CPT® Code 29884

Quick Reference: CPT 29884

• Definition: Arthroscopy, knee, surgical; with lysis of adhesions, with or without manipulation (separate procedure).
• Separate Procedure Rule: Cannot be billed with any other arthroscopic knee procedure in the same knee, for both Medicare and non-Medicare claims.
• Global Period: 90 days (major surgical package). All routine follow-up visits are bundled.
• Work RVUs: Approximately 8.28 (subject to the 2026 CMS 2.5% efficiency adjustment for surgical procedures).
• 2026 CMS Conversion Factor: $33.57 (APM participants) / $33.40 (non-APM).
• Primary Indication: Fibrous adhesions causing restricted knee range of motion unresponsive to conservative care, often following prior knee surgery or trauma.
• Key Laterality Modifiers: RT (right) or LT (left) required for accurate claim submission.

CPT 29884 — Arthroscopy, knee, surgical; with lysis of adhesions, with or without manipulation (separate procedure) — is a surgical arthroscopy code used when a surgeon arthroscopically removes fibrous bands of scar tissue (adhesions) from inside the knee joint to restore range of motion and reduce pain.

The designation “separate procedure” in the code descriptor is one of the most consequential and frequently misunderstood features of this code: it creates a blanket restriction against billing 29884 alongside any other knee arthroscopic procedure performed in the same operative session, regardless of payer. Coders who do not recognize this restriction risk claim denials, audit exposure, and potential recoupment.

This guide walks you through every critical facet of 29884 billing — from operative documentation and NCCI edits to ICD-10 pairings, global period rules, and 2026-specific reimbursement updates.

1. Procedure Definition & Clinical Overview

CPT 29884 describes a minimally invasive surgical arthroscopic procedure performed on the knee joint with the specific intent of lysing — cutting, separating, and removing — fibrous adhesions (scar tissue bands) that are restricting joint motion or causing pain. The code descriptor explicitly allows for manipulation of the joint (forceful movement under anesthesia to break up adhesions) to occur as part of the same surgical session, with or without it being performed.

What Happens Intraoperatively

The surgeon begins with a standard knee arthroscopy setup: the patient is placed supine on the operating table, a tourniquet is applied, and small portal incisions are made around the knee. The arthroscope — a thin, lighted camera — is introduced into the joint space via an anterolateral or anteromedial portal. The surgeon systematically surveys all three knee compartments (medial, lateral, and patellofemoral) to identify fibrous adhesive bands. Using shavers, electrocautery probes, or mechanical scissors introduced through a working portal, the surgeon carefully resects and ablates adhesions. If the patient has severe stiffness (arthrofibrosis), the surgeon may perform manipulation under anesthesia (MUA) — applying controlled force to the joint — either before or after arthroscopic lysis to maximize the range-of-motion gained. Small portal incisions are then closed, and a sterile dressing is applied. The procedure typically takes 30 to 60 minutes.

Clinical Indications

29884 is appropriate when the following conditions exist and conservative treatment has been exhausted:

• Arthrofibrosis of the knee following prior arthroscopic or open surgery (e.g., ACL reconstruction, total knee arthroplasty).
• Cyclops lesion — a specific form of post-ACL reconstruction fibrosis causing a loss of terminal extension.
• Post-traumatic knee stiffness with documented fibrous adhesion formation on MRI or diagnostic arthroscopy.
• Stiffness of the knee (M24.661–M24.662) unresponsive to at least 6–12 weeks of supervised physical therapy.
• Restricted range of motion following immobilization or casting, with confirmed adhesive pathology.

2. The “Separate Procedure” Rule — The #1 Billing Trap

The most critical coding rule for 29884 is embedded directly in its official CPT descriptor: “(separate procedure).” Per AMA CPT guidelines, when a procedure is designated as a “separate procedure,” it is considered integral to and included within any other more comprehensive procedure performed at the same anatomic site during the same operative session. In plain terms: you cannot bill 29884 alongside any other knee arthroscopy procedure.

Universal “Separate Procedure” Restriction: For both Medicare and non-Medicare claims, CPT 29884 (arthroscopic lysis of adhesions) should not be reported with any other arthroscopic knee procedure performed in the same knee at the same session. This rule holds whether the second procedure involves meniscectomy (29880/29881), lateral release (29873), synovectomy (29875/29876), chondroplasty (29877), or any other code in the 29870–29889 family. Reporting both codes without meeting strict criteria for distinct, separate procedures will result in automatic claim denial or payer recoupment upon audit.

The Only Exception: Truly Distinct Procedures in Different Sessions or Joints

The “separate procedure” restriction applies to the same knee in the same operative session. If the patient requires a separate surgery on the contralateral knee, 29884 may be reported independently for that joint using the appropriate laterality modifier (LT or RT). Additionally, if two truly separate surgeries occur on different dates of service, 29884 may be independently billable.

flowchart TD
    A["Lysis of adhesions\nperformed arthroscopically"] --> B{"Was any OTHER\narthroscopic procedure\nperformed in the SAME knee?"}
    B -->|Yes| C["Do NOT bill 29884\nAdhesion lysis is bundled\ninto the other procedure"]
    B -->|No| D{"Is lysis the PRIMARY\nsurgical objective?"}
    D -->|Yes| E{"Within global period\nof prior knee surgery?"}
    D -->|No| F["Do NOT bill 29884\nIncidental lysis is not\nseparately reportable"]
    E -->|Yes| G{"Was this procedure\nplanned or unplanned?"}
    E -->|No| H["Bill 29884 + RT/LT"]
    G -->|Planned or staged| I["Bill 29884-58 + RT/LT"]
    G -->|Unplanned complication| J["Bill 29884-78 + RT/LT"]

    style C fill:#f8d7da,stroke:#721c24
    style F fill:#f8d7da,stroke:#721c24
    style H fill:#d4edda,stroke:#155724
    style I fill:#d4edda,stroke:#155724
    style J fill:#fff3cd,stroke:#856404

3. NCCI Bundling Edits & CCI Conflicts

The Centers for Medicare & Medicaid Services (CMS) enforces 29884’s “separate procedure” designation through the National Correct Coding Initiative (NCCI) — also called CCI edits. NCCI edits bundle 29884 into several more comprehensive knee arthroscopy codes, including:

• 29873 (Knee arthroscopy with lateral release): CCI bundles 29884, 29874, 29875, and 29877 into 29873. If lateral release is performed, lysis of adhesions is considered included and not separately reportable.
• 29880/29881 (Meniscectomy, medial and/or lateral): Because meniscal excision necessarily involves clearing the operative field — which may include adhesive tissue — lysis of adhesions is bundled.
• 29882/29883 (Meniscus repair): Similarly bundled when meniscus repair is the primary procedure.

How to Check CCI Edits Before Submitting

Before submitting any claim pairing 29884 with another knee arthroscopy code, verify the combination using the CMS NCCI edit lookup tool. This tool is updated quarterly and reflects the most current bundling rules. Even when two codes technically have an “indicator 1” (modifier allowed), the clinical documentation must affirmatively support that both were performed at distinct operative steps and that the lysis of adhesions was clinically necessary as a standalone intervention — not merely incidental to another procedure.

The Multiple-Scope Rule (Medicare)

Medicare’s “multiple endoscopy rule” applies across the 29870–29889 knee arthroscopy family. Under this rule, Medicare pays the full fee schedule amount only for the highest-valued procedure in the family and pays any additional procedures at a reduced rate (the second code’s value minus the base code’s value). However, because 29884 is a “separate procedure,” it is effectively excluded from billing alongside other codes in this family regardless of the multiple-scope rule framework.

4. Audit-Proof Operative Documentation Standards

Because 29884 is a “separate procedure” with a high potential for denial, the operative report must be crystal clear that lysis of adhesions was the primary — and only — arthroscopic surgical procedure performed in that knee during the session. Vague documentation is the fastest path to a post-payment audit and recoupment.

Essential Elements of the Operative Report

• Pre-operative Diagnosis: Must reflect a diagnosis consistent with fibrous adhesive pathology (e.g., “Arthrofibrosis, right knee, status post ACL reconstruction, with restricted terminal extension secondary to cyclops lesion”). Use specific ICD-10 codes that map to scar tissue or stiffness — not generic “knee pain.”
• Conservative Treatment Failure: Document that the patient failed at least 6–12 weeks of formal, supervised physical therapy, NSAIDs, and/or corticosteroid injections. Payers require documented failure of conservative management before approving arthroscopic lysis of adhesions. Attach physical therapy records or office notes to the prior authorization request.
• Intraoperative Findings: Describe exactly what the surgeon found — e.g., “Dense fibrous adhesive bands noted in the medial gutter and suprapatellar pouch, restricting patellar excursion and tibial rotation. A cyclops lesion measuring approximately 1.5 cm was identified at the ACL graft insertion site.” Vague findings like “scar tissue present” are insufficient.
• Procedure Description: Detail the tools used and the specific adhesive bands addressed. For example: “Using an arthroscopic shaver and electrocautery probe, fibrous adhesive bands in the medial gutter, suprapatellar pouch, and intercondylar notch were systematically resected. The cyclops lesion was excised in its entirety. Manipulation of the knee was performed, achieving 0–130 degrees of flexion postoperatively, compared to 0–85 degrees preoperatively.”
• Laterality: Clearly document which knee (right or left) was treated. This maps to your laterality modifier (RT or LT).
• No Other Procedures Performed: If 29884 is the only arthroscopic code billed, the operative report should confirm no other surgical procedures were performed in the same knee. Explicitly state “no other arthroscopic surgical intervention was performed.”
• Range of Motion Pre vs. Post: Document the measurable improvement in range of motion achieved. This is strong evidence of medical necessity and clinical effect.

What NOT to Write (Audit Red Flags)

• Avoid generic phrases like “scar tissue removed” without anatomic detail.
• Do not use copy-paste boilerplate operative reports — payers and RAC auditors flag these.
• Do not document both a meniscectomy and lysis of adhesions in the same report unless they occurred in truly separate operative sessions — doing so invites unbundling accusations.
• Avoid implying lysis of adhesions was simply “incidental” to viewing the knee — it must be the primary surgical objective if 29884 is billed alone.

5. ICD-10 Diagnosis Codes & Medical Necessity

Choosing the correct ICD-10 code is the foundation of medical necessity for 29884. Payers cross-reference the diagnosis code against the procedure to determine whether the intervention was clinically justified. Generic or unspecific codes are a primary cause of prior authorization denial and claims rejection.

Clinical Note: For the strongest medical necessity justification, always code the most specific diagnosis first — the one that most directly explains why the lysis of adhesions is necessary (typically M24.661 or M24.662). Follow with secondary codes that explain the etiology (e.g., Z96.651 for post-TKA status, Z98.89 for post-surgical state).

6. Medicare Coverage, Reimbursement & 2026 Fee Schedule

2026 Medicare Physician Fee Schedule (MPFS) Updates

The 2026 Medicare Physician Fee Schedule Final Rule (CMS-1832-F) introduced two significant changes that directly affect reimbursement for CPT 29884:

• Efficiency Adjustment (–2.5%): CMS finalized a 2.5% reduction to work RVUs for nearly all non-time-based services, including surgical procedures. CPT 29884’s previously established work RVU of approximately 8.28 is subject to this reduction in 2026. Practices should adjust their compensation models and revenue projections accordingly.
• Conversion Factor Increase: For the first time in several years, the Medicare conversion factor increased. The 2026 conversion factors are: $33.57 for qualifying APM participants (a 3.77% increase from 2025’s $32.35) and $33.40 for non-APM participants (a 3.26% increase). The net reimbursement impact for surgical procedure codes like 29884 is effectively reduced when the RVU efficiency cut is factored against the conversion factor gain.
• Facility vs. Non-Facility PE RVU Changes: CMS also modified indirect practice expense (PE) RVU calculations for facility-based services. Because most knee arthroscopies are performed in a hospital outpatient department (HOPD) or ambulatory surgical center (ASC) — both considered facility settings — reimbursement for 29884 in facility settings may be lower than in prior years. Non-facility (office-based) settings are less affected.

Place of Service (POS) Codes

• POS 22 (Outpatient Hospital): Most common for 29884. Use when the procedure is performed in a hospital-based outpatient surgical suite.
• POS 24 (Ambulatory Surgical Center): Used when the procedure is performed in an independently certified ASC. ASC reimbursement follows a separate CMS ASC payment system rather than the MPFS.
• POS 11 (Office): Rarely applicable; knee arthroscopy is almost never performed in a physician’s office. Use of POS 11 for a surgical arthroscopy would be a significant billing red flag.

Medicare Medical Necessity Requirements

Medicare generally covers 29884 when the following criteria are documented:

• The patient has clinically significant restriction of knee range of motion (e.g., flexion limited to less than 90°, or an extension lag greater than 10°).
• Conservative treatment — including physical therapy, anti-inflammatory medications, and/or corticosteroid injections — has been tried and failed for a minimum of 6–12 weeks.
• Imaging (MRI or prior arthroscopy report) has confirmed the presence of fibrous adhesive bands within the knee joint.
• The restriction is not explained by bony pathology, prosthetic malposition, or another structural abnormality that would require a different surgical approach.

Medicare Advantage (MA) Plans: Coverage criteria for 29884 under Medicare Advantage plans may differ from traditional Medicare. Many MA plans (including Humana and BCBS MA plans) require prior authorization for all knee arthroscopic procedures, including lysis of adhesions, and apply stricter criteria for conservative treatment failure documentation. Always verify the specific plan’s prior authorization requirements before scheduling the procedure.

7. Modifier Usage

Laterality Modifiers: RT and LT (Required)

CPT 29884 must always include a laterality modifier indicating which knee was treated:

• RT: Right knee (e.g., 29884-RT)
• LT: Left knee (e.g., 29884-LT)

Submitting 29884 without a laterality modifier is a common cause of rejection and is required by Medicare and most commercial payers.

Modifier 22 (Increased Procedural Services)

Append modifier 22 when the procedure was substantially more complex than typically required — for example, when the surgeon encountered unusually dense, pan-compartmental adhesions requiring extensive operative time and effort beyond the standard lysis procedure. Documentation must support the additional complexity with a detailed operative note describing the extent and challenge of the adhesions, the total operative time, and a separate written justification explaining why modifier 22 is appropriate. Reimbursement with modifier 22 typically results in a 20–30% payment increase, though payers may audit these claims closely.

Modifier 58 (Staged or Related Procedure During Global Period)

Use modifier 58 when 29884 is performed during the postoperative global period of a prior knee surgery and the lysis procedure was either: (1) planned prospectively as a staged intervention, (2) more extensive than the original surgery, or (3) a therapeutic intervention for a condition arising from the prior surgery. For example, if an ACL reconstruction (29888) was performed 3 months ago and the patient now requires arthroscopic lysis of adhesions for arthrofibrosis, report 29884-58. This signals to the payer that the procedure was related to the prior surgery but is separately billable.

Modifier 78 (Unplanned Return to OR for Related Complication)

Modifier 78 applies when a patient returns to the operating room during the global period of a prior surgery for treatment of a complication of that surgery. If adhesions develop as a direct complication of a prior arthroscopic procedure and require a return to the OR for lysis — and the return was unplanned — report 29884-78. Unlike modifier 58, modifier 78 typically results in a reduced payment (only the intraoperative components are reimbursed; pre- and post-op care remain in the global package of the prior procedure).

Modifier 24 (Unrelated E/M Service During Global Period)

This modifier applies to the evaluation and management visit, not to 29884 itself. If, during the 90-day global period of 29884, the surgeon evaluates the patient for a completely unrelated medical condition (e.g., a new shoulder injury), the E/M service may be billed with modifier 24 appended to the E/M code.

Modifier 59 (Distinct Procedural Service)

Do not use modifier 59 to override the “separate procedure” bundling restriction for 29884 with other knee arthroscopy codes performed in the same operative session. As explained by AAPC and reinforced through NCCI guidelines, the “separate procedure” designation for 29884 is not overridable with modifier 59 when another comprehensive arthroscopic procedure is performed in the same knee. Attempting to use modifier 59 in this context is considered unbundling and is a compliance risk.

8. 90-Day Global Period Rules

CPT 29884 carries a 90-day global surgical period, which means Medicare and most payers bundle all routine pre-operative and post-operative care into the single surgical payment for 90 days following the procedure.

What Is Included in the Global Package

• Pre-operative care: E/M visits beginning the day before the procedure through the day of surgery (when the decision for surgery has already been made).
• Intraoperative services: The procedure itself, anesthesia care coordination, and any intraoperative complications managed without a return to the OR.
• Post-operative care (90 days): All routine follow-up visits, suture removal, wound checks, range-of-motion assessments, and standard complication management included within the global package.
• Physical therapy referrals and prescriptions: Writing a PT referral during the global period is bundled; however, the PT provider may bill independently for their services.

What Is NOT Included (Separately Billable)

• Treatment of a new, unrelated injury or condition during the global period (use modifier 24 on the E/M code).
• A return to the OR for a complication requiring additional surgery (use modifier 78 or 58 as appropriate).
• Diagnostic imaging ordered for a new clinical issue (e.g., MRI for suspected new meniscal tear after the patient re-injures the knee).
• Care provided by a different specialty for a completely unrelated condition.

CPT 99024 — Post-Op Reporting for Data Collection: CMS requires that physicians in mandatory reporting states submit CPT code 99024 (Postoperative follow-up visit, normally included in the surgical package; no charge) for post-operative visits that occur within the 90-day global period. While 99024 carries $0 reimbursement, CMS uses this data to evaluate whether global surgery values accurately reflect actual post-operative care. Failure to report 99024 in required states may attract CMS attention during audits.

9. Code Comparison: Related Knee Arthroscopy Codes

10. Prior Authorization Requirements by Major Payer

Prior authorization (PA) for CPT 29884 is increasingly required by commercial and Medicare Advantage payers. Submission without a required PA is the most common cause of initial denial.

• Humana (Commercial & Medicare Advantage): Humana’s Hip, Knee, and Shoulder Arthroscopic Surgeries policy requires prior authorization for all arthroscopic knee procedures, including 29884. The PA request must include documentation of restricted ROM, failed conservative treatment (≥6 weeks PT), and imaging confirming adhesive pathology.
• CIGNA/Evernorth: Under CIGNA’s Site of Care policy for outpatient musculoskeletal procedures (Policy 0553), prior authorization may be required when 29884 is performed in a hospital outpatient setting. ASC is preferred; PA may be waived in ASC settings per policy.
• UnitedHealthcare (UHC): UHC requires prior authorization for knee arthroscopic procedures through its UnitedHealthcare Medical Policy for musculoskeletal procedures. Submit clinical notes, PT records, and operative plan details via the UHC Provider Portal.
• Point32Health (Tufts/Harvard Pilgrim): HKSS Prior Authorization policy applies; submit via the prior authorization portal with clinical supporting documentation.
• Traditional Medicare (Parts A & B): No prior authorization is required for 29884 under Traditional Medicare Fee-for-Service. However, documentation must support medical necessity in the event of a Targeted Probe and Educate (TPE) or Recovery Audit (RAC) review.
• Medicaid: PA requirements vary by state Medicaid program. Many states require PA for elective arthroscopic procedures. Verify with the specific state MAC or managed Medicaid contractor.

11. Complex Clinical Scenarios

Scenario 1: Post-ACL Reconstruction Arthrofibrosis with Cyclops Lesion

Patient: 28-year-old male, 4 months post right knee ACL reconstruction (29888), presenting with loss of terminal extension (extension lag of 15°) and moderate anterior knee pain. MRI shows a nodular soft tissue mass in the anterior intercondylar notch consistent with a cyclops lesion.

Conservative Treatment: Patient completed 12 weeks of formal physical therapy with no improvement in extension.

Procedure: Arthroscopic lysis of adhesions, right knee, with resection of cyclops lesion. Manipulation under anesthesia performed. Terminal extension restored to 0°.

ICD-10: M24.661 (Stiffness, right knee), Z98.89 (Post-surgical state post ACL reconstruction).

Coding: 29884-RT. Rationale: The cyclops lesion is the classic arthrofibrosis complication of ACL reconstruction. 29884 is the correct code for arthroscopic lysis of this adhesive scar tissue. Because this is performed during the 90-day global period of 29888, append modifier 58 (staged/related procedure). Payer must be notified that this is a related post-surgical complication requiring planned secondary intervention.

Scenario 2: Post-Total Knee Arthroplasty Stiffness

Patient: 68-year-old female, 5 months post left total knee arthroplasty (TKA), with persistent knee stiffness. Flexion limited to 75° despite 16 weeks of intensive physical therapy. Fluoroscopy confirms appropriate prosthesis position. MRI indicates significant fibrous pannus formation and peri-prosthetic adhesions.

Procedure: Arthroscopic lysis of adhesions, left knee. Manipulation under anesthesia performed intraoperatively. Flexion improved to 115°.

ICD-10: M24.662 (Stiffness, left knee), T84.84XD (Pain due to internal orthopedic prosthetic device, subsequent encounter), Z96.652 (Presence of left artificial knee joint).

Coding: 29884-LT. Rationale: Post-TKA arthrofibrosis is a well-recognized indication for 29884. The TKA itself is outside the 90-day global period (5 months post-op), so no modifier for global period is needed here. Prior authorization is critical for Medicare Advantage plans — submit with PT records, flexion measurements, and imaging.

Scenario 3: Surgeon Attempts to Bill 29884 with 29881 — Denial Scenario

Patient: 45-year-old with medial meniscus tear and pre-existing scar tissue from a prior partial meniscectomy 2 years ago.

Procedure Performed: Arthroscopic medial meniscectomy (29881) and incidental lysis of adhesive bands encountered in the medial compartment.

Incorrect Coding: 29881-RT + 29884-59-RT. Why this is wrong: 29884 is a “separate procedure.” Incidental lysis of adhesions encountered during a meniscectomy is integral to the meniscectomy. Modifier 59 cannot override the “separate procedure” restriction when another arthroscopic procedure is being performed. This submission constitutes unbundling and will be denied or recouped on audit.

Correct Coding: 29881-RT only. Rationale: If the adhesions are the dominant pathology requiring the primary surgical objective — and the meniscal pathology is minor or incidental — then the surgeon should instead report 29884 only (not 29881). The documentation must support which condition was the primary surgical target.

Scenario 4: Bilateral Knee Lysis of Adhesions (Different Dates)

Patient: 55-year-old with bilateral knee arthrofibrosis following bilateral TKA performed 6 months ago.

Procedure: Lysis of adhesions performed on right knee (Day 1), followed by lysis of adhesions on left knee (Day 14, after right knee recovery).

Coding (Day 1): 29884-RT. Coding (Day 14): 29884-LT.

Rationale: When procedures are performed on separate dates of service on opposite knees, each 29884 is independently billable with the appropriate laterality modifier. The 90-day global period from Day 1 (29884-RT) does not restrict billing of the left knee procedure on Day 14, because the procedures involve different anatomic sites (different joints).