Species: Canine   |   Classification: Techniques

Introduction Requirements Preparation Procedure Aftercare Outcomes Further Reading

Introduction

  • Arthrography is a radiographic study of a synovial joint where iodine-based contrast medium is injected into the joint space.

Uses

Indications and contraindications for contrast arthrography

  • The only synovial joint where a contrast arthrography is relevant in the dog is the shoulder joint. The following discussion will focus on shoulder arthrography.
  • Relative indications:
    • Shoulder OCD Shoulder: osteochondrosis - arthrogram : investigate presence of attached OCD flap.
    • Suspected bicipital tenosynovitis and/or avulsion Rupture / avulsion of the biceps brachii tendon .
    • Suspected biceps tendon luxation or rupture Shoulder: chronic biceps tendon avulsion - arthrogram.
    • Joint capsule integrity in shoulder trauma.
    • Assessment of joint neoplasia and cartilage erosion.
  • There is no absolute indication for shoulder arthrography in the dog.
  • Contraindications for shoulder arthrography include known iodine allergies or increased risks associated with needle insertion (bleeding disorder, tumor seeding).

Advantages

  • The main advantage is the visualization of articular cartilage and intra-articular tendons/ligaments which cannot be differentiated on survey radiographs.
  • Negative contrast medium (gas) is not commonly used but can occur naturally with extensive distraction (cavitation) or post-operatively.

Decision Taking

Criteria for choosing test

  • Is the examination appropriate?
  • Can you make the diagnosis without it?
  • Will your management of the case be affected by the outcome of the examination?

Requirements

Materials Required

Minimum equipment

  • X-ray machine.
  • Cassette.
  • Processing facilities.
  • Protective clothing (lead apron) for radiographer.
  • Positioning aids (sandbags, cradle and ties).
  • Method of labeling film.
  • Equipment for sterile joint injection and synoviocentesis.

Ideal equipment

  • Ability to process films during procedure so that repeat radiographs can be taken during course of study if required.
  • High output X-ray machine.
  • High definition screen.
  • Grid for examination of large dog.

Minimum consumables

  • Radiographic film.
  • Contrast medium:
    • Use non-ionic contrast medium, eg Iohexol, Iopamidol, Ioversol.
    • Concentration: 100-150 mg Iodine/ml. Dilute contrast medium with sterile saline to required iodine concentration (most contrast media come in higher concentrations). Higher iodine concentrations can be detrimental to the quality of the study.
    • Dose: 1.5-4 ml/joint depending on the size of the dog and whether just the shoulder joint or also the bicipital tendon sheath is to be imaged.
  • Equipment for sterile joint injection, synoviocentesis and synovial fluid analysis.

Preparation

Other Preparation

Procedure

Approach

Step 1 - Survery films

  • Check exposure settings and processing.
  • Confirm positioning adequate.
  • Confirm diagnosis not apparent without contrast study.
  • The trachea should not be superimposed on the shoulder joint. Extend the neck to allow a more dorsal location of the trachea.

Step 2 - Sterile synoviocentesis and contrast medium injection

  • Two person job: one person injects and the other assists with positioning and syringe handling.
  • Dog in lateral recumbency with relevant shoulder joint up and partially flexed.
  • Surgical preparation of craniolateral shoulder area.
  • Rotate humerus slightly externally (supination) and apply distal traction.
  • Use 20/22 G, 1.5/2 inch long needle. Attached three-way-tap with two syringes (one empty, one with contrast medium) recommended for synovial fluid analysis Synovial fluid: sampling.
  • Landmarks: two possible approaches:
    • A) Insert needle a few mm cranial and distal to the acromion of the scapula and directly caudal to the greater tubercle of the humerus. The needle should point towards caudal, slightly medial and slightly distal.
    • B) Insert needle directly medial to the most distal aspect of the supraglenoid tubercle of the scapula. The needle should point towards caudal and slightly dorsal.
  • A slight pop can often be felt when entering the joint capsule. Aspirate synovial fluid to prove correct location. Synovial fluid analysis is recommended.
  • Inject contrast medium, withdraw needle and apply local pressure to prevent leakage.
  • Manipulate shoulder for 20-30 sec to distribute contrast medium.
  • Lateral and craniocaudal radiographs should be obtained within 5 min of injection.

Aftercare

Immediate

Monitoring

  • Ensure that no contrast medium or blood is leaking from injection site.
  • Post-anesthetic recovery.

Analgesia

  • Not usually required.

Antimicrobial therapy

  • Only required if sterility was questionable or if a septic arthritis Arthritis: septic is suspected.

Potential complications

  • Non-diagnostic study:
    • Contrast medium concentration to high: high opacity of contrast medium makes it impossible to see filing defects in cartilage or tendons.
      Very common mistake.
      • Remedy: repeat radiographs after 5 min until appropriate contrast medium dilution has occurred.
    • Mis-injection into periarticular structures:
      • Remedy: repeat needle injection with alternative landmark approaach.
    • Biciptal tendon sheath not filled with contrast media. This could be caused by an insufficent volume or a maldistribution of contrast medium (stricture, mass, hematoma):
      • Remedy: manipulate shoulder and repeat films, add injection volume, inject directly into biceps tendon sheath.

Outcomes

Complications

  • Sterile or septic synovitis:
    • There is an increased risk of sterile synovitis if ionic contrast media are used (not recommeded).
  • Pain:
    • If multiple attempts of needle insertion were taken or if there was substantial cartilage damage done with the needle tip.
    • With commonly bilateral shoulder OCD, increased post-procedure weight-bearing on contralateral limb might exacerbate pain there.

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Clements D N, Kelly D F, Philbey A W et al (2005) Arthrographic diagnosis of shoulder joint masses in two dogs. Vet Rec 156 (8), 254-255 PubMed.
  • van Bree H & van Ryssen B (1995) Positive contrast shoulder arthrography with iopromide and diatrizoate in dogs with osteochondrosis. Vet Rad & Ultrasound 36 (3), 203-206 VetMedResource.
  • Barthez P Y & Morgan J P (1993) Bicipital tenosynovitis in the dog - evaluation with positive contrast arthrography. Vet Rad & Ultrasound 34 (5), 325-330 VetMedResource.