Prognostic Factors in Arthroplasty in the Rheumatoid Shoulder

Total shoulder arthroplasty is commonly considered a good option for treatment of the rheumatoid shoulder. However, when the rotator cuff and glenoid bone stock are not preserved, the clinical outcome of arthroplasty in the rheumatoid patients remains unclear. Aim of the study is to explore the prognostic value of multiple preoperative and peroperative variables in total shoulder arthroplasty and shoulder hemiarthroplasty in rheumatoid patients. Clinical Hospital for Special Surgery Shoulder score was determined at different time points over a mean period of 6.5 years in 66 rheumatoid patients with total shoulder arthroplasty and 75 rheumatoid patients with shoulder hemiarthroplasty. Moreover, radiographic analysis was performed to assess the progression of humeral head migration and glenoid loosening. Advanced age and erosions or cysts at the AC joint at time of surgery were associated with a lower postoperative Clinical Hospital for Special Surgery Shoulder score. In total shoulder arthroplasty, status of the rotator cuff and its repair at surgery were predictive of postoperative improvement. Progression of proximal migration during the period after surgery was associated with a lower clinical score over time. However, in hemiarthroplasty, no relation was observed between the progression of proximal or medial migration during follow-up and the clinical score over time. Status of the AC joint and age at the time of surgery should be taken into account when considering shoulder arthroplasty in rheumatoid patients. Total shoulder arthroplasty in combination with good cuff repair yields comparable clinical results as total shoulder arthroplasty when the cuff is intact.     

Novel method for selecting slices of the same cross-sectional view from digital tomosynthesis for monitoring posterior spinal instrumentation

BackgroundA method to evaluate pedicle screw loosening on digital tomosynthesis images is yet to be established owing to lack of methods for selecting slices of the same cross-sectional view. We aimed to develop an objective method for selecting slices of the same cross-sectional view on digital tomosynthesis images.MethodsFirst, an objective method of pixel selection was developed by measuring the size of glass disk and titanium alloy screw on digital tomosynthesis images followed by comparison with the actual sizes. Second, a method for selecting slices of the same cross-sectional view was explored on a bone model with posterior spinal instrumentation using the screw centerline and rod curvature as indicators of the same cross section. The angle between the screw centerline and rod was calculated to verify the accuracy in obtaining the same cross-sectional view. Third, the method for selecting slices of the same cross-sectional view was applied to six patients after posterior lumbar spinal instrumentation.ResultsThe pixel selection method enabled objective determination of a pixel on the peripheral lines of objects with an error as low as 200 μm in distance measurements on titanium alloy and glass. The mean differences of rod-screw angles between two slices were less than 1° and were not statistically significant in the bone model and patient images.ConclusionA method for selecting slices of the same cross-sectional view on digital tomosynthesis images was successfully developed. This method can enable objective and quantitative evaluations of pedicle screw loosening.     

Inducible Displacement of a Trabecular Metal Tibial Monoblock Component

Radiostereometric analysis is a highly accurate technique that can be used for measuring micromotion at the bone-implant interface. The purpose of this study was to compare the inducible displacement of the uncemented Trabecular Metal (TM; Zimmer, Warsaw, Ind) tibial monoblock component with that of a cemented implant. Inducible displacement of 14 uncemented TM components and 11 cemented components was measured 24 to 48 months postoperatively. Longitudinal migration of the implants was also measured with radiostereometric analysis at 6, 12, and 24 months postoperatively. The uncemented TM group had significantly lower inducible displacement than the cemented components. Significant correlations were found between longitudinal migration and the inducible displacement tests. The low values of inducible displacement in the TM group indicated good fixation and a promising long-term prognosis.     

Decrease in particle‐induced osteolysis in ovariectomized mice

Postmenopausal osteoporosis is a common disorder that results from increased osteoclastic activity caused by estrogen deficiency. Whether postmenopausal bone remodeling can alter the response to particulate debris is unknown. The purpose of this study was to evaluate the bone response to polyethylene particles in an ovariectomized murine model. Polyethylene particles were implanted onto the calvaria of seven control mice and seven ovariectomized (OVX) mice, as compared with calvaria from sham‐operated and OVX mice. Calvaria were harvested after 14 days. Skulls were analyzed with a high‐resolution micro‐CT and by histomorphometry after staining with Stevenel blue and picrofuschine, and for tartrate‐specific alkaline phosphatase. As assessed by micro‐CT, particle implantation induced a significant decrease in bone thickness in control mice, while bone thickness remained stable in OVX mice. In particle‐implanted animals, the osteoclast number was 2.84 ± 0.3 in control mice and 1.74 ± 0.22 in OVX mice. Mean bone loss was ?12% ± 1.9% in control mice and ?4.7% ± 1.7% in OVX animals. The reduction of osteolytic response suggests that ovariectomy may have a protective role against particle‐induced bone resorption. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:178–183, 2010     

The utility of dithiothreitol treatment of periprosthetic tissues and explanted implants in the diagnosis of prosthetic joint infection

PurposeThe methods used for the processing of periprosthetic tissues and explanted implants to improve culture outcome especially in biofilm mediated prosthetic joint infections (PJIs) are still debated upon. Studies have reported that Dithiothreitol (DTT) pretreatment of infected devices gives similar results as sonication. However, none of them evaluated the DTT treatment of periprosthetic tissues and explanted implants in the same cohort. We evaluated the diagnostic utility of DTT treatment of periprosthetic tissue and explanted implants, as compared to the normal saline treatment of periprosthetic tissues and sonication of explanted implants for the diagnosis of PJI.MethodsSeventy-three revision arthroplasty cases were prospectively included in this study. Three to five tissue specimens and the explanted implants were collected from each patient. Periprosthetic tissue samples were processed by both normal saline and DTT treatments. Explanted implants were subjected to both DTT treatment and sonication. Musculoskeletal Infection Society (MSIS) PJI criteria was used as the reference standard for the diagnosis of PJI.ResultsOf the 73 cases enrolled, 34 had PJI and 39 were aseptic failures. The sensitivity of DTT treated periprosthetic tissue culture (PTC) and saline treated PTC was similar (66.6% vs 58.8%, P = 0.25). The specificity of both was 100%. Sonication and DTT treatment of explanted implants showed comparable sensitivity (85.3% vs 82.4%) and specificity (100% vs 97.4%), P > 0.99. Compared to DTT treated PTC, culture of DTT treated explanted implants significantly improved the diagnosis of PJI (P = 0.03).ConclusionsWe could verify that DTT can be used to improve culture outcome in laboratories where biofilm detaching sonication techniques are not available for infected implants. In addition, we showed that it is possible to use DTT for treating tissue biopsies, but larger studies are required to confirm our findings.     

低强度超声对颅骨溶解模型小鼠磨损颗粒诱导的骨溶解效应的影响

目的:探讨低强度超声在小鼠颅骨溶解模型中对破骨细胞增殖分化的干预,为临床治疗关节松动提供理论依据。方法：选择30只BALB/c小鼠,按随机数字表法分为空白对照组、颗粒组和超声组,每组10只。采用改良磨损颗粒法复制小鼠颅骨溶解模型,在术后15 d获取小鼠颅顶骨骨组织标本,HE染色观察炎细胞渗出量和骨溶解面积变化;扫描电镜检测骨片吸收陷窝面积百分比;抗酒石酸酸性磷酸酶染色（TRAP）观察破骨细胞增殖分化;免疫组织化学染色定位观察损伤骨组织中骨保护素（OPG）的表达变化。结果：HE染色,与空白对照组比较,颗粒组和超声组炎细胞渗出量和骨溶解面积明显增加（P<0.01）;与颗粒组比较,超声组骨溶解面积明显降低（P<0.05）,而2组炎细胞渗出量比较差异无统计学意义（P>0.05）。扫描电镜,超声组骨片吸收陷窝面积百分比显著低于颗粒组（P<0.01）。TRAP染色,超声组破骨细胞数量明显低于颗粒组（P<0.01）。免疫组织化学,超声组OPG阳性细胞数明显高于颗粒组及空白对照组（P<0.05）。结论：低强度超声能抑制小鼠颅骨溶解模型中破骨细胞的增殖分化,有效降低聚乙烯磨损颗粒所致的骨溶解效应,从而增强关节假体周围骨的密度和强度,降低关节松动的发生率。     

脑实质内型表皮样囊肿临床特点及其治疗

目的探讨脑实质内型表皮样囊肿的临床特点及治疗方法。方法对27例脑实质内型表皮样囊肿的临床、影像表现及手术疗效进行回顾分析,并对术后无菌性脑膜炎的影响因素进行统计分析。结果肿瘤全切除20例,次全切7例。1例死亡,7例好转,3例复发。肿瘤直径、预防性腰椎穿刺、肿瘤全切、术腔冲洗,与无菌性脑膜炎相关(P<0.05),前二者经Logistic回归分析表明为最显著因素。结论全切肿瘤,地塞米松生理盐水冲洗术腔,术后做预防性腰椎穿刺引流,可以有效预防术后无菌性脑膜炎的发生。     

双蒂髂骨瓣转位移植治疗股骨头无菌性坏死

目的:探讨双髂骨瓣转位移植在治疗股骨头无菌性坏死疾患中的应用效果。方法:我们自1998年5月～1999年2月对应用双蒂髂骨瓣移位移植治疗股骨头无菌性坏死的28侧32髋进行临床观察。结果:根据王岩等制定的评定标准进行评定:优10例,良14例,可2例,差2例。结论:双蒂髂骨瓣转位移植可改善股骨头的血运,促进坏死区的修复与重建.具有可靠的疗效。     

Unverträglichkeit von Implantaten – Herausforderung für die Allergologie

Summary: With increasing distribution and use of various metal implants in modern medicine, there has been an aggravation of reported allergic reactions against metal implant materials in the last decades. For patients who received metal implants both localized and generalized eczema, urticaria, delayed wound healing, vasculitis, bullous disease and erythema exudativum like rashes have been described. Since metal implants are usually made of alloys containing nickel, cobalt and chromium these metals are presumed to be the deciding aetiologic factors as all of them are well known contact sensitizers. However, it is important to note that very often specific individual factors play a role in the pathology of these reactions as well. In accordance with aseptic loosening of metal implants cell infiltration around these implants are characterized by delayed type hypersensitivity. On the other hand, the complexity of all enrolled pathophysiological mechanisms makes it very difficult to determine and further characterize this reaction. Furthermore preoperatively performed epicutanous tests do not allow a reliable prediction of preexisting sensitisation against metals. For this reason more and more in vitro‐testing will be used in the future to assess metal allergy.     

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。