Other specified crystal arthropathies, right ankle and foot

This code signifies an inflammatory joint condition affecting the right ankle and/or foot, caused by the deposition of crystals other than those associated with gout (monosodium urate) or pseudogout (calcium pyrophosphate dihydrate). It encompasses various less common crystal-induced arthropathies, such as those caused by calcium oxalate or basic calcium phosphate crystals.

Use this code when documentation explicitly states a crystal arthropathy of the right ankle or foot that is not identified as gout or pseudogout. This diagnosis typically follows synovial fluid analysis or biopsy confirming the presence of specific crystal types. Documentation should clearly specify the affected joint(s) and the non-gout/non-pseudogout crystal etiology.

• Ensure the documentation specifies "other specified" crystal type and not simply "crystal arthropathy NOS" (not otherwise specified).
• Verify the laterality (right) and anatomical site (ankle and foot) are clearly documented.
• Do not use this code for gout (M10.-) or pseudogout (M11.1-) even if the specific crystal type is not fully identified.