What an X-ray shows
Cartilage is invisible on X-ray. What we actually read is the space between bones, where cartilage used to hold them apart, plus the bone's response to losing it: spurs (osteophytes), hardened surfaces (sclerosis), and cysts. Weight-bearing views matter, which is why we X-ray your knee standing: a knee that looks respectable lying down can close to bone-on-bone under load.
The words on your report, translated
| Report language | Plain meaning |
|---|---|
| Joint space narrowing | Cartilage thinning in that compartment |
| Osteophytes | Bone spurs, the bone remodeling around arthritis |
| Subchondral sclerosis | Bone hardening where cartilage no longer cushions |
| Subchondral cysts | Small fluid pockets in stressed bone |
| “Bone-on-bone” | Full-thickness cartilage loss in at least one area |
| Kellgren-Lawrence grade 1–4 | A standard severity scale; 4 is most severe |
The most important sentence in this guide
This is why “bone-on-bone” is a description, not an instruction. It tells us the cartilage is gone in a spot. It does not tell us how you sleep, whether you can work, or what you've had to give up, and those are the things surgery is actually for.
Why you usually don't need an MRI
For established arthritis, weight-bearing X-rays typically answer the question. An MRI shows the same arthritis in expensive detail, and almost every arthritic knee MRI also shows a degenerative meniscus tear, a common finding that usually doesn't change the plan. Advanced imaging earns its keep when the story and the films don't match, or when something beyond arthritis is suspected.
What actually drives the recommendation
- Your symptoms and what they're taking from you
- Your examination
- What you've already tried
- Your health, goals, and timeline
- Then the X-ray, confirming that arthritis explains the story