Our department used the proximal humerus internal fixation system to treat 32 cases of complex proximal humerus fractures, and achieved relatively satisfactory results. Clinical data There were 32 patients in this group, and the average time from injury to surgery was 2.6 days (1~12 days). The fracture was repositioned under direct vision, and the bone plate was placed 5-8 mm distal to the tip of the greater tuberosity of the humerus and lateral to the inter tuberosity groove, and screw fixation was performed. Postoperative management Active functional exercise of the hand and wrist was performed on the first postoperative day, and the passive oscillation of the shoulder joint was moderately increased on the second day, and the passive activity was moderately increased on the third day. Follow-up Outpatient follow-up was performed at 4, 6, 12 weeks and 6 months after surgery and every 6 months thereafter. The shoulder function was rated according to Constant-Murley criteria, with 86-100 being excellent, 71-85 being good, 56-70 being fair, and 0-55 being poor. Results All 32 patients in this group were followed up with a mean follow-up time of 16.2 months (10-22 months). The fractures healed completely in 12.1 weeks (10-16 weeks) on average after surgery, with no deformity healing. There was no internal fixation breakage or loosening, no screw penetration or cutting, and no complications such as rotator cuff impingement. No ischemic necrosis of the humeral head was found in this group of patients. Discussion Most proximal humeral fractures are comminuted Neer type 3 or 4 fractures, and it is difficult for a typical internal fixation to provide the stability required for early functional exercise. Locking plates for angular stability are designed to resist the pullout force of osteoporotic fractures and are stronger than normal plates. The fracture is repositioned as anatomically as possible to reduce soft tissue stripping and restore medial cortical support. The most important reason is the lack of medial cortical support, which causes excessive local stress and inversion. Inversion can also cause screws to cut out of the humeral head, plate screws to pull out or break, which become the most common reason for revision. The screw should not penetrate the humeral head into the glenohumeral joint. Many studies have shown that for complex proximal humeral fractures, shoulder scores are higher with incisional reduction and locking splint fixation than with hemi-shoulder replacement. We believe that there is insufficient clinical evidence that arthrodesis is superior to locking plates, and that arthrodesis is associated with complications such as pain, shortening of the rostro-humeral distance, osteolysis and bone resorption at the tuberosity site, so arthrodesis should be chosen with caution in phase I.