Association of Long Versus Standard-Length Cephalomedullary Nail Constructs with Posterior Sagging in Intertrochanteric Fractures with Posteromedial Comminution: A Retrospective Comparative Study.

Background: Posterior sagging (PS) of the proximal fragment after cephalomedullary nailing (CMN) of intertrochanteric fractures leads to loss of anteromedial cortical support. Methods: We retrospectively reviewed 118 patients with AO/OTA 31-A2 intertrochanteric fractures (2007 classification). After an institutional protocol change, standard-length constructs with one distal screw were used until March 2019 (n = 65) and long constructs (≥300 mm) with two distal screws from June 2019 (n = 53); the cohorts were consecutive, not concurrent. Results: PS occurred in 23/118 patients (19.5%): 21/65 (32.3%) with standard-length versus 2/53 (3.8%) with long constructs (p < 0.001; adjusted odds ratio (OR) 0.08, 95% confidence interval (CI) 0.02-0.37). With standard-length constructs, PS was more frequent with big lesser trochanteric (LT) fragments (42.9% vs. 13.0%, p = 0.014); the interaction was not significant (p = 0.092). Long-construct use and a higher reduction score were associated with lower odds of PS, and older age and a big LT fragment with higher odds. Greater trochanter (GT) separation was present in 114 of 118 fractures and could not be evaluated as a risk factor. Conclusions: PS was associated with the standard-length construct and, within this group, with a big LT fragment. Nail length, distal locking, and treatment era could not be separated, so these findings show an association, not a causal effect of nail length. Functional outcomes were not assessed.