Restoration of hip geometry after Total Hip Arthroplasty: retrospective comparison of two short stems and one straight stem
Background / Problem Accurate restoration of native hip geometry is a critical objective in total hip arthroplasty (THA) to optimize biomechanics, muscle function, and implant longevity. While short-stem femoral prostheses have gained popularity, their ability to precisely reconstruct key parameters like femoral offset compared to conventional straight stems remains debated. Furthermore, it is often assumed that implant systems with a greater number of size and version options facilitate more accurate anatomical reconstruction.
Objective of the Article This retrospective study aimed to compare the accuracy of hip geometry reconstruction following THA using three different cementless femoral stem designs: two short-stem systems (ANA.NOVA® Proxy and Optimys®) and one conventional straight-stem system (Corail®), which offer a varying number of implant options.
Key Points / Core Message The study analyzed preoperative and postoperative radiographs of 251 patients. Key geometric parameters, including centrum-collum-diaphysis (CCD) angle, femoral offset, and acetabular offset, were measured. While all three implant groups demonstrated a postoperative increase in CCD angle and a decrease in acetabular offset, significant differences were observed in offset restoration. The ANA.NOVA® Proxy short stem (12 options) resulted in the smallest change in femoral offset (mean increase of 1.6 mm), which was significantly less than the Optimys® short stem (24 options; 4.1 mm) and the Corail® straight stem (76 options; 4.9 mm).
Conclusion / Implications for Practice The ANA.NOVA® Proxy short stem enabled a more accurate reconstruction of femoral offset compared to the other evaluated short and straight stems, despite offering the fewest implant options. These findings suggest that a greater number of implant versions does not inherently guarantee superior restoration of hip geometry. A well-designed, single-type short stem can achieve a reliable and precise anatomical reconstruction, challenging the paradigm that more options lead to better outcomes.
