Safer Hip Implant Design Prevents Early Femoral Fractures

Femoral fractures remain one of the most serious complications after total hip replacement (THR)—a surgery performed about one million times each year worldwide to relieve pain and restore mobility. These fractures, which occur near the artificial hip joint, are the leading cause of reoperation following THR, with nearly half occurring within the first 90 days after surgery. Now, a new study has identified a hip implant design that reduces early fracture risk after THR.

To better understand how implant design influences fracture risk after THR, researchers from the Graduate School of Medicine at Chiba University (Chiba, Japan) conducted a large-scale retrospective study comparing the two most common types of femoral stems used in THR: collared fully hydroxyapatite (HA)-coated stems and flat-tapered wedge stems.

The study analyzed 4,511 THR cases performed by a single surgeon between 2009 and 2023. Using propensity score matching, the team compared 1,804 patients with collared HA-coated stems to an equal number with flat-tapered wedge stems, ensuring balanced groups by age, sex, body mass index, and underlying conditions such as osteoarthritis.

The findings, published in The Bone & Joint Journal, showed a significantly lower rate of early postoperative femoral fractures among patients receiving collared HA-coated stems—only two cases compared to 13 cases in the flat-tapered wedge group. However, intraoperative fractures occurred slightly more often in the collared HA-coated stem group, underscoring the need for refined surgical techniques to mitigate this risk.

“Our results have the potential to directly improve patient safety and surgical outcomes in THR by helping surgeons make more informed implant selections, leading to fewer serious complications, faster functional recovery, and reduced need for reoperation,” said Assistant Professor Rui Hirasawa, the study’s lead author. “In the long term, this research may set a new global standard for femoral stem selection in hip replacement.”

Related Link:
Chiba University Graduate School of Medicine