S88.121S
Partial traumatic amputation at level between knee and ankle, right lower leg, sequela
S88.121S (also written S88121S) is a billable ICD-10-CM diagnosis code for partial traumatic amputation at level between knee and ankle, right lower leg, sequela. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 54 codes in category S88 (Traumatic amputation of lower leg). Its 7th character, S, means sequela. Its coding notes include a Use additional code instruction, 1 Excludes1 entry and 6 Excludes2 entries.
7th character
Category S88 requires a 7th character.
Guidelines tips
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
The 7th character depends on whether the patient is in active treatment, not on who sees the patient. An aftercare Z code is not used for injury aftercare.
Each injury gets its own code unless a combination code exists, with the most serious injury first. Superficial injuries at the same site as a more severe injury are not coded. Injuries during medical care are coded as complications.
Use additional code
Add the listed code as a secondary code, if known.
Also from chapter/block level (1 note)
- code to identify any retained foreign body, if applicable (Z18.-)
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (6 notes)
- birth trauma (P10-P15)
- obstetric trauma (O70-O71)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the Musculoskeletal Rehabilitation clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026IRF 60% Rule
On the CMS list of diagnoses used to determine presumptive compliance with the IRF 60 percent rule.
Source: CMS IRF Presumptive Compliance-3, FY 2027 IRF PPS final rule files, effective for discharges on or after October 1, 2026Notes
Also from chapter/block level (2 notes)
- Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
- The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.