CurrentAetnaPolicy 0637

Osteochondral Autografts (Mosaicplasty, OATS)

Clinical policy governing Aetna coverage of osteochondral autograft procedures (mosaicplasty, OATS) primarily for knee articular cartilage defects, including medical necessity criteria and procedures considered experimental/investigational. Affects providers submitting claims for these procedures under Aetna benefit plans.

Policy Summary

PayerAetna

PolicyOsteochondral Autografts (Mosaicplasty, OATS)

Policy CodePolicy 0637

Change TypeNo material changes

Effective DateAug 16, 2002

Next Review DateJul 11, 2024

Key ActionObtain prior authorization and document skeletal maturity, lesion size/location, prior conservative therapy failure, and imaging to support medical necessity.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

7medical necessity criteria required (ALL must be met)

>=15 yrsskeletal maturity example age for eligibility

<55 yrsage generally considered not candidate for total knee replacement

grade III/IVlesion depth required (full thickness)

600 mm2lesion size above which poorer results reported

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.

07/11/2024next scheduled review

Coverage and Medical Necessity

inv-01: Medical Necessity — Covered when ALL of the following are met

Covered when ALL of the following are met:

Aetna medical necessity criteria for osteochondral autografts (knee)

Skeletal maturity: Member is skeletally mature with documented closure of growth plates (e.g., 15 years or older)
Age/Total knee replacement candidacy: Member is not considered a candidate for total knee replacement (i.e., member is under 55 years of age)
Conservative therapy failure: Member has disabling symptoms limiting ambulation that have not been relieved by appropriate non-surgical therapies (e.g., medication, physical therapy)
Lesion characteristics: Focal, full thickness (grade III or IV) unipolar lesions on the weight bearing surface of the femoral condyles or trochlea
Surrounding cartilage: Minimal to absent degenerative changes in the surrounding articular cartilage (Outerbridge grade II or less) and normal appearing hyaline cartilage surrounding border of defect
Knee stability/alignment: Stable and aligned knee with intact meniscus and normal joint space on X-ray (corrective procedure may be necessary in combination with or prior to implantation)
Opposing surface: Opposing articular surface should be generally free of disease or injury

inv-02: Experimental and Investigational — Not covered / considered experimental and investigational

Not covered / considered experimental and investigational:

Procedures considered experimental/investigational

Agili-C for the treatment of osteoarthritis
Autologous cartilage chip transplantation for osteochondral repair
Biologic augmentation (e.g., use of bone marrow concentrate or platelet-rich plasma) for operative treatment of osteochondral defects of the knee
Adipose-derived stem cells + mosaicplasty: Combination of adipose-derived stem cells and mosaicplasty for repair of osteochondral defects
Combination ACI and OATS:

inv-03: Washington State HCA coverage conditions (external committee) — Coverage stance reported by an external agency

Coverage stance reported by an external agency (Washington State HCA):

Knee coverage conditions: Osteochondral allograft/autograft transplantation for the knee is covered when ALL of the following are met: (1) patient age less than 50 years (older at agency discretion); (2) joint does not have malignancy, degenerative or inflammatory arthritis; and (3) there is a single focal full-thickness articular cartilage defect.

The Committee stated procedures are not covered for joints other than the knee.

inv-04: Evidence-informed coverage considerations — Evidence-supported considerations that could inform coverage criteria

Evidence-supported considerations that could inform coverage criteria:

Lesion size and location: RCT evidence for superior mosaicplasty versus microfracture pertains to focal full-thickness femoral condyle/trochlea lesions approximately 2–6 cm2 (median 3.5 cm2 in key RCT); guidelines suggest <2 cm2 best treated with microfracture or OAT, 2–4 cm2 with OAT or ACI, and >4 cm2 with ACI or OCA.lesion size 2-6 cm2 for key RCT

Patient age: Key randomized trial included patients aged 18–50 years and reported durability benefits for mosaicplasty over microfracture with minimum 15-year follow-up in that age group.age 18-50 years in RCT

Durability and failure risk: Comparative data show higher long-term failure rates for microfracture versus OAT (e.g., MFX failure ~66% vs OAT ~51% in comparative cohort) and shorter time to failure with microfracture.

inv-05: Indications for surgical treatment (elbow OCD) — Surgical consideration and timing

Surgical consideration and timing:

Indications for surgery in capitellar OCD: Surgery should be considered if there is no radiographic improvement within 3 months of conservative treatment, or if lesions cause pain in daily activities, produce locking, or are assessed by imaging as obviously unstable; small lesions (≤1.2 cm diameter) may be treated with arthroscopic debridement/loose body removal, while larger lesions (>1.2 cm) may require preservation/reconstruction (eg, fixation or OAT).no radiographic improvement within 3 months

inv-06: Outcomes by treatment modality (skeletally immature OLT) — Comparative outcomes summary

Comparative outcomes (skeletally immature osteochondral lesions of the talus):

Reported pooled clinical success rates: Conservative treatment pooled success ~44% (n=192); bone marrow stimulation (BMS) pooled success ~77% (n=97); retrograde drilling pooled success ~95% (n=22); fixation ~79% (n=33); osteochondral autograft ~67% (n=9).pooled percentages per treatment

Radiologic success (MRI) by treatment: MRI-based radiologic success: conservative ~29% (n=31); BMS ~81% (n=37); retrograde drilling ~41% (n=19); fixation ~87% (n=19); osteochondral transplantation MRI data not reported.pooled percentages per imaging modality

inv-07: Efficacy and safety outcomes for OAT (elbow) — Outcomes for OAT in capitellar OCD

Outcomes for OAT in capitellar OCD:

Functional outcomes and return to sport: OAT/OATS series and systematic reviews report significant improvements in clinical scores and ROM with high return-to-play rates (range 62–100%; pooled ~94% in one review); mean time to unrestricted return approximates 3–6 months in many series.return-to-play range

Complications and graft incorporation: Reported complication rates range across studies (0–11%); donor-site morbidity from knee autografts generally low; post-operative MRI often shows high rates of graft incorporation (eg, 86–93% restoration/incorporation reported in adolescent series).complication and incorporation rates

inv-08: Combination and experimental adjuncts — Adjunct and combination approaches

Adjunct and combination approaches:

Hybrid and experimental adjuncts: Combination approaches (eg, mosaicplasty with adipose-derived stem cells and BMP4 hydrogel in animal models; single-case reports of ACI combined with OAT in humans) have been described to improve integration or treat larger defects, but human clinical evidence is preliminary and limited.preliminary evidence

inv-09: Indication by lesion grade (capitellar OCD) — Indication by lesion grade (capitellar OCD)

Evidence-based considerations and comparative conclusions from reviews:

Surgical indication summary: Surgical treatment (including OAT/OATS) is favored over non-operative management for unstable/high-grade capitellar OCD lesions (UGS grades 3–4); non-operative management may suffice for low-grade/stable lesions (UGS grades 1–2).

inv-10: Talar osteochondral lesion treatment outcomes — Evidence on talar osteochondral lesions

Evidence on talar osteochondral lesions:

Talar OCL surgical outcomes: Various surgical options (microfracture, autograft transplantation, ACI) show improvement over pre-operative status; pooled return-to-sport rates for autograft transplantation are high (~90% in pooled analyses), but outcomes vary with lesion size and technique; evidence quality is low and heterogeneous.

inv-11: Patellar chondral defect considerations — Patellar cartilage defect management evidence

Patellar cartilage defect management evidence:

Patellar high-grade focal defects: OAT can produce good mid-term functional and imaging results for isolated high-grade patellar chondral defects in young patients (defect sizes ~1–2.5 cm2); osteochondral allograft (OCA) is an option for larger or salvage cases but has substantial re-operation and long-term survivorship concerns.

inv-12: Vascularized MFC autograft evidence — Advanced/vascularized grafting

Advanced/vascularized grafting:

Vascularized MFC autograft evidence: Preliminary randomized data suggest vascularized medial femoral condyle (MFC) autografts may provide superior pain relief and functional improvement versus cancellous bone grafting for selected talar lesions (Berndt and Harty II–III), but larger multicenter RCTs are needed to confirm findings.

inv-13: Evidence synthesis relevant to coverage — Summary of clinical evidence and factors relevant to coverage

Summary of clinical evidence and factors relevant to coverage decisions:

Evidence limitations: Most studies are small, single-center, retrospective (level IV) or non-randomized, with heterogeneous methods and outcome reporting; lack of long-term comparative data limits strength of evidence for broad coverage decisions.

Procedures with reported short- to mid-term benefit: Case series and small cohort studies report short- to mid-term improvements after OAT/OCA and some cell-free scaffolds (eg, Agili-C) in selected patients, but follow-up and imaging outcomes are variable and re-operation rates are non-trivial.

Risk and re-operation: Reported re-operation/failure rates vary across series (eg, Agili-C revision ~9.3%; cryo-preserved OCA re-operation ~21.1% in a series); conversion to arthroplasty occurred in some cohorts—counsel patients regarding re-operation and uncertain long-term durability.

Adjunct and confounding factors:

Osteochondral autograft procedures (OATS/mosaicplasty) performed in joints other than the knee (including ankle, elbow, hip, patella, and shoulder) are identified in this policy as procedures that are considered outside the primary covered indications. The policy explicitly lists these non-knee joint procedures among techniques that are excluded or considered investigational, and notes uncertainty about patient selection criteria and long-term effectiveness for non-knee applications.

When evaluating requests for osteochondral autograft procedures outside the knee, reviewers should note the policy’s distinction that the primary coverage criteria and supporting randomized-trial evidence pertain to focal, full-thickness defects of the femoral condyles or trochlea. Use of osteochondral autografts in other joints lacks the same evidence base and therefore is treated as not supported by the coverage criteria in this document.

The Washington State Health Care Authority assessment and Committee concluded that osteochondral allograft/autograft transplantation is a covered benefit only for the knee (and possibly the talus) under specific conditions: patient age less than 50 years (older at agency discretion), absence of malignancy or degenerative/inflammatory arthritis in the joint, and presence of a single focal full-thickness articular cartilage defect. The Committee explicitly stated that osteochondral autograft/allograft transplantation is not covered for joints other than the knee.

Techniques that use synthetic bi-phasic implants (for example, the TruFit plug) or non-autologous mosaicplasty with resorbable synthetic fillers have inconsistent and limited evidence. Systematic reviews and long-term series report early clinical improvements but discordant MRI or histologic findings, incomplete subchondral bone ingrowth, and, in some cohorts, deterioration of early gains over time.

Clinical series report high re-operation rates and poor restoration of subchondral bone architecture with certain synthetic devices (for example, small patellar series showed a 70% re-operation rate for implant failure), and authors have concluded that randomized controlled trials comparing these synthetic implants with established treatments are needed before routine clinical use can be supported.

The available evidence for many osteochondral autograft and adjunct techniques is limited in quality: most studies are retrospective case series (Level IV), single-center reports with small sample sizes, heterogeneous patient populations, variable lesion sizes and concomitant procedures, and short to mid-term follow-up. These limitations reduce generalizability and the strength of conclusions about long-term effectiveness.

Because higher-quality randomized comparative trials are largely lacking for many of the procedures and devices discussed, the policy emphasizes caution in extrapolating positive short-term results to broader coverage decisions and notes that further high-level studies are needed.

For high-grade capitellar osteochondritis dissecans lesions, the literature does not provide sufficient evidence to support routine use of complex reconstructive techniques over simpler options such as microfracture/debridement or fragment fixation. Systematic reviews report that while surgical treatment is superior for unstable/high-grade lesions overall, there is insufficient comparative evidence to demonstrate that advanced reconstructive procedures confer additional benefit for high-grade capitellar lesions.

Osteoarthritis is generally considered a contraindication to many cartilage repair techniques. Studies of the cell-free osteochondral scaffold Agili-C enrolled patients with mild-to-moderate knee OA (Kellgren-Lawrence grade 2–3) and limited defect burden (up to a total defect size of 7 cm2); the policy notes that use of these scaffolds in patients with more advanced OA or outside the studied defect criteria is not supported by the available reports.

The policy states that use of osteochondral autografts for osteoarthritis of the knee and for non-correctable deformities or disorders of joints other than the knee is not supported for the indications listed. In other words, osteochondral autograft transplantation is not considered appropriate to treat diffuse osteoarthritic changes or joints with non-correctable malalignment.

Synthetic resorbable polymers (for example, TruFit, TruGraft, PolyGraft) and non-autologous mosaicplasty approaches currently lack sufficient high-quality evidence to establish safety and effectiveness as alternatives to autograft or allograft. The policy cites studies showing inconsistent incorporation and subchondral bone restoration, deterioration of early improvements in longer follow-up, and high implant failure rates in some series, supporting the position that these techniques remain investigational.

Randomized trials and systematic reviews indicate that microfracture (bone marrow stimulation) may have higher early failure rates and inferior long-term outcomes compared with osteochondral autograft transfer (OAT) or cell-based cartilage repair (ACI/MACI) for larger focal lesions. Network meta-analyses and level I trials rank microfracture below restorative techniques, particularly for lesions larger than small focal defects, and report higher poor-result rates and earlier failures with microfracture.

Combination therapies and novel adjunctive approaches (for example, biologic augmentation, adipose-derived stem cells combined with mosaicplasty, or hybrid ACI/OATS) have been described in animal models and small human reports, but human clinical evidence is preliminary. Owing to heterogeneity and low-quality data, these combination strategies are considered investigational pending larger, controlled studies.

For low-grade, stable capitellar OCD lesions (UGS grades 1–2), systematic reviews report that non-operative management can provide outcomes similar to surgical treatment. Consequently, routine surgical OAT/OATS for these low-grade lesions is not supported by the aggregate evidence and conservative management is a reasonable initial approach.

Clinical experience with cell-free osteochondral scaffolds such as Agili-C shows some short- to mid-term improvements in selected patients, but the trials enrolled patients with mild-to-moderate OA and limited defect sizes. Use of these scaffolds outside the specific studied criteria (for example, in advanced OA or larger/more numerous defects) lacks supporting evidence and is not endorsed by the available reports.

Billing and Procedure Codes

Covered CPT Codes (if selection criteria met)CPTCovered

27416	Osteochondral autograft(s), knee, open (eg, mosaicplasty) (includes harvesting of autograft[s]) [except to repair chondral defects of the patella] [excludes synthetic resorbable polymers]
29866	Arthroscopy, knee, surgical; implantation of osteochondral autograft(s) (e.g., mosaicplasty) (includes harvesting of autografts) [except to repair chondral defects of the patella] [excludes synthetic resorbable polymers]

CPT Codes not covered for indications listed in CPBCPTNot Covered

27412	Autologous chondrocyte implantation, knee
28446	Open osteochondral autograft, talus (includes obtaining graft(s)) [excludes synthetic resorbable polymers]

Other related CPT CodesCPT

0232T	Injection(s), platelet rich plasma, any site, including image guidance, harvesting and preparation when performed
27447	Arthroplasty, knee, condyle and plateau; medial AND lateral compartments with or without patella resurfacing (total knee arthroplasty)
29871	Arthroscopy, knee, surgical; for infection, lavage and drainage
29874	Arthroscopy, knee, surgical; for removal of loose body or foreign body
29877
29879	Abrasion arthroplasty (includes chondroplasty where necessary) or multiple drilling or microfracture
29885	Drilling for osteochondritis dissecans with bone grafting, with or without internal fixation (including debridement of base of lesion)
29886	Drilling for intact osteochondritis dissecans lesion
29887	Drilling for intact osteochondritis dissecans lesion with internal fixation

HCPCS Codes covered if selection criteria metHCPCSCovered

J7330	Autologous cultured chondrocytes, implant [except minced articular cartilage (whether synthetic, allograft or autograft)]
S2112	Arthroscopy, knee, surgical, for harvesting of cartilage (chondrocyte cells)

Other HCPCS Codes related to CPBHCPCS

P9020

Platelet rich plasma, each unit

ICD-10 Codes covered if selection criteria metICD-10Covered

M23.000 - M23.92	Internal derangement of knee [articular cartilage defect]
M25.161 - M25.169	Fistula, knee [articular cartilage of knee]
M25.861 - M25.869	Other specified joint disorders, knee [articular cartilage of knee]
M92.40 - M92.52	Juvenile osteochondrosis of lower extremity [excluding foot]
M93.261 - M93.269	Osteochondritis dissecans knee

ICD-10 Codes not covered for indications listedICD-10Not Covered

M17.0 - M17.9	Osteoarthritis of knee
M21.861 - M21.869	Other specified acquired deformities of lower leg [non-correctable varus or valgus deformities]

Lesion size threshold — clinical relevance

Lesion size thresholdLesions <= 600 mm2 associated with better results; lesions >600 mm2 associated with increasing fibrous formation and poorer outcomes

Authorization, Documentation, and Prior-Approval Guidance

Prior Authorization

Prior Authorization Required

Prior authorization required for covered procedure codes — PA required for primary covered procedure codes and related codes.

CPT 27416, 29866 covered when selection criteria are met; related CPT/HCPCS listed in policy (see CPT/HCPCS lists for covered, not covered, and related codes).
Prior authorization consult the full policy bulletin for any PA rules not specified in this segment.

Prior Authorization

Confirm Indication and Patient Selection

Confirm indication and patient selection prior to authorization — Washington State HCA limited coverage examples: typically knee (and possibly talus) only, age less than 50 years in many agency recommendations, exclusion of degenerative/inflammatory arthritis and malignancy.

WA HCA recommendations: age <50 years (older at agency discretion); single focal full-thickness defect; exclude arthritis/malignancy.
Procedures for joints other than the knee generally not covered by the WA committee.

Clinical Background and Definitions

Articular cartilage has very limited intrinsic regenerative capacity. Untreated full-thickness cartilage defects may lead to pain, synovitis, loose bodies, and progression toward osteoarthritis. Osteochondral autograft techniques (mosaicplasty, OATS) transplant hyaline cartilage and underlying subchondral bone from low weight-bearing donor sites to focal defects to restore surface congruity; these procedures can provide short- to mid-term symptomatic and functional improvement, but long-term durability is variable and evidence is strongest for small to medium focal lesions of the knee.

Mosaicplasty — definition and procedural summary

DefinitionMosaicplasty is transplantation of multiple small cylindrical osteochondral grafts (4–10 mm diameter, ~15–20 mm deep) harvested from low weight-bearing surfaces and placed in a mosaic-like fashion into a prepared focal cartilage/osteochondral defect

ApproachCan be performed open or arthroscopically when few grafts are needed; typically indicated for larger but discrete knee defects

Goal/outcomeAims to restore a smooth hyaline or hyaline-like articular surface with relatively short rehabilitation (normal daily activity often allowed after 5–8 weeks)

Policy Summary

PayerAetna

PolicyOsteochondral Autografts (Mosaicplasty, OATS)

Policy CodePolicy 0637

Change TypeNo material changes

Effective DateAug 16, 2002

Next Review DateJul 11, 2024

Key ActionObtain prior authorization and document skeletal maturity, lesion size/location, prior conservative therapy failure, and imaging to support medical necessity.

SourceLink

On This Page

Combination of autologous chondrocyte implantation and osteochondral autograft transfer for repair of knee osteochondral lesions

Hybrid ACI/OATS: Hybrid autologous chondrocyte implantation performed with osteochondral autograft transfer system (Hybrid ACI/OATS)

Minced articular cartilage (synthetic, allograft or autograft) to repair osteochondral defects of ankle or knee

Non-autologous mosaicplasty with resorbable synthetic fillers: Non-autologous mosaicplasty using resorbable synthetic bone filler materials to repair osteochondral defects of the ankle

Osteochondral autografts of tibial plafond: Osteochondral autografts/allografts for treatment of osteochondral lesions of the tibial plafond (distal tibia)

Osteochondral autografts of other joints: Osteochondral autografts (OATS, mosaicplasty) of joints other than the knee (ankle, elbow, hip, patella, shoulder)

Freiberg disease and non-knee joints: Osteochondral autograft transplantation for treatment of Freiberg disease or to repair chondral defects of elbow, patella, shoulder, or joints other than the knee

Synthetic resorbable polymers (eg, PolyGraft BGS, TruFit, TruGraft) to repair osteochondral articular cartilage defects

MFX failure > OAT failure

Alternative techniques evidence: Synthetic plugs (eg, TruFit), minced cartilage, and various biologic adjuncts report mixed or preliminary results and lack high-quality long-term RCT evidence; consider these investigational pending stronger data.insufficient high-quality long-term RCT evidence

Many studies include concomitant procedures (eg, realignment) and variable patient factors (instability, activity level, smoking) that confound outcome attribution; documentation should specify concurrent procedures and patient factors when seeking authorization.

Prior Authorization

Lesion Size and Age Must Align With Evidence

Prior authorization: lesion size and age alignment — Ensure lesion characteristics and patient age align with evidence when requesting authorization (example study criteria shown).

Study inclusion example: age 18–50 years; defects 2–6 cm2; 1–2 focal full-thickness defects on femoral condyles or trochlea.
Many studies and guidance focus on patients <50 years; document skeletal maturity (physeal closure) for younger patients.

Documentation Required

Document Instability and Prior Management

Authorization likely requires documentation of instability and prior management — For capitellar OCD and similar indications, authorization should document lesion stability, prior conservative management, and imaging evidence.

Document plain radiographs, CT, and MRI findings assessing stability (e.g., displaced fragment, high T2 signal interface).
Document failure of conservative care after an appropriate trial (e.g., 3 months) for lesions expected to respond to non-operative care.

Documentation Required

Authorization Documentation: Lesion Size, Prior Therapies, and Imaging

Prior authorization should document lesion size, prior therapies, and imaging — Studies routinely report lesion size, number of grafts, MRI follow-up (MOCART/OCAMRISS), and validated functional scores; include these in authorization requests.

Report lesion size (mm2 or cm2), number of grafts/plugs used, donor plug diameter when applicable.
Include pre- and post-op validated outcome measures (IKDC, Lysholm, WOMAC, Kujala, KOOS, Timmerman) and MRI scoring (MOCART, OCAMRISS) at specified follow-ups (commonly 6 months and beyond).
Document prior non-surgical therapies tried (medication, physical therapy) and any prior surgical treatments (e.g., microfracture, fixation).

Prior Authorization

Pre-authorization for Novel Scaffolds Recommended

Pre-authorization advisable for novel scaffolds and cell-free implants due to limited evidence — Devices like Agili-C and MaioRegen have short- to mid-term data; longer-term and comparative evidence is limited.

Document specific scaffold/device used and provide clinical rationale and supporting literature.
Consider additional review for cell-free osteochondral scaffolds given limited quality of evidence and lack of long-term outcomes.

Documentation Required

Conservative Therapy Required Before Authorization

Conservative therapy prerequisite — Document failure of appropriate non-surgical therapies prior to authorization; claims may be denied if medical necessity criteria are not met.

Non-surgical therapies include medications and physical therapy; for some joints, a defined trial duration (e.g., 3 months) may be expected.
Policy requires symptomatic, disabling lesions not relieved by appropriate non-surgical therapies.

Step Therapy

Consider Prior Marrow Stimulation / Step Therapy

BMS often considered before OATS; step-therapy considerations — Bone marrow stimulation (microfracture) is commonly used as an initial surgical strategy for small lesions; microfracture has higher early failure and poorer long-term outcomes versus OAT in some studies.

For small lesions (e.g., tibial plafond <150 mm2), marrow stimulation is frequently first-line.
Consider documenting why OATS is preferred over microfracture (e.g., lesion size, prior failure of microfracture, athlete status).

Documentation Required

Essential Clinical Documentation Elements

Clinical documentation to support medical necessity — Include skeletal maturity, age, lesion grade and location, prior non-surgical therapy failure, validated baseline functional scores, and imaging to support the request.

Skeletal maturity (growth plate closure) or age thresholds used in studies (commonly ≥15 years).
Lesion grade (Outerbridge III/IV), unipolar focal defects on weight-bearing femoral condyles or trochlea, and minimal surrounding degenerative change (Outerbridge ≤II).
Baseline validated scores (IKDC, Lysholm, KOOS, AOFAS, Timmerman) and prior treatment history.

Note

Background and Literature

Background and literature — This segment contains background, systematic reviews, RCTs, and case series that inform coverage rationale; evidence limitations may trigger additional review.

Evidence base includes RCTs, comparative studies, systematic reviews, and case series with heterogeneity in populations, lesion sizes, and outcomes.
Limitations: small sample sizes, variable methodologies, short- to mid-term follow-up, and lack of long-term comparative data.

Note

Policy History and Review Dates

Policy history and review dates — Providers should refer to the full policy bulletin for the complete review history and dates; note effective and next review dates.

Policy Number: 0637. Effective Date: 2002-08-16.
Latest review entry shown: 11/20/2023. Next Review: 07/11/2024.
Consult the policy bulletin for full review history and definitions links.

OATS (Osteochondral Autograft Transfer System) — definition and procedural summary

DefinitionOATS (Osteochondral Autograft Transfer System) uses a larger single osteochondral plug (cored) to fill a medium-sized discrete defect, often arthroscopically and sometimes in conjunction with ACL reconstruction

Distinction from mosaicplastyWhereas mosaicplasty transplants multiple small cylinders, OATS commonly transplants a single larger plug that may fill an entire defect

IndicationsEmployed for medium-sized, discrete articular defects of the knee and similar joints

Non-autologous mosaicplasty / synthetic grafts — definition and description

DefinitionNon-autologous mosaicplasty involves drilling multiple holes in the defect and packing them with synthetic resorbable polymers or bone void fillers that act as a scaffold and are gradually resorbed and replaced by bone

RationaleProposed advantage is avoidance of donor-site harvest and morbidity by using synthetic graft material as an osteoconductive scaffold

Evidence/statusInsufficient evidence currently to support safety and effectiveness compared with autograft; considered investigational in this policy context

Donor site morbidity — definition and clinical considerations

DefinitionDonor site morbidity refers to clinical problems at the cartilage/bone harvest site after osteochondral autograft or chondrocyte harvest

Reported frequencyWhen quantitatively assessed, donor-site problems have been reported variably and can affect more than 50% of patients in some series

Clinical considerationHarvest decisions should weigh donor-site risk and alternatives; efforts to identify safer donor sites or techniques that obviate biopsy are needed

OAT / mosaicplasty — definition and intent

Definition/intentOAT / mosaicplasty entails harvesting autologous osteochondral plugs (bone + hyaline cartilage) from less weight-bearing areas and transplanting them to focal full-thickness defects to restore articular surface and subchondral bone

Typical donor/recipientCommon donor sites include peripheral femoral condyle; recipient sites are focal weight-bearing surfaces (eg, femoral condyles, trochlea)

Clinical useOften indicated for small-to-intermediate defects and high-demand patients seeking durable hyaline cartilage restoration

TruFit plug — definition and clinical concerns

DefinitionTruFit plug is a bi-phasic synthetic resorbable scaffold designed to stimulate cartilage and subchondral bone formation

Clinical findings/concernsStudies report early clinical improvement but inconsistent long-term bone ingrowth, mixed MRI/histologic results, and some longer-term deterioration of early gains

Evidence statusNo data demonstrate superiority or equivalence to established treatments; further RCTs are needed before routine clinical use is supported

Minced cartilage / ACC — single-stage technique description

Technique descriptionMinced cartilage / autologous cartilage chip (ACC) is a single-stage, minimally invasive procedure that implants small pieces of autologous (or juvenile allograft) cartilage onto a scaffold to repopulate a defect without in vitro cell expansion

Product examplesTechnologies include CAIS (DePuy Mitek) and DeNOVO NT (juvenile donor cartilage)

Evidence/statusRandomized comparative trials are lacking; high-quality long-term studies are needed to establish safety and effectiveness over standard methods

OAT / OATS / mosaicplasty — surgical transfer (donor/recipient sites)

Surgical transferOAT/OATS/mosaicplasty involve harvesting cylindrical osteochondral plugs from a non-weight-bearing donor site (often lateral femoral condyle) and transplanting them into prepared defects on weight-bearing surfaces to restore contour and hyaline cartilage

Donor sitesDonor grafts are commonly taken from low weight-bearing periphery of the femoral condyles; some series have used costal grafts

Recipient sitesRecipient sites include focal defects of femoral condyles, trochlea, talus, and capitellum (depending on joint and indication)

BMS (bone marrow stimulation) — definition and pooled success notes

DefinitionBone marrow stimulation (BMS; e.g., microfracture) is a less invasive cartilage repair technique that stimulates fibrocartilaginous repair by breaching subchondral bone to release marrow elements

Pooled outcomesPooled success rates vary by indication; for skeletally immature talar lesions pooled clinical success was 77% for BMS versus 44% for conservative treatment in one review

Comparative considerationsEvidence suggests microfracture may have higher early failure and poorer long-term durability compared with OAT and other restorative techniques for larger lesions

OATS / OAT / mosaicplasty — procedural summary for clarity

SummaryOAT/OATS/mosaicplasty are osteochondral autograft transfer procedures in which cylindrical plugs of bone and hyaline cartilage are harvested from a non-weight-bearing area and transplanted to focal defects to restore hyaline cartilage and subchondral bone

Procedure variantsTerminology overlaps across mosaicplasty (multiple small plugs), OATS (single larger plug), and OAT (generic term for autograft transfer)

Intended benefitDesigned to provide durable hyaline cartilage repair and improved function compared with cartilage repair techniques that produce fibrocartilage

Unified grading system (UGS) — grading system used in reviews

UGS definitionUnified grading system (UGS) is a grades 1–4 classification derived from existing systems to compare stable (grades 1–2) versus unstable (grades 3–4) capitellar OCD lesions across studies

Use in evidenceDeveloped in systematic review to allow comparison of outcomes by lesion grade and to guide treatment selection between non-operative and surgical options

Clinical relevanceUGS grades inform that non-operative treatment may suffice for low-grade (1–2) lesions while surgery is favored for unstable/high-grade (3–4) lesions

OCAMRISS — MRI scoring system for osteochondral allografts

DefinitionOCAMRISS (Osteochondral Allograft MRI Scoring System) is an MRI-based scoring system used to grade post-operative appearance of osteochondral allografts including bone and cartilage sub-scores

Use in studiesApplied in registry and cohort studies to quantify graft bone and cartilage integration and ancillary features on post-operative MRI

Reported metricsStudies report total OCAMRISS scores and sub-scores (bone, cartilage, ancillary) to monitor incorporation and graft status in follow-up imaging

Agili-C — cell-free biphasic aragonite-based scaffold

DefinitionAgili-C is a cell-free, off-the-shelf biphasic aragonite-based osteochondral scaffold implant intended for treatment of cartilage and osteochondral defects

Reported outcomesCase series report significant improvements in KOOS and IKDC scores and MRI defect filling up to ~78% surface coverage at 24 months; reported revision/failure rate ~9.3%

Evidence limitationsAvailable studies are level IV cohorts with limited long-term data and no matched controls; use outside studied defect sizes or advanced OA is not supported by current evidence