550 — Septic Arthritis without CC/MCC

MS-DRG 550, Septic Arthritis without CC/MCC, is a medical DRG in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue) under MS-DRG version 44.0, which applies to inpatient discharges from October 1, 2026 through September 30, 2027.

Its FY2027 relative weight is 0.8591, so Medicare's base payment for this DRG is about 0.86 times the average inpatient case (below average), before hospital-specific adjustments. The geometric mean length of stay is 2.8 days and the arithmetic mean is 3.5 days.

It belongs to a 3-level severity family: DRG 548 (with MCC, weight 1.9519), DRG 549 (with CC, weight 1.1435) and DRG 550 (without CC/MCC, weight 0.8591). The highest-severity level carries 2.3 times the weight of the lowest, which is why documenting CC and MCC conditions matters.

155 ICD-10-CM diagnosis codes are part of this DRG's grouping logic; they are listed below.