Associations Between Knee Effusion-synovitis and Joint Structural Changes in Patients with Knee Osteoarthritis

Intra-Articular Injection of Interleukin-8 Neutralizing Monoclonal Antibody Effectively Attenuates Osteoarthritis Progression in Rabbits

OBJECTIVE

Cytokines are implicated in the pathogenesis of osteoarthritis (OA), and this study aims to assess the therapeutic potential of an IL-8 neutralizing monoclonal antibody (mAb) for OA intervention.

DESIGN

The study employed a rabbit model of OA induced by anterior cruciate ligament transection (ACLT) surgery to investigate the effects of an interleukin (IL)-8 neutralizing mAb, with hyaluronic acid (HA) used as a positive control. Primary outcomes assessed in the rabbits included cartilage repair, synovitis, joint effusion, changes in footprints, and lower limb loading conditions.

RESULTS

Compared to HA, intra-articular injection of the IL-8 neutralizing mAb demonstrated a more pronounced attenuation of OA progression and enhancement of cartilage repair. We observed a reduction in synovitis and joint effusion, indications of bone marrow edema, as well as improvements in lower limb function. In knees treated with the neutralizing IL-8 mAb, there was a significant decrease in IL-8 levels within the synovial tissues.

CONCLUSIONS

The IL-8 neutralizing mAb exhibits promising therapeutic potential in the management of OA by attenuating inflammation and facilitating cartilage repair. However, further investigations are warranted to comprehensively elucidate the underlying mechanisms, optimize treatment protocols, and ensure the long-term safety and efficacy of this innovative therapeutic approach.

Comprehensive Grading System of Inflammatory Features of the Lumbar Facet Joints on Magnetic Resonance Imaging

STUDY DESIGN

Retrospective.

OBJECTIVE

We aimed to describe a magnetic resonance imaging (MRI)-based grading system of inflammatory features of the lumbar facet joints using an atlas and assess its reliability.

SUMMARY OF BACKGROUND DATA

Chronic low back pain is often caused by facet joint arthropathy. Inflammatory features are often evident on MRI. While several grading systems of facet arthropathy have been described, there is scant data on the reliability of these systems, and none focus exclusively on inflammatory features.

MATERIALS AND METHODS

We describe a grading system that assesses facet joint effusion, bone marrow edema, and soft tissue edema. Each feature was graded from 0 to 3 (facet edema) or 0 to 2 (bone marrow edema intensity and extent, soft tissue edema intensity and extent). Four spine experts graded MRIs of 50 subjects at the bilateral L3/4, L4/5, and L5/S1 levels. All subjects had symptomatic facet arthropathy and received therapeutic facet joint injections. We assessed the intra-reader and inter-reader reliability of each feature at each joint and summarized across all six joints.

RESULTS

The mean age of subjects was 56 years (SD = 17), and 48% were female. The injections occurred at the L3/4 level in 12% of cases, at L4/5 in 88%, and at L5/S1 in 80% of cases. The intra-reader reliability kappa's for each feature ranged from 0.42 to 0.81. In contrast, the inter-reader reliability kappa values for each feature ranged from 0.37 to 0.54.

CONCLUSION

MRI inflammatory features of the lumbar facet joints are often noted in patients with low back pain. The proposed grading system is reliable and could serve as a research tool for studies assessing the clinical relevance and prognostic value of these features.

Clinical Efficacy of 2-Needle Joint Lavage for Osteoarthritis-Related Knee Pain and Predictors of Response Based on Knee MRI Osteoarthritis Knee Score: A Medical Records Review Study

BACKGROUND

Knee osteoarthritis (OA) is notoriously difficult to treat. Pain is the key symptom for patients to seek medical attention. This study aimed to evaluate the therapeutic efficacy of joint lavage (JL) for OA-related knee pain and to explore the knee pathological changes detected by magnetic resonance imaging that may affect the prognosis of patients who received JL.

METHODS

Eighty-two hospitalized patients who were diagnosed with knee OA and received JL in our department were finally enrolled in this study. The patients' clinical data including Numeric Rating Scale (NRS), Western Ontario and McMaster Osteoarthritis Index pain subscale, analgesic medication usage, adverse events, and magnetic resonance imaging data of the affected knee joint scored by the MRI Osteoarthritis Knee Score were recorded and analyzed.

RESULTS

The NRS scores significantly decreased after JL and remained steady until 6 months ( p < 0.001). The Western Ontario and McMaster Osteoarthritis Index pain scores and the percentage of patients who needed analgesic medication significantly decreased at 6 months compared with baseline ( p < 0.001). At 6 months after JL, 51 of the 82 patients experienced ≥50% improvement in their NRS scores (effective). Multivariate binary logistic regression analysis revealed that duration of pain (odds ratio [OR], 1.022; 95% confidence interval [CI], 1.003-1.042; p = 0.024), bone marrow lesion score (OR, 1.221; 95% CI, 1.028-1.450; p = 0.023), and cartilage loss score (OR, 1.272; 95% CI, 1.021-1.585; p = 0.032) significantly influenced the therapeutic efficacy of JL.

CONCLUSIONS

JL treatment can significantly alleviate the OA-related knee pain in at least 6 months. JL tends to provide limited benefit for patients with long duration of pain, serious bone marrow lesions, and severe cartilage loss.

Bone marrow lesions in osteoarthritis: From basic science to clinical implications

Osteoarthritis (OA) is the most prevalent musculoskeletal disease characterized by multiple joint structure damages, including articular cartilage, subchondral bone and synovium, resulting in disability and economic burden. Bone marrow lesions (BMLs) are common and important magnetic resonance imaging (MRI) features in OA patients. Basic and clinical research on subchondral BMLs in the pathogenesis of OA has been a hotspot. New evidence shows that subchondral bone degeneration, including BML and angiogenesis, occurs not only at or after cartilage degeneration, but even earlier than cartilage degeneration. Although BMLs are recognized as important biomarkers for OA, their exact roles in the pathogenesis of OA are still unclear, and disputes about the clinical impact and treatment of BMLs remain. This review summarizes the current basic and clinical research progress of BMLs. We particularly focus on molecular pathways, cellular abnormalities and microenvironmental changes of subchondral bone that contributed to the formation of BMLs, and emphasize the crosstalk between subchondral bone and cartilage in OA development. Finally, potential therapeutic strategies targeting BMLs in OA are discussed, which provides novel strategies for OA treatment.

Impact of Sustained Synovitis on Knee Joint Structural Degeneration: 4-Year MRI Data from the Osteoarthritis Initiative

BACKGROUND

Synovial inflammation is a risk factor for osteoarthritis (OA). But to date, there is limited information on how inflammation impacts progression of knee OA.

PURPOSE

To investigate how sustained synovitis, assessed with semi-quantitative magnetic resonance imaging (MRI) scores, impacts progression of knee degenerative changes over 4 years.

STUDY TYPE

Retrospective cohort study.

SUBJECTS

In 249 participants (N = 132 women [53%]), from the Osteoarthritis Initiative (OAI) two definitions for synovitis were used resulting in two groups of participants with sustained synovitis at baseline, 2-year, and 4-year follow-up (N = 80 and N = 132), and two groups without synovitis at all three time points (N = 81 and N = 47).

FIELD STRENGTH/SEQUENCE

3 T intermediate-weighted (IW) turbo spin-echo (TSE) sequence and three-dimensional (3D) dual-echo steady-state (DESS) sequence.

ASSESSMENT

Synovitis was scored semi-quantitatively using the Anterior Cruciate Ligament Osteoarthritis Score (ACLOAS), MRI Osteoarthritis Knee Score (MOAKS), and synovial proliferation score (SPS). Two MRI-based definitions of synovitis were used: (i) score ≥2 based on cumulative score of MOAKS and ACLOAS, and (ii) score ≥3 based on the cumulative score of ACLOAS, MOAKS, and SPS. Changes in structural abnormalities from baseline to year 4 measured using the whole-organ MRI score (WORMS) were defined as outcomes.

STATISTICAL TESTS

Linear regression models were used to compare the differences in longitudinal changes in WORMS scores between participants with and without sustained synovitis for each definition of sustained synovitis. A P-value of <0.05 was considered statistically significant.

RESULTS

Significantly higher rates of progression were found in participants with synovitis for patellar (Beta coeff. = 0.29) and medial tibial cartilage abnormalities (Beta coeff. = 0.29) for definition (i). For definition (ii), patellar (Beta coeff. = 0.36) and medial femoral cartilage (Beta coeff. = 0.30) abnormalities demonstrated significant differences.

DATA CONCLUSION

Greater progression of structural degenerative disease was observed in individuals with sustained synovitis compared to those without sustained synovitis, suggesting that sustained synovitis is associated with progressive OA.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

Associations of Dietary Macroelements with Knee Joint Structures, Symptoms, Quality of Life, and Comorbid Conditions in People with Symptomatic Knee Osteoarthritis

Background: Osteoarthritis (OA), the most common joint disease in the elderly, has no cure. Macroelements are vital in human health and their relationships with OA are not clear. Clarifying the relationships between macroelements and OA may assist knee OA management. Methods: This study was a post-hoc analysis using data from a two-year randomized controlled trial among 392 participants with knee OA. Dietary macroelements, including calcium, magnesium, potassium, and phosphorus were computed-based on a semi-quantitative food frequency questionnaire at baseline. Knee joint structures (including cartilage volume, cartilage defect, bone marrow lesions, and effusion-synovitis volume), OA symptoms, quality of life, and OA comorbid conditions (including lower limb muscle strength and depressive symptoms) were assessed at baseline and month 24. Western Ontario and McMaster Universities (WOMAC) Index and depressive symptoms were assessed at baseline and months 3, 6, 12, and 24. Quality of life and lower limb muscle strength were assessed at baseline and months 6, 12, and 24. All analyses were conducted using mixed-effects models. Results: Higher dietary magnesium and potassium were associated with fewer OA symptoms, higher quality of life, greater lower limb muscle strength, and fewer depressive symptoms, but not with knee joint structures. Higher dietary calcium and phosphorus was not associated with any of the OA-related outcomes, except that dietary phosphorus was associated with greater lower limb muscle strength. Conclusions: In the longitudinal analyses, higher dietary magnesium and potassium intake are associated with fewer OA symptoms, higher quality of life, and milder comorbid conditions in patients with knee OA, suggesting dietary magnesium and potassium may have beneficial effects on OA and could be used for knee OA management.

Association between knee inflammation and knee pain in patients with knee osteoarthritis: a systematic review

OBJECTIVE

To systematically review the literature on the relationship between markers of inflammation and pain in patients with knee osteoarthritis (OA).

METHODS

We searched MEDLINE, Web of Science and EMBASE databases from inception until June 2021. Eligible articles had to report on the association between inflammation (as measured by effusion, synovitis, baker's cysts, cytokines and C-reactive protein) and pain in patients with radiographic knee OA. Two reviewers independently performed a screening on title and abstracts, data extraction and risk of bias assessment using the Newcastle-Ottawa Scale (NOS). A best evidence synthesis was conducted for each inflammatory sign included in this review.

RESULTS

37 studies were included. Articles reported on the following measures: effusion or synovitis assessed via ultrasound (n = 9) or magnetic resonance imaging (MRI) (n = 17); baker's cyst (n = 3); cytokine concentrations (n = 11); and C-reactive protein levels (n = 4). The strength of the association between inflammation and pain does not exceed the moderate level (i.e., correlation coefficient values ranging from 0.19 to 0.61). Moderate levels of evidence were found for the association between synovitis (measured with ultrasound or contrast enhanced MRI) and pain. The levels of evidence between effusion (assessed via ultrasound), effusion/synovitis (assessed via non-contrast enhanced MRI), Baker's cyst, cytokines, C-reactive protein and pain were conflicting.

CONCLUSIONS

Different inflammatory markers are associated with pain but the correlation ranges from weak to moderate, and the quality of evidence from conflicting to moderate. Further research is needed to strengthen the level of evidence and to establish mechanisms.

A prospective cohort study on cam morphology and its role in progression of osteoarthritis

Background

Cam morphology contributes to the development of hip osteoarthritis (OA) but is less studied in the general population. This study describes its associations with clinical and imaging features of hip OA.

Methods

Anteroposterior hip radiographs of 1019 participants from the Tasmanian Older Adult Cohort (TASOAC) were scored at baseline for α angle (cam morphology) in both hips. Using the Altman's atlas, radiographic hip OA (ROA) was assessed at baseline. Hip pain and right hip structural changes were assessed on a subset of 245 magnetic resonance images (MRI) at 5 years. Joint registry data for total hip replacement (THR) was acquired 14 years from baseline.

Results

Of 1906 images, cam morphology was assessed in 1016 right and 890 left hips. Cross‐sectionally, cam morphology modestly associated with age (prevalence ratio [PR]: 1.02 P = .03) and body mass index (BMI) (PR: 1.03‐1.07, P = .03) and strongly related to male gender (PR: 2.96, P < .001). Radiographically, cam morphology was prevalent in those with decreased joint space (PR: 1.30 P = .03) and osteophytes (PR: 1.47, P = .03). Longitudinally, participants with right cam and high BMI had more hip pain (PR: 17.9, P = .02). At the end of 5 years of follow‐up these participants were also more likely to have structural changes such as bone marrow lesions (BMLs) (PR: 1.90 P = .04), cartilage defects (PR: 1.26, P = .04) and effusion‐synovitis at multiple sites (PR: 1.25 P = .02). Cam morphology at baseline in either hip predicted up to threefold risk of THR (PR: 3.19, P = .003) at the end of 14 years.

Conclusion

At baseline, cam morphology was linked with age, higher weight, male gender, early signs of radiographic OA such as joint space narrowing (JSN) and osteophytes (OST). At follow‐up, cam predicted development of hip BMLs, hip effusion‐synovitis, cartilage damage and THR. These findings suggest that cam morphology plays a significant role in early OA and can be a precursor or contribute to hip OA in later life.

Effects of isometric contraction of the quadriceps on the hardness and blood flow in the infrapatellar fat pad

[Purpose] This study aimed to clarify the influence of the isometric contraction of the quadriceps (ICQ) with low intensity on the circulation in the infrapatellar fat pad (IFP). [Participants and Methods] The participants were 7 males and 5 females, with an average age of 21.5 ± 1.4 years. IFP hardness was measured using shear wave ultrasound elastography and Biodex. Tissue oxygenation was measured via near-infrared spectroscopy using oxygenated hemoglobin (O2Hb), deoxygenated hemoglobin (HHb), and total hemoglobin (cHb) as indices. The mean values were calculated for three periods: 1 min of rest immediately before the exercise task (before ICQ), the lower limit of the 10 sets during the exercise task (during ICQ), and 3–4 min after the exercise task (after ICQ). IFP hardness was compared between resting conditions and ICQ, and tissue oxygenation was compared before, during, and after ICQ. [Results] ICQ significantly increased IFP hardness. Tissue hemoglobin, O2Hb, and cHb decreased significantly during ICQ and increased after ICQ compared to that before ICQ. HHb decreased during ICQ and recovered significantly after ICQ. [Conclusion] In healthy participants, low-intensity ICQ increases the hardness and oxygenation of the IFP. This study may partly explain the unknown pain relief mechanism of exercise therapy.

Engineered nasal cartilage for the repair of osteoarthritic knee cartilage defects

[Figure: see text].

The interactions between MRI-detected osteophytes and bone marrow lesions or effusion-synovitis on knee symptom progression: an exploratory study

OBJECTIVES

To investigate the longitudinal association between MRI-detected osteophyte scores and progression of knee symptoms, and whether the association was modified in the presence of bone marrow lesions (BMLs) or effusion-synovitis.

METHODS

Data from Vitamin D Effects on Osteoarthritis (VIDEO) study, a randomized, double-blinded and placebo-controlled clinical trial in symptomatic knee osteoarthritis (OA) patients, were analyzed as an exploratory study. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was used to assess knee symptoms. Osteophytes, BMLs and effusion-synovitis were measured using MRI.

RESULTS

334 participants with MRI information and WOMAC score (baseline and follow-up) were included in the analyses, with 24.3% of them having knee pain increased 2 years later. Statistically significant interactions were found between MRI-detected osteophytes and BMLs or effusion-synovitis on increased knee symptoms. In participants with BMLs, higher baseline scores of MRI-detected osteophytes in most compartments were significantly associated with increased total knee pain, weight-bearing pain, stiffness, and physical dysfunction, after adjustment for age, sex, body mass index, intervention and effusion-synovitis. In participants with effusion-synovitis, higher baseline scores of MRI-detected osteophytes in almost all the compartments were significantly associated with increased total knee pain, weight-bearing pain, stiffness, and physical dysfunction, after adjustment for age, sex, body mass index, intervention and BMLs. In contrast, MRI-detected osteophyte scores were generally not associated with knee symptom progression in participants without baseline BMLs or effusion-synovitis.

CONCLUSIONS

MRI-detected OPs are associated with increased total knee pain, weight-bearing knee pain, stiffness and physical dysfunction in participants presenting BMLs or effusion-synovitis, but not in participants lacking BMLs or effusion-synovitis. This suggests they could interact with bone or synovial abnormalities to induce symptoms in knee OA.

Relationship between motion, using the GaitSmartTM system, and radiographic knee osteoarthritis: an explorative analysis in the IMI-APPROACH cohort

Objectives

To assess underlying domains measured by GaitSmart^TMparameters and whether these are additional to established OA markers including patient reported outcome measures (PROMs) and radiographic parameters, and to evaluate if GaitSmart analysis is related to the presence and severity of radiographic knee OA.

Methods

GaitSmart analysis was performed during baseline visits of participants of the APPROACH cohort (n = 297). Principal component analyses (PCA) were performed to explore structure in relationships between GaitSmart parameters alone and in addition to radiographic parameters and PROMs. Logistic and linear regression analyses were performed to analyse the relationship of GaitSmart with the presence (Kellgren and Lawrence grade ≥2 in at least one knee) and severity of radiographic OA (ROA).

Results

Two hundred and eighty-four successful GaitSmart analyses were performed. The PCA identified five underlying GaitSmart domains. Radiographic parameters and PROMs formed additional domains indicating that GaitSmart largely measures separate concepts. Several GaitSmart domains were related to the presence of ROA as well as the severity of joint damage in addition to demographics and PROMs with an area under the receiver operating characteristic curve of 0.724 and explained variances (adjusted R²) of 0.107, 0.132 and 0.147 for minimum joint space width, osteophyte area and mean subchondral bone density, respectively.

Conclusions

GaitSmart analysis provides additional information over established OA outcomes. GaitSmart parameters are also associated with the presence of ROA and extent of radiographic severity over demographics and PROMS. These results indicate that Gaitsmart^TM may be an additional outcome measure for the evaluation of OA.

Association Between Clinical Symptoms and Radiographic Features in Late-Stage Knee Osteoarthritis Using a New Radiographic Parameter

OBJECTIVE

In this study, we proposed a new radiographic parameter, the plateau attrition index (PAI), and the PAI grades (PAIs) to explore the relationship between subchondral attrition of the tibial plateau and symptoms of knee osteoarthritis (OA) in patients with late-stage knee osteoarthritis.

METHOD

One hundred nineteen patients with late-stage knee osteoarthritis were enrolled. The Kellgren and Lawrence (K/L) grades and hip-knee-ankle (HKA) angle were used to characterize the radiographic features of knee OA. The bone attrition of the tibial plateau was determined by the PAI and PAIs. The symptoms of knee OA were assessed by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), which is composed of the WOMAC pain (WOMP), WOMAC stiffness (WOMS), and WOMAC function (WOMF) subscores. WOMAC pain scores were divided into non-weight-bearing pain (NWBP) and weight-bearing pain (WBP) subcategories. The Pearson correlation coefficient was used to determine the relationship between the PAI, HKA angle, and WOMAC scores. The Spearman rank correlation coefficient was used to evaluate the correlation between the WOMAC score and the PAIs and K/L grades.

RESULTS

The distribution of the WOMAC scores according to the PAIs was significant (P < .01). A positive correlation was identified between the PAI and the WOMAC, WOMP, WOMF and WBP scores (r = 0.29, 0.34, 0.26 and 0.34, P < .01, respectively). In addition, the PAIs was also significantly correlated with the WOMAC, WOMP, WOMF, and WBP scores (r = 0.37, 0.38, 0.35 and 0.44, P < .01, respectively).

CONCLUSIONS

The attrition of tibial subchondral bone determined by the new parameter, the plateau attrition index, was correlated with symptoms, especially weight-bearing pain in late-stage knee OA.

Preoperative Grades of Osteoarthritis and Meniscus Volume Correlate with Clinical Outcomes of Osteochondral Graft Treatment for Cartilage Defects in the Knee

OBJECTIVE

To identify preoperative imaging-based indicators of knee degeneration that correlate with graft failure risk and postoperative clinical outcome scores after osteochondral graft treatment for chondral defects of the knee.

DESIGN

Prospectively collected data from 113 patients (mean age, 34 years; 65% male) treated with mosaicplasty or osteochondral allograft transplantation (OCA) was reviewed. Four different aspects of knee degeneration were examined based on preoperative radiographs or magnetic resonance imaging: (1) Osteoarthritis using the Kellgren-Lawrence (KL) grading system, (2) meniscus volume, (3) meniscus quality, and (4) synovitis. Primary outcomes included graft failure, defined by removal/revision of the graft or conversion to arthroplasty, and patient responses to clinical outcome scores.

RESULTS

Forty-one knees (36%) underwent mosaicplasty, and 72 knees (64%) underwent OCA. Mean duration of follow-up was 4.5 years (range, 2-14 years). A preoperative KL grade of ≥3 was correlated with increased failure rates (P = 0.01), lower postoperative International Knee Documentation Committee form (IKDC), Activities of Daily Living of the Knee Outcome Survey (KOS-ADL), and Overall Condition scores (P < 0.01), and decreased improvement in Overall Condition scores (P = 0.01). Within an individual tibiofemoral compartment, a preoperative meniscus volume grade of ≥3 (indicating <50% meniscus volume remaining) was correlated with increased condylar graft failure rates (P < 0.01). Preoperative meniscus quality and synovitis grades were not associated with graft failure rates or clinically meaningful differences in postoperative outcome scores.

CONCLUSIONS

Greater preoperative osteoarthritis and meniscus volume loss were correlated with increased graft failure rates after osteochondral graft treatment for chondral defects of the knee.

Association of serum levels of inflammatory markers and adipokines with joint symptoms and structures in participants with knee osteoarthritis

OBJECTIVE

To investigate the longitudinal associations of serum inflammatory markers and adipokines with joint symptoms and structures in participants with knee osteoarthritis (OA).

METHODS

Two hundred participants (46.5% female, mean age 63.1 years, mean BMI 29.5 kg/m2) from Tasmania part of the VIDEO (Vitamin D Effect on OA) study were randomly selected in the current study. Serum levels of 19 biomarkers, scores of Western Ontario and McMaster Universities Index (WOMAC), and magnetic resonance imaging-assessed knee structures were evaluated at baseline and month 24. The patterns of biomarkers were derived from principal component analysis and their association with knee symptoms and structures were examined using adjusted generalized estimating equations.

RESULTS

Five components explained 78% of the total variance. Interleukin (IL)-1β, -2, -4, -6, -8, -17A, -17F, -21, -22 and -23 loaded the highest on the first component, which was associated with increased bone marrow lesions (BMLs) and WOMAC dysfunction score. IL-10, -12 and granulocyte-macrophage colony-stimulating factor loaded on the second component, which was associated with increased cartilage volume, and decreased effusion-synovitis and WOMAC scores. Leptin, adipsin and C-reactive protein loaded on the third component, which was positively associated with WOMAC scores. Resistin loaded on the fourth component, which was associated with increased BMLs and cartilage defects. Apelin-36 and adiponectin loaded on the fifth component, which was associated with increased BMLs.

CONCLUSION

Various inflammatory and metabolic components were associated differently with joint symptoms and structural changes in knee OA, suggesting a complex inflammatory and metabolic inter-relationship in the pathogenesis of knee OA.

Associations between diet quality and knee joint structures, symptoms and systemic abnormalities in people with symptomatic knee osteoarthritis

BACKGROUND & AIMS

The evidence of benefiting from a high-quality diet for knee osteoarthritis (OA) joint structures, symptoms, and systemic abnormalities is limited. Clarifying the relationship between diet quality and knee OA could provide useful information for knee OA management. To investigate the associations between diet quality and knee joint structures, symptoms, lower limb muscle strength, depressive symptoms, and quality of life in people with knee OA.

METHODS

This study was a post-hoc, exploratory analysis using data from a randomized controlled trial in symptomatic knee OA participants with a follow-up time of 24 months. In brief, eligible participants of the original study were aged 50-79 years, had symptomatic knee OA, and had a pain of 20-80 mm on a 100-mm visual analog scale. After excluding the patients without information on diet quality, 392 participants were included in this post-hoc analysis. Diet quality was assessed at baseline using the Australian Recommended Food Score (ARFS) which includes subscores of vegetable, fruit, grain, dairy products, fat, and alcohol. Knee joint structures (including cartilage volume, cartilage defect, bone marrow lesions, and effusion-synovitis volume assessed by magnetic resonance imaging), OA symptoms, lower limb muscle strength, depressive symptoms, and quality of life were assessed at baseline and follow up. Mixed-effects models were used to assess the associations of diet quality with those outcomes.

RESULTS

Diet quality mainly reflect diet variety within the core food was not associated with knee structures and OA symptoms, but was associated with greater lower limb muscle strength (β = 0.66, P = 0.001), lower depressive symptom (β = -0.08, P = 0.001), and better quality of life (β = -0.06, P = 0.002). In further analyses of food group-based sub-scores, only the vegetable sub-score had the similar associations with lower limb muscle strength (β = 1.03, P = 0.004), depressive symptom (β = -0.17, P < 0.001), and quality of life (β = -0.14, P < 0.001).

CONCLUSIONS

Higher diet quality, mainly vegetable diet quality, is associated with greater lower limb muscle strength, less depressive symptoms, and higher quality of life in knee OA patients, suggesting higher diet quality may have protective effects on knee OA.

Association between Baseline Osteoarthritic Features on MR Imaging and Clinical Outcome after Genicular Artery Embolization for Knee Osteoarthritis

PURPOSE

To explore the association between baseline osteoarthritis (OA)-related magnetic resonance (MR) imaging features and pain reduction after genicular artery embolization (GAE) in patients with mild-to-moderate symptomatic knee OA resistant to conservative therapy.

MATERIALS AND METHODS

This was a retrospective analysis of patients with mild-to-moderate symptomatic knee OA treated with GAE using imipenem-cilastatin sodium. The clinical outcome was scored at baseline and 6 months after treatment using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). MR images were scored using the MR imaging osteoarthritis knee score. Linear regression was used to evaluate associations of before-treatment MR imaging scores with WOMAC_pain and WOMAC_total reduction after 6 months.

RESULTS

Fifty-four patients (22.2% male; median age, 69.4 years; median WOMAC_pain at baseline, 12) were evaluated. Of all OA features scored, a higher cartilage full-thickness defect score showed the strongest association with less reduction of both WOMAC_pain (B,-0.63 [95% confidence interval (CI), -0.91 to -0.34]; P < .001) and WOMAC_total scores (B, -1.77 [95% CI, -2.87 to -0.67]; P < .001) following treatment. The presence of grade 2-3 effusion synovitis (B, -2.99 [95% CI, -5.39 to -0.60]) bone marrow lesions (B, -0.52 [95% CI, -0.86 to -0.19]), osteophytes (B, -0.21 [95% CI, -0.36 to -0.06]), and cartilage defect surface area score (B, -0.25 [95% CI -0.42 to -0.08]) all showed a significant association with less WOMAC_pain reduction (all P < .05).

CONCLUSIONS

In patients with mild-to-moderate symptomatic knee OA treated with GAE, the presence and severity of full-thickness cartilage defects, effusion synovitis, bone marrow lesions, osteophytes, and cartilage surface area scores at baseline are associated with less favorable clinical outcomes at 6 months.

The bulge sign - a simple physical examination for identifying progressive knee osteoarthritis: data from the Osteoarthritis Initiative

OBJECTIVE

To examine whether the presence of bulge sign or patellar tap was associated with frequent knee pain, progression of radiographic OA (ROA) and total knee replacement (TKR).

METHODS

This study included 4344 Osteoarthritis Initiative participants examined at baseline for bulge sign and/or patellar tap. The clinical signs were categorized as no (none at baseline and 2 years), resolved (present at baseline only), developed (present at 2 years only) and persistent (present at both time points). Frequent knee pain and progression of ROA over 4 years and TKR over 6 years were assessed. Binary logistic regression was used to examine the associations.

RESULTS

A total of 12.7% of participants had bulge sign only, 2.0% had patellar tap only and 3.3% had both. A positive baseline bulge sign was associated with an increased risk of frequent knee pain [OR 1.31 (95% CI 1.04, 1.64), P = 0.02] and TKR [OR 1.47 (95% CI 1.06, 2.05), P = 0.02]. Developed bulge sign was associated with an increased risk of frequent knee pain [OR 1.75 (95% CI 1.34, 2.29), P < 0.001] and progressive ROA [OR 1.67 (95% CI 1.11, 2.51), P = 0.01]. Persistent bulge sign was associated with an increased risk of frequent knee pain [OR 1.60 (95% CI 1.09, 2.35), P = 0.02], progressive ROA [OR 1.84 (95% CI 1.01, 3.33), P = 0.045] and TKR [OR 2.13 (95% CI 1.23, 3.68), P = 0.007]. Patellar tap was not examined for its association with joint outcomes due to its low prevalence.

CONCLUSION

The presence of bulge sign identifies individuals at increased risk of frequent knee pain, progression of ROA and TKR. This provides clinicians with a quick, simple, inexpensive method for identifying those at higher risk of progressive knee OA who should be targeted for therapy.

Risk factors and the natural history of accelerated knee osteoarthritis: a narrative review

BACKGROUND

Osteoarthritis is generally a slowly progressive disorder. However, at least 1 in 7 people with incident knee osteoarthritis develop an abrupt progression to advanced-stage radiographic disease, many within 12 months. We summarize what is known - primarily based on findings from the Osteoarthritis Initiative - about the risk factors and natural history of accelerated knee osteoarthritis (AKOA) - defined as a transition from no radiographic knee osteoarthritis to advanced-stage disease < 4 years - and put these findings in context with typical osteoarthritis (slowly progressing disease), aging, prior case reports/series, and relevant animal models. Risk factors in the 2 to 4 years before radiographic manifestation of AKOA (onset) include older age, higher body mass index, altered joint alignment, contralateral osteoarthritis, greater pre-radiographic disease burden (structural, symptoms, and function), or low fasting glucose. One to 2 years before AKOA onset people often exhibit rapid articular cartilage loss, larger bone marrow lesions and effusion-synovitis, more meniscal pathology, slower chair-stand or walking pace, and increased global impact of arthritis than adults with typical knee osteoarthritis. Increased joint symptoms predispose a person to new joint trauma, which for someone who develops AKOA is often characterized by a destabilizing meniscal tear (e.g., radial or root tear). One in 7 people with AKOA onset subsequently receive a knee replacement during a 9-year period. The median time from any increase in radiographic severity to knee replacement is only 2.3 years. Despite some similarities, AKOA is different than other rapidly progressive arthropathies and collapsing these phenomena together or extracting results from one type of osteoarthritis to another should be avoided until further research comparing these types of osteoarthritis is conducted. Animal models that induce meniscal damage in the presence of other risk factors or create an incongruent distribution of loading on joints create an accelerated form of osteoarthritis compared to other models and may offer insights into AKOA.

CONCLUSION

Accelerated knee osteoarthritis is unique from typical knee osteoarthritis. The incidence of AKOA in the Osteoarthritis Initiative and Chingford Study is substantial. AKOA needs to be taken into account and studied in epidemiologic studies and clinical trials.

KARAOKE: Krill oil versus placebo in the treatment of knee osteoarthritis: protocol for a randomised controlled trial

BACKGROUND

Knee osteoarthritis (OA) is a common and important cause of pain and disability, but interventions aimed at modifying structures visible on imaging have been disappointing. While OA affects the whole joint, synovitis and effusion have been recognised as having a role in the pathogenesis of OA. Krill oil reduces knee pain and systemic inflammation and could be used for targeting inflammatory mechanisms of OA.

METHODS/DESIGN

We will recruit 260 patients with clinical knee OA, significant knee pain and effusion-synovitis present on MRI in five Australian cities (Hobart, Melbourne, Sydney, Adelaide and Perth). These patients will be randomly allocated to the two arms of the study, receiving 2 g/day krill oil or inert placebo daily for 6 months. MRI of the study knee will be performed at screening and after 6 months. Knee symptoms, function and MRI structural abnormalities will be assessed using validated methods. Safety data will be recorded. Primary outcomes are absolute change in knee pain (assessed by visual analog score) and change in size of knee effusion-synovitis over 24 weeks. Secondary outcomes include improvement in knee pain over 4, 8, 12, 16 and 20 weeks. The primary analyses will be intention-to-treat analyses of primary and secondary outcomes. Per protocol analyses adjusting for missing data and for treatment compliance will be performed as the secondary analyses.

DISCUSSION

This study will provide high-quality evidence to assess whether krill oil 2 g/day reduces pain and effusion-synovitis size in older adults with clinical knee OA and knee effusion-synovitis. If krill oil is effective and confirmed to be safe, we will provide compelling evidence that krill oil improves pain and function, changes disease trajectory and slows disease progression in OA. Given the lack of approved therapies for slowing disease progression in OA, and moderate cost of krill oil, these findings will be readily translated into clinical practice.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry, ACTRN12616000726459. Registered on 02 June 2016. Universal Trial Number (UTN) U1111-1181-7087.

Associations between suprapatellar pouch effusion-synovitis, serum cartilage oligomeric matrix protein, high sensitivity C-reaction protein, knee symptom, and joint structural changes in patients with knee osteoarthritis

OBJECTIVES

To investigate the cross-sectional associations between suprapatellar pouch effusion-synovitis and serum levels of cartilage oligomeric matrix protein (COMP), high sensitivity C-reaction protein (hs-CRP), knee symptom, and structural changes in patients with symptomatic knee osteoarthritis (OA).

METHOD

A total of 173 subjects were included. The osteophytes, joint space narrowing (JSN), and radiographic severity of OA were determined using X-ray. Cartilage defects, bone marrow lesions (BMLs), and suprapatellar pouch effusion-synovitis were assessed using magnetic resonance imaging. Serum levels of COMP and hs-CRP were measured by enzyme-linked immunosorbent assay. The knee joint symptom was self-reported using visual analogue scale.

RESULTS

In this OA cohort, after adjustment for age, sex, and BMI, the presence of pathological effusion-synovitis was associated with serum levels of COMP (β: 30.98, P = 0.018), and suprapatellar pouch effusion-synovitis maximum areas were associated with serum hs-CRP levels. Both suprapatellar pouch effusion-synovitis maximum area and grade were associated with osteophytes and Kellgren-Lawrence scores (ORs: 1.29-1.54, all P < 0.05). In patients with high tertile of hs-CRP, both suprapatellar pouch effusion-synovitis maximum area and grade were associated with cartilage defects at lateral and medial tibiofemoral sites (ORs: 3.01-8.41, all P < 0.05) after adjustment for covariates. In female patients, the significant associations were present between suprapatellar pouch effusion-synovitis and medial tibiofemoral BMLs (ORs: 1.43-1.53, all P < 0.05) after adjustment for covariates.

CONCLUSIONS

Suprapatellar pouch effusion-synovitis was associated with serum levels of COMP as well as hs-CRP and knee structural abnormalities in patients with knee OA. These suggested that effusion-synovitis may play a role in knee OA.Key Points• Suprapatellar pouch effusion-synovitis is associated with serum levels of COMP in patients with knee OA.• Suprapatellar pouch effusion-synovitis is associated with cartilage defects in knee OA patients with high systemic inflammation.

Knee effusion volume assessed by magnetic resonance imaging and progression of knee osteoarthritis: data from the Osteoarthritis Initiative

Objective

To examine whether baseline knee joint effusion volume and the change in effusion volume over 1 year are associated with cartilage volume loss, progression of radiographic OA (ROA) over 4 years and risk of total knee replacement over 6 years.

Methods

This study included 4115 Osteoarthritis Initiative participants with knee joint effusion volume quantified by MRI at baseline. The change in effusion volume over 1 year was assessed. Cartilage volume loss and progression of ROA over 4 years were assessed using MRI and X-ray and total knee replacement over 6 years was assessed. Multiple linear regression and binary logistic regression were used for data analyses.

Results

Baseline knee effusion volume (per 5 ml) was positively associated with a loss of medial and lateral cartilage volume [regression coefficient 0.13%/year (95% CI 0.10, 0.17) and 0.13%/year (95% CI 0.10, 0.16), respectively, both P < 0.001], progression of ROA [odds ratio (OR) 1.28 (95% CI 1.20, 1.37), P < 0.001], and risk of knee replacement [OR 1.12 (95% CI 1.05, 1.20), P = 0.001]. A 5 ml increase in knee effusion volume over 1 year was positively associated with medial cartilage volume loss [regression coefficient 0.09%/year (95% CI 0.04, 0.15), P = 0.001], progression of ROA [OR 1.21 (95% CI 1.11, 1.33), P < 0.001] and risk of knee replacement [OR 1.24 (95% CI 1.12, 1.37), P < 0.001].

Conclusions

Knee joint effusion volume assessed from MRI provides a continuous and sensitive measure that was associated with cartilage volume loss, progression of ROA and risk of total knee replacement. It may provide a method to identify individuals with an inflammatory OA phenotype who are at higher risk of disease progression.

Optimization of TGF-β1-transduced chondrocytes for cartilage regeneration in a 3D printed knee joint model

A cell therapy product of transforming growth factor (TGF)-β1-transduced chondrocytes has been commercialized to treat osteoarthritis of the knee via intra-articular injection. The need for arthroscopic application of the cells to simultaneously treat intra-articular pathologies of knee osteoarthritis is increasingly urgent. The purpose of this study was to optimize TGF-β1-transduced chondrocytes for arthroscopic application. The optimal composition of chondrocytes and thrombin was initially determined by measuring the consolidation time of a diverse ratio of chondrocytes and thrombin mixed with 1 ml of fibrinogen. The consolidation time of the diverse ratio of fibrinogen and atelocollagen mixed with the determined optimal ratio of chondrocytes and thrombin was evaluated. The mixture of the determined optimal ratio of TGF-β1-transduced chondrocytes, atelocollagen, fibrinogen, and thrombin was applied to the cartilage defect of the 3D printed knee joint model arthroscopically. The status of the mixture in the defect was then evaluated. Chondrogenic activities of TGF-β1-transduced chondrocytes mixed with atelocollagen were evaluated. The determined ratio of TGF-β1-transduced chondrocytes to thrombin was 8:2 and that of fibrin to atelocollagen was also 8:2. Excellent maintenance of conformation of the mixture of TGF-β1-transduced chondrocytes, atelocollagen, fibrinogen, and thrombin in the cartilage defect of the 3D printed knee joint model was observed arthroscopically. Increased chondrogenic activities were observed in the group of TGF-β1-transduced chondrocytes mixed with atelocollagen. TGF-β1-transduced chondrocytes can be applied arthroscopically to treat cartilage defects of the knee at an optimized mixing ratio of atelocollagen, fibrinogen, and thrombin.

Osteoarthritis year in review 2018: imaging

PURPOSE

To provide a narrative review of the most relevant original research published in 2017/2018 on osteoarthritis imaging.

METHODS

The PubMed database was used to recover all relevant articles pertaining to osteoarthritis and medical imaging published between 1 April 2017 and 31 March 2018. Review articles, case studies and in vitro or animal studies were excluded. The original publications were subjectively sorted based on relevance, novelty and impact.

RESULTS AND CONCLUSIONS

The publication search yielded 1,155 references. In the assessed publications, the most common imaging modalities were radiography (N = 708) and magnetic resonance imaging (MRI) (355), followed by computed tomography (CT) (220), ultrasound (85) and nuclear medicine (17). An overview of the most important publications to the osteoarthritis (OA) research community is presented in this narrative review. Imaging studies play an increasingly important role in OA research, and have helped us to understand better the pathophysiology of OA. Radiography and MRI continue to be the most applied imaging modalities, while quantitative MRI methods and texture analysis are becoming more popular. The value of ultrasound in OA research has been demonstrated. Several multi-modality predictive models have been developed. Deep learning has potential for more automatic and standardized analyses in future OA imaging research.

Effects of ultrasound therapy on the synovial fluid proteome in a rabbit surgery-induced model of knee osteoarthritis

Background

Ultrasound (US) therapy may improve osteoarthritis symptoms. We investigated the effects of US on the synovial fluid (SF) proteome in a rabbit knee osteoarthritis (KOA) model to explore its therapeutic mechanisms.

Methods

Sixteen healthy 6-month-old New Zealand white rabbits (eight male, eight female), weighing 2.5–3.0 kg, were randomly divided into groups A and B with eight rabbits per group. Both groups were subjected to right anterior cruciate ligament transaction. Six weeks after surgery, we treated the operated knee joint of group A rabbits with US and of group B rabbits with sham US for 2 weeks. The proteomes of knee joint SF from groups A and B rabbits were then analyzed using a label-free mass spectrometry (MS) quantification method.

Results

We identified 19 protein sequences annotated by 361 Gene Ontology (GO) items. According to the Kyoto Encyclopedia of Genes and Genomes (KEGG) database of rabbit protein sequences, we then annotated the KO numbers of homologous/similar proteins to 32 relevant KEGG pathways. We extracted 10 significantly differentially expressed proteins among the 32 relevant KEGG messages/metabolism pathways. The proteins whose levels were decreased were apolipoprotein A-I (AopA-1), transferrin (TF), carboxypeptidase B2 (CBP2), arylesterase/paraoxonase (PON), fibrinogen alpha chain, and alpha-2-macroglobulin (A2M). The proteins whose levels were increased were molecular chaperone HtpG/heat shock proteins (htpG, HSP90A), decorin (DCN), pyruvate kinase (PK, pyk), and fatty acid-binding protein 4/adipocyte (FABP4, aP2).

Conclusions

US therapy can alter protein levels in SF, which can decrease AopA-1, TF, CBP2, PON, fibrinogen alpha chain and A2M protein levels, and increase HtpG/HSP90A, DCN, PK/PKY, and FABP4/aP2 protein levels in SF of KOA, suggesting that the therapeutic mechanisms of US therapy on KOA may occur through changes in the SF proteome.

Mitochondrial DNA haplogroups associated with MRI-detected structural damage in early knee osteoarthritis

OBJECTIVE

Magnetic resonance imaging (MRI)-detected structural features are associated with increased risk of radiographic osteoarthritis (ROA). Specific mitochondrial DNA (mtDNA) haplogroups have been associated with incident ROA. Our objective was to compare the presence of MRI-detected structural features across mtDNA haplogroups among knees that developed incident ROA.

DESIGN

Knees from the Osteoarthritis Initiative (OAI) that developed incident ROA during 48 months follow-up were identified from Caucasian participants. mtDNA haplogroups were assigned based on a single base extension assay. MRIs were obtained annually between baseline and 4-year follow-up and scored using the MRI Osteoarthritis Knee Score (MOAKS). The association between mtDNA haplogroups and MRI-detected structural features was estimated using log-binomial regression. Participants who carried haplogroup H served as the reference group.

RESULTS

The sample included 255 participants contributing 277 knees that developed ROA. Haplogroups included H (116, 45%), J (17, 7%), T (26, 10%), Uk (61, 24%), and the remaining less common haplogroups ("others") (35, 14%). Knees of participants with haplogroup J had significantly lower risk of medium/large bone marrow lesions (BMLs) in the medial compartment [3.2%, relative risks (RR) = 0.17; 95%CI: 0.05, 0.64; P = 0.009] compared to knees of participants who carried haplogroup H [16.3%], as did knees from participants within the "others" group [2.8%, RR = 0.20; 95%CI: 0.08, 0.55; P = 0.002], over the 4 year follow-up period.

CONCLUSIONS

mtDNA haplogroup J was associated with lower risk of BMLs in the medial compartment among knees that developed ROA. Our results offer a potential hypothesis to explain the mechanism underlying the previously reported protective association between haplogroup J and ROA.