The effect of medial calcar support on proximal humeral fractures treated with locking plates

Background Studies have reported mixed results on the importance of medial calcar support for the treatment of proximal humeral fractures. The purpose of this study was to compare radiographic and functional outcomes of patients who had displaced proximal humeral fractures with varying levels of medial support. Methods We performed a retrospective comparative cohort study. The study was conducted at a Level III trauma center in Taiwan. Seventy patients with proximal humeral fractures were collected retrospectively from 2015 to 2019. Only patients with two-, three-, or four-part types (Neer type I, II, or III) of displaced proximal humeral fractures were included in this study. However, patients with head-split fracture patterns, shoulder dislocation, prior shoulder trauma, and poor fracture reduction present in postoperative films were excluded. We assessed the radiographic outcomes, including the reduction score and amount of impaction in the humeral head. The functional outcome was evaluated based on the Constant score. Results Patients were grouped into the intact medial calcar group and the medial calcar deficiency group. In a subgroup analysis, the group with intact medial support had a significantly lower amount of impaction and a higher Constant score compared with the medial calcar deficiency group. Additionally, the groups with intact medial support had a nonsignificant difference in the Constant score between the affected side and the contralateral side. Conclusion The amount of impaction and the reduction score in the humeral head at the 12-month radiographic follow-up were significantly higher in the group with medial support deficiency. However, the reduction score after surgery exhibited no difference. This implies that the inherent nature of medial comminution of proximal humeral fracture may lead to inferior radiographic outcomes.