Polwarth had his right leg amputated below the knee, following a motorcycle accident when he was 20, the court heard.
However, with the use of a prosthetic leg, he was able to function quite normally, including playing 18 holes of golf three times each week, in which he walked about five kilometres.
On February 20, 2014, he entered the Hervey Bay Woolworths store, where he slipped on a grape on the floor with his left leg, causing him to fall directly onto the stump of his right knee, reinjuring it.
Woolworths did not deny its culpability in causing the fall but disputed the level to which Polwarth said it had left him disabled.
Polwarth claimed after the incident he was rendered unable to do the things he had previously done for himself, including showering and drying himself, housework, grocery shopping, preparing meals of mowing the lawns.
He also said his ability to drive himself around was severely limited in the wake of the incident.
He claimed he was almost wholly dependent on his partner, Tammy Stephens, to do those things for him.
Polwarth sought just more than $40,000 for past care, and more than $100,000 for projected future care assistance.
However, unbeknown to the pensioner, Woolworths undertook camera surveillance outside his home on two separate occasions two years after the incident, in March and October, 2016.
It showed him walking, standing and driving for extended periods of time, which contradicted the evidence he gave the court.
Judge David Searles found "the surveillance footage speaks for itself".
"The level of functioning of the Plaintiff is self-evidence and reflects that his ability to function has not been significantly curtailed," the judge said.
Polwarth had also claimed the fall had left him unable to wear his prosthetic leg for long periods of time, another claim the surveillance footage disproved.
Searles awarded Polwarth a combined $11,111 for the injury, including $4080 in general damages, a further $4687 for the arthroscopy of his knee and nearly $2300 for travel, Medicare, pharmacy and lawn mowing costs in the immediate wake of the incident.
He found no basis for awarding damages for ongoing care.