MRI of bone marrow in the distal radius: in vivo precision of effective transverse relaxation times

The effective transverse relaxation time T2^* is influenced by the presence of trabecular bone, and can potentially provide a measure of bone density as well as bone structure. We determined the in vivo precision of T2^* in repeated bone marrow measurements. The T2^* measurements of the bone marrow of the distal radius were performed twice within 2 weeks in six healthy young volunteers using a modified water-presaturated 3D Gradient-Recalled Acquisition at Steady State (GRASS) sequence with TE 7, 10, 12, 20, and 30; TR 67; flip angle (FA) 90 °. An axial volume covering a length of 5.6 cm in the distal radius was measured. Regions of interest (ROIs) were determined manually and consisted of the entire trabecular bone cross-section extending proximally from the radial subchondral endplate. Reproducibility of T2^* and area measurements was expressed as the absolute precision error (standard deviation [SD] in ms or mm²) or as the relative precision error (SD/mean × 100, or coefficient of variation [CV] in %) between the two-point measurements. Short-term precision of T2^* and area measurements varied depending on section thickness and location of the ROI in the distal radius. Absolute precision errors for T2^* times were between 1.3 and 2.9 ms (relative precision errors 3.8–9.5 %) and for area measurements between 20 and 55 mm² (relative precision errors 5.1–16.4 %). This MR technique for quantitative assessment of trabecular bone density showed reasonable reproducibility in vivo and is a promising future tool for the assessment of osteoporosis. Correspondence to: S. Grampp     

小肠黏膜下层修复骨关节损伤的研究进展

作为天然细胞外基质生物衍生材料,小肠黏膜下层(small intestinal submucosa,SIS)可用作组织工程的理想支架,在修复组织缺损和实现组织重塑方面具有广阔的应用前景。近年来,SIS在修复骨关节损伤方面的应用逐渐增多,研究发现SIS对骨、半月板、韧带或肌腱均表现出良好的修复效果,但是在关节软骨、腱骨愈合等方面的具体作用还有待进一步探索。新型SIS修复材料的开发,也将是亟待解决的焦点问题和进一步研究的热点。     

Coralline hydroxyapatite bone graft substitutes in a canine metaphyseal defect model: radiographic-biomechanical correlation

Radiographic and biomechanical assessment of a new type of bone graft substitute derived from reef-building sea coral was performed in a canine metaphyseal defect model. Blocks of this material and autogenous iliac crest graft were implanted, respectively, into the right and left proximal tibial metaphyses of eight dogs. Qualitative and quantitative radiographic evaluation was performed in the immediate postoperative period and at 6 months after surgery. Biomechanical testing was carried out on all grafts following harvest at 6 months, as well as on nonimplanted coralline hydroxyapatite and autogenous iliac cancellous bone. In contrast to autografts, incorporation of coralline implants was characterized by predictable osseous growth and apposition with preservation of intrinsic architecture. Greater percent increase in radiographic density, higher ultimate compressive strength, and lower stiffness with incorporation were documented advantages of coralline hydroxyapatite over autogenous graft. Densitometric measurements correlated moderately with strength for both types of graft material (r=-0.65). These promising results have important implications to the clinical application of coralline hydroxyapatite bone graft substitutes as an alternative to autogenous grafting.Presented in part at the 29th Annual Meeting of the Orthopaedic Research Society, Anaheim, California, March 8–10, 1983     

Musculoskeletal infections: ultrasound appearances

Musculoskeletal infections are commonly encountered in clinical practice. This review will discuss the ultrasound appearances of a variety of musculoskeletal infections such as cellulitis, infective tenosynovitis, pyomyositis, soft-tissue abscesses, septic arthritis, acute and chronic osteomyelitis, and post-operative infection. The peculiar sonographic features of less common musculoskeletal infections, such as necrotizing fasciitis, and rice body formation in atypical mycobacterial tenosynovitis, and bursitis will also be presented.     

Two cases of membranous lipodystrophy (NASU)

Two cases of membranous lipodystrophy (T. Nasu) were reported in 24- and 32-year-old men. The roentgenogram showed multiple symmetrical radiolucencies of limb bones where the marrow fat was replaced by numerous characteristic undulating membranes. These membranes consisted of complicated membrane structures, the inner side of which proved to be smooth membrane structures under the electron microscope. Numerous minute tubular structures projected perpendicular to the interstitium from the inner smooth membrane structures. The microscopical findings of subcutaneous fat tissue were described, and the histogenesis of membrane structures under the electron microscope was reported.     

Three‐Dimensional Printing‐Assisted Masquelet Technique in the Treatment of Calcaneal Defects

ObjectiveThe aim of the present study was to summarize the clinical efficacy of three‐dimensional (3D) printing technology combined with the Masquelet technique in the treatment of calcaneal defects.MethodsFrom January 2018 to April 2019, 3D printing combined with induced masquelet technology was used to treat four patients with calcaneal defects, including two men and two women. The patients were aged 22–52 years old, with an average age of 36 years. There were two cases of traffic accident injuries, there was one case of a fall from height, and there was one case of crush injury. CT scans were used to reconstruct the bilateral calcaneus, mirror technology was used to construct the bone defect area, and Materialise 3‐matic software was used to design the calcaneus shaper mold and 3D print the mold. During the operation, the mold was used to shape the bone cement and fill the bone defect. In the second stage, the bone cement was removed and autologous bone was implanted to repair the bone defect. All patients were followed up to observe the effect.ResultsAll four patients were followed up for 14 months (range, 10–18 months). There were three cases of infectious bone defects: two cases of Escherichia coli and one case of Pseudomonas aeruginosa. The 3D printed mold was used to shape the bone cement. During the operation, it was found to have a high degree of matching with the defect area of calcaneus. There is no need to adjust it again, and the wound healed well after the first stage. In the second stage of surgery, it was found that the induced membrane formed was complete and of appropriate size; the bone cement was easily removed during the operation. The fracture healing time was 3–6 months, with an average of 4 months. At the last follow up, there was no pain and the patients walked with full weight bearing. The Maryland score was 94 points (range, 88–98 points); three cases were excellent and one case was good. The AOFAS score ranged from 86 to 98, with an average of 92.8 points; three cases were excellent and one case was good.ConclusionThree‐dimensional printing technology combined with induced membrane technology is an effective approach for treating calcaneal bone defects.     

纤维性骨皮质缺损的影像学诊断

目的分析纤维性骨皮质缺损（FOCD）的X线、CT及MRI表现及其诊断价值。方法回顾分析11例纤维性骨皮质缺损的X线、CT及MRI表现,全部经穿刺活检或手术病理证实。结果纤维性骨皮质缺损发生存股骨4例,胫骨3例,肱骨及腓骨各2例。在X线平片上FOCD病灶表现为三角形或碟形骨质破坏边缘有硬化,CT表现为半圆或三角形骨缺损,内含软组织密度,MRI T1WI上呈低信号,T2WI上呈稍低或低信号。结论X线、CT和MRI可显示纤维性骨皮质缺损的影像特征,并具有较高的诊断价值。     

精神分裂症患者骨折内外固定术的疗效比较

目的:比较精神分裂症患者肢体骨骨折内-外固定术治疗的疗效。方法:44例精神分裂症骨折患者做内固定术25例(内固定组),做外固定术19例(外固定组)。结果:内固定组临床愈合21例(84.0%),延迟愈合4例(16.0%);外固定组临床愈合11例(57.9%),延迟愈合8例(42.1%)。结论:精神分裂症患者骨折最好采用内固定术,可降低延迟愈合并畸形愈合的发生率,也有利于精神症状的控制和治疗,减少专科护理和治疗难度,如期回归社会、回归家庭,有利于提高个体和家属的生活质量。     

北京郊区初中生骨量2002年与2009年比较

目的对2002年和2009年北京市同龄初中生的骨量进行比较,为促进我国儿童青少年骨骼健康提供基础数据。方法分别在2002年和2009年随机抽取北京市郊区12～14岁初中生323名和307名,采用双能量X线骨密度测量仪(DEXA)测量全身(躯干、上肢、下肢)和腰椎的骨矿物含量(BMC)和骨矿物密度(BMD)及体成分。结果 2009年13岁男生躯干BMD低于2002年同龄组,14岁男生下肢BMD高于2002年同龄组;2009和2002年12～14岁男生身高、体重、体成分及余部位骨量差异均无统计学意义。2009年12岁女生上肢BMC和BMD高于2002年同龄组,13岁女生躯干BMD、下肢BMC及14岁女生全身、下肢的BMC和BMD及腰椎、躯干的BMD低于2002年同龄组;2009年12岁女生的瘦体重高于2002年同龄组,14岁女生的身高、体重低于2002年的同龄组,其余指标差异无统计学意义。结论北京市郊区2002与2009年12～14岁男生骨量差异不大,女生差异明显。     

PLGA-[ASP-PEG]三嵌段基质材料对骨髓间充质干细胞黏附增殖及诱导成骨分化的研究

目的：探讨聚乳酸聚乙醇酸共聚物（poly lactic acid-co-glycolic acid,PLGA）-天冬氨酸（asparagic acid,ASP）-聚乙二醇（poly ethylene glycol,PEG）三嵌段多元共聚物上骨髓间充质干细胞（mesenchymal stem cells,MSCs）的黏附、增殖及成骨分化情况。方法：在PLGA支架材料中引入PEG和含有多个功能位点的ASP,制成PLGA-[ASP-PEG]三嵌段高分子支架材料。将材料与MSCs复合培养,以未改性的PLGA支架材料作对照,通过沉淀法、MTT法和考马斯亮蓝法分别检测MSCs的黏附和增殖变化。用成骨诱导培养基培养14d和28d,碱性磷酸酶（alkaline phosphatase,ALP）染色和钙结节染色了解MSCs成骨分化情况。结果：MSCs在PLGA-[ASP-PEG]材料表面贴壁生长,细胞数目明显多于对照组。细胞黏附率检测显示,PLGA-[ASP-PEG]表面MSCs的黏附性能和增殖能力明显高于对照组,差异有统计学意义（P〈0.05）。MTT比色实验显示MSCs在PLGA-[ASP-PEG]三嵌段材料上培养20d后,吸光度（A）值为1.336,约为对照组0.780的2倍。培养12d时,PLGA-[ASP-PEG]材料组的细胞蛋白含量为66.44μg/孔,对照组为41.23μg/孔。成骨诱导培养基培养后,ALP染色和钙结节染色均为阳性,PLGA-[ASP-PEG]三嵌段材料及其降解产物不影响MSCs的成骨分化。结论：PLGA-[ASP-PEG]能促进组织工程种子细胞在骨基质材料表面的黏附、增殖,并能较好地保持细胞的形态,对成骨分化无明显影响。