Assessment of the radioanatomic positioning of the osteoarthritic knee in serial radiographs: comparison of three acquisition techniques

Exploring relationships among multi-disciplinary assessments for knee joint health in service members with traumatic unilateral lower limb loss: a two-year longitudinal investigation

Motivated by the complex and multifactorial etiologies of osteoarthritis, here we use a comprehensive approach evaluating knee joint health after unilateral lower limb loss. Thirty-eight male Service members with traumatic, unilateral lower limb loss (mean age = 38 yr) participated in a prospective, two-year longitudinal study comprehensively evaluating contralateral knee joint health (i.e., clinical imaging, gait biomechanics, physiological biomarkers, and patient-reported outcomes); seventeen subsequently returned for a two-year follow-up visit. For this subset with baseline and follow-up data, outcomes were compared between timepoints, and associations evaluated between values at baseline with two-year changes in tri-compartmental joint space. Upon follow-up, knee joint health worsened, particularly among seven Service members who presented at baseline with no joint degeneration (KL = 0) but returned with evidence of degeneration (KL ≥ 1). Joint space narrowing was associated with greater patellar tilt (r[12] = 0.71, p = 0.01), external knee adduction moment (r[13] = 0.64, p = 0.02), knee adduction moment impulse (r[13] = 0.61, p = 0.03), and CTX-1 concentration (r[11] = 0.83, p = 0.001), as well as lesser KOOSSport and VR-36General Health (r[16] = - 0.69, p = 0.01 and r[16] = - 0.69, p = 0.01, respectively). This longitudinal, multi-disciplinary investigation highlights the importance of a comprehensive approach to evaluate the fast-progressing onset of knee osteoarthritis, particularly among relatively young Service members with lower limb loss.

Kellgren & Lawrence grading in cohort studies: methodological update and implications illustrated using data from the CHECK cohort

Objective

The Cohort Hip and Cohort Knee (CHECK) is a cohort of middle‐aged individuals with hip or knee pain. Radiographs were assigned Kellgren/Lawrence (K/L) scores under different conditions at each follow‐up visit for 10 years. We aimed to describe and consolidate each scoring approach, then illustrate implications of their use by comparing baseline K/L scores assigned using 2 of these approaches, and evaluating their respective associations with joint replacement and incident radiographic osteoarthritis (ROA).

Methods

We compared baseline K/L scores assigned to hips and knees using 2 scoring approaches: 1) assigned by senior researchers to baseline images alone and 2) assigned by trained readers, with images read paired and in known sequence with up to 10 years of follow‐up radiographs (Poisson regression). We evaluated the associations of baseline ROA (any: K/L grade ≥1; established: K/L ≥2) with joint replacement, and of K/L 1 joints with incident established ROA (survival analysis).

Results

Of 1,002 participants (79% women, mean ± SD age 55.9 ± 5.2 years, body mass index 26.2 ± 4.0 kg/m²), the second scoring approach had 2.4 times (95% confidence interval [95% CI] 1.8–3.1 for knees) and 2.9 times (95% CI 2.3–3.7 for hips) higher prevalence of established ROA than the first approach. Established hip ROA had a higher risk of joint replacement using the first approach (hazard ratio [HR] 24.2 [95% CI 15.0–39.8] versus second approach HR 7.7 [95% CI 4.9–12.1]), as did knees (HR 19.3 [95% CI 10.3–36.1] versus second approach HR 4.8 [95% CI 2.4–9.6]). The risk of incident ROA did not differ by approach.

Conclusion

This study demonstrates that evaluating ROA prevalence and predicting outcomes depends on the scoring approach.

Incidence and Prognostic Significance of the Segond Fracture in Patients Undergoing Anterior Cruciate Ligament Reconstruction

BACKGROUND

The Segond fracture is an avulsion of the anterolateral tibia that can be found in patients with an anterior cruciate ligament (ACL) tear. It is currently unclear if the Segond fracture needs treatment or if it heals spontaneously and if it is associated with an increased risk of failure after ACL reconstruction.

PURPOSE

To identify the incidence and spontaneous healing rate of Segond fractures in a consecutive cohort of patients undergoing ACL reconstruction and to examine the predictive value of the Segond fracture on the risk of undergoing revision surgery.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective review of a cohort undergoing isolated ACL reconstruction between 2002 and 2016 was performed. Radiographs from the time of injury and preoperative radiographs were evaluated for Segond fractures and healed Segond fractures. Descriptive data were extracted from an internal quality database. Statistical analyses were performed to investigate risk of revision surgery and to compare across subgroups of patients.

RESULTS

A total of 1364 patients were included in the study. The incidence of Segond fractures was 7.4%. In addition, 10.4% of patients displayed signs of healed Segond fractures. In total, 15.2% of patients had either 1 or both findings. The overall healing response of the fracture was 35.6%. Those with Segond fractures were older (P = .014) and had a shorter interval from injury to surgery (P = .003) as compared with the rest of the cohort. The incidence of Segond fractures was significantly higher in those injured during downhill skiing as compared with other injury mechanisms (P = .04). The Segond fracture did not represent an increased risk of undergoing revision when compared with the control group (not significant).

CONCLUSION

The incidence of conventional Segond fractures in patients with ACL injury was found to be in accordance with former studies. Accounting for the high incidence of healed Segond fractures, a much higher incidence (15%) was seen. Although the spontaneous healing rate from initial radiographs to preoperative imaging was only 36%, the presence of Segond fractures did not represent a higher risk of undergoing revision surgery.

The Relationship of Three-Dimensional Joint Space Width on Weight Bearing CT With Pain and Physical Function

Limitations of plain radiographs may contribute to poor sensitivity in the detection of knee osteoarthritis and poor correlation with pain and physical function. 3D joint space width, measured from weight bearing CT images, may yield a more accurate correlation with patients' symptoms. We assessed the cross-sectional association between 3D joint space width and self-reported pain and physical function. 528 knees (57% women) were analyzed from Multicenter Osteoarthritis Study participants. An upright weight bearing CT scanner was used to acquire bilateral, weight-bearing fixed-flexion images of the knees. A 3D dataset was reconstructed from cone beam projections and joint space width was calculated across the joint surface. The percentages of the apposed medial tibiofemoral joint surface with joint space width <2.0mm and <2.5mm respectively were calculated. Pain and physical function were measured using Western Ontario and McMaster Universities Osteoarthritis Index. Participants who reported greater pain severity tended to have a greater joint area with joint space width <2.0mm (p=.07 for the highest vs. the lowest tertile). Participants who reported greater functional limitations had a greater joint area with joint space width <2.0mm (p=.02 for the highest vs. the lowest tertile). There appears to be an association between the medial tibiofemoral area with joint space width <2.0mm and pain and physical function. This article is protected by copyright. All rights reserved.

EULAR recommendations for the use of imaging in the clinical management of peripheral joint osteoarthritis

The increased information provided by modern imaging has led to its more extensive use. Our aim was to develop evidence-based recommendations for the use of imaging in the clinical management of the most common arthropathy, osteoarthritis (OA). A task force (including rheumatologists, radiologists, methodologists, primary care doctors and patients) from nine countries defined 10 questions on the role of imaging in OA to support a systematic literature review (SLR). Joints of interest were the knee, hip, hand and foot; imaging modalities included conventional radiography (CR), MRI, ultrasonography, CT and nuclear medicine. PubMed and EMBASE were searched. The evidence was presented to the task force who subsequently developed the recommendations. The strength of agreement for each recommendation was assessed. 17 011 references were identified from which 390 studies were included in the SLR. Seven recommendations were produced, covering the lack of need for diagnostic imaging in patients with typical symptoms; the role of imaging in differential diagnosis; the lack of benefit in monitoring when no therapeutic modification is related, though consideration is required when unexpected clinical deterioration occurs; CR as the first-choice imaging modality; consideration of how to correctly acquire images and the role of imaging in guiding local injections. Recommendations for future research were also developed based on gaps in evidence, such as the use of imaging in identifying therapeutic targets, and demonstrating the added value of imaging. These evidence-based recommendations and related research agenda provide the basis for sensible use of imaging in routine clinical assessment of people with OA.

A new quantitative measure for radiologic osteoarthritis of the lateral knee compartment distinguishes patients with longstanding lateral meniscectomy from non-pathological knees

PURPOSE

Common radiologic scores to evaluate knee osteoarthritis (OA) have been widely used but are descriptive and may lack objectivity. The aim of this study was to develop a quantitative and objective radiologic measure for the evaluation of lateral knee compartment OA. Furthermore, we tested the reliability of this new measure and its correlation to well-accepted radiologic scores.

METHODS

This retrospective study was performed within the context of a multi-centre long-term follow-up (15-25 years) of a patient cohort after partial or total lateral meniscectomy (n = 36 knees). In addition, 99 radiographs of clinically and radiologically normal knees were obtained from a control group. Anteroposterior weight-bearing views (0°) and Schuss (45°) views were analysed. The joint height of the lateral knee compartment was measured on the lateral border (lateral joint space height) and in the centre (central joint space height, CJSH) and normalized with respect to the width of the lateral compartment (X). All measurements were taken independently by two observers, allowing for inter- and intra-observer reliability assessments. The results of the two groups were compared using an analysis of covariance. Finally, the correlations between the results and the Fairbank and Kellgren & Lawrence scores were determined using a Spearman ρ rank order correlation.

RESULTS

The normalized joint space height in the centre of the compartment on the Schuss view (CJSH/X) showed the highest intra- (ICC = 0.980) and inter-observer reliability (ICC = 0.982). There was a significant difference in CJSH/X between the control (0.19 ± 0.05) and the meniscectomized knees (0.08 ± 0.07) (p < 0.001). CJSH/X showed a significant decline of 11 % per 10 years in the meniscectomy group. A negative correlation could be found between CJSH/X and the Fairbank (ρ = -0.751; p < 0.001) and Kellgren & Lawrence scores (ρ = -0.712; p < 0.001). A cut-off value of 0.14 of CJSH/X was defined-representing one standard deviation below the mean of the control group-from which measurements were considered as pathologic.

CONCLUSION

The normalized joint space height measured in the centre of the lateral knee compartment from a Schuss view, CJSH/X, was highly reproducible and showed a significant correlation to established radiologic scores. This new measure has the advantage of being objective and dimensionless and thus independent of the size of the radiograph. The normative values provided by our healthy control knees are useful to help establish an early diagnosis of radiologic lateral knee compartment OA.

LEVEL OF EVIDENCE

Retrospective diagnostic study, Level III.

Change in knee structure and change in tibiofemoral joint space width: a five year longitudinal population-based study

Background

Change in knee cartilage volume is frequently used as a proxy for change in knee joint space width over time, but longitudinal data on these associations is limited. We aimed to determine whether change in knee cartilage volume, new or worsening meniscal extrusion (ME), meniscal tears and cartilage defects over 2.4 years correlated with change in joint space width (JSW) over 5 years in older community dwelling adults.

Methods

Participants (n = 153) had their right knee imaged using MR imaging and x-ray at baseline, and after 2.4 years (MRI) and 5 years (x-ray). Cartilage volume, cartilage defects, meniscal extrusions and meniscal tears were assessed on sagittal T1-weighted fat-suppressed MRI. JSW was assessed using standard fixed semi-flexed view radiographs, and scored on those with adequate alignment.

Results

Participants were 51–79 (mean 62) years old; 48 % were female. Cartilage volume reduced over time (medial −134 ± 202 μL/year, lateral −106 ± 165 μL/year, p < 0.001), as did JSW (medial −0.05 ± 0.16 mm/year, lateral −0.12 ± 0.24 mm/year, p < 0.001). In multivariable analysis, the only consistent predictor of change in JSW was new or worsening ME (medial tibia R² 3.1 %, p = 0.031; medial femur R² 3.2 %, p = 0.024); change in cartilage volume correlated with change in JSW laterally (R² 4.8 %, p = 0.007) and was borderline medially (R² 2.2 %, p = 0.064); there was no association for meniscal tears or cartilage defects. The magnitude of these associations were similar albeit somewhat greater for ME in participants with radiographic OA (R² 6.2 %, p = 0.017).

Conclusion

Change in ME and cartilage volume weakly predict change in JSW, but the vast majority of the variation remains unexplained. Since MRI examines cartilage directly while radiographs examine it indirectly, these results cast doubt on the validity of using JSW as a proxy measure of cartilage loss.

In vivo articular cartilage deformation: noninvasive quantification of intratissue strain during joint contact in the human knee

The in vivo measurement of articular cartilage deformation is essential to understand how mechanical forces distribute throughout the healthy tissue and change over time in the pathologic joint. Displacements or strain may serve as a functional imaging biomarker for healthy, diseased, and repaired tissues, but unfortunately intratissue cartilage deformation in vivo is largely unknown. Here, we directly quantified for the first time deformation patterns through the thickness of tibiofemoral articular cartilage in healthy human volunteers. Magnetic resonance imaging acquisitions were synchronized with physiologically relevant compressive loading and used to visualize and measure regional displacement and strain of tibiofemoral articular cartilage in a sagittal plane. We found that compression (of 1/2 body weight) applied at the foot produced a sliding, rigid-body displacement at the tibiofemoral cartilage interface, that loading generated subject- and gender-specific and regionally complex patterns of intratissue strains, and that dominant cartilage strains (approaching 12%) were in shear. Maximum principle and shear strain measures in the tibia were correlated with body mass index. Our MRI-based approach may accelerate the development of regenerative therapies for diseased or damaged cartilage, which is currently limited by the lack of reliable in vivo methods for noninvasive assessment of functional changes following treatment.

Diagnostic performance of 3D standing CT imaging for detection of knee osteoarthritis features

OBJECTIVE

To determine the diagnostic performance of standing computerized tomography (SCT) of the knee for osteophytes and subchondral cysts compared with fixed-flexion radiography, using MRI as the reference standard.

METHODS

Twenty participants were recruited from the Multicenter Osteoarthritis Study. Participants' knees were imaged with SCT while standing in a knee-positioning frame, and with postero-anterior fixed-flexion radiography and 1T MRI. Medial and lateral marginal osteophytes and subchondral cysts were scored on bilateral radiographs and coronal SCT images using the OARSI grading system and on coronal MRI using Whole Organ MRI Scoring. Imaging modalities were read separately with images in random order. Sensitivity, specificity and accuracy for the detection of lesions were calculated and differences between modalities were tested using McNemar's test.

RESULTS

Participants' mean age was 66.8 years, body mass index was 29.6 kg/m(2) and 50% were women. Of the 160 surfaces (medial and lateral femur and tibia for 40 knees), MRI revealed 84 osteophytes and 10 subchondral cysts. In comparison with osteophytes and subchondral cysts detected by MRI, SCT was significantly more sensitive (93 and 100%; p < 0.004) and accurate (95 and 99%; p < 0.001 for osteophytes) than plain radiographs (sensitivity 60 and 10% and accuracy 79 and 94%, respectively). For osteophytes, differences in sensitivity and accuracy were greatest at the medial femur (p = 0.002).

CONCLUSIONS

In comparison with MRI, SCT imaging was more sensitive and accurate for detection of osteophytes and subchondral cysts than conventional fixed-flexion radiography. Additional study is warranted to assess diagnostic performance of SCT measures of joint space width, progression of OA features and the patellofemoral joint.

Simulation on the internal structure of three-dimensional proximal tibia under different mechanical environments

Background

Bone can adjust its morphological structure to adapt to the changes of mechanical environment, i.e. the bone structure change is related to mechanical loading. This implies that osteoarthritis may be closely associated with knee joint deformity. The purposes of this paper were to simulate the internal bone mineral density (BMD) change in three-dimensional (3D) proximal tibia under different mechanical environments, as well as to explore the relationship between mechanical environment and bone morphological abnormity.

Methods

The right proximal tibia was scanned with CT to reconstruct a 3D proximal tibia model in MIMICS, then it was imported to finite element software ANSYS to establish 3D finite element model. The internal structure of 3D proximal tibia of young normal people was simulated using quantitative bone remodeling theory in combination with finite element method, then based on the changing pattern of joint contact force on the tibial plateau in valgus knees, the mechanical loading was changed, and the simulated normal tibia structure was used as initial structure to simulate the internal structure of 3D proximal tibia for old people with 6° valgus deformity. Four regions of interest (ROIs) were selected in the proximal tibia to quantitatively analyze BMD and compare with the clinical measurements.

Results

The simulation results showed that the BMD distribution in 3D proximal tibia was consistent with clinical measurements in normal knees and that in valgus knees was consistent with the measurement of patients with osteoarthritis in clinics.

Conclusions

It is shown that the change of mechanical environment is the main cause for the change of subchondral bone structure, and being under abnormal mechanical environment for a long time may lead to osteoarthritis. Besides, the simulation method adopted in this paper can more accurately simulate the internal structure of 3D proximal tibia under different mechanical environments. It helps to better understand the mechanism of osteoarthritis and provides theoretical basis and computational method for the prevention and treatment of osteoarthritis. It can also serve as basis for further study on periprosthetic BMD changes after total knee arthroplasty, and provide a theoretical basis for optimization design of prosthesis.

Contribution of regional 3D meniscus and cartilage morphometry by MRI to joint space width in fixed flexion knee radiography--a between-knee comparison in subjects with unilateral joint space narrowing

BACKGROUND

Radiographic joint space width (JSW) is considered the reference standard for demonstrating structural therapeutic benefits in knee osteoarthritis. Our objective was to determine the proportion by which 3D (regional) meniscus and cartilage measures explain between-knee differences of JSW in the fixed flexion radiographs.

METHODS

Segmentation of the medial meniscus and tibial and femoral cartilage was performed in double echo steady state (DESS) images. Quantitative measures of meniscus size and position, femorotibial cartilage thickness, and radiographic JSW (minimum, and fixed locations) were compared between both knees of 60 participants of the Osteoarthritis Initiative, with strictly unilateral medial joint space narrowing (JSN). Statistical analyses (between-knee, within-person comparison) were performed using regression analysis.

RESULTS

A strong relationship with side-differences in minimum and a central fixed location JSW was observed for percent tibial plateau coverage by the meniscus (r = .59 and .47; p<.01) and central femoral cartilage thickness (r = .69 and .75; p<.01); other meniscus and cartilage measures displayed lower coefficients. The correlation of central femoral cartilage thickness with JSW (but not that of meniscus measures) was greater (r = .78 and .85; p<.01) when excluding knees with non-optimal alignment between the tibia and X-ray beam.

CONCLUSION

3D measures of meniscus and cartilage provide significant, independent information in explaining side-differences in radiographic JSW in fixed flexion radiographs. Tibial coverage by the meniscus and central femoral cartilage explained two thirds of the variability in minimum and fixed location JSW. JSW provides a better representation of (central) femorotibial cartilage thickness, when optimal positioning of the fixed flexion radiographs is achieved.

Percutaneous injection of autologous, culture-expanded mesenchymal stem cells into carpometacarpal hand joints: a case series with an untreated comparison group

In the present study, we describe six patients who received autologous mesenchymal stem cell (MSC) therapy for symptomatic carpometacarpal (CMC) joint and hand osteoarthritis (OA). Six patients who received injections of adult autologous culture expanded MSCs in their thumb CMC joints were followed for 1 year posttreatment, and matched with four procedure candidates who remained untreated. We observed positive outcomes in the treatment group for both symptoms and function related to the OA, compared with a reported worsening among the untreated controls. While these results should be interpreted with caution because of the small number of treated subjects and lack of placebo control and randomization, we find sufficient evidence for further investigation of MSC therapy as an alternative to more invasive surgery in patients with OA of the hand.

Assessment of early tibiofemoral joint space width changes after anterior cruciate ligament injury and reconstruction: a matched case-control study

BACKGROUND

Progression of primary knee osteoarthritis (OA) is often quantified by measuring structural alterations of the joint such as those in tibiofemoral joint space width (JSW) over time. Limited information is available regarding changes that occur during the onset and progression of posttraumatic OA (PTOA) that are often associated with anterior cruciate ligament (ACL) injury. Furthermore, there is a paucity of information regarding JSW changes in healthy patients, making JSW interpretation challenging during early PTOA progression.

PURPOSE

To evaluate tibiofemoral JSW after ACL injury, ACL reconstruction, and rehabilitation compared with healthy, matched controls.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 39 ACL-injured patients and 32 matched controls were evaluated. Injured patients were assessed at presurgical baseline and after ACL reconstruction (mean follow-up, 46 months), as were controls. Bilateral, standing, fluoroscopy-assisted, and posterior-anterior metatarsal-phalangeal view knee radiographs were obtained at each visit and JSW was measured.

RESULTS

The JSW differences between knees in control patients were not significantly different and did not change over time. Baseline JSW differences in the ACL group were significantly different than in controls. Three patients (7.9% of total) had an increased JSW difference, and 1 patient (2.6%) had a decreased medial JSW difference. In the lateral compartment, 6 patients (15.8%) had a decreased JSW difference. At follow-up, 2 patients in the ACL group (5%) had a decreased medial JSW difference, and 3 (7.9%) had a significantly increased difference in relation to controls. Lateral compartment analyses revealed 7 (18.4%) patients with a significantly decreased JSW difference and no patients with an increased difference compared with controls.

CONCLUSION

One third of ACL-injured knees underwent significant JSW change soon after injury; consequently, evaluation of within-knee JSW changes over time in ACL-injured patients may not be appropriate with a study based on case-control analysis. The JSWs in the healthy knee of ACL-injured patients do not change over time, allowing this knee to be used as a control for the injured knee. This is important when evaluating the earliest stages of PTOA after ACL injury, when patients are asymptomatic and intervention may be most beneficial.

Individual magnetic resonance imaging and radiographic features of knee osteoarthritis in subjects with unilateral knee pain: the health, aging, and body composition study

OBJECTIVE

Strong associations between radiographic features of knee osteoarthritis (OA) and pain have been demonstrated in persons with unilateral knee symptoms. This study was undertaken to compare radiographic and magnetic resonance imaging (MRI) features of knee OA and assess their ability to discriminate between painful and nonpainful knees in persons with unilateral symptoms.

METHODS

The study population included 283 individuals ages 70-79 years with unilateral knee pain who were enrolled in the Health, Aging, and Body Composition Study, a study of weight-related diseases and mobility. Radiographs of both knees were read for Kellgren/Lawrence (K/L) grade and individual radiographic features, and 1.5T MRIs were assessed using the Whole-Organ Magnetic Resonance Imaging Score. The association between structural features and pain was assessed using a within-person case-control design and conditional logistic regression. Receiver operating characteristic (ROC) analysis was then used to test the discriminatory performance of structural features.

RESULTS

In conditional logistic analyses, knee pain was significantly associated with both radiographic features (any joint space narrowing grade ≥ 1) (odds ratio 3.20 [95% confidence interval 1.79-5.71]) and MRI features (any cartilage defect scored ≥ 2) (odds ratio 3.67 [95% confidence interval 1.49-9.04]). However, in most subjects, MRI revealed osteophytes and cartilage and bone marrow lesions in both knees, and using ROC analysis, no individual structural feature discriminated well between painful and nonpainful knees. The best-performing MRI feature (synovitis/effusion) was not significantly more informative than K/L grade ≥ 2 (P = 0.42).

CONCLUSION

In persons with unilateral knee pain, MRI and radiographic features were associated with knee pain, confirming that structural abnormalities in the knee have an important role in the etiology of pain. However, no single MRI or radiographic finding performed well in discriminating between painful and nonpainful knees. Further work is needed to examine how structural and nonstructural factors influence knee pain.

Direct comparison of fixed flexion, radiography and MRI in knee osteoarthritis: responsiveness data from the Osteoarthritis Initiative

OBJECTIVE

Minimum radiographic joint space width (mJSW) represents the Food and Drug Administration (FDA) standard for demonstrating structural therapeutic benefits for knee osteoarthritis (KOA), but only shows moderate responsiveness (sensitivity to change). We directly compare the responsiveness of magnetic resonance imaging (MRI)-based cartilage thickness and JSW measures from fixed-flexion radiography (FFR) and explore the correlation of region-matched changes between both methods.

METHODS

Nine hundred and sixty-seven knees of Osteoarthritis Initiative participants with radiographic KOA were studied: 445 over 1 year with coronal FLASH MRI and FFR, and 375/522 over 1/2 years with sagittal DESS MRI and FFR. Standardized response means (SRM) of cartilage thickness and mJSW were compared using the sign-test.

RESULTS

With FLASH MRI, SRM was -0.28 for medial femorotibial compartment (MFTC) cartilage loss vs -0.15 for mJSW, and -0.32 vs -0.22 for the most sensitive MRI subregion (central MFTC) vs the most sensitive fixed-location JSW(x = 0.25). With DESS MRI, 1-year SRM was -0.34 for MFTC vs -0.22 for mJSW and -0.44 vs -0.28 for central MFTC vs JSW(x = 0.225). Over 2 years, the SRM was significantly greater for MFTC than for mJSW (-0.43 vs -0.31, P = 0.017) and for central MFTC than for JSW(x = 0.225) (-0.51 vs -0.44, P < 0.001). Correlations between changes in spatially matched MRI subregions and fixed-location JSW were not consistently higher (r = 0.10-0.51) than those between non-matched locations (r = 0.15-0.50).

CONCLUSIONS

MRI displays greater responsiveness in KOA than JSW FFR-based JSW, with the greatest SRM observed in the central medial femorotibial compartment. Fixed-location radiographic measures appear not capable of determining the spatial distribution of femorotibial cartilage loss.

Atlas-based knee cartilage assessment

Magnetic resonance imaging analysis of knee cartilage properties at corresponding anatomic locations could be a valuable tool in studies of knee osteoarthritis by enabling accurate comparisons at practically any region. A technique of this kind is presented in this study. The proposed technique is based on gray-level bone matching using affine transformations and free-form deformations thus eliminating the need of bone segmentations and landmark matching. Sixteen subjects of the osteoarthritis initiative with knee osteoarthritis (10 from baseline; 6 from 24-month follow-up) were included in this study. Baseline subjects were used to create a gray-level atlas of the patella with its corresponding mean cartilage thickness and T2 maps. Follow-up subjects were used to validate atlas-based point-to-point cartilage comparisons. All registrations were qualitatively evaluated with fused gray-level images of registered patellas. Quantitative evaluation was performed based on mean values of minimum Euclidean distances between matched bone-cartilage interfaces. A mean distance of 0.554 mm was obtained between the subjects used to build the atlas, and a mean distance of 0.633 mm was found between the atlas and validation subjects. The technique can be applied to other anatomical regions and with other cartilage measures. Qualitative and quantitative results demonstrate the accuracy of the technique and warrant its application in larger cross-sectional and longitudinal studies of osteoarthritis.

Quantitative cartilage imaging in knee osteoarthritis

Quantitative measures of cartilage morphology (i.e., thickness) represent potentially powerful surrogate endpoints in osteoarthritis (OA). These can be used to identify risk factors of structural disease progression and can facilitate the clinical efficacy testing of structure modifying drugs in OA. This paper focuses on quantitative imaging of articular cartilage morphology in the knee, and will specifically deal with different cartilage morphology outcome variables and regions of interest, the relative performance and relationship between cartilage morphology measures, reference values for MRI-based knee cartilage morphometry, imaging protocols for measurement of cartilage morphology (including those used in the Osteoarthritis Initiative), sensitivity to change observed in knee OA, spatial patterns of cartilage loss as derived by subregional analysis, comparison of MRI changes with radiographic changes, risk factors of MRI-based cartilage loss in knee OA, the correlation of MRI-based cartilage loss with clinical outcomes, treatment response in knee OA, and future directions of the field.

Alignment of the medial tibial plateau affects the rate of joint space narrowing in the osteoarthritic knee

OBJECTIVE

To determine, in serial fixed-flexion (FF) radiographs of subjects with knee osteoarthritis (KOA), the importance of, and basis for, the effect of alignment of the medial tibial plateau (MTP), as determined by the inter-margin distance (IMD), on joint space narrowing (JSN).

METHODS

Baseline and 12-month X-rays of 590 knees with Kellgren and Lawrence grade (KLG) 2/3 OA from the public-release dataset of the Osteoarthritis Initiative (OAI) were assigned to subgroups based upon IMD at baseline (IMD(BL)) and the difference between IMD(BL) and IMD(12 mos). Relationships of JSN to IMD(BL) and to the difference between IMD(BL and) IMD(12 mos) were evaluated.

RESULTS

In all 590 knees, mean JSN was 0.13 ± 0.51 mm (P<0.0001) and MTP alignment and replication of IMD(BL) in the 12-month film were, in general, poor. JSN was significantly (P=0.012) more rapid in Subgroup A (IMD≤1.70 mm at both time points) than in Subgroup B (both IMDs>1.70 mm): 0.15 ± 0.43; 0.08 ± 0.47. Within Subgroup B we identified a subset, Subgroup B1, in which, although alignment was poor at both time points, the large IMD(BL) was, by chance, highly reproduced by IMD(12 mos) (difference between the two IMDs=0.01 ± 0.27 mm, NS). JSN in Subgroup B1 was 0.06 ± 0.41 mm and did not differ from that in other knees of Subgroup B (P=0.87). The standardized response mean (SRM) in all 590 knees and Subgroups A, B and B1 was 0.25, 0.34, 0.17 and 0.06, respectively. Independent of IMD(BL), JSN correlated significantly with the difference between the IMDs in the two radiographs (r=0.17, P=0.0001).

CONCLUSION

Skewed MTP alignment in serial films and poor replication of IMD(BL) in the follow-up exam affect JSN measurement. The magnitude of change in joint space width (JSW) related to the poor quality of alignment that is common with the FF view jeopardizes accurate evaluation of JSN.

Multiplanar reconstruction recovers morphological cartilage assessment reproducibility from maloriented coronal MRI scans

The study's purpose was to assess the effect of multiplanar reconstruction on precision of weight-bearing medial and lateral femoral cartilage (cMF, cLF) morphometry in maloriented coronal MR images. Twenty knees were scanned four times with a 1.0 Tesla extremity imager using a fat-suppressed T1-weighted three-dimensional spoiled gradient recalled echo sequence; twice with "best as" double bull's-eye orientation of the femoral condyles, and once each with 5° internal and external rotation. Multiplanar reconstruction was applied to maloriented scans to recover double bull's-eye orientation. Medial and lateral femoral cartilages were segmented and precision of bone area, cartilage volume and thickness (ThCtAB) evaluated for all scans. Test-retest precision (RMSCV%) of the double bull's-eye scans was 1.1% for total bone area and 4.1% for cartilage volume. Differences in precision between double bull's-eye and maloriented images were assessed. Higher precision errors were observed in malorientated images for all outcomes (1.7-4.8% for internally rotation scans; 1.7-4.8% for external rotation scans). Precision generally improved with multiplanar reconstruction correction (1.7-5.6% for internally rotated scans; 1.2-3.5% for external rotation scans). Precision of femoral cartilage morphometry is generally reduced when maloriented images are acquired. Multiplanar reconstruction can correct malorientated scans and recover precision losses. Measurements are affected in a rotationally and compartmentally dependent manner.

Skin and urine pentosidine weakly correlate with joint damage in a cohort of patients with early signs of osteoarthritis (CHECK)

OBJECTIVES

Age-related changes in articular cartilage are likely to play a role in the aetiology of osteoarthritis (OA). One of the major age-related changes in cartilage is the accumulation of advanced-glycation-endproducts (AGEs). Since, cartilage tissue is not readily available from patients for studying AGE levels, alternative approaches such as analyzing skin and urine are needed to study the role of cartilage AGE levels in OA.

METHODS

Paired human skin and cartilage samples were obtained post mortem. Paired skin and urine samples were obtained from the CHECK cohort (early OA patients). Pentosidine levels were measured by high-performance liquid chromatography (HPLC). As marker of cumulative cartilage damage X-rays of both knees and hips were scored. Urinary CTXII (uCTXII) levels were measured, to assess current cartilage breakdown.

RESULTS

Cartilage and skin pentosidine correlate well (R=0.473, P=0.05). Skin pentosidine was higher in mild (summed (Kellgren & Lawrence K&L) over four large joints ≥4) compared to no (summed K&L≤3) radiographic OA (P=0.007). Urinary pentosidine was not different between these two groups. Skin pentosidine levels were not related to cartilage breakdown (highest vs lowest tertile of uCTXII). Urinary pentosidine, however, was higher in the highest compared to the lowest uCTXII tertile (P=0.009). Multiple regression analysis showed age to be the only predictor of the summed K&L score and age, creatinine clearance and urinary pentosidine as predictors of uCTXII.

CONCLUSION

The higher skin and urinary pentosidine levels in those with mild compared to no radiographic joint damage and low vs high cartilage breakdown respectively suggest that AGEs may contribute to disease susceptibility and/or progression. However, relations are weak and cannot be used as surrogate markers of severity of OA.

One-year change in radiographic joint space width in patients with unilateral joint space narrowing: data from the Osteoarthritis Initiative

OBJECTIVE

To examine the rate of joint space width (JSW) loss in both knees of patients with unilateral medial joint space narrowing (JSN) at baseline.

METHODS

Cases were selected from a pool of 2,678 subjects enrolled in the Osteoarthritis Initiative cohort. Inclusion criteria for the present study were unilateral medial JSN, bilateral frequent knee pain, and body mass index (BMI) > or = 25 kg/m(2). Baseline and 1-year fixed flexion radiographs of both knees were read (blinded to time point) using an automated algorithm for minimum JSW and JSW at 4 fixed locations in the medial compartment.

RESULTS

Sixty-seven participants met the inclusion criteria: 43 women and 24 men, with mean +/- SD age 60 +/- 9 years and mean +/- SD BMI 31 +/- 4 kg/m(2). Thirty-seven subjects (55%) had > or = 1 definite tibiofemoral osteophyte. The average progression in no-JSN knees was comparable with that in JSN knees (approximately -0.2 mm/year). However, JSW change was more variable in no-JSN knees, resulting in standardized response means (SRMs; the mean/SD) of approximately -0.24 in no-JSN knees versus approximately -0.41 in JSN knees on average at the 4 fixed locations, and SRMs of -0.24 and -0.35, respectively, for minimum JSW. Young age and high BMI were associated with increased progression, especially in JSN knees.

CONCLUSION

JSN and no-JSN knees progressed at a comparable rate, but a wider distribution of JSW change in no-JSN knees resulted in a poorer sensitivity to change in these knees.

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.

Magnetic resonance imaging-based cartilage loss in painful contralateral knees with and without radiographic joint space narrowing: Data from the Osteoarthritis Initiative

OBJECTIVE

To determine by magnetic resonance imaging (MRI), whether knees with advanced radiographic disease (medial joint space narrowing [mJSN]) encounter greater longitudinal cartilage loss than contralateral knees with earlier disease (no or less mJSN).

METHODS

Participants were selected from 2,678 cases in the Osteoarthritis Initiative, based on exhibition of bilateral pain, body mass index >25 (kg/m(2)), mJSN in 1 knee, no or less mJSN in the contralateral knee, and no lateral JSN in both knees. Eighty participants (mean +/- SD age 60.6 +/- 9.1 years) fulfilled these criteria. Medial tibial and femoral cartilage morphology was analyzed from the baseline and the 1-year followup MRI (sagittal double echo at steady state by 3.0T) of both knees by experienced readers blinded to the time point and mJSN status.

RESULTS

Knees with more radiographic mJSN displayed greater medial cartilage loss (-80 mum) assessed by MRI than contralateral knees with less mJSN (-57 mum). The difference reached statistical significance in participants with an mJSN grade of 2 or 3 (P = 0.005-0.08), but not in participants with an mJSN grade of 1 (P = 0.28-0.98). In knees with more mJSN, cartilage loss increased with higher grades of mJSN (P = 0.003 in the medial femur). Knees with an mJSN grade of 2 or 3 displayed greater cartilage loss in the weight-bearing medial femur than in the posterior femur or in the medial tibia (P = 0.048).

CONCLUSION

Knees with advanced mJSN displayed greater cartilage loss than contralateral knees with less mJSN. These data suggest that radiography can be used to stratify fast structural progressors, and that MRI cartilage thickness loss is more pronounced at advanced radiographic disease stage.

Occupational kneeling and radiographic tibiofemoral and patellofemoral osteoarthritis

BACKGROUND

The objective of our study was to evaluate the association between occupational kneeling and compartment specific radiographic tibiofemoral (TF) and patellofemoral (PF) osteoarthritis (OA).

METHODS

Questionnaire data and bilateral knee radiographs were obtained in 134 male floor layers and 120 male graphic designers (referents). Weight-bearing radiographs in three views (postero-anterior, lateral and axial) were classified according to joint space narrowing. After the exclusion of subjects with reports of earlier knee injuries the odds ratio (OR) with 95% confidence intervals (CI) of TF and PF OA was computed among floor layers compared to graphic designers in three age groups (</= 49; 50-59; >/= 60 years). Using logistic regression, estimates were adjusted for body mass index and knee-straining sports. In addition, the association between trade seniority and TF OA was assessed in age-adjusted test for trend analyses.

RESULTS

The prevalence of TF OA was significantly higher among floor layers aged 50-59 years compared to graphic designers (OR = 3.6, 95% CI = 1.1-12.0) while non-significant estimates were found in the young and elderly age groups. Furthermore, the adjusted OR of TF OA increased with trade seniority among floor layers (test for trend, OR = 2.2, 95% CI = 1.0-5.1), but not among graphic designers (OR = 1.2, 95% CI = 0.4-3.5). There were no significant differences regarding PF OA between the two occupational groups.

CONCLUSION

Results corroborate the existence of a causal relationship between occupational kneeling and radiographic TF OA and suggest a dose-response association with trade seniority. An association between kneeling and PF OA was however doubtful. Apparent discrepancies between findings in different age groups are most likely reflecting selection bias.

Reproducibility and sensitivity to change of a new method of computer measurement of joint space width in hip osteoarthritis. Performance of three radiographic views obtained at a 3-year interval

BACKGROUND

Measurement of radiographic joint space width (JSW) and of joint space narrowing (JSN) is the currently recommended method for assessment of anatomical severity and structural progression of osteoarthritis (OA), respectively. A standard radiographic view of the pelvis is commonly used for measurement of hip OA but other views are available.

OBJECTIVES

To evaluate the inter-intra reader reproducibility and the sensitivity to change of a new automated method of measurement of the hip JSW and to assess which radiographic view [pelvis anteroposterior (AP) view, hip AP view, hip oblique view] provides the greatest accuracy for JSW and JSN measurements.

MATERIAL AND METHODS

An AP pelvis radiograph, an AP radiograph centered on the target hip (AP hip) and an oblique view were performed at baseline (M0) and 3 years later (M36) in 50 hip OA patients. Two readers, blinded to each other's results and time sequence, measured twice, at a minimum 15 day interval, the six radiographs of each patient, using a novel version of a previously validated software program whose edge-based algorithm automatically detects the joint space contours. Inter-observer cross-sectional (M0+M36) and longitudinal (M0-M36) reproducibility of JSW measurement was assessed by the intra-class correlation coefficient (ICC) and the Bland-Altman method. Sensitivity to change was estimated by the standardized response mean (SRM). An ANOVA was used to analyze differences related to the observer and the view.

RESULTS

Intra-observer reproducibility: For JSW measurement, the ICC value, for observers 1 and 2 respectively, were 0.92 and 0.83 for the pelvic view, 0.96 and 0.88 for the hip AP view, and 0.90 and 0.86 for the oblique view. For JSN, ICC was 0.94 and 0.82 for the pelvic view, 0.97 and 0.78 for the hip AP view, and 0.95 and 0.86 for the oblique view. Inter-observer reproducibility: For JSW measurement, ICC was 0.87 for the pelvic view, 0.98 for the hip AP view, and 0.87 for the oblique view. The mean inter-observer difference (SD) was 0.0 (0.31), -0.01 (0.15) and -0.04 (0.4)mm for pelvic, AP and oblique views respectively. For JSN, ICC was 0.91 for the pelvic view, 0.93 for the hip AP view, and 0.90 for the oblique view. Sensitivity to change: SRM values were 0.61 (observer 1) and 0.65 (observer 2) for the pelvic view, 0.68 and 0.75, respectively, for the hip AP view, 0.64 and 0.66, respectively, for the oblique view. JSN did not vary significantly with the observer and the view. In 27% of cases intervention by the observer was necessary to correct the computer's identification of the acetabular edge in the area of interest.

CONCLUSION

Computer measurement of the radiographic hip joint space provided good intra- and inter-observer reproducibility and good sensitivity to change. However, it was necessary for the observer to intervene frequently to select the area of interest and adjust detection of the bone edge. The hip AP view performed better than the pelvis and oblique views, but not significantly so.

Location specific radiographic joint space width for osteoarthritis progression

OBJECTIVE

To establish the performance of location specific computer measures of radiographic joint space width (JSW) compared to measurements of minimum joint space width (mJSW) for the assessment of medial compartment knee osteoarthritis (OA). The study also investigated the most disease-responsive location for measuring medial compartment JSW.

METHODS

Serial bilateral Posterior Anterior (PA) conventional radiographs acquired with a fixed flexion protocol were obtained 36 months apart in 118 persons with knee OA participating in the Health, Aging and Body Composition (Health ABC) Study. Measurements of medial compartment mJSW and JSW at seven fixed locations were facilitated by the use of semi-automated software that delineated the femoral and tibial margins of the joint. A human reader operated custom software to verify and correct the software-drawn margins where necessary. Paired images were displayed with the reader blinded to the chronological order. The amount of joint space narrowing was measured and the standardized response mean (SRM) was used as a metric to quantify performance.

RESULTS

For all subjects, the mJSW SRM value was 0.42 while, for the most responsive location specific measure of JSW, it was SRM=0.46. For subjects with a Kellgren-Lawrence (KL) score less than or equal to 1, mJSW (SRM=0.40) was more responsive than the new measures (Maximum SRM=0.30). For KL=2or3, SRM=0.49 for mJSW, and SRM=0.74 for the most responsive location specific measure of JSW. Improved responsiveness was observed in the more central portion of the joint on the more diseased knees.

CONCLUSIONS

Location specific computer measures of JSW are feasible and potentially provide a superior method to assess radiographic OA for more diseased subjects. This new measure has the potential to improve the power of clinical studies that use a fixed flexion protocol.

Regional analysis of femorotibial cartilage loss in a subsample from the Osteoarthritis Initiative progression subcohort

OBJECTIVE

The Osteoarthritis Initiative (OAI) is aimed at validating (imaging) biomarkers for monitoring progression of knee OA. Here we analyze regional femorotibial (FT) cartilage thickness changes over 1 year using 3 Tesla MRI. Specifically, we tested whether changes in central subregions exceed those in the total cartilage plates.

METHODS

The right knees of a subsample of the OAI progression subcohort (n=156, age 60.9+/-9.9 years) were studied. Fifty-four participants had definite radiographic osteoarthritis (OA) (KLG 2 or 3) and a BMI>30. Mean and minimal cartilage thickness were determined in subregions of the medial/lateral tibia (MT/LT), and of the medial/lateral weight-bearing femoral condyle (cMF/cLF), after paired (baseline, follow up) segmentation of coronal FLASHwe images with blinding to the order of acquisition.

RESULTS

The central aspect of cMF displayed a 5.8%/2.8% change in mean thickness in the group of 54/156 participants, respectively, with a standardized response mean (SRM) of -0.47/-0.31, whereas cartilage loss in the total cMF was 4.1%/1.9% (SRM -0.49/-0.30). In the central MT, the rate of change was -1.6%/-0.9% and the SRM -0.29/-0.20, whereas for the entire MT the rate was -1.0%/-0.5% and the SRM -0.21/-0.12. Minimal thickness displayed greater rates of change, but lower SRMs than mean thickness.

CONCLUSIONS

This study shows that the rate of cartilage loss is greater in central subregions than in entire FT cartilage plates. The sensitivity to change in central subregions was higher than for the total cartilage plate in the MT and was similar to the total plate in the medial weight-bearing femur.

Performance of a non-fluoroscopically assisted substitute for the Lyon schuss knee radiograph: quality and reproducibility of positioning and sensitivity to joint space narrowing in osteoarthritic knees

OBJECTIVE

This study evaluated the longitudinal performance of a modified Lyon schuss (LS) knee examination in the detection of radiographic joint space narrowing (JSN) in knees with osteoarthritis (OA). The modified LS exam entails two to four iterative acquisitions with empirically adjusted angulation of the X-ray beam to achieve superimposition of the anterior and posterior margins of the medial tibial plateau (MTP), a marker of parallel radioanatomic alignment that the original LS exam achieves with fluoroscopically guided beam angulation.

METHODS

Seventy-four obese women with symptomatic knee OA underwent LS and fixed-flexion (FF, caudal 10 degrees beam angulation) X-ray exams at baseline and 1 year later. For 47 subjects, beam angulation for both LS exams was guided by fluoroscopy. For 27 subjects, the modified LS exam was performed at one or both times. Modified and original LS procedures were evaluated relative to concurrent FF radiographs with respect to the inter-margin distance (IMD) at the MTP midpoint (quality and reproducibility of alignment) and sensitivity to JSN.

RESULTS

Compared to FF radiographs, modified LS radiographs afforded a smaller mean IMD at baseline (0.89 vs 2.06 mm, P=0.002), more reproducible IMD (mean change=0.49 vs 0.91 mm, P=0.007) and more rapid JSN (mean=0.25 vs 0.02 mm/yr, P=0.005). These differences paralleled those observed between original LS and FF procedures with respect to baseline alignment (0.96 vs 1.94 mm, P<0.001), reproducibility of alignment (0.49 vs 1.00 mm, P<0.001) and sensitivity to JSN (0.16 vs -0.01 mm/yr, P=0.007).

CONCLUSION

In clinical centers where the absence of fluoroscopy equipment precludes use of the original LS protocol, a modified procedure employing iterative, empirical adjustment of the beam angle to achieve parallel radioanatomic alignment with the MTP affords a degree of superiority over the FF protocol with respect to quality and reproducibility of positioning and sensitivity to JSN in OA knees similar to that of the original.

Novel contrast mechanisms at 3 Tesla and 7 Tesla

Osteoarthritis (OA) is the most common musculoskeletal degenerative disease, affecting millions of people. Although OA has been considered primarily a cartilage disorder associated with focal cartilage degeneration, it is accompanied by well-known changes in subchondral and trabecular bone, including sclerosis and osteophyte formation. The exact cause of OA initiation and progression remains under debate, but OA typically first affects weightbearing joints such as the knee. Magnetic resonance imaging (MRI) has been recognized as a potential tool for quantitative assessment of cartilage abnormalities due to its excellent soft tissue contrast. Over the last two decades, several new MR biochemical imaging methods have been developed to characterize the disease process and possibly predict the progression of knee OA. These new MR biochemical methods play an important role not only for diagnosis of disease at an early stage, but also for their potential use in monitoring outcome of various drug therapies (success or failure). Recent advances in multicoil radiofrequency technology and high field systems (3 T and above) significantly improve the sensitivity and specificity of imaging studies for the diagnosis of musculoskeletal disorders. The current state-of-the-art MR imaging methods are briefly reviewed for the quantitative biochemical and functional imaging assessment of musculoskeletal systems.

The effect of glucosamine and/or chondroitin sulfate on the progression of knee osteoarthritis: a report from the glucosamine/chondroitin arthritis intervention trial

OBJECTIVE

Osteoarthritis (OA) of the knee causes significant morbidity and current medical treatment is limited to symptom relief, while therapies able to slow structural damage remain elusive. This study was undertaken to evaluate the effect of glucosamine and chondroitin sulfate (CS), alone or in combination, as well as celecoxib and placebo on progressive loss of joint space width (JSW) in patients with knee OA.

METHODS

A 24-month, double-blind, placebo-controlled study, conducted at 9 sites in the United States as part of the Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT), enrolled 572 patients with knee OA who satisfied radiographic criteria (Kellgren/Lawrence [K/L] grade 2 or grade 3 changes and JSW of at least 2 mm at baseline). Patients with primarily lateral compartment narrowing at any time point were excluded. Patients who had been randomized to 1 of the 5 groups in the GAIT continued to receive glucosamine 500 mg 3 times daily, CS 400 mg 3 times daily, the combination of glucosamine and CS, celecoxib 200 mg daily, or placebo over 24 months. The minimum medial tibiofemoral JSW was measured at baseline, 12 months, and 24 months. The primary outcome measure was the mean change in JSW from baseline.

RESULTS

The mean JSW loss at 2 years in knees with OA in the placebo group, adjusted for design and clinical factors, was 0.166 mm. No statistically significant difference in mean JSW loss was observed in any treatment group compared with the placebo group. Treatment effects on K/L grade 2 knees, but not on K/L grade 3 knees, showed a trend toward improvement relative to the placebo group. The power of the study was diminished by the limited sample size, variance of JSW measurement, and a smaller than expected loss in JSW.

CONCLUSION

At 2 years, no treatment achieved a predefined threshold of clinically important difference in JSW loss as compared with placebo. However, knees with K/L grade 2 radiographic OA appeared to have the greatest potential for modification by these treatments.

The long-term consequence of anterior cruciate ligament and meniscus injuries: osteoarthritis

The objectives of this study are to review the long-term consequences of injuries to the anterior cruciate ligament and menisci, the pathogenic mechanisms, and the causes of the considerable variability in outcome. Injuries of the anterior cruciate ligament and menisci are common in both athletes and the general population. At 10 to 20 years after the diagnosis, on average, 50% of those with a diagnosed anterior cruciate ligament or meniscus tear have osteoarthritis with associated pain and functional impairment: the young patient with an old knee. These individuals make up a substantial proportion of the overall osteoarthritis population. There is a lack of evidence to support a protective role of repair or reconstructive surgery of the anterior cruciate ligament or meniscus against osteoarthritis development. A consistent finding in a review of the literature is the often poor reporting of critical study variables, precluding data pooling or a meta-analysis. Osteoarthritis development in the injured joints is caused by intra-articular pathogenic processes initiated at the time of injury, combined with long-term changes in dynamic joint loading. Variation in outcome is reinforced by additional variables associated with the individual such as age, sex, genetics, obesity, muscle strength, activity, and reinjury. A better understanding of these variables may improve future prevention and treatment strategies. In evaluating medical treatment, we now expect large randomized clinical trials complemented by postmarketing monitoring. We should strive toward a comparable level of quality of evidence in surgical treatment of knee injuries. In instances in which a randomized clinical trial is not feasible, natural history and other observational cohort studies need to be as carefully designed and reported as the classic randomized clinical trial, to yield useful information.

Imaging of knee osteoarthritis: data beyond the beauty

PURPOSE OF REVIEW

MRI has revolutionized osteoarthritis research by providing semi-quantitative and quantitative imaging endpoints on most articular tissues. With the first image data of the Osteoarthritis Initiative now becoming publicly available, this article reviews recent developments in quantitative imaging of osteoarthritis.

RECENT FINDINGS

Although radiography remains the standard for regulatory studies on disease modifying osteoarthritis drugs, there is no consensus on the optimal positioning and acquisition protocol. With MRI, semi-quantitative scoring systems for evaluation of multiple articular tissue changes have been developed and are currently investigated in the context of correlation with symptoms and of predicting structural progression of osteoarthritis. Most efforts on quantitative measurement of imaging endpoints have focused on cartilage morphology and composition, with higher field strength (3T), newer sequences, and new measurement endpoints being a driver of current innovation.

SUMMARY

The semi-quantitative and quantitative tools for analysis of articular structure are now available and permit comprehensive analysis of morphological and compositional tissue changes in osteoarthritis. These changes will need to be related to clinical outcomes (e.g. how a patient feels or functions) with current epidemiological studies, such as the Osteoarthritis Initiatives, providing the opportunity for clinical validation of these imaging biomarkers.

Risk factors for early radiographic changes of tibiofemoral osteoarthritis

OBJECTIVE

To evaluate the risk factors for early radiographic changes of knee osteoarthritis.

METHODS

SUBJECTS

(n = 114) with unilateral or bilateral grade 0-1 knee osteoarthritis underwent x ray examination of the knees (semiflexed anteroposterior view) and assessment with the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index at baseline and 30 months later. Severity of joint space narrowing (JSN) and osteophytosis were graded in randomly ordered serial radiographs by two readers, blinded to the sequence of the films, using standard pictorial atlases.

RESULTS

The odds of an initial appearance of radiographic features of knee osteoarthritis at month 30 were more than threefold greater in African Americans than in whites (osteophytosis: odds ratio (OR) 3.30, 95% confidence interval (CI) 1.04 to 10.54; JSN: OR 3.49, 95% CI 1.16 to 10.68). In addition, the appearance of osteophytosis was positively related to baseline stiffness (OR 1.91/2.1 points on the 2-10 WOMAC scale, 95% CI 1.29 to 2.82).

CONCLUSIONS

The distinction between incident and established, but early, radiographic knee osteoarthritis is difficult because of the limits to which all possible evidence of the disease can be ruled out in a conventional baseline knee radiograph. Nonetheless, our finding that African Americans were at greater risk of early osteophytosis and JSN than other subjects differs from the results of our previous analysis of risk factors for progressive knee osteoarthritis in the same subjects. The development of osteophytes also was associated with joint stiffness. Future investigations should focus on the systemic and local influences that these ostensible risk factors represent.