disorders of the hip

Question 1

define osteoarthiritis

Answer 1

a clinical syndrome compromising joint paint accompanied by functional limitation and reduced quality of life.

Question 2

what are the risk factors for primary osteoarthritis

Answer 2

age
female
ethnicity- increased risk in African-American, American Indian or Hispanic women
genetics
nutrition- diet rich in vit Cand E may provide some protection against OA

Question 3

state some causes of secondary OA

Answer 3

obesity
trauma
malalignment e.g developmental dysplasia of the hip
infection e.g septic arthritis,tb
inflammatory arthritis- rheumatoid arthritis, ankylosing spondylitis
metabolic disorders affecting the joints e.g gout
haematological disorders e.g haemophilia with bleeding into joints
endocrine abnormalities e.g diabetes mellitus with neuromuscular impairment

Question 4

describe the pathology of OA

Answer 4

precipitating risk factors lead to excessive loading of joint and damage to hyaline cartilage covering articular surface
the hyaline cartilage becomes swollen due to increased proteoglycan production by chondrocytes. this stage is the attempt to repair the cartilage.
the articular cartilage is replaced by fibrocartilage which is rough.
flaking and fibrillation develops along the normal smooth cartilage. over time cartilage becomes eroded down to subchondral bone resulting in loss of joint space.

Question 5

symptoms of osteoarthritis of the hip

Answer 5

joint stiffness when getting out of bed or sitting fir a long time
main, swelling or tenderness in the hip joint.
crepitus: sound or feeling of bone rubbing against bone (crunching)
reduced ability to move hip to perform routine activities

Question 6

what do the surface changes in the cartilage cause

Answer 6

eburnation- subchondral bone responds with vascular invasion and increased cellularity becoming thickened and denser. eburnation manifests as subchondral sclerosis on x-rays
subchondral bone cysts - due to cystic degeneration
osteophytes- due to osseous metaplasia of connective tissue.

Question 7

what is a positive result from the trendelenburg test

Answer 7

when standing on one leg the hip goes up on the affected side as the abductor muscles are weak.
trendelenburg gait

Question 8

what are the four cardinal signs of OA on an X ray

Answer 8

reduced joint space
subchondral sclerosis
bone cysts
osteophytes

Question 9

how is OA managed (non-operative)

Answer 9

activity modification
weight loss
stick/walker
physiotherapy
medications : NSAID(ibuprofen, naproxen), COX-2 inhibitors, nutritional supplements
injections: corticosteroids and viscosupplementation

Question 10

how can OA be managed (surgery)

Answer 10

hip replacement surgery

reduces pain and improves patient well being

Question 11

what is the fracture of the femoral neck defined as

Answer 11

a fracture of the proximal femur , up to 5cm below the lesser trochanter

Question 12

what are the different classifications of fractures of the femoral neck

Answer 12

intracapsular

extracapsular- further divided into intertrochanteric and subtrochanteric

Question 13

what is a intracapsular fracture of the femoral neck

and when does it occur

Answer 13

disrupts the ascending cervical branches of the medial femoral circumflex artery
due to the inability of the artery of the ligamentum teres to sustain metabolic demand of the femoral head there is a high risk of avascular necrosis of the bone
occur after a minor fall
in elderly especially post menopausal women with osteoporotic bone

Question 14

how does an extracapsular fracture affect blood supply to femoral head and when do they occur

Answer 14

the retinacular arterial supply to the femoral head is likely to remain intact
affect young children and middle aged people.
usually the result of significant traumatic force (road traffic accident)

Question 15

how are fractures of the femoral neck treated

Answer 15

hemiarthroplasty-surgical replacement if femoral head only

total hip replacement- replacement of head and acetabular cup

Question 16

what are the symptoms of a fracture in the femoral neck

Answer 16

reduced mobility/ sudden inability to bear weight on the limb
pain which may be felt in the hip, joint and/or knee

Question 17

why is the hip shortened, abducted and externally rotated in a displaced fracture of the femoral neck

Answer 17

shaft of femur moves independently of hip joint
shortening of limb as muscles of the thigh (rectus femurs, adductor Magnus and hamstring) pull the distal fragment of the femur upwards
abducted due to strong abductors that attach to greater trochanter (gluteus medius and minimus)
externally rotated due to iliopsoas and short lateral rotators (piriformis, obturator internus, superior and inferior gemelli and quadratus femoris)

Question 18

what can cause avascular necrosis (temporary or permanent loss of blood supply to the bone)

Answer 18

mechanical disruption (broken hip)
alcoholism 
excessive steroid use 
post-trauma (injury)
thrombosis 
hypertension

Question 19

what is dislocation of the hip defined as

Answer 19

head of femur being fully displaced out of the acetabulum of the pelvis

Question 20

what is presented in physical examination of posterior hip dislocation

Answer 20

shortened limb
internally rotated
adducted
flexed

Question 21

what is presented in physical examination of anterior hip dislocation

Answer 21

externally rotated
abducted
slightly flexed

Question 22

what is presented in physical examination of central hip dislocation

Answer 22

always a fracture dislocation
femoral head palpable per rectum
intrapelvic haemorrhage

Question 23

what are the complications of hip dislocations

Answer 23

avascular necrosis 
post traumatic OA 
recurrent dislocation 
sciatic nerve injury /foot drop 
infection