Osteoarthritis: current role of imaging

Prevalence of Clinically Relevant Findings on Magnetic Resonance Imaging in Middle-Aged Adults With Knee Pain and Suspected Meniscal Tear: A Follow-Up

OBJECTIVE

Radiographs are frequently obtained for patients with knee osteoarthritis (KOA), with magnetic resonance imaging (MRI) reserved for those with complex KOA. There are few data on how often subsequent MRI reveals clinically actionable but unanticipated findings. The purpose of this study is to estimate the prevalence of these findings on MRI for patients managed nonoperatively for suspected meniscal tears.

METHODS

The Treatment of Meniscal Problems and Osteoarthritis (TeMPO) study enrolled patients aged 45 to 85 years with knee pain, osteoarthritis (Kellgren-Lawrence [KL] grades 0-3), and suspected meniscal tear. We reviewed baseline MRI and recorded notable findings, including subchondral insufficiency fractures of the knee (SIFKs), avascular necrosis (AVN), tumors, and nonsubchondral fractures. Other baseline data included demographic characteristics, Knee Injury and Osteoarthritis Outcome Score, duration of knee symptoms, and KL grade.

RESULTS

Study-ordered MRI was performed on 760 patients, with 61 concerning findings identified (8.03%, 95% confidence interval 6.09%-9.96%). A total of 25 participants had SIFKs, 10 had nonsubchondral fractures, 4 had AVN, 8 had benign tumors, and 14 had other clinically relevant findings.

CONCLUSION

We estimated the prevalence of clinically relevant incidental findings on MRI to be 8.03% in middle-aged adults with mild to moderate KOA and suspected meniscal tear. These data may prompt clinicians to be more aware of the range of findings that can underlie knee symptoms, some of which could change management but may require different modalities of imaging to detect. Future research is needed to pinpoint factors associated with these concerning findings so that patients who are at risk can be identified and referred for advanced imaging.

Survivorship and outcomes of intra- and perimeniscal corticosteroids injections with structured physiotherapy for degenerative medial meniscus tears

BACKGROUND

Degenerative medial meniscus tears are a common pathology in the general population. Recent randomized trials demonstrated non-superiority of arthroscopic partial meniscectomy over conservative management. However, there is a paucity of information regarding the outcomes of combined conservative treatments.

HYPOTHESIS

It was hypothesized that combined intra- and perimeniscal corticosteroid injections with structured physiotherapy, for degenerative medial meniscus tears, would result in high surgery-free and second injection-free survivorship.

METHODS

A retrospective review of 671 patients with symptomatic degenerative medial meniscus tears, who received intra- and perimeniscal corticosteroids injection combined with structured physiotherapy, was conducted. An ultrasound-guided injection of Triamcinolone Hexacetonide 20 mg/ml comprised; 1.5 ml intra-meniscal,1.5 ml in the meniscal wall, and 2 ml in the peri-meniscal space, was performed. Surgery free- and a second injection free-survivorship were analysed. Western Ontario and Macmaster University scores (WOMAC), Tegner activity scores, patient satisfaction, return-to-work status and average time to return to work were recorded.

RESULTS

A total of 481 patients who met the inclusion criteria were included. The mean age was 51.1 ± 7.9 years. At five years post-procedure, surgery-free, and second injection-free survivorship of the ipsilateral knee was 83%, and 52%, respectively. A multivariate analysis adjusting survival on parametric risk factors identified that only effusion before steroid injection was an independent risk factor of treatment failure. At a mean follow-up of 4 ± 2 years, there was an improvement in WOMAC scores by 5.2 ± 4.9 for pain, by 2 ± 2 for stiffness, by 7.3 ± 7.4 for function, and by 12.4 ± 12.7 for the global scores. Additionally, there was significant improvement in the Tegner activity scores (All p < 0.001). Knee effusion and advanced osteoarthritis (Kellgren-Lawrence > III) were significantly associated with poorer outcomes; p < 0.003 and p < 0.0004, respectively.

CONCLUSION

A combination of intra- and perimeniscal corticosteroid injections and structured physiotherapy for degenerative medial meniscus tears, results in high surgery-free (83%) and second injection-free (52%) survivorship, as well as, effective clinical outcomes and satisfaction at 5 years.

LEVEL OF EVIDENCE

IV; Retrospective Case Series.

Optimizing hip MRI: enhancing image quality and elevating inter-observer consistency using deep learning-powered reconstruction

BACKGROUND

Conventional hip joint MRI scans necessitate lengthy scan durations, posing challenges for patient comfort and clinical efficiency. Previously, accelerated imaging techniques were constrained by a trade-off between noise and resolution. Leveraging deep learning-based reconstruction (DLR) holds the potential to mitigate scan time without compromising image quality.

METHODS

We enrolled a cohort of sixty patients who underwent DL-MRI, conventional MRI, and No-DL MRI examinations to evaluate image quality. Key metrics considered in the assessment included scan duration, overall image quality, quantitative assessments of Relative Signal-to-Noise Ratio (rSNR), Relative Contrast-to-Noise Ratio (rCNR), and diagnostic efficacy. Two experienced radiologists independently assessed image quality using a 5-point scale (5 indicating the highest quality). To gauge interobserver agreement for the assessed pathologies across image sets, we employed weighted kappa statistics. Additionally, the Wilcoxon signed rank test was employed to compare image quality and quantitative rSNR and rCNR measurements.

RESULTS

Scan time was significantly reduced with DL-MRI and represented an approximate 66.5% reduction. DL-MRI consistently exhibited superior image quality in both coronal T2WI and axial T2WI when compared to both conventional MRI (p < 0.01) and No-DL-MRI (p < 0.01). Interobserver agreement was robust, with kappa values exceeding 0.735. For rSNR data, coronal fat-saturated(FS) T2WI and axial FS T2WI in DL-MRI consistently outperformed No-DL-MRI, with statistical significance (p < 0.01) observed in all cases. Similarly, rCNR data revealed significant improvements (p < 0.01) in coronal FS T2WI of DL-MRI when compared to No-DL-MRI. Importantly, our findings indicated that DL-MRI demonstrated diagnostic performance comparable to conventional MRI.

CONCLUSION

Integrating deep learning-based reconstruction methods into standard clinical workflows has the potential to the promise of accelerating image acquisition, enhancing image clarity, and increasing patient throughput, thereby optimizing diagnostic efficiency.

TRIAL REGISTRATION

Retrospectively registered.

Effect of Footwear Type on Biomechanical Risk Factors for Knee Osteoarthritis

BACKGROUND

Regular walking in different types of footwear may increase the mediolateral shear force, knee adduction moment, or vertical ground-reaction forces that could increase the risk of early development of knee osteoarthritis (OA).

PURPOSE

To compare kinematic and kinetic parameters that could affect the development of knee OA in 3 footwear conditions.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 40 asymptomatic participants performed walking trials in the laboratory at self-selected walking speeds under barefoot (BF), minimalistic (MF), and neutral (NF) footwear conditions. Knee joint parameters were described using discrete point values, and continuous curves were evaluated using statistical parametric mapping. A 3 × 1 repeated-measures analysis of variance was used to determine the main effect of footwear for both discrete and continuous data. To compare differences between footwear conditions, a post hoc paired t test was used.

RESULTS

Discrete point analyses showed a significantly greater knee power in NF compared with MF and BF in the weight absorption phase (P < .001 for both). Statistical parametric mapping analysis indicated a significantly greater knee angle in the sagittal plane at the end of the propulsive phase in BF compared with NF and MF (P = .043). Knee joint moment was significantly greater in the propulsive phase for the sagittal (P = .038) and frontal planes (P = .035) in BF compared with NF and MF and in the absorption phase in the sagittal plane (P = .034) in BF compared with MF and NF. A significant main effect of footwear was found for anteroposterior (propulsion, ↑MF, NF, ↓BF [P = .008]; absorption, ↑BF, MF, ↓NF [P = .001]), mediolateral (propulsion, ↑MF, NF, ↓BF [P = .005]; absorption, ↑NF, MF, ↓BF [P = .044]), and vertical (propulsion, ↑NF, BF, ↓MF [P = .001]; absorption, ↑MF, BF, ↓NF [P < .001]) ground-reaction forces. Knee power showed a significant main effect of footwear (absorption, ↑NF, MF, ↓BF [P = .015]; propulsion, ↑MF, NF, ↓BF [P = .039]).

CONCLUSION

Walking in MF without sufficient accommodation affected kinetic and kinematic parameters and could increase the risk of early development of knee OA.

Three-dimensional analysis for quantification of knee joint space width with weight-bearing CT: comparison with non-weight-bearing CT and weight-bearing radiography

OBJECTIVE

To compare computer-based 3D-analysis for quantification of the femorotibial joint space width (JSW) using weight-bearing cone beam CT (WB-CT), non-weight-bearing multi-detector CT (NWB-CT), and weight-bearing conventional radiographs (WB-XR).

DESIGN

Twenty-six participants prospectively underwent NWB-CT, WB-CT, and WB-XR of the knee. For WB-CT and NWB-CT, the average and minimal JSW was quantified by 3D-analysis of the minimal distance of any point of the subchondral tibial bone surface and the femur. Associations with mechanical leg axes and osteoarthritis were evaluated. Minimal JSW of WB-CT was further compared to WB-XR. Two-tailed p-values of <0.05 were considered significant.

RESULTS

Significant differences existed of the average medial and lateral JSW between WB-CT and NWB-CT (medial: 4.7 vs 5.1 mm [P = 0.028], lateral: 6.3 vs 6.8 mm [P = 0.008]). The minimal JSW on WB-XR (medial:3.1 mm, lateral:5.8 mm) were significantly wider compared to WB-CT and NWB-CT (both medial:1.8 mm, lateral:2.9 mm, all p < 0.001), but not significantly different between WB-CT and NWB-CT (all p ≥ 0.869). Significant differences between WB-CT and NWB-CT existed in participants with varus knee alignment for the average and the minimal medial JSW (p = 0.004 and p = 0.011) and for participants with valgus alignment for the average lateral JSW (p = 0.013). On WB-CT, 25% of the femorotibial compartments showed bone-on-bone apposition, which was significantly higher when compared to NWB-CT (10%,P = 0.008) and WB-XR (8%,P = 0.012).

CONCLUSION

Combining WB-CT with 3D-based assessment allows detailed quantification of the femorotibial joint space and the effect of knee alignment on JSW. WB-CT demonstrates significantly more bone-on-bone appositions, which are underestimated or even undetectable on NWB-CT and WB-XR.

Prevalence of Undiagnosed Subchondral Insufficiency Fractures of the Knee in Middle Age Adults with Knee Pain and Suspected Meniscal Tear

Objective

Symptomatic knee osteoarthritis (OA) and meniscal tear are often treated with weight-bearing exercises and without ordering advanced imaging (e.g. MRI). This may lead to missed diagnoses of subchondral insufficiency fracture of the knee (SIFK). Failure to diagnose SIFK has treatment implications, as patients with SIFK are typically managed with a period of reduced weight-bearing. The primary objective of this study is to determine the prevalence of undiagnosed SIFK among persons treated non-operatively for knee pain and suspected meniscal tear(s).

Methods

The randomized controlled trial, TeMPO (Treatment of Meniscal Problems and Osteoarthritis), enrolls subjects whose clinicians suspect concomitant meniscal tear and knee OA. TeMPO participants undergo MRI ordered by the study to confirm meniscal tear. All study-ordered MRIs revealing a fracture were reviewed by two study radiologists who noted features of the fracture and joint. We report prevalence of SIFK and clinical and imaging features on these subjects with 95% confidence intervals.

Results

Ten of the 340 study-ordered MRIs had SIFK, resulting in an estimated prevalence of 2.94% (95% CI: 1.15%, 4.71%). Eight of the ten participants with SIFK had fractures located medially. The femur was involved in five of these participants, tibia in four, and both in one. Five of the ten participants did not have meniscal tears.

Conclusions

This is the only reported estimate of undiagnosed SIFK in adults with knee pain, to our knowledge. Approximately 3% of patients managed with weight-bearing exercise for suspected meniscal tear may have SIFK, a diagnosis typically treated with reduced weight-bearing approaches.

Ultrasonography of Knee Joint in Hemophilia A: What the Eyes Cannot See

Haemophilia is the most common inherited coagulopathy. Approximately 94% patients suffer from joint disability. An imaging modality to detect joint damage can help in monitoring. Ultrasonography (USG) provides a low cost and reliable imaging alternative to magnetic resonance imaging. This study aims at the detection of subclinical knee-joint involvement by USG, in patients with moderate to severe Haemophilia. 27 patients suffering from moderate and severe Haemophilia and 27 age-matched controls were studied. USG of bilateral knee joints was done to analyse cartilage and synovial thickness, synovial vascularity and resistive index of vascular flow along with synovial collection. The relevant clinical parameters (age at diagnosis and study enrolment, severity of haemophilia A, annualized bleeding rates, total number of joint bleeds, spontaneous and provoked bleed, number of episodes treated with factor VIII injection) were noted. The USG findings were correlated to the clinical parameters and subclinical joint bleed detection looked for. 13 patients [18 out of 54 joints (33.33%)] showed increased vascular signals with mean resistive-index (RI) 0.67 (± 0.086; 95% CI: 0.62-0.70). The mean synovial thickness in persons with haemophilia (PwH) was higher than the control subset (p < 0.05 on all counts). The mean cartilage thickness was lower in PwH than in controls. On a subset analysis, there was significant difference between the mean cartilage thickness between moderate PwH and age matched controls (p < 0.0001). 3 patients (11.1%) showed evidence of joint collection (hemarthrosis) despite having no clinical evidence of joint involvement. Through the findings of our study, we do infer that ultrasonography can detect subclinical synovial inflammation and cartilage damage in haemophilia patients that may affect long term articular outcome. It is also a useful modality for detection of sub clinical joint bleed.

MRI of synovitis and joint fluid

Synovitis and joint effusion are common manifestations of rheumatic disease and play an important role in the disease pathophysiology. Earlier detection and accurate assessment of synovial pathology, therefore, can facilitate appropriate clinical management and hence improve prognosis. Magnetic resonance imaging (MRI) allows unparalleled assessment of all joint structures and associated pathology. It has emerged as a powerful tool, which enables not only detection of synovitis and effusion, but also allows quantification, detailed characterization, and noninvasive monitoring of synovial processes. The purpose of this article is to summarize the pathophysiology of synovitis and to review the role of qualitative, semiquantitative, and quantitative MRI in the assessment of synovitis and joint fluid. We also discuss the utility of MRI as an outcome measure to assess treatment response, particularly with respect to osteoarthritis and rheumatoid arthritis. Emerging applications such as hybrid positron emission tomography / MRI and molecular imaging are also briefly discussed. Level of Evidence: 5 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019.

Concurrent Assessment of Cartilage Morphology and Bone Microarchitecture in the Human Knee Using Contrast-Enhanced HR-pQCT Imaging

Osteoarthritis (OA) is a prevalent articular disease characterized by whole joint degradation, including articular cartilage and bone. Presently, no single imaging modality is well suited to concurrently capture these changes. Recent ex vivo animal studies have demonstrated the efficacy of utilizing contrast agents in conjunction with micro-CT as a means of evaluating cartilage and bone alterations concurrently, though no work as of yet has been performed in large animal models or humans. This study sought to develop and validate a novel joint imaging technique, contrast enhanced high resolution peripheral quantitative computed tomography (CEHR-pQCT), to concurrently assess bone microarchitecture and cartilage morphology in the whole human knee. Fresh frozen cadaveric knees were harvested (n = 10) and scanned using magnetic resonance imaging (MRI), HR-pQCT without contrast, and HR- pQCT following intra-articular injection of nonionic contrast media. Cartilage morphology and bone microarchitecture were evaluated in weight bearing regions of interest in both the tibia and femur. Joints were then disarticulated, and the articular cartilage thickness measured by needle probe. Measures of cartilage morphology, thickness and volume, were found to be significantly less when measured by CEHR- pQCT compared to magnetic resonance imaging in all regions. Compared to needle probing, cartilage thickness measured by CEHR-pQCT was less in the lateral tibia and greater in the medial tibia. Bone microarchitecture was found to be significantly different when measured with CEHR-pQCT compared to HR-pQCT, where cortical bone mineral density (BMD) was depressed, and trabecular bone mineral density was greater. This study demonstrates that CEHR-pQCT can be used to concurrently measure cartilage morphology and bone microarchitecture; however, systematic errors impact both measures. This is the first study using contrast media in combination with HR-pQCT in whole joints. Additionally, all imaging parameters, as well as the contrast media, were selected to be directly transferable to in vivo studies, laying the foundation to perform in vivo scanning of knee cartilage and bone.

Ultrasound guided injection of a painful knee osteoarthritis with medial meniscus extrusion: a case series study

Background

Meniscal subluxation results in the natural history of knee osteoarthritis (OA). Periarticular infiltration should minimize possible complications related to penetration of corticosteroids into the joint space in the treatment of knee OA.According to pain relief and improvement of function, the aim of this study is to evaluate the effectiveness of perimeniscal corticosteroid ultrasound guided injection in knee OA.

Methods

Thirty-two patients received an injection of 0.5 ml of methylprednisolone-acetate around perimeniscal tissues. Outcome measures were pain relief and knee function, assessed by Visual Analogue Scale (VAS) [24, 29, 30] measured at rest (VAS-R) and during stairs climbing (VAS-C) and by Italian-Western Ontario and McMaster Universities (WOMAC) scale. Clinical evaluation was performed at baseline, at 1 and 4 weeks of follow-up.

Results

Mean baseline values of VAS-R and VAS-C were 6.79 ± 1.17 and 7.6 ± 1.39, respectively. All subjects showed a significant reduction in pain over time (p<0.001). Mean baseline values of WOMAC pain, stiffness and physical function were 5.56 ± 1.32, 4.39 ± 1.91 and 4.63 ± 2.31, respectively. According to WOMAC stiffness and physical function was not found a significant improvement over time (p> 0.05).

Conclusion

Corticosteroid perimeniscal ultrasound guided injection can be considered as an adjunct to core treatment for the relief of moderate to severe pain in people with knee OA.

Level of Evidence

IV.

Therapeutic effects of low-frequency phonophoresis with a Chinese herbal medicine versus sodium diclofenac for treatment of knee osteoarthritis: a double-blind, randomized, placebo-controlled clinical trial

OBJECTIVE

To evaluate the therapeutic effects of low-frequency phonophoresis with a Chinese herbal medicine (CHM) compared with sodium diclofenac (SD) for knee osteoarthritis (KOA).

METHODS

In this double-blind, randomized, placebo-controlled trial, 100 KOA patients were assigned randomly to a placebo group, a CHM group, or SD group. Low-frequency phonophoresis was used to improve the efficiency of drug delivery. Pain at rest [using a visual analog scale (VAS)], pain on movement (VAS), and range of motion (degrees) in the three groups were evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMACAI) scores. Safety assessments comprised emergency adverse events, as well as laboratory tests of blood biochemistry, creatinine, blood urea nitrogen, alanine aminotransferase and aspartate aminotransferase.

RESULTS

Significant improvements were found after treatment in all outcome measures except stiffness and range of motion in patients in the CHMP group and SDP group (P < 0.05). No significant differences in all outcome measures were found between the CHMP group and SDP group.

CONCLUSION

CHMP and SDP can show good therapeutic effects for KOA in terms of relieving pain and improving physical function.

Reliability of a Proposed Ultrasonographic Grading Scale for Severity of Primary Knee Osteoarthritis

OBJECTIVES

The objective of this study was to examine the concordance of a grading scale (0–4) of medial femoral osteophytes in knee joint detected by ultrasound (US) compared with the corresponding grades (0–4) of Kellgren–Lawrence (K&L) scale of conventional radiography and clinical joint examination.

PATIENTS AND METHODS

A cross-sectional observational study included 160 patients with knee pain who fulfilled the American College of Rheumatology (ACR) criteria for knee osteoarthritis (KOA) and 20 patients with knee pain who have not fulfilled the ACR criteria for KOA. All patients were subjected to clinical assessment (Western Ontario and McMaster Universities Index of Osteoarthritis and global visual analog scale) and radiological assessment in the form of X-ray grading according to K&L grading scale and ultrasonographic assessment of medial femoral osteophytes according to a scale that was proposed by the first author and consisted of five grades (0–4), where grade 0 denoted no osteoarthritis and grade 4 denoted the most advanced grade of KOA. Grade 2 was divided into two subgrades A and B with grade 2B considered as a more advanced stage than grade 2A.

RESULTS

The proposed US grading scale had high sensitivity and specificity in detecting the different grades of KOA compared with K&L grading scale (a total sensitivity of 94.6% and a total specificity of 93.3%). Intra- and interreader reliability of US was excellent (kappa >0.93 and >0.85, respectively).

CONCLUSIONS

US can reliably detect the severity of KOA. Good agreement was found between the proposed US grading scale and K&L grading scale. The proposed US grading scale is simple and reliable.

In-vitro and in-vivo imaging of MMP activity in cartilage and joint injury

Non-destructive detection of cartilage-degrading activities represents an advance in osteoarthritis (OA) research, with implications in studies of OA pathogenesis, progression, and intervention strategies. Matrix metalloproteinases (MMPs) are principal cartilage degrading enzymes that contribute to OA pathogenesis. MMPSense750 is an in-vivo fluorimetric imaging probe with the potential to continuously and non-invasively trace real-time MMP activities, but its use in OA-related research has not been reported. Our objective is to detect and characterize the early degradation activities shortly after cartilage or joint injury with MMPSense750. We determined the appropriate concentration, assay time, and linear range using various concentrations of recombinant MMPs as standards. We then quantified MMP activity from cartilage explants subjected to either mechanical injury or inflammatory cytokine treatment in-vitro. Finally, we performed in-vivo MMP imaging of a mouse model of post-traumatic OA. Our in-vitro results showed that the optimal assay time was highly dependent on the MMP enzyme. In cartilage explant culture media, mechanical impact or cytokine treatment increased MMP activity. Injured knees of mice showed significantly higher fluorescent signal than uninjured knees. We conclude that MMPSense750 detects human MMP activities and can be used for in-vitro study with cartilage, as well as in-vivo studies of knee injury, and can offering real-time insight into the degradative processes that occurring within the joint before structural changes become evident radiographically.

Imaging of non-osteochondral tissues in osteoarthritis

OBJECTIVE

The aim of this review is to describe imaging techniques for evaluation of non-osteochondral structures such as the synovium, menisci in the knee, labrum in the hip, ligaments and muscles and to review the literature from recent clinical and epidemiological studies of OA.

METHODS

This is a non-systematic narrative review of published literature on imaging of non-osteochondral tissues in OA. PubMed and MEDLINE search for articles published up to 2014, using the keywords osteoarthritis, synovitis, meniscus, labrum, ligaments, plica, muscles, magnetic resonance imaging (MRI), ultrasound, computed tomography (CT), scintigraphy, and positron emission tomography (PET).

RESULTS

Published literature showed imaging of non-osteochondral tissues in OA relies primarily on MRI and ultrasound. The use of semiquantitative and quantitative imaging biomarkers of non-osteochondral tissues in clinical and epidemiological OA studies is reported. We highlight studies that have compared both imaging methodologies directly, and those that have established a relationship between imaging biomarkers and clinical outcomes. We provide recommendations as to which imaging protocols should be used to assess disease-specific changes regarding synovium, meniscus in the knee, labrum in the hip, and ligaments, and highlight potential pitfalls in their usage.

CONCLUSION

MRI and ultrasound are currently the most useful imaging modalities for evaluation of non-osteochondral tissues in OA. MRI evaluation of any tissue needs to be performed using appropriate MR pulse sequences. Ultrasound may be particularly useful for evaluation of small joints of the hand. Nuclear medicine and CT play a limited role in imaging of non-osteochondral tissues in OA.

Population prevalence of ultrasound features of osteoarthritis in the hand, knee and hip at age 63 years: the Newcastle thousand families birth cohort

Background

Musculoskeletal ultrasound has been found to be more sensitive than radiographs in detecting osteophytes. Our objective was to measure the prevalence of features of osteoarthritis (OA), in the dominant hand, knees and hips using ultrasound, within the Newcastle Thousand Families birth cohort.

Methods

Participants were aged 61–63 (mean 63) years. Knee images were scored for presence of osteophytes and effusion. Hip images were scored for the presence of osteophytes and femoral head abnormality. The first carpometacarpal joint, metacarpophalangeal, proximal interphalangeal and distal interphalangeal joints of the index finger (dominant hand) were imaged for osteophytes.

Results

Among 311 participants, prevalence of osteophytes at the distal interphalangeal joint was 70% while it was 23%, 10% and 41% for index proximal interphalangeal and metacarpophalangeal and thumb base carpometacarpal joints respectively. Prevalence of knee osteophytes was 30%, hip OA was 41%. Prevalence of knee effusions was 24% (right) and 20% (left). Ultrasound evidence of generalised OA (48%) and isolated hand OA (31%) was common, compared to isolated hip or knee OA (5%) and both hip and knee OA (3%).

Conclusion

This is the first study to assess prevalence of ultrasound features of OA in a population-based sample. The higher prevalence of hand/hip OA, when compared to previous radiographic studies, supports the hypothesis that ultrasound is more sensitive than radiography in detecting OA, particularly for osteophytes.

Strength Training for Arthritis Trial (START): design and rationale

Background

Muscle loss and fat gain contribute to the disability, pain, and morbidity associated with knee osteoarthritis (OA), and thigh muscle weakness is an independent and modifiable risk factor for it. However, while all published treatment guidelines recommend muscle strengthening exercise to combat loss of muscle mass and strength in knee OA patients, previous strength training studies either used intensities or loads below recommended levels for healthy adults or were generally short, lasting only 6 to 24 weeks. The efficacy of high-intensity strength training in improving OA symptoms, slowing progression, and affecting the underlying mechanisms has not been examined due to the unsubstantiated belief that it might exacerbate symptoms. We hypothesize that in addition to short-term clinical benefits, combining greater duration with high-intensity strength training will alter thigh composition sufficiently to attain long-term reductions in knee-joint forces, lower pain levels, decrease inflammatory cytokines, and slow OA progression.

Methods/Design

This is an assessor-blind, randomized controlled trial. The study population consists of 372 older (age ≥ 55 yrs) ambulatory, community-dwelling persons with: (1) mild-to-moderate medial tibiofemoral OA (Kellgren-Lawrence (KL) = 2 or 3); (2) knee neutral or varus aligned knee ( -2° valgus ≤ angle ≤ 10° varus); (3) 20 kg^.m^-2 ≥ BMI ≤ 45 kg^.m^-2; and (3) no participation in a formal strength-training program for more than 30 minutes per week within the past 6 months. Participants are randomized to one of 3 groups: high-intensity strength training (75-90% 1Repetition Maximum (1RM)); low-intensity strength training (30-40%1RM); or healthy living education. The primary clinical aim is to compare the interventions’ effects on knee pain, and the primary mechanistic aim is to compare their effects on knee-joint compressive forces during walking, a mechanism that affects the OA disease pathway. Secondary aims will compare the interventions’ effects on additional clinical measures of disease severity (e.g., function, mobility); disease progression measured by x-ray; thigh muscle and fat volume, measured by computed tomography (CT); components of thigh muscle function, including hip abductor strength and quadriceps strength, and power; additional measures of knee-joint loading; inflammatory and OA biomarkers; and health-related quality of life.

Discussion

Test-retest reliability for the thigh CT scan was: total thigh volume, intra-class correlation coefficients (ICC) = 0.99; total fat volume, ICC = 0.99, and total muscle volume, ICC = 0.99. ICC for both isokinetic concentric knee flexion and extension strength was 0.93, and for hip-abductor concentric strength was 0.99. The reliability of our 1RM testing was: leg press, ICC = 0.95; leg curl, ICC = 0.99; and leg extension, ICC = 0.98. Results of this trial will provide critically needed guidance for clinicians in a variety of health professions who prescribe and oversee treatment and prevention of OA-related complications. Given the prevalence and impact of OA and the widespread availability of this intervention, assessing the efficacy of optimal strength training has the potential for immediate and vital clinical impact.

Trial registration

ClinicalTrials.gov, NCT01489462

Application of advanced magnetic resonance imaging techniques in evaluation of the lower extremity

This article reviews current magnetic resonance imaging (MR imaging) techniques for imaging the lower extremity, focusing on imaging of the knee, ankle, and hip joints. Recent advancements in MR imaging include imaging at 7 T, using multiple receiver channels, T2* imaging, and metal suppression techniques, allowing more detailed visualization of complex anatomy, evaluation of morphologic changes within articular cartilage, and imaging around orthopedic hardware.

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.

High resolution micro arthrography of hard and soft tissues in a murine model

OBJECTIVE

Recent developments on high resolution micro computed tomography (μCT) allow imaging of soft tissues in small animal joints. Nevertheless, μCT images cannot distinguish soft tissues from synovial fluid due to their similar mass density, limiting the 3D assessment of soft tissues volume and thickness. This study aimed to evaluate a lead chromate contrast agent for μCΤ arthrography of rat knee joints ex vivo.

DESIGN

Intact tibiofemoral rat joints were injected with the contrast agent at different concentrations and imaged using a μCT at 2.7 μm isotropic voxel size. Cartilage thickness was measured using an automated procedure, validated against histological measurements, and analyzed as a function of μCT image resolution. Changes in hard and soft tissues were also analyzed in tibiofemoral joints 4 weeks after surgical destabilization of the medial meniscus (DMM).

RESULTS

The contrast agent diffused well throughout the whole knee cavity without penetrating the tissues, therefore providing high contrast at the boundaries between soft tissues and synovial fluid space. Thickness analysis of cartilage demonstrated a high similarity between histology and μ-arthrography approaches (R(2) = 0.90). Four weeks after surgical DMM, the development of osteophytes (Oph) and cartilage ulcerations was recognizable with μCT, as well as a slight increase in trabecular bone porosity, and decrease in trabecular thickness.

CONCLUSIONS

A lead chromate-based contrast agent allowed discriminating the synovial fluid from soft tissues of intact knee joints, and thus made possible both qualitative and quantitative assessment of hard and soft tissues in both intact and DMM tibiofemoral joints using high resolution μCT.

Diagnosis of osteoarthritis: imaging

Osteoarthritis (OA) is a chronic, debilitating joint disease characterized by degenerative changes to the bones, cartilage, menisci, ligaments, and synovial tissue. Imaging modalities such as radiography, magnetic resonance imaging (MRI), optical coherence tomography (OCT), and ultrasound (US) permit visualization of these structures and can evaluate disease onset and progression. Radiography is primarily useful for the assessment of bony structures, while OCT is used for evaluation of articular cartilage and US for ligaments and the synovium. MRI permits visualization of all intraarticular structures and pathologies, though US or OCT may be preferential in some circumstances. As OA is a disease of the whole joint, a combination of imaging techniques may be necessary in order to gain the most comprehensive picture of the disease state. This article is part of a Special Issue entitled "Osteoarthritis".

Unsupervised segmentation and quantification of anatomical knee features: data from the Osteoarthritis Initiative

This paper presents a fully automated method for segmenting articular knee cartilage and bone from in vivo 3-D dual echo steady state images. The magnetic resonance imaging (MRI) datasets were obtained from the Osteoarthritis Initiative (OAI) pilot study and include longitudinal images from controls and subjects with knee osteoarthritis (OA) scanned twice at each visit (baseline, 24 month). Initially, human experts segmented six MRI series. Five of the six resultant sets served as reference atlases for a multiatlas segmentation algorithm. The methodology created precise knee segmentations that were used to extract articular cartilage volume, surface area, and thickness as well as subchondral bone plate curvature. Comparison to manual segmentation showed Dice similarity coefficient (DSC) of 0.88 and 0.84 for the femoral and tibial cartilage. In OA subjects, thickness measurements showed test-retest precision ranging from 0.014 mm (0.6%) at the femur to 0.038 mm (1.6%) at the femoral trochlea. In the same population, the curvature test-retest precision ranged from 0.0005 mm(-1) (3.6%) at the femur to 0.0026 mm(-1) (11.7%) at the medial tibia. Thickness longitudinal changes showed OA Pearson correlation coefficient of 0.94 for the femur. In conclusion, the fully automated segmentation methodology produces reproducible cartilage volume, thickness, and shape measurements valuable for the study of OA progression.

Quantification of stiffness change in degenerated articular cartilage using optical coherence tomography-based air-jet indentation

Articular cartilage is a thin complex tissue that covers the bony ends of joints. Changes in the composition and structure of articular cartilage will cause degeneration, which may further lead to osteoarthritis. Decreased stiffness is one of the earliest symptoms of cartilage degeneration and also represents the imperfect quality of repaired cartilage. An optical coherence tomography (OCT)-based air-jet indentation system was recently developed in our group to measure the mechanical properties of soft tissues. In this study, this system was applied to quantify the change of mechanical properties of articular cartilage after degeneration induced by enzymatic digestions. Forty osteochondral disks (n = 20 × 2) were prepared from bovine patellae and treated with collagenase and trypsin digestions, respectively. The apparent stiffness of the cartilage was measured by the OCT-based air-jet indentation system before and after the degeneration. The results were also compared with those from a rigid contact mechanical indentation and an ultrasound water-jet indentation. Through the air-jet indentation, it was found that the articular cartilage stiffness dropped significantly by 84% (p < 0.001) and 63% (p < 0.001) on average after collagenase and trypsin digestions, respectively. The stiffness measured by the air-jet indentation system was highly correlated (R > 0.8, p < 0.001) with that from the other two indentation methods. This study demonstrated that the OCT-based air-jet indentation can be a useful tool to quantitatively assess the mechanical properties of articular cartilage, and this encourages us to further develop a miniaturized probe suitable for arthroscopic applications.

MRI-based extended ordered values more efficiently differentiate cartilage loss in knees with and without joint space narrowing than region-specific approaches using MRI or radiography--data from the OA initiative

OBJECTIVE

The sensitivity to change of quantitative analysis of cartilage in knee osteoarthritis using magnetic resonance imaging (MRI) is compromised by the spatial heterogeneity of cartilage loss. We explore whether extended (medial-lateral) "ordered values" (OVs) are superior to conventional approaches of analyzing subregional cartilage thickness loss and to radiography, in differentiating rates of progression in knees with and without joint space narrowing (JSN).

METHODS

607 Osteoarthritis Initiative (OAI) participants (308 without and 299 with baseline JSN at baseline) were studied over 12 months. Subregional femorotibial cartilage loss was determined in all knees, and changes in minimum joint space width (mJSW) in a subset of 290 knees. Subregional thickness changes in medial and lateral tibial and femoral cartilages were sorted in ascending order (OV1-16). A Wilcoxon rank-sum test was used to compare rates of change in knees with and without JSN.

RESULTS

JSN-knees displayed greater cartilage loss than those without JSN, with minimal P-values of 0.008 for femorotibial subregions, 3.3×10(-4) for medial OV1, and 5.4×10(-7) for extended (medial and lateral) OV1. mJSW measurements (n=290) did not discriminate between longitudinal rates of change in JSN vs no-JSN knees (P=0.386), whereas medial OV1 (P=5.1×10(-4)) and extended OV1 did (P=2.1×10(-5)).

CONCLUSION

Extended OVs showed higher sensitivity to detecting differences in longitudinal rates of cartilage loss in knees with and without baseline JSN than anatomical (sub)regions and radiography. The OV technique also circumvents challenges of selecting particular regions "a priori" in clinical trials and may thus provide a powerful tool in studying risk factors or treatment efficacy in osteoarthritis.

Imaging of synovitis in osteoarthritis: current status and outlook

OBJECTIVES

This review article provides an overview of the current state of imaging of synovitis in osteoarthritis (OA), looking at recent advances and controversies and focusing particularly on the application of ultrasound and magnetic resonance imaging (MRI) in the assessment of the hand and knee joint. Computed tomography and nuclear medicine including positron emission tomography are also briefly discussed.

METHODS

PubMed and MEDLINE search for articles published up to 2010, using the keywords synovitis, osteoarthritis, rheumatoid arthritis, pathogenesis, imaging, radiography, computed tomography, nuclear medicine, magnetic resonance imaging, ultrasound, and pain.

RESULTS

Synovitis is defined as inflammation of the synovial membrane. Modern imaging techniques have demonstrated that synovial pathology is common in the early and late stages of OA and may be associated with pain. The current standard for OA imaging in clinical practice is conventional radiography but it does not allow direct visualization of synovitis. MRI without contrast administration, although widely used in clinical studies, cannot assess synovitis directly. Contrast-enhanced MRI and ultrasound, however, both allow direct visualization of synovitis including early inflammatory changes. They are regularly used to image synovitis in rheumatoid arthritis and increasingly in OA.

CONCLUSIONS

Synovitis is increasingly recognized as an important feature of the pathophysiology of OA, although there is conflicting evidence with respect to its association with disease severity and clinical parameters. Contrast-enhanced MRI and ultrasound are the most important methods for assessing synovitis associated with OA.

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

OBJECTIVES

The objectives were to evaluate improvement in reliability of joint space width (JSW) measurements, according to the previous experience of the readers in hip osteoarthritis (OA).

METHODS

Fifty radiographs in hip OA patients from a randomized controlled trial (ECHODIAH) were read 12 times by two readers with different levels of experience in radiographic interpretation. Intra-reader reliability and inter-reader reliability were assessed through calculation of the smallest detectable difference (SDD) and the intra-class correlation coefficient (ICC).

RESULTS

Intra-reader reliability: for the experienced reader, no significant change in SDD was observed with repeated JSW measurements. For the junior reader, the SDD decreased significantly from 0.90 mm to 0.65 mm (P=0.002). A plateau of SDD was reached after reading 200 to 300 radiographs, with a value close to the mean SDD of the experienced reader (0.67 mm). ICCs were high (>0.88) for both the senior and the junior readers. Inter-reader reliability: no improvement in inter-reader reliability was noted with repeated measurements of JSW (SDD=0.81 mm). However, no additional training sessions were performed. ICCs were high (>0.85).

CONCLUSION

This study indicated for the first time a learning curve in analyzing JSW in hip OA for an inexperienced reader. After analyzing 200 to 300 radiographs, the junior reader reached an intra-reader reliability similar to the experienced reader. Moreover, the information brought by the ICC was not sufficient, suggesting that the SDD should be systematically reported in studies evaluating OA radiographic progression, on top of the ICC, to help in interpreting the JSW reliability.

Optical imaging: new tools for arthritis

Conventional radiography, ultrasound, CT, MRI, and nuclear imaging are the current imaging modalities used for clinical evaluation of arthritis which is highly prevalent and a leading cause of disability. Some of these types of imaging are also used for monitoring disease progression and treatment response of arthritis. However, their disadvantages limit their utilities, such as ionizing radiation for radiography, CT, and nuclear imaging; suboptimal tissue contrast resolution for radiography, CT, ultrasound, and nuclear imaging; high cost for CT and MRI and nuclear imaging; and long data-acquisition time with ensuing patient discomfort for MRI. Recently, there have been considerable advances in nonionizing noninvasive optical imaging which has demonstrated promise for early diagnosis, monitoring therapeutic interventions and disease progression of arthritis. Optical based molecular imaging modalities such as fluorescence imaging have shown high sensitivity in detection of optical contrast agents and can aid early diagnosis and ongoing evaluation of chronic inflammatory arthritis. Optical transillumination imaging or diffuse optical tomography may differentiate normal joint clear synovial fluid from turbid and pink medium early in the inflammatory process. Fourier transform infrared spectroscopy has been used to evaluate fluid composition from joints affected by arthritis. Hemodynamic changes such as angiogenesis, hypervascularization, and hypoxia in arthritic articular tissue can potentially be observed by diffuse optical tomography and photoacoustic tomography. Optical measurements could also facilitate quantification of hemodynamic properties such as blood volume and oxygenation levels at early stages of inflammatory arthritis. Optical imaging provides methodologies which should contribute to detection of early changes and monitoring of progression in pathological characteristics of arthritis, with relatively simple instrumentation.