Fracture table vs. lateral positioning for intramedullary fixation of femur fractures (The FLiP Trial): the feasibility of a cluster randomized crossover trial

BACKGROUND: Femoral shaft fractures are common severe injuries that carry an elevated risk of operative complications, including femoral malrotation, neurologic, and vascular injuries. There is no definitive research comparing two commonly used surgical tables and patient positions in aiding with both reduction and fixation of femoral shaft fractures. The objective of this pilot trial was to test the feasibility of a cluster randomized crossover trial that assesses the comparative effectiveness of supine positioning on a fracture table versus lateral positioning on a radiolucent table for antegrade intramedullary fixation of femoral shaft fractures. METHODS: Three orthopaedic trauma centres participated in this pilot trial. Each clinical site was randomized to a starting position, crossed over to the other treatment after 2 months, and alternated treatments in this fashion for the length of the trial. During the enrolment phase, we assessed compliance, enrolment rates, participant follow-up, and accurate documentation of the primary clinical outcome. The feasibility success criteria were: (1) 90% enrolment of eligible participants during enrolment phases; (2) 90% compliance with the trial interventions as per the cluster randomization crossover scheme; (3) timely collection of primary outcome data (i.e., within 6 weeks of fracture) in 95% of participants, (4) 90% completion of participant follow-up data; and (5) definition of the primary outcome as a categorical variable with an appropriate threshold value. Feasibility outcomes were summarized using descriptive statistics reported as means (standard deviation) or medians (first quartile, third quartile) for continuous variables depending on their distribution and counts (percentage) for categorical variables. RESULTS: All five of the criteria for feasibility were met. Of the 110 eligible patients identified at the three clinical sites, 101 (91.8%) were enroled over a 2.5-year period and 95/101 (94.1%) received the correct cluster-assigned treatment. The primary outcome (malrotation measured on the CT) was accurately documented within 6 weeks of fracture for 98% of participants (99/101) with 93 participants completing the final follow-up (92.0%). Lastly, the trial data informed an appropriate threshold, a malrotation cut off of 15°, for the primary outcome in the definitive trial. CONCLUSIONS: These results confirm the feasibility of a definitive trial comparing patient positioning during intramedullary fixation of femoral shaft fractures using a cluster randomized crossover trial design. However, due to funding limitations, a slower than anticipated enrolment, and concerns with surgical equipoise, this trial did not proceed to the definitive phase. TRIAL REGISTRATION: ClincialTrials.gov NCT03868280.