ICD-10-CM > S00-T88 > S80-S89 > S86 > S86.3 > S86.31 S86.31 Strain of muscle(s) and tendon(s) of peroneal muscle group at lower leg level Non-Billable/Non-Specific Codes S86.311Strain of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, right legS86.311A..., initial encounterS86.311D..., subsequent encounterS86.311S..., sequelaS86.312Strain of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, left legS86.312A..., initial encounterS86.312D..., subsequent encounterS86.312S..., sequelaS86.319Strain of muscle(s) and tendon(s) of peroneal muscle group at lower leg level, unspecified legS86.319A..., initial encounterS86.319D..., subsequent encounterS86.319S..., sequela