Thigh Muscle Cross-Sectional Areas and Strength in Advanced versus Early Painful Osteoarthritis – an Exploratory Between-Knee, Within-Person Comparison in Osteoarthritis Initiative Participants

OBJECTIVE: To compare cross-sectional and longitudinal side differences in thigh muscle anatomic cross-sectional areas (ACSAs), strength, and specific strength (strength/ACSA) between knees with early versus advanced painful radiographic osteoarthritis in the same person. METHODS: Forty-four of 2,678 Osteoarthritis Initiative participants (31 women and 13 men) met the inclusion criteria of bilateral frequent knee pain, medial joint space narrowing (JSN) in 1 knee, and no medial (or lateral) JSN in the contralateral knee. Thigh muscle ACSAs of the quadriceps, hamstrings, adductors, and individual quadriceps heads at consistent locations were determined using magnetic resonance imaging. Isometric muscle strength was determined in extension/flexion (Good Strength Chair). Baseline quadriceps ACSAs and strength were considered primary end points, and longitudinal changes of these factors were considered secondary end points (by paired t-tests). RESULTS: No significant side differences in quadriceps (or other thigh muscle) ACSAs, strength, or specific strength were observed between medial JSN knees versus knees without JSN, or between specific medial JSN knee strata and contralateral knees without JSN, either in men or women. Two-year longitudinal changes in thigh muscle ACSAs and strength were small (<5.2%) and did not differ significantly between medial JSN knees and knees without JSN. CONCLUSION: In the context of previous findings that side differences in pain are associated with side differences in quadriceps ACSAs, the current results suggest that quadriceps (and other thigh muscle) properties are not independently associated with radiographic disease status (JSN) once knees have reached frequent pain status. Further, our longitudinal findings indicate that a more advanced radiographic stage of knee osteoarthritis is not necessarily associated with a longitudinal decline in muscle function. Copyright 2013 by the American College of Rheumatolog

Evaluation of bone marrow lesion volume as a knee osteoarthritis biomarker - longitudinal relationships with pain and structural changes: data from the Osteoarthritis Initiative

Abstract Introduction Bone marrow lesion (BML) size may be an important imaging biomarker for osteoarthritis-related clinical trials and reducing BML size may be an important therapeutic goal. However, data on the interrelationships between BML size, pain, and structural progression are inconsistent and rarely examined in the same cohort. Therefore, we evaluated the cross-sectional and longitudinal associations of BML volume with knee pain and joint space narrowing (JSN). Methods A BML volume assessment was performed on magnetic resonance images of the knee collected at the 24- and 48-month Osteoarthritis Initiative visits from a convenience sample of 404 participants in the progression cohort. During the same visits, knee pain was assessed with WOMAC pain scores and knee radiographs were acquired and scored for JSN. BML volume was summed to generate a total knee volume and an index tibiofemoral compartment volume (compartment with greater baseline JSN). Primary analyses included multiple linear regressions (outcome = pain, predictor = total knee BML volume) and logistic regressions (outcome = JSN, predictor = index tibiofemoral compartment BML volume). Results This sample was 49% female with a mean age of 63 (9.2 standard deviation (SD)) years, and 71% had radiographic osteoarthritis in the study knee. Larger baseline BMLs were associated with greater baseline knee pain (P = 0.01), the presence of JSN at baseline (odds ratio (OR) = 1.50, 95% confidence interval (CI) = 1.23 to 1.83), and JSN progression (OR = 1.27, 95%CI = 1.11 to 1.46). Changes in total knee BML volume had a positive association with changes in knee pain severity (P = 0.004) and this association may be driven by knees that were progressing from no or small baseline BMLs to larger BMLs. In contrast, we found no linear positive relationship between BML volume change and JSN progression. Instead, regression of medial tibiofemoral BML volume was associated with JSN progression compared to knees with no or minimal changes in BML volume (OR = 3.36, 95%CI = 1.55 to 7.28). However, follow-up analyses indicated that the association between JSN progression and BML volume change may primarily be influenced by baseline BML volume. Conclusion Large baseline BMLs are associated with greater baseline knee pain, the presence of JSN at baseline, and disease progression. Additionally, BML regression is associated with decreased knee pain but not a reduced risk of concurrent JSN progression

Radiographic joint space narrowing in osteoarthritis of the knee: relationship to meniscal tears and duration of pain

[[abstract]]Objective The objective of this study was to assess, with knee radiography, joint space narrowing (JSN) and its relationship to meniscal tears, anterior cruciate ligament (ACL) ruptures, articular cartilage erosion, and duration of pain in patients with knee osteoarthritis. Materials and methods A total of 140 patients who had knee osteoarthritis and underwent primary total knee replacement (TKR) surgery, with unicompartmental medial tibiofemoral JSN (grade 1 or greater) and normal lateral compartments, were recruited. Polytomous logistic regression was used to assess the relationship between JSN and risk factors. Results All patients with JSN were categorized as grade 1 (n = 14, 10.0%), grade 2 (n = 64, 45.7%), or grade 3 (n = 62, 44.3%). Women presented with indications for a TKR at a younger age than men (mean age, 69 vs 73 years, P < 0.05). There were 123 (87.9%) meniscal tears and 58 (41.4%) partial (insufficient or attenuated ACL fibers) and 10 (7.1%) complete ACL ruptures; 115 of 134 (85.8%) patients had moderate to severe cartilage erosion. A higher grade of JSN was correlated with a higher frequency of meniscal tears [odds ratio (OR) 6.00, 95% CI 1.29–27.96 for grade 2 vs grade 1 JSN] and duration of knee pain (OR 1.25, 95% CI 1.01–1.53 for grade 3 vs grade 1 JSN). A higher grade of JSN was not correlated with a higher frequency of ACL rupture or articular cartilage erosion. Conclusion A higher grade of JSN is associated with a higher frequency of meniscal tears and long duration of knee pain in patients with knee osteoarthritis.[[incitationindex]]SCI[[booktype]]紙

Alignment of the medial tibial plateau affects the rate of joint space narrowing in the osteoarthritic knee

SummaryObjectiveTo determine, in serial fixed-flexion (FF) radiographs of subjects with knee osteoarthritis (KOA), the importance of, and basis for, the effect of alignment of the medial tibial plateau (MTP), as determined by the inter-margin distance (IMD), on joint space narrowing (JSN).MethodsBaseline and 12-month X-rays of 590 knees with Kellgren and Lawrence grade (KLG) 2/3 OA from the public-release dataset of the Osteoarthritis Initiative (OAI) were assigned to subgroups based upon IMD at baseline (IMDBL) and the difference between IMDBL and IMD12mos. Relationships of JSN to IMDBL and to the difference between IMDBL and IMD12mos were evaluated.ResultsIn all 590 knees, mean JSN was 0.13±0.51mm (P<0.0001) and MTP alignment and replication of IMDBL in the 12-month film were, in general, poor. JSN was significantly (P=0.012) more rapid in Subgroup A (IMD≤1.70mm at both time points) than in Subgroup B (both IMDs>1.70mm): 0.15±0.43; 0.08±0.47. Within Subgroup B we identified a subset, Subgroup B1, in which, although alignment was poor at both time points, the large IMDBL was, by chance, highly reproduced by IMD12mos (difference between the two IMDs=0.01±0.27mm, NS). JSN in Subgroup B1 was 0.06±0.41mm and did not differ from that in other knees of Subgroup B (P=0.87). The standardized response mean (SRM) in all 590 knees and Subgroups A, B and B1 was 0.25, 0.34, 0.17 and 0.06, respectively. Independent of IMDBL, JSN correlated significantly with the difference between the IMDs in the two radiographs (r=0.17, P=0.0001).ConclusionSkewed MTP alignment in serial films and poor replication of IMDBL in the follow-up exam affect JSN measurement. The magnitude of change in joint space width (JSW) related to the poor quality of alignment that is common with the FF view jeopardizes accurate evaluation of JSN

395 OSTEOPHYTES AND JOINT SPACE NARROWING ARE INDEPENDENTLY ASSOCIATED WITH PAIN IN FINGER JOINTS IN HAND OSTEOARTHRITIS

Objective To study the associations between structural abnormalities on ultrasound (US) or conventional x-rays (CR) and pain in hand osteoarthritis (HOA). Methods In 55 consecutive patients with HOA (mean age 61 years, 86% women) fulfilling the American College of Rheumatology criteria, pain in 30 separate hand joints was assessed upon palpation; osteophytes were assessed by US and CR and joint space narrowing (JSN) by CR. Associations between structural abnormalities and pain per joint were analysed using generalised estimated equations to account for patient effects and adjusted for age, sex, body mass index, US inflammatory features and other remaining structural abnormalities. Results In 1649 joints, 69% and 46% had osteophytes on US and CR, respectively and 47% had JSN. Osteophytes and JSN showed independent associations with pain per joint adjusted: OR for osteophytes: 4.8 (95% CI 3.1 to 7.5) for US and 4.1 (95% CI 2.4 to 7.1) for CR; for JSN: 4.2 (95% CI 2.0 to 9.0). Conclusions Osteophytes and JSN are independently associated with pain in individual HOA joints, taking into account patient effects

Age affects joint space narrowing in patients with early active rheumatoid arthritis

Background: Joint space narrowing ( JSN) in rheumatoid arthritis (RA) may be a manifestation of (primary) osteoarthritis becoming more prominent with age. We investigated the severity and predictors of JSN progression among different age groups. Methods: 10-year follow-up data of the BeSt study, a randomised controlled treat-to-target trial in early RA were used. Annual X-rays of hands and feet were scored using the Sharp/van der Heijde score (SHS). Subgroups were defined by age at baseline: 55, 40<55 and <40 years. JSN progression predictors were assessed by Poisson regression. Results: Baseline JSN scores (median (IQR)) were igher in patients 55 (2.0 (0.0-6.0)) compared with the other age groups: 1.0 (0.0-3.0) 40<55 and 0.3 (0.0-3.0) <40, p<0.001. After 10 years, total JSN and SHS were similar in all age groups. In patients 55 the mean erythrocyte sedimentation rate (ESR) over time (relative risk 1.02 (95% CI 1.00 to 1.03)

Rates of medial tibiofemoral joint space narrowing in osteoarthritis studies consistent despite methodological differences

SummaryRationaleMinimum tibiofemoral joint space width in the medial compartment (JSW) is the most well-established structural outcome measure for osteoarthritis (OA) of the knee. Its usefulness as a measure of therapeutic effectiveness in short-term studies is limited by the rate and variability of joint space narrowing (JSN) in the OA population. Microfocal radiography has been shown to improve reproducibility of JSW measurement compared to standard radiography, but measurement of magnification from microfocal knee films has been problematic, and JSN is yet to be investigated in a longitudinal microfocal study.ObjectiveTo establish the effect on JSW reproducibility of a new method of magnification measurement in microfocal radiographs. To report on and compare rates of medial tibiofemoral JSN and their variations in the placebo arms of microfocal and standard radiographic clinical trials in OA, using fluoroscopic semi-flexed (SF) knee positioning. To place in the context of published estimates of rates of JSN from comparable studies.MethodsUsing microfocal radiography, 36 patients were followed at a single centre for 2 years. Using standard radiography, 86 patients were followed for 1 year at a single centre, and 549 for 2 years in a multi-centre international study. Computerised JSW measurement was undertaken using enhanced and automated versions of existing algorithms. Rates of JSN were examined in the context of a review of published rates of JSN using a variety of techniques.ResultsReproducibility of JSW measurement from microfocal radiographs was improved by the new magnification measurement. Rates of JSN were similar across the studies, but more variable when using standard radiography. The rates of JSN were also consistent with those from previously published investigations; all estimates since 2000, bar one, being consistent with the value 0.05mm/year.ConclusionMicrofocal radiography using the new method lowered the variability of the rate of JSN, but the high cost and low availability of microfocal equipment remains a barrier to its more widespread use. The consistently low but highly variable rates of JSN seen in the review suggest that continued attempts to improve radiographic and mensural techniques are unlikely to significantly reduce required sample sizes

Good intermediate-rank lattice rules based on the weighted star discrepancy

We study the problem of constructing good intermediate-rank lattice rules in the sense of having a low weighted star discrepancy. The intermediate-rank rules considered here are obtained by “copying” rank-1 lattice rules. We show that such rules can be constructed using a component-by-component technique and prove that the bound for the weighted star discrepancy achieves the optimal convergence rate

On the Andreadakis-Johnson filtration of the automorphism group of a free group

The Johnson filtration of the automorphism group of a free group is composed of those automorphisms which act trivially on nilpotent quotients of the free group. We compute cohomology classes as follows: (i) we analyze analogous classes for a subgroup of the pure symmetric automorphism group of a free group, and (ii) we analyze features of these classes which are preserved by the Johnson homomorphism. One consequence is that the ranks of the cohomology groups in any fixed dimension between 1 and n-1 increase without bound for terms deep in the Johnson filtraton.Comment: Corrections; revisions to proof of main theore