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 Carpal tunnel syndrome and median nerve impairment
Carpal tunnel WPI should identify residual median nerve impairment at MMI. The assessment is not just a diagnosis label or a nerve conduction result. NSW also confirms that post-operative carpal tunnel is assessed the same way as non-operated carpal tunnel.
What injuries can happen to this body part?
- Median nerve compression at the wrist with numbness, tingling or night symptoms
- Carpal tunnel release with residual sensory or motor deficit
- Thenar weakness or wasting in more severe cases
- Symptoms overlapping with cervical radiculopathy, pronator syndrome, ulnar neuropathy or diabetic neuropathy
Symptoms and findings that matter
- Median nerve distribution and whether symptoms fit CTS rather than another nerve or neck condition
- Nerve conduction study findings where obtained
- Residual sensory loss, abnormal sensation, pain, thenar weakness or motor deficit at MMI
- Whether surgery occurred and whether residual impairment remains after release
- Work exposure, repetitive use, vibration, non-work risk factors and apportionment issues
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
- Carpal tunnel WPI should identify residual median nerve impairment at MMI. The assessment is not just a diagnosis label or a nerve conduction result. NSW also confirms that post-operative carpal tunnel is assessed the same way as non-operated carpal tunnel.
- Assessment source: NSW Guidelines Chapter 2 paragraphs 2.9 to 2.10, AMA5 Chapter 16 nerve methods where adopted by NSW, and AMA5 Section 16.5d for CTS concepts.
- 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
- CTS is a nerve assessment, not mainly a wrist ROM assessment.
- Typing, gripping, tool use and vibration exposure matter for work capacity and causation evidence, but grip loss and ROM are usually not separately rated for CTS itself.
NSW upper extremity assessment rules
Main methodAMA5 Chapter 16 applies to upper extremity WPI, subject to the NSW modifications in Chapter 2 of the SIRA Guidelines.
Stable diagnosisThe impairment must be permanent and stable, with a defined diagnosis confirmed by examination.
ROM reliabilityActive ROM is used for impairment calculation. Passive ROM can help clinical examination, but inconsistent ROM should not be used as a valid parameter.
ConversionUpper extremity impairment is converted to WPI using AMA5 Table 16-3 as adopted by NSW.
No double countingThe same loss should not be counted twice through ROM, nerve, strength, diagnosis-based or surgery methods.
Upper limb nerve and carpal tunnel rules
Sole peripheral nerve injuryIf the upper extremity impairment results solely from a peripheral nerve injury, do not also rate abnormal motion for that same upper extremity.
Peripheral nerve tablesUse AMA5 Table 16-15 together with Tables 16-10 and 16-11 for peripheral nerve lesions, as adopted by NSW.
Clinical judgementThe examiner must choose an appropriate percentage within the severity range. The maximum value is not applied automatically.
Carpal tunnel after surgeryPost-operative carpal tunnel syndrome is assessed in the same way as carpal tunnel without operation.
Grip strength and ROM in CTSWhere carpal tunnel is assessed as a nerve condition, grip loss and loss of ROM are usually not separately rated for CTS itself.
Practical WPI examples
- Post-operative CTS is assessed in the same way as CTS without operation.
- A positive nerve conduction study may support diagnosis, but WPI still depends on residual impairment at MMI.
- If the only ratable problem is median nerve impairment, abnormal motion should not also be rated for the same upper extremity.
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
- Nerve conduction studies, hand surgeon reports, GP notes, operative report, post-operative review, ergonomic/work-task evidence and symptom chronology
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
- Treating all hand numbness as CTS
- Adding grip loss or wrist ROM on top of CTS nerve impairment without a separate valid injury
- Ignoring cervical or ulnar nerve differential diagnoses
Assessment source
Assessment source: Assessment source: NSW Guidelines Chapter 2 paragraphs 2.9 to 2.10, AMA5 Chapter 16 nerve methods where adopted by NSW, and AMA5 Section 16.5d for CTS concepts.
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 upper extremity chapter: Source for NSW upper extremity assessment rules and AMA5 Chapter 16 adoption/modification points.
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 Carpal Tunnel and Nerve Injury WPI Assessment
The assessment scope for Carpal Tunnel and 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 Carpal Tunnel and 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.