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 Hip replacement, hemiarthroplasty and post-replacement hip function
Hip replacement is assessed by a points system, not by the idea that surgery equals a fixed WPI. The assessor should score the stable result, including pain, function, walking tolerance, ROM, limp, aids and relevant deductions or apportionment issues.
What injuries can happen to this body part?
- Total hip replacement after femoral neck fracture, acetabular injury or post-traumatic arthritis
- Hip hemiarthroplasty where the NSW replacement scoring approach applies to the stable hip result
- Persistent pain, limp, restricted ROM, altered walking distance or need for a permanent aid after replacement
Symptoms and findings that matter
- Replacement type and operation record
- Pain and functional score at maximum medical improvement
- Walking distance, limp, cane or other aid use, and ability with stairs
- Hip ROM and clinical stability where the table requires it
- Whether pre-existing arthritis or non-work degeneration requires apportionment
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
- Hip replacement is assessed by a points system, not by the idea that surgery equals a fixed WPI. The assessor should score the stable result, including pain, function, walking tolerance, ROM, limp, aids and relevant deductions or apportionment issues.
- Assessment source: NSW Guidelines Chapter 3 paragraphs 3.29-3.30 and AMA5 hip replacement scoring where adopted by NSW. The local source verifies NSW walking-distance clarification and hemiarthroplasty treatment, but not every full conversion threshold.
- 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
- ROM is part of the clinical picture, but the replacement page should explain the points score rather than turning one movement into a fixed WPI.
- A good surgical result can still have some impairment, while a poor result needs objective findings rather than dissatisfaction alone.
Hip replacement point-system cautions
Points system, not fixed surgery valueHip replacement is scored under the adopted hip replacement table. The operation name alone does not set WPI.
Walking distance guidanceThe NSW Guidelines clarify that six blocks means about 600 m and three blocks means about 300 m.
HemiarthroplastyNSW rates hemiarthroplasty the same as total joint replacement where the method applies.
Clinical result mattersPain, walking tolerance, ROM, limp, aids and overall result must be assessed at MMI before conversion.
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.
Lower limb ROM and consistency rules
Use ROM only where validROM should be used only where the measurements are consistent and clinically reliable.
Same joint planesMultiple valid planes within the same lower limb joint are added, not combined, under the NSW lower limb method.
Opposite side comparisonIf the opposite side has reduced average mobility, the assessor should explain whether baseline deduction or comparison is needed.
Knee varus/valgus with arthritisVarus or valgus deformity due to compartment arthritis is not combined with ROM; both are calculated and the greater valid value is used.
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.
Practical WPI examples
- A worker who can walk longer distances with minimal pain may score differently from a worker with persistent limp and aid dependence.
- A hip replacement after a work-related femoral neck fracture may raise different causation questions from a replacement for long-standing osteoarthritis.
- NSW clarifies that six blocks is about 600 m and three blocks is about 300 m for hip replacement scoring language.
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
- Operation report
- Post-operative X-rays
- Orthopaedic review
- ROM and gait findings
- Physiotherapy notes
- Walking-aid prescription
- Work-capacity 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
- Writing surgery equals fixed WPI
- Using gait derangement as an add-on
- Ignoring apportionment where the replacement follows mixed traumatic and degenerative causes
Assessment source
Assessment source: Assessment source: NSW Guidelines Chapter 3 paragraphs 3.29-3.30 and AMA5 hip replacement scoring where adopted by NSW. The local source verifies NSW walking-distance clarification and hemiarthroplasty treatment, but not every full conversion threshold.
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 Hip Replacement WPI Assessment
The assessment scope for Hip Replacement 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 Hip Replacement
- 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.