A computational method to differentiate rheumatoid arthritis patients using thermography data.

BACKGROUND: The traditional rheumatoid arthritis (RA) diagnosis is very complicated because it uses many clinical and image data. Therefore, there is a need to develop a new method for diagnosing RA using a consolidated set of blood analysis and thermography data. OBJECTIVE: The following issues related to RA are discussed: 1) Which clinical data are significant in the primary diagnosis of RA? 2) What parameters from thermograms should be used to differentiate patients with RA from the healthy? 3) Can artificial neural networks (ANN) differentiate patients with RA from the healthy? METHODS: The dataset was composed of clinical and thermal data from 65 randomly selected patients with RA and 104 healthy subjects. Firstly, the univariate logistic regression model was proposed in order to find significant predictors. Next, the feedforward neural network model was used. The dataset was divided into the training set (75% of data) and the test set (25% of data). The Broyden-Fletcher-Goldfarb-Shanno (BFGS) and non-linear logistic function to transformation nodes in the output layer were used for training. Finally, the 10 fold Cross-Validation was used to assess the predictive performance of the ANN model and to judge how it performs. RESULT: The training set consisted of the temperature of all fingers, patient age, BMI, erythrocyte sedimentation rate, C-reactive protein and White Blood Cells (10 parameters in total). High level of sensitivity and specificity was obtained at 81.25% and 100%, respectively. The accuracy was 92.86%. CONCLUSIONS: This methodology suggests that the thermography data can be considered in addition to the currently available tools for screening, diagnosis, monitoring of disease progression.

Nanomechanical Properties of Articular Cartilage Due to the PRP Injection in Experimental Osteoarthritis in Rabbits.

The purpose of this study was twofold. Firstly, we proposed a measurement protocol for the atomic force microscopy (AFM) method to determine the nanomechanical properties of articular cartilage in experimental osteoarthritis in rabbits. Then, we verified if mechanical properties can be evaluated with AFM shortly after platelet-rich plasma (PRP) injection. We hypothesized that the modulus determined by AFM indentation experiments could be utilized as a progressive disease marker during the treatment of osteoarthritis. The rabbits were equally divided into three groups of six: control (group 1); injections of saline (0.5 mL) and 10% surgical talc (Talcum Pharmaceutical®, Minsk, Belarus) were delivered into the right knee under the patella (group 2 and 3); and PRP was injected into the right knee (group 3). In group 2, the arithmetic average of absolute values (Ra) change was a 25% increase; the maximum peak height (Rp) increased by over 102%, while the mean spacing between local peaks (S) increased by 28% (p < 0.05). In group 3, Ra increased by 14% and Rp increased by 32%, while S decreased by 75% (p < 0.05). The Young's modulus of the surface layers decreased by 18% as a result of induced model of osteoarthritis (IMO) (p < 0.05), and it increased by 9% (p < 0.05) as a result of PRP therapy, which means that the mechanical properties of cartilage were partially recovered. This research demonstrates that Young's modulus utilized on a nanometer scale has potential to be a progressive disease marker during the treatment of osteoarthritis.

AFM-Based Method for Measurement of Normal and Osteoarthritic Human Articular Cartilage Surface Roughness.

In osteoarthrosis, pathological features of articular cartilage are associated with degeneration and nanomechanical changes. The aim of this paper is to show that indentation-atomic force microscopy can monitor wear-related biomechanical changes in the hip joint of patients with osteoarthritis. Fifty patients (N = 50), aged 40 to 65, were included in the study. The mechanical properties and the submicron surface morphology of hyaline cartilage were investigated using atomic force microscopy. Measurements of the roughness parameters of cartilage surfaces were performed, including the arithmetic average of absolute values (Ra), the maximum peak height (Rp), and the mean spacing between local peaks (S). The arithmetic mean of the absolute values of the height of healthy cartilage was 86 nm, while wear began at Ra = 73 nm. The maximum changes of values of the roughness parameters differed from the healthy ones by 71%, 80%, and 51% for Ra, Rp, and S, respectively. Young's modulus for healthy cartilage surfaces ranged from 1.7 to 0.5 MPa. For the three stages of cartilage wear, Young's modulus increased, and then it approached the maximum value and decreased. AFM seems to be a powerful tool for surface analysis of biological samples as it enables indentation measurements in addition to imaging.

Infrared Thermography Sensor for Disease Activity Detection in Rheumatoid Arthritis Patients.

A recent review of thermography studies in rheumatoid arthritis shows limited data about disease activity and mostly focuses on differences between the thermography of rheumatoid arthritis patients and typical subjects. A retrospective study compared patients with high disease activity (n = 50), moderate disease activity (n = 16), and healthy participants (n = 42), taking into account demographic, clinical, laboratory, and thermography parameters. We applied an infrared thermography sensor and a fingers examination protocol. Outcomes included the mean temperature of five fingers of a hand: In static, post-cooling, post-rewarming, the total change in mean temperature of fingers due to cold provocation, the total change in mean temperature of fingers due to rewarming, the area under the cooling curve, the area under the heating curve, the difference between the area under the rewarming and the cooling curve, and temperature intensity distribution maps. For patients with high disease activity, a lower area under the heating curve and a lower difference between the area under the rewarming curve and the cooling curve were observed, as well as a smaller total change in mean temperature due to rewarming, compared to patients with moderate disease activity (p < 0.05). Our study findings could be helpful in patients with an equivocal clinical examination.

Correction of Planovalgus Deformity Through Rotational Reinsertion of the Lateral Layers of the Achilles Tendons in Ambulatory Children With Cerebral Palsy.

Symptomatic planovalgus deformity is a condition commonly seen in patients with cerebral palsy. The authors propose a new procedure for the management of this deformity through rotational reinsertion of the lateral layers of the Achilles tendon, and then they assess its benefit by comparing plantar pressure distribution patterns in children preoperatively and at 6- and 12-month intervals postoperatively. Pedobarographic measurements, range of motion of the ankle, and radiographic indexes were used to assess the outcome of the surgery. The functional abilities of the patients were assessed based on the Gross Motor Function Classification System. A total of 37 feet (22 patients) were included, with a mean ± standard deviation age at surgery of 11.8 ± 2.7 (range 9.1 to 14.5) years. All feet were managed through rotational reinsertion of the lateral layers of the Achilles tendon. Surgical correction of planovalgus has good outcomes. Significant changes were observed with statistical significance at the 5% (p ≤ .05) level in plantar pressure distribution in children preoperatively and at 6- and 12-month intervals postoperatively. The results show that the proposed method of surgery is effective in the correction of planovalgus in ambulatory children with cerebral palsy.

Ensembling rules in automatic analysis of pressure on plantar surface in children with pes planovalgus.

PURPOSE: This paper presents a method of ensembling rules obtained through induction of several basic types of decision trees. MATERIAL AND METHODS: The proposed method uses rules generated by means of well-known decision trees: CART, CHAID, exhaustive CHAID and C4.5. The method was tested on data describing pressure distribution under foot during gait in children with pes planovalgus (PV) and typical foot. Children with pes planovalgus underwent surgical intervention and were re-examined. Overall, 316 gait cycles have been used in analysis. RESULTS: The obtained results consist of a set of rules for all considered cases and show that the proposed method may be a useful tool of gait analysis on the basis of parameters that have a physical interpretation. CONCLUSIONS: The presented method for mining rules useful in this respect may be successfully used by persons with a typically medical knowledge and could improve the understanding of the human gait phenomenon. There is obviously no reason why this method could not be used in the case of other data as well.

Research of the spatial-temporal gait parameters and pressure characteristic in spastic diplegia children.

PURPOSE: Spastic diplegia is the most common form of cerebral palsy. It presents with symmetric involvement of the lower limbs and upper limbs. Children with spastic diplegia frequently experience problems with motor control, spasticity, and balance which lead to gait abnormalities. The aim of this study is twofold. Firstly, to determine the differences in spatial-temporal gait parameters and magnitude of plantar pressure distribution between children with spastic diplegia (CP) and typical children. Secondly, to compare and evaluate main changes of plantar pressure and spatial-temporal gait parameters instead of data between spastic diplegia children with prescribed ankle - solid foot orthosis (AFOs) and without using AFOs. METHODS: The evaluation was carried out on 20 spastic diplegia children and 10 agematched children as a control group aged 6-15 years. Twenty children with spastic diplegia CP were divided into two groups: ten subjects with prescribed AFOs and ten subjects without use of assistive device. Patients used the AFOs orthosis for one year. Measurements included in-shoe plantar pressure distribution and spatial-temporal gait parameters. RESULTS: Spatial-temporal gait parameters showed meaningful difference between study groups in velocity, stride length, step length and cadence ( p < 0.05). However no significant differences between patients with and without AFOs were found ( p > 0.05). Significant differences between typical and spastic diplegia children with AFOs were observed in the magnitude of plantar pressure under the toes, the metatarsal heads, the medial arch, and the heel ( p < 0.05). For typical subjects, the highest pressure amplitudes were found under the heel and the metatarsal heads, while the lowest pressure distribution was under the medial arch. In CP patients the lateral arch was strongly unloaded. The peak pressure under heel was shifted inside. CONCLUSIONS: Collected data and calculated scores present a state of the gait in test groups, showed the difference and could be valuable for physicians in decision making by choosing qualitative therapy. Furthermore, it allows predicting probability of further possible changes in gait of spastic diplegia patients with AFOs and without it. In conclusion, our current results showed that the use of AFOs, prescribed on a clinical basis by doctors improves gait patterns and gait stability in children with spastic cerebral palsy.

Assessing plantar pressure distribution in children with flatfoot arch: application of the Clarke angle.

BACKGROUND: Flatfoot, or pes planus, is one of the most common foot posture problems in children that may lead to lower-extremity pain owing to a potential increase in plantar pressure. First, we compared plantar pressure distribution between children with and without flatfoot. Second, we examined the reliability and accuracy of a simple metric for characterization of foot posture: the Clarke angle. Third, we proposed a mathematical model to predict plantar pressure magnitude under the medial arch using body mass and the Clarke angle. METHODS: Sixty children with flatfoot and 33 aged-matched controls were recruited. Measurements included in-shoe plantar pressure distribution, ground reaction force, Clarke angle, and radiography assessment. The measured Clarke angle was compared with radiographic measurements, and its test-retest reliability was determined. A mathematical model was fitted to predict plantar pressure distribution under the medial arch using easy-to-measure variables (body mass and the Clarke angle). RESULTS: A high correlation was observed between the Clarke angle and radiography measurements (r > 0.9; P < 10(-6)). Excellent between- and within-day test-retest reliability for Clarke angle measurement (intraclass correlation coefficient, >0.9) was observed. Results also suggest that pressure magnitude under the medial arch can be estimated using the Clarke angle and body mass (R(2) = 0.95; error, <0.04 N/cm(2) [2%]). CONCLUSIONS: This study suggests that the Clarke angle is a practical, reliable, and sensitive metric for quantification of medial arch height in children and could be recommended for research and clinical applications. It can also be used to estimate plantar pressure under the medial arch, which, in turn, may assist in the timely intervention and prognosis of prospective problems associated with flatfoot posture.

Analysis of the plantar pressure distribution in children with foot deformities.

This paper describes the method of measuring and assessing the pressure distribution under typical feet and the feet of patients with deformities such as: planovalgus, clubfoot, and pes planus using a pedobarograph. Foot pressure distribution was measured during static and walking at individual normal walking speed. Time-series pressure measurements for all sensors were grouped into five anatomical areas of human foot. In typical subjects, the heel was the first part of the foot receiving the loading of the body. Then it moved to the toe through the midfoot and the metatarsal area. The highest mean pressure in typical subjects was found under the heel and the metatarsal heads. The lowest pressure distribution was under the cuboid bone. In the planovalgus subjects, a higher pressure distribution was found under cuboid bone compared to typical one. In the pes cavus subjects, the pressure distribution was lower under all parts of foot. In the clubfoot subjects, the pressure distribution, the contact area of each mask, and the time of foot contact area in left and right foot are respectively different.