Felis ISSN 2398-2950

Fracture fixation: plate

Synonym(s): Sherman plate, Venables plate, Burns plate, Finger plate, Dynamic Compression plate (DCP, Veterinary Cuttable Plate(VCP

Contributor(s): James Cook, Stephen Kalff, Susan Rackard, J Yovich

Introduction

  • See also Fracture: internal fixation Fracture: internal fixation.
  • To stabilize a fracture using a bone plate held in place by screws, allowing early pain-free function until healing is complete.
  • Several types of plate are available of differing design and strength. These can be broadly categorized as locking and non-locking plates.

Non-locking plates

  • Rely on a frictional interface between the bone plate and bone to create stability:
    • Hence plates must be perfectly contoured to maximize the friction at the screw/plate/bone interfaces.
  • Types: various plate designs are available, eg:
    • Dynamic compression plates (DCP) Fracture distal radius and ulna 01: repair with screw - radiograph .
    • Limited contact dynamic compression plates (LC-DCP).
    • Veterinary cuttable plates (VCP) Tibia: comminuted segmental fracture (postoperative) 01 - radiograph mediolateral  Tibia: comminuted segmental fracture (postoperative) 02 - radiograph CrCd .
    • Reconstruction plates Fracture femur 01: repair reconstruction plate - 6wks post-op - radiograph 02  Fracture femur 01: repair reconstruction plate - 6wks post-op - radiograph 01 .
    • Specialized plates, eg "acetabular", "T-plates", and "TPLO" plates, etc Fracture distal radius and ulna styloid 01: repair T plate and pin with figure of eight tension band .

Locking plates

  • Screws lock to the plate forming a fixed angle construct - a so-called "internal fixator".
  • Unlike non-locking plates, exact contouring is not necessary. Though, pre-contouring the plate minimizes plate bone gap and the working length of the screw.
  • Types: various designs are available including but not limited to the following:
    • Locking compression plates (LCP) - Sunthes.
    • String of pearl plates (SOP) - Orthomed.
    • Advanced locking plates (ALPS) - Kyon.
    • FIXIN locking plates - Trauma Vet.

Uses

Plate function

  • Compression plating:
    • Load sharing function.
    • Eccentrically loaded screws cause axial compression of the fracture interface as screws are tightened.
    • Only the DCP, LC-DCP and LCP plates are specifically designed for this:
      • Other than the hybrid LCP, this function is limited to non-locking plates.
    • Prestressing/over-contouring any non-locking plate can cause compression of the transcortex when tightening screws. This should be planned in advance to limit inadvertent suboptimal fracture reduction.
  • Neutralization plating:
    • Load sharing function.
    • Protects a primary reduction from fracture forces.
      • Eg useful to protect interfragmentary compression generated by a lag screw(s) or other device.
  • Buttress/Bridge plating:
    • Plate is subject to full loading.
    • Used in fractures where reconstruction is difficult or will result in excessive soft tissue disruption.
    • Useful in minimally invasive techniques.
    • Can be combined with an intra-medullary pin to increase the fatigue life of the plate.

Advantages

Locking plates

  • Easy to maintain primary reduction:
    • Once the screw engages the plate, no further tightening is possible, hence the implants lock the bone segments in their position.
    • As the plate doesn't need to be in intimate contact with the bone, contouring whilst remaining important is less vital than for non-locking plates.
    • For the same reason, less invasive plating techniques are easier.
  • Preservation of blood supply:
    • Locking the screw to the plate doesn't generate compression between the plate and periosteum, hence interruption of blood supply to the fracture may be minimized.
  • Stability under load:
    • Locking the screw to the plate reduces the risk of screw loosening and toggle during loading.
  • Useful in poor quality bone.

Disadvantages

Non-locking plates

  • Blood supply:
    • The dissection required to achieve compression of the plate to the bone can interrupt blood supply to the fracture site.
    • This effect is reduced with "limited contact" designs.
  • Loss of reduction:
    • Primary loss: inexact contouring of the plate can lead to dislocation of the fracture fragments as the screws tighten the bone to the plate.
    • Secondary loss: axial load can lead to "toggling" of screws (plate sliding between the screws and the bone) leading to a loss of stability.
  • Poor quality bone:
    • Poor quality bone may not withstand the compression or fraction required for stability.

Locking plates

  • Many designs have fixed angle screw holes:
    • Require planning and contouring to avoid misplacement of screws, eg intra-articular screw with juxtarticular plates.
    • Recent variable angle designs help avoid this risk.
  • Implants tend to be more expensive.

Requirements

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Preparation

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Procedure

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Aftercare

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Outcomes

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Prognosis

  • Good when correctly applied.

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Guiot L P, Déjardin L M (2011) Prospective evaluation of minimally invasive plate osteosynthesis in 36 nonarticular tibial fractures in dogs and cats. Vet Surg 40 (2), 171-182 PubMed.
  • Perren S M (2002) Evolution of the internal fixation of long bone fractures. The scientific basis if biological internal fixation: choosing a new balance between stability and biology. J Bone Joint Surg (Br) 84 (8), 1093-1110 PubMed.
  • Gentry S, Taylor R A, Dee J F (1993) The use of veterinary cuttable plates - 21 cases. JAAHA 29 (5), 455-459 VetMedResource.
  • McLaughlin R M Jr., Cockshutt J R, Kuzma A B (1992) Stacked veterinary cuttable plates for treatment of comminuted diaphyseal fractures in cats. VCOT (1), 22-25 VetMedResource.
  • Olmstead M L (1991) Complications of fractures repaired with plates and screws. Vet Clinics of North Am 21 (4), 669-686 PubMed.
  • Brüse S, Dee J, Prieur W D (1989) Internal fixation with a veterinary cuttable plate in small animals. VCOT (1), 40-46 ResearchGate.

Other sources of information

  • Piermattei D L, Flo G L, DeCamp C E (2006) Handbook of Small Animal Orthopaedics and Fracture repair. 4th edn. Saunders Elsevier, Missouri.
  • Johnson A L, Houlton J E F, Vannini R (2005) AO Principles of Fracture Management in the dog and Cat. AO Publishing.


ADDED