Objective To assess the effectiveness of a novel minimally invasive Achilles tendon suture instrument in the treatment of fresh closed Achilles tendon rupture. Methods A retrospective study was conducted on 150 patients who underwent surgical intervention for fresh closed Achilles tendon rupture. Eighty patients were treated with the novel minimally invasive Achilles tendon suture instrument (minimally invasive group) and 70 patients with traditional open surgery (traditional group). The two groups were comparable in terms of gender, age, injured side, cause of injury, the interval between injury and operation, and the distance from the fracture end to the calcaneal tuberosity (P>0.05). The operation time, intraoperative blood loss, incision length, hospital stays, hospitalization expenses, and complications were recorded and compared. At 1 year after operation, the ankle joint function was evaluated by the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score. Results The minimally invasive group demonstrated significantly shorter operation time, smaller incision length, and lower intraoperative blood loss when compared with the traditional group (P<0.05). However, there was no significant difference in terms of hospital stays and hospitalization expenses between the two groups (P>0.05). All patients were followed up 12-24 months after operation (mean, 15.5 months). In the traditional group, 6 cases of incision necrosis and 7 cases of Achilles tendon adhesion occurred, while in the minimally invasive group, all incisions healed at first intention and no Achilles tendon adhesion occurred. The differences in the incidences of the two complications between the two groups were significant (P<0.05). At 1 year after operation, the AOFAS ankle-hindfoot score in the minimally invasive group was superior to that of the traditional group (P<0.05). Conclusion In comparison with traditional open surgery, the use of self-designed novel minimally invasive Achilles tendon suture instrument proves to be an ideal technique for treating fresh closed Achilles tendon ruptures. This approach offers the benefits of smaller incisions, fewer complications, and better postoperative functional recovery, without increasing hospital costs.