Ultrasonic Procedure for Detecting Prosthesis Loosening
Abstract
Due to increasingly ageing populations and a rising demand on quality of life hip replacement became one of the most common operations in orthopedics and trauma surgery over the last decades and even continues to gain importance. However, in more than 10 percent of cases, loosening of the implanted prosthesis occurs within the first 15 years after surgical implantation. As a result, the prosthesis usually has to be completely replaced in a complex operation which often leads to complications. The later the prosthesis loosening is detected, the more difficult the initial situation for a successful and complication-free prosthesis replacement is. In addition to early diagnosis, it is essential to distinguish between purely mechanical (aseptic) loosening and loosening caused by bacterial infection (septic). Due to a lack of accuracy, conventional diagnostic methods such as projection radiography cannot reliably diagnose loosening in its early stages or detect whether it is associated with the formation of a biofilm in the bone-implant interface.
In this work, we developed a non-invasive ultrasound-based measurement procedure for quantifying the thickness of the layer between the bone and the stem of a hip prosthesis as a correlate to loosening. In principle, it also allows for material characterization of the interface.
The introduced method is based on a well-known analytical model of the reflection of sound waves in a three-layer system being mainly used for characterizing the thickness of thin lubricant films. For the desired medical application of characterizing the bone-implant interface which comes along with rough surfaces, inhomogeneous materials and the impossiblity of reference measurements, we adapted and extended this model and developed suitable data processing algorithms for analyzing the interface.
With respect to determining the layer thickness, the procedure was experimentally validated at different idealized test systems and a more realistic bone-implant system within in the range of approx. 200 µm to 2 mm. Consequently, our procedure is able to quantify the thickness of thin interlayers even at rough, porous and inhomogeneous materials and without a reference measurement.
After further optimization and adaptation, as well as further experimental tests, the procedure offers great potential to significantly improve the diagnosis of prosthesis loosening at an early stage and may also bei applicable to detect the formation of a biofilm.
Mehr zum Titel
| Titel | Ultrasonic Procedure for Detecting Prosthesis Loosening |
|---|---|
| Medien | Talk, MedtecSUMMIT, Nuremberg, 2023 |
| Verfasser | M.Eng. Jan Lützelberger |
| Veröffentlichungsdatum | 2023-05-25 |
| Zitation | Lützelberger, Jan (2023): Ultrasonic Procedure for Detecting Prosthesis Loosening. Talk, MedtecSUMMIT, Nuremberg, 2023. |