CurrentAetnaPolicy 0673

Osteoarthritis of the Knee: Selected Treatments

Clinical policy bulletin for selected treatments of knee osteoarthritis governing coverage and medical necessity determinations for Aetna commercial medical plans.

Policy Summary

PayerAetna

PolicyOsteoarthritis of the Knee: Selected Treatments

Policy CodePolicy 0673

Change TypeNo material changes

Effective Date

Next Review Date

Key ActionDocument isolated patellofemoral disease and failure of conservative therapy when requesting coverage for patellofemoral arthroplasty or other advanced interventions.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

11/21/2023last review date

07/25/2024next scheduled review

Zilrettalisted as not medically necessary

Multipleexperimental/investigational

95.8%PFA 5-yr survival

180Moseley trial patients

Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.

Coverage Criteria and Medical Necessity

Medical necessity determinations

Aetna considers the following medically necessary determinations based on clinical presentation and osteoarthritis (OA) severity:

Arthroscopic debridement (with or without partial meniscectomy): Medically necessary for persons presenting with mild-to-moderate (Outerbridge I or II) osteoarthritis with knee pain plus mechanical symptoms due to loose bodies and/or meniscal tears.

Based on Aetna medical necessity statement; excludes Outerbridge III–IV.

Arthroscopic partial meniscectomy: Medically necessary for traumatic meniscal tears unless moderate or severe osteoarthritis (Outerbridge III or IV) is present.

Traumatic tears only; degenerative tears addressed separately under investigational/ not recommended policies.

Intra-articular glucocorticoid injections: Considered medically necessary for the treatment of knee osteoarthritis as part of conservative/injectable management strategies.

Reflects guideline-supported short-term efficacy for knee OA.

Extended-release triamcinolone (Zilretta, J3304): Not medically necessary because it has not demonstrated significant improvement in osteoarthritis pain compared with immediate‑release triamcinolone formulations.

Policy explicitly states Zilretta is considered not medically necessary.

Experimental / investigational

Interventions considered experimental and investigational because effectiveness has not been established:

Experimental/Investigational interventions: Includes arthroscopic partial meniscectomy for degenerative meniscal tears; medial knee implanted shock absorber (MISHA); sustained acoustic medicine (SAM); adipose cell–based therapies (e.g., autologous lipoaspirate); Advanced Arthritis Relief Protocol (including stem cell therapy); stromal vascular fraction injection; stem cell therapies (autologous adipose-derived, bone marrow-derived mononuclear cells, infrapatellar fat pad‑derived MSCs); genicular artery embolization; radiofrequency ablation (where evidence is limited); percutaneous calcium phosphate injections; cryotherapy/cryoneurolysis and other listed interventions when effectiveness is not established.

List reflects policy's enumerated investigational items.

Coverage guidance derived from evidence

Coverage guidance should align with randomized trial and guideline evidence; consider the following when evaluating arthroscopic and related procedures for knee OA:

General rule for arthroscopic lavage/debridement: Arthroscopic lavage and debridement for undifferentiated knee osteoarthritis do not provide additional benefit over placebo or optimized nonoperative therapy and therefore should not be routinely covered.

Supported by Moseley et al (2002), Kirkley et al (2008), AAOS guidance and Cochrane review.

Potential exceptions where arthroscopy may be reasonable: Arthroscopic procedures may be considered when specific mechanical pathology is clearly documented (e.g., symptomatic loose bodies or meniscal tear with clinical correlation to symptoms) and symptoms are not attributable to generalized OA.

Careful patient selection required per guideline and trial context.

Meniscal tear with degenerative features: For degenerative medial meniscal tears without OA, randomized sham‑controlled trials (Sihvonen et al) demonstrated no superiority of arthroscopic partial meniscectomy over sham; coverage requires strong documentation that symptoms are attributable to the tear and that nonoperative therapy failed.

Coverage criteria for PFA

Patellofemoral arthroplasty (PFA) is covered when ALL of the following are documented in the clinical record:

Patient selection: Symptoms attributable to isolated patellofemoral osteoarthritis (PFOA) with significant pain or functional limitation; failure of conservative management prior to surgery.

Ideal candidate typically middle-aged with isolated PFOA and failed nonoperative care.

Imaging and exclusion: Clinical and radiographic evaluation demonstrating minimal or no tibiofemoral osteoarthritis (i.e., disease confined to the patellofemoral compartment).

Studies and trials excluded significant tibiofemoral OA to select PFA candidates.

Implant and technique considerations: Use of modern second‑generation/onlay PFA designs and appropriate surgical technique to minimize patellar instability and optimize outcomes.

Improved outcomes associated with contemporary implant designs and technique.

Patellofemoral Arthroplasty (PFA)

Evidence summary and coverage considerations for Patellofemoral Arthroplasty (PFA):

PFA candidate considerations: Candidate should have isolated patellofemoral osteoarthritis with limited or no tibiofemoral disease and have failed conservative measures; patient selection is critical due to higher revision rates.

Short- to mid-term PROMs may improve after PFA; revision rates higher than TKA; long‑term data limited.

Outcomes evidence: Short- to mid-term patient-reported outcomes may improve after PFA and can be similar to TKA in some studies, but PFA cohorts have higher revision rates and ~25% progression to tibiofemoral degeneration reported in some series.

Randomized and comparative trials show faster recovery and improved early QOL versus TKA in some series; long-term survivorship variable.

Patellar Denervation (circum-patellar electrocautery)

Evidence and considerations for patellar denervation (circum‑patellar electrocautery):

Denervation outcomes: Randomized trials and meta-analyses report mixed results: some early improvements in anterior knee pain and function measures are observed, but benefits often are not sustained at longer follow-up; complication rates are similar between groups.

Evidence does not strongly favor sustained long-term benefit; findings vary across studies.

Cryo-neurolysis / Cryotherapy

Evidence and considerations for cryoneurolysis / cryotherapy:

Cryo-neurolysis considerations: Randomized, sham‑controlled trials (targeting the infrapatellar branch of the saphenous nerve) showed statistically significant reductions in WOMAC pain scores versus sham for up to approximately 150 days; additional single-center and retrospective studies report improved perioperative outcomes, but limitations include potential unblinding, variable responder definitions, and need for replication.

Safety profile acceptable in reported trials; effects may wane over time.

Evidence summaries

Clinical evidence and guideline context for cryoneurolysis and TA‑ER (Zilretta):

Cryoneurolysis evidence: Randomized and non-randomized studies report reduced pain and improved function with cryoneurolysis in some analyses (per‑protocol and ITT), but limitations include unblinding over time, single-site designs, and small sample sizes; AAOS and ACR guidance note limited strength of recommendation.

IMMPACT responder thresholds referenced; replication needed.

TA-ER (Zilretta) evidence vs placebo: Phase‑3 trials demonstrated TA‑ER (FX006) 32‑mg single IA injection produced significant improvement in average daily pain versus saline placebo at week 12 and improved several secondary endpoints; effects lasting ~5–6 months reported in some analyses.week 12 primary endpoint

Pivotal trial met primary endpoint vs placebo; comparisons versus immediate‑release TAcs were mixed.

TA-ER vs TAcs evidence and safety: Head‑to‑head comparisons vs TA crystalline suspension showed mixed results: some exploratory endpoints favored TA‑ER, but primary ADP‑based comparisons versus TAcs were not consistently significant; labeling states efficacy and safety of repeat administration not fully evaluated though single-arm repeat‑dose studies reported tolerability up to two doses.

Coverage-relevant evidence summaries

Coverage‑relevant evidence summaries and inferred implications from the literature:

TA-ER clinical evidence: Randomized phase‑III trials and pooled analyses show TA‑ER 32‑mg single IA injection improved average daily pain, WOMAC subscales, and reduced rescue medication use versus saline placebo and, in some analyses, versus TAcs; generally well‑tolerated with effects lasting ~5–6 months.

Supports consideration as an option for symptomatic knee OA in patients meeting trial criteria (KL grade 2–3, ADP 5–9).

Percutaneous calcium phosphate injections: Small cohort studies report mixed results with a significant proportion of poor outcomes in advanced OA; authors advise against use in patients with advanced osteoarthritic changes.

Evidence insufficient for routine coverage; discouraged in advanced OA.

Arthroscopic meniscal surgery for degenerative tears: Multiple RCTs and systematic reviews (including placebo‑controlled trials) found no clinically meaningful benefit of APM over sham or nonoperative management for degenerative medial meniscal tears without OA; supports conservative management first and limited indications for APM.

Coverage stance for procedural and biologic treatments

Summary coverage stance for procedural and biologic treatments based on reviewed evidence:

APM general recommendation: Do not perform arthroscopic partial meniscectomy (APM) as first‑line therapy for all patients with knee pain and meniscal tear; consider APM only after failure of conservative management and in selected subgroups (e.g., non‑OA knees with unstable tears) where limited RCT evidence suggests benefit.

Randomized trials show no benefit versus placebo in degenerative tears without OA.

Biologic and stem cell therapies: Stem cell therapies, BMAC, autologous fat injections, and other cell‑based interventions remain investigational/unproven due to limited, low‑quality evidence and safety concerns; not recommended for routine clinical use outside clinical trials.

Systematic reviews conclude insufficient evidence and potential adverse events reported.

Other modalities require further evidence: Balneotherapy, ESWT, HTO+BMDC and similar approaches have limited or heterogeneous evidence and require higher‑quality RCTs before broad coverage can be recommended.

Evidence base inconsistent; further research needed.

Coverage-relevant evidence summaries

Coverage‑relevant evidence summaries and guideline positions for selected interventions:

Stem cell therapy: Multiple systematic reviews and clinical studies show limited efficacy, safety concerns (including reports of knee pain, effusion, swelling, and isolated reports of malignancy), and low‑quality study designs; major society guidance recommends against stem cell injections for knee OA.

ACR guideline and comprehensive reviews cited.

Genicular artery embolization (GAE): Small single‑arm studies report improvements in VAS and WOMAC with minor adverse events; evidence is limited and insufficient for broad recommendation.

Promising but requires controlled trials.

High‑intensity laser therapy (HILT): Meta‑analysis of small RCTs suggests reductions in pain and improvements in function, but limited study numbers and heterogeneity reduce certainty of effect.

Larger RCTs needed.

Evidence-based efficacy summaries

Summaries of evidence-based efficacy from systematic reviews, observational studies, and randomized trials:

Genicular RFA evidence: Moderate‑quality evidence indicates fluoroscopically guided genicular RFA reduces pain at a minimum of 6 months with six‑month success rates (>=50% pain relief) ranging from 49%–74% and improved OKS/WOMAC compared with IA steroid or HA.6 months

Fogarty et al systematic review provides pooled estimates and GRADE assessment.

Cryoneurolysis evidence: Randomized, sham‑controlled trials (Radnovich et al) demonstrated statistically significant WOMAC pain improvement up to Day 90 and sustained effects in some responders to Day 150; other observational studies report perioperative benefits but have design limitations.up to 150 days

Effects may diminish over time; safety profile acceptable in trials.

SAM evidence: Small multi‑center studies and systematic reviews report rapid pain reduction and functional improvement with SAM combined with topical diclofenac in short‑term trials, but evidence heterogeneity and confounding (combined topical agent) limit conclusions about long‑term disease‑modifying effects.

Suggested coverage criteria for SAM

Suggested coverage criteria for Sustained Acoustic Medicine (SAM) (clinical context–derived):

Radiographic confirmation: Radiographically confirmed knee OA (Kellgren‑Lawrence grade II or III) with moderate‑to‑severe knee pain documented in the record.KL II/III

Aligned with study populations reported in SAM trials.

Prior conservative therapy: Failure of or inadequate response to conservative therapy (e.g., supervised physical therapy) prior to consideration of SAM.

SAM described as adjunct after failed conservative measures.

Treatment parameters documented: Planned SAM device settings and duration consistent with studied parameters (3 MHz, 0.132 W/cm2, 1.3 W; 4 hours/day delivering ~18,720 J) and any topical adjunct (e.g., 1% diclofenac) specified in documentation.

Documentation should match trial dosimetry.

The policy identifies specific procedures and clinical scenarios that are not supported or are considered investigational. Examples include arthroscopic debridement when patients present with knee pain only or have severe osteoarthritis (Outerbridge grade III–IV), and arthroscopic lavage, which the policy and cited evidence conclude is not indicated for any stage of knee OA. The list of approaches considered experimental or investigational also explicitly includes modalities such as cryotherapy (e.g., Iovera cryoneurolysis), stem cell–based therapies (including stromal vascular fraction and adipose cell–based injections), sustained acoustic medicine (SAM), and other biologic or device-based treatments described in the bulletin.

Randomized trials and systematic reviews cited in the policy show that routine arthroscopic lavage (needle or arthroscopic) provides no additional benefit over optimized nonoperative therapy or sham procedures for patients with knee osteoarthritis. Consequently, the policy states that arthroscopic lavage and debridement for undifferentiated knee OA are not supported, except when there are discrete mechanical indications (for example, symptomatic loose bodies or clearly correlated meniscal pathology). These conclusions are based on high‑quality trials (e.g., Moseley et al, Kirkley et al) and pooled reviews indicating no clinically meaningful improvement compared with nonoperative care or placebo surgery.

The policy advises that patients with significant tibiofemoral osteoarthritis or weight-bearing chondral lesions are poor candidates for isolated patellofemoral arthroplasty (PFA). Clinical series and systematic reviews report that progression of tibiofemoral OA and weight‑bearing chondral damage are frequent causes of early implant failure, and appropriate imaging and clinical documentation excluding substantial tibiofemoral disease are essential when considering PFA.

Evidence addressing modern (second‑generation/onlay) PFA shows improvement in patient‑reported outcomes in some series, but long‑term effectiveness remains uncertain. Systematic reviews and comparative studies report higher revision rates for PFA versus total knee arthroplasty (e.g., pooled revision rates ~8.4% for second‑generation PFA versus ~1.3% for TKA in some analyses), with progression of tibiofemoral OA cited as a common reason for failure. These findings underscore the need for careful patient selection and informed consent regarding revision risk and OA progression.

The manufacturer labeling and pivotal trial reports for extended‑release triamcinolone acetonide (Zilretta, J3304) state that the product is dosed as a single 32 mg intra‑articular injection for knee OA and that the efficacy and safety of repeat administration have not been evaluated; labeling also indicates it is not suitable for use in small joints (eg, hand) and that efficacy/safety for shoulder and hip have not been assessed. The policy therefore treats Zilretta cautiously and, in the medical necessity section, lists the extended‑release preparation as not medically necessary relative to immediate‑release triamcinolone based on comparative data.

In the percutaneous calcium phosphate injection series cited, study eligibility excluded patients with extensive non‑degenerative meniscal tears with a flipped displaced component at the lesion level and those with significant mechanical axis deviation (> 8°). This highlights that candidates for this procedure were tightly selected, and that pain attributable to complex non‑degenerative meniscal pathology was a specific exclusion in the reported cohort.

Comprehensive reviews and guideline assessments conclude that routine clinical use of stem cell products for knee osteoarthritis is not recommended. Systematic reviews found limited, low‑quality evidence, heterogeneous study designs, and reports of adverse events (including knee pain, effusion, swelling and isolated case reports of malignancy in the literature); combined, these factors led the authors and major guideline panels to advise against broad clinical adoption of stem cell injections outside controlled research settings.

Major society guidance and recent systematic reviews uniformly caution that stem cell therapies for knee OA lack standardized preparations and robust evidence of safety or efficacy. The 2019 ACR/Arthritis Foundation guideline specifically recommends against stem cell injections for knee or hip OA, and meta‑analyses conclude that current studies are insufficient to support routine clinical use; clinical application should therefore be limited to research protocols with informed consent.

The 2019 American College of Rheumatology/Arthritis Foundation guideline referenced in the policy strongly recommends against transcutaneous electrical nerve stimulation (TENS) for patients with knee (and/or hip) osteoarthritis, citing low‑quality, small trials that do not demonstrate clinical benefit. The policy reflects this guideline position by listing TENS among interventions not supported for knee OA.

The policy notes recurring limitations across the evidence base for many emerging interventions: frequent reliance on non‑randomized designs, small sample sizes, single‑site or single‑surgeon series, and exclusions (for example, older patients in some device studies) that limit generalizability. These methodological constraints reduce confidence in efficacy and safety estimates and are explicitly cited as reasons to regard some approaches as investigational or to require additional documentation prior to coverage.

Economic evaluations cited in the policy (for example, cost‑effectiveness analyses of Sustained Acoustic Medicine) are limited by assumptions that may not generalize to payer populations: analysts used assumed relationships between Medicare and commercial rates, omitted opioid‑related costs, and did not include complication costs for many interventions. The policy highlights these limitations as factors that constrain firm conclusions about value and could affect coverage decisions that rely on cost‑effectiveness arguments.

Based on the policy conclusions and supporting evidence, extended‑release triamcinolone acetonide (Zilretta, J3304) is listed as not medically necessary. The determination cites comparative trial results and labeling that do not demonstrate consistent superiority over immediate‑release triamcinolone and notes limitations regarding repeat dosing and non‑knee joint indications.

Randomized placebo‑controlled trials and meta‑analyses show that arthroscopic lavage and/or debridement for undifferentiated knee osteoarthritis (patients presenting with OA‑related knee pain only and without discrete mechanical pathology) do not improve pain or function versus optimized nonoperative care or sham surgery. Consequently, the policy states that these arthroscopic interventions are not supported for routine treatment of undifferentiated knee OA.

The policy advises that use of patellofemoral arthroplasty (PFA) in patients with multi‑compartment OA or when implant design/patient factors predict poor outcomes should be approached cautiously and may be considered inappropriate. Evidence summarized in systematic reviews and cohort series links poorer outcomes and higher revision rates to inadequate patient selection and to presence of tibiofemoral disease or weight‑bearing chondral lesions.

Professional guideline and randomized trial evidence regarding cryotherapy/cryoneurolysis are mixed: AAOS did not recommend cryotherapy as a surgical management for knee OA in 2015, and the 2019 ACR/Arthritis Foundation guideline provides only conditional recommendations for thermal modalities due to heterogeneous methods and short duration of benefit. Conversely, a randomized sham‑controlled trial of infrapatellar branch cryoneurolysis showed symptom benefit for up to approximately 150 days, but the policy recognizes limitations in study designs and advocates cautious interpretation of these data.

Some clinical trials of extended‑release triamcinolone (FX006/TA‑ER) did not meet predefined primary endpoints in certain analyses (for example, a Phase IIb trial failed to meet the Week 12 primary ADP endpoint), while other trials showed benefit at various time points. These mixed results are cited in the policy as evidence of insufficient or inconsistent efficacy across all analyses and as a reason for conservative coverage positioning.

Randomized placebo‑surgery trials (notably Sihvonen et al) demonstrate that arthroscopic partial meniscectomy (APM) for degenerative medial meniscal tears in patients without knee osteoarthritis provides no benefit over sham surgery; systematic reviews pooling RCTs reached similar conclusions. These findings underpin the policy stance that APM should not be routine first‑line treatment for degenerative meniscal tears and that documentation of clear indications and failed conservative therapy is required when APM is considered.

The policy explicitly states that using arthroscopic surgery as the first‑line treatment for all meniscal tears is not appropriate, and it similarly warns against broad clinical use of stem cell therapies for knee OA given the limited and low‑quality evidence, safety concerns, and guideline discouragement—supporting a coverage stance that favors conservative management and evidence‑based indications prior to procedural interventions.

Given the lack of consistent efficacy, heterogeneity of preparations and techniques, and reported adverse events in available studies, the policy presents stem cell injections for knee OA as unsupported for routine clinical care. Major guideline statements and systematic reviews cited in the document recommend against routine clinical use and suggest that such therapies remain investigational until high‑quality comparative trials demonstrate benefit and safety.

Adipose cell–based therapies—including stromal vascular fraction (SVF), adipose‑derived stem cells, and minimally manipulated lipoaspirate—are supported by limited, heterogeneous, and generally low‑to‑moderate quality evidence. Early follow‑up studies report symptomatic and sometimes radiologic improvements, but variability in protocols, outcome measures, and limited RCT data mean these approaches are not routinely supported for coverage outside clinical research.

Across many device and biologic studies summarized in the policy, common methodological limitations are identified: retrospective designs, use of historical controls, incomplete capture of preoperative opioid exposure, single‑site or single‑surgeon series, and small sample sizes. These limitations reduce generalizability and increase the risk that observed benefits may not be replicated in broader clinical practice.

The overall evidence base for several emerging knee OA interventions is heterogeneous, with variable outcomes and study quality, short follow‑up duration, and frequent confounding by co‑interventions (for example, use of adjunct topical agents). The policy emphasizes the absence of long‑term disease‑modifying data and the need for rigorous randomized trials before these treatments are adopted widely or covered routinely.

Provider Actions, Documentation and Prior Authorization

Billing Rule

Code-specific coverage linkage

Coverage and billing are code‑linked: certain CPT/HCPCS/ICD‑10 codes are addressed by this policy and coverage is contingent on meeting the policy clinical criteria (e.g., 29874 for removal of loose body; 29880/29881 for meniscectomy; G0289 for debridement at time of other arthroscopy; listed J‑codes for intra‑articular steroids). Verify that the submitted diagnosis codes (for example, M17.x osteoarthritis codes, M23.x/M25.x meniscal/ knee pain codes) support the requested procedure.

Affected CPT/HCPCS examples: 29874, 29880, 29881, G0289, 20610/20611
Affected drug J‑codes for intra‑articular steroids listed in policy

Prior Authorization

Prior authorization considerations

Prior authorization may be suggested or required for several advanced or higher‑cost interventions. When prior authorization is required, substantiate that the patient has failed an appropriate course of conservative therapy (see Conservative Therapy trial callout), document radiographic confirmation of OA (Kellgren‑Lawrence grade when available), and provide rationale and objective findings supporting the selected procedure (e.g., isolated patellofemoral disease for PFA, positive diagnostic block for genicular RFA). For devices/implants and cellular therapies include device identification, implant justification, and prior conservative care history.

CPT/HCPCS/ICD Coding

Covered CPT/HCPCS/ICD codes when selection criteria are metmixedCovered

29874	Arthroscopy, knee, surgical; for removal of loose body or foreign body (eg, osteochondritis dissecans fragmentation, chondral fragmentation).
G0289	Arthroscopy, knee, surgical, for removal of loose body, foreign body, debridement/shaving of articular cartilage (chondroplasty) at the time of other surgical knee arthroscopy in a different compartment of the same knee.
M17.0-M17.9	Osteoarthritis of knee.
M23.000-M23.369	Derangement of meniscus due to old tear or injury.
M25.561-M25.569	Pain in knee.
M25.661-M25.669	Stiffness of knee, not elsewhere classified.
Q68.6	Discoid meniscus.
29880	Arthroscopy, knee, surgical; with meniscectomy (medial AND lateral, including any meniscal shaving) including debridement/shaving of articular cartilage (chondroplasty), same or separate compartment(s), when performed.
29881	Arthroscopy, knee, surgical; with meniscectomy (medial OR lateral, including any meniscal shaving) including debridement/shaving of articular cartilage (chondroplasty), same or separate compartment(s), when performed.
20610	Arthrocentesis, aspiration and/or injection, major joint or bursa (eg, shoulder, hip, knee, subacromial bursa); without ultrasound guidance.

1–10 of 12

1/2

Codes associated with interventions considered experimental/investigational or not coveredmixedNot Covered

0101T	Extracorporeal shock wave involving musculoskeletal system, high energy.
0441T	Ablation, percutaneous, cryoablation; lower extremity distal/peripheral nerve.
0565T	Autologous cellular implant derived from adipose tissue for treatment of knee OA; tissue harvesting and cellular implant creation.
0566T	Injection of cellular implant into knee joint including ultrasound guidance, unilateral.
15876-15879	Suction assisted lipectomy (for percutaneous autologous fat injections).
J0585	Injection, onabotulinumtoxinA, 1 unit.
K1004	Low frequency ultrasonic diathermy treatment device for home use (sustained acoustic medicine).

Definitions and Key Terms

Outerbridge scale — four-grade classification for articular degeneration.

DefinitionFour-grade classification of articular cartilage degeneration by compartment.

Grade ISoftening or blistering of the articular cartilage.

Grade IIFragmentation or fissuring in an area less than 1 cm.

Grade IIIFragmentation or fissuring in an area greater than 1 cm.

Grade IVCartilage erosion down to bone.

Sham/placebo arthroscopy — definition and context.

Definition

Revision History

2023-11-21last_review

Policy was last reviewed on 11/21/2023 as indicated in the policy history.

2003-09-26effective

Policy effective date established as 09/26/2003.

2024-07-25next_reviewLatest

Next scheduled policy review is 07/25/2024.

Policy Summary

PayerAetna

PolicyOsteoarthritis of the Knee: Selected Treatments

Policy CodePolicy 0673

Change TypeNo material changes

Effective Date

Next Review Date

Key ActionDocument isolated patellofemoral disease and failure of conservative therapy when requesting coverage for patellofemoral arthroplasty or other advanced interventions.

SourceLink

On This Page

APM not first-line for degenerative tears; see RCT evidence.

Informed consent/expectations: Documented discussion of risks including progression to tibiofemoral OA and potential need for later revision or conversion to total knee arthroplasty (TKA).

Higher revision rates and progression to tibiofemoral OA are common failure modes.

Labeling: single 32 mg IA injection; repeat administration studied in open‑label trial.

Sihvonen et al and pooled analyses cited.

Intra‑articular glucocorticoid injections: ACR/Arthritis Foundation strongly recommends IA glucocorticoid injections for knee OA for short‑term symptom relief; consider standard IA steroid injections as first‑line injectable therapy.

Guideline supported.

Genicular nerve radiofrequency ablation (RFA): Systematic reviews and RCTs report genicular RFA provides significant pain relief at 6 months (50%+ relief in many patients) and improved function versus intra‑articular steroid or hyaluronic acid; recommendation is conditional due to heterogeneity and limited long‑term data.6 months

Six‑month success rates 49%–74%; RR vs IA steroid ~4.58.

short‑term (days to weeks)

Additional RCTs and longer follow-up required.

Outcomes monitoring: Baseline and follow‑up patient‑reported pain (NRS) and function (WOMAC) recorded; device usability and adverse events monitored and documented.

Trials measured daily NRS and WOMAC and reported safety.

Document failure of conservative therapy (duration and modalities tried)
Provide imaging (radiographs, MRI) and relevant KL grading when available
Include device/implant details and rationale for selection

Note

Prior authorization: not specified in these sections

Some sections of the source discuss FDA labeling and trial data (for example, TA‑ER/Zilretta) but do not state explicit prior authorization requirements. Absence of a stated prior authorization policy in the text does not guarantee coverage — check plan benefit details and prior authorization rules in member's contract.

Zilretta labeling and trial notes present but prior auth not specified in these excerpts
Verify plan‑level prior authorization portals and benefit documents

Prior Authorization

Prior authorization recommended for APM and stem cell therapies

Prior authorization is recommended (or prior review likely to be requested) for arthroscopic partial meniscectomy (APM) and for stem cell / cellular injection therapies because randomized trials and systematic reviews show limited or conflicting benefit and safety concerns. For APM, document failure of conservative management and correlate symptoms to tear (not incidental MRI findings). For stem cell therapies, provide trial evidence, informed consent, and justify investigational use; be aware these interventions are listed as Experimental/Investigational and may be denied.

APM: provide documentation of prior conservative therapy and that meniscal tear is symptomatic (correlate exam, imaging, history)
Stem cell/cellular injections: provide study‑level evidence, informed consent, and acknowledge investigational status

Documentation Required

Diagnostic block and protocol documentation

For procedures that use diagnostic prognostic nerve blocks (for example, genicular RFA or cryoneurolysis), document the block technique, targeted nerve(s), magnitude and duration of pain relief, and timing relative to the index procedure. Use the same outcome measures and follow standardized protocols where available to support expected response.

Record diagnostic block details: drug, dose, guidance modality, target nerve(s)
Document percent pain reduction and duration after block
Include baseline and post‑block outcome scores (e.g., NRS, WOMAC)

Note

Prior authorization (no requirements stated in this excerpt)

Policy metadata lists effective and review dates and indicates no specific prior authorization steps in these excerpts. Providers must confirm any prior authorization or precertification requirements with the member’s plan or portal; a lack of stated requirements in the CPB does not waive plan requirements.

Effective/Next review dates noted in policy history — verify current policy version
Confirm plan‑specific prior authorization requirements via payer portals

Denial Risk

Experimental/Investigational denial risk

Treatments designated as Experimental and Investigational (for example: arthroscopic partial meniscectomy for degenerative tears, MISHA, SAM, most stem cell and adipose‑based therapies, percutaneous calcium phosphate in many contexts) carry a high risk of denial. Submit strong supporting evidence if requesting approval and expect denial if the service is considered investigational by the plan.

Review Experimental/Investigational list before authorization requests
Provide high‑quality peer‑reviewed evidence for coverage exceptions

Denial Risk

CMS non-coverage indication

CMS previously indicated it would issue a national non‑coverage determination that arthroscopic lavage alone is not reasonable and necessary for OA and that arthroscopic debridement is not reasonable and necessary for patients with knee pain only or with severe OA (Outerbridge III/IV). Use CMS guidance when determining medical necessity and prior authorization.

CMS non‑coverage: arthroscopic lavage alone for OA
Arthroscopic debridement not reasonable for knee pain only or severe OA (Outerbridge III/IV)

Documentation Required

Factors associated with revision risk

For procedures with higher revision risk (notably patellofemoral arthroplasty), document factors that increase failure risk such as presence of tibiofemoral chondral lesions in weight‑bearing zones, malalignment, inflammatory arthropathy, obesity, or other comorbidities. When PFA is proposed, include discussion of expected revision risk and alternative options.

Explicitly note chondral lesions in weight‑bearing tibiofemoral areas if present
Describe patient factors that may predispose to early implant failure

Documentation Required

Documentation risk for PFA

Patellofemoral arthroplasty (PFA) carries documentation risk due to higher reported revision rates from progression of tibiofemoral OA and selection errors. When requesting coverage for PFA, provide clear evidence of isolated patellofemoral osteoarthritis (absence of significant tibiofemoral OA), prior adequate conservative therapy, imaging correlates, and rationale for choosing PFA over alternatives (e.g., TKA).

Document isolated PFOA: imaging and compartmental assessment
Provide prior conservative therapy timeline and responses
Explain rationale for implant/component choice

Note

No explicit coverage-denial triggers are stated

The policy text does not enumerate explicit coverage‑denial triggers beyond statements of investigational status and CMS guidance. However, absence of explicit triggers does not prevent denials — insufficient documentation, failure to meet listed selection criteria, or use of investigational services are common grounds for denial.

Denial may follow when selection criteria are unmet or documentation is insufficient
Investigational/experimental procedures listed are common denial triggers

Denial Risk

APM clinical appropriateness risk

Arthroscopic partial meniscectomy (APM) should not be first‑line for degenerative meniscal tears. Trials show little or no benefit compared with placebo or nonoperative care in many patients. Prioritize and document non‑operative care; if surgery is requested, demonstrate mechanical symptoms, symptomatic correlated tear, and failure of conservative measures.

Document conservative therapy attempts and duration prior to APM
Correlate MRI meniscal findings with clinical symptoms (not incidental)

Denial Risk

Stem cell therapy risks and evidence limitations

Stem cell and related cellular therapies for knee OA have limited, heterogeneous evidence and reported adverse reactions (knee pain, effusion, swelling; rare serious events). Major guidelines (ACR/Arthritis Foundation) and systematic reviews express concerns and often recommend against routine use. Treat these as investigational — provide detailed informed consent, evidence, and safety monitoring if requested.

Document risks and uncertain benefits; include informed consent
Provide rigorous study data if seeking coverage

Denial Risk

Evidence insufficiency risk

Many novel interventions are supported by small, uncontrolled, or single‑arm studies. Evidence insufficiency (small sample sizes, short follow‑up, lack of randomization) limits generalizability and is a common reason for non‑coverage. When requesting authorization for such services, include higher‑quality evidence where available and a plan for outcome measurement.

Highlight lack of RCTs or long‑term data for device/therapy under review
Provide plans for post‑procedure outcome monitoring if applicable

Note

Non-randomized study designs and historical controls limit generalizability

Non‑randomized study designs and reliance on historical controls reduce confidence in effectiveness estimates. If the clinical justification relies on such data (for example, ISA studies with historical controls), document the study limitations, applicability to the member, and any propensity‑matching or controlled elements.

Explain limitations of non‑randomized/historical control evidence
Provide patient‑level justification when generalizability is uncertain

Note

Cost-analysis limitations may impact coverage

Cost‑effectiveness or cost‑analysis findings cited in the literature may be sensitive to assumptions (Medicare vs commercial rates, omitted complication costs, regional cost variation). Payers may weigh these limitations in coverage decisions. Do not assume cost‑effectiveness equates to coverage without supporting clinical evidence.

Cost analyses may assume Medicare/commercial rate ratios and national averages
Complication costs and opioid‑related costs may be omitted in some analyses

Note

Clinical Policy Bulletins are guidance — verify benefits

Clinical Policy Bulletins are developed to assist in administering plan benefits and do not constitute offers of coverage or medical advice. This CPB is a partial description of plan benefits — providers must verify member eligibility, coverage, and prior authorization requirements. Participating providers are independent contractors and are responsible for verifying benefits.

This CPB is guidance only — verify benefits and prior authorization
Providers are responsible for confirming coverage with Aetna

Billing Rule

Coding and indication linkage

Coding and indication linkage: submit claims with the CPT/HCPCS codes that reflect the performed service and the supporting ICD‑10 diagnosis that matches the policy’s covered indications. When selection criteria are met, list of covered CPT/HCPCS/ICD‑10 codes in the policy applies; codes listed as experimental or not covered should be avoided unless an exception is documented.

Include both procedure CPT and relevant ICD‑10 diagnosis codes on the claim
Do not submit codes listed as experimental unless an exception is authorized

Documentation Required

Correlation of MRI findings with symptoms

MRI findings (such as incidental meniscal tears) are common and often do not correlate with symptoms. When meniscal surgery or other imaging‑driven interventions are requested, document clinical correlation between MRI findings and patient symptoms (mechanical signs, focal tenderness, onset consistent with injury) rather than relying on imaging alone.

Correlate MRI tear with exam and history to demonstrate symptomatic lesion
Avoid proceeding on incidental MRI findings without clinical concordance

Documentation Required

Required clinical documentation

Required clinical documentation to support authorization or medical necessity includes: history of conservative management (modalities, duration, response), imaging reports (radiographs, MRI), compartmental assessment (for PFA), prior procedural history, and baseline and follow‑up outcome measures (e.g., NRS, WOMAC, OKS).

Conservative therapy documentation: dates, therapies tried, response
Imaging and KL grading where available
Baseline and expected outcome measures (NRS, WOMAC, OKS)

Documentation Required

Required documentation for PFA

For PFA requests specifically, required documentation should include evidence of truly isolated patellofemoral osteoarthritis (no significant tibiofemoral OA), prior failure of conservative measures, rationale for PFA over TKA, implant/component selection rationale, and discussion of revision risk.

Include radiographic compartmental assessment and KL grades
Provide trial of conservative therapy and outcome documentation
Explain implant choice and risk counseling

Documentation Required

Required documentation for cryo-neurolysis

For cryo‑neurolysis or other targeted nerve procedures, document the indication (knee OA pain), the specific nerve targeted (e.g., IPBSN), prior treatments tried and failed, expected duration of benefit, and any diagnostic block response if used.

Specify nerve targeted (IPBSN, genicular branches) and technique
Provide prior conservative therapy and diagnostic block results

Documentation Required

Zilretta labeling & trial documentation

Zilretta (triamcinolone acetonide extended‑release) is FDA‑approved as a single 32 mg intra‑articular injection for knee OA; labeling cautions that repeat administration safety/effectiveness and use in small joints/other joints are not established. Trials showed benefit versus placebo but mixed results versus immediate‑release triamcinolone; document patient selection and prior therapy when requesting coverage.

Zilretta dosing: single 32 mg IA injection; repeat dosing not fully evaluated in pivotal labeling
Document prior therapies and indication (knee OA)

Documentation Required

Documentation for percutaneous calcium phosphate injection eligibility

Percutaneous calcium phosphate injection eligibility in the literature was generally limited to patients with MRI‑confirmed subchondral bone marrow edema lesions in weight‑bearing regions, localized pain to that region on palpation/weight bearing, and failure of conservative therapy (typically >3 months). Exclude patients with extensive non‑degenerative meniscal tears with flipped displaced components or significant mechanical axis deformity.

Require MRI confirmation of subchondral BME in weight‑bearing region
Conservative therapy failure (often >3 months) documented

Documentation Required

Documentation for cellular injections

For cellular injections (BMAC, bone marrow‑derived mononuclear cells), provide trial‑level documentation: study rationale, cell counts/preparation, injection technique, informed consent acknowledging investigational status, and short‑term safety monitoring. Small uncontrolled studies exist; high‑quality RCT data are limited.

Report cell product details (source, concentration, volume) and preparation method
Include informed consent and safety monitoring plan

Documentation Required

Outcome measurement for genicular RFA

Outcome measurement for genicular RFA and similar procedures: include baseline and follow‑up pain/function measures (NRS/VAS, WOMAC, OKS) and standardized timepoints (e.g., 6 months) to assess effectiveness. Many studies report success at 6 months; include these measures in authorization/appeal submissions.

Baseline NRS/VAS and WOMAC/OKS scores
6‑month outcome reporting preferred to align with evidence

Documentation Required