Revision: frxs/dislocations of lower limb

Question 1

apophysis definition

Answer 1

bony projections lacking a secondary ossification site

Question 2

hip frxs

Answer 2

often applied inaccurately to fem head/neck/trochanters

avulsion frxs: cause: sports that require rapid de/acceleration eg sprinting, kicking a ball

result: a small pice of bone w/ part of tendon/ligament is avulsed
- occurs at apophyses and where muscles attach more often ie AS/IIS, ischial tuberosity, ischial pubic ramus

Question 3

dislocated epiphysis of femoral head

Answer 3

occur mostly in 10-17 year olds

cause: acute trauma/ repetitive microtraumas that place increased shearing stress on epiphysis

resulting in epiphysis slipping away from neck (due to a weakened epiphyseal plate) -> coxa vara

a symptom is hip discomfort that may be referred to the knee

a sign is a conformation from an x-ray

Question 4

coxa vara/valga

Answer 4

de/increased angle of inclination

Question 5

femoral frx types

Answer 5

distal femur

proximal

femoral neck

frx of greater trochanter or fem. shaft

Question 6

proximal femoral frxs

Answer 6

eg transcervical (mid. of neck), intertrochanteric

from indirect trauma

leads to an impacted frx -> foreshortening

Question 7

frx to neck of femur

Answer 7

most commonly occurs in elderly esp women (from OP)

• if it occurs in younger people, it is most often due to a traumatic injury (eg racing accident) when leg is extended leading to the force being transmitted up the foot to the femur
• if it occurs in children it can be from a traumatic hip dislocation/frxs that separate sup. fem. epiphysis

it is usually intracapsular

Result: -lat rotation of L/limb

• if the thigh is abducted then it can break the posterior acetabulum, also pelvic bone fragemnts can have the potential to cause serious damage to bladder, bowel etc
• disruption of blood supply to femoral head as the retinacular arteries may be torn
• > artery to head of femur still supplies blood but is often adequate for the whole head -> aseptic vascular necrosis
• in children: post tr. avasc. necrosis of head, retarded growth, hip pain that can radiate to knee
• if it is extracapsular, there will be no avascular necrosis

Question 8

frx to neck of femur cause

Answer 8

in older people: most common esp in women due to OP

in younger people: less common than in elderly, but can happen due to a traumatic accident eg race car accident where leg is extended and the force is transmitted from foor to femur

in children: due to traumatic hip dislocation/frxs that separate the sup. fem. epiph.

Question 9

frx to neck of femur result

Answer 9

lat. rotation of l/limb
(intracapsular) damage to retinacular arteries -> aseptic vasc. necrosis of fem. head (artery to head of femur can still supply, but it is often inadeq.)

If the thigh is abducted then it can break through the posterior acetabulum, also the pelvic bone fragments have the capacity to damage bowel, bladder etc

if it is extracapsular, there is no avascular necrosis as the medial femoral circumflex artery remains intact

in childen: post traumatic avasc. necrosis of head, hip pain that may radiate down to knee, retarded growth

Question 10

femoral frx of greater trochanter OR femoral shaft

Answer 10

from direct trauma, therefore more common in the active years of human life

can lead to spiral frx -> IMPACTION -> foreshortening

frx may be comminuted, and repair can take up to a year

Question 11

frx of distal femur

Answer 11

can be complicated by separation of condyles (-> misalignment of the articular surface of th knee joint), or haemorrhaging from popliteal artery

compromises blood supply to leg

Question 12

types of tibial frxs and general characteristics

Answer 12

shaft is narrowest between the middle and inf. thirds of the tibia - unfortunately this also has the worst blood supply of the bone - so frxs normally occur here

diagonal

-> boot top

compound

transverse stress

Question 13

compound tibial frxs

Answer 13

caused by direct trauma

frx may go through nutrietn canal

-> non union of fragments due to damage to nutrient artery

Question 14

tibial transverse stress frx

Answer 14

common in inexperienced people who suddenly begin to hike long distances, also from indirect violence when bone turns w/ foot eg in a football tackle

may frx ant. cortex of tibia

Question 15

diagonal frx of tibia

Answer 15

from severe torsion during skiing, esp from a high speed forward fall, when the leg angles over the rigid boot -> boot top frx

Impaction -> foreshortening occurs

Question 16

fibular frxs

Answer 16

commonly are 2-6cm proximal to the distal end of lat. malleolus and is often associated w/ frx-dislocations of ankle joint and frxs to tibia

can be caused by a person sliiping -> foot is excessively inverted -> ankle ligaments tear -> tilting talus towards malleolus and shearing it off

frx to med. and lat. malleoli can also occur

-> common in football and basketball, painful due to disrupted muscle attachments, walking is compromised due to the bone’s role in ankle stability

Question 17

dislocation of hip joint types

Answer 17

congenital

acquired: post/anterior

Question 18

congenital hip dislocations

Answer 18

fem. head is not properly inside the acetabulum and cannot abduct thigh

limb is shorter

Trendelenburg sign (hip drops when walking)

Question 19

Acquired hip dislocations

Answer 19

unusual as joint is very stable and strong

femoral head can take acetabular bone fragments and labrum w/ it

Question 20

posterior acquired hip dislocations

Answer 20

powerful force takes femoral head out

joint capsule ruptures inf. and post. -> head passes to lat. surface of ilium -> shortening and med. rotation

can lead to sciatic nerve injury -> paralysis of hamstrings and muscles distal to knee

Question 21

anterior acquired hip dislocations

Answer 21

violent injury -> hip is extended, abducted and lat. rotated

acetab. margins can frx -> frx-dislocation of hip

femoral head ends up inf. to acetabulum