Associations between anterior knee pain and 2-year patellofemoral cartilage worsening: The MOST study

OBJECTIVE

Anterior knee pain (AKP) is associated with patellofemoral osteoarthritis (PFOA), but longitudinal studies are lacking. If AKP precedes PFOA, it may create an opportunity to identify and intervene earlier in the disease process. The purpose of this study was to examine the longitudinal relation of AKP to worsening patellofemoral (PF) cartilage over two years.

DESIGN

Participants were recruited from the Multicenter Osteoarthritis Study, a longitudinal study of individuals with or at risk for knee osteoarthritis (OA). Exclusion criteria included bilateral knee replacements, arthritis other than OA, and radiographic PFOA. At baseline, participants completed a knee pain map questionnaire and underwent knee magnetic resonance imaging (MRI). Imaging was repeated at 2-year follow-up. Exposure was presence of frequent AKP. Outcome was worsening cartilage damage in the PF joint defined as increase in MRI Osteoarthritis Knee Score from baseline to 2 years. Log-binomial models were used to calculate risk ratios (RR).

RESULTS

One knee from 1083 participants (age 56.7 ± 6.6 years; body mass index 28.0 ± 4.9 kg/m2) was included. Frequent AKP and frequent isolated AKP were present at baseline in 14.5% and 3.6%, respectively. Frequent AKP was associated with an increased risk (RR: 1.78, 95% confidence interval: 1.21, 2.62) of 2-year worsening cartilage damage in the lateral PF compartment. No association was found between frequent AKP and worsening in the medial PF joint.

CONCLUSION

Frequent AKP at baseline was associated with worsening cartilage damage in the lateral PF joint over 2 years.

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).

Alkylresorcinol, a biomarker for whole grain intake, and its association with osteoarthritis: the MOST study

INTRODUCTION

Higher intake of fiber has been associated with lower risk of incident symptomatic osteoarthritis (OA). We examined whether levels of alkylresorcinol (AR), a marker of whole grain intake, were associated with OA in subjects in The Multicenter Osteoarthritis (MOST) Study.

METHOD

Knee x-rays and knee pain were assessed at baseline and through 60-months. Stored baseline fasting plasma samples were analyzed for AR homologues (C17:0, C19:0, C21:0, C23:0, C25:0) and total AR levels (AR sum). Two nested case-control studies, one for incident radiographic OA and one for incident symptomatic OA were performed with participants re-assessed at 15, 30 and 60 months. Multivariable conditional logistic regression with baseline covariates including age, sex, BMI, physical activity, quadriceps strength, race, smoking, depressive symptoms, diabetes and knee injury tested the association of log transformed AR levels with OA outcomes.

RESULTS

Seven hundred seventy-seven subjects were, on average, in their 60's, and most were women. For 60-month cumulative incidence, there was no significant association between quartiles of AR concentration and incident radiographic (e.g., for incident radiographic OA, highest vs lowest quartile of AR sum showed RR = 0.93 (95% CI 0.59, 1.47), and for symptomatic OA RR was 1.22 (95% CI 0.76, 1.94). In secondary analyses examining 30-month incidence, high AR levels were associated with a reduced risk of X-ray OA (RR = 0.31 (95% CI 0.15, 0.64).

CONCLUSION

In primary analyses, AR levels were not associated with risk of OA, but secondary analyses left open the possibility that high AR levels may protect against OA.

Heterogeneity of cartilage damage in Kellgren and Lawrence grade 2 and 3 knees: the MOST study

OBJECTIVE

Eligibility for clinical trials in osteoarthritis (OA) is usually limited to Kellgren-Lawrence (KL) grades 2 and 3 knees. Our aim was to describe the prevalence and severity of cartilage damage in KL 2 and 3 knees by compartment and articular subregion.

DESIGN

The Multicenter Osteoarthritis (MOST) study is a cohort study of individuals with or at risk for knee OA. All baseline MRIs with radiographic disease severity KL2 and 3 were included. Knee MRIs were read for cartilage damage in 14 subregions. We determined the frequencies of no, any and widespread full-thickness cartilage damage by knee compartment, and the prevalence of any cartilage damage in 14 articular subregions.

RESULTS

665 knees from 665 participants were included (mean age 63.8 ± 7.9 years, 66.5% women). 372 knees were KL2 and 293 knees were KL3. There was no cartilage damage in 78 (21.0%) medial tibio-femoral joint (TFJ), 157 (42.2%) lateral TFJ and 62 (16.7%) patello-femoral joint (PFJ) compartments of KL2 knees, and 17 (5.8%), 115 (39.3%) and 35 (12.0%) compartments, respectively, of KL3 knees. There was widespread full-thickness damage in 94 (25.3%) medial TFJ, 36 (9.7%) lateral TFJ and 176 (47.3%) PFJ compartments of KL2 knees, and 217 (74.1%), 70 (23.9%) and 104 (35.5%) compartments, respectively, of KL3 knees. The subregions most likely to have any damage were central medial femur (80.5%), medial patella (69.8%) and central medial tibia (69.9).

CONCLUSIONS

KL2 and KL3 knees vary greatly in cartilage morphology. Heterogeneity in the prevalence, severity and location of cartilage damage in in KL2 and 3 knees should be considered when planning disease modifying trials for knee OA.

The association of frontal plane alignment to MRI-defined worsening of patellofemoral osteoarthritis: the MOST study

OBJECTIVE

To determine the sex-specific relation of frontal plane alignment (FPA) to magnetic resonance imaging (MRI)-defined features of patellofemoral osteoarthritis, and also to tibiofemoral osteoarthritis and knee pain.

METHOD

The Multicenter Osteoarthritis Study is cohort study comprised of individuals with or at risk of knee osteoarthritis. We determined the sex-specific dose-response relation of baseline FPA to MRI-defined patellofemoral and tibiofemoral structural worsening, and incident knee pain, over 7 years.

RESULTS

In women only, greater varus alignment was associated with medial patellofemoral osteophytes (risk ratio [RR] 1.7 [95% CI 1.2, 2.6]) and valgus with lateral patellofemoral osteophytes (RR 1.9 [1.0, 3.6]). In men, greater varus increased risk for medial tibiofemoral cartilage worsening (RR 1.7 [1.1, 2.6]), and valgus for lateral tibiofemoral cartilage worsening (RR 1.8 [1.6, 2.2]). In women, findings were similar for tibiofemoral cartilage, but varus also increased risk for medial bone marrow lesions [BMLs] (RR 2.2 [1.6, 3.1]) and medial osteophytes (RR 1.8 [1.3, 2.5]), and valgus for lateral BMLs (RR 3.3 [2.2, 4.5]) and osteophytes (RR 2.0 [1.2, 3.2]). Varus increased risk of incident pain in men (RR 1.7 [1.4, 2.2]) and women (RR 1.3 [1.0, 1.6]), valgus did so in men only (RR 1.5 [1.1, 1.9]).

CONCLUSION

FPA was associated with patellofemoral osteophyte worsening in women, though overall was more strongly associated with tibiofemoral than patellofemoral osteoarthritis feature worsening. FPA in women was more consistently associated with structural worsening, yet men had higher associations with incident pain.

Is the atrophic phenotype of tibiofemoral osteoarthritis associated with faster progression of disease? The MOST study

OBJECTIVE

To assess the associations of atrophic tibiofemoral osteoarthritis (OA) with progression of radiographic joint space narrowing (JSN) and magnetic resonance imaging (MRI)-defined progression of cartilage damage.

DESIGN

Participants of the Multicenter Osteoarthritis (MOST) Study with available radiographic and MRI assessments at baseline and 30 months were included. The atrophic OA phenotype was defined as Osteoarthritis Research Society International (OARSI) grades 1 or 2 for JSN and grade 0 for osteophytes. Based on MRI, atrophic OA was defined as tibiofemoral (TF) cartilage damage grades ≥3 in at least 2 of 10 subregions with absent or tiny osteophytes in all TF subregions. Progression of JSN and cartilage loss on MRI, was defined as (1) no, (2) slow, and (3) fast progression. Co-variance and logistic regression with generalized estimated equations were performed to assess the association of atrophic knee OA with any progression, compared to non-atrophic OA knees.

RESULTS

A total of 476 knees from 432 participants were included. There were 50 (10.5%) knees with atrophic OA using the radiographic definition, and 16 (3.4%) knees with atrophic OA using MRI definition. Non-atrophic OA knees more commonly exhibited fast progression of JSN and cartilage damage. Logistic regression showed that the atrophic phenotype of knee OA was associated with a decreased likelihood of progression of JSN and cartilage loss.

CONCLUSION

In this sample, the atrophic phenotype of knee OA was associated with a decreased likelihood of progression of JSN and cartilage loss compared to the non-atrophic knee OA phenotype.

Is superolateral Hoffa's fat pad hyperintensity a marker of local patellofemoral joint disease? - The MOST study

PURPOSE

To determine the relation of superolateral Hoffa's fat pad (SHFP) hyperintensity to cartilage damage and bone marrow lesions (BMLs) in the patellofemoral joint (PFJ) and tibiofemoral joint (TFJ).

METHODS

We used data from the 60 and 84-month study visits from the Multicenter Osteoarthritis (MOST) study. SHFP hyperintensity and Hoffa-synovitis were graded from 0 to 3. Cartilage damage and BMLs were scored in the PFJ and TFJ. Structural damage was defined as: any cartilage damage, full-thickness cartilage damage and any BML. Worsening structural damage was defined as any increase in cartilage and BML scores. Logistic regression was used to determine the relation of SHFP hyperintensity and Hoffa-synovitis (>0) to structural damage, adjusting for age, sex and body mass index (BMI).

RESULTS

1,094 knees were included in the study. Compared to knees without SHFP hyperintensity, those with SHFP hyperintensity had 1.2 (95% Confidence Interval (CI), 1.1-1.4), 1.7 (1.3-2.3) and 1.6 (1.3-1.9) times the prevalence of any cartilage damage, full-thickness cartilage damage, and BMLs in the lateral PFJ respectively, and 1.1 (1.0-1.2), 1.3 (1.0-1.8), and 1.2 (1.0-1.4) times the prevalence of any cartilage damage, full-thickness cartilage damage, and BMLs in the medial PFJ. SHFP hyperintensity was associated with worsening BMLs in the medial PFJ (RR: 1.4 (1.0-1.9)). In general, there was no relation between SHFP hyperintensity and TFJ outcomes. Hoffa-synovitis was associated both cross-sectionally and longitudinally with structural damage, regardless of definition, in all compartments.

CONCLUSION

SHFP hyperintensity may be a local marker of PFJ structural damage.

Varus thrust during walking and the risk of incident and worsening medial tibiofemoral MRI lesions: the Multicenter Osteoarthritis Study

OBJECTIVE

To determine the association of varus thrust during walking to incident and worsening medial tibiofemoral cartilage damage and bone marrow lesions (BMLs) over 2 years in older adults with or at risk for osteoarthritis (OA).

METHOD

Subjects from the Multicenter Osteoarthritis Study (MOST) were studied. Varus thrust was visually assessed from high-speed videos of forward walking trials. Baseline and two-year MRIs were acquired from one knee per subject and read for cartilage loss and BMLs. Logistic regression with generalized estimating equations was used to estimate the odds of incident and worsening cartilage loss and BMLs, adjusting for age, sex, race, body mass index (BMI), and clinic site. The analysis was repeated stratified by varus, neutral, and valgus alignment.

RESULTS

1007 participants contributed one knee each. Varus thrust was observed in 29.9% of knees. Knees with thrust had 2.17 [95% CI: 1.51, 3.11] times the odds of incident medial BML, 2.51 [1.85, 3.40] times the odds of worsening medial BML, and 1.85 [1.35, 2.55] times the odds of worsening medial cartilage loss. When stratified by alignment, varus knees also had significantly increased odds of these outcomes.

CONCLUSION

Varus thrust observed during walking is associated with increased odds of incident and worsening medial BMLs and worsening medial cartilage loss. Increased odds of these outcomes persist in varus-aligned knees.

Baseline radiographic osteoarthritis and semi-quantitatively assessed meniscal damage and extrusion and cartilage damage on MRI is related to quantitatively defined cartilage thickness loss in knee osteoarthritis: the Multicenter Osteoarthritis Study

OBJECTIVES

To provide a comprehensive simultaneous relation of various semiquantitative knee OA MRI features as well as the presence of baseline radiographic osteoarthritis (OA) to quantitative longitudinal cartilage loss.

METHODS

We studied Multicenter OA Study (MOST) participants from a longitudinal observational study that included quantitative MRI measurement of cartilage thickness. These subjects also had Whole Organ MRI Score (WORMS) scoring of cartilage damage, bone marrow lesions (BMLs), meniscal pathology, and synovitis, as well as baseline radiographic evaluation for Kellgren and Lawrence (KL) grading. Knee compartments were classified as progressors when exceeding thresholds of measurement variability in normal knees. All potential risk factors of cartilage loss were dichotomized into "present" (score ≥2 for cartilage, ≥1 for others) or "absent". Differences in baseline scores of ipsi-compartmental risk factors were compared between progressor and non-progressor knees by multivariable logistic regression, adjusting for age, sex, body mass index, alignment axis (degrees) and baseline KL grade. Odds ratios (OR) and 95% CIs were calculated for medial femorotibial compartment (MFTC) and lateral femorotibial compartment (LFTC) cartilage loss. Cartilage loss across both compartments was studied using Generalized Estimating Equations.

RESULTS

196 knees of 196 participants were included (age 59.8 ± 6.3 years [mean ± SD], BMI 29.5 ± 4.6, 62% women). For combined analyses of MFTC and LFTC, baseline factors related to cartilage loss were radiographic OA (KL grade ≥2: aOR 4.8 [2.4-9.5], cartilage damage (aOR 2.3 [1.2-4.4])), meniscal damage (aOR 3.9 [2.1-7.4]) and extrusion (aOR 2.9 [1.6-5.3]), all in the ipsilateral compartment, but not BMLs or synovitis.

CONCLUSION

Baseline radiographic OA and semiquantitatively (SQ) assessed MRI-detected cartilage damage, meniscal damage and extrusion, but not BMLs or synovitis is related to quantitatively measured ipsi-compartmental cartilage thinning over 30 months.

Progression of cartilage damage and meniscal pathology over 30 months is associated with an increase in radiographic tibiofemoral joint space narrowing in persons with knee OA--the MOST study

PURPOSE

To determine the association of MRI-assessed worsening of tibiofemoral cartilage damage, meniscal damage, meniscal extrusion, separately and together, with progression of radiographic joint space narrowing (JSN).

METHOD AND MATERIALS

The Multicenter Osteoarthitis Study (MOST) Study is a cohort study of subjects with or at risk for knee osteoarthritis (OA). Knees with radiographic OA Kellgren-Lawrence grade 2 at baseline and with baseline and 30-month 1.0 T MRIs were selected for reading using the WORMS system for cartilage damage, meniscal damage, and meniscal extrusion. The association of worsening of cartilage damage, meniscal damage, and/or meniscal extrusion with increases in the JSN was performed using logistic regression.

RESULTS

A total of 276 knees (one per subject) were included (women 68.5%, mean age 62.9 ± 7.8, mean body mass index (BMI) 30.2 ± 5.0). Worsening of each MRI feature was associated with any increase in JSN (P < 0.01). Worsening of cartilage damage was more frequently observed than worsening of meniscal damage and extrusion, and was significantly associated with both slow and fast progression of JSN. An increasing risk of JSN worsening was associated with increasing number of worsening MRI features (P for trend < 0.0001).

CONCLUSION

Worsening of tibiofemoral cartilage damage, meniscal damage, and meniscal extrusion are independent predictors of JSN progression in the same compartment. Worsening of cartilage damage is more frequently observed in JSN when compared to meniscal worsening. A strong cumulative effect on JSN progression is observed for worsening of more than one MRI feature.

High plasma levels of vitamin C and E are associated with incident radiographic knee osteoarthritis

BACKGROUND

Previous studies suggest that the antioxidants vitamins C and E may protect against development of knee osteoarthritis (OA). We examined the association of circulating levels of vitamin C and E with incident whole knee radiographic OA (WKROA).

METHODS

We performed a nested case-control study of incident WKROA in MOST, a cohort of 3,026 men and women aged 50-79 years with, or at high risk of, knee OA. Incident cases were knees without either tibiofemoral (TF) or patellofemoral (PF) OA at baseline that developed TF and/or PF OA by 30-month follow-up. Two control knees per case were selected from those eligible for WKROA that did not develop it. Vitamin C and E (alpha-tocopherol) assays were done on baseline supernatant plasma (PCA) and serum samples, respectively. We examined the association of gender-specific tertiles of vitamin C and E with incident WKROA using logistic regression with GEE, adjusting for age, gender, and obesity.

RESULTS

Subjects without WKROA at baseline who were in the highest tertile of vitamin C had a higher incidence of WKROA [adjusted OR = 2.20 (95% CI: 1.12-4.33); P-value = 0.021], with similar results for the highest tertile of vitamin E [adjusted OR = 1.89 (1.02-3.50); P-value = 0.042], compared to those in the lowest tertiles. P-values for the trend of vitamin C and E tertiles and incident WKROA were 0.019 and 0.030, respectively.

CONCLUSIONS

Higher levels of circulating vitamin C and E did not provide protection against incident radiographic knee OA, and may be associated with an increased risk of knee OA.

Prevalent cartilage damage and cartilage loss over time are associated with incident bone marrow lesions in the tibiofemoral compartments: the MOST study

OBJECTIVE

To assess the association of prevalent cartilage damage and cartilage loss over time with incident bone marrow lesions (BMLs) in the same subregion of the tibiofemoral compartments as detected on magnetic resonance imaging (MRI).

METHODS

The Multicenter Osteoarthritis Study is an observational study of individuals with or at risk for knee osteoarthritis (OA). Subjects whose baseline and 30-month follow-up MRIs were read for findings of OA were included. MRI was performed with a 1.0 T extremity system. Tibiofemoral compartments were divided into 10 subregions. Cartilage morphology was scored from 0 to 6 and BMLs were scored from 0 to 3. Prevalent cartilage damage and cartilage loss over time were considered predictors of incident BMLs. Associations were assessed using logistic regression, with adjustments for potential confounders.

RESULTS

Medially, incident BMLs were associated with baseline cartilage damage (adjusted odds ratio (OR) 3.9 [95% confidence interval (CI) 3.0, 5.1]), incident cartilage loss (7.3 [95% CI 5.0, 10.7]) and progression of cartilage loss (7.6 [95% CI 5.1, 11.3]) Laterally, incident BMLs were associated with baseline cartilage damage (4.1 [95% CI 2.6, 6.3]), incident cartilage loss (6.0 [95% CI 3.1, 11.8]), and progression of cartilage loss (11.9 [95% CI 6.2, 23.0]).

CONCLUSION

Prevalent cartilage damage and cartilage loss over time are strongly associated with incident BMLs in the same subregion, supporting the significance of the close interrelation of the osteochondral unit in the progression of knee OA.

Consistency of knee pain: correlates and association with function

OBJECTIVE

The extent and factors associated with knee pain fluctuation are not well-known. We evaluated the prevalence, correlates, and association with function of consistency of knee pain.

DESIGN

Participants of the Multicenter Osteoarthritis (MOST) Study, a cohort of individuals with or at high risk of knee osteoarthritis (OA) had baseline knee X-rays, questionnaires, and a question about frequent knee pain (FKnP) (pain on most of the past 30 days) at two time points: a telephone screen and a later clinic visit. We computed the prevalence of inconsistent knee pain (positive answer to FKnP question at only one time point) and consistent knee pain (positive answer to FKnP question at both time points). We evaluated the association of consistency of FKnP with a number of sociodemographic factors, pain severity, and function.

RESULTS

There were 2940 participants with complete data (5867 knees) [mean age 62, mean body mass index (BMI) 30.7, 60% female]. Of those, 2977 knees had pain, with 43% having inconsistent and 57% having consistent knee pain. Those with radiographic OA [odds ratio (OR) 0.46], depressive symptoms (OR 0.73), and widespread pain (OR 0.68) (all P<0.05) were less likely to have inconsistent compared with consistent knee pain. Pain, function, and strength were significantly better in persons with two knees that had inconsistent compared with consistent pain.

CONCLUSIONS

A substantial proportion of persons with knee pain have inconsistent knee pain, associated with better physical function and strength (adjusting for pain severity). Such pain may be suggestive of an earlier stage of disease.

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.

The association of meniscal damage with joint effusion in persons without radiographic osteoarthritis: the Framingham and MOST osteoarthritis studies

OBJECTIVE

To assess the cross-sectional association between meniscal status and joint effusion on magnetic resonance imaging (MRI) in knees without radiographic osteoarthritis (OA).

DESIGN

Knees without OA (Kellgren/Lawrence grade 0) from the Framingham and MOST studies were examined by MRI. Meniscal status was assessed with a score of 0-4 in the anterior horn/body/posterior horn of the medial/lateral meniscus and effusion was assessed using a score of 0-3. The odds ratios (ORs) of joint effusion in those with meniscal damage were estimated using a logistic regression model. A subanalysis was performed for knees without MRI-detected cartilage damage.

RESULTS

Of 1368 knees, 296 (21.6%) showed meniscal pathology in at least one subregion. Effusion was present in 133 (44.9%) of knees with meniscal damage vs 328 (30.6%) in those without meniscal damage. The adjusted OR of effusion in a knee with meniscal damage was 1.8, 95% confidence intervals (CI) [1.4, 2.4]. The OR of effusion for the group with meniscal pathology in two compartments was 5.4, 95% CI [2.1, 14.3]. For knees without any cartilage lesions but with meniscal damage in any compartment the OR was 2.3, 95% CI [1.1, 4.5].

CONCLUSIONS

Knees without OA but with meniscal pathology exhibit joint effusion to a significantly higher degree than knees without meniscal damage. The association persists for knees without cartilage damage. The prevalence of effusion is further increased when present in two compartments. Concomitant occurrence of synovial activation and meniscal damage contributes to understanding the pathophysiology of early degenerative joint disease.

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.

Change in MRI-detected subchondral bone marrow lesions is associated with cartilage loss: the MOST Study. A longitudinal multicentre study of knee osteoarthritis

OBJECTIVES

To describe the natural history of subchondral bone marrow lesions (BMLs) in a sample of subjects with knee osteoarthritis (OA) or at risk of developing it. Additionally, to examine the association of change in BMLs from baseline to 30-month follow-up with the risk of cartilage loss in the same subregion at follow-up.

METHODS

1.0 T MRI was performed using proton density-weighted, fat-suppressed sequences. BML size and cartilage status were scored in the same subregions according to the WORMS system. Subregions were categorised based on comparison of baseline and follow-up BML status. A logistic regression model was used to assess the association of change in BML status with cartilage loss over 30 months using stable BMLs as the reference group.

RESULTS

395 knees were included. 66% of prevalent BMLs changed in size; 50% showed either regression or resolution at follow-up. The adjusted odds ratios (95% confidence intervals) of cartilage loss in the same subregion at follow-up for the different groups were 1.2 (0.5 to 1.6) for regressing BMLs, 0.9 (0.5 to 1.6) for resolving BMLs, 2.8 (1.5 to 5.2) for progressing BMLs, 0.2 (0.1 to 0.3) for subregions with no BMLs at baseline and follow-up and 3.5 (2.1 to 5.9) for newly developing BMLs. BML size at baseline was associated with risk of subsequent cartilage loss.

CONCLUSIONS

The majority of pre-existing BMLs decreased in size at follow-up. Absence of BMLs was associated with a decreased risk of cartilage loss, while progressing and new BMLs showed a high risk of cartilage loss in the same subregion.

Spinal stability with anterior or posterior ray threaded fusion cages

OBJECT

The authors conducted a study to determine if the rigidity supplied to the spine by posterior placement of the Ray threaded fusion cage (TFC) is further enhanced by the placement of pedicle screws and, additionally, if bilateral anteriorly placed TFCs render the spine more rigid than a single anteriorly placed TFC.

METHODS

Ten human cadaveric spinal specimens (L2-S1) were affixed within a testing frame. Loads of 1.5, 3, 4.5, and 6 Nm were applied to the spine in six degrees of freedom: flexion-extension, right and left lateral bending, and right and left axial rotation. Motion in an x, y, and z cartesian axis system was tracked using dual video cameras following light-emitting diodes attached to the spine and base plate. Load testing of the spines was performed in the intact mode, following which the spinal segments were randomized to receive anterior or posterior instrumentation. In five spine specimens we performed posterior discectomy, posterior lumbar interbody fusion (PLIF) with placement of femoral rings and pedicle screws, PLIF with bilateral TFCs, and bilateral TFCs with pedicle screws. Five other spines underwent anterior-approach discectomy, followed by implantation of a unilateral cage and bilateral cages. Load testing was performed after each step.

CONCLUSION

Spines in which PLIF with pedicle screws and TFCs with pedicle screws were placed were more rigid than after discectomy in all directions of motion except flexion. Anterior discectomy provided significantly (p < or = 0.05) less stability in left and right axial rotation than the intact spines and following posterior discectomy. Following anterior implantation of bilateral TFCs, spines were significantly more rigid than after discectomy in all directions except extension.

Biomechanical studies of a dynamized anterior thoracolumbar implant

STUDY DESIGN

An in vitro investigation into the biomechanical properties of a dynamized anterolateral compression implant that allows controlled subsidence.

OBJECTIVES

To determine the extent to which both modes of the anterolateral compression implant (controlled collapsing and rigid) are able to reestablish the stability of the lumbar spine after L4 corpectomy.

SUMMARY OF BACKGROUND DATA

Over time, anterior and posterior spinal implants have been associated with progressive angulation, and occasionally implant failure and breakage. To circumvent this occurrence and provide better graft loading, dynamized or collapsing devices for clinical use have been developed.

METHODS

Eight fresh calf spines (L1-L6) were placed in a biomechanical testing frame. Pure moments of 6 Nm were loaded onto the intact spine in six directions: flexion, extension, right and left lateral bending, and right and left axial rotation. A total L4 corpectomy then was performed, and the defect grafted with a wooden dowel. Loading was repeated after the specimens were stabilized using the two modes of the anterolateral compression implant in succession.

RESULTS

The results showed that both modes of the implant (the rigid mode in particular) restore the stiffness of the unstable spine to normal levels of flexion, extension, and right and left lateral bending, even to levels exceeding normal. These devices, however, fall short of achieving normal stability in right and left axial rotation.

CONCLUSION

In the cadaveric calf spine after L4 corpectomy, restoration of stability with a dynamized anterior spinal implant is possible in flexion, extension, and right and left lateral bending, but not in axial rotation.

Biomechanical studies on two anterior thoracolumbar implants in cadaveric spines

STUDY DESIGN

A biomechanical comparison of two commonly used anterior spinal devices: the Smooth Rod Kaneda and the Synthes Anterior Thoracolumbar Spinal Plate.

OBJECTIVES

To compare the stability imparted to the human cadaveric spine by the Smooth Rod Kaneda and Synthes Anterior Spinal Plate, and to assess how well these devices withstand fatigue and uni- and bilateral facetectomy.

SUMMARY OF BACKGROUND DATA

Biomechanical studies on the aforementioned and similar devices have been performed using synthetic, porcine, calf, or dog spines. As of the time of this writing, studies comparing anterior spinal implants using human cadaveric spines are scarce.

METHODS

An L1 corpectomy was performed on 19 spines. Stabilization was accomplished by an interbody wooden graft and the application of the Smooth Rod Kaneda in 10 spines and the Synthes Anterior Spinal Plate in the remaining 9. Biomechanical testing of the spines was performed in six degrees of freedom before and after stabilization, and after fatiguing to 5000 cycles of +/- 3 Nm of flexion and extension. Testing was repeated after uni- and bilateral facetectomy.

RESULTS

After stabilization, the Smooth Rod Kaneda was significantly more rigid than the anterior thoracolumbar bar spinal plate in extension. After fatigue, the Smooth Rod Kaneda was significantly stiffer than the anterior thoracolumbar spinal plate in flexion, extension, right lateral bending, left lateral bending, and right axial rotation. A significant decrease in stiffness was noted with the Synthes device in flexion after bilateral facetectomy compared with the stabilized spine.

CONCLUSIONS

The smooth Rod Kaneda device tends to be stiffer than the anterior thoracolumbar spinal plate, particularly in extension, exceeding the anterior thoracolumbar spinal plate in fatigue tolerance. The spine stabilized with the anterior thoracolumbar spinal plate is more susceptible to the destabilizing effect of bilateral facetectomy than than that stabilized with the Smooth Rod Kaneda. The additional rigidity encountered with the Smooth Rod Kaneda must be weighed against the simplicity of anterior thoracolumbar spinal plate application.

Interobserver variability in angiographic measurement and morphologic characterization of intracranial aneurysms: a report from the International Study of Unruptured Intracranial Aneurysms

PURPOSE

To determine the variability in assessment of the principal inherent characteristics of intracranial aneurysms through the evaluation of interobserver variability for material with uniform quality.

METHODS

Blinded interpretations of a single set of cerebral arteriograms of 55 aneurysms were evaluated by several statistical approaches.

RESULTS

Excellent correlations were found for the detection and measurement of aneurysms after adjusting for geometric distortion caused by magnification. Progressively decreasing correspondence was found for factors that characterized morphology, including, in order, determination of margins, assessment of accessory appendages, and identification of a neck.

DISCUSSION

Correction for geometric distortion was the most critical factor that influenced uniform measurement of size. Standards for measurement and morphologic characteristics were subsequently established for use in the International Study of Unruptured Intracranial Aneurysms.

Injuries among construction workers in rural Iowa: emergency department surveillance

Surveillance of all emergency department admissions for nine rural hospitals identified visits for injuries by 189 employed patients with construction occupations out of a total of 1843 injury visits of all employed patients with known occupations. The injury rate for construction workers was 20.28 injuries per 100 workers per year-more than 2.5 times that of all other employed people. The work-related injury rate was 7.63 per 100 construction workers, more than four times that of all other employed people. The injuries of construction workers seen in the emergency department were primarily open wounds, fractures and dislocations, and contusions, injuries similar to those of other workers. The percentage of work-related burns was higher in construction workers than for other workers, particularly because of burns to roofers and laborers from tar or hot fluids and flash burns from welding.

Iowa's National Laboratory for the study of Rural Telemedicine: a description of a work in progress

As the federal administration advances the idea of the "information superhighway," many disciplines are being challenged to find ways to use advanced telecommunications to improve access to information, enhance learning opportunities, and achieve higher levels of international competitiveness. Telemedicine, the use of communications technology in the practice of medicine, may change the way rural health care is provided by improving access to medical information, diagnostic tools, and consultations. The information and health care services required by health care professionals are rapidly changing, and dissemination of this information to isolated practitioners has proven to be difficult. By providing support electronically from a central site, the most current information is more readily available. Using test-bed hospitals in rural and urban settings, the National Library of Medicine-funded National Laboratory for the Study of Rural Telemedicine at the University of Iowa is currently developing the necessary infrastructure to support targeted projects studying how telemedicine applications can be made more effective and readily available.

Single fraction per day versus two fractions per day versus radiochemotherapy in the treatment of head and neck cancer

From January 1978 to January 1988, 859 patients with T3-T4, NO-3, MO were randomly allocated to receive either: Group A--60Co 60, 60 Gy in 30 fractions; Group B--60Co, 70.4 Gy in 64 fractions; Group C--60Co, 60 Gy in 30 fractions plus chemotherapy (5 Fu, 250 mg/m2/IV every 2 days). Chemotherapy and radiotherapy were combined simultaneously. The average age was 56 years; the male/female ratio was 802/57. Median performance status (ECOG scale) was 1 (range 0-2). The TNM distribution as UICC criteria was T3 529 patients; T4 330 patients; No 217 patients; N1 52 patients; N2 319 patients; and N3 271 patients. The primary sites were nasopharynx 92, oral cavity 252, hypopharynx 119, larynx 310, and others (sinuses and unknown primary)86. Complete response was achieved in 188/277 patients in Group A (67.8%), 254/282 patients in Group B (90%), and 289/300 in Group C (96.3%). All patients were followed and statistical analysis shows a significant improvement in median duration of response, as well as survival for Groups B and C compared with Group A. No significant differences were seen between Group B and C. The acute toxicity was mucositis, skin toxicity, bone marrow depression. A mean temporary weight loss of 4.9 Kg was observed with a range of 2.3-10.5 Kg.

Craniofacial trauma: an assessment of risk related to timing of surgery

Following the retrospective analysis of approximately 4000 head-injury patients, 49 were identified with a combination of displaced facial fractures and significant cerebral trauma. The purpose of this study was to define clinical and radiographic features in these patients that are associated with a poor prognosis, which in turn might influence the timing of facial fracture repair. The presence of an upper-level facial fracture, low Glasgow coma score, intracranial hemorrhage, displacement of normally midline cerebral structures, and multisystem trauma was associated with a statistically significant poorer prognosis. Additionally, in demographically similar groups of patients (age, sex, concomitant injury) preselected for intracranial pressures of less than 15 mmHg at the time of surgery, no significant difference in survival was appreciated in patients who underwent early (0 to 3 days), middle (4 to 7 days), or late (greater than 7 days) surgical repair. Early surgical repair of facial fractures in these circumstances does not appear to have a negative impact on recovery.

[Pulmonary tuberculosis: effectiveness and tolerance of a 6-month treatment schedule using 4 drugs]

255 patients diagnosed of pulmonary and/or pleural tuberculosis are prospectively studied. All patients received four drugs: isoniazine (INH), rifampin, pirazinamide and ethambutol during the first two months of treatment. Afterwards they continued for four months with two drugs in order to complete the six month treatment period. This schedule has been effective (0.7% of failures) in 99.3% of the patients. Two relapses were detected in the 229 patients who completed the two years follow up. 72 patients (28.2%) presented clinical secondary effects due to the treatment (40 cases of cutaneous affectation, 23 of gastrointestinal intolerance and 8 arthralgias respectively). Also, hyperuricemia was detected in 83% of the patients and a high transaminases level in 42.3%. In 13 patients treatment was cancelled or modified due to the secondary effects. In summary, this schedule of treatment has proved to be effective without an important frequency of serious secondary effects which can be objectively seen in the classical schedules of 9 months with 3 drugs (INH, RF, ET), nevertheless an increased frequency of minor secondary effects were detected.

Factors associated with hydrocephalus after subarachnoid hemorrhage. A report of the Cooperative Aneurysm Study

Hydrocephalus is an important complication of subarachnoid hemorrhage (SAH). We analyzed several factors possibly related to hydrocephalus following SAH in 3521 patients from the International Study on the Timing of Aneurysm Surgery. Hydrocephalus was diagnosed on admission computed tomographic (CT) scans in 15% of patients and was thought to be clinically symptomatic in 13.2% of patients. There was a 5.9% overlap between these groups. Using contingency table analysis, we found the following were significantly related to clinical hydrocephalus: increasing age; preexisting hypertension; admission blood pressure measurements; postoperative hypertension; admission CT findings of intraventricular hemorrhage, a diffuse collection of subarachnoid blood, and a thick focal collection of subarachnoid blood; posterior circulation site of aneurysm; focal ischemic deficits; use of antifibrinolytic drugs preoperatively; hyponatremia; admission level of consciousness; and a low score on the Glasgow outcome scale. Using discriminate factor analysis to predict clinical hydrocephalus, the most important variables in order were the following: CT hydrocephalus, intraventricular hemorrhage, admission level of consciousness, presubarachnoid hypertension, increasing age, subarachnoid blood noted on CT scan, posterior circulation aneurysm site, and hypertension postoperatively (canonical correlation = .399). We conclude that the development of hydrocephalus after SAH is multifactorial. Factors that compromise cerebrospinal fluid circulation acutely (eg, intraventricular hemorrhage, hemorrhage from a posterior circulation site of aneurysm, and diffuse spread of subarachnoid blood) contribute to the development of acute hydrocephalus. These same factors, plus the use of antifibrinolytic drugs preoperatively, are also important in the pathogenesis of clinical hydrocephalus, perhaps by promoting subarachnoid fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of aging and hypertension on endothelium-dependent vascular relaxation in rat carotid artery

We evaluated the effects of aging and hypertension on endothelium-dependent relaxation of rat common carotid arteries using 14-week-old (young) and 11-month-old (old) Wistar-Kyoto rats (WKY) and age-matched spontaneously hypertensive rats (SHR). Isometric tension of common carotid artery ring segments was measured. With a resting tension of 2.0 g determined from the baseline tension-contraction curves, precontraction was induced by 10(-5) M 5-hydroxytryptamine and endothelium-dependent relaxation was measured by application of either acetylcholine or adenosine 5'-triphosphate (ATP). Mean arterial blood pressure was 73.1 +/- 3.0 mm Hg in WKY and 110.0 +/- 3.1 mm Hg in SHR. These baseline values were significantly different. Acetylcholine-induced maximal relaxations were 70.1 +/- 2.6% of the 5-hydroxytryptamine-induced contraction in young WKY, 45.6 +/- 2.1% in old WKY, 35.1 +/- 1.8% in young SHR, and 21.4 +/- 2.5% in old SHR. On the other hand, ATP-induced relaxations were 52.0 +/- 3.2%, 35.7 +/- 3.8%, 21.7 +/- 3.5%, and 17.0 +/- 1.8% in the groups, respectively. Acetylcholine-induced relaxations were significantly different between WKY and SHR, young and old, independently. On the other hand, ATP-induced relaxations were also significantly different between young and old WKY, although no significant difference was observed between young and old SHR. The fact that endothelium-dependent relaxation of a cephalic artery is impaired in old rats and in hypertensive rats suggests that aging and hypertension are risk factors that may augment the disturbance of the cerebral circulation in pathologic conditions.