Minimally invasive plate osteosynthesis for humeral shaft fractures with the far cortical locking system: A matched comparison with the standard locked plating construct.

Abstract

The far cortical locking (FCL) system reduces axial stiffness in locked plating constructs while maintaining construct strength, thereby promoting secondary bone healing following fracture fixation. However, studies evaluating its efficacy compared with standard locked plating (LP) systems for upper extremity fractures remain limited. This study compared humeral shaft fractures treated with minimally invasive plate osteosynthesis (MIPO) using either the FCL or LP system. We analyzed 40 patients with diaphyseal humeral fractures treated with MIPO using either FCL or LP and conducted a matched-pair comparative analysis. Prospective data were collected from 20 consecutive patients who underwent MIPO with FCL. A matched case-control cohort was constructed by pairing MIPO cases using LP with the most closely matched FCL cases. The primary outcome was a comparison of radiographic and clinical fracture healing, as well as complications, between the two groups using statistical analysis. Statistical significance was set at p < 0.05. Union was achieved in 18 of 20 cases (90 %) in the FCL group at a mean of 13.6 weeks. All 20 cases in the LP group achieved union after a mean of 20.1 weeks. Time to union was significantly shorter in the FCL group (p < 0.05), though the union rate did not differ significantly (p = 0.49). Near cortex healing occurred at a mean of 11.2 weeks in the FCL group and 18.8 weeks in the LP group (p < 0.01). Two FCL cases required revision surgery due to screw breakage or pull-out at the proximal fracture segment. Mean coronal and sagittal angulations were 2.9° and 4.8° in the FCL group, and 2.4° and 3.3° in the LP group, with no significant differences (p = 0.60 and 0.24). No significant differences in functional outcomes were observed between the groups. The FCL group showed significantly faster union compared to the LP group, but no significant differences in union rate, alignment, or functional outcomes. Although not statistically significant, a 10 % complication rate was observed in the FCL group. Caution is warranted, as FCL screws may fail at the proximal fracture segment, either by breakage due to mechanical overload or by pull-out.