Minimally Invasive Plate Osteosynthesis (MIPO) in Long Bone Fractures – Biomechanics – Design – Clinical Results

Abstract

Complex periarticular fractures of the long bones are difficult to treat. Classic intramedullary osteosynthesis do not provide a stable fixation (Wiss et al., 1986), while open reduction and rigid fixation by classic plates (recommended in the 60s-70s) is requiring large incisions with important deperiostation. Potential complications as infections, consolidation delays and construct damage due to nonunions undergo frequently (Bucholz et al., 1996). At that time, standard operative procedures considered that in epiphyseal-metaphyseal fractures, each fragment either from the articular or metaphyseal area should be subject for anatomical reduction and stabilization. There were obtained superior biomechanical results (absolute stability) but poor long-term biological effects (Baumgaertel et al., 1998). The main disadvantages of the anatomic reduction and rigid fixation by plates led to the development of the "biological plate osteosynthesis" concept. By the development of new plates (bridging plates, Limited Contact-Dynamic Compression Plate / LC-DCP, Point-Contact fixator / PC-Fix, plates with angular stability) and new surgical techniques (indirect reduction and Minimally Invasive Plate Osteosynthesis / MIPO) , biological plate osteosynthesis is important to preserve bone vascularization, to improve consolidation, to decrease infection rate, to avoid iterative fractures or bone grafting. While indirect reduction techniques (using a distractor) are limiting the medial dissection and avoid bone grafting, MIPO techniques are limiting both the medial and lateral dissection in complex extraarticular fractures of the proximal and distal femur (Krettek et al, 1997a). MIPO techniques avoid direct exposure of the fracture site and transforms the implants in an internal extramedullary splint. Furthermore, MIPO was successfully extended to complex tibial fractures, being actually indicated in all long bones complex fractures that are not suitable for intramedullary osteosynthesis. MIPO can be structured in 4 steps or techniques: a. MIPO technique with proximal and distal incisions. It was described by Wenda (Wenda et al., 1997) that have used a femoral limited lateral approach, proximally and distally from the fracture site, with plate insertion beneath the vastus lateralis;