In the latest finding from the HDC, the woman, who is in her 70s, was not able to get in or out of bed on her own.
Wall said it was most likely a staff member was with her when she received her injuries, but the rest home was unable to establish what happened.
No staff member was able say what happened.
An ambulance was called five hours after she was discovered to have multiple fractures to her shoulder and legs, and she died days later.
"The woman concerned was particularly vulnerable and she relied heavily on Radius Elloughton Gardens to provide her with an appropriate standard of care and keep her safe," Wall said.
"Significant systems issues were present at the rest home, which in my opinion compromised the quality of the care provided to her.
"Staff failed to adhere to Radius's policies, there was a delay in getting the woman to hospital, a pattern of poor documentation by its staff members, and the training provided to its nursing staff was inadequate.
"This report highlights the importance of having a culture that encourages staff to speak up, ensuring that staff follow policy, and of clear and accurate documentation."
The rest home has been told to undertake a review of all current staff training records; conduct random audits of staff compliance with its policies; and provide the woman's family with an apology.
They have also been recommended to provide an update on an external recommendation that CCTV be installed.
Wall has also referred Radius Residential Care Limited to the Director of Proceedings.
The rest home said it had apologised to the family for what happened in 2018.
It has since worked with the South Canterbury District Health Board to improve training for nurses and provide better care.
