Minimally invasive plate osteosynthesis MIPOwhen to use it

Minimally invasive plate osteosynthesis (MIPO)―when to use it? AO Trauma Basic Principles Course

Learning objectives • Describe the concept and principles of the minimally invasive plate osteosynthesis (MIPO) technique • Discuss the bridge plating concept, including the biological and biomechanical principles • Realize that simple fracture treated with MIPO technique are more demanding to reduce • List the risks and benefits of MIPO

MIPO principles • Approach the bone far from the fracture zone • Indirect reduction of the fracture • Direct reduction if needed • Flexible fixation in comminuted fractures • Stable fixation in simple fractures

MIPO is MIO Definition MIO • Stabilization of a fracture using indirect reduction technique • fracture fixation with implants inserted through soft tissue windows away from the fracture zone Forms of minimally invasive stabilization techniques • MIPO: extramedullary splinting • IM nailing: intramedullary splinting • External fixator: extracorporal splint

Concept of minimally invasive plate osteosynthesis (MIPO) • Careful handling of soft tissue through small soft-tissue windows • Indirect reduction of the fracture (alignment, axis, and rotation) especially in comminuted fractures • Percutaneous or “mini open” direct reduction in simple fractures if needed • Maintaining reduction for C-arm control • Flexible fixation in comminuted fractures and stable fixation in simple fractures

MIPO shaft Soft-tissue window: • Far from the fracture site • Large enough to see, palpate, and fix the plate

MIPO fracture site • • Little additional trauma if direct reduction is needed • Percutaneous (close to fracture or at the fracture) • “Mini open” in simple fractures for anatomical reduction (absolute stability) Use instruments that leave small “footprints” Percutaneous or mini open

Bridge plating • Long plate to distribute forces (six holes on each side if possible) • Acts as an extramedullary splint • Fixation with bicortical screws, minimum three in each fragment • Provides relative stability

Bridge plating Comminuted fractures • Screws placed close to the fracture Simple fractures • Screws 1– 2 holes away from the fracture Relative stability

Compression plating Simple fractures Percutaneous anatomical reduction with percutaneous lag screws or Mini open anatomical reduction and lag screw application 6 month Mini open Absolute stability 10

Reduction in MIPO Indirect reduction by • Traction along the axis of the limb • Force application remote from the fracture site • Soft-tissue envelope helps reduction

Reduction in MIPO Direct reduction • Direct force applied at the fracture site • Percutaneously or mini opening

Maintaining reduction in MIPO • Traction table • External fixator • Forceps • Cerclage • Screw • Plate

Reduction control—needs a stable operative field Adjuncts • Temporary fixation • K-wire, Schanz screw, drill bit, clamps, plate • Cable • Prevent malunion

Indication for MIPO • Periarticular fractures • Joint level: anatomical • Shaft: aligned (length, axis, and rotation) • No nail possible • Narrow, deformed, or occupied canal (implant) • Open physis • Trauma load (ISS), pelvis • Soft-tissue conditions

Benefits • Bone healing less disturbed • Infection rate decreased • Less bone graft needed • Operation time decreased • Less pain • Faster rehabilitation • Cosmetic appearance

Risks • Limited view • Increased C-arm time • Malunion • Delayed/nonunion • Demanding technique with important learning curve

Take-home messages • Approach through soft-tissue windows • Indirect reduction • Percutaneous (mini open) direct reduction (tools) • Maintenance of reduction (x-ray control) • Elastic fixation in bridge plate concept • Stable fixation in simple fracture pattern • Selected indications