When Lower Extremity Dysfunction Contributes To Back Pain
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