Anteroposterior radiographs of the osteoarthritic knee

The effect of erect abdomen radiography on absorbed doses to internal organs and tissues: A clinical study

BACKGROUND

As low as reasonably achievable principles (ALARA) should be applied during all X-ray examinations. In some institutions, an acute abdomen series includes both erect and supine radiography. The purpose of the study was to evaluate the effect of an erect position on absorbed dose to internal abdominal organs when compared with the supine position.

MATERIAL AND METHODS

A prospective study was undertaken where 81 patients were imaged in both supine and erect positions. The PCXMC Monte Carlo software was used to estimate individual organ doses using dose area product (DAP). Absorbed doses were calculated for the large intestines, active bone marrow, liver, lungs, small intestine, stomach, gallbladder, breasts, uterus, ovaries, urinary bladder, kidneys, testicles, and prostate.

RESULTS

The results showed a significant increase of absorbed dose by 1.4% when moving from a supine to an erect position. The testes were found to be the organs most affected by the erect position and then the urinary bladder.

CONCLUSIONS

According to the study's findings, using the erect position during abdominal radiography increases the radiation dose for all of the selected organs compared to using a supine position. Therefore, it is advised that the use of erect abdomen radiography be restricted to certain circumstances.

Imaging in Osteoarthritis

Osteoarthritis (OA) is the most frequent form of arthritis with major implications on both individual and public health care levels. The field of joint imaging, and particularly magnetic resonance imaging (MRI), has evolved rapidly due to the application of technical advances to the field of clinical research. This narrative review will provide an introduction to the different aspects of OA imaging aimed at an audience of scientists, clinicians, students, industry employees, and others who are interested in OA but who do not necessarily focus on OA. The current role of radiography and recent advances in measuring joint space width will be discussed. The status of cartilage morphology assessment and evaluation of cartilage biochemical composition will be presented. Advances in quantitative three-dimensional morphologic cartilage assessment and semi-quantitative whole-organ assessment of OA will be reviewed. Although MRI has evolved as the most important imaging method used in OA research, other modalities such as ultrasound, computed tomography, and metabolic imaging play a complementary role and will also be discussed.

Correlation of tibiofemoral joint-space width with the clinico-radiological scoring of knee osteoarthritis – a comparison between anteroposterior and lyon-schuss radiographic views

Background

The degree of joint space narrowing measured on radiographs provide a reliable estimate of the extent and severity of Osteoarthritis (OA) of the knee. While the standing antero-posterior (AP) view radiographs have been used traditionally, recent studies suggest that the Lyon-Schuss (LS) view is able to detect early OA changes better. The present study was, therefore, conducted to make an objective comparison between the two views with respect to their corelation with the patient's clinical and radiological scores.

Methods

Forty patients (80 knees) were included in this cross-sectional study. Medial as well as lateral tibiofemoral joint space widths (JSW) were measured using vernier callipers on printed, calibrated radiographic images. Knee Society Score (Function) (KSS-F) was used as the clinical outcome measure while Ahlbäck grade was used for determining radiological severity. JSW was correlated with KSS-F and the Ahlbäck grade using Spearman's rho correlation coefficient. Reproducibility of the method was assessed using the intra-class correlation coefficient (ICC).

Results

Average age of the participants was 60 ± 7.65 (range 50–78) years, with 18 males and 22 females. ICC for intraobserver reliability was 0.97 and for inter-observer reliability, was 0.91 (AP view) and 0.92 (LS view), respectively. Medial JSW measurements taken on the AP view were found to have a significantly higher degree of correlation with both KSS-F and Ahlbäck grade ( p  < 0.05) than those obtained from the LS view.

Conclusion

Although the LS view may be more sensitive for detecting early OA changes in knee, particularly in the lateral tibiofemoral compartment, the present study shows that AP view correlates better with the patient's overall clinical and radiological profile.

Comparison of Joint Space Width Determinations in Grade I and II Knee Osteoarthritis Patients Using Manual and Automatic Measurements

Background:

Examination of the knee to assess the narrowing of the joint gap or joint space width (JSW) is commonly done by manually checking radiographs and measuring the JSW using a ruler.

Objective:

This study aims to compare manual and automatic measurements with the diagnosis of grade I and grade II knee osteoarthritis.

Material and Methods:

In this cross-sectional study, 40 patients with the criteria for primary osteoarthritis (OA), aged 46 to 65 years old had knee OA grades of either I or II. The knee image was evaluated by a computer program and a radiologist manually viewing and measuring the JSW joint gap using a ruler.

Results:

The results showed there were no differences in the measurement of JSW medial and JSW lateral manually in grade I and grade II knee OA, at p=0.605 and p=0.344, respectively. Whereas in the automatic measurements, there was a difference between JSW medial and lateral JSW in grade I and grade II knee OA, each with p<0.001. The manual JSW measurement between medial JSW and lateral JSW in grade I and II showed that the medial and lateral knee joints have a similar distance. In the automatic, the average value of measurement lateral JSW in OA grades I and II was greater than the medial JSW.

Conclusion:

Automatic measurements showed that both of medial and lateral JSW at grade II OA knee were narrower than the results at grade I. Automatic measurement of JSW results was more consistent than the manual measurement method.

Validation of joint space narrowing on plain radiographs and its relevance to partial knee arthroplasty

AIMS

To explore the clinical relevance of joint space width (JSW) narrowing on standardized-flexion (SF) radiographs in the assessment of cartilage degeneration in specific subregions seen on MRI sequences in knee osteoarthritis (OA) with neutral, valgus, and varus alignments, and potential planning of partial knee arthroplasty.

METHODS

We retrospectively reviewed 639 subjects, aged 45 to 79 years, in the Osteoarthritis Initiative (OAI) study, who had symptomatic knees with Kellgren and Lawrence grade 2 to 4. Knees were categorized as neutral, valgus, and varus knees by measuring hip-knee-angles on hip-knee-ankle radiographs. Femorotibial JSW was measured on posteroanterior SF radiographs using a special software. The femorotibial compartment was divided into 16 subregions, and MR-tomographic measurements of cartilage volume, thickness, and subchondral bone area were documented. Linear regression with adjustment for age, sex, body mass index, and Kellgren and Lawrence grade was used.

RESULTS

We studied 345 neutral, 87 valgus, and 207 varus knees. Radiological JSW narrowing was significantly (p < 0.01) associated with cartilage volume and thickness in medial femorotibial compartment in neutral (r = 0.78, odds ratio (OR) 2.33) and varus knees (r = 0.86, OR 1.92), and in lateral tibial subregions in valgus knees (r = 0.87, OR 3.71). A significant negative correlation was found between JSW narrowing and area of subchondral bone in external lateral tibial subregion in valgus knees (r = -0.65, p < 0.01) and in external medial tibial subregion in varus knees (r = -0.77, p < 0.01). No statistically significant correlation was found in anterior and posterior subregions.

CONCLUSION

SF radiographs can be potentially used for initial detection of cartilage degeneration as assessed by MRI in medial and lateral but not in anterior or posterior subregions. Cite this article: Bone Joint Res 2021;10(3):173-187.

The posterior-anterior-flexed view is essential for the evaluation of valgus osteoarthritis. A prospective study on 134 valgus knees

Background

Radiographic imaging is an important tool to assess osteoarthritis (OA). Lateral compartment osteoarthritis (valgus OA) usually starts with cartilage degeneration along the posterior aspect of the lateral femoral condyle. There is evidence that the posterior-anterior (PA)-flexed view is more sensitive when diagnosing early stages of valgus OA compared to the anterior-posterior (AP) view. The current paper analyzes the value of the PA-flexed view for patients scheduled for total knee arthroplasty (TKA).

Methods

Radiographs of 134 valgus knees were assessed prior to TKA. The minimal joint space width (minJSW) was measured on AP and PA-flexed views. The extent of mechanical deformity was measured on hip to ankle standing films.

Results

49 (36.6%) AP views showed Kellgren and Lawrence (K/L)-grade 4 osteoarthritis in the lateral compartment, 82 (63.4%) showed grade 3 or less. The PA-flexed view resulted in an increased K/L-grading to grade 4 for 53 knees (62.4%) that were considered grade 3 or less on standard AP-radiographs. There was a significant differences between lateral minJSW on AP and PA-flexed view for patients with up to 10 degrees of mechanical valgus deformity (p < 0.001), as well as 11 to 15 degrees of mechanical deformity (p = 0.021). Only knees with severe deformity of more than 15 degrees did not show a difference in minJSW between PA-flexed view and AP view (p = 0.345).

Conclusions

The PA-flexed view is superior to the standard AP view in quantifying the extent of valgus OA in patients with zero to fifteen degrees of valgus deformity. It is recommended for the initial assessment of patients with valgus osteoarthritis and better documents the extent of osteoarthritis prior to TKA.

The posterior-anterior flexed view is better than the anterior-posterior view for assessing osteoarthritis of the knee

OBJECTIVE

The aim of this study is to determine whether the posterior-anterior (PA)-flexed view improves the radiographic assessment of patients with knee pain compared with the standard standing anterior-posterior radiograph.

MATERIALS AND METHODS

Three hundred and sixty-five patients with knee pain underwent anterior-posterior (AP), PA flexed, lateral, and Merchant radiographs of the knee. Knees were grouped as mild (Kellgren and Lawrence [K-L] 1-2) or severe (K-L 3-4) osteoarthritis (OA) and either varus (medial compartment), valgus (lateral compartment), or patellofemoral OA.

RESULTS

In knees with mild valgus OA on AP view (K-L 1-2), the PA flexed view was more sensitive than the AP view. The measured lateral minimal joint space width (minJSW) decreased more than 2 mm in 68% of the patients, resulting in an increase in K-L grade (3 or 4). In patients with severe valgus OA and in all patients with varus and patellofemoral OA, there was no difference between AP and PA flexed view with regard to radiographic measurements or KL grade. Based on the Medicare reimbursement rate using the PA flexed view alone instead of both views reduced imaging costs by 47%.

CONCLUSION

The PA flexed view better classifies the severity of lateral compartment disease in patients with mild valgus OA and provides comparable diagnostic sensitivity for joint space narrowing in varus- and patellofemoral OA. Using the PA flexed view alone was more cost effective than using the combination of AP and PA flexed imaging.

Fixed-flexion view X-ray of the knee superior in detection and follow-up of knee osteoarthritis

A fixed flexion view (FFV) is useful for evaluating joint space when assessing the severity of osteoarthritis (OA) of the knee. We analyzed changes in joint space revealed by standing extended view (SEV) and FFV over a mean 4 years, to compare both views on their capacity to measure joint space width accurately at particular time points during follow-up.SEV and FFV images were acquired in patients with knee OA. The 81 patients (157 knees) followed up for ≥24 months were selected as study subjects. Medial joint space widths (MJSW), Kellgren-Lawrence (KL) grades, and reductions in MJSW on SEV (ΔSEV) and FFV (ΔFFV) were compared in knees evaluated by SEV and FFV.At both time-points, mean MJSW was significantly lower by FFV than by SEV. Mean MJSW was significantly lower at follow-up than at first examination by both SEV and FFV. At both time-points, the KL grade was higher by FFV than by SEV group. The ΔFFV was significantly greater than the ΔSEV. ΔSEV did not differ significantly among KL grades, but ΔFFV was significantly greater in patients with KL grade II than in patients with other KL grades.FFV is not only useful for evaluating joint space in knees with OA, but also for accurately evaluating the progression of OA. The risk of rapid progression of knee OA may be higher in patients with KL grade II, as determined by FFV. FFV may be superior to SEV in determining appropriate treatment strategies for knee OA.

Flexion Posteroanterior Radiographs Affect Both Enrollment for and Outcomes After Injection Therapy for Knee Osteoarthritis

BACKGROUND

Knee injection therapy is less effective for severe osteoarthritis (OA), specifically Kellgren-Lawrence (KL) grade 4. Patient selection for knee injection trials has historically been based on extension anteroposterior (AP) radiographic evaluation; however, emerging evidence suggests that KL grading using a flexion posteroanterior (PA) radiograph more accurately and reproducibly predicts disease severity. The impact of radiographic view on patient selection and outcome after knee injection therapy remains unknown.

HYPOTHESIS

A 45° flexion PA radiograph will reveal more advanced knee OA in certain patients. These patients will report worse pre- and postinjection outcomes.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Four raters independently graded extension AP and flexion PA radiographs from 91 patients previously enrolled in a knee injection trial. Patients determined to have KL grade 4 OA by any rater on extension AP radiographs were excluded. Among included patients, those upgraded to KL grade 4 on flexion PA radiographs by at least 2 raters constituted group 2, while all remaining patients constituted group 1. Demographic data and patient-reported outcome scores before injection and at 6 weeks, 3 months, 6 months, and 12 months postinjection were compared between groups.

RESULTS

Overall, 64 patients met the inclusion criteria, of which 19 patients (30%) constituted group 2. Compared with group 1, patients in group 2 were older (58.7 vs 52.3 years, P = .02), had worse visual analog scale pain scores before (6.6 vs 5.3, P = .03) and 6 months after injection (5.3 vs 3.5, P = .01), had less improvement in both Lysholm (8.5 vs 20.5, P = .02) and Short Form-12 physical component (-2.2 vs 1.7, P = .03) scores from preinjection to 6 months postinjection, and had less improvement in both Lysholm (1.6 vs 13.1, P = .03) and Knee injury and Osteoarthritis Outcome Score sport subscale (-2.1 vs 16, P = .01) scores from preinjection to 12 months postinjection.

CONCLUSION

One in 3 patients considered to have mild to moderate knee OA on extension AP radiography is upgraded to severe knee OA (KL grade 4) on flexion PA radiography. These patients report worse preinjection outcomes, worse pain scores at short-term follow-up, and decreased improvement in knee function scores between 6 months and 1 year postinjection.

Radiographic Measurement of Joint Space Width Using the Fixed Flexion View in 1,102 Knees of Japanese Patients with Osteoarthritis in Comparison with the Standing Extended View

Purpose

The fixed flexion view (FFV) of the knee is considered useful for evaluating the joint space when assessing the severity of osteoarthritis (OA) of the knee. To clarify the usefulness of FFV for evaluation of the joint space and severity of knee OA, this study evaluated changes in the joint space on the FFV and standing extended view (SEV) in patients with knee OA.

Materials and Methods

The SEV and FFV images were acquired in 567 patients (1,102 knees) who visited the hospital with a chief complaint of knee joint pain. Medial joint space width (MJSW) and Kellgren-Lawrence (K-L) classification assessed using the SEV and FFV images were compared.

Results

Mean MJSW was significantly smaller when assessed on the FFV than on the SEV (3.02±1.55 mm vs. 4.31±1.30 mm; p<0.001). The K-L grade was the same or higher on the FFV than on the SEV.

Conclusions

The FFV is more useful than the SEV for evaluating the joint space in OA knees. Treatment strategies in patients with knee OA should be determined based on routinely acquired FFV images.

The one-leg standing radiograph: An improved technique to evaluate the severity of knee osteoarthritis

Objectives

The purpose of this study was to compare the joint space width between one-leg and both-legs standing radiographs in order to diagnose a primary osteoarthritis of the knee.

Methods

Digital radiographs of 100 medial osteoarthritic knees in 50 patients were performed. The patients had undergone one-leg standing anteroposterior (AP) views by standing on the affected leg while a both-legs standing AP view was undertaken while standing on both legs. The severity of the osteoarthritis was evaluated using the joint space width and Kellgren-Lawrence (KL) radiographic classification. The t-test was used for statistical analysis.

Results

The mean medial joint space width found in the one-leg and in the both-legs standing view were measured at 1.8 mm and 2.4 mm, respectively (p < 0.001, 95% CI 0.5 to 0.7). 33%, 47.4% and 23.1% of the knees diagnosed with a KL grade of I, II and III in the both-legs standing views were changed to KL grade II, III and IV in the one-leg standing views, respectively. No changes for KL IV osteoarthritis diagnoses have been found between both- and one-leg standing views.

Conclusions

One-leg standing radiographs better represent joint space width than both-legs standing radiographs. 32% of both-legs standing radiographs have changed the KL grading to a more severe grade than that in the one-leg standing radiographs.

Cite this article: P. Pinsornsak, K. Naratrikun, S. Kanitnate, T. Sangkomkamhang. The one-leg standing radiograph: An improved technique to evaluate the severity of knee osteoarthritis. Bone Joint Res 2016;5:436–441. DOI: 10.1302/2046-3758.59.BJR-2016-0049.R1.

Femoro-tibial knee osteoarthritis: One or two X-rays? Results from a population-based study

OBJECTIVE

Our objective was to compare the use of both anteroposterior (AP) extended-knee X-ray and semi-flexed X-ray (current gold standard) versus the use of semi-flexed X-ray alone to detect femoro-tibial osteoarthritis (OA).

METHODS

Individuals 40 to 75 years of age with symptomatic hip and/or knee OA (Kellgren/Lawrence [KL] score≥2) were recruited using a multiregional prevalence survey in France. Both AP and schuss X-rays were performed and read; two years later, the same examiner, blinded to the results of the first reading, performed a second reading of the schuss X-ray. We compared the KL stages of each knee and analyzed osteophyte detection and localization, joint space narrowing (JSN), and the relationship to obesity.

RESULTS

The analysis included 350 participants with OA of various stages. Comparing the two readings showed that a higher proportion of patients had KL≥2 when the two X-ray views were combined (right knee: P<0.0001; left knee: P<0.001). There were no differences when using the schuss X-ray alone versus in combination with an AP X-ray in terms of detecting JSN, osteophytes. A comparison of schuss X-ray alone versus AP X-ray alone demonstrated the superiority of the schuss view for evaluating JSN (P=0.0001 and P=0.0001) and no difference in osteophyte detection.

CONCLUSION

Our study shows that the schuss view alone was sufficient for detecting knee osteophytes and JSN. Using one X-ray rather than two will reduce medical costs and irradiation burden. Using two views seems preferable for epidemiological studies.

Sensitivity of standing radiographs to detect knee arthritis: a systematic review of Level I studies

PURPOSE

The purpose of this study was to perform a systematic review of the available literature to define the level of quality evidence for determining the sensitivity and specificity of different radiographic views in detecting knee osteoarthritis and to determine the impact of different grading systems on the ability to detect knee osteoarthritis.

METHODS

A systematic review of the literature was conducted to identify studies that evaluated the standing anteroposterior (AP) and 45° posteroanterior (PA) views for tibiofemoral and patellofemoral arthritis and those comparing the use of the Kellgren-Lawrence versus the joint space narrowing (JSN) radiographic grading systems using arthroscopy as the gold standard. A comprehensive search of PubMed, Scopus, CINAHL, the Cochrane Database, Clinicaltrial.gov, and EMBASE was performed using the keywords "osteoarthritis," "knee," "x-ray," "sensitivity," and "arthroscopy."

RESULTS

Six studies were included in the evaluation. The 45° flexion PA view showed a higher sensitivity than the standing AP view for detecting severe arthritis involving either the medial or lateral tibiofemoral compartment. There was no difference in the specificities for the 2 views. The direct comparison of the Kellgren-Lawrence and the JSN radiographic grading systems found no clinical difference between the 2 systems regarding the sensitivities, although the specificity was greater for the JSN system.

CONCLUSIONS

The ability to detect knee osteoarthritis continues to be difficult without using advanced imaging. However, as an inexpensive screening tool, the 45° flexion PA view is more sensitive than the standing AP view to detect severe tibiofemoral osteoarthritis. When evaluating the radiograph for severe osteoarthritis using either the Kellgren-Lawrence or JSN grading system, there is no clinical difference in the sensitivity between the 2 methods; however, the JSN may be more specific for ruling in severe osteoarthritis in the medial compartment.

LEVEL OF EVIDENCE

Level I, systematic review of Level I studies.

Imaging of cartilage and bone: promises and pitfalls in clinical trials of osteoarthritis

Imaging in clinical trials is used to evaluate subject eligibility, and/or efficacy of intervention, supporting decision making in drug development by ascertaining treatment effects on joint structure. This review focusses on imaging of bone and cartilage in clinical trials of (knee) osteoarthritis. We narratively review the full-text literature on imaging of bone and cartilage, adding primary experience in the implementation of imaging methods in clinical trials. Aims and constraints of applying imaging in clinical trials are outlined. The specific uses of semi-quantitative and quantitative imaging biomarkers of bone and cartilage in osteoarthritis trials are summarized, focusing on radiography and magnetic resonance imaging (MRI). Studies having compared both imaging methodologies directly and those having established a relationship between imaging biomarkers and clinical outcomes are highlighted. To make this review of practical use, recommendations are provided as to which imaging protocols are ideal for capturing specific aspects of bone and cartilage tissue, and pitfalls in their usage are highlighted. Further, the longitudinal sensitivity to change, of different imaging methods is reported for various patient strata. From these power calculations can be accomplished, provided the strength of the treatment effect is known. In conclusion, current imaging methodologies provide powerful tools for scoring and measuring morphological and compositional aspects of most articular tissues, capturing longitudinal change with reasonable to excellent sensitivity. When employed properly, imaging has tremendous potential for ascertaining treatment effects on various joint structures, potentially over shorter time scales than required for demonstrating effects on clinical outcomes.

Can standing knee radiographs predict chondral lesions in young- and middle-aged population?

PURPOSE

The aim of the study is to investigate the correlation between arthroscopic findings and joint space width on the standing knee radiographs at various flexion degrees in the young- and middle-aged patients with complaints of knee pain.

METHODS

Middle-aged patients with complaint of knee pain ongoing more than 6 months and failure in conservative treatment methods were included. Weight-bearing full extension, 30 and 45° of flexion radiographs were obtained. Joint space width was calculated on radiograms. Arthroscopy was performed to evaluate the chondral pathologies. Correlation analysis was performed.

RESULTS

Fourty-three patients (18 female, 25 male) with a mean age of 44.6 (20-63) were included. Mean joint space width was 4.87 mm ± 1.45 (2-10) mm in medial and 5.43 mm ± 1.47 (1-9) in lateral on standing extension radiographs. In 30° flexion radiographs, mean joint space width was 4.33 mm ± 1.25 (1.5-7.5) in medial and 5.36 mm ± 1.69 (1-9) in lateral. In 45° flexion radiographs, medial joint space was 4.28 mm ± 1.59 (2-9) in medial and 5.15 mm ± 1.59 (1.5-9) in lateral. In arthroscopic evaluation, one knee had grade 1 (2.3%), three knees had grade 2 (7%), nine knees had grade 3 (20.9%), and twelve knees had grade 4 (27.9%) lesions in the medial compartment. In the lateral compartment, two knees had grade 3 (4.7%) and one knee had grade 4 lesion (2.3%). Radiological data did not correlate with the arthroscopic findings.

CONCLUSION

Standing knee radiographs do not correlate with the arthroscopic findings in the middle-aged population with chondral lesions in knee joint.

LEVEL OF EVIDENCE

Case series with no comparison group, Level IV.

Relationship between knee alignment and radiographic markers of osteoarthritis: a cross-sectional study from a Korean population

AIM

The purpose of this paper was to investigate the relationship between static varus knee alignment and the radiographic markers of knee osteoarthritis (OA), including joint space narrowing (JSN) and Kellgren-Lawrence (K-L) grading scale.

METHOD

Knee alignment was measured by mechanical axis from weight-bearing anteroposterior (AP) radiographs of 251 symptomatic knees with radiological signs of OA (K-L grade ≥ 1). Linear correlation between knee varus alignment and variables, including joint space width (JSW) and K-L grades of tibiofemoral (TF) joint in extension or 45° flexion and patellofemoral (PF) joints were investigated. Multiple linear regression analyses were also performed to examine independent associations between varus knee alignment and JSW. Analysis of covariance (ancova) was performed to analyze the difference in knee alignment among K-L grade category groups adjusted for physical variables.

RESULTS

Varus knee alignment was negatively correlated with JSW of medial TF joint in extension AP (r = -0.460, P = 0.0001) and 45° flexion PA views (r = -0.476, P = 0.0001) and PF JSN (r = -0.168, P = 0.008). Multiple linear regression analysis adjusted for physical variables showed that the varus knee alignment was negatively associated with the JSW of medial TF joint in extension AP (P = 0.0001) and 45° flexion PA view (P = 0.0001). ancova adjusted for physical variables showed that knees in K-L grade 4 had significantly greater varus alignment than those in K-L grades 1-3 in AP (P = 0.0001), 45° flexion PA view (P = 0.0001), and PF joint (P = 0.0001~0.001).

CONCLUSION

Varus knee alignment is associated with the radiographic measures of knee OA severity.

Advances in imaging of osteoarthritis and cartilage

Osteoarthritis (OA) is the most frequent form of arthritis, with major implications for individual and public health care without effective treatment available. The field of joint imaging, and particularly magnetic resonance (MR) imaging, has evolved rapidly owing to technical advances and the application of these to the field of clinical research. Cartilage imaging certainly is at the forefront of these developments. In this review, the different aspects of OA imaging and cartilage assessment, with an emphasis on recent advances, will be presented. The current role of radiography, including advances in the technology for joint space width assessment, will be discussed. The development of various MR imaging techniques capable of facilitating assessment of cartilage morphology and the methods for evaluating the biochemical composition of cartilage will be presented. Advances in quantitative morphologic cartilage assessment and semiquantitative whole-organ assessment will be reviewed. Although MR imaging is the most important modality in imaging of OA and cartilage, others such as ultrasonography play a complementary role that will be discussed briefly.

Spatial patterns of cartilage loss in the medial femoral condyle in osteoarthritic knees: data from the Osteoarthritis Initiative

The objective of this study was to develop a technique for analyzing spatial patterns of cartilage loss in the medial femoral condyle (MF), and to study MF cartilage loss in participants of the Osteoarthritis Initiative. Using a 0.7 mm sagittal double echo at steady state (DESS) sequence, 160 osteoarthritic knees from 80 participants with varying degrees of medial joint space narrowing were imaged at baseline and 1-year follow-up. MF cartilage was segmented and cartilage loss determined. Rate of change varied significantly (P = 0.0067) along the anterior-posterior extension of the MF, with the greatest changes (-45 microm, -2.7%) observed 30-60 degrees posterior to the trochlear notch. The rate was greater in the central MF after excluding peripheral aspects of the MF from analysis. Sensitivity to change was greatest at 45-75 degrees (standardized response mean = -0.32) but was minimally affected by medial-lateral trimming. In conclusion, the greatest sensitivity to change was achieved when analyzing the posterior aspect of the central, weight-bearing MF.

Magnitude and regional distribution of cartilage loss associated with grades of joint space narrowing in radiographic osteoarthritis--data from the Osteoarthritis Initiative (OAI)

OBJECTIVE

Clinically, radiographic joint space narrowing (JSN) is regarded a surrogate of cartilage loss in osteoarthritis (OA). Using magnetic resonance imaging (MRI), we explored the magnitude and regional distribution of differences in cartilage thickness and subchondral bone area associated with specific Osteoarthritis Research Society International (OARSI) JSN grades.

METHOD

Seventy-three participants with unilateral medial JSN were selected from the first half (2678 cases) of the OA Initiative cohort (45, 21, and 7 with OARSI JSN grades 1, 2, and 3, respectively, no medial JSN in the contra-lateral knee). Bilateral sagittal baseline DESSwe MRIs were segmented by experienced operators. Intra-person between-knee differences in cartilage thickness and subchondral bone areas were determined in medial femorotibial subregions.

RESULTS

Knees with medial OARSI JSN grades 1, 2, and 3 displayed a 190 microm (5.2%), 630 microm (18%), and 1560 microm (44%) smaller cartilage thickness in weight-bearing medial femorotibial compartments compared to knees without JSN, respectively. The weight-bearing femoral condyle displayed relatively greater differences than the posterior femoral condyle or the medial tibia (MT). The central subregion within the weight-bearing medial femur (cMF) of the femoral condyle (30-75 degrees ), and the external and central subregions within the tibia displayed relatively greater JSN-associated differences compared to other medial femorotibial subregions. Knees with higher JSN grades also displayed larger than contra-lateral femorotibial subchondral bone areas.

CONCLUSIONS

This study provides quantitative estimates of JSN-related cartilage loss, with the central part of the weight-bearing femoral condyle being most strongly affected. Knees with higher JSN grades displayed larger subchondral bone areas, suggesting that an increase in subchondral bone area occurs in advanced OA.

Radiographic grading and measurement of joint space width in osteoarthritis

The progression of osteoarthritis is traditionally measured using radiographic joint space width (JSW). Numerous knee radiograph protocols have been developed with various levels of complexity and performance as it relates to detecting JSW loss (ie, joint space narrowing). Sensitivity to joint space narrowing is improved when radioanatomic alignment of the medial tibial plateau is achieved. Semiautomated software has been developed to improve the accuracy of JSW measurement over manual methods. JSW measurements include minimum JSW, mean JSW or joint space area, and JSW at fixed locations.

Risk stratification for knee osteoarthritis progression: a narrative review

OBJECTIVE

A narrative review describing the assessment of osteoarthritis (OA) progression, and more specifically the risk factors which assist in delineating strata of individuals at greatest risk for more rapid progression.

DESIGN

A narrative review based on selected recent medical literature.

RESULTS

With little currently available in the treatment of this disease, better understanding of responsive and valid endpoints is essential to identifying potential new interventions for treatment of OA. Efforts to stratify those at greatest risk for progression can use a number of systemic or local risk factors that may assist in delineating populations at greater risk for progression.

CONCLUSIONS

Current data suggests that stratification of risk is feasible to ascertain those at risk for rapid progression using a number of different metrics including knee alignment, meniscal damage, bone marrow lesions and late stage disease. Identifying persons at greatest risk for progression has important implications for clinical trial planning and can enhance study efficiency.

Radiologic markers of osteoarthritis progression

PURPOSE OF REVIEW

To review radiographic and MRI developments in measuring osteoarthritis progression in the tibiofemoral compartment of the knee.

RECENT FINDINGS

Standardized techniques for measuring joint space width in the medial tibiofemoral compartment, using standardized radiographic protocols, have become accepted for quantifying changes in tibiofemoral in knee osteoarthritis. In addition, there is a significant body of supporting data on the longitudinal change in MRI-derived cartilage morphology (thickness, volume) as an end point to reflect osteoarthritis progression/cartilage loss.

SUMMARY

This review appraises the current methods of measurement of osteoarthritis progression and limitations with regards their interpretation and further development.

Proximal gait adaptations in medial knee OA

The purpose of this study was to examine interlimb differences in gait kinematics and kinetics in patients with symptomatic medial knee OA. The main objective was to identify hip joint movement strategies that might lower the knee adduction moment and also compensate for decreased knee flexion during weight acceptance. Gait analysis was performed on 32 patients with moderate medial compartment knee OA. Kinetic and kinematic data were calculated and side-to-side comparisons made. Radiographs were used to identify frontal plane alignment. No interlimb difference in the peak knee adduction moment was found (p = 0.512), whereas a greatly reduced hip adduction moment was seen on the involved side (p < 0.001) during the early part of stance. The involved limb flexed significantly less and hip and knee flexion moments were smaller compared to the uninvolved side. Gait adaptations involving a lateral sway of the trunk may successfully lead to relatively lower ipsilateral knee adduction moments, and would further be reflected by a lower adduction moment at the hip. Subjects did not compensate for less knee flexion by any dynamic means, and likely experience a resulting higher joint impact. These gait adaptations may have implications with respect to development of weakness of the ipsilateral hip musculature and progression of multiarticular OA.

A mechanical theory for the effectiveness of bracing for medial compartment osteoarthritis of the knee

BACKGROUND

Evidence that knee braces used for the treatment of osteoarthritis mediate pain relief and improve function by unloading the joint (increasing the joint separation) remains inconclusive. Alternatively, valgus-producing braces may mediate pain relief by mechanically stabilizing the joint and reducing muscle cocontractions and joint compression. In this study, therefore, we sought to examine the degree to which so-called unloader braces control knee instability and influence muscle cocontractions during gait.

METHODS

Sixteen subjects with radiographic evidence of knee malalignment and medial compartment osteoarthritis were recruited and fitted with a custom Generation II Unloader brace. Gait analysis was performed without use of the brace and with the brace in neutral alignment and in 4 degrees of valgus alignment. A two-week washout period separated the brace conditions. Muscle cocontraction indices were derived for agonist and antagonist muscle pairings. Pain, instability, and functional status were obtained with use of self-reported questionnaires, and the results were compared.

RESULTS

The scores for pain, function, and stability were worst when the knee was unsupported (the baseline and washout conditions). At baseline, nine of the sixteen patients reported knee instability and five of the nine complained that it affected their activities of daily living. Poor knee stability was found to be correlated with low ratings for the activities of daily living, quality of life, and global knee function and with increased pain and symptoms. Knee function and stability scored best with the brace in the neutral setting compared with the brace in the valgus setting. The cocontraction of the vastus lateralis-lateral hamstrings was significantly reduced from baseline in both the neutral (p = 0.014) and valgus conditions (p = 0.023), and the cocontraction of the vastus medialis-medial hamstrings was significantly reduced with the valgus setting (p = 0.068), as a result of bracing. Patients with greater varus alignment had greater decreases in vastus lateralis-lateral hamstring muscle cocontraction.

CONCLUSIONS

When knees with medial compartment osteoarthritis are braced, neutral alignment performs as well as or better than valgus alignment in reducing pain, disability, muscle cocontraction, and knee adduction excursions. Pain relief may result from diminished muscle cocontractions rather than from so-called medial compartment unloading.

Longitudinal performance evaluation and validation of fixed-flexion radiography of the knee for detection of joint space loss

OBJECTIVE

The ability of nonfluoroscopically guided radiography of the knee to assess joint space loss is an important issue in studies of progression and treatment of knee osteoarthritis (OA), given the practical limitations of protocols involving fluoroscopically guided radiography of the knee. We evaluated the ability of the nonfluoroscopically guided fixed-flexion radiography protocol to detect knee joint space loss over 3 years.

METHODS

We assessed the same-day test-retest precision for measuring minimum joint space width (JSW), the sensitivity for detection of joint space loss using serial films obtained a median of 37 months (range 23-47 months) apart, and the relationship of joint space loss to radiographic and magnetic resonance imaging (MRI) measures of knee OA. Participants were men and women (ages 70-79 years) with knee pain who were participating in the Health, Aging, and Body Composition Study. We assessed baseline radiographic OA and measured JSW using a computerized algorithm. Serial knee MRIs obtained over the same interval were evaluated for cartilage lesions.

RESULTS

A total of 153 knees were studied, 35% of which had radiographic OA at baseline. The mean +/- SD joint space loss for all knees over 3 years was 0.24 +/- 0.59 mm (P < 0.001 for change). In knees with OA at baseline, the mean +/- SD joint space loss over 3 years was 0.43 +/- 0.66 mm (P < 0.001), and in knees with joint space narrowing at baseline, joint space loss was 0.50 +/- 0.67 mm (P < 0.001). Joint space loss and its standardized response mean increased with the severity of baseline joint space narrowing and with the presence of cartilage lesions at baseline and worsening during followup.

CONCLUSION

Radiography of the knee in the fixed-flexion view provides a sensitive and valid measure of joint space loss in multiyear longitudinal studies of knee OA, without the use of fluoroscopy to aid knee positioning.

Experience with a placebo-controlled randomized clinical trial of a disease-modifying drug for osteoarthritis: the doxycycline trial

Little effort has gone into the development of more effective analgesics for osteoarthritic pain. Efforts to improve symptomatic therapy for osteoarthritis have been deflected or diluted by a decision to pursue the development of disease-modifying OA drugs (DMOADs). These agents' main mechanism of action is directed not at the relief of joint pain but at slowing the progression of structural damage. This article describes the results of a recent randomized placebo-controlled designed to examine the DMOAD effect in humans of the tetracycline antibiotic doxycycline, and reviews the experience gained from other recent DMOAD trials in humans.

Radiographs are not useful in detecting arthroscopically confirmed mild chondral damage

Preoperatively predicting chondral damage is important. Weightbearing radiographs, including the standing anteroposterior and 45 degrees flexion posteroanterior views traditionally have been used for this purpose. We wanted to determine if one radiograph had superior sensitivity or specificity in detecting arthroscopically confirmed Grade II chondromalacia (mild arthritis). A standard prospective standing radiographic protocol was designed for all patients who presented to a sports medicine center with knee complaints. Patients who had subsequent arthroscopic surgery had their radiographs measured in a blinded manner for articular cartilage intervals in millimeters to detect joint-space narrowing. Intraarticular chondral damage was correlated with the radiographic findings. Three hundred forty-nine of a possible 411 (87%) patients during a 2-year period had both radiographs and subsequent arthroscopic grading of chondromalacia. This has been the largest study that correlated arthroscopic chondromalacia grades with two commonly preferred weightbearing radiograph projections. Despite specificities greater than 90%, the sensitivity was extremely low and neither standing radiograph was superior. Neither radiograph was useful in detecting Grade II chondral damage.

LEVEL OF EVIDENCE

Diagnostic study, Level I-1 (testing of previously developed diagnostic criteria in series of consecutive patients--with universally applied reference "gold" standard). See the Guidelines for Authors for a complete description of levels of evidence.

Review of the anatomical and radiological differences between fluoroscopic and non-fluoroscopic positioning of osteoarthritic knees

OBJECTIVE

To determine the differences in the radioanatomical appearance of the tibiofemoral compartment in knees radiographed in the fluoroscopic semiflexed, semiflexed MTP and fixed flexion methods compared to that obtained in the extended knee position. To assess the differences in the radiological procedures between the fluoroscopic and nonfluoroscopic semiflexed methods of radiography.

METHODS

Based on anatomical principals to describe the differences in (1) the content of the joint space in knees radiographed in the extended and semiflexed positions and (2) the sectional plane for joint space width (JSW) measurement in radiographs of knees positioned in the extended, fluoroscopic guided semiflexed, MTP and fixed flexion positions. From published procedures to determine the factors that affect study costs, X-ray technologists operating time and film processing in fluoroscopic and nonfluoroscopic methods of radiography.

RESULTS

Medial compartment JSW from semiflexed methods only accurately measures cartilage thickness. All semiflexed methods reproducibly reposition the joint within any one patient. The angle at the tibiofemoral joint varies little between patients in the fluoroscopic semiflexed, less in the MTP and more so in the fixed flexion positions; the latter is due to the effect weight-associated differences in thigh girth. The sectional plane of JSW measurement is generally similar within the three views. Compared to the fluoroscopic method the radiological procedures of the nonfluoroscopic techniques were less demanding.

CONCLUSION

The MTP and fixed flexion methods are much easier to use than the fluoroscopic method. They reproducibly reposition the knee within patient knees and between knees in the MTP but less so in the fixed flexion view.

A new plain radiography method using the optimal angle of knee flexion for assessing early degeneration of the knee joint

During total knee arthroplasty for primary osteoarthritis, we measured the area of worn cartilage on the medial femoral condyle in 44 knees. By reference to a lateral femoral radiograph of each knee, the optimal knee flexion angle-reflecting the worn area of the femoral condyle-was determined and found to be 19.8 degrees +/- 7.6 degrees. Using this result, a new method for posteroanterior radiography of the weight-bearing knee (20/10 radiography) was devised. We compared the use of our method with Rosenberg's method in 56 varus knees and found that the width of the cartilage space determined by our method was narrower than that determined by Rosenberg's method (t test, <0.001). These results confirmed that 20/10 radiography well reflects the region of worn cartilage in knees with early-stage primary osteoarthritis.

Ultrasonographic findings in knee osteoarthritis: a comparative study with clinical and radiographic assessment

OBJECTIVE

To compare ultrasonographic (US) findings with clinical and radiographic assessment in knee osteoarthritis (OA).

METHODS

Fifty patients with primary knee OA were studied. Clinical assessment of both knees was performed by the same rheumatologist who recorded a visual analogue scale (VAS) for pain (VASP). All patients underwent a US examination of their knees by a second blinded rheumatologist. Weight-bearing anteroposterior and lateral knee radiographs were read by a third blinded rheumatologist who assessed the Kellgren and Lawrence (K-L) grade, the femorotibial (FT) space width and the presence of patello-femoral degenerative signs.

RESULTS

Forty patients had bilateral symptomatic knee OA and 10 unilateral symptomatic OA. All knees showed radiographic FT degenerative signs. US findings in symptomatic knees were effusion (47%), protrusion of the medial meniscus (MMP) with displacement of the medial collateral ligament (MCLD) (61%) and Baker's cyst (22%). US effusion, MMP and MCLD were associated with a significantly higher VAS score for pain (P<0.05). MMP was associated with medial FT space width (P<0.05). Patients who had a difference between VAS score for pain in each knee greater than 30 (28 patients) showed significantly more unilateral effusion, MMP, MCLD and worse K-L grade in the more symptomatic knee than those with a difference lesser than 30 (22 patients).

CONCLUSION

Knee effusion and MMP with MCLD are associated with pain in knee OA. In addition, MMP may contribute to the radiographic medial FT space narrowing. We propose US for assessing periarticular and intraarticular abnormalities involved in the pathophysiology of knee OA.

Hauteur radiologique de l’interligne fémoro-tibial médial avant et immédiatement après méniscectomie

PURPOSE OF THE STUDY

The purpose of this prospective study was to develop and evaluate a method for measuring the femorotibial joint space and to assess the effect of meniscectomy.

MATERIAL AND METHODS

This study was conducted in a consecutive series of 36 patients undergoing arthroscopic meniscectomy for lesions of the medial meniscus on a stable knee. The height of the joint space was measured on x-rays taken in the morning before the operation then ten days later. X-rays were obtained for both knees in complete extension and in the 30 degrees flexion position. The height of the joint space was measured on the digital version of the x-rays midway between the vertical tangents of the posterior limits of the medial condyle.

RESULTS

Readings were not reader dependent and demonstrated no significant difference between the pre and postmeniscectomy height of the medial femorotibial space (30 degrees flexion view, 5.2 +/- 1 and 5.2 +/- 1 before meniscectomy for reader 1 and 5.2 +/- 1 and 5.2 +/- 1 for reader 2 (p=0.05 for Student-Fisher test for paired values). The heights measured by the two readers were correlated (correlation coefficient test).

DISCUSSION

The height of the medial femorotibial joint space can be measured reproductibly on plain x-rays of the knee in the standard flexion position. We were unable to demonstrate any significant difference in joint space between measures taken before and after meniscectomy.

A parallel approach: the impact of schuss radiography of the degenerate knee on clinical management

Schuss radiographs are PA weight bearing views of the knee taken in 30 degrees of flexion. Several studies have shown them to be more sensitive detectors of osteoarthritic changes in the knee than standard extension AP views. We compared the plans of management proposed by eight consultant orthopaedic surgeons to two case presentations of each of a series of 50 patients with tibiofemoral osteoarthritis. The clinical and radiological information provided on each patient was identical in the two presentations except that on one occasion the surgeons were shown the extension AP radiograph while on the other it was replaced by the schuss view. The panel altered their management plan in over 40% of cases. This represented a reduction of almost 50% in arthroscopies in the schuss group with a move towards definitive surgery. The total number of procedures proposed was also reduced. The radiograph was useful determining the management of patients with predominantly lateral, as well as medial or generalised symptoms. We conclude that the schuss radiograph is a valuable tool in the assessment of knee osteoarthritis the use of which can alter clinical management. By reducing non-therapeutic arthroscopies it may significantly reduce total number of operations to be performed in this patient group.

Standing radiographs underestimate joint width: comparison before and after resection of the joint in 34 total knee arthroplasties

BACKGROUND

Measurement or estimation of joint width is routinely used in the preoperative evaluation of gonarthrosis. To our knowledge, the validity and reproducibility of this procedure has not been adequately studied.

PATIENTS AND METHODS

We measured joint width in 34 knees (medial arthrosis: n = 22, lateral arthrosis: n = 12) on preoperative weight-bearing radiographs and on radiographs of the corresponding part of the joint after knee arthroplasty. The bone/cartilage pieces were placed in anatomical positions and loaded in a jig made of perspex. High-density film was used to obtain maximum resolution.

RESULTS

In medial and lateral arthrosis, the minimum joint widths were median 0.3 and 0.2 mm smaller on the radiographs of the specimens (p = 0.05, 0.04). In lateral arthrosis the differences were more scattered (95% CI: lateral: 0.1 to -1.2 mm; medial: 0 to -0.5 mm), suggesting less precise determination.

INTERPRETATION

In medial arthrosis, the degree of underestimation is usually small and acceptable. More pronounced discrepancies could be found in lateral arthrosis, calling for the use of further diagnostic measures.

Radiographic evaluation of osteoarthritis

Osteoarthritis is the most widespread form of arthritis in the United States. Classically, osteoarthritis has been grouped into primary and secondary types. Primary or idiopathic osteoarthritis is believed to be a sequela of altered biomechanical stresses across joints in susceptible individuals. Secondary osteoarthritis is a consequence of underlying cartilage damage, such as from preceding inflammatory arthritis, metabolic abnormality, or injury. The radiographic hallmark of osteoarthritis is asymmetric loss of cartilage space. Osteophytosis bony eburnation, subchondral cysts, and eventual subluxation follow. Osteoporosis and erosions are not usual features of this disease.

Is knee radiography useful for studying the efficacy of a disease-modifying osteoarthritis drug in humans?

Recent research on the radiographic imaging of knee OA has helped clarify the features of imaging protocols that contribute to accurate representation of disease severity--specifically, the thickness of articular cartilage--and to sensitive detection of disease progression. The absence of standards for reproducible positioning of the knee in the conventional standing AP view obscures the true rate and variability of JSN in knee OA. Moreover, the standing AP view is susceptible to systematic bias insofar as longitudinal changes in knee pain might lead to over- or underestimation of radiographic JSW depending on the direction of change in pain. More recent protocols for standardized knee radiography have been designed to achieve reproducible alignment of the medical tibial plateau and x-ray beam. As a group these protocols permit measurement of tibiofemoral JSW with remarkable precision--the sine qua non of sensitivity to change--however, only limited longitudinal data is available to permit a direct evaluation of the suitability of these protocols for use in clinical DMOAD trials. Longitudinal studies published to date suggest that fluoroscopic positioning methods are superior to nonfluoroscopic methods with respect to reproducing the position of the knee in serial examinations performed several years apart. Fluoroscopic methods also appear to be superior with respect to achieving parallel alignment of the medial tibial plateau and x-ray beam in serial radiographs, a positioning marker strongly associated with sensitive detection of JSN in knee OA. It is important to note that while the various standardization protocols described in this article perform with great success in short-term demonstrations of the reproducibility of positioning and radiographic JSW, differences clearly exist between protocols in the quality of performance over intervals relevant to clinical DMOAD trials. Over intervals of 2 to 3 years, changes in patient characteristics (e.g., severity of knee pain, body weight, load bearing, varus--valgus deformity) and uncontrollable events related to radiography (e.g., technologist turnover, equipment upgrades) have ample opportunity to affect the technical quality of a radiological knee examination. It is difficult, therefore, to conclude whether or not an apparent difference with respect to sensitivity to OA progression between specific radiographic protocols, implemented in separate locations with different cohorts, reflects a robust difference in technical quality or uncontrollable patient variables and events. The most informative recent studies have provided the results of head-to-head longitudinal comparisons of alternative standardization protocols or conventional examination methods performed concurrently in the same subjects [20,22]. Additional comparative studies of this nature are needed, however, to fully characterize the strengths and weaknesses of currently available alternatives in a way that will permit generalizable conclusions regarding the best radiographic methods for multicenter DMOAD trials.

Joint space width of the tibiofemoral and of the patellofemoral joint in chronic knee pain with or without radiographic osteoarthritis: a 2-year follow-up

OBJECTIVES

To assess the interval change of the minimal joint space width (MJS) in radiographs of the tibiofemoral (TF) joint and of the patellofemoral (PF) joint with a 2-year follow-up in middle-aged people with longstanding knee pain with or without radiographic osteoarthritis (OA) and to study the precision of the MJS measurements.

DESIGN

In the format of a prospective study of early OA the signal knee in 55 people, 28 men and 27 women (aged 41-57 years, median 50), with chronic knee pain at inclusion was examined with a 2-year interval (median 25 months, range 21-30). The MJS of the TF joint was measured using a flexed PA view in weightbearing and the MJS of the PF joint using an axial view in standing.

RESULTS

The MJS of the TF joint decreased medially by 0.056+/-0.44mm (n.s.) and increased laterally by 0.080+/-0.51mm (n.s.) during the time of observation. In knees with an MJS medially that was less or the same as compared with the lateral compartment, the MJS decreased by 0.14+/-0.38mm (p=0.038) and in a subgroup of these knees, without osteophytes, the MJS decreased by 0.14+/-0.27mm (p=0.018). The MJS of the PF joint decreased by 0.019mm (n.s.) during the time of observation. The coefficient of variation for intra- and interobserver MJS measurements of the TF joint was 1.0 and 1.1% medially and 2.3 and 2.7% laterally, and for measurement error 6.9% medially and 4.8% laterally, respectively. The coefficient of variation for intra- and interobserver MJS measurements of the PF joint was 8.1 and 5.8% medially and 7.5 and 10.1% laterally and for the measurement error it was 8.1% medially and 8.5% laterally, respectively.

CONCLUSIONS

A statistically significant reduction of the MJS was only demonstrated in the medial compartment of the TF joint in those individuals who had an MJS in this compartment which was less or the same as compared with the lateral compartment as well as in a subgroup of these knees without osteophytes. The radiographic examinations and the MJS measurements were reproducible.

Imaging and osteoarthritis: what is the predictive value?

Recent protocols for standardized knee radiography, which attempts to image the knee with reproducible, parallel alignment of the medial tibial plateau and radiograph beam, possess many theoretic advantages. As a group, they permit measurement of tibiofemoral joint space width with remarkable precision--the sine qua non of sensitive detection of change. However, only limited longitudinal data are available in peer-reviewed publications to permit a direct evaluation of the suitability of these protocols for use in multicenter clinical trials and studies of biomarkers of osteoarthritis (OA) progression. Longitudinal data from several National Institutes of Health-supported studies of OA progression, as reflected in radiographs acquired with high levels of standardization for radioanatomic positioning of the knee, should be available in the next several years. Alternatively, data from the placebo groups of several industry-supported phase III trials of purported disease-modifying OA drugs, which were terminated prematurely because of adverse events or lack of efficacy, may be made available for rapid analysis regarding the performance of current standardization protocols with respect to their sensitivity to disease progression.

Detection of radiographic joint space narrowing in subjects with knee osteoarthritis: longitudinal comparison of the metatarsophalangeal and semiflexed anteroposterior views

OBJECTIVE

Although recent protocols for standardized knee radiography afford highly reproducible radioanatomic alignment of the joint and measurement of joint space width (JSW) in repeat radiographs acquired on the same day, the sensitivity of these techniques to joint space narrowing (JSN) over time in subjects with knee osteoarthritis (OA) is unknown. The present study was undertaken to compare the metatarsophalangeal (MTP) view and the semiflexed anteroposterior (AP) view with respect to sensitivity to JSN in knee OA.

METHODS

In 49 subjects with definite knee OA, 2 MTP radiographs and 1 semiflexed AP radiograph were obtained at baseline. Each examination was repeated 14 months later. In MTP views, minimum JSW and the distance between the anterior and posterior margins of the medial tibial plateau (intermargin distance [IMD], an indicator of parallel alignment of the tibial plateau and the x-ray beam) were measured with a pair of calipers and a magnifying lens fitted with a graticule. JSW in semiflexed AP views was measured by digital image analysis.

RESULTS

The mean of within-knee standard deviations of JSW in the baseline MTP examinations (n = 52 OA knees) was 0.24 mm (coefficient of variation 5.8%). Although IMDs in the 2 baseline MTP views were very highly correlated (+0.88), IMDs in the serial examinations were only moderately correlated (+0.45). Serial MTP views showed a small increase in mean JSW over 14 months that was not significantly greater than zero (mean +/- SD +0.09 +/- 0.66 mm; P not significant). In contrast, concurrent semiflexed AP examinations showed a marginally significant decrease in mean JSW (-0.09 +/- 0.31 mm; P = 0.10).

CONCLUSION

These results demonstrate that evidence of the short-term reproducibility of a radiographic protocol is an insufficient basis on which to predict the quality of its longitudinal performance.

Dynamic load at baseline can predict radiographic disease progression in medial compartment knee osteoarthritis

OBJECTIVE

To test the hypothesis that dynamic load at baseline can predict radiographic disease progression in patients with medial compartment knee osteoarthritis (OA).

METHODS

During 1991-93 baseline data were collected by assessment of pain, radiography, and gait analysis in 106 patients referred to hospital with medial compartment knee OA. At the six year follow up, 74 patients were again examined to assess radiographic changes. Radiographic disease progression was defined as more than one grade narrowing of minimum joint space of the medial compartment.

RESULTS

In the 32 patients showing disease progression, pain was more severe and adduction moment was higher at baseline than in those without disease progression (n=42). Joint space narrowing of the medial compartment during the six year period correlated significantly with the adduction moment at entry. Adduction moment correlated significantly with mechanical axis (varus alignment) and negatively with joint space width and pain score. Logistic regression analysis showed that the risk of progression of knee OA increased 6.46 times with a 1% increase in adduction moment.

CONCLUSIONS

The results suggest that the baseline adduction moment of the knee, which reflects the dynamic load on the medial compartment, can predict radiographic OA progression at the six year follow up in patients with medial compartment knee OA.

Anteroposterior weight-bearing radiography of the knee with both knees in semiflexion, using new equipment

In order to obtain high reproducibility and sensitivity in the evaluation of joint space in osteoarthritic knees, we used new equipment, and established an anteroposterior weight-bearing radiograph with both knees in semiflexion taking into account our investigation of the posterior slope angle. We compared our method with the Rosenberg method, and the coefficient of variation of our method showed higher reproducibility than that of the Rosenberg method. The most essential issue is whether the bilateral leg loading radiograph can show the same sensitivity as the homolateral leg loading radiograph. We compared standing radiographs of the knee in 26 degrees flexion with those of 26 degrees flexion in both knees. We assessed the widths of the narrowest points of the joint spaces in the medial and lateral compartments, the condylar plateau angle, and the femorotibial angle, in 47 knees in 24 patients. The data were analyzed statistically by single regression and each correlation was of statistical significance. Our method has better reproducibility and is more comfortable for the subject than conventional methods.