Comparison of Cross-Table and Lauenstein Lateral Views for Tip Apex Distance Measurement in Trochanteric Fracture Fixation

Background Tip apex distance (TAD) is a commonly used radiographic index to evaluate the risk of mechanical failure following internal fixation of trochanteric femoral fractures. While the cross-table lateral view (C view) is typically used to assess TAD, Lauenstein’s I view (L view), which approximates the true lateral view, may also allow for reliable measurement. However, the consistency of TAD measurements across different lateral projections has not been fully investigated.

We conducted a retrospective cohort study of patients who underwent internal fixation with a short femoral nail for trochanteric fractures between July 2016 and January 2020. Patients who had both C view and L view radiographs postoperatively were included. TAD was measured on each view and compared using paired t-tests. Pearson’s correlation coefficient was calculated, and agreement was evaluated using Bland–Altman analysis.

A total of 31 patients were included. The mean TAD was 8.55 mm (SD, 2.40; 95% CI, 7.62–9.48) in the C view and 9.63 mm (SD, 3.34; 95% CI, 8.41–10.84) in the L view, with a statistically significant mean difference of 1.06 mm (p = 0.027; 95% CI, 0.13–2.03). A moderate positive correlation was observed between the two views (r = 0.637, p < 0.001). Bland–Altman analysis showed good agreement between the two measurements.

Although a statistically significant difference in TAD measurements was observed between C view and L view, the correlation and agreement were relatively high. These findings suggest that L view may serve as a practical alternative when obtaining the C view is not feasible. Further studies are warranted to confirm these results and evaluate their clinical implications. Competing Interest Statement The authors have declared no competing interest. Funding Statement The author(s) received no specific funding for this work. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Not Applicable The details of the IRB/oversight body that provided approval or exemption for the research described are given below: No I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Not Applicable I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Not Applicable I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Not Applicable Data Availability All relevant data are within the manuscript. Additional datasets generated and analyzed during the current study are available from the corresponding author upon reasonable request.