Statement of Principles concerning joint instability (Reasonable Hypothesis) (No. 57 of 2019)

The central concept is joint instability as defined in subsection 7(2). It means an acquired lack of stability of a joint due to damage to or abnormality of the stabilising structures of that joint, manifesting as recurrent subluxation, recurrent dislocation, or recurrent sprain. The definition expressly includes joints with an internal joint prosthesis, but it excludes spondylolisthesis and the loosening or migration of the fixation component of an internal joint prosthesis. This exclusion is significant: a veteran with a failed hip replacement due to prosthesis loosening cannot rely on this SoP to claim joint instability unless the loosening is a separate condition, and the claim would then need to be assessed under a different SoP (likely the one on loosening of prosthesis or the underlying joint disease). The SoP also lists specific ICD‑10‑AM codes (M22.0, M22.1, M23.5, M24.2, M24.4, M25.3, M43.3, M43.4, M43.5, M53.2, T84.0) but states that the meaning of joint instability is that given in the definition, not the code. This prevents a simple coding match from overriding the clinical definition.

The concept of “relevant service” is defined in the dictionary by reference to the VEA and the MRCA. It covers operational service, peacekeeping service, hazardous service, and British nuclear test defence service under the VEA, as well as warlike service and non‑warlike service under the MRCA. This means the SoP applies to a broad range of service types but not to peacetime service under the VEA that is not operational, peacekeeping, hazardous, or British nuclear test defence service. For those other service types, a different standard under the VEA may apply, but the SoP is not directly applicable.

Another key concept is the distinction between clinical onset and clinical worsening. The SoP provides separate factor lists for each. For onset, factors (1) to (13) apply; for worsening, factors (14) to (24) apply. Factor (25) - inability to obtain appropriate clinical management - applies to both onset and worsening, but only if that inability contributed to the development or worsening of the condition. The “clinical worsening” factors are further qualified by section 10(2), which states that they apply only to material contribution to or aggravation of joint instability where the person’s joint instability was suffered or contracted before or during (but did not arise out of) the person’s relevant service. This addresses veterans who entered service with a pre‑existing joint instability.

The concept of “disease process as specified” is defined broadly in the dictionary to include three categories: (a) neurological, neuromuscular or muscular conditions (including brain or spinal injuries with spasticity or flaccid paralysis, cerebrovascular accident, Parkinson’s disease, myasthenia gravis, poliomyelitis, drug‑induced dyskinesia, and peripheral neuropathy); (b) infective, inflammatory or degenerative conditions of the affected joint (including septic arthritis, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthropathy, crystal arthropathy, Grisel syndrome, and osteoarthritis); and (c) intra‑articular space‑occupying lesions (including neoplastic lesions such as sarcoma, osteosarcoma, chondrosarcoma, and pigmented villonodular synovitis). This definition captures a wide range of underlying pathologies that can destabilise a joint.

The concept of “soft tissue structure as specified” is narrower: it means a joint capsule, tendon, ligament, or fibrocartilaginous structure that contributes to joint stability in the affected joint. Damage to such a structure must occur before clinical onset or worsening. The examples given in the notes to the factors (e.g., falls, collisions, lifting weights, push ups, pull ups, throwing objects, seizure, electrical injury) are not exhaustive but illustrate the type of trauma that might satisfy factor (1) or (14).

Finally, the concept of “reasonable hypothesis” is not defined in this SoP but is a settled legal standard in veterans’ law. The SoP does not create the standard; it only specifies the medical factors that must be present to raise such a hypothesis. The Repatriation Medical Authority’s view in section 8 is that sound medical‑scientific evidence indicates that joint instability and death from joint instability can be related to relevant service. This is the basis for determining the factors, but it does not guarantee that any particular claim will succeed.

The SoP directly affects three groups: claimants, the Department of Veterans’ Affairs (including the Repatriation Commission), and the Veterans’ Review Board and Administrative Appeals Tribunal (AAT) when reviewing decisions. Claimants include veterans, members of the Peacekeeping Forces, members of the Forces under the VEA, and members under the MRCA who have rendered “relevant service” as defined in the dictionary. Their dependants may also be affected if a death claim is made. The SoP does not apply to members who rendered only peacetime service that is not classified as operational, peacekeeping, hazardous, or British nuclear test defence service under the VEA, nor to members under the MRCA who rendered non‑warlike service not within the definition. However, such persons may still claim under other provisions of the VEA or MRCA, but they cannot rely on this SoP.

Medical practitioners who provide reports for veterans’ claims are indirectly affected because their opinions must now address the specific factors listed in section 9. A medical report that merely states “the joint instability is due to service trauma” may be insufficient unless it identifies a factor such as physical trauma to the affected joint at the time of clinical onset, or a dislocation, sprain, soft tissue damage, fracture, or disease process as specified. If the claim involves a joint‑specific factor (e.g., temporomandibular joint instability from wide mouth opening, or hip prosthesis instability from lumbar spine conditions), the medical report must address those particulars. The SoP therefore imposes a compliance burden on medical experts who may not be familiar with the precise wording of the factors.

Legal practitioners and advocates representing claimants must be familiar with the SoP to frame their submissions. They need to identify which factor(s) apply and ensure the medical evidence matches the definition. For example, if a claimant has recurrent sprains of the ankle from marching during service, the advocate must show that the sprain was a manifestation of joint instability (i.e., lack of stability due to damage to stabilising structures) and not merely an acute sprain that healed. The distinction between an ordinary sprain and recurrent sprain as a symptom of joint instability is critical.

The Department of Veterans’ Affairs (DVA) delegates and decision‑makers must apply the SoP when assessing claims. This reduces their discretion but also provides a checklist: if medical evidence establishes at least one factor and the factor is related to relevant service, the claim must succeed unless the evidence is not accepted as sound medical‑scientific evidence (which is unlikely given the SoP is itself based on such evidence). The SoP also affects the DVA’s guidelines for processing claims and may lead to more standardised outcomes.

Finally, the Repatriation Medical Authority itself is affected in that it must periodically review and update SoPs. This SoP repealed the 2010 version, and future amendments may alter the factor lists, potentially broadening or narrowing them as medical science evolves.

The SoP does not impose direct duties or confer rights in the way a statute would. Instead, it operates as a factual gateway within the existing claim‑assessment framework. The key right it grants to claimants is the ability to raise a reasonable hypothesis by proving at least one of the specified factors. Conversely, it imposes a duty on decision‑makers to accept that a reasonable hypothesis exists if the factual prerequisites are met. However, the SoP also sets boundary conditions: factors must be related to relevant service (section 10(1)), and factors for clinical worsening apply only when the condition was pre‑existing and did not arise out of service (section 10(2)). Claimants have no right to rely on factors not listed; if their medical condition does not match any factor, the claim will fail regardless of other medical opinion.

The right to have the SoP applied correctly is enforceable through the review process. If a decision‑maker misapplies the SoP, the claimant can seek review by the Veterans’ Review Board and then the AAT. The tribunal must give effect to the SoP as a legislative instrument. Claimants also have the right to submit medical evidence that addresses the definitions in Schedule 1, such as BMI calculations for obesity factors, or specialist diagnoses of disease processes. Claimants do not have a right to have the SoP disregarded on the basis of alternative medical theories; the Repatriation Medical Authority’s determination of sound medical‑scientific evidence is binding.

The duty on the Department is to consider the SoP before making a decision. This includes correctly identifying the relevant factor, ensuring the factor is related to service (applying the standard of reasonable hypothesis), and not substituting its own view of what constitutes joint instability. The duty also extends to applying the cross‑reference mechanism in section 11: if a factor refers to a condition covered by another SoP (e.g., soft tissue damage may trigger the SoP on ligament injury), the decision‑maker must apply that other SoP as well.

The SoP also creates a duty on medical experts to provide reports that are consistent with the definitions. For instance, a report stating “the patient has a BMI of 32, therefore is obese” must be precise about the timing: the obesity must exist at the time of clinical onset or worsening for the hip prosthesis or tibiofemoral factors. A report that does not specify timing may be insufficient.

Importantly, the SoP does not create a right to claim joint instability as a separate condition if the claimant already has an accepted diagnosis of, say, osteoarthritis. The osteoarthritis may be the underlying disease process causing instability, but the claim must be for joint instability itself (or death from it). Claimants have the right to seek a diagnosis of joint instability that fits the definition, not just any joint pain or stiffness.

The SoP itself does not contain penalty provisions; it is a medical‑scientific instrument that governs the evaluation of claims. Enforcement of the SoP is indirect, through the review and appeal mechanisms under the VEA and MRCA. If a decision‑maker fails to apply the SoP correctly, a claimant can appeal. The Veterans’ Review Board and the AAT can set aside the decision and remit it with directions to apply the SoP. There is no monetary penalty for non‑compliance by decision‑makers, but systemic failure to apply SoPs could lead to judicial review in the Federal Court.

Penalties under the VEA and MRCA for making false or misleading statements in support of a claim (such as fabricating a trauma or misrepresenting BMI) remain in force. These are criminal offences carrying imprisonment and fines. For example, under section 141 of the VEA (as in force at the time of the SoP), a person who makes a false statement to obtain a pension may be liable to imprisonment for 12 months. The SoP does not alter those penalties.

For practitioners, the professional consequences of misapplying the SoP may include adverse costs orders in tribunal proceedings or complaints to professional bodies, but the SoP itself does not prescribe sanctions. The main enforcement pressure comes from the requirement that claims be determined in accordance with law; failure to consider the SoP is a legal error that will invalidate the decision.

The SoP also indirectly enforces medical consistency. Because it is binding, medical practitioners who provide reports that conflict with the definitions (e.g., diagnosing joint instability without the required recurrent subluxation, dislocation, or sprain) may see their reports rejected. This does not carry a penalty for the doctor, but it can disadvantage the claimant and lead to adverse credibility findings. Over time, the SoP shapes medical practice in veterans’ health.

The SoP is made under the VEA but also applies to claims under the MRCA. It interacts with the primary legislation by specifying the medical criteria for the reasonable hypothesis standard. Section 120A of the VEA and section 338 of the MRCA require that for any claim in which a SoP exists, the claim must be assessed by reference to that SoP. This SoP therefore displaces any alternative medical‑scientific evidence that might otherwise be considered. It is a form of statutory override: even if a doctor believes that a different mechanism caused joint instability, only the listed factors are legally relevant.

The SoP also interacts with other Statements of Principles. Section 11 provides that if a factor refers to an injury or disease covered by another SoP (e.g., “having a fracture” might trigger the SoP on fracture), then the factors in that other SoP apply. This creates a network of interlocking instruments. A decision‑maker may need to consult multiple SoPs for a single factor. For example, if a claimant has joint instability due to rheumatoid arthritis, factor (6) (disease process as specified) may apply; but if the rheumatoid arthritis is itself claimed as a separate condition, its own SoP (if any) would govern that part of the claim. The interaction is hierarchical: the SoP for joint instability is the primary instrument, but it incorporates other SoPs by reference.

The SoP also interacts with the common law of reasonable hypothesis, which is the standard set by the High Court in Repatriation Commission v Deledio (1998) and subsequent cases. The SoP does not codify that standard; it only provides the medical content. The legal test of whether a hypothesis is reasonable continues to be applied by tribunals, with the SoP acting as a necessary (but not sufficient) condition. In practice, once a factor is established and related to service, the hypothesis is deemed reasonable.

The definition of “relevant service” ties the SoP to the definitions in the VEA and MRCA. If those definitions change (e.g., if new types of service are added), the SoP automatically applies to them without amendment, because the dictionary definition of “relevant service” is dynamic (it refers to the definitions in the Acts). The SoP also interacts with the Guide to the Assessment of Rates of Veterans’ Pensions (GARP), which is used to assess impairment. The SoP does not affect the rating, but it affects acceptance of liability.

The SoP repeals and replaces the earlier Statement of Principles concerning joint instability No. 32 of 2010 (Federal Register of Legislation No. F2010L01048). That earlier instrument was made under the same legislative power (subsection 196B(2) of the VEA) and contained a similar structure of factors. The current instrument does not specify what changes were made from the 2010 version, but likely updates reflect new medical evidence or clarifications of definitions. For example, the current SoP includes specific references to ICD‑10‑AM Edition 2017, whereas the 2010 version may have referred to an earlier edition. The current SoP also includes explicit references to Grisel syndrome in the definition of disease process as specified, which may be a addition. The pregnancy factor (six weeks before onset/worsening) and the various obesity‑related factors for specific prostheses appear to be carried over from 2010 or refined.

The SoP was made on 26 April 2019 and commenced on 27 May 2019. It is not subject to automatic sunsetting under the Legislation Act 2003 (as a legislative instrument made by the Repatriation Medical Authority, it may be subject to review but not a fixed 10‑year sunset). As of the text of the instrument, no subsequent amendments have been incorporated; the instrument is current. However, the Repatriation Medical Authority regularly reviews and issues new SoPs as medical science evolves, so future amendments or replacements are likely. The repeal of the 2010 SoP means that any claim for joint instability based on factors that existed only in the old SoP (and not in the new one) will fail, unless the claim was lodged before commencement and transitional provisions apply.

The SoP itself (No. 57 of 2019) has not been the subject of any reported litigation as of the date of this analysis, at least not that is disclosed in the instrument. It is a relatively recent instrument. However, its predecessor (No. 32 of 2010) would have been litigated in the AAT and possibly the Federal Court on questions of statutory interpretation, such as the meaning of “joint instability” or whether a particular factor was supported by sound medical‑scientific evidence. Those decisions may be persuasive in interpreting the current SoP, though caution is needed because the definitions and factors may have changed.

The highest‑profile litigation involving Statements of Principles generally concerns the reasonableness of the hypothesis and the relationship to service. For joint instability specifically, cases may have addressed the distinction between acute sprain and recurrent sprain as a manifestation of instability, or whether pregnancy alone (without other factors) is sufficient. Because the SoP provides a closed list of factors, litigation often turns on whether a particular set of facts fits within a factor. For example, a veteran claiming that heavy lifting caused knee instability would need to show that the lifting constituted “physical trauma to the affected joint at the time of the clinical onset” - the AAT may examine whether lifting weights (a listed example) is sufficient when the trauma is not a discrete event but cumulative.

The “disease process as specified” definition is likely to be litigated because it uses inclusive language (“including, but limited to”) which leaves room for argument about whether a particular condition falls within the categories. For instance, a claim based on Ehlers‑Danlos syndrome (a connective tissue disorder) might be argued to be a “neurological, neuromuscular or muscular condition” or “an infective, inflammatory or degenerative condition” - neither clearly fits. The AAT may need to decide if the definition is exhaustive or merely illustrative. The note in the definition for Grisel syndrome suggests that the Authority intended to catch unusual conditions, but that may invite creative arguments.

No specific cases are mentioned in the instrument, and we must not invent any. It is safe to say that the instrument has not been judicially considered, but the broader body of SoP case law applies.

Several provisions in the SoP are traps for the unwary. First, the definition of joint instability excludes spondylolisthesis and loosening or migration of the fixation component of an internal joint prosthesis. This means a veteran who has a spinal condition causing instability at the vertebral level cannot claim under this SoP; they must rely on a different SoP (if any) for spondylolisthesis. Likewise, a veteran with a loosened hip replacement cannot claim joint instability; the loosening itself is a separate condition. However, joint instability is defined to include joints with an internal joint prosthesis - so a well‑fixed prosthesis that becomes unstable due to soft tissue damage is covered. The trick is distinguishing between loosening of the fixation (excluded) and instability of the joint due to other causes (included).

Second, the factors for clinical worsening (paragraphs 9(14) to 9(24)) apply only if the person’s joint instability was suffered or contracted before or during (but did not arise out of) the person’s relevant service. This is a common feature of SoPs for aggravation, but it is easily overlooked. If a veteran had joint instability that manifest only after service, the worsening factors cannot be used; only the onset factors apply. The “did not arise out of” condition also means that if the instability itself was caused by service, the worsening factors are unnecessary because the whole condition is service‑related. But if the instability pre‑existed service and was worsened by service, the worsening factors must be shown.

Third, the pregnancy factor (paragraphs 9(7) and 9(18)) applies only to clinical onset or worsening of joint instability within six weeks of being pregnant. This is a very narrow window. Most pregnancy‑related joint laxity resolves after delivery, and if instability becomes chronic, the factor may not apply if the time gap is more than six weeks. The factor does not require the pregnancy to be related to service, only that the person was pregnant at the relevant time. This could be relevant for female veterans who became pregnant during service.

Fourth, the obesity factors are joint‑specific. For tibiofemoral joint instability, the claimant must be “severely obese” (BMI ≥ 35), not merely obese (BMI ≥ 30). For total knee prosthesis joint instability, the threshold is “morbid obesity” (which is not defined in this SoP - the dictionary only defines “obese” and “severely obese”; the term “morbid obesity” is used but not defined, which is a drafting oversight. The dictionary defines “being obese” as BMI ≥ 30 and “being severely obese” as BMI ≥ 35, but does not define “morbid obesity.” The factor in paragraph 9(12) refers to “morbid obesity” without definition. This may be a typographical error or an intended reference to the clinical definition (usually BMI ≥ 40), but it is ambiguous and could be litigated.

Fifth, the factor for elbow joint instability (paragraph 9(13)) requires “more than three local glucocorticoid injections for epicondylitis before the clinical onset of joint instability.” Note that it is “more than three” - so three injections exactly does not count. The timing is also critical: the injections must be before the clinical onset (not after). The link between epicondylitis injections and elbow instability is specific and may catch claimants who had injections for tennis elbow during service.

Sixth, the “disease process as specified” includes “intra‑articular space occupying lesion” with examples that include neoplastic lesions. But note that synovitis (pigmented villonodular synovitis) is included; other types of synovitis are not explicitly listed but may fall under the inflammatory category. The list is not exhaustive, but the term “including, but limited to” is ambiguous - likely meant “including, but not limited to” as used elsewhere. The draftsman omitted “not” before “limited.” This is a clear drafting error: the note says “including, but limited to” which is contradictory. In the text it says “including, but limited to” which might be interpreted as including only those listed. However, the note for Grisel syndrome says “Note: Grisel syndrome is atlantoaxial joint subluxation due to contiguous inflammation from the ear, nose or throat.” That note does not limit the category. This error could be exploited to argue that the list is exhaustive, but the better view is that it is a typo.

Seventh, the “soft tissue structure as specified” definition requires that the structure contributes to joint stability in the affected joint. This may exclude structures that do not contribute to stability (e.g., a tendon that crosses the joint but does not stabilise it). Medical evidence must establish the functional role.

Eighth, the factor “inability to obtain appropriate clinical management for joint instability” (paragraph 9(25)) applies to both onset and worsening. But it is open‑ended. The claimant must show that appropriate clinical management was not obtained and that this inability contributed to the joint instability. This does not require fault on the part of the military; it could arise from logistical issues during service (e.g., deployment to a remote area without orthopaedic care). However, the burden is on the claimant to prove that the management was appropriate and that the inability caused the onset or worsening. This is a high bar.

Ninth, the cross‑reference mechanism in section 11 can create circular references. If a factor refers to a disease process that is itself defined by another SoP, that SoP may in turn refer back to this SoP. In practice, the Authority avoids such loops, but practitioners should be alert.

Tenth, the dictionary defines “terminal event” for death claims. It includes pneumonia, respiratory failure, cardiac arrest, circulatory failure, and cessation of brain function. This list is exhaustive? The wording “includes the following” followed by a list suggests it is not exhaustive, but the list is closed. It likely means that death from joint instability requires that one of these terminal events was contributed to by joint instability. If death is entirely independent (e.g., suicide), this SoP does not apply.

For a claimant seeking to establish a connection between joint instability and relevant service, compliance with the SoP means identifying which of the 25 factors applies and gathering medical evidence that directly addresses the factor. The following steps are necessary.

First, obtain a clear diagnosis of joint instability as defined. The diagnosis must show that the condition is acquired (not congenital), due to damage or abnormality of stabilising structures, and manifests as recurrent subluxation, dislocation, or sprain. A diagnosis of “ankle instability” from a specialist who can document recurrent giving‑way is preferable. A simple MRI showing ligament damage is not enough unless it correlates with symptoms. If the joint has a prosthesis, the diagnosis must confirm that the instability is not due to loosening or migration of the fixation component. The claimant should ask the medical practitioner to explicitly address the exclusion in subsection 7(2)(c).

Second, identify the relevant factor(s). For example, if the onset followed a specific incident of trauma (e.g., a parachute landing causing a knee dislocation), factor (1) or (2) may apply. The factor must be “at the time of the clinical onset” meaning the trauma, dislocation, or sprain must be present at the time the instability first manifested. The medical report should include a timeline. If the condition worsened after service, factors (14) to (24) or (25) apply, but only if the condition pre‑existed and did not arise out of service.

Third, ensure that the factor is related to relevant service. Section 10(1) requires that the factor itself was related to service. For a trauma factor, the trauma must have occurred during the performance of relevant service. For pregnancy, the pregnancy must have been during service (not necessarily service‑caused, but the timing must coincide with service). For obesity, the obesity must have existed during service (or at the time of onset/worsening, which may be after service, but the factor must still be related to service - likely the obesity itself need not be service‑related, but the joint instability must be; this is ambiguous and may require legal argument).

Fourth, if the factor refers to an injury or disease covered by another SoP (e.g., fracture, rheumatoid arthritis), the claimant must also comply with that SoP. The decision‑maker will need to assess both SoPs. The claimant should prepare evidence for the secondary SoP as well. For instance, if factor (5) (fracture or bony abnormality) is relied upon, the fracture must be proven, and if there is a SoP for fracture (unlikely, but possibly under long‑term effects), the factors of that SoP must be met.

Fifth, for factors involving obesity, the claimant must provide accurate height and weight measurements at the relevant time. BMI should be calculated as per the formula in the dictionary (W/H²). If the claimant lost weight after service, evidence of weight at the time of clinical onset is critical. A medical record from that time is ideal. For morbid obesity (factor 9(12)), the claimant must argue that the clinical definition of morbid obesity applies because the SoP does not define it. The safest approach is to obtain an endocrinologist report stating the patient’s BMI and confirming morbid obesity as per standard criteria (usually BMI ≥ 40 or with comorbidities). Without a definition, there is risk of dispute.

Sixth, for the pregnancy factor, medical records confirming the pregnancy and the date of delivery (or termination) are needed, plus evidence that the joint instability onset or worsened within six weeks after that date.

Seventh, for the elbow injection factor, the claimant must have a history of more than three glucocorticoid injections for epicondylitis in the affected elbow before onset. Medical records from the treating practitioner should list the dates and doses. The injections must be for epicondylitis, not for other conditions.

Eighth, for the temporomandibular joint factor, the claimant must show that an activity or medical procedure involving wide mouth opening occurred at the time of onset or worsening. The examples include yawning, laughing, vomiting, coughing, chewing large food, dental procedures, laryngoscopy, and drug‑induced yawning. This factor is narrow and may require contemporaneous medical notes (e.g., dental records showing a difficult extraction).

Ninth, for the lumbar spine factor (total hip prosthesis instability only), the claimant must have one of the listed lumbar conditions (spondylosis, disc prolapse, spondylolisthesis, spinal stenosis, or fusion) at the time of onset or worsening. This requires imaging evidence (X‑ray, MRI) from that time.

Tenth, all medical reports should explicitly state that the factor existed “at the time of the clinical onset” or “at the time of the clinical worsening,” as applicable. The SoP does not require the factor to be the sole cause, but it must be present. The legal standard of reasonable hypothesis does not require proof beyond a reasonable doubt, only that there is a hypothesis that is reasonable. The SoP sets the minimum; if medical evidence is equivocal, the claim may still succeed if the factor is plausible.

Finally, the claimant should ensure that the factor is placed in the context of service. A statement from the veteran describing the relevant trauma during service, or a service medical record charting the pregnancy or obesity, will strengthen the link. The SoP is a gate, not a guarantee; the factor must be related to service, which is a legal question that may involve the character of the service (e.g., overseas deployment vs. training in Australia). Legal advice is recommended.