CPT code 27415 – Osteochondral allograft implantation, knee

Key takeaways

CPT code 27415 covers open osteochondral allograft implantation in the knee, while arthroscopic grafting is reported with 29866 or 29867.

Prior authorization is required by virtually all payers, and surgery performed without it is the most common denial trigger for this code.

Codes 29870 and 29877 are bundled into 27415 under NCCI edits, so check the current NCCI table before billing either one.

Pabau, the practice management platform we build, flags claims missing an authorization number before they reach the clearinghouse.

CPT code 27415: Definition and clinical description

CPT code 27415 is defined by the American Medical Association as: Osteochondral allograft, knee; open. It sits in the 27380-27499 subsection, Repair, Revision, and/or Reconstruction Procedures on the Femur (Thigh Region) and Knee Joint.

The procedure involves transplanting a fresh osteochondral plug from a cadaveric donor knee into a focal cartilage defect on the recipient’s articular surface.

The key word in the descriptor is open. A surgical arthrotomy is required to reach and prepare the defect site, so a portal-only arthroscopic case never qualifies. “Allograft” means the graft comes from a donor, distinguishing it from autograft procedures where the surgeon harvests tissue from the patient’s own body.

The graft must be fresh, meaning viable chondrocytes are present at the time of implantation. Fresh allografts are transplanted within a narrow viability window, typically 28 to 35 days from procurement.

Frozen or cryopreserved grafts do not meet the clinical definition for this code; payer policies may also distinguish between graft types when assessing coverage. That is why the operative note has to name the graft type.

Before selecting 27415, the coder should confirm two facts from the note: an open approach and donor tissue.

CPT 27415 vs. related knee cartilage codes

The most common coding error with 27415 is reaching for it after an arthroscopic approach. The second is using it when the graft came from the patient rather than a donor. The table below clarifies the key distinctions. Full descriptors for each neighboring code sit in our CPT code reference.

The 27415 vs. 29867 question comes up frequently in audits. If the surgeon performed an arthroscopic allograft transplantation, 29867 is the correct code, not 27415. The approach documented in the operative note settles it. An arthrotomy supports 27415, while portal-only access points to an arthroscopic code.

The grid below reduces the choice to two questions for the note. How did the surgeon reach the defect, and where did the graft come from?

What CPT 27415 includes and excludes

27415 carries a 90-day global surgical period, which means routine follow-up care is bundled. Several arthroscopic knee procedures are also bundled under NCCI edits and cannot be billed separately when performed at the same session.

Bundled codes (cannot bill separately)

• 29870, diagnostic knee arthroscopy, included per NCCI edits
• 29877, knee arthroscopy with chondroplasty, included per NCCI edits
• Routine post-operative visits during the 90-day global period
• Standard wound closure and graft fixation hardware included in the procedure

Separately reportable services

• Significant, separately identifiable E&M services on the same date (requires modifier -25)
• Services unrelated to the operative knee during the global period (modifier -79)
• Treatment of complications arising from the procedure (modifier -78)
• Physical therapy, billed by the therapist rather than the surgeon
• Allograft tissue acquisition cost, typically billed by the facility as a supply line separate from the surgeon’s CPT fee

NCCI edit relationships are updated quarterly by CMS. Bundling status for 29870 and 29877 should be verified against the current CMS Physician Fee Schedule and NCCI table before billing decisions are finalized.

Modifiers for CPT code 27415

Surgical modifiers for 27415 follow standard orthopedic conventions. Missing a laterality modifier is one of the most common causes of claim delay on knee procedures.

Modifier -50 for bilateral knee osteochondral allograft is uncommon given the high cost and tissue availability constraints, but it does occur. Some payers require -50 on a single line; others require two lines with -RT and -LT. Verify the specific payer’s bilateral billing policy before submitting.

ICD-10 diagnosis codes paired with CPT code 27415

The diagnosis codes linked to 27415 must describe a focal, full-thickness articular cartilage defect. Vague or incomplete diagnosis coding is a medical necessity failure that triggers denial regardless of whether the prior authorization was approved.

Osteochondritis dissecans codes (M93.261/M93.262) are the most commonly paired diagnoses for this procedure. When the defect resulted from trauma, S83 series codes (knee dislocation or ligament injury) may also apply as secondary diagnoses to establish the mechanism. Verify the laterality matches the operative site on both the diagnosis code and the CPT modifier.

Medicare and payer reimbursement for CPT 27415

Reimbursement for CPT code 27415 is set annually by the CMS Physician Fee Schedule. Rates vary by geographic location through the Geographic Practice Cost Index (GPCI) adjustment. A national average is only a starting point for any one practice.

For 2026, the approximate Medicare non-facility payment for 27415 falls between $1,100 and $1,400, depending on locality. The figure combines the published work RVU, practice expense, and malpractice components.

Use the FastRVU 2026 RVU lookup tool to calculate the exact payment for your Medicare Administrative Contractor (MAC) jurisdiction. Always verify figures against the current year’s published fee schedule before quoting or budgeting.

An important distinction for facility billing: the allograft tissue acquisition cost is not bundled into the surgeon’s CPT fee. The facility typically bills the graft as a separate supply or implant line item. Some payers bundle the graft cost into the facility payment; others allow pass-through billing. Verify payer-specific rules before processing the facility claim.

Commercial payer rates vary widely and typically exceed Medicare rates. Post each remittance against the contracted rate for that carrier, since a short payment on a case this size is costly to overlook.

Prior authorization requirements for CPT 27415

Virtually all commercial payers and Medicare Advantage plans require prior authorization for CPT 27415 given the high cost of fresh allograft tissue. Missing or expired authorization before surgery is the single most common reason claims are denied outright. Retroactive authorization is rarely granted.

Run insurance eligibility verification and start the prior authorization process as soon as the surgical date is confirmed.

Typical documentation required for prior authorization

• MRI of the affected knee: confirming defect location, size (in cm²), and depth (full-thickness)
• Failed conservative treatment documentation: typically 3 to 6 months of physical therapy, activity modification, or less invasive intervention
• Surgeon’s letter of medical necessity: stating why osteochondral allograft is appropriate versus less extensive cartilage procedures
• Patient age and activity level: many payers restrict coverage to patients under 50 or to active patients who have failed prior arthroscopic procedures
• Operative planning notes: defect size and planned graft dimensions

Coverage policies also separate graft types. BCBS Mississippi and BCBS North Dakota, for example, treat fresh osteochondral allograft as potentially medically necessary when their criteria are met. Their policies class processed products, such as decellularized plugs and minced or particulated allograft, as investigational.

Check the payer’s Local Coverage Determination (LCD) or medical policy before scheduling surgery. An investigational classification triggers denial regardless of the prior authorization submission.

Documentation requirements for CPT code 27415

Vague operative notes are the second-leading cause of 27415 denials, after missing prior auth. The operative report must contain enough clinical detail to confirm that the procedure performed matches the code billed. Reviewers look for specific data points, not general descriptions of the surgery. Coders should confirm each element below before the case is closed.

Required elements in the operative note

• Surgical approach: must confirm open arthrotomy (not arthroscopic portals only)
• Defect location: anatomic site: medial femoral condyle, lateral femoral condyle, tibial plateau, or patella
• Defect size: documented in centimeters squared (e.g., “2.5 cm² full-thickness defect”)
• Graft type: must state “fresh osteochondral allograft”; note the procurement date if available
• Graft dimensions: plug diameter and depth
• Fixation method: press-fit, bioabsorbable pins, or screws
• Graft source: tissue bank name or donor reference where applicable
• Post-operative plan: weight-bearing status and rehabilitation protocol

Missing the defect size measurement in cm² is a specific audit trigger. Coders cannot confirm code selection without it, and payer reviewers use it to evaluate whether the allograft approach was clinically justified.

A note that reads “cartilage defect was debrided and allograft was placed” without dimensions does not support CPT code 27415 at audit. Use a clean claim checklist that includes confirming cm² documentation before coding.

Common denial reasons for CPT 27415

Claims for CPT code 27415 are denied more often than many orthopedic codes. High cost, prior authorization rules, and investigational classifications all raise the risk. The most frequent triggers follow a recognizable pattern that good denial management workflows can intercept before submission.

• Missing or expired prior authorization: the most common trigger. Obtain authorization before the operative date and confirm its validity window covers the scheduled surgery date.
• Procedure classified as investigational: some payer policies treat processed allograft products as investigational. Others exclude specific indications, such as age over 50, a previous joint replacement, or certain defect locations.
• ICD-10 code mismatch: a diagnosis code that does not describe a focal full-thickness articular defect fails the payer’s medical necessity crosswalk
• Unbundled arthroscopic codes: billing 29877 or 29870 on the same claim triggers an NCCI edit denial. Verify current bundling status before submitting.
• Graft type not documented as fresh allograft: if the operative note does not say “fresh” allograft, some payers apply frozen or cryopreserved criteria. Those criteria may not meet coverage policy.
• Laterality modifier missing: virtually every knee procedure claim needs -RT or -LT, and its absence triggers automatic payer edits.
• Patient age or defect size outside payer criteria: some payers impose coverage limits, such as a defect larger than 1 cm². Documentation must support the size threshold.

Global period and post-operative billing for CPT 27415

CPT 27415 carries a 90-day global surgical period, meaning CMS assigns it a “090” global period designation. All routine post-operative care from the day of surgery through 90 days is bundled into the procedure payment. The surgeon cannot bill separately for standard follow-up office visits during this window.

What is and is not covered by the global period

The global period also matters when a patient changes providers during recovery. A different physician who treats the patient during the 90-day window bills with modifier -54 or -55 to show the transfer of care. The global payment is then split between them.

How Pabau keeps CPT 27415 claims clean from authorization to payment

A 27415 case passes through several hands before it is paid. The scheduler requests authorization, the coder reads the operative note, and the biller posts the remittance. When each step lives in a separate spreadsheet, an authorization number or a laterality modifier is easy to drop.

Pabau, the practice management platform we build, keeps those steps on one patient record. Its specialty practice claims software runs validation checks that flag a missing authorization code or membership number before submission. US claims go out through the Claim.MD clearinghouse, where your team can also run real-time eligibility checks.

Each claim then moves through tracked stages, from pending to paid, and ERA remittances post against it. Insurer-specific price lists hold each carrier’s rate, so your biller can spot a short payment on a 27415 case the day it lands.

Catch 27415 claim errors before submission

Pabau checks each claim for missing authorization codes and membership details, then tracks it from submission to payment. See how it handles high-value surgical codes like CPT 27415.

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Conclusion

CPT code 27415 rewards practices that settle the coding before the surgery date. Confirm the approach, the graft source, and the authorization while the case is still on the schedule. A claim built that way rarely needs an appeal.

The trade-off is more work up front. Checking every operative note for cm² measurements and fresh-graft wording adds minutes to each case. Those minutes cost far less than reworking a denied claim on one of the highest-value knee procedures you bill.

Book a demo to see how Pabau flags incomplete surgical claims before they reach the payer.

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