Background Pedobarography is a device used for sensitive measurement of ground reaction force. It is used for determination of foot biomechanics. In ankylosing spondylitis (AS) foot disorders are common.

Objectives 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.

Methods 75 patients with the diagnosis of AS according to the modified New York criteria were recruited 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 and gender were recorded. Disease activity was assessed with BASDAI. Functional status (BASFI), quality of life (ASQoL) and metrological score (BASMI), enthesis score (MESES, MEI) were assessed. Thoracic kyphosis angle was measured with a bubble inclinometer device. By radiographic evaluation left and right axis angles and mSASSS scores were determined. 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 Seventy five AS patients (62 male) with mean age 37,98 (SD=9,96) years were recruited. The disease duration was 115,13 (SD=85,61) months. 42.7% of participants (32 patients) had a history of foot pain in the last week. Patients with foot pain had higher BASDAI (p<0.001), BASFI (p=0.002), ASQoL (p<0.001), MASES (p<0.001) and MEI (p<0.001) scores. Dynamic 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). Thoracic kyphosis angle was correlated with the static right and left medial forefoot peak pressure (p=0.05 and p=0.02 respectively), the percentage of the right and left forefoot loading (p<0.001 and p=0.019, respectively), percentage of right hindfoot loading (p<0.001) and right peak heel pressure (p=0.041).

Conclusions We observed that plantar pressure measurements in patients with AS correlated with clinical and radiological parameters. Especially with increased thoracic kyphosis angle, some of the pressures in forefoot and midfoot measurements were decreased and some in rearfoot were increased. Moreover 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.

References

1. Sahin N, Ozcan E, Baskent A, Karan A, Ekmeci O, Kasikcioglu E. Isokinetic evaluation of ankle muscle strength and fatigue in patients with ankylosing spondylitis. Eur J Phys Rehabil Med. 2011 Sep;47(3):399-405. Epub 2011 Mar 2.

Disclosure of Interest None Declared