A clinical study of patients with pre-tibial lacerations at King's College Hospital and Guy's Hospital, London, England, compared a non-adhesive dressing with Synthaderm. Treatment was randomly allocated. At King's College Hospital, deep and superficial lacerations were equally distributed, the median time to healing with Synthaderm was significantly (P less than 0.02) reduced; and the median rate of healing (mm/day) was significantly (P less than 0.01) better. At Guy's Hospital, larger and wider wounds were unequally distributed, with fewer in the control group; in the Synthaderm group, the median rate of healing was increased. In both centres, the clinical impression was that Synthaderm reduced nursing dressing time and a better scar resulted. Synthaderm improved the rate of healing in pre-tibial lacerations.
Nonunion of long bones is a difficult clinical problem and challenges the clinical acumen of surgeons. Multiple surgical or nonsurgical modalities have been used to treat nonunions. Noninvasive pulsed electromagnetic stimulation is an entity known to affect the piezoelectric phenomenon of bone forming cells. We conducted a study on 45 long-bone fractures of tibia treated by pulsed electromagnetic stimulation, which are analyzed and reported.
Materials and Methods:
A total of 45 tibial fractures with established atrophic nonunion were enrolled between 1981 and 1988. All the patients had abnormal mobility and no or minimal gap at fracture site with no evidence of callus formation across the fracture site. The patients' age ranged between 24 and 68 years; 40 were men and 5 were women. All patients having evidence of infection, implant in situ, and gap nonunions were excluded from study. Pulsed electromagnetic stimulation was given using above-knee plaster of Paris cast (0.008 Weber/m2 magnetic field was created for 12 h/day). The average duration for pulsed electromagnetic stimulation (PEMS) therapy was 8.35 weeks, with the range being 6–12 weeks. The cases were evaluated at 6 weeks and subsequently every 6-weekly interval for clinical and radiological union. The withdrawal of therapy was decided as per clinicoradiological evidence of union.
All but three patients showed evidence of union. About 35% (n = 16) cases showed union in 10 weeks, and 85%(n = 38) cases showed union in 4 months. The average duration of therapy using PEMS was 8.35±0.48 weeks, and the average duration of immobilization was 3.02 ± 0.22 months. Three cases that did not show evidence of union were poorly compliant for the apparatus of PEMS.
PEMS is a useful noninvasive modality of treatment for difficult nonunion of long bones.
Nonunion; pulsed electromagnetic stimulation; tibial diaphyseal fractures
Periprosthetic fractures associated with total knee arthroplasty are rare but present a challenging problem particularly when associated with revision arthroplasty. Fractures around tibial stems are particularly difficult with no accepted technique in their management. This case describes a tibial periprosthetic fracture following a revision knee arthroplasty which was successfully managed with a Pulsed ElectroMagnetic Field bone stimulation device. We believe this to be first reported use of a bone stimulation device in this clinical environment.
We made a comparative cohort study in patients suffering from tibial pseudoarthrosis, all of whom were treated by intramedullary nailing. We divided patients into two groups: one treated by intramedullary nailing only (control group) and the other by intramedullary nailing combined with pulsed electromagnetic fields (PEMFs). The study included 57 cases of tibial pseudoarthrosis in 57 patients from February 1987 to February 2002. Pseudoarthrosis was treated surgically in all cases (Grosse-Kempf dynamic intramedullary nailing). This was combined with PEMFs in 22 cases. The average age was 38.3 years (range 14–89 years) and the average duration of follow-up was 27.2 months (range 12–48 months). Forty-nine fractures (86%) healed and eight (14%) did not. Of the group treated with PEMFs, 20 (91%) healed and two (9%) did not; from the group that did not receive PEMF (35), 29 (83%) healed compared to six (17%) that did not. The relationship between union and use of PEMFs, and between time to union and use of PEMFs was clinically relevant. PEMFs are useful when treating tibial pseudoarthrosis. Its noninvasive nature means that there are more complication-free unions.
Pulsed electromagnetic fields (PEMF) stimulation for the treatment of bone nonunion or delayed union have been in use for several years, but on a limited basis. The aim of this study was to assess the overall efficacy of the method in tibial delayed unions and nonunions and identify factors that could affect the final outcome.
We prospectively reviewed 44 patients (27 men) with a mean age of 49.6 ± 18.4 years that received PEMF therapy due to tibial shaft delayed union or nonunion. In all cases, fracture gap was less than 1 cm and infection or soft tissue defects were absent.
Fracture union was confirmed in 34 cases (77.3%). No relationship was found between union rate and age (p = 0.819), fracture side (left or right) (p = 0.734), fracture type (simple or comminuted, open or closed) (p = 0.111), smoking (p = 0.245), diabetes (p = 0.68) and initial treatment method applied (plates, nail, plaster of paris) (p = 0.395). The time of treatment onset didn’t affect the incidence of fracture healing (p = 0.841). Although statistical significance was not demonstrated, longer treatment duration showed a trend of increased probability of union (p = 0.081).
PEMF stimulation is an effective non-invasive method for addressing non-infected tibial union abnormalities. Its success is not associated with specific fracture or patient related variables and it couldn’t be clearly considered a time-dependent phenomenon.
PEMF; Tibia; Fracture; Nonunion; Delayed union
Objective: To compare the effects of low-intensity pulsed ultrasound (LIPUS) or pulsed electromagnetic fields (PEMF) on fracture healing through a systematic review of original, English-language clinical research reports.
Data Sources: A search of MEDLINE, Physiotherapy Evidence Database (PEDro), and ProQuest to identify clinical trials of LIPUS or PEMF with fractures in humans, written in English, published from 1966 through 2004. Key words were ultrasound, fracture, tibial, electric current, and healing.
Study Selection: After search limits were applied, 17 papers were assessed independently by 2 reviewers. Papers were excluded from consideration if they lacked (1) random allocation of treatments, (2) inclusion of skeletally mature patients of either sex with a current fracture, (3) blinding of both the patient and the assessors as to treatment group, (4) administration of either LIPUS or PEMF treatments to one of the treatment groups, or (5) assessment of time to fracture healing or proportion of fractures healed, as determined radiographically, clinically, or both.
Data Extraction: Eight trials met the inclusion criteria. Methodologic quality of all trials was assessed using the PEDro criteria. Outcome measures were tabulated.
Data Synthesis: Heterogeneity among studies precluded direct comparison of the efficacy of LIPUS to that of PEMF.
Conclusions: The studies we included in our review were of generally high methodologic quality. The evidence suggests that LIPUS may speed healing of acute tibial fractures. Comparison studies of these modalities are needed to guide treatment of fractures sustained by athletic individuals.
nonunion; modalities; radiographic healing; clinical healing
Environmental exposure to man-made electromagnetic fields has been steadily increasing with the growing demand for electronic items that are operational at various frequencies. Testicular function is particularly susceptible to radiation emitted by electromagnetic fields.
This study aimed to examine the therapeutic effects of a pulsed electromagnetic field (100 Hz) on the reproductive systems of male Wistar rats (70 days old).
The experiments were divided into five groups: microwave sham, microwave exposure (2.45 GHz), pulsed electromagnetic field sham, pulsed electromagnetic field (100 Hz) exposure, and microwave/pulsed electromagnetic field exposure. The animals were exposed for 2 hours/day for 60 days. After exposure, the animals were sacrificed, their sperm was used for creatine and caspase assays, and their serum was used for melatonin and testosterone assays.
The results showed significant increases in caspase and creatine kinase and significant decreases in testosterone and melatonin in the exposed groups. This finding emphasizes that reactive oxygen species (a potential inducer of cancer) are the primary cause of DNA damage. However, pulsed electromagnetic field exposure relieves the effect of microwave exposure by inducing Faraday currents.
Electromagnetic fields are recognized as hazards that affect testicular function by generating reactive oxygen species and reduce the bioavailability of androgen to maturing spermatozoa. Thus, microwave exposure adversely affects male fertility, whereas pulsed electromagnetic field therapy is a non-invasive, simple technique that can be used as a scavenger agent to combat oxidative stress.
Microwave; Caspases; Creatine kinase; Testosterone; Infertility
The scaphoid bone is the most commonly fractured of the carpal bones. In the Netherlands 90% of all carpal fractures is a fracture of the scaphoid bone. The scaphoid has an essential role in functionality of the wrist, acting as a pivot. Complications in healing can result in poor functional outcome. The scaphoid fracture is a troublesome fracture and failure of treatment can result in avascular necrosis (up to 40%), non-union (5-21%) and early osteo-arthritis (up to 32%) which may seriously impair wrist function. Impaired consolidation of scaphoid fractures results in longer immobilization and more days lost at work with significant psychosocial and financial consequences.
Initially Pulsed Electromagnetic Fields was used in the treatment of tibial pseudoarthrosis and non-union. More recently there is evidence that physical forces can also be used in the treatment of fresh fractures, showing accelerated healing by 30% and 71% reduction in nonunion within 12 weeks after initiation of therapy. Until now no double blind randomized, placebo controlled trial has been conducted to investigate the effect of this treatment on the healing of fresh fractures of the scaphoid.
This is a multi center, prospective, double blind, placebo controlled, randomized trial. Study population consists of all patients with unilateral acute scaphoid fracture. Pregnant women, patients having a life supporting implanted electronic device, patients with additional fractures of wrist, carpal or metacarpal bones and pre-existing impairment in wrist function are excluded. The scaphoid fracture is diagnosed by a combination of physical and radiographic examination (CT-scanning).
Proven scaphoid fractures are treated with cast immobilization and a small Pulsed Electromagnetic Fields bone growth stimulating device placed on the cast. Half of the devices will be disabled at random in the factory.
Study parameters are clinical consolidation, radiological consolidation evaluated by CT-scanning, functional status of the wrist, including assessment by means of the patient rated wrist evaluation (PRWE) questionnaire and quality of life using SF-36 health survey questionnaire.
Primary endpoint is number of scaphoid unions at six weeks, secondary endpoints are time interval to clinical and radiological consolidation, number of non-unions, functional status at 52 weeks and non-adherence to the treatment protocol.
Netherlands Trial Register (NTR): NTR2064
The ability to stimulate bone repair, heal non-unions, or restore lost segments of bone is a common goal among orthopaedic surgeons, trauma surgeons, and scientists who investigate wound healing responses. The stimulation of bone repair has been reported using biophysical means such as electromagnetic fields, low-intensity pulsed ultrasound and extracorporeal shockwave therapy. Reported studies on the use of these modalities suggest beneficial effects but the quality of the evidence and high between-study heterogeneity leave the impact of these biophysical stimuli on bone repair uncertain.
New biotechnologies to enhance skeletal repair have focused on growth factors, osteoinductive molecules, and, more recently, autologous adult bone marrow stem cells. Recent randomized, placebo-controlled clinical trials using recombinant human fibroblast growth factor-2 for the treatment of tibial shaft fractures, and platelet-derived growth factor for the treatment of ankle fractures have yielded potentially interesting results. More data are needed to confirm these findings. Investigations using prostaglandin EP-2 receptor agonists to enhance tibia shaft fracture healing are also under way.
Clinicians and scientists have utilized autologous bone marrow for over a century. Unprocessed preparations have shown uneven results with regard to their ability to enhance bone repair. Recent data, however, demonstrating the use of autologous bone marrow stem cells in a concentrated manner have been very encouraging. Injection of bone marrow aspirate concentrate into non-unions and in conjunction with local bone for the enhancement of spinal fusion have shown impressive results.
Perhaps the most well-investigated biotechnology for the enhancement of bone repair is the use of the bone morphogenetic proteins. BMP-2 and BMP-7 are now available as recombinant molecules and have been evaluated in both spinal and long-bone trauma applications. RhBMP-2 has demonstrated efficacy in the enhancement of single-level lumbar intervertebral body fusions and open (compound) tibia-shaft fractures. RhBMP-7 (also known as OP-1) has been shown to be effective in the treatment of recalcitrant non-unions of long bones. Fusion of the spine, however, in patients undergoing posterolateral fusions has been somewhat less successful. At this time, use of BMPs should be limited to only those applications approved by government regulatory bodies as off-label use has been associated with serious complications, such as the use of BMP-2 in the cervical spine causing airway obstruction.
Future biotechnologies to enhance bone repair are in development. One potential area of interest may be to target the Wnt signaling pathway in osteoblasts. Recent data suggesting the efficacy of Wnt proteins in the enhancement of skeletal healing suggest that this pathway may be worthy of further investigation. Although technologies for the enhancement of skeletal repair have focused on locally applied materials that are either implanted or injected, future technologies may focus on systemic means of enhancing skeletal repair. In particular, the presence of known human phenotypes associated with mutations in the receptor-ligand interactions that trigger this pathway suggests that modification of Wnt signaling may have a beneficial clinical impact when the appropriate agonist or antagonist is formulated in the appropriate way. A recent randomized, controlled trial using parathyroid hormone (1–34) to enhance the healing of distal radius fractures shows promise and may form the foundation for future investigations to develop systemic therapies for bone repair.
The aim of this study was to analyze the effect of high-energy extracorporeal shockwave therapy on tendon angiogenesis in the patellar tendons of rabbits. We sought to investigate whether different voltage and number pulses modify the angiogenesis pattern.
High-energy extracorporeal shockwave therapy is an option in the treatment of orthopedic diseases such as chronic tendonitis. Despite its potential clinical applicability, there have been few studies on this technique that examine both its clinical effectiveness and its effect on angiogenesis.
High-energy extracorporeal shockwave therapy was applied at the tibial insertion of the left patellar ligament in 30 rabbits that were separated into six groups that differed in terms of the voltage and number of pulses that were applied by high-energy extracorporeal shockwave therapy. The tibial insertion in the right legs of the animals was used as the control. After six weeks, we performed histological analysis on the region and quantified the number of blood vessels.
No significant differences in the number of blood vessels between the left and right patellar tendons were found within groups. Additionally, no significant differences in the number of blood vessels in the left patellar tendons were found between groups.
The application of high-energy extracorporeal shockwave therapy did not cause a change in vascularization in the patellar tendon in rabbits.
High-energy shock waves; Patellar ligament; Neovascularization; Animal model
Tendons function to transmit loads from muscle to move and stabilize joints and absorb impacts. Functionality of lacerated tendons is diminished, however clinical practice often considers surgical repair only after 50% or more of the tendon is lacerated, the “50% rule.” Few studies provide mechanical insight into the “50% rule.”
Method of Approach
In this study cyclic and static stress relaxation tests were performed on porcine flexor tendons before and after a 0.5, 1.0, 2.0, or 2.75mm deep transverse, mid-substance laceration. Elastic and viscoelastic properties, such as maximum stress, change in stress throughout each test, and stiffness, were measured and compared pre- and post-laceration.
Nominal stress and stiffness parameters decreased, albeit disproportionately in magnitude, with increasing percent loss of cross-sectional area. Conversely, mean stress at the residual area (determined using remaining intact area at the laceration cross-section) exhibited a marked increase in stress concentration beginning at 47.2% laceration using both specified load and constant strain analyses.
The marked increase in stress concentration beginning near 50% laceration provides mechanical insight into the “50% rule.” Additionally, a drastic decrease in viscoelastic stress parameters after only an 8.2% laceration suggests that time-dependent mechanisms protecting tissues during impact loadings are highly compromised regardless of laceration size.
Mechanics; tendon; laceration; viscoelasticity
Peripheral somatosensory circuits are known to respond to diverse stimulus modalities. The energy modalities capable of eliciting somatosensory responses traditionally belong to mechanical, thermal, electromagnetic, and photonic domains. Ultrasound (US) applied to the periphery has also been reported to evoke diverse somatosensations. These observations however have been based primarily on subjective reports and lack neurophysiological descriptions. To investigate the effects of peripherally applied US on human somatosensory brain circuit activity we recorded evoked potentials using electroencephalography and conducted functional magnetic resonance imaging of blood oxygen level-dependent (BOLD) responses to fingertip stimulation with pulsed US. We found a pulsed US waveform designed to elicit a mild vibration sensation reliably triggered evoked potentials having distinct waveform morphologies including a large double-peaked vertex potential. Fingertip stimulation with this pulsed US waveform also led to the appearance of BOLD signals in brain regions responsible for somatosensory discrimination including the primary somatosensory cortex and parietal operculum, as well as brain regions involved in hierarchical somatosensory processing, such as the insula, anterior middle cingulate cortex, and supramarginal gyrus. By changing the energy profile of the pulsed US stimulus waveform we observed pulsed US can differentially activate somatosensory circuits and alter subjective reports that are concomitant with changes in evoked potential morphology and BOLD response patterns. Based on these observations we conclude pulsed US can functionally stimulate different somatosensory fibers and receptors, which may permit new approaches to the study and diagnosis of peripheral nerve injury, dysfunction, and disease.
The acoustic lens of the Siemens Modularis electromagnetic (EM) shock wave lithotripter has been modified to produce a pressure waveform and focal zone more closely resembling that of the original Dornier HM3 device. Herein, we assess the newly designed acoustic lens in vivo in an animal model.
Materials and Methods
Stone fragmentation and tissue injury produced by the original and modified lenses of a Siemens lithotripter were evaluated in a swine model under equivalent acoustic pulse energy (~45 mJ) at 1 Hz pulse repetition frequency. Stone fragmentation was determined by the weight percent of stone fragments less than 2 mm. For tissue injury assessment, shock wave-treated kidneys were perfused, dehydrated, cast in paraffin wax and sectioned. Digital images were captured every 120 µm and processed to determine the functional renal volume damage.
After 500 shocks, stone fragmentation efficiency produced by the original and modified lenses was 48 ± 12% and 52 ± 17% (p=0.60), respectively. However, after 2000 shocks, the modified lens showed significantly improved stone fragmentation of 86 ± 10%, compared to 72 ± 12% for the original lens (p=0.02). Tissue injury caused by the original and modified lenses was minimal at 0.57 ± 0.44% and 0.25 ± 0.25% (p=0.27), respectively.
With lens modification, the Siemens Modularis lithotripter demonstrates significantly improved stone fragmentation with minimal tissue injury at clinically relevant acoustic pulse energy. This new lens design could potentially be retrofitted to existing lithotripters, thereby improving the effectiveness of EM lithotripters.
Lens modification; Electromagnetic Lithotripter; in vivo; Swine model
Establishing a means to prevent osteonecrosis after corticosteroid administration is an important theme. We asked whether pulsed electromagnetic field stimulation, a noninvasive treatment, could prevent osteonecrosis. Ninety rabbits were divided into four treatment groups: (1) exposure of 10 hours per day to electromagnetic stimulation for 1 week, followed by injection of methylprednisolone (20 mg/kg), and exposure of 10 hours per day to electromagnetism for a further 4 weeks (n = 40); (2) methylprednisolone injection only (n = 40); (3) no treatment (n = 5); and (4) exposure of 10 hours per day to electromagnetism for 5 weeks (n = 5). After 5 weeks, we harvested and histologically examined femurs bilaterally. The frequency of osteonecrosis was lower in the steroid-electromagnetism group (15/40) than in the steroid-only group (26/40). No necrotic lesions were found in the two control groups. We observed no clear effects of electromagnetism on the number, location, extent, and repair of necrotic lesions and intramedullary fat cell size in affected rabbits. Pulsed electromagnetic field stimulation reportedly augments angiogenesis factors and dilates blood vessels; these effects may lower the frequency of osteonecrosis. Exposure to pulsed electromagnetic field stimulation before corticosteroid administration could be an effective means to reduce the risk of osteonecrosis.
While the application of compressive joint loads and thigh muscle activity are associated with anterior tibial translation in vitro, less is known during early load acceptance in-vivo. We investigated the effects of increasing axial loads on anterior tibial translation and thigh muscle activity in healthy knees during transition from non-weight bearing to early weight bearing.
Participants (11 Male, 11 Female) underwent 20%, 40%, and 60% body weight acceptance trials at 20° knee flexion while electromagnetic sensors measured anterior tibial translation (mm), and surface electromyography recorded quadriceps and hamstring muscle onset times (ms) and amplitudes (% maximal voluntary isometric contraction). Repeated measures ANOVA compared values across loads. Pearson correlations examined relationships between anterior tibial translation and muscle onset times and amplitudes within each load.
As load increased, anterior tibial translation (Mean (standard deviation)) (20%=4.7(1.7)mm < 40%=7.1(1.9)mm < 60%=8.8(2.1)mm), and quadriceps (20%=23.6(14.9)% maximal voluntary isometric contraction < 40%=32.7(11.8)% maximal voluntary isometric contraction < 60%=41.1(13.5)% maximal voluntary isometric contraction) and hamstring (20%=15.5(15.7)% maximal voluntary isometric contraction < 40%=23.0(16.4)% maximal voluntary isometric contraction < 60%=27.6(19.1)% maximal voluntary isometric contraction) activation increased, while quadriceps (20% = 96.7(28.4)ms > 60% 80.2(21.8)ms) and hamstring (20% = 141.5(65.0)ms & 40% = 126.3(68.8)> 60% 107.6(28.4)ms) onset times decreased (P≤0.05). There were no relationships between anterior tibial translation and muscle activation amplitudes (R = .033–.294) or onset times (R = −.031–.374)(P>.09).
Greater axial loads near full knee extension during early weight acceptance result in greater anterior tibial translation, regardless of faster and stronger activation amplitudes. These findings support injury prevention programs aimed to reduce impact forces as they may in turn reduce anterior tibial translation and corresponding ligamentous strain during dynamic activity.
Knee; ACL; Loading Rate
A 69-year-old female patient underwent a standard laparoscopic Nissen fundoplication for repair of a hiatal hernia and correction of reflux. A Harmonic scalpel was used as the only energy source intraoperatively. The operation was uneventful until the middle of the procedure when a significant amount of blood was noted in the left upper quadrant. After aspiration and careful inspection, a 5-cm irregular vertical laceration was found on the posterior and lateral aspect of the spleen, far away from the operative field and any previous instrumentation. Control of bleeding from the spleen was unsuccessful, so a laparoscopic splenectomy was performed, and the procedure was finished without further incident. Histologic examination revealed a normal spleen with no pathologic alterations accounting for the laceration. After comprehensive evaluation of this case to assess a potential cause of the complication, the question arose as to whether the energy produced by the Harmonic scalpel could have caused this splenic laceration.
Laparoscopy; Harmonic scalpel; Complication; Nissen fundoplication; Splenectomy; Energy source
A new regime of pulse parameters in a normal-dispersion fiber laser is identified. Dissipative solitons exist with remarkably large pulse duration and chirp, along with large pulse energy. A low-repetition-rate oscillator that generates pulses with large and linear chirp can replace the standard oscillator, stretcher, pulse-picker, and pre-amplifier in a chirped-pulse fiber amplifier. The theoretical properties of such a giant-chirp oscillator are presented. A fiber laser designed to operate in the new regime generates ~150-ps pulses at 3-MHz repetition rate. Amplification of these pulses to 1-μJ energy with pulse duration as short as 670 fs demonstrates the promise of this new approach.
Light represents a major carrier of information in nature. The molecular machineries translating its electromagnetic energy (photons) into the chemical language of cells transmit vital signals for adjustment of virtually every living organism to its habitat. Fungi react to illumination in various ways, and we found that they initiate considerable adaptations in their metabolic pathways upon growth in light or after perception of a light pulse. Alterations in response to light have predominantly been observed in carotenoid metabolism, polysaccharide and carbohydrate metabolism, fatty acid metabolism, nucleotide and nucleoside metabolism, and in regulation of production of secondary metabolites. Transcription of genes is initiated within minutes, abundance and activity of metabolic enzymes are adjusted, and subsequently, levels of metabolites are altered to cope with the harmful effects of light or to prepare for reproduction, which is dependent on light in many cases. This review aims to give an overview on metabolic pathways impacted by light and to illustrate the physiological significance of light for fungi. We provide a basis for assessment whether a given metabolic pathway might be subject to regulation by light and how these properties can be exploited for improvement of biotechnological processes.
Light response; Metabolic pathways; Strain improvement; Biotechnological processes
We apply a new triaxial antenna for microwave ablation procedures to an ex vivo bovine liver. The antenna consists of a coaxial monopole inserted through a biopsy needle positioned one quarter-wavelength from the antenna base. The insertion needle creates a triaxial structure, which enhances return loss more than 10 dB, maximizing energy transfer to the tissue while minimizing feed cable heating and invasiveness. Numerical electromagnetic and thermal simulations are used to optimize the antenna design and predict heating patterns. Numerical and ex vivo experimental results show that the lesion size depends strongly on ablation time and average input power, but not on peak power. Pulsing algorithms are also explored. We were able to measure a 3.8-cm lesion using 50 W for 7 min, which we believe to be the largest lesion reported thus far using a 17-gauge insertion needle.
Ablation; electromagnetic heating; microwave (MW) ablation; MW heating; RF
Osteoporosis may present a risk factor in achievement of osseointegration because of its impact on bone remodeling properties of skeletal phsiology. The purpose of this study was to evaluate micro-morphological changes in bone around titanium implants exposed to mechanical and electrical-energy in osteoporotic rats.
Fifteen 12-week old sprague-dowley rats were ovariectomized to develop osteoporosis. After 8 weeks of healing period, two titanium implants were bilaterally placed in the proximal metaphyses of tibia. The animals were randomly divided into a control group and biophysically-stimulated two test groups with five animals in each group. In the first test group, a pulsed electromagnetic field (PEMF) stimulation was administrated at a 0.2 mT 4 h/day, whereas the second group received low-magnitude high-frequency mechanical vibration (MECHVIB) at 50 Hz 14 min/day. Following completion of two week treatment period, all animals were sacrificed. Bone sites including implants were sectioned, removed en bloc and analyzed using a microCT unit. Relative bone volume and bone micro-structural parameters were evaluated for 144 μm wide peri-implant volume of interest (VOI).
Mean relative bone volume in the peri-implant VOI around implants PEMF and MECHVIB was significantly higher than of those in control (P < .05). Differences in trabecular-thickness and -separation around implants in all groups were similar (P > .05) while the difference in trabecular-number among test and control groups was significant in all VOIs (P < .05).
Biophysical stimulation remarkably enhances bone volume around titanium implants placed in osteoporotic rats. Low-magnitude high-frequency MECHVIB is more effective than PEMF on bone healing in terms of relative bone volume.
This study was designed to determine the ability of tibial plateau leveling osteotomy (TPLO) to eliminate cranial tibial translation (CTT) through a loaded range of motion. Twenty-four large-breed canine cadaver limbs were compared. Each limb was placed in a custom designed jig at 120° of stifle extension under an axial load of 20% body weight. A force of approximately 10 N/s mimiced the action of the quadriceps muscle and allowed the limb to move from 120° to maximal extension. Positional data were acquired using electromagnetic motion-tracking sensors. Each limb was tested under normal, cranial cruciate ligament (CrCL)-deficient, and TPLO-treated conditions. Cranial tibial translation significantly increased after transection of the CrCL. The TPLO failed to normalize CTT within the CrCL deficient stifle; however, values trended towards intact values throughout the range of motion. The TPLO was more effective at higher angles of flexion. These altered biomechanics may help explain the continued progression of osteoarthritis in TPLO repaired stifles. This loaded model may serve as a method for future evaluation of other surgical techniques.
Total knee arthroplasty (TKA) is often associated with a severe local inflammatory reaction which, unless controlled, leads to persistent pain up to one year after surgery. Standard and accelerated rehabilitation protocols are currently being implemented after TKA, but no consensus exists regarding the long-term effects. Biophysical stimulation with pulsed electromagnetic fields (PEMFs) has been demonstrated to exert an anti-inflammatory effect, to promote early functional recovery and to maintain a positive long-term effect in patients undergoing joint arthroscopy. The aim of this study was to evaluate whether PEMFs can be used to limit the pain and enhance patient recovery after TKA.
A prospective, randomized, controlled study in 30 patients undergoing TKA was conducted. Patients were randomized into experimental PEMFs or a control group. Patients in the experimental group were instructed to use I-ONE stimulator 4hours/day for 60days. Postoperatively, all patients received the same rehabilitation program. Treatment outcome was assessed using the Knee Society Score, SF-36 Health-Survey and VAS. Patients were evaluated pre-operatively and one, two, six and 12 months after TKA. Joint swelling and Non Steroidal Anti Inflammatory Drug (NSAID) consumption were recorded. Comparisons between the two groups were carried out using a two-tail heteroschedastic Student’s t-test. Analysis of variance for each individual subject during the study was performed using ANOVA for multiple comparisons, applied on each group, and a Dunnet post hoc test. A p value < 0.05 was considered statistically significant.
Pre-operatively, no differences were observed between groups in terms of age, sex, weight, height, Knee-Score, VAS, SF-36 and joint swelling, with the exception of the Functional Score. The Knee-Score, SF-36 and VAS demonstrated significantly positive outcomes in the I-ONE stimulated group compared with the controls at follow-ups. In the I-ONE group, NSAID use was reduced and joint swelling resolution was more rapid than in controls. The effect of I-ONE therapy was maintained after use of the device was discontinued.
The results of the study show early functional recovery in the I-ONE group. I-ONE therapy should be considered after TKA to prevent the inflammatory reaction elicited by surgery, for pain relief and to speed functional recovery.
Current Controlled Trials ISRCTN10526056
Total Knee arthroplasty; Pulsed electromagnetic fields; I-ONE therapy; Pain; Inflammation; Functional recovery; Short-term effect; Long-term effect; Knee society score; SF-36 health survey
Pre-clinical studies have shown that treatment by pulsed electromagnetic fields (PEMFs) can limit the catabolic effects of pro-inflammatory cytokines on articular cartilage and favour the anabolic activity of the chondrocytes. Anterior cruciate ligament (ACL) reconstruction is usually performed by arthroscopic procedure that, even if minimally invasive, may elicit an inflammatory joint reaction detrimental to articular cartilage. In this study the effect of I-ONE PEMFs treatment in patients undergoing ACL reconstruction was investigated. The study end-points were (1) evaluation of patients’ functional recovery by International Knee Documentation Committee (IKDC) Form; (2) use of non-steroidal anti-inflammatory drugs (NSAIDs), necessary to control joint pain and inflammation. The study design was prospective, randomized and double blind. Sixty-nine patients were included in the study at baseline. Follow-up visits were scheduled at 30, 60 and 180 days, followed by 2-year follow-up interview. Patients were evaluated by IKDC Form and were asked to report on the use of NSAIDs. Patients were randomized to active or placebo treatments; active device generated a magnetic field of 1.5 mT at 75 Hz. Patients were instructed to use the stimulator (I-ONE) for 4 h per day for 60 days. All patients underwent ACL reconstruction with use of quadruple hamstrings semitendinosus and gracilis technique. At baseline there were no differences in the IKDC scores between the two groups. At follow-up visits the SF-36 Health Survey score showed a statistically significant faster recovery in the group of patients treated with I-ONE stimulator (P < 0.05). NSAIDs use was less frequent among active patients than controls (P < 0.05). Joint swelling resolution and return to normal range of motion occurred faster in the active treated group (P < 0.05) too. The 2-year follow-up did not shown statistically significant difference between the two groups. Furthermore for longitudinal analysis the generalized linear mixed effects model was applied to calculate the group × time interaction coefficient; this interaction showed a significant difference (P < 0.0001) between the active and placebo groups for all investigated variables: SF-36 Health Survey, IKDC Subjective Knee Evaluation and VAS. Twenty-nine patients (15 in the active group; 14 in the placebo group) underwent both ACL reconstruction and meniscectomy; when they were analysed separately the differences in SF-36 Health Survey scores between the two groups were larger then what observed in the whole study group (P < 0.05). The results of this study show that patient’s functional recovery occurs earlier in the active group. No side effects were observed and the treatment was well tolerated. The use of I-ONE should always be considered after ACL reconstruction, particularly in professional athletes, to shorten the recovery time, to limit joint inflammatory reaction and its catabolic effects on articular cartilage and ultimately for joint preservation.
Anterior cruciate ligament; Chondroprotection; Biophysical stimuli; Pulsed electromagnetic fields; Joint preservation
The growing use of transcranial electric and magnetic (EM) brain stimulation in basic research and in clinical applications necessitates a clear understanding of what constitutes the dose of EM stimulation and how it should be reported. The biological effects of EM stimulation are mediated through an electromagnetic field injected (via electric stimulation) or induced (via magnetic stimulation) in the body. Therefore, transcranial EM stimulation dose ought to be defined by all parameters of the stimulation device that affect the electromagnetic field generated in the body, including the stimulation electrode or coil configuration parameters: shape, size, position, and electrical properties, as well as the electrode or coil current (or voltage) waveform parameters: pulse shape, amplitude, width, polarity, and repetition frequency; duration of and interval between bursts or trains of pulses; total number of pulses; and interval between stimulation sessions and total number of sessions. Knowledge of the electromagnetic field generated in the body may not be sufficient but is necessary to understand the biological effects of EM stimulation. We believe that reporting of EM stimulation dose should be guided by the principle of reproducibility: sufficient information about the stimulation parameters should be provided so that the dose can be replicated. This paper provides fundamental definition and principles for reporting of dose that encompass any transcranial EM brain stimulation protocol.
transcranial; stimulation; electric; magnetic; dose
Undergraduate educational settings struggle to provide biologically or medically relevant situations and problems that simultaneously improve students' understanding of physics. Exercises developed in an elective physics course for life sciences or pre–health majors at Portland State University are aimed at teaching fundamental physics concepts within the context of biomedical devices.
Undergraduate educational settings often struggle to provide students with authentic biologically or medically relevant situations and problems that simultaneously improve their understanding of physics. Through exercises and laboratory activities developed in an elective Physics in Biomedicine course for upper-level biology or pre–health majors at Portland State University, we aim to teach fundamental physical concepts, such as light absorption and emission and atomic energy levels, through analysis of biological systems and medical devices. The activities address the properties of electromagnetic waves as they relate to the interaction with biological tissue and make links between physics and biomedical applications such as microscopy or laser eye surgery. We report on the effect that engaging students in tasks with actual medical equipment has had on their conceptual understanding of light and spectroscopy. These initial assessments indicate that students’ understanding improves in some areas as a result of taking the course, but gains are not uniform and are relatively low for other topics. We also find a promising “nonshift” in student attitudes toward learning science as a result of taking the course. A long-term goal of this work is to develop these materials to the extent that they can eventually be imported into an introductory curriculum for life sciences majors.