Unicompartmental, Bicompartmental, and Bi-unicompartmental Knee Arthroplasties — CPB 0660 | AETNA Coverage Update

Aetna modified CPB 0660 covering knee arthroplasty procedures, effective February 27, 2026. Here's what billing teams need to do.

Aetna, a CVS Health company, updated Clinical Policy Bulletin 0660, which governs coverage for unicompartmental, bicompartmental, bi-unicompartmental, and total knee arthroplasty. The policy has been modified as of February 27, 2026; billing teams should review all criteria and code groupings against this updated version. If your practice bills CPT 27446, 27447, 27486, or 27487, this policy update directly affects your prior authorization submissions and claim support documentation.

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Quick-Reference Table

Field	Detail Copy
Payer	Aetna, a CVS Health company
Policy	Unicompartmental, Bicompartmental, and Bi-unicompartmental Knee Arthroplasties
Policy Code	CPB 0660 Aetna system
Change Type	Modified
Effective Date	February 27, 2026
Impact Level	High
Specialties Affected	Orthopedic Surgery, Physical Medicine & Rehabilitation, Pain Management, Radiation Oncology
Key Action	Audit conservative therapy documentation before submitting prior auth for CPT 27446 or 27447 — in-person PT notes are now explicitly required

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Aetna Knee Arthroplasty Coverage Criteria and Medical Necessity Requirements 2026

The Aetna knee arthroplasty coverage policy sets a multi-layered medical necessity standard. Members must have advanced joint disease with pain and functional disability that interferes with activities of daily living. The underlying cause must be osteoarthritis, rheumatoid arthritis, avascular necrosis, or post-traumatic arthritis.

Physical examination findings matter here. Aetna requires documented limited range of motion, crepitus, or effusion. You need imaging to support the diagnosis — specifically Kellgren-Lawrence Grade 3 or 4 osteoarthritis, radiographic evidence of avascular necrosis of the tibial or femoral condyle, or imaging showing rheumatoid arthritis with joint space narrowing.

The conservative therapy requirement is where most prior authorization denials originate. Aetna requires 12 weeks of non-surgical treatment for most members. That window extends to 24 weeks for members with relative contraindications to joint replacement. At least half of that therapy must be formal, in-person physical therapy with a licensed physical therapist — not home exercise programs and not virtual PT.

That in-person PT requirement is a hard line. Aetna won't accept virtual therapy or home programs as a substitute for formal PT when calculating whether the conservative therapy threshold is met. Your documentation must show PT notes, not just a physician's attestation that the member completed therapy.

The conservative therapy bundle must include anti-inflammatory medications or analgesics, flexibility and muscle strengthening exercises, activity modification, and supervised in-person physical therapy. For members with relative contraindications, assistive device use and therapeutic knee injections are also required — not optional.

Medical necessity for total knee arthroplasty (CPT 27447) or unicompartmental procedures (CPT 27446) can also be established through alternative pathways. These include failure of a previous osteotomy with pain interfering with ADLs, distal femur or proximal tibia malunion, fracture or nonunion, malignancy of the distal femur or proximal tibia, or failure of a previous unicompartmental knee replacement.

Whether knee arthroplasty is covered under this Aetna coverage policy depends heavily on what's in the chart before the authorization request goes in. Incomplete documentation is the most common reason these requests come back denied.

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Aetna Knee Arthroplasty Exclusions and Non-Covered Indications

Aetna identifies several absolute contraindications that make total joint replacement not medically necessary. If any of these are present, the procedure won't clear medical necessity review regardless of other criteria.

The policy also flags specific procedure types and technologies as non-covered or experimental. Computer-assisted surgical navigation procedures — CPT 0054T, 0055T, and 20985 — fall outside the covered category under this policy. These codes appear in the policy's code set under a separate grouping, signaling that Aetna does not recognize them as medically necessary for knee arthroplasty.

Robotic-assisted surgery billed under HCPCS S2900 is listed separately as well. The policy addresses custom instrumentation for the procedure, and S2900 is explicitly grouped under that designation. Reimbursement for robotic add-on codes is not supported under CPB 0660.

Virtual reality procedural dissociation codes 0771T, 0772T, 0773T, and 0774T appear in the policy code set but are not covered for knee arthroplasty billing. Radiation treatment delivery codes 77402 through 77412 appear in the policy — these follow total knee arthroplasty for heterotopic ossification prevention — but their coverage is procedure-specific and not a standard component of the knee arthroplasty claim.

Patellofemoral-only disease also doesn't meet the imaging threshold. The policy's bone-on-bone articulation exception for conservative therapy only applies to medial and/or lateral compartments — not the patellofemoral compartment.

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Coverage Indications at a Glance

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Aetna Knee Arthroplasty Billing Guidelines and Action Items 2026

This is the section to act on before your next authorization submission. The February 27, 2026 effective date means these standards apply to any claim submitted or auth requested on or after that date.

Copy Action Items

If your practice has a high volume of Aetna knee arthroplasty cases and you're uncertain how these criteria apply to your specific patient mix, talk to your compliance officer before the effective date of February 27, 2026. The conservative therapy documentation requirements, in particular, have enough nuance that a documentation audit is worth doing proactively.

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CPT, HCPCS, and ICD-10 Codes for Knee Arthroplasty Under CPB 0660

Covered CPT Codes (When Selection Criteria Are Met)

Covered HCPCS Codes (When Selection Criteria Are Met)

Code	Type	Description Copy
C1776	HCPCS	Joint device (implantable) — FDA approved device

Not Covered / Experimental Codes

Key ICD-10-CM Diagnosis Codes

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