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CurrentAetnaPolicy 0661

Joint Resurfacing

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Defines Aetna's coverage criteria for joint resurfacing procedures (primarily metal-on-metal hip resurfacing) including medical necessity, contraindications, experimental/investigational procedures, and applicable billing/diagnosis codes; applies to Aetna members and treating providers.

Policy Summary

PayerAetna

PolicyJoint Resurfacing

Policy CodePolicy 0661

Change TypeNo material clinical or coverage changes indicated in this revision

Effective DateMay 2, 2003

Last ReviewNov 20, 2023

Next Review DateJul 11, 2024

Key ActionDocument at least 12 weeks of conservative (non-surgical) therapy in the medical record before consideration of resurfacing, or clearly justify why conservative therapy is inappropriate.

SourceLink

<65preferred patient age for hip resurfacing

>=12 wksconservative therapy duration

BMI>40morbid obesity contraindication

GFR<60renal insufficiency threshold

12,093AOANJRR primary resurfacing hips

97.6%5-yr survival (computer-assisted medial UKA)

Coverage Criteria for Joint Resurfacing

Medical necessity for metal-on-metal hip resurfacing

Covered when ALL of the following are met

Primary coverage criteria for metal-on-metal hip resurfacing: 1) Member has advanced joint disease with pain and functional disability that interferes with activities of daily living (ADLs) from osteoarthritis, avascular necrosis, or post‑traumatic arthritis of the hip; AND 2) Limited range of motion (ROM), antalgic gait, and hip joint pain on passive ROM on physical examination; AND 3) Radiographic or MRI evidence of severe osteoarthritis (2 or more of: subchondral cysts, subchondral sclerosis, periarticular osteophytes, joint subluxation, bone‑on‑bone articulation, or joint space narrowing) primarily affecting the femoral head, or osteonecrosis of the femoral head when detected early with <50% involvement; AND 4) Normal proximal femoral bone geometry and bone quality; AND 5) Member would otherwise require conventional primary total hip replacement but is likely to outlive the functional lifespan of a traditional prosthesis; AND 6) History of unsuccessful conservative therapy with at least 12 weeks of non‑surgical treatment documented (including anti‑inflammatories/analgesics; flexibility and muscle‑strengthening exercises; activity modification; supervised physical therapy; weight reduction as appropriate; assistive device use where appropriate; and therapeutic injections where appropriate).

Procedures considered experimental/investigational

Not covered / Experimental when any of the following apply

Policy Summary

PayerAetna

PolicyJoint Resurfacing

Policy CodePolicy 0661

Change TypeNo material clinical or coverage changes indicated in this revision

Effective DateMay 2, 2003

Last ReviewNov 20, 2023

Next Review DateJul 11, 2024

Key ActionDocument at least 12 weeks of conservative (non-surgical) therapy in the medical record before consideration of resurfacing, or clearly justify why conservative therapy is inappropriate.

SourceLink

On This Page

Experimental or investigational procedures: Computer‑assisted navigation for positioning during Birmingham Hip Resurfacing; facet joint resurfacing; knee resurfacing, partial knee resurfacing (e.g., Makoplasty), and isolated patellar resurfacing (e.g., UniCAP, HemiCAP); metal‑on‑metal hip resurfacing for developmental dysplasia of the hip; metal‑on‑polyethylene hip resurfacing implants; metal resurfacing inlay implant for osteochondral talar defects after failed prior surgery; metatarsophalangeal (MTP) toe joint resurfacing; radiocapitellar joint resurfacing/replacement; resurfacing capitate pyrocarbon implant for carpal/wrist injuries; and shoulder resurfacing (total and hemi‑resurfacing) for treatment of glenohumeral arthritis, humeral head fractures, osteochondral lesions, and other indications.

Contraindications / Not medically necessary

Not medically necessary when ANY listed contraindication is present

Contraindications: Active joint infection or unresolved systemic bacteremia; active skin infection or open wound in the planned surgical site (except recurrent cutaneous staphylococcal infections); allergy to metals used in resurfacing (e.g., cobalt, chromium, alumina); inactive/older individuals unlikely to require revisions of a traditional THR; morbid obesity (BMI > 40); inadequate bone stock to support the device; osteonecrosis with >50% femoral head involvement; severe anatomic deformity of the femoral head; skeletally immature patients; moderate‑to‑severe renal insufficiency (GFR < 60 mL/min/1.73 m2); multiple femoral neck cysts >1 cm; vascular insufficiency, muscular atrophy, or neuromuscular disease compromising implant stability or recovery; immunosuppression or high‑dose corticosteroid therapy; females of child‑bearing potential (due to unknown fetal effects of metal ion release).

Coverage when patient selection and implant/surgeon factors are met

Covered when ALL of the following are met:

Selection criteria for resurfacing: Patient is a younger, active individual for whom bone preservation is a priority and who is an appropriate surgical candidate; AND the procedure will be performed by an experienced surgeon using validated implant(s).

Comparative evidence and justification: Documentation justifies choice of resurfacing over total hip arthroplasty (THA) for this patient (for example: anticipated longevity of patient relative to prosthesis lifespan, desire to preserve femoral bone stock, or activity expectations) and cites available randomized/registry data or rationale given uncertainty of long‑term durability.

Device-specific risk restrictions

Not covered / restricted considerations:

Device‑specific high‑risk implants or scenarios: Use of implants with documented high early failure or recall history (e.g., DePuy ASR systems) or presentation with adverse local tissue reactions (ALTR) or very high metal ion levels should prompt close evaluation and may restrict coverage for continued use or selection of that implant given documented higher revision rates and complications.

High ALTR prevalence and elevated revision rates reported for ASR systems; high blood metal ion levels (>7 μg/L cobalt or chromium) associated with higher failure/ALTR.

Contexts and evidence summary for resurfacing procedures

Summary of contexts where focal or resurfacing procedures may be appropriate and situations associated with poor outcomes:

Shoulder humeral head resurfacing — favorable scenario: Reserved for concentric gleno‑humeral osteoarthritis without glenoid erosions or rotator cuff damage; cases with glenoid erosion or rotator cuff tear are associated with high failure and revision rates.

Single‑center series reported high failure related to glenoid wear/rotator cuff impairment leading authors to reserve procedure for concentric OA without these features.

Knee focal resurfacing — typical candidate attributes: Patients aged approximately 40–60 years with early‑stage osteoarthritis confined to a single compartment, physically active or overweight individuals; device examples include HemiCAP and UniCAP. Evidence is limited to small studies without internal comparison groups.

Robotic‑assisted UKA considerations: Robotic assistance (e.g., MAKO/MAKOplasty) improves radiographic alignment and reduces outliers but evidence is inconsistent regarding improved long‑term clinical outcomes or implant survivorship; robotic procedures may increase operative time and cost and should be considered when expected benefits are documented.

Patellar resurfacing in TKA: Randomized trials and reviews show mixed results for routine patellar resurfacing with modern implants; decisions should be individualized and consider implant design and surgeon judgment.

Evidence summaries (no coverage criteria in this segment)

Evidence summary nodes: Multiple small case series, cohort studies, randomized trials, and meta‑analyses report improved radiographic alignment and intra‑operative accuracy with computer‑assisted and robotic techniques and varied short‑term clinical outcomes; however, long‑term survivorship and functional benefit remain uncertain and many studies are limited by small size, single‑surgeon series, or short follow‑up.

Evidence summary (no coverage rule stated)

Evidence-based findings summarized (no explicit coverage criteria present in this excerpt).

Radiographic and intra‑operative accuracy advantages: Robotic and computer‑assisted techniques improve mechanical alignment, reduce alignment outliers, predict implant size accurately, and assist intra‑operative gap balancing; thresholds used in studies include post‑operative neutral alignment of 0° ± 3° and balanced gap definition of medial‑lateral gap difference within 2 mm.

Coverage considerations / medical necessity

Coverage considerations when determining medical necessity of resurfacing procedures:

RA‑TKA coverage considerations: Robotic‑assisted TKA (RA‑TKA) may be considered when standard indications for TKA are met and when documented goals include improved component positioning or other expected short‑term benefits; available evidence notes reduced length of stay and opioid use but is limited by short follow‑up, single‑surgeon series, and lack of randomized trials.

Partial femoral condyle focal resurfacing (HemiCAP/UniCAP): Focal femoral condyle resurfacing has demonstrated unacceptable mid‑ to long‑term revision rates in some series (eg, UniCAP revision 53.66% at 5–7 years; registry cumulative revision rates ~40.6% at 10 years for HemiCAP); use should be limited, justified in documentation, and avoided for larger defects (>4 cm2) when evidence shows high revision risk.

Resurfacing capitate pyrocarbon implant (RCPI): RCPI combined with proximal row carpectomy may be considered as a salvage alternative in selected patients with advanced wrist OA or specific carpal injuries when prior treatments have failed; evidence is limited and small with variable follow‑up, and documentation of prior therapies and informed consent about limited long‑term data is required.

This policy addresses joint resurfacing procedures across multiple anatomic sites. Covered resurfacing approaches referenced in the document include hip resurfacing (metal-on-metal), and examples of focal resurfacing devices and systems for the knee such as HemiCAP and UniCAP. Other resurfacing contexts discussed include shoulder (humeral head) resurfacing, patellar/partial knee resurfacing, wrist»resurfacing capitate pyrocarbon implant (RCPI), metatarsophalangeal (MTP) joint resurfacing, radiocapitellar resurfacing, and facet joint resurfacing — though many of these are described as investigational or having limited evidence. Robotic-assisted unicompartmental knee techniques (e.g., MAKO/MAKOplasty) and computer-assisted navigation are also discussed as resurfacing-related technologies used to assist implant positioning.

The policy highlights specific implants with documented early failure or recall histories that have been associated with high revision rates and adverse local tissue reactions, for example the DePuy ASR systems. Systematic reviews and single-center series report high ALTR prevalence (mean ~33.5%) and mean revision rates in the mid-term (ASR HRA ~13.8% at 4–7 years), and single-center ASR XL series reported a 5-year revision of 34.4%; such device-specific poor outcomes warrant close evaluation and often restrict use.

Humeral head (shoulder) resurfacing is described as a bone-preserving option reserved for selected patients. It is most appropriate for concentric gleno-humeral osteoarthritis with intact rotator cuff and without glenoid erosions, and is considered mainly for younger patients where bone preservation is a priority. Evidence is limited to observational series with short- to mid-term follow-up and documentation should justify selection over standard shoulder arthroplasty alternatives.

The policy enumerates contraindications and pre-operative factors associated with poor outcomes after humeral head resurfacing. Cases with glenoid erosion or rotator cuff tear had significantly higher failure and revision rates in series cited; therefore humeral resurfacing is generally not appropriate when these findings are present. These site-specific concerns align with the broader contraindications for resurfacing (e.g., inadequate bone stock, active infection, morbid obesity, significant comorbidity or skeletal immaturity).

Limitations of the evidence are emphasized throughout: many studies are small, single-center or single-surgeon series, have short to mid-term follow-up, and heterogeneous implants and techniques. These limitations reduce certainty about long-term implant survivorship and make it difficult to separate technique-related from device-related effects; the policy therefore cautions about broader adoption until longer-term, comparative data are available.

The metal talar inlay technique for osteochondral talar defects requires a medial malleolar osteotomy to access the lesion and therefore is not applicable to lateral talar dome lesions.

Within the excerpted material there are no explicit clinical exclusion criteria specified for robotic-assisted procedures; the document discusses evidence gaps, planning workflows (eg, CT-based templating), and documentation considerations but does not list robotic procedures as clinically excluded in the provided text.

Patients who meet the explicit contraindications for metal-on-metal hip resurfacing are excluded from consideration. This includes females of child-bearing potential, individuals who are immunosuppressed or on high-dose corticosteroids, those who are severely overweight (BMI > 40), skeletally immature patients, those with inadequate bone stock, active infection or sepsis, moderate-to-severe renal insufficiency (GFR < 60 mL/min/1.73 m2), and known or suspected metal sensitivity; presence of any listed contraindication renders hip resurfacing not medically necessary.

This Clinical Policy Bulletin is intended to assist in administering plan benefits and provide clinical guidance. It does not constitute a contract, guarantee coverage, or replace plan-specific provisions; coverage determinations remain subject to the member's plan benefits and applicable contractual terms.

When any of the listed contraindications to metal-on-metal hip resurfacing are present, the policy states that hip resurfacing is not medically necessary. The contraindications include active joint or systemic infection, metal allergy, morbid obesity (BMI > 40), inadequate bone stock, osteonecrosis involving >50% of the femoral head, severe anatomic deformity, skeletal immaturity, renal insufficiency (GFR < 60), multiple large femoral neck cysts, significant neuromuscular or vascular compromise, immunosuppression, and females of child-bearing potential.

The policy reiterates that appropriate patient selection and device/surgeon factors are critical for favorable outcomes: resurfacing may be considered for younger, active patients with preserved bone quality who are expected to outlive a conventional THA prosthesis, and the procedure should be performed by experienced surgeons using validated implants. Documentation is required to justify selection over THA, and to support implant choice and surgeon experience when submitting for authorization.

Biologic glenoid resurfacing techniques for the shoulder have produced inconsistent results and relatively high complication rates in some series; given unreliable outcomes and observed glenoid erosion in follow-up, established alternatives such as total shoulder arthroplasty should be considered and biologic resurfacing reserved for selected cases with supporting evidence and clear documentation.

Robotic-assisted partial knee resurfacing systems (eg, MAKO/MAKOplasty) and similar technologies show improved radiographic implant positioning accuracy versus conventional techniques but the clinical evidence for improved long-term patient outcomes or implant survivorship is insufficient. The policy characterizes these procedures as having insufficient published clinical evidence to support routine coverage and recommends documentation and justification when used.

Evidence regarding routine patellar resurfacing in total knee arthroplasty is conflicting. Multiple meta-analyses and randomized trials report mixed results with some showing no clear superiority of resurfacing and others showing differences in specific outcomes; therefore the policy states that results are inconsistent and clinical decisions should be individualized based on implant design and patient factors.

Within the provided excerpts the document does not present an explicit list of procedures or uses labeled as universally 'not medically necessary' beyond the contraindications and investigational lists; many determinations are framed as investigational, limited evidence, or not supported for particular devices or patient subgroups rather than broad categorical exclusions.

The UniCAP system used for focal femoral condyle defects shows very high revision rates when applied to larger defects. Specifically, use of UniCAP for defects > 4 cm2 was associated with an unacceptably high revision rate (~53.66% at 5–7 years) and is not supported for such defect sizes.

Applicable Billing and Diagnosis Codes

CPT/HCPCS codes covered if selection criteria are metmixedCovered

27125	Hemiarthroplasty, hip, partial (e.g., femoral stem prosthesis, bipolar arthroplasty) [per AAOS for a femoral head resurfacing procedure, when only the head of the femur is replaced (a femoral component hemiarthroplasty)]
27130	Arthroplasty, acetabular and proximal femoral prosthetic replacement (total hip arthroplasty), with or without autograft or allograft [Hip resurfacing for arthroplasty]
27033	Arthrotomy hip, including exploration or removal of loose or foreign body.
27122	Acetabuloplasty; resection, femoral head (e.g., Girdlestone procedure).
27132	Conversion of previous hip surgery to total hip arthroplasty, with or without autograft or allograft.
27360	Partial excision (craterization, saucerization, or diaphysectomy) bone, femur, proximal tibia and/or fibula (e.g., osteomyelitis or bone abscess).
S2118	Metal-on-metal total hip resurfacing, including acetabular and femoral components.

ICD-10 codes covered if selection criteria are metICD-10Covered

M16.0 - M16.12	Primary osteoarthritis, left hip (and related primary osteoarthritis codes listed)
M16.2 - M16.7	Secondary osteoarthritis of hip
M16.9	Osteoarthritis of hip, unspecified
M87.051 - M87.059	Idiopathic aseptic necrosis, femur [avascular necrosis of the hip joint]
M87.150 - M87.159	Osteonecrosis due to drugs, pelvis and femur [avascular necrosis of the hip joint]
M87.251 - M87.256	Osteonecrosis due to previous trauma, pelvis and femur
M87.350 - M87.353	Other secondary osteonecrosis, pelvis and femur
M87.850 - M87.859	Other osteonecrosis, pelvis and femur
M90.551 - M90.559	Osteonecrosis in diseases classified elsewhere, thigh

ICD-10/CPT codes not covered or contraindicated for CPB indications (not all-inclusive)mixedNot Covered

Q65.00 - Q65.6	Congenital dislocation of hip [developmental dysplasia]
A41.01 - A41.9	Other sepsis
E66.01	Morbid (severe) obesity due to excess calories [BMI greater than 40]
Z68.41 - Z68.45	Body mass index (BMI) 40 and over, adult
23470	Arthroplasty, glenohumeral joint, hemiarthroplasty (CPT codes not covered for shoulder resurfacing indications)
23472	Total shoulder (glenoid and proximal humeral replacement) (CPT codes not covered for shoulder resurfacing indications)

Examples of knee resurfacing systems (device names)mixed

HemiCAP	HemiCAP patello-femoral resurfacing prosthesis (device name)
UniCAP	UniCAP compartmental resurfacing implant system (device name)

Robotic systems referencedmixed

MAKO	MAKO Tactile Guidance System / MAKOplasty (robotic system/device name)

Imaging/templating referencedmixed

No codes listed

Conservative therapy duration (inv-32)

Conservative therapy durationAt least 12 weeks of non-surgical treatment documented (anti-inflammatories/analgesics; flexibility and strengthening exercises; activity modification; supervised physical therapy; weight reduction; assistive devices as appropriate; therapeutic injections as appropriate)

If not attemptedMedical record must document why conservative therapy is inappropriate

Documentation requirementHistory of unsuccessful conservative therapy must be clearly addressed in the medical record

Femoral head osteonecrosis (inv-33)

Femoral head osteonecrosis involvement thresholdCoverage only when osteonecrosis involves less than 50% of the femoral head

Contraindication thresholdOsteonecrosis with more than 50% femoral head involvement is a contraindication to hip resurfacing

Imaging supportRadiographic or MRI evidence required to assess percent involvement

Renal function threshold (inv-34)

Renal function thresholdGFR >= 60 mL/min/1.73 m2 required for consideration; GFR < 60 is a contraindication

Contraindication categoryModerate-to-severe renal insufficiency (GFR < 60) listed among absolute contraindications

DocumentationRenal function should be addressed in medical record when assessing candidacy

Metal ion level risk threshold (inv-35)

Metal ion risk thresholdSerum cobalt or chromium greater than 7 µg/L associated with higher failure rates and ALTR

Clinical implicationHigh blood metal ion levels are a risk factor for ALTR and device failure and should prompt close evaluation

Device-specific noteFindings reported specifically in ASR system literature where ALTR prevalence and revision rates were high

Severe coronal deformity threshold (inv-36)

Severe coronal deformity threshold>= 7° coronal deformity defined as severe

Correction capabilityRobotic-assisted techniques reported correcting deformities <7° to neutral and many >=7° toward neutral, but severe deformity (>=7°) is considered notable

Clinical relevanceDegree of deformity affects candidacy and expected intra-operative correction

Post-operative neutral alignment (inv-37)

Post-operative neutral alignment windowNeutral alignment defined as 0° ± 3° (post-operative coronal alignment)

Outlier definitionMechanical axis outliers defined as greater than ±3° from neutral

Outcome relevanceRobotic-assisted techniques report fewer alignment outliers versus conventional methods

Balanced gap threshold (inv-38)

Balanced gap thresholdMedial-to-lateral flexion (and extension) gap difference within 2 mm is considered balanced after bone cuts

Intra-operative measurementRobotic software reported high proportions achieving post–bone cut gap differences within ±2 mm

Clinical implicationGap balance is used to assess soft-tissue/implant balance and may influence outcomes

Prior Authorization, Documentation, and Provider Responsibilities

Note

Provider action: None explicitly specified

No explicit provider action is specified in this module. This section primarily provides background, evidence review, and references rather than prescriptive administrative requirements.

Note

Provider action: This module contains bibliographic references

This module contains bibliographic references that support the clinical background and evidence summaries. Providers should consult the cited literature for detailed study methods, outcomes, and device-specific safety data when preparing documentation or prior authorization requests.

Documentation Required

Provider action: Suggested outcome and imaging documentation

Suggested outcome and imaging documentation should be included when submitting cases for consideration or for clinical records. Examples include validated patient-reported outcome measures, objective functional scores, and radiographic/advanced imaging evidence of disease.

Outcome measures: WOMAC, KOOS, UCLA activity score, Constant-Murley, KSS, DASH, FJS, PROMs where applicable
Imaging: weight-bearing radiographs demonstrating osteoarthritic changes (joint space narrowing, osteophytes, subchondral sclerosis/cysts, bone-on-bone), pre-operative CT for 3D templating when used for RA-TKA/RA-TKA planning, MRI when assessing osteonecrosis or soft-tissue pathology
Clinical findings: documented pain and functional disability affecting ADLs, limited ROM, antalgic gait, and prior conservative therapy details

Documentation Required

Provider action: Pre-operative CT planning documentation

When pre-operative CT-based planning is used (commonly with robotic-assisted TKA/TKA platforms), document the CT and the surgeon's recorded pre-operative plan, including predicted implant sizes and planned alignment. Retain comparison of planned versus implanted component sizes in operative records.

Include the dated pre-operative CT scan in the record and note that CT-based 3D templating was performed
Record surgeon's planned implant sizes and predicted component positions pre-operatively and document final intra-operative implants used
If robotic workflow is used, document device platform, software version, and any device-specific planning outputs relied upon

Documentation Required

Provider action: Provider responsibility and document status

Provider responsibilities and documentation status: treating providers are responsible for medical advice and treatment decisions. Ensure the medical record contains indications, prior conservative therapy, comorbidities/contraindications, device/implant details, and follow-up/surveillance plans.

Document rationale for selecting resurfacing or device-based approaches over standard alternatives (e.g., THA, UKA) when applicable
Record contraindications assessed (infection status, metal allergy, BMI, bone stock, renal function, reproductive considerations) and any exemptions to conservative therapy with justification
Maintain follow-up plan including clinical surveillance and, where applicable, serum metal ion monitoring and imaging follow-up

Note

Provider action: No step therapy requirements described

No step therapy requirements are described in this section. There are no explicit step therapy, prior authorization sequencing, or mandated trial hierarchies detailed in the provided excerpts.

Background and Evidence Context

Hip resurfacing arthroplasty (HRA) is described as a bone-preserving alternative to total hip arthroplasty (THA) that caps rather than removes the femoral head, intended primarily for younger, active patients with good proximal femoral bone quality who may outlive a traditional THA prosthesis. Potential advantages include femoral bone preservation, a larger femoral head (lower dislocation risk), less thigh pain in some reports, and the option to convert to THA if necessary; however, most evidence derives from short- to mid-term observational series and long-term randomized comparative data are limited.

Contexts and evidence summary for resurfacing procedures

Summary of contexts where focal or resurfacing procedures may be appropriate and situations associated with poor outcomes:

Shoulder humeral head resurfacing — favorable scenario: Reserved for concentric gleno‑humeral osteoarthritis without glenoid erosions or rotator cuff damage; cases with glenoid wear or rotator cuff tear are associated with high failure and revision rates.

Knee focal resurfacing — typical candidate attributes: Patients aged ~40–60 years with early‑stage OA confined to one compartment, physically active or overweight; device examples include HemiCAP and UniCAP. Evidence is limited and follow‑up short, with notable mid‑term revision rates for some devices.

Robotic‑assisted UKA considerations: Robotic‑assisted UKA shows improved alignment accuracy but insufficient evidence of long‑term clinical outcome benefit; routine use is not supported without justification due to added cost and operative time.

Patellar resurfacing in TKA: Evidence from numerous RCTs and meta‑analyses is mixed; routine patellar resurfacing is not uniformly supported and should be individualized based on implant design and patient factors.

When determining medical necessity for resurfacing procedures the policy emphasizes contextual evidence considerations: require documentation of advanced joint disease with functional limitation, failure of at least 12 weeks of conservative therapy, preserved proximal femoral bone geometry, and less than 50% femoral head osteonecrosis when present. The policy also stresses device-specific safety signals (eg, high metal ion levels > 7 µg/L associated with adverse local tissue reaction) and trial/registry data showing variable mid-term revision rates, underscoring the need for careful patient, implant, and surgeon selection.

Definitions and Terminology

Partial (hemi) HRA (inv-84)

Partial (hemi) HRARemoval and resurfacing of only the femoral head surface with a metal shell; acetabular socket left intact

Indication contextOften considered for younger, active patients with viable proximal femoral bone who may outlive a THR prosthesis

Device examplesFDA-approved systems include Birmingham Hip Resurfacing, Conserve Plus, ReCAP HA Press-Fit, Cormet

Total HRA (inv-85)

Total HRAResurfacing that replaces both the femoral head surface with a metal shell and resurfaces the acetabular socket

Procedure descriptionMetal shell placed over femoral head and damaged surface of hip socket also resurfaced

Comparative roleAn alternative to THR in selected younger patients when criteria are met

Surface replacement arthroplasty / Hip resurfacing (inv-86)

Surface replacement arthroplasty (SRA) / Hip resurfacing (HR)Procedure preserving femoral head and neck, replacing only joint surfaces with small-volume implants without opening the medullary canal (typically metal-on-metal bearings)

AdvantagesConserves femoral bone, may reduce thigh pain, and allows conversion to THR if needed

Evidence noteLong-term comparative RCT data are limited; mid-term outcomes comparable to THA in some series

Adverse local tissue reaction (ALTR) (inv-87)

Adverse local tissue reaction (ALTR)Local soft-tissue reaction associated with metal debris/ions from metal-on-metal bearings, linked to pain, tissue necrosis, and higher revision rates

AssociationHigher blood metal ion levels (>7 µg/L Co or Cr) associated with increased ALTR prevalence

Clinical consequenceALTR prevalence and revision risk warrant close clinical surveillance and laboratory monitoring

Hip resurfacing (HR) (inv-88)

Hip resurfacing (HR)Bone-preserving alternative to THA that caps the femoral head to preserve femoral bone stock and biomechanics; intended for younger active patients

Clinical contextMay reduce dislocation risk and allow conversion to THA if needed

EvidenceRandomized and registry data provide mid-term outcomes; long-term durability remains under investigation

Shoulder resurfacing (inv-89)

Shoulder resurfacingReplacement of only the diseased surface of the humeral head (hemi-resurfacing) or combined with glenoid replacement (total shoulder resurfacing) using metallic caps or biologic interposition to preserve proximal humeral bone stock

Device examplesCopeland resurfacing head; DePuy Global C.A.P.; CTA; Axiom; HemiCAP

Appropriate scenarioReserved for younger, active adults with concentric gleno-humeral OA without glenoid erosions or irreparable rotator cuff damage

Knee focal resurfacing (inv-90)

Knee focal resurfacingImplantation of defect-sized components matched to the individual joint surface (e.g., HemiCAP, UniCAP) as an alternative to total knee replacement for focal or compartmental disease

Typical candidatesPatients aged ~40–60 with early-stage OA confined to one compartment, physically active or overweight

Evidence limitationAvailable evidence limited to small studies without internal comparison groups

Focal knee resurfacing (inv-91)

Focal knee resurfacing (alternate)Defect-matched implantation (HemiCAP, UniCAP) to treat localized cartilage lesions without major bone resection

Device exampleUniCAP Bipolar Knee Resurfacing System uses intraoperative 3D joint surface mapping

RecommendationWork Loss Data Institute listed focal joint resurfacing as considered but not recommended due to limited evidence

Robotic-assisted UKA (MAKO) (inv-92)

Robotic-assisted UKA (MAKO/MAKOplasty)Use of robotic systems (e.g., MAKO TGS/MAKOplasty) to assist bone preparation and implant positioning in unicompartmental knee arthroplasty

Intended benefitAims to increase accuracy, reproducibility, and optimize component position, though clinical benefit and long-term survivorship remain unproven

Evidence cautionCADTH and other assessments found insufficient evidence to justify routine use; higher operative time and costs reported in some studies

MTP joint resurfacing (inv-93)

MTP joint resurfacingSurgical resurfacing of the metatarsal head to restore a contoured cap matching cartilage surface (e.g., CAP, OsteoMed systems)

IndicationsUsed for hallux rigidus and post-traumatic arthritis of the first MTP joint

Regulatory examplesFDA 510(k) summaries exist for OsteoMed and CAP systems

Facet joint resurfacing (FENIX) (inv-94)

Facet joint resurfacing (FENIX)Implantation of a bilaterally implanted device to address single-segment lumbar facet joint OA aiming to preserve motion and reduce pain (feasibility data available)

EvidenceFeasibility study (n=8) reported pain relief and preserved mobility at 24 months in most patients

RecommendationFurther studies needed to validate broader use

Radiocapitellar resurfacing (inv-95)

Radiocapitellar resurfacing (LRE system)Unicompartmental resurfacing/replacement of the radiocapitellar joint to treat isolated radiocapitellar OA while preserving radial head and annular ligament anatomy

Clinical evidenceLimited case reports/series; short-term favorable outcomes reported but further studies needed

Surgical goalRestore stability and avoid altering unaffected ulno-humeral joint

CAS / RA-TKA definition (inv-96)

Computer-assisted navigation (CAS) / RA-TKASurgical technologies to assist intra-operative component selection and positioning to improve alignment accuracy and minimize bone resection

Reported benefitsReduced alignment outliers, improved gap balancing, and more accurate implant sizing/prediction in studies

Evidence gapsClinical outcome and long-term survivorship benefits remain uncertain; many studies are small or single-surgeon

Neutral alignment definition (inv-97)

Neutral alignment (definition)Post-operative coronal alignment defined as 0° ± 3°

Clinical useUsed as outcome benchmark for alignment accuracy assessments in TKA/UKA studies

Outlier thresholdDeviation greater than ±3° considered an outlier

Balanced knee (post-bone cut) (inv-98)

Balanced knee (post-bone cut)Medial and lateral flexion gap difference within 2 mm is considered balanced after bone cuts

Measurement contextRobotic cohorts report high percentages achieving post–bone cut gap differences within ±2 mm

RelevanceBalance used to assess soft-tissue symmetry and influence clinical function

Learning curve (RA-TKA) (inv-99)

Learning curve (RA-TKA)Proficiency inflection for operative time ranges from approximately 7 to 11 cases (CUSUM analyses)

Early casesEarly robotic cases may have longer operative times that improve with experience

ImplicationLearning-curve considerations should be documented when assessing outcomes or planning adoption

CT-based 3D planning (inv-100)

CT-based 3D planningPre-operative CT imaging used to create a 3D surgical plan that predicts implant sizing and guides robotic-assisted bone preparation

Predictive accuracyStudies report CT-based plans within 1 implant size of final components in 100% of cases and exact match ~80%

DocumentationSurgeons recorded pre-operative CT plans and final implants for comparison to support planning accuracy

Conservative therapy definition (inv-101)

Conservative therapy (definition)Non-surgical medical management

Components (per policy)Anti-inflammatories/analgesics; flexibility and strengthening exercises; activity modification; supervised physical therapy; weight reduction; assistive devices; therapeutic injections

Intended roleShould generally be attempted and documented prior to consideration of resurfacing procedures unless contraindicated

FDA summaries / 510(k) / PMA (inv-102)

FDA summaries / 510(k) / PMAFDA 510(k) and PMA summaries and effectiveness data relate to regulatory clearances and approvals for resurfacing implants (examples: BHR PMA, ReCap 510(k))

Examples citedBirmingham Hip Resurfacing PMA; ReCap HA press-fit 510(k); OsteoMed and CAP 510(k) for MTP devices

Use in policyRegulatory summaries referenced to contextualize device approvals and available evidence

Robotic-assisted arthroplasty literature (inv-103)

Robotic-assisted arthroplasty literatureLiterature pertains to techniques for knee resurfacing and component placement accuracy; includes RCTs, cohort studies, systematic reviews and meta-analyses

Reported outcomesStudies report improved alignment accuracy, reduced outliers, and mixed short-term functional benefits; learning-curve and cost data discussed

Evidence limitationsMany studies are small, single-surgeon, or short-term; long-term survivorship and clinical benefit remain uncertain

Clinical Policy Bulletin (inv-104)

Clinical Policy Bulletin (definition)Document developed by Aetna to assist in administering plan benefits; not an offer of coverage or medical advice

Contractual noteContains a partial, general description of plan benefits and does not constitute a contract; specific plan provisions govern coverage

Provider responsibilityTreating providers are responsible for medical advice and treatment; CPB may be updated

Joint Resurfacing

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Coverage Criteria for Joint Resurfacing

Applicable Billing and Diagnosis Codes

Prior Authorization, Documentation, and Provider Responsibilities

Background and Evidence Context

Definitions and Terminology

Policy Dates and Revision History