Extra-Articular Distal Tibia Fractures: A Mechanical Evaluation of 4 Different Treatment Methods

Abstract

This cadaveric biomechanical study compared the mechanical properties of standard plating (SP), locked plating (LP), intramedullary nailing (IMN), and angular stable intramedullary nailing (ASN) for the treatment of axially unstable distal tibia metaphyseal fractures (OTA type 43.A3) with an intact fibula. A distal tibia metaphyseal fracture was created in 30 fresh frozen cadaveric specimens by performing an osteotomy 30 mm above the plafond. The fibula was left intact. Specimens were divided into 4 groups. Specimens underwent fracture fixation with a standard distal tibia plate, a medial locked plate, an intramedullary nail, or an angular stable intramedullary nail. Specimens were loaded vertically along the tibial axis to 700 N, followed by cyclical loading at 700 N for 10,000 cycles, and then to failure. The IMN group demonstrated greater stiffness and load to failure than the LP group, which was greater than the SP group. The ASN group was not different in terms of stiffness and load to failure from the LP group for the number of specimens tested. The IM group required the greatest energy to failure, and all groups were significantly greater than the SP group. Under axial loading conditions with an intact fibula, both IMN and LP provide stable fixation. There was no advantage to the use of an ASN over a standard IMN. IMN resulted in the highest stiffness, load to failure, and failure energy for OTA type 43.A3 fractures with as little as 3 cm of distal bone stock.