Hip, knee, leg, ankle and foot WPI Assessment NSW

Legal service provider

NSW workers compensation help from Stephen Young Lawyers

NSW Work Injury Claim is the workers compensation service of Stephen Young Lawyers. Stephen Young Lawyers provides the legal service. Stephen Young Lawyers.

Stephen Young Lawyers was established in 2012. The firm is led by Stephen Young, Principal Solicitor and Accredited Specialist in Personal Injury Law.

Workers across New South Wales can arrange telephone or video appointments. In-person appointments can be arranged at the Sydney office when appropriate.

NSW Work Injury Claim enquiries: (02) 7233 3661

Content publisher:: NSW Work Injury Claim
Published:: 23 June 2026
Last legally reviewed:: 25 July 2026

Key legal sources

This information is general in nature and is not legal advice. You should obtain advice about your own circumstances.

A physiotherapist observing a worker walking during a lower-limb assessment.

Assessment overview

How this assessment usually works

Lower-limb WPI is not a general score for pain or difficulty walking. The assessor identifies the accepted hip, knee, ankle, foot, muscle or nerve condition, chooses the most specific NSW method, records the required measurements and explains which competing methods cannot be combined. Joint replacement uses a points worksheet; arthritis requires radiological cartilage loss; gait is a last resort.

For hip, knee, leg, ankle and foot, the assessor gives a medical opinion about permanent impairment under the NSW workers compensation guidelines; the assessor does not decide legal liability. Once the body-system method and percentage are understood, separate advice may be needed about Section 66 compensation, weekly payments, medical-expense time limits or work injury damages.

Injuries and diagnoses assessed in this body system

The referral and report should identify the accepted diagnosis precisely. Similar symptoms can use different assessment methods depending on the injured structure.

hip labral, chondral and tendon injury; femoral neck, head and acetabular fracture; post-traumatic arthritis; and total hip replacement or hemiarthroplasty
meniscal tear or meniscectomy; ACL, PCL, MCL or LCL tear and residual laxity; patella or patello-femoral injury; tibial plateau fracture; cartilage loss; and total or isolated patello-femoral replacement
malleolar or syndesmosis injury, ligament instability, osteochondral injury, ankle or hindfoot ankylosis, total ankle replacement and post-traumatic arthritis
calcaneal, talar, midfoot, metatarsal and toe injury; Lisfranc injury; plantar fasciitis; tendon injury; and fixed foot deformity
true structural leg-length discrepancy, unilateral thigh or calf atrophy, rateable muscle weakness, named peripheral nerve injury, gait derangement and lower-limb CRPS

When a permanent impairment assessment can occur

For hip, knee, leg, ankle and foot, assessment should occur only after maximum medical improvement (MMI). Under NSW Guidelines paragraph 1.15, that means the condition is well stabilised and unlikely to change substantially during the next year, with or without treatment.

For hip, knee, leg, ankle and foot, if treatment or rehabilitation is inadequate and could materially change the impairment, paragraph 1.16 says the assessment should be deferred. The report should explain the timing rather than merely state that MMI has been reached.

For hip, knee, leg, ankle and foot, after fracture fixation, reconstruction or joint replacement, the report should address whether rehabilitation, motion, stability, alignment and any proposed revision have stabilised. Surgery is not a fixed percentage and does not itself prove MMI.

The NSW and AMA5 assessment method

The NSW Workers Compensation Guidelines prevail over AMA5 wherever the two differ. The method is a medical assessment framework, not a self-scoring exercise.

NSW Guidelines Chapter 3 applies AMA5 Chapter 17 subject to NSW corrections. The NSW Guidelines prevail where they differ from AMA5.

The assessor uses the most specific valid method. If more than one method validly describes the same impairment, the highest valid result is generally selected rather than added. A combination is permitted only where the NSW rules and AMA5 Table 17-2 allow it and the same loss is not counted twice.

Joint range of motion is measured three times in each relevant plane and the greatest valid result is used. Materially inconsistent readings are not a valid ROM parameter. Manual leg-length measurement is different: three readings are averaged.

Manual muscle weakness uses the six Medical Research Council grades from 0 to 5 and AMA5 Table 17-8. The grades are ordinal rather than evenly spaced, and electrodiagnostic results do not replace the manual strength examination.

Diagnosis-based estimates can apply to specified injuries such as meniscectomy or residual ligament laxity. Arthritis requires radiologically measured cartilage loss. A replacement is assessed through the prescribed points worksheet, not the operation name.

Gait derangement is a last-resort standalone method and cannot be combined with another lower-limb evaluation. Atrophy, manual muscle weakness, named-nerve loss and gait must not be stacked where they describe the same strength or walking loss.

NSW paragraph 1.24 says activities of daily living do not alter a calculated lower-extremity rating. Daily activities can explain practical impact, but they are not an additional percentage or deduction.

What the assessor actually measures

For hip, knee, leg, ankle and foot, the percentage should be traceable to relevant, stable and reproducible findings.

hip flexion, bringing the knee towards the chest; extension, moving the leg behind the body; abduction and adduction, moving away from and towards the midline; and internal and external rotation, turning the thigh inward and outward
knee flexion, bending; extension, straightening; flexion contracture, inability to straighten fully; extension lag, inability to reach the available full extension actively; anteroposterior and mediolateral instability; and varus or valgus alignment
ankle dorsiflexion, bringing the toes towards the shin; plantarflexion, pointing the foot down; inversion and eversion, turning the sole inward and outward; tibia-os calcis angle; hindfoot alignment; and any true ankylosis
radiological cartilage interval, using the worst valid knee compartment rather than adding medial, lateral and patello-femoral compartments
replacement pain and function, walking distance, aids, stairs, movement, stability and alignment using the relevant hip, knee or ankle points worksheet
true limb length; unilateral thigh circumference 10 cm above the patella; calf circumference at the same maximum level; MRC muscle grade; and anatomically matching sensory or motor loss in a named nerve

How the measurements are converted to WPI

Movement values in different planes of one joint are added. Regional values from the same limb must be expressed in the same unit before any permitted combination, then lower-extremity impairment is converted to WPI through AMA5 Table 17-3.

A diagnosis-based estimate, ROM, radiological arthritis, atrophy, strength, nerve, gait or replacement method is not automatically cumulative. The report should state why each selected method may be used and why any other apparent method is excluded or not combined.

The impairment of a body part cannot exceed its amputation value. NSW paragraph 3.7 caps a lower limb at 40% WPI except where a specific gait table supplies WPI directly.

Pre-existing impairment is addressed only after the current permanent impairment has been assessed, using the NSW deduction rules and supported evidence rather than an assumed deduction for age or degeneration.

Verified category and table examples

These short examples show how the published method works. They do not predict an individual assessment.

Finding or category	Published value or method	Source
True leg-length discrepancy	2-2.9 cm: 3% WPI (8% LEI); 3-3.9 cm: 5% WPI (13% LEI); 4-4.9 cm: 7% WPI (18% LEI); 5 cm or more: 8% WPI (19% LEI)	NSW-corrected AMA5 Table 17-4
Unilateral thigh or calf atrophy	1-1.9 cm: 2% WPI (6% LEI); 2-2.9 cm: 4% WPI (11% LEI); 3 cm or more: 5% WPI (12% LEI)	NSW-corrected AMA5 Table 17-6
Corrected ankle range-of-motion criteria	plantarflexion 11-20 degrees: mild 3% WPI (7% LEI/10% foot); 1-10 degrees: moderate 6% (15%/21%); none: severe 12% (30%/43%). Flexion contracture of 1-10, 11-19 and 20+ degrees uses the same mild, moderate and severe values; extension from 10 degrees to neutral is mild 3% WPI.	NSW-corrected AMA5 Table 17-11
Optimum-position ankylosis	hip: 20% WPI; knee: 27%; ankle: 15%; pantalar: 19%; triple: 6%; subtalar: 4%	NSW Guidelines Table 3.1
Tibial plateau fracture	undisplaced: 2% WPI; mild: 5%; moderate: 10%; severe: 15%	NSW Guidelines Table 3.2
Residual mild cruciate or collateral laxity	5% WPI (12% LEI)	NSW correction to AMA5 Table 17-33 diagnosis-based estimates
Tibia-os calcis angle	110-100 degrees: 5% WPI (12% LEI/17% foot); 99-90 degrees: 8% (20%/28%); below 90 degrees: add 1% WPI (2% LEI/3% foot) per degree, capped at 15% WPI (37% LEI/54% foot)	NSW Guidelines Table 3.4
Persistent plantar fasciitis	persistent symptoms and clinical findings after 18 months: 2% LEI (1% WPI)	NSW Guidelines paragraph 3.28
Isolated patello-femoral joint replacement	assess the knee in the usual way and combine with 9% WPI (22% LEI)	NSW Guidelines paragraph 3.28
Knee replacement pain score	none 50; mild or occasional 45; stairs only 40; walking and stairs 30; moderate occasional 20; continual 10; severe 0 points	NSW-corrected AMA5 Table 17-35
Knee replacement movement and stability score	1 point per 5 degrees of motion, maximum 25; AP stability 10/5/0; ML stability 15/10/5/0 according to the corrected bands	NSW-corrected AMA5 Table 17-35
Ankle replacement result	good 85-100 points: 12% WPI; fair 50-84: 16%; poor below 50: 20%	NSW Guidelines Table 3.3

Worked illustrations

How the assessment method can operate

These paraphrased illustrations explain the published method. They are not estimates of another worker's WPI.

Illustration: total knee replacement using the corrected NSW score

Assumed findings: A worker has a stable total knee replacement. The prescribed pain, motion, stability, flexion contracture and extension-lag items produce 33 points before alignment is applied. The measured alignment is 2 degrees valgus.

Method and arithmetic: The base AMA5 example applied no alignment deduction, but the NSW-corrected Table 17-35 deducts 3 points for each degree in the 0-4 degree valgus band. The 6-point deduction produces 27 points. Table 17-33 classifies that assumed result as poor and converts it to 30% WPI.

What the illustration shows: The operation does not create 30% WPI automatically. The result follows from every assumed score item and the NSW alignment correction. This paraphrased illustration is not an estimate for the reader.

Method source: NSW Guidelines paragraphs 3.29-3.30 and corrected AMA5 Table 17-35; AMA5 Table 17-33

Illustration: hip replacement points

Assumed findings: A stable hip replacement has prescribed pain, function, walking, aid, movement and deformity findings that total 78 points under Table 17-34.

Method and arithmetic: Table 17-33 classifies the assumed 78-point result as fair, corresponding to 50% lower-extremity impairment. Table 17-3 converts that regional value to 20% WPI.

What the illustration shows: Different clinical findings produce a different score. A hip replacement is not automatically 20% WPI. This paraphrased illustration is not an estimate.

Method source: NSW Guidelines paragraphs 3.29-3.30; AMA5 Tables 17-3, 17-33 and 17-34

Illustration: true leg-length discrepancy

Assumed findings: Three valid manual measurements after a healed fracture are 3.8 cm, 4.0 cm and 4.2 cm. Pelvic tilt and joint contracture have been excluded as causes of apparent shortening.

Method and arithmetic: Manual readings are averaged, not selected by taking the greatest result. The average is 4.0 cm. The corrected Table 17-4 row for 4-4.9 cm gives 18% LEI, equivalent to 7% WPI.

What the illustration shows: The table concerns true structural discrepancy. This illustration is not an estimate for the reader.

Method source: NSW Guidelines paragraphs 3.8-3.9; NSW-corrected AMA5 Table 17-4

Illustration: corrected ankle movement band

Assumed findings: Three clinically consistent plantarflexion readings produce a greatest valid result of 8 degrees, with no other permitted same-joint movement component assumed.

Method and arithmetic: Eight degrees falls within the corrected moderate plantarflexion band of 1-10 degrees. The corrected Table 17-11 row gives 15% LEI, equivalent to 6% WPI.

What the illustration shows: The result depends on valid repeated readings and any permitted same-joint calculation. It is not an estimate for the reader.

Method source: NSW Guidelines paragraphs 3.16-3.17; NSW-corrected AMA5 Table 17-11

Illustration: unilateral calf atrophy

Assumed findings: The unaffected comparison leg is normal. Repeated same-level maximum calf measurements show a stable 2.4 cm difference attributable to the accepted injury.

Method and arithmetic: The corrected Table 17-6 row for a 2-2.9 cm calf difference gives 11% LEI, equivalent to 4% WPI.

What the illustration shows: Atrophy is not then added to gait, manual strength or nerve loss if that would rate the same weakness twice. This illustration is not an estimate.

Method source: NSW Guidelines paragraphs 3.13-3.15; NSW-corrected AMA5 Table 17-6

Illustration: tibial plateau fracture grade

Assumed findings: A healed fracture involves a meaningful part of the weight-bearing plateau, with displacement and comminution supporting the moderate grade.

Method and arithmetic: NSW Table 3.2 gives the moderate grade 25% LEI or 10% WPI. Pain severity and the fact of fixation do not choose the grade.

What the illustration shows: The classification must follow the imaging and healed structural findings. This illustration is not an estimate.

Method source: NSW Guidelines Table 3.2

Illustration: ankle replacement points

Assumed findings: A stable ankle replacement produces 72 points after the prescribed pain, movement, limp, aid, distance, stairs and alignment items are completed.

Method and arithmetic: NSW Table 3.3 places 72 points in the fair 50-84 band, which gives 40% LEI or 16% WPI.

What the illustration shows: A different completed score may be good or poor. The prosthesis itself does not select the band. This illustration is not an estimate.

Method source: NSW Guidelines paragraph 3.28 and Table 3.3

What does not establish WPI by itself

These matters can remain medically and practically important, but they do not replace the measurements or category requirements in the applicable method.

pain, tenderness, swelling, clicking, giving way or difficulty walking without a valid diagnosis-based or measurable impairment method
arthritis assumed from symptoms, osteophytes or a diagnosis label without the required radiological cartilage measurement
inconsistent movement measurements, apparent rather than true shortening, or circumference comparison against an abnormal opposite limb
a limp where a more specific pathology-based method is valid, or temporary use of an aid treated as a permanent gait requirement
joint replacement, reconstruction or other surgery described as surgery equals a fixed percentage
weekly-payment restrictions, job loss or activities of daily living used to alter the calculated WPI result

Evidence checklist

The assessor should receive enough material to test the accepted injury, stability, measurable impairment and any deduction.

the accepted injury description, claim history and any insurer liability decisions
contemporaneous GP and treating-specialist records
relevant imaging, pathology, operation reports and rehabilitation records
earlier impairment assessments and records about any pre-existing impairment
a current treatment history and an explanation of whether further material improvement is expected
weight-bearing radiographs and relevant CT, MRI, ultrasound, arthroscopy or operation records identifying the side, compartment, fracture grade, prosthesis or named nerve
three reproducible joint-motion readings in each relevant plane, with the greatest valid result recorded and any inconsistency explained
replacement worksheets showing every pain, function, walking, aid, motion, stability, alignment, contracture and lag item that applies
same-level bilateral limb-length or circumference measurements, with three manual length readings averaged and the comparison limb confirmed as suitable
stability, alignment, MRC muscle grade, sensory mapping, motor testing and EMG/NCS where those methods are clinically relevant
a calculation sheet identifying the selected method, excluded methods, permitted combinations, regional unit, Table 17-3 conversion and rounding

Common insurer or report disputes

A disagreement about hip, knee, leg, ankle and foot WPI may concern the accepted diagnosis, the body-system findings, the selected method, a deduction or the way another impairment was handled. The report should identify the disputed step rather than leave the percentage unexplained.

arthritis is assumed from symptoms or a diagnosis label rather than the required cartilage measurement
inconsistent ROM is used, or the assessor takes the wrong reading instead of the greatest valid repeated result
surgery is treated as a fixed percentage without the replacement or diagnosis-based method being completed
a diagnosis-based estimate, ROM, atrophy, strength, nerve or gait value is added when the same loss cannot be rated twice
a pre-existing impairment deduction is assumed from age or degeneration without the evidence and reasoning required by the NSW Guidelines

Report cautions before relying on the percentage

Report red flags

A lower-limb WPI is stated without showing the regional impairment and conversion calculation.
A worker with a knee replacement, ACL reconstruction or fracture fixation is assessed without operation notes or updated orthopaedic review.
Gait is used as a rating method simply because the worker limps, without explaining pathology and combination limits.
The report treats capacity to walk briefly in the examination room as proof of durable work capacity.

Method and reliance checks

Does the report identify whether the rating is WPI, lower extremity impairment or foot impairment before conversion?
Does it avoid combining methods that the NSW guideline or AMA5 cross-usage rules do not permit?
If arthritis or degeneration is mentioned, does the report explain work aggravation and any deduction?
Does the examination match standing, walking, stairs, kneeling and safe-duty evidence?
Does the report explain the surgery outcome and whether MMI has been reached after rehabilitation?
If gait derangement is used, does the report explain why it is clinically appropriate and not double-counting another method?
Being able to walk a short distance does not necessarily answer durable work capacity, but WPI and work capacity remain different questions.
A successful operation can still leave permanent impairment, but the report must explain the remaining impairment method.
The maximum lower-limb rating is limited by the relevant amputation value.

Guideline notes

NSW lower extremity assessment modifies AMA5 Chapter 17.
Where several methods are available, the assessor should use the most clinically accurate permitted method and explain combination rules.

Sources for this assessment guide

The public NSW Guidelines control where they modify AMA5. AMA5 table references below identify the method without reproducing the proprietary table in full.

NSW Guidelines paragraphs 1.15-1.16, 1.24 and 1.26; Chapter 3, paragraphs 3.2-3.35 and Tables 3.1-3.4: MMI, ADL exclusion, method selection, maximum, gait, length, movement, atrophy, arthritis, replacement, diagnosis-based, nerve and CRPS corrections.
AMA5 Chapter 17, Tables 17-2 to 17-6, 17-10 to 17-11, 17-31 and 17-33 to 17-37: regional conversion, permitted methods, movement, cartilage interval, diagnosis-based, replacement and named-nerve calculations only as adopted and corrected by NSW.

Questions to ask when the report comes back

These questions help identify whether the report explains its method and evidence. They do not replace medical or legal advice about the particular assessment.

Which specific NSW/AMA5 method did the assessor use, and why was it the most specific valid method?
Were three valid movement readings recorded in every relevant plane?
If there is arthritis, what radiological cartilage interval was measured?
If there is a replacement, is the complete points worksheet attached or reproducible from the report?
Were gait, atrophy, muscle weakness and nerve loss kept from duplicating the same functional loss?
Did the report keep activities of daily living out of the percentage calculation as NSW paragraph 1.24 requires?

How this connects to thresholds and strategy

In a hip, knee, leg, ankle and foot claim, SIRA's permanent impairment thresholds must be applied to the accepted injury and the supported body-system percentage. The general thresholds are 11% or more permanent impairment for physical injury and 15% or more for primary psychological injury; secondary psychological injury is treated differently. A threshold is an eligibility checkpoint, not a promised payment.

A low hip, knee, leg, ankle and foot WPI opinion may affect weekly-payment planning, treatment time-limit issues, dispute posture and whether work injury damages threshold advice is required. Before the opinion is relied on, check the relevant measurements, body-system method, deduction and practical consequences.

Questions workers often ask

Does a knee or hip replacement have one fixed WPI?

No. Joint replacements use the applicable scoring method, including the required pain, function, movement, stability or alignment findings.

Which of three movement readings is used?

For lower-limb joint movement, the assessor normally records three readings in each plane and uses the greatest valid result. Material inconsistency makes ROM invalid. Manual leg-length measurement is different: three readings are averaged.

Can gait derangement be added to another lower-limb method?

No. NSW treats gait derangement as a last-resort standalone method. It cannot be combined with another lower-limb evaluation, and any relied-upon walking aid must be a permanent requirement.

Does knee or hip pain establish arthritis impairment?

No. The arthritis method requires appropriate radiological cartilage-loss measurement. For the knee, only the most impaired compartment is used, and that result is not added to gait, atrophy, strength or ROM for the same joint.

Can atrophy, muscle weakness and nerve loss all be added?

Not where they measure the same loss. The report must apply the NSW non-combination rules and explain why each method is used. A named-nerve deficit is not duplicated through atrophy, manual strength, gait or movement caused solely by that nerve lesion.

Can daily activity problems change the lower-limb WPI?

No. NSW Guidelines paragraph 1.24 says activities of daily living must not alter the calculated lower-extremity rating. They can explain practical impact but are not an extra percentage.

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.

Published by NSW Work Injury Claim, the workers compensation service of Stephen Young Lawyers.

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.

Start free claim check Call (02) 7233 3661

Hip, knee, leg, ankle and foot impairment assessment