Flexion deformity, unspecified knee

This code signifies an abnormal, persistent bending or contracture of the knee joint, limiting its ability to fully extend. It indicates a fixed flexion of the knee, where the joint cannot be straightened to its normal anatomical position. The "unspecified" nature means the laterality (right or left) of the affected knee is not documented.

Use this code when documentation clearly states a "flexion deformity of the knee" without specifying whether it's the right or left knee. This often occurs in initial assessments or when the laterality is not yet determined or recorded. Supporting documentation includes physical exam findings noting limited knee extension, contractures, or a diagnosis of knee flexion deformity without laterality.

• Avoid using this code if the medical record specifies "right knee" or "left knee"; instead, use the more specific codes (M21.261 or M21.262).
• Ensure the documentation differentiates between a temporary inability to extend (e.g., due to pain or swelling) and a fixed structural deformity.
• Query the provider for laterality if possible to ensure the most specific code is reported.