Mechanical axis deviation
Also written as: MAD — Mechanical Axis Deviation
Abnormal alignment of the weight-bearing axis of the lower extremity from the normal hip-to-ankle line.
Full Definition
Mechanical axis deviation (MAD) refers to the displacement of the mechanical axis of the lower extremity from its normal pathway connecting the center of the femoral head to the center of the ankle joint. In normal alignment, this line passes through or near the center of the knee joint. MAD is measured as the distance between the mechanical axis line and the center of the knee, with medial deviation indicating varus malalignment and lateral deviation indicating valgus malalignment. This measurement is crucial in assessing post-traumatic deformities, planning corrective osteotomies, and evaluating the biomechanical consequences of fracture healing.
Usage
Usage note: Requires measurement specification and direction for clinical relevance.
In Context
- "Long leg radiographs demonstrated 15mm of medial mechanical axis deviation following tibial malunion." — Deformity analysis report
- "Correction of the mechanical axis deviation required a precise opening wedge osteotomy." — Surgical planning documentation