Antibiotics and Bone Cements: Experimental and Clinical Long-Term Observations

Comparing several antibiotics and different bone cements, the mixture of Palacos® R (polymethylmethacrylate, PMMA) with gentamicin proved to be the most suitable one as far as a high and sustained release of the antibiotic from the artificial resin is concerned. A continuous leaching of gentamicin was observed for more than 5 years. Gentamicin proved to be stable in Palacos R for the whole period of time.

The release of 12 antibiotics from Palaes R was evaluated in vitro. Four other bone cements were included in this ttudy as well, in order to evaluate the leaching of gentamicin from these materials. the combination Gentamicin-Palacos R (GP) showed a 2-3 fold higher and much more prolonged release than did the other mixtures. From this investigation, which also included studies of commercially available antibiotic bone cement mixtures, it is quite obvious that there exist distinct differences in the various bone cements as well as in the various antibiotics as regards their qualification for use in alloarthroplasty.

Pharmacokinetic studies in patients after implantation of GP showed low gentamicin concentrations in serum (on average 1.8μg/ml) and urine. However, in wound exudate, derived directly from the vicinity of the implanted cement, gentamicin concentrations up to 150μg/ml were observed. Also in tissue samples from the vicinity of the implant, high concentrations were measurable for a long period of time (up to 5 1/2 years).     

Penetration of Acrylic Bone Cements into Cancellous Bone

The depth of penetration of five commercial acrylic bone cements into cancellous bone was measured in vitro. Under standard, idealized conditions, cement penetration was found to vary significantly with different cements. Penetration was critically influenced by the coarseness of the cancellous bone and increased directly with the effective volume of the “cells” within the osseous matrix. An inverse correlation was determined between the mean cement viscosity during flow into the bone and final penetration depth. The dough time, set time and working time of each acrylic formulation was found to have no significant effect upon the depth of cement penetration.

It is suggested that in addition to the techniques adopted for introduction of cement to the bone, the selection of the bone cement itself may critically influence the incidence of late loosening following total joint replacement.     

Penetration of Acrylic Bone Cements into Cancellous Bone

The depth of penetration of five commercial acrylic bone cements into cancellous bone was measured in vitro. Under standard, idealized conditions, cement penetration was found to vary significantly with different cements. Penetration was critically influenced by the coarseness of the cancellous bone and increased directly with the effective volume of the “cells” within the osseous matrix. An inverse correlation was determined between the mean cement viscosity during flow into the bone and final penetration depth. The dough time, set time and working time of each acrylic formulation was found to have no significant effect upon the depth of cement penetration.

It is suggested that in addition to the techniques adopted for introduction of cement to the bone, the selection of the bone cement itself may critically influence the incidence of late loosening following total joint replacement.     

Sexually Dimorphic Influence of Neonatal Antibiotics on Bone

The gut microbiome (GM) contributes to host development, metabolism, and disease. Perturbations in GM composition, elicited through chronic administration of oral antibiotics (Abx) or studied using germ‐free environments, alter bone mass, and microarchitecture. However, studies primarily involved chronic Abx exposure to adult mice prior to evaluating the skeletal phenotype. Children are more prone to infection with bacterial pathogens than adults and are thus treated more frequently with broad‐spectrum Abx; consequently, Abx treatment disproportionately occurs during periods of greatest skeletal plasticity to anabolic cues. Because early‐life exposures may exert long‐lasting effects on adult health, we hypothesized that acute Abx administration during a developmentally sensitive period would elicit lasting effects on the skeletal phenotype. To test this hypothesis, neonatal mice were treated with Abx (P7‐P23; oral gavage) or vehicle (water); GM composition, gut physiology, and bone structural and material properties were assessed in adulthood (8 weeks). We found sexually dimorphic effects of neonatal Abx administration on GM composition, gut barrier permeability, and the skeleton, indicating a negative role for neonatal Abx on bone mass and quality. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2122–2129, 2019     

髋关节置换术用丙烯酸骨水泥性能评价的关注点

经查阅髋关节置换术用丙烯酸骨水泥的相关文献、相关技术标准、产品指导原则等,认为对骨水泥的评价主要涉及骨水泥的单体残留、凝固行为、机械性能和生物相容性等产品性能。生产企业应加强骨水泥产品的基础研究能力,制定科学的技术指标和试验方法,以确保产品的安全有效性,同时也可为注册申报提供充分的支持性数据。     

同种异体半脱钙骨修复骨缺损实验研究及临床观察

本文报告我科收治的２７例骨肿瘤及瘤样病变，其骨缺损长度超过５ｃｍ，采用同种异体半脱钙骨移植修复，经２～１３年随访观察，证实其骨诱导能力较强，充填后支架作用好，无排异现象，２７例手术切口均Ⅰ期愈合。并用１ｃｍ×１ｃｍ，２ｃｍ×２ｃｍ，成人皮质骨测量其单位时间内的脱钙程度，为临床选用及制作表面脱钙骨、半脱钙骨、全脱钙骨提供了数据。     

The Penetration of Lincomycin into Normal Human Bone: Determinations of Penetration into Compact Bone, Spongy Bone and Bone Marrow

The penetration of lincomycin into normal bone was studied in 10 patients with fracture of the neck of the femur, a separate determination being made of the lincomycin concentration in serum, bone marrow, spongy bone and compact bone. The concentration of lincomycin in bone marrow was found to be at the same level as that in the serum. The concentration in spongy bone amounted in most cases to 50 to 75 per cent of the concentration in the serum, whereas the concentration in compact bone varied from 0 to 15 per cent of that in the serum.     

活性煅烧骨的实验研究与临床应用

验证煅烧骨是骨形态发生蛋白的理想载体。方法：将骨形态发生蛋白与自制煅烧骨按１：２０的重量比例，组成活性煅烧骨，植入兔尺骨骨缺损处，术后１４，２８，５６，８４天时进行Ｘ线检查，组织学观察，新骨生成量观察及降解率测定，并应用于临床。     

The Modulus of Elasticity and Flexural Strength of Some Acrylic Bone Cements

The modulus of elasticity and flexural strength were measured for three bone cements, CMW Bone Cement, Surgical Simplex, and Palacos R, with various additions and prepared as in actual use. A distinct afterpolymerization was demonstrated in all three brands. The addition of blood lowered the E-modulus whereas radio-opaque media seemed to render them somewhat stiffer. The rupture values demonstrated the inhomogeneity of the final product in all three brands. The possible clinical significance of the findings is discussed.     

Antibiotic Containing Bone Cement Beads in the Treatment of Deep Muscle and Skeletal Infections

Forty-eight cases of chronic osteomyelitis or bacterial arthritis operated on with eradication of infections lesions were randomly treated either by insertion of suction-irrigation drainage or by implantation of gentamicin beads. the average follow-up time was 2 years.

There was no difference in the recurrence rate between the two groups. the gentamicin treated patients were however more easily cared for as the suction-irrigation drainage required constant attention.

Local temporary treatment with gentamicin beads should be used in cases of deep gram—negative muscle and skeletal infections where it would otherwise be necessary to give toxic antibiotics.     

Tibial Implant Fixation Behavior in Total Knee Arthroplasty: A Study With Five Different Bone Cements

BackgroundThe objectives of this study are to (1) evaluate if there is a potential difference in cemented implant fixation strength between tibial components made out of cobalt-chromium (CrCoMo) and of a ceramic zirconium nitride (ZrN) multilayer coating and to (2) test their behavior with 5 different bone cements in a standardized in vitro model for testing of the implant-cement-bone interface conditions. We also analyzed (3) whether initial fixation strength is a function of timing of the cement apposition and component implantation by an early, mid-term, and late usage within the cement-specific processing window.MethodsAn in vitro study using a synthetic polyurethane foam model was performed to investigate the implant fixation strength after cementation of tibial components by a push-out test. A total of 20 groups (n = 5 each) was used: Vega PS CrCoMo tibia and Vega PS ZrN tibia with the bone cements BonOs R, SmartSet HV, Cobalt HV, Palacos R, and Surgical Simplex P, respectively, using mid-term cement apposition. Three different cement apposition times—early, mid-term, and late usage—were tested with a total of 12 groups (n = 5 each) with the bone cements BonOs R and SmartSet HV.ResultsThere was no significant difference in implant-cement-bone fixation strength between CrCoMo and ZrN multilayer-coated Vega tibial trays tested with 5 different commonly used bone cements.ConclusionApposition of bone cements and tibial tray implantation in the early to mid of the cement-specific processing window is beneficial in regard to interface fixation in TKA.     

Bone Vascularization and Bone Healing in the Amputation Stump: An Experimental Study

The osseous healing process of the amputation stump was investigated in adult rabbits. Histological investigation showed that the medullary cavity was closed after 2-3 weeks, chiefly by endosteal callus. After closure of the cavity there was a gradual spongious change in the bone tip and simultaneously the cortex atrophied and the medullary cavity dilated. After amputation on the crus bone rebuilding dominated, whereas after amputation on the femur deterioration of bone was most noticeable. A combination of amputation and medullary plugging caused a change in the course of healing. The medullary cavity did not close until 7-10 weeks after operation and there was distinct periostea] callus formation.

The microangiographic investigation showed a transient hyper-vascularization in the cortex 3-4 weeks after amputation; whereas after simultaneous plugging of the medullary cavity the hypervasculari-zation continued for up to 7 weeks after operation. Following amputation proximally on the crus the arterial supply of the cortex came mainly from the periost, whereas the cortex after distal amputation was vascularized from the medullary cavity. This finding can be due to an interruption of the arterial supply from the nutrient artery associated with proximal amputation, whereas this artery remains intact with amputation distally on the crus.     

Bone Thickening in Osteoarthrosis: Observations of an Osteoarthrosis-Prone Strain of Mouse

Estimations were made of the amount of bone (histologically) and the rate of bone formation (⁸⁵Sr incorporation) in the epiphyses of the knees of osteoarthrosis-prone (STR/ORT) and normal (CBA/ORT) mice. Though the bone was significantly thicker in the STR/ORT mice, this was not the cause of the articular degeneration. Bone sclerosis and cartilage breakdown were chronologically very closely related with perhaps the cartilage changes occurring initially. In male STR/ORT mice bone formation was depressed in the cancellous bone of the epiphyses as, unlike the normal mice, it was at the same level as the compact bone of the femoral shaft. As there was no elevation of the osteoblastic activity in knee joints with developing osteoarthrosis, it would appear that bone sclerosis associated with the disease was due to decreased osteoclasis.     

Soft tissue necrosis following using calcium phosphate cement in calcaneal bone cyst: case report

Calcium phosphate cements have received widespread attention for their possible role as bone-grafting material and bone fillers in skeletal defects. They were evaluated as a biomaterial in many aspects. No serious harmful effects such as foreign body reaction and tissue necrosis against to calcium phosphate cements have been reported yet. They were accepted as highly biocompatible materials. In this paper, we represent a patient who had soft tissue necrosis around lateral malleolar region, following using percutaneous calcium phosphate cement as a filler bone substitute in calcenous bone cyst. The possible mechanisms were discussed.     

Hematologic and Hemostatic Complications Associated with Long-Term Use of Total Artificial Heart: Clinical and Experimental Observations

The two most serious complications associated with long-term use of a total artificial heart (TAH) are thromboembolism and infection. In this article, we review our experience in one patient implanted with a pneumatic TAH for 396 days, and in 24 calves implanted with the same type of device for 70 to 353 (median 150) days. During his survival with the TAH, our patient suffered several thromboembolic episodes despite adequate anti-coagulation with warfarin. Autopsy showed widespread thrombotic lesions, mostly in the brain. Throughout his survival, the patient had markedly elevated plasma beta-thromboglobulin and fibrinopeptide A levels, indicating sustained activation of platelets and the coagulation system secondary to blood contact with the artificial surface. Long-term use of TAH in calves causes significant mechanical hemolytic anemia and a small reduction in the total leukocyte and neutrophil counts. The platelet count normalized to preimplantation levels by 25 to 35 weeks. At autopsy, thrombotic lesions and organ infarction were noted in 13 calves, and major septic complications were documented in 10 animals. Although impressive gains in the clinical and experimental use of TAH were achieved during the last 15 years, thromboembolism and infection remain challenging problems.     

异体骨和异体骨骨水泥在骨骼重建方面的临床观察

目的研究异体骨和异体骨骨水泥重建骨缺损的疗效。方法本组42例，行异体骨植入的20例，异体骨骨水泥(异体骨粒与骨水泥体积比为1：1混合)重建的22例。结果42例患者随访3个月～2．5年，平均1．3a。其中20例用异体骨全部愈合，愈合时间3．5～7个月，平均5．2个月。22例异体骨水泥中有2例骨不连，其余均愈合，愈合率为90．9％，愈合时间为9～12个月，平均10．5个月。结论异体骨和异体骨骨水泥在骨缺损的重建上疗效优良，异体骨应用范围更广，治愈率更高，异体骨骨水泥在治疗良、恶交界性和恶性肿瘤上性能优越，尤其适应于生存时间长的骨肿瘤的保肢术是一种切实可行的方法。     

Protective Effect of Hyaluronidase after Long-Term Aortic Cross-Clamping: Initial Experimental Observations

This work studies the effect of hyaluronidase on myocardium subjected to long-term aortic cross-clamping (three hours) and moderate hypothermia (28°C). Animals receiving hyaluronidase (1,000 U per liter) through the root of the aorta with a procaine-potassium chloride-plasmalyte cardioplegic solution showed better functional, electrical, and morphological response than the untreated animals. These findings, although preliminary, appear to be promising for potential clinical application.     

自身骨泥在长管状骨骨折中的应用与实验研究

探讨长管状骨钢板内固定产生的自身骨泥有无骨诱导活性,能否作为植骨材料及其临床应用。采用22只兔桡骨钻孔采集的骨泥股部肌肉内植入,在二周时五只兔做ECT检测,在一、二、三周取材,做组织形态学观察和碱性磷酸酶(ALP)检测。另5只兔桡骨中段骨折模型一侧自身骨泥植骨、对侧对照,二周做ECT检测。研究结果显示:自身骨泥植入兔肌袋内一周软骨生长,三周网织骨形成;ALP二周水平最高;二周ECF检查肌肉植入区出现放射性浓集,放射性计数明显高于对侧正常肌肉(P<0.05)。骨折模型植骨ECT计数比值明显高于对侧(P<0.05)。52例56处长管状骨钢板内固定自身骨泥植骨取得了良好效果,无一侧骨延迟愈合或骨不连。结果表明长管状骨内固定产生的自身骨泥具有诱导成骨活性,可做为植骨材料,应用于长管状骨骨折钢板内固定一期植骨,可望促进骨折愈合。