CARTIHEAL◊ AGILI-C◊ Cartilage Repair Implant in osteoarthritic knees: what the 2- and 5-year evidence tells us
Key takeaways
Within the studied patient population, clinical improvements were observed in patients with mild-to-moderate osteoarthritis (OA) following treatment with the CARTIHEAL◊ AGILI-C◊ Cartilage Repair Implant1,2
A 2-year multi-center prospective case series of 86 OA patients demonstrated that the CARTIHEAL Implant provided significant improvements in pain, function, and quality-of-life at two years, alongside progressive defect fill1
The 5-year randomized controlled study reported greater improvements in overall Knee Injury and Osteoarthritis Outcome Scores (KOOS), a higher responder rate and fewer treatment failures in OA patients treated with the CARTIHEAL Implant compared with surgical standard of care (SSOC)2
The OA subgroup data raises an important clinical question: should early degenerative change be viewed as a barrier to meaningful cartilage repair outcomes?
The challenge
High-quality evidence to guide treatment management in patients with focal cartilage lesions and early degenerative change is limited.1,2
These patients often present with chondral or osteochondral defects that contribute to pain, functional limitation, and progressive joint degeneration.1,2
Historically, this population has been underrepresented in cartilage repair trials, with OA frequently considered a possible contraindication due to a biologically challenging joint environment.1
Why this matters
In an arthroscopic analysis of 15,074 knee chondral lesions, cartilage lesions were classed as localized focal osteochondral or chondral lesions in 67% of cases and OA in 29% of cases2,3
Standard surgical options (e.g., debridement or microfracture) may provide short-term symptom relief but do not address the underlying biological and mechanical drivers of joint degeneration, with outcomes often declining over time1,2
There remains a need for treatment strategies that address both focal defects and the underlying joint environment
Evidence for the CARTIHEAL Implant in osteoarthritic knees
A 2-year multi-center prospective case series in patients with Kellgren-Lawrence (KL) grades 2–3 OA1, and a 5-year multicenter RCT in a broader population with KL grades 0–3 OA2, provide insights into outcomes with the CARTIHEAL Implant in osteoarthritic knees for patients with:
up to 3 treatable chondral and/or osteochondral defects
total treatable area 1 to 7cm2
bony defect depth ≤8mm
ICRS = International Cartilage Regeneration & Joint Preservation Society grade
Figure. Overview of the CARTIHEAL Implant studies across OA severity categories (KL grades 1–3).1,2
Could meaningful cartilage repair be achieved in osteoarthritic knees?
2-year prospective outcomes1
A multicenter prospective case series evaluated 86 patients with mild to moderate OA (KL 2–3) who underwent treatment with the CARTIHEAL Implant. At 2 years, patients reported substantial improvements in symptoms and function, suggesting that clinically meaningful improvements were observed despite the presence of OA. KOOS Pain improved from 49.6 to 79.5, activities of daily living from 56.1 to 84.1, and quality-of-life from 23.5 to 54.9. Improvements were observed across all KOOS subscales and the International Knee Documentation Committee (IKDC) score, with all changes reaching statistical significance (P<0.001)¹
Figure. Continued improvement in overall KOOS and IKDC subjective scores at baseline, 6, 12, 18 and 24-month follow-up1
Just as importantly, the clinical improvements were accompanied by evidence of structural repair. MRI demonstrated progressive defect fill over time, reaching approximately 78.7% coverage at 2 years, representing a significant increase over earlier follow-up assessments (P<0.001)1
Treatment failure requiring revision surgery occurred in 8 patients within 2 years1.
While this was not a comparative study, it provided an important early signal that clinically meaningful improvements could be achieved with the CARTHIHEAL Implant in patients with OA.
The next question was whether these encouraging early findings could be confirmed against standard surgical care in a larger randomized controlled study.
Would those early signals hold up against surgical standard of care?
A randomized controlled study with 5-year follow-up2
The study provided longer-term comparative evidence, that in a population of patients with KL grades 0–3, the early improvements observed with the CARTIHEAL Implant1 were maintained through 5 years, with a significantly higher responder rate (defined as ≥30-point improvement in overall KOOS) versus SSOC (74.7% vs 29.6%), alongside greater improvements in patient-reported outcomes and lower treatment failure rates.²
Figure. Primary endpoint changes in Knee Injury and Osteoarthritis Outcome Score (KOOS) overall score from baseline to 60 months2
At 60-months fewer CARTIHEAL Implant-treated patients (1.8%) required subsequent knee replacement or osteotomy compared with those receiving SSOC (9.5%; P=0.008).2
The randomized study provides evidence that clinical improvements were observed in patients with OA. Among patients with KL grades 2–3 OA, 74.6% of CARTIHEAL Implant-treated patients achieved a clinically meaningful response compared with 36.2% receiving SSOC. Treatment failure was also substantially lower in the CARTIHEAL Implant group(13.2% vs 40.7%; P<0.001)²
Figure. Mean change in overall KOOS scores from baseline. Significantly greater improvement in overall KOOS at 5 years for patients treated with the CARTIHEAL Implant across OA severity categories (KL grades 1–3).2
Greater improvements for patients treated with the CARTIHEAL Implant were reported across pain, symptoms, function, sport and quality-of-life measures compared to SSOC.2
Importantly, in a prespecified OA subgroup analysis, clinical improvements were observed across all OA severity categories studied. Among patients treated with the CARTIHEAL Implant, overall KOOS improved by 39.4 points in KL grades 0–1 and by 39.8 points in KL grades 2–3.2
Clinical improvements were observed across OA severity categories in the subgroup analysis.
Sustained pain reduction
Functional improvement
QoL improvements
Likelihood of a clinically important response
In the RCT, OA progression was reported for zero patients in the implant group and four patients in the SSOC group; however, the small number of events limits interpretation.2
What this means for clinical practice
More representative evidence
Together, the proof-of-concept and confirmatory studies include patients commonly seen in practice, including those with early degenerative changes and focal cartilage defects, helping to address a long-standing evidence gap between clinical trials and clinical practice1,2.
OA may not be a barrier
Importantly, the early benefits of the CARTIHEAL Implant were maintained at 5 years, providing longer-term evidence in a patient population for which cartilage repair data have been limited.2
Expanding joint-preservation options
These findings contribute to the growing evidence base around joint-preservation strategies in patients with focal cartilage lesions and early degenerative change2 .
Historically, the presence of osteoarthritis has created uncertainty around the role of focal cartilage repair in degenerative knee environments. The available 2- and 5-year evidence suggests that, within the studied eligibility criteria, clinically meaningful improvements were observed in patients with mild-to-moderate OA, with longer-term comparative data showing greater KOOS improvement, higher responder rates and fewer treatment failures with the CARTIHEAL Implant than with surgical standard of care.¹˒²
These findings do not remove the need for careful interpretation. Rather, they raise a more nuanced clinical question: when focal cartilage defects and early degenerative change coexist, should OA alone continue to define the limits of cartilage repair?
The CARTIHEAL AGILI-C Implant scaffold is indicated for the treatment of an International Cartilage Repair Society grade III or above knee-joint surface lesion(s), with a total treatable area of 1-7cm2, without severe osteoarthritis (Kellgren-Lawrence grade 0–3).
Contraindications
CARTIHEAL AGILI-C Implant should not be implanted in subjects with the following conditions:
Active or latent, bone or joint infection at the surgical site; Active infection elsewhere in the body; Neuropathic joint; Hypersensitive, allergic, or intolerance of materials containing calcium carbonate or coral derivatives; Critical limb ischemia; Any known tumor of the knee area; Severe Osteoarthritis of the index knee, defined as grade 4 according to the Kellgren-Lawrence Grading; Uncontained lesion - lack of vital bone wall, at least 2mm thick, surrounding the implantation site; Subchondral bone defect or bone cyst depth deeper than 8mm; Inability to position the implant 2mm recessed relative to the articular surface; Osteochondral or cystic lesions larger than what the implant can cover; Implantation inside avascular necrosis.
Warnings
The safety and effectiveness of the CARTIHEAL AGILI-C Implant has not been established in patients with the following conditions: Morbid obesity (BMI >35); Known insulin dependent diabetes mellitus; Immunocompromised patients; including patients receiving a previous intra-articular steroid injection within the last 1 month; Systemic conditions affecting wound healing; Systemic bone disorder, such as but not limited to, osteoporosis and osteogenesis imperfecta; Chemotherapy during the past 12 months; Ligamentous instability; Significant malalignment; Total or subtotal meniscectomy or lack of functional meniscus; Inflammatory arthropathy or crystal-deposition arthropathy; Skeletally immature; Inability to refrain from contact sports/high-impact activities during recovery period; Noncompliance due to major psychiatric disorder, alcohol or drug abuse; Skin conditions within the field of surgery. The implant is not indicated for treatment in Patellar cartilage and osteochondral defects or for use in other joints.
Risks and side effects
As with any surgical procedure, there are risks you should be aware of to help make your decision. The most common risks that occur with the CARTIHEAL AGILI-C Implant include increased transient or chronic pain of the operated joint, increased swelling and/or effusion of the operated joint, decreased range of motion, hemarthrosis and contusion.
In addition to the risks above, there are other risks that may occur. For full product information, including indications for use, contraindications, precautions, warnings and adverse events, please consult the product’s applicable Instructions for Use (IFU) prior to use.
Disclaimers
This content is intended for healthcare professionals only.
Products may not be available in all markets because product availability is subject to the regulatory and/or medical practices in individual markets. Please contact your Smith+Nephew representative or distributor if you have questions about the availability of Smith+Nephew products in your area.
References
Kon E, Di Matteo B, Verdonk P, Drobnic M, Dulic O, Gavrilovic G, et al. Aragonite-based scaffold for the treatment of joint surface lesions in mild to moderate osteoarthritic knees: results of a 2-year multicenter prospective study. Am J Sports Med. 2021;49(3):588–598. https://doi.org/10.1177/0363546520981750
Altschuler N, Zaslav KR, Di Matteo B, Sherman SL, Gomoll AH, Hacker SA, et al. Five-year follow-up of a multicenter randomized controlled trial comparing an aragonite-based scaffold with microfracture and debridement for chondral and osteochondral knee lesions. Am J Sports Med. 2026;54(6):1376–1385. https://doi.org/10.1177/03635465261437781
Widuchowski W, Widuchowski J, Trzaska T. Articular cartilage defects: study of 25,124 knee arthroscopies. Knee. 2007;14(3):177-182. https://doi.org/10.1016/j.knee.2007.02.001
