Limb Deformity Analysis: How to perform

Last updated on January 17 2024

Description

Leg deformity is an abnormal size, shape, position, or composition of a limb, which may be congenital and inherited or an acquired defect.

The Limb Deformity Analysis procedure can be used to correct the limb alignment, which requires knowledge of certain anatomical measurements. This procedure is intended to provide the necessary information and allow the pediatrician to have a better understanding of the clinical condition of their patient.

Measurements

The measurements made by the procedure are displayed in the image:

• Joint Line Congruence Angle (JLCA): the angle between the lines of the femur and tibia plateau;
• Mechanical Axis (MA): is the total leg length, i.e., the length between the center of the femoral head and the tangent line of the tibial distal articular surface.
• Mechanical Axis Deviation (MAD): Perpendicular distance from the center of the knee to the mechanical axis, i.e. the length between the midpoint of the tibial surface and the mechanical axis;
• Mechanical Axis of the Femur (MAF): is the femur length, i. e., the length between the center of the femoral head and the midpoint of the femur plateau;
• Mechanical Axis of the Tibia (MAT): is the tibial length, i. e., the length between the tangent line of the tibial distal articular surface and the midpoint of the tibial plateau;
• Mechanical Lateral Distal Femoral Angle (mLDFA): the angle between the femoral condyles and the femoral mechanical axis, measured on the lateral side;
• Mechanical Lateral Distal Tibial Angle (mLDTA): the angle between the tangent line of the tibial distal articular surface and the tibial mechanical axis, measured on the lateral side;
• Mechanical Lateral Proximal Femoral Angle (mLPFA): the angle between the line starting in the center of the femoral head and ending in the greater trochanter and the femoral mechanical axis, measured on the lateral side;
• Mechanical Medial Proximal Tibial Angle (mMPTA): the angle between the tibial plateau and the tibial mechanical axis, measured on the medial side;
• Mechanical Tibiofemoral Angle (mTFA): The angle between the line from the center of the femoral head to the center of the femoral articular surface and the line from the center of the tibial plateau to the center of the tibial distal articular surface.
• Limb Length Discrepancy (LLD): the difference between the length of both LTL.

Auxiliary references 

To show this procedure, PeekMed® needs additional references:

• Anatomical Axis of the Femur (AAF): a line that passes through the midpoint of femur proximal cortex and the midpoint of femur distal cortex.
• Hilgenreiner’s line: a horizontal line through the teardrops (or triradiate cartilage in children) of the acetabulum;
• Lesser Trochanters’ Line (LTL): a perpendicular line to the Hilgenreiner’s line, finishing at the medial edge of each lesser trochanter.

How to perform

After selecting this procedure in the sidebar, you must mark the points to conclude it. To see the caption of each point you need to click on this button .