A self-powered telemetry system to estimate the postoperative instability of a knee implant.
Estimating in vivo the life span of a total knee replacement prosthesis is currently done by estimating the polyethylene (PE) wear rate from measurement of the femorotibial distance using X-ray photographies. This efficient method requires, however, waiting for few years to obtain a readout. This letter proposes using another metric that can be obtained within a couple of months of surgery, namely the center of pressure (COP). This metric represents the point, where the axial force applies the most onto the tibial tray. The displacement of the COP with respect to its ideal position can be used to estimate the wear and the life span of the PE. This requires the implant to be fitted with a telemetry system described briefly. The proposed method is supported by measures and simulations.
Lahuec
Cyril
C
TELECOM Bretagne, CNRS Lab-STICC UMR 3192, Brest, Brittany 29238, France. cyril.lahuec@telecom-bretagne.eu
Almouahed
Shaban
S
Arzel
Matthieu
M
Gupta
Deepak
D
Hamitouche
Chafiaa
C
Jézéquel
Michel
M
Stindel
Eric
E
Roux
Christian
C
D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000379:methods; D003198:Computer Simulation; D019544:Equipment Failure Analysis / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D007720:Knee Prosthesis; D008962:Models, Theoretical; D011312:Pressure; D013686:Telemetry / Q000295:instrumentation*