Validity and feasibility of a temperature sensor for measuring use and non-use of orthopaedic footwear

Abstract

LAY ABSTRACTOrthopaedic footwear is frequently prescribed to patients with a wide variety of pathologies, such as diabetes mellitus, rheumatoid arthritis, degenerative foot disorders and muscle disorders. For these patients, orthopaedic footwear is used for a range of serious foot and/or ankle problems; for example, to prevent the onset or recurrence of foot ulcers, to reduce pain, to support anatomical foot deformities, enhance stability and mobility, and redistribute plantar pressure. Orthopaedic footwear is only effective if they are used. To date, the use of orthopaedic footwear has mostly been assessed using questionnaires, interviews or diaries. However, these methods are not objective and lack accuracy. Temperature measurement can be used to determine the use of orthopaedic footwear. This study uses a new temperature sensor to objectively monitor use and non-use of orthopaedic footwear. Ten healthy participants were monitored over a period of 48 h using the sensor in their footwear. Footwear use based on the sensor data was compared with the reference standard, a camera attached to the footwear. The study found that the temperature sensor is a valid instrument to measure footwear use and non-use.Objective: Adherence is a prerequisite for the effectiveness of orthopaedic footwear. The aim of this study is to assess the validity of a new temperature sensor for objective assessment of footwear use and non-use. Design: Observational study. Methods: The validity of a temperature sensor (Orthotimer, Balingen, Germany) to discriminate between time periods of use and non-use of footwear over a period of 48 h was assessed using 3 algorithms, in 10 healthy participants (mean age 32.8 years (standard deviation (SD) 14.1 years)). Footwear use measured with the sensor was compared with a reference standard, footwear use measured with a time-lapse sports camera secured to the shoe. Main outcome measure: Hours of footwear use. Results: Mean footwear use measured with the camera was 8.10 (SD 2.46) h per day. Mean footwear uses measured with the sensor and calculated with the 3 algorithms were 8.16 (SD 2.37), 8.86 (SD 2.48) and 4.91 (SD 3.17) h per day for the Groningen algorithm, algorithm-25, and algorithm-29, respectively. The correlation between footwear use assessed with the camera and with the sensor was: r Groningen = 0.995, r alg25 = 0.919 and r alg29 = 0.680). Conclusion: The temperature sensor is a valid instrument to measure footwear use and non-use when using the Groningen algorithm.

Leveraging smart technologies to improve the management of diabetic foot ulcers and extend ulcer‐free days in remission

“…Bus el al introduced and validated a temperature‐based monitoring system called “@monitor”, which could be attached to the inner surface of an assistive device (eg, footwear) to determine duration of the use of the assistive device. Orthotimer sensor (Rollerwerk, Balingen, Germany) is an example of commercially available technologies, which is using a microsensor and a unique individual ID number. The sensor could be integrated in shoes, insoles, orthotic devices, and offloading and enables wear time to be measured.…”

“…Bus el al 37 introduced and validated a temperature-based monitoring system called "@monitor", which could be attached to the inner surface of an assistive device (eg, footwear) to determine duration of the use of the assistive device. Orthotimer sensor (Rollerwerk, Balingen, Germany) 38 defined as daily hours of device wear, was determined using sensor data and patient questionnaires. They concluded that a real-time and comprehensive foot pressure alert method with a minimum number of alerts (one every 2 hours) are effective to allow optimal response to offloading cues from a smart insole system and for improving adherence to prescribed diabetic shoes over time.…”

Prevention of foot ulcers in the at‐risk patient with diabetes: a systematic review

“…More research on this topic is needed, to better understand how adherence to wearing therapeutic footwear can be improved. In these studies, adherence should be quantitatively monitored …”

The Potential Role of Sensors, Wearables and Telehealth in the Remote Management of Diabetes-Related Foot Disease

“…A previous study showed that a temperature threshold of 25 • C to indicate that footwear was worn had a sensitivity of 95%, a specificity of 99%, a negative predictive value of 99% and a positive predictive value of 99% in determining footwear use [51]. Past research also demonstrates that these temperature sensors are a valid method of estimating footwear adherence compared to adherence measured using a time-lapse camera [52]. It is anticipated that small sensors will soon become available that can accurately monitor an individual's footwear use and activity and provide "live" data seamlessly to remotely located health practitioners [53].…”

“…Further developments are needed before this approach can be implemented in a remote management program. It should be noted that there is a paucity of commercially available sensors for monitoring adherence easily and accurately, and most of the aforementioned sensors have only been used in a research context [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ].…”