Introduction and Objectives: In 2000 Bösch published the results of a laterally displaced percutaneous sub-capital osteotomy of the first metatarsal, without medial exostosis resection and without soft tissue surgery. There is no data on the characteristics of the bone consolidation in relation to the level and displacement of the osteotomy. We present data on these variables.

Materials and Methods: This is a prospective clinical study of: 30 trans-epiphyseal osteotomies, 30 metaphyseal osteotomies, 30 diaphyseal osteotomies and 10 completely displaced and dislocated osteotomies of the first intermatatarsal space. There was a minimum 1 year clinical and radiological follow-up. All the osteotomies were fixated by means of a 2 mm diameter Kirschner nail.

Results: The epiphyseal osteotomies consolidated without any apparent periosteal callus, there was osteolysis and fragment impaction in 19 cases; 1 non-union and 3 delays in consolidation. The metaphyseal osteotomies consolidated with variable degrees of periosteal callus; in 9 cases there was osteolysis and fragment impaction, in 1 case there was non-union but this had consolidated spontaneously after 2 years. Diaphyseal osteotomies consolidated with abundant medullar-periosteal callus; in 5 cases there was fragment impaction. Diaphyseal osteotomies with head dislocation consolidates with abundant medullar-periosteal callus; in 7 cases there was metatarsal shortening (3mm–7mm).

Discussion and Conclusions: We found that 97% of the osteotomies healed perfectly in 2–3 months. The type of consolidation and whether there was or not metatarsal shortening depended on the bone tissue at the point of contact of the fragments: Cancellous-cancellous bone (epiphyseal osteotomies), cancellous-cancellous or cancellous-cortical bone (metaphyseal osteotomies, cortical-cortical bone (diaphyseal ostetomies).