Pedicled vascularized rib transfer for reconstruction of clavicle nonunions with bony defects: anatomical and biomechanical considerations.

Background: Clavicular nonunions with large bony defects, although rare, are difficult to treat and often result from multiple failed attempts at surgical management. Reconstruction using vascularized bone graft is the accepted standard in cases of large osseous defects.

Methods: An anatomical vascular corrosion study with cadaveric dissections and finite element analyses was designed to assess the feasibility of clavicular reconstruction with a musculo-osteous graft interposition based on a pedicled serratus anterior flap.

Results: Rib vascularization through the serratus anterior was demonstrated, so that the thoracic branch of the thoracodorsal artery can been considered a secondary blood supply for the seventh and eighth ribs. Single and double pedicled rib transfers allowed for reconstruction with as much as 8 cm of bone loss. The maximal stress found in the single-rib reconstruction interfaces was located at the medial contact of the plate with the clavicle. It was 2.7-fold higher than the maximal stress of the medial bow of the intact clavicle. Conversely, the double-rib reconstruction had improved mechanical resistance. A case report using a single-rib transfer supported the biomechanical study by showing that the maximal risk of material loosening was located at the medial bone interface.

Conclusions: Double vascularized rib transfer as part of a serratus anterior flap should be used instead of single-rib transfer to reconstruct large clavicle defects. This technique is reproducible and does not require microvascular anastomoses. Therefore, it has potential advantages over free fibula transfer.