First MPJ ROM and foot orthoses

consideration on orthotic design during test.

Interesting study.

I know there can only be a small number of variables to a study but when these rearfoot control-1st mpj r.o.m tests are done there is no mention of 1st ray cast modification,terminal point of distal orthotic plate i,e bisection of 1st met head,or 1st/2nd interspace.etc Also 1st met or ray cut out?

If an orthotic in designed with a 4 degree varus post on the rearfoot,medial skive and medial flange you would naturally assume that the pronation moment will decrase and the supinatory moment in midstace will increase thus freeing up the 1st mpj to plantarflex and the halux to dorsiflex.Increasing the R.O.M at the mpj in the propulsive phase.

However if one of the following occured the 1st mpj R.O.M would be inhibited and reduced.

1)What position was the hallux in during casting?
2)How much plaster fill was added to to distal aspect of the 1st ray.
3)Was a forefoot supinatus mistaken for a forefoot varus and cast balanced inappropriately?
4)Where did the medial distal tip of the orthotic finish?
5)Was the distal medial aspect of the 1st ray portion of the orthotic ground down for asthetics(this would increase shell flex)
6)Was the shell thickness related to the patients weight?


Compare two devices.1)Rearfoot varus posted,medially skived,large medial flange,minimum arch fill proximally deep fill from forefoot balance platform extending the length of the 1st met shaft. Distal medial tip finishing 10 mm proximal to the 1st met head bisection and transversely between met 1 and 2

2) Rearfoot varus posted,medial skive,large medial flange,no arch fill.Orthotic shell finishing medial to the 1st met bisection and directly below the met bisection with little reverse bevelling of distal edge.

The difference would be minimal from heel strike to early mid stance but as device two had no plaster arch fill to the 1st ray and the medial tip finished too high and too medial 1st met plantarflexion would be reduced and hallux dorsiflexion reduced also.

Surely to have any true validity the exact deign of the orthotic device must be taken into consideration!

Perhaps this would make an interesting experiment,That is if it hasnt been done already.

scott

 

Scott:

These are all good points. Until researchers are much more specific regarding exact orthosis design prescription variables and patient selection criteria for those orthosis design variables, clinicians will need to continue to rely on trial and error and theory in regards to the mechanical effects of the thousands of orthosis design permutations that are available to them for their patients.

 

All,
In our study the dynamic effects of 5° varus and valgus rearfoot wedging on peak hallux dorsiflexion were investigated in 30 asymptomatic subjects (5 males and 25 females). Statistically significant reductions in peak hallux dorsiflexion were found with rearfoot varus wedging and rearfoot valgus wedging. Furthermore, the reduction in peak hallux dorsiflexion occurring with rearfoot varus wedging was statistically significant compared with that associated with rearfoot valgus wedging. (J Am Podiatr Med Assoc 94(6): 558–564, 2004)

 

The Relationship Between Navicular Drop and First Metatarsophalangeal Joint Motion
J Am Podiatr Med Assoc 96(4): 313–317, 2006

 

Congratulations to author,Jo Paton,
She is one of ours!!
Tony

 

From the latest issue of JOSPT:

Weight-Bearing Passive Dorsiflexion of the Hallux in Standing Is Not Related to Hallux Dorsiflexion During Walking

J. Halstead, A.C. Redmond

Study Design: Case control study.

Objective: To explore the validity of the assumptions underpinning the Hubscher maneuver of hallux dorsiflexion in relaxed standing, by comparing the relationship between static and dynamic first metatarsophalangeal (MTP) joint motions in groups differentiated by normal and abnormal clinical test findings.

Background: Limitation of motion at the first MTP joint during gait may be due to either structural or functional factors. Functional hallux limitus (FHL) has been proposed as a term to describe the situation in which the first MTP joint shows no limitation when non-weight bearing, but shows limited dorsiflexion during gait. One clinical test of first MTP joint limitation during standing (the Hubscher maneuver or Jack’s test) has become widely used in physical therapy, orthopedic, and podiatric assessments, supposedly to assess for the presence of hallux limitations during gait. The utility of the test is based on an assumption that restriction during the static maneuver is predictive of functional limitation at this joint during gait. Despite a lack of evidence for the validity of such an assumption, the outcome of the static test is often used to infer risk of overuse injury or as an outcome for functional therapy. This paper examines the validity of the assumptions supporting this widely used static test.

Methods and Measures: First-MTP-joint motion was assessed using an electromagnetic motion tracking system in cases (n = 15) demonstrating clinically limited passive hallux dorsiflexion in relaxed standing, and in 15 controls matched for age and gender and demonstrating a clinically normal Hubscher maneuver. Maximum hallux dorsiflexion was measured with the subject non-weight bearing (seated), during relaxed standing, and during normal walking.

Results: Hallux dorsiflexion was similar in cases and controls when motions were measured non-weight bearing (cases mean ± SD, 55.0° ± 11.0°; controls mean ± SD, 55.0° ± 10.7°), confirming the absence of structural joint change. In relaxed standing, maximum dorsiflexion was 50% less in cases (mean ± SD, 19.0° ± 8.9°) than in the controls (mean ± SD, 39.4° ± 6.1°; P<.001), supporting the initial test outcome and confirming the visual test observation of static functional limitation in the case group. During gait, however, cases (mean ± SD, 36.4° ± 9.1°), and controls (mean ± SD, 36.9° ± 7.9°) demonstrated comparable maximum dorsiflexion (P = .902). There was no significant relationship between static and dynamic first MTP joint motions (r = 0.186, P = .325).

Conclusion: The clinical test of limited passive hallux dorsiflexion in stance is a valid test only of hallux dorsiflexion available during relaxed standing. There is no association between maximum dorsiflexion observed during a static weight-bearing examination and that occurring at the same joint during walking. J Orthop Sports Ther. 2006; 36(8):550-556. doi:10.2519/jospt.2006.2136​

 

Nice work.

Makes sense mechanically when we use physics to model this. Y'all who don't believe that physics can be applied to biological systems may find this a bit more difficult to fathom though.

On the down side, the study tells us nothing about timing of dorsiflexion or kinetics required to achieve the dorsiflexion between the two groups.

Sagittal plane theorists would argue the the timing is key, tissue stressors, that kinetics is key.

 

You all, don't you know that the correct word is not "physics" but is "fizzicks" and can only be applied to dead people or Coca Cola?!! I mean, you should understand that when a live person weighing 70 kg is dropped from an airplane and their parachute fails to deploy and then hits the hard, unyielding flat surface traveling 36.0 m/sec that you cannot use "fizzicks" to calculate their kinetic energy at the moment of impact. However, if the person was first shot, killed and then thrown out of the plane and hit the ground traveling 36.0 m/sec that you could then use "fizzicks" to calculate their kinetic energy at the moment of impact with the ground!!

"Fizzicks" can only be used on dead things!! Everyone that learns their scientific knowledge and definitions from the internet knows that about "fizzicks"!! You all need to learn the real definition of "fizzicks" so that you can better understand the negative interactions of the dead human body with hard-flat surfaces.

 

Fizzicks


Cor blimey Kevin i would'nt want to take part in THAT clinical trial!! I have trouble getting ethical approval for handing out a questionaire!

Regards

Robert

 

Let's see, Simon's article showed a significant decrease in 1st MTP DF with varus and valgus wedges. Michaud and Nawoczenski showed the same thing in one patient (Simon what is the beta error on that?) Then in the conslusions of both papers it is stated that the decreased DF is a good thing? Except for trauma, I haven't seen too many Hallux Limitus patients complain of not enouth PF. It is usually DF limitation that is a problem.

What I get out of both of these papers is, if you want to increase 1st MTP DF grind off the post or wedge.

Ed

 

Apologies for my lack of knowledge, but could anyone expand on this point for me please?

 

Ed, it's not a good idea to say that an author concluded something, when he so didn't and also has the opportunity to show the rest of the readership of Podiatry Arena that he so didn't. This kind of spin may work on your website, but not here.

So here is the "conslusion" or conclusion as we called it from our paper in full:

"Conclusion
This study sought to provide further information about foot function and the management of foot pathology by evaluating the effects of 5 degree valgus and varus rearfoot wedging on peak hallux dorsiflexion at the first metatarsophalangeal joint. Within the limitations of the study, the results suggest that both forms of wedging had a statistically significant effect on peak first metatarsophalangeal joint dorsiflexion, with reductions occurring with both types of wedging. Furthermore a statistically significant difference was found when the effects of valgus and varus wedging were compared, with first metatarsophalangeal joint dorsiflexion more significantly reduced with varus wedging in place. These results may have implications for the clinical management of disorders of the first metatarsophalangeal joint, such as hallux limitus."

So exactly where within this do we state that "the decreased DF is a good thing?"?

This statement reveals a complete lack of understanding of our study (I can't make comment for the other authors). The word 'increase" here is great and demonstrates the mind of a genius/ salesman (you decide) at work.