A matched comparison of suprapatellar and infrapatellar approaches in intramedullary nailing for distal tibial fractures: a study of alignment including rotation and mid-term outcomes

Purpose: This study compared the suprapatellar (SP) and infrapatellar (IP) approaches for intramedullary nailing (IMN) of distal tibial fractures, emphasizing alignment and mid-term functional outcomes. Distal tibial fractures pose alignment challenges owing to their wide metaphyseal region and risk of malalignment. Unlike previous studies, we used computed tomography (CT) to assess rotational alignment with a mean follow-up of 2.5 years to evaluate mid-term outcomes. Methods: We performed a retrospective matched analysis of 56 patients treated for SP or IP IMN between January 2010 and November 2022, who were matched for age, sex, and fracture characteristics. Radiological assessments included coronal, sagittal, and rotational alignments evaluated using CT. Functional outcomes were measured using the Lysholm Knee Score. Statistical analyses were conducted to compare union rates, malalignment, and complications, with significance set at p < 0.05. Results: Bone union was achieved in all SP cases (100%) and 96.4% of IP cases (p = 0.362). Coronal malalignment occurred in 7.1% of the SP and 25% of the IP cases (p = 0.024). Sagittal malalignment was absent in SP cases but present in 39.3% of IP cases (p < 0.001). Rotational malalignment was noted in 7.1% and 21.4% of SP and IP cases, respectively (p = 0.131). The Lysholm scores were similar between groups (p = 0.215). Conclusion: Both approaches yielded high union rates and comparable functional outcomes. However, the SP approach demonstrated superior coronal and sagittal alignment, which reduced the risk of misalignment. These findings highlight the importance of CT in assessing rotational alignment and support the SP approach for improving fracture alignment without compromising function.