Surgical · Hip

Open arthrotomy of the sacroiliac joint with tissue biopsy obtained from the joint itself.

Verified May 8, 2026 · 6 sources ↓

Medicare: $399.81
Work RVU: 4.62
Global, days: 90
Region: Hip

Drawn from CMSEmednyFastrvuNIHCgsmedicare

Documentation requirements

What must appear in the operative or office note to support the claim.

Source · Editorial brief grounded in 6 cited references ↓

Preoperative diagnosis with clinical rationale explaining why open arthrotomy biopsy was necessary over less invasive alternatives
Operative note specifying the surgical approach to the sacroiliac joint, including incision location and joint entry technique
Explicit documentation that an arthrotomy was performed — joint capsule was opened and entered, not merely approached percutaneously
Description of the tissue specimen obtained, anatomic location within the joint, and submission to pathology
Pathology report correlating to the specimen obtained at time of surgery
Documentation of laterality (right vs. left SI joint) to support LT or RT modifier when applicable

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 24 Unrelated E/M during global 25 Significant separate E/M 50 Bilateral procedure 51 Multiple procedures 52 Reduced services 57 Decision for surgery 58 Staged or related 59 Distinct service 62 Co-surgeons 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon AS PA/NP/CNS assistant LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 27050 describes an open surgical approach to the sacroiliac joint — the articulation between the sacrum and iliac bone of the pelvis — in which the surgeon incises into the joint space and excises a tissue specimen for pathologic analysis. This is a true arthrotomy, not a percutaneous or image-guided needle biopsy; the joint capsule is opened under direct visualization. Common indications include suspected infection, inflammatory arthropathy, or neoplastic involvement of the SI joint where less invasive sampling has been inconclusive or is not feasible.

The 90-day global period means the surgical package covers the day-before preoperative visit, the procedure itself, and all routine postoperative care through day 90. Any E/M service during that window for unrelated conditions requires modifier 24; a separately identifiable E/M on the day of surgery requires modifier 25 on the E/M. Staged or unrelated procedures in the global window need modifier 79; complications requiring a return to the OR for a related procedure use modifier 78.

Site of service matters here. The HOPD and ASC payment rates differ substantially — see the Site of Service comparison on this page. For bilateral cases (rare but documented in symmetric inflammatory disease), modifier 50 applies and Medicare reimburses at 150% of the single-procedure allowable billed on one claim line.

RVU & reimbursement

Component RVUs and Medicare national rate. Actual payment varies by GPCI locality.

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU vs. total RVU

The work RVU (4.62) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (11.97) adds practice overhead and malpractice, and is what drives the Medicare payment below.

Work RVU	4.62
Practice expense RVU	6.35
Malpractice RVU	1
Total RVU	11.97
Medicare national rate	$399.81
Global period	90 days

Payment by site of service

Medicare pays different rates by setting. HOPD typically pays substantially more than ASC for the same procedure.

Source · CMS OPPS Addendum B·ASC HCPCS payment rates·2026

Setting	Medicare rate (national)
Office (PFS non-facility) Procedure performed in physician's office	$399.81
HOPD (APC 5112) Hospital outpatient department	$1,642.82
ASC (PI A2) Ambulatory surgical center (freestanding)	$872.87

Common denial reasons

The recurring reasons claims for CPT 27050 get rejected.

Source · Editorial brief grounded in CMS NCCI edits, AAOS coding appeals, and cited references ↓

Medical necessity not established — payer requires documentation that less invasive biopsy methods were attempted or contraindicated before approving open arthrotomy
Operative note lacks explicit confirmation of arthrotomy (joint capsule entry), causing downcode to a soft-tissue biopsy code such as 27040 or 27041
Laterality modifier missing or inconsistent with imaging and clinical documentation, triggering edit-based denial
Bundling with same-session SI joint injection codes (G0259, G0260) without a modifier establishing distinct procedural intent
Global period conflict — postoperative E/M billed without modifier 24 when the visit is deemed related to the index procedure

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 6 cited references ↓

01What separates 27050 from 27040 or 27041?

27050 requires an arthrotomy — the joint capsule of the sacroiliac joint is opened and entered. 27040 and 27041 are soft-tissue biopsies of the pelvis and hip area (superficial and deep, respectively) that do not involve entering a joint space. If the operative note does not confirm joint entry, auditors will recode to the appropriate soft-tissue biopsy code.

02Can 27050 be reported bilaterally?

Yes. Bilateral SI joint arthrotomy with biopsy at the same operative session is reported with modifier 50 on a single claim line. Medicare reimburses bilateral procedures at 150% of the single-procedure allowable. Document symmetric disease or independent clinical indication for each side.

03Is prior authorization typically required for 27050?

Most commercial payers and Medicare Advantage plans require prior authorization for open joint surgery. Payers commonly want documentation that imaging-guided needle biopsy was considered or attempted. Check individual plan requirements before scheduling; absence of auth is a top reason for non-clinical denials on this code.

04How does the 90-day global period affect follow-up billing?

All routine post-op visits through day 90 are bundled into the global package — you cannot bill a separate E/M for wound checks, stitch removal, or standard recovery visits. For an E/M addressing a condition unrelated to the SI joint biopsy, append modifier 24 and document the distinct medical issue clearly in the note.

05Can 27050 be reported with a same-session SI joint injection code?

Reporting 27050 with G0259 or G0260 on the same date triggers a bundling edit. If the injection and biopsy were genuinely distinct procedures on separate joint spaces or with separate clinical intent, append modifier 59 to the injection code and document the independent indication. Without that documentation, the injection will deny.

06What ICD-10 diagnoses support medical necessity for 27050?

Common supporting diagnoses include sacroiliitis (M46.1), infectious arthritis of the SI joint (M00.x, M01.x), seronegative spondyloarthropathy (M45.x, M46.x), and neoplasm workup codes when malignancy involves the sacrum or ilium. The diagnosis must align with the clinical rationale for open biopsy versus image-guided needle sampling.

Sources & references

Editorial content was developed using the following public sources. Last verified May 8, 2026.

Mira Scribe

Mira's AI scribe captures the approach to the sacroiliac joint by name, confirms documentation of capsular entry (distinguishing arthrotomy from percutaneous access), records specimen description and laterality, and flags whether prior less invasive biopsy attempts are noted in the record. This prevents downcoding to soft-tissue biopsy codes and blocks medical-necessity denials that arise when the operative note omits the rationale for open surgical access.

See how Mira captures CPT 27050 documentation