Rootian casting technique

[robertisaacs]

Greetings Y'all.

Ahhh students. You love em. And you hate em. But they do make you think and ask searching questions. Specifiaclly about routian casting docterin.

So you are there with your plaster o paris and you bowl and your apron lookin' sharp and proper. You slap the plaster on in the proscribed manner. Now here it gets ticklish.

I am reliably informed that you find STN at the talar heads to get the rearfoot into STN (we shall, for the time being, leave aside the question of whether this is the right thing to do or not).

You then load the lateral column by applying upward force under the 4th / 5th met heads to hold the " midtarsal joint in its maximally pronated position"

_{ROOT ML, WEED JH, ORIEN WP: Neutral Position Casting Techniques, Clinical Biomechanics Corp, Los Angeles, 1971}

Other modifications are indicated if the forefoot cannot be made perpendicular to the rearfoot in this way. Lets leave those to one side for now.

Now, some questions for those among us who are handy with the POP.

If the maximally pronated position of the mid tarsal joint puts the forefoot in valgus relative to the rearfoot what then? Does one hold the forefoot in a less than maximally pronated position In order to maintain STN or does one adjust the rearfoot to a varus position?

The position of the STJ during Gait in a "normal" foot is a matter for some debate.


Note that Mc poil and Wessel both suggest that the STJ is maximally pronated, or not far from it when the forefoot loads. This would suggest to me that when in mid stance (when the foot is receiving GRF from both the rear and the forfoot and therefore the Midfoot angle is being controlled most by the insole) The forefoot (in a "normal" foot) will be in its most SUPINATED position. What gives with the maximally pronated position game.

The rootian technique talks about the "position of maximum Functionality". The rootian STN insole is classically referred to as a "functional" insole (which , BTW, causes my BP to rise 10 points just typing it.)

If the STJ is most pronated when the forefoot loads it would suggest to me that the rearfoot will be maximally supinated at this point. If that is the case, in the "normal" foot, how can the position of maximum functionality be at the diametric opposite of the "normal" foot.

I am not unaware that the windlass will have a pronatory effect on forefoot. However at what point does the windlass kick in. A quick literature search revealed nothing overly concluesive, I'm certain dave could tell me. A brief scan of the refs in _{Function of the Windlass Mechanism in Excessively Pronated Feet
Anna Aquino, BPod(Hons)* and Craig Payne, DipPod(NZ), MPH Journal of the American Podiatric Medical Association Volume 91 Number 5 245-250 2001}
Reveals only that

dorsiflexion of the hallux caused the medial longitudinal arch to rise, the rearfoot to supinate, the leg to externally rotate, and the plantar aponeurosis to become more tense.

. But surely by heel lift the orthotic, which ends before the MPJ is no longer relevant anyway?

Kind regards
Robert
Confused of Maidstone

[Admin]

robertisaacs said:

Much cut........

Reveals only that

dorsiflexion of the hallux caused the medial longitudinal arch to rise, the rearfoot to supinate, the leg to externally rotate, and the plantar aponeurosis to become more tense.

. But surely by heel lift the orthotic, which ends before the MPJ is no longer relevant anyway?

Hi Robert,
Good observation. IMO a RF-posted orthosis needs much wedging to achieve the same as a titchy (2-degree) FF post (in terms of clinical effects).
Cornwall and McPoil did a study back in 1992 which compared rhe effects of RF posts vs FF posts and no posts on FF forces (I think I'm right here - it's a while since I read this Paper).
Cornwall M W, McPoil T G. Effect of Rearfoot Posts in Reducing Forefoot Forces. JAPMA Vol 82. 7. (1992)

I don't necessarily suggest that the RF post is redundant, simply that I and others have found it unnecessary in many/most cases.

Cheers,

[robertisaacs]

David.

Just so we are using the same terminology what do you mean when you say FF post? I ask because to some this is a wedge under the leading edge of the 2/3rds orthotic (the shaft of the mets) and some mean a ff varus extention.

I ask because if its a 2/3rds orthotic then even a ff wedge will do little once the heel raises.

I'll go check the ref. Cheers M8

Robert

[Admin]

robertisaacs said:

Just so we are using the same terminology what do you mean when you say FF post? I ask because to some this is a wedge under the leading edge of the 2/3rds orthotic (the shaft of the mets) and some mean a ff varus extention.

I ask because if its a 2/3rds orthotic then even a ff wedge will do little once the heel raises.

Hi Robert,
FF post is either medial or lateral - on a 2/3rds orthosis.
Agreed, it does little once the heel is off the ground, but it seems to do quite a lot at mid-stance and early heel-raise. My interpretation is that it positions the foot for economical (mechanically advantageous) toe-off.

It also helps, in the case of Pes Cavus (or uncomp equinus - whatever we want to call it) to stabilise the foot and remove some of the risk of inversion sprain. In my experience heel wedging does not do this as effectively as forefoot wedging.

Cheers,