Arthroscopy · Knee

Diagnostic arthroscopy of the knee, with or without synovial biopsy — a separate procedure designation meaning it bundles into any same-session surgical knee arthroscopy.

Verified May 8, 2026 · 7 sources ↓

Medicare: $602.89
Total RVUs: 18.05
Global, days: 90
Region: Knee

Drawn from AAPCPriorityhealthCMS

Documentation requirements

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

Source · Editorial brief grounded in 7 cited references ↓

Indications for diagnostic arthroscopy — document why imaging or clinical exam was insufficient and why scope visualization was medically necessary
Operative note must name each compartment entered and describe findings (e.g., medial, lateral, patellofemoral) — generic 'standard approach' language flags audits
If synovial biopsy was taken, document which tissue was sampled, number of specimens, and submission to pathology
Confirm no surgical intervention was performed — absence of surgical findings or decision not to intervene must be explicit to support standalone 29870 billing
Laterality must be documented (left vs. right knee) to support LT/RT modifier use
Pre-procedure conservative treatment history supporting medical necessity, including failed imaging workup or inconclusive MRI findings

Applicable modifiers

Modifiers commonly billed with this code.

Source · AMA CPT modifier descriptors · CMS NCCI Policy Manual

22 Increased complexity 50 Bilateral procedure 51 Multiple procedures 58 Staged or related 59 Distinct service 76 Repeat, same physician 77 Repeat, another physician 78 Unplanned return — related 79 Unrelated during global LT Left side RT Right side

What this code covers

Source · Editorial summary grounded in 7 cited references ↓

CPT 29870 covers knee arthroscopy performed solely for diagnostic evaluation, allowing direct visualization of intra-articular structures including cartilage, menisci, ligaments, and the synovial lining. When clinical findings warrant it, a synovial tissue sample may be taken during the same scope entry for pathologic analysis — that biopsy does not change the code or trigger an add-on.

The 'separate procedure' designation on 29870 is the critical billing rule. Any same-session surgical knee arthroscopy — 29871 through 29887 — bundles 29870 into it. You cannot unbundle with modifier 59 or XS. If the surgeon goes in diagnostically and finds nothing requiring surgery, 29870 stands alone. The moment a surgical arthroscopy code applies, 29870 disappears from the claim.

The 90-day global period applies. Post-op visits within that window are included unless a new, unrelated problem is addressed — in which case modifier 24 is required on the E/M. If the same surgeon performs an unrelated knee procedure during the global (e.g., a contralateral knee procedure), modifier 79 applies. A planned staged procedure on the same knee within the global uses modifier 58.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	5.06
Practice expense RVU	11.96
Malpractice RVU	1.03
Total RVU	18.05
Medicare national rate	$602.89
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	$602.89
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 29870 get rejected.

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

Bundling denial when billed alongside a surgical knee arthroscopy code on the same knee same session — 29870 is always included in surgical arthroscopies
Medical necessity denial for osteoarthritic knee presentations — CMS LCD guidance restricts diagnostic arthroscopy when OA is the primary diagnosis without a distinct non-OA pathology being evaluated
Missing or inadequate laterality documentation leading to claim rejection or edit
Lack of documented failed conservative or imaging workup prior to proceeding with diagnostic scope
Incorrect global period billing — E/M visits during the 90-day post-op window denied without modifier 24 when the visit is unrelated to the original procedure

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 7 cited references ↓

01Can I bill 29870 alongside a surgical knee arthroscopy code on the same knee?

No. 29870 is a 'separate procedure' and is always bundled into any surgical knee arthroscopy performed in the same session on the same knee. Modifier 59 does not override this — it is an NCCI component edit. Drop 29870 from the claim and bill the surgical code only.

02Does taking a synovial biopsy during the diagnostic scope change the code?

No. The 'with or without synovial biopsy' language is built into 29870. The biopsy does not elevate the code, require an add-on, or change reimbursement. Document the specimen submission, but keep 29870 as the only arthroscopy code.

03Is 29870 covered by Medicare for an osteoarthritic knee?

Coverage is restricted. CMS has an NCA and supporting LCD articles addressing arthroscopy for osteoarthritic knees. Diagnostic arthroscopy with a primary OA diagnosis is at high risk of non-coverage. Medical necessity must be tied to a distinct, non-OA pathology being evaluated. Review your MAC's LCD before billing.

04Which modifier do I use if the surgeon returns to the OR during the 90-day global for a related knee procedure?

Use modifier 78 — unplanned return to the OR for a related procedure during the global period. Do not use modifier 79, which is reserved for unrelated procedures. Inverting these is a common error that can trigger post-payment audits.

05How does ASC versus HOPD site of service affect 29870 reimbursement?

The HOPD and ASC payment rates differ significantly — see the Site of Service comparison on this page. The physician's professional fee is the same regardless of site; the facility fee is what changes. For procedures that can be safely performed in an ASC, the ASC setting typically results in lower total episode cost, which some payers factor into authorization decisions.

06Can 29870 be billed bilaterally in the same session?

Yes, if both knees were scoped diagnostically in the same operative session with no concurrent surgical arthroscopy on either side. Use modifier 50 for bilateral billing or LT/RT on separate line items per payer preference. Document separate operative findings for each knee.

Sources & references

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

Mira AI Scribe

Mira's AI scribe captures the compartments visualized, specific intra-articular findings by compartment, whether synovial biopsy was taken and submitted to pathology, laterality, and the explicit statement that no surgical intervention was performed. This prevents the two most common 29870 audit flags: operative notes that fail to justify standalone diagnostic billing and bundling errors when a surgical code should have been the primary code instead.

See how Mira captures CPT 29870 documentation