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Limb fracture repair: internal fixation


Introduction

  • Technique of fracture fixation.
  • Often used in combination with external coaptation as well as external fixation.
  • Principles of fracture fixation follow the same principles as in dogs and cats.

Uses

  • Surgical fixation of fractures most used for long bones.
  • Often used for fractures of the humerus and femur. Occasionally used for fixation of mandibular fractures with combination of suture material or plates and screws.
  • Intramedullary pins most used.
A full clinical exam and blood work should be performed before fracture fixation is attempted in reptiles. This is because many patients will suffer with underlying disease such as metabolic bone disease Metabolic bone disease, which makes them unsuitable patients for surgical fracture fixation.
  • Different techniques used:
    • Intramedullary pin.
    • Kirschner wire.
    • Bone plate.

Advantages

  • Intramedullary pin:
    • Easy to place.
    • Require basic orthopedic experience.
    • Low cost: hypodermic needles can be adapted as an intramedullary pin for very small patients.
    • Decreased bone exposure.
    • Can be combined with other devices such as cerclage wires.
    • Preferred method of fixation in animals that would not tolerate an external fixator.
    • Preferred fracture fixation technique in aquatic species, where external fixation will prohibit normal activity.
    • Early return to function possible.
  • Kirschner wire:
    • Occasionally used on its own for simple fractures, eg olecranon.
    • Do not require removal unless causing lameness.
  • Bone plates:
    • More control over forces acting on the bone.
    • Good fragment apposition.
    • Do not require removal unless causing discomfort.
    • Although the use of bone plates has been described in reptiles, they can be particularly difficult to fit in Chelonia due to the presence of the shell.

Disadvantages

  • Intramedullary pin:
    • Do not counteract rotational forces:
      • Only bending forces are neutralized.
      • If placed through the joint, can predispose to arthritis.
      • Higher risk of pin migration compared to mammals due to slower fracture healing.
    • Need to be removed.
  • Bone plates:
    • Require an experienced surgeon.
    • Longer anesthetic time compared to other methods.
    • Can be difficult to place in reptiles as the bone surface is sometimes more irregular compared to mammals. May need special contouring.
    • More expensive to place.
    • Thin bone cortex of many patients prohibits the use of plates and screws.
    • Possible loss of bone strength post-operatively.

Technical problems

  • Surgeon should ideally have experience of fracture fixation in other species.
  • Size of patient often makes it very challenging.
  • Pathological fractures can be difficult to fix and may require additional treatment and combination of methods.

Alternative techniques

Time required

Preparation

  • 10-20 min.

Procedure

  • Dependent on degree of reduction needed, technique chosen and size of patient.
  • For simple diaphyseal fractures with minimal displacement - 45-60 min.
  • Fixation involving comminuted fractures, open reduction, plating or combination of techniques can be lengthy - 1-3 h.

Decision taking

Criteria for choosing test

  • Simple diaphyseal fractures with minimal displacement, eg femur or humerus.
  • Small patient size prohibiting the use of plates.
  • Acute, open fractures with little to no contamination.
  • Simple mandibular fractures with no underlying pathology.

Risk assessment

  • Fracture healing in reptiles takes a long time:
    • Owners expectations should be managed.
    • Husbandry adjustment and minimal handling of the animal will be required for longer than in mammalian species.
  • If underlying conditions such as metabolic bone disease Metabolic bone disease are present, risk assessment and prognosis need to be fully discussed with the owner as further costs will be involved in husbandry correction.
  • All possible complications should be discussed with the owner to ensure ongoing cost of post-operative care, complication risk and possible need for further surgery are well communicated.
  • Patients should be stabilized before surgery:
    • External coaptation Limb fracture repair: external coaptation is often needed to stabilize fracture site before fixation.
    • Fluid therapy, nutritional and analgesia Analgesia therapy is needed.
    • Open fractures carry a high risk of osteomyelitis Osteomyelitis and require antimicrobial therapy as well as culture and sensitivity testing.
  • Fracture fixation can prove challenging and time consuming, therefore the anesthetic risk should be carefully assessed pre-operatively.

Requirements

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Preparation

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Technique

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Aftercare

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Outcomes

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Further Reading

Publications

Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Di Geronimo P M (2019) Orthopedics in reptiles and amphibians. Vet Clin North Am Exot Anim Pract 22 (2), 285-300 PubMed.
  • Castro J L C, Santalucia S, Pachaly J R et al (2014) Mandibular osteosynthesis in a Boa constrictor snake. Semina: Cienc Agrar 35 (2), 911-918 VetMedResource.
  • Di Giuseppe M, Faraci L & Luparello M (2013) Use of intramedullary pin for humeral fracture repair in a Chamaeleo chamaeleon. Natura Rerum 3, 63-69. 
  • Raftery A (2011) Reptile orthopedic medicine and surgery. J Exot Pet Med 20 (2), 107-116 VetMedResource.
  • Scheelings T F (2008) Surgical management of maxillary and mandibular fractures in an eastern Bluetongue Skink, Tiliqua scincoides scincoides. J Herpetological Med Surg 7 (4),136-140 VetMedResource.
  • Matičić D, Stejskal M, Vnuk D et al (2007) Internal fixation of a femoral fracture in a green iguana developing metabolic bone disease – a case report. Veterinarki Arhiv 77 (1), 81-86 VetMedResource.
  • Pollock C (2002) Postoperative management of the exotic animal patient. Vet Clin North Am Exot Anim Pract 5 (1),183-212 PubMed.
  • Mitchell M A (2002) Diagnosis and Management of Reptile Orthopedic Injuries. Vet Clin North Am Exot Anim Pract 5 (1), 97-108 PubMed.
  • Williams M S (2002) Orthopedic radiography in exotic animal practice. Vet Clin North Am Exot Anim Pract 5 (1), 1-22 PubMed.
  • Crane S W & Jacobsen M C (1980) Neutralization bone-plating repair of a fractured humerus in an aldabra tortoise. JAVMA 177 (9), 945-948 PubMed.
  • Pritchard J & Ruzicka A (1950) Comparison of fracture repair in the frog, lizards and rat. J Anat 84, 236-261 PubMed.

Other sources of information

  • Mader D R & Bennett R A (2