Hip Dysplasia & FAI Measurements (LCEA / Tönnis / Alpha / Neck-Shaft) — free guideline decision tool
LCEA, Tönnis angle, alpha angle, neck-shaft angle, femoral version and joint space for dysplasia, pincer/cam impingement and hip-preservation suitability. Includes how to measure and what each value means. Instant, browser-side.
Open guideline tool →Guideline-based
Implements the decision logic from published clinical guidelines.
Runs in your browser
No installation. Enter the patient's values and get a guideline recommendation instantly.
Data stays local
Nothing is uploaded. Results are for licensed clinicians only.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Lateral center-edge angle | 28 ° |
|---|---|
| Tönnis angle | 8 ° |
| Alpha angle | 62 ° |
| Neck-shaft angle | 130 ° |
| Femoral version | 15 ° |
| Minimum joint space width | 3.5 mm |
→Alpha angle62°
- Lateral center-edge angle：28 ° → 25–39°: normal
- Tönnis angle：8 ° → 0–10°: normal
- Alpha angle：62 ° → > 55°: cam morphology (> 60° more specific)
Common questions
What is Hip Dysplasia & FAI Measurements (LCEA / Tönnis / Alpha / Neck-Shaft)?
LCEA, Tönnis angle, alpha angle, neck-shaft angle, femoral version and joint space for dysplasia, pincer/cam impingement and hip-preservation suitability. Includes how to measure and what each value means. Instant, browser-side.
How is Hip Dysplasia & FAI Measurements (LCEA / Tönnis / Alpha / Neck-Shaft) calculated? What is the core formula?
Lateral center-edge angle < 20°: acetabular dysplasia Lateral center-edge angle 20–25°: borderline dysplasia Lateral center-edge angle 25–39°: normal Lateral center-edge angle ≥ 40°: overcoverage (pincer FAI) Tönnis angle < 0°: overcoverage (pincer) Tönnis angle 0–10°: normal Tönnis angle > 10°: dysplasia (steep sourcil) Alpha angle ≤ 55°: normal Alpha angle > 55°: cam morphology (> 60° more specific) Neck-shaft angle < 120°: coxa vara Neck-shaft angle 120–140°: normal (mean ~125–135°) Neck-shaft angle > 140°: coxa valga Femoral version < 5°: decreased version / retroversion (worsens impingement) Femoral version 5–25°: normal range (mostly 10–20°) Femoral version > 25°: excessive anteversion (worsens instability) Minimum joint space width < 2 mm: marked narrowing — poor hip-preservation outcome Minimum joint space width 2–3 mm: mild narrowing Minimum joint space width ≥ 3 mm: normal
When is Hip Dysplasia & FAI Measurements (LCEA / Tönnis / Alpha / Neck-Shaft) used?
Hip (adult) imaging: AP pelvis, Dunn view, CT/MRI — dysplasia, FAI and hip-preservation assessment.
What are the key clinical points for Hip Dysplasia & FAI Measurements (LCEA / Tönnis / Alpha / Neck-Shaft)?
Standard AP pelvis (coccyx tip over the symphysis, 1–3 cm). Each value is graded against published reference ranges. Measurement technique and positioning change the numbers — compare like with like on follow-up. Part of the YuanDoctor MSK measurement topic.
What are the limits and cautions when using Hip Dysplasia & FAI Measurements (LCEA / Tönnis / Alpha / Neck-Shaft)?
For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
Does Hip Dysplasia & FAI Measurements (LCEA / Tönnis / Alpha / Neck-Shaft) upload patient data? Where is it calculated?
Calculation runs locally in the browser; inputs and results are not uploaded. For licensed clinicians only; interpret with history, investigations and local protocols — not a diagnosis or prescription.
How is Hip Dysplasia & FAI Measurements (LCEA / Tönnis / Alpha / Neck-Shaft) calculated in practice? Can you show a worked example?
Inputs: Lateral center-edge angle 28 °, Tönnis angle 8 °, Alpha angle 62 °, Neck-shaft angle 130 °, Femoral version 15 °, Minimum joint space width 3.5 mm → Result: Alpha angle 62 °（Lateral center-edge angle: 28 ° → 25–39°: normal, Tönnis angle: 8 ° → 0–10°: normal, Alpha angle: 62 ° → > 55°: cam morphology (> 60° more specific)）
Run Hip Dysplasia & FAI Measurements (LCEA / Tönnis / Alpha / Neck-Shaft) now
LCEA, Tönnis angle, alpha angle, neck-shaft angle, femoral version and joint space for dysplasia, pincer/cam impingement and hip-preservation suitability. Includes how to measure and what each value means. Instant, browser-side.
Open guideline tool →For licensed clinicians. Not a substitute for clinical judgement.
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