Flexible fixation and fracture healing: do locked plating 'internal fixators' resemble external fixators?

Area of Science:

• Orthopaedic Surgery
• Biomaterials Science
• Skeletal Biology

Background:

• External and internal fixators utilize bone screws locked to plates or bars to prevent periosteal compression and maintain blood supply.
• Both osteosynthesis techniques primarily rely on secondary bone healing via callus formation, except for compression plating of simple fractures.
• These "biologic" osteosynthesis methods enable minimally invasive approaches, preserving fracture hematoma and periosteal blood supply.

Purpose of the Study:

• To compare the biomechanical properties and clinical applications of external and internal fixators in osteosynthesis.
• To highlight the differences in stabilization principles and healing outcomes between the two fixation methods.
• To discuss the advantages and limitations of each technique in various fracture scenarios.

Main Methods:

• Review of osteosynthesis techniques focusing on locked plating (internal fixators) and external fixation systems.
• Analysis of biomechanical principles including buttressing, dynamic compression, and stiffness.
• Examination of applications in articular fractures, pediatric cases, and specific indications like distal radius fractures.

Main Results:

• Locked plating allows for buttressing and dynamic compression, offering greater biomechanical stiffness due to plate proximity to bone.
• Periarticular locking plates are anatomically contoured for articular fractures, enabling subchondral stabilization and buttressing.
• External fixators are less expensive, flexible, and technically less demanding, suitable for emergent stabilization and specific indications.

Conclusions:

• Internal locked plating provides superior biomechanical stability, particularly for complex fractures, while external fixation offers cost-effectiveness and flexibility.
• Both methods support biologic healing, but the choice depends on fracture type, location, patient factors, and desired biomechanical outcome.
• External fixators remain crucial for emergent stabilization, pediatric fractures, and specific osteosynthesis needs, including callus distraction.