72 Osrečki, Burger / Rehabilitacija - letn. VII, supl. 3 (2008) IN-SHOE PRESSURE MEASUREMENT K. Osrečki and H. Burger K. Osrečki and H. Burger Institute for Rehabilitation, Ljubljana, Slovenia Institute for Rehabilitation, Ljubljana, Slovenia present study the F-Scan was used on 430 patients. In most patients, plantar pressure were satisfactorily reduced with new orthopaedic shoes. The authors believe that in-shoe plantar pressure measurement is much more important at the time of the fitting of new shoes when it objectively dem- onstrates the results. When pressures are not distributed well, additional adaptations can be made to decrease them. Abstract Patients with foot problems are frequent visitors of outpa- tient clinics specializing in physical medicine and reha- bilitation. Specialists in PMR may rely on their clinical examination or use additional assessment methods, such as in-shoe plantar measurements. For the purpose of the INTRODUCTION Patients with foot problems are frequent visitors of outpatient clinics specializing in physical medicine and rehabilitation. Specialists may rely on their clinical examination or use additional assessment methods. The clinical exam is very effective in accurate evaluation of anatomical abnormalities, however, it is not as effective in evaluation of functional abnormalities (1). Functional abnormalities are especially difficult to evaluate under loading conditions, particularly in shoes. In the western world people seldom walk barefoot, so it is important for clinicians to assess the processes inside the shoes. Various platforms may be used for barefoot-walking assessment, while insoles with measurement sensors are needed for in-shoe measurement . In-shoe plantar pressure can be measured with a variety of instruments, including force-sensing resistors or FSRs, piezoelectric sensors (in hydrocells) and capacitive trans- ducers, as well as by critical light deflection (2). These instruments can be used as discrete sensors or they create a matrix of multiple sensors. In discrete measurements, the sensors are positioned at specific anatomical locations only, whereas at matrix meas- urements, the sensors are organized in rows and columns and are located under the whole sole. Each method has its advantages and disadvantages and it is important for clini- cians to beawareofthesystem’smeasurementproperties. The aim of the study was to find out whether in-shoe plantar pressure measurement was necessary before prescription or whether it was more important at the fitting of new shoes. METHODS AND SUBJECTS Methods In-shoe plantar pressures were measured by the F-Scan system (Tekscan, Boston, MA). The system consists of 0.18mm-thick sensor insoles, which have pressure-sensi- tive, resistive, and conductive silver-based inks arranged in 60 columns and 21 rows embedded in Mylar coating. The columns and rows intersect, creating a “cell”. There are 960 cells in each insole. The resistance et each cell is proportional to the pressure applied on its surface. These insoles are connected to cuff units (preamplifiers), which are attached to the lower leg with a Velcro strap. A 9.25m cable attaches the sensor and cuff unit to computer. The data were collected at 50 Hz. The F-scan has excellent resolution and provides reliable measures of relative pres- sure values (3, 4). In all the patients, the measurements were performed twice, at their first visit before prescription and after the fitting of the new shoes. Subjects Subjects The study included all the patients who were examined at the Institute for Rehabilitation, Republic of Slovenia, at the outpatient clinic for foot problems, from January 1st 2003 to March 31st 2005, and for whom their phyisician believed that they needed in-shoe pressure measurement at examina- tion or at fitting. RESULTS 430 patients, 51.4% percent of them were women, were included into the study. They were 58 years old on aver- age (sd 18 years, from 18 -90 years). They had from one to four different diagnoses. 70.9% had orthopaedic problems, 13.5% diabetes, 6.0% rheumatoid arthritis, 10.1% paresis and different neurological diseases. 52.8% were measured at the examination only, 15.1% at the fit- ting only and 32.1% at the examination and at the fitting (Figure 1). 73 Figure 1: Percentage of patients, examined in different years, measured at examination only, at fitting only or at examination and fitting Table 1 presents the characteristics of prescribed orthopaedic shoes for patients with different diagnoses. Table 1: Characteristics of prescribed shoes for patients with different diagnoses Orthopaedic impairments Diabetes Rheumatoid Rheumatoid arthritis arthritis Neurological problems High shoes High shoes 38.6 53.4 42.3 75.0 Custom-made insole Custom-made insole 23.6 56.8 19.6 75.0 Lateral wedge Lateral wedge 10.8 17 .2 12.5 37 .5 Medial wedge Medial wedge 7 .5 6.8 3.8 37 .5 Arch supports Arch supports 70.8 41.3 61.5 25.0 Elevation Elevation 1 1.8 6.8 0 25.0 Soft material Soft material 56.0 68.0 61.0 50.0 Shoe adaptations successfully decreased excessive plantar pressures in 72.8 % of patients (Figure 2). Figure 2: Percentage of patients with excessive plantar pressures at examination and at fitting DISCUSSION The study found a high level of agreement between medical diagnosis and prescribed characteristics of orthopaedic shoes. The results do not clearly demonstrate how often diagnosis and prescription were actually based on in-shoe plantar meas- urements and how often on clinical examination only. However, Figure 1 shows that in the first year in over 60% of the subjects plantar pressures were measured at the examina- tion only, whereas in the last year only in one third of the patients pressures were still measured at the examination only while in over half of them they were measured at both, the examination and the fitting. It seems that we had realised that the measurements were not needed so much for diag- nosis and prescription, but more for the evaluation of new shoes. That is in agreement with Ahroni (4) who states that high in-shoe pressure in diabetic subjects can be predicted in part from readily available clinical characteristics. Additionaly, the study found that with new shoes elevated plantar pressures was satisfactorily reduced in over 70% of the subjects (Figure 2). Only 12.5% of the subjects still had excessive plantar pressures in more than one area and 14.7% in one area only. At the examination only 6.6% of the patients did not have excessive plantar pressures, while 73.5% had excessive plantar pressures in more than one area. The measurements objectively demonstrated the reduction of pressures and additional adjustments were made to reduce them in those patients who still had excessive pressures. CONCLUSION In-shoe measurement of plantar pressures may be helpful at examination, but it is much more important at the time of the fitting of new shoes when it objectively demonstrates the result. When the pressures are not distributed well, additional adaptations can be made to decrease them. R References eferences: 1. Imamura M, Imamura ST, Salomão O, Pereira CAM, De Carcalho AE, Neto RB. Pedobarometric evaluation of the normal adult male foot. Foot Ankle Int 2002; 23: 804-9. 2. Smith KE, Commean PK, Mueller MJ, Robertson DD, Pilgram T, Johnson J. Assessment of the diabetic foot using spiral computed tomography imaging and plantar pressure measurements: a technical report. J Rehabil Res Develop 2000; 37: 31-40. 3. Randolph AL, Nelson M, Akkapeddi S, Levin A. Reli- ability of measurements of pressure applied on the foot during walking by a computerized insole sensor system. Arch Phys Med Rehabil 2000; 81: 573-8. 4. Ahroni JH, Boyko EJ, Forsberg RC. Clinical Correlates of plantar pressure among diabetic veterans. Diabetic Care 1999; 22: 965-72. 113 15 44 84 27 48 30 23 44 0% 20% 40% 60% 80% 100% Percentage of patients 2003 2004 2005 Examination Fitting Both 6,6 72,8 19,9 14,7 35,3 9,6 29,4 2,2 8,8 0,7 0 10 20 30 40 50 60 70 80 Percentageof patients 01234 No.ofareaswithexcessivepresure Examination Fitting Osrečki, Burger / Rehabilitacija - letn. VII, supl. 3 (2008)