German Congress of Orthopaedics and Traumatology (DKOU 2025)
Deutscher Kongress für Orthopädie und Unfallchirurgie 2025 (DKOU 2025)
Implementation of a new cementless total hip arthroplasty stem does not increase variability in femoral head length selection for high-volume surgeons
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Objectives and questions: The selection of femoral head size in total hip arthroplasty (THA) plays a crucial role in achieving optimal joint stability and biomechanics. Recent studies suggest that shorter heads (S/M) are typically preferred to minimize complications associated with longer heads. This study aimed to evaluate whether transitioning from a Corail-like cementless stem to a different system results in greater variability in femoral head length selection during THA for high-volume surgeons.
Material and methods: A retrospective study was conducted on patients who underwent uncemented THA via the Direct Anterior Approach for primary indications between 2021 and 2023 at an academic institution. Patients were categorized based on the stem system used: Group 1 (A familiar Corail-like stem routinely used by the surgeon), Group 2 (first six months following the switch to another system), and Group 3 (subsequent cases after the transition period). The primary outcome was the variance in femoral head length selection across groups. Femoral heads were categorized as short (small or medium, S/M) or long (large, extra-large, or extra-extra-large, L/XL/XXL), and statistical analyses were performed to compare variability across groups.
Results: A total of 289 patients were included in the study. Baseline characteristics did not differ significantly among the three groups (Table 1 [Tab. 1]).
Table 1: Patient demographics Mean (SD); n (%)
The distribution of femoral head sizes was as follows:
Group 1:85 S/M; 28 L/XL/XXL; variance = 0.1881
Group 2:57 S/M; 25 L/XL/XXL; variance = 0.2145
Group 3:73 S/M; 21 L/XL/XXL; variance = 0.1754
Levene’s test p-value:0.454
Levene’s test confirmed no significant difference in variance across groups.
Discussion and conclusions: Transitioning between uncemented stem systems did not result in increased variability in femoral head size selection. Experienced surgeons maintained consistent positioning of the rasp and implant, regardless of the stem system used. These findings suggest that femoral head length selection remains stable when switching between stem systems, reinforcing the reliability of intraoperative decision-making.



