Valgus deformity, not elsewhere classified, unspecified knee

This code signifies an outward angulation of the lower leg relative to the thigh at the knee joint, commonly known as "knock-knee." It indicates a structural deviation where the knees touch or nearly touch while the ankles remain apart, without further specification of the underlying cause.

Use this code when documentation clearly states "valgus deformity of the knee" without specifying laterality (left or right) or a more specific etiology. This code is appropriate when the physician has not identified or documented the specific cause of the valgus deformity, such as a congenital condition, trauma, or arthritis.

• Avoid using this code if laterality (left or right knee) is documented; instead, choose the more specific M21.061 or M21.062.
• Do not use this code if a more specific underlying cause for the valgus deformity is identified (e.g., post-traumatic, congenital); code the underlying condition first, if applicable, and then the deformity.
• Ensure documentation supports the "unspecified" nature of the deformity and laterality before assigning this code.