The use of MR images to evaluate the risks associated with proximal locking of intramedullary tibial nails.

Vascular complications associated with locked intramedullary tibial nailing are infrequent but always serious, with a secondary amputation rate of 30%. These complications, based on an MR study of the anatomic relationships between the interlocking screws and the neurovascular or articular structures at the proximal end of the tibia, have been analysed. Two types of nails were used: one with anterior-posterior locking and a specially designed prototype with oblique locking. In particular this study emphasised the anatomic risk of injury to the popliteal structures when using anterior-posterior locking, as well as to the anterior tibial vessels and proximal tibiofibular joint when using oblique locking. As no locking method appears to be better than any other, the best is that associated with the lowest morbidity. Consequently, the use of frontal instead of anterior-posterior locking is recommended; the use of oblique locking, which this study has shown carries a much higher risk of complications, is strongly advised against.