Valgus deformity, not elsewhere classified, left knee

This code identifies a valgus deformity affecting the left knee joint. This condition, commonly known as "knock-knee," involves an outward angulation of the lower leg relative to the thigh, causing the knees to touch while the ankles remain apart. It is a structural deviation of the knee that is not attributable to another specific, classified condition.

Apply this code when documentation explicitly states a valgus deformity of the left knee that is idiopathic or not secondary to a more specific diagnosis (e.g., fracture, arthritis). This code is appropriate for congenital, developmental, or acquired valgus deformities where the underlying cause is not otherwise specified. Supporting documentation should include physical exam findings noting the valgus angulation and laterality.

• Ensure documentation specifies "left knee" and confirms the deformity is valgus, not varus.
• Verify that no other more specific ICD-10-CM code exists for the underlying cause of the valgus deformity (e.g., post-traumatic, osteoarthritic).
• Do not confuse with M21.061 (right knee) or M21.069 (unspecified knee).