Background: Fractures of the humeral head are a relevant problem in orthopedic surgery and the optimal therapeutic strategy of displaced fractures remains debated controversially in literature. In this respect, a special locking-plate was designed recently for the humerus to improve fixation of open reduction. However, analysis of larger series are still missing. Hence, the aim of this study was to analyze prospectively all patients suffering from humeral head fractures which were stabilized by the internal fixation system PHILOS (Synthes).
Patients and Methods: From 01/2002 until 08/2005 225 displaced humeral head fractures were treated by PHILOS plates. The fractures were classified according to the classification of Neer. Mean observation period was 9 months postoperative. For clinical evaluation the constant score was calculated after a mean observation period of 9 months. Moreover, an X-ray was performed in two plains to judge the implant position. From the total collective of 225 patients, an amount of 176 patients were enclosed into the clinical evaluation. The others were either deceased, or could not be contacted for other reasons.
Results: Out of the enrolled 176 patients into the follow-up study, 35% were Neer III, 43% were Neer type IV/V-3, and Neer type IV/V-4 were found in 12% beside 10% others. After 9 months, the mean constant score was absolute 75 ± 17 points. In direct postoperative X-ray of the 225 patients, a correct reduction and adequate axis between head and shaft was found in 92% of the patients. However, in 14% incorrect implant position was present in terms of intraarticular screws (11%) and elevated plate position in 6 cases. Moreover, after 9 months 8 patients demonstrated secondary implant dislocation, 3 of the head and 5 of the shaft and 14% suffered from secondary screw perforation into the joint due to humeral head sintering. Complete necrosis of the humeral head was present in 5 cases whereas partial necrosis was proven in 9 patients. Since sometimes, several complications were present in a single patient, the total amount of complication cases was 29 and these patients required secondary surgery.
Conclusion: The PHILOS locking plate system allows for an reliable internal fixation of humeral head fractures presenting a reasonable low complication rate. However, surgical pearls comprise mandatory cerclages of both tubercula framed onto the plate and correct axis of humeral head reposition. Typical pitfalls are intraarticular screws, secondary sintering and mislead anticipation of the stronghold of screw fixation in the bone by the locking mechanism. An randomized prospective study is currently on the way to further illuminate the quality of locking plate systems in the humeral head.
