Response to the Letter to the Editor regarding “Reduced periprosthetic fracture rate for a cemented anatomical versus a tapered polished stem in hip arthroplasty: A 6-year follow-up of a prospective observational cohort study”

Abstract

We appreciate the interest shown by Drs. Wahl and Gautier in our recent publication and thank them for their thoughtful comments and critical reading of our work.

We acknowledge the inversion of colours in Figure 1 and appreciate the authors' attention to this detail. We agree that a corrigendum should be issued to clarify that the orange curve corresponds to the polished tapered stem (PTS) and the blue curve to the anatomical stem (AS).

The concern raised about potential confounding due to surgical technique is valid and warrants discussion. However, we respectfully disagree that intraoperative errors or technical shortcomings primarily explain our findings. First, our study was conducted at a single high-volume university-affiliated centre, where both stem types were implanted by experienced orthopaedic surgeons using standardised protocols. Importantly, the transition from PTS to AS was a deliberate department-wide change, accompanied by training to ensure continuity and consistency of technique. Second, while the pattern of early periprosthetic fractures in the PTS group may resemble that seen with uncemented stems, this pattern is consistent with prior literature reporting higher early PFF rates in force-closed polished tapered designs in frail populations. These findings have been replicated in multiple registry studies and observational cohorts, and our study adds mid-term follow-up confirmation to this established trend. Third, the suggestion that aggressive broaching or specific technical challenges contributed to early PFFs is mainly speculative. Both stem designs were implanted in patients with similar baseline characteristics, and the transition was not associated with any significant increase in complications during the learning curve period.

We note the concern about the higher observed PJI rate in the PTS group. While the PJI rate exceeded 1% in both groups, it remained within the expected range for a frail hip fracture population with advanced age and comorbidities. Notably, the AS group had a lower PJI and dislocation rate despite the potential for surgical adaptation during the transition, supporting the robustness of the findings.

We agree that our findings should not be extrapolated to all force-closed stems, nor to other settings without careful consideration. Our conclusions are based on the specific stem models used and the population studied. However, as others have shown, including the registry study cited by Drs. Wahl and Gautier, CPT stems have been associated with a higher fracture risk than their Exeter counterparts, underscoring the importance of implant selection even within design classes.

We welcome this opportunity to further clarify our findings and reiterate that while surgical technique is always important, the evidence in our study supports the conclusion that stem design plays a critical role in the risk of periprosthetic fracture.

Sincerely,

Anna Josefsson, Michael Axenhus, Raéd Itayem, Sebastian Mukka, Martin Magnéli (On behalf of all authors).