Abstract
BACKGROUND: The cephalomedullary nail is the most common device used to treat unstable intertrochanteric fractures (ITFs) (AO/OTA 31-A2 and A3) in the geriatric population. However, there is lack of radiological parameter to evaluate the entry point; hence, this study reports a new radiological parameter to evaluate the entry point of the nail. Besides, other risk factors were also examined. METHODS: A retrospective study on the geriatric population with unstable ITFs was conducted from July 2011 to December 2014. A total of 136 patients were enrolled in this study; they received treatment with Gamma-3 nails (Stryker, Mahwah, NJ, USA) and were followed for at least 1 year. Demographic data, radiological parameters, and side-difference of the distance from the piriformis fossa to the greater trochanteric tubercle in the anteroposterior view (dPG) were compared between the union and failure groups. Student's t test, χ test, and multiple logistic regression were used in the statistical analyses. RESULTS: The overall failure rate was 13.23% (18 patients). Sex, tip-apex distance (TAD), and dPG were significantly different between the failure and union groups in multivariate analyses. Using a dPG > 6 mm as a reference, patients with a dPG > 6 mm had an odds ratio of 7.64 for failure relative to a dPG < 6 mm. CONCLUSION: This study provides additional evidence demonstrating that sex and TAD have significant effects on the outcomes of unstable ITFs after nailing. Moreover, the newly reported radiological parameter, dPG, can be used to predict the failure of ITFs treated using cephalomedullary nails.