Unequal limb length (acquired), unspecified tibia and fibula

This code signifies a noticeable difference in the length of the lower extremities that developed after birth, affecting the tibia and fibula, without further specification of the laterality (left or right leg). This acquired discrepancy can lead to gait abnormalities, back pain, and compensatory scoliosis.

Use this code when documentation indicates an acquired limb length discrepancy involving the lower leg bones (tibia and fibula), and the specific side (left or right) is not documented. This is appropriate for conditions such as post-traumatic growth arrest, surgical shortening, or developmental issues that manifest after birth.

• Ensure the documentation specifies "acquired" rather than congenital, which would necessitate a code from Q72.
• Avoid using this code if the laterality (left or right leg) is clearly documented; instead, use M21.761 or M21.762.
• Always look for an underlying cause for the acquired limb length inequality, such as a fracture or surgical intervention, and code it as a primary diagnosis if applicable.