Arthroscopy · Knee

Arthroscopically assisted treatment of a fracture involving the intercondylar spine and/or tuberosity of the proximal tibia, performed with or without manipulation and with internal or external fixation.

Verified May 8, 2026 · 5 sources ↓

Medicare: $861.74
Total RVUs: 25.8
Global, days: 90
Region: Knee

Drawn from CMSAAPCPriorityhealth

Documentation requirements

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

Source · Editorial brief grounded in 5 cited references ↓

Specify laterality (left or right knee) in both the operative note and on the claim — LT or RT modifier required.
Document the fracture pattern: which structure is involved (intercondylar spine, tibial tuberosity, or both) and displacement status.
Describe the fixation method used — internal (screws, suture anchors) or external — and confirm it was placed during the procedure.
Record whether manipulation was performed prior to or during fixation.
Note the arthroscopic visualization findings, including assessment of associated ligamentous or meniscal injury that was or was not addressed.
Imaging (fluoroscopy or arthroscopic confirmation) of fracture reduction and hardware position should be referenced in the operative note.

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 51 Multiple procedures 58 Staged or related 59 Distinct service 62 Co-surgeons 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 5 cited references ↓

CPT 29851 covers arthroscopically guided fixation of intercondylar spine and/or tuberosity fractures of the knee — the kind of fracture that often involves avulsion of the ACL tibial attachment. The code bundles the arthroscopy itself with the fracture reduction and fixation work; you don't separately bill a diagnostic arthroscopy (29870) alongside it. Internal fixation (screws, suture anchors) and external fixation devices are both captured under this single code. The distinction from 29850 is fixation: 29850 is the without-fixation version; 29851 requires placement of a fixation device.

The 90-day global period starts on the day of surgery. All routine post-op visits, cast or splint management, and hardware-related checks within that window are bundled. If the patient returns for a complication directly tied to the original fixation — hardware failure, loss of reduction — bill modifier 78 (unplanned return to OR, related procedure). For a staged or completely unrelated procedure in the global window, use modifier 79. Any E/M visit during the global for an unrelated problem needs modifier 24.

RVU & reimbursement

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

Source · CMS Physician Fee Schedule, RVU26A · January 2026

Work RVU	12.93
Practice expense RVU	10.12
Malpractice RVU	2.75
Total RVU	25.8
Medicare national rate	$861.74
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	$861.74
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 29851 get rejected.

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

Missing laterality modifier (LT/RT) — payers including Medicare require side identification for unilateral knee procedures.
Diagnostic arthroscopy 29870 billed separately on the same date — it is always bundled into surgical arthroscopy codes and will be denied.
ICD-10 fracture code lacks specificity — unspecified or open/closed designation missing triggers medical necessity edits.
29850 and 29851 billed together for the same knee on the same date — they describe the same fracture site and are mutually exclusive.
Post-op E/M visits billed without modifier 24 during the 90-day global period are automatically denied as included services.

Frequently asked questions

Source · Generated from the editorial pipeline, verified against 5 cited references ↓

01What is the difference between 29850 and 29851?

29850 is arthroscopically assisted treatment of the same fracture without fixation. 29851 requires placement of an internal or external fixation device. If you placed a screw or suture anchor, bill 29851. If you reduced the fracture without hardware, bill 29850. Never bill both for the same knee on the same date.

02Can I bill a diagnostic arthroscopy (29870) with 29851?

No. Diagnostic arthroscopy is always bundled into surgical arthroscopy codes. Billing 29870 alongside 29851 on the same knee will generate an NCCI edit denial. The visualization component is included in 29851 by definition.

03Does 29851 require prior authorization?

Most commercial payers and many Blues plans require authorization for knee arthroscopy with fracture fixation. Some payers route this through musculoskeletal benefit managers (e.g., TurningPoint). Confirm payer-specific requirements before scheduling — authorization requirements are payer-variable, not universal.

04How do I bill if the arthroscopic fracture fixation is converted to open surgery intraoperatively?

If the procedure converts to open, bill only the open tibial fracture fixation code. Per NCCI policy, you cannot report a surgical or diagnostic arthroscopy code alongside the open procedure code when a planned arthroscopic case is converted intraoperatively.

05If the patient returns during the 90-day global for a related complication requiring a return to the OR, what modifier applies?

Use modifier 78 for an unplanned return to the OR for a complication or related condition during the global period. Modifier 79 is for an unrelated procedure in the global window — do not use 78 and 79 interchangeably.

06Can 29851 be billed with other knee arthroscopy codes on the same date?

It depends on what else was done. If associated meniscal or ligamentous pathology was addressed arthroscopically in the same session, those codes may be separately reportable with modifier 59 where NCCI allows. Review the specific code pair in the NCCI edits before billing — blanket use of modifier 59 to bypass bundles is an audit flag.

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 fracture site (intercondylar spine, tibial tuberosity, or both), laterality, displacement status, fixation type and device used, whether manipulation was performed, and the arthroscopic findings including any associated ACL or meniscal pathology documented during the case. Capturing fixation specifics from dictation is what separates a billable 29851 from a downcoded 29850 — missing that one detail is the most common cause of code-level downcoding on audit.

See how Mira captures CPT 29851 documentation