I’m always amused when my (or any) profession comes out with a new term that essentially describes a concept that has been around for years. Regional Interdependence (RI) is one that has become quite popular in the physical therapy world over the past few years. It represents the idea that seemingly unrelated impairments in a remote region of the body may be associated with a patient’s primary complaint. Just listen to the old children song – The Skeleton Dance (the foot bone’s connected to the leg bone…) – and you’ll get the general idea. Truly, this is not a recent concept – only the terminology has changed.
It is an important concept to consider, however, when evaluating and treating almost all overuse running injuries. For example, research has confirmed how critical it is to assess hip mobility, strength, and function when trying to determine the cause for patellofemoral (kneecap) pain, as I’ve pointed out here on several occasions in the past.
Another common running ailment – plantar fasciitis (PF) – falls into this category as well. I’ve discussed this very prevalent injury 3 times over the past 30 years, most recently 10 years ago. At that time [Therapy Corner #99], I reviewed what was then the current evidence supporting or contradicting common treatments for plantar fasciitis, with most of them focusing on a very localized approach, using physical agents such as ultrasound or electrotherapies to treat the painful heel and/or, most commonly, prescribing foot orthotics, since the conventional wisdom says that an overpronating foot needs to be controlled to eliminate the stress causing tearing of the plantar fascia tissue.
These “clinical practice guidelines” for physical therapists were, in my opinion, very limiting and failed to examine all the possible causes for this injury to be discovered outside of the foot itself. The RI model, on the other hand, would take a more comprehensive, global approach in evaluating and treating PF and a recent case study published in Orthopedic Physical Therapy Practice illustrates its utility.
The authors of the article describe a 33-year-old male runner with a 6-month history of left heel pain that began after a gradual increase in weekly mileage. He had ceased running for a 6-week period and took anti-inflammatory medication, but when he resumed training at even half his prior mileage, the pain returned to its earlier intensity.
Symptoms and examination showed all the classic patterns for PF, including morning pain and an overpronation of the left foot (only!) during the stance phase of gait. His past medical history included an ankle sprain 4 months prior to onset and a herniated lumbar disc 3 years prior that left him with periodic low back pain Now, at this point, many providers would simply prescribe orthotics to arrest the excessive pronation and treat the heel with modalities and perhaps manual therapy, but in doing so would be ignoring these critical factors from his history that may have played a large role in causing this injury.
As I’ve noted many times in the past, the causes of overpronating feet are numerous and not limited to faulty foot structure that would call for an orthotic solution. In this case, it is absolutely critical to note that only his left foot showed excessive pronation. Unilateral overpronation is almost always a sign that the cause is to be found external to the foot itself; it is extremely rare to have only one foot have an abnormal bony configuration.
Knowing that, the authors considered what those causes might be related to his history. To briefly summarize their findings: (1) the prior ankle sprain caused a limitation of movement at that joint, resulting in overpronation of the foot to compensate, and (2) his previous low back injury resulted in neuromuscular weakness of key hip muscles that control excessive medial rotation of the entire lower limb, which in turn causes the same problem in the foot.
Based on this assessment, this patient was treated with manual therapy to restore normal ankle joint movements and lumbar spine mobility, and was given a home exercise program to maintain those improvements as well as foster normal movement patterns of the left lower limb during gait. Within one month his pain had decreased from 7/10 to 2/10 and a month later he reported no pain at all and was able to resume his weekly mileage to previous levels. No orthotic devices were prescribed during treatment. (He also reported a complete resolution of his low back pain.)
As I said at the beginning, Regional Interdependence is really just a newer, more impressive-sounding term for a concept that many therapists have employed for years. Unfortunately, not all healthcare practitioners do, and my purpose in describing this case study is to encourage you to be an educated consumer. For any running-related injury, you should be wary of anyone who fails to take a complete history; fails to consider the implications of that history; and fails to perform a complete examination of at least the entire lower extremities before simply zeroing in on, and treating, the injured area alone.