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.