I think the plate is too short. It would be better to use a longer plate, with the same number of screws. It would give a more stable fixation for this fracture.

I agree that a longer plate is required. Moreover the distal screws seem to be thinner for the plate holes.

Add autologous bone graft. In some cases you can use double plating, with a medial plate to add stability.

Sure

Infection ruled out? Also the the distal screw in the proximal part seems to be too close to the fracture site.

There was no evidence of infection. The screws in the distal end of plate were thinner than required and hence there was failure of fixation