Most Hip and Knee Revisions Now Group to Wound Debridement (MS-DRG V44.0)
MS-DRG V44.0 retired the hip and knee revision DRGs 466-468 and created DRG 449, Revision of Hip or Knee Prosthesis. Most revisions do not group there.
The most common way to code a revision, removing the old prosthesis and inserting a new one, now groups to DRGs 463-465, Wound Debridement or Skin Graft Except Hand for Musculoskeletal and Connective Tissue Disorders. DRG 449 receives only revisions coded with the single "revision" root operation.
CMS made this change on purpose. In the FY 2027 final rule, it removed the logic that sent remove-and-replace code pairs to 466-468 and said those cases would redistribute to 463-465, using the same hip code pair we test below as its example. Commenters asked CMS to keep 466-468, and the American Hospital Association warned that the shift into the debridement DRGs would hurt data comparability over time. CMS acknowledged that the 463-465 titles do not describe orthopedic procedures, but answered that "we do not believe that there is a clinical coherence issue to address."
The change took effect October 1, 2026. It splits payment for the same surgery depending on how the procedure is coded.
The Same Surgery, Grouped Through Every Version
We grouped identical claims through every MS-DRG version from V40.0 to V44.0. The patient is a 72-year-old woman with mechanical loosening of a right hip prosthesis (T84.030A), discharged home. For V40.0 through V43.1 the result never changes. V44.0 is the first version that moves it.
| Claim | V40.0 to V43.1 | V44.0 | Relative weight, V43.1 to V44.0 |
|---|---|---|---|
Hip remove and replace (0SP90JZ + 0SR9019), no CC/MCC |
468 | 465 | 2.7480 to 2.4822 (-9.7%) |
| Hip remove and replace, with CC | 467 | 464 | 3.5266 to 3.1764 (-9.9%) |
| Hip remove and replace, with MCC | 466 | 463 | 5.2054 to 5.1296 (-1.5%) |
Knee remove and replace (0SPC0JZ + 0SRC0J9), no CC/MCC |
468 | 465 | 2.7480 to 2.4822 (-9.7%) |
Hip revision coded as 0SW90JZ, no CC/MCC |
468 | 449 | 2.7480 to 3.2995 (+20.1%) |
Hip removal only, spacer stage (0SP90JZ) |
465 | 465 | 1.8237 to 2.4822 (+36.1%) |
Primary hip replacement (0SR9019, M16.11) |
470 | 470 | 1.9289 to 1.9563 (+1.4%) |
The last two rows are controls. Removal on its own has grouped to 465 in every version, and a primary replacement stays in 470. Only the revisions moved.
Why Remove-and-Replace Lands in Debridement
MS-DRG surgical logic picks the highest-ranked surgical DRG that any procedure on the claim qualifies for. In V43.1, Appendix E of the Definitions Manual listed removal plus replacement as a procedure cluster: the pair together qualified for 466-468, which outranked everything else the codes qualified for separately.
Removal of a hip or knee prosthesis has also qualified for 463-465 on its own for years. That is why a first-stage spacer procedure, with no new prosthesis, has always grouped there.
V44.0 removed the cluster. The pair no longer counts as a revision, so each code is evaluated alone. The removal code qualifies for 463-465, which outranks the 469-470 replacement DRGs the new prosthesis would reach. The grouper's output marks both codes as affecting the DRG under V43.1, and only the removal code under V44.0.
CMS also renamed 463-465 from "Debridement and Skin Graft" to "Debridement or Skin Graft", noting that "and" wrongly suggested both were required. The rename did not cause the move, but it makes the title fit the family a little better.
DRG 449 contains only the 0SW "Revision of Synthetic Substitute" codes. A revision documented and coded as one revision procedure gets there. A revision coded as removal and replacement does not.
The Numbers Behind It
CMS publishes its FY 2025 Medicare claims grouped under both versions in the files that accompany the FY 2027 final rule. Nationally:
| DRGs | Under V43 | Under V44 |
|---|---|---|
| 466-468, Revision of Hip or Knee Replacement | 37,931 | retired |
| 449, Revision of Hip or Knee Prosthesis | 986 | |
| 463-465, Wound Debridement or Skin Graft, musculoskeletal | 12,440 | 42,154 |
About 30,000 revision cases moved into the debridement family. Less than 3% of the old revision volume reached the DRG with "revision" in its title.
CMS set the FY 2027 weights on the regrouped claims, so the debridement family's weights already reflect the revision cases now in it. DRG 465 rose 36.1%, DRG 464 rose 2.0%, and DRG 463 fell 10.00%, the most a weight can drop in one year. Revisions are paid on a blended weight for a family that now mixes joint revision with wound debridement.
Periprosthetic Joint Infection Has Its Own Rules
V44.0 also created DRGs 403 and 404 for hip or knee procedures with a principal diagnosis of periprosthetic joint infection (PJI), and DRG 400 for other knee infections. Both depend on the procedure as well as the diagnosis.
| Claim, all with principal diagnosis of PJI | V43.1 | V44.0 | Relative weight, V43.1 to V44.0 |
|---|---|---|---|
| Hip remove and replace, no CC/MCC | 468 | 404 | 2.7480 to 3.2513 (+18.3%) |
| Hip remove and replace, with CC | 467 | 404 | 3.5266 to 3.2513 (-7.8%) |
| Hip or knee remove and replace, with MCC | 466 | 403 | 5.2054 to 5.0061 (-3.8%) |
| Knee removal only, spacer stage, with MCC | 463 | 403 | 5.6995 to 5.0061 (-12.2%) |
Knee liner exchange coded 0SWC0JZ, with MCC |
466 | 449 | 5.2054 to 3.2995 (-36.6%) |
Knee joint drainage (0S9C0ZZ), with MCC |
485 | 488 | 3.2271 to 2.2211 (-31.2%) |
- PJI does not always pay more. With an MCC, a PJI remove-and-replace groups to 403 at 5.0061, while the same surgery without PJI groups to 463 at 5.1296. PJI adds the most where the case has no MCC.
- A liner exchange for PJI goes to 449, not 403. The
0SWrevision codes are not on the 403-404 procedure list, so a debridement, antibiotics and implant retention (DAIR) procedure coded as a revision groups to 449 whatever the diagnosis. - A knee washout for PJI is grouped as "without infection". DRG 400 no longer treats PJI as a knee infection, and joint drainage and excision are not on the 403-404 list. The case falls to 488, Knee Procedures without Principal Diagnosis of Infection.
What to Check Now
- Find your revisions. Pull FY 2027 discharges with a hip or knee prosthesis removal and replacement. Expect them in 463-465, not 449. Revision volume reports, implant cost reports and service line dashboards keyed on DRG number will undercount.
- Know how your coders code revisions. Remove-and-replace and the
0SWrevision root operation now group to different DRGs at different weights. The choice has to follow the operative report. A pattern that favors the higher-paying option is the kind of thing payer audits look for. - Expect audit questions on 463-465. A reviewer who sees a hip revision in a wound debridement DRG may flag it as a mismatch. The answer is the V44.0 grouping logic, and it helps to have it written down before the request arrives.
- Do not assume PJI is the high-value query. It moves cases with no CC or MCC up, but it can lower an MCC case and does nothing for a DAIR coded as a revision.
- Hold September discharges on V43.1. A rebill for a stay discharged before October 1 still groups to 466-468.
Test It Yourself
Every claim above can be reproduced in the MS-DRG grouper. Enter the codes, group under V44.0, then switch the version dropdown to V43.1 and group the same claim again. The per-code pages show the logic too: 0SP90JZ lists its DRG assignments by version, and DRG 449 and DRG 465 show their weights across every version we support.
For inquiries, email [email protected].
Groupings were run on the CMS MS-DRG grouper software for V40.0 through V44.0. CMS's reasoning and the public comments are in the FY 2027 IPPS/LTCH PPS final rule, 91 FR 49570 (August 4, 2026), section II.C. Claim counts come from the FY 2027 IPPS final rule correction notice AOR/BOR files, which group FY 2025 MedPAR claims under V43 and V44. Procedure logic is from Appendix E and the MDC 08 tables of the V43.1 and V44.0 Definitions Manuals. Relative weight is not payment: actual reimbursement also applies the wage index, capital, DSH and IME adjustments, and outlier payments.