PREDICTORS OF ADVERSE EVENTS FOLLOWING INTRAMEDULLARY AND EXTRAMEDULLARY FIXATION OF TROCHANTERIC HIP FRACTURES

We previously presented the results of a randomized trial (RCT) that suggested ambulatory patients with trochanteric fractures managed with intramedullary nails (IMN) have similar one-year outcomes to extramedullary sliding hip screw (SHS) fixation. However, a large proportion of patients experienced medical- and device-related adverse events postoperatively, regardless of implant type. We aimed to identify predictors of adverse events following trochanteric hip fracture fixation. We used data collected from a completed RCT for these analyses. The INSITE trial included ambulatory patients 18 years and older with trochanteric fractures. We used multivariable logistic regression to identify independent predictors of adverse events up to 52-weeks postoperative, while controlling for covariables. Adverse events (AE) included any medical occurrence, not necessarily related to the treatment, while serious adverse events (SAE) included those that prolonged patients' hospital stay, resulted in persistence disability, life-threatening illness or injury, or death, and were unrelated to the device. Device-related adverse events (DAE) were those likely related to the implant. For this analysis we excluded patients who did not receive the implant they were allocated to receive. We stratified these analyses by implant type to determine if predictors of adverse events differed in patients managed with an IMN vs. SHS. We included 714 patients in this analysis (369 who underwent IMN fixation, and 345 who underwent SHS fixation). A total of 182 patients experienced an AE (25.5%), 173 an SAE (24.2%), and 42 a DAE (5.9%). The proportion of patients who experienced AEs were not significantly different based on implant type. In the IMN group, patients who were admitted from an institution or home with care (vs. those living at home independently) were more likely to experience both an AE (odds ratio [OR] 1.84, [1.03–3.30]), and an SAE (OR 3.06 [1.70–5.53]). Similarly, patients in the IMN group who had an American Society of Anaesthesiologists (ASA) class of 3 or 4 (vs. 1 or 2) were more likely to experience an AE (OR 2.06 [1.15–3.70]) and SAE (OR 3.26 [1.75–6.06]). We found similar associations in the IMN group for patients with heart or kidney comorbidities. Previous fracture was we significantly associated with DAEs in the IMN group (OR 3.02 [1.05–8.72]). In the SHS group, patients with a concomitant injury were more likely to experience both an AE (OR 2.54 [1.05–6.14]), and SAE (OR 2.38 [1.03–5.49]) In addition, patients in the SHS group with anemia were more likely to experience an AE (OR 3.04 [1.39–7.20]), while those with hypertension were more likely to experience an SAE (OR 1.98 [1.01–3.89]). Increased body mass index was significantly associated with DAE in the SHS group (OR 1.09 [1.01–1.17]). This data suggest that patients who are more frail or dependent may be more likely to experience morbidity following IMN fixation of trochanteric fractures, and thus may be more suited to SHS fixation. Alternatively, patients with concomitant injuries managed with SHS fixation may be more likely to experience AEs or SAEs postoperatively. However, additional research is required to conclusively determine which trochanteric fracture patient sub-groups are ideally suited to each implant.