Diagnostic Assessment — Left Foot - Fifth Metatarsal Strain (Metatarsalgia)
Example 1 of 1 · fictitious patient (Veteran BQ)
Diagnostic Assessment
Left Foot - Fifth Metatarsal Strain (Metatarsalgia)
BOP Code: 28 of 2020 (Sprain and Strain)
RH Code: 27 of 2020 (Sprain and Strain)
ADF History
Veteran BQ, date of birth 27 November 1987, Australian Army, Rifleman (Infantry), parachute qualified, enlisted 11 July 2005, medically discharged 19 February 2016. Operational service: Afghanistan, 01 April 2009 to 20 November 2009 (warlike); Afghanistan, 10 February 2013 to 05 July 2013 (warlike).
Occupational History
Infantry soldiers patrol on foot for long periods over rough, rocky and uneven ground, carrying loads of 30 to 45 kilograms made up of body armour, weapon, ammunition, water, radio batteries and pack. Dismounted patrols in Afghanistan involved repeatedly climbing and jumping down from compound walls, irrigation ditches and vehicles, and running under load to cover and to aircraft.
Parachute training adds landing forces several times body weight through the feet and ankles. These activities apply high and sudden inversion and impact forces through the joints of the foot and place the peroneal tendons, which stabilise the outer border of the foot against inversion, under forceful stretch and high-intensity contraction. Foot and ankle sprains and strains are among the most common injuries in infantry soldiers, and on operations access to physiotherapy, imaging and rest from patrolling is limited.
History
Veteran BQ, an infantry rifleman in the Australian Army, sprained the ligaments of the left fifth tarsometatarsal joint and strained the peroneus brevis tendon at its insertion into the base of the fifth metatarsal on 18 July 2009, when he jumped down from a compound wall under load during warlike service in Afghanistan, leaving him with persisting lateral forefoot pain (metatarsalgia). The injury worsened on 22 June 2013 when his left foot was forced into inversion as he ran under load to a helicopter on his second tour of Afghanistan.
Timeline
- 02 Mar 2009 — Pre-deployment medical examination before Afghanistan. The veteran reported no foot or ankle problems. Examination of both feet and ankles was normal, with no tenderness, full movement and normal single-leg hop. He had completed his parachute course and a pre-deployment field exercise without injury. "feet and ankles NAD"
- 18 Jul 2009 — During a dismounted patrol in Afghanistan the veteran jumped down from a 1.8 metre compound wall carrying about 40 kg and landed on a rock with his left foot plantarflexed and forced into inversion. He felt a tearing pain on the outer border of the foot and could not weight bear fully. At the patrol base that evening there was swelling and bruising over the base of the left fifth metatarsal, tenderness over the fifth tarsometatarsal joint and the peroneus brevis insertion, and pain on resisted eversion and passive inversion. X-ray at the role 2 facility the next day showed no fracture. "inversion injury L foot, no fracture"
- 21 Aug 2009 — Review by the medical officer at the patrol base. The veteran had continued patrolling with his foot taped because there was no replacement in his section and no physiotherapist in the area of operations. He reported pain on the outer border of the left foot after every patrol and at night, and was walking on the inner border of the foot. Tenderness persisted over the fifth tarsometatarsal joint and the peroneus brevis insertion. Analgesia and taping continued. "ongoing lateral foot pain, taped"
- 15 Jan 2010 — After return to Australia, MRI of the left foot showed a sprain of the dorsal and plantar ligaments of the fifth tarsometatarsal joint with bone marrow oedema at the base of the fifth metatarsal, and thickening with partial tearing of the peroneus brevis tendon at its insertion. A sports physician diagnosed a sprain of the left fifth tarsometatarsal joint and a strain of the peroneus brevis tendon at the base of the fifth metatarsal, with secondary lateral metatarsalgia from offloading. Stress testing showed no joint instability. "5th TMT sprain, PB strain"
- 10 Sep 2010 — After eight months of physiotherapy, custom orthoses and graded return to running, the veteran returned to full duties. He reported residual aching under the lateral forefoot and the base of the fifth metatarsal after long patrols and runs, rated 2 out of 10, and the podiatrist recorded a Foot Function Index of 22 per cent. "residual lateral metatarsalgia, FFI 22%"
- 22 Jun 2013 — During warlike service in Afghanistan, while running about 80 metres under load to a waiting helicopter carrying about 35 kg, the veteran stepped into a concealed irrigation ditch and his left foot was forced violently into inversion and plantarflexion as he pushed off. He had immediate severe pain and swelling at the outer border of the foot and could not weight bear. The role 2 medical officer recorded marked tenderness over the fifth tarsometatarsal joint and the peroneus brevis insertion and painful, weak resisted eversion. X-ray showed no fracture. He was placed in a moon boot for two weeks. "re-injury L lateral foot, moon boot"
- 30 Jul 2013 — After return to Australia, MRI showed a high-grade partial tear of the dorsal ligaments of the left fifth tarsometatarsal joint and a longitudinal split tear of the distal peroneus brevis tendon extending to its insertion, with increased bone marrow oedema at the base of the fifth metatarsal. The Foot Function Index had risen to 58 per cent and pain was 7 out of 10. Stress views showed no instability. He was referred to an orthopaedic foot and ankle surgeon. "split tear PB, FFI 58%"
- 18 Mar 2014 — An orthopaedic foot and ankle surgeon performed debridement and tubularised repair of the left peroneus brevis tendon. He was in a cast for six weeks. Lateral forefoot pain persisted and he was medically downgraded from infantry duties in 2015. "peroneus brevis repair"
Symptoms
At onset the veteran had sudden tearing pain on the outer border of the left foot with swelling and bruising over the base of the fifth metatarsal, difficulty weight bearing and pain on turning the foot outwards. After the initial injury he developed aching under the lateral forefoot and the base of the fifth metatarsal after patrols, runs and prolonged standing, and he walked on the inner border of the foot.
After the 2013 worsening the pain became constant, with swelling after activity, weakness pushing off and difficulty walking on uneven ground. He now cannot run, walks with a limp after more than 30 minutes, has pain wearing firm boots and needs custom orthoses in all footwear.
Imaging
- 19 Jul 2009 — X-ray left foot: "No fracture of the base of the fifth metatarsal or the tarsal bones. Soft tissue swelling over the lateral midfoot."
- 15 Jan 2010 — MRI left foot: "Sprain of the dorsal and plantar ligaments of the fifth tarsometatarsal joint with bone marrow oedema at the base of the fifth metatarsal. Thickening and partial tearing of the peroneus brevis tendon at its insertion. No fracture."
- 22 Jun 2013 — X-ray left foot: "No fracture. Soft tissue swelling over the base of the fifth metatarsal."
- 30 Jul 2013 — MRI left foot: "High-grade partial tear of the dorsal ligaments of the fifth tarsometatarsal joint. Longitudinal split tear of the distal peroneus brevis tendon extending to its insertion. Increased bone marrow oedema at the base of the fifth metatarsal. Joint alignment maintained."
Onset Date
The most likely date of onset of this condition is 18 Jul 2009.
At that date the veteran was serving on warlike service in Afghanistan as an infantry rifleman on dismounted patrols. On 18 July 2009 he jumped down from a 1.8 metre compound wall carrying about 40 kg and landed on a rock with his left foot plantarflexed and forced into inversion, with immediate pain, swelling and bruising on the outer border of the foot.
This date is appropriate because his pre-deployment medical examination of 02 March 2009 recorded normal feet and ankles with no previous foot injury, and he presented to the patrol base medic with pain and tenderness on the same evening, well within the 24 hours after the injury required by the Statement of Principles definitions of sprain and strain. It falls within uninterrupted full-time warlike service.
The onset factors set no period before onset: they require the force, and the forceful stretching or high intensity use, to occur at the time of the clinical onset. Both occurred at one moment on 18 Jul 2009, when the landing applied a significant inversion force through the fifth tarsometatarsal joint and forcefully stretched the contracting peroneus brevis tendon. The definitions require pain and tenderness at the site within the 24 hours after the injury, which runs from 18 Jul 2009 to 19 Jul 2009; pain was immediate and tenderness was recorded the same evening and on X-ray the next day.
For the worsening factors, the sprain and strain were established and documented from July 2009 and confirmed on MRI on 15 Jan 2010, with residual metatarsalgia recorded on 10 Sep 2010. The clinical worsening occurred on 22 Jun 2013 in Afghanistan, when the foot was forced into inversion as he pushed off running under load. The worsening factors also require the force and the forceful stretching to be present at the time of the worsening, which was that moment, and the worsening is confirmed by MRI on 30 Jul 2013 and a rise in the Foot Function Index from 22 to 58 per cent. Appropriate clinical management could not be obtained in Afghanistan from July to November 2009.
1. What is the formal diagnosis of the condition claimed above?
The formal diagnosis is Left Foot - Fifth Metatarsal Strain (Metatarsalgia): a strain of the peroneus brevis tendon at its insertion into the base of the left fifth metatarsal with an associated sprain of the left fifth tarsometatarsal joint ligaments, causing lateral metatarsalgia (ICD-10-AM S93.6), under the Statements of Principles concerning sprain and strain, Balance of Probabilities No. 28 of 2020 and Reasonable Hypothesis No. 27 of 2020.
A strain is an injury involving the tearing or stretching of a muscle or tendon, and a sprain is an injury involving the tearing or stretching of a joint ligament, each with pain and tenderness at the site within 24 hours of the injury. The peroneus brevis tendon runs behind the outer ankle bone and inserts into the base of the fifth metatarsal. It everts the foot and resists sudden inversion, so a forced inversion injury under load can both tear the ligaments of the fifth tarsometatarsal joint and forcefully stretch the contracting tendon at its insertion. Persisting injury of these structures causes pain at the base of the fifth metatarsal and along the lateral forefoot, which is described clinically as lateral metatarsalgia, and altered weight bearing that loads the lateral forefoot further.
In this veteran the injury occurred on 18 July 2009 during warlike service in Afghanistan, was confirmed on MRI in January 2010, and worsened on 22 June 2013 in a second inversion injury in Afghanistan.
2. For each diagnosis identified, please also provide the following dates:
When did the veteran first experience symptoms attributable to this condition?
18 July 2009.
When did the veteran first present to a health / medical provider for this condition?
18 July 2009.
When was the condition confirmed / formally diagnosed?
15 January 2010.
When did the veteran first present to you (or your practice) for this condition?
09 April 2025.
3. How was this diagnosis confirmed? i.e. what were the key symptoms and signs, investigation results, specialist opinions?
The diagnosis was made by a sports physician on 15 January 2010 on the history of a forced inversion injury under load, immediate pain and tenderness at the fifth tarsometatarsal joint and the peroneus brevis insertion, pain on resisted eversion and passive inversion, and MRI showing a sprain of the fifth tarsometatarsal joint ligaments and thickening with partial tearing of the peroneus brevis tendon at its insertion. A fracture of the base of the fifth metatarsal was excluded on X-ray on 19 July 2009 and MRI. This meets the Statement of Principles definitions of strain and sprain: tearing or stretching of a tendon and of joint ligaments, with pain and tenderness at the site within 24 hours of the injury.
The joint was stable on stress testing in 2010 and 2013, so the 2013 episode was not a recurrent sprain due to joint instability, which the definition excludes, but a fresh discrete injury that worsened the established sprain and strain. MRI on 30 July 2013 confirmed progression to a high-grade partial ligament tear and a longitudinal split tear of peroneus brevis, and the operative findings on 18 March 2014 confirmed the tendon tear.
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 18 July 2009, after 1 July 2004, during continuous full-time service. 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. The Reasonable Hypothesis instrument applies to the veteran's warlike service in Afghanistan in 2009, where the injury occurred, and in 2013, where it worsened.
The sprain and strain occurred in the same injury, so the sprain factors are applied to the fifth tarsometatarsal joint ligaments and the strain factors to the peroneus brevis tendon. 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 18 July 2009 the veteran jumped down from a 1.8 metre compound wall carrying about 40 kg and landed on a rock with the left foot plantarflexed and inverted. The combined body weight and load, landing from that height onto an uneven surface, applied a significant physical force through the left fifth tarsometatarsal joint, tearing its dorsal and plantar ligaments as shown on MRI on 15 January 2010. Pain and tenderness at the joint were recorded the same evening. The jump was made on a patrol in the course of his duties.
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 on 18 July 2009 the peroneus brevis contracted at high intensity to resist the sudden inversion of the loaded foot while the tendon was being forcefully stretched, producing tearing at its insertion into the base of the fifth metatarsal, confirmed on MRI on 15 January 2010. Tenderness at the insertion and pain on resisted eversion were recorded the same evening. The injury occurred while he was performing his duties.
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 22 June 2013, running under a 35 kg load, the veteran stepped into a concealed irrigation ditch and his left foot was forced violently into inversion and plantarflexion, applying a significant force through the already injured fifth tarsometatarsal joint. MRI on 30 July 2013 showed progression to a high-grade partial tear of the dorsal ligaments, and the Foot Function Index rose from 22 to 58 per cent. The joint remained stable, so this was a worsening of the sprain and not a recurrent sprain from instability. It occurred in the course of his duties.
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
- At the moment of the 22 June 2013 injury the veteran was pushing off at a sprint under load, with the peroneus brevis contracting at high intensity, and the forced inversion stretched the contracting tendon. MRI on 30 July 2013 showed a new longitudinal split tear of the distal peroneus brevis extending to its insertion, a worsening of the 2009 strain, later confirmed at surgery on 18 March 2014.
Factor 9(5): inability to obtain appropriate clinical management for sprain or strain. — MET
- After the 2009 injury the veteran could not be rested or rehabilitated: there was no physiotherapist in the area of operations, no replacement in his section and no MRI, so he continued patrolling with 40 kg on a taped foot from 18 July 2009 to 20 November 2009. Definitive imaging and rehabilitation began only after his return, six months after the injury, and the residual metatarsalgia followed. 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 a 1.8 metre compound wall with a 40 kg load onto a rock, on a dismounted patrol during warlike service in Afghanistan on 18 July 2009, applied a significant inversion force through the left fifth tarsometatarsal joint and sprained its ligaments, with pain and tenderness recorded the same evening.
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 during warlike service in Afghanistan on 18 July 2009 the contracting peroneus brevis was forcefully stretched as the loaded foot inverted, straining the tendon at its insertion into the base of the fifth metatarsal, with tenderness and pain on resisted eversion recorded the same evening.
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
- During warlike service in Afghanistan on 22 June 2013 the veteran's left foot was forced into inversion and plantarflexion in a concealed ditch as he ran under a 35 kg load to a helicopter, applying a significant force through the fifth tarsometatarsal joint and worsening the sprain, confirmed on MRI on 30 July 2013.
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 same incident on warlike service on 22 June 2013 the peroneus brevis was contracting at high intensity during a loaded sprint and was forcefully stretched by the inversion, producing a split tear of the tendon that worsened the 2009 strain.
Factor 9(5): inability to obtain appropriate clinical management for sprain or strain. — MET
- During warlike service in Afghanistan from July to November 2009 there was no physiotherapy, imaging beyond plain X-ray or relief from patrolling, and the veteran continued dismounted patrols under load on a taped, injured foot for four months before he could obtain rehabilitation.
The % contribution of the causes is 100% and significant.
Sequelae
The left lateral foot injury has caused a chronic antalgic gait, with the veteran walking on the inner border of the foot. This has led to left medial knee pain and right foot pain from overloading, and he has reduced capacity for walking and exercise. These are sequelae of the accepted condition and should be considered in any related claim.
Unintended Consequence
Met. Persisting pain and weakness after the peroneus brevis repair of 18 March 2014, including a tender scar and sural nerve irritation, is an unintended consequence of surgery performed and paid for by Defence while the veteran was serving (section 6A of the DRCA and the equivalent provisions of the MRCA).
Inability to Attain Appropriate Medical Management
MET. After the injury of 18 July 2009, during warlike service in Afghanistan, the veteran's sprain and strain could not be appropriately managed. There was no physiotherapist in the area of operations, MRI was not available and there was no replacement in his section, so he continued dismounted patrols carrying 40 kg on a taped foot for four months. Definitive diagnosis and rehabilitation began only after his return, six months after the injury, by which time he had developed lateral metatarsalgia from offloading. Applying the objective and subjective tests in Brew v Repatriation Commission (Full Federal Court, 10 September 1999, Merkel J), operational constraints that prevent rest, imaging and rehabilitation amount to an inability to obtain appropriate clinical management.
5. Please provide a Health Summary and a medication / prescribing history.
See attached report.
References
- 02 Mar 2009, Pre-deployment medical examination, Medical Officer, Garrison health centre
- 18 Jul 2009, Patrol base treatment record, Medical Officer, Afghanistan
- 19 Jul 2009, X-ray left foot, Role 2 medical facility, Afghanistan
- 21 Aug 2009, Patrol base treatment record, Medical Officer, Afghanistan
- 15 Jan 2010, MRI left foot, Radiologist
- 15 Jan 2010, Sports medicine consultation, Sports physician
- 10 Sep 2010, Podiatry assessment, Podiatrist
- 22 Jun 2013, Role 2 medical facility record and X-ray, Medical Officer, Afghanistan
- 30 Jul 2013, MRI left foot, Radiologist
- 18 Mar 2014, 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
