Reliability of lateral wall-thickness measurement in trochanteric fractures and parameters associated with lateral wall integrity

Background The AO Foundation/Orthopaedic Trauma Association (AO/OTA) introduced a new trochanteric fracture classification in January 2018, concerning the lateral wall integrity. It suggested the intramedullary nail fixation in patients with an incompetent lateral wall fracture. Objective To determine the reliability of lateral wall-thickness measurement and the fracture parameters associated with lateral wall integrity. Methods This retrospective study evaluated patients with an intertrochanteric fracture who had had surgery in King Chulalongkorn Memorial Hospital between January 2014 and January 2019. The lateral wall was measured by anteroposterior plain radiography by four raters, two times each. The demographic data and fracture parameters were assessed and compared with respect to lateral wall integrity. Result In a total of 236 femurs and 232 patients having the 2018 AO/OTA-specified 31A1 and 31A2 intertrochanteric fractures, the lateral wall-thickness measurement showed excellent inter-rater reliability at 0.944 (0.927-0.957) and good-to-excellent intra-rater reliability ranging from 0.835 to 0.972. The parameters associated with lateral wall incompetence as per the multivariate logistic regression analysis were fracture angle (odds ratio [OR] = 0.95), distal greater trochanter involvement (OR = 9.47), and fragments at the intertrochanter area (OR = 4.49) and at the lesser trochanter (OR = 2.6). Conclusion Some of the parameters related to trochanteric fractures are associated with lateral wall incompetence. Lateral wall-thickness measurement is a reproducible method, which has been suggested for use by the AO/OTA 2018 classification. It is easy to use and can help select the appropriate treatment for intertrochanteric fracture patients.