By activating receptors, called pressure sensors, the pressure and distribution of the support of the foot are measured, obtaining an intuitive map in colors, such as the one shown in Figure 1. This image is the plantar footprint, in which that the plantar zones with greater and lesser pressure are described. The signal produced by the activation of the pressure platform sensors is collected and processed by a software and is represented in the form of an image where each pressure value is converted into color.
Figure 1. Example of baropodometry results. Data provided by Ricardo Acevedo.
The lack or excess of support in any region of the sole of the foot generates incorrect, incomplete or incoherent information and causes an alteration in postural balance. Therefore, it is detrimental to the whole body and can be the cause of pain, muscle tension, compensation, etc.
It is a tool commonly used by podiatrists in the assessment of different pathologies such as knee replacement (Notarnicola et al. 2018), osteoporosis (Cultrera et al. 2010), diabetic foot (Anjos et al. 2010), nonspecific low back pain (Pena Junior et al. 2021) and in pregnant women (Valerio et al. 2020).
This test allows analysis of the distribution of forces under each foot when standing or walking. The analysis software calculates the displacements of the center of pressure as well as the spatio-temporal parameters of the gait. It is widely used to test balance stability, dysmetries, rotations at a higher level, muscle contraction imbalances in the tone in standing, etc. During gait analysis, the software provides:
Depending on the map or thermal footprint obtained, a certain alteration of balance will be established, which entails a specific pathological assessment, such as those that we will see in clinical cases. Protocol analysis such as that of Gimenez et al. (2018), demonstrate the effectiveness of this technology in the diagnosis of static and dynamic balance disorders.
At a clinical level, ThermoHuman has extensive experience in the thermographic assessment of foot pathologies, as we show in various publications. Clinical cases such as diabetic foot amputation, plantar fasciitis vs. Baxter's neuropathy and the specific article on thermography and podiatry attest to this. In addition, we have a free class for podiatrists who want to get started with thermography assessment (in Spanish).
Regarding the scientific literature, we will briefly review what has been investigated to date in this regard. In a technical review on foot temperature measurement systems (Grech et al. 2019), the characteristics of various devices were analyzed. It was determined that infrared thermography, by analyzing only static images, can obtain high-quality information related to inflammation pathologies, since they experience hyperthermic behavior.
Undoubtedly, the most studied podiatric pathology due to its relationship with thermographic measurement is pressure ulcers in patients with diabetic foot (Bus et al. 2021; van Netten et al. 2020; Killeen et al. 2020), since intensive and effective use in prevention has been demonstrated and its follow-up is really simple and very responsive to treatment.
In addition, thermography has an interesting relationship with other technologies, as in Rodriguez-Sanz y colaboradores (2019), where they related their findings to those of electromyography in runners with functional clubfoot. For this reason, we expose the scientific evidence and clinical experience that relate thermography and pressure platforms.
As far as the combination of thermography and pressure platform is concerned, and as far as the authors are aware, there is only one individual study (da Silva Alves et al. 2019), which demonstrates a moderate to high correlation between the data of these two technologies, when patients perform the baropodometric test with their eyes open.
According to our clinical experience, podiatric pathologies behave like any other pathology in the musculoskeletal system, having similar thermal behaviors. The thermal response depends, in the same way, on variables such as the type of damaged tissue and the severity of the injury. Thus, a fasciopathy will normally have a hyperthermic behavior and a neurovascular pathology will experience a hypothermic pattern, as described in the article on plantar fasciitis vs. Baxter's neuropathy, where thermography allowed a key differential assessment in the resolution of the clinical case. We present below two clinical cases, courtesy of Ricardo Acevedo from Podiatech.
A patient (woman, 48 years old, 56 kg, physically active recreational athlete) came to the consultation due to subluxation syndrome of the second toe of the right foot with pain under the 2nd metatarsal head and paresthetic sensations and vague pain in the 3rd to 5th toes. radiating proximally.
Figure 2. Static and dynamic analysis of the patient's plantar pressures. Data provided by Ricardo Acevedo.
As we can see in figure 2, the static pressure platform determines an advancement of the center of gravity of the right foot (possible contraction of the triceps surae). There is no pressure on the isthmus in either foot, but there is a considerable increase in the anterior load, with the maximum pressure in the right forefoot, in addition to a greater load-bearing surface. This leads us to have an initial suspicion of simple metatarsalgia due to weight overload.
In the dynamic analysis a curiosity is revealed regarding the right foot: the pressure lines and
of forces are diverted, with the vertical forces being carried from the heel to the fifth metatarsal and from there to all the affected areas, while the average pressure circulates through the most medialized area
of the foot This entails forces that shear with divergent lines. Generally, these signs
They are not usually compatible with metatarsalgia.
Figure 3. Thermograms and avatars of 3 consecutive sessions, where the diagnosis is aided and the efficacy of the treatment is verified. The graph that shows the decrease in the TRI metric is also included. Data provided by Ricardo Acevedo.
We performed thermograms to investigate a little further, which can be seen in figure 3. The thermography reveals a Thermal Risk Index (TRI) of 100/100, where we found a very high degree of hypothermia in the affected foot. , right in the zone of shear forces and the zone of maximum pressure. These findings are consistent with a neuritis possibly leading to a Morton's neuroma. In a third time, we verified a Morton's neuroma with ultrasound. The treatment with plantar supports normalized the thermograms as we see in the TRI curve.
Unfortunately, the subluxation-neuroma combination made treatment difficult and the pain factor was very difficult to control (due to a multitude of other factors), so neuroma surgery could be a definitive solution to be able to treat the subluxation alone. Even so, he continues to do his sports activities, being curious that it hurts more when he leaves them and "just" walks.
The data obtained through the measurement of plantar pressures, both static and dynamic, provide very valuable information on the functionality of the foot in various aspects and in various situations. It is not surprising, therefore, that there is an evident relationship between the differences in the plantar footprint between the right and left foot (pressure asymmetries) and the differences in the thermography of the regions of interest of the soles (thermal asymmetries). Lastly, and as shown by clinical experience, these asymmetries are closely related to the severity of the injuries and the risk of injury. For this reason, the resulting combination of technologies plays a key role in the prevention and injury follow-up, both from a clinical point of view and from a high sports performance point of view.
Anjos DM, Gomes LP, Sampaio LM, Correa JC, Oliveira CS. Assessment of plantar pressure and balance in patients with diabetes. Arch Med Sci. 2010 Mar 1;6(1):43-8.
Bus SA, Aan de Stegge WB, van Baal JG, Busch-Westbroek TE, Nollet F, van Netten JJ. Effectiveness of at-home skin temperature monitoring in reducing the incidence of foot ulcer recurrence in people with diabetes: a multicenter randomized controlled trial (DIATEMP). BMJ Open Diabetes Res Care. 2021 Sep;9(1):e002392.
Cultrera P, Pratelli E, Petrai V, Postiglione M, Zambelan G, Pasquetti P. Evaluation with stabilometric platform of balance disorders in osteoporosis patients. A proposal for a diagnostic protocol. Clin Cases Miner Bone Metab. 2010 May;7(2):123-5.
da Silva Alves R, Iunes DH, Pereira IC, Borges JBC, Prado Mariano KO, Carvalho LC. Correlation Between the Trajectory of the Center of Pressure and Thermography of Cancer Patients Undergoing Chemotherapy. J Chiropr Med. 2019 Sep;18(3):180-187.
Gimenez FV, Stadnik AMW, Maldaner M. Analyses of Baropodometry Protocols Through Bibliometric Research. Annu Int Conf IEEE Eng Med Biol Soc. 2018 Jul;2018:3882-3885.
Grech J, Mizzi S, Falzon O. A Technical Review of Foot Temperature Measurement Systems. J Am Podiatr Med Assoc. 2022 Feb 25:1-42. doi: 10.7547/21-065. Epub ahead of print. PMID: 35239503.
Killeen AL, Brock KM, Dancho JF, Walters JL. Remote Temperature Monitoring in Patients With Visual Impairment Due to Diabetes Mellitus: A Proposed Improvement to Current Standard of Care for Prevention of Diabetic Foot Ulcers. J Diabetes Sci Technol. 2020 Jan;14(1):37-45.
Notarnicola A, Maccagnano G, Fiore A, Spinarelli A, Montenegro L, Paoloni M, Pastore F, Tafuri S, Moretti B. Baropodometry on patients after total knee arthroplasty. Musculoskelet Surg. 2018 Aug;102(2):129-137.
Pena Junior PM, de Sá Ferreira A, Telles G, Lemos T, Calazans Nogueira LA. Concurrent validation of the center of pressure displacement analyzed by baropodometry in patients with chronic non-specific low back pain during functional tasks. J Bodyw Mov Ther. 2021 Oct;28:489-495.
Rodriguez-Sanz D, Losa-Iglesias ME, Becerro-de-Bengoa-Vallejo R, Dorgham HAA, Benito-de-Pedro M, San-Antolín M, Mazoteras-Pardo V, Calvo-Lobo C. Thermography related to electromyography in runners with functional equinus condition after running. Phys Ther Sport. 2019 Nov;40:193-196.
Valerio PM, Gonçalves VE, Zordão CC, Rezende MS, Moisés ECD, Guirro ECO. Influence of type 1 diabetes on the postural control of women in the third gestational trimester. Clin Biomech (Bristol, Avon). 2020 Jul;77:105062.
van Netten JJ, Raspovic A, Lavery LA, Monteiro-Soares M, Rasmussen A, Sacco ICN, Bus SA. Prevention of foot ulcers in the at-risk patient with diabetes: a systematic review. Diabetes Metab Res Rev. 2020 Mar;36 Suppl 1:e3270.
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ThermoHuman has had the support of the Funds of the European Union and the Community of Madrid through the Operational Programme on Youth Employment. Likewise, ThermoHuman within the framework of the Export Initiation Program of ICEX NEXT, had the support of ICEX and the co-financing of the European Regional Development Fund (ERDF).
Thermohuman has received funding from the Centre for the Development of Industrial Technology (CDTI), in participation with the European Regional Development Fund (ERDF), for the R+D activities involved in creating a new tool, based on thermography, for the prediction and prevention of rheumatoid arthritis. See project detail.
