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Plain English answer
How this assessment usually works
Lower limb impairment assessment usually looks beyond the diagnosis label. The practical question is how the accepted injury affects walking, standing, stairs, kneeling, squatting, driving, gait, surgery outcome and durable work capacity.
The assessor does not decide legal liability. The assessment is a medical opinion about permanent impairment under the NSW workers compensation guidelines. The legal importance is what the percentage does to Section 66, weekly payments, medical expense time limits, settlement strategy or work injury damages preparation.
Step 1
Accepted injury
Check the accepted injury wording, body system and mechanism before looking at the percentage.
Step 2
Medical method
Check whether the correct NSW guideline method, clinical findings and records were used.
Step 3
Claim effect
Check what the WPI percentage changes before accepting a report or settlement position.
What the assessor usually checks
- accepted hip, knee, ankle, foot, ligament, meniscus, fracture or replacement injury wording
- whether imaging and surgery records match ongoing symptoms
- movement, stability, gait, use of aids and work function
- whether arthritis or degeneration is being treated as unrelated despite work aggravation evidence
- whether multiple lower-limb problems are assessed together or separated correctly
Evidence that may help
A useful WPI report depends on the material the assessor receives. These records often matter for hip, knee, leg, ankle and foot:
- MRI, X-ray, arthroscopy, replacement or fracture records
- orthopaedic, rehabilitation physician, physiotherapist and GP reports
- capacity certificates covering walking, standing, kneeling, stairs, driving and lifting
- worksite material showing standing tasks, uneven ground, ladders, deliveries or manual handling
- records of failed suitable duties or recurrent flare-ups after return to work
Common insurer or report disputes
- the insurer says arthritis is the real cause
- the assessment ignores gait, instability or repeated swelling
- surgery outcome is described as successful even though function remains restricted
- work capacity is assumed because the worker can walk short distances
- a combined injury is split in a way that understates overall functional effect
Questions to ask when the report comes back
How this connects to thresholds and strategy
SIRA says permanent impairment compensation generally requires 11% or more permanent impairment for physical injury, and 15% or more for primary psychological injury. Secondary psychological injury is treated differently. Those thresholds are not a payout promise; they are eligibility and strategy checkpoints that need to be applied to the accepted injury and current evidence.
A low WPI opinion may also affect weekly-payment planning, treatment time-limit issues, dispute posture, and whether work injury damages threshold advice is required. The safest approach is to review the method, evidence and consequences before signing or letting the insurer rely on a weak assessment.
Questions workers often ask
Is hip, knee, leg, ankle and foot assessed the same way as every other injury?
No. NSW permanent impairment assessment depends on the accepted injury, body system, medical evidence, maximum medical improvement and any NSW-specific guideline modification. The assessment method for hip, knee, leg, ankle and foot should be checked against the injury actually accepted in the claim.
Can I calculate the WPI percentage myself?
No. A trained permanent impairment assessor must perform the assessment. A worker can still check whether the report used the correct injury description, records, body system, causation assumptions and deduction reasoning.
What if the insurer report seems too low?
Ask for the report and the material sent to the assessor. For hip, knee, leg, ankle and foot, compare the report against treating records, imaging, specialist material, work duties and certificates of capacity before accepting the percentage or relying on it for settlement strategy.
Does maximum medical improvement matter?
Yes. SIRA guidance says permanent impairment assessment should occur when the condition has stabilised and is unlikely to change substantially in the next year with or without treatment. If treatment is incomplete, the timing may need review.
General information only
This information is general in nature and is not legal advice. You should obtain advice about your own circumstances before relying on a WPI percentage, accepting a lump sum offer, or responding to an insurer decision.
Reviewed by NSW Work Injury Claims - a branch of Stephen Young Lawyers.
Related injury and impairment pages
Need a WPI assessment checked?
If the percentage does not match the accepted injury, treatment history, imaging, surgery, work duties or current restrictions, get the report checked before accepting the insurer position.