Assessment of the efficacy of the far cortical locking technique in proximal humeral fractures: a comparison with the conventional bi-cortical locking technique

Locking plate fixation is one of the treatment strategies for the management of proximal humeral fractures. However, stiffness after locking plate fixation is a clinical concern. The mechanical stiffness of the standard locking plate system may suppress the interfragmentary motion necessary to promote secondary bone healing by callus formation. The far cortical locking (FCL) technique was developed to address this limitation in 2005. FCL increases construct flexibility and promotes callus formation. Our study aimed to evaluate the clinical and radiological outcomes of the FCL technique when implemented in proximal humeral fracture management. Furthermore, we compared the surgical outcomes of FCL with those of the conventional bicortical locking (BCL) screw fixation technique. Forty-five consecutive patients who had undergone locking fixation for proximal humeral fractures were included in this study. A proximal humeral locking plate (PHILOS) system with BCL screw fixation was used in the first 27 cases, and the periarticular proximal humeral locking plate with FCL screw fixation was used in the final 18 consecutive cases. Functional capacity was assessed using the constant score, American Shoulder and Elbow Surgeons (ASES) score, and range of motion. Radiographic outcomes were evaluated using the Paavolainen method of measuring the neck-shaft angle (NSA). No significant differences in clinical outcomes (ASES score, constant score, and range of motion) were found between the two groups. The union rate at 12 weeks was significantly higher in the FCL group (94.4%) than in the BCL group (66.7%, p = 0.006). No significant differences in NSA were found between the two treatment strategies. The complication rate was not significantly different between the two groups. When implemented in proximal humeral fractures, the FCL technique showed satisfactory clinical and radiological outcomes as compared with the conventional BCL technique. The bone union rate at 12 weeks after surgery was significantly higher in the FCL group than in the BCL group. However, no significant difference in the final bone union rate was found between the two groups.