PurposeDespite optimal surgical intervention, patients with femoral shaft fractures often report functional limitations, pain, and an overall reduction in their quality of life. The clinical objective of the FLiP pilot trial was to determine whether patient positioning during femur fixation influences postoperative femoral alignment and associated health outcomes. This secondary analysis aimed to identify demographic and surgical factors associated with health-related quality of life and functional outcomes in FLiP trial participants using data from the EuroQol-5 Dimensions 5-Level (EQ-5D-5L) visual analog scale (VAS), EQ-5D-5L Function, and modified Harris Hip Score (mHHS).MethodsWe conducted three linear repeated measure mixed models to determine factors associated with the EuroQol-5 Dimensions (EQ-5D-5L) visual analog scale (VAS), EQ-5D-5L Function, and modified Harris Hip Score (mHHS) over 6-week, 3-month, and 6-month postoperative fixation. Results were presented as adjusted mean differences (AMDs), 95% confidence intervals (CIs), and p-values.ResultsA total of 96 participants were included in this secondary analysis. The mean age was 61.8 years (SD 26.1), and 51 (53.1%) participants were female. Most participants had a proximal third diaphysis fracture (65.3%), followed by a mid-diaphyseal fracture (33.7%), and a distal third diaphysis fracture (1.0%), with subtrochanteric fractures present in 59 (61.5%) participants. A higher Injury Severity Score (ISS) was associated with a lower EQ-5D-5L VAS score (AMD −0.78, 95% CI −1.44 to −0.11; p = 0.04), indicating a worse health status. Open fractures (n = 3) were associated with lower EQ-5D-5L Function scores compared to closed fractures (AMD −0.26, 95% CI −0.45 to −0.067; p = 0.01), indicating worse function. No factors were found to be significantly associated with mHHS.ConclusionsThese results highlight the importance of injury severity within the context of patient health-related quality of life and demonstrate that regardless of the quality of fracture fixation, participants may experience a slower recovery due to sustaining multiple injuries. These findings offer valuable prognostic information for surgeons to share with patients who have more severe injuries.Trial RegistrationClinicalTrials.gov NCT0386280.