All current methods of gradual leg lengthening rely on distraction osteogenesis. The basic principles of bone generation and moulding-gentle, periosteum-respecting osteotomy followed by incremental 1-mm/day fragment separation and consolidation-are set. The patient and his psychosocial, medico-economic, logistic and legal environment must be consented, educated and prepared for a potentially long-lasting journey paved with hazards such as delayed consolidation, pseudarthrosis, malalignment, joint contractures and dislocations, pain, infection, prolonged inability to work and refrain from school and sports activities. Nevertheless, there are still considerable biological limitations and challenges. Recent developments in deformity correction allow for a patient- and surgeon-friendly web-based bone restoration of any complex three-dimensional deformity. Hence, acquired or congenital disparities ought to be restored, though the apodictic and historic 2-cm rule of acceptable leg length discrepancy is more enigma than science in light of the individual anatomic parameters such as pelvic width, absolute leg length, muscle force and proprioceptive capacity. Leg length inequality is a correctable risk factor for knee osteoarthritis. ĭespite a lack of biomechanical data supporting a seemingly fundamental human anatomic principle, it is persistent orthopaedic common sense that the pelvis needs to be horizontal and the lumbar spine symmetrically loaded in a bipedal standing position and in the stance phase during gait. Leg length discrepancies are frequent: about one-third of the population shows 0.5–1.5-cm disparities, 5 % more than 1.5 cm and about 1/1,000 have been prescribed a shoe lift. In any case, wise judgement of the patient’s deformity, medical and biological situation, psychosocial environment, selection of the appropriate method and hardware, as well as meticulous operating technique by an experienced surgeon are the cornerstones of successful outcomes. Overall, limb lengthening, particularly in combination with multi-planar deformity correction, can still be an arduous endeavour. It remains to be proved if the significantly higher implant costs are compensated by lower treatment costs.
Hence, they offer a valuable alternative for low-grade complexity situations. Mechanical or motorised, minimally invasively placed nails prevent muscle fixation and, therefore, ease rehabilitation, increase patient comfort and potentially shorten the overall time of sick leave and refrain from sports activities. Due to the significant risk of secondary malalignment, indications for lengthening by unilateral fixation have shrunken to moderate amounts of length disparity and uni- to bi-planar deformities in patients with still open physes. It represents state-of-the-art methodology and technology for complex, multi-plane deformities. Taylor Spatial Frames-built on hexapod strut-linked platform technology as known from flight simulators-took limb correction to a more reliable, more precise and aesthetical level, all the more that the whole process became web-based. In parallel, ring and wire constructs made complex three-dimensional axial, translational and rotational bone moulding possible. The initial strategy of acute or rapid incremental distraction had lasted almost half a century until Ilizarov recognised the benefits of biological periosteum-preserving osteotomies and incremental lengthening at slow rates (1 mm/day) at a 4 × 0.25-mm daily rhythm, well appreciated as callotasis. The history of surgical bone lengthening comprises 100 exciting years of struggling, development and ongoing learning. However, many patients present late or with multi-planar deformities, which warrant more sophisticated operative approaches. Timely epiphysiodesis is the best option in uniplanar deformities with adequate remaining growth and for patients whose predicted final body height is above the 50th percentile. However, their long-term acceptance is low in regard to function, costs, expenditure and appearance. Any lower limb discrepancy may be equalised by conservative means (insoles, prosthesis and orthosis).
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