Significant functional impairment and disability in individuals with psoriatic arthritis and Achilles tendon pain: a cross-sectional observational study.

The Achilles tendon (AT) insertion is the most common site of enthesitis in psoriatic arthritis (PsA). The structure and function of the AT in PsA, and the prevalence of mid-portion pathology, is unknown. To compare the structure and function of the AT in people with PsA with self-reported AT pain (PsA + AT), PsA without self-reported AT pain (PsA-AT) and healthy controls. A cross-sectional, observational study was conducted. The ATs were assessed by clinical and US examination (B-mode and Power Doppler), performance-based testing (bilateral heel raise test (HRT) and 10 m walk test), and patient-reported outcome measures (PROMs) (including the Victorian Institute of Sport Assessment-Achilles [VISA-A]). Between-group differences were described using descriptive statistics, Chi-squared testing, parametric (1-way ANOVA) and non-parametric (Mann-Whitney or Kruskal-Wallis) testing. 22 PsA (11 per group) and 11 healthy control participants who were comparable in terms of sex, age, and BMI (PsA-AT = longer PsA disease duration) were recruited. VISA-A scores were significantly worse in the PsA + AT group compared to the PsA-AT group and healthy controls (p < 0.001). Inflammatory US features were significantly more prevalent in the PsA + AT group (p < 0.001). Mid-portion AT pathology was observed in the PsA + AT group, irrespective of entheseal disease. Clinical examination alone missed 5/7 cases of 'active' US-confirmed AT enthesitis. AT functional deficits were significant in the PsA + AT group and both PsA groups had lower HRT repetition rates and walked slower compared to healthy controls. Less than 1/3 of the PsA + AT group had received podiatry or physiotherapy care. Significant differences in the structure and function of the AT in PsA were noted. Despite management in line with current guidance, AT pain appears to persist and can result in severe functional impairment.

EFAS Score - Validation of Danish Version by the Score Committee of the European Foot and Ankle Society (EFAS).

BACKGROUND: The Score Committee of the European Foot and Ankle Society (EFAS) developed, validated, and published the EFAS Score in 13 languages. Currently, the Danish version completed data acquisition and underwent further validation. METHODS: The data were collected pre-operatively and post-operatively at a minimum follow-up of 3 months and mean follow-up of 6 months. Item reduction, scale exploration, confirmatory analyses and responsiveness were executed using classical test theory and item response theory. RESULTS: The internal consistency was confirmed in the Danish version (Cronbach's Alpha 0.88). The Standard Error of Measurement (SEM) was 0.31 and is similar to other language versions. Between baseline and follow-up, 77.2% of patients showed an improvement on their EFAS score, with adequate responsiveness (effect size 1.05). CONCLUSIONS: The Danish EFAS Score version was successfully validated in patients with a wide variety of foot and ankle pathologies. All score versions are freely available at www.efas.net.

Suitability of the animated activity questionnaire for use as computer adaptive test: establishing the AAQ-CAT.

PURPOSE: The animated activity questionnaire (AAQ) is a computer-based measure of activity limitations. To answer a question, patients choose the animation of a person performing an activity that matches their own level of limitation. The AAQ has not yet been tested for suitability to be applied as computer-adaptive test (CAT). Thus, the objective of this study was to develop and evaluate an AAQ-based CAT to facilitate the application of the AAQ in daily clinical care. METHODS: Patients (n = 1408) with hip/knee osteoarthritis from Brazil, Denmark, France, The Netherlands, Norway, Spain, and the UK responded to all 17 AAQ items. Assumptions of item-response theory (IRT) modelling were investigated. To establish item parameters for the CAT, a graded response model was estimated. To evaluate the performance of post-hoc simulated AAQ-based CATs, precision, test length, and construct validity (correlations with well-established measures of activity limitations) were evaluated. RESULTS: Unidimensionality (CFI = 0.95), measurement invariance (R2-change < 2%), and IRT item fit (S-X2 p > .003) of the AAQ were supported. Performing simulated CATs, the mean test length was more than halved (≤ 8 items), while the range of precise measurement (standard error ≤ 0.3) was comparable to the full AAQ. The correlations between original AAQ scores and three AAQ-CAT versions were ≥ 0.95. Correlations of AAQ-CAT scores with patient-reported and performance measures of activity limitations were ≥ 0.60. CONCLUSION: The almost non-verbal AAQ-CAT is an innovative and efficient tool in patients with hip/knee osteoarthritis from various countries, measuring activity limitations with lower respondent burden, but similar precision and construct validity compared to the full AAQ.

EFAS Score-Validation of Spanish and Estonian Versions by the Score Committee of the European Foot and Ankle Society (EFAS).

BACKGROUND: The Score Committee of the European Foot and Ankle Society (EFAS) developed, validated, and published the EFAS Score in 11 languages (Dutch, English, German, Finnish, French, Italian, Polish, Portuguese, Persian, Swedish, Turkish). From other languages under validation, the Spanish and Estonian versions completed data acquisition and underwent further validation. METHODS: The EFAS Score was developed and validated in three stages: 1) item (question) identification (completed during the initial validation study), 2) item reduction and scale exploration (completed during the initial validation study), 3) confirmatory analyses and responsiveness of the Spanish and Estonian versions (completed during the initial validation study in seven other languages). The data were collected pre-operatively and post-operatively at a minimum follow-up of 3 months and mean follow-up of 6 months. Item reduction, scale exploration, confirmatory analyses and responsiveness were executed using classical test theory and item response theory. RESULTS: The internal consistency of the scale was confirmed in the Spanish and Estonian versions (Cronbach's Alpha>0.8). Responsiveness was good, with moderate to large effect sizes in both languages, and evidence of a statistically significant positive association between the EFAS Score and patient-reported improvement. CONCLUSIONS: The Spanish and Estonian EFAS Score versions were successfully validated in orthopaedic ankle and foot surgery patients, with a wide variety of foot and ankle pathologies. All score versions are freely available at www.efas.net.

Patients' and clinicians' perspectives on the clinical utility of the Rheumatoid Arthritis Foot Disease Activity Index.

Although patient-reported outcome measures (PROMs) are recommended in clinical practice, their application in routine care is limited. The Rheumatoid Arthritis Foot Disease Activity Index (RADAI-F5) is a validated PROM for assessing foot disease in rheumatoid arthritis (RA). To explore patient and clinician opinions and perceptions of the clinical utility of the Rheumatoid Arthritis Foot Disease Activity Index (RADAI-F5), eight RA patients and eight clinicians routinely involved in the management of RA patients participated in one semi-structured remote video-based interview. They provided their perspectives on the barriers and facilitators to clinical implementation of the RADAI-F5. Three global themes were identified; 'Feet are a priority' as the impact of RA on the feet negatively impacted upon patient quality of life. The second theme was 'Need for a clinically feasible foot PROM' as participants recognised the current lack of a clinically feasible tool to determine RA foot disease. The third global theme of 'Implementation' was drawn together to form two subordinate themes: 'Facilitators to RADAI-F5 implementation' as the tool can promote communication, guide management, help screen foot symptoms, monitor foot disease status and treatments, and promote patient education and; 'Barriers to RADAI-F5 implementation' as there were associated practical difficulties, including lack of appointment time, administrative burdens, IT barriers and preference for further RADAI-F5 validation using imaging. The RADAI-F5 has significant potential as a clinical tool to aid foot disease management. However, implementation challenges must be overcome before broad adoption in rheumatology clinics.

Barriers and facilitators to physical activity in people with an inflammatory joint disease: a mixed methods study.

BACKGROUND: Physical activity has been shown to be of great benefit to people with an inflammatory joint disease (IJD), however people with an IJD have been shown to be very inactive compared to the general population. The aims of this study were to explore 1) whether the transition from a National Health Service (NHS)-run exercise programme into exercising in the community could be achieved successfully; and 2) the barriers and facilitators during the transition period. METHODS: This study adopted a complementary mixed-methods study design including a qualitative approach using focus groups and a prospective cohort study. Descriptive statistics were used to summarise the cohort study data. All variables were assessed for normality of distribution using the Sharpiro-Wilk test. Paired t-tests or Wilcoxon tests were undertaken for two consecutive assessment timepoints; one-way repeated measures ANOVAs or Friedman's tests for three consecutive assessment timepoints. Micro-interlocutor analysis was used to analyse the focus group data. Areas of congruence and incongruence were explored by confirming the statistical results against the qualitative results. The adapted ecological model of the determinants of physical activity was then used as a framework to describe the findings. RESULTS: A successful transition was defined as still exercising in the community 6-months post discharge from the NHS-run Inflammatory Arthritis Exercise Programme. This was self-reported to be 90% of the cohort. An individual barrier to physical activity in people with an IJD was found to be the unpredictable nature of their condition. Other barriers and facilitators found were similar to those found in the general population such as recreation facilities, locations, transportation and cost. Other facilitators were similar to those found in people living with other chronic long-term conditions such as the importance of peer support. CONCLUSIONS: 90% of the cohort data were defined as a successful transition. People with an IJD have similar barriers and facilitators to exercise as the general population and those living with other chronic long-term conditions. A barrier which appears to be unique to this population group is that of the unpredictable nature of their condition which needs to be considered whenever tailoring any intervention.

EFAS Score - Validation of Portuguese Version by the Score Committee of the European Foot and Ankle Society (EFAS).

BACKGROUND: The Score Committee of the European Foot and Ankle Society (EFAS) developed, validated, and published the EFAS Score in ten languages (English, German, French, Italian, Polish, Dutch, Swedish, Finnish, Turkish, Portuguese). From other languages under validation, the Portuguese version completed data acquisition and underwent further validation. METHODS: The Portuguese version of the EFAS Score was developed and validated in three stages: 1) item (question) identification (completed during initial validation study), 2) item reduction and scale exploration (completed during initial validation study), 3) confirmatory analyses and responsiveness of Portuguese version (completed during initial validation study in nine other languages). The data were collected pre-operatively and post-operatively at a minimum follow-up of 3 months and mean follow-up of 6 months. Item reduction, scale exploration, confirmatory analyses and responsiveness were executed using classical test theory and item response theory. RESULTS: The internal consistency was confirmed in the Portuguese version (Cronbach's Alpha 0.84). The Standard Error of Measurement (SEM) was 0.27 and is similar to other language versions. Between baseline and follow-up, 69.4% of patients showed an improvement on their EFAS score, with adequate responsiveness (effect size 0.64). CONCLUSIONS: The Portuguese EFAS Score version was successfully validated in patients with a wide variety of foot and ankle pathologies. All score versions are freely available at www.efas.net.

EFAS Score -Validation of Persian Version by the Score Committee of the European Foot and Ankle Society (EFAS).

BACKGROUND: The Score Committee of the European Foot and Ankle Society (EFAS) developed, validated, and published the EFAS Score in nine European languages (English, German, French, Italian, Polish, Dutch, Swedish, Finnish, Turkish). From other languages under validation, the Persian version finished data acquisition and underwent further validation. METHODS: The Persian version of the EFAS Score was developed and validated in three stages: 1) item (question) identification (completed during initial validation study), 2) item reduction and scale exploration (completed during initial validation study), 3) confirmatory analyses and responsiveness of Persian version (completed during initial validation study in nine other languages). The data were collected pre-operatively and post-operatively at a minimum follow-up of 3 months and mean follow-up of 6 months. Item reduction, scale exploration, confirmatory analyses and responsiveness were executed using classical test theory and item response theory. RESULTS: The internal consistency was confirmed in the Persian version (Cronbach's Alpha 0.82). The Standard Error of Measurement (SEM) was 0.38 and is similar to other language versions. Between baseline and follow-up, 97% of patients showed an improvement on their EFAS score, with excellent responsiveness (effect size 1.93). CONCLUSIONS: The Persian EFAS Score version was successfully validated in patients with a wide variety of foot and ankle pathologies. All score versions are freely available at www.efas.co.

EFAS Score - validation of Finnish and Turkish versions by the Score Committee of the European Foot and Ankle Society (EFAS).

BACKGROUND: The Score Committee of the European Foot and Ankle Society (EFAS) developed, validated, and published the EFAS Score in seven European languages (English, German, French, Italian, Polish, Dutch, Swedish). From other languages under validation, the Finnish and Turkish versions finished data acquisition and underwent further validation. METHODS: The EFAS Score was developed and validated in three stages: 1) item (question) identification (completed during initial validation study), 2) item reduction and scale exploration (completed during initial validation study), 3) confirmatory analyses and responsiveness of Finnish and Turkish version (completed during initial validation study in seven other languages). The data were collected pre-operatively and post-operatively at a minimum follow-up of 3 months and mean follow-up of 6 months. Item reduction, scale exploration, confirmatory analyses and responsiveness were executed using classical test theory and item response theory. RESULTS: The internal consistency of the scale was confirmed in the Finnish and Turkish versions (Cronbach's Alpha >0.8). Responsiveness was good, with moderate to large effect sizes in both languages, and evidence of a statistically significant positive association between the EFAS Score and patient-reported improvement. CONCLUSIONS: The Finnish and Turkish EFAS Score versions were successfully validated in the orthopaedic ankle and foot surgery patients, including a wide variety of foot and ankle pathologies. All score versions are freely available at www.efas.co.

Impact of exercise on articular cartilage in people at risk of, or with established, knee osteoarthritis: a systematic review of randomised controlled trials.

OBJECTIVE: To investigate the impact of knee joint loading exercise on articular cartilage in people at risk of, or with established, knee osteoarthritis (OA) by conducting a systematic review of randomised controlled trials (RCTs). DESIGN: We followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. DATA SOURCES: We performed a literature search with no restriction on publication year or language in MEDLINE, EMBASE, CINAHL, the Cochrane Central Register of Controlled Trials and Web of Science up to September 2017. ELIGIBILITY CRITERIA: RCTs investigating the impact of exercise on MRI-assessed articular cartilage in people over 18 years of age. RESULTS: We included nine trials, including a total of 14 comparisons of cartilage morphometry, morphology and composition outcomes, of which two included participants at increased risk of knee OA and 12 included participants with knee OA. In participants at increased risk, one study comparison reported no effect on cartilage defects and one had positive effects on glycosaminoglycans (GAG). In participants with OA, six study comparisons reported no effect on cartilage thickness, volume or defects; one reported a negative effect and one no effect on GAG; two reported a positive effect and two no effect on collagen. CONCLUSIONS: Knee joint loading exercise seems to not be harmful for articular cartilage in people at increased risk of, or with, knee OA. However, the quality of evidence was low, including some interventions studying activities considered outside the therapeutic loading spectrum to promote cartilage health.

Association of malalignment, muscular dysfunction, proprioception, laxity and abnormal joint loading with tibiofemoral knee osteoarthritis - a systematic review and meta-analysis.

BACKGROUND: To investigate (1) the association of specific biomechanical factors with knee osteoarthritis and knee osteoarthritis development, and (2) the impact of other relevant risk factors on this association. METHODS: MEDLINE, EMBASE, CINAHL and SPORTDiscus were searched up until April 2017. Studies were included if they fulfilled the following criteria: the study 1) assessed the association of a biomechanical factor with knee osteoarthritis, or knee osteoarthritis development; 2) reported on skeletal malalignment, muscular dysfunction, impaired proprioception, laxity and abnormal loading during gait; 3) was a cohort study with participants developing knee osteoarthritis and participants not developing knee osteoarthritis, or a case-control or cross-sectional study with participants with knee osteoarthritis and without knee osteoarthritis. Risk of bias was assessed with the QUIPS tool and meta-analyses were performed using random effects models. RESULTS: Of 6413 unique studies identified, 59 cross-sectional studies were eligible for meta-analyses (9825 participants, 5328 with knee osteoarthritis). No cohort studies fulfilled the inclusion criteria. Compared with healthy controls, patients with knee osteoarthritis have higher odds of having lower muscle strength, proprioception deficits, more medial varus-valgus laxity and less lateral varus-valgus laxity. Patients with medial knee osteoarthritis have higher odds of having a higher knee adduction moment than healthy controls. Level of evidence was graded as 'very low' to 'moderate' quality. Due to large between study differences moderation of other risk factors on biomechanical risk factors could not be evaluated. CONCLUSIONS: Patients with knee osteoarthritis are more likely to display a number of biomechanical characteristics. The causal relationship between specific biomechanical factors and the development of knee osteoarthritis could not be determined as no longitudinal studies were included. There is an urgent need for high quality, longitudinal studies to evaluate the impact of specific biomechanical factors on the development of knee osteoarthritis. TRIAL REGISTRATION: (PROSPERO ID: CRD42015025092 ).

Knee extensor muscle weakness and radiographic knee osteoarthritis progression.

Background and purpose - Knee extensor (KE) muscle weakness is a modifiable feature commonly observed in individuals with knee osteoarthritis (KOA) and constitutes a potential target for patient-specific interventions. Therefore, in this study, we explored whether KE weakness is associated with radiographic (medial and/or lateral) KOA progression and how this relationship differs depending on frontal plane knee alignment and sex. Patients and methods - We studied 3,075 knees (1,961 participants, 58% female) from the Osteoarthritis Initiative with radiographic Kellgren-Lawrence grade 1-3. Peak KE torque (Nm/kg) was assessed at baseline, and progression defined as fixed-location joint space width loss (≥ 0.7mm) in medial and lateral tibiofemoral compartments from baseline to 4-year follow-up. Knee-based generalized estimating equations, stratified by alignment (malaligned vs. neutral), estimated the relative risk (RR) of progression for those in the lowest (and middle) vs. highest KE torque group (split by tertiles). Secondary analyses explored whether this relationship was compartmental- or sex-specific. Results - Being in the lowest (or middle) compared with the highest torque group increased the risk of progression in neutrally aligned knees (relative risk [RR] 1.2 [95% CI 1.0-1.4]; and 1.2 [CI 1.0-1.4], respectively), but not after adjusting for age, sex, BMI, pain, and radiographic severity. In secondary analyses, women with neutral alignment in the lowest compared with the highest torque group had significantly increased risk of lateral compartment progression independent of age, BMI, disease severity, and pain (RR 1.3 [CI 1.0-1.8]). No association was observed between KE torque and KOA progression in men, irrespective of alignment. Interpretation - These results identify a potentially important clinical phenotype: KE weakness may be a more important risk factor for radiographic KOA progression in women without knee malalignment.

EFAS Score - Multilingual development and validation of a patient-reported outcome measure (PROM) by the score committee of the European Foot and Ankle Society (EFAS).

BACKGROUND: A scientifically sound validated foot and ankle specific score validated ab initio for different languages is missing. The aim of a project of the European Foot and Ankle Society (EFAS) was to develop, validate, and publish a new score(the EFAS-Score) for different European languages. METHODS: The EFAS Score was developed and validated in three stages: (1) item (question) identification, (2) item reduction and scale exploration, (3) confirmatory analyses and responsiveness. The following score specifications were chosen: scale/subscale (Likert 0-4), questionnaire based, outcome measure, patient related outcome measurement. For stage 3, data were collected pre-operatively and at a minimum follow-up of 3 months and mean follow-up of 6 months. Item reduction, scale exploration, confirmatory analyses and responsiveness were executed using analyses from classical test theory and item response theory. RESULTS: Stage 1 resulted in 31 general and 7 sports related questions. In stage 2, a 6-item general EFAS Score was constructed using English, German, French and Swedish language data. In stage 3, internal consistency of the scale was confirmed in seven languages: the original four languages, plus Dutch, Italian and Polish (Cronbach's Alpha >0.86 in all language versions). Responsiveness was good, with moderate to large effect sizes in all languages, and significant positive association between the EFAS Score and patient-reported improvement. No sound EFAS Sports Score could be constructed. CONCLUSIONS: The multi-language EFAS Score was successfully validated in the orthopaedic ankle and foot surgery patient population, including a wide variety of foot and ankle pathologies. All score versions are freely available at www.efas.co.

Three trajectories of activity limitations in early symptomatic knee osteoarthritis: a 5-year follow-up study.

OBJECTIVES: Knee osteoarthritis (OA) is a leading cause of activity limitations. The knee OA population is likely to consist of subgroups. The aim of the present study was to identify homogeneous subgroups with distinct trajectories of activity limitations in patients with early symptomatic knee OA and to describe characteristics of these subgroups. METHODS: Follow-up data over a period of 5 years of 697 participants with early symptomatic knee OA from the Cohort Hip and Cohort Knee (CHECK) were used. Activity limitations were measured yearly with the Western Ontario and McMaster Universities Osteoarthritis Index. Latent class growth analyses identified homogeneous subgroups with distinct trajectories of activity limitations. Multivariable regression analyses examined differences in characteristics between the subgroups. RESULTS: Three subgroups were identified. Participants in Subgroup 1 ('good outcome'; n=330) developed or displayed slight activity limitations over time. Participants in Subgroup 2 ('moderate outcome'; n=257) developed or displayed moderate activity limitations over time. Participants in subgroup 3 ('poor outcome'; n=110) developed or displayed severe activity limitations over time. Compared with the 'good outcome' subgroup, the 'moderate outcome' and 'poor outcome' subgroups were characterised by: younger age, higher body mass index, greater pain, bony tenderness, reduced knee flexion, hip pain, osteophytosis, ≥3 comorbidities, lower vitality or avoidance of activities. CONCLUSIONS: Based on the 5-year course of activity limitations, we identified homogeneous subgroups of knee OA patients with good, moderate or poor outcome. Characteristics of these subgroups were consistent with existing knowledge on prognostic factors regarding activity limitations, which supports the validity of this classification.

Metatarsophalangeal joint pain in psoriatic arthritis: a cross-sectional study.

OBJECTIVE: The aim of this study was to identify independent predictors of pain at the MTP joints in patients with PsA. METHODS: Thirty-four consecutive patients with PsA (mean age 45.3 years, 65% female, mean disease duration 9.9 years) and 22 control participants (mean age 37.9 years, 64% female) underwent clinical and US examination to determine the presence of pain, swelling, synovitis, erosions, effusions and submetatarsal bursae at the MTP joints. Mean barefoot peak plantar pressures were determined at each MTP joint. Levels of pain, US-determined pathology and peak pressures were compared between groups. Binary logistic regression was used to identify demographic, clinical examination-derived, US-derived and plantar pressure predictors of pain at the MTP joints in the PsA group. RESULTS: The presence of pain, deformity, synovitis, erosions (P < 0.001) and submetatarsal bursae and peak plantar pressure at MTP 3 (P < 0.05) were significantly higher in the PsA group. MTP joint pain in PsA was independently predicted by high BMI, female gender and the presence of joint subluxation, synovitis and erosion. CONCLUSION: These results suggest local inflammatory and structural factors, together with systemic factors (gender, BMI), are predominantly responsible for painful MTP joints in PsA, with no clear role for plantar pressure characteristics.

Kinematic, kinetic and electromyographic response to customized foot orthoses in patients with tibialis posterior tenosynovitis, pes plano valgus and rheumatoid arthritis.

OBJECTIVE: To describe the effect of customized foot orthoses (FOs) on the kinematic, kinetic and EMG features in patients with RA, tibialis posterior (TP) tenosynovitis and associated pes plano valgus. METHODS: Patients with RA and US-confirmed tenosynovitis of TP underwent gait analysis, including three-dimensional (3D) kinematics, kinetics, intramuscular EMG of TP and surface EMG of tibialis anterior, peroneus longus, soleus and medial gastrocnemius. Findings were compared between barefoot and shod with customized FO conditions. RESULTS: Ten patients with RA with a median (range) disease duration of 3 (1-18) years were recruited. Moderate levels of foot pain and foot-related impairment and disability were present with moderately active disease states. Altered timing of the soleus (P = 0.05) and medial gastrocnemius (P = 0.02) and increased magnitude of tibialis anterior (P = 0.03) were noted when barefoot was compared with shod with FO. Trends were noted for reduced TP activity in the contact period (P = 0.09), but this did not achieve statistical significance. Differences in foot motion characteristics were recorded for peak rearfoot eversion (P = 0.01), peak rearfoot plantarflexion (P < 0.001) and peak forefoot abduction (P = 0.02) in the shod with FOs compared with barefoot conditions. No differences in kinetic variables were recorded. CONCLUSION: This study has demonstrated, for the first time, alterations in muscle activation profiles and foot motion characteristics in patients with RA, pes plano valgus and US-confirmed TP tenosynovitis in response to customized FOs. Complex adaptations were evident in this cohort and further work is required to determine whether these functional alterations lead to improvements in patient symptoms.

The avoidance model in knee and hip osteoarthritis: a systematic review of the evidence.

The avoidance model in patients with knee and hip osteoarthritis (OA) hypothesizes that pain and psychological distress lead to avoidance of activities, and thereby to muscle weakness and activity limitations. This paper systematically reviews the scientific evidence for the validity of this avoidance model. A qualitative data synthesis was used to identify levels of evidence. Sixty studies were included. In knee OA, strong evidence was found that avoidance of activities is associated with activity limitations via muscle weakness (mediation by muscle weakness), strong evidence was found for an association between muscle weakness and activity limitations, and weak evidence was found that pain and psychological distress are associated with muscle weakness via avoidance of activities (mediation by avoidance). In hip OA, weak evidence was found for mediation by muscle weakness; and strong evidence was found for an association between muscle weakness and activity limitations. More research is needed on the consecutive associations between pain or psychological distress, avoidance of activities and muscle weakness, and to confirm causal relationships.

Measurement properties of the Dutch version of the Western Ontario Shoulder Instability Index (WOSI).

BACKGROUND: The Western Ontario Shoulder Instability Index (WOSI) is a disease-specific shoulder questionnaire to measure quality of life in patients with shoulder instability. The aim of the present study was to translate the WOSI into Dutch and assess its principal measurement properties. METHODS: The WOSI was translated into Dutch according to guidelines in the literature. Fifty-two shoulder instability patients completed the questionnaire twice within 2 weeks. We assessed internal consistency (Cronbach's alpha), test-retest reliability [Intraclass Correlation Coefficient (ICC)], standard error of measurement (SEM), smallest detectable change (SDC) and reliable change index. The Bland-Altman analysis was applied to assess test-retest agreement and floor and ceiling effects were calculated. RESULTS: Cronbach's alpha was 0.95 for the total WOSI score (range 0.88-0.95 for the 4 domains). ICC for the total WOSI score was 0.91 (range 0.79-0.90 for domains), SEM was 130.6 for the total WOSI score resulting in a SDC of 362.0, which is 17.3 % of the maximum obtainable score of 2100. Bland-Altman analysis showed no systematic differences or consistent bias between the two assessments. We observed no relevant floor and ceiling effects. CONCLUSION: The results of the present study suggest the Dutch version of the WOSI is a reliable tool for clinical assessment and scientific evaluation. It shows high values for Cronbach's alpha and ICC implying excellent internal consistency and good test-retest reliability.

What do we miss? ASAS non-responders on anti-TNF therapy show improvement in performance-based physical function.

OBJECTIVE: A prospective study was conducted in order to establish whether AS patients, who are defined as non-responders after 3 months of anti-TNF therapy, show improvement on performance-based tests of physical functioning. METHODS: At baseline and 3 months after the start of anti-TNF therapy, AS patients completed seven performance-based tests of physical functioning, questionnaires on self-reported physical functioning (BASFI) and disease activity (BASDAI), and a pain and a global patient assessment. The concordance between ≥ 20% intra-individual improvement on the performance-based test of physical functioning and (i) response to anti-TNF therapy [Assessment of SpondyloArthritis International Society 20% (ASAS20) response] and (ii) ≥ 20% intra-individual improvement on self-reported physical functioning (BASFI) was assessed. RESULTS: One hundred AS patients were included, of which 82 patients completed all tests at both time points. After 3 months of anti-TNF therapy, 27 (32.9%) patients were categorized as non-responders according to the ASAS20 response criteria. Improvement in performance-based physical functioning was seen in 13 of the 27 non-responders (48.1%) (i.e. n = 13/82 = 15.9% of the total group). Furthermore, 30 (36.6%) patients showed no improvement on self-reported physical functioning (BASFI). However, 17 of the 30 (56.7%) patients did improve on the performance-based tests of physical functioning (i.e. n = 17/82 = 20.7% of the total group). CONCLUSION: After 3 months of anti-TNF therapy, performance-based tests of physical functioning showed improvement in 48.1% of the ASAS20 non-responders. With these performance-based tests, new information on outcome after anti-TNF therapy can be generated. Using performance-based tests alongside the BASFI could have additional value in the evaluation of outcomes for patients receiving anti-TNF therapy.