ABNORMAL MEDIAL LOADING

Question 1

• Widened base of gait to support weight

o Directs center of gravity more medially
o Weight is now distributed medially prematurely during gait

▪ Results in STJ pronation during stance phase

Answer 1

Obesity

Question 2

• Femur externally rotated results in foot being externally rotated
• If foot is externally rotated excessively → results in medial direction of center of gravity

Answer 2

External Femoral Torsion

Question 3

• Normal external rotation of ankle joint with hip at neutral and tibia in the frontal plane is 13-18⁰

o At heel strike, foot is normally abducted 8-15⁰
o If tibia is externally rotated more than 18⁰ → foot will be excessively abducted

• If tibia is externally rotated >20⁰ the foot will be excessively abducted during locomotion

o STJ pronation will be clinically evident

▪ Directs center of gravity medially → pronating STJ through stance phase

Answer 3

External Tibial Torsion

Question 4

• Tibia angulated in valgus, or everted when viewed in frontal plane

o Resulting angulation causes center of gravity to be directed medially
o Also results in calcaneus being everted which predisposes the STJ to pronation to compensate

Answer 4

Tibial Valgum (knock kneed)

Question 5

• Will result in increased transverse plane motion of the forefoot on the rearfoot

o When forefoot is pronated about OMTJ, it is abducted on the rearfoot
o This excessive abduction directs force medially exerting a pronatory force on the STJ

Answer 5

Vertical OMTJ Axis

Question 6

• Foot normally should be supinated at the end of swing phase, entering into contact period of stance phase
• If pronated at end of swing phase → enters contact pronated

o Force is already directed medially maintaining STJ in a pronation position through stance phase

▪ Anterior Tibialis dysfunction can cause this

Answer 6

Foot pronated at end of swing phase