What are the three basic elements of rating for knee disability?

• A. Limitation of flexion and extension, instability and calf atrophy.
• B. Limitation of flexion and extension, instability and thigh atrophy.
• C. Adduction, abduction and calf atrophy
• D. Adduction, abduction and thigh atrophy

Answer: (B)

Rating knee disability hinges on three main factors: the amount of knee motion (limitations in flexion and in extension), the joint’s stability (whether ligamentous structures cause instability), and the condition of surrounding muscles (thigh atrophy reflecting quadriceps weakness). Limitation of flexion and extension shows how much the knee’s movement is restricted, while instability reveals the tendency of the knee to give way due to ligament laxity. Thigh atrophy indicates muscle wasting that can worsen function and gait. Adduction and abduction are not standard primary measures for knee impairment, and calf atrophy is less directly related to knee rating than thigh muscle wasting. Hence, the combination of restricted flexion/extension, instability, and thigh atrophy best describes the three basic elements.