Knee Implant Loosening Detection: A Vibration Analysis Investigation

Abstract

Knee implant loosening is mainly caused by the weakness of the prosthesis-bone interface and is the main reason for surgical revisions. However, pre-operative diagnosis is difficult due to lack of accurate tests. In this study, we developed a vibration-based system to detect the loosening of the tibial implant of an instrumented knee prosthesis. The proposed system includes an instrumented vibrator for transcutaneous stimulation of the bone in a repeatable manner, and accelerometer sensors integrated into the implants to measure the propagated vibration. A coherence-based detection technique was proposed to distinguish the loosened implants from the secure ones. Fourteen ex vivo lower limbs were used, on which the knee prosthesis was implanted, and harmonic-forced vibration was applied on the tibia. The input–output coherence measure provided 92.26% accuracy, a high sensitivity (91.67%) and specificity (92.86%). This technique was benchmarked against power spectrum based analysis of the propagated vibration to the implant. In particular, loosening detection based on new peak appearance, peak shift, and peak flattening in power spectra showed inferior performance to the proposed coherence-based technique. As such, application of vibration on our instrumented knee prosthesis together with input–output coherence analysis enabled us to distinguish the secure from loose implants.

Altering the Course of Technologies to Monitor Loosening States of Endoprosthetic Implants

“…The most sensitive band was found to be above 1500 Hz. (T1-C5) Arami et al [50] also provided a technology to detect loosening states of tibial knee implants.…”

“…The loose implant (in red) can be characterized (by comparison with the fixed, in blue) by an increase in the resonance frequency and by the appearance of harmonics in the output signal. Adapted from the work in[50] under the Creative Commons Attribution 4.0 International License: http://creativecommons.org/licenses/by/4.0/.…”

A New Diagnostic Technique to Detect Early Migration of Joint Prostheses

“…every 6 or 12 months). However, detection of early stages of loosening are ambiguous and can be subjective due to low specificity and accuracy [13,14]. This limits the use of X-ray techniques in detecting early loosening, although it is considered the gold standard in confirming implant loosening.…”

A Vibrational Technique for In Vitro Intraoperative Prosthesis Fixation Monitoring

“…In recent years, non-imaging techniques in the framework of vibrational analysis of the bone-prosthesis system (also known as vibrometry, modal analysis, etc.) have been developed for intraoperative fixation evaluation [5], [7], [11], [15]- [19], osseointegration assessment [20]- [23], and postoperative loosening diagnosis [24]- [32]. Development of instrumented (sensorintegrated) prostheses [22], [27], [28], [33], [34] with telemetric systems for in vivo monitoring [35], [36], establishment of new techniques based on acoustics [23], [34], use of ultrasound probes instead of conventional sensors like accelerometers [30], and extracorporeal shockwave excitation [31] are amongst the recent efforts towards the vibrational analysis of the boneprosthesis systems.…”

“…In most of previous studies the bone-prosthesis system was excited over a narrow frequency band (e.g., <1 kHz [25], [26], 0.1-1.2 kHz [24], 0.1-1.5 kHz [30], 1.2-2 kHz [17], [19], 0.1-2 kHz [29], and 0.03-3 kHz [32]). However, the most sensitive band for excitation was found above 4 kHz during the insertion of prosthesis in a THA [11], and between 12 and 15 kHz for the shoulder joint [18].…”