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 Tibial plateau fracture and knee joint surface injury
Tibial plateau fracture WPI has a specific NSW table. The grade depends on the weight-bearing area, displacement and comminution, so the assessment should not treat all tibial plateau fractures as the same.
What injuries can happen to this body part?
- Undisplaced tibial plateau fracture
- Depressed, split, comminuted or displaced plateau fracture
- Meniscus, ligament or cartilage injury associated with the fracture
- Post-traumatic arthritis or later knee replacement after joint-surface injury
Symptoms and findings that matter
- Whether the fracture is undisplaced, mild, moderate or severe under NSW Table 3.2
- Weight-bearing area involvement
- Displacement, depression and comminution
- Residual ROM, instability, alignment and post-traumatic cartilage loss
- Whether later arthritis or replacement scoring supersedes or interacts with the fracture method
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
- Tibial plateau fracture WPI has a specific NSW table. The grade depends on the weight-bearing area, displacement and comminution, so the assessment should not treat all tibial plateau fractures as the same.
- Assessment source: NSW Guidelines Chapter 3 Table 3.2, which replaces the AMA5 tibial plateau fracture instruction.
- 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
- A tibial plateau fracture can reduce knee flexion or extension, but NSW Table 3.2 should be checked first for the fracture itself.
- Long-term restrictions often involve stairs, squatting, kneeling and standing tolerance.
NSW Table 3.2 tibial plateau fracture rows
Undisplaced tibial plateau fracture2% WPI (5% lower extremity impairment).
Mild tibial plateau fracture5% WPI (12% lower extremity impairment).
Moderate tibial plateau fracture10% WPI (25% lower extremity impairment).
Severe tibial plateau fracture15% WPI (37% lower extremity impairment).
Severity factorsThe grade depends on weight-bearing area involvement, displacement and comminution.
NSW arthritis and cartilage-loss rules
Cartilage loss definitionOsteoarthritis for lower limb WPI is assessed as cartilage loss, usually through radiologically determined joint-space intervals in AMA5 Table 17-31 as adopted by NSW.
Knee compartmentsThe knee has three compartments. The major impairment compartment is used; compartments are not added or combined.
Cannot combine with some methodsArthritis rating cannot be combined with gait disturbance, muscle atrophy, muscle strength or ROM.
Patello-femoral cautionPatello-femoral arthritis/crepitus is not added again when assessing arthritis of the knee joint itself.
Resurfacing proceduresNSW gives no additional impairment for resurfacing procedures for localised cartilage lesions or defects in major joints.
NSW corrected knee replacement scoring elements
Pain, ROM and stabilityThe corrected NSW Table 17-35 scores pain, ROM, anteroposterior stability and mediolateral stability before deductions.
ROM scoreAdd 1 point for each 5 degrees of knee motion, to a maximum of 25 points, under the corrected NSW table.
Flexion contracture deductionDeduct 2, 5, 10 or 20 points for flexion contracture from 5-9, 10-15, 16-20 or more than 20 degrees.
Extension lag deductionDeduct 5, 10 or 15 points for extension lag below 10, 10-20, or more than 20 degrees.
Alignment deductionAlignment deductions apply for varus or out-of-range valgus; constitutional variation should be checked against the unaffected limb.
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
- An undisplaced plateau fracture is a verified 2% WPI row where the NSW criteria fit.
- A severe comminuted fracture affecting the weight-bearing surface can fit the verified 15% WPI row where evidence supports that grade.
- Later arthritis should be assessed carefully so the same joint-surface damage is not counted twice.
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
- Initial X-rays
- CT scan
- Operation report
- Fracture clinic notes
- Weight-bearing knee X-rays
- Orthopaedic final report
- ROM and stability findings
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 a generic fracture percentage
- Ignoring weight-bearing area and displacement
- Adding fracture, arthritis and gait figures without checking NSW combination rules
Assessment source
Assessment source: Assessment source: NSW Guidelines Chapter 3 Table 3.2, which replaces the AMA5 tibial plateau fracture instruction.
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 Tibial Plateau Fracture WPI Assessment
The assessment scope for Tibial Plateau Fracture 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 Tibial Plateau Fracture
- 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.