股骨头无菌坏死的组织工程学修复的研究进展

股骨头无菌坏死是一种骨质血液供应受阻所导致的疾病,目前临床常用的治疗方法主要为姑息性手术治疗以及人工关节置换术。近年来,随着组织工程学的发展,该技术迅速被应用于股骨头无菌坏死的治疗中。本文就股骨头无菌坏死的病因、临床分期以及组织工程学在治疗股骨头无菌坏死的研究进展作一综述。     

不同消毒工具对气管切开伤口的影响

目的观察2种不同消毒工具对气管切开处伤口感染的影响。方法将50例行气管切开术的患者采用随机数字表法随机分为对照组与实验组各25例。实验组选用一种长20cm的无菌棉签对气管切开伤口进行消毒换药;对照组选用常规纱球对气管切开伤口进行消毒换药。观察两组患者气管切开伤口周围皮肤局部改变情况,计算伤口感染率。结果实验组患者气管切开伤口未发生感染,对照组患者气管切开伤口感染发生率为16．0％,组间比较差异具有统计学意义（x2=3．170,P〈0．05）。结论用灭菌的长棉签对气管切开伤口周围皮肤进行消毒换药可以降低伤口感染率,且便于护理人员操作,值得临床推广使用。     

Shear fatigue micromechanics of the cement–bone interface: An in vitro study using digital image correlation techniques

Loss of fixation at the cement–bone interface is known to contribute to aseptic loosening, but little is known about the mechanical damage response of this interface. An in vitro study using cement–bone specimens subjected to shear fatigue loading was performed, and the progression of stiffness changes and creep damage at the interface was measured using digital image correlation techniques. Stiffness changes and creep damage were localized to the contact interface between cement and bone. Interface creep damage followed a three‐phase response with an initial rapid increase in creep, followed by a steady‐state increase, concluding in a final rapid increase in creep. The initial creep phase was accompanied by an increase in interface stiffness, suggesting an initial locking‐in effect at the interface. Interface stiffness decreased as creep damage progressed. Power law models were reasonably successful in describing the creep and stiffness damage response and were a function of loading magnitude, number of loading cycles, and contact area at the interface. More microcrack damage occurred to the cement when compared to the bone, and the damage was localized along the interface. These findings indicate that damage to the cement–bone interface could be minimized by improving cement–bone contact and by strengthening the fatigue resistance of the cement. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:340–346, 2009     

Aseptic meningitis and ischemic stroke in relapsing polychondritis

Relapsing polychondritis (RP) is a rare disease characterized by recurrent inflammation of cartilaginous structures. Its involvement of central nervous system is uncommon. We report the case of a 71-year-old woman whose initial manifestations were RP and meningitis and whose subsequent attack of RP was associated with a left cerebral infarction. The patient responded to steroid therapy in both attacks of RP.     

Aseptic colon resection by an invagination technique

A new aseptic colon resection by an invagination technique is presented. The bowel to be resected is invaginated down into the healthy intestine, and the anastomosis is sutured in one layer of continuous suture before transection by a diathermy wire, placed in the intestinal lumen via the anus. Sections of bowel that cannot be invaginated,e.g.,because of a tumor, are first removed by transection between pairs of cable ties, which close the lumen. Twenty dogs were operated on without receiving prophylactic antibiotics. In 10, the intestine was transected between cable ties. An imprint, taken from the anastomosis and subcutis, was cultured. The bacterial count at the anastomosis exceeded 100 in only three cases; in the subcutis, this was the case in one dog. One wound infection developed. Serial barium enemas at 1, 2, 3, and 4 weeks revealed no anastomotic leakage. One early death because of a total anastomotic dehiscence was encountered, and two dogs were killed because of wound dehiscence and anastomotic stricture, respectively. It is concluded that, in dogs, the method is easily and safely performed, but further experimental studies are needed.This study was supported with grants from Fonden til Laegevidenskabens Fremme, Kraeftens Bekaempelse, Sygekassernes Helsefond, and Aarhus Universitets Forskningsfond.     

Twenty-three neutrophil granulocytes in 10 high-power fields is the best histopathological threshold to differentiate between aseptic and septic endoprosthesis loosening

Aims:  The histopathological diagnosis of infection in periprosthetic tissue from loose total joint endoprosthesis has been the subject of controversy. The aim was to define a histological criterion that would best differentiate between aseptic and septic endoprosthesis loosening.
Methods and results:  Neutrophilic granulocytes (NG) were enumerated histopathologically in 147 periprosthetic membranes obtained from aseptic and septic revision surgery, using periodic acid–Schiff (PAS) stains and CD15 immunohistochemistry. Cell numbers were correlated with the results of microbiological culture and the clinical diagnoses. Using receiver–operating characteristics, an optimized threshold was found at 23 NG in 10 high-power fields (HPF). Using this threshold, histopathological examination had a sensitivity of 73% and specificity of 95% when compared with microbiological diagnosis (area under the curve 0.881), and a sensitivity of 77% and specificity of 97% when compared with clinical diagnosis (area under the curve 0.891).
Conclusions:  We therefore recommend a counting algorithm with a threshold of ≥23 NG in 10 HPF (visual field diameter 0.625 mm) for the histopathological diagnosis of septic endoprosthesis loosening. If the enumeration of NG is difficult in conventional haematoxylin and eosin-stained slides, CD15 immunohistochemistry should be performed, whereas the PAS stain has not proven to be helpful .     

Effect of repeated torque/mechanical loading cycles on two different abutment types in implants with internal tapered connections: an in vitro study

Objectives: Internal tapered connections were developed to improve biomechanical properties and to reduce mechanical problems found in other implant connection systems. The purpose of this study was to evaluate the effects of mechanical loading and repeated insertion/removal cycles on the torque loss of abutments with internal tapered connections.
Material and methods: Sixty-eight conical implants and 68 abutments of two types were used. They were divided into four groups: groups 1 and 3 received solid abutments, and groups 2 and 4 received two-piece abutments. In groups 1 and 2, abutments were simply installed and uninstalled; torque-in and torque-out values were measured. In groups 3 and 4, abutments were installed, mechanically loaded and uninstalled; torque-in and torque-out values were measured. Under mechanical loading, two-piece abutments were frictionally locked into the implant; thus, data of group 4 were catalogued under two subgroups (4a: torque-out value necessary to loosen the fixation screw; 4b: torque-out value necessary to remove the abutment from the implant). Ten insertion/removal cycles were performed for every implant/abutment assembly. Data were analyzed with a mixed linear model ( P ≤0.05).
Results: Torque loss was higher in groups 4a and 2 (over 30% loss), followed by group 1 (10.5% loss), group 3 (5.4% loss) and group 4b (39% torque gain). All the results were significantly different. As the number of insertion/removal cycles increased, removal torques tended to be lower. It was concluded that mechanical loading increased removal torque of loaded abutments in comparison with unloaded abutments, and removal torque values tended to decrease as the number of insertion/removal cycles increased.