Similar 2 year migration patterns for a shortened and a distally reduced stem design in uncemented total hip arthroplasty: a randomized controlled trial using radiostereometric analysis.

Study Summary

50 patients with end-stage hip osteoarthritis were randomized to receive either a shortened Microplasty femoral stem or a standard-length Reduced Distal femoral stem during minimally invasive anterior-supine-intermuscular (MIS-ASI) total hip arthroplasty (THA). The primary outcomes were femoral stem subsidence and retroversion at 2 years, assessed using radiostereometric analysis (RSA). Secondary outcomes included additional stem migration patterns, patient-reported outcome measures (PROMs), clinical and radiographic outcomes, and adverse events. Outcomes were assessed at 6 weeks, 1 year, and 2 years postoperatively. Overall, the results revealed no statistically significant differences in subsidence or retroversion between stem designs at 2 years, although the Reduced Distal stem demonstrated greater posterior tilting. Both stems exhibited initial migration within 6 weeks followed by stabilization through 2 years. These findings suggested that both femoral stem designs provided comparable early fixation stability following MIS-ASI THA.