Many orthopedic conditions like hip pain, knee pain, or low-back pain seem to come on for no apparent reason. Often, there is a slow, gradual onset and progression of pain. Your symptoms may come and go, or they may simply get worse and worse until your functional mobility is compromised and you need some help from your doctor or physical therapist to get back to normal.

You may feel that diagnostic studies are needed to get an accurate diagnosis of your condition. In fact, many people think that the MRI will show the doctor and physical therapist exactly what is wrong, and that he or she can then—and only then—prescribe the correct treatment. Not exactly.

What Diagnostic Tests Show

X-rays and MRIs are tools that can give your doctor a pretty good idea of the current state of tissues in your body. Do you have a broken bone? Is there a tumor present that needs immediate attention? Diagnostic studies can help rule in, or rule out, sinister lesions that need prompt fixing.

Diagnostic studies never tell your doctor or physical therapist exactly what to do.

Many orthopedic problems, especially the ones that seem to come on for no apparent reason, can be difficult to accurately diagnose. Even with very precise diagnostic tests, it can still be difficult to come up with an accurate diagnosis that can help your physical therapist treat you.

The Clinical Examination

Your physical therapist is trained to perform a thorough clinical examination when you first come in for therapy. He or she will measure your range of motion and strength, analyze your gait and posture, and get an assessment of your functional mobility.

The clinical examination will also reveal any areas of concern to your physical therapist that may signal the need for more advanced testing. For example, if you're having low-back pain and sciatica, and your physical therapist notices that you have foot drop﻿﻿ — a form of paralysis from compression of a nerve — he or she would (and should) notify your doctor of this serious finding. Advanced diagnostic testing may be necessary in this case to determine the cause of your foot drop, and to determine if more invasive procedures, like injections or surgery, are warranted.

A well-performed clinical examination by your physical therapist can help determine the correct treatment for you. It can also tell your physical therapist when something else may be causing your problem, and when physical therapy may not be the proper treatment for your condition.

Can Diagnostic Studies Be Harmful?

While most diagnostic tests carry very little risk, you should be aware of the possible side effects of these tests. An x-ray or CT scan does expose you to radiation, which may be harmful in large doses.﻿﻿ An MRI carries with it very little risk, but if you have any metallic implants or fragments in your body, you may not be able to have an MRI, as the magnet in the MRI may move the metallic objects in your body.﻿﻿ Be sure to discuss any and all diagnostic procedures with your doctor before proceeding to ensure that they are safe for you.

The Bottom Line

In general, you do not need advanced diagnostic tests like an X-ray or MRI before starting physical therapy.﻿﻿ If your pain or functional limitation came on gradually, or for no apparent reason, then your condition most likely does not warrant these tests right away, and it is safe to participate in physical therapy.

If your symptoms persist or worsen over a four-to-eight week period, then you should discuss your options with your physical therapist and doctor. An x-ray, MRI, or CT-Scan may be needed to help determine if there is something going on that is preventing your body from responding positively to physical therapy.

Remember, your physical therapist should perform a thorough clinical examination, and he or she is trained to recognize "red flag" signs and symptoms that may require you to check-in with your doctor to see if advanced diagnostic tests are needed to help determine the cause of your symptoms.