Acetabular Bone Preservation in H1 Ceramic Hip Resurfacing: A Comparison With A Conventional Metal-on-Metal Hip...

This study compared the volume of acetabular bone resection between an anatomically designed cementless ceramic-on-ceramic hip resurfacing arthroplasty (H1HR) and metal-on-metal hip resurfacing (Birmingham Hip Resurfacing; BHR). We hypothesized that the anatomical design of the H1 cup would reduce the need for medialization to avoid rim overhang, thereby preserving acetabular bone stock. A retrospective three-dimensional simulation study was performed in 12 hips with osteoarthritis and femoral head size ≥ 48 mm. H1HR and BHR were virtually implanted using 3D planning software to minimize the risk of groin pain. The primary outcome was the volume of acetabular bone resection. Secondary outcomes included the position of the cup relative to the native hip centre and the cup non-coverage ratio. H1 cups required a mean volume of acetabular bone resection of 11 cm³, while BHR cups required 17 cm³. This 35% reduction was statistically significant. H1 cups had less medialization (-1 mm vs. -6 mm), superior displacement (-1 mm vs. -2 mm), and posterior displacement (-1 mm vs. -3 mm). The mean cup non-coverage ratio was not significantly different (10% vs. 8%). The anatomically designed H1HR achieved a significant 35% reduction in acetabular bone resection compared with BHR. This substantial volume of bone preservation was primarily attributed to the design enabling cup placement with minimal medialization, without increasing the cup non-coverage ratio. Although further validation in cadaveric or postoperative imaging studies is needed, H1 may be a promising option for bone preservation, particularly for young, active patients who might require future revision surgery.