I. Disclaimer

This document is intended to be used as a reference for non-VA providers and not intended to replace clinical judgment when determining care pathways. These guidelines do not guarantee benefits or constitute medical advice.

II. Clinical Determinations and Indications

1. Indications for Autologous Chondrocyte Implantation
   Although autologous chondrocyte implantation (ACI) is generally considered investigational and experimental for the treatment of symptomatic articular cartilage lesions of the knee joint, it may be considered medically necessary/covered in limited circumstances when ALL the following evidence-based clinical criteria are met:
   • Veteran is 18-55 years old 
   • Presence of grade III or grade IV full thickness articular cartilage loss on a load-bearing surface of the medial femoral condyle, lateral femoral condyle, femoral trochlea, or patella 
   • Minimal to absent degenerative changes of the surrounding articular cartilage (Outerbridge grade II or less) and normal appearance of hyaline cartilage at the border of the defect 
   • The focal chondral defect size is between 1.5-10 cm² 
   • Defects under 4 cm² should have been previously managed with marrow-stimulating techniques prior to ACI 
   • Inadequate response to conservative therapy and/or prior arthroscopic or other surgical repair procedure (e.g., debridement, microfracture, subchondral drilling, abrasion chondroplasty, or osteochondral allograft/autograft) 
   • The knee must be stable and aligned (a corrective procedure in combination with or prior to ACI may be necessary to ensure stability, alignment, and normal weight distribution within the joint) 
   • Symptomatic lesion, defined as disabling knee pain, swelling, or catching/locking due to focal chondral and osteochondral defects that significantly limits activities of daily living 
   • Focal articular cartilage defect down to but not through the subchondral bone on a load-bearing surface of the medial femoral condyle, lateral femoral condyle, femoral trochlea, or patella 

Note: Veteran’s willingness and ability to consent for surgery and fully participate in a prescribed postoperative rehabilitation program is necessary to ensure optimal outcome.

2. Limitations/Exclusions
   Autologous chondrocyte implantation is not indicated and therefore considered not medically necessary and not covered if any of the following are applicable:
   • Uncorrected malalignment and instability of the affected knee joint, unless being performed at the time of the ACI
   • Current infection at any of the operative sites
   • Allergy or sensitivities to gentamicin, other aminoglycosides, or products of porcine or bovine origin
   • Presence of kissing lesions (articular cartilage defect on the femur and tibia in the same compartment of the knee)
   • History of previous cancer in the bones, cartilage, fat, or muscle of the treated limb
   • Knee joint with more than 50% loss of cartilage thickness (mild to moderate arthritis)
   • Poorly controlled diabetes, as defined as an HbA1c of greater than 7%
   • Deficient soft-tissue coverage
   • Body mass index (BMI) greater than or equal to 35 kg/m

Conditions/indications for which ACI is not medically necessary and not covered include, but are not limited to, the following:

• Degenerative arthritis 
• Talar (ankle) lesions, or lesions of other joints (e.g., hip and shoulder) 
• Cartilaginous defect associated with osteoarthritis, rheumatoid arthritis, or inflammatory disease  

For all other conditions or indications not listed in section II.a. of this document, ACI is considered not medically necessary and not covered due to insufficient evidence of efficacy and safety.

3. Description of Treatment

Autologous chondrocyte implantation is a form of tissue engineering where the patient’s cartilage cells are harvested and proliferated to repair defects in the articular cartilage of the same patient. Autologous chondrocyte implantation is designed to address areas of damaged or missing cartilage, which may cause pain, stiffness, and limited joint mobility. It is considered an appropriate treatment option for select young patients with single or multiple focal cartilage lesions who have not responded to conservative therapies.

Autologous chondrocyte implantation includes different techniques for use of expanded autologous derived chondrocytes which may include matrices to induce expansion. Matrix-induced autologous chondrocyte implantation (MACI) is an approved Food and Drug Administration (FDA) therapy. Carticel is a different FDA-approved process for in-vitro expansion of autologous chondrocytes. Both products should be used in alignment with FDA approvals.

Autologous chondrocyte implantation is a two-stage surgical procedure. In the first procedure, a region of healthy articular cartilage is identified and biopsied through an arthroscopic procedure from a non-weight-bearing area of the patient’s knee joint. The harvested cartilage tissue contains chondrocytes, which are specialized cells responsible for cartilage production and maintenance. The extracted cartilage sample is sent to a specialized laboratory where the chondrocytes are minced, enzymatically digested, and separated by filtration. Culturing chondrocytes increases the number of viable chondrocytes. This process typically takes several weeks.

The second procedure is performed when the desired level of chondrocytes is obtained. During this procedure, an arthrotomy (open joint surgery) is performed, and the damaged cartilage area is prepared. A biocompatible scaffold, often made of collagen or other suitable materials may be placed over the cartilage defect, or the chondrocytes may be covered with a periosteal flap at the site of the defect. The cultured chondrocytes are carefully seeded in the defect area. The chondrocytes are expected to adhere to a scaffold if used and gradually fill the cartilage defect over time. The surgical site is closed, and the patient undergoes a rehabilitation program to protect the newly implanted cells and promote proper cartilage healing.

Postoperative rehabilitation compliance is important for a successful outcome. Weight-bearing and physical activity are typically restricted initially, gradually increasing as the cartilage heals. Physical therapy emphasizing range-of-motion of the knee and strengthening activities is prescribed. Continuous passive motion (CPM) machines to improve the graft’s success may be recommended. Research suggests an average time for return to full activity following ACI ranges from 12 to 24 months.

III. Background and Supporting Information

The following information is for reference purposes only in accordance with the medical benefits package outlined in 38 C.F.R. § 17.38 (b). Each subsection supports VA’s determinations for medical necessity and alignment with generally accepted standards of medical practice.

1. Background Information

   Articular cartilage within joints may be damaged by either acute injuries or normal wear and tear. Signs and symptoms include pain, swelling, catching, or locking, loss of function, restricted mobility, and disability. These manifestations can severely impair activities of daily living and adversely affect quality of life. Long-standing severe damage to the articular cartilage can lead to debilitating osteoarthritis, which may require surgical treatment if non-surgical approaches are insufficient.

   Conventional treatment options for damaged articular cartilage of the knee joint include debridement, subchondral drilling, microfracture, and abrasion chondroplasty. Autologous chondrocyte implantation (ACI) falls within the group of therapies that aim to induce chondrogenesis (growth of chondrocytes) within transplanted tissue or cells for the treatment of cartilage defects in the knee. An advantage of ACI is the reduced risk of graft rejection by the patient’s body since the cartilage cells are taken from the patient’s own body. Studies have shown that patients who undergo ACI for articular cartilage damage of the knee experience improvements in pain, function, activity level, and quality of life.

2. Research, Clinical Trials, and Evidence Summaries

   There is limited evidence assessing the efficacy of ACI compared to standard treatments. Available studies report that patients treated with ACI achieved mixed outcomes. Studies have not been able to determine if favorable outcomes are a direct result of ACI. Studies were also unable to determine if ACI was comparatively better than, the same as, or worse than the outcomes from other treatments. Further, ACI techniques have continued to evolve, so long-term trial data on ACI reflects forms and techniques that are now superseded, such as with matrix-induced autologous chondrocyte implantation (MACI), the newest generation of ACI.

   Na et al. (2019) conducted a systematic review to evaluate the clinical efficacy of ACI and microfracture at a minimum mean 5-year follow-up. The research team utilized MEDLINE, Embase, and Cochrane Library databases to search for literature through August 2018. Five comparative studies (three randomized controlled trials and two prospective cohort studies) met eligibility criteria and were utilized in the review. Authors found that clinical outcomes of articular cartilage lesions of the knee treated with modified versions of ACI (ACI with a modified collagen membrane [ACI-C] or matrix-applied chondrocyte implantation [MACI]) can significantly improve patient outcomes at the midterm follow-up of five years compared to those treated with microfracture. Improved clinical results (with significant differences) were found with ACI versus microfracture as determined by the Knee Injury and Osteoarthritic Outcome Score (KOOS), activities of daily living assessment, Tegner Activity Scale score, and the International Knee Documentation Committee (IKDC) objective and subjective scores.

   Minas et al. (2014) conducted a study to evaluate the survivorship of ACI grafts, long term functional outcomes, and analyze potential predictors for failure. Two hundred ten patients, with symptomatic cartilage defects in all compartments of the knee unresponsive to nonoperative measures, were followed for more than 10 years after ACI. Studies showed that ACI provided durable outcomes with a survivorship of 71% at 10 years, and improved function in 75% of patients with symptomatic cartilage defects of the knee at a minimum of 10 years after surgery. Fifty-three patients (25%) had at least one failed ACI graft. A history of prior marrow stimulation as well as the treatment of very large defects were associated with an increased risk of failure. Authors concluded that ACI demonstrated favorable results in over 75% of patients up to 10 years after surgery.

   Saris et al. (2014) conducted a two-year prospective, multicenter, randomized, open-label, parallel-group study to compare the efficacy and safety of MACI versus microfracture (MFX) for treating patients with symptomatic cartilage defects of the knee. The study utilized the KOOS for pain and function to assess 144 patients from baseline through two years. The study found that MACI was clinically and statistically more efficacious than MFX for the treatment of symptomatic cartilage knee defects. In addition, the study showed that MACI had a similar safety profile compared to MFX. The findings from this study led the FDA in 2016 to approve MACI for the repair of symptomatic single or multiple full-thickness cartilage defects of the knee.

   Nawaz et al. (2014) studied patients who underwent ACI for osteochondral defects of the knee from 1998-2008. The purpose was to evaluate the functional outcomes in 827 of 869 patients who had undergone ACI with Chondron, periosteum (ACI-C/ACI-P) or MACI to identify factors that influenced the outcome. Follow-up ranged from 2 to 12 years with a mean timeframe of 6.2 years. Four hundred twenty-one procedures were performed on the medial femoral condyle,109 on the lateral femoral condyle, 200 on the patella; and 50 on the trochlea. Significant postoperative improvements in function and pain scores were noted for all outcome measures. The outcomes demonstrated an overall graft survival of 78% at 5 years and 51% beyond 10 years following both autologous chondrocyte implantation (ACI-C/ACI-P and MACI) techniques. Authors concluded that ACI for the treatment of osteochondral defects of the knee can achieve positive results.

   Nassar et al. (2025) conducted a systematic review and metanalysis evaluating ACI, MACI, osteochondral autograft transplantation (OAT), and osteochondral allograft transplantation (OCA) for tibiofemoral cartilage defects. Across 47 studies including 1,993 patients, all procedures demonstrated statistically and clinically significant improvements in knee pain and function as measured by IKDC, Lysholm, Tegner, and Visual Analog Scale scores, with improvements exceeding minimal clinically important difference (MCID) thresholds. No procedure showed superior overall outcomes, although OAT was the only technique to exceed the patient acceptable symptom state (PASS) threshold for IKDC. The authors concluded that all four techniques may provide meaningful symptomatic benefit in appropriately selected patients; however, given heterogeneity, predominance of nonrandomized studies, and variable risk of bias, the evidence does not support one procedure as universally superior, and treatment selection should be individualized based on patient and defect characteristics.

3. U.S. Food & Drug Administration Information

   The U.S. Food and Drug Administration (FDA) regulates biological products used for Autologous Chondrocyte Implantation. A biologic may be licensed under a biologics license application, and applicable FDA information may include the licensed indication, reference product status, and biosimilar or interchangeable biosimilar status, when applicable.

   To search for FDA-approved and licensed biological products, including licensed biosimilar and interchangeable products, regulated by the Center for Drug Evaluation and Research (CDER), please visit the FDA-licensed (approved) Biological Products Database. FDA licensure is provided for background and supporting information only and does not independently establish medical necessity or VA coverage.

4. Medicare Coverage Determinations

   There are no available Medicare coverage determinations. VA and Medicare are governed by separate laws and regulations; thus, VA coverage determinations may be different.

5. TRICARE Policy Manual

   Available TRICARE coverage determinations are listed below as a resource. VA and TRICARE are governed by separate laws and regulations; thus, VA coverage determinations may be different.

   TRICARE Policy Manual 6010.60-M, Chapter 4, Section 6.1

   • 4.2: Autologous cultured chondrocytes on porcine collagen membrane (i.e. Matrix-Induced Autologous Chondrocyte Implantation [MACI]) to treat cartilage defects of the knee is proven
   • 4.12: Autologous Chondrocyte Implantation (ACI), with Carticel, for the repair of patellar cartilage lesions is proven

6. Health Care Procedural Coding Information

   The following CPT^®/HCPCS codes listed in this section are provided for informational purposes only. Inclusion or exclusion of a code does not constitute or imply VA coverage or provider reimbursement. The list of codes may not be all-inclusive since the American Medical Association (AMA) and Centers for Medicare & Medicaid Services (CMS) code updates may occur more frequently than CDI updates. Please refer to section II.a. in this document to review indications and clinical criteria for medical necessity.

   The following CPT/HCPCS codes may be considered medically necessary/covered if the indications and clinical criteria outlined in section II.a. are met. Additional codes may also apply.

   CPT/HCPCS Code	Description
   27412	Autologous chondrocyte implantation, knee
   29870	Arthroscopy, knee, diagnostic, with or without synovial biopsy (separate procedure)
   J7330	Autologous cultured chondrocytes, implant

   CPT copyright ^© 2026 American Medical Association. All rights reserved.

IV. Definitions

Term	Definition
Arthroscopy	A minimally invasive surgical procedure involving visual examination of the interior of a joint with an arthroscope to diagnose or treat various conditions or injuries and to repair or remove injured or diseased tissue or bone
Articular	Of or relating to a joint
Autologous	Derived from the same individual, involving one individual as both donor and recipient
Biocompatible	The property of being biologically compatible by not producing a toxic, injurious, or immunologic response in living tissue
Chondrocyte	A cartilage cell that produces substances that make up cartilage tissue
Chondrogenesis	The process of generating chondrocytes
Debridement	Removal of devitalized or infected tissue
Focal	Relating to a localized area
Hyaline	A type of cartilage that is predominantly type 2 collagen
Microfracture	An articular cartilage repair surgical technique that works by creating tiny fractures in the underlying bone to stimulate a healing response
Scaffold	A framework or structural element that holds cells or tissues together
Subchondral drilling	Surgical procedure where small holes are drilled through damaged joint cartilage into the underlying bone to stimulate a healing response

V. References

Defense Health Agency (2015, April 01). Musculoskeletal System. TRICARE Policy Manual 6010.60-M. Chapter 4, Section 6.1. Retrieved September 25, 2023.

Edwards, P. K., Ackland, T., & Ebert, J. R. (2014). Clinical rehabilitation guidelines for matrix-induced autologous chondrocyte implantation on the tibiofemoral joint. The Journal of orthopaedic and sports physical therapy, 44(2), 102–119.

MCG Health. (2023, June 27). Autologous Chondrocyte Implantation. Ambulatory Care. 27th Edition.

Minas, T., Ogura, T., & Bryant, T. (2016). Autologous Chondrocyte Implantation. JBJS essential surgical techniques, 6(2), e24.

Minas, T., Von Keudell, A., Bryant, T., & Gomoll, A. H. (2014). The John Insall Award: A minimum 10-year outcome study of autologous chondrocyte implantation. Clinical orthopaedics and related research, 472(1), 41–51.

Na, Y., Shi, Y., Liu, W., Jia, Y., Kong, L., Zhang, T., Han, C., & Ren, Y. (2019). Is implantation of autologous chondrocytes superior to microfracture for articular-cartilage defects of the knee? A systematic review of 5-year follow-up data. International Journal of Surgery, 68, 56–62.

Nassar, J. E., Guerin, G., Keel, T., Russo, R., Familiari, F., Tollefson, L. V., & LaPrade, R. F. (2025). Autologous chondrocyte implantation, matrix-induced autologous chondrocyte implantation, osteochondral autograft transplantation and osteochondral allograft improve knee function and pain with considerations for patient and cartilage defects characteristics: A systematic review and meta-analysis. Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA, 33(8), 2745–2762.

Nawaz, S. Z., Bentley, G., Briggs, T. W., Carrington, R. W., Skinner, J. A., Gallagher, K. R., & Dhinsa, B. S. (2014). Autologous chondrocyte implantation in the knee: mid-term to long-term results. The Journal of bone and joint surgery. American volume, 96(10), 824–830.

Saris, D., Price, A., Widuchowski, W., Bertrand-Marchand, M., Caron, J., Drogset, J. O., Emans, P., Podskubka, A., Tsuchida, A., Kili, S., Levine, D., & Brittberg, M. (2014). Matrix-applied characterized autologous cultured chondrocytes versus microfracture. The American Journal of Sports Medicine, 42(6), 1384–1394.

Terzidis, I. P., Christodoulou, A. G., Ploumis, A. L., Metsovitis, S. R., Koimtzis, M., & Givissis, P. (2004). The appearance of kissing contusion in the acutely injured knee in the athletes. British journal of sports medicine, 38(5), 592–596.

U.S. Food & Drug Administration Purple Book Database. (n.d.). Retrieved August 3, 2023.

VI. CDI History/Revision Information

Date	Summary of Updates
10/01/2026	Added “Health Care Procedural Coding Information” section Updated “Definitions” section Added Arthroscopy and Chondrogenesis
11/01/2024	New CDI created describing medically necessary indications / not medically necessary indications

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