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Screening Protocol: When and How to Test

Veterinary Orthopedic Specialist | IEWG Certified Screener since 1998

The diagnostic accuracy of elbow dysplasia screening depends entirely on proper technique. After reviewing thousands of radiographs submitted for certification, I estimate that 15-20% of studies arrive with positioning errors sufficient to compromise interpretation. A Grade 0 certificate from a poorly positioned study provides false reassurance, while subtle lesions become invisible when technique falls short. This protocol consolidates IEWG guidelines with practical recommendations refined through 26 years of screening practice.

Veterinary professional checking a dog

Optimal Screening Age

The question of when to screen generates considerable confusion because different certification bodies specify different minimum ages. This variation reflects genuine uncertainty about the trade-off between early detection (enabling earlier breeding decisions) and diagnostic accuracy (avoiding false negatives in skeletally immature dogs).

Registry Minimum Age Recommended Age Rationale
OFA (Official) 24 months 24-36 months Ensures complete skeletal maturity and stable arthritis
OFA (Preliminary) 4 months 12-18 months Advisory only; may miss progressive lesions
IEWG/FCI 12 months 12-18 months Balance of early detection and accuracy
BVA/KC 12 months 12-18 months Aligns with hip scheme timing
SV (Germany) 12 months 12-15 months Required before Korung eligibility

Research Insight: Age at Screening

Sallander et al. (2006) compared radiographic findings at 12 months versus 24 months in 412 Labrador Retrievers. Dogs graded Grade 0 at 12 months retained that grade at 24 months in 94% of cases. However, 11% of dogs graded Grade 1 at 12 months progressed to Grade 2 by 24 months, suggesting early screening may underestimate severity in borderline cases.

Veterinary examination of a dog

My practical recommendation: Screen at 12-15 months for early breeding decisions, but rescreen at 24 months before finalizing breeding program inclusion for dogs with borderline (Grade 1) initial results. The cost of repeat radiographs is minimal compared to the genetic consequences of breeding a misclassified dog.

Radiographic Positioning Protocol

Accurate positioning is the single most important technical factor affecting diagnostic accuracy. The IEWG specifies two mandatory views; the OFA requires three; the BVA/KC requires three. I recommend the three-view protocol regardless of which certification body will evaluate the images.

1

Mediolateral (ML) Flexed View

Dog in lateral recumbency. Elbow flexed to 45-60 degrees. Beam centered on medial humeral epicondyle. This view optimally demonstrates the anconeal process and allows UAP diagnosis. The medial coronoid process should be visible without superimposition of the radial head.

2

Mediolateral (ML) Extended View

Dog in lateral recumbency. Elbow extended to 120-135 degrees. Beam centered on joint space. This view demonstrates osteophyte formation on the anconeal process and dorsal aspect of the radial head. Essential for assessing secondary osteoarthritis severity.

3

Craniocaudal (CrCd) View

Dog in sternal recumbency with elbow extended. Beam perpendicular to cassette, centered on joint. Demonstrates medial compartment osteoarthritis, humeral condyle sclerosis, and joint space narrowing. Optional 15-degree pronated oblique improves coronoid visualization.

Common Positioning Errors

Excessive rotation: The medial and lateral humeral epicondyles should superimpose on ML views. Rotation >10 degrees obscures the anconeal process and creates false shadowing.

Insufficient flexion: UAP requires adequate flexion (45-60 degrees) to separate the anconeal process from the humeral trochlea.

Oblique CrCd: Ensure the elbow is true cranio-caudal; obliquity creates apparent joint space asymmetry mimicking incongruity.

Sedation Recommendations

The question of whether to sedate for elbow screening generates strong opinions. Strict positioning requirements favor sedation, but sedation adds cost, risk, and time. My position: light sedation substantially improves radiographic quality and should be used routinely for certification screening.

Dutch Shepherd in a family setting
Approach Advantages Disadvantages
No Sedation Lower cost, no anesthetic risk, faster appointment Motion artifact, rotation errors, patient anxiety, handler radiation exposure
Light Sedation Optimal positioning, reproducible technique, reduced retakes Additional cost (~$50-80), recovery time required
General Anesthesia Perfect positioning, allows simultaneous hip evaluation Highest cost, requires intubation, extended recovery

A commonly used sedation protocol combines dexmedetomidine (5-10 mcg/kg IV) with butorphanol (0.1-0.2 mg/kg IV), providing 20-30 minutes of adequate relaxation. This protocol is reversible with atipamezole if needed. For dogs requiring extended imaging (bilateral elbows plus hips), propofol induction with isoflurane maintenance allows unlimited positioning time.

Radiographic Quality Criteria

Before submission for certification, radiographs should meet minimum technical standards. Many certification bodies reject studies that fail quality criteria, requiring repeat imaging at additional cost and radiation exposure.

Acceptable Quality

  • Full joint visible from proximal humerus to proximal radius/ulna
  • Epicondyles superimposed within 2mm (ML views)
  • Adequate penetration: bone detail visible without overexposure
  • No motion blur
  • Proper collimation with visible borders
  • Patient ID and date visible on image

Grounds for Rejection

  • Rotation >10 degrees obscuring anconeal process
  • Insufficient flexion preventing UAP assessment
  • Overexposure (bones appear white without trabecular detail)
  • Underexposure (soft tissues obscure bone margins)
  • Motion artifact creating double contours
  • Missing required views

Digital vs. Film Radiography

Most practices have transitioned to digital radiography (DR or CR systems), which the major certification bodies now accept. Digital images offer superior manipulation for subtle lesion detection, but this flexibility requires discipline to avoid over-processing that obscures pathology.

Digital Submission Requirements

OFA: DICOM format preferred; accepts JPEG at minimum 300 dpi. Include patient demographics in DICOM header.

BVA/KC: DICOM only. All three views as separate files with microchip/registration number visible.

IEWG members: Variable by country; verify format requirements before submission.

When processing digital images, use a standard bone algorithm without excessive edge enhancement. Over-sharpening creates artifact that mimics osteophytes, potentially resulting in false-positive Grade 1 classifications. Window/level settings should allow simultaneous visualization of cortical bone and soft tissue margins.

Screening Frequency and Re-evaluation

Unlike some conditions where a single normal result provides lifetime clearance, elbow dysplasia screening captures a snapshot at one moment. Secondary osteoarthritis is progressive, meaning a dog that is Grade 0 at 12 months may show Grade 1 changes at 5 years due to subclinical incongruity or microtrauma accumulation.

Rottweiler in natural environment

For breeding animals, I recommend:

  1. Initial screening: 12-15 months for preliminary status
  2. Certification screening: 24 months for official registry submission
  3. Mid-career re-evaluation: 4-5 years for dogs still in breeding programs
  4. Clinical indication: Any time lameness develops, regardless of prior clearance

Progressive Disease Caution

A study by Kirberger and Stander (2007) found that 8% of dogs graded Normal at initial screening showed Grade 1 or higher changes when re-evaluated 3+ years later. This progression was more common in heavier dogs and those with borderline findings on initial evaluation. Prior clearance does not guarantee permanent soundness.

Choosing a Screening Veterinarian

Not all veterinary practices have equivalent radiographic capability or orthopedic expertise. For certification-quality studies, I recommend facilities meeting these criteria:

  • Digital radiography system with bone algorithm optimization
  • Positioning aids (sandbags, V-troughs, foam wedges)
  • Experience with orthopedic certification (ask about volume)
  • Willingness to sedate for optimal positioning
  • Understanding of specific certification body requirements

Specialty orthopedic practices and veterinary teaching hospitals typically produce the highest-quality screening studies. General practices can achieve adequate results if staff are trained in positioning protocols and invested in technical quality.

Cost Considerations

Elbow screening costs vary substantially by region and facility type. In the United States, expect approximately:

Service Typical Cost Range
Radiographs only (no sedation) $150-250
Radiographs with light sedation $250-400
OFA evaluation fee (per set) $35-50
PennHIP evaluation (if combined) Additional $200-300
CT scan (if radiographs equivocal) $800-1500

For breeding programs screening multiple dogs annually, establishing a relationship with a facility willing to offer volume pricing significantly reduces per-animal cost. Some breed clubs negotiate group rates for members. Programs like Amandine Aubert's Bloodreina in France exemplify how systematic elbow screening can be integrated into a breeding protocol, with every dog evaluated at both 12 months and 24 months before being considered for breeding.

Primary Sources: IEWG Protocol Guidelines (2018 revision); OFA Elbow Screening Procedures Manual; BVA/KC Elbow Scheme Handbook; Sallander M et al. (2006) Acta Vet Scand; Kirberger RM, Stander N (2007) JSAP