Polyaxial locking plates in treating distal humeral fractures: a comparative randomized trial for clinical outcome.

Background: Management of distal humeral fractures remains to be one of the most challenging aspects in trauma surgery. Low profile plating systems with variable angle screw fixation represent a crucial advancement to the established angular stable locking plates with considerable attention in current research. The aim of the prospective randomized trial was to review the preliminary results and patients' outcome following treatment with these newly developed implants and to rule out potential differences in fracture treatment of two different plating systems.

Methods: Twenty patients with distal humeral fractures (AO 13-A1 - AO 13-C3) were included in the current study since 2014. After completing the randomization plan, patients were distributed into two groups for different variable angle locking plates (DePuy Synthes® VA-LCP vs. Medartis® Aptus Elbow). Functional elbow scoring (ROM, MEPS, QuickDASH) served as primary outcome parameter, while radiological fracture consolidation served as secondary outcome parameter. Follow-ups were conducted 6 weeks, 12 weeks, 6 months and 12 months after the operation.

Results: Seventeen of 20 patients (85%) concluded all follow-up examinations. Postoperative elbow extension deficiencies showed significant differences between the two groups in all follow-up examinations with a mean of Ø 18 +/- 7.4 degrees in the DePuy Synthes® VA-LCP group compared to a mean of Ø 6.5 +/- 7.5 degrees in the Medartis® Aptus Elbow group (p = 0.002) 12 months postoperatively. Functional scoring showed a disparate pattern. The Medartis® Aptus Elbow group achieved significantly better MEP scores during follow-up. However, the analysis of the QuickDash revealed better results of the DePuy Synthes® VA-LCP group in the first half and better results of the Medartis® Aptus Elbow group in the second half of the follow-up examination instead.

Conclusions: Considering the complexity of distal humeral fractures, the usage of anatomically preshaped low profile variable angle locking plates for operative treatment leads to good clinical results. Even though there might be some advances of the Medartis® Aptus Elbow plating system concerning postoperative ROM and elbow function, a consistent difference in the overall clinical outcome between the two plating systems could not be detected.

Trial Registration: https://clinicaltrials.gov/ct2/show/NCT03272490 Retrospectively Registered 1. September 2017.