What should be checked before relying on a WPI figure?
Check maximum medical improvement, the body area, objective findings, the NSW Guideline chapter and any NSW modification before relying on a percentage.
Can this page calculate your percentage?
No. WPI depends on an assessor, maximum medical improvement, objective findings and the NSW Guidelines. This page is general information only.
Permanent impairment assessment
How permanent impairment is assessed for Ankle ROM, instability, fracture, ankylosis and replacement
Ankle WPI should identify whether the residual problem is ROM loss, instability, fracture, arthritis, fusion/ankylosis, replacement or hindfoot alignment. The NSW corrected ankle ROM table and ankle replacement table are often more specific than a broad gait description.
What injuries can happen to this body part?
- Ankle sprain, syndesmosis injury or residual instability
- Ankle fracture involving the joint surface
- Post-traumatic ankle arthritis or cartilage loss
- Ankle fusion, ankylosis or replacement
Symptoms and findings that matter
- Plantar flexion, dorsiflexion/extension and flexion contracture using the corrected NSW table
- Instability, fracture union, alignment and arthritis/cartilage loss
- Fusion position or ankle replacement point score if applicable
- Tibia-os calcis angle where hindfoot alignment is the issue
- Whether gait is a last resort rather than an add-on
What investigations are usually relevant?
- Treating specialist report and final impairment assessment at maximum medical improvement
- Imaging, pathology, audiology, ophthalmology, respiratory, nerve or functional testing that fits the body system
- Operative reports, discharge summaries, rehabilitation records and objective clinical measurements where relevant
How WPI is assessed for this body part
- Ankle WPI should identify whether the residual problem is ROM loss, instability, fracture, arthritis, fusion/ankylosis, replacement or hindfoot alignment. The NSW corrected ankle ROM table and ankle replacement table are often more specific than a broad gait description.
- Assessment source: NSW Guidelines Chapter 3 corrected Table 17-11 ankle motion, Table 3.1 ankylosis, Table 3.3 ankle replacement and Table 3.4 tibia-os calcis angle.
- The assessor should explain maximum medical improvement, the body-system chapter, the method selected, any NSW modification, and why the objective findings fit that method.
How movement affects the assessment
- Reduced dorsiflexion can affect stairs, squatting and walking up inclines.
- Reduced plantar flexion can affect push-off and uneven surfaces.
- Inconsistent ROM measurements should be treated cautiously and explained.
NSW corrected Table 17-11 ankle motion rows
Mild ankle motion impairment3% WPI (7% lower extremity impairment; 10% foot impairment): plantar flexion 11-20 degrees, flexion contracture 1-10 degrees, or extension 10-0 degrees to neutral.
Moderate ankle motion impairment6% WPI (15% lower extremity impairment; 21% foot impairment): plantar flexion 1-10 degrees or flexion contracture 11-19 degrees.
Severe ankle motion impairment12% WPI (30% lower extremity impairment; 43% foot impairment): no plantar flexion capability or flexion contracture of 20 degrees or more.
NSW Table 3.3 total ankle replacement point categories
Good result, 85 to 100 points12% WPI (30% lower extremity impairment).
Fair result, 50 to 84 points16% WPI (40% lower extremity impairment).
Poor result, less than 50 points20% WPI (50% lower extremity impairment).
NSW Table 3.1 optimal ankylosis values
Hip ankylosis, optimal position20% WPI (50% lower extremity impairment).
Knee ankylosis, optimal position27% WPI (67% lower extremity impairment).
Ankle ankylosis, optimal position15% WPI (37% lower extremity impairment; 53% foot impairment).
Pantalar ankylosis, optimal position19% WPI (47% lower extremity impairment; 67% foot impairment).
Triple ankylosis, optimal position6% WPI (15% lower extremity impairment; 21% foot impairment).
Subtalar ankylosis, optimal position4% WPI (10% lower extremity impairment; 14% foot impairment).
Not in optimum positionThe NSW Guidelines add, rather than combine, the variation-from-optimum values in Table 3.1(a).
NSW foot and ankle specific rows
Tibia-os calcis angle 110 to 100 degrees5% WPI (12% lower extremity impairment; 17% foot impairment) under NSW Table 3.4.
Tibia-os calcis angle 99 to 90 degrees8% WPI (20% lower extremity impairment; 28% foot impairment) under NSW Table 3.4.
Tibia-os calcis angle below 90 degreesAdd 1% WPI (2% lower extremity impairment; 3% foot impairment) per degree, up to 15% WPI (37% lower extremity impairment; 54% foot impairment).
Persistent plantar fasciitisPersistent symptoms and clinical findings after 18 months are rated at 1% WPI (2% lower extremity impairment).
NSW lower limb global rules
Most specific method firstUse the method that most specifically addresses the lower limb impairment where possible, rather than a broad fallback label.
Highest valid assessmentWhere more than one valid lower limb method applies, the NSW Guidelines generally require the assessment that gives the highest valid rating, unless a specific rule prevents it.
Do not exceed amputation valueA lower limb part or region cannot exceed the applicable amputation value. The whole lower limb maximum is 40% WPI, except where a specific gait table gives WPI directly.
Gait derangement is last resortGait derangement should be used only as a last resort and cannot be combined with other lower extremity assessment methods.
Permanent walking aid onlyIf a walking aid is relied on, the evidence should show permanent use, not a temporary aid during treatment or recovery.
ROM reliabilityROM can be unreliable where effort, pain behaviour or inconsistency affects measurement. The opposite side should be compared where relevant.
Arthritis needs imagingArthritis/cartilage loss must be radiologically assessed. Pain, crepitus or a broad MRI comment is not enough by itself.
Practical WPI examples
- Moderate corrected ankle ROM impairment is verified at 6% WPI where the NSW criteria fit.
- A fair ankle replacement result is verified at 16% WPI under NSW Table 3.3 where the point score is 50-84.
- A permanent limp after ankle injury should not bypass the specific ankle ROM, replacement, ankylosis or arthritis methods.
Evidence checklist
- A clear diagnosis and the body area being assessed
- Records showing the condition has reached maximum medical improvement, if that is the issue
- Specialist reports, imaging reports and treating notes relied on by the assessor
- Objective findings on examination, not only symptoms described by the injured person
- A work and treatment chronology explaining the injury, treatment, surgery and recovery path
- Any previous injury, degeneration, congenital issue or non-work cause that needs apportionment considered
- Weight-bearing ankle X-rays
- CT/MRI
- Orthopaedic report
- ROM measurements
- Stability findings
- Replacement/fusion operation notes
- Gait and work-duty records
What usually does not increase WPI
- Assuming a scan result automatically gives a WPI percentage
- Confusing pain, disability or inability to work with permanent impairment
- Ignoring maximum medical improvement before arranging an assessment
- Using an AMA5 table without checking whether the NSW Guidelines modify or replace it
- Double counting the same impairment through two methods when the Guidelines require one method
- Applying gait derangement too early
- Using uncorrected AMA ankle ROM rows instead of the NSW correction
- Ignoring the maximum ankle ankylosis and variation rules
Assessment source
Assessment source: Assessment source: NSW Guidelines Chapter 3 corrected Table 17-11 ankle motion, Table 3.1 ankylosis, Table 3.3 ankle replacement and Table 3.4 tibia-os calcis angle.
This section is source-backed general information. It is not a WPI assessment and is not legal advice.
- SIRA NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment: Source for the NSW assessment framework, MMI, AMA5 adoption, NSW modifications and exclusions.
- SIRA lower extremity chapter: Source for NSW lower extremity assessment rules, gait derangement limits and NSW-modified lower limb tables.
Related injury and claim pages
Need a practical claim check?
If an impairment percentage, medical assessment or insurer decision is affecting your NSW injury claim, send the decision or report for a practical review. This is general information only and does not guarantee any result.
Request a free claim checkAssessment scope for Ankle WPI Assessment
The assessment scope for Ankle WPI Assessment should be stated precisely before any percentage is considered. The file should identify whether that label describes the primary diagnosed condition, a symptom of another injury, a regional overview or one component of a broader impairment. Findings from another body area or diagnosis should not be transferred without explanation. The report should connect the stated condition to the correct NSW Guideline chapter, objective findings, treatment history and any permitted combination or apportionment method. This distinction is particularly important where similar page labels cover different clinical questions.
- Confirm the diagnosis and body area being assessed as Ankle
- Separate condition-specific findings from overlapping symptoms or injuries in another body area
- Check that the selected NSW Guideline chapter and method match the condition actually assessed
- Explain any combination, apportionment or exclusion rather than relying on the page label alone
Start with maximum medical improvement
Permanent impairment should generally be assessed when the condition is stable and unlikely to change substantially in the next year. Treatment, surgery and rehabilitation history may affect whether the timing is appropriate.
Use the NSW Guidelines first
The NSW Guidelines adopt AMA5 in many areas, but NSW modifications prevail. Do not assume an AMA5 table applies without checking the NSW chapter and any public SIRA clarification.
Keep the assessment practical
A useful assessment file separates diagnosis, objective findings, surgery history, work capacity issues, apportionment questions and the body-area method used by the assessor.
Ask about an impairment issueDocuments and records
Injury evidence to organise early
The useful records depend on how the injury happened, when symptoms were recorded and how treatment or work capacity changed.
- Date, location and short description of the injury event
- Medical certificates, reports, scans, treatment records or hospital documents
- Employer, insurer, police, incident or venue records where relevant
- Photos, witness details, dashcam or other supporting material if available
- Income, superannuation, work capacity or leave records where relevant
- Letters, emails, claim numbers and decisions already received
Common questions
Injury evidence questions
Short general answers only. The right next step depends on the facts, dates and documents.
Is WPI the same as being unable to work?
No. WPI is a medical impairment measure. Work capacity, weekly payments, damages, treatment disputes and TPD issues are separate questions, although the evidence may overlap.
Does pain alone create a WPI percentage?
Not by itself. NSW workers compensation excludes AMA5 Chapter 18 on pain. Chronic pain is assessed through the underlying diagnosed condition where the Guidelines permit it.
Can secondary psychological symptoms be added to physical WPI?
In NSW workers compensation, secondary psychiatric or psychological impairment is not assessed as permanent impairment. Primary psychological impairment is assessed separately and is not combined with physical WPI.
Injury pathway enquiry
Not sure which claim type matches the injury?
Start with how the injury happened, what medical records exist and how work or daily activity has changed. The same injury can sit in different pathways.