Differences between race and sex in measures of hip morphology: a population-based comparative study.

OBJECTIVE: This paper aims to (i) identify differences in measures of hip morphology between four racial groups using anteroposterior (AP) hip x-rays, and (ii) examine whether these differences vary by sex. METHODS: 912 hip x-rays (456 individuals) from four racial groups (European Caucasians, American Caucasians, African Americans and Chinese) were obtained. Males and females (45-75 years) with no radiographic hip OA (Kellgren and Lawrence < Grade 2 or Croft < Grade 1) were included. Eleven features of hip joint morphology were analysed. Linear regression with generalised estimating equations (GEE) was used to determine race and sex differences in hip morphology. Post-hoc Bonferroni procedure was used to adjust for multiple comparisons. RESULTS: The final analysis included 875 hips. Chinese hips showed significant differences for the majority of measures to other racial groups. Chinese were characterised by more shallow and narrow acetabular sockets, reduced femoral head coverage, smaller femoral head diameter, and a lesser angle of alignment between the femoral neck and shaft. Variation was found between other racial groups, but with few statistically significant differences. The average of lateral centre edge angle, minimum neck width and neck length differed between race and sex (p-value for interaction < 0.05). CONCLUSIONS: Significant differences were found in measures of morphology between Chinese hips compared to African Americans or Caucasian groups; these may explain variation in hip OA prevalence rates between these groups and the lower rate of hip OA in Chinese. Sex differences were also identified, which may further explain male-female prevalence differences for OA.

Harmonising measures of knee and hip osteoarthritis in population-based cohort studies: an international study.

OBJECTIVE: Population-based osteoarthritis (OA) cohorts provide vital data on risk factors and outcomes of OA, however the methods to define OA vary between cohorts. We aimed to provide recommendations for combining knee and hip OA data in extant and future population cohort studies, in order to facilitate informative individual participant level analyses. METHOD: International OA experts met to make recommendations on: 1) defining OA by X-ray and/or pain; 2) compare The National Health and Nutrition Examination Survey (NHANES)-type OA pain questions; 3) the comparability of the Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) scale to NHANES-type OA pain questions; 4) the best radiographic scoring method; 5) the usefulness of other OA outcome measures. Key issues were explored using new analyses in two population-based OA cohorts (Multicenter Osteoarthritis Study; MOST and Osteoarthritis Initiative OAI). RESULTS: OA should be defined by both symptoms and radiographs, with symptoms alone as a secondary definition. Kellgren and Lawrence (K/L) grade ≥2 should be used to define radiographic OA (ROA). The variable wording of pain questions can result in varying prevalence between 41.0% and 75.4%, however questions where the time anchor is similar have high sensitivity and specificity (91.2% and 89.9% respectively). A threshold of 3 on a 0-20 scale (95% CI 2.1, 3.9) in the WOMAC pain subscale demonstrated equivalence with the preferred NHANES-type question. CONCLUSION: This research provides recommendations, based on expert agreement, for harmonising and combining OA data in existing and future population-based cohorts.

Physical activity and osteoarthritis: a consensus study to harmonise self-reporting methods of physical activity across international cohorts.

Physical activity (PA) is increasingly recognised as an important factor within studies of osteoarthritis (OA). However, subjective methods used to assess PA are highly variable and have not been developed for use within studies of OA, which creates difficulties when comparing and interpreting PA data in OA research. The aim of this study was, therefore, to gain expert agreement on the appropriate methods to harmonise PA data among existing population cohorts to enable the investigation of the association of PA and OA. The definition of PA in an OA context and methods of harmonization were established via an international expert consensus meeting and modified Delphi exercise using a geographically diverse committee selected on the basis of individual expertise in physical activity, exercise medicine, and OA. Agreement was met for all aims of study: (1) The use of Metabolic Equivalent of Task (MET) minutes per week (MET-min/week) as a method for harmonising PA variables among cohorts; (2) The determination of methods for treating missing components of MET-min/week calculation; a value will be produced from comparable activities within a representative cohort; (3) Exclusion of the domain of occupation from total MET-min/week; (4) The need for a specific measure of joint loading of an activity in addition to intensity and time, in studies of diseases, such as OA. This study has developed a systematic method to classify and harmonise PA in existing OA cohorts. It also provides minimum requirements for future studies intending to include subjective PA measures.

Painful knee but not hand osteoarthritis is an independent predictor of mortality over 23†years follow-up of a population-based cohort of middle-aged women.

UNLABELLED: To assess whether joint pain or radiographic osteoarthritis (ROA) of the knee and hand is associated with all-cause and disease-specific mortality in middle-aged women. METHODS: Four subgroups from the prospective community-based Chingford Cohort Study were identified based on presence/absence of pain and ROA at baseline: (Pain-/ROA-; Pain+/ROA-; Pain-/ROA+; Pain+/ROA+). Pain was defined as side-specific pain in the preceding month, while side-specific ROA was defined as Kellgren-Lawrence grade ≥2. All-cause, cardiovascular disease (CVD) and cancer-related mortality over the 23-year follow-up was based on information collected by the Office for National Statistics. Associations between subgroups and all-cause/cause-specific mortality were assessed using Cox regression, adjusting for age, body mass index, typical cardiovascular risk factors, occupation, past physical activity, existing CVD disease, glucose levels and medication use. RESULTS: 821 and 808 women were included for knee and hand analyses, respectively. Compared with the knee Pain-/ROA- group, the Pain+/ROA- group had an increased risk of CVD-specific mortality (HR 2.93 (95% CI 1.47 to 5.85)), while the knee Pain+/ROA+ group had an increased HR of 1.97 (95% CI 1.23 to 3.17) for all-cause and 3.57 (95% CI 1.53 to 8.34) for CVD-specific mortality. We found no association between hand OA and mortality. CONCLUSION: We found a significantly increased risk of all-cause and CVD-specific mortality in women experiencing knee pain with or without ROA but not ROA alone. No relationship was found between hand OA and mortality risk. This suggests that knee pain, more than structural changes of OA is the main driver of excess mortality in patients with OA.

A comparison of radiographic anatomic axis knee alignment measurements and cross-sectional associations with knee osteoarthritis.

OBJECTIVE: Malalignment is associated with knee osteoarthritis (KOA), however, the optimal anatomic axis (AA) knee alignment measurement on a standard limb radiograph (SLR) is unknown. This study compares one-point (1P) and two-point (2P) AA methods using three knee joint centre locations and examines cross-sectional associations with symptomatic radiographic knee osteoarthritis (SRKOA), radiographic knee osteoarthritis (RKOA) and knee pain. METHODS: AA alignment was measured six different ways using the KneeMorf software on 1058 SLRs from 584 women in the Chingford Study. Cross-sectional associations with principal outcome SRKOA combined with greatest reproducibility determined the optimal 1P and 2P AA method. Appropriate varus/neutral/valgus alignment categories were established using logistic regression with generalised estimating equation models fitted with restricted cubic spline function. RESULTS: The tibial plateau centre displayed greatest reproducibility and associations with SRKOA. As mean 1P and 2P values differed by >2°, new alignment categories were generated for 1P: varus <178°, neutral 178-182°, valgus >182° and for 2P methods: varus <180°, neutral 180-185°, valgus >185°. Varus vs neutral alignment was associated with a near 2-fold increase in SRKOA and RKOA, and valgus vs neutral for RKOA using 2P method. Nonsignificant associations were seen for 1P method for SRKOA, RKOA and knee pain. CONCLUSIONS: AA alignment was associated with SRKOA and the tibial plateau centre had the strongest association. Differences in AA alignment when 1P vs 2P methods were compared indicated bespoke alignment categories were necessary. Further replication and validation with mechanical axis alignment comparison is required.

Measures of hip morphology are related to development of worsening radiographic hip osteoarthritis over 6 to 13 year follow-up: the Johnston County Osteoarthritis Project.

OBJECTIVES: We sought to describe the effect of alterations in hip morphology with respect to worsening hip OA in a community-based sample including African American (AA) and white men and women. METHODS: This nested case-control study defined case hips as Kellgren Lawrence grade (KLG) <3 on baseline supine pelvis radiographs and KLG ≥3 or THR for OA at the 1st or 2nd follow-up visit (mean 6 and 13 years, respectively); control hips had KLG <3 at both visits, with gender/race distribution similar to cases. Hip morphology was assessed using HipMorf software (Oxford, UK). Descriptive means and standard errors were obtained from generalized estimating equation (GEE) models. Sex-stratified GEE regression models (accounting for within-person correlation), adjusted for age, race, BMI, and side were then employed. RESULTS: A total of 120 individuals (239 hips; 71 case/168 control) were included (25% male, 26% AA, mean age 62 years, BMI 30 kg/m(2)). Case hips tended to have greater baseline AP alpha angles, smaller minimum joint space width (mJSW) and more frequent triangular index signs. Adjusted results among men revealed that higher AP alpha angle, Gosvig ratio, and acetabular index were positively associated with case hips; coxa profunda was negatively associated. Among women, greater AP alpha angle, smaller mJSW, protrusio acetabuli, and triangular index sign were associated with case hips. CONCLUSIONS: We confirmed an increased risk of worsening hip OA due to baseline features of cam deformity among men and women, as well as protrusio acetabuli among women, and provide the first estimates of these measures in AAs.

Osteoarthritis year 2013 in review: clinical.

Some major themes over the past year in clinical research of osteoarthritis (OA) include obesity, muscle strength, pain mechanisms, novel disease modifying drugs, and risk factors for poor outcomes of joint replacement surgery. A systematic literature search was performed using PubMed from January 2012 to December 2012. The articles selected for this review represent topics the authors thought best highlight recent clinical OA research.

The natural history of radiographic knee osteoarthritis: a fourteen-year population-based cohort study.

OBJECTIVE: To establish the natural history of radiographic knee osteoarthritis (OA) over 14 years in a community-based cohort. METHODS: We examined women from the Chingford Women's Study, a community-based cohort followed up for more than 14 years. We selected women for whom bilateral radiographs of the knees (with the legs in full extension) were obtained at approximately 5-year intervals. Radiographs were scored for OA in a blinded manner, using Kellgren/Lawrence (K/L) grades. Descriptive statistics and odds ratios (ORs) were used to compare the incidence, worsening, and progression of radiographic knee OA. RESULTS: A complete radiography series was available for 561 of the original 1,003 subjects enrolled in the study. The median age of these subjects at baseline was 53 years (interquartile range 48-58 years). At baseline, 13.7% of the subjects had radiographic knee OA (K/L grade≥2) in at least one knee, and the prevalence increased to 47.8% by year 15. The annual cumulative incidence of radiographic knee OA was 2.3% between baseline and year 15. The annual rates of disease progression and worsening between baseline and year 15 were 2.8% and 3.0%, respectively. Subjects with a K/L grade of 1 at baseline were more likely to experience worsening by year 15 compared with subjects with a baseline grade of 0 (OR 4.5, 95% confidence interval 2.7-7.4). CONCLUSION: This is the longest natural history study of radiographic knee OA to date. The results showed relatively low rates for the incidence and progression of radiographic knee OA; more than half of all subjects had no radiographic evidence of knee OA over a 15-year period of time. Subjects with a baseline K/L grade of 1 were more likely than subjects with other baseline K/L grades to experience worsening of knee OA.

Prevalence of reported knee pain over twelve years in a community-based cohort.

OBJECTIVE: To describe the temporal patterns of knee pain in a community-based cohort over 12 years. METHODS: Data on self-reported knee pain at 4 time points over 12 years were analyzed in participants from the Chingford Women's Study of osteoarthritis (OA) and osteoporosis. Pain status was defined as any pain in the preceding month and pain on most days in the preceding month. This status was used to classify participants according to pain patterns of asymptomatic, persistent, incident, or intermittent pain. Multinomial logistic regression was used to identify baseline predictors for each pain pattern. RESULTS: Among the 489 women with complete followup data, the median age at baseline was 52 years (interquartile range [IQR] 48-58 years), the median body mass index (BMI) was 24.39 kg/m(2) (IQR 22.46-27.20), and 11.7% of the women had a Kellgren/Lawrence radiographic OA severity grade of ≥2 in at least one knee. Among subjects reporting any pain in the preceding month versus those reporting pain on most days in the preceding month, 9% versus 2% had persistent pain, 24% versus 16% had incident pain, and 29% versus 18% had intermittent pain. A higher BMI was predictive of persistent pain (odds ratio [OR] 1.14, 95% confidence interval [95% CI] 1.04-1.25) and incident pain (OR 1.10, 95% CI 1.02-1.18). The presence of radiographic knee OA was predictive of persistent pain (OR 3.70, 95% CI 1.34-10.28; P = 0.012), and reported knee injury was predictive of both persistent pain (OR 4.13, 95% CI 1.34-12.66; P = 0.013) and intermittent pain (OR 4.25, 95% CI 1.81-9.98; P = 0.001). CONCLUSION: Significant variability in the temporal fluctuation of self-reported knee pain was seen in this community-based prospective study over a period of 12 years, with few women consistently reporting knee pain at each time point. Distinct baseline predictors for each pain pattern were identified and may explain the observed heterogeneity of self-reported knee pain when pain status is measured at only one time point.