Metatarsal Phalangeal Joint Replacement — CPB 0708 | AETNA Coverage Update

Aetna modified CPB 0708 for metatarsal phalangeal joint replacement, effective November 26, 2025. Here's what billing teams need to know.

Aetna, a CVS Health company, updated its metatarsal phalangeal joint replacement coverage policy under CPB 0708 in Aetna's clinical policy bulletin system. The policy draws a hard line between covered procedures—hemiarthroplasty and silastic total prosthetic replacement—and a long list of devices and approaches Aetna calls experimental or unproven. HCPCS codes L8641 and L8642 are central to reimbursement under this policy, and getting the device and diagnosis pairing right is where most claim denials will happen.

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Quick-Reference Table

Field	Detail Copy
Payer	Aetna, a CVS Health company
Policy	Metatarsal Phalangeal Joint Replacement
Policy Code	CPB 0708
Change Type	Modified
Effective Date	November 26, 2025
Impact Level	Medium
Specialties Affected	Orthopedic Surgery, Podiatry, Foot & Ankle Surgery
Key Action	Audit implant device selection and confirm it maps to L8641 or L8642 before billing; claims tied to excluded devices will deny regardless of diagnosis

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Aetna Metatarsal Phalangeal Joint Replacement Coverage Criteria and Medical Necessity Requirements 2025

Aetna's coverage policy for MTP joint replacement is narrow by design. The policy covers procedures only for patients with disabling arthritis of the first metatarsal phalangeal joint—what clinicians call hallux rigidus. That diagnosis maps to ICD-10 codes M20.20, M20.21, and M20.22.

Two procedure types meet Aetna's medical necessity standard. First, hemiarthroplasty of the first MTP joint. Second, total prosthetic replacement arthroplasty using silastic implants—specifically the In2Bones Reference Toe System (RTS) Implant and the Primus Flexible Great Toe Implant. Those are the only named devices Aetna considers medically necessary under this coverage policy. Everything else is on the exclusion list.

CPT 28291 (hallux rigidus correction with cheilectomy, debridement, and capsular release of the first metatarsophalangeal joint) is covered when selection criteria are met. HCPCS L8641 and L8642 are the device codes Aetna maps to the In2Bones RTS and Primus Flexible implants. If you're billing these codes, the implant documentation in the operative note must match one of those two named devices. Anything else and you're heading toward a claim denial.

The policy does not explicitly state prior authorization requirements within CPB 0708 itself, but Aetna MTP joint replacement billing for surgical implant procedures commonly triggers prior auth review under member benefit plans. Check the individual member's plan documents before scheduling. Assuming no prior auth is required because the policy doesn't mandate it is a costly mistake.

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Aetna Metatarsal Phalangeal Joint Replacement Exclusions and Non-Covered Indications

This is where the policy gets detailed—and where your billing team needs to pay close attention. Aetna lists seven categories of excluded procedures and devices. Each one is considered experimental, investigational, or unproven because, in Aetna's words, "effectiveness and durability has not been established."

Here's the exclusion list in full. None of these will get covered under CPB 0708:

The Cartiva Synthetic Cartilage Implant deserves a specific callout. It's widely used, and some practices still have it in their charge capture workflows from earlier periods when coverage was more ambiguous. Under this policy, it's explicitly experimental. If your surgeons still use Cartiva, claims to Aetna will deny under CPB 0708 as updated.

The METIS prosthesis and ToeFit-Plus prosthesis also get a second mention in the HCPCS code notes. HCPCS L8641 and L8642—while listed as covered device codes for the In2Bones RTS and Primus Flexible implants—are explicitly not covered when billed for the METIS or ToeFit-Plus. That's a nuance worth flagging in your charge capture system so the wrong device doesn't trigger an erroneous L8641 or L8642 claim.

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Coverage Indications at a Glance

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Aetna Metatarsal Phalangeal Joint Replacement Billing Guidelines and Action Items 2025

This policy update has a clear financial exposure point: device-to-code mismatch. Get the implant documentation and HCPCS code aligned, or expect denials. Here are the specific steps your billing team should take.

Copy Action Items

If your practice has a high volume of MTP surgeries and your surgeons use a mix of the approved and excluded devices, loop in your billing consultant now. The line between covered and excluded is entirely device-specific, and the reimbursement exposure across a full surgical schedule adds up fast.

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CPT, HCPCS, and ICD-10 Codes for Metatarsal Phalangeal Joint Replacement Under CPB 0708

Covered CPT Codes (When Selection Criteria Are Met)

Code	Type	Description Copy
28291	CPT	Hallux rigidus correction with cheilectomy, debridement, and capsular release of the first metatarsophalangeal joint

Other CPT Codes Related to CPB 0708

Code	Type	Description Copy
26535	CPT	Arthroplasty, interphalangeal joint; each joint
26536	CPT	Arthroplasty, interphalangeal joint; with prosthetic implant, each joint

Covered HCPCS Device Codes (In2Bones RTS and Primus Flexible Implants Only)

Code	Type	Description	Notes Copy
L8641	HCPCS	Metatarsal joint implant	Not covered for METIS® prosthesis or ToeFit-Plus™ prosthesis
L8642	HCPCS	Hallux implant	Not covered for METIS® prosthesis or ToeFit-Plus™ prosthesis

Other HCPCS Codes Related to CPB 0708

Code	Type	Description Copy
L8658	HCPCS	Interphalangeal joint spacer, silicone or equal, each

Key ICD-10-CM Diagnosis Codes

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