Agili-C

Agili-C (CartiHeal) is a cell-free, off-the-shelf biphasic plug derived from aragonite — coral-derived calcium carbonate. It is implanted press-fit into an osteochondral socket in a single surgery, and is designed to be resorbed and remodeled by host cells into subchondral bone below and cartilage above. No cultured cells, no donor tissue: the claim is that the material itself recruits and organizes host repair.

The pivotal trial

A multicenter RCT across 26 sites randomized 251 patients with knee chondral or osteochondral lesions — including knees with mild-to-moderate OA — 2:1 to the implant or surgical standard of care (debridement or microfracture at the surgeon's discretion). At 24 months the implant group had roughly twice the mean KOOS improvement, a 77.8% responder rate versus 33.6%, 88.5% versus 30.9% defect fill on MRI, and 7.2% versus 21.4% failure. This trial underpinned FDA approval in March 2022 after Breakthrough Device designation — a broader indication than most cartilage devices, explicitly including mild-to-moderate OA knees.

The 5-year update

The 2026 follow-up of the same trial shows superiority maintained: KOOS 81.0 versus 59.1 (a 22.6-point difference), responder rate 74.7% versus 29.6%, treatment failure 15.0% versus 35.7%. The honest reading has two halves. Superiority held — and implant-arm failures roughly doubled between years 2 and 5, from 7.2% to 15.0%. Durability is good at 5 years, not proven beyond.

A separate uncontrolled multicenter cohort of 86 mild-to-moderate OA knees showed all KOOS subscales improved at 24 months (pain 49.6 to 79.5) with 9.3% needing revision — the study that extended the indication toward OA.

What the trial does not tell you

Everything above comes from one sponsor-run program: CartiHeal funded and ran the pivotal trial (the company was acquired by Bioventus, then restructured — commercial turbulence worth knowing about when asking about availability). The trial was open-label, and KOOS is patient-reported — susceptible to expectation effects in unblinded surgical trials. The comparator was debridement or microfracture, procedures documented elsewhere to fade after 2–5 years. Beating a fading comparator at 5 years is meaningful, but it is not the same as beating MACI, OATS, or allograft — no head-to-head against any of those exists, and no independent, non-sponsor trial has been published.

Who is inside the studied indication

The studied envelope: ICRS grade III–IV chondral and osteochondral defects of the femoral condyles or trochlea, total treatable area up to about 7 cm², with or without mild-to-moderate OA (Kellgren-Lawrence up to 3), without significant uncorrected malalignment or instability. Outside that envelope, you are outside the data. The practical draw is the single surgery — no biopsy or culture stage — with protected weight bearing early and return to full activity over roughly 6–12 months.

Questions for your surgeon

• Am I inside the studied indication — lesion site, size, and no more than mild-to-moderate OA?
• Is the implant actually available here, given the company's commercial turbulence?
• If the implant fails, what does revision look like — the subchondral bone is drilled, so failed cases may face more complex revisions?
• Why this over MACI or OATS for my defect, given no head-to-head exists?

Safety

The trial safety profile was acceptable; failures present as persistent symptoms or revision (15% by 5 years in the implant arm). A single surgery avoids two-stage risks, but the subchondral bone is reamed, which raises the stakes of failure. Ten-year durability and real-world results in the labeled mild-OA population remain open questions.