Objective. To explore the association between mobility, inflammation, and structural damage in ankylosing spondylitis (AS). Methods. Patients with AS were included in a cross-sectional study in which spinal mobility was measured by the Bath Ankylosing Spondylitis Metrology Index (BASMI) and by the University of Có rdoba Ankylosing Spondylitis Metrology Index (UCOASMI), based on an automated motion analysis. Structural damage was measured by the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS), and activity by the Ankylosing Spondylitis Disease Activity Score (ASDAS) and the Bath Ankylosing Spondylitis Disease Activity (BASDAI). We analyzed the correlations between variables, as well as interaction by multiple linear regression models to reach a predictive equation. Results. Fifty AS patients, mainly men in their mid-40s and with moderate levels of disease activity and structural damage, were included in the study. BASMI and UCOASMI scores showed a strong correlation (r ‫؍‬ 0.89). UCOASMI scores correlated stronger than BASMI with structural damage (r ‫؍‬ 0.72 versus r ‫؍‬ 0.67) and patient's age (r ‫؍‬ 0.68 versus r ‫؍‬ 0.56). Correlations of mobility were weaker with disease activity by the ASDAS (r ‫؍‬ 0.38) and BASDAI (r ‫؍‬ 0.49), and disease duration (r ‫؍‬ 0.40). Multiple linear regression showed that factors associated to mobility by UCOASMI were age, the BASDAI, mSASSS, ASDAS (0:<2.1, 1:>2.1), and disease duration >15 years. The largest weight in the equation corresponded to the mSASSS. The association between the ASDAS and UCOASMI is dependent on disease duration. Conclusion. Mobility in AS is influenced by both structural damage and activity, but definitely also by age and disease duration. Improved mobility should be a relevant target in AS, even more prominently than activity, given its closer relation to structural damage.

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Background Osteoarthritis of the knee (OA) is the most common disease affecting the musculoskeletal system and one of the most important causes of disability among elderly population. Patients are assessed by questionnaires whose response may be influenced to some subjectivity (WOMAC, VAS, SF36). Gait analysis and ground reaction forces (GRF) produce objective and quantitative results of patient status with well-defined patterns. Vertical force curves are characterized by showing two peaks and a valley, showing a graph like an inverted W. Intra-articular injections of hyaluronic acid for the treatment of knee OA have been shown to reduce pain and improve joint function. In this work we have used GRF as evaluation tool in patients with knee OA before and after applying intra-articular treatments. Objectives To analyze ground reaction forces in patients with knee OA before and after intraarticular treatment. Methods 26 patients with knee OA (57.68±8.06 years, 1.65±0.88 m, 87.74±13.06 kg) with a high level of affectation (grade II-III according to Kellgren and Lawrence scale) and 6 healthy subjects as control group with similar characteristics (55.33±5.07 years, 1.70±0.77 m,. 88.52±10.15 kg) were analyzed. Intraarticular injections of hyaluronic acid were applied to patients before and after measurements (one and three months). Vertical, mediolateral and anteroposterior GRF were evaluated using a triaxial force plate (Bertec ® FP4060) Results GRF in three axis and some temporary values as support time and first peak time in vertical force are showed in table. Significant differences between patients and control group in almost all parameters analyzed were found, showing a biomechanical altered gait. Regarding treatment sensitive measures, we could highlight first time peak in vertical force, force in the valley and difference between peak and valley. Sensitive measures also appear in the other two axis with larger braking and impulse forces. Also a shorter support time appears. (A) Before (B) 1 Month (C) 3 Months P Value (D) Control Vertical forces (%BW)  1st peak force 99.16 (2.32) 99.62 (2.20) 99.95 (1.65) 101.63 (6.30)  Valley force 92.28 (2.27) 91.92 (3.65) 91.71 (2.97) B*. C*. D** 90.02 (6.22)  2nd peak force 101.28 (2.35) 100.99 (2.58) 101.84 (2.92) D** 107.23 (5.03)  Force difference peak/valley 7.94 (4.66) 8.39 (3.12) 9.19 (3.33) B**. C**. D** 14.41 (5.05) Time  (%SGC) 31.69 (3.33) 31.23 (3.72) 31.15 (4.32) B*. C*. D** 27.33 (3.15)  Support (s) 1.00 (0.15) 0.97 (0.13) 0.94 (0.12) B*. C*. D** 0.83 (0.13) Medio-Lateral forces (%BW)  Internal 5.46 (1.79) 5.26 (1.28) 5.73 (1.66) B*. D** 4.87 (2.41)  External 2.29 (1.31) 1.65 (0.92) 1.94 (1.01) B*. D** 2.88 (0.76) Antero-posterior forces (%BW)  Braking 8.21 (2.35) 8.96 (2.07) 9.43 (2.43) B*. C*. D** 10.80 (1.54)  Impulse 11.70 (2.14) 12.00 (2.95) 12.72 (3.49) B*. C*. D** 14.62 (1.91) Mean (SD). %BW, as % of body weight. %SGC, as % of stance phase in gait cycle. P value according to A column. *P<0.05, **P<0.001. Concl...

Background Ankylosing spondylitis produces a progressive decrease in spinal mobility with the evolution of the disease. This decrease is due to inflammation and structural damage at radiological level that occurs in neck and spine. Several indices have been validated to quantify this grade of affectation. The most used index to assess structural damage is the mSASSS. This index is evaluated between 0 to 72 points and it measures equally the affectation grade of the neck and lower back. Recently a new index based on motion analysis has been defined wich produces accurate and objective information about mobility, the UCOASMI [1] index. For calculating this index, two cervical mobility and three lumbar mobility measures are used, so cervical UCOASMI and lumbar UCOASMI can be defined. With the evolution of the disease UCOASMI and mSASSS indexes increases with more structural damage and loss of mobility, but what is the relation between lumbar and cervical damage with the evolution of AS? Objectives To analyze the evolution of AS in terms of radiological damage and mobility at the cervical and lumbar area. Methods 76 patients diagnosed with AS (75% male, age 44.1±11.5 years, duration 13.6±9.4 years) were analyzed. A radiologist assessed radiographs for calculating mSASSS. At the Motion Analysis Laboratory of the Reina Sofia University Hospital, UCOTrack system was used to calculate UCOASMI index. For both indices, coefficient cervical/lumbar ratio was calculated to identify which part was more affected. Results Table shows affectation grade in mobility (UCOASMI) and radiographic damage (mSASSS) in total sample and grouped by gender, duration, and affectation grade in mobility. Differences between groups are also showed indicating whether these are statistically significant. Table 1 Gender Time of disease(1) Mobility loss (2) Total (n=76) Men (n=57) Female (n=19) Dif. Medium (n=34) Large (n=42) Dif. Medium (n=36) Large (n=40) Dif. UCOASMI 4.48 (2.24) 4.41 (2.22) 4.45 (2.17) 0.04 3.87 (1.77) 4.94 (2.45) 1.07* 2.65 (1.24) 6.01 (1.54) 3.36** Cervical/Lumbar (%) 48.89 (9.58) 48.68 (10.3) 49.60 (7.21) 0.92 46.60 (10.11) 50.57 (8.93) 3.97 44.95 (9.83) 51.96 (8.05) 7.01** mSASSS 24.79 (18.88) 26.90 (20.77) 16.87 (2.36) −10.03* 18.76 (9.38) 32.23 (24.65) 13.47* 15.58 (5.63) 32.24 (22.44) 16.66** Cervical/Lumbar (%) 48.19 (9.65) 47.19 (10.16) 51.93 (6.72) 4.74 45.73 (10.85) 51.23 (7.10) 5.5 46.91 (12.50) 49.22 (6.69) 2.31 *p<0.05. **p<0.01. (1)Medium <10 years. (2)UCOASMI <4. Conclusions The relation between affectation of cervical and lumbar part seems to be balanced around 50% according to both structural damage and mobility. Mobility differences in genre were not appreciated. While there are differences in the structural damage between male and female, this difference appears similarly in both areas. According to our results, only at initial stages of the disease, lower back is most affected, especially as far as mobility is concerned. References Garrido-Castro JL, Escudero A, Medina-C...

Background Knee osteoarthritis (OA) is the most common disease affecting human locomotion, and one of the most important causes of disability among the elderly population. In order to assess health status of patients self-evaluated questionnaires are commonly used, wich may be influenced by certain degree of subjectivity. Hialuronic acid is a common used treatment to improve knee OA. A force plate connected to a computer allows to analyze postural stability evaluating the center of pressure (CoP) sway in the lateral and sagittal planes. These methods of assessment the postural stability have shown excellent reliability in previous studies. Objectives Analyze the assessment of postural stability in patients with Knee OA using a triaxial force plate. Methods 10 patients with knee OA were analyzed (6 women and 4 men, age 55.3±3.2 years, weight 82.5±12.9 Kgr.) and 6 healthy subjects (4 women and 6 men, age 53.1±1.6 years, weight 78.3±10.4 Kgr.) as control group. Patients had a II-II degree of knee OA according to Kellgren and Lawrence scale. Hyaluronic acid injections were applied into the affected knee. Measures were taken before and after (4 weeks) treatment. A triaxial force plate (Bertec © FP5040) was used to assess postural balance. Patiens remained quiet for 10 seconds on the force plate, first with their eyes open (EO) and then another 10 seconds with their eyes closed (EC). Following parameters were recorded: total CoP distance, distance covered in antero-posterior and medio-lateral directions, area covered, and Romberg test (relation between EC and EO area). Patients fulfilled questionnaires in each test in order to calculate indexes: VAS general, VAS pain, WOMAC, SF-36 and OARSI criteria. Results Significant differences were observed in CoP area in both EO and EC, and in Romberg test, between pre and post treatment measures. Differences between control group and patients were significant in almost all parameters. In questionnaires based indexes, improvements were showed, although these differences were not statistically significant. Correlations were found between CoP sway with EC (p<0.05) and Romberg test (p<0.05) with pain according to VAS. SF-36 index also correlated (p<0.05) with CoP sway in both EO and EC. Conclusions Despite being a pilot study, with a very reduced sample, measurements of postural stability obtained from the force plate were sensitive to treatment. It was also interesting correlations between balance and pain level according to VAS, wich seems to show that pain in knee OA produces certain postural imbalance, as previous studies shown. Future studies with larger sample size may demonstrate our hypothesis, so this kind of technology can be used to assess outcome in knee OA patients and to show effectiveness treatments. Disclosure of Interest None Declared