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Hello, I´m a Spain student. I would like know about casting techniques, I know two forms to abotain the cast of the feet.

a) Suspension technique (I think that it types so), who is about take the fourth and fifth metatarsal head and take to the neutral position.

b) Pression technique: it´s about press in the external side to block the midtarsal articulacion to take the neutral position.

how many techniques you know in weightbearing???

Thanks

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HI Ivan, welcome to the wonderful world of podiatry :)

You will find various practitioners use various techniques to cast, and everyone has there opinion as what works best.

At uni i was taught the suspension technique with the patient supine, an apply pressure to the 4th and 5th met heads, thereby locking the MTJ and moving the entire foot to the position you felt was neutral (with the other hand on the head of the talus). This allowed you to see if tib ant fired which would dorsiflex the first ray, and be detrimental in orthoses manufacture. This is the technique i used throughout uni.

However, when i began work arfter uni, I found i felt i had a better visualisation of the foot with the person prone and looking down at the posterior aspect of the foot. This is the best way to identify Forefoot to rearfoot alignment, and therefore i feel the best wat to have maximal control over the foot as you cast. If tib ant fires, I believe you can feel it, and see the first ray elevate, so this is not a worry to me. I feel i get a far better cast this way.

In regards to how many methods I know in weightbearing, I choose not to use weightbearing as i feel you will not get the good results you can get when casting non-weightbearing. If you are casting a patient, they will have have biomechanical abnormality, hence why you are seeing them (duh!??!!). IF you cast them while standing, you are capturing them with abnormal posture, whereas non-weightbearing you can manipulte the foot (must be careful with that word ) to a postion you see as biomechanically corrected.

Holding the foot in neutral while weightbearing i find difficult, as you will find the first ray will nearly always dorsiflex, which will again be ineffective when made into an orthotic device.

This is obviously my opinion Ivan, and im sure with casting a few times you will find what works for you.

Good luck!!

__________________
My karma ran over my dogma .....

Welcome Ivan,

I am a clinician podiatrist also from Spain. Regarding your questions and Dawesy comments, I would like to add the following:

1. There is no concluding data supporting that non-weightbearing or other casting techniques have better outcomes on relieving foot conditions.

On the study:

Redmond, PS Lumb, and K Landorf
Effect of cast and noncast foot orthoses on plantar pressure and force during normal gait J Am Podiatr Med Assoc 2000 90: 441-449.

The Root type casted orthotics have better results because it was compared with a non-casted simple insole with 6 degrees varus rearfoot post! You must consider that any device with certain shape will have greater influence on foot moments (forces and its directions) that a flat insole.

On the study:

Vivienne Chuter, Craig Payne, and Kathryn Miller
Variability of Neutral-Position Casting of the Foot
J Am Podiatr Med Assoc 2003 93: 1-5.

It was found that he range of the forefoot-to-rearfoot relationship across all groups ( Ten inexperienced and ten experienced clinicians ) was from 10.0° everted to 6.5° inverted.

On the study:

Payne C, Chuter V, Oates M, Miller K
Evaluation of a weightbearing neutral position casting device.
Australasian Journal of Podiatric Medicine 35(3)65-71 2001

This study compared neutral position weightbearing casts
of the foot using the Foot Alignment System (FAS) to
traditional non-weightbearing casts. The FAS system has a number of
theoretical advantages over other weightbearing methods of
modelling the foot compared to the traditional nonweightbearing
casting.

On the study:

Laughton C, McClay Davis I, Williams DS.
A comparison of four methods of obtaining a negative impression of the foot.
J Am Podiatr Med Assoc. 2002 May;92(5):261-8.

It was found: 1) foot measures are significantly influenced by the method used to obtain a negative foot impression; 2) the methods differ in reliability; and 3) plaster casting may be preferable to the other three methods when it is important to capture the forefoot-to-rearfoot relationship, as in fabricating a functional orthosis.

2. Foot main function accurs during weightbearing conditions and (far more important) inside a shoe.

3. There is no reliable data on forefoot-to-rearfoot relationship.

Thus, we could conclude that neutral non-weightbearing casting technique is quite inaccurate and it is only useful is you are following the theory of forefoot-to-rearfoot relationship. The main goals for orthotic therapy are symptoms relieving and function improvement, and you can achieve these goals from different approaches including non-casted devices such as CAD-CAM orthotic manufacturing.

Thanks for your answer Javier. I think like you before read your asnwer but I would like know you think about non-weightbearing or weightbearing casting techniques.

My practice seems me that the neutral position isn´t forefoot and rearfoot in the same relationship, but the non-weightbearing technique has other inconvenience: some flex deformities can dissapear using this technique, like 1st MTT in plantarflexion (flexible), beacuse it´s very difficult to control the plantar foot.



PD (Javier): I study Also in Barcelona University.

Hello Ivan
Both non weight bearing and weight bearing casting are right and wrong. I think it depends on the person and the level of interference in a persons gait that you wish to achieve. I have always found that children and young adults can cope better with more posting and rectification. However I still believe that by the time extensive cast rectification has taken place we are getting away from the purity of the intervention and end up with too complicated devices that achieve little in the footwear that we currently use. Never mind the compensation taking place in the archetecture of the bones of the foot nobody ever seems to account properley for the distributions of the underlying soft tissues. Medial and lateral expansions appear to be more guess work than anything along with the other skives, platforms and crevices. I have seen podiatrists asking for 1 degree posts? Most posting sinks into the soft inner shoes and most people slide against the rear foot and forefoot. Capturing the foot in a semi weight bearing fashion is just as relevant and probably just as valid, but does not get as much discussion because generally the specialists try and keep as much technical information in as possible to confuse not only the public but other podiatrists. As my old teacher in the RAMC said
'its the three B's son....Bull****, Baffles, Brains!'
I have seen many great papers proving one small piece of information whilst ignoring ten others, at Salford University 2 years ago one speaker reminded us that 99% of papers published amount to very little and that for everyone there is usually a counter arguement... butter is bad for you... butter is good for you .... prone is best....supine is best..
Remeber though that if you just treat your patients nicely 50% feel better straight away!
If you want a method of producing a semi weight bearing casts I can let you have details. Just email me at philipaclayton@hotmail.com
best of luck

You right Philip. When you modify a cast using plaster expansions and intrinsic posts the result have few resemblances with the original cast. Furthermore, if you send this cast to a lab, all rectifications will be made by a technician with little knowledge from foot function using lab protocols and standard processes.

Ivan, my opinion about casting processes is that it does not matter what technique you use if you are aware about how body works (not just feet). The goals will be achieved through the orthotic itself: 1. Materials; 2. Shape; 3. Posts.

Nice to hear a future podiatrist with critical sense. Keep your knowledge hungry.

Javier

Hi Javier
I agree that we must take a holistic view to treating the patient for their complaint and we must take advantage of all aspects of treatment. This must include exercise, life changes and especially choice and fit of their shoes.


Dawesy I too agree that prone is best to observe the forefoot to rearfoot relationship but not when casting. Casting prone encourages the practioner to place the foot into a position that they see i.e. varus, whereas casting supine in STJ neutral stops the practioner inteferring in the process and allows you to also see easily whether the Tibialis anterior is firing. However I am not sure that weight bearing casts the foot in 'biomechanical abnormality' as discussed on these forums just what is normal? I do not think you capture them with 'abnormal posture' it is very much their 'normal' posture in the truest sense of the word, and captures their forefoot to rearfoot relationship under the normal forces acting on the foot. I am also unsure about being 'biomechanically corrected' which just sounds painfull!
As with many debates on these forums how many people can actually detect and measure these so called abnormalities because it seems that it is very much down to the practioner as to what they can see or measure and then how they interpret what they see and then what they prescribe and who makes them etc. In pure Rootian theory then you are ofcourse correct but I contend that extremely good results for many patients are found by casting weightbearing as I am sure they are also made non weight bearing and also 'off the shelf'. It is just knowing when to use each therapy.

For instance if you found a patient with a 6 degree STJ varus and 3 degree tibail varum what would we produce? A rigid FFO with 6 or 9 deg post?
What if the patient were 14 years of age?
What if they were 34 years of age?
What if they were 64 years of age?
What if they were overweight?
What if they would not change their 3 inch heels?
What if they would not pay more than £75?
Have you a gait Lab set up?
How do you cast?
What materials do you use?
What type of shoes are they going in?
What activity are they being used for?
Do they need exercises?
Will they exercise?

Its all 'Horses for courses' and we can just try our best to consider every aspect and change our treatments to cover each type of patient. The text books tend to be simplistic in terms of how to fill in a prescription form and leave the Lab to make the choices. It is still very much an 'ART' and until there is an agreed exanination proceedure that everyone can use and simplified prescribing with labs that produce work to a similar standard then we are on our own.