Posterior tibial tendinitis, right leg

This code signifies inflammation of the posterior tibial tendon in the right lower extremity. This condition often presents as pain and swelling along the inner ankle and arch, potentially leading to acquired flatfoot if left untreated.

Use this code when documentation clearly indicates a diagnosis of tendinitis affecting the posterior tibial tendon specifically in the right leg. Supporting documentation should include a physician's diagnosis based on clinical examination, imaging findings (e.g., MRI, ultrasound) confirming tendinitis, or a detailed description of symptoms localized to the right posterior tibial tendon.

• Ensure laterality is explicitly documented as "right" to avoid unspecified or bilateral coding.
• Differentiate from other ankle/foot tendinitis codes (e.g., peroneal, Achilles) based on anatomical location.
• Consider additional codes for associated conditions like acquired flatfoot (M21.4-) if present and documented.