Preheating of Femur Component in Hybrid Total Hip Arthroplasty

Background

* Recently published studies confirm that preheating of femoral component enhances shear strength of implant-cement interface. Both Iesaka et al 2003 and Jafri et al 2004 showed reduction in cement porosity on cement-implant interface with preheated femur components. We will use the radiostereometry analysis (RSA) to investigate how the preheating of femur component influence on prosthesis survivorship. There are no clinical controlled studies performed to the date.

The aim of the study

* Comparison of the migration rates between preheated and non-preheated femur components, analyzed with RSA.

Methods

* Randomization of 80 patients into 2 groups with 40 in each. All patients will undergo standard hybrid total hip replacement. In group one the femur component (Bi-Metric, Interlock Biomet) will be preheated to 40 degrees of Celsius before cementation. In group two: the control group, the femur component will be of room temperature. We will measure the temperature at cement bone interface during the operation with use of thermocouple electrodes inserted through separate drill hole in the femur. The measurements will be recorded every 10 seconds. The patients will follow the standard postoperative rehabilitation program. * The RSA analysis will be performed the first day after the operation and at 3, 12, 24 months postoperatively. * The Dual-energy X-ray absorptiometry scanning (DEXA) of the femur will be performed at the first week after the operation and at 12 and 24 months postoperatively. * The patients will be followed both clinically and radiologically at 1 and 2 years after the operation (Harris Hip Score). * The results will be expressed as mean + SD (in mm). ANOVA statistical analysis will be used to confirm the differences between the groups.