When do I need an X-ray? A guide to pain and injuries

What can an X-ray show?

X-rays are useful for many fractures, dislocations and bony joint changes. They provide much less detail about muscles, tendons and other soft tissues. A clinician may choose ultrasound, MRI or another test for a different question; more detailed imaging is not automatically the best first step.

X-rays use ionizing radiation. Tell the referring clinician and radiographer if you may be pregnant so they can plan appropriately.

Reference: RadiologyInfo (ACR / RSNA) — Bone X-ray

After a fall or injury: is a fracture possible?

Seek prompt medical assessment if you cannot bear weight, swelling is substantial or increasing, or pain is severe or worsening. A clinician can decide whether an X-ray is needed; swelling alone does not identify the injury.

For an acute wrist injury after a fall, X-rays are commonly the first imaging test. Bone health also matters: new back pain after minor trauma deserves particular attention in someone with osteoporosis or long-term steroid use. The right test depends on the site and clinical findings.

Reference: NHS — Sprains and strains · RadiologyInfo (ACR / RSNA) — Acute Hand and Wrist Trauma · RadiologyInfo (ACR / RSNA) — Low Back Pain: Appropriate Imaging

Lower back pain: why imaging often is not the first step

For most new lower back pain without warning signs, routine imaging does not speed recovery. Scans can also show changes unrelated to the pain. Choosing Wisely Canada recommends making the decision around the history and examination, rather than ordering a scan simply because pain is present.

Back pain with fever or feeling unwell needs prompt medical assessment. Tell your clinician about a cancer history or unexplained weight loss. If symptoms persist or worsen despite care, arrange reassessment. There is no automatic deadline that makes everyone need an X-ray; suspected nerve compression or infection may require a different test, such as MRI.

Reference: Choosing Wisely Canada — Imaging Tests for Lower Back Pain · RadiologyInfo (ACR / RSNA) — Low Back Pain: Appropriate Imaging · NHS — Back pain

Persistent joint pain: is MRI always better?

The question being investigated matters more than choosing the most detailed scan. For suspected knee osteoarthritis, when imaging is needed, weight-bearing X-rays are generally more useful as the initial test than MRI. Choosing Wisely Canada advises against routine MRI for osteoarthritis or suspected degenerative meniscal tears. Examination findings and response to care help determine whether further investigation is worthwhile.

Reference: Choosing Wisely Canada / CASEM — Sport and Exercise Medicine Recommendations

What if my X-ray is normal but I still hurt?

A normal image does not explain every symptom or exclude every injury. For a wrist injury that remains suspicious despite normal initial X-rays, repeat X-rays, CT or MRI may be appropriate. Ask about follow-up if pain or function is not improving; a normal first image is not, by itself, clearance to return to sport.

Reference: RadiologyInfo (ACR / RSNA) — Acute Hand and Wrist Trauma

Four useful questions before an imaging test

Use the discussion to understand the plan, including what happens if no scan is needed today.

• What problem are we trying to confirm or rule out?
• How would the result change my treatment or activity advice?
• Why is this the most suitable test for that question?
• When should I be reassessed, and which new symptoms need urgent care?

Where physiotherapy fits

At Harrison Zhang Physio in Markham, an assessment considers your symptoms, health history, movement and goals. Bring existing imaging reports if you have them. Harrison can discuss rehabilitation and whether further medical assessment is appropriate. Care is available in English, Mandarin Chinese and Cantonese at Space Wellness.