Patient-specific three-dimensional (3-D) cutting guides and custom plates in the management of tibia and femur malunion - an update.

Malunion of the lower limb long bones is a significant complication following the operative and nonoperative management of fractures. Malunion can manifest as a simple uniplanar deformity or a complex multiplanar deformity, including angular, rotational, translational, and length discrepancies. The current gold standard is osteotomy correction. After thorough clinical assessment of deformity including rotational alignment, the deformity is further assessed using two-dimensional(2D) radiographs and computer-aided tomography (CT) scans reserved for intra-articular deformities. During surgery fluoroscopy control, and visual inspection of the limb, particularly to assess rotation are the tools to assess correction. Finally standard off-the-shelf plates and nails are used to stabilise the bone. However, these methods have inherent limitations in treating complex deformities. Recent advances in three-dimensional (3D) image processing, the ability to perform virtual osteotomies and corrections, and additive manufacturing technologies have enabled the creation of patient-specific cutting guides that allow precise and predictable osteotomy correction and patient-specific implants. Although they are becoming popular, evidence of their safety, efficacy, and superiority over the gold standard methods is limited. Current literature is heterogenous and consists of case reports, short case series, technical notes and mainly retrospective studies. We present an update based on the current literature focusing on the efficacy and accuracy of 3D printed jigs, complication profile, functional and patient reported outcomes and comparison with conventional methods where available to help limb reconstruction surgeons make decisions and guide patients.