Closed reduction and minimally invasive percutaneous fixation of proximal humerus fractures using the Humerusblock.

OBJECTIVE: To evaluate the results after closed reduction and percutaneous fixation of displaced fractures of the proximal humerus with the Humerusblock system.

DESIGN: Prospective case series.

SETTING: Level 1 trauma center.

PATIENTS AND METHODS: Fifty-eight consecutive patients with displaced proximal humerus fractures were followed over a mean period of 15.2 (12-28) months.

INTERVENTION: All patients were treated by closed reduction and percutaneous fixation using the Humerusblock.

MAIN OUTCOME MEASUREMENTS: Intra- and postoperative complications, secondary fracture displacement, rate of avascular necrosis, range of motion, pain according to a visual analogue scale, and the Constant-Murley shoulder score.

RESULTS: No intra-operative complications occurred. Implant removal was performed 6 to 8 weeks after the initial surgery. In 13 (22%) cases, secondary impaction of the humerus lead to perforation of k-wires through the articular surface requiring premature removal of the entire implant after an average time of 4.9 weeks. Five patients required revision surgery, including open reduction and fixation because of secondary fracture displacement. In five patients, k-wires loosened and backed out laterally, requiring revision surgery and retightening of the clamping screws in three cases and premature implant removal in two. Two patients showed radiologic signs of partial avascular necrosis at the final follow-up. The average range of motion of the operated shoulder was flexion 119.2 degrees, extension 33.5 degrees, internal rotation 64.2 degrees, external rotation 41.4 degrees. and abduction 107 degrees. The mean visual analogue scale pain score was 1.1 points, and the mean Constant-Murley score was 73.6 points, representing 88% of the mean Constant-Murley score of the unaffected shoulder.

CONCLUSION: The Humerusblock system allows reliable minimally invasive fixation of selected displaced proximal humerus fractures, even in elderly patients with potentially reduced bone mass. In this study, postoperative rates of avascular necrosis were lower than that which has been reported after conservative treatment and open anatomic reduction and internal fixation. The overall unplanned re-operation rate of 40% was high, comparable with what has been reported for conventional percutaneous pinning. However, clinical outcome was good in 77% of the patients, and reduction could be held in 91% successfully, including elderly patients with potentially reduced bone mass.