The necessity of strength evaluation in assessment of clinical outcome after shoulder surgery : follow-up data from patients with complex proximal humerus fractures treated by locking plate fixation.

In order to minimize the bias of Constant score we modified the allocation of strength subscore. One hundred and two patients with 3- and 4-part proximal humerus fractures were treated using locking plate fixation and followed up for > 1 year. The clinical outcomes were assessed by DASH score abbreviated Constant score (AbbCS strength item excluded) modified Constant score (ModCS with 12-pound strength) and original Constant score (CS with 25-pound strength). The satisfaction rate was determined for each scoring instrument. Compared to CS the satisfaction rate was significantly higher in DASH score AbbCS and ModCS (all p < 0.001) but the latter 3 groups did not show significant difference. ROC analysis showed that a > 7-pound shoulder strength was present in patients with satisfied outcome assessed by DASH score. In conclusion strength evaluation is necessary for the assessment of shoulder function but the over-allocated strength should be modified in Constant score.