Femoral lengthening in children and adolescents.

Current lengthening techniques are still based on the Ilizarov method and the concept of callotasis. Research and progress in medical devices have led to constant improvement in results. Hexapod fixators allow more precise correction of complex deformities, with shorter learning curve. Associating lengthening by external fixation (EF) to internal fixation (K-wire, intramedullary nail or locking plate) has reduced EF times and complications rates, while improving anatomic and functional results. Lengthening nails provides faster recovery of range of motion and return to activity during lengthening and consolidation, with better psychological tolerance. Lengthening with deformity correction by retrograde nailing has no impact on consolidation. Monolateral EF is a reliable and easy-to-implement technique that is well tolerated by patients. Association to internal fixation gives promising results. Bone healing solidity assessment on plain X-ray is highly subjective, with wide inter- and intra-observer variation; bone mineralization is better assessed in terms of pixel-value ratio (PVR: ratio of pixel value of regenerate to adjacent bone) on picture archiving and communication system (PACS) digitized radiographs, providing objective assessment of callus solidity.