High incidence of stem loosening in association with periprosthetic femur fractures in previously well-fixed cementless grit-blasted tapered-wedge stems.

PURPOSE: Periprosthetic femur fracture is a potentially worrisome phenomenon for cementless stem fixation. The aim of this study was to document the incidence of stem loosening following periprosthetic femur fracture in previously well-fixed cementless grit-blasted tapered-wedge stems.

METHODS: We identified 36 periprosthetic femur fractures of either Vancouver B1 or B2 following hip arthroplasties using cementless grit-blasted tapered-wedge titanium stems at three participating institutions (GB group). The control group consisted of 21 periprosthetic femur fractures of either Vancouver B1 or B2 following hip arthroplasties using cementless proximal porous-coated stems at the same institutions during the same period of study (PC group). All femoral stems had been in a well-fixed state before occurrence of fracture. All patients were treated surgically and femoral stem stability was assessed using preoperative radiographs and confirmed by intraoperative scrutinization.

RESULTS: Seven (19.4%) of 36 fractures were Vancouver B1 and 29 (80.6%) were Vancouver B2 in the GB group, whereas 18 (85.7%) of 21 fractures were Vancouver B1 and 3 (14.3%) were Vancouver B2 in the PC group (P < 0.0001). The odds ratio for stem loosening was 24.86 (95% CI, 5.69-108.63) in the GB group versus the PC group.

CONCLUSIONS: Hip arthroplasty using cementless grit-blasted tapered-wedge titanium stems showed higher incidence of stem loosening in association with periprosthetic femur fracture than hip arthroplasty conducted using proximal porous-coated stems. A high index of suspicion of stem loosening might be necessary in periprosthetic femur fracture following hip arthroplasty using this type of stems.