Fiberglass Cast Research Articles

Short and long-arm fiberglass cast immobilization for displaced distal forearm fractures in children: a randomized controlled trial

PurposeThe aim of this study was to investigate whether short-arm fiberglass cast (SAC) immobilization provides fracture stabilization comparable to that of long-arm cast (LAC) treatment of displaced distal forearm fractures after closed reduction in paediatric patients.MethodsA prospective, randomized, controlled trial of children aged four to 16 years (mean 9.9 years) was designed with a sample of 120 children, whose size was set a priori, with 60 treated with SAC and 60 with LAC. The primary outcome was fracture stability and rate of loss of reduction. The secondary outcome analysis evaluated duration of analgesic therapy, restriction in activities of daily life, and the duration until patients regained normal range of motion in the elbow.ResultsNo statistically significant differences were found between the two groups in loss of reduction or duration of analgesic therapy. In contrast, the duration until normal range of motion in the elbow was regained was significantly longer in the LAC group (median 4.5 days, P < 0.001). Restriction in activities of daily life did not differ significantly between the two groups except for the item “help needed with showering in the first days after trauma” (SAC 60%, LAC 87%, P = 0.001).ConclusionFracture immobilization with short-arm fiberglass cast in reduced distal forearm fractures is not inferior to long-arm casts in children four years and older, excluding completely displaced fractures. Furthermore, short-arm casting reduces the need for assistance during showering.Trial registrationNCT03297047, September 29, 2017

The Impact of Different Application Techniques on Fiberglass Casts: A Mechanical Experimental Study.

Cast immobilization is a part of treatment in most of the orthopaedic injuries. The fiberglass material has several advantages over plaster of Paris which makes it more preferable. Some techniques are frequently used in daily fiberglass cast application to ease molding, shorten curing time and increase stiffness. The aim of this study is to assess the effects of two techniques on fiberglass cast strength and curing time. A cruris model was prepared to mimic a patella tendon bearing (PTB) cast. Three groups were created for the study (n = 30 each). The casts in the first group were treated with foam soap during molding. The casts in the second group were wrapped with a wet bandage after application. The third group was the control group. The samples were mechanically tested in the 5th, 15th and 30thmin. Maximum load, elastic strength, and Young's modulus were assessed via 3-point bending. All data were compared using linear regression analysis and p < 0.05 was determined as statistical significance. The results showed statistically significant improvement in cast mechanics in the wet bandage group at full curing time by means of maximum load, elastic strength and Young's modulus (p < 0.0001). Although the foam soap group had higher values in the 5th and 15th min, there was no statistically significant difference from the control group at full curing time (p > 0.05). This study revealed that wet bandage wrapping over circular fiberglass casts improved the cast strength. The use of foam soap during fiberglass cast molding did not alter cast mechanics at full curing time.

Does the location of short-arm cast univalve effect pressure of the three-point mould?

PurposeForearm and distal radius fractures are among the most common fractures in children. Many fractures are definitively treated with closed reduction and casting, however, the risk for re-displacement is high (7% to 39%). Proper cast application and the three-point moulding technique are modifiable factors that improve the ability of a cast to maintain the fracture reduction. Many providers univalve the cast to accommodate swelling. This study describes how the location of the univalve cut impacts the pressure at three-point mould sites for a typical dorsally displaced distal radius fracture.MethodsWe placed nine force-sensing resistors on an arm model to collect pressure data at the three-point mould sites. Sensory inputs were sampled at 15 Hz. Cast padding and a three-point moulded short arm fibreglass cast was applied. The cast was then univalved on the dorsal, volar, radial or ulnar aspect. Pressure recordings were obtained throughout the procedure.ResultsA total of 24 casts were analyzed. Casts univalved in the sagittal plane (dorsal or volar surface) retained up to 16% more pressure across the three moulding sites compared with casts univalved in the coronal plane (radial or ulnar border).ConclusionMaintaining pressure at the three-point mould prevents loss of reduction at the fracture site. This study shows that univalving the cast dorsally or volarly results in less pressure loss at moulding sites. This should improve the chances of maintaining fracture reductions when compared with radial or ulnar cuts in the cast. Sagittal plane univalving of forearm casts is recommended.

Physiologic effects of long-term immobilization of the equine distal limb.

To describe the effects of distal limb immobilization and remobilization in the equine metacarpophalangeal joint. Randomized, prospective experimental study. Eight healthy, skeletally mature horses. One forelimb of each horse was immobilized in a fiberglass cast for 8 weeks; this was followed by 12 weeks of a treadmill-based training program after the cast had been removed. Clinical examinations, radiography, computed tomography (CT), nuclear scintigraphy, MRI, and histomorphometry were used to examine the third metacarpal (MC3), proximal phalanx, proximal sesamoid bones, and associated soft tissues in each horse. Serum and synovial fluid were collected for biomarker analyses. Distal limb immobilization resulted in persistent lameness (P < .001), effusion (P = .002), and a decreased range of motion (P = .012) as well as radiographically visible fragments (P = .036) in the cast forelimb. Bone density was decreased (P < .001) in MC3 according to CT, and trabecular bone fluid was increased (P < .001) according to MRI in the cast forelimb. The cast forelimbs had a change (P = .009) in the appearance of the deep digital flexor tendon according to MRI immediately after removal of the cast. Numerous clinical, radiographic, CT, and MR abnormalities were visible at the end of the study period. Eights weeks of cast immobilization induced changes in bone, cartilage, and periarticular soft tissues that were not reversed after 12 weeks of remobilization. Cast application should be used judiciously in horses with musculoskeletal injuries, balancing appropriate stabilization with potential morbidity secondary to cast placement.

Test of Strength: Figure-of-Eight versus Spiral Wrapping Technique for Fiberglass Casts.

Pediatric fractures are a common injury, and treatment often includes cast immobilization. For pediatric patients being treated in a cast, cast damage is among the most common reasons patients return to the emergency room. The figure-of-eight wrapping technique interdigitates layers of fiberglass which may create a stronger cast. The aim of this study was to assess the strength of the figure-of-eight wrapping technique in comparison to the spiral wrapping technique. A total of 10 casts were wrapped with a three-inch fiberglass using the spiral technique and 10 casts were wrapped using the figure-of-eight technique. Each cast was then subjected to a three-point bending test and loaded until failure using an Instron machine. The figure-of-eight technique had an average load to failure of 278.2 + 27.6 N/mm which was similar to the spiral technique’s load to failure of 281.2 + 25.4 N/mm (p=0.795). Prior to normalizing for thickness, the load to failure of the figure-of-eight technique was 949.8 + 109.5 N, which was significantly higher than the spiral technique of 868.2 + 65.1 N (p=0.038). The figure-of-eight casts were slightly thicker than the spiral casts (average 0.3 mm, p=0.004). This suggests that the thickness of the fiberglass cast may improve the strength. The figure-of-eight wrapping technique had similar biomechanical characteristics to spiral wrapping techniques. Providers should wrap in whichever technique they feel most comfortable performing as there is no difference in strength of the cast. If a stronger cast is desired, then thickness of the cast can be increased.

Woodcast versus standard casting material for the immobilization of nonoperatively treated distal radial fractures

Distal radial fractures are the most common fracture sustained by the adult population. Most can be treated using cast immobilization without the need for surgery. The aim of this study was to assess the feasibility of a definitive trial comparing the commonly used fibreglass cast immobilization with an alternative product called Woodcast. Woodcast is a biodegradable casting material with theoretical benefits in terms of patient comfort as well as benefits to the environment. This was a multicentre, two-arm, open-label, parallel-group randomized controlled feasibility trial. Patients with a fracture of the distal radius aged 16 years and over were recruited from four centres in the UK and randomized (1:1) to receive a Woodcast or fibreglass cast. Data were collected on participant recruitment and retention, clinical efficacy, safety, and patient acceptability. Over an eight-month period, 883 patients were screened, 271 were found to be eligible, and 120 were randomized. Patient-reported outcome measures were available for 116 (97%) of participants at five weeks and 99 (83%) at three months. Clinical outcomes and patient acceptability were similar between the two interventions and no serious adverse events were reported in either intervention arm. Both interventions were deemed efficacious and safe in the cohort studied. This study showed that a definitive study comparing Woodcast and fibreglass was feasible in terms of patient recruitment and retention. Cite this article: Bone Joint J 2020;102-B(1):48-54.

Prognostic Factors Associated with Successful Outcome of Metacarpal and Metatarsal Fractures Repaired Using External Coaptation in Bovines

The objective of this study was to evaluate the various prognostic factors affecting outcome of metacarpal and metatarsal fracture repaired using external coaptation (straight or ‘U’ shaped aluminium splints and fibreglass cast) in bovine. The study investigated 100 bovines (37 buffaloes and 63 cattle) with 103 fractures (3 cattle with bilateral metacarpal fracture) presented during one year of study. Out of these, 10 were euthanized prior to the treatment, 23 died during the course of treatment and 7 were lost to follow up. Thus, out of the remaining 60 bovines with 61 fractures; 35 cattle with 36 fractures (10 metacarpal and 26 metatarsal) and 25 buffaloes (19 metacarpal and 6 metatarsal) were evaluated for the survival outcome of fractures. Cattle with metacarpal or metatarsal fractures were found to be about two times more prone to become open leading to unfavourable outcome (recumbency and death) as compared to that of buffaloes. The survival outcome as healed fracture of closed metacarpal and metatarsal, irrespective of species, was 100% and it was 33% more than that of the open fractures. In conclusion, the aluminium ‘U’ shaped splint with fiberglass cast was found to be suitable and economical method for the management of metacarpal /metatarsal fractures in adult cattle and buffaloes; whereas for the young and light weight bovines side splints with fiberglass cast involving hoof was recommended. The age and weight of animal, duration and cause of fracture, quality of first aid provided and radiographic type of fracture influenced the occurrence of open fractures, mortality and the survival outcome of metacarpal and metatarsal fractures repaired using external coaptation in bovines.

What’s New in Orthopaedic Trauma

What’s New in Orthopaedic Trauma

A Biomechanical Comparison of Fiberglass Casts and 3-Dimensional-Printed, Open-Latticed, Ventilated Casts.

Background: The aim of this study was to quantify the stabilizing properties of a 3-dimensional (3D)-printed short-arm cast and compare those properties with traditional fiberglass casts in a cadaveric subacute distal radius fracture model. Methods: A cadaveric subacute fracture model was created in 8 pairs of forearms. The specimens were equally allocated to a fiberglass cast or 3D-printed cast group. All specimens were subjected to 3 biomechanical testing modalities simulating daily life use: flexion and extension of digits, pronation and supination of the hand, and 3-point bending. Between each loading modality, radiological evaluation of the specimens was performed to evaluate possible interval displacement. Interfragmentary motion was quantified using a 3D motion-tracking system. Results: Radiographic assessment did not reveal statistically significant differences in radiographic parameters between the 2 groups before and after biomechanical testing. A statistically significant difference in interfragmentary motion was calculated with the 3-point bending test, with a mean difference of 0.44 (±0.48) mm of motion. Conclusions: A statistically significant difference in interfragmentary motion between the 2 casting groups was only identified in 3-point bending. However, the clinical relevance of this motion remains unclear as the absolute motion is less than 1 mm. The results of this study show noninferiority of the 3D-printed casts compared with the traditional fiberglass casts in immobilizing a subacute distal radius fracture model. These results support the execution of a prospective randomized clinical trial comparing both casting techniques.

Circulating casts of the Coatlicue : Mariana Castillo Deball’s unearthing of the Aztec earth goddess’s history of reproduction and display

This essay delves into casts of the Aztec earth goddess, the Coatlicue, through the lens of a sculpture, No solid form can contain you (2010), by the contemporary Mexican artist Mariana Castillo Deball. In this sculpture, Castillo Deball created a fibreglass cast of the Coatlicue and placed it on the floor. These artistic decisions highlighted two important and yet understudied aspects of the Aztec monument – its frequent disinterment and reburial, and subsequent reproduction and circulation. This article traces these connected paths of the Coatlicue, from the cycles of unearthing to its circulation through publications and plaster cast copies. To theorize the importance of these copies, this article draws on a recent article by Bruno Latour and Adam Lowe. Major political shifts within the Mexican Republic had important consequences for the status of Aztec monuments such as the Coatlicue, as presidents Benito Juárez and Porfirio Díaz recuperated them as evidence of a powerful ancient civilization. Once feared as a ‘monstrous’ icon, the Coatlicue was transformed into a symbol of national identity and occupied a place of pride in the museum. In No solid form can contain you, Castillo Deball questions the political and museological apparatuses that have dictated the status of the Coatlicue. The essay argues that her work operates within a framework set out by Erica Segre whereby Mexican artists integrated images of the pre-Columbian past to ‘interrogate identity’. To create the work, Castillo Deball used the same strategies of replication and circulation, though by presenting the work with seams left unfinished and lying on the floor, she gestured towards the constructed nature of replicas and their history of display.

The Correction of Systematic Error due to Plaster and Fiberglass Casts on HR-pQCT Bone Parameters Measured In Vivo at the Distal Radius

Due to difficulty assessing healing of distal radius fractures using conventional radiography, there is interest in using high resolution peripheral quantitative computed tomography (HR-pQCT) to track healing at the microarchitectural level. Unfortunately, the plaster-of-Paris and fiberglass casts used to immobilize fractures affect HR-pQCT measurements due to beam hardening, and increased noise. The challenge is compounded because casts have variable thickness, and an individual patient will often have their cast changed 2–3 times during the course of treatment. This study quantifies the effect of casts within a clinically relevant range of thicknesses on measured bone parameters at the distal radius, and establishes conversion equations to correct for systematic error in due to cast presence. Eighteen nonfractured participants were scanned by HR-pQCT in three conditions: no cast, plaster-of-Paris cast, and fiberglass cast. Measured parameters were compared between the baseline scan (no cast) and each cast scan to evaluate if systematic error exists due to cast presence. A linear regression model was used to determine an appropriate conversion for parameters that were found to have systematic error. Plaster-of-Paris casts had a greater range of thicknesses (3.2–9.5 mm) than the fiberglass casts (3.0–5.4 mm), and induced a greater magnitude of systematic error overall. Key parameters of interest were bone mineral density (total, cortical, and trabecular) and trabecular bone volume fraction, all of which were found to have systematic error due to presence of either cast type. Linear correlations between baseline and cast scans for these parameters were excellent (R2 > 0.98), and appropriate conversions could be determined within a margin of error less than a ±6% for the plaster-of-Paris cast, and ±4% for the fiberglass cast. We have demonstrated the effects of cast presence on bone microarchitecture measurements, and presented a method to correct for systematic error, in support of future use of HR-pQCT to study fracture healing.

Impact of Casting and Splinting Manipulations on Below-Dressing Pressures: An Experimental Model.

We tested how different applications of casts and splints affect underlying below-dressing pressures and how these dressings respond to swelling. A 3-in polyvinyl chloride pipe with an attached 100 mL saline bag to the outer surface was used to simulate a human forearm. A pressure transducer was attached to the bag and connected to a monitor providing continuous pressure measurements. Either a circumferential fiberglass cast or single-sided plaster splint was applied around the bag. To simulate the dressing's compliance to soft tissue swelling, change in pressure was measured after 25 mL of saline was injected into the bag. Compliance was determined by calculating change in volume over change in pressure as volume was added. In our 150 mL model, cast bivalving reduced pressure up to 28%, and splitting the cotton padding of a splint reduced pressures up to 33%. The mean compliance (ability to accommodate swelling) across all volume intervals was 182% greater in a bivalved cast versus a cast and 21% greater in a cotton-split splint versus a splint. Below-dressing pressure of a tightly wrapped elastic bandage was up to 2.76× greater than a medium tension bandage and up to 6.44× greater than a loosely applied bandage. A splint with real cotton padding had a 28% greater pressure than a splint with synthetic soft-roll padding. Splitting a dressing, utilizing synthetic cotton padding, and applying an elastic bandage cautiously can help reduce surface pressures and allow the construct to be more accommodating to soft tissue swelling.

Conventional vs 3-Dimensional Printed Cast Wear Comfort

Background: The objective of this study was to determine the functionality of 3-dimensional (3D) printed orthoses for upper extremity immobilization compared with conventional immobilization. Methods: Twelve healthy volunteers were fitted with a 3D custom printed short arm cast and a short arm fiberglass cast in separate sessions. The Jebsen Hand Function Test (JHFT) was used to test function and dexterity in each cast. All volunteers completed a modified version of the Patient-Rated Wrist Evaluation (PRWE). Skin complications were recorded. Results: There were no significant differences during the JHFT between casts, although one-third of the participants in the 3D cast could perform the tasks in a normal time, which they could not in the fiberglass cast. The average PRWE function score was lower in the 3D cast group than in the fiberglass group (45.5 vs. 80.8). Minor skin irritation was noted in 42% of patients in the fiberglass cast group compared with only 1 patient (8%) in the 3D cast group. One patient in the fiberglass group required a cast change due to inappropriate fit. Conclusions: Both casting techniques demonstrate similar objective function based on the JHFT. Patient satisfaction, comfort, and perceived function are superior in the 3D printed casts.

Evaluation of the effects of initial water temperature and curing time on fiberglass cast strength.

To determine the effects of water temperature and cure time on cast strength. Prospective randomized experimental study. Two water temperatures were tested, 23°C (cold) and 42°C (warm). Cast constructs were made of 4-inch fiberglass casting material over a rubber mandrel. Each construct was divided into 3 segments and tested in 4-point bending at 0.5, 1, and 24 hours. Stiffness and bending moment, cumulative energy, and angular deformation at yield and failure were recorded and analyzed by using repeated measures ANOVA. Mean time ± SD to complete the construct was 2.2 ± 0.8 and 2.3 ± 0.6 minutes for warm and cold water, respectively. Warm water and longer cure times produced constructs with greater stiffness (23.05 vs 20.88 newton-meter degrees [Nm°] at 0.5 hours), bending moment (121.75 vs 107.31 Nm° at 0.5 hours), and cumulative energy (557.33 vs 428.89 Nm° at 1 hour) at yield and failure. Longer cure time significantly increased angular deformation of rods at failure; however, water temperature did not. In general, the strongest casts were produced with warm water and after curing for 24 hours. Fiberglass casts continued to gain strength for at least 24 hours. Use of warm water increased the rate of curing, resulting in stronger constructs at earlier time points. Use of warm water is recommended to initiate fiberglass cast curing, especially if the casted limb will be loaded soon after cast application.

An audit of complications of fiberglass cast and hybrid cast for fractures of the foot, ankle and forearm in a Swedish emergency department

Patients of all ages present to the Emergency Department (ED) with fractures that require immobilization using a cast. Various casting materials are used, all with advantages and disadvantages and there are considerable risks associated with fracture management using cast immobilization. The frequency and severity of complications from fiberglass or hybrid casts applied in the emergency setting has not previously been studied.The aim of this audit was to describe all the complications that occurred within 30 days in patients who had a fiberglass cast applied for immobilization of uncomplicated, non-angulated fractures of the foot, ankle or forearm.A retrospective care record audit was conducted that included 430 patients. ResultsThe most common complications found were skin complications and cast related problems. No severe complications (e.g. compartment syndrome, venous thromboembolism or infection) were found. ConclusionFiberglass casts did not cause severe complications in this group of patients with uncomplicated fractures of the extremities. However, 25% of the patients experienced some form of complication. Interventions are needed that minimize the frequency of complications. As with all healthcare interventions, it is crucial that staff applying casts and providing follow-up care are competent. If casts are applied correctly and the patient is well informed and concordant, complications can be avoided.

Early Functional and Radiological Outcomes Between Plaster Cast and Fiberglass Cast in Stable Thoracolumbar Burst Fracture

Introduction: Burst fracture results from compression failure of both the anterior and middle columns under substantial axial loads. Conservative treatment was a method of treatment for fractures without neurological deficit. This cross sectional study was designed to evaluate the functional and radiological outcome of patient with thoracolumbar burst fracture treated conservatively. Methods: 40 cases were recruited from January 2013 till December 2015. They were followed-up with minimum period of 1 year and evaluated for the functional (Oswetry Disbility Index) and radiological outcomes (kyphotic angle deformity and anterior body compression). Results: 20 patients were treated with body cast made form plaster of Paris and remaining 20 patients with fiberglass cast. In plaster of Paris group, mean kyphotic angle deformity at last follow up was 16.60 ± 2.95 with a mean improvement 4.45 degree and anterior body compression at last follow up was 30.35% ± 10.2 with mean improvement of 9.30%. In fiberglass group, mean kyphotic angle deformity at last follow up was 15.55 ± 3.38 with a mean improvement 7.25 degree and anterior body compression at last follow up was 25.90% ± 7.81 with mean improvement of 3.45%. The functional outcome showed Oswetry Disability Index (ODI) score in plaster of Paris group was 23.70 (SD = 7.82) and in fiberglass group was 18.50 (SD = 5.94). Conclusions: Application of body cast using a fiberglass material give better radiological outcome hence less pain, more functional and higher patient’s satisfaction as compared to plaster of Paris.

A Removable Long-arm Soft Cast to Treat Nondisplaced Pediatric Elbow Fractures: A Randomized, Controlled Trial.

The ideal type of immobilization for nondisplaced pediatric elbow fractures has not been established. We hypothesized that the use of a long-arm cylinder made of soft cast material will result in similar outcomes to those obtained with a traditional long-arm hard cast. We randomly assigned 100 consecutive children who presented with a closed, nondisplaced, type I supracondylar humeral fracture or an occult, closed, acute elbow injury, to 1 of 2 groups: group A (n=50) received a long-arm, traditional fiberglass (hard) cast. Group B (n=50) received a long-arm, soft fiberglass cast. After 4 weeks, the cast was removed in group A by a member of our staff using a cast saw, and in group B by one of the patient's parents by rolling back the soft fiberglass material. We compared the amount of fracture displacement and/or angulation, recovery of range of motion, elbow pain, and patient satisfaction. There were no instances of unplanned removal of the cast by the patient or parent. No evidence of fracture displacement or angulation was seen in either group. The final carrying angle of the affected elbow was nearly identical of that of the normal, contralateral elbow in both groups (P=0.64). At the latest follow-up appointment, elbows in groups A and B had a similar mean arc of motion (156 vs. 154 degrees; P=0.45), and had achieved identical relative arc of motion of 99.6% and 99.5% of that of the normal, contralateral side, respectively (P=0.94). Main pain scores were low and comparable over the study period. All patients in both groups reported the highest rate of satisfaction at the eighth week of follow-up. The results indicate that children with nondisplaced supracondylar humeral fractures can be successfully managed with the use of a removable long-arm soft cast, maintaining fracture alignment and resulting in comparable rates of range of motion, pain, and patient satisfaction. The use of a removable immobilization that can reliably maintain fracture alignment and result in similar outcomes, while minimizing the risk of noncompliance, could be advantageous. Although we elected to remove the soft cast during a scheduled follow-up, it appears that such immobilization could be removed easily and safely at home, potentially resulting in a lower number of patient visits, decreased health care costs, and higher patient/parent satisfaction. Level I.

A simple technique to prolong molding time during application of a fiberglass cast: An in vitro study.

Casting is routinely used for acute and post-operative immobilization and remains a cornerstone in the non-operative management of fractures and deformities. The application of a properly fitted and wellmolded cast, especially for a trainee, can be challenging. We present a simple method of prolonging cure time of fiberglass cast — placing ice in the dip water. Eight-ply, fiveinch fiberglass cast was circumferentially applied to an aluminum-wrapped cardboard cylinder. An electronic, 2-channel temperature sensor (TR-71wf Temp Logger, T&D Corporation, Matsumoto, Japan), accurate to 0.1ºC and accurate to ±0.3ºC, was placed between the fourth and fifth layers of fiberglass. Thirty total casts were tested using 9±1ºC (cold), 22±1ºC (ambient), and 36±1ºC (warm) dip water. Room temperature was maintained at 24±1ºC. Cast temperatures were measured during the exothermic reaction generated by the cast curing. Peak temperatures and cure times were recorded. Cure time was defined as the point of downward deflection on the timetemperature curve immediately after peak. Cure and peak temperatures were compared among groups using analysis of variance. Mean cure time was 3.5±0.1 minutes for warm water, 5.0±0.4 minutes for ambient water and 7.0±0.5 minutes for cold water. Peak temperature, measured between layers 4 and 5 of the cast material, was 36.6±0.8ºC for warm water, 31.1±1.4ºC for ambient water and 25.2±0.5ºC for cold water. Cold afforded, on average, an additional 2 minutes (40% increase) in cure time compared to ambient water and an additional 3.5 minutes (100% increase) compared to warm water. Cure time differences were significant (P<0.001) for all groups, as were peak temperature differences (P<0.001). Temperatures concerning for development of burns were never reached. Utilizing iced dip water when casting is a simple and effective method to prolong the time available for cast application. Orthopedic residents and trainees may find this useful in learning to fabricate a high quality cast. For the experienced orthopedic surgeon, this method eliminates the need to bridge longlimb casts and facilitates the application of complex casts.

Use of pressure mapping for quantitative analysis of pressure points induced by external coaptation of the distal portion of the pelvic limb of dogs

OBJECTIVE To quantitatively measure the amount of pressure induced at the calcaneus and cranial tibial surface of dogs by use of 2 cast configurations. ANIMALS 13 client- or student-owned dogs. PROCEDURES Pressure sensors were placed over the calcaneus and cranial tibial surface. Dogs then were fitted with a fiberglass cast on a pelvic limb extending from the digits to the stifle joint (tall cast). Pressure induced over the calcaneus and proximal edge of the cast at the level of the cranial tibial surface was simultaneously recorded during ambulation. Subsequently, the cast was shortened to end immediately proximal to the calcaneus (short cast), and data acquisition was repeated. Pressure at the level of the calcaneus and cranial tibial surface for both cast configurations was compared by use of paired t tests. RESULTS The short cast created significantly greater peak pressure at the level of the calcaneus (mean ± SD, 0.2 ± 0.07 MPa), compared with peak pressure created by the tall cast (0.1 ± 0.06 MPa). Mean pressure at the proximal cranial edge of the cast was significantly greater for the short cast (0.2 ± 0.06 MPa) than for the tall cast (0.04 ± 0.03 MPa). CONCLUSIONS AND CLINICAL RELEVANCE A cast extended to the level of the proximal portion of the tibia caused less pressure at the level of the calcaneus and the proximal cranial edge of the cast. Reducing the amount of pressure at these locations may minimize the potential for pressure sores and other soft tissue injuries.

Radiographic evaluation of acute distal radius fracture stability: A comparative cadaveric study between a thermo-formable bracing system and traditional fiberglass casting

BackgroundDistal radius fractures are common musculoskeletal injuries and many can be treated non-operatively with cast immobilization. A thermo-formable brace has been developed for management of such fractures, but no data exist regarding its comparative stabilizing efficacy to fiberglass casting. MethodsA worst-case distal radius fracture was created in 6 cadaveric forearms. A radiolucent loading fixture was created to apply cantilever bending/compression loads ranging from 4.5N to 66.7N across the simulated fracture in the: (1) non-stabilized, (2) braced; and (3) casted forearms, each forearm serving as its own control. Fracture fragment translations and rotations were measured radiographically using orthogonal radiographs and a 2D-3D, CT-based transformation methodology. FindingsUnder 4.5N of load in the non-stabilized condition, average sagittal plane rotation and 3D center of mass translation of the fracture fragment were 12.3° and 5.3mm, respectively. At the 4.5N load step, fragment rotation with the brace (avg. 0.0°) and cast (0.1°) reduced sagittal plane rotation compared to the non-stabilized forearm (P<0.001). There were no significant differences in measured sagittal plane fracture fragment rotations or 3D fragment translations between the brace or cast at any of the four load steps (4.5N, 22.2N, 44.5N, and 66.7N, P≥0.138). InterpretationIn this in vitro radiographic study utilizing 6 cadaveric forearms with simulated severe-case, unstable and comminuted distal radius fractures, the thermo-formable brace stabilized the fracture in a manner that was not radiographically or biomechanically different from traditional fiberglass casting. Study results support the use of the thermo-formable brace clinically.