Skip to content
head and shoulder muscles

Preedy v RTWSA: When Should Multiple WPI Assessments be Combined?

6 minutes read time

Preedy v Return to Work Corporation SA [2019] SAET 228. This significant decision seeks to apply the Supreme Court findings regarding the combination of whole person impairment assessments pursuant to ss 22(8)(c) and 58(6)(a) RTWA.

On 19 November 2019 a significant decision was delivered by the South Australian Employment Tribunal (SAET), after the matter was remitted from the Full Court of the Supreme Court. This important decision outlines when it is appropriate to combine multiple workplace injuries.

The decision also highlights inconsistencies between section 22(8)(c) of the Return to Work Act 2014 (SA) (RTWA) and paragraph 1.19 of the Impairment Assessment Guidelines (IAG), and recommends that they be considered by Parliament.

Key Facts of Preedy v Return to Work Corporation SA

Mr Preedy injured his left shoulder during his employment in 2012. Whilst receiving physiotherapy treatment for the shoulder injury, he sustained a fracture to the left side of his neck (the C5 vertebrae). Mr Preedy was suffering from multiple myeloma, a form of cancer which weakened his C5 vertebrae of his neck. It was found by Dr Porteus that the neck injury was caused by Mr Preedy’s underlying myeloma, and even without physiotherapy, it was likely to eventually fracture.

Mr Preedy received lump sum compensation for non-economic loss for his left shoulder injury based upon an 11% whole person impairment (WPI).

Pursuant to the RTWA, Mr Preedy was found to have a 27% WPI from the neck injury.

Mr Preedy argued that the two assessments should be combined per ss 58(6)(a) and 22(8)(c) of the RTWA so as to meet the 30% WPI threshold for a seriously injured worker.

The matter was first heard by Deputy President Judge Calligeros which was then appealed to the Full Bench of SAET and then to the Full Court of the Supreme Court. The Full Court remitted the matter back to the SAET to determine the matter in accordance with the direction of the Full Court that combination could occur under either ss 22(8)(c) or 58(6)(a) of the RTWA.

What were the Key Issues?

The following key issues were considered by Deputy President Judge Calligeros:

  1. Are the WPI’s from the same injury or cause under s 22(8)(c) RTWA?
  2. Do the WPI’s from the left shoulder and neck injuries arise from the same trauma under s 58(6) RTWA?

Key Legislative Provisions

Impairments from “the same injury or cause” are to be assessed together or combined to determine the degree of impairment (using any principle set out in the Impairment Assessment Guidelines).

If a worker suffers 2 or more work injuries arising from the same trauma –

a)      The injuries may together be treated as 1 injury to the extent set out in the Impairment Assessment Guidelines (and assessed together using any combination or other principle set out in the Impairment Assessment Guidelines).

Impairments resulting from more than one injury “caused by the same trauma” are to be assessed together and combined to arrive at the degree of permanent impairment of the worker (refer to subsection 22(8)(c) of the Act).

Same Trauma?

Deputy President Judge Calligeros stated that the shoulder injury was sustained by Mr Preedy when he was loading a heavy toolbox into his vehicle, whereas the neck injury did not result from this trauma, but the later physiotherapy. It was found that the two injuries arose from different traumas at different times.

Deputy President Judge Calligeros described the traumas as successive traumas rather than “the same trauma” and therefore the assessments should not be combined under s 58(6)(a) RTWA.

This finding followed the decision of Marrone[1] where it was found that a later left arm injury that was said to arise because of an earlier right shoulder injury was not caused by the same trauma.

Same Injury or Cause?

The second issue for consideration was whether the two injuries arose from the same injury or cause pursuant to s 22(8)(c) RTWA.

Judge Calligeros decided that the neck impairment and left shoulder impairment did not arise from the same injury, as similarly to there being two separate traumas at different times, there were also two separate injuries which resulted in the impairments.

A detailed analysis of the word ‘cause’ was undertaken by Deputy President Judge Calligeros who concluded that the word ‘cause’ under s 22(8)(c) RTWA did not need to be the only cause or the predominant cause, to contribute to the injury to a sufficient extent.

Deputy President Judge Calligeros noted that there is a distinction between causation in the medical sense and the legal sense, which does not require the same degree of certainty.

Therefore, at law, adverse results of treatment for a work injury form part of that work injury for the purposes of causation. Accordingly, Mr Preedy’s neck impairment was from the same cause as the injury to the left shoulder.

As the impairments were from the same cause but not from the same injury. S 22(8)(c) RTWA was satisfied.

Inconsistency argument

A further argument was put that paragraph 1.19 of the IAG displaced the operation of s 22(8)(c) and therefore the assessments could only be combined if the impairments were caused by the same trauma. However, Deputy President Judge Calligeros stated that:

…well established statutory interpretation principles directs that s 22(8)(c) as a statutory provision takes precedent over para. 1.19.

This meant that any inconsistency between s 22(8)(c) RTWA and paragraph 1.19 IAG should be resolved in favour of s 22(8)(c).


Deputy President Judge Calligeros concluded that the subsequent neck injury was “caused by” the left shoulder injury and should therefore be combined pursuant to s 22(8)(c) RTWA.

He further considered possible drafting errors in s 22(8)(c) or paragraph 1.19 IAG as they ‘do not sit comfortably together’.[2] Parliamentary consideration was therefore suggested.

Significant Implications

The outcome of the decision is significant as it finds that the concept of “cause” of an injury is a broad concept that allows for the combining of injuries for determining WPI even though they do not arise from the same injury or the same trauma.

The decision is subject to an appeal to the Full Bench of the Tribunal and there are other matters on appeal with the same issue so there is no definitive interpretation as yet.

There is good reason to question the interpretation and /or drafting of the RTW Act because if “cause” has an expansive definition then why the limiting terms of injury and trauma in the RTW Act and IAG.

Contact Us

If you have any questions regarding this alert, please contact Guy Biddle.

[1] Marrone v Employers Mutual Limited as an agent for WorkCover Corporation of South Australia [2013] SASCFC 67.
[2] Preedy v Return to Work Corporation of South Australia [2019] SAET 228, 88.

This Alert is intended as general information only. It does not purport to be comprehensive advice or legal advice. Readers must seek professional advice before acting in relation to these matters.

Download this Legal Alert: Preedy v RTWSA: When Should Multiple WPI Assessments be Combined?