Arthroscopic Lavage and Arthroscopic Debridement for the Osteoarthritic Knee — NCD 285 | CMS Coverage Update

TL;DR: The Centers for Medicare & Medicaid Services modified NCD 285, the national coverage determination governing arthroscopic lavage and arthroscopic debridement for the osteoarthritic knee, effective January 9, 2026. Here's what billing teams need to know.

This CMS arthroscopic knee debridement coverage policy draws a hard line between what Medicare covers and what it doesn't—and the line runs right through your orthopedic surgery claims. NCD 285 in the Medicare system is one of the older national determinations, last clinically reviewed in June 2004, but it remains fully active and fully enforceable. The policy does not list specific CPT codes, which means your code-to-policy mapping depends on your Medicare Administrative Contractor. If your practice bills for arthroscopic knee procedures, this update warrants a careful review of your documentation standards and charge capture workflow.

Quick-Reference Table

CMS Arthroscopic Knee Debridement Coverage Criteria and Medical Necessity Requirements 2026

The CMS arthroscopic lavage and arthroscopic debridement coverage policy under NCD 285 establishes medical necessity based on two factors: disease severity and symptom type. Both have to be right for a claim to hold.

First, the osteoarthritis diagnosis. CMS aligns with the American College of Rheumatology definition. A patient meets the clinical threshold for knee osteoarthritis when they present with knee pain plus at least five of the following: age over 50, morning stiffness lasting fewer than 30 minutes, crepitus on active motion, bony tenderness, bony enlargement, no palpable warmth of the synovium, ESR under 40mm/hr, Rheumatoid Factor under 1:40, or synovial fluid signs.

That's a clinical checklist your documentation needs to support before the procedure happens. If the chart doesn't reflect at least five of those criteria alongside pain, your medical necessity argument starts weak.

Second, severity matters — and CMS uses the Outerbridge classification scale to define it. Grades III and IV represent severe osteoarthritis. Grade III means cartilage fragmentation or fissuring in an area greater than one centimeter. Grade IV means cartilage erosion down to bone. Procedures on patients at these grades are not covered, period.

The coverage window sits at Outerbridge Grades I and II — softening or blistering (Grade I) or fragmentation and fissuring in an area under one centimeter (Grade II). And even within that window, pain alone doesn't justify the procedure. Your documentation has to show mechanical symptoms.

The policy defines mechanical symptoms as locking, snapping, or popping. It also recognizes limb and knee joint alignment issues and early or less severe degenerative arthritis as supporting factors. If the chart only says "knee pain," expect a claim denial.

NCD 285 doesn't specifically call out prior authorization requirements — but your Medicare Administrative Contractor may impose additional documentation requirements before reimbursement. More on that below.

CMS Arthroscopic Knee Procedure Exclusions and Non-Covered Indications

CMS is unusually direct in NCD 285. The policy names three specific scenarios that Medicare will not cover, and it grounds the decision in the absence of scientifically controlled evidence of clinical effectiveness.

The first exclusion: arthroscopic lavage used alone for the osteoarthritic knee. CMS explicitly states that current practice does not recognize any benefit of lavage alone for reducing mechanical symptoms. If your surgeon performs a standalone saline irrigation without debridement, don't bill it expecting Medicare payment.

The second exclusion: arthroscopic debridement for patients who present with knee pain only. This is where billing teams get tripped up. The procedure might be performed. The patient might have a documented osteoarthritis diagnosis. But if the only documented symptom is pain, the claim is non-covered under this policy.

The third exclusion covers the broadest patient population. Arthroscopic debridement and lavage — with or without debridement — is non-covered for any patient presenting with severe osteoarthritis. Severe means Outerbridge Grade III or Grade IV. CMS made this determination after consultation with clinical investigators and the orthopedic community. It's not a gray area.

The real issue here is that surgeons and billing teams aren't always working from the same playbook. The physician documents the procedure. The billing team codes it. If no one catches that the chart shows Grade IV disease with pain-only presentation, that claim goes out and comes back denied. Build the review into your pre-billing workflow, not your appeals workflow.

Coverage Indications at a Glance

CMS Arthroscopic Knee Debridement Billing Guidelines and Action Items 2026

This policy is enforceable as of January 9, 2026. If you haven't already reviewed your workflow against these criteria, do it now.

CPT, HCPCS, and ICD-10 Codes for Arthroscopic Knee Debridement Under NCD 285

Policy Code Coverage Note

NCD 285 does not list specific CPT, HCPCS, or ICD-10 codes in its current published form. This is a known limitation of some older National Coverage Determinations. The absence of codes in the policy document does not mean the policy is inactive — it means code mapping falls to your Medicare Administrative Contractor.

What This Means for Arthroscopic Knee Debridement Billing

Contact your MAC directly to confirm which CPT codes they map to NCD 285 for arthroscopic lavage and debridement procedures. Common arthroscopic knee procedure codes in this clinical category include codes in the 29800 series, but do not assume coverage based on code lookup alone. Your MAC's local coverage determination or billing instructions will govern which codes trigger NCD 285 review.

Request your MAC's claims processing instructions for this NCD. CMS cross-references those instructions directly in the policy, and they may contain code-level specificity that the NCD itself does not include.

ICD-10-CM Diagnosis Codes

NCD 285 does not list specific ICD-10-CM codes. For osteoarthritis of the knee, your coding team should apply the appropriate primary osteoarthritis of knee codes and document severity consistently with the Outerbridge grade captured in the operative note. The diagnosis code alone will not distinguish covered from non-covered claims — the operative and clinical documentation carries the weight.