One-stage bilateral versus unilateral short-stem total hip arthroplasty: comparison of migration patterns using...

The hypothesis of this study was that femoral implant migration would not differ between simultaneous bilateral or unilateral short-stem THA.

Implant migration of 202 femoral short-stems (100 unilateral and 102 one-stage bilateral cases) in 151 patients was assessed by "Ein-Bild-Roentgen-Analysis Femoral-Component-Analysis" in a two years follow-up (2.0-3.0 years). Migration patterns of unilateral and simultaneous cases were analysed and compared.

There was no difference between the two groups regarding age, body mass index and gender. After two years mean subsidence of all 202 implants was 1.43 mm (-6.5 mm to 2.0 mm). After initial subsidence of 0.37 mm per month within the first six weeks, the mean monthly migration was reduced to 0.02 mm between one and two years post-operative. There was no statistical difference in mean migration between unilateral (1.34 mm) and simultaneous bilateral (1.51 mm) THA (p = 0.33).

In summary, two years post-operative there was no difference in the amount of mean implant subsidence between unilateral compared to simultaneous bilateral short-stem THA. This suggests that regarding implant fixation simultaneous bilateral short-stem THA is as safe and successful as a solely unilateral intervention.