The effect of medial support screw in locking plate fixation of proximal humeral fractures

Abstract

Objective To evaluate the influence of medial support screw in locking plate fixation of proximal humeral fractures. Methods From June 2006 to November 2009, 68 cases of proximal humeral fractures were treated with locking plate fixation. The patients were divided into two groups, - MSS group and + MSS group. 39 patients were assigned to - MSS group and treated only with locking plates. 29 patients were assigned to + MSS group and treated with a medial support screw in addition to the locking plate. Statistical methods were applied to assess postoperative radiological parameters and shoulder function of both groups.Results The mean follow-up period was 7.4 months (range, 3 to 12 months). All fractures united at an average of 5.6 months. Fixation failure was observed in 1 case of the + MSS group and in 9 cases of the - MSS group,which were all found within 12 weeks postoperatively. The incidence of fixation failure was significantly different between the two groups( P = 0.036), so was the greater loss of neck-shaft angle observed in - MSS group ( P = 0.049). No difference was found between the two groups on the incidence of varus displacement of the humeral head(P=0.216). According to Constant Shoulder Score, the excellent and good rate was 79% and 62% in + MSS group and -MSS group, respectively. The difference in Constant Shoulder Score was statistically significant. Conclusion Locking plate fixation has been shown to lead to satisfactory outcomes for the treatment of proximal humeral fractures. An additional medial support screw, which can be inserted into the medial inferior region of the humeral head, is suggested to maintain reduction of the fracture and to improve stability of the fixation. Key words: Humeral fractures,proximal; Internal fixators; Treatment outcome; Locking plate