Biomechanical evaluation of fixation techniques for isolated Letenneur Type I lateral Hoffa fractures: A cadaveric...

The aim of this study was to biomechanically evaluate and compare five different fixation techniques for isolated Letenneur Type I lateral Hoffa fractures using a fresh-frozen cadaveric model under both static and dynamic axial loading conditions.

Twenty-five fresh-frozen distal femurs were homogeneously assigned to five groups based on fixation method: (A) two postero-anterior (PA) screws (6.5 mm), (B) two antero-posterior (AP) screws (6.5 mm), (C) two PA screws combined with a posterior 3.5-mm tubular plate, (D) one PA screw combined with a lateral 3.5-mm locking compression plate (LCP), and (E) two AP screws combined with a lateral horizontal 3.5-mm tubular plate. Specimens underwent dynamic loading (2500 cycles, five stages, 2 Hz) followed by static axial loading using a servo-hydraulic testing machine. The parameters evaluated included load at 3-mm displacement, ultimate load, stiffness, and photogrammetric displacement.

Plate-augmented constructs demonstrated significantly superior biomechanical stability. Ultimate load was highest in Group C (1761.8 ± 299.5 N), followed by Group D (1564.4 ± 162.1 N) and Group E (1571.2 ± 420.8 N), all significantly greater than Groups A (902.4 ± 522.8 N) and B (1088.2 ± 323.1 N) (P < 0.01). Photogrammetric displacement was significantly lower in plate-augmented groups (Group C: 0.32 ± 0.24 mm; Group E: 0.59 ± 0.58 mm) (P < 0.05). No statistically significant differences were observed between screw-only constructs.

Plate-augmented fixation provides superior biomechanical stability for isolated Letenneur Type I lateral Hoffa fractures. Lateral plating achieves comparable stability to posterior plating while avoiding the technical challenges. The comparable performance of screw configurations suggests that screw trajectory can be flexibly selected based on fracture morphology. These findings offer guidance for surgical planning and implant selection in the management of these complex fractures.