17 patients have undergone 20 microdrilling procedures to stimulate bone union in cases of established non-union. This occurred at the docking site following completion of bone transport using a stacked Taylor Spatial Frame, non-union following arthrodesis or non-union in long bone fracture.

Additional bone grafting was performed in only one patient. Further stimulation of union via injection of Bone Morphogenetic Protein was undertaken with 3 microdrilling procedures.

Of the 20 microdrilling procedures, 8 were considered fully successful in terms of stimulation of union, 7 were partially successful and 5 were not felt to have been successful.

The mean time to fully successful union following microdrilling was 11.4 weeks, ranging from 6 to 19 weeks.

There were 2 complications, both acute infections at the microdrilling site. Both of these were in patients with previous significant pin site infections.

We present the use of a microdrilling technique as a safe and effective minimally invasive technique that promotes union in cases of refractory non-union, whilst avoiding the donor site morbidity associated with open bone grafting.

We present, as a pilot study, our experience in the use of this technique in patients treated with circular frames for acute fractures, at the docking site in cases of bone transport and in cases of non-union following arthrodesis.