Antibiotic-free antimicrobial poly (methyl methacrylate) bone cements: A state-of-the-art review

Prosthetic joint infection (PJI) is the most serious complication following total joint arthroplasty, this being because it is associated with, among other things, high morbidity and low quality of life, is difficult to prevent, and is very challenging to treat/manage. The many shortcomings of antibiotic-loaded poly (methyl methacrylate) (PMMA) bone cement (ALBC) as an agent for preventing and treating/ managing PJI are well-known. One is that microorganisms responsible for most PJI cases, such as methicillin-resistant S. aureus, have developed or are developing resistance to gentamicin sulfate, which is the antibiotic in the vast majority of approved ALBC brands. This has led to many research efforts to develop cements that do not contain gentamicin (or, for that matter, any antibiotic) but demonstrate excellent antimicrobial efficacy. There is a sizeable body of literature on these so-called “antibiotic-free antimicrobial” PMMA bone cements (AFAMBCs). The present work is a comprehensive and critical review of this body. In addition to summaries of key trends in results of characterization studies of AFAMBCs, the attractive features and shortcomings of the literature are highlighted. Shortcomings provide motivation for future work, with some ideas being formulation of a new generation of AFAMBCs by, example, adding a nanostructured material and/or an extract from a natural product to the powder and/or liquid of the basis cement, respectively.     

Characterization of Bone Cements

Thirty-seven patients with fractures of the thoracic and lumbar spine treated with Harrington instrumentation were reviewed. Twenty-seven patients with a follow-up time of more than 2 years were summoned for a clinical and radiographic examination. This report presents the results related to reduction, stabilization, return of neural function, spinal posture and mobility, and residual disability. It is concluded that Harrington instrumentation can be performed without a substantial number of complications. Its major advantages are early mobilization and ambulation. The operative technique is discussed with special reference to the preservation of the normal configuration of the back. The value of computerized tomography in the preoperative assessment is stressed.     

On Injuries to the Acromio-Clavicular Joint: Treatment and Results

A study was made of bone ingrowth into fiber metal composite prostheses used to replace large segments of the femur in baboons. Bone grafts of two different types were used to cover the segment: chips of bone with large particle size and ground bone with a smaller particle size. The prosthetic segment was bridged by bone at 3 and 6 months in all cases irrespective of the structure of the transplant. In animals sacrificed at 6 months bone ingrowth occurred, with a marked difference between specimens with the two different grafts. In the ground bone specimens ingrowth occurred over the total surface area, and bone penetrated deep into the composite. With the chip grafts ingrowth was more irregular occurring only in some areas and it was always superficial. The difference is believed to be due to the improved contact between the fiber metal surface and the transplant. The lesser bulk of the ground transplant is advantageous when the soft tissue cover of the bone is thin.     

Segmental Replacement of the Femur in Baboons with Fiber Metal Implants and Autologous Bone Grafts of Different Particle Size

A study was made of bone ingrowth into fiber metal composite prostheses used to replace large segments of the femur in baboons. Bone grafts of two different types were used to cover the segment: chips of bone with large particle size and ground bone with a smaller particle size. The prosthetic segment was bridged by bone at 3 and 6 months in all cases irrespective of the structure of the transplant. In animals sacrificed at 6 months bone ingrowth occurred, with a marked difference between specimens with the two different grafts. In the ground bone specimens ingrowth occurred over the total surface area, and bone penetrated deep into the composite. With the chip grafts ingrowth was more irregular occurring only in some areas and it was always superficial. The difference is believed to be due to the improved contact between the fiber metal surface and the transplant. The lesser bulk of the ground transplant is advantageous when the soft tissue cover of the bone is thin.     

高粘度骨水泥与低粘度骨水泥椎体成形术治疗骨质疏松性椎体压缩性骨折的疗效比较

目的 比较在椎体成形术中，高粘度骨水泥和低粘度骨水泥治疗骨质疏松性椎体压缩性骨折的临床疗效差异。方法 回顾性分析83例骨质疏松性椎体压缩性骨折患者，接受椎体成形术后的病例资料。其中采用低粘度骨水泥椎体成形术患者43例；采用高粘度骨水泥椎体成形术患者40例。记录单个椎体手术时间、骨水泥渗漏发生率，术后并发症发生率。利用视觉模拟评分及功能障碍指数评分对两组进行术前及术后一天、术后三个月疼痛及功能评价。通过X线片对术前、术后椎体各部进行测量，统计椎体高度变化。结果 83例患者均得到随访，通过对两组的各项指标比较，在术前视觉模拟评分和术前骨折压缩率上无明显统计学差异。在手术时间上高粘度组较低粘度骨水泥组明显缩短（t=22.32，P=0.000）。高粘度骨水泥组和低粘度骨水泥组的术后一日、术后三个月视觉模拟评分、功能障碍指数评分较术前明显降低，组内差异有高度显著性（P=0.000），组间无明显差异。高粘度组骨水泥渗漏率较低粘度骨水泥组明显降低，差异有统计学意义（P=0.0494）。椎体成形术后高粘度骨水泥组椎体高度恢复优于低粘度骨水泥组，差异有显著统计学意义（P=0.000）。结论 椎体成形术中使用不同类型的骨水泥都能有效的缓解病人疼痛，改善生活质量。与低粘度骨水泥相比，高粘度骨水泥有着较低的骨水泥渗漏率，同时缩短了手术时间和减少放射性的暴露。高粘度骨水泥在治疗骨质疏松性椎体压缩性骨折方面有一定的优势。     

Viability and Osteogenicity of Bone Graft Coated with Methylmethacrylate Cement

The idea of utilizing bone grafts during hip arthroplasty has been discussed in the literature and clinical successes have been indicated. These communications, however, did not relate to long-term results. Thus, to date, we still lack sufficient understanding as to the fate of bone grafts when they are coated with methyl-methacrylate. In order to elucidate the above issue further an experimental study has recently been initiated in an attempt to provide answers to the following questions: a) do bone grafts remain viable when they are held in place with methyl-methacrylate bone cement? and b) do such grafts retain their osteogenic potential? In the present study osteotomies were made in the femora of dogs and cortico-cancellous strips of autogenous bone were placed around the osteotomy site. The grafts were then surrounded by polymethylmethacrylate bone cement. Mechanical examinations and morphological studies, performed 3, 6 and 10 months following surgery, revealed the elaboration of fibro-osseous union. Our present findings tend to indicate that bone grafts, even if they are covered with methylmethacrylate bone cement, still retain their viability as well as their osteogenic potential.     

Pelvic ramus fractures in the elderly

Background Whilst it is well known that fractures of the pelvic rami in the elderly are frequently associated with posterior ring injuries, the extent of this second injury is less well known. We evaluated this question by MRI scanning a group of elderly patients presenting at our unit with pelvic rami fractures.

Patients and methods We investigated 50 consecutive elderly patients (45 women) with fractures of the pelvic rami using an MRI scan of the pelvis in order to assess the competency of the pelvic ring.

Results On MRI, 45 (95% CI 42–48) patients had a sacral fracture. At 5-month follow-up, 39 (of 41 reviewed) still complained of posterior sacral tenderness.

Interpretation Pelvic rami fractures in the elderly are nearly always associated with posterior ring injuries. This probably explains why these patients take longer to rehabilitate than might be expected if only the anterior injury is considered, and it also explains why they experience long-term back pain.     

椎体成形术中高黏度骨水泥渗漏分析

目的了解高黏度骨水泥在椎体成形术中的渗漏率、渗漏部位及其临床疗效等相关问题。方法回顾性分析本院自2013-06—2014-09行高黏度骨水泥经皮椎体成形术42例的影像资料及临床病例,分析研究手术前后腰背部疼痛VAS评分,骨水泥渗漏部位及相关并发症等。结果患者术后24 h疼痛均明显缓解,视觉疼痛模拟评分(VAS)明显改善(P0.05),10例13个椎体(22.81%)出现骨水泥渗漏,椎体周围渗漏发生率(46.15%)最高,均未出现明显临床症状及体征。结论高黏度骨水泥能确切改善患者疼痛症状,渗漏率相对较低,且多无明显临床症状,适合临床应用。     

腰椎滑脱症后路自体、同种异体混合骨泥植骨效果分析

[目的]选用自体、同种异体冻干骨泥混合,作为腰椎滑脱症(lumbar spondylolisthesis,LS)椎体间植骨材料。并进行随访,以探讨其骨性融合效果。[方法]随机选取LS病例86例,全部病例按照植骨材料的不同分为自体骨泥组、混合骨泥组。采用腰椎后路椎体间植骨融合术(posterior lumbar interbody fusion,PLIF)。随访时间2年2个月~4年3个月,平均2年5个月。在术前、术后第3个月复查时统计患者VAS评分、Oswestry功能障碍指数(ODI,下同),同时参照JOA腰椎部分评分标准行JOA评分。同时在术后第3、12、24个月复查腰椎X线片、腰椎CT,参考Suk法进行椎体融合评价。[结果]自体骨泥组和混合骨泥组的手术时间和术中出血量没有显著差异。JOA评分示自体骨泥组的优良率达96.77%(30/31例),混合骨泥组优良率达93.02%(40/43例)。术后3个月腰椎X线片示腰椎滑脱解剖复位率为83.78%(62/74例)。83.87%(26/29例)的自体骨泥组患者和79.07%(34/43例)的混合骨泥组患者在12个月内达到骨性愈合标准。两组骨性融合效果没有显著差异。[结论]腰椎滑脱症后路自体、同种异体混合骨泥植骨可以达到较高的融合效果,临床应用效果肯定。     

不同黏度骨水泥椎体成形术治疗骨质疏松性椎体压缩性骨折

目的 比较采用高黏度骨水泥和低黏度骨水泥椎体成形术治疗骨质疏松性椎体压缩性骨折的临床疗效差异.方法 回顾性分析2013年9月至2014年11月我科治疗的83例骨质疏松性椎体压缩性骨折病人的病例资料.根据手术所用不同黏度骨水泥分组:采用低黏度骨水泥椎体成形术治疗的病人43例(低黏度组);采用高黏度骨水泥椎体成形术治疗的病人40例(高黏度组).记录单个椎体手术时间、骨水泥渗漏发生率,术后并发症发生率.采用疼痛视觉模拟量表(visual analogue scale,VAS)及Oswestry功能障碍指数(Oswestry disability index,ODI)对两组进行术前及术后1 d、术后3个月疼痛及功能进行评价.通过X线检查对术前、术后椎体各部进行测量,统计椎体高度变化.结果 83例病人术后均得到3个月随访.两组术前VAS评分和骨折压缩率上无差异.高黏度组的手术时间较低黏度组明显缩短(t=22.32,P=0.000).术后1 d、术后3个月,两组组内VAS评分、ODI较术前明显降低(均P=0.000),但术后组间比较无明显差异(均P>0.05).高黏度组骨水泥渗漏率较低黏度组低,差异有统计学意义(P=0.0494).椎体成形术后高黏度组椎体高度恢复优于低黏度组,差异有统计学意义(P=0.000).结论 椎体成形术中使用不同类型的骨水泥均能有效地缓解病人疼痛,改善生活质量.与低黏度骨水泥相比,高黏度骨水泥有着较低的骨水泥渗漏率,同时缩短了手术时间和降低了术中放射性的暴露.     

Microencapsulation of rifampicin: A technique to preserve the mechanical properties of bone cement

Two‐stage exchange with antibiotic‐loaded bone cement spacers remains the gold standard for chronic periprosthetic joint infection (PJI). Rifampicin is highly efficient on stationary‐phase staphylococci in biofilm; however, its addition to PMMA to manufacture spacers prevents polymerization and reduces mechanical properties. Isolation of rifampicin during polymerization by microencapsulation could allow manufacturing rifampicin‐loaded bone cement maintaining elution and mechanical properties. Microcapsules of rifampicin with alginate, polyhydroxybutyratehydroxyvalerate (PHBV), ethylcellulose and stearic acid (SA) were synthesized. Alginate and PHBV microcapsules were added to bone cement and elution, compression, bending, hardness, setting time and microbiological tests were performed. Repeated measures ANOVA and Bonferroni post‐hoc test were performed, considering a p < 0.05 as statistical significance. Bone cement specimens containing alginate microcapsules eluted more rifampicin than PHBV microcapsules or non‐encapsulated rifampicin over time (p < 0.012). Microencapsulation of rifampicin allowed PMMA to preserve mechanical properties in compression and bending tests. Cement with alginate microcapsules showed similar behavior in hardness tests to control cement over the study period (73 ± 1.68H_D). PMMA with alginate microcapsules exhibited the largest zones of inhibition in microbiological tests. Statistically significant differences in mean diameters of zones of inhibition between PMMA loaded with alginate‐rifampicin (p = 0.0001) and alginate‐PHBV microcapsules (p = 0.0001) were detected. Rifampicin microencapsulation with alginate is the best choice to introduce rifampicin in PMMA preserving mechanical properties, setting time, elution, and antimicrobial properties. The main applicability of this study is the opportunity for obtaining rifampicin‐loaded PMMA by microencapsulation of rifampicin in alginate microparticles, achieving high doses of rifampicin in infected tissues, increasing the successful of PJI treatment. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:459–466, 2018.

     

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。     

Finite element simulation of cement‐bone interface micromechanics: A comparison to experimental results

Recently, experiments were performed to determine the micromechanical behavior of the cement‐bone interface under tension‐compression loading conditions. These experiments were simulated using finite element analysis (FEA) to test whether the micromechanical response of the interface could be captured in micromodels. Models were created of experimental specimens based upon microcomputed tomography data, including the complex interdigitated bone‐cement morphology and simulated frictional contact at the interface. The models were subjected to a fully reversed tension‐compression load, mimicking the experimental protocol. Similar to what was found experimentally, the simulated interface was stiffer in compression than in tension, and the majority of displacement was localized to the cement‐bone interface. A weak correlation was found between the FEA‐predicted stiffness and the stiffness found experimentally, with average errors of 8 and 30% in tension and compression, respectively. The hysteresis behavior found experimentally was partially reproduced in the simulation by including friction at the cement‐bone interface. Furthermore, stress analysis suggested that cement was more at risk of fatigue failure than bone, concurring with the experimental observation that more cracks were formed in the cement than in the bone. The current study provides information that may help explain the load transfer mechanisms taking place at the cement‐bone interface. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1312–1318, 2009     

椎体成形术中骨水泥弥散分布等级的量效关系

目的 提出椎体成形术骨水泥弥散等级分级理论,对不同等级下的止痛效果、腰椎功能进行评价.方法 收集椎体成形术患者57例,根据正侧位X线片简便判断出骨水泥分布等级并进行分组,对术前、术后1周、术后3个月各组间止痛效果、腰椎功能障碍指数进行比较.结果 57例获得平均7个月的随访.57例中14例出现椎体周围骨水泥外渗的情况,未出现神经症状或原有症状加重,每个椎体内注入骨水泥量1.5～5.0(2.6±1.1)ml,57例根据骨水泥弥散等级分为3组,VAS、ODI评分各组内术后与术前比较差异有统计学意义(P＜0.001);术后1周、3个月的组间VAS评分差异无统计学意义(P＞0.05),但在术后1周1级组与3级组ODI评分差异有统计学意义(P ＜0.05);而3个月后各组间ODI评分差异无统计学意义(P＞0.05).结论 经皮椎体成形术(PVP)各级骨水泥弥散等级均可有效缓解椎体压缩骨折引起的疼痛,疼痛缓解程度与骨水泥弥散程度不成比例关系;但在椎体成形术后早期骨水泥弥散等级对脊柱功能障碍指数影响存在统计学意义,认为该分级方法对PVP术后早期脊柱功能评价存在临床指导意义.     

Factors affecting flexural strength in cement within cement revisions

Cement within cement revisions provide substantial benefits for conventional revision yet remains uncommon possibly because of the perceived weakness of the cement-cement interface. This study investigated the flexural strength of beams composed of 2 different cements, exploring the factors of pore size, fracture location, viscosity, and the surface roughness of the interface. We found no significant difference when comparing combinations of different cements (P = .30), varying pore sizes (P = .13), or surface roughness (P = .39). Differences in fracture locations and viscosity combinations approached statistical significance (P = .08 and .05, respectively). Our findings suggest strong bonding between cements at the interface, with other factors being more important causes of weakness. Thus, we recommend that the strength of the cement-cement interface should not be a factor when considering such revisions.     

Dual antibiotic loaded bone cement in patients at high infection risks in arthroplasty: Rationale of use for prophylaxis and scientific evidence

In view of the demographic changes and projected increase of arthroplasty procedures worldwide, the number of prosthetic joint infection cases will naturally grow. Therefore, in order to counteract this trend more rigid rules and a stricter implementation of effective preventive strategies is of highest importance. In the absence of a "miracle weapon" priorities should lie in evidence-based measures including preoperative optimization of patients at higher infection risks, the fulfilment of strict hygiene rules in the operating theatre and an effective antibiotic prophylaxis regimen. Instead of a "one size fits all" philosophy, it has been proposed to adjust the antibiotic prophylaxis protocol to major infection risks taking into account important patient-and procedure-related risk factors. A stronger focus on the local application mode via use of high dose dual antibioticloaded bone cement in such risk situations may have its advantages and is easy to apply in the theatre. The more potent antimicrobial growth inhibition in vitro and the strong reduction of the prosthetic joint infection rate in risk for infection patients with aid of dual antibiotic-loaded bone cement in clinical studies align with this hypothesis.     

经皮椎体成形术中骨水泥弥散容积比与疗效相关性的临床研究

目的 评价椎体成形术中骨水泥弥散容积比与疗效的关系。方法 2016年1月至2018年5月,43例骨质疏松性椎体压缩骨折患者在我科施行经皮椎体成形术,术后Mimics软件上计算出伤体内骨水泥弥散容积。骨水泥弥散容积比=骨水泥弥散容积/伤锥体积,将骨水泥弥散容积比分为3级,1级<25%,25%<2级<50%,3级>50%,对比术前与术后随访（12个月）的模拟VAS评分与腰疼ODI评分。结果 37例患者实施PVP,术后获12~27个月随访（平均16.8个月）,患者背部疼痛均有不同程度缓解或者消失。骨水泥弥散容积比分为1级、2级、3级各组之间的疼痛缓解疗效的差异无统计学意义（P>0.05）。结论 经皮椎体成形术中骨水泥弥散容积比<25%即可获得满意疗效,增加骨水泥弥散容积比不能获得更好的疗效。     

The Formation of Stress by Acrylic Bone Cements During Fixation of the Acetabular Prosthesis

The forces developed by acrylic cement during the final phase of polymerization under conditions that simulate the cementing of the acetabular prosthesis are evaluated. Calculations show that forces of 500–1100 N may be reached in a three-point fixational system. the importance of the dimensions of the plastic and the bone and the relevance of the E-moduli are discussed.     

The Relaxation of Some Acrylic Bone Cements

The creep and relaxation of acrylic cements during conditions simulating the conditions in the acetabulum have been examined. CMW and Simplex were found to reach stresses of about 10 N/cm² after 1 year whereas Palacos had lost most of its stress after 6 weeks.     

新型椎弓根钉骨水泥强化系统的生物力学与骨水泥剂量关系

目的建立骨质疏松模型,研究骨质疏松情况下新型经皮长U形空心椎弓根钉骨水泥强化系统(PMI-NPPS)的生物力学与骨水泥剂量之间的关系。方法取年龄在2.5~3.0岁绵羊腰椎,根据羊腰椎大小定做特定尺寸的羊PMI-NPPS。将40个椎体分成A、B组,B组脱钙4 h,分别进行骨密度测量,统计学分析确认骨质疏松模型建立。制备50个骨质疏松椎体随机分成5组,置入羊PMI-NPPS及骨水泥,按剂量分为0 ml组、0.5 ml组、1.0 ml组、1.5 ml组、2.0 ml组,进行生物力学测试,然后得出骨水泥剂量与Fmax(最大拔出力)的关系。结果 A组骨密度值为(0.875±0.003)g/cm~3、B组骨密度值为(0.631±0.003)g/cm~3,B组骨密度值低于A组,差异有统计学意义(P0.05)。脱钙后椎体骨密度较脱钙前降低27.9%。0 ml组、0.5 ml组、1.0 ml组、1.5 ml组、2.0 ml组的Fmax分别为(372.34±47.96)N、(613.85±30.37)N、(760.64±51.18)N、(896.59±47.97)N、(1 011.59±47.97)N。Pearson相关分析结果提示骨水泥剂量与Fmax呈直线相关,线性回归方程为y=312.5x+418.75(R~2=0.977),且1.5 ml为最理想的骨水泥剂量。结论当骨水泥剂量为0~2 ml时,随着骨水泥剂量的增加,羊PMI-NPPS的Fmax越高,且呈线性相关;当骨水泥剂量为1.5 ml时,羊PMI-NPPS的Fmax可达到正常骨密度时内固定的强度。