Contemporary bone loss options: Rebuild,reinforce, and augment

Bone loss is commonly encountered during revision total knee arthroplasty (TKA). Small defects can be adequately managed with cement filling (with or without screws), modular prosthetic augments, and morselized allograft. For larger defects, cancellous impaction grafting and structural allografts have traditionally been utilized. More recently, highly porous tantalum cones and titanium sleeves have been designed to achieve axial and rotational stability in the metaphysis and subsequent biologic fixation. Sleeves are linked to one type of prosthesis, whereas cones are unlinked and can be used with any implant design. Multiple studies have demonstrated excellent survivorship and radiographic osseointegration at mid-term follow-up. This article provides a review of contemporary methods of bone loss management with a focus on highly porous metals and an emphasis on the authors’ preferred method for managing the severe bone loss in revision TKA.     

An Evidence-Based Review of Total Body Irradiation

The purpose of this literature review is to investigate clinical treatment methods of total body irradiation within the context of a clinical department adopting a paediatric cohort with no existing technique. An extensive review of the literature was conducted using PubMed, Science Direct, Google Scholar, and Clinicians Knowledge Network. Articles were limited to nonhelical tomotherapy, nonparticle therapies, and those using hyperfractionated regimes. Total marrow irradiation was excluded because of national treatment and trial limitations. Of the numerous patient positioning methods present within the literature, the most comfortable and reproducible positioning methods for total body irradiation include both supine and the supine and/or prone combination. These positions increased stability and patient comfort during treatment, while also facilitating computed tomography data acquisition at the simulation stage. Ideally, dose calculations should be performed using a three-dimensional treatment planning system and quality assurance procedures that include in vivo dosimetry measurements. The available literature also suggests inhomogeneity correction factors and intensity modulation are superior to conventional open field techniques and should be implemented within developing protocols. Dynamic machine dose modulation is suggested to reduce department impact, removing the need for tissue compensators and accessory shielding devices, while providing significant improvements to treatment time and dose accuracy. Further long-term survival and intensity modulation studies are warranted, including direct comparisons of both dose modulation and treatment efficiency.     

后路枕骨髁螺钉技术研究进展

正枕骨、寰椎和枢椎共同构成了枕颈部活动的结构功能单位,即枕颈交界区~([1-2])。炎症、创伤、肿瘤及畸形等因素会导致枕颈交界区失稳,从而引起颈脊髓或神经根的损伤、麻痹及难以忍受的疼痛,甚至危及生命~([3-4])。后路内固定融合技术是治疗枕颈部失稳的重要手段,目前常用术式为枕骨螺钉技术,该技术较钢丝固定技术有更好的生物力学稳定     

Clinical and subclinical cardiovascular disease in female SLE patients: Interplay between body mass index and bone mineral density

Background and aims

Since accelerated atherosclerosis has been reported in systemic lupus erythematosus (SLE), predictive biomarkers of cardiovascular disease (CVD) are needed. Among non-traditional risk factors, bone mineral density (BMD) has been related to CVD. However, its role in SLE remains controversial. This study aims to analyze the associations of subclinical atherosclerosis with traditional and non-traditional CV risk factors.

上肢骨肿瘤切除后的自体骨移植重建

目的探讨应用自体骨移植对上肢骨肿瘤切除后的骨缺损修复重建的效果。方法1998年8月～2004年3月，收治上肢骨肿瘤切除后的骨缺损16例。男8例，女8例。年龄7～45岁。经病理确诊，肱骨近端尤文肉瘤和骨肉瘤各1例；肱骨远端尤文肉瘤2例；桡骨远端骨巨细胞瘤8例，高分化软骨肉瘤2例，恶性纤维组织细胞瘤和骨肉瘤各1例。2例肱骨近端肿瘤行自体锁骨代肱骨；2例肱骨远端肿瘤行自体腓骨代肱骨；12例桡骨远端肿瘤中，1例行自体髂骨移植，11例行自体腓骨代桡骨进行重建。采用MSTS系统进行术后功能评价。结果2例肱骨近端自体锁骨移植患者分别随访36个月和12个月，术后保持部分肩关节前屈和后伸功能，但外展功能丧失；MSTS评分分别为23分和22分。2例肱骨远端自体腓骨移植患者分别随访4个月和6个月，肘关节功能良好，移植骨连接处已经出现骨愈合；MSTS功能评分分别为24分和19分。12例桡骨远端自体骨移植患者中11例随访6～75个月，功能良好，无明显并发症；1例髂骨植骨的桡骨远端骨巨细胞瘤术后3个月移植骨完全愈合，至今随访75个月，肿瘤无复发。MSTS功能评分18~27分，平均22．6分。结论自体骨移植在上肢骨肿瘤切除后骨缺损的重建，尤其是儿童的骨缺损重建中，是一种较好的方法。     

带浅静脉干逆行皮瓣早期微血管构筑变化的体视学研究

目的 探讨带浅静脉干的逆行皮瓣早期微血管构筑变化的特点以供临床实践参考。方法 应用生物体视学技术测量带浅静脉干皮瓣微血管体积密度，结合组织学观察，与不带静脉干皮瓣作对照比较。结果 带浅静脉干皮瓣组微血管密度整体水平高于不带静脉干皮瓣组（P〈0．05）。结论 浅静脉干的存在有利于皮瓣的血管化进程，保留浅静脉干对皮瓣成活有利。     

高转换型肾性骨病中骨保护素及其配体的表达和形态计量学观察

目的 观察高转换型肾性骨病中骨保护素及其配体 (OPG，RANKL)的表达，并与骨形态计量学指标进行相关分析。 方法 选择10例慢性肾衰尿毒症患者和3例正常人进行髂骨活检术，获得骨组织标本。采用免疫组化方法检测OPG和RANKL蛋白质的表达。采用全自动图像分析系统进行骨组织形态计量学测定。结果 10例慢性肾衰尿毒症患者经骨病理学检查证实均为高转换型骨病，以破骨细胞活化形成骨吸收陷窝伴或不伴骨矿化不全为特点。免疫组化显示尿毒症患者骨组织中以RANKL阳性表达为主。与正常对照相比，RANKL阳性表达细胞数目显著增加，OPG阳性表达细胞数目显著减少。尿毒症患者RANKL的阳性表达细胞数目与骨吸收面积和破骨细胞数目呈显著正相关。结论 高转换型肾性骨病中，PTH的溶骨作用可能是通过OPG/RANKL/RANK系统介导的。     

Relationship between insulin-like growth factor I, dehydroepiandrosterone sulfate and proresorptive cytokines and bone density in cystic fibrosis

Introduction Patients with cystic fibrosis (CF) are known to be at risk for early osteoporosis, and the mechanisms that mediate bone loss are still being delineated. The aim of the present investigation was to investigate if a correlation exists in these patients between skeletal measurements by dual-energy x-ray absorptiometry (DXA) and two anabolic factors, dehydroepiandrosterone (DHEA) and insulin-like growth factor I (IGF-I), and proresorptive factors such as the cytokines interleukin-1β, tumor necrosis factor α, and interleukin-6. Methods We studied 32 outpatients (18 females; mean age: 26.2 ± 7.9 years) at a tertiary care medical center. The subjects had venous samples obtained, underwent anthropometric and bone mineral density (BMD) measurements, and completed a health survey. Serum IGF-I concentrations were below the age-adjusted mean in 78% of the participants, and DHEA sulfate (DHEAS) concentrations were low in 72%. Serum concentrations of all cytokines were on the low side of normal; nonetheless, there was a modest inverse correlation between IL-1β and BMD at all sites. Results In univariate analyses, IGF-I and DHEAS were significant correlates of BMD or bone mineral content. In final multivariate models controlling for anthropometric and other variables of relevance to bone density, only IGF-I was identified as a significant independent skeletal predictor. While alterations in DHEAS, IGF-I, and specific cytokines may contribute to skeletal deficits in patients with CF, of these factors a low IGF-I concentration appears to be most strongly correlated with BMD. Conclusions These findings may have therapeutic implications for enhancing bone density in these patients.     

Novel explant model to study mechanotransduction and cell-cell communication.

To understand in situ behavior of osteocytes, we characterized a model of osteocytes in their native bone matrix and demonstrated real-time biologic activity of osteocytes while bending the bone matrix. Using 43 male Sprague-Dawley rats, dumbbell-shaped explants were harvested from stainless steel femoral implants after 6-12 weeks and incubated in culture medium or fixed. Sixteen specimens were used to determine bone volume density (BV/TV), volumetric bone mineral density (BMD) and histology for different implantation periods. Osteocyte viability was evaluated by L-lactate dehydrogenase (LDH) activity in 12 cultured explants. Confocal microscopy was used to assess tracer diffusion in three explants and changes in osteocyte pH of a mechanically loaded explant. From 6 to 12 weeks, explant BV/TV and volumetric BMD trended up 92.5% and 101%, respectively. They were significantly and highly correlated. Tissues were uniformly intramembranous and all bone cell types were present. Explants maintained LDH activity through culture day 8. Diffusion at 200 microM was limited to 1,209 Da. Explants appeared capable of reproducing complex bone biology. This model may be useful in understanding osteocyte mechanotransduction in the context of a physiologically relevant bone matrix.