Final answer:
Genu recurvatum, knee flexion contracture, patella baja, and patella alta occur in the sagittal plane.
Step-by-step explanation:
The correct plane in which genu recurvatum, knee flexion contracture, patella baja, and patella alta occur is the sagittal plane. The sagittal plane divides the body into left and right halves. These conditions all involve abnormal positions or movements of the knee joint, which are best viewed from a side-on perspective, making the sagittal plane the appropriate plane to assess them.