Offering biomechanical insights on how back pain may be triggered by secondary postural changes and altered gait compensations from foot dysfunction, this author emphasizes assessment of the sagittal plane and a better understanding of the impact of lumbar spine flexion.
Consider that individuals walk anywhere from 2,500 to 15,000 steps per day.1 If any one of those individuals has a biomechanical foot dysfunction, the resulting abnormal movement and function can and will alter gait, putting stress and strain on muscles, bones and joints in regions of the body remote to the foot.
When this altered gait is repeated day after day, week after week and year after year, it ultimately weakens muscles and joints, causing pain, arthritis and increased susceptibility to injury.
As the decades pass and podiatric biomechanics is seemingly better understood, the significant influence gait abnormalities can have on musculoskeletal symptoms and dysfunctions in the proverbial “kinetic chain,” as a result of secondary postural changes, becomes more apparent. No longer should we isolate our thinking to the pathological effects these gait abnormalities create within the foot. We also need to consider the effects of these gait dysfunctions proximal to the foot.
Indeed, foot dysfunction may be the etiology or a contributing factor in many pathological conditions, including those affecting the back, hips and knees as well as other joints, bones and muscles. As a result of these postural changes, there is subsequent redistribution of ground reactive forces and the forces altered and redirected via compensations and the repetitive movements involved in gait.
If a patient has a condition (i.e. a painful lower back) proximal to the foot and it is aggravated during or after walking or standing, that may be a good indicator that foot dysfunction is the cause or a contributor to the problem. If this is the case and there are obvious podiatric biomechanical dysfunctions (even in the absence of pain in the feet), one can prevent serious conditions from developing proximally in the kinetic chain. If these serious conditions are already present, the use of appropriate podiatric biomechanical treatment can help manage these conditions, alleviate pain and provide an environment to prevent further deterioration in these regions.
Although this article may be subject to controversy among some of my peers, I write from a perspective of 18 years of experience of using podiatric biomechanical means to eliminate or reduce low back pain in patients to the point where their lives and activities were restored to an acceptable level and often to a non-problematic state.
Why Back Pain Treatment Fails And Where Foot Dysfunction Fits Into The Picture
Recent statistics revealed that low back pain and dysfunction in the United States was in excess of a $60 billion industry.2 More astounding were other statistics that indicated that 71 percent of all low back surgeries failed.2-3 In fact, an ICD-9 code for “failed back surgery” was created. Interestingly, the 29 percent of individuals who had initial success with their back surgery often began having some level of symptoms again within the first 14 months after their surgery.2-3
What perpetuates some of the failures seen in the treatment of low back conditions? One, back surgeons may not be aware of the possibility of lower extremity biomechanical causes of back pain. Secondly, I think traditional medical thinking has developed into a paradigm in which we see more treatment of symptoms and test results rather than treating people and their conditions. Lastly, I think we often treat our podiatric patients that have biomechanical disorders by directing foot motion in the incorrect plane needed in particular cases or by using corrective posts that may be stabilizing the wrong plane, thereby often creating a wonderful supportive environment but a less than optimal movement environment for their given condition.
In my experience, I have found that back pain responds favorably with appropriate podiatric biomechanical care in a large number of patients. In fact, I think that most low back dysfunctions that are not caused by a congenital back abnormality or a substantial local injury — falling out of a moving truck or some other significant event causing a truly localized traumatic episode — are the result of walking dysfunction. Another scenario is the patient who has had a previous, legitimate, traumatic injury to his or her back that never seems to heal or dissipate. This may be the result of a walking dysfunction that interferes with the recovery of the injured area.
Dananberg published a study involving patients who were considered to have “end-stage” low back dysfunction.3 He found that the use of appropriate orthoses either improved their back pain by 84 percent or lead to them being pain-free, and they were able to maintain those results. There is a known 71 percent recurrence rate at 12 months (for those who had back surgery). The results were equally astounding considering those patients had symptoms for years and had previously been treated with various modalities, including surgery.
When you consider these statistics and study findings, it seems that a significant number of low back dysfunctions may have been caused by foot dysfunction.2,3 Dananberg’s study also suggests that many back conditions may be caused or influenced by “repetitive motion” of abnormally functioning feet, resulting in secondary gait-related postural compensations responsible for the low back pain.3 Dananberg’s study also suggests that patients who had injuries to their backs 20 to 40 years ago, as some of those who were included in the study, were likely not getting better because their repetitive dysfunctional gait disturbances had not yet been addressed.3
Emphasizing Assessment Of The Sagittal Plane
Getting back to the point about treating test results rather than patients, we often see findings on X-rays and MRI studies that seem abnormal but are in fact incidental findings that are revealed during the course of evaluating the patient for a different condition. Additionally, is it reasonable to question some of the findings observed on these imaging studies, particularly when it comes to backs, if they are done with the patient recumbent — as patients usually are with MRIs — when in fact their symptoms often only occur during standing, walking and/or sitting?
So, ultimately, what is the real value of these imaging findings? Additionally, how many patients do you see who have normal tests but significant symptoms? This is not necessarily uncommon in many people with low back pain. Many people with low back pain often see many different practitioners and have various tests performed, often resulting in no significant findings. I have seen many of these types of patients and what they generally have in common are podiatric biomechanical dysfunctions, particularly those dysfunctions that involve limitations of motion in the sagittal plane.
With all of this said, I think one needs to consider the value of evaluating and treating this type of patient from a podiatric perspective. How should we evaluate gait and what do we need to treat in order to alter the gait pattern in such a way to facilitate a positive effect on movement and the proximal structures in the kinetic chain?
First, I think it is important to consider that the major plane of movement in walking is, in fact, the sagittal plane. More than 80 percent of gait should be sagittal plane movement. Is this something most podiatric practitioners generally consider when they treat patients biomechanically? If so, why does it seem that so many of the orthotic corrections prescribed for patients in the podiatry community get applied for frontal plane stability or at least as frontal plane corrections?
Of course, this is the area I suspect will create some controversy as it also brings up the idea of motion controlling orthoses versus motion enhancement orthoses. These two different ideas of course are a topic for a different discussion.
Certainly, when we watch patients stand and walk in a traditional setting (i.e., a hallway), the frontal plane deformity is the most obvious to assess and ascertain information about. However, are those findings merely demonstrations of sagittal plane compensations? If so, are we then only treating the symptoms that result from the sagittal plane pathology and not the pathology itself?
It is easy to believe what we can readily see in our standard environments of examination. After all, many of our patients report feeling better so it becomes even easier to believe the treatment must have been correct. Certainly, one can consider that any increased foundational stability created (i.e. frontal plane corrections) can and often will positively influence certain activities such as standing, or those activities that do not require a lot of movement and can therefore take stress off of the back through obtaining a more static structural alignment.
However, is this also the best way to properly enhance repetitive physical motion in a closed kinetic environment and treat the podiatric biomechanical dysfunctions that may actually be the true source of the pathology influencing the back dysfunction in the first place?
Certainly, another approach is considering more of what is happening in the sagittal plane. That, after all, is the predominant plane of walking movement and may potentially be the etiological trigger of lower back dysfunction. If this is the actual or major contributing etiology to back pain and dysfunction, treatment lies in addressing that plane of movement more thoroughly.
Understanding The Impact Of Lumbar Spine Flexion
When considering back pain, it is important to consider what can destabilize the back. Flexion of the lumbar spine appears to have the most potential for damaging effects. If the lumbar spine flexes during gait, the vertebrae flex forward, the posterior vertebral facets disengage and the intervertebral discs become compressed anteriorly, thereby encouraging them to extrude posteriorly.
If these factors are combined with a leg length discrepancy that is in play during movement, this will often shift the destabilized disc more unilaterally. Certainly, a unilateral sagittal plane dysfunction can also cause a back problem to be more one-sided. These situations all cause axial rotational torquing forces that ultimately create significant localized muscular overuse and ultimately disc damage. However, this discussion is beyond the scope of this article.
At the point of the aforementioned compensatory flexion, the hip extensors will fire in an attempt to stabilize the spine by trying to reverse the abnormal flexion. This attempt for muscular stabilization to stabilize the axial skeleton and intervertebral discs may result in muscular tightness or spasm, which is probably the first symptom that back pain patients will experience.3
Making this scenario more problematic is that the lower extremities in an adult account for approximately 15 to 20 percent of one’s total body weight.3 The lower extremities are primarily attached anteriorly to the L1-L4 vertebrae and their intervertebral discs via the iliopsoas muscle complex. When the low back and hip on the stance limb is in early flexion in the gait cycle, as a result of a sagittal plane blockage or disturbance, this negates the normal and effortless forward swing of that limb. This early flexion subsequently creates a need for the lower extremities to be lifted and carried forward, thereby demanding the assistance of the iliopsoas complex, creating a 15 to 20 percent body weight load on the destabilized low back.
Over time, this “repetitive motion” of lifting and moving this weight load on the low back yields injury to the unstable discs as I previously described. This torsional load also extends to the L4- L5 level due to the abnormal rotational forces and muscles involved when the hip flexes.
So what causes the early lumbar flexion that results in this repetitive damaging cycle?
A Closer Look At Sagittal Plane Pivots And Kinetic Chain Flexion
In an attempt to appreciate and accept this conceptually, one has to consider a broader and perhaps more simple understanding of what occurs during walking.
Dananberg has offered the scientific and research basis for this discussion in many peer-reviewed articles that thoroughly explore and explain these sagittal plane concepts in detail.4-10 Murphy has also been instrumental in teaching these and other contributing aspects relating to physical movement, demonstrating their biomechanical influences on damage in and about structures proximal to the foot.12-14
Essentially, one needs to appreciate that the foot should move through three distinct pivots in each individual gait cycle. The first pivot is rolling over the heel itself after heel strike. The second pivot is ankle dorsiflexion that causes the heel to lift off the ground and the final pivot is the movement over the MPJs with the hallux being passively stable on the weightbearing surface via the first MPJ flexor stabilizing mechanism. These are essentially the three pivots of the foot in one gait cycle, which enable the body to pass over the unobstructed passive stance limb.
Anything that blocks or slows down any one or combination of these pivotal events will cause a disruption in the closed kinetic chain. Perhaps the most important event that takes place is a generalized kinetic chain flexion. If the pivot or pivots I have described above are not working or are retarded in their speed of motion relative to the acceleration of the rest of the body in motion (which is a result of most sagittal plane blockades or dysfunctions), kinetic chain flexion occurs and this will slow down the forward motion of the accelerating body passing over the passive stance limb.
This flexion goes up the entire kinetic chain, including the knee, hip, lumbar spine and cervical spine. All of those regions become destabilized when flexed. Stability is present in the passive weighted parts and axial skeleton when the joints are extended and not flexed. When there is flexion, movement slows in the affected loaded structures, increasing force on those structures as a result of “force over time.” Damaging torque is also increased in these flexed structures due to abnormal rotational forces that occur due to the flexion and improper muscle recruitment via compensations.
There are many conditions that can interfere with the sagittal plane pivots. They include but are not limited to:
• functional hallux limitus
• structural hallux limitus
• pseudoequinus/functional equinus/anterior cavus
• limited ankle joint dorsiflexion with the knee extended
• ankle osseous equinus
• pain in the midfoot or forefoot
• knee derangement
• hip arthritis
Any of the aforementioned conditions or any combination of those conditions can disrupt (block or slow down) any or all of the three sagittal plane pivots in the gait cycle. As I previously indicated, this will cause flexion of the body parts (including the lumbar spine) that are proximal to the foot and can cause or contribute to low back dysfunction and pain as I have described above.
Underscoring The Value Of Video Gait Analysis
Certainly, one can evaluate these conditions in conventional ways but the use of slow-motion videography — particularly when viewing from the sagittal plane — is invaluable as is utilizing in-shoe pressure mapping analysis such as F-Scan®.15-17 Being able to assess force versus time, center of force (COF), COF trajectories, timing delays and asymmetries between feet are enormously valuable in prescription writing for orthoses.15,16,18,19
These modalities allow the function of the sagittal plane to become very apparent. One is able to see dysfunctions that one cannot visualize via conventional examinations or watching patients walk in hallways. These additional evaluations yield data that often change one’s thinking about orthotic prescription writing as the podiatrist can obtain a host of new information in addition to the info from traditional models of examination.
By expanding one’s scope of evaluation, taking a fresh look at podiatric biomechanics in this way and working to mitigate the deficiencies that prohibit the appropriate sagittal plane pivot(s), one can consider and utilize many corrections and/or combinations thereof, depending on the clinical evaluation and diagnosis for the patient in question. These corrections and modifications can include but are not necessarily limited to:
• heel lifts (symmetrical and asymmetrical)
• kinetic wedges
• bidirectional first ray cutouts
• long first ray cutouts
• wide first ray cutouts
• combinations of first ray cutouts (hybrids)
• first metatarsal “grooves” in the shell of the orthotic device
• angled forefoot and/or rearfoot postings (oblique postings)
• frontal plane postings for COF “redirection” rather than for deformity support
• frontal plane postings to encourage “offloading of proprioceptors,” attempting to redirect the foot in motion
• compensation for leg length differential
In conclusion, I think podiatric practitioners should be looking closely at patients with complaints of low back pain and carefully assess their walking mechanics. It is imperative to assess movement difficulties and dysfunctions in the sagittal plane when evaluating and treating these particular patients. The results of eliminating podiatric biomechanical dysfunctions through appropriate orthotic treatment, particularly when addressing abnormal conditions in the sagittal plane, can yield remarkable results for the patient with low back dysfunction.
Dr. Trachtenberg is in private practice in Vestal, N.Y. He specializes in video and computerized gait analysis to evaluate the postural effects of abnormal walking that can lead to disorders affecting the knees, hips, back and other related musculoskeletal dysfunctions. Dr. Trachtenberg is a Fellow of the American College of Foot and Ankle Surgeons, and a Diplomate of the American Board of Podiatric Surgery.
1. Dananberg HJ. The Effect of Gait on Chronic Musculoskeletal pain. Manual for The Langer Foundation for Biomechanics and Sports Medicine Research, 1992 pp.16-22.
2. Seminars with Howard Dananberg, DPM.
3. Dananberg HJ, Guiliano M. Chronic low back pain and its response to custom foot orthoses. J Am Podiatr Med Assoc. 1999;89(3):109-17.
4. Dananberg HJ. Gait style and its relevance in the management of chronic lower back pain. In: Vleeming A, Mooney V, Gracovetsky S, Lee D, et al. (eds): Proceedings, 4th Interdisciplinary World Congress of Low Back & Pelvic Pain, Montreal, Canada, November 8-10, 2001, pp. 225-230.
5. Dananberg HJ, Guiliano M. Gait mechanics and their relationship to lower back pain. In: Vleeming A, Mooney V, Tilscher H, Dorman T, Snijders C. (eds): Proceeding of 3rd Interdisciplinary World Congress on Low Back and Pelvic Pain. European Conference Organizers, Rotterdam, Holland, November 1998.
6. Dananberg HJ. Gait style and function of the SIJ. In: Vleeming A., Mooney V, Snijders C, Dorman T (eds): Movement, Stability, and Lower Back Pain. Churchill Livingstone, New York, 1998, pp. 253-267.
7. Dananberg HJ. Lower extremity pathomechanics and its effect on sacroiliac function. In: Dorman T (ed): Spine—State of the Art Reviews, Prolotherapy. Hanley & Belfus, Philadelphia, 1995, pp.389-405.
8. Dananberg HJ. Gait style as an etiology to chronic postural pain. Part II. The postural compensatory process. J Am Podiatr Med Assoc. 1993;83(11):615-24.
9. Dananberg HJ. Gait style as an etiology to chronic postural pain. Part I. Functional hallux limitus. J Am Podiatr Med Assoc. 1993;83(8):433-41.
10. Lawton M, Dananberg, HJ. Functional hallux limitus and chronic musculoskeletal pain. Abstract. J Phys Med Rehab. November 1991.
11. Murphy N. Pressure profiles and force assessments to treat biomechanical foot and gait related disorders. Congress Proceedings 2010 World Congress of Podiatry, Amsterdam, Netherlands, May 13-15, 2010.
12. Murphy N. Murphy 4P method for F-Scan® systems. Manuscript. Tekscan, Inc., Boston, 2006, pp. 22.
13. Murphy N. General foot function & gait analysis using the Murphy 4P method with F-Scan®. Clinical case study manuscript. Tekscan, Inc., Boston, 2005, pp.1.
14. Murphy N. Improving asymmetry during gait using the force-time graph in F-Scan®. Clinical case study manuscript. Tekscan, Inc., Boston, pp.1.
15. Trachtenberg G. Great gait. How mapping technology can analyze gait & provide data to help restore normalcy. Advance Phys Ther Rehab Med. 2010;21(20):23.
16. Trachtenberg G. Enhanced foot function and gait analysis using the 3Box approach with F-Scan®. Educational monograph. Tekscan, Inc., Boston, 2005.
17. Trachtenberg G. Using video to complement F-Scan® data. Educational monograph. Tekscan, Inc., Boston, 2005.
18. Trachtenberg G. Using F-Scan® to evaluate orthotic prescriptions, orthoses and orthotic labs. Educational monograph. Tekscan, Inc., Boston, 2005.
19. Trachtenberg G. Using F-Scan® with or without “test orthoses” for orthotic prescription writing. Educational monograph. Tekscan, Inc., Boston, 2005.
Editor’s note: For further reading, see “When Orthotics Can Treat Low Back Pain” in the April 2003 issue of Podiatry Today, “A Closer Look At Case Studies In Gait Analysis” in the August 2005 issue or the DPM Blog “Can A Shoe Lift Ease Back Pain From CAM Walkers?” at http://tinyurl.com/atp6vgo .