What happened: NRMA Insurance's challenge to an 11% whole person impairment rating was dismissed on all three grounds by the NSW Supreme Court
Who's involved: NRMA Insurance (CTP insurer), the Personal Injury Commission of NSW
What's at stake: The claimant's entitlement to non-economic loss damages, hinging on whether the rating sat above or below the 10% threshold
Why it matters: Medical assessors have broad discretion in choosing impairment methodology when standard testing cannot be relied on
Where it stands: Dismissed on all grounds; NRMA ordered to pay costs
The whole case turned on six percentage points - three for each shoulder.
A motorist was rear-ended in October 2021 by a vehicle fitted with a bull bar. He suffered a fracture to part of a neck vertebra, injured both shoulders, and lodged a claim for common law damages under New South Wales' Motor Accident Injuries Act. To access those damages, he needed a whole person impairment (WPI) rating above 10%.
The medical assessor put him at 11%. NRMA Insurance, the compulsory third-party insurer on the at-fault vehicle, took the fight to the NSW Supreme Court with three grounds of challenge. All three were dismissed.
The dispute centred on how the assessor rated the shoulders. During the clinical examination, the assessor used a measuring device called a goniometer three times to test shoulder movement. He observed the claimant tensing up during testing - known in clinical terms as voluntary guarding - and concluded the movement measurements were unreliable.
So he looked elsewhere. MRI scans of both shoulders showed arthritis and swelling in the joint where the collarbone meets the shoulder. The assessor turned to two reference tables from the AMA Guides - the standard manual for rating permanent impairment - and translated those MRI findings into a 3% WPI rating for each shoulder.
NRMA's argument was direct: one of those tables, Table 20, states on its face that it applies "only when there is full range of motion of the joint." The insurer pointed out that the assessor's own examination had recorded reduced motion in both shoulders. The table should not have been used, NRMA argued.
The court disagreed. Under the Motor Accident Guidelines, when movement measurements are unreliable, the assessor has discretion to weigh "other available evidence" to determine whether an impairment exists. The court found the assessor's decision to use the AMA reference tables fell within that discretion. Nothing in the Guidelines ruled it out, and the approach was not so unreasonable that it warranted being overturned - the benchmark the court applied for disturbing a medical assessor's chosen method.
NRMA's second ground was more targeted. The insurer had flagged the shoulder methodology as a specific error in its written submissions to the review panel. The panel's reasons addressed the insurer's causation arguments in detail but said nothing about the shoulder methodology complaint.
The court accepted the panel had "overlooked" that argument. That was an error. But not every oversight invalidates a decision - the question was whether there was a "realistic possibility" the outcome could have been different.
NRMA could not show one. The insurer had not pointed to any alternative method the assessor should have used, or what a different approach would have produced. Without that, the court found the argument on impact did "not rise above speculation."
The third ground challenged the review panel's decision not to physically re-examine the claimant. NRMA argued the unresolved shoulder methodology dispute made a fresh examination essential.
But the court pointed to what NRMA had actually submitted to the panel on that question: the insurer's own written case for re-examination had focused on causation - whether the collision was forceful enough to cause the injuries claimed - not on shoulder assessment methodology. The panel had addressed those submissions. A decision-maker does not err by failing to deal with arguments that were never put to it.
Three grounds. Three dismissals. NRMA was ordered to pay costs.
The decision is a pointed reminder for CTP claims teams: once a medical assessor exercises discretion under the Motor Accident Guidelines, the path to overturning that choice on judicial review is narrow - and the court will not fill the gaps in an insurer's alternative case.
