Motor Vehicle Accident Injury Causation: When is a Subsequent Femur Fracture and Knee Injury Attributable to a Car Accident for Threshold Injury Determination?

Introduction
Based on the authentic Australian judicial case Imer v Insurance Australia Limited t/as NRMA Insurance [2025] NSWPICMP 24, this article disassembles the Court’s judgment process regarding evidence and law. It transforms complex judicial reasoning into clear, understandable key point analyses, helping readers identify the core of the dispute, understand the judgment logic, make more rational litigation choices, and providing case resources for practical research to readers of all backgrounds.

Chapter 1: Case Overview and Core Disputes

Basic Information:

Court of Hearing: Personal Injury Commission, Medical Review Panel
Presiding Judge: Member Susan McTegg (Panel Member), Senior Medical Assessor Ian Cameron (Panel Medical Assessor), Medical Assessor Margaret Gibson (Panel Medical Assessor)
Cause of Action: Dispute regarding “threshold injury” classification and causation under the Motor Accident Injuries Act 2017.
Judgment Date: 10 January 2025
Core Keywords:
Keyword 1: Authentic Judgment Case
Keyword 2: Threshold Injury
Keyword 3: Causation
Keyword 4: Femur Fracture
Keyword 5: Knee Injury
Keyword 6: Motor Accident Injuries Act 2017

Background:

On 1 April 2022, the Claimant, Ms Gaetana Imer, was involved in a motor vehicle accident while driving her vehicle. The collision caused her to sustain injuries. Approximately 30 hours after the accident, on 2 April 2022, Ms Imer experienced a sudden fall in her home, resulting in a fractured left femur and subsequently, a diagnosis of osteoporosis. The Insurer, Insurance Australia Limited trading as NRMA Insurance, determined that Ms Imer’s injuries were threshold injuries, limiting her statutory benefits. The Claimant sought a review of this determination, alleging that her femur and knee injuries were caused by the motor vehicle accident, thus falling outside the definition of a threshold injury.

Core Disputes and Claims:

The central dispute revolved around the causation of specific injuries sustained by the Claimant following the motor vehicle accident:
1. Left Femur Fracture: The Claimant asserted that the motor vehicle accident either directly caused the femur fracture or caused instability in her leg, leading to the subsequent fall and fracture. The Insurer contended that the fracture was caused by the fall at home, unrelated to the accident.
2. Right and Left Knee Injuries: The Claimant alleged that the accident caused or contributed to the worsening of injuries to both knees. The Insurer argued these were pre-existing conditions or not causally linked to the accident.
The determination of whether these injuries were causally linked to the accident was critical, as it would define whether they constituted “threshold injuries” under the Motor Accident Injuries Act 2017, impacting the duration of statutory benefits payable.

Chapter 2: Origin of the Case

The narrative of this litigation began on 1 April 2022 when the Claimant, Ms Gaetana Imer, was driving her vehicle. Her adult child was a passenger. Ms Imer described seeing another vehicle approaching an intersection that was likely to collide with her. She accelerated, but the other vehicle impacted the rear of the driver’s side of her car, causing her vehicle to “fishtail” before she brought it to a halt. In the impact, she asserted that her left leg hit the centre console. The other driver then absconded without exchanging details.

Following the accident, Ms Imer stated she remained in her vehicle at her adult child’s home for about an hour, discussing the incident and recovering emotionally. She then drove home and, despite some difficulty, walked up the steps into her house. She reported developing neck and right shoulder pain within hours of the accident.

The following day, 2 April 2022, Ms Imer attended a general practitioner’s (GP) office due to persistent neck and shoulder pain. She informed the GP of her multiple pains, including in her knees, but crucially, stated she did not have left thigh pain at this time. Later that same day, she drove herself to Merrylands Police Station, using her wheeled walking frame for assistance, to report the hit-and-run incident. After making the report, she returned home.

In the late evening of 2 April 2022, Ms Imer recounted that as she was walking down the hallway of her home, she suddenly felt a “crack” and fell to the floor, unable to get up. She called an ambulance and was subsequently taken to Westmead Hospital in the early hours of 3 April 2022. Imaging revealed a comminuted fracture of her distal left femur. During her hospital admission, a fracture of the distal right femur was also discovered and managed conservatively. She was later diagnosed with osteoporosis and hypercalcaemia, leading to surgery on her parathyroid gland.

On 15 July 2022, the Insurer determined that Ms Imer’s injuries were “threshold injuries” under the Motor Accident Injuries Act 2017, denying statutory benefits beyond 26 weeks. Ms Imer sought an internal review, which affirmed the Insurer’s determination on 12 August 2022. Dissatisfied, Ms Imer filed an application with the Personal Injury Commission, initiating the legal dispute over the causation and classification of her injuries.

Chapter 3: Key Evidence and Core Disputes

Claimant’s Main Evidence and Arguments:

• Application for Personal Injury Benefits (18 April 2022): Listed injuries including “broken femur left leg,” “serious bruising of right knee fracture,” “whiplash neck pain,” and “right shoulder pain,” asserting these were a result of the accident and hospitalisation.
• X-ray Left Knee (25 February 2022): Performed less than two months before the accident, this imaging showed “no fracture” of the left knee, supporting the argument that any subsequent fracture or significant injury was post-accident.
• Claimant’s Account during Medical Assessment: Stated she hit her left leg on the centre console during the accident and that her “femur gave out” before she collapsed at home, directly linking the fall to an accident-related instability. She disputed the ambulance report’s assertion that she “tripped.”
• Argument on Causation: Submitted that the accident caused instability in her lower limbs, leading to her fall and subsequent fractures. Emphasised the short time lapse between the accident and her hospitalisation. Argued that Medical Assessor Home failed to adequately explain the conclusion that the accident mechanism could not cause the alleged lower limb injuries.

Respondent’s Main Evidence and Arguments:

• Police Report (2 April 2022): Reported damage to the rear offside of the Claimant’s vehicle; noted no emergency services were called and the Claimant’s vehicle was still driveable.
• Photographs: Showed damage to the driver’s side rear panel of the Claimant’s vehicle, indicating a low-impact collision.
• Catherine Imer’s Statement (12 August 2022): The Claimant’s adult child, a passenger, stated the impact was a “quick jolt type” and that airbags did not deploy. She was “not sure if mum complained of any immediate injury” and that the vehicle damage “was not major and the car was still driveable.”
• Dr Andrew McIntosh, Biomechanical Engineer Report (23 August 2022): Concluded it was “highly unlikely” the Claimant suffered any femur injury during the accident due to low forces, no intrusion into the seated area, no contemporaneous superficial injuries, minor overall movement, and no plausible mechanism for femur fractures in a side impact without intrusion.
• Dr Milinkic, GP Records (2 April 2022): Consultation following the accident noted “neck pain, shoulders pain, right elbow, wrist and hand pain, upper back, lower back, knees pain, headache and dizziness,” but notably “no left thigh pain.”
• Ambulance Report (2 April 2022): Recorded Ms Imer stating she “tripped and fell onto carpet on both knees,” contradicting her later assertion that her “femur gave out.”
• Westmead Hospital Discharge Summary (27 May 2022): Stated Ms Imer “presented… with left femur fracture following a fall.” Also recorded diagnosis of osteoporosis and hypercalcaemia.
• Monica North, Occupational Therapist Report (13 July 2022): Reported Ms Imer “did not experience any leg pain immediately after the accident” and was able to self-extricate and attend the police station.
• X-rays/CT Scans (3 April 2022 & 19 April 2022, 2 August 2022): While initial X-rays (3 April 2022) suggested a possible acute fracture in the right knee, subsequent CT (19 April 2022) and later X-ray (2 August 2022) explicitly stated “No acute injury identified” and “No acute fracture is identified” for the knees. Confirmed comminuted distal femoral fracture(s).
• Argument on Causation: Maintained that the bilateral femur fractures were caused by the fall at home, unrelated to the accident, and that the knees had pre-existing osteoarthritis, with no evidence of acute fracture caused by the accident. Cited lack of contemporaneous leg pain immediately post-accident.

Core Dispute Points:

1. Causation of Left Femur Fracture: Was the left femur fracture a direct result of the motor accident or caused by a subsequent, unrelated fall at home?
2. Causation of Right and Left Knee Fractures: Were the alleged right and left knee fractures actually sustained in the accident, or were they pre-existing conditions not aggravated by the accident?
3. Nature of Injuries: Did any injuries (cervical spine, shoulders, knees) qualify as “non-threshold injuries” under the MAI Act 2017 due to causation by the accident?

Chapter 4: Statements in Reports

In this case, the parties primarily presented their factual and evidentiary positions through various medical reports, police reports, and statements to investigators, rather than formal affidavits. The Review Panel meticulously examined these documents, highlighting inconsistencies and strategic intentions.

The Claimant, Ms Gaetana Imer, provided her version of events to her treating GP, Dr Milinkic, the ambulance service, Westmead Hospital, and occupational therapist Monica North, as well as to Medical Assessors Cameron and Gibson. A notable development in her account was her assertion during the Review Panel assessment that she struck her left leg on the centre console during the accident. This detail was not consistently recorded in her early medical notes or her initial statement to an investigator, which merely noted, “I might have hit my left leg but I was able to walk away from the accident.” This evolving narrative raised questions for the Panel regarding the immediate impact and severity of any leg injury at the time of the collision.

Crucially, Ms Imer also maintained that her “femur gave out” in the hallway of her home, leading to her fall and the subsequent fracture. However, this contradicted the Ambulance Report, which explicitly stated she “tripped and fell onto carpet on both knees.” This discrepancy—between a spontaneous collapse due to a weakened leg versus an accidental trip—was a significant point of contention. The Panel noted the strategic intent behind Ms Imer’s attempt to reframe the cause of the fall, aiming to establish a causal link to the accident for the femur fracture.

The Insurer, on the other hand, strategically relied on the contemporaneous records, which consistently lacked immediate complaints of left thigh pain post-accident. The GP’s notes from the day after the accident listed various pains but no mention of left thigh issues. Similarly, the occupational therapist’s report explicitly stated Ms Imer “did not experience any leg pain immediately after the accident.” These records served the Insurer’s strategic intent to demonstrate a lack of direct injury to the femur or knees from the accident itself. The biomechanical report further buttressed the Insurer’s position by scientifically disputing the possibility of a femoral fracture from the low-impact collision.

The Panel’s procedural directions regarding the affidavits (or in this case, statements and reports) aimed to focus the parties on the core causation issue. By requiring parties to confirm agreement on non-disputed body parts (cervical spine, shoulders), the Panel streamlined the review process, concentrating resources on the contentious lower limb injuries. The careful comparison of these different expressions of the same events allowed the Panel to scrutinise the reliability and consistency of the factual matrix, which was pivotal in revealing the boundary between assertion and demonstrable fact.

Chapter 5: Court Orders

Prior to the final determination, the Review Panel issued specific procedural directions to manage the review efficiently. These were crucial in narrowing the scope of the dispute and preparing for the final assessment.

1. Document Bundles: The Review Panel directed both parties to file indexed and paginated bundles of documents by specified dates to ensure all relevant evidence was systematically presented for review.
2. Scope of Assessment Agreement: Following the initial Medical Assessor’s findings on the cervical spine, right shoulder, and left shoulder, the Review Panel sought and obtained the parties’ agreement that these body parts did not need re-assessment. The Panel confirmed it would rely on Medical Assessor Home’s original findings for these injuries. This streamlined the review, focusing efforts on the remaining disputed injuries.
3. Mode of Assessment for Disputed Injuries: The Panel proposed that the medical assessment for the central issue—the causation of injuries to the left and right knees and left thigh—be conducted with the Claimant attending by audio-visual link with the Medical Assessors of the Panel. The Panel explicitly stated it considered a physical examination of the knees or left thigh unnecessary for this specific determination. This approach was agreed upon by both parties, further shaping the procedural arrangements for the review.

Chapter 6: Hearing Scene: Ultimate Showdown of Evidence and Logic

The hearing before the Review Panel, conducted by videoconference, served as the ultimate arena where the Claimant’s assertions regarding the causation of her lower limb injuries faced the rigorous scrutiny of contemporaneous medical records, expert biomechanical analysis, and the Panel’s collective medical and legal expertise.

The Claimant, Ms Imer, presented a compelling personal account, stating that she hit her left leg on the centre console during the accident and that, approximately 30 hours later, her femur “gave out” leading to her fall and subsequent fractures. This narrative sought to establish a direct causal link, suggesting that the accident either caused an immediate, albeit subtle, injury that led to the later collapse, or that the accident weakened the limb to such an extent that it spontaneously fractured.

However, this narrative was confronted by a formidable array of objective evidence. The Panel meticulously highlighted the logical inconsistencies in the Claimant’s account when weighed against contemporaneous records:

• Plausibility of Mobility: The Claimant’s ability to drive home, sit for an hour at her adult child’s house, climb stairs, attend a GP consultation, and even drive to and report the incident at a police station—all occurring for over 24 hours after the accident but before the fall—was critically examined. The Medical Assessors, drawing on their clinical experience, found it highly implausible that a person could mobilise on a displaced femoral shaft fracture. The Panel stated:
  

  “The Panel finds that being able to mobilise for well over 24 hours without significant left thigh or femoral pain is not consistent with the femoral fracture sustained by Ms Imer occurring at the time of the accident.”
  This statement was immediately followed by the decisive conclusion:
  “Indeed, the Panel finds it would not be plausible to conclude that Ms Imer was able to walk on a displaced fracture of the femoral shaft.”
  This underscored the fundamental medical implausibility of the Claimant’s timeline if the fracture had occurred in the accident.

• Absence of Contemporaneous Complaints: The GP’s notes from the day after the accident, listing various sites of pain, explicitly omitted any mention of left thigh pain. Furthermore, Monica North, the occupational therapist, reported being informed that Ms Imer “did not experience any leg pain immediately after the accident.” The absence of these critical contemporaneous complaints significantly undermined the Claimant’s later assertion of an immediate leg injury from the collision. The Panel also found it implausible that the GP would have missed such a significant injury.

• Discrepancy in Fall Mechanism: The Ambulance Report, a contemporaneous record, stated Ms Imer “tripped and fell onto carpet on both knees.” This directly contradicted Ms Imer’s claim that her femur “gave out” spontaneously. The Panel considered this discrepancy crucial, indicating that the fall was an event separate from any accident-related instability.

• Biomechanical Evidence: The report of Dr Andrew McIntosh, a biomechanical engineer, provided compelling objective evidence. He opined that the low-impact nature of the accident (rear driver’s side panel damage, no intrusion, minor occupant movement, restrained by seatbelt) meant that the forces applied to the lower limbs were insufficient to cause a femoral fracture. While not conclusive in itself, this expert opinion persuaded the Panel that the mechanism of the accident could not have caused the alleged fractures. The Panel held:

  “The Panel has also considered the opinion of Dr McIntosh as to the mechanics of the accident. Whilst the opinion of Dr McIntosh is not conclusive the Panel accepts there were insufficient forces applied to the lower limbs meaning it is unlikely the claimant could have sustained a femoral fracture in the accident.”
  This highlighted the Panel’s reliance on expert scientific analysis to assess the physical possibilities of injury causation.

The collective weight of these objective inconsistencies and expert opinions led the Panel to conclude that the Claimant’s femur fracture was not causally linked to the motor accident. The factual matrix, particularly the Claimant’s post-accident mobility and the absence of immediate complaints, coupled with the biomechanical evidence, logically drove the decision, outweighing the Claimant’s later recollections.

Chapter 7: Final Judgment of the Court

The Review Panel, after conducting a new assessment of the medical dispute, affirmed the certificate of Medical Assessor Alan Home dated 17 February 2023.

The Panel made the following final determinations regarding the Claimant’s injuries:

Injuries Caused by the Accident and Classified as Threshold Injuries:
* Cervical spine: aggravation of pre-existing cervical spondylosis.
* Right shoulder: aggravation of pre-existing right shoulder osteoarthritis.
* Left shoulder: soft tissue injury; aggravation of pre-existing left shoulder osteoarthritis.

Injuries Not Caused by the Accident:
* Left thigh femur fracture.
* Left knee fracture.
* Right knee fracture.

Therefore, the Review Panel’s decision explicitly confirmed that the Claimant’s femur fracture and both knee fractures were not causally related to the motor vehicle accident on 1 April 2022.

Chapter 8: In-depth Analysis of the Judgment: How Law and Evidence Lay the Foundation for Victory

The Review Panel’s judgment in Imer v Insurance Australia Limited t/as NRMA Insurance [2025] NSWPICMP 24 provides a detailed examination of causation in the context of threshold injuries under the Motor Accident Injuries Act 2017. The Panel’s meticulous approach to weighing evidence, particularly contemporaneous records against later recollections and expert opinions, laid a clear foundation for its conclusions.

Special Analysis:
This case underscores the critical importance of contemporaneous medical records and expert biomechanical evidence in disproving causation claims, even when a claimant presents a compelling personal narrative. The Panel effectively navigated the tension between a claimant’s subjective experience and objective evidence, demonstrating how inconsistencies in reporting, coupled with scientific analysis, can decisively shape the outcome of a causation dispute. The decision highlighted that while the absence of immediate complaint is not determinative, it carries significant weight when corroborated by other objective facts and expert opinion.

Judgment Points:
1. Plausibility of Mobility on Fracture: The Panel found it medically implausible for the Claimant to have sustained a displaced femoral fracture in the accident and then be able to mobilise for over 24 hours without significant pain before her fall. This finding was pivotal in severing the causal chain between the accident and the femur fracture.
2. GP’s Failure to Identify Fracture: The Panel deemed it implausible that a GP attending the Claimant the day after the accident would have failed to identify a significant left femur fracture, further distancing the fracture from the accident date.
3. Discrepancy in Fall Mechanism: The direct contradiction between the Claimant’s assertion that her leg “gave out” and the ambulance report stating she “tripped” was a crucial factual finding. The Panel accepted the contemporaneous ambulance report, thereby attributing the fall to an accidental trip rather than an accident-induced instability.
4. Lack of Contemporaneous Leg Pain: The absence of any documented complaint of left thigh or knee pain immediately after the accident, or in the GP notes the following day, significantly undermined the Claimant’s later claim of a leg injury from the collision.
5. Biomechanical Evidence on Force Magnitude: The biomechanical engineer’s opinion, though not conclusive on its own, was persuasive. It confirmed that the low-impact nature of the accident, with no vehicle intrusion or significant occupant movement, meant the forces were insufficient to cause a femoral fracture, reinforcing the implausibility of the Claimant’s narrative.
6. Pre-existing Knee Conditions: The long-standing history of bilateral knee pain and osteoarthritis, combined with imaging that showed no acute fractures to either knee following the fall, allowed the Panel to confidently conclude that the knee injuries were not caused by the accident.

Legal Basis:
The Panel applied the test of causation articulated in the Motor Accident Injuries Act 2017 (MAI Act) and elaborated upon in the Motor Accidents Guidelines and relevant case law.
* Section 1.6 of the MAI Act: Defines “soft tissue injury” and “threshold injury,” which was central to classifying the non-disputed injuries.
* Section 3.28 of the MAI Act: States that statutory benefits for treatment and care cease after 26 weeks if the only injuries resulting from the motor accident were minor (threshold) injuries.
* Schedule 2, Clause 2(a) of the MAI Act: Declares whether an injury caused by the motor accident is a threshold injury as a medical assessment matter.
* Part 5 and 6 of the Motor Accidents Guidelines: Provide procedures for assessing threshold injury and principles of causation.
* Common Law Principles of Causation: The Panel referred to:
* Briggs v IAG Limited trading as NRMA Insurance (Briggs No 2) [2022] NSWSC 372, which emphasised that causation does not require scientific certainty, but must be more than negligible and a material contribution.
* Norrington v QBE Insurance (Australia) Ltd [2021] NSWSC 548, where Brereton J held that deciding causation solely on contemporaneous evidence is jurisdictional error, requiring consideration of the entire factual matrix.
* AAI Limited v McGiffen [2016] NSWCA 229, which clarified that the question extends to whether an injury was causally related to a “gait derangement” or similar indirect link caused by the accident.

Evidence Chain:
The Panel built a robust evidence chain to dismantle the Claimant’s causation argument for lower limb injuries:
1. Accident Severity: Police report and photographs indicated low impact, minor vehicle damage, and no intrusion into the cabin. This was supported by Catherine Imer’s statement.
2. Immediate Post-Accident State: Claimant drove home, attended GP, drove to police station, and moved around her house for over 24 hours. Crucially, the GP records and Monica North’s report confirmed no complaint of left thigh pain immediately after the accident.
3. Fall Incident: The Ambulance Report, documenting Ms Imer “tripped and fell,” contradicted her later assertion of a spontaneous leg collapse.
4. Medical Diagnosis: Hospital records consistently stated the femur fracture followed a fall. Subsequent imaging (CT and later X-rays) for the knees explicitly found “no acute injury identified” or “no acute fracture is identified.” The diagnosis of osteoporosis post-fall provided context for fracture susceptibility but not causation by the accident.
5. Biomechanical Analysis: Dr McIntosh’s report provided expert opinion that the forces in the accident were insufficient to cause femoral fractures.

Judicial Original Quotation:
The Panel’s reasoning was clear and decisive. Regarding the medical implausibility of the Claimant’s account, it stated:

“The Panel finds that being able to mobilise for well over 24 hours without significant left thigh or femoral pain is not consistent with the femoral fracture sustained by Ms Imer occurring at the time of the accident. Indeed, the Panel finds it would not be plausible to conclude that Ms Imer was able to walk on a displaced fracture of the femoral shaft. Furthermore, the Panel finds it implausible that the GP would have failed to identify a fracture of the left femur.”
This dictum directly highlights the critical role of medical common sense and the implausibility of the Claimant’s narrative. The objective facts of her post-accident mobility directly contradicted the possibility of the fracture occurring during the collision.

When addressing the lack of a causal link between the accident and the fall leading to the femoral fracture, the Panel concluded:

“The Panel finds there is no evidence of any soft tissue injury to the claimant’s leg which caused it to give way after the accident. Whilst Ms Imer has osteoporosis it would not cause her leg to give way and whilst it may have made her susceptible to fracture, the fracture would not occur without a fall. There is no evidence of injury to either thigh caused by the accident which would cause Ms Imer to sustain an osteoporotic fracture in the absence of a fall.”
This statement explicitly dismissed the argument that the accident caused a subtle injury leading to the fall, meticulously linking medical understanding of osteoporosis with the absence of accident-related leg injury.

On the role of biomechanical evidence:

“The Panel has also considered the opinion of Dr McIntosh as to the mechanics of the accident. Whilst the opinion of Dr McIntosh is not conclusive the Panel accepts there were insufficient forces applied to the lower limbs meaning it is unlikely the claimant could have sustained a femoral fracture in the accident. In particular, the Panel notes the only damage to the claimant’s vehicle was to the rear driver’s side panel, there was no intrusion into the claimant’s seated area, no evidence of significant movement without the vehicle interior, and the claimant was restrained by her seatbelt.”
This quotation illustrates how the Panel integrated expert evidence with factual observations of the accident to support its findings on the lack of causation, demonstrating a balanced yet firm approach to complex evidence.

Analysis of the Losing Party’s Failure:
The Claimant’s case failed primarily due to a significant disconnect between her recollected narrative and the objective, contemporaneous evidence.
1. Inconsistent Factual Accounts: The Claimant’s evolving account of hitting her leg on the centre console and her femur spontaneously “giving out” lacked corroboration from early medical records and statements. The contemporaneous ambulance report directly contradicted her version of the fall.
2. Lack of Contemporaneous Medical Evidence: The absence of complaints of left thigh or knee pain in the immediate aftermath of the accident, particularly in the GP notes from the following day, severely undermined any claim of an accident-induced lower limb injury leading to the fracture.
3. Medical Implausibility: The Claimant’s ability to remain mobile for an extended period after the accident was medically inconsistent with a fractured femur, a point strongly emphasised by the Medical Assessors.
4. Insufficient Causal Link for Fall: Even accepting a later diagnosis of osteoporosis, the Claimant failed to provide convincing evidence that the accident caused instability or weakness in her legs that directly led to her fall. The Panel found no evidence of an injury in the accident that would lead to an osteoporotic fracture in the absence of a fall.
5. Weak Challenge to Expert Evidence: The Claimant did not effectively challenge the biomechanical engineer’s opinion that the accident’s forces were insufficient to cause a femoral fracture, leaving the objective expert evidence largely uncontroverted on this point.

Implications

1. The Power of Contemporaneous Records: Always seek immediate medical attention and accurately report all injuries, however minor, to healthcare providers and emergency services. These initial records become powerful, objective evidence in any future legal dispute, often outweighing later recollections.
2. Causation is Not Just a Story: While personal narratives are important, legal causation requires objective evidence linking the incident to the injury. A compelling story alone may not be enough if it contradicts documented facts or scientific plausibility.
3. Be Consistent in Your Account: Any discrepancies in your account of an incident, especially between initial reports and later statements, can significantly weaken your credibility and undermine your claim.
4. Expert Evidence is Key: In complex injury cases, expert opinions (e.g., biomechanical engineers, medical specialists) can provide crucial insights into whether an injury could plausibly have occurred as described. Investing in independent expert assessments can be a decisive factor.
5. Pre-existing Conditions Matter: Be transparent about any pre-existing medical conditions. While an accident can aggravate pre-existing injuries, establishing that aggravation requires clear evidence of a worsening directly attributable to the incident.

Q&A Session

Q1: Why was the Claimant’s ability to walk after the accident so critical to the Panel’s decision regarding the femur fracture?
A1: The Panel, including experienced Medical Assessors, found it medically implausible that a person could walk or function normally for over 24 hours with a displaced fracture of the femoral shaft. This fact strongly contradicted the Claimant’s assertion that the fracture occurred during the accident, leading the Panel to conclude that the fracture must have resulted from the later fall.

Q2: How did the discrepancy in the description of the fall impact the Claimant’s case?
A2: The Claimant stated her leg “gave out” before the fall, implying an accident-related weakness. However, the Ambulance Report, a contemporaneous record, stated she “tripped and fell.” This contradiction undermined the Claimant’s credibility and the argument that the fall was a consequence of the accident, instead suggesting an independent event.

Q3: What role did the biomechanical engineer’s report play in the Panel’s decision, given it was not considered “conclusive”?
A3: While not conclusive in isolation, the biomechanical report was persuasive. It provided an expert opinion that the low-impact nature of the accident made it “highly unlikely” that sufficient forces were generated to cause a femoral fracture. This objective analysis, combined with the lack of contemporaneous complaints and the Claimant’s post-accident mobility, significantly strengthened the Insurer’s argument against causation and supported the Panel’s findings.

---

Appendix: Reference for Comparable Case Judgments and Practical Guidelines

1. Practical Positioning of This Case
Case Subtype: Personal Injury – Motor Accident Threshold Injury (Causation Dispute)
Judgment Nature Definition: Final Judgment

2. Self-examination of Core Statutory Elements

• Core Test (Negligence under the Civil Liability Act): (While this case is under the Motor Accident Injuries Act 2017, the underlying principles of causation for injury claims often draw parallels with negligence principles).
  • Duty of Care: Was a duty of care owed by the at-fault driver to other road users, including the Claimant? (Generally, yes, for road users).
  • Breach of Duty: Was there a breach of that duty (e.g., was the risk of collision foreseeable and not insignificant, and did the driver fail to take reasonable precautions)? (Implicitly established by the hit-and-run nature).
  • Causation (Section 5D Civil Liability Act 2002 (NSW) – Factual Causation & Scope of Liability):
    • Factual Causation (But-For Test): Was the injury (including the femur fracture and knee injuries) a direct result of the breach of duty? “Would this injury (or impairment) have occurred if not for the accident?” In this case, the Panel found many injuries would have occurred irrespective of the accident.
    • Scope of Liability: Is it appropriate for the scope of the negligent driver’s liability to extend to the harm so caused? This involves considering intervening acts, like the subsequent fall, and whether they break the chain of causation. The Panel effectively found that the fall was an intervening act that broke the causal link for the lower limb fractures.
• Core Test (Threshold Injury under the Motor Accident Injuries Act 2017):
  • Section 1.6(2) of the MAI Act: Defines a “soft tissue injury” as an injury to tissue that connects, supports or surrounds other structures or organs of the body, but not an injury to nerves or a complete or partial rupture of tendons, ligaments, menisci or cartilage.
  • Part 1, Clause 4 of the Motor Accident Injuries Regulation 2017: Expands threshold injury to include “an injury to the spinal nerve root that manifests in neurological signs (other than radiculopathy).”
  • Classification: If an injury is a soft tissue injury or a psychological/psychiatric injury that is not a recognised psychiatric illness, it is considered a threshold injury. Non-threshold injuries include fractures (unless specific exemptions apply). The Panel confirmed cervical spine and shoulder injuries were soft tissue and thus threshold. It found the lower limb fractures were not caused by the accident, thus removing them from consideration for the accident-related non-threshold injuries.
• Core Test (Damages – for non-economic loss):
  • Whole Person Impairment (WPI): For non-economic loss (pain and suffering), the injured person’s WPI must exceed a statutory threshold (e.g., 10% or 15% WPI, depending on jurisdiction and date of accident) to be eligible for such compensation. The finding that the femur fracture was not caused by the accident significantly impacts the potential WPI from the accident.

3. Equitable Remedies and Alternative Claims
This case primarily concerns statutory interpretation and factual causation within the motor accident compensation scheme. Equitable remedies such as promissory estoppel, proprietary estoppel, or unjust enrichment are generally less applicable where a specific statutory scheme governs compensation for personal injury. However, in other Civil Litigation and Dispute Resolution scenarios, when statutory law is found to be inapplicable or exhausted, parties may explore:

• Procedural Fairness (for Administrative Decisions): In this case, the Claimant’s right to procedural fairness was inherently built into the review process itself. The establishment of the Review Panel and its careful consideration of submissions and evidence (including allowing the Claimant to provide further input by videoconference) demonstrates adherence to principles of natural justice. Had there been a significant procedural defect in the original Medical Assessor’s process or the Review Panel’s conduct, grounds for judicial review of an administrative decision might arise. This would not be about a separate claim for damages but challenging the validity of the decision itself.

4. Access Thresholds and Exceptional Circumstances
* Regular Thresholds:
* Statutory Benefits Duration (MAI Act): For threshold injuries, statutory benefits for treatment and care cease after 26 weeks. This is a critical threshold.
* WPI Threshold for Non-Economic Loss (MAI Act): For non-economic loss (e.g., pain and suffering), the injured person must have a Whole Person Impairment (WPI) exceeding a certain statutory threshold (e.g., 10% or more) to be eligible for such compensation. The outcome of causation disputes directly impacts the calculation of WPI attributable to the accident.
* Exceptional Channels (Crucial):
* Limitation Period Expiry (Personal Injury): While not directly at issue in this judgment, a general threshold in personal injury is the limitation period for commencing proceedings (e.g., 3 years from the date of discoverability of injury). Extensions may be granted in specific circumstances, such as:
* Latent Damage: Where the injury or its severity only becomes apparent much later.
* Legal Incapacity: If the injured person was a minor or lacked mental capacity.
* Special Circumstances: Courts retain some discretion for “just and reasonable” extensions, though often constrained by legislation.
* Jurisdictional Error in Administrative Decisions (Administrative Law/Judicial Review): If a decision-maker (like a Medical Assessor or Review Panel) makes an error of law, breaches natural justice, or acts outside their powers, their decision may be subject to judicial review. The Norrington case referenced by the Panel highlights that ignoring the “gait derangement” argument (i.e., solely focusing on contemporaneous complaint) could constitute jurisdictional error.

Suggestion: Do not abandon a potential claim simply because you do not meet the standard time or conditions. Carefully compare your circumstances against the exceptions above, as they are often the key to successfully filing a case.

5. Guidelines for Judicial and Legal Citation
* Citation Angle: It is recommended to cite this case in legal submissions or debates involving:
* Causation disputes in motor accident injury claims, particularly where there is a delayed presentation of significant injury or an intervening event (e.g., a fall).
* Arguments concerning the weight given to contemporaneous medical records versus later recollections in establishing the causal link of injuries.
* Cases involving the role and persuasiveness of biomechanical engineering evidence in low-impact collision scenarios.
* Interpretation of “threshold injury” and “soft tissue injury” definitions under the Motor Accident Injuries Act 2017.
* Citation Method:
* As Positive Support: When your matter involves similar facts (e.g., claimant’s post-accident mobility contradicts severe injury; lack of immediate injury complaint; intervening fall), citing Imer v Insurance Australia Limited t/as NRMA Insurance [2025] NSWPICMP 24 can strengthen arguments that a later injury is not causally linked to the motor accident.
* As a Distinguishing Reference: If the opposing party cites this case, you should emphasize factual differences such as:
* Strong contemporaneous evidence of immediate injury (e.g., explicit mention of leg pain in initial GP notes, visible bruising, immediate inability to mobilise).
* Expert medical evidence supporting a plausible mechanism for the injury occurring in the accident (e.g., specific force vectors, unique occupant kinematics).
* Evidence of accident-induced instability or derangement that directly led to a subsequent event (e.g., dizziness or gait impairment immediately after the accident causing a fall).
* The uniqueness of the current matter to argue that this precedent is not applicable.
* Anonymisation Rule: Do not use the real names of the parties; strictly use professional procedural titles such as Claimant / Insurer or Appellant / Respondent.

Conclusion
The judgment in Imer v Insurance Australia Limited t/as NRMA Insurance [2025] NSWPICMP 24 powerfully illustrates that establishing causation in personal injury claims hinges on a consistent, credible, and objectively supported narrative. It serves as a stark reminder that while a claimant’s suffering is real, legal causation demands a robust evidentiary chain, often favouring contemporaneous records and expert analysis over later recollections. True self-protection stems from the early understanding and mastery of legal rules.

Disclaimer
This article is based on the study and analysis of the public judgment of the Personal Injury Commission ([Imer v Insurance Australia Limited t/as NRMA Insurance [2025] NSWPICMP 24]), aimed at promoting legal research and public understanding. The citation of relevant judgment content is limited to the scope of fair dealing for the purposes of legal research, comment, and information sharing.
The analysis, structural arrangement, and expression of views contained in this article are the original content of the author, and the copyright belongs to the author and this platform. This article does not constitute legal advice, nor should it be regarded as legal advice for any specific situation.

---

Original Case File:

👉 Can’t see the full document?
Click here to download the original judgment document.