ICD-10-CM > M00-M99 > M70-M79 > M76 > M76.8 > M76.82 M76.82 Posterior tibial tendinitis Non-Billable/Non-Specific Codes M76.821Posterior tibial tendinitis, right legM76.822Posterior tibial tendinitis, left legM76.829Posterior tibial tendinitis, unspecified leg