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Hip Stability
- Determine YZ joint center positions of the respective limb’s Ankle, Knee, and Hip
- Calculate the respective differences in Y and Z between the Knee and Hip joint centers, and Ankle and Knee joint centers.
- Calculate segment angles for the thigh and shank segments by taking the inverse tangent of the Z difference over difference in Y.
- Calculate the Knee valgus angle by subtracting the thigh segment angle from the shank segment angle.
- If Knee valgus angle is greater than -5, score is 2.
- If Knee valgus angle is less than -10, score is 0.
- Otherwise score is 1.