December 29, 2025
2 min read
Key takeaways:
- Collared fully hydroxyapatite-coated femoral components had a rate of early periprosthetic femoral fracture of 0.11%.
- In comparison, flat-tapered wedge designs had a rate of 0.72%.
Results showed collared fully hydroxyapatite-coated femoral components had lower rates of postoperative periprosthetic femoral fractures but higher rates of intraoperative periprosthetic femoral fractures vs. flat-tapered wedge designs.
“Propensity score matching revealed that the incidence of early [postoperative periprosthetic femoral fractures] was significantly lower in collared fully [hydroxyapatite]-coated femoral components than in flat-tapered wedge femoral components,” Rui Hirasawa, MD, PhD, assistant professor in the department of orthopedic surgery of the Graduate School of Medicine, Chiba University, Japan, and colleagues wrote in the study.
Data were derived from Hirasawa R, et al. Bone Joint J. 2025;doi:10.1302/0301-620X.107B10.BJJ-2024-1494.R1.
The authors added, “Surprisingly, [intraoperative periprosthetic femoral fractures] were more frequent in collared fully [hydroxyapatite]-coated femoral components than in flat-tapered wedge femoral components.”
Hirasawa and colleagues propensity score matched patients who underwent total hip arthroplasty with the direct anterior approach and a flat-tapered wedge component (n = 1,804) 1:1 to those who received a collared fully hydroxyapatite-coated component (n = 1,804). Researchers compared the incidence of early postoperative periprosthetic femoral fracture as well as the incidence of intraoperative periprosthetic femoral fracture between the two implant designs.
Results showed 0.11% of patients who received a collared fully hydroxyapatite-coated component experienced early postoperative periprosthetic femoral fracture compared with 0.72% of patients who received a flat-tapered wedge component.
Hirasawa and colleagues found a median time to early postoperative periprosthetic femoral fracture of 10 days with injury mechanism absent in 73% of cases. Two of the early postoperative periprosthetic femoral fractures were Vancouver classification type A(G) and one was type A(L), according to researchers. Hirasawa and colleagues also found 33% of early periprosthetic femoral fractures were B1 fractures and 47% were B2 fractures. Results showed 33%, 53% and 13% of postoperative periprosthetic femoral fractures were treated with conservative management, osteosynthesis and revision surgery, respectively.
Hirasawa and colleagues found intraoperative periprosthetic femoral fractures occurred in 3.49% of patients with collared fully hydroxyapatite-coated components vs. 2% of patients with flat-tapered wedge components.
“These findings highlight the importance of femoral component design, including broaching, in THA implant selection for postoperative periprosthetic femoral fracture and intraoperative periprosthetic femoral fracture,” Hirasawa and colleagues wrote.
For more information:
Rui Hirasawa, MD, can be reached at r.hirasawa1221@me.com.
Perspective
This study by Rui Hirasawa, MD, PhD, and colleagues adds to the growing body of literature showing that cementless, triple-tapered collared (TTC) stems have significantly lowered periprosthetic fracture rates. Combining this data with the ease of use, especially from anterior based approaches, explains the rapid growth of this stem class in the American Joint Replacement Registry (AJRR) within the past several years. The TTC stem not only reduces fracture rates but also appears to have a very low rate of aseptic loosening. The 7-year revision rates in the AJRR with the TTC stem is the lowest of any reported product. Most manufacturers now offer a TTC stem, widening access for patients. Careful follow-up of each stem will be important to verify this finding across products.
No implant is without a potential downside, and I have observed two potential pitfalls with the TTC implant. The first is removal. Once fully osteointegrated, this implant can be challenging to remove as it can ingrow and ongrow to the tip of the stem. Surgeons should be prepared with all femoral revision exposure principles, including cutting off the collar and an opening osteotomy, to safely remove the stem. The second is the collar. While it is clear to me the collar helps prevent periprosthetic fracture, there is some concern that collar overhang could lead to soft tissue irritation. While no published data currently exists to support this argument, further research in this arena is warranted.
William G. Hamilton, MD
Disclosures: Hamilton reports being a consultant for and in product development with DePuy Synthes, Onkos Surgical and Total Joint Orthopedics; and designer of the Actis hip stem from DePuy Synthes.
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