Perhaps an 90 degrees adolescent blade plate is a better option with less risk of an AVN? The DHS is a big thing for this little head. Biomechanically the blade plate is in theory better than the DHS for this fracture.

Rene Hartel
CH Argentan
France

This complication usually happen when the registrar or the resident made multiple holes by the K.wire in the lat. cortex trying to localize the center of the neck.
The problem of these fractures it extends above the lesser trochanter , If you can put DHS this will be excellent but the entry of the DHS will be below  or at the fracture site and this is difficult to hold the fracture very well.
I would suggest to leave the screw in place and put Buttress T-plate after reduction of the fracture with 3 screws above the fracture and 4-5 below ,followed by NWB  for 6 weeks.
The risk of AVN is possible.
I Did find in my collections one similar case of yours.

Best Luck.
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Dr.Freih  Odeh  Abu Hassan,
M.D.(Orth.) ,F.R.C.S.(Eng.) ,F.R.C.S.(Tr.&Orth.).
Asst.Prof. of Orthopedics & Pediatric Orthopedics Surgery,
University of Jordan - Amman.