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

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: rGroningen = 0.995, ralg25 = 0.919 and ralg29 = 0.680).

CONCLUSION: The temperature sensor is a valid instrument to measure footwear use and non-use when using the Groningen algorithm.