Incidence of postoperative complications and non- periprosthetic fractures after total hip arthroplasty: A more than 10-year follow-up retrospective cohort study

Objective: Postoperative complications and non-periprosthetic fractures (NPPFs), which was defined as a fracture existing non- periprosthetic implant, after total hip arthroplasty (THA) have a negative effect on the patients'' ability to perform activities of daily living. Thus, investigating these incidences of patients after THA will be valuable as it lead to a more strategic physical therapy interventions and advanced research to prevent these problems. The purpose of this study was to investigate the incidence of postoperative complications related to implants and NPPFs in patients after THA, a more than 10-year follow-up. Methods: This is a retrospective cohort study. A total 892 patients with hip osteoarthritis who underwent primary THA were analyzed (age at surgery was 45-79 years; 805 women; the average follow-up period was 12.4-year). The postoperative complications related to implants and NPPFs were calculated using data from their medical records. Results: The postoperative complications occurred in 37 patients, and NPPFs occurred in 72 patients, who were significantly older, and hip and knee OA diagnosis, compared to patients without NPPFs ( p <.05). The most common cause of NPPFs was minor trauma. In patients aged ≧ 65 years, significantly more NPPFs occurred during the first year after surgery( p <.05). Conclusion: More than 10-year after THA, the incidence of NPPFs was higher than that of postoperative complications related to implants. Older patients who had hip and knee OA were a significantly higher risk of developing NPPFs due to falls within the first year after surgery.     

Relationship between Perceived Leg Length Discrepancy at One Month and Preoperative Hip Abductor Muscle Elasticity in Patients after Total Hip Arthroplasty

Objective: Preoperative factors related to perceived leg length discrepancy (PLLD) after total hip arthroplasty (THA) are not well studied. This study aimed to examine the preoperative factors, including hip abductor modulus, related to PLLD one month after THA. Methods: The study included 73 patients diagnosed with osteoarthritis secondary to developmental dysplasia of the hip and a posterior approach to surgery. Multiple logistic regression analysis was performed using the presence or absence of PLLD as the dependent variable and preoperative hip abductor''s modulus of elasticity, pain, hip abduction range of motion, hip abductor muscle strength and pelvic obliquity as the independent variable. Additionally, receiver operating characteristic curves were used for the extracted variables for calculating the cutoffs, sensitivity, specificity and area under the curve (AUC) to determine the presence or absence of PLLD. The significance level was set at p<0.05. Results: The hip abductor modulus (odds ratio=1.13; 95% confidence interval=1.06-1.21; p<0.001) was selected as a preoperative factor. The cutoff value to determine the presence or absence of a PLLD was 16.32 kPa. The sensitivity and specificity were 81.8% and 72.5%, respectively, and the AUC was 0.8137. Conclusion: The hip abductor muscle elastic modulus affected PLLD one month after THA. If the preoperative hip abductor elastic modulus is higher than the cutoff value, it may affect the appearance of PLLD at one month postoperatively.     

Importance of knee flexion range of motion during the acute phase after total knee arthroplasty

Background: We investigate the association with knee flexion range of motion (ROM) during the acute phases and that at 12 months after total knee arthroplasty (TKA). We also clarified the cut-off ROM during the acute phases in predicting the goal of knee flexion ROM at 12 months. Methods: In this retrospective study, 193 patients with knee osteoarthritis (female:144 patients, age:73.2 ± 7.7 years) who underwent unilateral TKA at an orthopedic clinic were recruited. They underwent assessments of knee flexion ROM at 5 days, 1 month, and 12 months after TKA. The goal of knee flexion ROM at 12 months after TKA was set at 120°. Single and logistic-regression analyses were performed with the dependent variables including the outcome of the goal of knee flexion ROM at 12 months, and the independent variables included knee flexion ROM at 5 days and 1 month, separately. We calculated the cut-off ROM at 5 days and 1 month for predicting the goal of knee flexion ROM at 12 months with receiver operating curve analysis. Results: Knee flexion ROM at 5 days and 1 month were significantly associated with the goal of that at 12 months (p < 0.01). The cut-off ROM were 85° at 5 days and 105° at 1 month separately. Conclusions: Our results suggest the importance of early improvement in knee flexion ROM after TKA, and that at 1 month postoperatively indicates the likelihood of achievement of the goal of knee flexion ROM at 12 months after TKA.     

基于级联网络的膝关节图像分割与模型构建

采用膝关节模型进行电磁仿真是计算膝关节局部射频功率沉积（SAR）的主要方法,为了构建膝关节模型,本文提出了一种包含两个卷积神经网络——U-Net的级联网络结构,用于膝关节磁共振图像的分割．第一个网络在整幅图上分割肌肉、脂肪等占比较大的组织,并从分割结果中预测软骨与半月板的大致位置信息,第二个网络基于该信息在一个更小的子图上分割小组织以提高分割精度．两个网络均采用焦点损失函数,它们的分割结果合并在一起构成膝关节模型．我们将该方法与其它4种方法的分割结果进行了定量指标的对比研究,并分别构建膝关节模型,计算局部SAR值．结果表明本文提出的级联网络结构可以更精确的构建用于SAR仿真的膝关节模型．     

人工膝关节模拟试验机及其生物摩擦学性能评价研究进展

人工膝关节生物摩擦学模拟试验是在设计和制造阶段评价人工膝关节假体的主要方法.本文介绍了球面接触型、假体力和运动直接控制型及膝关节肌肉力重建型3类人工膝关节模拟试验机及其对应生物摩擦学研究现状,讨论了3类人工膝关节生物摩擦学试验的要求和特点,详细说明了现有人工膝关节生物摩擦学试验和测试标准,指出今后还需增加动物活体试验方式,扩大模拟人体运动测量范围,并应加强多因素同时作用下人工膝关节磨损机理研究,制定统一的人工膝关节生物摩擦学试验标准.     

一个解剖基人本下肢的生物动力模型：第二部分：数值结果

表述人体下肢生物动力模型的数值技术,数值结果并将其与献进行比较,模型显示：当人体下肢小腿受冲击外载荷作用时,在膝关节处所产生的４个主要韧带张力以及膝关节处的咬合接触力,在大腿固定不动（或运动受到约束）的情况下,要远大于大腿未受约束的情况下,要远大于大腿未受约束的情形,这与医学常识是吻合的。     

一个三维人膝关节弹性咬合的生物力学模型

基于人膝关节的解剖特征,在文献和试验的基础上,对膝关节解剖结构作了适当的简化,从而建立了一个完整的三维人膝关节弹性咬合的生物力学模型。     

人工膝关节置换中的生物力学研究进展

膝关节是人全身最大最复杂的关节, 它的任何一个主要组成部分的损坏都会引起膝关节的反常运动, 久之软骨和半月板发生磨损、变性而形成骨性关节病, 从而影响人的日常生活. 通常采用的方法是进行膝关节矫形或置换, 对严重病变的膝关节, 则采用全膝置换手术.随着人工膝关节置换成为非常普遍的外科手术, 与膝关节假体相关的研究也越来越多的被人所关注. 从生物力学角度对人工膝关节假体的类型和材料、假体生物力学性能的理论和实验研究、骨重建的理论模型、骨整合的理论和实验、与理论和实验相关的有限元分析模型等几个主要方面进行了详尽的综述. 同时, 指出了人工膝关节置换和目前研究中存在的问题,并对其未来的发展方向进行了一定的预测.      

膝关节镜下手术和药物辅助治疗半月板损伤疗效观察

目的探讨膝关节镜下手术修复和术后药物辅助治疗半月板损伤的疗效。方法对22例半月板撕裂的患者行膝关节镜下半月板修复术（其中16例从外到内缝合,6例从内到外缝合）,术后给予玻璃酸钠膝关节腔内注射辅助治疗,通过二期膝关节镜和MRI检查、Lysholm膝关节功能评分对治疗效果进行评价。结果22例患者膝关节镜下半月板修复术均取得成功。二期关节镜检查5例,显示半月板愈合良好;MRI复查17例,显示半月板愈合15例,未完全愈合和未愈合各1例;术后Lysholm平均评分较术前明显提高,差异具有统计学意义（P＜0.01）;疗效优14例,良6例,可1例,差1例,优良率90.9%（20/22）。结论膝关节镜下半月板修复术结合玻璃酸钠膝关节腔内注射治疗半月板损伤可取得良好的疗效。     

Effect of Body Weight-supported Walking on Exercise Capacity and Walking Speed in Patients with Knee Osteoarthritis: A Randomized Controlled Trial

Objective: To compare the effect of body-weight-supported treadmill training (BWSTT) and full-body-weight treadmill training (FBWTT) on patients with knee osteoarthritis (OA). Methods: Design was Randomized controlled trial. Patients with knee osteoarthritis (n = 30; mean age, 76.0±7.5 y) were randomly assigned to BWSTT or FBWTT group. All patients performed 20 min walking exercise twice a week for 6 weeks under the supervision of the therapist. Main measures were 10-meter walking test (10MWT), functional reach test (FRT), timed get up and go test (TUG), one-leg standing test, 6-minute walking test (6MWT), the parameters set on the treadmill, MOS Short-Form 36-Item Health Survey (SF36), Japanese Knee Osteoarthritis Measure (JKOM). Results: Twenty-five patients (10 men, 15 women; mean age, 76.5 ± 8.0 y) completed the experiment. Exercise capacity, indicated by the heart rate, was similar in both groups. After 3 weeks of BWSTT, the patients performed significantly better in the 10-m and 6-min walking tests. This was not the case with FBWTT even after 6 weeks training. Pain levels assessed were significantly improved after 3 weeks of BWSTT and 6 weeks of FBWTT. There were no significant improvements in either group assessed by the FRT, one-leg standing time test, TUG, or SF -36 questionnaire. Conclusions: BWSTT enhanced exercise capacity in terms of walking speed and pain reduction after 3 weeks; however, there was no significant improvement in patients'' functional abilities or quality of life.