The Knee

Question 1

Describe the normal tibiofemoral alignment.

Answer 1

Femoral shaft is 170 to 175 degrees laterally from tibial shaft.

*Slight physiological valgus is normal

Question 2

Describe genu valgum.

Answer 2

When the tibiofemoral alignment is less than 165 degrees.

“knock knees”

Question 3

Describe genu varum.

Answer 3

When tibiofemoral alignment greater than 180 degrees.

“Bow legs”

Question 4

What are the factors that lead to genu valgum?

Answer 4

1. Previous disease
2. Genetic predisposition
3. High body mass index
4. Laxity of ligaments
5. Abnormal alignment and muscle weakness at either end of the lower extremity.

Question 5

What does the genu valgum result in?

Answer 5

1. Increased stress on MCL, increased stress in lateral compartment
2. Excessive lateral tracking of the patella
3. Increased stress on ACL

Question 6

What are the factors that lead to genu varum?

Answer 6

1. Previous injury
2. Genetic predisposition
3. Laxity of ligaments
4. Abnormal alignment and muscle weakness at either end of the lower extremity
5. Thinning of articular cartilage on medial side can result in genu varum.

Question 7

What can be the result of a varus position of the knee?

Answer 7

1. Increased medial compartment loading
2. Greater loss of medial joint space
3. Increased strain on LCL