📏 Lower-Limb Alignment (HKA / MAD / mLDFA / MPTA / JLCA)
UseKnee & lower-limb alignment imaging: lateral knee, axial CT/MRI and standing long-leg films — patellar instab…
SourcePaley D. Principles of Deformity Correction. Springer 2002
This-shift next steps
After scoring: open the scene pack, peer scores, and the matching pathway. Local reference — no HIS write.
Paste the link in Slack, Teams, X, or LinkedIn — the preview image comes from this page’s Open Graph card.
Methodology · worked example, guidelines & full notes
Standing bilateral long-leg AP (patellae forward).
When to use
Knee & lower-limb alignment imaging: lateral knee, axial CT/MRI and standing long-leg films — patellar instability and osteotomy / arthroplasty planning.
How it works
HKA deviation from 180° ≤ 3°: neutral alignment HKA deviation from 180° 3–10°: mild–moderate malalignment HKA deviation from 180° ≥ 10°: marked malalignment MAD (medial positive) < 1 mm (lateral): valgus MAD (medial positive) 1–15 mm medial: normal (8 ± 7 mm) MAD (medial positive) > 15 mm medial: varus mLDFA < 85°: distal femoral valgus mLDFA 85–90°: normal (87 ± 3°) mLDFA > 90°: distal femoral varus MPTA < 85°: proximal tibial varus (typical HTO indication) MPTA 85–90°: normal (87 ± 3°) MPTA > 90°: proximal tibial valgus JLCA 0–2°: normal JLCA > 2°: intra-articular contribution (cartilage loss / laxity)
Key points
- Standing bilateral long-leg AP (patellae forward).
- 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.
References
- Paley D. Principles of Deformity Correction. Springer 2002
- Paley D, et al. Deformity planning for frontal and sagittal plane corrective osteotomies. Orthop Clin North Am 1994;25:425-465
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.
| Alignment direction | Valgus |
|---|---|
| HKA deviation from 180° | 6 ° |
| MAD (medial positive) | 20 mm |
| mLDFA | 88 ° |
| MPTA | 84 ° |
| JLCA | 3 ° |
→HKA deviation from 180°6°
- HKA deviation from 180°：6 ° → 3–10°: mild–moderate malalignment
- MAD (medial positive)：20 mm → > 15 mm medial: varus
- mLDFA：88 ° → 85–90°: normal (87 ± 3°)
Verification & sources · governance
FAQ
Frequently asked questions
- What are the limits and cautions when using Lower-Limb Alignment (HKA / MAD / mLDFA / MPTA / JLCA)?
- 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 Lower-Limb Alignment (HKA / MAD / mLDFA / MPTA / JLCA) 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 Lower-Limb Alignment (HKA / MAD / mLDFA / MPTA / JLCA) calculated in practice? Can you show a worked example?
- Inputs: Alignment direction Valgus, HKA deviation from 180° 6 °, MAD (medial positive) 20 mm, mLDFA 88 °, MPTA 84 °, JLCA 3 ° → Result: HKA deviation from 180° 6 °（HKA deviation from 180°: 6 ° → 3–10°: mild–moderate malalignment, MAD (medial positive): 20 mm → > 15 mm medial: varus, mLDFA: 88 ° → 85–90°: normal (87 ± 3°)）