Objective To compare the effectiveness of the infrapatellar approach versus the semi-extended parapatellar approach for intramedullary nailing in the treatment of type A tibial shaft fractures. MethodsA retrospective analysis was conducted on 66 patients with type A tibial shaft fractures treated with intramedullary nailing between May 2018 and February 2023. Among them, 23 patients underwent the infrapatellar approach (group A), 22 the semi-extended lateral parapatellar approach (group B), and 21 the semi-extended medial parapatellar approach (group C). There was no significant difference among the three groups in baseline data (P>0.05), including gender, age, cause of injury, time from injury to surgery, presence of concomitant fibular fractures, AO/Orthopaedic Trauma Association (AO/OTA) classification, and preoperative visual analogue scale (VAS) score for pain. The operation time, intraoperative blood loss, incision length, intraoperative fluoroscopy frequency, length of hospital stay, fracture healing time, knee range of motion (ROM) at 12 months postoperatively, Lysholm knee score at last follow-up, incidence of postoperative anterior knee pain, and incidence of postoperative skin numbness around the knee were recorded and compared. VAS scores were also evaluated preoperatively and at 4, 8, and 12 weeks postoperatively. Results All patients completed the surgery successfully, with primary incision healing in all cases and no incision infections. There was no significant difference among the three groups in intraoperative blood loss or length of hospital stay (P>0.05). The operation time was significantly shorter in group B compared to groups A and C (P<0.05), and incision length was significantly shorter in groups A and B compared to group C (P<0.05). The intraoperative fluoroscopy frequency, from least to most, was group B, group C, and group A, with significant differences (P<0.05). All patients were followed up 12-24 months, with no delayed union or nonunion. There was no significant difference among the three groups in fracture healing time (P>0.05). At 12 months postoperatively, knee ROM and incidence of postoperative skin numbness around the knee were comparable among groups (P>0.05). Groups B and C showed significantly lower incidence of postoperative anterior knee pain during follow-up and higher Lysholm scores at last follow-up than group A (P<0.05). VAS scores decreased gradually over time in all groups, with significant differences among all time points (P<0.05). At 4, 8, and 12 weeks postoperatively, VAS scores in groups B and C were significantly lower than those in group A (P<0.05). Conclusion Compared with the infrapatellar approach, the semi-extended parapatellar approach offers more accurate nail placement, easier fracture reduction, fewer intraoperative fluoroscopies, better late knee function, and fewer complications in the treatment of type A tibial shaft fractures. Among parapatellar approaches, the lateral approach demonstrates greater clinical advantages, with shorter operation time, fewer fluoroscopies, lower incidence of skin numbness around the knee, and suitability for patients with soft tissue contusions.