TECHNIQUE

Internal Skeletal Fixation in Birds (Disease Investigation & Control - Treatment and Care)

Summary Information
Type of technique Health & Management / Disease Investigation & Control / Treatment & Care / Techniques:
Synonyms and Keywords Intramedullary Pinning, Stainless Steel Intramedullary Pins, Orthopaedic Wires, Polypropylene rods, Absorbable IM Pins, Intramedullary Polymethylmethacrylate, Bone plates (J2.23.w2, B12.42.w5).
Description Detailed descriptions of the principles of internal fixation and of the use of these procedures for fracture repair are given in general orthopaedic surgery texts. Further information on application to avian fractures and surgical approaches to different bones are given by Bennett & Kuzma (J2.23.w2), Harcourt Brown (B11.16.w13) Simpson (B11.17.w14), Bennett (B12.42.w5), Martin and Ritchie (B13.42.w15), Coles (B14) MacCoy (P7.1.w5); the following notes are intended as an indication of their potential use.
  • Coracoid - IM pin.
  • Humerus - IM pins; stack pin technique may be used. Cerlage wires may provide additional stability (B11.17.w14). Harrison/Doyle impaction technique; polymer rod (shuttle pin)(B14). May be used in combination with external fixators (B11.17.w14, B13.42.w15). Bone plate may also be used (B12.45.w5)
  • Distal or proximal metaphyseal fracture of the humerus -Rush pin (P7.1.w5)
  • Radium & ulna - IM pin, or IM shuttle pin (B11.17.w14)
  • Proximal femur - tension band (B11.16.w13);IM pins (B13.42.w15).
  • Femur - IM pin or pins & wires, shuttle pin (B11.16.w13, B12.42.w5, B13.42.w15); plate (B12.42.w5, B13.42.w15).
  • Femoral condyles - cross pins (B11.16.w13)
  • Tibiotarsus - stack pinning plus external splint (B11.16.w13). Bone plates have been used in large birds (B13.42.w15).
  • Proximal tibiotarsus - pin and wire (B11.16.w13).
  • Distal tibiotarsus - cross pins (B11.16.w13).
  • Tarsometatarsus - IM pin. Small plate (B13.42.w15)
  • Distal tarso-metatarsus - cross pins (B11.16.w13)

(J2.23.w2, B11.16.w13, B11.17.w14, B12.42.w5, B13.42.w15).

Appropriate Use (?)
  • Treatment of some Impact Injuries, Crushing.
  • Orthopaedic wires - in conjunction with an intramedullary pin, providing stabilisation of long oblique and spiral fractures against shear and rotation forces, and to hold bone fragments.
  • Bone plates: May be useful in larger birds with relatively thick cortices. Allow anatomic alignment, provide rigid stabilisation, avoid interference with joint motion, allow early return to function. May allow primary bone healing with little or no callus. May be used for repair of closed fractures. May be used for open fractures (B12.42.w5); not recommended for use in open fractures as may become a nidus for infection (B13.42.w15).
  • High density polymer rods. - diaphyseal fractures with little or no contamination or comminution (B12.42.w5).
  • Doyle technique / modified Harrison-Doyle technique - pins do not pass through joints or damage periarticular tissue. Provide maximum compression of the fracture site (B13.42.w15, B14).

(J2.23.w2, B12.42.w5, B13.42.w15, B14).

Notes
  • Intramedullary Pins: Provide bending stability and axial alignment, require minimum tissue exposure for insertion. May be used with cerclage wires or hemicerclage wires to stabilise against shear and rotation forces, or may be used in a stacking pin technique. If placed through/near a joint, should be removed as soon as possible. Recommended size to fill 50-60% of medullary cavity.
  • Rush pin and cross pin techniques: for metaphyseal fractures
  • High density polymer rods. light weight biologically inert, do not need to be removed, very stable. Rotational stability may be increased by inserting a Kirschner wire through the bone and pin on either side of the fracture, but this predisposes to fracture through these sites. May also be used with external skeletal fixation, and with intramedullary methylmethacrylate.
  • Intramedullary methylmethacrylate. May be useful for corrective osteotomy, closed fractures, open fractures with minimal contamination and no exposed necrotic bone. May be used with polymer rod IM pins or steel pins to provide rotational stability and increase bending resistance. Requires precise timing and co-ordination of use
  • Absorbable IM pins (PDS - Polydioxanone) - completely absorbed within 6 months. less stiff than stainless steel pins, may be larger callus formation., may need external coaptation. Do not need removing, but technically difficult to insert.
  • Bone plates. Relatively little used in avian orthopaedics. Removal of plate may not be necessary.
  • Doyle technique / modified Harrison-Doyle technique - combines intramedullary support of Rush pin technique with external fixation.

(J2.23.w2, B12.42.w5, B13.42.w15, B14, P7.1.w5).

Complications/ Limitations / Risk
  • Require general anaesthetic, which may be prolonged.
  • Success is often dependant on the skill and experience of the surgeon.
  • In use on a closed fracture, creates an open fracture, with an increased risk of osteomyelitis and of compromising the blood supply to the fracture.

For specific methods of repair:

  • Intramedullary Pins: Not stable against rotation and shear forces; overriding may occur with oblique fractures. Frequently placed through articular surfaces or near a joint; resultant damage to articular and periarticular structures may inhibit normal joint function.Also interfere with the production of endosteal callus and endosteal bone. Heavy and should be removed or may prevent flight.
  • Orthopaedic wires: require great care or may produce iatrogenic fracture. Do not provide support against bending forces.
  • High density polymer rods. Inserted with shuttle technique - limits length that may be used. Less rigid than steel, may allow micromotion at the fracture site and this may delay healing. Difficult to remove once inserted - unsuitable for open fractures where may serve as nidus for infection. Experience required for proficient use of shuttle technique.
  • Intramedullary methylmethacrylate. high temperatures during causing cause osteocyte death and bone necrosis - may be cooled with water. If infected, acts as a chronic focus for infection - may be used with antibiotics incorporated, but this reduces strength and the long-term effects are not known. Not suitable alone for use in birds weighing more than 500grams. Not suitable for use in infected/contaminated fractures. Brittle, may break at fracture site.
  • Bone plates. Technically difficult, requires specialised training, extensive surgical exposure and prolonged anaesthetic time. Equipment specialised and expensive. May become nidus for infection. Potential for stress protection, cold sensitivity, delayed fracture healing. Risk of fracture, particularly through screw holes, when plate removed.
  • Doyle technique / modified Harrison-Doyle technique - Smallest fracture segment must be sufficiently large to allow the placement of a stabilizing pin. Do not stabilise against rotation or prevent over-riding.

(J2.23.w2, B12.42.w5, B13.42.w15, B14).

Equipment / Chemicals required and Suppliers
  • Appropriate surgical equipment, including e.g. Intramedullary pins, Kirschner wires, orthopaedic wire, high density polymer rods, methylmethacrylate, bone plates and screws.
  • Bone plates: Equipment is specialised and expensive.
Expertise level / Ease of Use
  • Procedure should only be undertaken by an individual with appropriate clinical training and practical experience; this would usually be a veterinarian Surgical expertise is required, which may be very advanced (extent depends on method used).

(J2.23.w2, B12.42.w5).

Cost/ Availability
  • Variable availability and expense - some very expensive
  • Bone plates. Equipment specialised and expensive.
  • High density polymer rods. Light weight, readily available, easily sterilised, inexpensive. May be constructed from the plunger of a disposable hypodermic syringe. Biologically inert, do not need to be removed, very stable. 

(J2.23.w2, B12.42.w5, B14).

Legal and Ethical Considerations In some countries there may be legislation restricting the use of this type of technique to licensed veterinarians. For example in the UK: "The Veterinary Surgeons Act 1966 (Section 19) provides, subject to a number of exceptions, that only registered members of the Royal College of Veterinary Surgeons may practice veterinary surgery."(see: LCofC1 - RCVS Guide to Professional Conduct 2000 - Treatment of Animals by Non-Veterinary Surgeons).).
Author Debra Bourne
Referee  
References J2.23.w2, B11.16.w13, B11.17.w14, B12.42.w5, B13.42.w15, B14, P7.1.w5

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