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.

Objective: to study the clinical performance of a new intramedullary nail, which is introduced in a retrograde way, for the treatment of humeral shaft fractures.

Design: prospective, non-randomized multicentrical clinical study.

Setting: Level I trauma centers in 4 European countries.

Patients: In a two year period, 102 humeral shaft fractures in 102 patients were nailed. Seventy-three fresh fractures, 12 pseudarthroses, 3 refractures and 14 pathological fractures were involved. Decision for nailing was taken by each surgeon individually. The diaphysis was defined as the part of the humerus between two centimetres below the surgical neck and five centimetres above the olecranon fossa. Sixty-six fractures were closed: 62 grade I and 4 closed grade II and III. There were also 7 open fractures, 4 grade I, 2 grade II and one grade III.

Intervention: all fractures were stabilized with the new unreamed humeral nail (UHN), which was introduced in a retrograde way.

Main outcome measurements: 42,5% of operations were performed in less than one hour, 82,4% in less than 90 minutes (skin to skin). In four patients (3,9%), additional fissures or fractures occurred on the entry portal, in one patient (1%) an additional diaphyseal fracture occurred during nail insertion. There were 4 (3,9%) secondary radial nerve palsies. Seventy-five fractures could be followed up until fracture healing, 58 fresh fractures, 9 pseudarthroses, 2 refractures and 6 pathological fractures. Five fractures needed more than 8 months for fracture healing, in all these patients (5/75 = 6,7%) secondary surgery was necessary. In three patients, inter-fragmentary compression was used with the UHN, once cancellous bone grafting was performed and in one patient changement of procedure to plate and screw osteosynthesis was considered necessary. Sixty-seven patients (89,4%) showed an excellent shoulder function and 7 (9,3%) an acceptable one, 66 (88,0%) an excellent elbow function and 7 (9,3%) an acceptable one at the time of fracture healing.

Conclusions: The unreamed humeral nail (UHN) is a very elegant device for intramedullary stabilization of fresh and pathological fractures and pseudarthroses. The retrograde approach is safe when the nail is introduced carefully through an appropriate entry portal. In case of good fragment adaptation and sufficient stability, an unproblematic fracture healing can be expected.