Conformity of Proximal Humerus Internal Locking Plate System (PHILOS) and Anatomic Features of Proximal Locking Screws: Cadaveric Study / 대한정형외과학회잡지

ABSTRACT

PURPOSE: The purpose of this cadaveric study was to evaluate the conformity of the anatomically preshaped proximal humerus internal locking plate system (PHILOS) to the humeri of the Korean and anatomical features of nine locking screws for the proximal humerus. MATERIALS AND METHODS: This study included 20 adult humeri (average length 30.2 mm) with no deformity or previous surgery. PHILOS was applied to the lateral surface of the proximal humerus according to the contour. Then, the distance from the outer surface of the plate to the greater tuberosity and bicipital groove was measured. After K-wires were passed through the proximal locking guide, the intra-osseous length of K-wire and the configuration of the K-wire exit were evaluated. RESULTS: The overall conformity of PHILOS was excellent at the lateral aspect of the proximal humerus. The tip of the plate had an average distance of 3.6 mm (range, 1.4-6.6 mm; standard deviation [SD], 1.27) from the greater tuberosity and 2.5 mm (range, 0.0-4.6 mm; SD, 1.24) at the bicipital groove and the average intra-osseous length of K-wire through the locking guide was 41.1 mm (range, 23.5-53.7 mm). K-wires were evenly penetrated through the humeral head. On H8 and H9, the bottom hole of PHILOS is closely located at the most inferior area of the humeral articular surface. The bicipital groove was pierced by K-wires of H5, which was the middle hole of PHILOS in four cases (20%). CONCLUSION: PHILOS had excellent conformity with the proximal humerus and K-wires through the locking guide were evenly penetrated through the humeral head. However, much care should be taken in piercing of the bicipital groove in H5.