Knee Images Digital Analysis (KIDA): a novel method to quantify individual radiographic features of knee osteoarthritis in detail

OBJECTIVE: Radiography is still the golden standard for imaging features of osteoarthritis (OA), such as joint space narrowing, subchondral sclerosis, and osteophyte formation. Objective assessment, however, remains difficult. The goal of the present study was to evaluate a novel digital method to analyse standard knee radiographs. METHODS: Standardized radiographs of 20 healthy and 55 OA knees were taken in general practise according to the semi-flexed method by Buckland-Wright. Joint Space Width (JSW), osteophyte area, subchondral bone density, joint angle, and tibial eminence height were measured as continuous variables using newly developed Knee Images Digital Analysis (KIDA) software on a standard PC. Two observers evaluated the radiographs twice, each on two different occasions. The observers were blinded to the source of the radiographs and to their previous measurements. Statistical analysis to compare measurements within and between observers was performed according to Bland and Altman. Correlations between KIDA data and Kellgren & Lawrence (K&L) grade were calculated and data of healthy knees were compared to those of OA knees. RESULTS: Intra- and inter-observer variations for measurement of JSW, subchondral bone density, osteophytes, tibial eminence, and joint angle were small. Significant correlations were found between KIDA parameters and K&L grade. Furthermore, significant differences were found between healthy and OA knees. CONCLUSION: In addition to JSW measurement, objective evaluation of osteophyte formation and subchondral bone density is possible on standard radiographs. The measured differences between OA and healthy individuals suggest that KIDA allows detection of changes in time, although sensitivity to change has to be demonstrated in long-term follow-up studies.     

不同类型的膝关节假体对站立时静态稳定性的影响研究

目的探讨人工全膝关节置换术(total knee arthroplasty,TKA)中选用固定平台(fixed-bearing)型(PFC-sigma)和旋转平台(rotating-platform)型(PFC-RP)膝关节假体对膝关节骨关节炎(knee osteoarthritis,OA)患者术后躯体静态稳定性产生的影响。方法对2011年1月至2013年12月在我院接受单侧TKA的OA患者45例(选用旋转平台型假体PFC-RP的患者21例,选用固定平台型假体PFC-Sigma的患者24例)进行分析。术前、术后6个月和术后1年时采用HSS评分标准对术侧膝关节进行功能评估,并用重心测量仪对患者进行站立平衡试验,连续记录躯体重心位置(gravity center position,GCP)。对GCP在水平方向上转移程度(medio-lateral displacement,ML-X range)以及GCP漂移轨迹(locus of GCP,LG)进行量化并分析两组患者之间的静态稳定性、术侧膝关节恢复情况以及术后并发症发生率的差异性。结果 TKA后单位时间内GCP在水平方向上平均位置由初始位置逐渐向术侧转移,且两组患者之间MLX range上变化程度差异均无统计学意义(P0.05),而选用PFC-RP型假体的患者LG水平明显较选用PFC-Sigma的患者小,且差异性有统计学意义(P0.05)。结论两组患者术后术侧膝关节恢复情况、并发症发生率无明显差异性,而选PFC-RP型假体的患者较PFC-Sigma的患者具有更好的静态时稳定性。     

Association between bone mineral density distribution and various radiographic parameters in patients with advanced medial osteoarthritis of the knee

PurposePatients with severe osteoarthritis (OA) of the knee have changes in bone mineral density (BMD) of the distal femur and proximal tibia. Correlations between the medial-to-lateral BMD (M/L-BMD) ratio (which normalizes the potentially confounding effects of body size and sex on BMD) and radiographic parameters that indicate OA progression have not been adequately studied. The purpose of this study was to evaluate correlations between radiographic indicators of OA progression and femoral and tibial M/L-BMD ratios.MethodsA consecutive series of 182 knees in 156 patients with advanced medial knee OA who underwent total knee arthroplasty were included. We evaluated correlations between the femoral and tibial M/L-BMD ratios and various radiographic parameters, including tibiofemoral angle (TFA), mechanical axis angle (MAA), tibial coronal angle, tibiofemoral subluxation (%), load-bearing axis deviation at the tibial plateau (%), and medial and lateral laxity.ResultsUnivariate analyses using Spearman's correlation coefficient revealed significant positive correlations between femoral and tibial M/L-BMD ratios and both TFA and MAA and negative correlations with tibial coronal angle and load-bearing axis deviation. Multivariate analyses showed significant associations between TFA and the femoral M/L-BMD ratio (β = 0.434, p < 0.001) and between MAA and the tibial M/L-BMD ratio (β = 0.384, p < 0.001).ConclusionBMD distribution around the knee might be predictable with radiographic parameters such as the TFA for the femur and MAA for the tibia. The findings of this study provide in vivo data on the evaluation of preoperative femoral and tibial M/L-BMD ratios without dual-energy X-ray absorptiometry.     

正常及骨性关节炎膝关节股骨远端旋转对线MRI比较研究

目的对正常及内翻畸形骨性关节炎膝关节行MRI测量,探讨股骨远端旋转对线的变化以指导临床。方法 MRI扫描60侧正常膝关节(A组)、40侧轻度(B组)及20侧重度(C组)内翻畸形骨性关节炎膝关节,MRI上定位STEA、CTEA、PCL、WL、AFA为骨性标志物,测量并比较3组CSA、PCA、CTA、WSA、WCA、AFSA、AFCA。结果 3组间CSA、WSA、WCA、AFSA、AFCA比较差异无统计学意义(P>0.05)。A组与B组、B组与C组的PCA、CTA比较差异无统计学意义(P>0.05),但A组与C组的PCA、CTA比较差异有统计学意义(P<0.05)。结论重度内翻畸形骨性关节炎影响股骨PCA及CTA,两者在C组有所减小;WSA、WCA不受骨性关节炎的影响,但角度变异较大,不能只用WL决定股骨假体的旋转;AFSA、AFCA不受骨性关节炎的影响,两者变异小(标准差为2.18°及2.38°),参照该轴放置股骨假体较可靠。     

Influence of the quality of tibial plateau alignment on the reproducibility of computer joint space measurement from Lyon schuss radiographic views of the knee in patients with knee osteoarthritis

RATIONALE: The quality of medial tibial plateau (MT-Plateau) alignment is one of the key elements for accuracy and sensitivity to change of knee radiography in knee osteoarthritis (OA). AIM: To evaluate the influence of the quality of the MT-Plateau alignment on the reproducibility of joint space width (JSW) measurement in knee radiographs. METHODS: One hundred and twenty-seven knee radiographs (99 OA), performed using a standardized radiographic procedure (Lyon schuss (LS) view). Evaluation of the quality of MT-Plateau alignment. Computerized measurement of the JSW, twice, 1-month apart, using a semi-automated and an automated method of measurement. Assessment of the reproducibility of repeated measurements: calculation of intra-observer coefficient of correlation, smallest detectable difference (SDD) and coefficient of variation (CV). RESULTS: MT-Plateau alignment was satisfactory in 99 radiographs (77.9%). Reproducibility was excellent in both satisfactory and non-satisfactory radiographs, irrespective of the method of measurement used. The automated measurement was more reproducible than the semi-automated one (CV 1.15% and 3.23%). SDD and CV were better in satisfactory than in non-satisfactory MT-Plateau aligned radiographs. CONCLUSION: These results confirm that computer measurement of the medial tibio-femoral JSW, from LS digitized radiographs, is highly reproducible, irrespective of the quality of the radiograph. However, the quality of the MT-Plateau alignment influences the reproducibility of JSW measurement. The automated measurement was more reproducible than the semi-automated one.     

The knee adduction moment during gait in subjects with knee osteoarthritis is more closely correlated with static alignment than radiographic disease severity, toe out angle and pain.

This study tested whether the peak external knee adduction moments during walking in subjects with knee osteoarthritis (OA) were correlated with the mechanical axis of the leg, radiographic measures of OA severity, toe out angle or clinical assessments of pain, stiffness or function. Gait analysis was performed on 62 subjects with knee OA and 49 asymptomatic control subjects (normal subjects). The subjects with OA walked with a greater than normal peak adduction moment during early stance (p = 0.027). In the OA group, the mechanical axis was the best single predictor of the peak adduction moment during both early and late stance (R = 0.74, p < 0.001). The radiographic measures of OA severity in the medial compartment were also predictive of both peak adduction moments (R = 0.43 to 0.48, p < 0.001) along with the sum of the WOMAC subscales (R = -0.33 to -0.31, p < 0.017). The toe out angle was predictive of the peak adduction moment only during late stance (R = -0.45, p < 0.001). Once mechanical axis was accounted for, other factors only increased the ability to predict the peak knee adduction moments by 10 18%. While the mechanical axis was indicative of the peak adduction moments, it only accounted for about 50% of its variation, emphasizing the need for a dynamic evaluation of the knee joint loading environment. Understanding which clinical measures of OA are most closely associated with the dynamic knee joint loads may ultimately result in a better understanding of the disease process and the development of therapeutic interventions.     

Association of serum carotenoids, retinol, and tocopherols with radiographic knee osteoarthritis: possible risk factors in rural Japanese inhabitants

Background

The consumption of antioxidant nutrients may influence the development and progression of osteoarthritis (OA). To determine the association between serum antioxidants and radiographic knee osteoarthritis, we undertook a cross-sectional investigation in a community-based study in Japan.

Methods

A total of 562 subjects (224 male, 338 female) ≥40 years of age were enrolled in the Comprehensive Health Examination Program (CHEP, Yakumo Study) from 2003 to 2005. Subjects were categorized to the OA group (n = 140) if either knee was graded as Kellgren-Lawrence (K-L) grade ≥2. The no-OA group was defined as showing radiographic findings of K-L 0 or 1 in either knee (n = 422). The serum levels of retinol, β-/γ-tocopherols, α-tocopherol, zeaxanthin/lutein, canthaxanthin, cryptoxanthin, lycopene, α-carotene, and β-carotene were measured by high-performance liquid chromatography. The values of these antioxidants were divided into tertiles, and a logistic regression analysis was performed to analyze the association between them and radiographic knee OA, adjusting for potential confounders.

Results

Logistic regression analysis showed that compared to the lowest tertile of β-/γ-tocopherols the adjusted odds ratio (OR) was 0.52 [95% confidence interval (CI) 0.29–0.93] in the highest tertile; it also indicated a linear trend across tertiles. Furthermore, the adjusted OR was significantly decreased only in the middle tertile of α-tocopherol (OR 0.51, 95% CI 0.29–0.90). We reevaluated any independent association for these tocopherols after adjustment by entering them into the model simultaneously. The significance of β-/γ-tocopherols was maintained. In contrast, no associations were found with any carotenoids or retinol.

Conclusions

High serum values of β-/γ-tocopherols were found to be significantly associated with a low OR for radiographic knee osteoarthritis. The decreasing risk with a high serum value of β-/γ-tocopherols may support the possible protective effects against knee OA.     

Changes in content and synthesis of collagen types and proteoglycans in osteoarthritis of the knee joint and comparison of quantitative analysis with Photoshop-based image analysis

Introduction  

The different cartilage layers vary in synthesis of proteoglycan and of the distinct types of collagen with the predominant collagen Type II with its associated collagens, e.g. types IX and XI, produced by normal chondrocytes. It was demonstrated that proteoglycan decreases in degenerative tissue and a switch from collagen type II to type I occurs. The aim of this study was to evaluate the correlation of real-time (RT)-PCR and Photoshop-based image analysis in detecting such lesions and find new aspects about their distribution.     

Influence of intra-operative parameters on postoperative early recovery of active knee flexion in posterior-stabilized total knee arthroplasty

Purpose

Active knee flexion is more important for daily activities than passive knee flexion. The hypothesis is that the intra-operative parameters such as osteotomized bone thickness and soft tissue balance affect the postoperative active flexion angle in total knee arthroplasty (TKA). Therefore, we evaluate the influence of intra-operative parameters on postoperative early recovery of active flexion after posterior-stabilized (PS) TKA.

Methods

The subjects were 45 osteoarthritic knees undergoing primary PS TKA with anterior-reference technique. Intra-operative soft tissue balance was measured using an offset type tensor, and each osteotomized bone thickness was also measured. Pre- and postoperative active knee flexion angles were measured using lateral radiographs. Liner regression analysis was used to determine the influence of these intra-operative parameters on postoperative active flexion angles or recovery of active flexion angles.

Results

Pre-operative flexion angle was positively correlated with postoperative flexion angle (R?=?0.52, P?=?0.0002). Postoperative flexion angle was negatively correlated with the osteotomized bone thickness of femoral medial posterior condyle (R?=??0.37, P?=?0.012), and femoral lateral posterior condyle (R?=??0.36, P?=?0.015). Recovery of flexion angle was slightly negatively correlated with gap difference calculated by subtracting joint gap at extension from that at flexion between osteotomized surfaces (R?=??0.30, P?=?0.046).

Conclusions

The osteotomized bone thickness of the femoral posterior condyle is a significant independent factor of postoperative flexion angles. This indicates that the restoration of the posterior condyle offset may lead to larger postoperative active flexion angles in PS TKA.     

Age‐associated increases in the size of the infrapatellar fat pad in knee osteoarthritis as measured by 3T MRI

Obesity, as a primary risk factor for osteoarthritis (OA), has been shown to alter joint loading, but may also result in metabolic changes characterized by chronic, low‐level inflammation due to increased circulating levels of adipose‐derived cytokines, or “adipokines.” The presence of the infrapatellar fat pad in the knee suggests that local changes in adipokine concentrations may influence knee OA. This study examined the hypotheses that the volume of the infrapatellar fat pad is correlated to the body mass index (BMI) of OA patients, and that fat pad volume is greater in subjects with OA. Fat pad volume was measured in sequential magnetic resonance (MR) images taken over one year in a cohort of 15 control and 15 knee OA subjects. No differences were observed in the fat pad volume between the two groups at baseline, 3, 6, or 12 months. In control subjects, no significant correlations were present between any parameters (age, BMI, weight, volume of fat pad at any time point). However, in the osteoarthritic group, fat pad volume was correlated with age at every time point. One possible explanation is that local factors related to knee OA may also induce enlargement of the fat pad with age. Alternatively, subjects who are prone to growth or enlargement of the fat pad may also be more prone to symptomatic OA. These findings provide intriguing preliminary data on the potential role of the infrapatellar fat pad in OA, although additional study is required to better understand the mechanisms of this relationship. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1149–1154, 2010     

腹腔镜气腹期间呼吸参数对部分CO_2重复吸入法监测的心输出量影响

目的通过部分CO2重复吸入法(RBCO)的实时连续监测,探讨腹腔镜气腹期间呼吸参数对心输出量(CO)的影响。方法选择择期妇科腹腔镜手术患者80例,根据VT与I∶E的不同组合随机分为四组,A组:VT8ml/kg,I∶E 1∶1;B组:VT8ml/kg,I∶E 1∶2;C组:VT10ml/kg,I∶E 1∶1;D组:VT10ml/kg,I∶E 1∶2。记录气腹前(T0)、气腹后3min(T1)、气腹后6min(T2)、气腹后9min(T3)、气腹后12min(T4)、气腹后15min(T5)、气腹结束前6min(T6)、气腹结束前3min(T7)、气腹结束(T8)的CO、PETCO2、肺泡通气量(MValv)、分钟通气量(MV)、气道峰压(PIP)、平均气道压力(MAP)、二氧化碳清除率(VCO2)、动态顺应性(Cdyn)、气道阻力(Raw)以及HR、SBP和DBP。采用多元线性回归分析以上呼吸参数对RBCO监测的CO影响。结果多元线性回归分析显示:CO随PETCO2和VCO2的增大而增大,β值分别为0.390,0.266(P0.01),随MAP和I∶E的增大而减小,β值分别为-0.287和-0.172(P0.01)。结论通过RBCO监测,可以发现腹腔镜气腹期间呼吸参数对CO的影响,其中CO随PETCO2或VCO2的增大而增大,随MAP或I∶E的增大而减小。     

不同浓度木瓜蛋白酶建立兔膝骨关节炎模型的比较研究

目的:比较不同浓度木瓜蛋白酶建立的兔膝骨关节炎模型,为研究骨关节炎病理及诊疗方法提供数据支持。方法:将60只新西兰大耳白兔随机分为4组,分别在1、3、5d右膝关节腔注射2%(低剂量组)、5%(中剂量组)、10%(高剂量组)(w/v)木瓜蛋白酶和0.03mol/L的L-半胱氨酸混合溶液0.1ml/kg(实验组),以及等量生理盐水(对照组)。整个实验过程观察兔状态并记录体重和膝关节宽度。首次注射后第2、4、6周将兔分批处死,取股骨髁、胫骨平台及滑膜做大体及组织病理学观察,并进行评分。结果:实验组均出现关节宽度增大、关节软骨变薄、基质分解破坏、滑膜增生等炎症及退行性改变,严重程度随浓度增高而增高,也随时间延长而发展;对照组无上述改变,二者比较差异有统计学意义。结论:兔膝骨关节腔注射2%、5%、10%木瓜蛋白酶和0.03mol/LL-半胱氨酸混合溶液0.1ml/kg可制备不同严重程度的骨关节炎模型,周期短,可重复且成功率高。