Unequal limb length (acquired), unspecified femur

This code signifies an acquired difference in the length of the lower limbs, where the specific femur involved (left or right) is not documented. This condition can lead to gait abnormalities, back pain, and other musculoskeletal issues. It is distinct from congenital limb length discrepancies.

Use this code when documentation indicates an acquired unequal limb length, and the physician's notes do not specify which femur is shorter or longer. This often occurs when the laterality is not clearly identified in the diagnostic statement or assessment. Supporting documentation would include physical examination findings, imaging reports (e.g., scanogram), and physician's assessment of limb length discrepancy.

• Always seek clarification from the provider if the laterality of the femur is not specified to allow for a more precise code.
• Distinguish between acquired (M21.7-) and congenital (Q73.8, Q74.3) limb length discrepancies.
• Do not use this code if the laterality (left or right femur) is clearly documented; instead, select the more specific M21.751 (right) or M21.752 (left).