arthritis 11 Flashcards
(34 cards)
describe the role of exercise on bone growth when you are young *
long bone has 2 growth centres - 1 at each end
it is the Hueter-Volkman theory - increased compression at the growth plate slows down longitudinal growth, increasing tension at the growth plate speeds up longitudinal growth
describe the use of an 8 growth plate
if there is a fracture in growth plate it stops bone growing
put in 8 growth plate - compresses the bone so stops it growing so the other bone can catch up
describe different alignments/misalignments of the leg *
normal alignment - hip and ankle match up ie are in a straigh line - so the weight baring occurs evenly across the knee joint
varus - means go towards - all weight is on the medial side of the knee - bowed legs
valgus - all weight on lateral side of the knee - knocked knees
describe the effect of sport on alignment of legs *
sport = more bowed/varus legs
most people are slightly varus and sport squashes medial bone = less growth in medial bone = varus legs
by changing the shape of the bone you change the weight through the bone - this effects the mechanics
who gets valgus legs
models - have to like walk
women have wide pelvises mean angle of femer coming out of hip is altered
what is the effect of having valgus/varus legs *
have causes arthritis on the weight baring part - either get arthritis on outside or inside
there is no cartilige gap - it has been rubbed away
if present really late then the arthritis is disorganised because ligaments are involved
what are the effects of arthritis *
pain
loss of function
muscle weakness
loss of cartilage
osteophytes
should you do sport to prevent arthritis *
shoudl do a variety - not just 1 that will work a certain part of the bones because the bones will change shape to match
how can you treat valgus/varus legs
with osteotomy
cut bone - insert hinge to open/shut joint = change shape of leg - delays/prevents arthritis
can do 3D CT to see what would happen with the surgery
problem is identifying people early enough for this to work
describe Wolff’s law *
bone responds to the stress that you put on it
more load = more bone added
if stop using the bone it will dissolve away
problem in astraunauts - the trabeculae thin out
this happens at all ages
eg bone mass in tennis player’s dominant arm is stronger because muscles putting load on arm
describe developmental dysplasia of the hip *
effects babies
need the ball of the hip to be in the socket so that the bone grows around it - if the ball has slipped out you dont get this reaction = DDH
if never had hip in joint - the socket stays flat
risk factors:
- girls - because oestrogen makes ligaments more lax to allow childbirth = more likely for hip to slip out of place
- babies born breech
- right hip - that is the one that is pushed against the lumbosacral spine
- in utero life of the fetus - number of kicks
management of DDH (
need to put babies in harness so that the femer is kept in place - hold hip joint out so that via wolff’s law the hip will respond
depend on how carry baby - want legs flexed and abducted
problem with DDH *
increase the risk of arthritis because the bone is rubbed away quickly
what are the 3 groups of people that would get arthritis *
elderly - overwear
injury - torn structure around the hip eg labrum which leads to damage of the cartilage
young - around 40yrs - because of the shape of the hip based on actibity when young
summarise a standard hip joint *
spherical ball
slender neck
cartilage gap
describe a cam impingement *
due to a lot of exercise
femoral neck is under a lot of stress - therefore by Wolff law the bone deposits more to cope
therefore you get a lump of bone on side
caused by deep flexion
describe pincer impingement *
movement based - deep flexion
the socket is deeper
what is the problem with a cam impingement *
the bump knocks into the labrum everytime you deep flex eg when sitting/squatting
causes the labrum to tear
causes clicking and pain and the cartilage buckles up so quickly wears out = arthritis
describe the problem with pincer impingement *
causes labrum to tear
cartilage wear out on the opposite side to the pincer as well
describe treatment for cam impingement
surgery to scrape away the bump - stop it hitting the acetabulum
effective if early, but if already started affecting cartilage it is not
it allows you to preserve the joint
problem with joint replacement
only last for 20yrs - so if do them young you will have to have a lot of replacement
2nd replacement is less good because the bone left is weaker because it doesnt take as much yield because the metal cap takes all the yeild (wolff’s law) - so the bone dissolves
also becoming a pain reliever - people have it saying they will lose weight and exercise more afterwards but they dont
describe exercise and arthritis *
treatment for arthritis is exercise - keep load on bone so that they stay strong - wolff’s law
people avoid activity = weaker muscles = more weighht goiung through the joint that is normally taken by the muscles
therefore exercise is good for joint but should do a variety of exercise not extreme exercise in one area because 1 bone will take a lot of weight - need to do counter activities
cartilage also responds to load - so exercise increases cartilage
depends on how long and how consistant the cartilage is - not just the fact that you’re doing exercise
describe the structure of a synovial joint *
where 2 bones articulate
covered in fibrocatilage or hyaline cartilage
bathed in synovial fluid that is secreted by the synovial membrane
surrounded in articular capsule
describe menisci *
they are C shaped fibrocartilage
shock absorbers
deepen the socket and give stability
