Background: In revision total hip arthroplasty, intraoperative split
fractures and cortical perforation fractures are becoming a more common
concern with the increasing use of diaphyseal fitting cementless stems. The
purpose of this study was to evaluate the risk factors and frequency of
intraoperative fractures with the use of these stems and their effect on
radiographic and functional outcomes.
Methods: We performed a retrospective case-control study of 211
consecutive patients who had undergone revision hip arthroplasty with a
diaphyseal fitting cementless stem between December 1998 and March 2002.
Sixty-four patients sustained an intraoperative fracture of the femur. One
hundred and fifteen patients were followed for a minimum of two years;
function was analyzed with self-administered outcome questionnaires, and
radiographs were evaluated for evidence of bone ingrowth into the femoral
stem.
Results: Risk factors associated with an intraoperative fracture
were a substantial degree of preoperative bone loss, a low femoral
cortex-to-canal ratio, underreaming of the cortex, and the use of a
large-diameter stem. The majority of the diaphyseal undisplaced linear
fractures occurred at the distal end of an extended trochanteric osteotomy
during stem insertion. Fracture due to cortical perforation occurred most
often during cement removal. These intraoperative fractures had no significant
effect on the functional outcome or radiographic evidence of bone
ingrowth.
Conclusions: There was a surprisingly high rate of intraoperative
femoral fractures associated with the use of a diaphyseal fitting stem in
revision total hip arthroplasty. Identification of risk factors such as
preoperative bone loss and a low cortex-to-canal ratio may permit planning to
avoid such fractures. However, the final functional and radiographic outcomes
appear to have been unaffected by the fracture when it had been managed
appropriately.
Level of Evidence: Prognostic study, Level II-1
(retrospective cohort study). See Instructions to Authors for a complete
description of levels of evidence.