thin and do not cross

Question 29

Describe the hip joint capsule.

Answer 29

Is a substantial contributor to hip joint stability. Composed of irregular, dense fibrous longitudinal and oblique fibers.

Question 30

Where is the capsule thickest and thinest?

Answer 30

Thickest anterosuperiorly Thin and loose posteroinferiorly

Question 31

Describe the function iliofemoral ligament (y-ligament).

Answer 31

Provides anterior stability to joint and controls IR and ER.

Question 32

Describe the function of the pubofemoral ligament.

Answer 32

Controls ER in extension.

Question 33

Describe the function of the ishiofemoral ligament.

Answer 33

Primary restraint to IR.

Question 34

What happens to all the ligaments with hyperextension?

Answer 34

All of them tighten.

Question 35

Describe the transverse acetabular ligament.

Answer 35

Protects the blood vessels that travel beneath it to get to the head of the femur.

Question 36

Describe the acetabular labrum.

Answer 36

Wedge shaped and deepens concavity. | - Acts as a seal to maintain negative intra-articular pressure.

Question 37

Describe the ligamentum teres.

Answer 37

Traditionally believed to serve only as a conduit for blood supply to the femoral head. - Excessive ER can strain/potentially tear

Question 38

What are the osteokinematics of the hip?

Answer 38

Flexion/extension AB/ADduction ER/IR

Question 39

What are the arthrokinematics of the hip during flexion?

Answer 39

Anterior roll and posterior glide

Question 40

What are the arthrokinematics of the hip during extension?

Answer 40

Posterior roll and anterior glide

Question 41

What are the arthrokinematics of the hip during abduction?

Answer 41

Superior roll and inferior glide

Question 42

What are the arthrokinematics of the hip during adduction?

Answer 42

Inferior roll and superior glide

Question 43

What are the arthrokinematics of the hip during IR?

Answer 43

Anterior roll and posterior glide

Question 44

What are the arthrokinematics of the hip during ER?

Answer 44

Posterior roll and anterior glide

Question 45

When weight bearing, where does the motion of the hip occur?

Answer 45

The femur is relatively fixed --> motion occurs by movement of pelvis on femur.

Question 46

What are the osteokinematics of the pelvis moving on the femur?

Answer 46

Anterior/Posterior pelvic tilt Lateral tilt Forward/Backward rotation

Question 47

What does an anterior and posterior tilt of the pelvis produce at the hip?

Answer 47

Anterior tiliting = produces hip FL Posterior tiliting = produces hip EX

Question 48

Describe the arthrokinematics (CKC) of an anterior and posterior pelvic tilt.

Answer 48

Anterior tilt = anterior roll, anterior glide Posterior tilt = posterior roll, posterior glide

Question 49

Describe the arthrokinematics (CKC) for lateral pelvic tilt.

Answer 49

Abduction = superior roll, superior glide Adduction = inferior roll, inferior glide

Question 50

Describe forward rotation of pelvis in CKC.

Answer 50

Side of pelvis opposite to stance leg moves anteriorly --> results in IR of the stance hip joint

Question 51

Describe backward rotation of the pelvis in CKC.

Answer 51

Side of pelvis opposite to stance leg moves posteriorly --> produces ER of the stance hip joint

Question 52

Describe the arthrokinematics (CKC) of IR and ER.

Answer 52

IR = anterior roll and anterior glide ER = posterior roll and posterior glide

Question 53

What is the closed pack position of the hip?

Answer 53

Full extension with slight IR and abduction

Question 54

What is the open pack position of the hip?

Answer 54

Moderate flexion, slight abduction, neutral rotation

Question 55

What is the capsular pattern of the hip?

Answer 55

IR = flexion = abduction