Arthritis Flashcards
what effect does exercise have on arthritis?
- arthritis is not worsened by sports, but improved
- exercise just increases the risks of breaks that contribute to arthritis
what does the Hueter-Volkmann’s Law describe?
increased compression at the growth plate slows down longitudinal growth,
increasing tension at the growth plate speeds up longitudinal growth (stretching a yute)
what sort of (mis)alignment/deformity is seen in sports players?
varus alignment (outward bowing)
what sort of (mis)alignment/deformity is seen in models/slim women?
valgus alignment
inwards
what sort of alignment is seen in those with sedentary jobs?
neutral alignment
what is the risk associated with varus knees?
higher risk of osteoarthritis
where is the load placed on, leading to the varus deformity?
abnormal pressure on the medial knee joint
[push knees outwards from the inside]
where is the load placed on leading to the valgus deformity?
abnormal pressure on the lateral knee joint
[push knees inwards from the outside]
what change occurs in arthritis? when can it be diagnosed?
the cartilage gap decreased
diagnosed when Pt presents with pain rather than a biochemical test
what effect does sport have on the intercondylar-intermalleolar distance?
it increases the distance –> varus alignment
what is done surgically to realign varus/valgus alignment?
Osteotomy
- correct a mis-alignment in a younger person and thus can reduce incidence of arthritis later in life
- a bone is cut to shorten or lengthen it or to change its alignment.
what does Wolff’s Law describe?
bones respond to stresses that are put on it
Higher stresses than normal will lead to more bone been laid to support itself
give example of situations where Wolff’s Law applies
o Surfers knobs/knuckles
– kneeling on board can lead to bone growth.
o Dis-use atrophy in astronauts.
o Tennis players get dominant forearm appositional bone growth.
what is Developmental Dysplasia of the Hip (DDH)?
In-utero malformation of the hip socket where the femoral head is not in location for the socket to form around it (the femur head being there should stimulate development of the socket)
This means the femur head is dislocated –> abnormal hip joint in the newborn
they are more likely to develop osteoarthritis when they are older
what are the anatomical features of a developmentally dysplastic hip?
o Ileum has a steeper slope (socket not formed normally)
o Femur is at a higher insertion point.
what effect does the femur being at a higher insertion point have on the pelvis?
The higher position can break down the acetabular labrum when the hip is flexed over time and stimulate osteophyte formation.
Name two impingements of the hip joint
Cam and Pincer
occur in young people
what is a CAM impingement?describe the deformity
thickening of bone at the femoral neck where is meets the acetabulum (near labrum)
- “pistol grip” deformity
what effect does the CAM impingement have?
growth may hit the acetabular labrum and will ultimately affect deep flexion of the hip
this leads to labral tears and cartilage delamination
what is a pincer impingement? describe the deformity
socket may be too deep so increased flexion of the hip may lead to increased growth of the acetabular labrum causing a pincer growth protruding over the femoral head
what effect does the pincer impingement have?
the normal neck impacts the larger labrum leading to damage and increased ossification
how can the cam and pincer impingement be repaired?
Hip arthroscopies
- shave off the bumps or inappropriate appositional bone growth.
what is the role of the ACL?
prevents anterior displacement of the femur.
or hyperextension of the knee
what is a synovial joint?
a joint containing:
- synovial fluid
- articular cartilage
- synovial membrane
- all surrounded by an articular capsule.
what risk goes up with an ACL rupture?
the risk of meniscal injuries goes up as the menisci resist the femur sliding backward (act as shock absorbers)
what are the layers of articular cartilage? describe the fibres inside each layer
1) superficial gliding zone
- horizontal fibres
2) middle transitional zone
- fibres are more random and oblique
3) deep radial zone
- fibres are vertical
4) tidemark
subcondral bone
cancellous bone
what is done when a meniscus cannot be re-woven back together?
what is the impact on the blood supply?
the blood supply cannot be re-initiated
so a partial medial meniscectomy can remove a ruptured meniscus
what is the significance of the meniscus in pressure distribution of the knee?
the menisci act to distribute compressive forces so without one, all the forces are targeted at one focal point on the tibia
little meniscus left over accelerates arthritis
ultimate outcome will be a total/partial knee replacement.
what is the function of the PCL?
prevent posterior displacement of tibia to femur
what is the role of the menisci?
resist compressive forces, prevent over rotation of the tibia to femur.
