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# Arthritis on X-ray: osteoarthritis vs inflammatory

- Finding

Wear-and-tear arthritis builds extra bone at the joint edges; inflammatory arthritis eats into the bone and thins it around the joint.

Updated Nov 13, 2026

## Key points

- LOSS = osteoarthritis: uneven Loss of space, Osteophytes, Sclerosis, Subchondral cysts; bone density normal.
- Rheumatoid: even narrowing, periarticular osteopenia, marginal erosions, symmetric MCP/PIP/wrist, DIP spared.
- Gout: punched-out «rat-bite» erosions with overhanging edges, joint space kept.
- Early rheumatoid arthritis can have a normal X-ray; ultrasound and MRI see it sooner.

## What it is

Plain X-ray is the first image in chronic joint pain. The question is whether the pattern is degenerative (osteoarthritis) or inflammatory (rheumatoid arthritis and its relatives). Osteoarthritis narrows the joint unevenly, where load is greatest, and the bone answers by making osteophytes and sclerosis; bone density is normal. Rheumatoid arthritis narrows the joint evenly, thins the bone around it (periarticular osteopenia) and makes erosions at the joint margins, without osteophytes. Where the changes are matters as much as what they are: DIP joints, base of the thumb, knees and hips for osteoarthritis; wrists, MCP, PIP and MTP joints, both sides alike, for rheumatoid arthritis. Early inflammatory disease can have a normal X-ray; ultrasound and MRI see synovitis and erosions sooner.

## What it looks like

- Osteoarthritis (LOSS): Loss of joint space (uneven), Osteophytes, Subchondral sclerosis, Subchondral cysts.
- Osteoarthritis sites: DIP (Heberden nodes), PIP (Bouchard nodes), first carpometacarpal joint, knee (medial compartment), hip, spine.
- Rheumatoid arthritis: soft-tissue swelling, periarticular osteopenia, even joint space loss, marginal erosions; no osteophytes.
- Rheumatoid sites: wrist (ulnar styloid), MCP and PIP joints, MTP joints (the fifth early); the DIP joints are spared.
- Late rheumatoid changes: ulnar deviation, subluxation, swan-neck and boutonnière deformities, carpal fusion, atlantoaxial instability.
- Gout: punched-out erosions with overhanging edges and sclerotic borders, joint space kept until late; CPPD: calcified cartilage (chondrocalcinosis).

## Why it looks that way

- In osteoarthritis cartilage wears where load is highest, so narrowing is uneven; bone under stress thickens (sclerosis) and grows spurs at the margins.
- In rheumatoid arthritis inflamed synovium (pannus) attacks the «bare areas» at the joint margins first, where bone is not covered by cartilage; hyperaemia thins the nearby bone.
- Cartilage loss in inflammatory disease is diffuse, so the whole joint narrows evenly and the femoral head can migrate straight into the acetabulum.

| Pattern | Joint space | Bone density | Hallmark | Typical sites |
| --- | --- | --- | --- | --- |
| Osteoarthritis | Narrowed unevenly | Normal | Osteophytes, sclerosis, subchondral cysts | DIP, PIP, thumb base, knee, hip |
| Rheumatoid arthritis | Narrowed evenly, both sides alike | Low around the joint | Marginal erosions, no osteophytes | Wrist, MCP, PIP, MTP; spares DIP |
| Psoriatic arthritis | Variable; may widen | Often normal | Erosions with new bone, «pencil-in-cup», periostitis | DIP, whole digit, asymmetric |
| Gout | Kept until late | Normal | Punched-out erosions with overhanging edges, tophi | First MTP, feet, hands, elbow |
| CPPD (pseudogout) | Narrowed | Normal | Calcification of cartilage (chondrocalcinosis) | Knee menisci, wrist (triangular cartilage), symphysis |

## Differential and pitfalls

- X-ray severity and pain do not match well: a severe-looking knee may hurt little, and the reverse.
- A normal X-ray does not rule out early rheumatoid arthritis; erosions take months to show.
- Erosive (inflammatory) hand osteoarthritis has central «gull-wing» erosions of the DIP and PIP joints; it is not rheumatoid arthritis.
- A single hot, swollen joint is septic until proved otherwise: the X-ray does not exclude infection, aspiration does.
- Knee joint space is judged on weight-bearing films; a lying film can make it look normal.

## Next step

- Suspected inflammatory arthritis: X-ray both hands, wrists and feet as a baseline, with serology, and refer to rheumatology.
- Normal X-ray but strong clinical suspicion of synovitis: ultrasound (with Doppler) or MRI to show synovitis and early erosions.
- Knee osteoarthritis: weight-bearing AP and lateral films; MRI is rarely needed for diagnosis.
- Longstanding rheumatoid arthritis before surgery or intubation, or with neck pain or neurological signs: cervical spine imaging for atlantoaxial instability.
- Acute hot swollen joint: aspirate for cell count, crystals and culture; call a senior if septic arthritis is possible.

## Memory aid

LOSS for osteoarthritis: Loss of joint space, Osteophytes, Subchondral sclerosis, Subchondral cysts.

## Test yourself

Think of the answer, then tap the question to see it.

## What are the four X-ray features of osteoarthritis?

Uneven loss of joint space, osteophytes, subchondral sclerosis and subchondral cysts (LOSS).

## Why do rheumatoid erosions appear first at the joint margins?

Because the inflamed synovium reaches the «bare areas» there first, where bone lies inside the capsule but is not covered by cartilage.

## Which hand joints are typically spared in rheumatoid arthritis but involved in osteoarthritis?

The distal interphalangeal (DIP) joints.

## What do gout erosions look like on X-ray?

Punched-out erosions with sclerotic borders and overhanging edges, often near soft-tissue tophi, with the joint space kept until late.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/radiology/arthritis-on-x-ray-osteoarthritis-vs-inflammatory/)

## Elsewhere in DurgiPedia

- [Joint examination: inspection, palpation and range of motion](https://durgical.com/en/clinical-exam/joint-examination-inspection-palpation-and-range-of-motion/)
- [Hand deformities: Heberden, Bouchard, swan neck, boutonnière](https://durgical.com/en/clinical-exam/hand-deformities-heberden-bouchard-swan-neck-boutonniere/)

## Connections

## Related 5

- [Hip X-ray: femoral neck fracture](https://durgical.com/en/radiology/hip-x-ray-femoral-neck-fracture/)
- [Wrist and hand X-rays: distal radius and scaphoid](https://durgical.com/en/radiology/wrist-and-hand-x-rays-distal-radius-and-scaphoid/)
- [Cervical spine imaging in trauma: who needs it](https://durgical.com/en/radiology/cervical-spine-imaging-in-trauma-who-needs-it/)
- [Ultrasound: echogenicity, probes, Doppler and artefacts](https://durgical.com/en/radiology/ultrasound-echogenicity-probes-doppler-and-artefacts/)
- [MRI: T1, T2, FLAIR and diffusion](https://durgical.com/en/radiology/mri-t1-t2-flair-and-diffusion/)

## Related conditions 6

- [Hip Osteoarthritis](https://durgical.com/en/conditions/hip-osteoarthritis/)
- [Rheumatoid arthritis](https://durgical.com/en/conditions/rheumatoid-arthritis/)
- [Rheumatoid arthritis of the hand and wrist](https://durgical.com/en/conditions/rheumatoid-arthritis-of-the-hand-and-wrist/)
- [Gout](https://durgical.com/en/conditions/gout/)
- [Pseudogout (CPPD) of the Knee](https://durgical.com/en/conditions/pseudogout-of-the-knee/)
- [Psoriatic arthritis](https://durgical.com/en/conditions/psoriatic-arthritis/)

[← All of radiology](https://durgical.com/en/radiology/)

Educational content; it does not replace a radiologist's report and is not a clinical instruction. Each study is ordered on the patient's assessment and your institution's protocols.

Sources: [Osteoarthritis](https://www.ncbi.nlm.nih.gov/books/NBK482326/) (StatPearls (NCBI Bookshelf), 2023); [Rheumatoid Arthritis](https://www.ncbi.nlm.nih.gov/books/NBK441999/) (StatPearls (NCBI Bookshelf), 2023); [Hand and Wrist Rheumatoid Arthritis](https://www.ncbi.nlm.nih.gov/books/NBK560890/) (StatPearls (NCBI Bookshelf), 2023).

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