Endosteal strut using a hydroxyapatite/poly-L-lactide mesh tube with a proximal humeral locking plate for the treatment of proximal humeral fractures

Purpose: Proximal humeral fractures cause large intramedullary bone defects after humeral-head reduction. Hydroxyapatite/poly-L-lactide (HA/PLLA) materials are widely used for various fractures. However, the efficacy of endosteal strut using a HA/PLLA mesh tube (ES-HA/PLLA) with a locking plate for treating proximal humeral fractures was not reported. The purpose of this study is to examine the efficacy of ES-HA/PLLA with a proximal humeral locking plate in proximal humeral fractures.

Methods: Seventeen patients with proximal humeral fractures treated using ES-HA/PLLA with a locking plate from November 2017 to November 2021 were evaluated. The range of motion of the shoulder and postoperative complications were assessed at the final follow-up. Radiographs were evaluated to assess bone union and loss of reduction by measuring humeral-head height (HHH) and humeral neck-shaft angle (NSA).

Results: The average flexion and external rotation of the shoulder at the final follow-up were 137° (range, 90-180°) and 39° (range, - 10 to 60°), respectively. All fractures were united. The average HHH and NSA just after the surgery and final follow-up were 12.5 mm and 11.6 mm and 129.9° and 127.4°, respectively. Two patients presented screw perforation of the humeral head. One patient underwent implant removal due to infection. Avascular necrosis of the humeral head was observed in one patient with arthritis mutilans.

Conclusions: The use of ES-HA/PLLA with a proximal humeral locking plate resulted in bone union in all patients and prevented postoperative loss of reduction. ES-HA/PLLA is one of the treatment options for proximal humeral fractures.