A Study To Investigate Any Potential Effects On The Foot Of A Commonly Prescribed Off-The-Shelf Foot Orthosis In Patients With Early Diagnosed Rheumatoid Arthritis (RA)

Rheumatoid Arthritis (RA) frequently affects the foot. Custom moulded foot orthoses are effective in the management of the foot in RA; however the process of manufacture is lengthy, resulting in a delay of treatment for the patient. Offthe- shelf foot orthoses can be dispensed at the chairside on the day of diagnosis, so the patient receives treatment immediately. This is particularly crucial in RA, as early intervention is thought to improve patient outcomes in the long term. Anecdotal evidence suggests that Podiatrists do prescribe off-the-shelf foot orthoses for the management of the foot in RA; however no clinical studies exist to support this practice. The aim of this study was to investigate any potential effects on the foot of one commonly prescribed off-the-shelf foot orthosis, in patients with early RA. The type of off-the-shelf foot orthosis used was the Slimflex™ Plastic which has been shown to be a commonly used off-the-shelf foot orthosis by Podiatrists in the management of patients with RA in Scotland (Cameron et al. 2009). A total of 35 patients diagnosed with RA, with a mean age of 52.4 years (SD 13.3 years) and median disease duration of 0.5 years (IQR 1.8 years) were included. Local ethical approval was obtained. The study used a repeated measures design, with data collected at baseline, three months, and six months when patients were barefoot, shod, and with foot orthoses, to investigate any effects over time and between conditions. The primary objective was to investigate any potential effects of the Slimflex™ Plastic off-the-shelf foot orthosis on foot health related quality of life (QOL) using the Leeds Foot Impact Scale (LFIS) and foot pain using the Visual Analogue Scale (VAS). Plantar foot pressure measurement, walking speed, foot stability during walking and foot kinematics were then investigated to provide a rationale as to why foot health related QOL and foot pain may be affected with the foot orthosis. Data was analysed using SPSS version 16.0. Due to the known potential effects of medication, data was analysed for the total patient group (n=35) and subanalyses were then carried out on the group of patients who presented with stable medication throughout the study (n=12). This enabled any changes to be attributed to the foot orthosis alone and not because of any effects of medication. The LFIS and VAS for foot pain were significantly lower with the use of the foot orthosis over six months (p<0.05). Peak plantar pressure at the forefoot increased between barefoot and shod, and barefoot and foot orthosis (p<0.05), but decreased between shod and foot orthosis (p<0.05). Pressure time integral at the forefoot reduced with the foot orthosis (p<0.05). There was an increase in contact area at the midfoot and in hallux and lesser toe contact area, with the orthosis (p<0.05). Walking speed also increased over the six months (p