CPAK Classification (Knee Alignment Phenotype)
Classifies a knee into one of the nine CPAK phenotypes from the medial proximal tibial and lateral distal femoral angles.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Medial proximal tibial angle
- 86 degrees
- Lateral distal femoral angle
- 89 degrees
Result: CPAK type I: varus arithmetic HKA (-3 deg) and apex distal joint line (JLO 175 deg).
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Medial proximal tibial angle (MPTA)
- Lateral distal femoral angle (LDFA)
How this is calculated
Citation
MacDessi SJ, Griffiths-Jones W, Harris IA, Bellemans J, Chen DB. Coronal Plane Alignment of the Knee (CPAK) classification: a new system for describing knee phenotypes. Bone Joint J. 2021;103-B(2):329-337. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.