In vivo effect of two different pulsed electromagnetic field frequencies on osteoarthritis

Osteoarthritis (OA) is a joint pathology characterized by fibrillation, reduced cartilage thickness and subchondral bone sclerosis. There is evidence that pulsed electromagnetic fields (PEMFs) counteract OA progression, but the effect of two different PEMF frequencies has not yet been shown. The aim of this study was to test the effectiveness of PEMFs at two different frequencies (37 and 75 Hz) in a late OA stage in 21‐month‐old Guinea pigs. After 3 months of 6 h/day PEMF stimulation, histological and histomorphometric analyses of the knees were performed. At both frequencies, PEMFs significantly reduced histological cartilage score, fibrillation index (FI), subchondral bone thickness (SBT) and trabecular number (Tb.N) and increased trabecular thickness (Tb.Th) and separation (Tb.Sp) in comparison to the not treated SHAM group. However, PEMFs at 75 Hz produced significantly more beneficial effects on the histological score and FI than 37 Hz PEMFs. At 75 Hz, PEMFs counteracted cartilage thinning as demonstrated by a significantly higher cartilage thickness values than either those of the SHAM or 37 Hz PEMF‐treated groups. Although in severe OA both PEMF frequencies were able to limit its progression, 75 Hz PEMF stimulation achieved the better results. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:677–685, 2014.     

脉冲电磁场对接骨板性骨质疏松的影响

我们对钢板固定家兔胫骨用ＰＥＭＦｓ进行治疗 ,观察固定骨段的骨孔隙率 ,骨矿含量和矿化沉积率的变化 ,以期为临床应用ＰＥＭＦｓ防治接骨板性骨质疏松提供依据。1　材料与方法1 1　动物　健康成年大耳白家兔 18只 ,雌雄不限 ,体重在 2 5～ 3 0ｋｇ(河南医科大学实验动物中心提供 )。标准全价营养饲料分笼喂养。1 2　接骨板　采用天津产 4孔 316Ｌ不锈钢掌骨接骨板。1 3　仪器　ＴＦ ＶＩ型中医多功能治疗仪由郑州市颈肩腰腿痛医院研究所提供 (专利号 :992 385 4 2 3)。1 4　分组与处理　动物随机分为Ａ、Ｂ、Ｃ三组 ,每组各 6只。Ａ组为…     

低频脉冲电磁场对去势骨质疏松大鼠腰椎骨形态计量学的影响

目的观察低频脉冲电磁场(pulsed electromagnetic fields,PEMFs)对去势骨质疏松(osteoporosis,OP)大鼠腰椎骨组织形态计量学的影响,探讨PEMFs治疗OP的作用机制。方法将66只3月龄雌性SD大鼠随机分为假手术组(A组,n=12)、PEMFs实验组(B组,n=12)、雌激素对照组(C组,n=12)、卵巢切除对照组(D组,n=30)。A组大鼠仅切除卵巢周围部分脂肪组织,不切除卵巢;其余各组大鼠均切除双侧卵巢,制备去势OP大鼠模型。术后12周,B组采用低频PEMFs(8 Hz、3.8 mT、40 min/d)干预治疗30 d;C组采用倍美力0.065 mg/(kg.d)灌胃30 d;A、D组正常饲养。观察各组大鼠一般情况,术后12周检测血清雌二醇水平;干预治疗30 d后处死大鼠,取L4椎体作组织学切片,行静态骨形态计量学分析。结果术后D组大鼠毛发逐渐稀疏,活动迟缓,精神不振,反应较迟钝;A、B、C组大鼠毛发均光洁,精神及活动正常。术后12周,A组和D组大鼠血清雌二醇水平分别为(54.93±23.52)pg/mL和(31.99±23.45)pg/mL,比较差异有统计学意义(t=2.345,P=0.029)。干预治疗30 d后HE染色观察示,D组骨质变薄,骨髓扩大,骨小梁分布稀疏并变细,见断裂现象;A、B、C组骨小梁粗细一致,分布均匀,无断裂现象。B组大鼠L4椎体骨小梁面积百分比显著高于D组(P<0.05),也高于A、C组,但差异无统计学意义(P>0.05);骨小梁厚度显著高于D组(P<0.05),低于A、C组,但差异无统计学意义(P>0.05);骨小梁数量显著低于D组(P<0.05),高于A、C组,但差异无统计学意义(P>0.05);骨小梁分离度高于D组,低于A、C组,差异均无统计学意义(P>0.05)。结论 8 Hz、3.8 mT的PEMFs干预30 d可有效改善去势OP大鼠骨显微结构,增加骨小梁面积百分比、骨小梁厚度,降低骨小梁数量,对大鼠OP有良好的防治作用。     

Cartilage repair with osteochondral autografts in sheep: Effect of biophysical stimulation with pulsed electromagnetic fields

The effect of pulsed electromagnetic fields (PEMFs) on the integration of osteochondral autografts was evaluated in sheep. After osteochondral grafts were performed, the animals were treated with PEMFs for 6 h/day or sham‐treated. Six animals were sacrificed at 1 month. Fourteen animals were treated for 2 months and sacrificed at 6 months. At 1 month, the osteogenic activity at the transplant–host subchondral bone interface was increased in PEMF‐treated animals compared to controls. Articular cartilage was healthy in controls and stimulated animals. At 6 months, complete resorption was observed in four control grafts only. Cyst‐like resorption areas were more frequent within the graft of sham‐treated animals versus PEMF‐treated. The average volume of the cysts was not significantly different between the two groups; nevertheless, analysis of the variance of the volumes demonstrated a significant difference. The histological score showed no significant differences between controls and stimulated animals, but the percentage of surface covered by fibrous tissue was higher in the control group than in the stimulated one. Interleukin‐1 and tumor necrosis factor‐α concentration in the synovial fluid was significantly lower, and transforming growth factor‐β1 was significantly higher, in PEMF‐treated animals compared to controls. One month after osteochondral graft implantation, we observed larger bone formation in PEMF‐treated grafts which favors early graft stabilization. In the long term, PEMF exposure limited the bone resorption in subchondral bone; furthermore, the cytokine profile in the synovial fluid was indicative of a more favorable articular environment for the graft. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:631–642, 2008     

Triple arthrodesis with an external rail fixator: A review of 8 cases

The results of 8 patients who underwent triple arthrodesis with a rail external fixator were reviewed retrospectively. The frame construct allowed immediate axial loading and unrestricted ankle joint mobilization. Assistive ambulatory equipment was not required postoperatively. Periodic adjustment to compression was performed weekly until evidence of radiographic consolidation. The mean duration of frame application was 11.5 weeks. Follow-up averaged 15.9 months. Fusion occurred in all joints. One superficial pin-tract infection developed that resolved with oral antibiotics. The results of this study indicate that the rail frame system provides a viable fixation alternative for triple arthrodesis and warrants further investigation.     

Role of pulsed electromagnetic fields after joint replacements

Although the rate of patients reporting satisfaction is generally high after joint replacement surgery, up to 23% after total hip replacement and 34% after total knee arthroplasty of treated subjects report discomfort or pain 1 year after surgery. Moreover, chronic or subacute inflammation is reported in some cases even a long time after surgery. Another open and debated issue in prosthetic surgery is implant survivorship, especially when related to good prosthesis bone ingrowth. Pulsed Electro Magnetic Fields(PEMFs) treatment, although initially recommended after total joint replacement to promote bone ingrowth and to reduce inflammation and pain, is not currently part of usual clinical practice. The purpose of this review was to analyze existing literature on PEMFs effects in joint replacement surgery and to report results of clinical studies and current indications. We selected all currently available prospective studies or RCT on the use of PEMFs in total joint replacement with the purpose of investigating effects of PEMFs on recovery, pain relief and patients' satisfaction following hip, knee or shoulder arthroplasty. All the studies analyzed reported no adverse effects, and good patient compliance to the treatment. The available literature shows that early control of joint inflammation process in the first days after surgery through the use of PEMFs should be considered an effective completion of the surgical procedure to improve the patient's functional recovery.     

The effects of pulsed electromagnetic fields on blood vessel growth in the rabbit ear chamber.

A double-blind, controlled trial of the effects of pulsed electromagnetic fields on capillary growth in the rabbit ear chamber in adult New Zealand white rabbits has been performed. Three waveforms have been investigated. The first, a pulse burst waveform, produced a significant increase in the rate of growth of the vascular tissue within the chamber, but had no effect on macroscopic tissue maturation. The second and third, two different single pulse waveforms, had, in contrast, no significant effect on the rate of vascular growth and only an effect on vessel characteristics, with increased maturation of vessels using the second waveform. It is concluded that some of the observed effects of pulsed electromagnetic fields on tissue healing may be mediated through a primary effect on vascular growth.     

The effect of pulsed electromagnetic fields on bone cell metabolism and calvaria resorption in vitro,and on calcium metabolism in the live rat

Summary The effects of three pulsed electromagnetic fields were investigated on bone cells and calvaria in culture, and on calcium metabolism in the live rat. No significant effect was seen on: 1) the proliferation of calvaria cells in culture; 2) alkaline phosphatase level, lactic acid release and collagen synthesis by confluent calvaria cells, with the exception of one pulse which produced a small increase in the latter when expressed as DNA; 3) resorption of calvaria in culture; 4) intestinal absorption, urinary excretion and net balance of calcium, bone formation and bone resorption in the live rat.on leave from Department of Pharmacology, School of Dentistry, Tokyo Medical and Dental University, Tokyo, Japan     

Modulation of bone loss during disuse by pulsed electromagnetic fields

The effect of pulsed electromagnetic fields (PEMFs) on bone loss associated with disuse was investigated by applying 1.5 Hz repetitions of 30 ms bursts of asymmetric pulses, varying from +2.5 to -135 mV, to bones deprived of their normal functional loading. The proximal portion of one fibula in each of a group of ovariectomised adult female beagle dogs was isolated from functional loading in vivo by proximal and distal osteotomies. Comparison of these prepared bones with their intact contralateral controls after 12 weeks, showed a 23% reduction in cross-sectional area. In similarly prepared bones exposed to PEMFs for 1 h per day, 5 days per week, this bone loss was substantially and significantly reduced to 9% (p = 0.029). There was no evidence of any new bone formation on the periosteal surface of prepared fibulae in treated or untreated situations. PEMF treatment was not associated with any significant change in number of osteons per mm2 formed within the cortex of the bones, their radial closure rate, or their degree of closure. The modulation in loss of bone area associated with exposure to PEMFs can, therefore, be inferred to be due to a reduction in resorption on the bone surface.     

脉冲电磁场对MC3T3-E1细胞增殖与分化的影响

目的研究不同强度50Hz脉冲电磁场(Pulse electromagnetic fields,PEMFs)对小鼠成骨细胞系MC3T3-E1增殖与分化的影响。方法 MC3T3-E1传代培养后分成七组,分别采用0.0 m T、0.6 m T、1.2 m T、1.8 m T、2.4 m T、3.0 m T和3.6 m T 50 Hz脉冲电磁场处理,90 min/d。MTT法检测细胞增殖情况,成骨性分化检测处理3 d、6 d、9 d、12 d后ALP活性和首次处理12 h后BMP-2、Runx-2、OPG基因表达情况。结果 6种强度的脉冲电磁场均促进细胞增殖,其中0.6 m T的促增殖效应最强(P<0.01)。在成骨性诱导培养条件下,细胞内ALP活性随电磁场处理时间的延长而逐渐增加,第9 d达到峰值,之后开始回落。0.6 m T、3.0 m T和3.6 m T均能提高ALP活性,其中0.6 m T始终处于最高水平(P<0.01)。三种基因的表达水平在首次处理12 h,在0.6 m T、1.2 m T、3 m T和3.6 m T组均显著提高,但仍然是0.6 m T的增强效应最为明显。结论 0.6 m T 50 Hz脉冲电磁场具有最佳的促进MC3T3-E1细胞增殖和成骨性分化活性,这可能为采用脉冲电磁场治疗骨质疏松症提供了理想的治疗参数。     

脉冲电磁场促进人骨髓间充质干细胞成骨的研究

目的 :观察脉冲电磁场 (PEMFs)对人骨髓间充质干细胞 (hMSCs)成骨能力的影响。方法 :hMSCs受频率 12Hz、场强 1.1mT的PEMFs刺激 8h/d ,检测细胞增殖、细胞周期 ,观察细胞超微结构、骨钙素、Ⅰ型胶原免疫组化染色 ,碱性磷酸酶 (ALP)活性、核固红钙染色。结果 :脉冲电磁场作用后的细胞增殖能力提高 ,细胞形态发生变化 ,透射电镜观察提示细胞成熟 ,核固红钙染色、骨钙素、Ⅰ型胶原免疫组化染色均阳性 ,ALP活性增高。结论 :hMSCs经合理的PEMFs体外刺激后 ,细胞增殖加速 ,符合成骨细胞的形态特征和生物学特性。     

Low dose short duration pulsed electromagnetic field effects on cultured human chondrocytes: An experimental study

Background:

Pulsed electromagnetic field (PEMF) is used to treat bone and joint disorders for over 30 years. Recent studies demonstrate a significant effect of PEMF on bone and cartilage proliferation, differentiation, synthesis of extracellular matrix (ECM) and production of growth factors. The aim of this study is to assess if PEMF of low frequency, ultralow field strength and short time exposure have beneficial effects on in-vitro cultured human chondrocytes.

Materials and Methods:

Primary human chondrocytes cultures were established using articular cartilage obtained from knee joint during joint replacement surgery. Post characterization, the cells were exposed to PEMF at frequencies ranging from 0.1 to 10 Hz and field intensities ranging from 0.65 to 1.95 μT for 60 min/day for 3 consecutive days to analyze the viability, ECM component synthesis, proliferation and morphology related changes post exposure. Association between exposure doses and cellular effects were analyzed with paired''t’ test.

Results:

In-vitro PEMF exposure of 0.1 Hz frequency, 1.95 μT and duration of 60 min/day for 3 consecutive days produced the most favorable response on chondrocytes viability (P < 0.001), ECM component production (P < 0.001) and multiplication. Exposure of identical chondrocyte cultures to PEMFs of 0.65 μT field intensity at 1 Hz frequency resulted in less significant response. Exposure to 1.3 μT PEMFs at 10 Hz frequency does not show any significant effects in different analytical parameters.

Conclusions:

Short duration PEMF exposure may represent a new therapy for patients with Osteoarthritis (OA).     

The effect of pulsed electromagnetic fields on the osteointegration of hydroxyapatite implants in cancellous bone: a morphologic and microstructural in vivo study.

Effects of pulsed electromagnetic fields (PEMFs, 75 Hz. 1.6 mT) were investigated in 12 rabbits after placing hydroxyapatite (HA) implants in their femoral condyles. Six animals were stimulated with PEMFs for three consecutive weeks, 6 h/day, while the remaining animals were sham-treated (Control Group). Rabbits were sacrificed at 3 and 6 weeks (after a 3-week non-stimulation period) for histomorphometric analysis and microhardness testing (at 200, 500, 1,000, 2,000 microm from the implant) around the implants. Histomorphometric analysis did not highlight any significant changes. On the contrary, there were statistically significant differences between the effects produced by PEMFs and Control Groups (F = 149.70, p < 0.0005) on the Affinity Index results, as well as by the experimental time of 6 and 3 weeks (F = 17.12, p = 0.001) on the same results. In PEMF-stimulated animals the microhardness (HV) values measured in trabecular bone at a distance of 200 and 500 microm from the implants, were significantly higher with respect to controls. At 6 weeks, HV values at the bone-implant interface in PEMF-stimulated animals were not significantly different with respect to normal bone, while they remained significantly lower in control animals. Both morphological and structural results demonstrated a positive therapeutic effect of PEMFs in accelerating HA osteointegration in trabecular bone.     

BEMF对去卵巢骨质疏松大鼠骨组织bFGF表达的影响及意义

目的 观察BEMF对去卵巢骨质疏松大鼠骨组织bFGF蛋白表达的影响,探讨BEMF治疗骨质疏松的机理.方法 6月龄雌性未孕Wistar大鼠40只,按体质量随机分为模型组（OVX）、假手术组（Sham）、仿生脉冲电磁场治疗组（BEMF＋OVX,EM）、雌激素治疗组（Estrogen＋OVX,E）.OVX、EM、E组行双侧卵巢切除术,Sham组行假手术.术后第9 W开始治疗：E组行苯甲酸雌二醇肌肉注射,0.5mg/kg,1次/2 W.EM组大鼠暴露于仿生脉冲电磁场治疗,1 h/1次/d,OVX、Sham组不予以任何处理,作为对照组.治疗10 W后处死各组实验动物,测量腰椎骨密度、椎体的最大载荷、扫描电镜观察椎体骨结构的变化.采用免疫组化检测椎体骨组织中bFGF蛋白表达情况并以图像分析进行组间比较.结果 治疗10 W后EM组大鼠骨密度、椎体的最大载荷较OVX组显著性增高（P＜0.05）,骨结构明显改善.bFGF的表达主要位于成骨细胞、骨细胞,EM组椎体骨组织中bFGF表达显著性高于OVX组（P＜0.01）.结论 提高骨组织中bFGF的表达是BEMF治疗骨质疏松的重要机理之一.     

低强度脉冲电磁场对去卵巢大鼠不同部位骨密度的影响

目的 探讨低强度脉冲电磁场(PEMFs)对去势雌性大鼠不同部位骨密度的影响.方法 30只10月龄雌性SD大鼠随机分为3组:一组去势造模(造模组),另一组行假手术(空白组),第三组去势造模后暴露于50 Hz、0.16 mT的磁场环境下60 min/d,共90天(磁疗组).实验期间动态观察大鼠全身及颅骨骨密度,期满处死后测定血清雌二醇水平及骨密度.结果 ①空白组雌激素水平和子宫系数均显著高于其他两组(P<0.01);②至60天时,空白组、磁疗组的颅骨骨密度显著高于造模组(P<0.05),全身骨密度在90天时才出现统计学意义(P<0.05);③与空白组和磁疗组相比,造模组椎体骨密度(P<0.01)比腰椎骨密度(P<0.05)差异更显著,磁疗组股骨骨密度虽较造模组有所上升但差异未达到统计学意义.结论 全身骨密度与颅骨骨密度结合可有效评估大鼠活体骨密度动态变化;PEMFs对因去势造成的骨密度下降有明显抑制作用,且对不同部位骨密度影响程度不同;采用去椎弓的单一椎体为骨密度衡量点能更为敏感的反映治疗效果.     

BEMF对卵巢切除骨质疏松大鼠治疗作用的骨形态计量学研究

目的观察BEMF对OVX—OP大鼠骨形态计量学指标的影响，探讨BEMF对卵巢切除致骨质疏松大鼠的治疗作用及机制。方法6个月龄雌性未孕Wistar大鼠40只，按体质量随机分为卵巢切除组（OVX）、假手术组（Sham）、仿生电磁场治疗组（EM）、雌激素治疗组（E）。术后8周，E组苯甲酸雌二醇肌肉注射，0．5mg／kg，1次，2周。EM组大鼠暴露于仿生电磁场治疗，1h·次^-1·d^-1，OVX、Sham组不予以任何处理，作为对照组。治疗10周后处死各组大鼠，取左侧胫骨进行骨形态计量学测定。结果治疗10周后，EM组大鼠％Tb．Ar、Tb．Th、Tb．N较OVX组显著增加（P〈0．01），Tb．sp显著降低（P〈0．01），与E组变化相似。E组、EM组大鼠成骨细胞数（％L．Pm）低于OVX组（P〈0．01）；EM组、E组仍高于Sham组（P〈0．01）；EM组高于E组（P〈0．01）。E组、EM组破骨细胞数（N．Oc）低于OVX组（P〈0．01）；EM组、E组仍高于Sham组，（P〈0．01）；EM组高于E组，差异非常显著（P〈0．01）。结论BEMF具有增加骨量、改善骨结构的作用；与雌激素的治疗作用存在不同机制。     

Four-corner arthrodesis: influence of the position of the lunate on postoperative wrist motion: a cadaveric study

PURPOSE: Evaluate the influence of the position of the lunate on postoperative wrist motion in four-corner arthrodesis. METHODS: Six upper cadaveric limbs were evaluated, comparing the total arc of motion in each wrist after simulating four-corner arthrodesis. The lunate was fixed in 3 different positions: neutral (0 degrees ), extended (30 degrees ), and flexed (20 degrees ). Statistical analyses (ANOVA and Bonferroni tests) were carried out to establish the significance of differences in articular motion in these 3 positions. RESULTS: Significant statistical differences were observed in full wrist extension. No significant differences, however, were found in flexion-extension total arc of motion, radial deviation, or ulnar deviation. CONCLUSIONS: According to our results in this cadaveric model, the position of the lunate affects postoperative wrist flexion and extension after four-corner arthrodesis. The flexed lunate position increases postoperative wrist extension and restrains wrist flexion. Inversely, the extended lunate position improves articular flexion and limits extension. Total arc of motion of the fused wrist does not vary in the 3 lunate positions.     

不同频率脉冲电磁场对骨保护素基因敲除小鼠骨代谢指标影响

目的采用不同频率的脉冲电磁场干预骨保护素基因敲除小鼠骨质疏松模型,探讨脉冲电磁 场治疗骨质疏松的最适治疗频率。方法8周龄雌雄各半骨保护素基因敲除小鼠30只,随机分为 A、B、C 3组,每组10只,粤组为空白对照组,不进行干预;B组小鼠每天在强度为4皂栽,频率为8 HZ 的磁场中照射治疗20 min,共30 d;C组小鼠每天在强度为4 mT,频率为32 HZ的磁场中照射治疗20 min,共30凿。各组小鼠在治疗前及治疗30d后用酶联免疫法（ELISA )法检测抗酒石酸酸性磷酸酶 缘遭及血清骨钙素值。结果8HZ、32HZ两治疗组在治疗后抗酒石酸酸性磷酸酶5遭,血清骨钙素含 量与A对照组之间比较差异有统计学意义（P <0.05 ), 8 HZ、32 HZ两治疗组之间治疗前与治疗后所 测三种指标比较差异无统计学意义（P >0.05 )。结论脉冲电磁场对骨保护素基因敲除小鼠骨质疏 松有肯定治疗效果,应用频率为8-32 HZ的磁场治疗能产生相同的治疗效果。