Plate Osteosynthesis

Principles of Plate Osteosynthesis - Metal Meets Bone

• Plate Osteosynthesis: Surgical fracture fixation with plates/screws for anatomical restoration.
• AO Principles:
  • Anatomic reduction: Precise fragment realignment.
  • Stable fixation: Absolute or relative.
  • Blood supply preservation: Minimize soft tissue trauma.
  • Early mobilization: Safe, active movement.
  • 📌 Mnemonic: ASBE (Absolute Stability, Blood supply, Early mobilization).
• Constructs:
  • Load-sharing: Plate & bone share load.
  • Load-bearing: Plate bears entire load.
• Healing:
  • Primary: Absolute stability, no callus.
  • Secondary: Relative stability, callus.

⭐ Absolute stability (rigid plate) → primary bone healing (minimal callus). Relative stability (bridging plate) → secondary bone healing (callus).

Types & Functions of Plates - The Right Fit

• Plate Types:

  • DCP (Dynamic Compression Plate): Oval holes → compression.
  • LC-DCP (Limited Contact DCP): Undercut, ↓vascular injury.
  • LCP (Locking Compression Plate): Locking/non-locking screws; angular stability. Internal fixator.
  • Reconstruction: Malleable (pelvis).
  • Tubular (1/3, 1/4): Low-stress (fibula).
  • Specialty: Anatomical (PHILOS, condylar buttress).

• Plate Functions: 📌 (CNBBT)

  • Compression: Static (prebend)/dynamic (eccentric screw).
  • Neutralization: Protects lag screws.
  • Buttress: Supports articular fragments (tibial plateau).
  • Bridging: Spans comminution; length/alignment.
  • Tension Band: Tension → compression.

• DCP vs. LCP:

  Feature	DCP	LCP
  Mechanism	Friction	Angular stability (int. fixator)
  Screw I/F	Plate compresses bone	Screws lock to plate
  Stability	Relative (axial)	Absolute (angular)
  Blood	↓ contact	↑ preserved (min. contact)
  Indication	Simple #, good bone	Osteoporotic, comminuted periart. #

⭐ LCPs: internal fixators, angular stability independent of plate-bone friction. Ideal for osteoporotic bone & comminuted periarticular #.

Indications & Contraindications - Plating Go/No-Go

Indications (Go):

• Articular Fx (anatomic reduction, abs. stability): e.g., tibial plateau, distal radius.
• Diaphyseal Fx: Forearm (gold standard), humerus, femur, tibia.
• Periarticular Fx, osteotomies, nonunion/malunion.

Contraindications (No-Go):

• Absolute: Active infection, severe soft tissue compromise.
• Relative: Severe osteoporosis, unfit for surgery, high comminution (IMN better), non-compliance.

Open Fractures (Gustilo-Anderson):

• Type I & II → primary plating; Type III → staged.

⭐ Plating of both-bone forearm fractures in adults is the gold standard to restore rotational stability (pronation/supination).

Surgical Technique - Plating Playbook

• Pre-op: Templating, implant selection.
• Approach: Meticulous soft tissue handling (preserve blood supply).
• Reduction: Direct/Indirect. Provisional K-wires.
• Plate: Type/length selection. Contour (DCP vital; LCP less if internal fixator).
• Screws: Lag (interfragmentary compression); DCP (eccentric drilling for compression). Conventional: 3-4 bicortical screws/6-8 cortices per main fragment. LCP: 3 locking screws/fragment. Length: perforate far cortex 1-2mm.
• Intra-op Imaging: Confirm reduction & hardware.

⭐ To achieve compression with a DCP, the screw is inserted into the eccentric portion of the oval hole, away from the fracture line; tightening the screw then draws the bone fragment towards the fracture.

Complications - Plate Pitfalls

• Intraoperative: Neurovascular injury, iatrogenic fracture.
• Early Postop: Infection (superficial/deep), hematoma, wound dehiscence, compartment syndrome.
• Late Postop:
  • Implant failure (bending/breakage, screw pull-out/loosening).
  • Biological failure (nonunion, malunion, delayed union).
  • Refracture (post-plate removal), stress shielding & osteopenia, hardware irritation.
• Prevention: Asepsis, gentle tissue handling, stable fixation.
• Management (Key):
  • Infection: Debridement, antibiotics, ?implant removal.
  • Nonunion: Bone grafting, revision fixation.

⭐ Stress shielding under a very rigid plate can lead to cortical osteopenia beneath it, ↑ risk of refracture after implant removal if bone hasn't fully remodeled.

High‑Yield Points - ⚡ Biggest Takeaways

• Plate osteosynthesis provides absolute stability, crucial for direct (primary) bone healing.
• Dynamic Compression Plates (DCP) achieve compression via eccentric screw drilling.
• LC-DCP reduces plate-bone contact, better preserving periosteal blood supply.
• Locking plates create a fixed-angle construct, acting as an internal fixator, vital for osteoporotic or comminuted fractures.
• Key indications: articular fractures, forearm fractures, and osteotomies.
• Stress shielding beneath the plate can cause osteopenia and risk of refracture post-removal.