Proximal humeral fractures account for approximately 6% of all fractures and are one of the most common fracture types in elderly patients, with about 20% requiring surgical treatment. Locking plates offer advantages such as anatomical-morphology matching, built-in suture holes, and angular stability. In recent years, they have been widely used in the internal fixation treatment of proximal humeral fractures and have achieved good clinical efficacy. However, for proximal humeral fractures with comminuted medial calcar, since the Philos locking plate placed on the lateral side cannot directly perform anatomical reduction on the comminuted medial calcar to provide sufficient support, postoperative complications such as varus deformity, internal fixation failure, and non-union are often prone to occur. In light of this, various methods have been adopted in clinical practice to support and stabilize humeral fractures. The Philos locking plate, placed on the lateral side of the humerus, with its spacing screws, can directly support the crushed medial column of the humerus. However, for petite patients (such as short women), its applicability is often limited. Fibula bone graft support can provide biomechanical strength and shows good mechanical stability. However, once conditions such as humeral head necrosis or obvious greater tuberosity absorption occur, surgical revision becomes significantly more difficult. The double-plate fixation treatment technology of outer PHILOS locking plates combined with auxiliary micro-plates has been widely applied recently. It significantly enhances stability and has a clear therapeutic effect. In addition, as one of the commonly used fixation methods for proximal humeral fractures, intramedullary nail fixation can preserve the blood supply to the humeral head through minimally invasive surgical procedures. Its load-dispersion design and the way the humeral center is fixed give it significant biomechanical advantages in stabilizing medial-compression fractures of the proximal humerus. Although double-plate fixation and intramedullary nail fixation are currently used for proximal humeral fractures with medial calcar comminution, direct comparative evidence remains limited.

To evaluate and compare the imaging and clinical effects of double plate and intramedullary nail fixation in the treatment of comminuted proximal humeral fractures with medial calcar of the humerus.

A retrospective analysis was conducted on 46 patients with proximal humeral fractures accompanied by fragmentation of the medial humeral calcar who underwent surgical treatment at the trauma center of our hospital from January 2017 to July 2024. Patients underwent double-plate fixation (n = 24) or intramedullary nails fixation (n = 22). According to the Neer classification, there were 16 cases of two-part fractures and 30 cases of three-part fractures. The causes of injury were as follows: 21 cases of traffic injuries, 17 cases of falls, and 8 cases of falls from heights. During outpatient follow-up at 1, 3, 6, and 12 months after the operation, shoulder joint X-ray imaging and clinical efficacy evaluation were performed for the above patients, and postoperative complications were also evaluated at the same time. Functional assessment indicators include: Shoulder joint range of motion (ROM), the American shoulder and elbow surgeons (ASES) score, and the Constant-Murley score to evaluate shoulder joint function.

Except for one patient whose fracture healed 5 months after the operation, the fractures of the remaining patients all healed 3 months after the operation. In the double-plate group, 2 cases had screw penetration and underwent revision surgery. One patient in each group experienced proximal screw loosening, but no reoperation was required. Ischemic necrosis of the humeral head was not found in either group. In imaging examinations of the two groups of patients before the operation and 12 months after, there was no significant difference in the neck-shaft angle. The shoulder joint range of motion, average ASES score, and Constant-Murley score in the double plate group were all better than those in the locked intramedullary nail group. Still, there was no statistically significant difference at the 12-month follow-up after the operation.

Double plate and intramedullary nail fixation treatment with comminuted proximal humeral fractures of the medial calcar of the humerus can all achieve satisfactory therapeutic effects. There were no significant differences between the two in terms of joint ROM, ASES, and Constant-Murley scores. Intramedullary nail treatment carries the risk of iatrogenic rotator cuff injury, while patients with double plate fixation have better recovery of shoulder joint function after surgery.