Algoneurodystrophy, unspecified thigh

This code represents algoneurodystrophy, also known as Complex Regional Pain Syndrome (CRPS) Type I, affecting an unspecified thigh. It describes a chronic pain condition characterized by severe, burning pain, swelling, and trophic changes in the affected limb, without evidence of nerve injury. The "unspecified" nature indicates the laterality (left or right) is not documented.

Use this code when documentation clearly indicates a diagnosis of algoneurodystrophy or CRPS Type I localized to the thigh, and the medical record does not specify whether it affects the left or right thigh. This code is appropriate when the provider has diagnosed the condition but has not provided laterality.

• Ensure documentation explicitly states "unspecified thigh" or lacks laterality for the thigh.
• If laterality is specified (left or right thigh), use the more specific codes M89.051 or M89.052.
• Distinguish from CRPS Type II (causalgia), which involves confirmed nerve injury and is coded differently.