Plantar pressure values in patients with ankylosing spondylitis and their relation with clinical and radiological parameters

Aim: In this study, we aimed to determine the plantar pressure values of patients with ankylosing spondylitis (AS) and to identify the relationship of these values with the clinical and radiological parameters which placed in the follow-up of the disease.Materials and Methods: 75 patients with the diagnosis of AS according to the modified New York criteria were included in the study consecutively in outpatient clinic. Exclusion criteria were cognitive dysfunction, visual, auditory and vestibular problems that affect walking on the pedobarography platform independently, history of previous surgery to lower extremity and lower extremity neurologic deficits. Demographic data of the patients such as age, gender and duration of disease were recorded. In clinical assessment disease activity was carried out by applying the BASDAI; functional assessment by applying the BASFI , metrological evaluation by applying BASMI and patient quality of life was evaluated through the ASQoL. In addition, examination of patients for enthesitis was scored according to MASES and MEI, thoracic kyphosis angle was measured with a bubble inclinometer device. The left and right axis angles and mSASSS scores were.determined via patients? radiographic evaluation. both static and dynamic plantar pressures were recorded in pedobarographic studies of patients. The data were evaluated with SPSS 15.0 software. For all results p <0.05 was considered statistically significant.Results: 13 (17.3%) women and 62 (82.7%) male patients were included in the study. The mean age of patients was 37.98 ± 9.96 years. Average disease duration was 115.13 ± 85.61 months. 42.7% of the patients participating in the study (n = 32) had a history of foot pain in the last week. Comparing of patients with foot pain and patients without foot pain by clinical and radiographic examination BASDAI (p <0.001), BASFI (p = 0.002), ASQoL (p <0.001), VASi (p <0.001), VASa (p <0.001), fatigue (p <0.001), difficulty (p <0.001), MASES (p <0.001), MEI (p <0.001) scores and the right axis angle (p = 0.047) were showed statistically significant differences. All scores are higher in patients with foot pain On dynamic plantar pressure comparisons the right mid-foot peak pressure and left middle forefoot peak pressure were lower in high disease activity (BASDAI> 4.1) group from low disease activity group (p = 0.037 and p = 0.022 respectively). In patients with low disease activity the right foot contact area was found higher than patients with high disease activity (p = 0.029). Increased thoracic kyphosis angle was correlated with the decreased static right and left medial forefoot peak pressure (p = 0.05 and p = 0.02 respectively), decreased percentage of the right and left forefoot loading (p <0.001 and p = 0.019, respectively), increased percentage of right hindfoot loading (p <0.001) and increased right peak heel pressure (p = 0.041). Conclusion: We were observed that plantar pressure measurements in patients with AS were correlated with clinical and radiological parameters. We found that especially with increased thoracic kyphosis angle, some of the pressures in forefoot and midfoot measurements were decreased and some in rearfoot were increased. Morover increased BASDAI, BASMI and BASFI scores were associated with decreased forefoot values and increased rearfoot loading. These findings suggest that with the disease progression the total load of rearfoot was increased. Therefore pedobarography seems to be an appropriate tool for the evaluation of the impact of disease on foot and clinical outcome of disease on patients with AS.