Three-dimensional analysis of the gap space under forearm casts

PurposeSecondary displacement represents a frequent complication of conservative treatment of fractures, particularly of the distal radius. The gap space between skin and cast may lead to a certain degree movements and this increased mobility might favor redisplacement. The aim of this study was to develop a new 3D method, to measure the gap space in all 3 geometrical planes, and to validate this new technique in a clinical setting of distal radius fractures.MethodsThis study applies 3D imaging to measure the space between plaster and skin as a potential factor of secondary displacement and therefore the failure of conservative treatment. We developed and validated a new methodology to analyze and compare different forearm casts made of plaster of Paris and fiberglass. An unpaired t-test was performed to document differences between the investigated parameters between plaster of Paris and fiberglass casts. The significance level was set at p < 0.05.ResultsIn a series of 15 cases, we found the width of the gap space to average 4 mm, being slightly inferior on the radial side. Comparing the two different casting materials, plaster of Paris and fiberglass, we found a significantly larger variance of space under casts made of the first material (p=0.39). A roughness analysis showed also a markedly significantly higher irregularity of the undersurface of plaster of Paris as compared with fiberglass.ConclusionThis study allows for a better understanding of the nature of the “gap space” between cast and skin and will contribute to develop and improve new immobilization techniques and materials.     

Mechanical assessment of polyurethane impregnated fibreglass bandages for splinting

The introduction of polyurethane (PU) resin impregnated fibreglass bandages is likely to have a significant effect on modern orthopaedic practice. The manufacturers of these products claim many improved properties compared to plaster of Paris bandages, such as , high strength to weight ratio, rapid setting time and high radiolucency. This paper reports on a series of mechanical tests designed to assess the strength, flexibility, working time and wear properties of the current range of fibreglass bandages and to compare them with plaster of Paris bandages. The results have clearly demonstrated that the fibreglass bandages are mechanically superior and offer numerous advantages over plaster of Paris for use as the definitive casting material for both weight-bearing and non-weight-bearing casts.     

Treatment of clubfoot with the Ponseti method: a comparison of casting materials

BACKGROUND: Popular initial treatment for congenital clubfoot includes the use of serial manipulations and casting as described by Ponseti et al. Plaster of Paris and semirigid fiberglass are 2 materials commonly used for casting. To our knowledge, no study to date has compared the clinical results of these 2 materials. The objective of this randomized prospective study was to compare the effectiveness of these materials in the initial management of clubfoot. METHODS: All clubfeet presenting to the 2 senior authors' outpatient clinics over a 15-month period were offered enrollment. Patients were randomly assigned for treatment with either plaster or semirigid fiberglass casts. The severity of the clubfoot deformity was documented using the scoring system devised by Diméglio et al. Serial casts were applied according to the technique described by Ponseti et al. At the completion of nonsurgical treatment, the final clubfoot severity was documented. RESULTS: A total of 42 clubfeet in 34 patients were enrolled in the study. After exclusion of 3 patients, 13 patients (16 feet) received fiberglass, and 18 patients (23 feet) received plaster casts. The mean baseline severity scores of the 2 groups were not significantly different. The mean final severity score was significantly higher in the feet treated with fiberglass than those treated with plaster (6.4 vs 4.1; P = 0.037). There was a trend toward higher scores for cast tolerance, durability, and parent satisfaction in the fiberglass group, but this did not reach significance. CONCLUSIONS: This study supports the use of plaster casting with the Ponseti technique. The use of plaster casts resulted in a statistically lower Diméglio-Bensahel score at the completion of serial casting. There was a trend toward higher patient satisfaction in the fiberglass-treated group. Whether this difference has an effect on long-term outcomes and recurrence remains to be studied. LEVEL OF EVIDENCE: Level II. Nonblinded randomized controlled prospective study.     

Hexcelite versus plaster of Paris: a controlled trial of the below-knee walking cast

Hexcelite and plaster of Paris below-knee walking casts were compared in a controlled clinical trial, involving 82 patients. Fewer bandage complications, problems and better comfort was found with Hexcelite compared to plaster of Paris (P less than 0.05). If all costs relating to materials, transportation, complications and extra visits due to these, were taken into account, plaster of Paris was found more expensive than Hexcelite. Based on the above an increased use of Hexcelite is recommended.     

Postoperative blood loss into plaster casts after clubfoot surgery: an experimental model

With major surgery in mind, a simple experimental model was used to study the potential blood loss into plaster of Paris casts. Three lower limb models were used to represent a 3-year-old, a 1-year-old, and a 6-month-old. Two thicknesses of plaster were compared in terms of blood volume required to produce staining on the surface of the cast. Whole blood from the laboratory was infused onto the plaster models at various rates. While allowing for the limitations of the model, the blood volume required before staining through the plaster when three plaster rolls were used was an average of 160 mL in the 6-month-old model and 310 mL in the 3-year-old modal, representing 31.4% and 29.5% of total blood volume, respectively. When only two rolls of plaster of Paris were used, an average of 80 mL in the 6-month-old and 180 mL in the 3-year-old model were lost, representing 15.7% and 17% of total blood volume, respectively. This potential blood loss should be borne in mind during major pediatric foot surgery. The use of drains, releasing the tourniquet before wound closure, and casting with two rather than three rolls of plaster are suggested precautions.     

Exothermic properties of plaster–synthetic composite casts

Purpose

Plaster casts can cause burns. Synthetic casts do not. Composite plaster–synthetic casts have not been thoroughly evaluated. This study analyzed the temperature from plaster casts compared with composite casts in a variety of in vitro conditions that would simulate clinical practice.

Methods

A Pyrex cylinder filled with constant body temperature circulating water simulated a human extremity. Circumferential casts, of either plaster or composite construction (plaster inner layer with outer synthetic layer), were applied to the model. Peak temperatures generated by the exothermic reactions were studied relative to the following variables: dip water temperature (24 °C versus 40 °C), cast thickness (16, 30, and 34 ply), and delayed (5-min) versus immediate application of the synthetic outer layers. Peak temperatures from the all-plaster casts were compared with the composite casts of the same thickness. Finally, the relative cast strength was determined.

Results

Potentially dangerous high temperatures were measured only when 40 °C dip water was used or when thick (30- or 34-ply) casts were made. Cast strength increased with increasing cast thickness. However, the presence of synthetics in the composite casts layers did not increase cast strength in every case.

Conclusion

When applying composite casts, the outer synthetic layers should be applied several minutes after the plaster to minimize temperature rise. Composite casts do not routinely generate peak temperatures higher than plaster casts of similar thickness. Because the skin of children and the elderly is more temperature-sensitive than average adult skin, extra care should be taken to limit the exothermic reaction when casting children and the elderly: clean, room temperature dip water, minimal required cast thickness, avoidance of insulating pillows/blankets while the cast is drying.     

An experimental study of pressure-volume dynamics of casting materials

Casting materials are commonly used in a trauma and post-operative setting in orthopaedic practice. Swelling after trauma or surgery is universal, hence, the importance of understanding the pressure-volume dynamics of various materials commonly used for casting. This study attempts to define the pressure response of casts made from three commonly used materials to increasing volume, using a cylindrical model cast. Plaster of Paris (PoP), rigid fibreglass and semi-rigid non-fibreglass (Softcast) were chosen for comparison. Softcast had the best compliance and rate dependency characteristics, accommodating significantly more volume of fluid compared to plaster of Paris or Rigid fibreglass material. The latter two had similar compliance. All three materials demonstrated stress-relaxation which is of advantage in reducing peak pressures for a given volume change. This study shows that the casting materials behave in a viscoelastic manner, which allows them to accommodate more volume change than would otherwise be possible. The use of semi-rigid material may be safer than other materials as far as response to swelling (volume expansion) is concerned.     

Early mobilization in the treatment of Colles'' fracture: a 3 year prospective study

Ninety consecutive women with unilateral Colles' fractures were randomized into two different treatment groups. The control group was treated for 5 weeks in conventional short-arm, below the elbow plaster of Paris casts. The other group (N = 45) was treated similarly in plaster casts for 3 weeks and then had flexible casting applied for the remaining 2 weeks which allowed for early joint mobilization. Functional recovery was assessed by measuring grip strength and joint mobility at intervals over the 3 years. Radiographic and overall assessments were also made during 3 year course of study. Virtually all patients reported greater comfort after switching to the flexible casting. Mean grip scores and joint mobilities were higher at all time points with early mobilization, reaching levels of statistical significance at 6 months for grip score and at 3 months for joint mobility. By 3 years most differences between treatment groups had resolved. We found no evidence that early mobilization was detrimental to recovery. We conclude that early mobilization is a satisfactory treatment option for Colles' fracture, and may, in fact, hasten functional recovery.     

When should a synthetic casting material be used in preference to plaster-of-Paris? A cost analysis and guidance for casting departments

An accurate cost analysis of the use of one of the new synthetic casting materials (Cellacast) compared with plaster-of-Paris (Gypsona) was undertaken over a 3-month period in the fracture clinic of Cardiff Royal Infirmary. The mean duration of usage before failure for synthetic forearm, scaphoid and below-knee casts was found to be approximately twice that of plaster casts. The use of synthetic casting materials was found to be cost-effective in situations where there was thought to be a high probability that structural failure of the cast would occur. Guidelines for the use of plaster-of-Paris and synthetic casting materials are presented.     

Ponseti casting: a new soft option

We have modified the Ponseti casting technique by using a below-knee Softcast instead of an above-knee plaster of Paris cast. Treatment was initiated as soon as possible after birth and the Pirani score was recorded at each visit. Following the manipulation techniques of Ponseti, a below-knee Softcast was applied directly over a stockinette for a snug fit and particular attention was paid to creating a deep groove above the heel to prevent slippage. If necessary, a percutaneous Achilles tenotomy was performed and casting continued until the child was fitted with Denis Browne abduction boots. Between April 2003 and May 2007 we treated 51 consecutive babies with 80 idiopathic club feet with a mean age at presentation of 4.5 weeks (4 days to 62 weeks). The initial mean Pirani score was 5.5 (3 to 6). It took a mean of 8.5 weeks (4 to 53) of weekly manipulation and casting to reach the stage of percutaneous Achilles tenotomy. A total of 20 feet (25%) did not require a tenotomy and for the 60 that did, the mean Pirani score at time of operation was 2.5 (0.5 to 3). Denis Browne boots were applied at a mean of 10 weeks (4 to 56) after presentation. The mean time from tenotomy to boots was 3.3 weeks (2 to 10). We experienced one case of cast-slippage during a period of non-attendance, which prolonged the casting process. One case of prolonged casting required repeated tenotomy, and three feet required repeated tenotomy and casting after relapsing while in Denis Browne boots. We believe the use of a below-knee Softcast in conjunction with Ponseti manipulation techniques shows promising initial results which are comparable to those using above-knee plaster of Paris casts.     

A novel method of applying a split cast

Split plaster casts have been shown to be better than back slabs at accommodating increasing intracompartmental pressure due to swelling. Splitting a wet plaster cast can be time consuming and difficult both for the patient and the medical staff. We describe a novel method of applying a split plaster of Paris cast, which is safe, quick, convenient and inexpensive.     

A comparison of the mechanical properties of fiberglass cast materials and their clinical relevance

The mechanical properties of five synthetic fiberglass casting materials were evaluated and compared with the properties of plaster of Paris. Two of the tests were designed to bear clinical relevance and the third to determine intrinsic material properties. The effect of water on strength degradation was also evaluated. It was found that the synthetics as a group are far superior to plaster of Paris in all methods of testing and that, among the synthetics, KCast Tack Free, Deltalite "S", and KCast Improved were the stronger materials. Clinically, the most important results are that the synthetics attain their relatively high strength in a much shorter time frame than does plaster of Paris, and retain 70-90% of their strength after being immersed in water and allowed to dry.     

Experimental study on thermal burns caused by plaster bandage

Plaster bandage is frequently used in the field of orthopaedic surgery. Little is known however of thermal burns caused by plaster bandage. Experience has shown that heat producing levels differ depending on application conditions, i.e., water temperature into which plaster of Paris is dipped, thickness of the plaster cast, kind of plaster, etc. We made a series of experiments to find out what factors are related to elevation of the skin temperature in a plaster splint applied to a human forearm. The highest skin temperature of 47.7 degrees C was obtained upon application of a plaster bandage made of 30 layers of plaster with short setting time, dipped in water at 42 degrees C. In this condition the examinee had a first degree burn on the skin surface. Thus, care must be taken in applying a plaster bandage to assure that it does not cause a serious burn to the skin.     

Measurement of the consistency of patellar-tendon-bearing cast rectification

The quality of fit of a trans-tibial patellar-tendon-bearing (PTB) socket may be influenced by consistency in casting, rectification or alignment. This paper quantifies, for the first time, the variations in the rectified casts between two experienced prosthetists and the variation between the rectified casts of each individual prosthetist. Prosthetists A and B observed the hand casting of a typical trans-tibial amputee. Each prosthetist was supplied with 5 previously measured duplicated plaster models. The two prosthetists rectified the supplied plaster models based on their own interpretation of basic rectification guidelines. Both prosthetists operated in isolation. The re-measured rectified plaster model data was compared with the unrectified data. The extent of rectification at each of 1800 locations per plaster model was calculated. In zones of major rectification, the mean difference between prosthetists was quantified as 2mm and the standard deviation (SD) about that mean was +/- 1mm for each prosthetist. The co-ordinates of the apex of the fibular head for the 10 modified casts indicated that the maximum variation was in the axial direction with a SD of 4.3mm for prosthetist A and a SD of 2.8mm for prosthetist B. The lengths of the 5 plaster models rectified by prosthetist A indicated a SD of 0.2mm whereas the lengths of the 5 plaster models rectified by prosthetist B indicated a SD of 2.9mm.     

Diagnosis of periprosthetic infection following total hip arthroplasty – evaluation of the diagnostic values of pre- and intraoperative parameters and the associated strategy to preoperatively select patients with a high probability of joint infection

Background

Most cast materials mature and harden via an exothermic reaction. Although rare, thermal injuries secondary to casting can occur. The purpose of this study was to evaluate factors that contribute to the elevated temperature beneath a cast and, more specifically, evaluate the differences of modern casting materials including fiberglass and prefabricated splints.

Methods

The temperature beneath various types (plaster, fiberglass, and fiberglass splints), brands, and thickness of cast material were measured after they were applied over thermometer which was on the surface of a single diameter and thickness PVC tube. A single layer of cotton stockinette with variable layers and types of cast padding were placed prior to application of the cast. Serial temperature measurements were made as the cast matured and reached peak temperature. Time to peak, duration of peak, and peak temperature were noted. Additional tests included varying the dip water temperature and assessing external insulating factors. Ambient temperature, ambient humidity and dip water freshness were controlled.

Results

Outcomes revealed that material type, cast thickness, and dip water temperature played key roles regarding the temperature beneath the cast. Faster setting plasters achieved peak temperature quicker and at a higher level than slower setting plasters. Thicker fiberglass and plaster casts led to greater peak temperature levels. Likewise increasing dip-water temperature led to elevated temperatures. The thickness and type of cast padding had less of an effect for all materials. With a definition of thermal injury risk of skin injury being greater than 49 degrees Celsius, we found that thick casts of extra fast setting plaster consistently approached dangerous levels (greater than 49 degrees for an extended period). Indeed a cast of extra-fast setting plaster, 20 layers thick, placed on a pillow during maturation maintained temperatures over 50 degrees of Celsius for over 20 minutes.

Conclusion

Clinicians should be cautious when applying thick casts with warm dip water. Fast setting plasters have increased risk of thermal injury while brand does not appear to play a significant role. Prefabricated fiberglass splints appear to be safer than circumferential casts. The greatest risk of thermal injury occurs when thick casts are allowed to mature while resting on pillow.     

Orthopedic immobilization

The classical plaster bandage was devised in the mid 19th century. Until recently, osteoarticular trauma has been treated mostly by plaster cast immobilisation using plaster of Paris. Synthetic materials have been introduced on the market place in the seventies, but they have not superseded the traditional plaster of Paris. The more recent thermoplastic materials are used to make splints and orthoses, particularly at the wrist and hand. The present review of the literature confirms that synthetic materials present better physical and mechanical properties than the traditional plaster of Paris. In addition, they are lighter, they are more resistant to humidity, they are more radiotransparent and they generate less dust when removed. However, they are less malleable and cause higher pressure in case of limb edema. Plaster of Paris therefore remains indicated in the acute posttraumatic or postoperative period. This material is also cheaper, but the pecuniary benefit is limited for several reasons, particularly because plaster of Paris is associated with a higher rate of cast replacement.     

Soak the cast off

Plaster of Paris cast is still the most common form of external splintage used in orthopaedics. It is usually removed by cutting it with an electric oscillating saw. The noise created by this instrument and the sight of the blade can both be frightening, particularly for young children. As Plaster of Paris gets soft with water, soaking it to remove plaster in children is a good option, particularly neonates treated by serial casting for clubfeet. Our experience with this method was very encouraging. There were no failures. Most patients or parents of neonates were satisfied and happy to remove the plaster at home. Average time taken to remove the plaster was 25 minutes.     

Gipstechniken in der Handchirurgie

The correct placement of bandages for immobilization or a functional splint is an essential part of the conservative and postoperative treatment in hand surgery. The classical plaster cast is easy to model and inexpensive. This article gives an overview of the various types of plaster casts for immobilization in hand injuries.     

A New Thermoplastic Casting Material: A Comparison Between Plaster of Paris and Hexelite®

Plaster of Paris and Hexelite®, a new thermoplastic bandage, were compared in the treatment of 183 patients with malleolar fractures, Colles' fractures or distortions of the finger joints. There were no statistically significant differences between the two types of bandages taking into account the strength of the bandage, the amount of skin damage and the patient's opinion of the bandage.

Hexelite® is seven times more expensive than plaster of Paris, and, in addition, is more difficult to handle. Hence its use has been discontinued.     

Primäre definitive Stützverbandbehandlung mit Softcast an der oberen und unteren Extremität

Background

Soft cast (SC) is a semirigid cast material which opened new possibilities for fracture care in adults and children. The primary definitive cast technique (PDCT) with SC is a new casting method that uses a combination of fiberglass and polyurethane resin. Time, personnel, and material costs for producing plaster casts using the conventional technique (primary plaster cast and secondary hard cast, or POPHC) were prospectively compared with PDCT using SC on upper and lower extremities.

Methods

Time, personnel, and material costs for producing plaster casts using the conventional technique (primary plaster cast and secondary hard cast, or POPHC) were prospectively compared with PDCT using SC on upper and lower extremities.

Results

Compared with PDCT, the costs for POPHC were always higher: 138% for upper arm casts, 142% for lower arm and scaphoid casts, 219% for ankle joint casts, 157% for ankle splints, 336% for first-toe bandage/orthesis, and 289% for geisha shoes.

Conclusion

The procedure using PDCT with SC can contribute to cost savings and improve patient comfort.