According to previous gait analyses, insertion of a total hip arthroplasty (THA) will improve the range of hip flexion-extension but not to normal. Use of short stems could have a potential to improve the motion by preservation of more bone and muscular attachments. We evaluated whether a short femoral stem resulted in improved hip motion compared to a conventional stem in patients who underwent 1-stage bilateral THA. The most painful hip was randomised to either design and the 2
Gait analysis was performed with an optical tracking system in 22 patients. The follow-up was performed 1 and 2 years after the operation. The mean age was 59 (SD 7.7) years and body mass index was 27.7 (SD 4.3). 66 subjects without hip pathology served as controls.
Minimal differences were observed, between or within the 2 different stem designs during gait at the 2 follow-up occasions. Comparison between each of the 2 stem designs and controls at 2 years revealed reduced stride length (p = 0.009), cadence, hip extension (p<0.001) and hip extension-flexion range (p = 0.021) for both designs. Furthermore, the range of hip adduction-abduction (p = 0.046) and hip abduction moment for both designs in the frontal plane was also reduced bilaterally (p<0.001).
We found no difference in gait parameters between the short and the conventional stem after 1-stage bilateral THA. Although both hip joints were operated at the same time motions and moments did not normalise after bilateral 1-stage operations.