"Physical therapy is not a subspecialty of the medical profession and physical therapists are not medical doctors; we are a separate profession that provides a unique service that physicians are unable and untrained to provide."

Letter to the AMA from the APTA, Dec 2009

Saturday, May 17, 2008

Regional Interdependence and Finding Normal

Regional interdependence is a concept familiar to physical therapists treating orthopedic conditions.

Regional interdependence is the following:
  1. finding hip involvement in patients with primary knee pain

  2. finding hip involvement in patients with primary low back pain

  3. finding thoracic involvement in patients with primary neck pain

  4. finding thoracic involvement in patients with primary shoulder pain

    (Wainner RS, Whitman JS, Cleland JA, Flynn, TW. Regional Interdepedence: A Musculoskeletal Examination Model Whose Time Has Come. JOSPT. Nov. 2007;37(11):658-660.)

With experience and training a physical therapist will often recognize patterns of movement that suggest regional interdependence. Wainner's article provides peer-reviewed evidence to support the concept.

While regional interdependence may come easily to orthopedic physical therapists, finding normal may not come easily.

For example, how many physical therapists can say to a patient these words...

"I've completely examined you and I can find no evidence of musculoskeletal invovelement. You are completely normal!"

Finding normal is important to regional interdependence because of the large number of potential musculoskeletal contributors to the primary complaint. For example, impairments in strength and range-of-motion at the hip and the ankle may contribute to primary knee pain.

Thomas Goetz writes in Wired Magazine about 'Finding Normal'.

He states the following...

"...we look not for causes of illness but for risks...But for all sorts of conditions , there's often no definition of normal."

Right now, the orthopedic physical therapy community is fascinated with trying to classify every patient into treatable sub-groups.

What happened to measuring patient characteristics and treating the findings?

I may be old-fashioned but I believe that the more you look for the more you find.

What gets measured gets treated.

Regional interdependence is a powerful concept that needs standards to guide physical therapists in making treatment decisions.

One technique that I'll offer up for public consumption and comment is this measurement that I use to assess hip external rotation.

I find that impairments in this motion (using this technique) often demonstrate hypermobile lumbar rotation.

Hip External Rotation measurement

Using data published on my website, I've found that this measurement correlates with functional limitations using the OPTIMAL scale. The correlation coefficient is 0.40.

I will often use this technique to stabilize a weak hip with primary knee osteoarthritis.

Patients with lumbar pain also respond well to strengthening the hip external rotators.

What's especially helpful though, when treating these conditions, I can test the hip external rotator muscles and, if the finding is normal, I can say to the patient the following:

"You are completely normal"


  1. Your blog keeps getting better and better! Your older articles are not as good as newer ones you have a lot more creativity and originality now. Keep it up!
    And according to this article, I totally agree with your opinion, but only this time! :)

  2. Thanks - this topic came up agian last week at the Running Medicine conference in Gainesville, Florida at


    Dr. Scott Greenberg has helped me with an article that I'll post on Evidence in Motion blog after CSM 2010 is over - probably Monday or Tuesday.



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Tim Richardson, PT owns a private practice at Medical Arts Rehabilitation, Inc in Palmetto, Florida. The clinic website is at MedicalArtsRehab.com.

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