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 Lower limb peripheral nerve injury, sensory loss and motor loss
Lower limb nerve WPI should identify the named nerve and objective deficit. NSW says lower limb peripheral nerve injury should be assessed by nerve where possible, rather than using gait as a broad substitute.
What injuries can happen to this body part?
- Common peroneal nerve injury affecting foot drop or dorsum foot sensation
- Tibial or posterior tibial nerve symptoms affecting plantar foot sensation or motor function
- Sciatic or femoral nerve injury after trauma, surgery or fracture
- Entrapment or laceration with objective sensory or motor deficit
Symptoms and findings that matter
- Named nerve and whether deficit is sensory, motor, dysaesthetic or mixed
- Objective sensory testing, motor grade, reflexes and muscle wasting where relevant
- EMG/NCS where obtained and clinically useful
- Whether symptoms are actually spinal radiculopathy rather than peripheral nerve injury
- Whether combination with gait, atrophy, strength or CRPS is prohibited
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
- Lower limb nerve WPI should identify the named nerve and objective deficit. NSW says lower limb peripheral nerve injury should be assessed by nerve where possible, rather than using gait as a broad substitute.
- Assessment source: NSW Guidelines Chapter 3 paragraphs 3.32-3.35 and AMA5 lower extremity peripheral nerve method where adopted and modified by NSW.
- 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
- Nerve injury may affect ankle control, foot clearance, balance and safe walking, but the nerve method should be used where possible.
- ROM loss should not be used to count the same motor deficit twice.
NSW lower limb peripheral nerve rules
Assess by nerve where possibleLower limb peripheral nerve injury should be assessed by the nerve method rather than gait where possible.
Motor, sensory and dysaesthetic componentsSeparate motor, sensory and dysaesthetic components are combined under the NSW lower limb nerve method.
Posterior tibial nerveBecause posterior tibial nerve is not listed in AMA5 Table 17-37, NSW calculates it by subtracting common peroneal ratings from sciatic nerve ratings.
No combination with gait/atrophy/strength/CRPSLower limb peripheral nerve impairment is not combined with gait derangement, muscle atrophy, muscle strength or CRPS where the Guidelines prohibit overlap.
NSW gait derangement limits
Last resort onlyUse gait derangement only where no more specific lower limb method adequately assesses the impairment.
No combinationDo not combine gait derangement with another lower extremity method such as ROM, arthritis, muscle atrophy, nerve impairment or replacement scoring.
Pathological supportThe gait finding should be supported by objective pathology and examination findings, not only subjective walking difficulty.
Trendelenburg deletionNSW deletes the Trendelenburg item in AMA5 Table 17-5 because it is considered insufficiently reliable.
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
- Foot drop after a common peroneal nerve injury is different from pain-limited walking after ankle fracture.
- Posterior tibial nerve is handled by the NSW subtraction method because it is not separately listed in AMA5 Table 17-37.
- Leg numbness from lumbar radiculopathy should be separated from a peripheral nerve lesion.
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
- Neurologist report
- EMG/NCS if obtained
- Sensory map
- Motor testing
- Operative or trauma records
- Gait and brace records
- Spine imaging if radiculopathy is a competing explanation
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
- Using gait derangement instead of a nerve method
- Counting nerve deficit again as muscle strength or atrophy where prohibited
- Confusing radiculopathy with a peripheral nerve injury
Assessment source
Assessment source: Assessment source: NSW Guidelines Chapter 3 paragraphs 3.32-3.35 and AMA5 lower extremity peripheral nerve method where adopted and modified by NSW.
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.
- SIRA nervous system chapter: Source for nervous system assessment concepts including brain, spinal cord and peripheral nerve impairment.
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 Lower Limb Nerve Injury WPI Assessment
The assessment scope for Lower Limb Nerve Injury 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 Lower Limb Nerve Injury
- 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.