The humeral shaft extends from the distal end of the surgical neck of the humerus to the proximal edge of the lateral epicondyle. Distal fractures are usually located at the distal one-third of the humerus. According to the national trauma database of the United States, distal humeral fractures account for 1.2% to 3.5% of all fractures in the body, with extra-articular fractures comprising 68%. Although conservative treatment can achieve a healing rate of 75%, surgical treatment can significantly shorten the recovery time and reduce the risk of malunion (OR=0.42, 95% CI: 0.28-0.63). At present, there is still controversy over the choice of surgical approach, with the focus lying in the balance between soft tissue protection and the risk of nerve injury. According to biomechanical research, when fixing humeral shaft fractures, it is usually necessary to implant four screws at each end of the fracture line (forming eight layers of cortical fixation). However, in distal humeral shaft fractures, we have almost no space to fix the distal end with conventional plates. Achieving firm fixation in distal humeral shaft fractures is more challenging. The posterior part of the humerus is flat, and the plate can be used without shaping and can be placed at the farthest end of the humerus to ensure the fixation strength and working length of the plate. Therefore, the posterior approach is a commonly used approach for treating distal humeral fractures. However, the posterior approach may carry the risk of damaging the radial nerve. The commonly used access routes at the rear can be divided into two types: one is the modified posterior approach to the distal humerus. Another one is the Triceps Splitting Approach to the Distal Humerus. Both approaches have distinct advantages and limitations.

To compare the clinical efficacy of the modified posterior approach and the triceps brachii splitting approach in the treatment of distal humeral fractures.

A retrospective analysis was conducted on 46 patients with distal humeral fractures admitted from December 2020 to December 2023. They were divided into the modified posterior approach group (24 cases) and the triceps brachii splitting group (22 cases) according to the surgical approach. The operation time, intraoperative blood loss, hospital stay, fracture healing time, elbow joint function (Mayo score), radial nerve injury, and incidence of incision complications were compared between the two groups.

Both groups of fractures healed, and there was no statistically significant difference in healing time (P>0.05). The amount of bleeding in the modified lateral group (100.27±23.39) mL was significantly less than that in the splitting group (209.38±25.78) mL, P=0.034, but the rate of radial nerve injury (8.33% vs 0%, P=0.036) was significantly higher. The incidence of incision complications in the splitting group (9.09%) was higher than that in the modified group (0%, P=0.041). One year after the operation, there was no statistically significant difference in the excellent and good rate of elbow joint function between the two groups (83.33% vs 77.27%, P=0.399) .

The modified posterior approach can reduce intraoperative bleeding, but the risk of radial nerve injury is relatively high. The triceps brachii splitting approach offers more comprehensive nerve protection, but it has a higher rate of incision complications.