Diagnostic Assessment — Bilateral Feet - Pes Cavus
Example 1 of 1 · fictitious patient (Veteran BR)
Diagnostic Assessment
Bilateral Feet - Pes Cavus
No Statement of Principles applies to this condition (non-SOP claim).
ADF History
Veteran BR, date of birth 30 September 1975, Australian Army, Parachute Rifleman (Infantry), enlisted 07 February 1994, medically discharged 12 December 2014. Operational service: East Timor, 20 September 1999 to 18 February 2000 (warlike); Afghanistan, 03 March 2008 to 26 July 2008 (warlike, returned early after injury).
Occupational History
As a parachute rifleman the veteran completed frequent static-line parachute descents with equipment loads of up to 45 kilograms, including night and tactical descents onto rough drop zones, and long loaded foot patrols in rigid combat boots. He also travelled in protected vehicles exposed to improvised explosive device blast and fire.
Parachute infantry have high rates of foot and ankle fracture, lumbar disc injury and lower limb nerve injury from hard landings, and blast-exposed soldiers suffer crush injuries, compartment syndrome and burns of the lower limbs. The service culture of the period normalised heavy alcohol use after exercises and deployments.
History
Veteran BR, a parachute rifleman in the Australian Army, sustained bilateral talar neck fractures and a lumbosacral disc prolapse with cauda equina syndrome in a parachute landing in 2006, and crush injuries with bilateral compartment syndrome, a left common peroneal nerve injury and plantar burns in a blast in Afghanistan in July 2008. He developed bilateral acquired pes cavus with claw toes, first recorded on 15 April 2009, which worsened by 2012 with an alcohol-related polyneuropathy and a recurrent disc prolapse.
Timeline
- 11 Jun 2006 — During a peacetime night parachute descent with a 40 kg equipment load the veteran landed heavily on both feet on hard ground. CT showed bilateral displaced talar neck fractures, and he developed saddle anaesthesia and urinary retention from an L5-S1 disc prolapse causing cauda equina syndrome. He underwent emergency lumbar decompression and fixation of both talar fractures. "bilateral talar fractures, cauda equina"
- 19 Feb 2007 — Orthopaedic review showed healed talar neck fractures with mild varus malunion on CT, and residual weakness of ankle plantarflexion and toe flexion bilaterally (grade 4 of 5) from the S1 nerve roots, with reduced ankle reflexes. Foot arches were recorded as normal and he returned to full duties. "residual S1 weakness, arches normal"
- 14 Jan 2008 — At his pre-deployment medical both feet had normal medial longitudinal arches on standing, with no claw toes and a normal gait. He was cleared to deploy to Afghanistan. "arches normal, no claw toes"
- 22 Jul 2008 — On warlike service in Afghanistan an improvised explosive device struck the veteran's vehicle. His legs were pinned under the buckled floor for 40 minutes while a fire burned in the footwell. At the role 3 hospital he had bilateral crush injuries of the legs with acute compartment syndrome of the deep posterior compartments requiring four-compartment fasciotomies, a left fibular neck fracture with a complete left common peroneal nerve palsy, and deep partial thickness burns of both soles. "bilateral compartment syndrome, fasciotomies"
- 26 Jul 2008 — He was aeromedically evacuated to Australia. Both legs were immobilised in plaster with the ankles held in plantarflexion to protect the skin grafts on his soles and fasciotomy wounds, and remained so for ten weeks, until 03 October 2008. "both feet in equinus casts"
- 15 Apr 2009 — The physiotherapist and rehabilitation physician recorded new high medial longitudinal arches in both feet on standing, clawing of all toes, hindfoot varus and lateral foot pain when walking. The deep posterior compartment muscles were firm and contracted, there was a left foot drop, and the plantar burn scars were tight. Weight-bearing radiographs confirmed bilateral pes cavus. "bilateral cavus, claw toes"
- 06 Mar 2012 — Nerve conduction studies showed a length-dependent sensorimotor polyneuropathy, attributed by the neurologist to alcohol use disorder that developed after his 2008 deployment, with intake of about 80 grams a day. MRI showed a recurrent L5-S1 disc prolapse compressing both S1 nerve roots. Weight-bearing radiographs showed worsening of the cavus deformity in both feet, and he developed callosities under the metatarsal heads and recurrent ankle sprains. "polyneuropathy, cavus worsening"
- 21 Aug 2012 — Custom orthoses and a podiatry and orthotics program recommended in 2009 had not been provided because of a prolonged referral backlog, and he had continued field training in standard rigid boots. An orthopaedic foot surgeon confirmed progressive bilateral cavovarus deformity and recommended plantar fascia release and tendon transfer. He was medically discharged in 2014. "progressive cavovarus, orthoses delayed"
Symptoms
At onset the veteran had a noticeable rise in the arches of both feet, clawing of the toes, pain along the outer borders of his feet and under the balls of his feet when walking, difficulty fitting into his boots and a tendency to roll his ankles on uneven ground. After onset the deformity became more rigid and painful callosities formed under the metatarsal heads.
Since the worsening in 2012 he has had constant foot pain after walking more than 500 metres, recurrent ankle sprains, numbness and burning in both feet, toe ulceration risk from rubbing of the clawed toes, and difficulty standing for long periods. He needs custom footwear.
Imaging
- 11 Jun 2006 — CT both ankles: "Displaced fractures of the necks of both tali."
- 19 Feb 2007 — CT both ankles: "Healed talar neck fractures with mild varus malunion bilaterally. No avascular necrosis."
- 15 Apr 2009 — Weight-bearing radiographs both feet: "Bilateral pes cavus. Lateral talo-first metatarsal (Meary) angle 12 degrees apex dorsal on the right and 14 degrees on the left. Calcaneal pitch 33 degrees right and 34 degrees left. Clawing of the toes."
- 06 Mar 2012 — Weight-bearing radiographs both feet: "Progression of bilateral cavus: Meary angle 21 degrees right and 24 degrees left, calcaneal pitch 38 degrees right and 39 degrees left. Increased hindfoot varus."
- 06 Mar 2012 — MRI lumbar spine: "Recurrent L5-S1 disc prolapse compressing both S1 nerve roots at the site of the previous decompression."
Onset Date
The most likely date of onset of this condition is 15 Apr 2009.
At that date the veteran was serving full time with a parachute infantry battalion in Australia, on restricted duties and in rehabilitation after the blast injuries he sustained on warlike service in Afghanistan on 22 July 2008. The physiotherapist and rehabilitation physician recorded new high arches, claw toes and hindfoot varus in both feet, confirmed the same day on weight-bearing radiographs.
This date is appropriate because his pre-deployment medical of 14 January 2008 recorded normal arches with no claw toes, his legs were then in plaster until 03 October 2008, and the deformity was first recorded and confirmed on 15 April 2009. It falls within uninterrupted full-time service.
Each recognised cause relied on was established before onset: the talar neck fractures and the cauda equina lesion on 11 Jun 2006, with residual S1 weakness documented on 19 Feb 2007; and the compartment syndrome, the left common peroneal nerve injury and the plantar burns on 22 Jul 2008. For the immobilisation cause, the period of at least 6 weeks before onset was filled by ten weeks in plantarflexed casts from 26 Jul 2008 to 03 Oct 2008, which ended six months before onset.
For the worsening causes, the documented worsening was on 06 Mar 2012, when weight-bearing radiographs showed the Meary angle increased from 12 to 21 degrees on the right and from 14 to 24 degrees on the left. The polyneuropathy and the recurrent L5-S1 disc prolapse were both present on that date, and orthoses recommended in 2009 had not been provided in the three years between onset and the worsening.
1. What is the formal diagnosis of the condition claimed above?
The formal diagnosis is Bilateral Feet - Pes Cavus (ICD-10-AM M21.6, other acquired deformities of the ankle and foot), an acquired bilateral cavovarus foot deformity with claw toes. No Statement of Principles has been determined for pes cavus.
Pes cavus is a foot deformity with an abnormally high medial longitudinal arch, usually with hindfoot varus, plantarflexion of the first ray and clawing of the toes. Acquired pes cavus results from an imbalance between the muscles that control the foot, from contracture of the soft tissues of the leg and sole, or from malunion of the hindfoot bones. Neurological causes include injury to the lumbosacral nerve roots and peripheral nerves and peripheral neuropathy, and musculoskeletal causes include ischaemic contracture after compartment syndrome, talar fracture malunion, burn contracture of the sole and prolonged immobilisation in equinus. The deformity concentrates load on the heel and metatarsal heads and predisposes to callosities, lateral ankle instability and stress fractures.
The deformity began after the veteran's 2006 and 2008 service injuries, was first recorded and confirmed on 15 April 2009, and worsened by March 2012.
2. For each diagnosis identified, please also provide the following dates:
When did the veteran first experience symptoms attributable to this condition?
15 April 2009.
When did the veteran first present to a health / medical provider for this condition?
15 April 2009.
When was the condition confirmed / formally diagnosed?
15 April 2009.
When did the veteran first present to you (or your practice) for this condition?
09 September 2025.
3. How was this diagnosis confirmed? i.e. what were the key symptoms and signs, investigation results, specialist opinions?
The diagnosis was confirmed clinically and radiologically on 15 April 2009. On standing both feet showed high medial longitudinal arches that did not flatten on weight-bearing, hindfoot varus and claw toes. Weight-bearing radiographs showed a Meary angle of 12 degrees on the right and 14 degrees on the left, apex dorsal, and a calcaneal pitch above 30 degrees bilaterally, which are diagnostic of pes cavus. The deformity was new: his arches were normal on 14 January 2008.
Examination identified the drivers of the deformity: contracture of the deep posterior compartment muscles after compartment syndrome, a left foot drop from common peroneal nerve palsy, bilateral S1 weakness and tight plantar burn scars. Hereditary neuropathy was excluded by the history of normal arches and on neurological assessment. An orthopaedic foot surgeon confirmed progressive bilateral cavovarus deformity on 21 August 2012, with radiographic progression on 06 March 2012.
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.
No Statement of Principles has been determined for pes cavus. The claim is therefore decided on the sound medical-scientific evidence of what causes the condition and on whether, on that evidence, the condition is related to the veteran's service, without the limits of a Statement of Principles. The recognised causes below are drawn from the orthopaedic and neurological literature on acquired pes cavus and are set out in the style of Statement of Principles factors.
Legislation: the clinical onset of this condition was on 15 April 2009, after 1 July 2004, during continuous full-time service. This is a Military Rehabilitation and Compensation Act 2004 (MRCA) claim. The veteran's warlike service in Afghanistan in 2008, where the blast, compartment syndrome, nerve injury and burns occurred, and his peacetime service, where the parachute landing injuries occurred in 2006, are each relevant service. Each cause must be related to that 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.
Recognised causes on the medical-scientific evidence (no Statement of Principles)
Causative factors
Cause 1: having a fracture of the talus, calcaneus or midfoot of the affected foot, with malunion, before the clinical onset of pes cavus; — MET
- The veteran sustained displaced fractures of both talar necks in a heavy landing on a peacetime night parachute descent with a 40 kg load on 11 June 2006. CT on 19 February 2007 showed both had healed with varus malunion, which tilts the hindfoot into varus and raises the arch. The malunion was present in both feet before onset on 15 April 2009.
Cause 2: having a lesion of the cauda equina or of the lumbosacral nerve roots supplying the affected foot, with weakness of the muscles of the leg or foot, before the clinical onset of pes cavus; — MET
- The parachute landing of 11 June 2006 caused an L5-S1 disc prolapse with cauda equina syndrome requiring emergency decompression. Residual bilateral S1 weakness of ankle plantarflexion and toe flexion, with reduced ankle reflexes, was documented on 19 February 2007 and persisted to onset. Weakness of the intrinsic foot muscles and calf leads to clawing of the toes and elevation of the arch.
Cause 3: having acute compartment syndrome of the leg on the affected side, resulting in ischaemic contracture of the leg muscles, before the clinical onset of pes cavus; — MET
- On warlike service in Afghanistan on 22 July 2008 the veteran's legs were crushed under his vehicle's buckled floor for 40 minutes and he developed acute compartment syndrome of both deep posterior compartments, requiring fasciotomies at the role 3 hospital. On 15 April 2009 the deep posterior compartment muscles were firm and contracted, producing the claw toes and cavovarus posture typical of ischaemic contracture.
Cause 4: having an injury to the common peroneal, deep peroneal or tibial nerve of the affected limb before the clinical onset of pes cavus; — MET
- The blast of 22 July 2008 fractured the left fibular neck and caused a complete left common peroneal nerve palsy, documented at the role 3 hospital and with foot drop persisting on 15 April 2009. Loss of the ankle dorsiflexors and peroneus brevis leaves the tibialis posterior and peroneus longus unopposed, driving the forefoot into plantarflexion and the hindfoot into varus.
Cause 5: having a burn or crush injury of the sole of the affected foot, resulting in contracture of the plantar soft tissues, before the clinical onset of pes cavus; — MET
- The fire in the vehicle footwell on 22 July 2008 caused deep partial thickness burns of both soles, which were grafted, and the soles were crushed under the vehicle floor. The plantar scars were recorded as tight on 15 April 2009, tethering the plantar fascia and pulling the forefoot towards the heel.
Cause 6: being immobilised with the affected foot held in plantarflexion for a continuous period of at least 6 weeks before the clinical onset of pes cavus; — MET
- After evacuation on 26 July 2008 both legs were immobilised in plaster with the ankles held in plantarflexion for ten weeks, to 03 October 2008, to protect the plantar grafts and fasciotomy wounds. This caused shortening of the calf and plantar structures in both feet before onset on 15 April 2009.
Worsening factors
Worsening 1: having peripheral neuropathy affecting the affected foot at the time of the clinical worsening of pes cavus; — MET
- Nerve conduction studies on 06 March 2012 showed a length-dependent sensorimotor polyneuropathy affecting both feet, which the neurologist attributed to alcohol use disorder that developed after the veteran's warlike service in Afghanistan and his blast injuries. The polyneuropathy weakened the intrinsic foot muscles and was present when radiographs the same day showed the cavus had worsened.
Worsening 2: having compression of the lumbosacral nerve roots supplying the affected foot at the time of the clinical worsening of pes cavus; — MET
- MRI on 06 March 2012 showed a recurrent L5-S1 disc prolapse compressing both S1 nerve roots at the site of the decompression performed for his 2006 service injury. The root compression was present at the documented worsening, when the Meary angle had increased from 12 to 21 degrees on the right and from 14 to 24 degrees on the left.
Worsening 3: inability to obtain appropriate clinical management for pes cavus. — MET
- Custom orthoses, podiatry and an orthotics program were recommended at diagnosis in April 2009 but were not provided for more than three years because of a referral backlog, and the veteran continued field training in standard rigid boots. The deformity progressed, with radiographic worsening by 06 March 2012 and a recommendation for surgery in August 2012. Under Brew v Repatriation Commission (1999) this is an inability to obtain appropriate clinical management.
The % contribution of the causes is 100% and significant.
Sequelae
The bilateral pes cavus is a sequela of the veteran's accepted injuries: the bilateral talar neck fractures and the lumbosacral disc prolapse with cauda equina syndrome from the 2006 parachute landing, and the bilateral compartment syndrome, left common peroneal nerve palsy and plantar burns from the 2008 blast. The metatarsalgia, callosities, claw toes and recurrent lateral ankle sprains are in turn sequelae of the pes cavus.
Unintended Consequence
Met. The ten weeks of immobilisation of both feet in plantarflexion, a necessary part of the Defence-provided treatment of his plantar grafts and fasciotomy wounds, shortened the calf and plantar soft tissues and contributed to the cavus deformity. This is an unintended consequence of treatment provided by the Commonwealth (section 6A of the DRCA and the equivalent provisions of the MRCA).
Inability to Attain Appropriate Medical Management
MET. At diagnosis in April 2009 the veteran was recommended custom orthoses, podiatry and an orthotics program, but these were not provided for more than three years because of a referral backlog, and he continued field training in standard rigid military boots. During this period the deformity became more rigid and progressed, with the Meary angle increasing by 9 to 10 degrees in each foot by 06 March 2012, and surgery was then recommended. Applying the objective and subjective tests in Brew v Repatriation Commission (Full Federal Court, 10 September 1999, Merkel J), a delay of this length in providing recognised treatment amounts to an inability to obtain appropriate clinical management.
5. Please provide a Health Summary and a medication / prescribing history.
See attached report.
References
- 11 Jun 2006, Trauma admission, CT and operation reports, Orthopaedic surgeon and Neurosurgeon
- 19 Feb 2007, Orthopaedic review and CT both ankles, Orthopaedic surgeon
- 14 Jan 2008, Pre-deployment medical, Medical Officer
- 22 Jul 2008, Trauma admission and operation reports, Role 3 hospital, Afghanistan
- 26 Jul 2008, Aeromedical evacuation summary and burns unit admission, Burns surgeon
- 15 Apr 2009, Rehabilitation assessment and weight-bearing radiographs, Rehabilitation physician and Physiotherapist
- 06 Mar 2012, Nerve conduction studies and neurology consultation, Neurologist
- 06 Mar 2012, Weight-bearing radiographs both feet and MRI lumbar spine, Radiologist
- 21 Aug 2012, Specialist consultation, Orthopaedic foot and ankle surgeon
- Medical-scientific literature on the causes of acquired pes cavus (no Statement of Principles determined)
