Working as a self-employed orthopaedic practitioner, it is rare that I get the opportunity to thoroughly test a new product or trial new techniques. I have been afforded just such an opportunity through the kind offices of the unit manager where I am contracted.
I have recently been working with a splinting product known as Woodcast. During the last few weeks I have been using the product and it has proven to be a novel and valuable solution for many of my potentially difficult casting situations. These pages will document some of that recent usage with illustrations and commentary.
Disclaimer: I am not an employee of the company that manufactures and markets Woodcast. I do not sell the product nor do I receive any commission payments. I was not asked to write these pages; which I have written to reflect my own observations, thoughts and opinions. These pages are offered as information to the wider orthopaedic cast technician community and to inform my orthopaedic practitioner colleagues about Woodcast.
The splinting material is made from wood and biodegradable plastic. The Woodcast website describes the product thus: Woodcast is a completely non-toxic and perfectly mouldable & remouldable cast material suitable for all casting work. It is manufactured from clean wood and biodegradable plastic and can be moulded without water or rubber gloves.
The product is supplied with two heating devices that render it pliable and mouldable. I found that the hotplate, which can heat and keep the product warm all day, was useful for planned attendances. The needs of the patients were assessed prior to their visit and the appropriate materials selected and heated for their timed appointment attendance. This flat plate could be left working for long periods of time and its capacity was for four short lengths of material or two long lengths.
The second heating device is an express heater which can heat the material for remoulding once it has been formed into a splint. It has three different time settings. Long lengths of material can be heated quickly because they are supplied pre-folded and are inserted in the device over a jig that keeps the folded sections apart from each other.
The materials to be heated could be offcuts and any combination of size and shaped pieces. The long or short 2mm sheets required 10 minutes to reach working temperature and the 4mm sheets required about 20 minutes before reaching working temperature on the hot plate. The express heater takes a matter a few minutes.The illustration shows some Woodcast material laid on the hotplate before use.
The image below shows the simple controls of the hotplate. They consist of indicator lamps for power on and heating on and a simple pair of buttons, marked with a plus or a minus symbol, that may be pushed to raise or lower the temperature of the hotplate. This picture shows the temperature is set to the recommended level
The characteristics of any splint may affect the perception of patient; with regard to the selected treatment acceptability. The subsequent patient compliance with any particular treatment requirements may be adversely influenced by any negative notions which they have about the proposed course of treatment. The treatment which is commonly prescribed for a Charcot neuroarthropathy would be a typical example.
This condition involves long periods of time with frequent and regular cast changes. The cast is often constructed using a plaster of Paris total contact cast which is then overlaid with some lightweight casting material. Some clinicians prescribe the addition of a Bohler iron. The casting process is often carried out every week and the resulting casts may be quite bulky and heavy.
One patient requiring foot offloading treatment was treated with a Woodcast splint. The decision to use this material was based upon the immediate domestic needs of the patient. Being self-employed, the patient stopping work would have meant no income being available to the family for an indeterminate period of time.
It was clear from the state of the casts which were replaced that patient compliance was a major issue. A single 4mm thick 12.5 x 80cm piece of Woodcast was used as a posterior 'L' shaped splint and it was laid directly onto a bouclette type stockinette. Lohmann-Rauscher TG Soft
The foot plate was stretched widthways to accommodate the whole plantar surface. The stockinette had a piece of 2mm orthopaedic felt applied along the anterior tibial crest and the dorsum of the foot. The cast was completed using BSN Delta Cast Soft.
The 4mm thick Woodcast splint was highly malleable and it followed and adapted to the shape of all of the contours of the patient's foot without difficulty. The splint was secured by applying a single roll of 10cm wide Delta Cast Soft. Using cool dipping water provided the unexpected benefit of rapidly cooling the Woodcast splint and the material hardened to its full set strength immediately.
The patient was able to be weight-bearing immediately. Each week the patient had skin checks and dressings to several areas of skin loss on the leg. The foot shape resolved relatively quickly and temperature changes (measured at ten distinct points on each foot for comparison purposes) indicated that the disease process was becoming quiescent when compared with previous measurements.
What was clear was that the splint made from 4mm thick Woodcast material was very strong (the patient weighed more than 116 kilograms) and conformed accurately to the contours of all of the anatomical features being splinted. The soft casting tape securing the splint could be cut through very easily with scissors.
The splint could be reapplied as it was or rapidly reheated and remoulded in the express oven provided by the manufacturer of Woodcast products. Covering the stockinette and splint with pre-tape made the removal of the soft cast securing layer a ten second job after it was cut. The splint did not suffer any damage when the patient had used it for weight-bearing and the product is very strong.
The image below shows the preparation of the limb before applying the Woodcast splint. In this case (the first cast application with Woodcast) it was thought that the splint material needed to be wide enough to permit a degree of wrap around the limb. The orthopaedic felt was applied as if it were for a standard below knee cast.
The technique for a splint applied every week has been further developed. Now a single width of 12.5cm x 4mm splint is applied. There are no complicated bends or cuts to be made in the splint material. The single roll of soft casting material is more than up to the job of holding the splint in place. The comfort of the patient is assured by fitting a secure cast shoe of the post operative pattern.
Author's note: The requirement to rest a neuropathic foot with diabetic ulcer and skin complications is well documented and understood but in this particular case the patient's domestic needs could not be ignored. A prolonged absence from work would have presaged financial ruin for the patient and their immediate family members.
Another application of Woodcast splinting material was as the under-sole of a removable cast shoe which was used for a patient with dressings to diabetic foot ulcers. The dressings were being treated every three days and a cast shoe that would spread the load of the foot while being removable was the clinical requirement.
Woodcast is a material which is highly conformable and easy to apply. It provides a very solid surface under a cast and was easily incorporated into the design of removable shoe that was constructed with a soft casting tape.
This cast application would have been far more difficult to achieve with plaster of Paris as the total contact layer. Plaster of Paris is subject to fatigue with protracted use and it would have taken three days before the cast was able to take the weight of the patient. As with many diabetic patients, the person being treated was overweight and had many diabetic foot ulcers.
The foot shape suggested a previous collapse of the bone structure and all of the attendant risks of casting diabetics were present. Woodcast splint material is capable of being remoulded easily and within minutes, for patients who have a change in the shape of the body part being cast.
The open splint is a more reassuring option than totally enclosing a diabetic foot. These patients have feet which are frequently damaged and provide restricted sensory information so that they cannot feel when things are going wrong under a complete cast.
The patient was comfortable on leaving the plaster room and could walk immediately. The diabetic foot clinic could continue with their regime of patient attendance every three days to treat foot ulcers. The casting technique was learned quickly and without difficulty.
It was a simple matter to adapt the technique to each patient requiring a cast which had mandated any specific element of serial casting and Woodcast splintage was able to help with delivering the solution. This particular cast shoe assisted the patient, by being easy to manage, lightweight and offloading the ulcerated areas while still being strong enough to walk on immediately.
The Woodcast soled shoe facilitated the work of the podiatrists treating the foot ulcers and did not require any extended cast removal and recasting times. It permitted the treating clinician to specify a treatment that normally would have required a lot of resources and clinical overhead.
It meant that more patients could be seen in a shorter time than would normally be the case and the patient throughput was greater. The treatment was of benefit to the hospital trust because each clinical service involved was seeing and treating more patients... far more effectively.
The Woodcast product is amenable to joining pieces together with a narrow flexible strip of material and it can stick to itself very easily. It provides joins which have the identical profile to the splinting material without a join. Where pieces of splint are pinched together and then the excess material trimmed with scissors, the join on the inside of the material is, for all intents and purposes, seamless. The images below demonstrate that capability.
Charcot Neuropathic Foot - Commentary
The course of treatment for a Charcot neuroarthropathy in patients with diabetes can be protracted. Casting with total contact casts for diabetic foot ulcers is currently the gold standard in treatment. Pulling together all of the strands of possible treatment options is no easy task.
The inaugural issue of CARE is an e-publication produced by Glasgow Caledonian University. CARE is a Clinical and Academic Research E-journal for new authors in the interdisciplinary health community. It published a paper (Hunt, 2007) where much of the research concerning total contact casting was reviewed.
Once the selected patient was made aware of the new splinting and offloading method to be used, it provided the means to manage the splint. The simplicity of offloading the foot by spreading the load evenly was aided by the fact that there was no plantar ulceration for this particular patient.
The collapsing bone structure (which is a feature of this particular form of neuroarthropathy) had stabilised and the foot shape had become more regular. The need of this patient to continue to weight-bear, and thereby enable working in the family business, had outweighed all other considerations. The patient had not wanted to have improved foot health at the expense of becoming bankrupt and losing the only means of income generation for supporting his whole family.
The Woodcast splint reduced the time required to treat the patient every week. The splint could be re-used and remoulded where necessary, to ensure a better fit. The component parts to the cast were the bouclette stockinette, the existing Woodcast splint, a layer of casting pre-tape wrap and a roll of soft cast material. The total time taken to remove and reapply the total contact cast/splint was around 10 minutes.
The ability of the Woodcast splinting material to adopt the shape to which it was being moulded and accurately mimic every contour, opens the door to an exciting development in the management of some Charcot Neuroarthropathic conditions. The technique employed will not suit every patient. The splinting can take the place of plaster of Paris and reduce the bulk and the weight of the standard total contact cast.
Where this specific Woodcast technique is employed, it will substantially reduce the time required to manage TCC casting; in addition to reducing the costs of providing a total contact cast treatment option. It is likely that this abbreviated technique of supporting a Charcot Foot will also reduce the risk of iatrogenic complications because one does not have to enclose an insensate foot in a complete cast.
Distal Radius Fractures
One clinician in my current workplace has approved the use of Woodcast splints for minimally displaced distal radius fractures. The radiographs below illustrate the type of cases where Woodcast splints are being applied.
The Woodcast splints displayed some excellent characteristics when used for minimally displaced distal radius fractures. The method was to form a splint, from a previously cut and shaped Woodcast material template, around the patient's limb over a layer of bouclette stockinette. The shaping of the splint was achieved by moulding the warm splinting material with a crepe bandage that was soaked with cold water.
The bandage was held in situ for around 20 seconds to permit the Woodcast splint to achieve its full set strength. A dry bandage could be used with an increase in setting time to a few minutes. A cold air blower such as a hair dryer could possibly be used too but this has not yet been tested.
The fully hardened splint is then edged with a sticky-backed felt such as BSN Delta Terry Net adhesive fleece liner and the splint is then applied and bandaged to the patient's forearm with cohesive bandage. The splint is fast to produce, lightweight and open in the same way that any below elbow slab would be.
Once the period of immobilisation is complete, the splint can have velcro strapping added thereby changing it into a supporting splint for the recovering injury. This would remove the need for issuing a futuro type wrist splint.
The Woodcast splint is made to measure for the patient and easily converted to a removable splint. The material provides adequate support while remaining slightly flexible. Patient compliance is high and patient acceptability (thus far) appears to be better than with a circumferential cast.
Distal Radius Fractures - Commentary
The splint material, when it is set, displays a high level of dimensional stability. Any injuries where continuing oedema is a problem would benefit from a splint that is open on one side and has sufficient flexibility to expand if necessary.
The anatomical moulding properties and pliability are excellent and they facilitate and ensure patient comfort. The product may get wet accidentally as casts may do on occasion but skin maceration will not happen. The stockinette can be changed and the same splint can be reapplied.
The Woodcast oven may be used to reheat and remould the splint. This method of work ensures that the same splint can be reapplied throughout the duration of treatment. The limb may change in shape substantially, after the initial injury or corrective surgery, and the ability of the same piece of splinting material to be used repeatedly to meet changing circumstances is a novel advantage.
This type of splinting is substantial enough to hold many fracture patterns while they heal. All stable distal radius fractures should be amenable to splinting with this material. The proviso is that the fracture is stable and has not been the subject of a reduction.
Techniques for casting any correctly and well-reduced distal radius fractures can be developed. Unstable fracture patterns would not benefit from this type of splinting because of the risk of fragment movement. Woodcast splinting material has excellent working properties and is radiolucent to a high degree. This means that X-ray images, taken during the wearing of a splint, will demonstrate every salient feature.
Woodcast splinting has been used to support surgical procedures. The illustration below shows a splint that was applied after a bimalleolar fracture was repaired. The foot position was not ideal but the patient was finding it rather difficult to dorsiflex the ankle joint. This was because the surgery had taken place three days previously and the plaster room attendance was for a wound check.
Supporting Surgery - Commentary
The patient would go on to have the sutures removed at around 14 days post operatively and the splint remoulded in the oven supplied by Woodcast. This device heats the splinting material within a couple of minutes and it can be remoulded to fit the patient's changing anatomy.
The patient will be splinted non-weight bearing for six weeks. With the imprecation not to place any weight through the leg, the patient will be able to remove the splint and wash the skin. A spare stockinette and cohesive bandage allows the patient to wash the stockinette and keep their injured limb comfortable and clean during the six weeks of immobilisation.
I have also used Woodcast splints to support extended treatment by way of serial casts for children who are walking on their toes and need constant soft tissue stretches over a period of weeks. These splints are applied as has been described above for Charcot Neuroarthropathy.
They are constructed from 2mm thick Woodcast splinting material and they can be reshaped for every attendance. When the treatment period of casting has ended, the splints can be very easily adapted with a couple of Velcro straps so that they can serve as temporary ankle foot orthoses (sometimes known as night splints) until Piedro boots have been delivered.
Another area of usage has been the treatment of base of 5th metacarpal fractures. These have traditionally been cast in volar slabs or ulnar gutter splints, with the phalanges held in extension and the metacarpophalangeal joints held in full flexion. The wrist is held in extension of around 30 degrees.
Recently, I have had a couple of patients who could not wear such a protective slab of plaster. The decision was made by the clinician to treat the patients using supportive splinting that could be removed if chosen.
The occupations in rural England often include animal husbandry or arable farming. One of my patients was a pig farmer and very frequently had dirty wet hands as part of the job. The other patient was a gardener and frequently found that gardening detritus had a negative impact on any sort of plaster cast.
Both patients were self-employed and it is incumbent upon the treating clinician to consider the impact of any treatment prescribed. Accordingly, both patients received the heavily modified ulnar gutter splint illustrated below.
Fractured base of 5th Metacarpal - Commentary
We may think of treatments delivered as being 'wrong' but our work does not take place in a vacuum. It is a legitimate part of our role to adapt our methods to suit personal circumstances, where the intended or standard treatment would prove to be inimical to the interests of the patient.
The demonstrated splint may appear to some practitioners as incorrect. The adaptation of new materials and methods to serve the patient better is not a concept with which I have any issue. Both patients were delighted to receive such individual care and attention and both became more compliant as a result of the offered splint, not less compliant.
They received some supportive treatment rather than no treatment at all, which is what the best current practice of a plaster ulnar gutter or volar slab in the safe position would have offered to them.
Woodcast usage - Commentary
This splinting material is a delight to use. It will assist the orthopaedic practitioner to find easy solutions to complex splinting needs. In the short time during which I have used the material, it has proven versatile, clean and remarkably easy to apply. The patients all seem happy with its weight and ease of wearing. It has not produced any adverse reactions on the skin and it has caused me to think very deeply about the manner in which we apply casts which are circumferential.
I suspect that some of what we currently do (by way of technical practice) makes less sense than it should and the mechanical advantage to be derived from a circumferential splint in every circumstance may well be overstated. The comfort of the patient and their ability to carry on with their lives normally, is a factor that contributes to their progression from incapacitated to fully functioning.
The work of the Virtual Fracture Clinic is instructive and where it is combined with splinting that is minimal but effective, we could witness a complete sea-change in current fracture clinic management.
Understanding of Woodcast splinting material includes the fact that it does not contain isocyanates. These substances have been implicated in the development of workplace asthma within the construction industry. Many casting tapes do include isocyanates and they would not be effective if they did not.
Whether isocyanate free casting tapes are being manufactured or not, it is possible that the issue will grab the attention of legislatures across Europe and significant practice changes for cast technicians may already be in the post.
Treatment costs are important and Woodcast may appear unsuited to every cast-room need, despite its possible suitability and the probable encouragement of initiating new techniques which underpin minimal splintage. Where casting and splinting is likely to be long term such as with serial casting or for the treatment of Charcot's neuroarthropathy, the cost/benefit analysis is very promising. The same piece of Woodcast splint material can be used for many treatments for the same patient and repurposed whenever the need arises.
The case for using Woodcast splints for minimally displaced wrist fractures looks to be untenable on first examination. Closer examination reveals that the cost of applying a below elbow cast with a premium product such as 3M Poly Premium is around £4.44 including VAT; after the undercast stockinette, wool and felt padding are factored in. The cost of BE splinting with Woodcast is about £9.53 including VAT and TG stockinette plus a roll of soft casting tape or cohesive bandage or crepe bandage.
It is tempting to say 'no contest' and continue with our present system of work, which must be common across many NHS trusts throughout the UK. The normal pattern of work is that a temporary posterior slab made from plaster of Paris (POP) is applied in the emergency department.
The fracture clinic work usually involves removing the POP slab and then applying a circumferential cast in some form of lightweight casting tape. Finally, the patient's injured limb is considered healed and they may receive a wrist splint or a fixed walking boot to support their injury during the tertiary stages of healing. Additional support may be supplied by physiotherapist or hand therapists.
One of the interesting use cases for Woodcast is that it can be heated and reapplied to the same patient multiple times (e.g. once the limb oedema has resolved) There is no compelling reason why Woodcast could not be applied at the initial emergency department attendance, as if it were a posterior slab.
At the subsequent fracture clinic appointment, the Woodcast splint could be refashioned to ensure a close fit once the oedema of the injured limb had resolved. After the patient's injured limb was functionally healed, the Woodcast splint could be refashioned to simply support the rehabilitation phase of fracture recovery.
The simplicity and acceptability of ulnar gutter splints illustrated in these pages is an easy usage to support. The cost of producing them is the cost of the material (four ulnar gutter splints can be fashioned from a single sheet) and 5 minutes of time.
The fact that they can be removed easily and last for the duration of the treatment makes them a very attractive proposition, especially where the treatment keeps the patient away from the hand therapist; by dint of patients being able to appropriately exercise their hands and fingers at regular intervals throughout the treatment period.
There would be a small cost in moving to a bouclette stockinette such as TG Soft although Woodcast bonds very easily to standard undercast stockinette. There would be no need to apply undercast wool and every cast-room holds and uses a stock of non-compressible undercast felt padding for protecting bony prominences.
All of the splints could be removed with a pair of scissors, where appropriate padding is applied and soft casting tapes are used. Splints held on with cohesive bandage or velcro strapping are easy to make and apply.
Post surgery cast application would benefit from the use of Woodcast techniques. A bimalleolar ankle fracture could be repaired surgically and then protected with a Woodcast splint, which would probably need to be based upon a stirrup design.
As the oedema resolves, the splint could be repurposed and reapplied. The patients would be at less risk of compartment syndrome post surgery or some traumatic emergency because of Woodcast splinting techniques which leave an open aspect.
It has been possible to test Woodcast splintage in a variety of common use cases. Poor application technique is a risk but that risk exists with every form of cast and splint application. The temperature at which the material becomes fully malleable is unlikely to cause any thermal injury.
If the Woodcast splinting material was hot enough to cause a thermal injury to the patient, then it would be too hot for the operator to handle. It does not require gloves to handle so that too is a cost saving. The supplied express oven and the hotplate are electrical appliances and they should be PAT tested to ensure that they are suitable to be used for their intended purpose.
I have found the use of Woodcast (in a large variety of common orthopaedic clinical situations) to be safe and effective. Poor operator skill is a possibility and this can be addressed through appropriate training. Prescribing inappropriately may take place where a clinician has misunderstood the properties of Woodcast and tries to use it in situations for which it was not intended or tested. I have no hesitation in recommending Woodcast for the treatment of stable fracture patterns.
Unstable fracture patterns are challenging to cast in any event. Care needs to be taken to ensure that the splinting material is not used to attempt to hold fracture patterns that would potentially shift inside an expertly applied circumferential cast. The costs savings for treating cases with serial casting needs, from idiopathic toe walking to Charcot Neuroarthropathy, are considerable. The possibility of applying EDF jackets for idiopathic scoliosis is an exciting one.
Patient compliance is excellent and the time savings for the cast technician are immense. Currently, I would not recommend the use of Woodcast splintage in the case of serial casting for congenital talipes equino-varus (CTEV). One would like to see a Ponseti splint modified for the purpose of using Woodcast. The benefits to parents and the children in keeping splints free from urine and faeces must be worth pursuing.
The difficulty of manipulating and positioning the foot of a two week old patient would probably militate against achieving an accurate foot position. I am willing to be proved wrong but without specifically developing the method to be used with Woodcast, I suspect that it would be an exercise in frustration; from my personal experience of applying POP serial casts for CTEV. The ability of a Woodcast splint to be held in place with crepe bandage, cohesive bandage, velcro and soft casting tapes, makes it an extremely versatile product.
Isocyanates in lightweight casting tapes
Isocyanates are considered to pose risks to workers exposed to them. The information about isocyanates is gathered from the manufacturer provided material data safety sheets and the wealth of research work which mentions that occupational asthma is a known consequence of sensitivity to the isocyanates, methyl diethyl diisocyanate (MDI) and toluene diisocyanate (TDI).
Where a known risk to respiratory health following isocyanate contact has been identified (it has) then that risk is empirical in nature. The risk to cast technicians appears to be unknown and as yet unquantified. The lightweight casting tapes appear to favour the inclusion of MDI, which is considered to be less toxic that TDI.
Donelly and Buick et al, (2003) have detailed a case of respiratory sensitization to MDI in a nurse who applied synthetic casts during a four year time span. They found references detailing similar effects in two other workers. However small, the risk of respiratory sensitization has been identified in workers who use products containing MDI.
Woodcast represents a new and exciting direction for cast technicians. The product is easily substituted for many of the use cases with which cast technicians come into contact. There would be an instant reduction in the risks from MDI containing casting tapes.
Some initial concerns about the costs were evident but the health and safety of workers and patients is more important. It can be seen that a change in methods of work would make the Woodcast splinting product more attractive from a cost point of view.
There are several areas of use where Woodcast can impinge on other areas of specialist use. Hand therapists and orthotists can also make use of this versatile splinting material. I envisage that local policies would be developed to permit cast room personnel to apply Woodcast splints which can later be readjusted by specialist staff.
This is no different to emergency rooms actually becoming the places where the beginning of the orthopaedic treatment is initiated, rather than just being a provider of emergency orthopaedic splinting with little thought as to the consequences of their work.
Isocyanates - Health and Safety Executive
Isocyanates - United States Department of Labor
Am J Orthop. 2012;41(3):132-139
Bello and Herrick et al (2007)
Skin Exposure To Isocyantes: Reasons For Concern
Environmental Health Perspectives - Vol. 115 #3 March 2007 pp328 - 335
Baur and Barbinova
Occupational airborne exposure, specific sensitization and the atopic status: evidence of a complex interrelationship
Journal of Occupational Medicine and Toxicology 2013, 8:2
Donnelly and Buick et al (2004)
Occupational asthma after exposure to plaster casts containing methylene diphenyl diisocyanate
Occupational Medicine 2003;53:432–434
Gogoi and Niyogi et al (2013)
Study of Effect of NCO/OH Molar Ratio and Molecular Weight of Polyol on the Physico-Mechanical Properties of Polyurethane Plaster Cast
World Applied Sciences Journal 21 (2): 276-283, 2013
N.B.the article above was included because it provides a clear introduction to the role of isocyanates in lightweight casting tapes