FEMORAL COMPONENT REVISION WITH USE OF IMPACTION BONE GRAFTING

Abstract

Revision of the femur component in total hip arthroplasty using impaction bone grafting (IBG) was performed in 140 hips of 136 patients in our hospital. The mean age of the patients at the time of the femoral component revision was 72 years. The median of follow-up time was 80 months. 140 hips were operated with use of YU stem (Yamagata university stem, collared, not polished)104, Exeter stem 2, CPT 2, Restration 5, and others 27.

The length of the stem was a regular stem 114, a long stem 26. The complications related to the revised hip consist of infection 5, dislocation 8, DVT9, fracture during operation 11. Four stems were revised due to infection and two due to loosening.

YU stem is made of titanium alloy with collar, the surface of that stem is not polished and Ra is 0.27 μm. We started to apply IBG in 1994, there were no IBG instrument set and system available such as Exeter, CPT in Japan, so we had used YU stem. However, the result with YU stem was preferable and the implant was stable. Thus, we have been using YU stem. In the process, there have been a number of improvements in IBG instrument and system since we started using them. At first, all medullar cavity is filled with grafted bone up to proximal entry with moderate impaction. Along with guide pin, new medullar canal is made by drilling and insert stem tamper into the space to tighten the layer of impaction, then cement fixation of the stem is performed. This method made the operative time short and operative technique easy.

There are several advantages of IBG technique we used. In revision THA, we can revise the stem with the same length of previous one again and exchange also a long stem to a regular length stem. In addition, the system make it possible to re-construct the case of distal medullar canal excessively filled with bone cement below stem, by digging about around 2 cm distally without need to remove all the cement. Severe bone atrophy and fragile of femur is also reconstructed by IBG.

Impaction bone grafting technique with modified system has great merit to recover bone stock and to obtain implant stability after femoral reconstruction of revision surgery.