Summary

Distance between GT and upper border of PHILOS and its correlation with clinical outcomes

Abstract

Background

While the utilizing greater tuberosity(GT) as a reference for PHILOS placement in proximal humerus fracture is commonly advocated. The explicit distance between GT and upper border of PHILOS and its correlation with clinical outcomes remains unclear.

Method

Patients diagnosed of displaced proximal humerus fracture underwent PHILOS fixation from January 2017 to May 2022 were included. Shoulders that did not meet the criteria for good reduction were excluded. Demographic and postoperative radiographic data were collected. Clinical outcomes, including range of motion (ROM) and functional outcomes, were evaluated at 1 year postoperatively. Patients were divided into two groups based on by GT to plate (GT-P) distance: group 1 (GT-P distance ≥ 5 mm) and group 2 (GT-P distance < 5 mm).

Results

Forty-six patients were included into study, with twenty-seven and nineteen patients categorized into group 1 and group 2, respectively. Height and weight of group 1 were significantly greater than group 2 (p-values were 0.013 and 0.19 respectively). Humeral head size in group 1 was also significantly larger than group 2 (diameter 50mm vs 45mm, p-value = 0.003). However, distance from calcar screw to calcar of humeral head was not significantly different between two groups. At 1 year post-operatively, group 1 experienced significantly greater range of motion in forward elevation (p-value = 0.001) and internal rotation (p-value = 0.047) than group 2, although functional outcomes including Constant and Murray score (CSS), American Shoulder and Elbow Shoulder (ASES) score and Shoulder Pain and Disability Index (SPADI) were not significantly different. Receiver operating characteristic (ROC) curve analysis identified a threshold of at least 4.8 mm for achieving forward elevation greater than 120°

Conclusions

GT to plate distance less than 5 mm may not significantly affect functional outcomes, except for forward elevation. An optimal greater tuberosity to plate distance of at least 4.8 mm is recommended for achieving forward elevation greater than 120°. Care should be taken in patients with hyposthenic bulid and small humeral head diameter, as this may result in a GT-P distance < 5 mm, impacting proper calcar distance.