Functional hallux limitus and longitudinal arch flattening

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Those podiatrists that are subscribers to the sagittal plane facilitation model of foot function claim that functional hallux limitus (FnHL) causes longitudinal arch flattening. The notion seems to be that since the hallux doesn't dorsiflex in gait, the lack of hallux dorsiflexion then causes the forefoot to dorsiflex on the rearfoot.

What is very interesting is that when an arthrodesis is performed at the first MPJ, the medial longitudinal arch clinically becomes more stable and less likely to flatten during gait. It is amazing how well patients can function without a first MPJ that dorsiflexes during propulsion. I just had a 61 year old patient with a hallux rigidus deformity of only 10 degrees of hallux dorsiflexion finish the Ironman Triathlon in Hawaii, and he has a normal arch height.

It does not make sense to me that a lack of hallux dorsiflexion would cause medial arch flattening since the flattening of the medial arch will nearly always precede the propulsive phase of gait, when the demand for hallux dorsiflexion occurs.

Anyone else have other thoughts on this??

 

This may have slipped past me --- remember Chris Nesters presentation at PFOLA in Las Vegas 2 yrs ago that looked at the timing of "pronation" relative to the demand for first MPJ dorsiflexion ... my mind is a bit hazy (..remember I was not well at that mtg) on his results, but did it get published?

 

I do believe that Chris Nester's research got published but my brain is a little fuzzy on this one also. Maybe I'll find it in "the pile" in the next few days and get back to you on this one.

Good luck on Boot Camp with Bruce and Norman, Craig. Sounds like a good meeting and am interested in Sally's ankle joint stiffness lecture.

 

published paper

Hi,

would it be possible for you to send me information on the published article you have mentioned in your thread. I am currently working on assignment on functional hallux limitus with reference to the sagittal plane facilitation model of foot function against Root's theories. Any information would be greatly be appreciated.
lorraine. confused student

 

As I recall, Chris initially suggested that the FN hallux limitus preceeded the arch flattening, but then Kevin tutored him in the ways of the force and they both locked themselves in Kevin's room for a while and upon their return Chris had seen the light

 

Lorraine you be a confused student because you don't read. If you had read the original postings of Kevin and Craig you would realise that the work was not published. Students don't you just love em.

 

That'll teach me to read. Kevin, did actually say he thought it was published. Sorry Lorraine. PhD podiatrists, don't you just love em.

 

Basketball and British Podiatrists

If I remember correctly, when Simon Spooner visited my house a few years ago to do some research on the subtalar joint axis locator (the research from this visit will be published in JAPMA in a few months), he couldn't wait to demonstrate to me his "form" in attempting to shoot some hoops in my front driveway basketball court. This is where I learned that Simon had obviously played much more rugby than basketball during his formative years.

I don't know what the odd fascination is with a basketball hoop with these British podiatrists, but it has been a veritable magnet for the likes of Dr. Simon Spooner, Dr. Chris Nester and Ray Anthony when they have visited my house. I can only assume that they have all been deprived during their youth of adequate basketball hoops in their mother country. Therefore, my hypothesis for the reason why they won't leave you alone until you hand them a ball to try and shoot some baskets when they first arrive for a visit at your house with a basketball pole on the side of the driveway is that they must have been deprived in England of such an experience. Don't you British podiatrists have any basketball courts in your country??

 

Kevin,
We all just like to let you demonstrate Newtons Laws of Motion to us and tutor us in the ways of the force, the obvious tool being the b.ball. "He" would have used an apple, but when in Rome...

 

Dear all,

Too bad, but the results of our study (with Howard Dananberg as co-author) about the influence of structural or functional hallux limitus on plantar foot pressure and 1st MTPJ function in gait is only accepted for publication so far and thus not yet published in JAPMA.

Our results indicate that about 20% of the subjects showing structural or functional hallux limitus seem to show midtarsal pronation as a retrograde phenomenon, thus occurring after heel lift (midtarsal pronation here is measured by navicular drop) and possibly being a result of a hallux limitus condition.
However, not all subject demonstrating a retrograde midtarsal pronation showed a hallux limitus, structural or functional. This seems to imply that retrograde midtarsal pronation, may be due to other conditions than hallux limitus too.

Hope this may shed some light.
Sorry for the ones wanting more info. Keep an eye on JAPMA and you'll be rewarded.
Regards,
Bart

 

Thanks Bart - will look out for it

That not inconsistent what we found in our study - the sensitivity and specificity was OK, but not good:
Craig Payne, Vivienne Chuter, and Kathryn Miller: Sensitivity and Specificity of the Functional Hallux Limitus Test to Predict Foot Function J Am Podiatr Med Assoc 2002 92: 269-271

 

Bart:

Thanks for giving us a preview of your study with Howard. Howard and I are going to be doing a lecture together (point-counterpoint type lecture) at the APMA Annual Meeting in Las Vegas in August. Each of us will discuss the biomechanics of hallux limitus, from our own viewpoints, with the title of the lecture being: "Managing Hallux Limitus: Improving Treatment Results by Understanding it Etiology and Biomechanical Effects".

I would like to point out, regarding your research with Howard, that since only 20% of the subjects with functional hallux limitus (FnHL) showed midtarsal joint pronation after heel off, then there were relatively few subjects in the study where the functional hallux limitus could have caused midtarsal joint pronation. My opinion, as you probably know, is that FnHL is not the cause of pronation but rather is the result of late midstance pronation in association with a lower than normal medial arch height. These factors increase the tensile force in the plantar aponeurosis which, in turn, increases the 1st MPJ plantarflexion moment to such a large magnitude that the 1st MPJ dorsiflexion moment from GRF at heel off can not dorsiflex the hallux. Your research seems to support my claim that FnHL does not cause late midstance pronation since you found that four times more subjects with FnHL did not demonstrate midtarsal joint pronation during propulsion than the subjects with FnHL that did demonstrate midtarsal joint pronation during propulsion.

Feet that have decreased forefoot dorsiflexion stiffness will be more likely to have FnHL since they will tend to have more longitudinal arch flattening in late midstance than those feet with increased forefoot dorsiflexion stiffness. As we learn more about the foot, I believe that FnHL will be found to simply be the result of decreased dorsiflexion stiffness of the forefoot, especially medial forefoot, since this mechanical characteristic of the foot would tend to cause excessive longitudinal arch flattening, increased plantar fascial tension and increased 1st MPJ plantarflexion moment.

By the way, Bart, I am very glad to have you contributing....just like old times.