TresLock for Unstable Proximal Femoral Fractures: Morphological Compatibility and Clinical Results: A Case Series

INTRODUCTION: A new device, TresLock (KISCO DIR Co., Ltd., Kobe), has been used for the treatment of unstable proximal femoral fractures and was designed based on Japanese anatomical characteristics. It has three sliding hip screws with one side plate. The angle of all screws relative to the plate has been set to 128°, and each hip screw has a short thread (15 mm) to prevent crossing of the fracture line. In this study, we evaluated the morphological compatibility of TresLock. METHODS: We treated 10 patients with hip fractures using TresLock at our institution between September 2016 and December 2017. The average age of the patients was 83.8 years (range, 73–93 years). Fractures included five proximal neck transcervical shear fractures (Orthopaedic Trauma Association [OTA] type-31B2.3, Pauwels III) and five basicervical fractures (OTA type-31B3). The clinical course and three-dimensional computed tomography were evaluated postoperatively. RESULTS: In all cases, all three screws were inserted within the femoral neck. The screws were inserted at an axis of 2.5 ± 1.3° varus to the femoral neck axis. The distance from the subcapital line to the three (proximal-anterior, proximal-posterior, and distal) screw thread ends was 12.0 ± 1.8 mm, 10.4 ± 2.4 mm, and 11.6 ± 4.0 mm, respectively and was sufficient to actuate compression force. However, one case (Pauwels III) required reoperation because of non-union. CONCLUSION: Careful follow-up is needed, but TresLock shows good anatomical compatibility for femurs among the Japanese population.