Is Nail–Canal Diameter Discordance a Risk Factor for the Excessive Sliding of Cephalomedullary Nails in Geriatric Intertrochanteric Fracture Surgery?

Background and Objectives:: There were limited studies which investigated nail diameter as a predictor for cephalomedullary nail (CMN) failure in intertrochanteric fracture (ITF). We aimed to evaluate the surgical outcomes of CMN in fragility ITF following nail–canal (N–C) diameter discordance. Materials and Methods: From November 2010 to March 2022, we retrospectively reviewed 120 consecutive patients who underwent CMN surgeries due to fragility ITF. We included patients with acceptable reduction and a tip–apex distance ≤ 25 mm. The N–C diameter differences both in anterior–posterior (AP) and lateral-view X-rays were measured, and we compared the number of excessive sliding instances and the rate of implant failure between the N–C concordance (≤3 mm) and discordance (>3 mm) group. Simple linear regression was used to determine the strength of the relationship between the N–C difference and sliding distance. Results: The sliding distance showed no differences between the groups in the AP (3.6 vs. 3.3 mm, p = 0.75) and lateral view (3.5 vs. 3.4 mm, p = 0.91). For analyses in the AP view, the AP-concordance and AP-discordance groups had 14 (25%) and 14 patients (22%) with a sliding distance of >5 mm (p = 0.69), while treatment failure occurred in 3 (5%) and 3 (3%) patients, respectively (p = 0.66). For analyses in the lateral view, the lat-concordance and lat-discordance groups had 8 (27%) and 20 patients (22%) with a sliding distance of >5 mm (p = 0.62), while treatment failure occurred in 1 (3%) and 4 (4%) patients, respectively (p = 1.00). Linear regression analyses showed that the N–C difference in either views was not a significant predictor of sliding distance in both the AP (R(2) = 0.002, p = 0.60) and lateral views (R(2) = 0.007, p = 0.35). Conclusions: If appropriate fracture reduction and fixation are achieved, the N–C discordance of short CMN does not affect treatment outcomes in ITF.