Serial changes in the head-shaft angle of proximal humeral fractures treated by placing locking plates: a retrospective study

BACKGROUND: Although the proximal humeral fractures (PHFs) treated with locking plate have been well applied, there are few studies concerning on the serial HSA changes after locking plate placement. The purpose of this retrospective study was to explored the clinical significance of serial HSA changes after surgery. METHODS: We retrospectively analyzed the clinical data of 122 patients between January 2012 to December 2016 in our hospital. The serial change of the HSA and Neer’s score of 122 patients were recorded and analyzed. Then, we evaluated the HSA changes affected functional recovery in conjunction with medial support (MS). Moreover, multivariable linear regression analysis was performed to identify any potential confounding factors that may influence functional recovery. RESULTS: Of 146 patients, 122 (50 males and 72 females) patients were finally enrolled in our study. Our preliminary data suggested that the most decrease of HSA occurred in the period of 1 to 3 months (p < 0.001) postoperatively, and functional recovery was significantly related with the change of HSA (R(2) = 0.647, p < 0.001). The presence of MS plays an important role in maintaining postoperative HSA and restoring function. Moreover, Neer type 4 fracture, the difference between the postoperative HSA (on the injured side) and that of the uninjured side (the ΔHSA), and the HSA change to the end of follow-up were all significantly associated with functional recovery. CONCLUSIONS: Serial HSA changes were evident in PHF patients in whom locking plates had been inserted; it is essential to maintain reduction for 1–3 months postoperatively. MS is important in this context and surgeons must maximally restore MS. Furthermore, the functional outcome tended to improve when the HSA of the injured side was restored to a value close to that of the uninjured side.