Brief report: inhibition of interleukin-6 function corrects Th17/Treg cell imbalance in patients with rheumatoid arthritis

OBJECTIVE

From an immunologic standpoint, the mechanisms by which treatment with tocilizumab (TCZ), a humanized anti-interleukin-6 (anti-IL-6) receptor antibody, results in improvement in rheumatoid arthritis (RA) patients are still not fully understood. In vitro studies and studies in mouse models have demonstrated the critical role of IL-6 in Th17 cell differentiation. Th17 lymphocytes have been shown to be strongly involved in RA pathogenesis, and the purpose of this study was to investigate the effect of IL-6 blockade on the balance between Th17 cells and Treg cells in patients with active RA.

METHODS

Patients with active RA for whom TCZ had been prescribed by a rheumatologist were enrolled in this study. Phenotypic analyses of T cell populations were performed, and the Disease Activity Score in 28 joints (DAS28) was assessed. Serum cytokine levels and other parameters of inflammation were measured before the first infusion and after the third infusion of TCZ (8 mg/kg).

RESULTS

Compared to controls, levels of Th17 cells (CD4+IL-17+) were increased and Treg cells (CD4+CD25(high) FoxP3+) were decreased in the peripheral blood of patients with active RA. The suppressive function of circulating Treg cells was not impaired in patients with active RA. TCZ treatment induced a significant decrease in the DAS28 associated with a significant decrease in the percentage of Th17 cells (from a median of 0.9% to 0.45%; P = 0.009) and an increase in the percentage of Treg cells (from a median of 3.05% to 3.94%; P = 0.0039) in all patients.

CONCLUSION

This study demonstrates for the first time that inhibition of IL-6 function by TCZ corrects the imbalance between Th17 cells and Treg cells in patients with RA.

Th1 and Th17 lymphocytes expressing CD161 are implicated in giant cell arteritis and polymyalgia rheumatica pathogenesis

OBJECTIVE

Giant cell arteritis (GCA) is the most frequently occurring vasculitis in elderly individuals, and its pathogenesis is not fully understood. The objective of this study was to decipher the role of the major CD4+ T cell subsets in GCA and its rheumatologic form, polymyalgia rheumatica (PMR).

METHODS

A prospective study of the phenotype and the function of major CD4+ T cell subsets (Th1, Th17, and Treg cells) was performed in 34 untreated patients with GCA or PMR, in comparison with 31 healthy control subjects and with the 27 treated patients who remained after the 7 others withdrew.

RESULTS

Compared with control subjects, patients with GCA and patients with PMR had a decreased frequency of Treg cells and Th1 cells, whereas the percentage of Th17 cells was significantly increased. Furthermore, an analysis of temporal artery biopsy specimens obtained from patients affected by GCA for whom biopsy results were positive demonstrated massive infiltration by Th17 and Th1 lymphocytes without any Treg cells. After glucocorticoid treatment, the percentages of circulating Th1 and Th17 cells decreased, whereas no change in the Treg cell frequency was observed. The frequency of CD161+CD4+ T cells, which are considered to be Th17 cell precursors, was similar in patients and control subjects. However, these cells highly infiltrated GCA temporal artery biopsy specimens, and their ability to produce interleukin-17 in vitro was significantly enhanced in patients with GCA and patients with PMR and was correlated with a decrease in the phosphorylated form of STAT-1.

CONCLUSION

This study is the first to demonstrate that the frequency of Treg cells is decreased in patients with GCA and patients with PMR, and that CD161+CD4+ T lymphocytes, differentiated into Th1 cells and Th17 cells, are involved in the pathogenesis of GCA and PMR.

Cross-cultural adaptation and validation of the French version of the Knee injury and Osteoarthritis Outcome Score (KOOS) in knee osteoarthritis patients

OBJECTIVE

To adapt the Knee injury and Osteoarthritis Outcome Score (KOOS) into French and to evaluate the psychometric properties of this new version.

METHODS

The French version of the KOOS was developed according to cross-cultural guidelines by using the "translation-back translation" method to ensure content validity. KOOS data were then obtained in patients with symptomatic knee osteoarthritis (OA). The translated questionnaire was evaluated in two knee OA population groups, one with no indication for joint replacement (medicine), and the other waiting for joint replacement (surgery). The psychometric properties evaluated were feasibility: percentage of responses, floor and ceiling effects; construct validity: internal consistency using Cronbach's alpha, correlations with osteoarthritis knee and hip quality of life domains using Spearman's rank test, and known group comparison between medicine and surgery groups; reliability: intra-class correlation coefficient (ICC), Bland and Altman representation; responsiveness using data obtained prior to and 3 months after surgery: standardized response mean (SRM), and effect size.

RESULTS

Thirty-seven patients were included in the medicine group (68% women, mean age=70+/-10 years) and 30 in the surgery group (73% women, mean age=71+/-10 years). The percentage of responses was excellent. Neither a floor nor a ceiling effect was observed, except for the sport and recreation subscale (20.6% of patients with the worst possible score in the medicine group, 40 and 0% in the surgery group prior to and after surgery, respectively). Results for internal consistency (Cronbach's alpha ranging from 0.76 to 0.93), and convergent and divergent construct validity were satisfactory. The patients waiting for knee surgery presented with significantly lower scores in all KOOS domains. The reproducibility of measurements of all KOOS subscales was good to excellent, with ICC ranging from 0.755 to 0.914. The responsiveness was high, with SRM ranging from 0.89 to 1.93, and effect size from 1.31 to 2.8.

CONCLUSION

The French version of KOOS is a valid, reliable, and responsive instrument to capture specific aspects of functional disability affecting quality of life of knee OA patients.

Gait analysis as a quantifiable outcome measure in hip or knee osteoarthritis: a systematic review

OBJECTIVES

Kinematic gait analysis consisting of measuring gait parameters (stride length, gait speed, dynamic joint angles) is a potential outcome measure in osteoarthritis (OA). The aim of this study was to evaluate its psychometric properties.

METHODS

A systematic literature search was performed in PUBMED and the Cochrane database until January 2008 by selecting manuscripts assessing any psychometric property of gait analysis in knee or hip OA. Were assessed feasibility (cost, time and access); reliability; discriminant capacity by differences between OA and non-OA patients; construct validity by correlation between gait analysis and OA symptoms: pain or functional disability (Lequesne/WOMAC); and responsiveness by improvement of gait analysis after treatment of OA using effect size.

RESULTS

Among the 252 articles identified, the final analysis included 30 reports (i.e., 781 knee OA patients and 343 hip OA patients). Gait analysis presents various feasibility issues and there was limited evidence regarding reliability (three studies, 67 patients). Discriminant capacity showed significant reduction of gait speed, stride length and knee flexion in OA patients compared to healthy subjects. Few data were available concerning construct validity (three studies, 79 patients). Responsiveness of gait speed was moderate to large with effect size ranging respectively from 0.33 to 0.89 for total knee replacement, and from 0.50 to 1.41 for total hip replacement.

CONCLUSION

Available data concerning validity and reliability of kinematic gait analysis are insufficient to date to consider kinematic parameters as valuable outcome measures in OA. Further studies evaluating a large number of patients are needed.

OARSI-OMERACT definition of relevant radiological progression in hip/knee osteoarthritis

BACKGROUND

Joint space width (JSW) evaluated in millimeters on plain X-rays is the currently optimal recognized technique to evaluate osteoarthritis (OA) structural progression. Data obtained can be presented at the group level (e.g., mean+/-standard deviation of the changes). Such presentation makes difficult the interpretation of the clinical relevance of the reported results. Therefore, a presentation at the individual level (e.g., % progressors) seems more attractive but requires to determining a cut-off. Several methodologies have been proposed to define cut-offs in JSW: arbitrary chosen cut-off, cut-off based on the validity to predict a relevant end-point such as the requirement of total articular replacement or cut-off based on the measurement error such as smallest detectable difference (SDD).

OBJECTIVES

The objective of this OARSI-OMERACT initiative was to define a cut-off evaluated in millimeters on plain X-rays above which a change in JSW could be considered as relevant in patients with hip and knee OA.

METHODS

The first step consisted in a systematic literature research performed using Medline database up to July 2007 to obtain all manuscripts published between 1990 and 2007 reporting a cut-off value in JSW evaluated in millimeters at either the knee or hip level. The second step consisted in a consensus based on the best knowledge of the 11 experts with the support of the available evidence.

RESULTS

Among the 506 articles selected by the search, 47 articles reported cut-off of JSW in millimeters. There was a broad heterogeneity in cut-off values, whatever the methodologies or the OA localization considered (e.g., from 0.12 to 0.84 mm and from 0.22 to 0.78 mm for Knee (seven studies) and hip (seven studies), respectively when considering the data obtained based on the reliability). Based on the data extracted in the literature, the expert committee proposed a definition of relevant change in JSW based on plain X-rays, on an absolute change of JSW in millimeters and on the measurement error e.g., calculation of the SDD using the Bland and Altman technique. The results of the analysis of JSW should be expressed in terms of a dichotomous variable (e.g., progressors yes/no): a patient with a change in JSW during the study over such SDD will fulfill the definition of "progressor". Moreover, the pilot study aimed at evaluating the measurement error should be designed to reflect the different characteristics of the primary study in which the analysis of the radiological findings will be based on (patient's characteristics, centers characteristics, readers).

CONCLUSION

This initiative based on both an Evidence Based Medicine (Systematic Literature Research) and Expert Opinion approach resulted in a proposal of definition of relevant radiological progression in OA to be used as end-point in clinical trials and also recommendations on the conduct of the reliability study allowing such definition.

Does platelet-rich plasma have a role in the treatment of osteoarthritis?

Platelet-rich plasma (PRP) has been generating considerable attention as an intra-articular treatment to alleviate the symptoms of osteoarthritis. Activated platelets release a host of soluble mediators such as growth factors and cytokines, thereby inducing complex interactions that vary across tissues within the joint. In vivo, PRP may promote chondrocyte proliferation and differentiation. The available data are somewhat conflicting regarding potential effects on synovial cells and angiogenesis modulation. PRP probably exerts an early anti-inflammatory effect, which may be chiefly mediated by inhibition of the NF-κB pathway, a hypothesis that requires confirmation by proof-of-concept studies. It is far too early to draw conclusions about the efficacy of PRP as a treatment for hip osteoarthritis. The only randomized trial versus hyaluronic acid showed no significant difference in effects, and no placebo-controlled trials are available. Most of the randomized trials in knee osteoarthritis support a slightly greater effect in alleviating the symptoms compared to visco-supplementation, most notably at the early stages of the disease, although only medium-term data are available. Many uncertainties remain, however, regarding the best administration regimen. Serious adverse effects, including infections and allergies, seem rare, although post-injection pain is more common than with other intra-articular treatments for osteoarthritis.

Hyaluronan for knee osteoarthritis: an updated meta-analysis of trials with low risk of bias

Background

The effectiveness of intra-articular hyaluronic acid (IAHA) injection for knee osteoarthritis (KOA) is debated.

Objectives

To evaluate the effect of IAHA for patients with KOA by analysing data from trials of IAHA versus placebo with low risk of bias, to provide the highest level of evidence.

Methods

A systematic review and meta-analysis was conducted. Randomised controlled trials (RCTs) with a low risk of bias (adequate randomisation and concealment and double-blind design) that investigated IAHA versus placebo (saline solution) injection were eligible. The primary efficacy measure was pain intensity and secondary outcome function at 3 months. The treatment effect was summarised with the standardised mean difference (SMD) calculated from differences in means of pain and function measures between treatment and control groups at 3 months. Trials were pooled by a random-effects model with DerSimonian and Laird weights. Statistical heterogeneity was explored by a visual exploration of forest plots and the I² statistic.

Results

A total of eight RCTs (2 199 randomised patients) met our inclusion criteria. IAHA significantly reduced the pain intensity (SMD=−0.21, 95% CI (95% CI) −0.32 to −0.10) and improved function (SMD=−0.12, 95% CI −0.22 to −0.02). Trials showed no heterogeneity.

Conclusions

This meta-analysis of high-quality trials of IAHA versus placebo shows that IAHA provides a moderate but real benefit for patients with KOA.

Efficacy of tocilizumab in patients with hand osteoarthritis: double blind, randomised, placebo-controlled, multicentre trial

OBJECTIVE

To evaluate the efficacy of tocilizumab, an antibody against IL-6 receptor, in patients with hand osteoarthritis.

METHODS

This was a multicentre, 12-week, randomised, double-blind, placebo-controlled study from November 2015 to October 2018. Patients with symptomatic hand osteoarthritis (pain ≥40 on a 0-100 mm visual analogue scale (VAS) despite analgesics and non-steroidal anti-inflammatory drugs; at least three painful joints, Kellgren-Lawrence grade ≥2) were randomised to receive two infusions 4 weeks apart (weeks 0 and 4) of tocilizumab (8 mg/kg intravenous) or placebo. The primary endpoint was changed in VAS pain at week 6. Secondary outcomes included the number of painful and swollen joints, duration of morning stiffness, patients' and physicians' global assessment and function scores.

RESULTS

Of 104 patients screened, 91 (45 to tocilizumab and 46 to placebo; 82% women; mean age 64.4 (SD 8.7) years) were randomly assigned and 79 completed the 12-week study visit. The mean change between baseline and week 6 on the VAS for pain (primary outcome) was -7.9 (SD 19.4) and -9.9 (SD 20.1) in the tocilizumab and placebo groups (p=0.7). The groups did not differ for any secondary outcomes at weeks 4, 6, 8 or 12. Overall, adverse events were slightly more frequent in the tocilizumab than placebo group.

CONCLUSION

Tocilizumab was no more effective than placebo for pain relief in patients with hand osteoarthritis.

Validation of a numerical rating scale to assess functional impairment in hip and knee osteoarthritis: comparison with the WOMAC function scale

OBJECTIVES

(1) To investigate the psychometric properties of a patient-reported numerical rating scale (NRS) for evaluating functional disability in osteoarthritis (OA), in comparison with the WOMAC function scale and with a physician-reported function NRS; (2) to estimate the patient acceptable symptomatic state (PASS) and the minimal clinically important improvement (MCII) values for treatment with non-steroidal anti-inflammatory drugs (NSAIDs).

METHODS

Data were extracted from a prospective multicentre study involving 1186 patients with knee or hip OA. The psychometric properties assessed were feasibility: percentage of responses, floor and ceiling effects; construct validity by examining the correlations with classically used OA outcomes measures; responsiveness by comparing the results of before and 1 month after treatment with NSAIDs using standardised response mean (SRM) and effect size (ES). The MCII and PASS values of each function scale were calculated by an anchoring method.

RESULTS

No floor or ceiling effect was observed. High correlations were observed as expected between the patient NRS and WOMAC function, pain visual analogue scale and patient global assessment. The responsiveness was moderate to large, with SRM and ES ranging from 0.6 (hip OA) to 0.9 (knee OA) and higher than that of the WOMAC function scale. The PASS was close to 3 for the NRS scales. The MCII appears to be the change that makes the OA functional disability decrease from baseline to the PASS.

CONCLUSION

The patient-reported NRS demonstrated good psychometric properties, similar to the WOMAC function scale and can be regarded as a promising tool in therapeutic evaluation and decision-making in OA.

Effects of loss of metatarsophalangeal joint mobility on gait in rheumatoid arthritis patients

OBJECTIVE

To evaluate the effects of loss of range of motion (ROM) of the metatarsophalangeal (MTP) joint on the kinematic parameters of walking in rheumatoid arthritis (RA) patients.

METHODS

Inclusion of RA patients with inactive disease, no synovitis of the inferior limb and reduced ROM of the MTP joints. Evaluation of the ROM of the MTP dorsal and plantar flexion, and gait analysis using a three-dimensional computerized movement analysis. Calculation of gait parameters and maximal flexion and extension of the hips and knees during walking. Analysis 1 compared the ROM of dorsal and plantar flexion in patients with or without walking pain; 2 compared the gait parameters between patients and controls; 3 investigated a relationship between gait parameters and (i) the ROM of the MTP dorsal and plantar flexion and (ii) the pain at walking; 4 investigated the relationship between the ROM of the MTP dorsal and plantar flexion and maximal flexion and extension of the hip and knee joints during walking.

RESULTS

Nine patients and seven controls were included. The MTP ROM was no different in patients presenting with or without pain at walking. The walking velocity was lower and the stride length shorter in patients than in controls. The walking velocity and the stride length were positively related to the MTP dorsal flexion ROM (r(2)=0.75 and 0.67). There was a negative relationship between maximal flexion of the knee and hips during walking and the underlying MTP dorsal flexion ROM (r(2)=0.67 and 0.54).

CONCLUSION

In RA patients, reduced MTP dorsal flexion mobility induces changes in the walking parameters, including the kinematics of the overlying lower limb joints. Treatment of an RA-impaired forefoot should focus on MTP mobility as well as on pain.

Involvement and prognosis value of CD8(+) T cells in giant cell arteritis

CD8(+) T cells participate in the pathogenesis of some vasculitides. However, little is known about their role in Giant Cell Arteritis (GCA). This study was conducted to investigate CD8(+) T cell involvement in the pathogenesis of GCA. Analyses were performed at diagnosis and after 3 months of glucocorticoid treatment in 34 GCA patients and 26 age-matched healthy volunteers. Percentages of CD8(+) T-cell subsets, spectratype analysis of the TCR Vβ families of CD8(+) T cells, levels of cytokines and chemokines and immunohistochemistry of temporal artery biopsies (TAB) were assessed. Among total CD8(+) T cells, percentages of circulating cytotoxic CD8 T lymphocytes (CTL, CD3(+)CD8(+)perforin(+)granzymeB(+)), Tc17 (CD3(+)CD8(+)IL-17(+)), CD63(+)CD8(+) T cells and levels of soluble granzymes A and B were higher in patients than in controls, whereas the percentage of Tc1 cells (CD3(+)CD8(+)IFN-γ(+)) was similar. Moreover, CD8(+) T cells displayed a restricted TCR repertoire in GCA patients. Percentages of circulating CTL, Tc17 and soluble levels of granzymes A and B decreased after treatment. CXCR3 expression on CD8(+) T cells and its serum ligands (CXCL9, -10, -11) were higher in patients. Analyses of TAB revealed high expression of CXCL9 and -10 associated with infiltration by CXCR3(+)CD8(+) T cells expressing granzyme B and TiA1. The intensity of the CD8 T-cell infiltrate in TAB was predictive of the severity of the disease. This study demonstrates the implication and the prognostic value of CD8(+) T-cells in GCA and suggests that CD8(+) T-cells are recruited within the vascular wall through an interaction between CXCR3 and its ligands.

Cross-cultural adaptation and validation of the French version of the Hip disability and Osteoarthritis Outcome Score (HOOS) in hip osteoarthritis patients

OBJECTIVE

To translate and adapt the Hip disability and Osteoarthritis Outcome Score (HOOS) into French and to evaluate the psychometric properties of this new version, by testing feasibility, internal consistency, construct validity, reliability and responsiveness, in patients with hip osteoarthritis (OA).

METHODS

The French version of the HOOS was developed according to published international guidelines to ensure content validity. The new version was then evaluated in two symptomatic hip OA populations, one with no indication for joint replacement (medical group), and the other waiting for total hip replacement (THR) (surgery group). The psychometric properties assessed were feasibility: percentage of responses, floor and ceiling effects; internal consistency using Cronbach's alpha; construct validity by evaluating correlations with the Lequesne's index and the visual analogic scale (VAS) for pain (Pearson's correlation coefficient); reliability: intra-class correlation coefficient (ICC), Bland et Altman representation; responsiveness by comparing the results of before and 1 month after injection of hyaluronic acid (medical group) and by comparing the pre and 3 months post THR results (surgery group) by calculating standardized response mean (SRM) and effect size (ES).

RESULTS

A total of 88 patients were recruited; 58 in the medicine group (mean age=61.8+/-9 years, range 42-81, 70% women) and 30 in the surgery group (mean age=67.5+/-9 years, range 50-81, 68% women). The percentage of item responses was excellent (99%). Neither a floor nor a ceiling effect was observed, except for a ceiling effect (17.8% of patients with worst possible score) observed prior to surgery in the sport and recreation subscale. The internal consistency was good for four of the five HOOS subscales. As expected, the strongest correlations were observed between all HOOS subscales and Lequesne's index or VAS pain, indicating good construct validity. The reliability was good, with an ICC>0.8 for all subscales. The responsiveness was good for all domains 1 month after hyaluronic acid injection (ES ranging from 0.73 to 1.86 and SRM from 0.51 to 1.04) and high for all domains 3 months after THR (ES ranging from 1.47 to 2.08 and SRM ranging from 1.97 to 3.24).

CONCLUSION

The French version of HOOS demonstrated good psychometric properties and appears to be useful for the evaluation of patient-relevant outcome whatever the severity of hip OA. This study provides a basis for the use of this French version of the HOOS in future clinical trials.

Recommendations of the French Society of Rheumatology on pharmacological treatment of knee osteoarthritis

OBJECTIVES

To establish recommendations for pharmacological treatment of knee osteoarthritis specific to France.

METHODS

On behalf of the French Society of Rheumatology (SFR), a bibliography group analyzed the literature on the efficacy and safety of each pharmacological treatment for knee osteoarthritis. This group joined a multidisciplinary working group to draw up recommendations. Strength of recommendation and quality of evidence level were assigned to each recommendation. A review committee gave its level of agreement.

RESULTS

Five general principles were established: 1) need to combine pharmacological and non-pharmacological treatments, 2) personalization of treatment, 3) symptomatic and/or functional aim of pharmacological treatments, 4) need to regularly re-assess the treatments and 5) discussion about arthroplasty if medical treatment fails. Six recommendations involved oral treatments: 1) paracetamol should not necessarily be prescribed systematically and/or continuously, 2) NSAIDs, possibly as first-line, 3) weak opioids, 4) strong opioids, 5) symptomatic slow-acting drugs of osteoarthritis, and 6) duloxetine (off-label use). Two recommendations involved topical agents (NSAIDs and capsaicin<1%). Three recommendations involved intra-articular treatments: corticosteroid or hyaluronic acid injections that can be proposed to patients. The experts did not draw a conclusion about the benefits of platelet-rich plasma injections.

CONCLUSION

These are the first recommendations of the SFR on the pharmacological treatment of knee osteoarthritis.

Severe hypovitaminosis D correlates with increased inflammatory markers in HIV infected patients

BACKGROUND

Even though it has been suggested that antiretroviral therapy has an impact on severe hypovitaminosis D (SHD) in HIV infected patients, it could be speculated that the different levels of residual inflammation on HAART (Highly Active Anti Retroviral Therapy) could contribute to SHD and aggravate bone catabolism in these patients.

METHODS

A cross-sectional study was carried out in an unselected cohort of 263 HIV infected outpatients consulting during Spring 2010. Clinical examinations were performed and medical history, food habits, sun exposure and addictions were collected. Fasting blood samples were taken for immunological, virological, inflammation, endocrine and bone markers evaluations.

RESULTS

Ninety-five (36%) patients had SHD. In univariate analysis, a significant and positive association was found between SHD and IL6 (p = 0.001), hsCRP (p = 0.04), increased serum C-Telopeptides X (CTX) (p = 0.005) and Parathyroid Hormon (PTH) (p < 0.0001) levels. In multivariate analysis, SHD deficiency correlated significantly with increased IL-6, high serum CTX levels, lower mean daily exposure to the sun, current or past smoking, hepatitis C, and functional status (falls), but not with the time spent on the current HAART (by specific drug or overall).

CONCLUSIONS

SHD is frequent and correlates with inflammation in HIV infected patients. Since SHD is also associated with falls and increased bone catabolism, it may be of interest to take into account not only the type of antiretroviral therapy but also the residual inflammation on HAART in order to assess functional and bone risks. This finding also suggests that vitamin D supplementation may be beneficial in these HIV-infected patients.

Three-dimensional kinematics of the lower limbs in hip osteoarthritis during walking

OBJECTIVE

To describe the kinematic adaptations of all lower limb joints in hip osteoarthritis patients during walking.

METHODS

Patients with unilateral primary hip OA, without associated joint disorders were included. Normal subjects were included as controls. Gait analysis, using a 3-dimensional computerised gait analysis system was used to evaluate the usual spatiotemporal parameters, the peak motion of the hips, knees, and ankles during walking, and the intersegmental coordination of the lower limbs.

RESULTS

Eleven patients, mean age =60.5 ± 7 years and nine controls, mean age=60.3 ± 7 years, were included. The gait of hip OA patients was characterised as follows: a reduced stride length, a reduced maximal flexion and extension in the OA hip, a reduced maximal contralateral hip range of motion, an increased ipsi- and contralateral ankle dorsal flexion, a decreased ipsilateral relative temporal phase between the thighs and shanks segments and an increased ipsilateral relative phase between the shanks and foot segments.

CONCLUSION

The present results suggest that hip OA patients use shorter stride length, less contra lateral and especially ipsilateral hip motion, modify ankles motion, and have a different intra-limb coordination pattern compared to control subjects.

Cross-talk correction method for knee kinematics in gait analysis using principal component analysis (PCA): a new proposal

Background

In 3D gait analysis, the knee joint is usually described by the Eulerian way. It consists in breaking down the motion between the articulating bones of the knee into three rotations around three axes: flexion/extension, abduction/adduction and internal/external rotation. However, the definition of these axes is prone to error, such as the “cross-talk” effect, due to difficult positioning of anatomical landmarks. This paper proposes a correction method, principal component analysis (PCA), based on an objective kinematic criterion for standardization, in order to improve knee joint kinematic analysis.

Methods

The method was applied to the 3D gait data of two different groups (twenty healthy subjects and four with knee osteoarthritis). Then, this method was evaluated with respect to three main criteria: (1) the deletion of knee joint angle cross-talk (2) the reduction of variance in the varus/valgus kinematic profile (3) the posture trial varus/valgus deformation matching the X-ray value for patients with knee osteoarthritis. The effect of the correction method was tested statistically on variabilities and cross-talk during gait.

Results

Cross-talk was lower (p<0.05) after correction (the correlation between the flexion-extension and varus-valgus kinematic profiles being annihilated). Additionally, the variance in the kinematic profile for knee varus/valgus and knee flexion/extension was found to be lower and higher (p<0.05), respectively, after correction for both the left and right side. Moreover, after correction, the posture trial varus/valgus angles were much closer to x-ray grading.

Conclusion

The results show that the PCA correction applied to the knee joint eliminates the cross-talk effect, and does not alter the radiological varus/valgus deformation for patients with knee osteoarthritis. These findings suggest that the proposed correction method produces new rotational axes that better fit true knee motion.

Psychometric properties of the French translation of the reduced KOOS and HOOS (KOOS-PS and HOOS-PS)

OBJECTIVE

To evaluate the psychometric properties of the French KOOS physical function (KOOS-PS) and HOOS physical function (HOOS-PS), specifically its feasibility, reliability, construct validity, and responsiveness.

METHODS

Consecutive outpatients consulting for primary knee or hip osteoarthritis (OA) in a rheumatology department were included. During the initial assessment, patients were asked to complete the Knee injury and Osteoarthritis Outcome Score (KOOS) or Hip disability and Osteoarthritis Outcome Score (HOOS) questionnaire and the OsteoArthritis Knee and Hip Quality Of Life questionnaire (OAKHQOL). The patients were given a second KOOS or HOOS questionnaire to complete and return by mail 2 weeks later. Feasibility was assessed by calculating the percentage of missing items and the floor and ceiling effects. Test-retest reliability was evaluated using the intra-class correlation coefficient (ICC). Convergent and divergent construct validity was determined by comparing the results of the KOOS-PS or HOOS-PS and OAKHQOL questionnaires using Spearman's rank test. Responsiveness was evaluated using data obtained in other hip or knee OA patients prior to and 1 month after intra-articular hyaluronic acid injection, using standardized response mean (SRM) and effect-size (ES).

RESULTS

Eighty-seven patients with knee OA and 50 hip OA patients were included. The KOOS-PS and HOOS-PS scores were obtained for all patients as there were no missing items. Neither a floor nor a ceiling effect was observed. The ICC of KOOS-PS and HOOS-PS was 0.861 (0.763-0.921) and 0.859 (0.725-0.929), respectively. A strong or moderate correlation was observed, as expected, between KOOS-PS, HOOS-PS, and the OAKHQOL physical activities, pain, and mental health domains. A weak correlation was observed, as expected, between KOOS-PS, HOOS-PS, and the other OAKHQOL domains, except for a moderate correlation between the KOOS-PS and social functioning. The responsiveness was demonstrated with SRM and ES of 0.80 and 0.51 (KOOS-PS), 1.10 and 0.62 (HOOS-PS), respectively.

CONCLUSION

The French versions of KOOS-PS and HOOS-PS are reliable, valid, and responsive questionnaires for capturing functional disability in people with knee and hip OA.

Anti-Tumour Necrosis Factor-?? Therapy for Rheumatoid and Other Inflammatory Arthropathies

Anti-tumour necrosis factor (TNF)-alpha represents a major advance in the treatment of rheumatoid arthritis (RA), ankylosing spondylitis and psoriatic arthritis. It is usually well tolerated, but a potential increase in the incidence of some infections in patients taking anti-TNFalpha agents has been reported. Compared with younger people, elderly patients have more co-morbidities and are likely to be taking more medications. Moreover, the aging process induces an increase in the rate of infections. Nevertheless, in recent studies analysing the databases of etanercept trials, the normalised incidence of adverse events, serious adverse events, medically important infections and deaths was not increased in patients aged >or=65 years. However, these trials included patients who might have been healthier than elderly RA patients in the general population and therefore not truly representative. Conflicting results have been reported in several 'real-life' observational studies. Taken together, the available data are reassuring for carefully selected populations, at least for etanercept, but it is not possible to claim that anti-TNFalpha agents do, or do not, pose a particular risk for the general population of older patients. Additional studies aiming at determining the safety and benefit-risk ratio of anti-TNFalpha agents in elderly patients are needed. In addition, since the benefit-risk ratio of anti-TNFalpha agents might be different in patients aged 65, 75 or >80 years, when possible, subgroup analysis might also be useful.

Role of dual-energy CT in the diagnosis and follow-up of gout: systematic analysis of the literature

The aim of this systematic review was to determine the potential role of dual-energy CT in the diagnosis and follow-up of gout with regard to the Outcome Measures in Rheumatology (OMERACT) filter. A systematic analysis of the literature was conducted using the MEDLINE and Cochrane databases and published abstracts of international congresses, according to the criteria of the OMERACT filter: feasibility, reproducibility, validity versus laboratory (serum urate, MSU synovial fluid aspirate) and other imaging modalities for gout, and its sensitivity to change in patients on urate lowering therapy (ULT). Thirty-two articles were found representing a total of 1502 patients. The data on feasibility showed that the examination took little time and involved low levels of radiation but had current limited availability. Intra- and inter-observer reproducibility was excellent, with intra-class correlation coefficients > 0.9. Validity in comparison with polarized-light microscopy showed good sensitivity and specificity (> 80%). The diagnostic performance was better than that of radiography and conventional CT-scan and at least equivalent to that of ultrasonography. The sensitivity to change varied with effect sizes from 0.05 (low) to 1.24 (high) for decrease in the tophus volume following different ULT in gout patients. Dual-energy CT-scan is a reproducible and accurate imaging modality for the diagnosis of gout, particularly for tophaceous gout (intra- or extra-articular). It can become a second-line imaging modality of choice in cases of diagnostic doubt, such as ultrasonography. Its role remains uncertain in the follow-up of gout patients treated with ULT and needs further clarification.

Age-Related Adaptations of Lower Limb Intersegmental Coordination During Walking

Lower-limb intersegmental coordination is a complex component of human walking. Aging may result in impairments of motor control and coordination contributing to the decline in mobility inducing loss of autonomy. Investigating intersegmental coordination could therefore provide insights into age-related changes in neuromuscular control of gait. However, it is unknown whether the age-related declines in gait performance relates to intersegmental coordination. The aim of this study was to evaluate the impact of aging on the coordination of lower limb kinematics and kinetics during walking at a conformable speed. We then assessed the body kinematics and kinetics from gait analyses of 84 volunteers from 25 to 85 years old when walking was performed at their self-selected speeds. Principal Component Analysis (PCA) was used to assess lower-limb intersegmental coordination and to evaluate the planar covariation of the Shank-Thigh and Foot-Shank segments. Ankle and knee stiffness were also estimated. Age-related effects on planar covariation parameters was evaluated using multiple linear regressions (i.e., without a priori age group determination) adjusted to normalized self-selected gait velocity. Colinearity between parameters was assessed using a variation inflation factor (VIF) and those with a VIF < 5 were entered in the analysis. Normalized gait velocity significantly decreased with aging (r = −0.24; P = 0.028). Planar covariation of inter-segmental coordination was consistent across age (99.3 ± 0.24% of explained variance of PCA). Significant relationships were found between age and intersegmental foot-shank coordination, range of motion of the ankle, maximal power of the knee, and the ankle. Lower-limb coordination was modified with age, particularly the coordination between foot, and shank. Such modifications may influence the ankle motion and thus, ankle power. This observation may explain the decrease in the ankle plantar flexor strength mainly reported in the literature. We therefore hypothesize that this modification of coordination constitutes a neuromuscular adaptation of gait control accompanying a loss of ankle strength and amplitude by increasing the knee power in order to maintain gait efficiency. We propose that foot-shank coordination might represent a valid outcome measure to estimate the efficacy of rehabilitative strategies and to evaluate their efficiency in restoring lower-limb synergies during walking.

Severe pyogenic infections in patients taking infliximab

OBJECTIVE

To evaluate the prevalence and risk factors of severe pyogenic infections in rheumatology patients taking infliximab in everyday practice.

METHODS

Regional prospective cohort study of patients taking infliximab for rheumatoid arthritis or ankylosing spondylitis with data collection on standardized forms. The medical records of patients with severe pyogenic infections were subjected to a detailed retrospective review. Patients with and without severe pyogenic infections were compared.

RESULTS

The cohort included 83 patients (55 women and 28 men). Severe pyogenic infections occurred in five (6%) patients (three women and two men), all of whom had acute or underlying risk factors. Higher values were found in these five patients for mean age (65.8 +/- 12 vs. 53.9 +/- 13 years, P = 0.04) and mean daily glucocorticoid dosage (15.5 +/- 9 vs. 6.9 +/- 7 mg/day prednisone-equivalent, P = 0.036), as compared to the other patients.

CONCLUSION

Older age and high-dose glucocorticoid therapy are associated with an increased risk of severe pyogenic infection during infliximab therapy. Caution is in order when starting and monitoring infliximab therapy in patients with risk factors. Our data also emphasize the need for a careful search for risk factors before each infliximab infusion.