Is hip morphology a risk factor for developing hip osteoarthritis? A systematic review with meta-analysis.

OBJECTIVE: To appraise the highest evidence on hip morphology as a risk factor for developing hip osteoarthritis (OA). DESIGN: We searched for studies evaluating the association between radiological hip morphology parameters and the prevalence, incidence or progression of hip OA (based on different radiographic and clinical criteria) in the MEDLINE, EMBASE, Web of Science, Scopus, Cochrane Library and PEDro databases from inception until June 2020. Prospective and cross-sectional studies were separately evaluated. Data are presented as odds ratios (OR) with 95% confidence intervals (CI). RESULTS: We included 9 prospective and 21 cross-sectional studies in the meta-analysis, and evaluated 42,831 hips from 25,898 individuals (mean age: 59 years). Prospective studies showed that, compared with control hips, hips with cam morphology (alpha angle >60°; OR = 2.52, 95% CI: 1.83 to 3.46, P < 0.001) or hip dysplasia (lateral center-edge angle (LCEA) <25°; OR = 2.38, 95% CI: 1.84 to 3.07, P < 0.001), but not hips with pincer morphology (LCEA >39°; OR = 1.08, 95% CI: 0.57 to 2.07, P = 0.810), were more likely to develop hip OA than hips without these morphologies. Cross-sectional studies showed a greater prevalence of pincer morphology (LCEA >39°, OR = 3.71, 95% CI: 2.98 to 4.61, P < 0.001) and acetabular retroversion (crossover sign; OR = 2.65, 95% CI: 1.17 to 6.03, P = 0.020) in hips with OA than in control hips. CONCLUSION: Cam morphology and hip dysplasia were consistently associated with the development of hip OA. Pincer morphology was associated with hip OA in cross-sectional but not in prospective studies. The heterogeneous quantification of pincer morphology on radiographs limits a clear conclusion on its association with hip OA.

Statistical shape modeling of the hip and the association with hip osteoarthritis: a systematic review.

OBJECTIVE: To summarize available evidence on the association between hip shape as quantified by statistical shape modeling (SSM) and the incidence or progression of hip osteoarthritis. DESIGN: We conducted a systematic search of five electronic databases, based on a registered protocol (available: PROSPERO CRD42020145411). Articles presenting original data on the longitudinal relationship between radiographic hip shape (quantified by SSM) and hip OA were eligible. Quantitative meta-analysis was precluded because of the use of different SSM models across studies. We used the Newcastle-Ottawa Scale (NOS) for risk of bias assessment. RESULTS: Nine studies (6,483 hips analyzed with SSM) were included in this review. The SSM models used to describe hip shape ranged from 16 points on the femoral head to 85 points on the proximal femur and hemipelvis. Multiple hip shape features and combinations thereof were associated with incident or progressive hip OA. Shape variants that seemed to be consistently associated with hip OA across studies were acetabular dysplasia, cam morphology, and deviations in acetabular version (either excessive anteversion or retroversion). CONCLUSIONS: Various radiographic, SSM-defined hip shape features are associated with hip OA. Some hip shape features only seem to increase the risk for hip OA when combined together. The heterogeneity of the used SSM models across studies precludes the estimation of pooled effect sizes. Further studies using the same SSM model and definition of hip OA are needed to allow for the comparison of outcomes across studies, and to validate the found associations.

Metabolic osteoarthritis - relation of diabetes and cardiovascular disease with knee osteoarthritis.

OBJECTIVE: There is an interest in identifying a metabolic OA phenotype. We therefore assessed the relation of diabetes and cardiovascular disease to prevalent and incident radiographic (ROA) and symptomatic knee osteoarthritis (SxOA). DESIGN: In two large cohort studies of individuals with or at risk for knee OA, the Multicenter Osteoarthritis Study (MOST) and Osteoarthritis Initiative (OAI), participants self-reported diabetes and cardiovascular disease (CVD) at baseline. We assessed the relation of baseline diabetes and CVD (exposures) to ROA and SxOA cross-sectionally and after 60 (MOST) or 48 (OAI) months of follow-up using logistic regression with GEE to account for 2 knees within an individual, adjusting for potential confounders. RESULTS: In MOST, 6,020 knees of 3,021 participants (60.1% female, mean ± SD age 62.5 ± 8.1, mean BMI 30.7 ± 6.0, 83.3% Caucasian) were included in the analyses. In OAI, 8,645 knees of 4,339 participants (58.2% female, mean ± SD age 61.1 ± 9.2, mean BMI 28.6 ± 4.8, 80.3% Caucasian) were included. We found no significant associations between prevalent diabetes or CVD and prevalent or incident ROA or SxOA. Effect estimates for prevalent ROA and SxOA ranged from 0.80 (95% CI 0.63-1.03) to 1.17 (0.91-1.51). Effect estimates for incident ROA ranged from 0.80 (0.58-1.11) to 0.88 (0.60-1.29) in MOST and from 0.75 (0.50-1.14) to 1.19 (0.81-1.74) in OAI, and for incident SxOA from 0.93 (0.65-1.31) to 1.22 (0.89-1.67) in MOST and from 0.82 (0.59-1.16) to 1.19 (0.85-1.66) in OAI). CONCLUSIONS: Diabetes and CVD were not associated with prevalent or incident knee OA.

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.

Longitudinal analysis of cartilage T2 relaxation times and joint degeneration in African American and Caucasian American women over an observation period of 6 years - data from the Osteoarthritis Initiative.

OBJECTIVES: To investigate the change in cartilage T2 values and structural degeneration in knee joints over 72 months in women of African American (AA) vs Caucasian American (CA) ethnicity. METHODS: Knee 3T magnetic resonance imaging (MRIs) from baseline, 24, 48 and 72 months visits of 100 AA and 100 CA women from the Osteoarthritis Initiative (OAI) were assessed for cartilage T2 values and whole-organ magnetic resonance imaging (WORMS) score. Subjects were pair-matched by age, body mass index (BMI), Kellgren-Lawrence (KL) score, clinical site and subcohort within the OAI. We compared the rate of change in whole knee cartilage T2 values and WORMS cartilage, bone marrow edema pattern (BMEP) and meniscus scores between the two ethnic groups using mixed random effects models. RESULTS: At 24 and 48 months 60 subjects and at 72 months 45 subjects per group were available for analysis resulting in 38 complete pairs with data of all time points. Compared to CA, cartilage T2 values in AA increased at a significantly faster rate at baseline (AA: 0.45 ms/y, CA: 0.35 ms/y, P = 0.029) and averaged over 6 years (AA: 0.36 ms/y, CA: 0.27 ms/y, P = 0.039) with changes in both groups reaching a plateau by 48 months. Cartilage, meniscus and BMEP scores tended to increase in both groups during follow up, but rates of change did not differ by ethnicity. CONCLUSION: Cartilage T2 values increased faster over 72 months in AA than CA, however changes in WORMS cartilage, meniscus and BMEP scores did not differ. T2 values may be able to distinguish ethnicity-related differences of cartilage degeneration at an early stage before differences in structural joint degeneration appear.

Progression of cartilage degeneration and clinical symptoms in obese and overweight individuals is dependent on the amount of weight loss: 48-month data from the Osteoarthritis Initiative.

OBJECTIVE: To investigate compositional cartilage changes measured with 3T MRI-based T2 values over 48 months in overweight and obese individuals with different degrees of weight loss (WL) and to study whether WL slows knee cartilage degeneration and symptom worsening. DESIGN: We studied participants from the Osteoarthritis Initiative with risk factors or radiographic evidence of mild to moderate knee osteoarthritis with a baseline BMI ≥25 kg/m(2). We selected subjects who over 48 months lost a, moderate (BMI change, 5-10%WL, n = 180) or large amount of weight (≥10%WL, n = 78) and frequency-matched these to individuals with stable weight (<3%, n = 258). Right knee cartilage T2 maps of all compartments and grey-level co-occurrence matrix (GLCM) texture analyses were evaluated and associations with WL and clinical symptoms (WOMAC subscales for pain, stiffness and disability) were assessed using multivariable regression models. RESULTS: The amount of weight change was significantly associated with change in cartilage T2 of the medial tibia (ß 0.9 ms, 95% CI 0.4 to 1.1, P = 0.001). Increase of T2 in the medial tibia was significantly associated with increase in WOMAC pain (ß 0.5 ms, 95% CI 0.2 to 0.6, P = 0.02) and disability (ß 0.03 ms, 95% CI 0.003 to 0.05, P = 0.03). GLCM contrast and variance over all compartments showed significantly less progression in the >10%WL group compared to the stable weight group (both comparisons, P = 0.04). CONCLUSIONS: WL over 48 months is associated with slowed knee cartilage degeneration and improved knee symptoms.

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.

Severe radiographic knee osteoarthritis--does Kellgren and Lawrence grade 4 represent end stage disease?--the MOST study.

OBJECTIVE: To determine what MRI-detectable osteoarthritis features that are not visualized on radiography demonstrate progression longitudinally in Kellgren and Lawrence (KL) grade 4 knees. METHODS: We studied subjects from the Multicenter Osteoarthritis Study who had KL grade 4 knees at baseline and had baseline and 30-month MRI. Cartilage damage, bone marrow lesions (BMLs), meniscal damage, synovitis (signal changes in Hoffa fat pad), and effusion (fluid equivalent signal in the joint cavity) were semiquantitatively scored using the Whole Organ MRI Score (WORMS) system in five subregions of the medial and lateral tibiofemoral (TF) compartments. Analysis was performed for the compartment showing bone-on-bone appearance ("index") on radiograph and also for the other TF compartment of the same knee. Synovitis and effusion were assessed for the whole knee. Changes in scores at follow-up were noted for each feature. For cartilage and BML, within-grade changes were also recorded. RESULTS: 140 subjects (164 knees) were included (50% women, mean age 66.0 ± 8.6 years, mean BMI 30.4 ± 5.1 kg/m(2)). Longitudinally, 51 index compartments (34%) showed an increase in the sum of cartilage scores from all subregions. In the other compartment, 25% showed an increase in the sum score for cartilage damage. For BMLs in the index compartment, 50 knees (33%) showed an increase in maximum score and 32 (21%) showed a decrease. Meniscal status mostly remained stable. Effusion worsened in 36 knees (25%) and improved in 13 knees (9%). Synovitis worsened in 14 knees (10%) and improved in six knees (4%). CONCLUSION: In KL grade 4 knees, MRI-detected cartilage loss and fluctuation of BMLs, effusion, and synovitis occurred frequently over a 30-month period.

Association of Physical Activity Measured by Accelerometer, Knee Joint Abnormalities, and Cartilage T2 Measurements Obtained From 3T Magnetic Resonance Imaging: Data From the Osteoarthritis Initiative.

OBJECTIVE: To study the cross-sectional association between physical activity measured with an accelerometer, structural knee abnormalities, and cartilage T2 values assessed with 3T magnetic resonance imaging (MRI). METHODS: We included 274 subjects from the Osteoarthritis Initiative cohort without definite radiographic osteoarthritis (Kellgren/Lawrence grades 0 and 1) and with at most mild pain, stiffness, and functional limitation in the study knee (Western Ontario and McMaster Universities Osteoarthritis Index scale 0-1), which had not limited their activity due to knee pain. Physical activity was measured over 7 days with an ActiGraph GT1M accelerometer. Subjects were categorized by quartile of physical activity based on the average daily minutes of moderate to vigorous physical activity (mv-PA). MRI images of the right knee (at 48-month visit) were assessed for structural abnormalities using a modified Whole-Organ Magnetic Resonance Imaging Score (WORMS) and for T2 relaxation times derived from segmented cartilage of 4 femorotibial regions and the patella. WORMS grades and T2 measurements were compared between activity quartiles using a linear regression model. Covariates included age, sex, body mass index, knee injury, family history of knee replacement, knee symptoms, hip and ankle pain, and daily wear time of the accelerometer. RESULTS: Higher mv-PA was associated with increased severity (P = 0.0087) and number of lesions of the medial meniscus (P = 0.0089) and with severity of bone marrow edema lesions (P = 0.0053). No association between cartilage lesions and mv-PA was found. T2 values of cartilage (loss, damage, and abnormalities) tended to be greater in the higher quartiles of mv-PA, but the differences were nonsignificant. CONCLUSION: In knees without radiographic osteoarthritis in subjects with no or mild knee pain, higher physical activity levels were associated with increases in meniscal and bone marrow edema pattern lesions.

Association of cartilage degeneration with four year weight gain--3T MRI data from the Osteoarthritis Initiative.

OBJECTIVE: To determine the effect of weight gain on progression of early knee morphologic abnormalities using magnetic resonance imaging (MRI) in a longitudinal study over 48 months. DESIGN: We studied the right knee of 100 subjects from the Osteoarthritis Initiative (OAI), selecting subjects aged ≥ 45 with osteoarthritis (OA) risk factors who demonstrated weight gain (minimum 5% increase in body mass index, BMI, n = 50) or no change in weight (BMI change < 2%, n = 50), frequency matched for age, gender, and baseline BMI. Baseline and 48 month knee MRI studies were scored for lesions using a modified whole organ MRI score (WORMS). Logistic regression models were used to compare the differences between the two groups. RESULTS: The odds of worsening maximum cartilage (11.3, 95%, CI 3.5-51.4) and meniscal WORMS (4.5, 95% CI 1.4-17.3) were significantly greater in the weight gain group compared to the no change group, in addition to the odds of worsening cartilage defects at the patella and average meniscal WORMS (P < 0.05). Odds of worsening average bone marrow edema pattern (BMEP) were significantly greater for the weight gain group compared to the no change cohort (P < 0.05). CONCLUSION: Our study demonstrated that weight gain is strongly associated with increased progression of cartilage degeneration in middle-aged individuals with risk factors for OA.

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.

The relationship between quadriceps muscle weakness and worsening of knee pain in the MOST cohort: a 5-year longitudinal study.

OBJECTIVE: To determine whether quadriceps weakness is associated with elevated risk of worsening knee pain over 5 years. METHODS: The Multicenter Osteoarthritis Study (MOST) is a longitudinal study of 50-79-year-old adults with knee osteoarthritis (OA) or known risk factors for knee OA. The predictor variable was baseline isokinetic quadriceps strength. Covariates included baseline body mass index (BMI), physical activity level, and history of knee surgery. The outcome was worsening pain reported on the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index pain subscale or knee replacement surgery between baseline and 5-year follow-up. Analyses were knee-based and used generalized estimating equations, stratified by sex to assess whether the lowest compared with the highest tertile of baseline quadriceps strength was associated with an increased risk of worsening knee pain at 5-year follow-up, controlling for age, BMI, history of knee surgery, and physical activity level as well as correlation between knees within participants. RESULTS: Analyses of worsening knee pain included 4,648 knees from 2,404 participants (61% female). Men with lower quadriceps strength did not have a higher risk of worsening knee pain (RR {95% CI} = 1.01 {0.78-1.32}, P = 0.9183). However, women in the lowest compared with the highest strength tertile had a 28% increased risk of worsening knee pain (RR {95% CI} = 1.28 {1.08-1.52}, P = 0.0052). CONCLUSION: Quadriceps weakness was associated with an increased risk of worsening of knee pain over 5 years in women, but not in men.

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.

The longitudinal relationship between thigh muscle mass and the development of knee osteoarthritis.

OBJECTIVE: Greater quadriceps strength has been found to reduce risk for symptomatic knee osteoarthritis (SxKOA) and knee joint space narrowing (JSN). However, this finding could relate to muscle mass or activation pattern. The purpose of this study was to assess whether greater thigh muscle mass protects against (1) incident radiographic (RKOA), (2) incident SxKOA or (3) worsening of knee JSN by 30-month follow-up. DESIGN: Multicenter Osteoarthritis (MOST) study participants, who underwent dual-energy X-ray absorptiometry (DXA) at the Iowa site were included. Thigh muscle mass was calculated from DXA image sub-regions. Sex-stratified, knee-based analyses controlled for incomplete independence between limbs within subjects. The effect of thigh lean mass and specific strength as predictors of ipsilateral RKOA, SxKOA and worsening of JSN were assessed, while controlling for age, body mass index (BMI), and history of knee surgery. RESULTS: A total of 519 men (948 knees) and 784 women (1453 knees) were included. Mean age and BMI were 62 years and 30 kg/m(2). Thigh muscle mass was not associated with risk for RKOA, SxKOA or knee JSN. However, in comparison with the lowest tertile, those in the highest and middle tertiles of knee extensor specific strength had a lower risk for SxKOA and JSN [odds ratio (OR) 0.29-0.68]. CONCLUSIONS: Thigh muscle mass does not appear to confer protection against incident or worsening knee OA. These findings suggest that future studies of risk for knee OA should focus on the roles of knee extensor neuromuscular activation and muscle physiology, rather than the muscle mass.

Predictive validity of within-grade scoring of longitudinal changes of MRI-based cartilage morphology and bone marrow lesion assessment in the tibio-femoral joint--the MOST study.

OBJECTIVE: In order to increase sensitivity to detect longitudinal change, recording of within-grade changes was introduced for cartilage morphology and bone marrow lesion (BML) assessment in semiquantitative magnetic resonance imaging (MRI) scoring of knee osteoarthritis (OA). The aim of this study was to examine the validity provided by within-grade scoring. DESIGN: The Multicenter Osteoarthritis (MOST) study is a longitudinal study of subjects with or at risk of knee OA. Baseline and 30 months MRIs were read according to the modified Whole-Organ Magnetic Resonance Imaging Score (WORMS) system including within-grade changes for cartilage and BMLs. We tested the validity of within-grade changes by whether the 30-month changes in cartilage and BML assessment were predicted by baseline ipsi-compartmental meniscal damage and malalignment, factors known to affect cartilage loss and BMLs, using ordinal logistic regression. RESULTS: 1867 Knees (from 1411 participants) were included. Severe medial meniscal damage predicted partial grade (adjusted odds ratio (aOR) 4.4, 95% confidence interval (95% CI) 2.2, 8.7) but not ≥full grade (aOR 1.3, 95% CI 0.8, 2.2) worsening of cartilage loss and predicted both, partial grade (aOR 9.6, 95% CI 3.6, 25.1) and ≥full grade (aOR 5.1, 95% CI 3.2, 8.2) worsening of BMLs. Severe, but not moderate, malalignment predicted ipsi-compartmental within-grade (medial cartilage damage: aOR 5.5, 95% CI 2.6, 11.6; medial worsening of BMLs: aOR 4.9, 95% CI 2.0, 12.3) but not full grade worsening of BMLs and cartilage damage. CONCLUSIONS: Within-grade changes in semiquantitative MRI assessment of cartilage and BMLs are valid and their use may increase the sensitivity of semiquantitative readings in detecting longitudinal changes in these structures.

Knee malalignment is associated with an increased risk for incident and enlarging bone marrow lesions in the more loaded compartments: the MOST study.

OBJECTIVE: To examine the relationship of knee malalignment with occurrence of incident and enlarging bone marrow lesions (BMLs) and regression of BMLs. METHODS: Subjects from the Multicenter Osteoarthritis Study aged 50-79 years with or at high risk of knee osteoarthritis were studied. Full-limb radiographs were taken at baseline and hip-knee-ankle mechanical axis was measured. Baseline and 30-month magnetic resonance imaging (MRI) of knees (n = 1782) were semiquantitatively assessed for BMLs. Outcome was defined as a change in BML score in femoral/tibial condyle in medial/lateral compartments. Medial compartment in varus alignment and lateral compartment in valgus alignment were combined to form 'more loaded' compartment, while lateral compartment in valgus and medial compartment in varus were combined to form 'less loaded' compartment. Relative risk (RR) of BML score increase or decrease in relation to malalignment was estimated using a log linear regression model with the Poisson assumption, adjusting for age, gender, body mass index, physical activity scale for the elderly, race and clinic site. Further, results were stratified by ipsilateral meniscal and cartilage status at baseline. RESULTS: Baseline varus alignment was associated with higher risk of BML score increase from baseline to follow-up in the medial compartment [adjusted RRs (95%CI): 1.5 (1.2-1.9)] and valgus alignment in the lateral compartment [1.4 (1.0-2.1)]. Increase in BML score was more likely in the more loaded compartments [1.7 (1.4-2.0)] in malaligned knees. Regardless of ipsilateral cartilage or meniscus status, adjusted RR for BML score increase was higher in the more loaded compartments of malaligned knees than those with neutral alignment. Decrease in BML score was less likely in the more loaded compartments in malaligned knees [0.8 (0.7-1.0)]. CONCLUSION: Knee malalignment is associated with increased risk of incident and enlarging BMLs in the more loaded compartments of the tibiofemoral joint.

Baseline mean and heterogeneity of MR cartilage T2 are associated with morphologic degeneration of cartilage, meniscus, and bone marrow over 3 years--data from the Osteoarthritis Initiative.

OBJECTIVE: The purpose of this study is to determine whether the mean and heterogeneity of magnetic resonance (MR) knee cartilage T(2) relaxation time measurements at baseline are associated with morphologic degeneration of cartilage, meniscus, and bone marrow tissues over 3 years in subjects with risk factors for osteoarthritis (OA). DESIGN: Subjects with risk factors for OA (n=289) with an age range of 45-55 years were selected from the Osteoarthritis Initiative (OAI) database. 3.0 Tesla MR images were analyzed using morphological gradings of cartilage, bone marrow and menisci whole-organ magnetic resonance imaging scores (WORMS scoring). A T(2) mapping sequence was used to assess the mean and heterogeneity of cartilage T(2) (gray level co-occurrence matrix texture analysis). Regression models were used to assess the relationship between baseline T(2) parameters and changes in morphologic knee WORMS scores over 3 years. RESULTS: The prevalence of knee abnormalities in the cartilage (P<0.0005), meniscus (P<0.00001), and bone marrow significantly (P<0.00001) increased from baseline to 3 years in all compartments combined. The baseline mean and heterogeneity of cartilage T(2) were significantly (P<0.05) associated with morphologic joint degeneration in the cartilage, meniscus and bone marrow over 3 years. CONCLUSIONS: The prevalence of knee abnormalities significantly increased over 3 years; increased cartilage T(2) at baseline predicted longitudinal morphologic degeneration in the cartilage, meniscus, and bone marrow over 3 years in subjects with risk factors for OA.

Cyst-like lesions of the knee joint and their relation to incident knee pain and development of radiographic osteoarthritis: the MOST study.

OBJECTIVE: To determine whether intra- and periarticular cyst-like lesions of the knee are associated with incident knee pain and incident radiographic knee osteoarthritis (OA). DESIGN: The Multicenter Osteoarthritis (MOST) Study is a cohort of individuals who have or are at high risk for knee OA. Using a nested case-control study design, we investigated the associations of cyst-like lesions (Baker's, meniscal and proximal tibiofibular joint (PTFJ) cysts, and prepatellar and anserine bursitides) with (1) incident pain at 15- or 30-month follow-up and (2) incident radiographic OA at 30-month follow-up. Baseline cyst-like lesions were scored semiquantitatively using the Whole Organ Magnetic Resonance Imaging Score (WORMS). Conditional logistic regression models were used to assess the relation between these lesions and the outcomes, adjusting for potential confounding factors (i.e., cartilage loss, meniscal damage, bone marrow lesions, synovitis and joint effusion, which were also scored using WORMS). RESULTS: Incident knee pain study included 157 cases and 336 controls. Prevalence of meniscal and PTFJ cysts in the case group was twice that in the control group [9 (6%) vs 9 (3%) and 9 (6%) vs 10 (3%), respectively]. Incident radiographic OA study included 149 cases and 298 controls. Prevalence of grade 2 Baker's cysts and PTFJ cysts in the case group was approximately four times that in the control group [16(11%) vs 9 (3%) and 6 (4%) vs 3 (1%), respectively]. However, none of the cyst-like lesions was associated with incident pain or radiographic OA after fully adjusted logistic regression analyses and correction of P-values for multiple comparisons. CONCLUSION: None of the analyzed lesions was an independent predictor of incident knee pain or radiographic OA. Intra- and periarticular cyst-like lesions are likely to be a secondary phenomenon seen in painful or OA-affected knees, rather than a primary trigger for incident knee pain or radiographic OA.

Comparison of BLOKS and WORMS scoring systems part I. Cross sectional comparison of methods to assess cartilage morphology, meniscal damage and bone marrow lesions on knee MRI: data from the osteoarthritis initiative.

OBJECTIVE: To compare two semiquantitative scoring systems for assessing the prevalence and severity of morphologic cartilage lesions, meniscal damage and bone marrow lesions (BMLs) from Magnetic Resonance Imagings (MRIs) of knees with osteoarthritis (OA). METHODS: From participants in the OA Initiative (OAI), a sample of 115 knees with radiographic OA at high risk of cartilage loss, were selected based on risk factors for progression. Knee MRIs were read separately using both Whole Organ MR Scoring (WORMS) and Boston-Leeds OA Knee Scoring (BLOKS), and a subset was fed back to readers for reliability. Baseline readings were used for comparison of the two methods for inter-reader reliability as well as agreement on presence/absence and severity of MRI features at both the compartment level and finer anatomical subregion levels. RESULTS: Both methods had high inter-reader agreement for all features studied (kappa for WORMS 0.69-1.0 and for BLOKS 0.65-1.0). Although the methods agreed well on presence and severity of morphological cartilage lesions (inter-method kappas from 0.66 to 0.95), BLOKS was more sensitive for full thickness defects. The two methods gave equivalent results for extent (kappa 0.74-0.80) and number (Spearman's Rho=0.85) of BMLs, and little extra information was obtained using the more complex BLOKS BML scoring. Similar results were also obtained for the common types of meniscal damage and extrusion (inter-method kappa 0.85-0.94), but the inclusion in BLOKS of meniscal signal abnormality and uncommon types of tear may be an advantage if these prove clinically meaningful. CONCLUSION: Both WORMS and BLOKS had high reliability. The two methods gave similar results in this sample for prevalence and severity of cartilage loss, BMLs and meniscal damage. Selecting between, or combining, the two methods should be based on factors such as reader effort, appropriateness for the goals of a study, and longitudinal performance.