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If the patient’s gait looks the same when they walk in without the orthotics as when they walked out, and we have made no visible positive effect on gait, then even if symptoms are masked there will be no long range change in function or form.
Elsewhere similar thoughts have been expressed.
Firstly:
I would be interested, from a visual gait analysis point of view, what others look for to determin if they think there is an improvement in the gait (meaning whole body involvement and not just feet).
Secondly:
how many of their senses people use to determin if they feel a persons gait has altered positively (i.e. sight / hearing etc)
For me, the actions of the feet, post orthosis fitting, play a part but, if i'm honest, a secondary one.
I would be interested, from a visual gait analysis point of view, what others look for to determin if they think there is an improvement in the gait (meaning whole body involvement and not just feet).
Visual gait analysis is an unreliable system for biomechanics assessment, it just gives qualitative data. If you want to see an improvement you will see it. It is a classical clinical assessment that gives you some guidelines about what the problem is.
Quote:
Originally Posted by Ian Linane
Secondly:
how many of their senses people use to determin if they feel a persons gait has altered positively (i.e. sight / hearing etc)
Sometime ago, after reading some posts on Podiatry Jiscmail mainly from Kevin Kirby and articles on different journals, I realise that kinematic approach to biomechanics assessment have lots of limitations. It is much better to think about moments instead of position.
I think visual gait analysis for measureing effectiveness of orthoses is not that important as we now know that it is an alteration of force/kinetic parameters that are associated with symptom reduction. So observing any movement/kinematic change does not necessarily mean anything.
I am not yet prepared to agree with Ed (I may or may not agree in the future) - we just have no evidence yet as to what is optimal kinematic/movement is and if there is an optimum and we achieve it with foot orthoses, is that associated with symptom reduction. ... it may or may not be. We do know that an alteration in the kinetic parameters are associated with symptom reduction.
Previously (and until very recently) I used to preach that a visual gait analysis only had one purpose: To look for any abnormal function that may be responsible for the symptoms that the patient has. The problem now is that we know its the force/kinetic parameters that are associated with symptoms, so you can not see these forces in a gait analysis without technology .... let alone know if we have modifed them in the right direction with foot orthoses.
More recently I have looked at some things that can be seen in a visual gait analysis using a digital video into computer that might correlate to some of the force parameters. We use SiliconCoach. There does appear to be 2 things that do correlate to force/time parameters measured by technology and, more importantly, do influence my orthotic prescirption decision making:
1. The position of the first met head during propulsion (see this thread)
2. The symmtry in timing of heel lift
As for gait analysis on issue of orthoses. IMHO, its a waste of time, unless technology (ie inshoe pressure measurement) is used to measure changes or not in the force time parameters with and withut the foot orthoses (and make final adjustments to the orthoses using this information).
I think visual gait analysis for measureing effectiveness of orthoses is not that important as we now know that it is an alteration of force/kinetic parameters that are associated with symptom reduction. So observing any movement/kinematic change does not necessarily mean anything.
I disagree here, Craig. Observing a change in kinematics in a patient also always indicates a change in kinetics since accelerations/decelerations cannot occur without a concomitant change in forces and/or moments. These changes in motion patterns of the foot and/or lower extremity with a foot orthosis may be due to one or both of the following factors:
1. The foot orthosis has altered the magnitudes, plantar locations, vectoral directions and temporal patterns of ground reaction force (GRF) that has, in turn, caused a direct change in kinetics across the joint axes of the foot and lower extremity during gait.
2. The foot orthosis has altered the magnitudes, plantar locations, vectoral directions and temporal patterns from GRF that has, in turn, caused an indirect change in kinetics due to the central nervous system changing the magnitude, temporal pattern and muscular recruitment pattern within one or all the muscles that mechanically affect the lower extremities.
Quote:
Originally Posted by Craig Payne
I am not yet prepared to agree with Ed (I may or may not agree in the future) - we just have no evidence yet as to what is optimal kinematic/movement is and if there is an optimum and we achieve it with foot orthoses, is that associated with symptom reduction. ... it may or may not be. We do know that an alteration in the kinetic parameters are associated with symptom reduction.
I do agree with Dr. Ed Glaser on this point: changes in the kinematics of gait are an important part of what we should be doing with our foot orthoses in many patients. Abnormal gait kinematics can cause injury simply due to the simple physics principle that a mass with a linear or rotational velocity has a kinetic energy (KE = 1/2 mv^2). If that body segment is moving too fast, or in the wrong direction at the wrong time, it also then has the energetic capability to cause injury to one of the structural components of the foot and/or lower extremity that is acting to absorb that energy of that abnormal motion.
For example, during running, if the patients foot strikes on the posterior-lateral border of the running shoe, with the center of pressure being lateral to the STJ axis at the instant of heel contact, this creates a STJ pronation moment that will tend to cause an internal rotation acceleration of the shank and thigh. After the initial impulse of GRF has occurred and the STJ pronation moments have been applied and the thigh and shank has accelerated with an increased internal rotation velocity, then this transfer of kinetic energy in the limb from a downward direction prior to heel contact to an internal rotational direction after heel contact must be absorbed and then transferred to energy elsewhere in the body by a set of anatomical structures. If, for example, the posterior tibial muscle is one of the primary structures used for absorbing this energy, and it is mechanically disadvantaged by short STJ axis moment arms or by being intrinsically weak, then it may be more likely to be injured by the repetitive absorption of kinetic energy caused by the STJ pronation moments that have caused the internal rotation kinetic energy of the shank and thigh segments. We should not assume the motion patterns of gait are not important for the simple reason that gait energetics are directly determined by motion patterns of the foot segments, lower extremity segments and other segments of the body. In other words, it is not all about kinetics!
Quote:
Originally Posted by Craig Payne
Previously (and until very recently) I used to preach that a visual gait analysis only had one purpose: To look for any abnormal function that may be responsible for the symptoms that the patient has. The problem now is that we know its the force/kinetic parameters that are associated with symptoms, so you can not see these forces in a gait analysis without technology .... let alone know if we have modifed them in the right direction with foot orthoses.
More recently I have looked at some things that can be seen in a visual gait analysis using a digital video into computer that might correlate to some of the force parameters. We use SiliconCoach. There does appear to be 2 things that do correlate to force/time parameters measured by technology and, more importantly, do influence my orthotic prescirption decision making:
1. The position of the first met head during propulsion (see this thread)
2. The symmtry in timing of heel lift
As for gait analysis on issue of orthoses. IMHO, its a waste of time, unless technology (ie inshoe pressure measurement) is used to measure changes or not in the force time parameters with and withut the foot orthoses (and make final adjustments to the orthoses using this information).
I cannot agree with you here, Craig. In my opinion, visual gait is only a waste of time if the clinician does not know how to properly perform a visual gait examination. I have been teaching visual gait examinations for over 20 years and for the busy clinician, it is absolutely indispensable. I perform about 20-25 visual gait examinations a day in my clinic and even though some of them tell me nothing, many of them allow me to determine the most likely cause of the patients mechanical/neurological problem and how I may best fix the symptoms and/or gait pathology that results from that problem.
Rather than going over the many points that I cover when I give my workshops on visual gait examination, I will attach a handout that I prepared for Ray Anthony's Biomechanics Summer School at Heythrop Park, England in the summer of 2004. I hope that proper visual gait examination techniques continue to be taught at podiatry schools around the world since it is the quickest, most efficient and least expensive method to analyze the kinematic effects of foot orthoses and shoes (and therefore also give a better idea as to the kinetic effects of foot orthoses and shoes) on the movements of the segments of the body during walking and running gait.
Quote:
In-Office Gait Evaluation
August 19, 2004, Oxfordshire, UK
Kevin A. Kirby, DPM, MS
In the science of applied mechanics, there are three branches:
Rigid Body Mechanics
Deformable Body Mechanics
Fluid Mechanics
In the study of rigid body mechanics, there are two branches:
Statics: Study of forces on rigid bodies at rest
Dynamics: Study of forces on rigid bodies in motion
In the study of dynamics, there are two branches:
Kinematics: Branch of dynamics that deals with the geometry and time-dependent aspects of motion without considering the forces causing the motion
Kinetics: Branch of dynamics that is based on kinematics and includes the effects of forces and masses on the body in question
(from Ozkaya, Nihat and Margareta Nordin: Fundamentals of Biomechanics: Equilibrium, Motion and Deformation. Van Nostrand Reinhold, New York, 1991, pp. 3-4).
Therefore, in-office gait evaluations are actually kinematic analyses of the patient performing the weightbearing activity that may be the etiology of their symptoms or pathology.
In doing a gait evaluation, what structures should have their movement patterns (i.e. kinematics) analyzed?
Feet
Lower extremities
Trunk
Upper extremities
Head
How should these motion patterns be analyzed?
Analyze in reference to what would be present in an individual with a normal gait pattern
Analyze in reference to history of presenting complaints of the patient
Analyze in reference to findings on physical examination
What is the best method to perform in-office gait evaluations?
Have the patient walk both barefoot and in shoes
Have the patient walk looking straight ahead, arms/hands in normal position
Have the patient walk at their normal walking speed
Make sure the clinic hallway is adequately illuminated so that accurate observations may be made
Method of clinical analysis of gait evaluation is important. Every gait evaluation should be performed in a methodical manner to ensure completeness by analyzing the following parameters in a stepwise progression:
Position and movement of head
Position, movement and asymmetries of shoulders
Position, movement and asymmetries of arms and hands
Position, movement and asymmetries of hips
Position, movement and asymmetries of knees
Position, movement and asymmetries of legs
Angle of gait
Base of gait
Position and movement pattern of calcaneus relative to the ground and leg should be noted during the stance phase of gait:
Contact phase
Early midstance phase
Late midstance phase
Propulsion
Position and movement pattern of the area of the foot inferior to medial malleolus in the medial midfoot should be noted since the area is a good indicator of talar head position
Talar head position is excellent indicator for spatial location of subtalar joint axis
Talar head movement indicates subtalar joint and midtarsal joint movement patterns
Important to note the timing of certain gait events:
Heel lift relative to heel contact of contralateral limb
Point at which maximum medial talar head position occurs during stance
Point at which maximum everted position of calcaneus occurs during stance
Propulsion should be classified according to length of time the forefoot is bearing weight without the heel on the ground
Apropulsive gait
Moderately apropulsive gait
Mildly apropulsive gait
Propulsive gait
Movement patterns noted during gait examination can be used to analyze possible physical cause of injury that is occurring in the structural components of the patient’s foot and lower extremity
Helps determine the abnormal forces and/or moments which may be causing the patient’s pathology or injury
Allows trial-and-error determination of optimum foot and/or shoe modifications necessary to establish more normal movement patterns of the foot, lower extremity and rest of the body
Allows clinician to observe and clinically quantify the functional result of therapeutic modalities such foot orthoses, in-shoe padding, taping, and shoe modifications
Allows clinician to observe and clinically quantify progression of healing from injury
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
You are right in that observing a change in gait will indicate that kinetics have changed. The point I am trying to make is that if you observe a change in gait with foot orthoses or not, then there is no relationship between that and if they respond clinically or not.
We do teach the students gait anlaysis, but also challenge with the question of what do you actually do with the information - very little of it is actually useful for deriving a foot orthoses prescription.
__________________
Craig Payne
Department of Podiatry
La Trobe University
Melbourne, Australia http://www.latrobe.edu.au/podiatry
__________________________________________________ ___________________________________ God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The views expressed above are those of the author and not that of La Trobe University This is where I am, where are you?
You are right in that observing a change in gait will indicate that kinetics have changed. The point I am trying to make is that if you observe a change in gait with foot orthoses or not, then there is no relationship between that and if they respond clinically or not.
We do teach the students gait anlaysis, but also challenge with the question of what do you actually do with the information - very little of it is actually useful for deriving a foot orthoses prescription.
Craig. The evidence suggests as you have pointed out, that orthotics don't change static measures etc. Am I right in saying that skin markers were used? Has anything been done radiologically? For instance xray with and without device?
Craig. The evidence suggests as you have pointed out, that orthotics don't change static measures etc. Am I right in saying that skin markers were used? Has anything been done radiologically? For instance xray with and without device?
Ron
It is incorrect to say that the research evidence shows that orthoses do not change the kinematics of gait. There is research evidence that orthoses do significantly change the kinematics of gait. However, if I were lecturing today on the subject, I would say that foot orthoses always change the kinetics of gait but often may produce immeasurable changes in the kinematics of gait.
Just because our instrumentation and measurement methods are not sophisticated and accurate enough to measure the motion changes that are occurring within the joints of the foot, doesn't mean it is not happening. Once we can reliably increase our measurement accuracy of the movement of the foot skeleton segments to within a fraction of a degree, then I predict we will be changing our tune and saying that foot orthoses do normally change the kinematics of gait.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
If I am not wrong, the original question was related to visual gait analysis (I understand this assessment as a clinician watching a patient walking without any tool a part from his/her eyes) for assessing foot orthotics outcomes.
I am with Craig about the poor reliability from this system for evaluating outcomes although it is an inexpensive system for achieving some qualitative data from patient's gait.
Quote:
Originally Posted by Kevin Kirby
It is incorrect to say that the research evidence shows that orthoses do not change the kinematics of gait. There is research evidence that orthoses do significantly change the kinematics of gait. However, if I were lecturing today on the subject, I would say that foot orthoses always change the kinetics of gait but often may produce immeasurable changes in the kinematics of gait.
Nigg B. Humble N. Stefanyshyn D. Orthotic Confort is related to Kinematics, Kinetics, and EMG in Recreational Runners. Med. Sci. Sports Exerc .2003, 35 (10) 1710–1719 8.
Quote:
Originally Posted by Ian Linane
I would be interested, from a visual gait analysis point of view, what others look for to determin if they think there is an improvement in the gait (meaning whole body involvement and not just feet)
Thinking again about this question and after reading Kevin's In-Office Gait Evaluation , I would response: gait asymmetries.
Nigg B. Humble N. Stefanyshyn D. Orthotic Confort is related to Kinematics, Kinetics, and EMG in Recreational Runners. Med. Sci. Sports Exerc .2003, 35 (10) 1710–1719 8.
Thanks for this reference, Javier.
Here are a few more scientific studies that show that foot orthoses do affect the kinematics of gait.
Running research:
Decrease in maximum rearfoot eversion angle (Bates et al., 1979; Smith et al, 1986; MacLean et al., 2005)
Decrease in maximum rearfoot eversion velocity (Smith et al., 1986; MacLean et al., 2005)
Decrease in maximum ankle dorsiflexion angle (MacLean et al., 2005)
Decrease in maximum internal tibial rotation (Nawoczenski et al., 1995; Williams et al., 2003)
Decrease in internal rotation and adduction of the knee (Stackhouse et al., 2004)
Walking research:
Decreased in rearfoot pronation and decreased rearfoot pronation velocity with varus wedged orthoses and increased rearfoot pronation with valgus wedged orthoses (Nester et al., 2001; Nester et al., 2003).
Decrease in rearfoot eversion during stance and decrease in internal tibial rotation after 12 months of wearing the orthoses in patients with rheumatoid arthritis (Woodburn et al., 2003).
References:
Bates BT, Osternig LR, Mason B, James LS: Foot orthotic devices to modify selected aspects of lower extremity mechanics. Am J Sp Med, 7:328-31, 1979.
MacLean CL, Hamill J: Short and long-term influence of a custom foot orthotic intervention on lower extremity dynamics in injured runners. Annual ISB Meeting, Cleveland, September 2005.
Nester CJ, Hutchins S, Bowker P: Effect of foot orthoses on rearfoot complex kinematics during walking gait. Foot Ankle Intl, 22:133-139, 2001.
Nester CJ, Van Der Linden ML, Bowker P: Effect of foot orthoses on the kinematics and kinetics of normal walking gait. Gait Posture, 17:180-187, 2003.
Nawoczenski DA, Cook TM, Saltzman CL: The effect of foot orthotics on three-dimensional kinematics of the leg and rearfoot during running. J Ortho Sp Phys Ther, 21:317-327, 1995.
Smith LS, Clarke TE, Hamill CL, Santopietro F: The effects of soft and semi-rigid orthoses upon rearfoot movement in running. JAPMA, 76:227-232, 1986.
Stackhouse CL, Davis IM, Hamill J: Orthotic intervention in forefoot and rearfoot strike running patterns. Clin Biomech, 19:64-70, 2004.
Williams DS, McClay-Davis I, Baitch SP: Effect of inverted orthoses on lower extremity mechanics in runners. Med. Sci. Sports Exerc. 35:2060-2068, 2003.
Woodburn J, Helliwell PS, Barker S: Changes in 3D joint kinematics support the continuous use of orthoses in the management of painful rearfoot deformity in rheumatoid arthritis. J Rheum, 30:2356-2364, 2003.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
Craig. The evidence suggests as you have pointed out, that orthotics don't change static measures etc. Am I right in saying that skin markers were used? Has anything been done radiologically? For instance xray with and without device?
Ron
The evidence is that some studies show they do change kinematics and other studies show they don't. I recently had a physio student in my office waving one of the studies showing they don't change kinematics, claiming orthotics don't work (....duh?) ---- the problem with all the kinematic studies is that regardless of the changes measured, none of them correlated that to symptomatic changes (we have the first one that does this in press at JAPMA).
There have been two studies that have measured x-ray changes while standing on foot orthoses and they showed changes ---- thats all well and good, but we do not know if the changes they measured are actually asscociated with better clinical outcomes or not. Most of the radiographic changes measured are linked to changes in arch height, but how desirable are those changes?
Another eg, its one thing to say that orthotic X reduced calcaneal eversion by 7 degrees and peak inversion moment by .14 Nm/bw.ht whereas orthotic Y reduced calcaneal eversion by 3 degrees and peak inversion moment by .24 Nm/bw.ht ---- what does that actually mean? which one is better? which change is associated with symptomatic improvement? .... we simply to not know.
Craig. The evidence suggests as you have pointed out, that orthotics don't change static measures etc. Am I right in saying that skin markers were used? Has anything been done radiologically? For instance xray with and without device?
Reinschmidt C. Three Dimensional Tibiocalcaneal and Tibiofemoral Kinematics During Human Locomotion Measured with External and Bone Markers.PhD dissertation Pge 2, University of Calgary, Dept Medical Science. 1996.
Concluded that skin surface markers over estimate change of position when compared to bone located marker pins.
Concluded that skin surface markers over estimate change of position when compared to bone located marker pins.
It makes sense, although skin markers are widely used for biomechanical assessment. For instance, Kevin Kirby and Simon Spooner used dots on the skin to identify the point at which the least amount of skin motion occurred:
Simon K. Spooner and Kevin A. Kirby. The Subtalar Joint Axis Locator: A Preliminary Report J Am Podiatr Med Assoc 2006 96: 212-219
Perhaps, they could explain more about the reliability from this system.
This thread is concentrating on the value of gait analysis. There are many important points to look at here, a few of which are.
1. Compare data from motion analysis to that gathered by the human eye.
a. The frame rate is better with motion analysis or high speed camera, and for research can be measured later to do statistical analysis and asses significance.
b. The human eye is free and you have it with you. The frame rate is about 15fps. Focus and depth of field are variable within biological limits.
2. The accuracy deemed necessary in any measuring device is proportional to the size of the changes being measured. Plus or minus a hammer handle is dead on when measuring the cosmos and absurd when measuring quantum effects.
a. In the past kinematic changes have been either small or nothing. The effect of orthoses on symptoms is being attributed to tissue stress changes. Certainly with great 3D motion analysis systems these changes are visible. The small changes being desired to be measured will require an equally accurate system to measure them. If you are measuring millimeters, you need a system that has a very small tolerance of error.
b. When I talked about changes is the gait cycle, I was talking about changes that are often dramatic and therefore easily visualized with the naked eye. In other words, where the eye is a perfectly unreliable instrument to measure kinematic changes with many cast corrected posted and skived orthoses, the eye does become a reliable indicator when changes reach a certain magnitude.
c. Certainly each patient will change their kinematics to a different degree. In other words, some changes in gait cycle, even with the most aggressive positional changes will appear to change little.
d. The smaller the change in gait cycle therefore, the less suitable the human eye is to measure them.
3. Conclusion:
a. For evaluation of orthoses whose primary action is to reduce tissue stresses and not change kinematics much, a very accurate system is necessary. Then do not trust visual gait analysis.
b. For evaluation of orthoses whose primary function is to change the kinematics of gait so that the foot never reaches the end of its ROM in the direction of pronation (where tissue stresses ocurr), which radically changes the COP in relation to the STJ axis by placing the foot in supination, the human eye is more suitable as a measurement tool.
But, what is it that you are looking for? Kevin did a good job in his outline. These are excellent visible parameters. I especially like the importance placed on symmetry. In fact I think that these would be very easily seen with a simple video camera which has a slightly higher frame rate than the eye but nowhere near that of a high speed camera. In fact this is an easy research study. (...hint...hint...)
BTW, we have a demo coming up of a high speed camera in the 6K range. Does anyone have one that they recommend?
I disagree with Craig on this point. Craig, you are still using alleviation of symptoms as the gold standard of success. I think not. I suggest a new standard: Restore Function because "form follows function". We need to reset the bar a little higher.
Bring the patient from their current gait cycle to as close to an ideal gait cycle as is possible with their anatomy. More ideal gait, in my observation leads not only to reduction in pain, but also to improvement or even reversal of many deformities.
Simon asked, what is ideal? I think that the Goals of Biomechanics that Don Bursch recommended in this post as follows is an excellent start.
Quote:
Originally Posted by Don Bursch
I propose the following as a general theory that might explain why almost anything put in the shoe as a corective insole has a positive effect on pain:
It is well understood in neuromusculoskeletal practice that almost any form of newly introduced, high intensity type II afferent stimulus will tend to block pain information from c fibers. So, for the short term at least, pick your favorite bump, put it under the richly innervated plantar foot, and watch the pain decline.
So if success is defined as a patient feeling better, no wonder so many can claim it.
Where a professional source of corrective insole should put themselves above the snake-oilers is the actual change in function that will alter the pathological tissue stresses that ultimately become deformity and pain. Ideally this should be observable as a positive change in gait but this tends to be very subjective. Research that can support these changes concretely is very difficult to do, unfortunately, given the state of our technology to image or measure them in a direct way.
I asked in another thread what the group might propose as the specific goals of biomechanical function, i. e. what are we trying to do with a biomechanical orthosis? I received one response: to reduce pain. Refer to the above to understand why I think this is not a good answer.
So here is my list of goals:
1. Sufficient re-supination of the foot occurs after midstance to stabilize or “lock” the tarsus in the sagittal plane to allow for efficient propulsion.
2. The forefoot contacts the ground without imposed abnormal compensatory motion proximally or in the transverse, sagittal or frontal planes
3. The first metatarsal is stably plantarflexed against the ground during forefoot loading
4. The first metatarsal accepts 60% of forefoot loading force
5. The first metatarsophalangeal (MTP) joint is free to dorsiflex sufficiently to avoid compensations in foot or lower extremity posture that would otherwise be necessary to allow sufficient dorsiflexion or forward gait progression
I would think that achieving these goals as much as possible is the way to insure long-term pain reduction, prevention of deformity and avoidance of surgical corrections.
In order to accomplish these, the foot must actually change in position and function. I have found that using full arch support with a thermoplastic shell that is the right mix of flexibility to allow some pronation but rigid enough to forcibly assist re-supination has been the most effective toward the above goals and for helping improve lower kinetic chain posture as well. I would like to see more research confirming what I see clinically, but this makes the most sense to me bio-mechanically.
I disagree with Craig on this point. Craig, you are still using alleviation of symptoms as the gold standard of success. I think not. I suggest a new standard: Restore Function because "form follows function".
I do not think we necessarily disagree...I just do not think we know what is the "ideal" function to restore people to is. Don's goals of
Quote:
So here is my list of goals:
1. Sufficient re-supination of the foot occurs after midstance to stabilize or “lock” the tarsus in the sagittal plane to allow for efficient propulsion.
2. The forefoot contacts the ground without imposed abnormal compensatory motion proximally or in the transverse, sagittal or frontal planes
3. The first metatarsal is stably plantarflexed against the ground during forefoot loading
4. The first metatarsal accepts 60% of forefoot loading force
5. The first metatarsophalangeal (MTP) joint is free to dorsiflex sufficiently to avoid compensations in foot or lower extremity posture that would otherwise be necessary to allow sufficient dorsiflexion or forward gait progression
may or may not be correct (from a theoretical standpoint, they sound OK), but we just do not know that if you do restore people to this theoretical norm, that outcomes (short and long term) are any better than if we did not restore them ....I think that is our point of difference. You may be right (or wrong) - there is just no data .....yet.
__________________
Craig Payne
Department of Podiatry
La Trobe University
Melbourne, Australia http://www.latrobe.edu.au/podiatry
__________________________________________________ ___________________________________ God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The views expressed above are those of the author and not that of La Trobe University This is where I am, where are you?
Concluded that skin surface markers over estimate change of position when compared to bone located marker pins.
Thats nothing compared to what we are preparing for publication. We measured the kinematic and kinetic changes to foot orthoses (for the purpose of using supination resistance as a predictor) .... as a side exercise we used difference reference frames (ie lab axis; foot axis; tibial axis; distal axis) and analysed the results seperately 4 times --- WE GOT A DIFFERENT RESULT DEPENDING ON WHICH AXIS WE USED ... ie we could pick one of the reference frames we used for publication to give us the result we most liked!!! - this puts a question mark over all previous studies, in that the choice of reference frame may have predetermined the resul!!!!
__________________
Craig Payne
Department of Podiatry
La Trobe University
Melbourne, Australia http://www.latrobe.edu.au/podiatry
__________________________________________________ ___________________________________ God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The views expressed above are those of the author and not that of La Trobe University This is where I am, where are you?
But, what is it that you are looking for? Kevin did a good job in his outline. These are excellent visible parameters. I especially like the importance placed on symmetry. In fact I think that these would be very easily seen with a simple video camera which has a slightly higher frame rate than the eye but nowhere near that of a high speed camera. In fact this is an easy research study. (...hint...hint...)
BTW, we have a demo coming up of a high speed camera in the 6K range. Does anyone have one that they recommend?
I disagree with Craig on this point. Craig, you are still using alleviation of symptoms as the gold standard of success. I think not. I suggest a new standard: Restore Function because "form follows function". We need to reset the bar a little higher.
Bring the patient from their current gait cycle to as close to an ideal gait cycle as is possible with their anatomy.
Nicely done, Ed. I agree with your statements above. In a previous Precision Intricast Newsletter from February 1999, (Kirby KA: Foot and Lower Extremity Biomechanics: Precision Intricast Newsletters 1997-2002. Precision Intricast, Inc. Payson AZ, 2002, pp. 3-4) I did a newsletter on the goals of foot orthoses. http://www.dpmlab.com/html/newsletter02.html
Here are my recommmendations from over 7 years ago that I still use today in my lectures on foot orthosis therapy:
Quote:
Goals of Foot Orthosis Therapy:
1. To reduce the pathologic loading forces on the injured structural components of the body in order to allow healing of the injured structures.
2. To prevent new injuries from occurring.
3. To promote more efficient dynamics of the body during weightbearing activities.
I agree with you, Ed. We, as foot-health specialists, should not stop short of only getting rid of the patient's symptoms when we make custom foot orthoses. We must also seek to optimize the gait function of our patients with our foot orthoses so that our patients will be able to derive maximum therapeutic benefit without having any new injuries or symptoms occur from our "foot orthosis gait optimization process".
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
I do not think we necessarily disagree...I just do not think we know what is the "ideal" function to restore people to is. Don's goals of may or may not be correct (from a theoretical standpoint, they sound OK), but we just do not know that if you do restore people to this theoretical norm, that outcomes (short and long term) are any better than if we did not restore them ....I think that is our point of difference. You may be right (or wrong) - there is just no data .....yet.
Craig,
Great point. Lets do the research. This year we are stepping up our research efforts considerably. We now have 5 cPeds on staff that are seeing patients and 80 employees we can measure. What I am most excited about is having Kinematic studies performed at an outside University comparing the various theories in all aspects and outcome measurements. Please suggest a design for the study at La Trobe and we will fund it, supply the Sole Supports and stay completely neutral in the evaluation of the data. Any other company or individual wishing to test their technology is more than welcome to participate by supplying thier product and hopefully some of the funding.
Craig, you are still using alleviation of symptoms as the gold standard of success. I think not. I suggest a new standard: Restore Function because "form follows function". We need to reset the bar a little higher.
Ed
Disagree Ed and Kevin.
Alleviation of symptoms should be the platinum standard.
Bring the patient from their current gait cycle to as close to an ideal gait cycle as is possible with their anatomy. More ideal gait, in my observation leads not only to reduction in pain, but also to improvement or even reversal of many deformities.
Thats nothing compared to what we are preparing for publication. We measured the kinematic and kinetic changes to foot orthoses (for the purpose of using supination resistance as a predictor) .... as a side exercise we used difference reference frames (ie lab axis; foot axis; tibial axis; distal axis) and analysed the results seperately 4 times --- WE GOT A DIFFERENT RESULT DEPENDING ON WHICH AXIS WE USED ... ie we could pick one of the reference frames we used for publication to give us the result we most liked!!! - this puts a question mark over all previous studies, in that the choice of reference frame may have predetermined the resul!!!!”[
Craig,
when you say different, can you say in what terms the results differed.
When investigating the limitations and errors of 3D Motion analysis I found that analysing the raw data in terms of varying axes would give less or more reliable output data.
This was because of the way that the camera system saw the limb markers relative to each other and the limb or joint of interest. Selecting the appropriate markers for the joint of interest and formulating the appropriate equations for analysis of the data would give the most reliable characterisation of the limb or joint motion.
Therefore analysis results can vary depending on the algebraic formulation used to manipulate the raw data and while one formulation gives reliable characterisation for a certain aspect it may not be so for a different aspect. So if the same processing is used for different reference frames then it may be that one would expect to have variable output data.
I use the word reliable because although the output data maybe accurate, and probably will be in terms of mathematical processing, it may not reliably characterise the joint motion in terms that are clear or useful to the clinician.
David - the details and mathematics of this are beyond me -- I leave that to the wiz I work with....this is his most recent email to me:
Quote:
investigating whether or not the responsiveness to orthotic intervention
(specifically the response of the invertor/evertor moment) is dependent
upon the choice of reference frame. My preliminary analyses suggests that
this may well be the case. Have attached data for you to look at:
- No discernable difference in ankle joint kinematics (not surprisingly)
- Reduction in peak invertor moment with orthotics. Note if change is
quantified as a % reduction from the "control (no orthotic) condition" then
the foot/JCS reference appears to show the greatest effect.
__________________
Craig Payne
Department of Podiatry
La Trobe University
Melbourne, Australia http://www.latrobe.edu.au/podiatry
__________________________________________________ ___________________________________ God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The views expressed above are those of the author and not that of La Trobe University This is where I am, where are you?
A ball dropped from a speeding train is seen by three people, one on the train 'A', the other two, B and C, on the ground but either side of the train .
A fourth 'D' party asks about the motion of the ball. A says it flew backwards toward B. B says it flew away from me. C says what ball?.
Imagine that A B and C are cameras looking at the marker Ball. You would have to write a formula so that the imformation given by the cameras would give a reliable characterisation of the motion of the ball. This would probably be in terms of a common reference point. Camera C, however would still give no infomation about the Ball. So you only use A and B's information to formulate the characterisation of the ball motion
Now drop the ball from the other side of the train and now the same formula has no information from B and does not use C therefore the data although accurate may not usefully characterise the motion of the ball and the characterisation may differ between the former and the latter.
Obviously this is very over simplified but I think it gives agood idea of the difficulties that may be experienced. The more sophisticated the collection and analysis system is the less these variations occurr.
However when changing reference frames, ie from a global frame of the lab to the local frame of the Femur, Then you have the problem of accurately locating the axis of the Femur. If you decide to reference from distal to proximal, ie from the foot axis to the shank axis then from the shank axis to the thigh axis etc, then each time there will be errors in terms of defining relative location of axis aswell as location of each axis in space. It would seem inevitable therefore that there may be considerable variation in output data when comparing two individual systems of reference.
Therefore your biomechanist may be saying the same in his/her report and it may be that great care should be taken when comparing these results in absolute terms.
No discernable difference in ankle joint kinematics (not surprisingly)
- Reduction in peak invertor moment with orthotics
When changing the analysis from global to local there will usually be a change in the internal moments since the extenal moments act about different lever arms. With regard to the STJ the invertor / evertor moments of the local axis in my limited experience they will usually be lower when comparing to global axis and in some cases will change direction. This should be independent of orthoses.
Let me answer Atlas and Javier at the same time. :)
Look at the knee. The knee is on the sagital plane (approximately) and acts like a hinge joint (a single axis). As the foot pronates, the knee internally rotates and moves mediallywhich increases the Q angle. This causes the Quads to pull laterally. The V shaped patella sitting in the V shaped femoral groove is pulled laterally by Quad contraction and rides up the lateral side of the groove and as it comes down, shears the medial 10-15000x/day and much more when running long distances. The shearing wears in infrapatellar cartillage on the medial side as one would expect.
Put this patient in posted orthoses and the kinematics are barely changed.
Put this patient in Sole Supports and the knee is in most cases on the sagital plane (the axis is perpendicular to the sagital plane). The muscle that was the deforming force, the quads, are now pulling the patella smoothly over the groove. Infrapatellar cartillage is replaced and the patient is better. Not just out of pain.
The standard treatment is strengthening the Vastus Mediallus (sorry about the spelling). This muscle cannot be isolated. You are really strengthening the quads. This in turn pulls the patella into the groove, which prevents it from riding up the lateral side of the joint and shearing the medial. The problem with this is that (and this is a secret)...some patients stop doing the exercises. The condition returns.
We have an opportunity to cure this condition. 70% of running injuries that stop runners from running are knee injuries and the vast majority are patello-femoral tracking disorder (a much better term than Chondormalacia Patella).
Can you see how only positional changes will have a real positive effect here. Covering symptoms can be accomplished with drugs. We can just give cortisone body whirlpools (a joke), but that will not change function. Do we just want to mask symptoms or change function? I say the later.
It makes sense, although skin markers are widely used for biomechanical assessment. For instance, Kevin Kirby and Simon Spooner used dots on the skin to identify the point at which the least amount of skin motion occurred:
On the contrary I was quite suprised by that. I would have thought that skin would move less than bone and that skin markers would underestimate the change of position.
Try this experiment. Put a mark on the positon of the apice of the greater trochanter with the hip in the position of reference. Internally rotate the hip and mark the greater trochanter again, externally rotate the hip and mark the apice of the GT again. You should find three different marked positions indicating that the bone traversed under the skin while the skin moved little.
If you were videoing the hip motion and using the first mark to estimate the position of the hip throughout the gait cycle it would not be possible to characterise its motion very reliably.
Let me answer Atlas and Javier at the same time. :)
Look at the knee. The knee is on the sagital plane (approximately) and acts like a hinge joint (a single axis). As the foot pronates, the knee internally rotates and moves mediallywhich increases the Q angle. This causes the Quads to pull laterally. The V shaped patella sitting in the V shaped femoral groove is pulled laterally by Quad contraction and rides up the lateral side of the groove and as it comes down, shears the medial 10-15000x/day and much more when running long distances. The shearing wears in infrapatellar cartillage on the medial side as one would expect.
Put this patient in posted orthoses and the kinematics are barely changed.
Put this patient in Sole Supports and the knee is in most cases on the sagital plane (the axis is perpendicular to the sagital plane). The muscle that was the deforming force, the quads, are now pulling the patella smoothly over the groove. Infrapatellar cartillage is replaced and the patient is better. Not just out of pain.
The standard treatment is strengthening the Vastus Mediallus (sorry about the spelling). This muscle cannot be isolated. You are really strengthening the quads. This in turn pulls the patella into the groove, which prevents it from riding up the lateral side of the joint and shearing the medial. The problem with this is that (and this is a secret)...some patients stop doing the exercises. The condition returns.
We have an opportunity to cure this condition. 70% of running injuries that stop runners from running are knee injuries and the vast majority are patello-femoral tracking disorder (a much better term than Chondormalacia Patella).
Can you see how only positional changes will have a real positive effect here. Covering symptoms can be accomplished with drugs. We can just give cortisone body whirlpools (a joke), but that will not change function. Do we just want to mask symptoms or change function? I say the later.
Ed
Ed, I like your thinking, and I too agree that the VMO retraining importance is over-blown. Physios think they have a bit of arsenal here, but its only a pop-gun.
But you have mis-understood what I mean by the goal of symptom-alleviation. Or rather, the means with which we get there.
I have placed altering foot mechanics to relieve symptoms at the top of the tree; rather than altering foot mechanics to achieve perfect textbook function.
Mechanical problems have mechanical solutions. I have never even thought about drugs/cortisone in relation to symptom alleviation.
Firstly, I agree that the symptoms are our immediate concerns (mainly because it is the patients), however prevention is a big part of our profession.
Secondly, if we are looking for a change in gait to or close to an "ideal" gait cycle, what is that ideal? This is the question Craig raises.
Don's goals below sound good but can they all be seen visually? What is "abnormal compensatory motion " in #2 goal? and so on.
HTML Code:
So here is my list of goals:
1. Sufficient re-supination of the foot occurs after midstance to stabilize or “lock” the tarsus in the sagittal plane to allow for efficient propulsion.
2. The forefoot contacts the ground without imposed abnormal compensatory motion proximally or in the transverse, sagittal or frontal planes
3. The first metatarsal is stably plantarflexed against the ground during forefoot loading
4. The first metatarsal accepts 60% of forefoot loading force
5. The first metatarsophalangeal (MTP) joint is free to dorsiflex sufficiently to avoid compensations in foot or lower extremity posture that would otherwise be necessary to allow sufficient dorsiflexion or forward gait progression.
Although we may not have any data to suggest positive outcomes for a particular "ideal gait" (I take Craig's word for it), would it be too simplistic for me to suggest that in theory the "ideal gait" would be the one that has the joints (whole body) functioning congruently (away from end range)? If a joint continues to function at end range it is more at risk of injury that the joint functioning away from end range.
Hard to visualise that too!
I just get the feeling that we are not paying enough attention to the whole gait. Yes we are getting great results from foot orthoses (distal correction) but are we ignoring some strong proximal forces. This is why I regularly send patients with orthoses to a physiotherapist who specialises in gait retraining(familiar with Irene Davis's work) and I think (haven't measured) that the"prevention" and the "efficiency of dynamics of the whole body during weightbearing activities" is enhanced.
Conp,
valid point about whole gait analysis. I believe overall posture has a very important role in evaluation too(which idea of course is not new - 'Gait and Posture' from elsevier has been published for a long time now.)
Kinematographic analysis lends itself well to wider analysis and I find it a useful tool in reviewing the efficacy of FFO's. ie. has it altered that antalgic hesitation, reduced the tib' rotation, decreased the kyphosis etc etc. I always show Pts the video as well, before and after, explaining what I'm trying to do, and what I think the FFO has accomplished.
That approach seems to get better compliance from the Pts for FFO's as well, if they have a basic understanding of the therapy and its goals.
Cheers,
Martin
__________________
Darn it Jim, I'm just an old country Chiropodist - not a miracle worker
thank you for the replies, very helpful thoughts and interesting.
I reached a point a while ago when I ceased relying to much on watching the foot to determin if any orthosis intervention I provided altered its function. Rather i have prefered to observe upper body changes in rotations and reciprical arm swing, postural alterations etc. Strangely, by looking more at altering overall gait/posture, whilst being aware of the presenting foot symptoms, I have found a helpful way of observing visually. I have to, for me, say that in most cases symptom resolution and altered gait posture have gone hand in hand (does not make it right of course). If I have got symptom resolution but not much alteration in gait/ posture I am happy anyway but also look to see if more can be done for posture etc.
It seems to work for me although it is a more gross observation than the fine ones of the foot. But for me it makes sense to take a whole view.
In this context I would suggest that visual gait analyisis is not dead. Possibly underated as we focus so much on fine movements of the foot?
Signs of gait improvement with foot orthotics
Linear Mode
