AFC Arthritis Flashcards
Where do bones grow from?
Growth plate (epiphyseal plate)
State Hueter-Volkmann’s Law
Increased compression at the growth plate slows down longitudinal growth Increased tension at the growth plate speeds up longitudinal growth
Give an example of where Hueter-Volkmann’s Law can be used to correct an abnormality.
Eight Growth Plate – if there is abnormal growth on one side of the distal tibial physis you can inset a metal plate with pins on either side of the growth plate to prevent further growth on that side and allow the other side to catch up
What are the three different types of knee alignment?
Normal/Neutral - centre of the hip is over the centre of the knee which is over the centre of the foot Varus – bowed legs Valgus – knocked knees
What types of athletes get varus alignment?
Footballers
Which part of the knee joint would be loaded most in varus and valgus alignment?
Varus = The medial compartment Valgus = The lateral compartment
What are the consequences of varus and valgus alignment?
It will wear out the cartilage and cause osteoarthritis Varus x2 increase risk Valgus 1.5x increase risk
What surgical intervention can be performed before the onset of osteoarthritis to realign the knee joint?
Osteotomy – this involves taking a wedge out of the tibia to realign the knee joint
State Wolff’s Law.
Bone in a healthy person will adapt to the loads under which it is placed This means that cancellous/trabecular/spongy bone aligns along the major stress angles of the bone.
Give an example that illustrates Wolff’s law.
Surfer’s knots
What are the two surfaces of the cortical bone?
Periosteal surface Endosteal surface
Load on the bones causes an increase in cortical thickness – how is this response to loading different in children compared to adults?
Children – have an active periosteum and endosteum so they get increased bone growth at BOTH surfaces Adults – their periosteum is less active – so the response to increased loading is mainly at the endosteal surface
A lot of problems to do with body shape occur in utero. Give an example of such a problem that is associated with 9-10% of cases of osteoarthritis
Developmental Dysplasia of the Hip (DDH)
Describe the appearance of the hip joint in someone who had DDH.
The hip joint may be higher than normal The acetabulum is shallow and it doesn’t cover much of the femoral head This leads to increased load and wear
Why is it important to spot the deformities of DDH early?
If these deformities are caught early, they could realign them and cause a remodelling of the joint to allow normal stance