Proximal humerus fractures account for 5% of all fractures, and the incidence is about 66/10,000 per year. More than 70% occurs in patients over 60 years, which is the second most common upper limb fracture in the elderly. As the aging population increases, and the accompanying risks of osteoporosis and falls, Palvanen, et al. predict that its incidence will double by 2030. Despite the current variety of treatments, anatomical locking plates and their modifications for proximal humerus have been developed to provide fracture fixation by using multiple locking screws implanted in different directions to maximize the number of screws, multi-angle support and resistance to displacement, which have achieved satisfactory clinical results. However, varus deformity, humeral head necrosis and screw cut-out are common complications. As a special type of four-part fracture, the treatment of impacted valgus proximal humeral fracture has certain particularity. The medial column is usually not comminuted, and the blood supply of medial periosteum is not obviously damaged. Therefore, the risk of varus deformity and humeral head necrosis can be significantly reduced, but the problem of screw cut-out cannot be avoided. Academics pointed out that the risk of proximal screw penetration in the glenohumeral joint is up to 43% for patients over the age of 60 with three-part or four-part proximal humeral fractures. This is associated with decreased bone mineral density and limited screw holding capacity in patients, thus affecting the biomechanical behavior of bone-internal fixation.

To investigate the effect of anatomical locking plate combined with injectable artificial bone graft in the treatment of impacted valgus four-part proximal humeral fractures in the elderly.

From July 2014 to May 2018, 11 cases of elderly patients with impacted valgus four-part proximal humeral fractures were treated with anatomical locking plate combined with injectable artificial bone graft, and the data was retrospectively analyzed. The study included 4 males and 7 females, and the mean age was 72 years. Postoperative pain, shoulder function and postoperative complications were assessed.

At the last follow-up, the mean VAS score was 1.6 points. Most patients had good shoulder function recovery. The average range of shoulder anteflexion was 166°, and the average range of . The average range of shoulder abduction was 166°. The average Constant-Murley score was 86.2 points; and the average Quick DASH score was 18.9 points. No cases of avascular necrosis of the humeral head, screwing or other internal fixation failure occurred during follow-up.

Injectable artificial bone graft on the one hand can fill the bone defect caused by valgus and compression. On the other hand, the enhanced force of the screw in the head can effectively solve the problem of proximal screw cut-out. Anatomical locking plate combined with injectable artificial bone graft is an effective option for treatment of impacted valgus four-part proximal humeral fractures in the elderly.