Since the patient "fell," this would be a Traumatic Fracture, i.e. requiring an S Code from the S52.5 _ _ _ +/- S52.6 _ _ _ Code Sets, depending on the extent/severity of the fracture. The fact that the patient has Osteoporosis is not relevant to the fact that she fell. If she has "documented" Osteoporosis, it could be listed as a complementary/supplemental code from the M81 Code Set, which is the Code Set for the Disease of Osteoporosis. External Cause Codes may or may not be required by her insurance/payer.
I refer you to icd10orthocoder.com where you can review the Blog on Fractures of the Forearm and Wrist, and External Cause Coding if required.
Respectfully submitted, Alan Pechacek, M.D.
icd10orthocoder.com