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MS-DRG 449 · MDC 08 · Surgical

MS-DRG 449: Revision of Hip or Knee Prosthesis

Reviewed by QuickIntell RCM Editorial Team · Last reviewed

Data effective
Data currency: IPPS Table 5 FY2027 final rule (effective October 1, 2026); Definitions Manual v44 (effective October 1, 2026). Next CMS release: April 1, 2027 (v44.1 mid-year update), then the FY2028 final rule in August 2027.

Key facts for DRG 449

FY2027 relative weight
3.3000
Higher than 81% of all MS-DRGs
Change vs FY2026
New DRG
No FY2026 weight
Geometric mean LOS
3.1 days
Arithmetic mean 4.8 days
MDC
08
Diseases and Disorders of the Musculoskeletal System and Connective Tissue
Severity level
single severity level
Transfer policy
Not a transfer DRG

TL;DR

MS-DRG 449 is a surgical group in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue) at a single-severity group of its family. CMS assigns it a FY2027 relative weight of 3.3000 with a geometric mean length of stay of 3.1 days and an arithmetic mean of 4.8. It is new for FY2027, so there is no prior-year weight to compare. That weight is higher than 81% of all surgical and medical MS-DRGs. CMS does not split this group by severity. The v44 Definitions Manual assigns it through 42 operating room procedures codes.

What changed from FY2026 to FY2027

DRG 449 is new in the v44 grouper effective October 1, 2026, so there is no FY2026 weight to compare. Review the FY2027 final rule Table 6 series for the code moves that created it and confirm that your encoder and contract modeling have loaded v44.

CC and MCC family

DRG 449 stands alone: CMS does not split this base group by CC or MCC severity, so complication documentation does not move the assignment, although it still affects quality and risk-adjustment reporting.

Grouper logic (v44 Definitions Manual)

Operating Room Procedures: 42 ICD-10 codes drive assignment to this group; the first 12 are shown.

Operating Room Procedures codes assigned to DRG 449 (sample)
ICD-10 codeDescription
0SW90JZRevision of Synthetic Substitute in Right Hip Joint, Open Approach
0SW93JZRevision of Synthetic Substitute in Right Hip Joint, Percutaneous Approach
0SW94JZRevision of Synthetic Substitute in Right Hip Joint, Percutaneous Endoscopic Approach
0SWA0JZRevision of Synthetic Substitute in Right Hip Joint, Acetabular Surface, Open Approach
0SWA3JZRevision of Synthetic Substitute in Right Hip Joint, Acetabular Surface, Percutaneous Approach
0SWA4JZRevision of Synthetic Substitute in Right Hip Joint, Acetabular Surface, Percutaneous Endoscopic Approach
0SWB0JZRevision of Synthetic Substitute in Left Hip Joint, Open Approach
0SWB3JZRevision of Synthetic Substitute in Left Hip Joint, Percutaneous Approach
0SWB4JZRevision of Synthetic Substitute in Left Hip Joint, Percutaneous Endoscopic Approach
0SWC0JCRevision of Synthetic Substitute in Right Knee Joint, Patellar Surface, Open Approach
0SWC0JZRevision of Synthetic Substitute in Right Knee Joint, Open Approach
0SWC3JCRevision of Synthetic Substitute in Right Knee Joint, Patellar Surface, Percutaneous Approach

Documentation and denial exposure

As a surgical DRG, assignment depends on a qualifying operating-room procedure being coded from the operative report; a missing or non-OR procedure code drops the stay into a medical DRG in MDC 08 with a lower weight. Because this family has no severity split, review risk concentrates on medical-necessity of the admission itself and on the two-midnight benchmark. Typical inpatient denial codes for this group: CARC 16 (claim lacks information needed to group the stay), CARC 50 (the admission or procedure is judged not medically necessary), CARC 97 (a service is bundled into the DRG payment).

How QuickIntell uses DRG 449 data

QuickCode groups inpatient encounters against the current v44 logic, flags CC and MCC candidates that lack supporting documentation, and shows the weight difference across the family before the claim drops. QuickScribe captures the attending's language that supports severity, and QuickRCM works DRG-validation denials with the grouper evidence attached.

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Frequently asked questions — DRG 449

What is MS-DRG 449?

MS-DRG 449 is "Revision of Hip or Knee Prosthesis", a surgical Medicare Severity Diagnosis-Related Group in MDC 08, Diseases and Disorders of the Musculoskeletal System and Connective Tissue. Medicare pays inpatient stays grouped here at the hospital's base rate multiplied by the DRG relative weight.

What is the FY2027 relative weight for DRG 449?

The FY2027 relative weight is 3.3000 (IPPS final rule Table 5, effective October 1, 2026). The DRG is new for FY2027.

What is the average length of stay for DRG 449?

CMS reports a geometric mean length of stay of 3.1 days and an arithmetic mean of 4.8 days for FY2027. The geometric mean is used for transfer-payment calculations.

What documentation supports the severity level of DRG 449?

DRG 449 has no CC or MCC sibling, so secondary-diagnosis capture does not change the group or its weight. Review effort belongs instead on the principal diagnosis sequencing and the procedure codes that place the stay in this group, and on medical necessity of the inpatient admission itself under the two-midnight benchmark, which is where denials for single-severity groups concentrate.

Which codes group to DRG 449?

The v44 Definitions Manual lists 42 operating room procedures codes for this group. Examples from the operating room procedures list: 0SW90JZ (Revision of Synthetic Substitute in Right Hip Joint, Open Approach); 0SW93JZ (Revision of Synthetic Substitute in Right Hip Joint, Percutaneous Approach); 0SW94JZ (Revision of Synthetic Substitute in Right Hip Joint, Percutaneous Endoscopic Approach); 0SWA0JZ (Revision of Synthetic Substitute in Right Hip Joint, Acetabular Surface, Open Approach).

Is DRG 449 a post-acute transfer DRG?

No. DRG 449 is not on the FY2027 post-acute care transfer list, so the transfer per-diem policy does not apply to it.

Sources

Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-01. Verify against the primary file before billing or contracting decisions.

Disclaimer

This page is an operational reference compiled from the CMS IPPS FY2027 final rule (Table 5) and the v44 ICD-10 MS-DRG Definitions Manual. Relative weights are national factors; actual payment depends on each hospital's wage-adjusted base rate, add-ons, outliers and transfer adjustments. Nothing here is legal, clinical or billing advice; verify grouping against your encoder and the published CMS files.