The epidemiology of fragility fractures: Is there a role for bone quality?

Fragility fractures, particularly those of the hip, vertebrae, and distal forearm, constitute a major public health problem. The two ultimate determinants of fracture are bone strength and propensity to trauma. Bone strength depends not only upon bone mass but also upon a variety of qualitative aspects of bone structure. These include its architecture, the amount of fatigue damage it has sustained, and changes in its bulk material properties, indices that are collectively subsumed into the term bone quality Fragility fractures show differences in their patterns of incidence by age, sex, ethnic group, geographic area, and season. Many of these differences are currently unexplained, and disorders of bone quality might contribute to them. There are two fracture sites at which evidence implicates bone quality more directly—the spine and proximal femur. Many vertebral compression fractures follow minimal trauma, and controlled studies suggest that vertebral microarchitecture contributes to fracture risk independently of vertebral bone mass. At the hip, observational studies have pointed to a role for disordered trabecular architecture, accumulation of microfractures (fatigue damage), and the accumulation of osteoid. The extent to which these phenomena act independently of bone mass, however, remains uncertain.Presented at the NIA Workshop on Aging and Bone Quality, September 3–4, 1992, Bethesda, Maryland     

骨折与无骨折史患者的定量超声检查比较

目的：用定量超声方法对有骨折史的骨质疏松症患者进行骨量检查,方法用CUBA Clinical型定量骨密度超声仪对393例被疑为骨质疏松的患者进行检测,并根据病史按有无骨折中进行分组。分析二组患者宽频超声衰减（BUA）、超声速率（VOS）、强度指数（SI）与骨折次数的关系。结果：伴有骨折史的骨质疏松症虱的BUA、VOS、SI值都要比无骨折史的患者明显降低（P＝0．000）。结论定量超声值与骨折的发生次数呈负相关,其测定值越低,骨折的发生次数越多;骨的质量下降是造成骨质疏松骨折的主要原因。     

双极人工股骨头置换术治疗高龄股骨颈骨折

目的 通过对６６例７０岁以上老年人股骨颈骨折临床分析,探讨其手术可行性、术式选择。方法 回顾分析患者的术前并存症、术前准备、术式选择、麻醉方式、术中情况、术后处理及随诊情况。结果 本组无术中死亡病例,平均住院２８天,平均随访２６个月。良好率６３．６％。结论 ７０岁以上老人股骨颈骨折行双极股骨头置换术治疗是可行的。     

Cranial burst fracture in infants: acute recognition and management

In the past, the diagnosis of growing skull fracture or diastatic fracture has included a subset of injuries better referred to as cranial burst fracture. Cranial burst fracture, typically associated with severe injury in infants less than 1 year of age, is a closed, widely diastatic skull fracture accompanied by acute cerebral extrusion outside the calvarium. We treated 11 such infants at the LeBonheur Children's Medical Center and 2 at the Children's National Medical Center from January 1986 through December 1994. Infants ranged in age from 1 to 17 months, with an average age of 5.7 months. All presented with marked scalp swelling and a Glasgow Coma Scale score of 10 or less. Twelve had a history consistent with severe injury (motor vehicle accident, 7, abuse 5). The cause of injury in one patient remains unproven. Surgery (reduction of herniated cerebral tissue, repair of large dural laceration, and cranioplasty) was usually performed within 10 days of injury, a time period long enough to assure hemodynamic stability and resolution of acute cerebral swelling, yet sufficiently brief to avoid the chronic changes (scarring, parasitization of scalp vessels by damaged cortex) associated with a growing skull fracture. Prompt repair of cranial burst fracture may prevent ongoing brain injury such as has been neuropathologically demonstrated in patients with growing skull fracture. Magnetic resonance imaging establishes the diagnosis of cranial burst fracture in equivocal cases, rendering unnecessary a waiting period to see if scalp swelling resolves. Our experience, together with information in the neuropathological and neurosurgicla literature, suggests that cranial burst fracture is associated with severe trauma, requires expeditious treatment, and has been underdiagnosed in the past, leading to growing skull fracture, a condition requiring more extensive surgery.     

Introduction

The number of femoral fractures after hip arthroplasty has increased proportionally to the number of hip arthroplasties. Eleven university-orthopaedic centers in eastern France co-operated to review 250 femoral fractures in relation to hip prothesis. This is the largest published review. The aims of this retrospective study were:

An unusual cause of depressed skull fracture: case report

BACKGROUND: Camel collision accidents are a common occurrence in Saudi Arabia, with a high rate of mortality and morbidity. Isolated injuries are rare because of the nature of impact sustained by the person. CASE DESCRIPTION: A 4-year-old child with an isolated depressed skull fracture resulting from a camel collision is described. The other occupants of the car were crushed to death. The child sustained only an impact to his head, causing a compound depressed skull fracture with localized cortical damage. CONCLUSIONS: Camel collision accidents are a common cause of mortality and morbidity in Saudi Arabia. Isolated skull injuries are rare and result from a localized impact. This is the first report of a compound depressed skull fracture from such an incident. The extent of the problem and efforts toward prevention are described.     

Generalized amyloidosis from β2-microglobulin,with caecal perforation after long-term haemodialysis

Summary A 73-year-old man with chronic renal failure of undetermined aetiology had received haemodialysis for 12 years when he died of acute purulent peritonitis due to caecal perforation. Amyloid deposits detected in a cystic bone lesion in the left hip had caused a pathological fracture 17 days before death. At autopsy, extensive amyloid deposits were found in the osteoarticular system, in the cartilaginous surface and the capsular tissue of joints, ligaments, vertebral discs and bone. In addition, vascular amyloid deposits were diagnosed in the heart, kidneys, testes, lungs, skin and in the gastrointestinal tract. A special feature of this case were interstitial amyloid deposits forming a fine-meshed structure in the myocardium and plate-like deposits in the gastrointestinal tract. Immunohistochemically, all these deposits reacted strongly with antibody to human ₂-microglobulin but showed no reaction with antibodies to AA, Alambda, A-kappa and AF. The present case demonstrates that extra-osteoarticular manifestations of AB-amyloidosis can cause serious complications.     

Effects of dexamethasone on the differentiation of membrane structure in cultured astrocytes.

Astrocytic processes investing vascular structures or forming the surface of mammalian brain have large numbers of orthogonally packed aggregates of intramembrane particles, termed "assemblies." Similar particle aggregates are expressed by astrocytes derived from neonatal rat forebrain in secondary culture, but they are much more uniformly distributed across the membranes of the cultured cells. Dexamethasone, a potent glucocorticoid, affects the differentiation of astrocyte membrane structure in two patterns, depending on the rate of proliferation in the culture. When confluent secondary cultures of astrocytes are exposed to 5 microM dexamethasone, the densities of assemblies increase, and in some cells approach the values present in the glial limitans in vivo. However, when rapidly proliferating astrocytes are exposed to dexamethasone during the first week of secondary culture, most of the astrocytes fail to express any assemblies. The rate of astrocyte proliferation is slowed, and a lower cell density is reached during the first 2 weeks of secondary culture in dexamethasone. The suppression of assemblies is transient: as the cultures approach confluence, the proportion of cells expressing assemblies increases to nearly control levels, and the density of assemblies increases to greater than control values in some astrocytes. Certain of the effects of dexamethasone on cultured astrocytes may have relevance for understanding the mechanism(s) of its action in treating cerebral edema.     

骨科下肢侧卧位手术牵引架的研制及临床应用

目的研制并临床验证一种简便、实用、灵活、科学的骨科下肢侧卧位手术牵引架.方法1999年1月～2003年1月采用本手术设备共进行了51例均在侧卧位状态下进行的手术;其中股骨粗隆间骨折23例、股骨粗隆下骨折4例,行DHS22例、Gamma钉5例;股骨中下段骨折24例,行股骨交锁钉3例、梅花钉3例、LCDCP18例.结果采用本手术设备的手术情况是DHS、Gamma钉组的平均手术时间为51±19min、出血量为100士57ml,交锁钉组的手术时间为70±19min、出血量为312±94ml;与常规的仰卧位手术比较P＜0.01,同时方便C-臂X光机透视,尤其是侧位透视.此外,还可运用本手术设备进行股骨中下段骨折的其他各种内固定手术,牵引效能好,方便术区皮肤消毒及术中骨折复位.结论本骨科下肢侧卧位手术牵引架结构简单、零部件少、装卸容易、适应症广、操作方便、利于C-臂X光机透视,术中出血量少、损伤小、手术时间短,具有较好的实用型、先进性、科学性,值得临床推广应用.     

Fractographic Examination of Racing Greyhound Central (Navicular) Tarsal Bone Failure Surfaces Using Scanning Electron Microscopy

The greyhound is a fatigue fracture model of a short distance running athlete. Greyhounds have a high incidence of central (navicular) tarsal bone (CTB) fractures, which are not associated with overt trauma. We wished to determine whether these fractures occur because of accumulation of fatigue microdamage. We hypothesized that bone from racing dogs would show site-specific microdamage accumulation, causing predisposition to structural failure. We performed a fractographic examination of failure surfaces from fractured bones using scanning electron microscopy and assessed microcracking observed at the failure surface using a visual analog scale. Branching arrays of microcracks were seen in failure surfaces of CTB and adjacent tarsal bones, suggestive of compressive fatigue failure. Branching arrays of microcracks were particularly prevalent in remodeled trabecular bone that had become compact. CTB fractures showed increased microdamage when compared with other in vivo fractures (adjacent tarsal bone and long bone fractures), and ex vivo tarsal fractures induced by monotonic loading (P < 0.02). It was concluded that greyhound racing and training often results in CTB structural failure, because of accumulation and coalescence of branching arrays of fatigue microcracks, the formation of which appears to be predisposed to adapted bone. Received: 12 November 1999 / Accepted: 10 March 2000