Introduction: There is an increasing tendency for internal fixation of proximal metaphyseal fractures. Intra-medullary nailing only recently has been considered to be a valuable option in these cases. Through the development of new reliable implant types, nailing finds increasing acceptance.

Questions: Is intramedually nailing with a new angle stable titanium nail a safe procedure in the treatment of proximal humeral fractures and is it combined with a good outcome?

Material and methods: A prospective international mul-ticenter study with standardized study control focused on the “Proximal Humeral Nail (PHN–Synthes Inc.), possible complications and clinical outcome. 151 fractures had been treated in 11 hospitals, where 72 were A-type, 67 B-type and 12 C-type (AO). There were 37 male, 114 female patients, median age 66 years ranging from 16 to 97 years. The outcome had been measured through Constant-Morley scores and DASH scores. 108 patients could be followed up until 1 year postoperatively.

Results: Important complications were perforation of the articular surface by screw or spiral blade (n=8), pain due to the implant (n=10), dislocation of fragments (n=2), non union (n=2), humeral head necrosis (n=3) and wound infection (n=1). The Constant-Morley score shows in total mean values one year postoperatively 75.3 in the injured and 89.9 in the non-injured side. The DASH score pre-operatively was in total 5.9 and 9.3 one year postoperatively, where the best results could achieve 0 points, the worst 100 points.

Discussion: Analyzing the complications, perforation of the articular surface by screw or spiral blade and pain due to the implant or impingement at the nail base are clearly related the technical failure in performing nailing. Here or the nail has not been introduced profoundly enough or the length for the spiral blade was not determined exactly and probably not controlled intraoperatively. This is due to the individual accuracy of the surgeon. The development of non-union (2/108) shows a ratio equal or even better to what is reported in conservative treatment or plate osteosynthesis. Dislocation of fragments n the other side, show the limit of this procedure, where in multifragmentary fracture type one spiral blade will not be able to fix a fragments. Using additional hardware is possible, but might reduce the effect of an initially low invasive approach. Constant score and Dash-score results perform similar to plate osteosynthesis, where clearly C-type-fractures present the worst prognosis.

Conclusion: Proximal humeral nailing seems to be beneficial in A-type metaphyseal fractures. Even in many B-type fractures it is still a good alternative with limited incision to the plate osteosynthesis.

In C-type fractures it is not advisable as a standard routine, only for experienced surgeons it might be a possible solution in selected cases.