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A total of 7 osteoarthritis hip were operated with M2a-Magnum large metal femoral head withBi-Metric XR femoral stem (Biomet). All cases were female with average age 77.6 (range 68-85).The average diameter of the femoral head is 43.7 mm (range 40-48). All acetabular cupswere fixed without any acetabular screws and cups with three spikes were chosen to obtain aninitial rigid fixation on the osteoporotic acetabulum. Acetabular cups of the first 4 cases werefixed by traditional method without fluoroscopy and acetabular cups of the remaining 3 caseswere fixed under fluoroscopy (Figure 1). The maximum gap width between acetubulum andacetabular cup surface were evaluated on antero-posterior X-ray images. Comparison betweenpostoperative acetabular cup position with preoperatively planned ideal cup position wasperformed.RESULTSAll the results are shown in Figure 2. In the first 4 cases with traditional cup fixation, 2 casesdemonstrated a lateral position with 2 mm gap. One case demonstrated 0 mm gap and anotherwith slightly medialized position. In the fluoroscopy group, all 3 cases demonstrated neutralposition with 0 mm gap. No critical complication was observed in all cases.DISCUSSIONAs acetabular cup screw is not available in metal on metal THA system utilizing larger femoralhead, the initial impaction and fixation of the cup is crucial. Particularly in osteoporotic cases, itis often difficult to fix the cup firmly at optimum position due to acetabulum bone fragility. Toreduce the risk of mal-positioning of the acetabular cup, we utilized fluoroscopy whenimpacting the acetabular cup. It is concluded that cup impacting is performed easier and saferunder fluoroscopy especially in the elderly aged osteoporotic patients. While this method isuseful to determine the gap between cup surface and acetabulum, cup anteversion andabduction angles cannot be precisely determined due to pelvic tilting during surgery.FiguresPoster: 97Supracondylar Femoral Fracture After Total Knee Arthroplasty in ElderlyCases*Kei Shiramizu - Nagasaki Nakatsushima Hospital - Tsushima, JapanJunji Maeda - Nagasaki Nakatsushima Hospital - Tsushima, JapanHikaru Saita - Nagasaki Nakatsushima Hospital - Tsushima, Japan*Email: keishiramizu@yahoo.co.jpfile:///E|/ISTA2010-Abstracts.htm[12/7/2011 3:15:47 PM]