Test-Retest Reliability of Acoustic Emission Sensing of the Knee during Physical Tasks

Abstract

Acoustic emission (AE) sensing is an increasingly researched topic in the context of orthopedics and has a potentially high diagnostic value in the non-invasive assessment of joint disorders, such as osteoarthritis and implant loosening. However, a high level of reliability associated with the technology is necessary to make it appropriate for use as a clinical tool. This paper presents a test-retest and intrasession reliability evaluation of AE measurements of the knee during physical tasks: cycling, knee lifts and single-leg squats. Three sessions, each involving eight healthy volunteers were conducted. For the cycling activity, ICCs ranged from 0.538 to 0.901, while the knee lifts and single-leg squats showed poor reliability (ICC < 0.5). Intrasession ICCs ranged from 0.903 to 0.984 for cycling and from 0.600 to 0.901 for the other tasks. The results of this study show that movement consistency across multiple recordings and minimizing the influence of motion artifacts are essential for higher test reliability. It was shown that motion artifact resistant sensor mounting and the use of baseline movements to assess sensor attachment can improve the sensing reliability of AE techniques. Moreover, constrained movements, specifically cycling, show better inter- and intrasession reliability than unconstrained exercises.

Acoustic emissions and age-related changes of the knee

“…The statistical analysis of the data was performed using IBM SPSS Statistics v.28. Since, according to the previous work [11], [19], the AE parameter values were considered to be non-normally distributed, a Mann-Whitney U test was used to compare AEs between the OG and YG. A significance level of p>0.05 was used for all comparisons.…”

“…Three methods of AE hit definition were considered in this study (Table II). The recoding method was based on previous works [11], [12] with the sensor fixed in place using a foam holder and double-sided medical tape on the right medial tibial condyle area [13]. Cycling was used to excite the joint AEs, while avoiding the influence of body mass (e.g., sit-to-stand exercises [14]) or individual differences in exercise execution (e.g.…”

“…Cycling was used to excite the joint AEs, while avoiding the influence of body mass (e.g., sit-to-stand exercises [14]) or individual differences in exercise execution (e.g. knee flexion [11], [15]). Approximately one minute of cycling was carried out for each mode and pace (30 and 60 rpm) was recorded, and then repeated with the second sensor, yielding a total of twelve records for each participant (3 modes x 2 cadences x 2 sensors).…”

“…The thresholds were chosen based on the values previously used in the literature, with 32dB for HF sensor [18] and 36dB for LF sensor [10]. For hits over 1 μs, the mean number of hits per rotation, hit amplitude and duration, time to peak of the hit (rise time), signal strength, and absolute energy were included in the age group comparison, based on the previous work [11], [19]. For the high amplitude hits, the overall number was considered.…”

Non-Invasive Assessment of Cartilage Damage of the Human Knee Using Acoustic Emission Monitoring: A Pilot Cadaver Study

“…For instance, the work by Ozmen et al [31] discusses mounting methods to improve accelerometer sensing performance in the 50 Hz-10 kHz frequency band for sound recordings of the knee. In our previous work [32], [33], we presented a procedure to mitigate motion artefacts and improve the repeatability of AE recordings in the broad frequency range of 20-500 kHz. Finally, different positions for the placement of AE sensors were considered for OA knees [21] and wrist joints of healthy volunteers [30].…”