Bone quality measured by the radiogrammetric parameter "cortical index" and reoperations after locking plate...

To analyse the radiogrammetric parameter "cortical index" (CI) and its predictive value for proximal humerus fractures. Furthermore, to investigate the reoperations and the cause of reoperations after locking plate osteosynthesis of displaced proximal humerus fractures.

113 consecutive patients (73 women and 40 men) with a median age of 66 years (range 18-100 years) were included in this study. The median follow-up time in our database was 4.7 years (range 45-72 months). For a comparative matched-group analysis of the CI, patients with a fall on the shoulder without fracture were selected. Demographic data and all reoperations were recorded after median 58 months postoperatively. The CI was measured at the proximal humeral diaphysis.

The CI showed to be significant lower in the fracture group (mean 0.28) when compared to the matched group (mean 0.47, p < 0.01). 39% patients underwent a reoperation within 40 months postoperatively. 24% were reoperated within the first 12 months postoperatively, and 15% were reoperated after 12 months or later. The reoperation was independent of bone quality (p = 0.85).

The risk for reoperation is independent of the CI even though the CI may be a predictor for proximal humerus fracture. Younger patients should be aware that surgical treatment of proximal humerus fractures might be a two-stage surgery. Regular follow-up visits for older patients during the first postoperative year must be assured.