ICD-10-CM > M00-M99 > M20-M25 > M25 > M25.1 > M25.17 M25.17 Fistula, ankle and foot Non-Billable/Non-Specific Codes M25.171Fistula, right ankleM25.172Fistula, left ankleM25.173Fistula, unspecified ankleM25.174Fistula, right footM25.175Fistula, left footM25.176Fistula, unspecified foot