Prevalence of intra-articular mineralization on knee computed tomography: the multicenter osteoarthritis study.

OBJECTIVE: The aim of this work was to report the prevalence of computed tomography (CT)-detected intra-articular mineralization. DESIGN: We included participants from the Multicenter Osteoarthritis (MOST) Study. At the 12th year visit of the MOST study, bilateral knee CTs were first obtained. All participants also had posteroanterior and lateral radiographs of bilateral knees and completed standard questionnaires. Knee radiographs were assessed for Kellgren & Lawrence grade (KLG) and radiographic evidence of intra-articular mineralization. CT images were scored using the Boston University Calcium Knee Score (BUCKS) for cartilage, menisci, ligaments, capsule, and vasculature. Prevalence of intra-articular mineralization was computed for the total sample, and stratified by age, sex, race, Body Mass Index (BMI), presence of frequent knee pain, and KLG. We also determined distribution of mineralization in the cartilage and meniscus, and co-localization. RESULTS: 4140 bilateral knees from 2070 participants were included (56.7% female, mean age 61.1 years, mean BMI: 28.8 kg/m2). On radiographs 240 knees (5.8%) had intraarticular mineralization, while CT-detected mineralization was present in 9.8% of knees. Prevalence of hyaline articular and meniscus mineralization increased with age and KL grade, and was similar by sex, BMI categories, and comparable in subjects with and without frequent knee pain. Mineralization tended to be ubiquitous in the joint, most commonly involving all three (medial/lateral tibiofemoral and patellofemoral) compartments (3.1%), while the patellofemoral compartment was the most involved compartment in isolation (1.4%). CONCLUSIONS: CT of the knee provides greater visualization of intra-articular mineralization than radiographs and allows better localization of the crystal deposition within the joint. Further studies should focus on the co-localization of intra-articular crystal deposition and corresponding magnetic resonance imaging (MRI)-features of knee osteoarthritis (OA).

Evidence that meniscus damage may be a component of osteoarthritis: the Framingham study.

OBJECTIVES: The etiology of degenerative meniscus tear is unclear but could be related to a generalized osteoarthritic disease process. We studied whether radiographic hand osteoarthritis (OA) is associated with meniscus damage. METHODS: We examined 974 persons aged 50-90 years drawn via census tract data and random-digit dialing from Framingham, Massachusetts, United States. One reader assessed bilateral hand radiographs (30 joints) and another read frontal knee radiographs, all according to the Kellgren-Lawrence (KL) scale. A third reader assessed right knee 1.5-T magnetic resonance imaging (MRI) scans for meniscus damage. We calculated the prevalence of medial and/or lateral meniscus damage in those with one to two and three or more finger joints with radiographic OA (KL grade ≥2) compared to those without radiographic hand OA with adjustment for age, sex, and body mass index. We also evaluated the above association in persons without evidence of radiographic OA (KL grade 0) in their knee (n = 748). RESULTS: The prevalence of meniscus damage in the knee of subjects with no, one to two, and three or more finger joints with OA was 24.9%, 31.7%, and 47.2%, respectively. The adjusted prevalence ratio (PR) of having meniscus damage was significantly increased in those who had three or more finger joints with OA (1.40 [95% confidence interval (CI) 1.11-1.77]). The estimate remained similar in persons without evidence of radiographic OA in their knee (PR, 1.42 [95% CI 1.03-1.97]). The association was more robust for medial meniscus damage. CONCLUSION: Results suggest a common non-age related etiologic pathway for both radiographic hand OA and meniscus damage.

Pre-radiographic osteoarthritic changes are highly prevalent in the medial patella and medial posterior femur in older persons: Framingham OA study.

OBJECTIVE: To determine which subregions of the knee joint have a high prevalence of pre-radiographic osteoarthritic changes, i.e., cartilage damage and osteophytes that can only be detected by magnetic resonance imaging (MRI), in radiographically normal knees. METHODS: Institutional Review Board approval and written informed consent from all participants was obtained. Data was collected from a community cohort in Framingham, MA, involving people aged 50-79. Participants underwent weight-bearing posteroanterior and lateral knee radiography with the fixed-flexion protocol, and 1.5 T MRI. Knees without radiographic osteoarthritis (Kellgren Lawrence grade 0 for the tibiofemoral joint and absence of any osteophytes or joint space narrowing in the patellofemoral joint) were included. The knee joint was divided into 14 subregions for cartilage and 16 subregions for osteophytes, and prevalence and severity of cartilage damage (grade 0-6) and osteophytes (grade 0-7) were semiquantitatively assessed using the Whole Organ Magnetic Resonance Imaging Score (WORMS). RESULTS: The mean age of 696 participants was 62.3 ± 8.4 years, and the mean body mass index was 27.9 ± 5.1 kg/m2. Women comprised 55.2% of the study sample (384/696). Prevalence of cartilage damage (grade ≥2) was 47.7% (332/696) in the medial patellar and 29.9% (208/696) in patellar lateral (PL) subregions, and 24.0% (167/696) in femoral medial anterior (FMA) and 26.5% (184/696) in femoral medial central (FMC) subregions. Prevalence of osteophytes (grade ≥2) was highest at 60.8% (423/696) in the medial femoral posterior subregion, followed by 34.0% (237/696) in PL and 24.6% (171/696) in patellar medial (PM) subregions. For all other subregions, prevalence of these lesions was lower than the aforementioned percentages. CONCLUSION: MRI-detected cartilage damage and osteophytes are highly prevalent in the medial patellofemoral and medial posterior tibiofemoral joints in radiographically normal knees in persons aged 50-79.

Physical activity, alignment and knee osteoarthritis: data from MOST and the OAI.

OBJECTIVE: To determine the effect of physical activity on knee osteoarthritis (OA) development in persons without knee injury and according to knee alignment. DESIGN: We combined data from Multicenter Osteoarthritis (MOST) and Osteoarthritis Initiative (OAI), studies of persons with or at high risk of OA. Subjects had long limb and repeated posteroanterior knee radiographs and completed the physical activity survey for the elderly (PASE). We studied persons without radiographic OA and excluded knees with major injury and without long limb films. We followed subjects 30 months (in MOST) and 48 months (in OAI) for one of two incident outcomes: (1) symptomatic tibiofemoral OA (radiographic OA and knee pain), or (2) tibiofemoral narrowing. 'Active' persons were those with PASE score in the highest quartile by gender. We examined risk of OA in active group using logistic regression adjusting for age, gender, body mass index (BMI), Western Ontario and McMaster Arthritis Index (WOMAC) pain score, Kellgren and Lawrence (KL) grade (0 or 1), and study of origin. We also analyzed knees from malaligned and neutrally aligned limbs. RESULTS: The combined sample comprised 2,073 subjects (3,542 knees) with mean age 61 years. The cumulative incidence of symptomatic tibiofemoral OA was 1.12% in the active group vs 1.82% in the others (odds ratio (OR) among active group 0.6, 95% confidence interval (CI) 0.3, 1.3). Joint space narrowing occurred in 3.41% of knees in the active group vs 4.04% in the others (OR among active group 0.9 (95% CI 0.5, 1.5)). Results did not differ by alignment status. CONCLUSIONS: Physical activity in the highest quartile did not affect the risk of developing OA.

Pre-radiographic MRI findings are associated with onset of knee symptoms: the most study.

OBJECTIVE: Magnetic resonance imaging (MRI) has greater sensitivity to detect osteoarthritis (OA) damage than radiographs but it is uncertain which MRI findings in early OA are clinically important. We examined MRI abnormalities detected in knees without radiographic OA and their association with incident knee symptoms. METHOD: Participants from the Multicenter Osteoarthritis Study (MOST) without frequent knee symptoms (FKS) at baseline were eligible if they also lacked radiographic features of OA at baseline. At 15 months, knees that developed FKS were defined as cases while control knees were drawn from those that remained without FKS. Baseline MRIs were scored at each subregion for cartilage lesions (CARTs); osteophytes (OST); bone marrow lesions (BML) and cysts. We compared cases and controls using marginal logistic regression models, adjusting for age, gender, race, body mass index (BMI), previous injury and clinic site. RESULTS: 36 case knees and 128 control knees were analyzed. MRI damage was common in both cases and controls. The presence of a severe CART (P=0.03), BML (P=0.02) or OST (P=0.02) in the whole knee joint was more common in cases while subchondral cysts did not differ significantly between cases and controls (P>0.1). Case status at 15 months was predicted by baseline damage at only two locations; a BML in the lateral patella (P=0.047) and at the tibial subspinous subregions (P=0.01). CONCLUSION: In knees without significant symptoms or radiographic features of OA, MRI lesions of OA in only a few specific locations preceded onset of clinical symptoms and suggest that changes in bone play a role in the early development of knee pain. Confirmation of these findings in other prospective studies of knee OA is warranted.

Does cartilage volume or thickness distinguish knees with and without mild radiographic osteoarthritis? The Framingham Study.

OBJECTIVES: To examine whether the quantity of cartilage or semiquantitative scores actually differ in knees with mild radiographic osteoarthritis compared with knees without osteoarthritis. METHODS: Framingham Osteoarthritis Study participants had knee tibiofemoral magnetic resonance imaging-based measurements of cartilage. Using three-dimensional FLASH-water excitation sequences, cartilage volume, thickness and subregional cartilage thickness were measured and cartilage scored semiquantitatively (using the whole-organ magnetic resonance imaging score; WORMS). Using weight-bearing radiographs, mild osteoarthritis was defined as Kellgren/Lawrence (K/L) grade 2 and non-osteoarthritis as K/L grade 0. Differences between osteoarthritis and non-osteoarthritis knees in median cartilage measurements were tested using the Wilcoxon rank sum test. RESULTS: Among 948 participants (one knee each), neither cartilage volume nor regional thickness were different in mild versus non-osteoarthritis knees. In mild osteoarthritis, cartilage erosions in focal areas were missed when cartilage was quantified over large regions such as the medial tibia. For some but not all subregions of cartilage, especially among men, cartilage thickness was lower (p<0.05) in mild osteoarthritis than non-osteoarthritis knees. Because semiquantitative scores captured focal erosions, median WORMS scores were higher in mild osteoarthritis than non-osteoarthritis (all p<0.05). In moderate/severe osteoarthritis (K/L grades 3 or 4), osteoarthritis knees had much lower cartilage thickness and higher WORMS scores than knees without osteoarthritis. CONCLUSIONS: In mild osteoarthritis, the focal loss of cartilage is missed by quantitative measures of cartilage volume or thickness over broad areas. Regional cartilage volume and thickness (eg, medial tibia) are not different in mild osteoarthritis versus non-osteoarthritis. Subregional thickness may be decreased in mild osteoarthritis. Semiquantitative scoring that assesses focal cartilage damage differentiates mild osteoarthritis from non-osteoarthritis.

Is obesity a risk factor for progressive radiographic knee osteoarthritis?

OBJECTIVE: To examine whether obesity increases the risk of progression of knee osteoarthritis (OA). METHODS: We used data from the Multicenter Osteoarthritis Study, a longitudinal study of persons with or at high risk of knee OA. OA was characterized at baseline and 30 months using posteroanterior fixed-flexion radiographs and Kellgren/Lawrence (K/L) grading, with alignment assessed on full-extremity films. In knees with OA at baseline (K/L grade 2 or 3), progression was defined as tibiofemoral joint space narrowing on the 30-month radiograph. In knees without OA at baseline (K/L grade 0 or 1), incident OA was defined as the development of radiographic OA at 30 months. Body mass index (BMI) at baseline was classified as normal (<25 kg/m(2)), overweight (25-<30 kg/m(2)), obese (30-<35 kg/m(2)), and very obese (>or=35 kg/m(2)). The risk of progression was tested in all knees and in subgroups categorized according to alignment. Analyses were adjusted for age, sex, knee injury, and bone density. RESULTS: Among the 2,623 subjects (5,159 knees), 60% were women, and the mean +/- SD age was 62.4 +/- 8.0 years. More than 80% of subjects were overweight or obese. At baseline, 36.4% of knees had tibiofemoral OA, and of those, only one-third were neutrally aligned. Compared with subjects with a normal BMI, those who were obese or very obese were at an increased risk of incident OA (relative risk 2.4 and 3.2, respectively [P for trend < 0.001]); this risk extended to knees from all alignment groups. Among knees with OA at baseline, there was no overall association between a high BMI and the risk of OA progression; however, an increased risk of progression was observed among knees with neutral but not varus alignment. The effect of obesity was intermediate in those with valgus alignment. CONCLUSION: Although obesity was a risk factor for incident knee OA, we observed no overall relationship between obesity and the progression of knee OA. Obesity was not associated with OA progression in knees with varus alignment; however, it did increase the risk of progression in knees with neutral or valgus alignment. Therefore, weight loss may not be effective in preventing progression of structural damage in OA knees with varus alignment.

The relation of plasma homocysteine to radiographic knee osteoarthritis.

OBJECTIVE: Homocysteine has been implicated in multiple diseases that involve changes in structural tissue. In vitro studies have found that it alters the structure of collagen cross-linking thus affecting stability and mineralization such as that occurring in bone tissue. In the present study we considered the possible relationship between plasma homocysteine levels and the development and progression of knee osteoarthritis (OA). METHODS: The study question was posed in 691 men and 966 women from the original and offspring cohorts of the Framingham Osteoarthritis Study. We divided individuals into three groups according to plasma homocysteine levels and compared their risk for the development of new and progression of existing OA. We adjusted for potential confounders including age, body mass index, weight change, and physical activity. RESULTS: In the crude analysis, men in the middle homocysteine tertile were found to be at a greater risk than men in the lowest tertile for incident OA [odds ratios of 1.9 (1.1-3.5)]. This result persisted after adjusting for covariates [odds: 2.0, (1.1-3.8)]. No significant correlation was seen in women for the development of OA. In the evaluation of progression no significant trends were seen for both men and women. CONCLUSIONS: Although cellular and molecular studies of homocysteine-related pathophysiology suggest a possible correlation between plasma homocysteine levels and OA, the present clinical study did not conclusively demonstrate such an association. However, further research is needed to explore the role of homocysteine in specific aspects of OA etiopathogenesis.

Knee alignment differences between Chinese and Caucasian subjects without osteoarthritis.

OBJECTIVE: Despite the lower prevalence of obesity (a known risk factor for osteoarthritis (OA)), the prevalence of lateral tibiofemoral OA is higher in Chinese communities compared with Caucasian communities. One potential explanation is the difference in knee alignment between the two populations. We measured various knee alignment indices among Chinese and Caucasians and assessed whether these indices were different between the two racial groups. METHODS: We selected participants from the Framingham Osteoarthritis Study (FOA) and the Beijing Osteoarthritis Study (BOA), all without knee OA (Kellgren & Lawrence grade <2). Bilateral, fully extended anteroposterior knee radiographs were measured for the following angles in both knees: the anatomic axis (AA), the condylar angle (CA), the tibial plateau angle and the condylar-plateau angle (CP). We compared the mean of each measurement between the two racial groups adjusting for age and body mass index using linear regression and stratified by sex. RESULTS: The mean AA, CA and CP were significantly different in the BOA compared with the FOA. For women, the mean AA and CA were significantly more valgus in BOA subjects, while in men, the mean AA and CP were more valgus in BOA subjects. CONCLUSIONS: There are significant differences in knee morphology between Chinese and Caucasian cohorts, which result in a more valgus alignment of the distal femur in Chinese. This would serve to shift the mechanical loading towards the lateral compartment, and provide a possible explanation why Chinese have a higher prevalence of lateral tibiofemoral OA.

The ratio of medial to lateral tibial plateau bone mineral density and compartment-specific tibiofemoral osteoarthritis.

INTRODUCTION: Bone is thought to play an important role in osteoarthritis (OA) pathophysiology. Our aim was to look at specific features of OA and their relation to the ratio of medial:lateral tibial plateau bone mineral density (M:L BMD Ratio). METHODS: We examined our research question in the Framingham OA Study Cohort. All participants had BMDs and weight-bearing plain radiographs of the knees (2002-2005). M:L BMD Ratios were calculated using BMD from medial and lateral regions in the tibial plateau. Knee x-rays were read for osteophytes (OSTs), joint space narrowing (JSN), and sclerosis (Osteoarthritis Research Society International (OARSI) scoring system). Knees were classified as having medial and/or lateral JSN if they had JSN >or=1 in the medial and/or lateral tibiofemoral compartments, respectively. Medial and/or lateral OSTs were defined as medial and/or lateral tibial and/or femoral OSTs >or=2, respectively. Medial sclerosis and lateral sclerosis were defined as medial and lateral tibial sclerosis >or=1, respectively. We performed a logistic regression with medial JSN as the outcome and with M:L BMD Ratio groups as predictor variables, using the median group as the referent. Analyses were adjusted for age, sex, and body mass index (BMI). Generalized estimating equations were used to adjust for correlation between knees. Identical analyses were performed with medial OSTs, medial sclerosis, lateral JSN, lateral OSTs, and lateral sclerosis as the outcomes. RESULTS: Mean age of 1612 subjects (3048 knees) was 63.9 (Standard Deviation (SD)+/-8.9), 56% were women, and mean BMI was 28.5 (SD+/-5.5). M:L BMD Ratio was positively associated with medial JSN (P for linear trend <0.0001) and negatively associated with lateral JSN (P for linear trend <0.0001). The relations of the ratio with medial and lateral OSTs were j-shaped with P for quadratic trends <0.0001. There were also strong associations between M:L BMD Ratio and compartment-specific sclerosis (P for linear trends <0.0001) with most knees with medial and lateral sclerosis being in the highest and lowest M:L BMD Ratio groups, respectively. CONCLUSION: In summary, the extremes of the M:L BMD Ratio are strongly associated with individual radiographic features of OA. These findings add to existing evidence supporting the importance of understanding bone in OA pathophysiology.

Trapeziometacarpal subluxation predisposes to incident trapeziometacarpal osteoarthritis (OA): the Framingham Study.

OBJECTIVE: Osteoarthritis (OA) of the thumb carpo-metacarpal joint is a common condition that can lead to substantial pain, instability, deformity, and loss of motion. It has been hypothesized that instability of the trapeziometacarpal joint combined with strenuous use can potentially lead to OA. However, as yet there have been no longitudinal evaluations to determine if this hypothesis is true. We examined the relation of radial subluxation to the risk of radiographic OA at trapeziometacarpal joint. METHODS: We conducted a nested case-control study. We restricted our evaluation of cases to subjects with no radiographic trapeziometacarpal OA at baseline (1967). We defined incident trapeziometacarpal OA as the development of a modified Kellgren and Lawrence grade>or=2 in that joint at a later examination (1992-1993). Radial subluxation of the base of the first metacarpal off the trapezium and the amount of the base of the first metacarpal covering the articulating surface of the trapezium were measured using a digital calculation caliper. We examined the relation of gender-specific quartile groups of radial subluxation to the risk of trapeziometacarpal OA using a conditional logistic regression model. RESULTS: We assessed 203 men and 431 women. After adjusting for age, handedness, number of other joints with OA, and grip strength, the odds ratios for the risk of trapeziometacarpal OA in men were 1.0, 1.8, 2.7, and 3.1 from the lowest quartile of radial subluxation to the highest quartile, respectively (P for trend=0.015). There was no significant relationship between radial subluxation quartiles and incident trapeziometacarpal OA in women. CONCLUSION: This study provides evidence that radial subluxation predisposes to subsequent OA of the trapeziometacarpal joint in men.

A genome scan for joint-specific hand osteoarthritis susceptibility: The Framingham Study.

OBJECTIVE: Studies investigating hand osteoarthritis (OA) as a single entity have not shown strong linkage of the disease with any chromosomal sites. We undertook this study to test our hypothesis that phenotypes of hand OA may show stronger linkage than has been shown for overall hand OA. METHODS: We performed a factor analysis on measures of hand OA to determine patterns of disease. Using the joint regions identified by this analysis, we performed a genome-wide linkage analysis for OA susceptibility loci using 426 original cohort members and 790 offspring cohort members in 267 pedigrees. Radiographic OA features evaluated included the Kellgren/Lawrence score, osteophytes, and joint space narrowing. Prior to linkage analysis, standardized residuals were computed from regression analysis of each phenotype on age. This was performed separately for each sex and cohort. The variance component model (GeneHunter) was then applied to the normalized scores of the residuals of both sexes and cohorts. RESULTS: There was evidence suggestive of linkage (logarithm of odds [LOD] score >1.5) at 16 sites. Four of these sites had LOD scores >3.0. Two of these sites (identified in the full sample) included a linkage region for OA of the distal interphalangeal (DIP) joint on chromosome 7 (155 cM; LOD score 3.06) and a linkage region for OA of the first carpometacarpal (CMC) joint on chromosome 15 (81 cM; LOD score 6.25). The other 2 sites (identified in women) included a linkage region for OA of the DIP joint on chromosome 1 (202 cM; LOD score 3.03) and a linkage region for OA of the first CMC joint on chromosome 20 (4 cM; LOD score 3.74). CONCLUSION: These data suggest that several chromosomes contain hand OA susceptibility genes and that a joint-specific approach may be more rewarding than a global approach to the genetics of hand OA. Further investigation of these regions is warranted using finer maps and other populations.

Symmetry and clustering of symptomatic hand osteoarthritis in elderly men and women: the Framingham Study.

OBJECTIVE: While symmetry and clustering of radiographic hand osteoarthritis (OA) have been described in middle-aged women, these have not been studied in elderly individuals and similar investigations are lacking for symptomatic hand OA. The goal of this study was to study patterns of joint involvement in symptomatic hand OA among elderly Caucasian men and women. METHODS: Using data from the Framingham Osteoarthritis Study, we defined a joint as having symptomatic OA if it had symptoms and radiographic OA (Kellgren and Lawrence grade > or =2). We assessed clustering of symptomatic OA using a chi(2)-test and evaluated the interrelationship of occurrence of symptomatic OA among different joints with generalized estimating equations. RESULTS: Of 976 subjects (age 71-99 yr, 36% men) examined, symptomatic OA more often affected multiple hand joints in an individual than would be expected by chance (P<0.001). The presence of symptomatic OA at a particular joint was strongly associated with symptomatic OA in the same joint of the opposite hand, followed by other joints in the same row of the same hand, and then other joints in the same ray of the same hand. The symmetrical pattern of symptomatic OA was more apparent in women than in men. CONCLUSION: Our study demonstrates that symptomatic OA often affects multiple hand joints, and is more likely to cluster by row than by ray. The disease also occurs in a remarkably symmetrical pattern, especially in women.

Genome scan for quantity of hand osteoarthritis: the Framingham Study.

OBJECTIVE: To search for markers linked to quantity of radiographic hand osteoarthritis (OA) in the Framingham Heart Study. METHODS: The sample included 684 original cohort members and 793 offspring in 296 pedigrees. Radiographic OA features evaluated included the Kellgren/Lawrence (K/L) score, osteophytes, and joint space narrowing (0-3 scale). Four quantitative phenotypes were computed from these measurements: sum of K/L scores across hand joints, sum of osteophyte scores, sum of joint space narrowing scores, and proportion of affected joints. Prior to linkage analysis, these phenotypes were adjusted for age using a linear regression analysis from which standardized residuals were computed. The regression analysis was performed separately for each sex and each generation. The variance component model (SOLAR) was then applied to the normalized scores of the residuals. RESULTS: The average age was 62 years for the original cohort and 54 years for the offspring. Fifty percent of the original cohort and 30% of their offspring had at least 1 affected joint (K/L score >or=2). Heritability ranged from 28% (proportion of joints affected with OA) to 34% (sum of K/L scores). Eight chromosomal regions indicated suggestive linkage (multipoint logarithm of odds [LOD] score >1.5) for at least 1 phenotype; LOD scores were highest for joint space narrowing, with a multipoint LOD score = 2.96 on chromosome 1p at D1S1665. Chromosomes 7, 9, 13, and 19 indicated consistent LOD score elevation for multiple OA phenotypes. CONCLUSION: There are several chromosomes that may harbor OA susceptibility genes. Further investigation of these regions using larger studies and finer maps will be important to confirm linkage.

Comparison of the prevalence of knee osteoarthritis between the elderly Chinese population in Beijing and whites in the United States: The Beijing Osteoarthritis Study.

OBJECTIVE: To estimate the prevalence of radiographic and symptomatic knee osteoarthritis (OA) in a population-based sample of elderly subjects in Beijing, China and compare it with that reported in the Framingham (Massachusetts) OA Study. METHODS: We recruited a sample of persons age > or = 60, using door-to-door enumeration in randomly selected neighborhoods in Beijing. Subjects completed a home interview including questions on knee symptoms and a hospital examination including knee radiographs obtained during weight bearing. The protocol was identical to that used in the Framingham OA Study. A reader read intermingled Beijing and Framingham Study films to ensure high reliability. We defined a subject as having radiographic knee OA when the Kellgren/Lawrence grade was > or = 2 in at least 1 knee. Symptomatic knee OA was recorded as present when knee pain was reported and the symptomatic knee had radiographic OA. We estimated the prevalence of these entities in elderly subjects in Beijing and compared it with OA prevalence in Framingham, using an age-standardized prevalence ratio. RESULTS: Of 2,180 age-eligible Beijing subjects contacted, knee radiographs were obtained in 1,787 (82.0%). The prevalence of radiographic knee OA was 42.8% in women and 21.5% in men. Symptomatic knee OA occurred in 15.0% of women and 5.6% of men. Compared with women of the same age in Framingham, women in Beijing had a higher prevalence of radiographic knee OA (prevalence ratio 1.45, 95% confidence interval 1.31-1.60) and of symptomatic knee OA (prevalence ratio 1.43, 95% confidence interval 1.16-1.75). The prevalence of knee OA in Chinese men was similar to that in their white US counterparts (for radiographic OA, prevalence ratio 0.90; for symptomatic OA, prevalence ratio 1.02). CONCLUSION: Using identical methods and definitions to evaluate the prevalence of OA across populations, we found, surprisingly, that older Chinese women have a higher prevalence of knee OA than women in Framingham, Massachusetts. The prevalence in men was comparable. Possible explanations for these differences range from genetic differences to heavy physical activity among Chinese.

Long-term follow-up of residual mediastinal-hilar Ga-67 uptake after treatment for Hodgkin's and non-Hodgkin's lymphomas: what degree of Ga-67 uptake is significant?

PURPOSE: Ga-67 planar and SPECT images of 85 patients after treatment for mediastinal-hilar (M-H) lymphoma were reviewed retrospectively. Forty-seven patients had Hodgkin's disease and 38 patients had non-Hodgkin's lymphoma. The entire period was 7 years after diagnosis. The main goal was visual assessment of the significance of mild (grades 1 or 2) Ga-67 uptake in the M-H area as compared with Ga-67 uptake in bone marrow. METHODS: Residual Ga-67 mediastinal uptake after a complete course of chemotherapy or other treatments was defined as normal (no residual) M-H uptake, borderline (M-H residual uptake with intensity less than that or equal to the sternum, spine, or both), and abnormal (M-H residual uptake with intensity greater than that of the sternum or spine). RESULTS: Among the 38 patients (45%) with no residual M-H uptake, four (one Hodgkin's disease and three non-Hodgkin's lymphoma) experienced recurrence: two in the mediastinum and two in the abdomen. Among the 45 patients (53%) with borderline M-H uptake, five experienced recurrence: two in the mediastinum and three in other sites. The two patients (2%) with abnormal (M-H) uptake never responded to treatment. No significant statistical difference in tumor recurrence was found between no residual and borderline uptake (P = 0.21). CONCLUSIONS: Visual assessment of M-H Ga-67 uptake (without quantification) could be useful to differentiate active residual tumor from nonactive residual uptake.

MR imaging of arthritides of the cervical spine.

Indications for MR imaging have broadened with the development of multiplanar capability, superb soft tissue contrast, and high sensitivity for detecting pathologic alterations. These developments are especially valuable in the analysis of the spine, where multiple anatomic structures reside, each with varying physical properties. MR imaging is unsurpassed in demonstrating early structural and proliferative changes that occur in inflammatory and related arthritides, and in evaluating complications that can cause significant morbidity, and even death. The role of MR imaging in the evaluation of cervical spinal arthritis continues to evolve, as its role in identifying patients for surgical intervention becomes clearer.

Bone mineral density and risk of incident and progressive radiographic knee osteoarthritis in women: the Framingham Study.

OBJECTIVE: To examine the relations of bone mineral density (BMD) and change in BMD to risk of incident and progressive radiographic knee osteoarthritis (OA) in a longitudinal cohort study. METHODS: Female participants aged 63 to 91 years (mean age 71) in the Framingham Study received anteroposterior weight bearing knee radiographs at biennial examinations 18 (1983-85) and 22 (1992-93). Knee radiographs were given scores for global severity of OA (Kellgren-Lawrence scale: range 0 to 4) and for the presence of osteophytes and joint space narrowing (range 0 to 3). Femoral neck BMD was assessed using dual photon absorptiometry at examination 20 and dual x-ray absorptiometry at examination 22. We examined the relations of BMD at examination 20 and its change between examination 20 and examination 22 to incident and progressive knee OA, as well as to worsening of individual radiographic features adjusting for age, body mass index, and other potential confounding factors. RESULTS: In total, 473 women (ages 63 to 91 yrs) had complete assessments. Over 8 years of followup, risk of incident radiographic knee OA increased from 5.6% among women in the lowest age-specific quartile of BMD to 14.2, 10.3, and 11.8% among women in the 2nd, 3rd, and highest quartiles, respectively. Multivariate adjusted OR of incident OA for each increase quartile of BMD were 1.0, 2.5, 2.0, and 2.3, respectively (p for trend = 0.222). This was mainly reflected in an increased risk of osteophyte development. However, risk of progressive OA decreased from 34.4 to 22.0, 20.3, and 18.9% as BMD increased. Compared to those in the lowest quartile of BMD, adjusted OR for progressive disease were 0.3, 0.2, and 0.1 among women in the 2nd, 3rd, and highest quartiles (p for trend <0.001), respectively, mainly due to its effect on lowering the risk of joint space loss. Compared to those who lost BMD >0.04 g/cm2 over the followup period, women who gained BMD were at increased risk of incident but at a significantly decreased risk of progressive knee OA. BMD change was not associated with osteophyte development, but gain in BMD lowered the risk of joint space loss. CONCLUSION: High BMD and BMD gain decreased the risk of progression of radiographic knee OA, but may be associated with an increased risk of incident knee OA. The protective effect was mainly through its influence on reducing the risk of joint space loss. Our results offer insights into how bone may affect the course of the most common joint disease, and thus may have potential therapeutic implications.

Level of physical activity and the risk of radiographic and symptomatic knee osteoarthritis in the elderly: the Framingham study.

PURPOSE: Because osteoarthritis may be caused by "wear and tear," we examined the association between level of physical activity and risk of knee osteoarthritis in the elderly. SUBJECTS AND METHODS: Eligible subjects were participants in the Framingham Heart Study cohort who had radiographically normal knees at biennial exam 18 (1983-1985) and who also completed a physical activity questionnaire at exam 20 (1988-1989). Follow-up knee radiographs were obtained at biennial exam 22 (1992-1993). The study outcomes were the development of incident radiographic or symptomatic knee osteoarthritis between the baseline and follow-up exams. RESULTS: The number of hours per day of heavy physical activity was associated with the risk of incident radiographic knee osteoarthritis (odds ratio = 1.3 per hour, 95% confidence limits 1.1-1.6, P for trend = 0.006). Adjustment for age, sex, body mass index, weight loss, knee injury, health status, total calorie intake, and smoking strengthened this association (eg, odds ratio for > or = 4 hours heavy physical activity/day compared with no heavy physical activity = 7.0, 95% confidence limits 2.4-20, P for trend = 0.0002). Risk was greatest among individuals in the upper tertile of body mass index (odds ratio for > or = 3 hours/day of heavy physical activity = 13.0, 95% confidence limits 3.3-51). For incident symptomatic knee osteoarthritis, the results were similar, although the number of cases was small. No effects on these outcomes were observed from moderate and light physical activity, number of blocks walked, or number of flights of stairs climbed daily. CONCLUSIONS: Heavy physical activity is an important risk factor for the development of knee osteoarthritis in the elderly, especially among obese individuals. Light and moderate activities do not appear to increase risk.

Hip arthrography, aspiration, block, and bursography.

Hip arthrography in children with Legg-Calvé-Perthes disease is used to determine the optimal position of the femoral head for immobilization during the process of epiphyseal healing and in developmental dysplasia of the hip as a guide to operative treatment. In adult hips, arthrography and aspiration are useful techniques for demonstration of prosthetic implant loosening and infection. Aspiration of the hip joint and culture of aspirated fluid helps to diagnose septic arthritis. Anesthetic hip arthrography helps to distinguish between pain originating from the hip and radicular pain from the spine. Iliopsoas bursography may be used to diagnose bursal enlargement and its cause.