Intraoperative Evaluation of Component Stability in Total Knee Arthroplasty
Information concerning component stability immediately following total knee arthroplasty (TKA) must be reliable. To this end, we developed a measurement system for tibial component, which is thought to be the most frequent loosening component, using three non-contact displacement transducers fixed on the tibial cortex. The measurement system consists of three parts: A device which is connected to the tibial component and has three steel plates, a sensor unit, and an external fixator which connects the sensor unit to the tibial shaft. A load is applied with a push-pull gauge from which a voltage output is supplied to the A–D converter. Sampled data are calculated as displacements by a personal computer that displays the tibial component micromotion data on a cathode ray tube (CRT).
Clinical application of this measurement began in March 1990. Between that date and September 1990, 11 joints in 9 cases were measured. System accuracy is within 10 µm. Even though the measurement takes 10–15 minutes, the quantitative information obtained from this system seems to be useful for the evaluation of the quality of component fixation.
Key wordsTotal knee arthroplasty Quantitative measurement Micromotion Displacement transducer Subsidence and lift-up
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- 2.Albrektsson BE, Ryd L, Carlson LV, Freeman MA, Herberts P, Regner L, Selvik G (1990) The effect of a stem on the tibial component of knee arthroplasty: A roentgen stereophotogrammetric study of uncemented tibial components in the Freeman-Samuelson knee arthroplasty. J Bone Joint Surg [Br] 72: 252–8Google Scholar
- 6.Hvid I (1988) Trabecular bone strength at the knee. Clin Orthop 227: 220–21Google Scholar