Abstract
Proximal humeral fractures are common injuries but there is no general agreement on the best method for fixing unstable and displaced 3 & 4 part fractures. A new implant – Proximal Humeral Internal Locking System (PHILOS) – has recently been introduced to fix these fractures. The aim of this study was to assess the effectiveness of the PHILOS plate in the surgical treatment of these fractures.
We operated upon 36 patients between March 2002 and December 2004. 33 of them were available for follow up, which ranged from 12–45 months. Assessment at follow up included radiological review, Constant and DASH scoring.
While recovery of movements and relief in pain was satisfactory, the strength of shoulder did not recover fully in any patient. There were two failures in our series, one due to breakage of plate. 4 patients have shown radiological signs of avascular necrosis of humeral head. The plate was removed in 4 patients due to impingement and / or mechanical block in abduction. Another 2 patients had to undergo arthroscopic subacromial decompression for the same reasons. We encountered the problem of cold welding and distortion of screw heads, while removing the PHILOS plate.
The broken plate was subjected to biomechanical and metallurgical analysis, which revealed that the plate is inherently weak at the site of failure.
The PHILOS plate does have inherent advantages over other implants for fixation of 3 and 4 part proximal humeral fractures but we are not convinced about its strength. Design of its proximal screws also appears less than satisfactory. The plate may cause impingement in some patients necessitating its removal later on, which itself may not be easy.
Correspondence should be addressed to Mr Bimal Singh, BOSA at the Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE
