Tibial Lengthening with a Motorized Intramedullary Lengthening Nail.

Background: Tibial lengthening with use of a motorized intramedullary lengthening nail (MILN) provides precise deformity correction and distraction osteogenesis without requiring external fixation Description: The preoperative patient evaluation starts with a history to understand the primary reason(s) that the patient seeks lengthening, to identify potential care challenges (such as dormant infection for patients with a post-infectious etiology or joint instability for patients with limb deficiency). The physical examination should evaluate for joint contracture or instability, spasticity, prior surgery compromising the surgical approach, and patient psychological or physical capacity to comply with postoperative weight-bearing and lengthening instructions. Preoperative imaging includes calibrated orthogonal radiographs of the operative tibia to ensure suitable anatomy and bilateral hip-to-ankle radiographs, with blocks to level the pelvis as needed, to determine any limb-length discrepancy (LLD) or alignment deformity Alternatives: Some LLD cases are suitably treated without surgical intervention Rationale: LLD and associated deformities can alter natural gait patterns and lead to abnormal joint forces, which may cause a painful and altered gait. Although there are broad opinions regarding the minimum LLD indicating surgery, distraction osteogenesis is a well-established and proven mechanism for bone lengthening. Once lengthening has been indicated, many factors influence the decision to use external or internal fixation, such as the magnitude of lengthening, need and ability to correct other deformity, implant access, and non-medical patient factors. Regardless of the implant, tibial osteotomy should be performed utilizing safe planning, techniques, and medical adjuncts Expected Outcomes: When an MILN procedure is performed safely, patients can expect up to 8 cm of lengthening with a minimal risk of implant problems, fracture, infection, or other adverse events Important Tips: Establish the LLD before surgery, then rely on the machine to determine the length achieved; do not second-guess the machine during lengthening.Correct or prevent rotational, coronal, and sagittal deformity at the time of the MILN insertion surgery.Prioritize safety (i.e., with a percutaneous technique, fasciotomy, and tranexamic acid) to optimize outcomes (i.e., avoidance of complications and achievement of the desired length).Ensure patient compliance with weight-bearing limitations and stretching exercises.Limit weight-bearing until at least 3 cortices have full bridging.MILN removal is recommended after full union is achieved, typically approximately 1 year postoperatively. Acronyms and Abbreviations: LLD = limb-length discrepancyMILN = motorized internal lengthening nailPT = physical therapyIM = intramedullary.