Reference Determination Content
Suggested draft · fictitious patient
Left Ankle - Os Trigonum Syndrome
Evidence
The evidence that I have considered in making this decision includes:
- Formal Claim with supporting statements;
- A Statement of your Service from the Department of Defence;
- Copies of your Service Medical Records.
- A Diagnostic Assessment by Dr Thomas Perkins, General Practitioner, Veterans Health Centre, dated 19 June 2025;
- A Diagnosis Form (D9287) by Dr Thomas Perkins, General Practitioner, Veterans Health Centre, dated 19 June 2025;
- An emergency treatment record and X-ray left ankle report by the medical officer and radiologist, dated 14 August 2005;
- A physiotherapy assessment by the physiotherapist, Garrison health centre, dated 20 April 2006;
- A pre-deployment health assessment by the medical officer, Garrison health centre, dated 28 August 2006;
- A patrol medic casualty record by the afghanistan, dated 6 February 2007;
- A deployed health record by the medical officer, Afghanistan, dated 20 March 2007;
- An X-ray and MRI left ankle report and orthopaedic consultation by the radiologist and orthopaedic foot and ankle surgeon, dated 5 June 2007;
- A deployed health record by the medical officer, Afghanistan, dated 17 August 2010;
- An MRI left ankle report and orthopaedic review by the radiologist and orthopaedic foot and ankle surgeon, dated 26 January 2011;
- An operation report by the orthopaedic foot and ankle surgeon, dated 14 April 2011.
Your service
I have identified that you have the following service:
Australian Defence Force service between :
8 May 2000 and 30 March 2014
Left Ankle - Os Trigonum Syndrome
You have stated that your condition was caused by:
- having an acute hyperplantarflexion injury of the affected ankle within the 1 year before the clinical onset of os trigonum syndrome
- having a sprain of the lateral or posterior ligaments of the affected ankle within the 1 year before the clinical onset of os trigonum syndrome
- having a fracture of the distal tibia, distal fibula, talus or posterior talar process of the affected ankle within the 2 years before the clinical onset of os trigonum syndrome
- having chronic lateral instability of the affected ankle at the time of the clinical onset of os trigonum syndrome
- undertaking repetitive activities involving forced or end-range plantarflexion of the affected ankle, including parachute landings, jumping from a height, kicking or running on steep or uneven ground, for at least 10 hours per week for at least the 3 months before the clinical onset of os trigonum syndrome
- carrying loads of at least 20 kilograms while marching or patrolling for a cumulative total of at least 200 hours within the 6 months before the clinical onset of os trigonum syndrome
- undertaking at least 20 parachute descents within the 5 years before the clinical onset of os trigonum syndrome
- having flexor hallucis longus tenosynovitis or posterior ankle synovitis of the affected ankle at the time of the clinical onset of os trigonum syndrome
Diagnosis: Os Trigonum Syndrome
Basis of diagnosis: The diagnosis was made in the Diagnostic Assessment by Dr Thomas Perkins dated 19 June 2025, and is supported by an X-ray and MRI left ankle report and orthopaedic consultation by the radiologist and orthopaedic foot and ankle surgeon, dated 5 June 2007.
I am satisfied this is the appropriate diagnosis.
There is no Statement of Principles (SOP) for this condition. In determining your claim for this condition, I have therefore considered the available evidence, applying the standard of proof:
Reasonable Hypothesis - no Statement of Principles determined for this condition
which requires the evidence to connect the condition with service.
I am satisfied that the evidence establishes the following link to your service:
- having an acute hyperplantarflexion injury of the affected ankle within the 1 year before the clinical onset of os trigonum syndrome
- having a sprain of the lateral or posterior ligaments of the affected ankle within the 1 year before the clinical onset of os trigonum syndrome
- having a fracture of the distal tibia, distal fibula, talus or posterior talar process of the affected ankle within the 2 years before the clinical onset of os trigonum syndrome
- having chronic lateral instability of the affected ankle at the time of the clinical onset of os trigonum syndrome
- undertaking repetitive activities involving forced or end-range plantarflexion of the affected ankle, including parachute landings, jumping from a height, kicking or running on steep or uneven ground, for at least 10 hours per week for at least the 3 months before the clinical onset of os trigonum syndrome
- carrying loads of at least 20 kilograms while marching or patrolling for a cumulative total of at least 200 hours within the 6 months before the clinical onset of os trigonum syndrome
- undertaking at least 20 parachute descents within the 5 years before the clinical onset of os trigonum syndrome
- having flexor hallucis longus tenosynovitis or posterior ankle synovitis of the affected ankle at the time of the clinical onset of os trigonum syndrome
I have noted your contention as to the cause of this condition. The available evidence indicates, I have noted your contention to the cause of your condition. Your service medical records indicate that you presented to the health facility with deep pain at the back and outer side of the left ankle, brought on by pointing the foot, pushing off, walking downhill, descending stairs and ladders and kneeling, with pain at the back of the ankle when the big toe moved on 20 March 2007.
The diagnosis was made by an orthopaedic foot and ankle surgeon on 5 June 2007 on the basis of posterolateral ankle pain reproduced by forced passive plantarflexion, tenderness behind the peroneal tendons and pain with movement of the big toe, supported by MRI showing a large os trigonum with bone marrow oedema across the synchondrosis, posterior synovitis and flexor hallucis longus tenosynovitis. Complete temporary relief after an ultrasound-guided injection into the posterior recess confirmed the os trigonum as the source of pain.
This has then led to further investigations and the diagnosis of your condition of Os Trigonum Syndrome. I have accepted your condition of Os Trigonum Syndrome.
Having considered your service records and the available medical evidence, I am satisfied the evidence establishes that this condition is related to your wartime service.
I have therefore accepted that this condition is related to your service with effect from 19 March 2007.
Left Ankle - Os Trigonum Syndrome (Worsening)
Evidence
The evidence that I have considered in making this decision includes:
- Formal Claim with supporting statements;
- A Statement of your Service from the Department of Defence;
- Copies of your Service Medical Records.
- A Diagnostic Assessment by Dr Thomas Perkins, General Practitioner, Veterans Health Centre, dated 19 June 2025;
- A Diagnosis Form (D9287) by Dr Thomas Perkins, General Practitioner, Veterans Health Centre, dated 19 June 2025;
- An emergency treatment record and X-ray left ankle report by the medical officer and radiologist, dated 14 August 2005;
- A physiotherapy assessment by the physiotherapist, Garrison health centre, dated 20 April 2006;
- A pre-deployment health assessment by the medical officer, Garrison health centre, dated 28 August 2006;
- A patrol medic casualty record by the afghanistan, dated 6 February 2007;
- A deployed health record by the medical officer, Afghanistan, dated 20 March 2007;
- An X-ray and MRI left ankle report and orthopaedic consultation by the radiologist and orthopaedic foot and ankle surgeon, dated 5 June 2007;
- A deployed health record by the medical officer, Afghanistan, dated 17 August 2010;
- An MRI left ankle report and orthopaedic review by the radiologist and orthopaedic foot and ankle surgeon, dated 26 January 2011;
- An operation report by the orthopaedic foot and ankle surgeon, dated 14 April 2011.
Your service
I have identified that you have the following service:
Australian Defence Force service between :
8 May 2000 and 30 March 2014
Left Ankle - Os Trigonum Syndrome (Worsening)
You have stated that the worsening of your condition was caused by:
- having an acute hyperplantarflexion injury of the affected ankle within the 1 year before the clinical worsening of os trigonum syndrome
- carrying loads of at least 20 kilograms while marching or patrolling for a cumulative total of at least 200 hours within the 6 months before the clinical worsening of os trigonum syndrome
- undertaking repetitive activities involving forced or end-range plantarflexion of the affected ankle, including parachute landings, jumping from a height, kicking or running on steep or uneven ground, for at least 10 hours per week for at least the 3 months before the clinical worsening of os trigonum syndrome
- inability to obtain appropriate clinical management for os trigonum syndrome
Diagnosis: Os Trigonum Syndrome (Worsening)
Basis of diagnosis: The diagnosis was made in the Diagnostic Assessment by Dr Thomas Perkins dated 19 June 2025, and is supported by an X-ray and MRI left ankle report and orthopaedic consultation by the radiologist and orthopaedic foot and ankle surgeon, dated 5 June 2007.
I am satisfied this is the appropriate diagnosis.
There is no Statement of Principles (SOP) for this condition. In determining your claim for this condition, I have therefore considered the available evidence, applying the standard of proof:
Reasonable Hypothesis - no Statement of Principles determined for this condition
which requires the evidence to connect the condition with service.
I am satisfied that the evidence establishes the following link to your service:
- having an acute hyperplantarflexion injury of the affected ankle within the 1 year before the clinical worsening of os trigonum syndrome
- carrying loads of at least 20 kilograms while marching or patrolling for a cumulative total of at least 200 hours within the 6 months before the clinical worsening of os trigonum syndrome
- undertaking repetitive activities involving forced or end-range plantarflexion of the affected ankle, including parachute landings, jumping from a height, kicking or running on steep or uneven ground, for at least 10 hours per week for at least the 3 months before the clinical worsening of os trigonum syndrome
- inability to obtain appropriate clinical management for os trigonum syndrome
I have noted your contention as to the cause of this condition. The available evidence indicates, I have noted your contention to the cause of your condition. Your service medical records indicate that you presented to the health facility with deep pain at the back and outer side of the left ankle, brought on by pointing the foot, pushing off, walking downhill, descending stairs and ladders and kneeling, with pain at the back of the ankle when the big toe moved on 20 March 2007.
The diagnosis was made by an orthopaedic foot and ankle surgeon on 5 June 2007 on the basis of posterolateral ankle pain reproduced by forced passive plantarflexion, tenderness behind the peroneal tendons and pain with movement of the big toe, supported by MRI showing a large os trigonum with bone marrow oedema across the synchondrosis, posterior synovitis and flexor hallucis longus tenosynovitis. Complete temporary relief after an ultrasound-guided injection into the posterior recess confirmed the os trigonum as the source of pain.
After the condition arose, it was worsened during your service. On 17 August 2010, during warlike service in Afghanistan, you jumped from a helicopter ramp at a landing zone carrying 52 kilograms and forced your left ankle into hyperplantarflexion. From 17 February 2010 to 17 August 2010, through your pre-deployment training and your warlike service in Afghanistan from 3 May 2010, you marched and patrolled with 45 to 55 kilograms for a cumulative total of more than 450 hours, recorded in training and patrol records. From 17 May 2010 to 17 August 2010, on warlike service in Afghanistan, you patrolled for more than 30 hours a week over steep terraced ground and irrigation ditches, with repeated helicopter insertions and drops from compound walls, as recorded in patrol reports. On warlike service in Afghanistan in 2010 you could not obtain imaging, a guided injection or orthopaedic review for your known os trigonum syndrome, and no non-patrolling role was available until your pain made patrolling impossible in September 2010.
This has then led to further investigations and the diagnosis of your condition of Os Trigonum Syndrome (Worsening). I have accepted your condition of Os Trigonum Syndrome (Worsening).
Having considered your service records and the available medical evidence, I am satisfied the evidence establishes that the worsening of this condition is related to your wartime service.
I have therefore accepted that the worsening of this condition is related to your service with effect from 17 August 2010.
