Which of the following is a component used to rate knee disability?

• A. Thigh atrophy
• B. Calf atrophy
• C. Carpal tunnel symptoms
• D. Hip mobility

Answer: (A)

Thigh atrophy is used because this proximal thigh muscle wasting directly reflects loss of strength around the knee, especially the quadriceps, which are essential for knee extension, stability, and gait. When the knee is injured or disabled, disuse and pathology can cause the thigh muscles to atrophy, and that decreased muscle mass translates into greater functional impairment. This makes thigh atrophy a meaningful component in rating knee disability.

Calf atrophy involves the lower leg and is less directly tied to knee function in standard rating methods. Carpal tunnel symptoms pertain to the wrist and hand, not the knee. Hip mobility relates to the hip joint; while hip function can influence knee mechanics, it is not a direct knee-specific rating component.