Preserve or replace
A knee replacement swaps the worn joint for an implant; NanoACi is a single injection that preserves your own joint. Here is how to choose, honestly.
Reviewed byProfessor Paul Lee MBBch, FRCS (Tr & Orth), PhDCartilage and joint preservation expertiseA knee replacement removes the worn joint surfaces and replaces them with metal and plastic. It is major surgery under general anaesthetic, established and highly effective for true end-stage arthritis, from £18,500. NanoACi is a single-session injection that preserves your own joint, using your own cells, a ChondroFiller scaffold and PRF, from £8,000. Being bone-on-bone does not automatically mean a replacement.
Both are discussed honestly at London Cartilage Clinic. NanoACi may delay or avoid a replacement, or be tried first; a knee replacement remains the right call for genuine end-stage arthritis, severe deformity or a joint that is beyond preserving.
| What to compare | Knee replacement | NanoACi |
|---|---|---|
| What it does | Removes the worn cartilage and bone and replaces the joint surfaces with metal and plastic implants | A single injection that preserves your own joint, delivering your own cells, a ChondroFiller scaffold and PRF |
| Surgery or injection | Major surgery under general anaesthetic, with a hospital stay | An outpatient injection under local anaesthetic, around thirty minutes |
| Your own joint | The joint surfaces are removed and replaced | Your own joint is kept and helped to repair; nothing is removed |
| Best suited to | True end-stage arthritis: severe deformity or whole-joint wear where the surface cannot be preserved | Cartilage wear and damage where the joint is still worth protecting, across the range of wear |
| If you are bone-on-bone | One established answer for genuine end-stage wear | Not ruled out; often paired with an Arthrosamid injection, and may delay or avoid a replacement |
| How long it lasts | Definitive, but the implant does not last forever and can need revision in time | Preserves your own tissue; results vary and it can be repeated or followed by a replacement later if needed |
| Recovery | Weeks of staged rehabilitation after major surgery | Most people return to light daily activity the same day |
| Available at London Cartilage Clinic | Yes, from £18,500 | Yes, £8,000, or £8,500 all-inclusive |
Both are genuine options at London Cartilage Clinic; a knee replacement remains the right call for some joints.
The honest position is that these are not rivals so much as different answers to different joints. A knee replacement is a proven, highly effective operation for true end-stage arthritis, and for a joint with severe deformity or whole-joint wear it can transform someone’s life; its trade-offs are that it is major surgery and the implant does not last forever. Being told you are bone-on-bone does not, on its own, mean a replacement is the only route. NanoACi, often with an Arthrosamid injection to cushion the joint, may delay or avoid a replacement, or be tried first while the joint is still worth preserving. Because both are on the table here, the consultation is a genuine review of which suits your joint, not a push towards one.
No, not automatically. Bone-on-bone describes advanced wear, but it does not by itself decide the treatment. NanoACi, usually paired with an Arthrosamid injection here, may delay or avoid a replacement, or be tried first. For some joints a replacement is still the right call: severe deformity, whole-joint end-stage disease, or a joint that has moved beyond what regeneration can help. Your imaging and a consultation settle it, not your symptoms.
They do different jobs, so it is not a straight better-or-worse. A knee replacement is definitive and highly effective for true end-stage arthritis, but it is a big operation under general anaesthetic and the implant does not last forever. NanoACi preserves your own joint with a single injection and carries far less upheaval, but it is not a substitute for a joint that is genuinely beyond saving. Professor Lee will be honest about which one fits your joint.
Yes. NanoACi preserves your own joint and removes no bone, so it does not close the door on a replacement if one is needed later. Many people prefer to try to preserve the joint first, especially while they are still active. If regeneration is not enough, a replacement remains available.
A knee replacement is from £18,500. NanoACi is £8,000, or £8,500 all-inclusive, which covers an MRI scan, your consultation, the NanoACi session and a follow-up. See the NanoACi cost page for the detail.
The decision rests on your imaging and examination, not on symptoms alone. Start with a free discovery call, then book a consultation so Professor Lee can review your scans and set out the honest options, which may include NanoACi with an Arthrosamid injection, or a joint replacement review. See the NanoACi treatment page or the knee replacement page.
Still have more specific concerns?
Free Discovery CallOptions that our doctors may discuss include NanoACi, ChondroFiller, Mytocel MSK, joint replacement, established conservative care or surgery, depending on examination and imaging.
Bone-on-bone wear does not automatically mean a replacement. The fairest next step is a review of your imaging. Start with a free discovery call, or book a consultation with Professor Lee, who will set out the honest options for your joint.
London Cartilage Clinic
Clinical updates, cartilage treatment guidance, and recovery-focused articles from our specialist team.
Hip cartilage loss causes pain that peaks at night because lying down concentrates load on the posterior femoral head—precisely the surface most often damaged by wear—without the postural relief daytime walking provides. ChondroFiller, an acellular collagen scaffold, addresses this through mechanical cushioning and biological repair.
ACI recovery to high-impact sport takes twelve to eighteen months, not the six months most patients expect—a gap driven by biology, not surgical complexity, that consistently undermines rehabilitation adherence.
Grade 3 cartilage damage on knee MRI means a lesion extending beyond the halfway point with the subchondral bone plate intact; Grade 4 means the lesion extends through the bone. The grade does not determine treatment — size, location, and symptoms do.
