Laura L. Laslett

The global burden of hip and knee osteoarthritis: estimates from the Global Burden of Disease 2010 study

Objective To estimate the global burden of hip and knee osteoarthritis (OA) as part of the Global Burden of Disease 2010 study and to explore how the burden of hip and knee OA compares with other conditions. Methods Systematic reviews were conducted to source age-specific and sex-specific epidemiological data for hip and knee OA prevalence, incidence and mortality risk. The prevalence and incidence of symptomatic, radiographic and self-reported hip or knee OA were included. Three levels of severity were defined to derive disability weights (DWs) and severity distribution (proportion with mild, moderate and severe OA). The prevalence by country and region was multiplied by the severity distribution and the appropriate disability weight to calculate years of life lived with disability (YLDs). As there are no deaths directly attributed to OA, YLDs equate disability-adjusted life years (DALYs). Results Globally, of the 291 conditions, hip and knee OA was ranked as the 11th highest contributor to global disability and 38th highest in DALYs. The global age-standardised prevalence of knee OA was 3.8% (95% uncertainty interval (UI) 3.6% to 4.1%) and hip OA was 0.85% (95% UI 0.74% to 1.02%), with no discernible change from 1990 to 2010. Prevalence was higher in females than males. YLDs for hip and knee OA increased from 10.5 million in 1990 (0.42% of total DALYs) to 17.1 million in 2010 (0.69% of total DALYs). Conclusions Hip and knee OA is one of the leading causes of global disability. Methodological issues within this study make it highly likely that the real burden of OA has been underestimated. With the aging and increasing obesity of the worlds population, health professions need to prepare for a large increase in the demand for health services to treat hip and knee OA.

Zoledronic acid reduces knee pain and bone marrow lesions over 1 year: a randomised controlled trial

Objectives To compare the effect of a single infusion of zoledronic acid (ZA) with placebo on knee pain and bone marrow lesions (BMLs). Methods Adults aged 50–80 years (n=59) with clinical knee osteoarthritis and knee BMLs were randomised to receive either ZA (5 mg/100 ml) or placebo. BMLs were determined using proton density-weighted fat saturation MR images at baseline, 6 and 12 months. Pain and function were measured using a visual analogue scale (VAS) and the knee injury and osteoarthritis outcome score (KOOS) scale. Results At baseline, mean VAS score was 54 mm and mean total BML area was 468 mm2. VAS pain scores were significantly reduced in the ZA group compared with placebo after 6 months (−14.5 mm, 95% CI −28.1 to −0.9) but not after 3 or 12 months. Changes on the KOOS scales were not significant at any time point. Reduction in total BML area was greater in the ZA group compared with placebo after 6 months (−175.7 mm2, 95% CI −327.2 to −24.3) with a trend after 12 months (−146.5 mm2, 95% CI −307.5 to +14.5). A greater proportion of those in the ZA group achieved a clinically significant reduction in BML size at 6 months (39% vs 18%, p=0.044). Toxicity was as expected apart from a high rate of acute phase reactions in treatment and placebo arms. Conclusions ZA reduces knee pain and areal BML size and increases the proportion improving over 6 months. Treatment of osteoarthritis may benefit from a lesion specific therapeutic approach. Clinical trial registration number ACTRN 12609000399291.

The Ile585Val TRPV1 variant is involved in risk of painful knee osteoarthritis

Objective To assess if a coding variant in the gene encoding transient receptor potential cation channel, subfamily V, member 1 (TRPV1) is associated with genetic risk of painful knee osteoarthritis (OA). Methods The Ile585Val TRPV1 variant encoded by rs8065080 was genotyped in 3270 cases of symptomatic knee OA, 1098 cases of asymptomatic knee OA and 3852 controls from seven cohorts from the UK, the USA and Australia. The genetic association between the low-pain genotype Ile–Ile and risk of symptomatic and asymptomatic knee OA was assessed. Results The TRPV1 585 Ile–Ile genotype, reported to be associated with lower thermal pain sensitivity, was associated with a lower risk of symptomatic knee OA in a comparison of symptomatic cases with healthy controls, with an odds ratio (OR) of 0.75 (95% CI 0.64 to 0.88; p=0.00039 by meta-analysis) after adjustment for age, sex and body mass index. No difference was seen between asymptomatic OA cases and controls (OR=1.02, 95% CI 0.82 to 1.27 p=0.86) but the Ile–Ile genotype was associated with lower risk of symptomatic versus asymptomatic knee OA adjusting for covariates and radiographic severity (OR=0.73, 95% CI 0.57 to 0.94 p=0.0136). TRPV1 expression in articular cartilage was increased by inflammatory cytokines (tumour necrosis factor α and interleukin 1). However, there were no differences in TRPV1 expression in healthy and arthritic synovial tissue. Conclusions A genotype involved in lower peripheral pain sensitivity is significantly associated with a decreased risk of painful knee OA. This indicates a role for the pro-nociceptive gene TRPV1 in genetic susceptibility to symptomatic knee OA, which may also be influenced by a role for this molecule in cartilage function.

Moderate vitamin D deficiency is associated with changes in knee and hip pain in older adults: a 5-year longitudinal study

Background Vitamin D is important for bone, cartilage and muscle function but there are few studies on its association with joint pain. Objective To investigate whether serum vitamin D predicts change in knee and hip pain in older adults. Methods Longitudinal population-based cohort study of randomly selected older adults (n=769) aged 50–80 years (mean 62 years); 50% were male. Serum 25-hydroxyvitamin D (25-OHD) was assessed at baseline by radioimmunoassay, and pain at baseline, 2.6 and/or 5 years using the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) questionnaire. We used linear regression with adjustment for age, sex, body mass index and season, then further adjusted for potential structural mechanisms (radiographic osteoarthritis, bone marrow lesions, chondral defects and muscle strength). Results Mean total knee WOMAC score was 3.2 (range 0–39). 4.2% of participants had moderate vitamin D deficiency at baseline (25-OHD 12.5–25 nmol/l). 25-OHD <25 nmol/l predicted change in knee pain (using total WOMAC score) over 5 years (β=2.41, p=0.002) with a similar effect size for hip pain over 2.4 years (β=2.20, p=0.083). Results were consistent within pain subscales, and the association was independent of demographic, anthropometric and structural covariates. No association was present when 25-OHD was analysed as a continuous measure. Conclusions Moderate vitamin D deficiency independently predicts incident, or worsening of, knee pain over 5 years and, possibly, hip pain over 2.4 years. Therefore correcting moderate vitamin deficiency may attenuate worsening of knee or hip pain in elderly people but giving supplements to those with a higher 25-OHD level is unlikely to be effective.

Effect of bisphosphonate use in patients with symptomatic and radiographic knee osteoarthritis: data from the Osteoarthritis Initiative

Objectives Bisphosphonates have some reported beneficial effects in treating osteoarthritis (OA). This study examined the effects of bisphosphonate use on symptoms and structural progression of knee OA in participants from the NIH Osteoarthritis Initiative cohort. Methods People with typical OA trial entry criteria (KL2/3, minimum joint space width 2.5–5.0 mm and pain ≥4 on a numeric rating scale) were classified as bisphosphonate users (≥3 of the 5 years; n=55) or non-users (no use in the preceding 5 years or during follow-up; n=268). Annual data over 4 years were analysed using linear mixed modelling and generalised estimating equations. Results Bisphosphonate compliance was 85% at year 1, reducing to 76% by year 4. Numeric rating scale pain scores were significantly reduced among bisphosphonate users at years 2 and 3 (year 3, −0.9 vs −2.2, p=0.004), though not year 4, after adjustment for baseline pain and analgesic use. Differences in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and disability scores did not reach statistical significance at any time point. There was a trend to less joint space narrowing in bisphosphonate users over time (year 4, 0.51 vs 0.29 mm; p=0.06). Conclusions Significant reduction in numeric rating scale pain was observed in the first 3 years with bisphosphonate use; diminution of effects by year 4 may reflect reduced compliance. Differences in results obtained using numeric rating scale and WOMAC may reflect different constructs measured by these tools. The beneficial trend on structural progression should be considered in terms of the sample size.

Hand syndromes associated with diabetes: impairments and obesity predict disability.

Objective. We determined patterns of disability in diabetic hand conditions and identified factors that contributed to functional limitations. Methods. Hand assessments were performed on 60 adults with DM1 or DM2 and carpal tunnel syndrome, trigger finger, Dupuytren’s disease, or the syndrome of limited joint mobility. The examination included measurement of grip strength, light touch perception, and dexterity, as well as self-reported function using the Disabilities of the Arm, Shoulder and Hand (DASH) instrument and the Medical Outcomes Study Short Form-36 questionnaire. Associations with hand disability were analyzed using correlation and regression. Results. The most frequent presentation was carpal tunnel syndrome (45%) but it was common for patients to present with clinical features associated with more than one hand syndrome (47%). Overall, women had greater difficulties, with significantly higher DASH scores than men [mean 30.3 (95% CI 23.2, 37.5) vs 18.0 (95% CI 12.1, 23.9), respectively; p = 0.01]. Grip strength, dexterity, and obesity were associated with hand disability (p < 0.05). Conclusion. In adults with hand syndromes associated with diabetes, disability was related to impaired muscle function and carpal tunnel syndrome. Obesity and overall physical functioning influenced hand disability, particularly in women.

A prospective study of the impact of musculoskeletal pain and radiographic osteoarthritis on health related quality of life in community dwelling older people.

BackgroundPain and radiographic changes are common in persons with osteoarthritis, but their relative contributions to quality of life are unknown.MethodsProspective cohort study of 1098 men and women aged 50–80 years, randomly selected from the electoral roll. Participants were interviewed at baseline and approximately 2.6 and five years later. Participants self-reported prior diagnosis of arthritis and presence of joint pain. Joint space narrowing (JSN) and osteophytes at the hip and knee were assessed by X-ray. Quality of life (QoL) was assessed using the Assessment of QoL (AQoL) instrument. Data was analysed using linear regression and mixed modelling.ResultsThe median AQoL score at baseline was 7.0, indicating very good QoL. Prevalence of pain ranged from 38-62%. Over five years of observation, pain in the neck, shoulders, back, hips, hands, knees and feet were all independently and negatively associated with QoL, in a dose–response relationship. Diagnosed osteoarthritis at all sites was associated with poorer QoL but after adjustment for pain, this only remained significant at the back. Radiographic OA was not associated with QoL. While AQoL scores declined over five years, there was no evidence of an interaction between pain and time.ConclusionsPain is common in older adults, is stable over time, and the strongest musculoskeletal correlate of QoL. It also mediates the association between diagnosed OA and QoL. Since the same factors were associated with quality of life over time as at baseline, this suggests that quality of life tracks over a five year period.

Association Between Infrapatellar Fat Pad Volume and Knee Structural Changes in Patients with Knee Osteoarthritis

Objective. The function of the infrapatellar fat pad (IPFP) in knee osteoarthritis (OA) remains uncertain. This study aimed to examine cross-sectional associations between IPFP volume and knee structures in patients with knee OA. Methods. The study included 174 patients with clinical knee OA (mean age, 55.5 yrs). Fat-suppressed 3-D T1-weighted spoiled gradient recall magnetic resonance imaging (MRI) was used to measure the IPFP and cartilage volume. T2-weighted fast spin echo MRI was used to assess cartilage defects and bone marrow lesions (BML). Radiographic knee osteophytes and joint space narrowing (JSN) were assessed using the Osteoarthritis Research Society International atlas. Results. After adjustment for potential confounders, greater IPFP volume was associated with greater tibial and patellar cartilage volume (all p < 0.05), and fewer cartilage defects at all sites (OR 0.88–0.91, all p < 0.05). IPFP volume was associated with presence of BML at lateral tibial and medial femoral sites (OR 0.88–0.91, all p < 0.05) and osteophytes at lateral tibiofemoral compartment (OR 0.88, p < 0.05). IPFP volume was not significantly associated with JSN. Conclusion. Greater IPFP volume was associated with greater knee cartilage volume and fewer structural abnormalities, suggesting a protective role of IPFP size in knee OA.

Osteoporosis education improves osteoporosis knowledge and dietary calcium: comparison of a 4 week and a one-session education course

Background:  Education is ideal for osteoporosis because many risk factors are modifiable. However, the efficacy of shortened education courses compared to a standard 4 week course for improving osteoporosis knowledge and healthy behaviours is not known. This study aimed to assess whether education changed knowledge and healthy behaviours over 3 months of follow‐up; and whether changes in these outcomes were different between participants receiving the different education courses.

Randomized controlled trial of alendronate in airways disease and low bone mineral density

Background:Patients with airways disease have been demonstrated to be at risk of osteoporosis, and this is likely to be multifactorial. Our aim was to identify patients with low bone mineral density (BMD) using a screening program, and then evaluate the benefit of daily alendronate. Method:Subjects with hip or lumbar spine baseline T-scores <-2.5, or Z-score <-1.0 commenced on alendronate/calcium (10 mg/600 mg day) or placebo/calcium, in a double blind randomized controlled trial. BMD by dual emission X-ray absorptiometry (lumbar vertebrae 2-4, neck of femur, total femur) was repeated after 12 months, with adverse events recorded. Results: 145 subjects (74 male, 71 female, mean age 67, median FEV, 1.0 litres = 43% of predicted) were enrolled; 66 alendronate/calcium, 79 placebo/calcium with 24 and 26 withdrawals, respectively. Per protocol but not intention to treat analysis of covariance demonstrated statistically significant improvements in T and Z scores for lumbar spine bone mineral density (P = 0.035, P = 0.040), with no improvement demonstrated at the hip. Conclusions:Improvement in bone mineral density has been demonstrated at the lumbar spine, but not hip, by per protocol analysis, with daily alendronate, at 12 months.