Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025;45(1):113-120.

Radiographic Performance of a Novel Femoral Stem Design

Jacob Hawkins  1 , Emilie N Miley  2   3 , Kendyll Coxen  4 , Catalina Baez  5 , Justin T Deen  6 , Chancellor F Gray  6 , Hernan A Prieto  5 , Luis Pulido  6 , Hari K Parvataneni  6
Affiliations

Radiographic Performance of a Novel Femoral Stem Design

Jacob Hawkins et al. Iowa Orthop J. 2025.

Abstract

Background: In the United States, cementless fixation is the gold standard for elective total hip arthroplasty (THA). Many modern cementless stem designs have re-introduced collared stem options in recent years which have demonstrated a lower risk of fracture. Minimal studies, however, outline radiographic performance of this novel stem design. As such, the primary purpose of this single-center study was to determine the radiographic performance, including defining patterns of radiographic incorporation and remodeling, associated with this novel, single stem design.

Methods: Data within the institutional data repository was queried for patients who underwent a primary or conversion THA between January 1st, 2016 and July 31st, 2022. Patients were included in the study if they were 18 years of age or older and had a minimum of a one-year follow-up visit. Patients were excluded if they did not have a radiograph at the one-year follow-up or if the stem was placed in a revision setting. Continuous data were reported as means and standard deviations (± SD), and categorical data were reported as number of cases (n) and percentages (%).

Results: A total of 592 encounters (562 patients) were included in the final analyses. At the one-year postoperative visit, no stems met the criteria for radiographic loosening, 502 (85.2%) patients had distinct radiographic osseointegration of their stem as defined by at least one radiographic spot weld. There was an 18.7% incidence of calcar-collar gaps on initial radiographs and 66.7% of these filled in by one-year. The intraoperative fracture rate was 0.7% without any cases of secondary stem revision or loosening and only 0.8% of stems showed subsidence (i.e., all less than 5 mm) without loosening or revision. Thigh pain within the first year was reported in 1.7% of patients. The all-cause stem revision at one-year was 0.2%.

Conclusion: This study demonstrated excellent rates of healing of this novel stem design. Additionally, this novel stem was associated with low rates of periprosthetic fracture, stem revision, and thigh pain. Level of Evidence: IV.

Keywords: collared femoral stem; total hip arthroplasty; uncemented femoral stem.

PubMed Disclaimer

Conflict of interest statement

Disclosures: The authors report no potential conflicts of interest related to this study.

Figures

Figure 1A to 1B.
Figure 1A to 1B.
(1A) Calcar Gap evident on immediate postoperative radiograph, (1B) Osseointegration with filling in of the Calcar gap and osseointegration in Gruen zone 7 by one-year postoperatively.
Figure 2.
Figure 2.
ACTIS® Femoral Stem showing osseointegration in Gruen Zones 1, 2, 6 and 7 including integration of the collar. Bony integration is favorable for loading and force transfer through the proximal bone.
Figure 3.
Figure 3.
Radiographic spot weld in Gruen Zone 1.
Figure 4.
Figure 4.
Radiographic neocortex formation in Gruen Zones 3 and 4.
Figure 5.
Figure 5.
Radiographic lucency in Gruen Zone 4.
See this image and copyright information in PMC

References

    1. Siddiqi A, Levine BR, Springer BD. Highlights of the 2021 american joint replacement registry annual report. Arthroplasty Today. 2022;13:205–207. doi: 10.1016/j.artd.2022.01.020. doi: - DOI - PMC - PubMed
    1. Herrera A, Mateo J, Gil-Albarova J, et al. Cementless hydroxyapatite coated hip prostheses. Biomed Res Int. 2015;2015:386461. doi: 10.1155/2015/386461. doi: - DOI - PMC - PubMed
    1. Kiran M, Johnston LR, Sripada S, Mcleod GG, Jariwala AC. Cemented total hip replacement in patients under 55 years. Acta Orthop. 2018;89(2):152155. doi: 10.1080/17453674.2018.1427320. doi: - DOI - PMC - PubMed
    1. Khanuja HS, Vakil JJ, Goddard MS, Mont MA. Cementless femoral fixation in total hip arthroplasty. J Bone Joint Surg Am. 2011;93(5):500–509. doi: 10.2106/JBJS.J.00774. doi: - DOI - PubMed
    1. Crawford DA, Berend KR. Reduction of periprosthetic proximal femur fracture in direct anterior total hip according to stem design. Orthop Clin North Am. 2021;52(4):297–304. doi: 10.1016/j.ocl.2021.05.002. doi: - DOI - PubMed

LinkOut - more resources