An innovative technique of rear entry creation for retrograde humeral nailing: how to avoid iatrogenic comminution

Antegrade and retrograde nails are widely used for intramedullary fixation of humeral shaft fractures. Creating the rear entry is the crucial step for retrograde nailing. The common manual technique is associated with considerable risks of additional iatrogenic comminution of the distal humerus.

A specific device for the creation of a rear entry hole has been developed as part of the instruments for humeral shaft nailing (Targon H) and made commercially available (BBraun Aesculap, Germany). After standard triceps-splitting approach, a guide instrument is firmly applied to the distal humerus with one screw. The screw hole is later used for distal interlocking. The oval rear entry hole is then performed by frontal cutter along the guide.

We have been performing a retrospective evaluation of all unreamed humeral nailings (Targon H) since 2000. Operation time, use of the guide instrument and intra-operative problems were analysed. X-rays were checked for iatrogenic humeral comminution directly after the operation and after physiotherapy. Cases of infection and nonunion were noted.

We identified 87 cases of intramedullary fracture fixation with an interlocking nail (46 antegrade, 41 retrograde). In all retrograde cases a guide instrument and an access reamer were used for the creation of an entry hole. No iatrogenic comminutions were observed during the operation or on postoperative X-rays. Active postoperative exercises were generally allowed in every patient. Mean operative time was shorter for retrograde than for antegrade nailing (90 min vs. 108 min; p = 0.012). We saw two nonunions (2%) and no infections.

Use of access reamer and guide instrument is a safe and reproducible way of creating a rear entry hole for retrograde humeral nailing. The risk of additional comminution seems to be eliminated.