That incomplete assessment had dramatic consequences for the man, who was almost 90 years old at the time of the incident, his daughter, identified as Mrs C, said.
Prior to the incident the man had been able to do 50 sit-ups and press-ups each morning, and look after himself in his own home, Mrs C told Allan.
"He worked on his van each day, which he built. He would walk down the hill and back up every other day to get groceries," she said.
"He is now a man in need of constant care."
Mr A earlier rang for help in October 2019 after spending a few hours working under his van.
Following a clinical assessment on the phone, a paramedic and an emergency medical technician (EMT) attended the man.
The paramedic and the EMT assessed his leg but didn't remove his sock, deputy commissioner Allan said.
"They considered his pain was musculoskeletal and decided not to transfer him to hospital," he said.
The deputy commissioner was not only critical of the paramedic's assessment of the man, but also said the paramedic's "documentation fell below accepted standards and did not adhere to the ambulance service's guidelines".
Allan accepted the EMT was not the most senior clinician responsible for the man's care.
However, he was critical of the "lack of reflection and responsibility shown by the EMT".
Allan said there was a greater need for effective communication, collaborative working, and collective ownership of the challenges in treating Mr A.
He reminded the ambulance service of the importance of having strategies in place to promote these aspects in its organisation.
The paramedic had since retired and provided the man with a written apology.
Allan recommended that if the paramedic returned to practice, he should arrange for further training.
He also recommended the ambulance service report to the HDC on the outcome of the EMT's competency review and subsequent training.
It should also provide the HDC with evidence of staff training on conflict and communication breakdowns.
