To evaluate the relationship between a limb-length discrepancy and the clinical and radiological outcomes after bipolar hemiarthroplasty for femur neck fractures in elderly patients.

Between August 2004 and January 2007, 60 out of 80 cases over 65 years who underwent cemented bipolar hemiarthroplasty for femur neck fractures with a more than 2 years follow-up were evaluated retrospectively by dividing the patients into two groups, > 5 mm (group 1) and < 5 mm (group 2) of limblengthening. Harris hip score, the activity of daily living(ADL), dislocation rate, pain by a visual analogue scale (VAS) and acetabular wear by radiographic measurements were analyzed.

For each group, the Harris hip score in group 1 and 2 was 80.0 and 76.2, respectively. The ADL in group 1 and 2 was respectively, 36 and 29 preoperatively, 56 and 52 postoperatively. The visual analogue scale in group 1 and 2 was 3.53 and 2.23 (P=0.002), respectively, and acetabular wear was encountered in 6 and 8 cases in group 1 and 2, respectively. The VAS score was significant. There was no difference in acetabular wear and dislocation between the two groups (P>0.05).

Limb-lengthening by hemiarthroplasty may be a cause of pain but with little effect on the overall functional outcome.