Efficacy of 3D printing assisted anterolateral acromial approach in the treatment of Neer type 3, 4 of proximal humeral fractures

Objective To observe the clinical effect of 3D printing assisted anterolateral acromion approach in treatment of Neer type 3 and 4 of proximal humerus fractures (PHF).

Methods  A total of 43 patients with Neer type 3 and 4 of PHF who underwent anterolateral acromial approach were selected and randomly divided into control group (n=20) and 3D printing group (n=23). Operation time, intraoperative blood loss, fluoroscopy times, anatomic reduction rate and postoperative drainage volume were compared between the two groups. Follow-up for 12 months, the shoulder Neer score and Constant-Murley score (CMS) were recorded and compared between the two groups.

Results  The operative time, intraoperative blood loss, postoperative drainage volume and C-arm fluoroscopy times in the 3D printing group were significantly shorter or less than those in the control group (P < 0.05). Fracture healing time and 12 months postoperative pain score in the 3D printing group were significantly shorter or lower than those in the control group (P < 0.05). Neer scores of 3 and 12 months after surgery and muscle strength, daily activity and joint range of motion score 12 months after surgery in the 3D printing group were significantly higher than those of the control group (P < 0.05). Three months after surgery, the humeral head loss height and the humeral head varus angle in the 3D printing group were significantly lower, while the humeral neck trunk angle was significantly higher than that in the control group (P < 0.05). There was 1 case (4.35%) of humeral head necrosis in the 3D printing group, and 3 cases (15.00%) in the control group, and the fractures of the rest patients were all healed.

Conclusion  The application of 3D printing technology to assist the anterolateral acromial approach in treatment of Neer type 3 and 4 of PHF can significantly shorten the operation time and fracture healing time, reduce intraoperative blood loss, and reduce the damage to the proximal humerus blood supply, and significantly improve the shoulder joint function of patients.