A Randomized Controlled Trial Comparing a 3D-Printed Endosteal Anatomical Support (EAS) System Versus the Standard PHILOS Plate for the Treatment of Severely Displaced Proximal Humeral Fractures

Background: Restoration of the medial calcar is crucial for stable fixation of severely displaced proximal humeral fractures. A novel 3D‑printed endosteal anatomical support (EAS) system has been developed for minimally invasive medial reconstruction. Preliminary clinical experience suggests favorable outcomes, including excellent functional recovery and low complication rates. This study aims to evaluate the superiority of the EAS system versus standard angular stable plate (PHILOS) in the treatment of severely displaced proximal humeral fractures through a prospective randomized controlled trial.
Methods: This is a randomized, semi‑blinded, multicenter controlled trial designed in accordance with the CONSORT statement for proximal humeral fractures. The study will compare the novel 3D‑printed EAS system with PHILOS plate fixation in terms of functional outcomes after open reduction internal fixation (ORIF) for severely displaced three‑ and four‑part proximal humeral fractures, with follow‑up at two and five years. Participants aged 45–90 years with AO‑OTA type 11‑B1, C1 or C3.1 fractures will be recruited from two hospitals. A total of 98 patients will be randomized to each group via an Electronic Data Capture (EDC) system. The primary outcome is shoulder function assessed by the Constant score at 12-month post-operatively. Secondary outcomes include the DASH shoulder score, radiographic scores and related complications. Follow‑up assessments are scheduled at 3, 6, 12, 24 months, and five years. The trial is semi‑blinded, with physiotherapist blinded to treatment allocation during functional evaluations.
Discussion: To our knowledge, the 3D‑printed EAS system is the first 3D‑printed implant designed for severely displaced proximal humeral fractures. This large‑scale semi‑blinded trial directly compares two surgical strategies and may provide important evidence to guide clinical decision‑making. The 3d-printed EAS system offers a minimally invasive approach with enhanced initial stability and potentially superior mid‑term functional outcomes, representing a promising alternative for managing these complex fractures.
Trial registration: Chinese Clinical Trial Registry (ChiCTR): 2000038167.
Keywords: Proximal humeral fracture, Surgical treatment, Randomized clinical trial, ORIF, Endosteal anatomical support, Philos plate, Physical therapy, Semi‑blinded