Arthroscopy · Knee

Knee arthroscopy with abrasion arthroplasty — including chondroplasty where necessary — or multiple drilling or microfracture of articular cartilage.

Verified May 8, 2026 · 7 sources ↓

Medicare: $623.26
Total RVUs: 18.66
Global, days: 90
Region: Knee

Drawn from CMSPriorityhealthAAPCNIHAAOS

Documentation requirements

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

Source · Editorial brief grounded in 7 cited references ↓

Specify laterality — left, right, or bilateral — in the operative note and on the claim
Identify the exact compartment(s) treated (medial, lateral, patellofemoral) to support separate reporting of multiple procedures
Document the technique used: abrasion arthroplasty, multiple drilling, or microfracture — do not use generic terms
Describe the size and location of the chondral defect, including depth and condition of surrounding cartilage
Record conservative treatment tried and failed to establish medical necessity for cartilage intervention
If chondroplasty was also performed, document it as incidental and included under 29879 — do not list it as a separate procedure

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 59 Distinct service 76 Repeat, same physician 77 Repeat, another physician 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 7 cited references ↓

CPT 29879 covers arthroscopic knee surgery focused on cartilage repair through abrasion arthroplasty, multiple drilling, or microfracture techniques. The code explicitly includes chondroplasty when performed as part of the same procedure. These techniques are used to stimulate fibrocartilage formation in areas of full-thickness chondral defects. The 90-day global period means all routine follow-up care, wound checks, and postoperative visits through day 90 are bundled — bill with modifier 24 or 79 only for genuinely unrelated services in that window.

Bundling is the central billing risk here. Chondroplasty (29877) is never separately reportable with 29879 — it is explicitly included. More critically, if a meniscectomy (29880 or 29881) is performed in the same compartment, any chondroplasty or shaving in that compartment is considered part of the meniscectomy's global service; 29879 cannot be added. Codes 29874, 29877, 29879, and 29885–29887 cannot be reported together when the surgical work occurs within the same compartment. Distinct-compartment work requires modifier 59 or XS with supporting documentation naming each compartment.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	8.77
Practice expense RVU	8.07
Malpractice RVU	1.82
Total RVU	18.66
Medicare national rate	$623.26
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	$623.26
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 29879 get rejected.

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

29877 billed alongside 29879 — chondroplasty is already included in the code descriptor and will be bundled
29879 billed with 29880 or 29881 when the chondroplasty and meniscectomy are in the same compartment — the shaving is considered part of the meniscectomy global
Missing laterality modifier (LT or RT) required by many payers for unilateral knee procedures
Lack of documented chondral defect severity or failed conservative care undermining medical necessity
Same-compartment procedures billed without modifier 59 or XS, triggering NCCI PTP bundling edits

Frequently asked questions

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

01Can 29879 and 29877 be billed together?

No. Chondroplasty (29877) is explicitly included in the 29879 descriptor. Billing both will result in 29877 being bundled and denied. Do not attempt a modifier override — this is an inclusive edit, not a modifier-bypassable PTP pair.

02Can 29879 be billed with 29880 or 29881 on the same knee?

Only if the abrasion arthroplasty is in a different compartment from the meniscectomy. When both occur in the same compartment, the chondroplasty or shaving is considered part of the meniscectomy's global service. Separate compartment work requires modifier 59 or XS and operative note documentation naming each compartment.

03Can 29879 be billed with 29876 on the same day?

This is a known gray area. Per AAPC forum discussion, 29876 (major synovectomy, 2+ compartments) and 29879 may require modifier 59 to bypass a PTP edit if billed together. Verify current NCCI PTP tables before submitting, and ensure documentation clearly distinguishes the work performed for each code.

04What ICD-10 diagnoses support 29879?

Full-thickness chondral defects, osteochondral lesions, and osteochondritis dissecans are the primary supporting diagnoses. Codes from the M93 (osteochondropathy) and M94 (other cartilage disorders) families are most relevant. Document defect grade and failed conservative management to clear medical necessity review.

05Does the 90-day global period affect billing for a separate injury during recovery?

Yes. Any service during the 90-day global related to the knee surgery is bundled. For a genuinely unrelated condition or procedure on the same knee, append modifier 79 (unrelated procedure) or modifier 24 (unrelated E/M). Modifier 78 applies only if the patient returns to the OR for a complication related to the original procedure.

06Is 29879 subject to site-of-service payment differences?

Yes. HOPD and ASC payments differ materially — see the site-of-service comparison table on this page. Physician work RVUs are the same regardless of setting, but facility payments and total allowables vary. Most of this volume moves to ASC settings, which affects global budget planning.

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 arthroscopic technique (abrasion arthroplasty, multiple drilling, or microfracture), the specific compartment(s) treated, defect size and depth, and whether chondroplasty was incidental. It also flags when a meniscectomy is performed in the same compartment — the single most common trigger for a 29879 denial — so the coder knows before the claim is submitted rather than after.

See how Mira captures CPT 29879 documentation