• Line between the

center of the femoral

head and the center of

the knee joint (between

both femoral condyles).

• A mid diaphyseal line

passing along the

length of the

intramedullary canal.

- It extends between center of the femoral

head and the center of the tibial plafond.

- Lines represent the

orientation of the joint in

certain plane.

- Knee Joint

- Along the subchondral line of

the tibial plateau.

- Line tangential to the most

distal point of the femoral

condyles.

Normally joint lines are parallel within 2

degrees.

Angles greater than 2 degrees are

considered as a source of mechanical axis

deviation (MAD).

-Angle between:

-Line along the

mechanical axis of the

femur and line along

the distal point of the

femoral condyles

- Normal range is 85-

90 degrees.

-Angle between:

-Line along the

mechanical axis of

the tibia and line

along the tibial

plateau.

- Normal range is

85- 90 degrees.

In cases of deformity:-- Angle between the distal tibial mechanical axis and

line along the tibial plafond.

- If one side is normal then it is used as a template

for the deformed site.

- If both are deformed then consider normal angles.

- (Center of rotation angle).

- Point at which proximal and distal axis

lines intersect.

- Osteotomy fracture is done at CORA site.

1- Measure mechanical

axes of both lower limbs.

2- Joint orientation lines.

3- LPFA and MPTA/LDTA.

4- CORA.

•THANK YOU