TECHNIQUE

Intramedullary Pinning of Long Bones in Rabbits (Disease Investigation & Management - Treatment and Care)

Summary Information
Type of technique Health & Management / Disease Investigation & Management / Techniques:
Synonyms and Keywords See also:
Description Editor's Note: 
  • Information on this page is to be used together with information given in the "Treatment" section of the page Fractures in Rabbits and with information given in the page Treatment and Care.
  • This page is intended to provide the reader with information of particular importance for the treatment of lagomorphs. It does not provide details of the approach to different bones for pin placement.
  • The reader should use the information in this text alongside their own experience in orthopaedic surgery and should consult relevant texts on small animal orthopaedic surgery as required.
Pre-operative preparation
  • Give pre-operative analgesia 1-2 hours before surgery. (J213.5.w3)
  • Give pre-operative antibiotics 1-2 hours before surgery. (J213.5.w3)
  • Anaesthetise the rabbit. See: Treatment and Care - Anaesthesia and Chemical Restraint - Lagomorph Anaesthesia
  • Prepare the limb for surgery.
Pin placement
  • Preferably place pins normograde, avoiding damage to articular surfaces. (B601.17.w17, B602.35.w35)
    • Place normograde except in the femur. (J213.5.w3)
    • If necessary, place a cerclage wire for additional stability. (B537.1.w1)
  • For metaphyseal fractures (e.g. supracondylar femoral or humeral fractures), cross-pin with Kirschner wires. (B601.17.w17, B602.35.w35, J213.5.w3)
Nursing and post-operative care
  • See: Treatment and Care - Surgery - Post-operative care
  • Analgesia is necessary at the time of stabilisation and then continued post-operatively as necessary. (B606.10.w10)
    • Give pre-operative analgesia 1-2 hours before surgery. (J213.5.w3)
    • NSAIDs are appropriate following fracture repair. (B600.5.w5)
  • Antibiotics as necessary. (P112.1993.w1)
    • Give pre-operative antibiotics 1-2 hours before surgery. (J213.5.w3)
    • Give antibiotics for 3-5 days post-surgery. (J213.5.w3) for seven to ten days. (B606.10.w10)
  • Environment: clean and stress-free. (B606.10.w10)
    • Minimise the time in a hospital environment, which rabbits generally find stressful. (P112.1993.w1)
    • Provide a warm, quite environment. (P112.1993.w1)
  • Diet: nutritional support is important. (N12.38.w1)
    • Syringe feed with a herbivore recovery diet. (N12.38.w1)
    • Force feeding may be necessary if there is anorexia (make sure the rabbit is receiving appropriate analgesia, because pain is often manifested as anorexia). (B606.10.w10)
  • Fluids: oral or intravenous fluid therapy may be needed. (N12.38.w1)
  • Bedding: thick towels, torn-up paper or newspaper is recommended post-operatively. (J213.5.w3)
  • Monitoring (general):
    • Assess for pain.
    • Check food consumption. (J213.5.w3)
    • Check faecal output. (J213.5.w3)
    • If a splint or cast has been applied, monitor for distal swelling. (J213.5.w3)
  • Monitoring (fracture repair):
    • Re-radiograph the fracture every three to four weeks to check on the healing process. (B606.10.w10)
    • Radiograph at four weeks then every week. (P112.1993.w1)
    • Callus formation takes a minimum of ten days and an uncomplicated fracture may heal by six weeks. (B606.10.w10)
    • remove any implants only after there is radiographic evidence of fracture union. (P112.1993.w1)
    • See: Imaging in Lagomorph Diagnosis and Treatment 
Appropriate Use (?)
  • Intramedullary pins can be used to repair many fractures. (B606.10.w10)
    • Closed mid-shaft fractures of the humerus, ulna, radius, femur or tibia can be repaired using a single IM pin, together with an external splint for rotational stability. (J213.5.w3)
  • Used to achieve alignment and limit bending and rotational forces. (B601.17.w17, B602.35.w35)
  • Provide axial alignment and stabilise against bending. (P112.1993.w1)
  • Minimal tissue exposure is required for pin insertion. (P112.1993.w1)
  • Biomechanically sound - the pins share the load with the bone rather than fully protecting it from load. (B602.35.w35)
Notes
  • Pin diameter should be 60 - 70% of the diameter of the medullary cavity of the bone. (B601.17.w17, B602.35.w35)
  • Kirschner wires can be used if Steinman pins are too large. (B601.17.w17)
  • Use smooth pins; with threaded pins there is a risk of breakage at the thread interface. (B602.35.w35)
Complications/ Limitations / Risk
  • Not appropriate for use with open fractures since placing the pins may push bacteria into the bone marrow cavity. (J213.5.w3)
  • Used alone, an IM pin does not stabilise against rotation or shear. (P112.1993.w1)
    • Stack pinning, cerclage wires or additional external skeletal fixation can be used to counter shear and rotational forces. (P112.1993.w1)
  • With threaded pins there is a risk of breakage at the thread interface. (B602.35.w35)
Equipment / Chemicals required and Suppliers
  • Intramedullar pins (Steinman pins) or Kirschner wires. (B601.17.w17, B602.35.w35)

Expertise level / Ease of Use
  • This procedure should only be carried out by an individual with appropriate clinical training and practical experience.
  • Requires general anaesthesia, implants and equipment, and a degree of surgical expertise. (P112.1993.w1)
Cost/ Availability
  • Intramedullary pinning involves relatively inexpensive implants and equipment. (B602.35.w35, P112.1993.w1)

The costs of a surgical operation include those associated with: (J15.30.w1)

  • Pre-operative diagnostics (e.g. radiography, ultrasonography, blood tests)
  • Anaesthesia.
  • Perioperative medication (e.g. analgesics, antibiotics, fluids).
  • Surgical preparation (of the operating theatre and the patient, including staff time).
  • Consumables and equipment.
  • Time of the surgeon and assistant(s).
  • Post-operative hospitalisation.
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 MA VetMB PhD MRCVS (V.w5)
Referee John Chitty BVetMed CertZooMed MRCVS (V.w65)
References B601.17.w17, B602.35.w35, J213.5.w3, P112.1993.w1

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