Objective To explore the effect of different approaches of intramedullary nail fixation on postoperative biomechanical stability and early weight-bearing in patients with tibial fractures. Methods A retrospective analysis was conducted on the medical records of 86 patients with tibial fractures admitted to the hospital from June 2018 to March 2024. The control group received intramedullary nail fixation through the infrapatellar approach, while the observation group received intramedullary nail fixation through the suprapatellar approach. Compare the intraoperative conditions, postoperative healing, knee joint stability and range of motion, hemorheology, and postoperative complications between two groups. Compare the recovery of knee joint function among patients in different weight-bearing groups, with early weight-bearing recorded within 4 weeks after surgery and late weight-bearing recorded 4 weeks after surgery. Results The observation group had fewer intraoperative fluoroscopy sessions than the control group (P<0.05). The normal healing rate of fractures in the observation group was higher than that in the control group (P<0.05). Three months after surgery, the Lysholm score, HSS score, and flexion range of motion in the observation group were higher than those in the control group (P<0.05). Six months after surgery, both groups showed an increase in Lysholm score, HSS score, and flexion range of motion (P<0.05), with the observation group having higher Lysholm score and HSS score than the control group (P<0.05). After surgery, plasma viscosity, hematocrit, and erythrocyte sedimentation rate decreased in both groups (P<0.05), with the observation group being lower than the control group (P<0.05). Among 86 patients with tibial fractures, 52 had early weight-bearing and 34 had late weight-bearing. At 3 and 6 months after surgery, the Lysholm score, HSS score, and flexion range of motion of early negative recombination were higher than those of late negative recombination (P<0.05). Conclusion The treatment of tibial fractures with intramedullary nail fixation through the anterior patellar approach can help promote the recovery of lower limb motor function in patients after surgery, and early postoperative weight-bearing can help promote the recovery of knee joint function.