Some info here
I would have said there's less eccentric loading on the PF joint during forefoot running, assuming stride length is shorter. However if stride length's ahead of centre of gravity this will not be the case.
There's different types of forefoot running - in the POSE style there's little effort from the quads and therefore the PF tendon; the emphasis is on the hamstrings to pull the foot from the ground from an optimal landing position with fast cadence.
What's the patient's hip flexion like - have you tested for psoas / rec fem tightness?