Comparing the Biomechanical Stability of Cerclage Cable with Plate Insert Versus Locking Screw in Periprosthetic Humeral Fracture

Abstract

Background: In the setting of periprosthetic humeral fractures, the humeral stem of the implant represents a substantial challenge to the optimal method of proximal fixation. This study aimed to compare the initial biomechanical stability provided by cerclage cables with a locking plate insert versus bicortical locking screws (i.e., the gold standard for fixation) in fresh cadaveric humeri. Methods: After calculating the sample size, we utilized 10 sets of cadaveric specimens and created a 5-mm osteotomy gap 120 mm distal to the tip of the greater tuberosity, simulating a Wright and Cofield type-B periprosthetic humeral fracture on each specimen. Using 3 locking screws for distal fragment fixation, identical in all specimens, the specimens were assigned to Group A (3 cerclage cables with a plate insert) or Group B (3 locking bicortical screws) for proximal fragment fixation. Biomechanical tests included stiffness in varus and valgus bending, torsion, and axial compression, and a single load to failure. Results: No significant differences were observed in the biomechanical metrics between the 2 groups. Conclusions: Our study revealed that fixation with use of cerclage cables with a plate insert demonstrated biomechanical stability comparable with that of bicortical locking screw fixation when addressing the proximal fragment in Wright and Cofield type-B periprosthetic humeral fractures. Clinical Relevance: For proximal fragment fixation of periprosthetic humeral fractures, cerclage cables with a plate insert can be utilized as an effective fixation method that offers initial fixation strength that is comparable to the use of 3 locking bicortical screws.