Surgical opening of an intertarsal or tarsometatarsal joint with tissue biopsy for diagnostic evaluation

Verified May 8, 2026 · 6 sources ↓

Medicare: $407.16
Work RVU: 4.28
Global, days: 90
Region: Foot & ankle

Drawn from CMSFacsCgsmedicareAAOS

Documentation requirements

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

Source · Editorial brief grounded in 6 cited references ↓

Specify the exact joint entered — intertarsal or tarsometatarsal — by name, not 'midfoot joint'
Document the open approach: incision location, capsulotomy, and exposure technique
Record the indication for biopsy, including clinical findings, imaging results, or suspected diagnosis driving the decision
Confirm tissue specimen was sent to pathology and document the specimen description in the operative note
Note any co-existing procedures performed in the same operative field and their distinct anatomic or clinical justification
If imaging guidance was used intraoperatively, document it separately with its own indication and report

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 51 Multiple procedures 52 Reduced services 58 Staged or related 59 Distinct service 78 Unplanned return — related 79 Unrelated during global 80 Assistant surgeon AS PA/NP/CNS assistant LT Left side RT Right side XS Separate structure

What this code covers

Source · Editorial summary grounded in 6 cited references ↓

CPT 28050 describes an arthrotomy of an intertarsal or tarsometatarsal joint performed specifically to obtain a synovial or tissue biopsy. This is an open procedure — the surgeon incises down to the joint, opens the joint capsule, and excises a specimen for pathologic analysis. It is not an arthroscopic procedure and should not be confused with needle or percutaneous biopsy techniques.

The 90-day global period covers the operative day, the day-before visit, and all routine post-op care through day 90. Any evaluation or procedure in that window for an unrelated problem requires modifier 24 (E/M) or 79 (unrelated procedure). If a complication requires a return to the OR for a related procedure, use modifier 78.

The ACS Assistant at Surgery consensus lists 28050 as 'almost never' requiring a physician assistant. Billing an assistant surgeon (modifier 80 or AS) without documented clinical necessity creates a high-risk audit exposure. If fluoroscopic or other imaging guidance is used intraoperatively and not already bundled into the procedure, check NCCI PTP edits before billing guidance codes separately.

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 (4.28) is the surgeon's own effort — the figure physician pay and productivity targets are built on. The total RVU (12.19) adds practice overhead and malpractice, and is what drives the Medicare payment below.

Work RVU	4.28
Practice expense RVU	7.54
Malpractice RVU	0.37
Total RVU	12.19
Medicare national rate	$407.16
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	$407.16
HOPD (APC 5113) Hospital outpatient department	$3,342.87
ASC (PI A2) Ambulatory surgical center (freestanding)	$1,644.87

Common denial reasons

The recurring reasons claims for CPT 28050 get rejected.

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

Insufficient documentation of medical necessity — payers require clinical rationale (e.g., suspected infection, crystal arthropathy, inflammatory synovitis, or tumor) before authorizing open biopsy over less invasive alternatives
Missing or nonspecific joint identification — operative notes that say 'foot joint' without naming the intertarsal or tarsometatarsal joint are routinely flagged on audit
Incorrect code selection — 28052 (metatarsophalangeal joint) or 28054 (interphalangeal joint) are frequently substituted in error when the anatomy differs; verify joint identity before coding
Global period conflicts — post-op E/M visits billed without modifier 24, or related return procedures billed without modifier 78, deny under the 90-day global
Unbundled imaging guidance billed without modifier support when NCCI PTP edits apply

Frequently asked questions

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

01What is the difference between CPT 28050, 28052, and 28054?

Joint location is the only distinction. 28050 is for intertarsal or tarsometatarsal joints (midfoot). 28052 covers the metatarsophalangeal joint (the ball of the foot). 28054 is for interphalangeal joints (toe joints). Bill the code matching the joint actually entered and biopsied — payers match the code to imaging and operative documentation.

02Can 28050 be billed with an arthroscopy code on the same foot on the same day?

Only if the arthroscopy involves a distinct joint with separate clinical justification. Check NCCI PTP edits for the specific code pair before billing. Modifier 59 or XS may apply, but the medical record must support a genuinely separate service — different anatomic site, different indication, distinct documentation.

03Does the 90-day global period apply to 28050?

Yes. 28050 carries a 90-day global. Routine post-op visits, wound checks, and stitch removal are bundled through day 90. Modifier 24 is required for unrelated E/M visits during the global, and modifier 79 for unrelated procedures. A related return to the OR uses modifier 78.

04Is an assistant surgeon billable for CPT 28050?

The ACS 2023 Assistant at Surgery consensus rates 28050 as 'almost never' needing a physician assistant. Medicare and many commercial payers will deny assistant surgeon claims (modifier 80 or AS) for this code without documented clinical necessity explaining why the complexity required assistance.

05What ICD-10 diagnoses typically support medical necessity for 28050?

Common supporting diagnoses include septic arthritis of a foot joint (M00.87x), crystal arthropathy (gout or CPPD), pigmented villonodular synovitis, inflammatory arthropathy not otherwise characterized, and suspected neoplastic or granulomatous synovial disease. The diagnosis should reflect what required tissue confirmation, not just a symptomatic complaint like foot pain.

06Can 28050 be billed bilaterally?

Bilateral billing would require the same procedure on the same joint type in both feet during one operative session. Use modifier 50 for bilateral submission, or LT/RT on separate lines per payer convention. Clinical scenarios requiring simultaneous bilateral midfoot joint biopsy are uncommon; expect payer scrutiny and ensure documentation explicitly describes both sides.

Sources & references

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

Mira Scribe

Mira's AI scribe captures the joint name (intertarsal vs. tarsometatarsal), the surgical approach and capsulotomy technique, the clinical indication driving the decision to biopsy, and the pathology specimen disposition — all directly from dictation. That prevents the most common audit flag for 28050: an operative note that opens a 'foot joint' without specifying which one, which forces a coder to guess and a payer to deny.

See how Mira captures CPT 28050 documentation