Measurement Of Joint Space Width Research Articles

In normal knees, joint space width (JSW) is correlated with the intermargin distance (IMD), a measure of medial tibial plateau alignment. Variations in IMD explain variability in JSW in serial radiographs

ObjectiveTo ascertain the importance of alignment of the medial tibial plateau (MTP), as determined by the distance between the anterior and posterior margins of the plateau (intermargin distance [IMD]), for measurements of joint space width (JSW) in radiographs of normal knees. MethodsJSW and IMD were measured in paired baseline and 12-month knee films of 122 subjects from the osteoarthritis initiative (OAI). Relationships between JSW and IMD, and between the variation in JSW and variation in IMD, were evaluated. ResultsIn cross-sectional analysis, a non-linear relationship existed between JSW and the concurrent IMD. With poor MTP alignment (IMD>1.7mm), a 1.0-mm increase in IMD resulted in a 0.16-mm (95%CI: 0.11–0.21) increase in JSW (P<0.0001). In a longitudinal analysis, the effect of IMD variation on variation in JSW was also highly significant (P<0.0001). A variation of 1mm between IMDBaseline and IMD12month was associated with a 0.10-mm (95% CI: 0.06–0.13) variation in JSW, with variations in JSW and IMD occurring in the same direction. An IMD variation less than or equal to 1.0mm was determined to be acceptable for accurate evaluation of JSW in serial radiographs. ConclusionThe error in measurement of JSW caused by variation in IMD in serial radiographs of normal knees can be as large, or larger, than the mean rate of 12-month joint space narrowing (JSN) in OA knees. MTP alignment and replication of alignment in serial knee films are required for accurate determination of JSN in OA knee.

Influence of variation in semiflexed knee positioning during image acquisition on separate quantitative radiographic parameters of osteoarthritis, measured by Knee Images Digital Analysis

The clinical application of quantitative measurement of separate radiographic parameters of knee osteoarthritis (OA) might be hampered by a lack of reproducible semiflexed joint positioning during acquisition of radiographs. The influence of systematic variations in knee positioning on measurement of separate quantitative radiographic parameters was studied. Five components of knee position during radiographic acquisition (beam height, lower and upper leg extension, internal rotation, and lateral shift) were systematically varied within a clinically relevant range, using three cadaver legs. The influence of these variations on the measurement of the separate quantitative radiographic parameters by Knee Images Digital Analysis (KIDA) was evaluated. Significant changes were validated invivo. Changes were compared with differences during 2-year follow-up in a radiographic progression cohort of early OA. Systematic variation in upper and lower leg extension induced changes in the measurement of joint space width (JSW). Lower leg extension also influenced osteophyte area and eminence height measurement. Also bone density measurement was influenced by variation in all five position components. Variations were of clinical relevance compared with 2-year differences in knees with radiographic progression, and were confirmed invivo. Variations in semiflexed knee positioning, which are considered to occur easily during image acquisition in trials and clinical practice despite standardization, are of significant influence on the quantitative measurement of most separate radiographic parameters of OA using KIDA. The additional value of quantitative measurement might improve significantly by better standardization during radiographic acquisition; with radiography still being the gold standard for structure-modification in OA.

Quantification of baseline hand joint space width does not differentiate individuals who develop incident knee osteoarthritis from controls: data from the osteoarthritis initiative

Purpose: Previous studies that used semi-quantitative scoring of hand radiographs suggest that hand osteoarthritis (OA) puts a person at risk for knee OA. One possible mechanism to explain a relationship between hand and knee OA is a systemic cartilage loss. Therefore, we used a quantitative method to measure hand joint space width (JSW), an imaging marker of cartilage loss, to test whether individuals that develop incident knee OA have less finger joint cartilage. Methods: Participants of the OAI were included in this case-control study if they had knee radiographs at the baseline and 48-month visit as well as quantitative and semi-quantitative radiographic knee readings (as of October 2011). Cases were defined as individuals with an incident knee osteophyte (baseline OARSI osteophyte score < 2 and 48-month OARSI osteophyte score 2). Controls were individuals with no incident knee osteophyte (baseline and 48-month OARSI osteophyte scores < 2). If a participant had a case and control knee, then the control knee was excluded. If the participant had two case knees or two control knees, then the right knee was selected. 276 knee-, cohort-, age-, gender-, and body mass index-matched participants met this criteria. Two readers used a semi-automated, custom software to delineate the joint margins metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints of digits 2 to 5 on the dominant hand. The software divided each joint into 5 regions to derive a region-specific JSW measurement (JSW1 to JSW5; inter-tester ICC [2,1 model] 1⁄4 0.82 to 0.92; see Figure). Due to anatomical considerations the outermost regions (JSW1 and JSW5) of the MCP joints could not be reliably replicated and were excluded from calculations. Mean MCP JSW, mean PIP JSW, and mean DIP JSW were calculated by averaging the joint JSW measurements across regions within joint and across fingers. Mean hand JSW was averaged across all regions, joints, and fingers to develop a composite hand measurement. Four paired sample t-tests (p < 0.05) were performed to compare the four mean JSW measurements between cases and controls. Results: Of the 276 participants, 121 matched case-control pairs had readable hand radiographs. Case participants were 62.5 8.6 years of age, had a body mass index of 29.7 4.1 kg/m, and 8 (6.67%) were left handed. Control participants were 62.5 8.4 years of age, had a body mass index of 29.4 5.0 kg/m, and 5 (4.13%) were left handed. Both groups were 68.6% female, included 65 (54%) right knees, and 63 (52%) participants from the Incidence cohort. Paired sample t-tests revealed no significant differences in all mean JSW measurements between the case and control groups (see Table). Conclusions: We found that baseline mean hand JSW is not significantly different among those who develop a definite knee osteophyte over 48 months and those who do not. Our results indicate that systemic loss of cartilage is not an explanation of the relationship of hand and knee OA. Ă

A new method to measure anatomic knee alignment: a tool for large studies of OA?

Purpose: Knee malalignment alters load distribution across the articular surface and is a potent predictor of knee osteoarthritis (OA) progression. The hip-knee-ankle angle (HKA) provides the most direct measurement of biomechanical leg alignment, but requires a long-limb radiograph. The femorotibial alignment angle (FTA) of the knee joint is an indirect measure of mechanical alignment but can be performed using a standard knee radiograph. Traditional methods of measuring the FTA require a reader to identify landmarks in the tibial spines, which can be difficult and unreliable for abnormally positioned knee images. We have developed and validated a new software method to rapidly determine FTA that may expedite the measurement of knee radiographs from large studies such as the Osteoarthritis Initiative (OAI). Methods: The method is based on the coordinate system developed for location specific joint space width (JSW) measurements, previously used to demonstrate that quantitative radiographic measures are comparable with MRI for detecting OA progression. The coordinate system directly determines the orientation of the femur (Figure 1) and also defines a central point of the knee. The axis is perpendicular to a line tangent to the base of the femoral condyles, and centered between the outer aspects of the condyles. Four points on margins of the tibial shaft define the axis of the tibia. Two points are marked 10 cm from the center point and two are placed 1 cm from the base of the tibial plateau. The study used subjects from the Progression Cohort of the Osteoarthritis Initiative (OAI) (OAI Datasets 0.1.1, 0.B.1, and 1.B.1) where HKA measurements were available from the OAI. We excluded images where the center of the knee was less than 10 cm from the lower edge of the image, leaving 266 total knees from 142 subjects for the final analysis. The study used two readers. Reader 1 read the data twice with the new procedure and two times using a traditional method. Reader 2 performed a single reading with each of the two methods. Linear regression analysis was used to assess reader reproducibility, and correlation with the HKA measurement. Results: Table 1 provides the results comparing the two methods. The new method of measuring FTA was related to HKA by FTA = 0.52HKA - 4.7 degrees. The traditional method was related to HKA by FTA = 0.65HKA + 1.5 degrees. The additional reader time was less than 30 seconds per image once an image had been processed for the location-specific JSW measurement. Conclusions: We found improved inter and intra reader reproducibility compared with the traditional method and higher correlation with the HKA. With the new method, very little difference was observed between the inter and intra reader precision suggesting a robust technique. The fast reader time implies that assessment of large numbers of subjects is feasible. Furthermore, the method does not require landmarks placed in the tibial spines; it can be performed by a relatively unskilled reader whose task is limited to marking points on the shaft of the tibia and the femoral condyles. A limitation of the method is that it relies on the coordinate system set up for location specific JSW; additional time is necessary if this step has not already been performed. However, setting up the coordinate system is substantially automated and could be performed independent of measuring JSW if necessary. In summary, we have documented a new technique that can provide a precise, accurate, rapid and reproducible measurement of radiographic knee anatomic alignment, with significant implications for efficiency and cost-effectiveness for very large studies of knee OA.

Effects of training intervention on quadriceps heads in untrained middle-aged women

Effects of training intervention on quadriceps heads in untrained middle-aged women

Determination of Cartilage Volume Using MRI in Patients with Knee Osteoarthritis: Efficacy Study of 25 Milligrams of Sodium Hyaluronate (2.5 Ml) Versus Placebo

Background: Osteoarthritis (OA) of the knee is prevalent and associated with both pain and functional disability. Visco-supplementation is an intra-articular therapeutic modality for the treatment of knee OA, based on the physiologic importance of hyaluronan in synovial joints. The therapeutic goal is to restore the viscoelasticity of synovial hyaluronan, decrease pain, improve mobility and restore the natural protective functions of hyaluronan in the joint radiography is currently the most widely used modality for assessing damage in OA: this technique allows the measurement of joint space width (JSW) the appropriate primary endpoint for demonstration of efficacy. There are, however, questions regarding its validity and reliability. Magnetic resonance imaging (MRI) with its superior soft tissue contrast is the best technique available for assessment of normal articular cartilage and cartilage volume. Therefore, this study aimed to evaluate the short-term benefit of intra-articular injection of hyaluronic acid (GoOn®) for protecting the articular by using MRI in patient with OA knee. Patients and Methods: This was a phase III double-blinded (i.e., both the patients and MRI examiners), randomized, controlled trial of 60 patients with mild to moderate knee OA, diagnosed according to both clinical signs and X-ray. All of the patients received MRIs (1.5 T) of the affected knee(s) at visit 0 and 6 months after the first injection. The patients received either an intra-articular injection into the affected knee weekly for 5 weeks of HA (GoOn®) or a placebo. Blinded examiners used the visual analog scale (VAS) and the WOMAC score to do weekly and monthly assessments for 6 months. The engineer used Mimics 10.01 to transform the MRI scanner data into 3D images of the articular cartilage for measuring CV, which was also blinded to the treatments. Results: Subjects averaged 59.5 years of age (range, 46 to 84). During the enrollment phase, only female farmers attended came. Four patients in the placebo group and one in the GoOn® group refused to undergo the second MRI. The mean body weight and height was 64.20 ± 10.25 kg and 1.53 ± 0.057 m, respectively. The respective baseline VAS and WOMAC score was 6.40 ± 1.64 and 51.65 ± 13.3. Forty-four patients were KL grade 2 and 16 were grade 3. The mean total CV at baseline in the GoOn® and placebo groups was 14.7 ± 3.5 ml and 15.5 ± 3.9 ml, respectively. There was no significant difference in the mean total CV after 6 months in either group (p>0.05) except at the femorotibial junction of the GoOn® group was increase CV more than the placebo group (p<0.05). The mean difference in the total WOMAC score and all three subscales in the GoOn® vs. the placebo groups were statistically significant (p<0.05). The difference in mean VAS between both groups was not statistically significant. No adverse events were reported. Conclusion: GoOn® was an effective symptomatic treatment in mild to moderately painful OA knees according to the WOMAC score. In the short-term six-month period, there was not any change in the total cartilage volume except at the femoro-tibial junction.

Reproducibility and influence of hand rotation on computer-aided joint space analysis

ObjectivesComputer-aided joint space analysis (CAJSA) is a recently developed, semi-automated tool to aid in the measurement of joint space margins based on hand radiographs. The objective of this study is to verify the potential effect of hand rotation during X-ray imaging on the measurement of joint space width using CAJSA and to evaluate the reproducibility of the CAJSA technique in healthy subjects and in patients with rheumatoid arthritis. MethodsAll joint space distance (JSD) measurements were performed using CAJSA-technology at the metacarpophalangeal articulation based on conventional and digital hand radiographs. ResultsI. Hand rotation showed an effect on the reproducibility with CV ranging between 0.39% (angulation 1°) and 1.66% (angulation 19°). II. Regarding the overall reproducibility of the CAJSA method, the intra-radiograph reproducibility of JSD was calculated with CV=0.54% for conventional images and CV=0.38% for digital images. The inter-radiograph reproducibility error was observed with CV=0.66% (conventional images) and CV=0.63% (digital images). III. The study revealed a reproducibility for CAJSA measurements in RA ranging between 0.37% (JSD-MCP ring finger; van der Heijde-modification of the Sharp method Score 1) to 1.37% (JSD-MCP index finger; van der Heijde-modification of the Sharp method Score 3). ConclusionCAJSA measures JSD at the metacarpophalangeal articulation with high reproducibility in healthy subjects and in patients with differing stages of rheumatoid arthritis. Additional findings show that hand rotation during X-ray imaging has an impact on the CAJSA measurements; thus avoiding acquisition of hand radiographs with a rotation error of more than 15 degrees can be recommended.

Development of a joint space width measurement method based on radiographic hand images

This study presents a novel algorithm to measure joint space widths (JSWs) in patients with rheumatoid arthritis (RA) using radiographic hand images. Radiographic images were first preprocessed, and then phalangeal regions corresponding to the bone structures of each finger were extracted using step-wedge functions. Phalangeal branch paths were also extracted. Each of the five extracted phalangeal branch paths matched the bone structures of each finger exactly and ran through the center of each finger. The algorithm automatically detected 14 joints, which were identified as sharp changes in gray scale intensity along phalangeal branch paths through the profile plot. The regions of interest corresponding to the 14 joints were subsequently extracted. A total of 35 radiographic images from three groups were tested. The performance of our algorithm was evaluated by measuring joint location percentage errors and mean JSWs for three joints in the phalanges. The algorithm correctly detected 94.69% of total joints and had a low detection rate in RA patients with severe deformities or ankylosis. The mean JSW in the control group was significantly greater than that in the RA group ( p<0.05). In contrast, the standard deviation of JSW in the control group was lower than that in the RA groups ( p<0.005). Control and seropositive RA groups showed significant symmetry in JSW values.

Validity of joint space width measurements in hand osteoarthritis

To investigate the validity of joint space width (JSW) measurements in millimeters (mm) in hand osteoarthritis (OA) patients by comparison to controls, grading of joint space narrowing (JSN), and clinical features. Hand radiographs of 235 hand OA patients (mean age 65 years, 83% women) and 471 controls were used. JSW was measured with semi-automated image analysis software in the distal, proximal interphalangeal and metacarpal joints (DIPJs, PIPJs and MCPJs). JSN (grade 0-3) was assessed using the osteoarthritis research society international (OARSI) atlas. Associations between the two methods and clinical determinants (presence of pain, nodes and/or erosions, decreased mobility) were assessed using Generalized Estimating Equations with adjustments for age, sex, body mass index (BMI) and mean width of proximal phalanx. JSW was measured in 5631 joints with a mean JSW of 0.98 mm (standard deviation (SD) 0.21), being the smallest for DIPJs (0.70 (SD 0.25)) and largest for MCPJs (1.40 (SD 0.25)). The JSN=0 group had a mean JSW of 1.28 mm (SD 0.34), the JSN=3 group 0.17 mm (SD 0.23). Controls had larger JSW than hand OA patients (P-value<0.001). In hand OA, females had smaller JSW than men (β -0.08, (95% confidence interval (95% CI) -0.15 to -0.01)) and lower JSW was associated with the presence of pain, nodes, erosions and decreased mobility (adjusted β -0.21 (95% CI -0.27, -0.16), -0.37 (-0.40, -0.34), -0.61 (-0.68, -0.54) and -0.46 (-0.68, -0.24) respectively). These associations were similar for JSN in grades. In hand OA the quantitative JSW measurement is a valid method to measure joint space and shows a good relation with clinical features.

Validity and responsiveness of radiographic joint space width metric measurement in hip osteoarthritis: a systematic review

To perform a systematic review of the literature on the concurrent validity, predictive validity and responsiveness of radiographic metric measurement of femoro-acetabular joint space width (JSW) in hip osteoarthritis (OA). studies reporting any data on (1) JSW on X-rays in hip OA patients and (2) concurrent validity (correlations with clinical symptoms), predictive validity (correlations with future symptomatic state, joint space loss or joint replacement), and/or responsiveness (JSW change over time evaluated using the standardized response mean (SRM)). Medline PUBMED and Embase databases. Random-effects models were constructed to obtain pooled SRMs. Of 448 articles, 79 met the abstract inclusion criteria and were read for further screening. Of these, 15 reported measures of validity and 11 reported measures of responsiveness. Concurrent validity: Five studies suggested an association between JSW and symptoms in the general population. Two evaluated the correlations between JSW and symptoms in hip OA patients, with conflicting results. Five demonstrated that JSW is predictive of future hip joint replacement. Responsiveness was moderate (SRM=0.66; 95% confidential interval (95%CI): 0.41, 0.91), but tended to be lower in randomized clinical trials than in cohort studies (0.35 vs 0.83), using an intention to treat rather than a completer analysis (0.30 vs 0.80), and using manual rather than computer-based measurement (0.47 vs 1.12). There is evidence of a weak association between JSW and symptoms, of predictive validity for subsequent joint replacement, and of moderate responsiveness of metric measurement of JSW.

Responsiveness to change and reliability of measurement of radiographic joint space width in osteoarthritis of the knee: a systematic review

The goal of this systematic review was to report the responsiveness to change and reliability of conventional radiographic joint space width (JSW) measurement. We searched the PubMed and Embase databases using the following search criteria: [osteoarthritis (OA) (MeSH)] AND (knee) AND (X-ray OR radiography OR diagnostic imaging OR radiology OR disease progression) AND (joint space OR JSW or disease progression). We assessed responsiveness by calculating the standardized response mean (SRM). We assessed reliability using intra- and inter-reader intra-class correlation (ICC) and coefficient of variation (CV). Random-effects models were used to pool results from multiple studies. Results were stratified by study duration, design, techniques of obtaining radiographs, and measurement method. We identified 998 articles using the search terms. Of these, 32 articles (43 estimates) reported data on responsiveness of JSW measurement and 24 (50 estimates) articles reported data on measures of reliability. The overall pooled SRM was 0.33 [95% confidence interval (CI): 0.26, 0.41]. Responsiveness of change in JSW measurement was improved substantially in studies of greater than 2 years duration (0.57). Further stratifying this result in studies of greater than 2 years duration, radiographs obtained with the knee in a flexed position yielded an SRM of 0.71. Pooled intra-reader ICC was estimated at 0.97 (95% CI: 0.92, 1.00) and the intra-reader CV estimated at 3.0 (95% CI: 2.0, 4.0). Pooled inter-reader ICC was estimated at 0.93 (95% CI: 0.86, 0.99) and the inter-reader CV estimated at 3.4% (95% CI: 1.3%, 5.5%). Measurement of JSW obtained from radiographs in persons with knee is reliable. These data will be useful to clinicians who are planning RCTs where the change in minimum JSW is the outcome of interest.

Summary and recommendations of the OARSI FDA osteoarthritis Assessment of Structural Change Working Group

The Osteoarthritis Research Society International initiated a number of working groups to address a call from the US Food and Drug Administration (FDA) on updating draft guidance on conduct of osteoarthritis (OA) clinical trials. The development of disease-modifying osteoarthritis drugs (DMOADs) remains challenging. The Assessment of Structural Change (ASC) Working Group aimed to provide a state-of-the-art critical update on imaging tools for OA clinical trials. The Group focussed on the performance metrics of conventional radiographs (CR) and magnetic resonance imaging (MRI), performing systematic literature reviews for these modalities. After acquiring these reviews, summary and research recommendations were developed through a consensus process. For CR, there is some evidence for construct and predictive validity, with good evidence for reliability and responsiveness of metric measurement of joint space width (JSW). Trials off at least 1 and probably 2 years duration will be required. Although there is much less evidence for hip JSW, it may provide greater responsiveness than knee JSW. For MRI cartilage morphometry in knee OA, there is some evidence for construct and predictive validity, with good evidence for reliability and responsiveness. The responsiveness of semi-quantitative MRI assessment of cartilage morphology, bone marrow lesions and synovitis was also good in knee OA. Radiographic JSW is still a recommended option for trials of structure modification, with the understanding that the construct represents a number of pathologies and trial duration may be long. MRI is now recommended for clinical trials in terms of cartilage morphology assessment. It is important to study all the joint tissues of the OA joint and the literature is growing on MRI quantification (and its responsiveness) of non-cartilage features. The research recommendations provided will focus researchers on important issues such as determining how structural change within the relatively short duration of a trial reflects long-term change in patient-centred outcomes.

Automatic radiographic quantification of hand osteoarthritis; accuracy and sensitivity to change in joint space width in a phantom and cadaver study.

ObjectiveTo validate a newly developed quantification method that automatically detects and quantifies the joint space width (JSW) in hand radiographs. Repeatability, accuracy and sensitivity to changes in JSW were determined. The influence of joint location and joint shape on the measurements was tested.MethodsA mechanical micrometer set-up was developed to define and adjust the true JSW in an acrylic phantom joint and in human cadaver-derived phalangeal joints. Radiographic measurements of the JSW were compared to the true JSW. Repeatability, systematic error (accuracy) and sensitivity (defined as the smallest detectable difference (SDD)) were determined. The influence of joint position on the JSW measurement was assessed by varying the location of the acrylic phantom on the X-ray detector with respect to the X-ray beam and the influence of joint shape was determined by using morphologically different human cadaver joints.ResultsThe mean systematic error was 0.052 mm in the phantom joint and 0.210 mm in the cadaver experiment. In the phantom experiments, the repeatability was high (SDD = 0.028 mm), but differed slightly between joint locations (p = 0.046), and a change in JSW of 0.037 mm could be detected. Dependent of the joint shape in the cadaver hand, a change in JSW between 0.018 and 0.047 mm could be detected.ConclusionsThe automatic quantification method is sensitive to small changes in JSW. Considering the published data of JSW decline in the normal and osteoarthritic population, the first signs of OA progression with this method can be detected within 1 or 2 years.

Patient repositioning reproducibility of joint space width measurements on hand radiographs

Computer-based methods to measure radiographic joint space width (JSW) have the potential to improve the longitudinal assessment of rheumatoid arthritis (RA). The purpose of this report was to measure the long-term patient repositioning reproducibility of software-measured radiographic JSW. Patients underwent baseline and followup hand radiography examinations with a followup time of ≤3 years. To eliminate any JSW change due to real disease progression, the evaluation was performed on "unaffected" joints, defined as having JSW and erosion Sharp scores of 0 at both baseline and followup. The root mean square SD (RMSSD) and coefficient of variation (CV) were used as the reproducibility metrics. The RMSSD was 0.14 mm (CV 10.5%) for all joints, 0.18 mm (CV 10.9%) for the metacarpophalangeal (MCP) joints, and 0.08 mm (CV 8.3%) for the proximal interphalangeal (PIP) joints. The distribution of JSW change was asymmetric, suggesting that narrowing due to RA progression occurred for several joints. A second analysis was performed, excluding joints where the loss of JSW was greater than 3 SDs. For this analysis, the RMSSD was 0.10 mm (CV 7.5%) for all joints, 0.12 mm (CV 7.3%) for the MCP joints, and 0.07 mm (CV 7.1%) for the PIP joints. Repositioning reproducibility is very good but is likely to be a dominating factor compared to reader and software reproducibility. Additionally, further evidence is given that a software method is able to detect changes in some joints for which the Sharp score is insensitive.

Influence of the experience of the reader on reliability of joint space width measurement. A cross-sectional multiple reading study in hip osteoarthritis

Objectives The objectives were to evaluate improvement in reliability of joint space width (JSW) measurements, according to the previous experience of the readers in hip osteoarthritis (OA). Methods Fifty radiographs in hip OA patients from a randomized controlled trial (ECHODIAH) were read 12 times by two readers with different levels of experience in radiographic interpretation. Intra-reader reliability and inter-reader reliability were assessed through calculation of the smallest detectable difference (SDD) and the intra-class correlation coefficient (ICC). Results Intra-reader reliability: for the experienced reader, no significant change in SDD was observed with repeated JSW measurements. For the junior reader, the SDD decreased significantly from 0.90 mm to 0.65 mm ( P = 0.002). A plateau of SDD was reached after reading 200 to 300 radiographs, with a value close to the mean SDD of the experienced reader (0.67 mm). ICCs were high (> 0.88) for both the senior and the junior readers. Inter-reader reliability: no improvement in inter-reader reliability was noted with repeated measurements of JSW (SDD = 0.81 mm). However, no additional training sessions were performed. ICCs were high (> 0.85). Conclusion This study indicated for the first time a learning curve in analyzing JSW in hip OA for an inexperienced reader. After analyzing 200 to 300 radiographs, the junior reader reached an intra-reader reliability similar to the experienced reader. Moreover, the information brought by the ICC was not sufficient, suggesting that the SDD should be systematically reported in studies evaluating OA radiographic progression, on top of the ICC, to help in interpreting the JSW reliability.

Influence of blinding sequence of radiographs on the reproducibility and sensitivity to change of joint space width measurement in knee osteoarthritis

To investigate whether knowledge of the sequence of radiographs impacts inter- and intraobserver reproducibility and sensitivity to change for measuring joint space width (JSW) in patients with knee osteoarthritis (OA). A cohort of 70 postmenopausal women with radiologic knee OA was assessed through the measurement of knee radiographs acquired in the semiflexed posteroanterior view, using a positioning frame and fluoroscopy, at baseline and 48 months later. Paired readings of radiographs were made using landmarks at baseline by 2 independent observers unblinded to sequence and blinded to sequence. Intra- and interobserver reproducibility was assessed on JSW measurements at baseline and 4 years later and on the longitudinal difference (joint space narrowing [JSN]), using intraclass correlation coefficient (ICC) and Bland and Altman methods. The sensitivity to change was assessed through standardized response means (SRMs). For JSW and JSN and with both methods, ICCs were high for the intra- and interobserver reproducibility (0.90-0.99 for JSW and 0.77-0.89 for JSN). For the Bland-Altman method, the mean difference was close to 0, with no bias for both observers and methods. The SRMs ranged from 0.38 to 0.48. All of the results were numerically in favor of measuring with knowledge of time sequence, but without a statistically significant difference between the methods. Intra- and interobserver reproducibility was high with or without blinding of the radiograph sequence. Reading with knowledge of time sequence using baseline landmarks tended to improve sensitivity. Therefore, in longitudinal studies of OA radiographs can be read unblinded to sequence.

Sample size for prospective studies of hip joint space width narrowing in osteoarthritis by the use of radiographs

To determine the number of participants required in controlled clinical trials investigating the progression of osteoarthritis (OA) of the hip as evaluated by the joint space width (JSW) on radiographs and to evaluate the reproducibility of the JSW measurement methods. Anteroposterior radiographs of hip were taken from 13 healthy volunteers and from 18 subjects with radiographic hip OA. The reproducibility of the JSW was determined from four segments using digital caliper measurements performed on film radiographs and using semiautomatic computerized image analysis of digitized images. Pearson correlation coefficient, coefficient of variability [CV (%)], and sample size values were calculated. It was found that 20 was a typical number of patients for a sufficiently powered study. The highest sample size was found in subjects with OA in the lateral segment. The reproducibility of the semiautomatic computerized method was not significantly better than the digital caliper method. The number of study subjects required to detect a significant joint space narrowing in follow-up studies is influenced by the baseline hip joint OA severity. The JSW measurements with computerized image analysis did not improve the reproducibility and thus performing JSW measurements with a digital caliper is acceptable.

Comparison of radiographic joint space width with magnetic resonance imaging cartilage morphometry: Analysis of longitudinal data from the osteoarthritis initiative

Magnetic resonance imaging (MRI) and radiography are established imaging modalities for the assessment of knee osteoarthritis (OA). The objective of our study was to compare the responsiveness of radiographic joint space width (JSW) with MRI-derived measures of cartilage morphometry for OA progression in participants from the Osteoarthritis Initiative (OAI). This study examined the baseline and 12-month visits of a subset of 150 subjects from the OAI. Measurement of radiographic JSW was facilitated by the use of automated software that delineated the femoral and tibial margins of the joint. Measures of medial compartment minimum JSW and JSW at fixed locations were compared with cartilage morphometry measures derived from MRI. The results were stratified by Kellgren/Lawrence (K/L) scale grade and by tibiofemoral anatomic axis angle. In order to examine the relative responsiveness of various techniques, we calculated the standardized response mean (SRM) between the 2 visits. The SRM for radiographic JSW measured at the optimal location was -0.32 compared with -0.39 for the most responsive MRI measure. For the subgroup with a K/L scale grade of 2 or 3, the most responsive SRM values were -0.34 for radiographic JSW and -0.42 for MRI. Our study demonstrates that new measures using a software analysis of digital knee radiographic images are comparable with MRI in detecting OA progression, and potentially superior when considering the cost-effectiveness of the 2 imaging modalities.

Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC), after slipped capital femoral epiphysis

Objective The aim of this study was to assess the glycosaminoglycan (GAG) content in hip joint cartilage in mature hips with a history of slipped capital femoral epiphysis (SCFE) using delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). Methods 28 young-adult subjects (32 hips) with a mean age of 23.8 ± 4.0 years (range: 18.1–30.5 years) who were treated for mild or moderate SCFE in adolescence were included into the study. Hip function and clinical symptoms were evaluated with the Harris hip score (HHS) system at the time of MRI. Plain radiographic evaluation included Tonnis grading, measurement of the minimal joint space width (JSW) and alpha-angle measurement. The alpha-angle values were used to classify three sub-groups: group 1 = subjects with normal femoral head–neck offset (alpha-angle <50°), group 2 = subjects with mild offset decrease (alpha-angle 50°–60°), and group 3 = subjects with severe offset decrease (alpha-angle >60°). Results There was statistically significant difference noted for the T1 Gd values, lateral and central, between group 1 and group 3 ( p-values = 0.038 and 0.041). The T1 Gd values measured within the lateral portion were slightly lower compared with the T1 Gd values measured within the central portion that was at a statistically significance level ( p-value <0.001). HHS, Tonnis grades and JSW revealed no statistically significant difference. Conclusion By using dGEMRIC in the mid-term follow-up of SCFE we were able to reveal degenerative changes even in the absence of joint space narrowing that seem to be related to the degree of offset pathology. The dGEMRIC technique may be a potential diagnostic modality in the follow-up evaluation of SCFE.

Short-term repeatability of joint space width measurements using a magnetic resonance imaging compatible knee positioning device

The purpose of this study was to evaluate a magnetic resonance imaging (MRI) compatible knee positioning device to aid in minimizing intratechnologist and intertechnologist differences of minimum joint space width (JSW) measurements. Five subjects were scanned by two separate technologists, with and without an MRI-compatible positioning device. A semi-automated program calculated the minimum JSW of the tibiofemoral and patellofemoral joints. The scan-to-scan repeatability was evaluated from measurements between serial scans without subject repositioning, and the intratechnologist and intertechnologist repeatabilities were evaluated when the subject was removed from the magnet and repositioned by an individual technologist. The root mean square (RMS) error of the JSW measurements was also calculated. All measures of scan-to-scan repeatability and intratechnologist repeatability were unchanged with the MRI-compatible positioning device. The intertechnologist repeatability decreased from 0.70 to 0.42 mm, and the RMS error was significantly reduced (P = 0.0006) from 0.26 to 0.15 mm for the tibiofemoral joint. The variability of patellofemoral JSW measurements increased when using the positioning device; however, the increases were not statistically significant. The intertechnologist repeatability increased from 1.55 to 1.79 mm, and the RMS error increased from 0.58 to 0.73 mm. The MRI-compatible positioning device was successful at reducing JSW measurement variability at the tibiofemoral joint. The increase in measurement variability at the patellofemoral joint may be due to local incongruities of the articular surfaces. An MRI-compatible positioning device may be beneficial for quantitative longitudinal studies evaluating knee joint health.