The Arthritis Eleven - 09.03.2020

Question 1

Recall Wolff’s law

Answer 1

• Wolff’s Law of transformation of bone - If loading on a particular bone increases, the bone will remodel itself over time to become stronger to resist that sort of loading.
• Exercise leads to maintenance of stronger trabecular network

Question 2

Exercise and osteoarthritis

Answer 2

• ## there is evidence that a lot of the same exercise (e.g. soccer) causes osteoarthritis.

Question 3

Describe the structure and function of articular cartilage

Answer 3

• superficial gliding zone (10-20%)
• middle transitional zone (40-60%)
• deep x zone (30%)
• tidemark (border between non-calcified and calcified cartilage)

Question 4

outline the role of mechanic in osteoarthritis

Answer 4

• OA is a mechanical disease
• it is related to movement ad physical forces
• pathophysiological response to mechanical injury

Question 5

Varus and Valgus malalignment

Answer 5

varus = O-legs/bow logs (more stress on the medial compartment)
valgus = X-legs/knock-kneed (more stress on the lateral compartment)

(genu valgum - gum holds the knees together; gene varum - there is a bottle of rum holding the knees apart)

Question 6

Exercise and osteoarthritis

Answer 6

• there is evidence that a lot of the same exercise (e.g. soccer) causes osteoarthritis.
• it is good to do different types of sport during childhood

Question 7

What is associated with playing soccer (in childhood)?

Answer 7

• bow legs

Question 8

Osteotomy of the knee - when?

Answer 8

• To transfer weight from the arthritic part of the knee to a healthier area
• To correct poor knee alignment
• To prolong the life span of the knee joint, delay the need for joint replacement

Question 9

What happens to trabecular bone with age?

Answer 9

trabeculae get thinner

Question 10

DDH

Answer 10

Developmental dysplasia of the hip

• affects babies
• can be due to breach birth, low amniotic fluid, females being more sensitive to hormones, perhaps linked too in utero behaaviour such as kicking
• screening: ultrasound
• The bone is not in the right place
• if it is not in the right place it will not respond properly

Question 11

DDH

Answer 11

Developmental dysplasia of the hip

• condition where the “ball and socket” joint of the hip does not properly form in babies and young children.
• the socket of the hip is to shallow and the femoral head is not held tightly in place
• affects babies
• can be due to breech birth, low amniotic fluid, females being more sensitive to hormones, perhaps linked too in utero behaviour such as kicking
• screening: ultrasound of the baby’s hip
• The bone is not in the right place
• if it is not in the right place it will not respond properly

Treatment: keep legs in a flexed position e.g. stent to harness

• surgery needed if diagnosed after 6m of age
• in africa, when women carry their babies on their backs the legs are in a flexed position so that helps treat the problem.

Question 12

DDH

Answer 12

Developmental dysplasia of the hip

• condition where the “ball and socket” joint of the hip does not properly form in babies and young children.
• the socket of the hip is to shallow and the femoral head is not held tightly in place
• affects babies
• can be due to breech birth, low amniotic fluid, females being more sensitive to hormones, perhaps linked too in utero behaviour such as kicking
• screening: ultrasound of the baby’s hip
• The bone is not in the right place
• if it is not in the right place it will not respond properly

Treatment: keep legs in a flexed position e.g. stent to harness

• surgery needed if diagnosed after 6m of age
• in africa, when women carry their babies on their backs the legs are in a flexed position so that helps treat the problem.

Question 13

Cam hips

Answer 13

Cam Impingement:

• A cam impingement occurs when excessive bone grows at the edge of the femoral head, where it meets a part of the femur called the femoral neck.
• gun shape
• The excessive bone growth forms a bump, which can do one or both of the following:
  • Prevent the femoral head from fully rotating in its socket.
  • Rub against the cartilage located inside the hip’s socket, causing damage to the cartilage.
• Cam impingement is most common in young men.1

Question 14

Pincer hip

Answer 14

Pincer impingement:

• A pincer impingement occurs when excessive bone grows at the edge of the hip’s socket.
• The excess bone creates an overhang, making the socket too deep in certain places.
• The excessive bone tissue can
  • Prevent the femoral head from rotating in its socket.
  • Cause the hip’s labrum to become pinched.
• Pincer impingement tends to be most common in middle-aged women.1,2

Question 15

What are some implications of Wolff’s law?

Answer 15

• Astronauts: weaker bone
• ## Tennis players: dominant arm, bone is 20% thicker than the other arm

Question 16

What are some implications of Wolff’s law?

Answer 16

• Astronauts: weaker bone
• ## Tennis players: dominant arm, bone is 20% thicker than the other arm

Question 17

What is a way to measure the knee deformities?

Answer 17

ICIM

Intercondylar distance
intermalleolar distance