Bone mineral density is not associated with incident high-intensity back pain: a 10-year cohort study in men.

Although patients believe that osteoporosis is a painful condition, health professionals assume it is painless unless a fracture occurs. The association between BMD and back pain has not been examined longitudinally in community-based adults in an unbiased population using gold-standard measures. This study aimed to examine the association between BMD and incident high-intensity back pain and/or high disability over 10 years in Australian men without high-intensity symptoms at baseline. Men with no high-intensity back pain and/or high disability attending the Geelong Osteoporosis Study at the 5-year visit (occurring between 2006-2010) (considered the baseline for the current study) were followed for 10 years (reassessed between 2016-2021). Back pain and disability were assessed using the Graded Chronic Pain Scale at both time points. At baseline, DXA was used to measure lumbar spine and total hip BMD and spinal artefacts. The relationships between BMD and incident high-intensity pain and/or high disability at follow-up were examined using binary logistic regression, adjusted for age, body mass index, depression, education, smoking, mobility, and spinal artefacts. A total of 679 participants had no to low-intensity pain and/or no to low disability at baseline. A total of 441 attended follow-up, providing back pain and disability data. Thirty-seven men developed high-intensity pain and/or high disability. No association of BMD at any site was seen with incident high-intensity pain and/or high disability. BMD was not associated with incident high-intensity pain or disability in community-based men. These data provide evidence to dispel the erroneous community-held belief that low BMD is related to back pain and disability.

Krill Oil for Knee Osteoarthritis: A Randomized Clinical Trial.

Importance: Knee osteoarthritis is disabling, with few effective treatments. Preliminary evidence suggested that krill oil supplementation improved knee pain, but effects on knee osteoarthritis remain unclear. Objective: To evaluate efficacy of krill oil supplementation, compared with placebo, on knee pain in people with knee osteoarthritis who have significant knee pain and effusion-synovitis. Design, Setting, and Participants: Multicenter, randomized, double-blind, placebo-controlled clinical trial in 5 Australian cities. Participants with clinical knee osteoarthritis, significant knee pain, and effusion-synovitis on magnetic resonance imaging were enrolled from December 2016 to June 2019; final follow-up occurred on February 7, 2020. Interventions: Participants were randomized to 2 g/d of krill oil (n = 130) or matching placebo (n = 132) for 24 weeks. Main Outcomes and Measures: The primary outcome was change in knee pain as assessed by visual analog scale (range, 0-100; 0 indicating least pain; minimum clinically important improvement = 15) over 24 weeks. Results: Of 262 participants randomized (mean age, 61.6 [SD, 9.6] years; 53% women), 222 (85%) completed the trial. Krill oil did not improve knee pain compared with placebo (mean change in VAS score, -19.9 [krill oil] vs -20.2 [placebo]; between-group mean difference, -0.3; 95% CI, -6.9 to 6.4) over 24 weeks. One or more adverse events was reported by 51% in the krill oil group (67/130) and by 54% in the placebo group (71/132). The most common adverse events were musculoskeletal and connective tissue disorders, which occurred 32 times in the krill oil group and 42 times in the placebo group, including knee pain (n = 10 with krill oil; n = 9 with placebo), lower extremity pain (n = 1 with krill oil; n = 5 with placebo), and hip pain (n = 3 with krill oil; n = 2 with placebo). Conclusions and Relevance: Among people with knee osteoarthritis who have significant knee pain and effusion-synovitis on magnetic resonance imaging, 2 g/d of daily krill oil supplementation did not improve knee pain over 24 weeks compared with placebo. These findings do not support krill oil for treating knee pain in this population. Trial Registration: Australian New Zealand Clinical Trials Registry Identifier: ACTRN12616000726459; Universal Trial Number: U1111-1181-7087.

Efficacy of tumor necrosis factor inhibitors in hand osteoarthritis: A systematic review and meta-analysis of randomized controlled trials.

Objectives: This study aimed at systematically review the evidence for the efficacy of Tumor Necrosis Factor (TNF) inhibitors on symptoms and structural outcomes in hand osteoarthritis. Methods: Three databases were searched for randomized controlled trials examining the efficacy of TNF inhibitors in hand osteoarthritis. Two authors extracted data and assessed the risk of bias. The mean difference (MD) was calculated, and a random-effects meta-analysis was performed. Results: Four studies were identified involving 276 participants. Meta-analysis showed that TNF inhibitors had no effect on pain at 4-6 weeks (MD -0.93, 95%CI -7.41 to 5.55; 2 studies) and 24-26 weeks (MD -3.82, 95%CI -11.46 to 3.83; 2 studies) and no effect on grip strength at 12 months (MD -0.35, 95%CI -1.08 to 0.37; 2 studies). There was limited evidence for the effect of TNF inhibitors on structural outcomes at 12 months. Subgroup analysis from 2 studies showed beneficial effect of TNF inhibitors on reducing the progression of structural outcomes in hand OA patients with signs of inflammation but not in those without inflammation. The certainty of the evidence was low for the effect of TNF inhibitor on pain and moderate for the effect on grip strength. Conclusion: This study found no effect of TNF inhibitors on clinical outcomes in hand osteoarthritis over the short term (<6 weeks) and within one year, with some evidence for beneficial effect on structural outcomes.

Functional outcomes following knee replacement in community-dwelling older adults.

BACKGROUND: Knee replacements are increasingly performed in older adults but uncertainty remains regarding their benefits in the context of age-related decline in physical function and other comorbidities. This study aimed to examine (1) the effect of knee replacement on functional outcomes in the context of age-related decline in physical function and (2) the factors associated with minimal important improvement in physical function after knee replacement in community-dwelling older adults aged ≥ 70 years. METHODS: This cohort study was performed within the ASPREE trial, with 889 participants undergoing knee replacement during the trial and 858 age- and sex-matched controls without knee or hip replacement identified from 16,703 Australian participants aged ≥ 70 years. Health-related quality of life was assessed annually using the SF-12, including its physical and mental component summary (PCS and MCS). Gait speed was measured biennially. Multiple linear regression and analysis of covariance were used to adjust for potential confounders. RESULTS: Participants with knee replacement had significantly lower pre- and post-replacement PCS scores and gait speed compared with age- and sex-matched controls. Participants with knee replacement had significant improvement in PCS score following knee replacement (mean change 3.6, 95% CI 2.9-4.3) while PCS score remaining unchanged in age- and sex-matched controls (-0.02, 95% CI -0.6 to 0.6) during follow-up period. The greatest improvements were observed for bodily pain and physical function. Following knee replacement, 53% of participants experienced minimal important improvement in PCS score (increased by ≥ 2.7), while 24% experienced worsened PCS score (reduced by > 2.7). Participants experiencing improved PCS score postoperatively had significantly lower PCS and higher MCS scores pre-surgery. CONCLUSIONS: Although community-based older adults experienced a significant improvement in PCS scores after knee replacement, their postoperative physical functional status remained significantly lower than age- and sex-matched controls. The degree of preoperative physical function impairment was a strong predictor of functional improvement, suggesting that this could be an important consideration when identifying older people most likely to benefit from knee replacement surgery.

Association between popliteal artery wall thickness and structural progression in patients with symptomatic knee osteoarthritis.

OBJECTIVE: There is increasing evidence for the involvement of vascular disease in the pathogenesis of knee OA. Popliteal artery wall thickness can be used as a surrogate marker of atherosclerosis. We examined the association between popliteal artery wall thickness and knee cartilage volume in individuals with symptomatic knee OA. METHODS: This prospective cohort study analysed 176 participants from a randomized placebo-controlled trial examining the effect of atorvastatin on structural progression in knee OA. The participants underwent MRI of the study knee at baseline and 2-year follow-up. Popliteal artery wall thickness and tibial cartilage volume were measured from MRI using validated methods. The top quartile of the rate of tibial cartilage volume loss was defined as rapid progression. RESULTS: At baseline, every 10% increase in popliteal artery wall thickness was associated with 120.8 mm3 (95% CI 5.4, 236.2, P = 0.04) lower of medial tibial cartilage volume and 151.9 mm3 (95% CI 12.1, 291.7, P = 0.03) lower of lateral tibial cartilage volume. Longitudinally, for every 10% increase in popliteal artery wall thickness, the annual rate of medial tibial cartilage volume loss was increased by 1.14% (95% CI 0.09%, 2.20%, P = 0.03), and there was a 2.28-fold (95% CI 1.07, 4.83, P = 0.03) risk of rapid progression of medial tibial cartilage loss, adjusted for age, sex, BMI, tibial bone area, smoking, vigorous physical activity, and intervention group allocation. CONCLUSION: The findings support a role for vascular pathology in the progression of knee OA. Targeting atherosclerosis has the potential to improve outcomes in knee OA.

Osteophytes mediate the associations between cartilage morphology and changes in knee symptoms in patients with knee osteoarthritis.

AIMS: To investigate whether the associations between cartilage defects and cartilage volumes with changes in knee symptoms were mediated by osteophytes. METHODS: Data from the Vitamin D Effects on Osteoarthritis (VIDEO) study were analyzed as a cohort. The Western Ontario and McMaster Universities Osteoarthritis Index was used to assess knee symptoms at baseline and follow-up. Osteophytes, cartilage defects, and cartilage volumes were measured using magnetic resonance imaging at baseline. Associations between cartilage morphology and changes in knee symptoms were assessed using linear regression models, and mediation analysis was used to test whether these associations were mediated by osteophytes. RESULTS: A total of 334 participants (aged 50 to 79 years) with symptomatic knee osteoarthritis were included in the analysis. Cartilage defects were significantly associated with change in total knee pain, change in weight-bearing pain, and change in non-weight-bearing pain after adjustment for age, sex, body mass index, and intervention. Cartilage volume was significantly associated with change in weight-bearing pain and change in physical dysfunction after adjustment. Lateral tibiofemoral and patellar osteophyte mediated the associations of cartilage defects with change in total knee pain (49-55%) and change in weight-bearing pain (61-62%) and the association of cartilage volume with change in weight-bearing pain (27-30%) and dysfunction (24-25%). Both cartilage defects and cartilage volume had no direct effects on change in knee symptoms. CONCLUSIONS: The significant associations between cartilage morphology and changes in knee symptoms were indirect and were partly mediated by osteophytes.

Functional Outcomes Following Hip Replacement in Community-Dwelling Older Adults.

Uncertainty remains regarding the benefit of hip replacement in older adults in the context of age-related decline in physical function. This study aimed to examine the effect of hip replacement on functional outcomes and identify factors associated with clinically important improvement in physical function postoperatively in community-dwelling older adults. This cohort study was performed within the ASPREE trial, with 698 participants receiving hip replacement and 677 age- and sex-matched controls without knee or hip replacement during the trial drawn from 16,703 Australian participants aged ≥70 years. Health status (physical and mental component summary [PCS and MCS]) was assessed annually using the SF-12. Participants receiving hip replacement had significantly lower pre- and post-replacement PCS scores compared with controls (p < 0.0001). There was significant improvement in PCS score following hip replacement (mean change 4.9, 95%CI 4.0−5.7) but no change in controls (0.01, 95%CI −0.7−0.7). Following hip replacement, 46.7% of participants experienced clinically important improvement in PCS score, while 15.5% experienced worsened PCS score. Participants experiencing improved postoperative PCS score had significantly lower PCS and higher MCS scores preoperatively. The degree of preoperative physical function impairment was a significant indicator of older people most likely to benefit from hip replacement surgery.

Association Between Low-Dose Methotrexate Exposure and Melanoma: A Systematic Review and Meta-analysis.

Importance: Methotrexate is widely used for the treatment of inflammatory disorders, including rheumatoid arthritis. Studies suggest that methotrexate may be associated with an increased risk of melanoma. Objective: To determine whether methotrexate exposure is associated with an increased risk of cutaneous melanoma. Data Sources: MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov were searched from inception to May 12, 2022, for eligible studies. Study Selection: Case-control studies, cohort studies, or randomized clinical trials (RCTs) were included if they examined the odds or risk of cutaneous melanoma in individuals exposed to low-dose methotrexate in comparison with individuals unexposed. No language limitations were applied. Data Extraction and Synthesis: Two independent reviewers extracted data on study characteristics and outcome data. The Meta-analysis of Observational Studies in Epidemiology guidelines were followed. To assess study quality, the Cochrane risk of bias tool was used for RCTs, and the Joanna Briggs Institute Checklist was used for cohort and case-control studies. Odds ratio from case-control studies and relative risk or hazard ratio from cohort studies or RCTs were pooled, and a random-effects model meta-analysis was conducted. Main Outcomes and Measures: Prespecified outcome was the odds ratio, hazard ratio, or risk ratio of cutaneous melanoma comparing low-dose methotrexate exposure with nonexposure. Results: Seventeen studies (8 RCTs, 5 cohort studies, 4 case-control studies) were eligible for inclusion, and of these, 12 studies with 16 642 cases of melanoma were pooled in the primary analysis. Indications for methotrexate included rheumatoid arthritis, psoriasis, psoriatic arthritis, and inflammatory bowel disease and were unknown in 5 studies. Compared with unexposed individuals, study participants with methotrexate exposure had a small increased risk of melanoma (pooled relative risk, 1.15; 95% CI, 1.08-1.22), but this did not persist in a sensitivity analysis excluding the largest study (pooled relative risk, 1.11; 95% CI, 1.00-1.24). Subgroup analyses according to comparator group (comparing methotrexate exposure with either immunomodulator alone vs immunomodulator and methotrexate) or the indication for methotrexate being rheumatoid arthritis provided similar risk estimates. Using geographical population melanoma incidence rates, a number needed to harm of 18 630 was calculated in Australia, and 41 425 in North America. Conclusions and Relevance: In this systematic review and meta-analysis, low-dose methotrexate exposure was associated with an increased melanoma risk, but the absolute risk increase could be considered negligible.

Association between clusters of back and joint pain with opioid use in middle-aged community-based women: a prospective cohort study.

BACKGROUND: To determine the relationship between clusters of back pain and joint pain and prescription opioid dispensing. METHODS: Of 11,221 middle-aged participants from the Australian Longitudinal Study of Women's Health, clusters of back pain and joint pain from 2001 to 2013 were identified using group-based trajectory modelling. Prescription opioid dispensing from 2003 to 2015 was identified by linking the cohort to Pharmaceutical Benefit Scheme dispensing data. Multinomial logistic regression was used to examine the association between back pain and joint pain clusters and dispensing of prescription opioids. The proportion of opioids dispensed in the population attributable to back and join pain was calculated. RESULTS: Over 12 years, 68.5 and 72.0% women reported frequent or persistent back pain and joint pain, respectively. There were three clusters ('none or infrequent', 'frequent' and 'persistent') for both back pain and joint pain. Those in the persistent back pain cluster had a 6.33 (95%CI 4.38-9.16) times increased risk of having > 50 opioid prescriptions and those in persistent joint pain cluster had a 6.19 (95%CI 4.18-9.16) times increased risk of having > 50 opioid prescriptions. Frequent and persistent back and joint pain clusters together explained 41.7% (95%CI 34.9-47.8%) of prescription opioid dispensing. Women in the frequent and persistent back pain and joint pain clusters were less educated and reported more depression and physical inactivity. CONCLUSION: Back pain and joint pain are major contributors to opioid prescription dispensing in community-based middle-aged women. Additional approaches to reduce opioid use, targeted at those with frequent and persistent back pain and joint pain, will be important in order to reduce the use of opioids and their consequent harm in this population.

The association between change in bone marrow lesion size and change in tibiofemoral cartilage volume and knee symptoms.

OBJECTIVE: To describe the association between change in subchondral bone marrow lesions (BMLs) and change in tibiofemoral cartilage volume and knee symptoms in patients with symptomatic knee OA. METHODS: In total, 251 participants (mean 61.7 years, 51% female) were included. Tibiofemoral cartilage volume was measured at baseline and 24 months, and BML size at baseline, 6 and 24 months. Knee pain and function scores were evaluated at baseline, 6 and 24 months. Change in total and compartment-specific BML size was categorized according to the Least Significance Criterion. Linear mixed-effects models were used to evaluate the associations of change in BMLs over 6 and 24 months with change in cartilage volume over 24 months and knee symptoms over 6 and 24 months. RESULTS: Total BML size enlarged in 26% of participants, regressed in 31% and remained stable in 43% over 24 months. Compared with stable BMLs in the same compartment, enlarging BMLs over 24 months were associated with greater cartilage loss (difference: -53.0mm3, 95% CI: -100.0, -6.0), and regressing BMLs were not significantly associated with reduced cartilage loss (difference: 32.4mm3, 95% CI: -8.6, 73.3) over 24 months. Neither enlargement nor regression of total BML size over 6 and 24 months was associated with change in knee pain and function over the same time intervals. CONCLUSIONS: In subjects with symptomatic knee osteoarthritis and BMLs, enlarging BMLs may lead to greater cartilage loss but regressing lesions are not associated with reduced cartilage loss while neither is associated with change in knee symptoms.

Effect of Stem Cell Injections on Osteoarthritis-related Structural Outcomes: A Systematic Review.

OBJECTIVE: To systematically review the evidence for the efficacy of mesenchymal stem cell (MSC) injections in improving osteoarthritis (OA)-related structural outcomes. METHODS: Ovid Medline and EMBASE were searched from their inceptions to April 2020 using MeSH terms and key words. Independent reviewers extracted data and assessed methodological quality. Qualitative evidence synthesis was performed due to the heterogeneity of interventions and outcome measures. RESULTS: Thirteen randomized controlled trials (phase I or II) were identified: 10 in OA populations and 3 in populations at risk of OA, with low (n = 9), moderate (n = 3), or high (n = 1) risk of bias. Seven studies used allogeneic MSCs (4 bone marrow, 1 umbilical cord, 1 placenta, 1 adipose tissue), 6 studies used autologous MSCs (3 adipose tissue, 2 bone marrow, 1 peripheral blood). Among the 11 studies examining cartilage outcomes, 10 found a benefit of MSCs on cartilage volume, morphology, quality, regeneration, and repair, assessed by magnetic resonance imaging, arthroscopy, or histology. The evidence for subchondral bone was consistent in all 3 studies in populations at risk of OA, showing beneficial effects. Sixteen unpublished, eligible trials were identified by searching trial registries, including 8 with actual or estimated completion dates before 2016. CONCLUSION: Our systematic review of early-phase clinical trials demonstrated consistent evidence of a beneficial effect of intraarticular MSC injections on articular cartilage and subchondral bone. Due to the heterogeneity of MSCs, modest sample sizes, methodological limitations, and potential for publication bias, further work is needed before this therapy is recommended in the management of OA.

Rates, costs and determinants of lumbar spine imaging in population-based women born in 1973-1978: Data from the Australian Longitudinal Study on Women's Health.

OBJECTIVE: There are concerns that lumbar spine imaging represents low value care. Our aim was to examine the use of lumbar spine imaging [radiography, computed tomography (CT), magnetic resonance imaging (MRI)] over 20 years, and costs and person-level characteristics of imaging in a large cohort of Australian women. METHODS: The Australian Longitudinal Study on Women's Health (ALSWH) is a longitudinal population-based survey of women randomly selected from national health insurance scheme (Medicare) database. This study examined 13458 women born in 1973-1978 who consented to link their ALSWH and Medical Benefits Scheme records. Self-reported data on demographics, body mass index, depression, physical and mental health, and back pain were collected in each survey performed in 1996, 2000, 2003, 2006, 2009, 2012, and 2015. Data on lumbar spine imaging from 1996 to 2015 were obtained from the Medical Benefits Scheme database. RESULTS: 38.9% of women underwent some form of lumbar spine imaging over 20 years. While radiography increased from 1996 to 2011 and decreased thereafter, CT and MRI continued to increase from 1996 to 2015. In women with self-reported back pain, depression and poorer physical health were associated with imaging, with no significant differences in types of imaging. Based on imaging rates in ALSWH, the estimated costs for Australian women aged 30-39 years were AU$51,735,649 over 2011-2015. CONCLUSIONS: Lumbar spine imaging was common in population-based Australian women, with rates increasing over 20 years. Depression and poor physical health were associated with lumbar spine imaging. Raising awareness of this in clinicians is likely to result in significant cost savings if clinical guidelines are followed, with the potential of freeing resources for high value care and health outcomes.

Effect of Intravenous Zoledronic Acid on Tibiofemoral Cartilage Volume Among Patients With Knee Osteoarthritis With Bone Marrow Lesions: A Randomized Clinical Trial.

Importance: A proof-of-principle study suggested that intravenous zoledronic acid may reduce knee pain and the size of bone marrow lesions in people with knee osteoarthritis, but data from large trials are lacking. Objective: To determine the effects of intravenous zoledronic acid on knee cartilage volume loss in patients with symptomatic knee osteoarthritis and bone marrow lesions. Design, Setting, and Participants: A 24-month multicenter, double-blind placebo-controlled randomized clinical trial conducted at 4 sites in Australia (1 research center and 3 hospitals). Adults aged 50 years or older with symptomatic knee osteoarthritis and subchondral bone marrow lesions detected by magnetic resonance imaging (MRI) were enrolled from November 2013 through September 2015. The final date of follow-up was October 9, 2017. Interventions: Intravenous infusion with either 5 mg of zoledronic acid in a 100-mL saline solution (n = 113) or a placebo saline solution (n = 110) at baseline and 12 months. Main Outcomes and Measures: The primary outcome was absolute change in tibiofemoral cartilage volume assessed using MRI over 24 months (the minimum clinically important difference [MCID] has not been established). Three prespecified secondary outcomes were change in knee pain assessed by a visual analog scale (0 [no pain] to 100 [unbearable pain]; MCID, 15) and the Western Ontario and McMaster Universities Osteoarthritis Index (0 [no pain] to 500 [unbearable pain]; MCID, 75) over 3, 6, 12, 18, and 24 months and change in bone marrow lesion size over 6 and 24 months (the MCID has not been established). Results: Of 223 participants enrolled (mean age, 62.0 years [SD, 8.0 years]; 52% were female), 190 (85%) completed the trial. Change in tibiofemoral cartilage volume was not significantly different between the zoledronic acid group and the placebo group over 24 months (-878 mm3 vs -919 mm3; between-group difference, 41 mm3 [95% CI, -79 to 161 mm3]; P = .50). No significant between-group differences were found for any of the prespecified secondary outcomes, including changes in knee pain assessed by a visual analog scale (-11.5 in the zoledronic acid group vs -16.8 in the placebo group; between-group difference, 5.2 [95% CI, -2.3 to 12.8]; P = .17), changes in knee pain assessed by the Western Ontario and McMaster Universities Osteoarthritis Index (-37.5 vs -58.0, respectively; between-group difference, 20.5 [95% CI, -11.2 to 52.2]; P = .21), and changes in bone marrow lesion size (-33 mm2 vs -6 mm2; between-group difference, -27 mm2 [95% CI, -127 to 73 mm2]; P = .60) over 24 months. Adverse events were more common with zoledronic acid than with placebo (96% vs 83%, respectively) and consisted mainly of acute reactions (defined as symptoms within 3 days of administration of infusion; 87% vs 56%). Conclusions and Relevance: Among patients with symptomatic knee osteoarthritis and bone marrow lesions, yearly zoledronic acid infusions, compared with placebo, did not significantly reduce cartilage volume loss over 24 months. These findings do not support the use of zoledronic acid in the treatment of knee osteoarthritis. Trial Registration: anzctr.org.au Identifier: ACTRN12613000039785.

Higher Serum Levels of Resistin Are Associated With Knee Synovitis and Structural Abnormalities in Patients With Symptomatic Knee Osteoarthritis.

OBJECTIVE: Resistin acts as an endogenous ligand of Toll-like receptor (TLR)-4 that triggers major inflammatory pathways and mediates inflammatory processes. The role of resistin in osteoarthritis (OA) pathogenesis is unclear. The aim of this study is to describe the longitudinal associations of serum levels of resistin with knee synovitis measures and structural abnormalities in patients with knee OA. DESIGN: A prospective cohort study. SETTING AND PARTICIPANTS: Patients (n = 200) with symptomatic knee OA (mean age 63.1 years, range 49-79; female 46.5%) participated. MEASURES: All measures were performed at baseline and 2 years later. Serum resistin was measured using enzyme-linked immunosorbent assay. Infrapatellar fat pad (IPFP) high signal intensity alteration and effusion synovitis were measured from magnetic resonance imaging (MRI). Knee structures including cartilage volume, cartilage defects, and bone marrow lesions (BMLs) were also assessed by MRI semiquantitatively or quantitatively. Linear or logistic mixed effects regression analyses were used in longitudinal analyses. RESULTS: Serum resistin was positively associated with high signal intensity alteration measures of IPFP as well as the presence [relative risk = 1.06, 95% confidence interval (CI) 1.02, 1.10] and volume (ß = 0.77, 95% CI 0.01, 1.53) of effusion synovitis in multivariable analyses. Serum levels of resistin were also positively associated with higher tibiofemoral cartilage defect (ß = 1.98, 95% CI 0.34, 3.57) and BML scores (ß = 3.18, 95% CI 0.99, 5.37) after adjustment for covariates. CONCLUSION AND IMPLICATIONS: Higher serum levels of resistin are associated with knee synovitis surrogate measures and structural abnormalities, suggesting that obesity may promote OA not only by increasing weight loading on joints but also by triggering 1 or more inflammatory pathways.

Association Between Quantitatively Measured Infrapatellar Fat Pad High Signal-Intensity Alteration and Magnetic Resonance Imaging-Assessed Progression of Knee Osteoarthritis.

OBJECTIVE: To describe the cross-sectional and longitudinal associations between quantitative measures of infrapatellar fat pad (IPFP) signal-intensity alteration and knee structural abnormalities in patients with symptomatic knee osteoarthritis (OA). METHODS: A total of 261 patients (mean ± SD age 63.0 ± 7.2 years) with symptomatic knee OA were selected from a randomized controlled trial with a follow-up of 2 years. IPFP signal-intensity alterations at baseline were quantitatively measured on T2-weighted fat-saturated magnetic resonance imaging using MATLAB. These quantitative measures included the SD of whole IPFP signal intensity measurement, the upper quartile value of high signal intensity (UQH ), the ratio of volume of high signal-intensity alteration to volume of whole IPFP (percentageH ), and the clustering effect of high signal intensity (clustering-factorH ). Cartilage volume and defects and bone marrow lesions (BMLs) were assessed using validated measures. RESULTS: Higher baseline SD of the IPFP, UQH , and clustering-factorH were associated with greater loss of tibial cartilage volume and larger increases in tibiofemoral cartilage defects over 2 years. Patients with high and medium tertiles of clustering-factorH had greater loss of cartilage volume per annum compared with those with a low tertile (for high 4.9%, for medium 4.6%, and for low 3.3% annually). Baseline percentageH and clustering-factorH were positively and significantly associated with increases in tibiofemoral BMLs over 2 years. Cross-sectional associations between IPFP measures and knee structures were similar but more consistent. CONCLUSION: Quantitative measures of increased signal intensity in the IPFP were associated with knee structural abnormalities in the tibiofemoral compartment, suggesting that these measurements could be used as an additional entry criterion to enrich studies for faster progressors of knee OA.

Vitamin D supplements for trunk muscle morphology in older adults: secondary analysis of a randomized controlled trial.

BACKGROUND: The effect of vitamin D supplementation on postural muscles of the trunk is of particular interest because low 25-hydroxyvitamin D [25(OH) D] levels are associated with decreased postural balance and increased risk of falls. Understanding the role of vitamin D supplementation plays in trunk muscle function of older adults is necessary, as this is a potentially modifiable factor to improve postural muscle function and decrease the risk of falling of older adults. The objective of this randomized controlled trial was to evaluate the effect of 12 months of vitamin D supplementation compared with placebo, on morphology and function of the trunk muscles of adults aged 50 to 79 years with low serum 25(OH) D levels. METHODS: This was a secondary analysis of a randomized, placebo-controlled, and double-blind clinical trial conducted between June 2010 and December 2013 in Tasmania, Australia. The clinical trial was registered with the Australian New Zealand clinical trial registration agency, ClinicalTrials.gov identifier: NCT01176344; Australian New Zealand Clinical Trials Registry: ACTRN 12610000495022. Participants were aged 50-79 years with ongoing symptoms of knee osteoarthritis and with low serum [25(OH) D] (12.5 to 60 nmol/L, 5.2 to 24 ng/mL). Participants were randomly assigned to either monthly 50 000 IU oral vitamin D3 (n = 104) or an identical placebo (n = 113) for 24 months as per clinical trial protocol. The primary outcomes in this pre-specified secondary analysis were between-group differences in change in size of rectus abdominis, transversus abdominis, internal oblique, external oblique, and lumbar multifidus muscles and function (assessed by change in thickness on contraction) of these muscles (excepting rectus abdominis) from baseline to 12 months. Muscle size was assessed using ultrasound imaging. RESULTS: Of 217 participants (mean age 63 years, 48% women), 186 (85.7%) completed the study. There were no significant between-group differences in change in size or function of the abdominal or multifidus muscles after 12 months of vitamin D supplementation. CONCLUSIONS: A monthly dose of 50 000 IU of vitamin D3 alone for 12 months does not affect the size or ability to contract trunk muscles of independent community-dwelling older adults with symptomatic knee osteoarthritis and low serum 25(OH) D levels regardless of body mass index status or degree of vitamin D deficiency. An effect of vitamin D supplementation on other aspects of trunk muscle function such as strength, power, or physical function cannot be ruled out.

A protocol for a multicentre, randomised, double-blind, placebo-controlled trial to compare the effect of annual infusions of zoledronic acid to placebo on knee structural change and knee pain over 24 months in knee osteoarthritis patients - ZAP2.

BACKGROUND: Bisphosphonates are a class of drugs that slow bone loss and are a promising candidate to treat knee osteoarthritis (OA) patients. In a pilot study, we demonstrated that zoledronic acid reduced knee pain and size of subchondral bone marrow lesions (BMLs) over 6 months in knee OA patients with significant knee pain and BMLs. A longer, larger study is required to assess whether decreases in BML size will translate to reductions in cartilage loss over time. We are currently conducting a multicentre, randomised, double-blind, placebo-controlled trial over 24 months that aims to compare the effect of annual infusions of zoledronic acid to placebo on knee structural change (assessed using magnetic resonance imaging (MRI)) and knee pain in knee OA patients. METHODS: Two hundred sixty-four patients with clinical knee OA, significant knee pain and subchondral BMLs present on MRI will be recruited in Hobart, Melbourne, Sydney and Adelaide. They will be randomly allocated to the two arms of the study, receiving an annual identical intravenous infusion of either 100 mL of fluid containing zoledronic acid (5 mg/100 mL) or placebo (0.9% NaCl 100 mL), at baseline and 1 year later. MRI of the study knee will be performed at screening, month 6 and 24. Knee structure, symptoms and function will be assessed using validated methods. The primary outcome is absolute change in tibiofemoral cartilage volume (mm3) over 24 months. Secondary outcomes include improvement in knee pain over 3, 6, 12, 18, and 24 months and reductions in BML size over 6 and 24 months. The primary analyses will be intention-to-treat analyses of primary and secondary outcomes. Per protocol analyses will be performed as the secondary analyses. DISCUSSION: This study will provide high-quality evidence to assess whether zoledronic acid has a novel disease modifying effect in OA by slowing cartilage loss and reducing pain. If zoledronic acid proves effective, it suggests great potential for cost savings through a delay or reduced need for joint replacement surgery, and potential for great improvements in quality of life for OA suffers. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12613000039785 , registered on 14 January 2013.

Female Reproductive and Hormonal Factors and Incidence of Primary Total Knee Arthroplasty Due to Osteoarthritis.

OBJECTIVE: To examine the associations of female reproductive and hormonal factors with incidence of total knee arthroplasty (TKA) for osteoarthritis (OA), and to determine whether the associations differ according to overweight/obesity status. METHODS: This study included 22,289 women in the Melbourne Collaborative Cohort Study. Data on age at menarche, pregnancy, parity, years of menstruation, oral contraceptive (OC) use, menopausal status, and hormone replacement therapy (HRT) were collected in 1990-1994. Incidence of TKA during 2001-2013 was determined by linking cohort records to the Australian Orthopaedic Association National Joint Replacement Registry. All analyses were adjusted for age, body mass index (BMI) at midlife, change in BMI (from early reproductive age to midlife), country of birth, physical activity, smoking, and education level. RESULTS: Over the course of 12.7 years, 1,208 TKAs for OA were identified. Ever being pregnant was associated with increased risk of TKA (hazard ratio [HR] 1.32 [95% confidence interval (95% CI) 1.06-1.63]). Parity was positively associated with risk of TKA (P for trend = 0.003). OC users had increased risk of TKA compared with non-users (for OC use of <5 years, HR 1.25 [95% CI 1.08-1.45]; for OC use of ≥5 years, HR 1.17 [95% CI 1.00-1.37]). A 1-year increase in menstruation was associated with a 1% decrease in risk of TKA (HR 0.99 [95% CI 0.97-0.99]). These associations remained significant only in women of normal weight at early reproductive age. Current HRT users had increased risk of TKA compared with non-users (HR 1.37 [95% CI 1.14-1.64]); the association was significant only in non-obese women at midlife. CONCLUSION: Reproductive and hormonal factors were associated with risk of knee OA. These associations remained significant in women of normal weight at early reproductive age and in non-obese women at midlife. Further work is needed to understand the complex effect of these factors on knee OA.

Bone matrix microdamage and vascular changes characterize bone marrow lesions in the subchondral bone of knee osteoarthritis.

INTRODUCTION: Bone marrow lesions (BMLs) in the subchondral bone in osteoarthritis (OA) are suggested to be multifactorial, although the pathogenic mechanisms are unknown. Bone metabolism and cardiovascular risk factors associate with BML in epidemiologic studies. However, there are no studies at the tissue level investigating the relationship between these processes and BML. The aim of this study was to investigate the relationship between BMLs in the tibial plateau (TP) of knee OA and bone matrix microdamage, osteocyte density and vascular changes. METHODS: TP were obtained from 73 patients at total knee replacement surgery and BMLs were identified ex vivo in TP tissue using MRI. Comparator 'No BML' tissue was from matched anatomical sites to the BMLs. Quantitative assessment was made of subchondral bone microdamage, bone resorption indices, osteocyte cellularity, and vascular features. RESULTS: Several key parameters were different between BML and No BML tissue. These included increased microcrack burden (p = .01, p = .0001), which associated positively with bone resorption and negatively with cartilage volume, and greater osteocyte numerical density (p = .02, p = .01), in the subchondral bone plate and subchondral trabeculae, respectively. The marrow tissue within BML zones contained increased arteriolar density (p = .04, p = .0006), and altered vascular characteristics, in particular increased wall thickness (p = .007) and wall:lumen ratio (wall thickness over internal lumen area) (p = .001), compared with No BML bone. CONCLUSIONS: Increased bone matrix microdamage and altered vasculature in the subchondral bone of BMLs is consistent with overloading and vascular contributions to the formation of these lesions. Given the important role of BMLs in knee OA, these contributing factors offer potential targets for the treatment and prevention of knee OA.

Association between Dairy Product Consumption and Incidence of Total Hip Arthroplasty for Osteoarthritis.

OBJECTIVE: The aim of this prospective cohort study was to determine whether dairy product consumption was associated with the incidence of total hip arthroplasty for osteoarthritis (OA). METHODS: There were 38,924 participants from the Melbourne Collaborative Cohort Study who had dairy product consumption recorded in 1990-1994. The incidence of total hip arthroplasty for OA during 2001-2013 was determined by linking cohort records to the Australian Orthopaedic Association National Joint Replacement Registry. RESULTS: Over an average of 11.8 years of followup, 1505 total hip arthroplasties for OA were identified (524 in men, 981 in women). In men, a 1 SD increase in dairy product consumption was associated with a 21% increased incidence of total hip arthroplasty for OA (HR 1.21, 95% CI 1.10-1.33), with a dose-response relationship observed for quartiles of dairy product consumption (p for trend = 0.001). These results were independent of age, body mass index, country of birth, education, smoking status, vigorous physical activity, calcium supplementation, energy consumption, circulating 25-hydroxy vitamin D, hypertension, and diabetes. No significant association was observed for women (HR 1.02, 95% CI 0.95-1.09). CONCLUSION: Increasing dairy product consumption was associated with an increased risk of total hip arthroplasty for men with OA, with no significant association observed for women. Understanding the mechanisms may help identify strategies to prevent hip OA, particularly for men.