T84.099A — Other mechanical complication of unspecified internal joint prosthesis, initial encounter
Is T84.099A billable?
Yes, but T84.099A will trip a Medicare edit. T84.099A is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, CMS lists T84.099A under Medicare Code Editor edit 20, “Unspecified code” — meaning a code specifying laterality (right, left or bilateral) exists in the same family. On an inpatient claim this triggers the edit, because CMS holds that there are very limited circumstances in which laterality cannot be documented.
More specific alternatives
- T84.090AOther mechanical complication of internal right hip prosthesis, initial encounter
- T84.091AOther mechanical complication of internal left hip prosthesis, initial encounter
- T84.092AOther mechanical complication of internal right knee prosthesis, initial encounter
- T84.093AOther mechanical complication of internal left knee prosthesis, initial encounter
- T84.098AOther mechanical complication of other internal joint prosthesis, initial encounter
T84.099A at a glance
| Code | T84.099A |
|---|---|
| Description | Other mechanical complication of unspecified internal joint prosthesis, initial encounter |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
| 7th character "A" | initial encounter |
What does the 7th character "A" mean in T84.099A?
In T84.099A, the 7th character A means initial encounter. The 7th character is required for T84.099A to be a valid, complete code.
Same condition, different episode of care — switch the 7th character:
What Medicare edits apply to T84.099A?
The Medicare Code Editor screens inpatient claims before they are grouped. These edits name T84.099A directly.
A code specifying laterality (right, left or bilateral) exists in the same family. CMS holds that there are very limited circumstances in which laterality cannot be documented.
Which MS-DRGs does T84.099A group to?
T84.099A sits in MDC 08 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 559Aftercare, Musculoskeletal System and Connective Tissue with MCCmedical
- 560Aftercare, Musculoskeletal System and Connective Tissue with CCmedical
- 561Aftercare, Musculoskeletal System and Connective Tissue without CC/MCCmedical
As a secondary diagnosis, T84.099A is a complication or comorbidity (CC), which can move a stay into a higher-paying DRG.
How is T84.099A listed in the Alphabetic Index?
The Alphabetic Index lists these routes under T84.099, the nearest indexed parent of T84.099A. Use them to find the family, then select the specific code.
- Complication › joint prosthesis, internal › mechanical › specified complication NEC (s) (from) (of)
Use additional code — inherited from Chapter 19
Report an additional code alongside T84.099A to fully describe the condition. T84.099A is sequenced first.
- code to identify any retained foreign body, if applicable (Z18.-)
Use additional code — inherited from T80-T88
Report an additional code alongside T84.099A to fully describe the condition. T84.099A is sequenced first.
Excludes2 — not included here — inherited from Chapter 19
The conditions below are not part of T84.099A, but a patient may have both at the same time. When documentation supports it, T84.099A and the excluded code may both be reported.
Excludes2 — not included here — inherited from T80-T88
The conditions below are not part of T84.099A, but a patient may have both at the same time. When documentation supports it, T84.099A and the excluded code may both be reported.
- any encounters with medical care for postprocedural conditions in which no complications are present, such as:
- artificial opening status (Z93.-)
- closure of external stoma (Z43.-)
- fitting and adjustment of external prosthetic device (Z44.-)
- burns and corrosions from local applications and irradiation (T20-T32)
- complications of surgical procedures during pregnancy, childbirth and the puerperium (O00-O9A)
- mechanical complication of respirator [ventilator] (J95.850)
- poisoning and toxic effects of drugs and chemicals (T36-T65 with fifth or sixth character 1-4 or 6)
- postprocedural fever (R50.82)
- specified complications classified elsewhere, such as:
- cerebrospinal fluid leak from spinal puncture (G97.0)
- colostomy malfunction (K94.0-)
- disorders of fluid and electrolyte imbalance (E86-E87)
- functional disturbances following cardiac surgery (I97.0-I97.1)
- intraoperative and postprocedural complications of specified body systems (D78.-, E36.-, E89.-, G97.3-, G97.4, H59.3-, H59.-, H95.2-, H95.3, I97.4-, I97.5, J95.6-, J95.7, K91.6-, L76.-, M96.-, N99.-)
- ostomy complications (J95.0-, K94.-, N99.5-)
- postgastric surgery syndromes (K91.1)
- postlaminectomy syndrome NEC (M96.1)
- postmastectomy lymphedema syndrome (I97.2)
- postsurgical blind-loop syndrome (K91.2)
- ventilator associated pneumonia (J95.851)
Excludes2 — not included here — inherited from T84
The conditions below are not part of T84.099A, but a patient may have both at the same time. When documentation supports it, T84.099A and the excluded code may both be reported.
How long has T84.099A existed?
T84.099A has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.