Diagnostic Assessment — Right Ankle - Flexor Hallucis Longus Tendinopathy
Example 1 of 1 · fictitious patient (Veteran BI)
Diagnostic Assessment
Right Ankle - Flexor Hallucis Longus Tendinopathy
BOP Code: 28 of 2020 (Sprain and Strain)
RH Code: 27 of 2020 (Sprain and Strain)
ADF History
Veteran BI, date of birth 21 October 1982, Australian Army, Infantry Soldier (Rifleman, later Section Commander; parachute and commando qualified), enlisted 12 March 2001, medically discharged 20 June 2016. Operational service: Solomon Islands, 24 July 2003 to 30 November 2003 (non-warlike); Afghanistan, 01 April 2009 to 30 September 2009 (warlike); Afghanistan, 01 February 2012 to 15 July 2012 (warlike).
Occupational History
As an infantry soldier in a commando regiment the veteran patrolled on foot for long distances over rocky and mountainous terrain carrying loads of 40 to 60 kilograms, conducted parachute descents by day and night, jumped from helicopter ramps and vehicle tailgates, and climbed steep slopes and compound walls. These tasks place repeated high loads on the ankle ligaments and on the long flexor tendons of the foot, particularly in push-off, landing and climbing on the forefoot.
The trade carries a high rate of acute ankle sprains and tendon strains from falls, landings and uneven ground, often sustained at night and in body armour. On operations, injuries were commonly managed with strapping and analgesia so that the soldier could continue patrolling, and imaging, physiotherapy and specialist review were not available in forward locations.
History
Veteran BI, an infantry section commander in the Australian Army, sustained a strain of the right flexor hallucis longus tendon, with a sprain of the right lateral ankle ligaments, when he jumped from the ramp of a helicopter onto rocky ground at night carrying 55 kilograms on warlike service in Afghanistan on 14 June 2009. The strain progressed to a chronic tendinopathy with a partial split tear, and it worsened after a second injury while climbing on warlike service in Afghanistan on 18 March 2012.
Timeline
- 02 Feb 2009 — At his pre-deployment medical the veteran had no history of ankle or foot injury beyond minor sprains as a recruit. Examination showed full, pain-free ankle and great toe movement, stable ankle ligaments on anterior drawer and talar tilt testing, and no posterior ankle tenderness. "ankles stable, full range"
- 14 Jun 2009 — On warlike service in Afghanistan, during a night helicopter insertion, the veteran jumped about 1.5 metres from the ramp carrying 55 kg of equipment. His right forefoot landed on a rock with the great toe and ankle forced into dorsiflexion as he pushed off, and the ankle then rolled into inversion. He had immediate pain behind the medial malleolus and over the lateral ankle, with swelling within hours. The patrol medic recorded tenderness along the course of flexor hallucis longus and over the anterior talofibular ligament, and painful resisted great toe flexion. "posterior medial ankle pain, inversion"
- 16 Jun 2009 — At the role 2 facility X-rays showed no fracture and a small os trigonum. A medical officer diagnosed a strain of the right flexor hallucis longus and a grade 2 sprain of the anterior talofibular ligament. He was strapped, given anti-inflammatory medication and returned to patrolling within four days because of operational demands. No physiotherapy or imaging beyond plain films was available. "FHL strain, ATFL grade 2"
- 10 Nov 2009 — After return to Australia the veteran reported persistent pain behind the right medial malleolus on running, landing and climbing, and triggering of the great toe. MRI showed a partial longitudinal split tear of flexor hallucis longus at the fibro-osseous tunnel with tenosynovitis, and a thickened, healed anterior talofibular ligament. Ankle stress tests were stable. "FHL split tear, tenosynovitis"
- 08 Apr 2010 — A sports physician confirmed chronic tendinopathy of the right flexor hallucis longus following the 2009 strain. Pain was reproduced with resisted great toe flexion and with passive great toe dorsiflexion in ankle dorsiflexion. He completed a 12-week loading program, was graded fit for field duties and returned to parachuting. "chronic FHL tendinopathy confirmed"
- 18 Mar 2012 — On warlike service in Afghanistan the veteran slipped while climbing a steep, loose slope carrying 50 kg. His right forefoot jammed in a rock crevice with the great toe and ankle forced into dorsiflexion, and his body weight rolled the ankle. He had sudden, severe posterior medial ankle pain and lateral ankle swelling. With no imaging or physiotherapy available, he was strapped and continued patrolling for nine days before light duties were possible. "slipped climbing, severe FHL pain"
- 04 Aug 2012 — MRI after his return showed extension of the flexor hallucis longus split tear over 4 cm with a larger tenosynovial effusion and stenosis at the fibro-osseous tunnel, and an acute sprain of the anterior talofibular ligament. The sports physician recorded worsening: he could no longer run, the Foot and Ankle Ability Measure had fallen from 82 to 54 per cent, and great toe triggering occurred with every step on stairs. "split tear extended, FAAM 54"
- 19 Feb 2013 — An orthopaedic foot and ankle surgeon performed a right flexor hallucis longus tenosynovectomy with release of the fibro-osseous tunnel, repair of the split tear and excision of the os trigonum. He was later medically downgraded and was unable to return to parachuting or patrolling. "FHL release and repair"
Symptoms
At onset the veteran had sudden pain behind the right medial malleolus and in the arch, worse with pushing off and with resisted great toe flexion, together with lateral ankle pain and swelling. He limped and could not run or land from a jump without pain. Over the following months he developed pain on running, climbing and landing, posterior ankle pain with forefoot loading and triggering of the great toe.
He now reports persistent posterior medial ankle pain after walking more than 30 minutes, pain and stiffness of the great toe, inability to run, climb ladders or carry loads, and difficulty on stairs and uneven ground.
Imaging
- 16 Jun 2009 — X-ray right ankle and foot: "No fracture. Small os trigonum posterior to the talus. Lateral soft tissue swelling."
- 10 Nov 2009 — MRI right ankle: "Partial longitudinal split tear of the flexor hallucis longus tendon at the fibro-osseous tunnel behind the talus, with tenosynovitis and fluid in the tendon sheath. Thickened anterior talofibular ligament consistent with a healed sprain. Os trigonum."
- 04 Aug 2012 — MRI right ankle: "Extension of the flexor hallucis longus split tear over 4 cm with a larger tenosynovial effusion, stenosing tenosynovitis at the fibro-osseous tunnel and marrow oedema in the os trigonum. Acute sprain of the anterior talofibular ligament with periligamentous oedema."
Onset Date
The most likely date of onset of this condition is 14 Jun 2009.
At that date the veteran was on warlike service in Afghanistan as an infantry section commander. During a night helicopter insertion he jumped from the ramp carrying 55 kg, his right forefoot landed on a rock with the great toe and ankle forced into dorsiflexion, and the ankle rolled into inversion. Pain and tenderness along flexor hallucis longus and over the lateral ligaments began immediately, well within the 24 hours following the injury.
This date is appropriate because his pre-deployment medical of 02 February 2009 recorded full, pain-free ankle and great toe movement, stable ligaments and no posterior ankle tenderness, and the patrol medic recorded the injury on the night it occurred. The symptoms were continuous from that date and were confirmed as a strain on 16 June 2009 and as a split tear with tenosynovitis on MRI on 10 November 2009.
The causative factors in these instruments do not set a period before onset; they require the force or forceful use to occur at the time of onset. The force through the ankle joint and the forceful loading of the flexor hallucis longus tendon both occurred at the moment of the injury on 14 June 2009, during warlike service, and pain and tenderness followed immediately.
For the worsening factors, the documented worsening followed the injury of 18 Mar 2012, again at the time of the event and on warlike service, with immediate severe pain and swelling. The worsening was confirmed by MRI on 04 Aug 2012 and by the fall in the Foot and Ankle Ability Measure from 82 to 54 per cent. The ankle ligaments had been stable on testing before the 2012 injury, so the second sprain was not a recurrent sprain due to instability.
1. What is the formal diagnosis of the condition claimed above?
The formal diagnosis is Strain of the Right Flexor Hallucis Longus Tendon with consequent chronic tendinopathy and partial split tear (ICD-10-AM S96.0), with an associated sprain of the right anterior talofibular ligament, under the Statements of Principles concerning sprain and strain, Balance of Probabilities No. 28 of 2020 and Reasonable Hypothesis No. 27 of 2020.
Flexor hallucis longus is the muscle that flexes the great toe and assists push-off. Its tendon passes behind the ankle through a fibro-osseous tunnel between the tubercles of the talus and then under the arch to the great toe. A strain is a tearing or stretching of a muscle or tendon from forceful stretching or high intensity use, with pain and tenderness within 24 hours. Strains of the flexor hallucis longus tendon occur with forced dorsiflexion of the great toe and ankle during push-off, landing and climbing, and when not adequately rested can progress to a chronic tendinopathy with longitudinal splitting, tenosynovitis and stenosis in the tunnel, causing posterior medial ankle pain and triggering of the great toe.
The condition began with a strain of the tendon on warlike service in Afghanistan on 14 June 2009, progressed to a chronic tendinopathy confirmed on 08 April 2010, and worsened after a second strain on warlike service in Afghanistan on 18 March 2012.
2. For each diagnosis identified, please also provide the following dates:
When did the veteran first experience symptoms attributable to this condition?
14 June 2009.
When did the veteran first present to a health / medical provider for this condition?
14 June 2009.
When was the condition confirmed / formally diagnosed?
16 June 2009.
When did the veteran first present to you (or your practice) for this condition?
17 September 2025.
3. How was this diagnosis confirmed? i.e. what were the key symptoms and signs, investigation results, specialist opinions?
The strain was diagnosed by a medical officer on 16 June 2009 on the basis of immediate pain and tenderness along the course of flexor hallucis longus after a forceful dorsiflexion injury, with pain on resisted great toe flexion. This meets the Statement of Principles definition of strain: tearing or stretching of a tendon with pain and tenderness at that site within the 24 hours following the injury. The associated lateral ligament injury meets the definition of sprain. MRI on 10 November 2009 confirmed tearing of the tendon, showing a partial longitudinal split tear with tenosynovitis.
A sports physician confirmed chronic tendinopathy on 08 April 2010, with pain on resisted great toe flexion and on passive great toe dorsiflexion with the ankle dorsiflexed. The worsening after the second injury was confirmed on MRI on 04 August 2012 and at surgery on 19 February 2013, when the split tear was repaired.
4. What do you consider to be the cause(s) of the condition in this veteran? Give consideration to constitutional and common risk factors, pre-existing injuries or diseases, and occupational or lifestyle risks, as well as direct causative mechanisms.
Legislation: the clinical onset of this condition was on 14 June 2009, after 1 July 2004, during warlike service in Afghanistan. This is a Military Rehabilitation and Compensation Act 2004 (MRCA) claim and the Statements of Principles apply. The Balance of Probabilities instrument applies to peacetime service, including his parachuting and field training in Australia. The Reasonable Hypothesis instrument applies to his warlike service in Afghanistan in 2009, where the strain occurred, and in 2012, where it worsened.
Each factor must be related to the person's relevant service. Under the beneficial approach required by the legislation, the absence of documentation does not mean that an event or exposure did not occur: lack of evidence is not evidence of lack.
Balance of Probabilities — Statement of Principles concerning Sprain and Strain, No. 28 of 2020
Causative factors
Factor 9(1): experiencing a significant physical force applied to or through the affected joint, at the time of the clinical onset of a sprain to that joint ligament; — MET
- On 14 June 2009 the veteran jumped about 1.5 metres from a helicopter ramp carrying 55 kg and landed on a rock, and his right ankle was forced into dorsiflexion and then inversion under his full loaded body weight. This was a significant physical force applied through the right ankle joint at the moment the anterior talofibular ligament was sprained. Lateral ankle pain and swelling began immediately and a grade 2 sprain was diagnosed on 16 June 2009. The jump was part of a tactical insertion carried out under orders as part of his duties as a section commander.
Factor 9(2): forceful stretching or high intensity use of a muscle or tendon at the time of the clinical onset of a strain to that muscle or tendon; — MET
- In the same landing the veteran was pushing off his right forefoot as the great toe and ankle were forced into dorsiflexion against the contracting flexor hallucis longus, a forceful eccentric stretch of the tendon under a load of about 140 kg including his equipment. Pain and tenderness behind the medial malleolus and along the tendon began immediately. The strain was diagnosed on 16 June 2009 and the tendon tear confirmed on MRI on 10 November 2009.
Worsening factors
Factor 9(3): experiencing a significant physical force applied to or through the affected joint, at the time of the clinical worsening of a sprain to that joint ligament; — MET
- On 18 March 2012 the veteran slipped on a loose slope while carrying 50 kg and his right forefoot jammed in a rock crevice, so that his falling body weight was applied through the right ankle in dorsiflexion and inversion. The anterior talofibular ligament was sprained again, with immediate swelling and an acute sprain with periligamentous oedema on MRI on 04 August 2012. The ankle had been stable on testing on 10 November 2009 and 08 April 2010, so this was a new sprain and not a recurrent sprain due to instability.
Factor 9(4): forceful stretching or high intensity use of a muscle or tendon at the time of the clinical worsening of a strain to that muscle or tendon; — MET
- In the slip of 18 March 2012 the right great toe and ankle were forced into dorsiflexion while the veteran was driving up the slope through his forefoot, a forceful stretch of the already strained flexor hallucis longus tendon. He had sudden, severe pain at the fibro-osseous tunnel, and MRI on 04 August 2012 showed extension of the split tear over 4 cm with a larger tenosynovial effusion. His Foot and Ankle Ability Measure fell from 82 to 54 per cent.
Factor 9(5): inability to obtain appropriate clinical management for sprain or strain. — MET
- After both injuries the veteran was in forward locations where no imaging other than plain films, no physiotherapy and no sports medicine review were available. In 2009 he was strapped and returned to patrolling within four days, and in 2012 he continued patrolling for nine days before light duties could be arranged. The strain was not rested or rehabilitated in the acute phase, it progressed to a chronic split tear, and the second injury extended the tear. Under Brew v Repatriation Commission (1999) this is an inability to obtain appropriate clinical management.
Reasonable Hypothesis — Statement of Principles concerning Sprain and Strain, No. 27 of 2020
Causative factors
Factor 9(1): experiencing a significant physical force applied to or through the affected joint, at the time of the clinical onset of a sprain to that joint ligament; — MET
- The landing from the helicopter ramp onto a rock carrying 55 kg on 14 June 2009 occurred during a night tactical insertion on warlike service in Afghanistan. The force of the landing was applied through the right ankle at the moment the anterior talofibular ligament was sprained, with immediate pain and swelling recorded by the patrol medic.
Factor 9(2): forceful stretching or high intensity use of a muscle or tendon at the time of the clinical onset of a strain to that muscle or tendon; — MET
- The forced dorsiflexion of the right great toe and ankle during push-off in the same landing, on warlike service in Afghanistan on 14 June 2009, forcefully stretched the contracting flexor hallucis longus tendon. Pain and tenderness along the tendon began immediately, and the strain was diagnosed at the role 2 facility on 16 June 2009.
Worsening factors
Factor 9(3): experiencing a significant physical force applied to or through the affected joint, at the time of the clinical worsening of a sprain to that joint ligament; — MET
- The slip on a loose slope with the right forefoot jammed in a crevice on 18 March 2012 occurred on a foot patrol on warlike service in Afghanistan. His loaded body weight was applied through the right ankle at the moment of the second anterior talofibular ligament sprain.
Factor 9(4): forceful stretching or high intensity use of a muscle or tendon at the time of the clinical worsening of a strain to that muscle or tendon; — MET
- The forced dorsiflexion of the great toe and ankle while climbing under a 50 kg load on warlike service in Afghanistan on 18 March 2012 forcefully stretched the flexor hallucis longus tendon, causing sudden severe pain and extension of the split tear confirmed on MRI on 04 August 2012.
Factor 9(5): inability to obtain appropriate clinical management for sprain or strain. — MET
- On warlike service in Afghanistan in 2009 and 2012 the veteran had no access to MRI, physiotherapy or specialist review, and operational demands required him to keep patrolling on the injured ankle within days of each injury. The strain progressed to a chronic tendinopathy and then worsened.
The % contribution of the causes is 100% and significant.
Sequelae
The flexor hallucis longus tendinopathy is a sequela of the veteran's accepted strain of the right flexor hallucis longus tendon and sprain of the right ankle sustained on warlike service in 2009 and 2012. In turn it has caused an altered gait with offloading of the right forefoot, with lateral foot pain and right knee pain recorded from 2014, and stiffness of the right great toe after surgery.
Unintended Consequence
Not met as a separate pathway. The worsening of the condition followed a further service injury and a lack of available treatment, not a complication of treatment provided by the Commonwealth. Postoperative stiffness of the great toe after the surgery of 19 February 2013 is recorded and may be considered separately.
Inability to Attain Appropriate Medical Management
MET. After the injury of 14 June 2009 the veteran was in a forward location on warlike service in Afghanistan with no access to MRI, physiotherapy or sports medicine review, and he was strapped and returned to patrolling within four days. After the second injury on 18 March 2012 he continued patrolling for nine days before light duties could be arranged. In both cases the strained tendon was loaded through the acute phase instead of being rested and rehabilitated, and the condition progressed to a chronic split tear and then worsened. Applying the objective and subjective tests in Brew v Repatriation Commission (Full Federal Court, 10 September 1999, Merkel J), the unavailability of appropriate treatment and rest because of operational circumstances amounts to an inability to obtain appropriate clinical management. The five-month delay to MRI after the 2009 injury also reflects barriers to care on deployment.
5. Please provide a Health Summary and a medication / prescribing history.
See attached report.
References
- 02 Feb 2009, Pre-deployment medical examination, Medical Officer, Garrison health centre
- 14 Jun 2009, Patrol casualty record, Patrol medic, Afghanistan
- 16 Jun 2009, Deployed health record and X-ray report, Medical Officer, Role 2 facility, Afghanistan
- 10 Nov 2009, Outpatient health record and MRI right ankle report, Medical Officer and Radiologist
- 08 Apr 2010, Specialist consultation, Sports physician
- 18 Mar 2012, Deployed health record, Medical Officer, Forward operating base, Afghanistan
- 04 Aug 2012, MRI right ankle report and specialist review, Radiologist and Sports physician
- 19 Feb 2013, Operation report, Orthopaedic foot and ankle surgeon
- Statement of Principles concerning Sprain and Strain (Balance of Probabilities) No. 28 of 2020, Repatriation Medical Authority
- Statement of Principles concerning Sprain and Strain (Reasonable Hypothesis) No. 27 of 2020, Repatriation Medical Authority
