140 – APPROACH-WITHDRAW TECHNIQUE OF INTRA-OPERATIVE FLUOROSCOPY TO AVOID INTRA-ARTICULAR SCREW PENETRATION WITH PROXIMAL HUMERUS LOCKING PLATES

Abstract

Purpose: Intra-articular screw penetration with the use of proximal humeral locking plates has a reported incidence in the literature of up 25%. It may occur early, due to an intra-operative unrecognized technical error, or as a result of late fracture collapse. This study was designed to demonstrate the “approach-withdraw” technique of intra-operative fluoroscopy which can be used to minimize the rate of early unrecognized intra-articular screw penetration.

Method: A radiographic review was undertaken of 37 patients with proximal humerus fractures fixed with either the PHILOS plate (Synthes, Westchester, Pennsylvania) or the Periloc proximal humerus plate (Smith and Nephew, Memphis, TN) by the senior author (JY) between 2002 and 2009. Intra-operative fluoroscopy was used in each case to ensure there was no intra-articular screw encroachment by visualizing each screw tip approach and then withdraw from the articular surface during live fluoroscopy as the shoulder was taken through a range of motion. Patients were then followed for an average of nine months with serial radiographs for post-operative intra-articular screw penetration, screw loosening, and maintenance of reduction. Maintenance of reduction was evaluated using the change in neck shaft angle and greater tuberosity to humeral height difference on the initial post-operative x-rays as compared to the x-rays at final follow-up.

Results: An average of six screws (range three to nine) was placed into the humeral head per patient. There was no incidence of intra-articular screw penetration on immediate post-operative radiographs. One patient had loss of reduction with a single screw breaching the sub-chondral bone and four screws loosening after a fall in the early postoperative period. The remainder of patients had no evidence of intra-articular screw penetration or screw loosening at last follow-up. One patient developed a non-union and had a subsequent reconstruction. The average change in neck shaft angle was four degrees (range 0° to 16°) and greater tuberosity to humeral head height difference was 1.9 mm (range 0 – 8.9).

Conclusion: The approach-withdraw technique is a useful intra-operative fluoroscopic test which may be utilized in the fixation of proximal humerus fractures to avoid unrecognized intra-operative screw penetration of the glenohumeral joint.