A dynamic programming approach for automatic stride detection and segmentation in acoustic emission from the knee

Abstract

We study the acquisition and analysis of sounds generated by the knee during walking with particular focus on the effects due to osteoarthritis. Reliable contact instant estimation is essential for stride synchronous analysis. We present a dynamic programming based algorithm for automatic estimation of both the initial contact instants (ICIs) and last contact instants (LCIs) of the foot to the floor. The technique is designed for acoustic signals sensed at the patella of the knee. It uses the phase-slope function to generate a set of candidates and then finds the most likely ones by minimizing a cost function that we define. ICIs are identified with an RMS error of 13.0% for healthy and 14.6% for osteoarthritic knees and LCIs with an RMS error of 16.0% and 17.0% respectively.

Assessment of Hip and Knee Joints and Implants Using Acoustic Emission Monitoring: A Scoping Review

“…Human cadaveric knee specimens with all soft tissues removed except ACL were used in two studies [12], [13]. Studies also examined AEs in relation to non-pathological joint conditions such as mechanical loads during movement [33], joint friction [34], the consistency of subject's joint acoustical signals between measurements [34], [35] and stride detection using AE during walking [36]. Only five studies conducted experiments ex vivo (Supplemental materials: Table III).…”

“…The number of used sensors ranged from one to eight (Supplemental materials: Table V). Similar to the joint assessment in vivo, different movements [44], [49]; 2) lateral side of the knee: [39]; 3) lateral side of the patella: [33], [35], [45]; 4) center of the patella: [11], [36], [46]; 5) medial side of the patella: [33], [45], [51], [52]; 6) medial femur condyle: [11], [38], [44]; 7) lateral tibia condyle: [11], [44], [46]; 8) inferior to patella and anterior to medial patella retinaculum: [37], [40]- [43], [60]; 9) medial tibia condyle: [11], [44], [46]; 10) medial side of the knee: [39]; 11) lateral to patellar tendon: [53]; 12) medial to patellar tendon: [50], [53]. [34] were recorded to produce AEs, and various types of mechanical loads were used in vitro.…”