Knee fracture
Tibial plateau fracture after a motor accident
A tibial plateau fracture extends into the weight-bearing surface of the knee. WPI is not fixed by the fracture label, fixation or number of screws: the assessor identifies the permanent fracture residual, movement, arthritis and any genuinely separate ligament injury.
Motor accident injury
How can this injury happen?
Car or passenger collision
Dashboard or footwell loading can drive the femur into the tibial plateau, producing split, depression or bicondylar fracture.
Motorcycle accident
A motorcycle fall can create axial loading, twisting or direct impact with associated meniscus or ligament injury.
Pedestrian or cyclist impact
Bumper impact can fracture the plateau before the person falls, sometimes adding collateral ligament injury.
Injuries that can occur
- split, depression or bicondylar tibial plateau fracture
- articular surface depression, malunion or alignment change
- associated MCL, LCL, cruciate or meniscus injury
- post-traumatic cartilage loss, stiffness or nerve injury
- compartment syndrome or fixation complications
Symptoms and functional problems
- difficulty weight bearing and reduced walking tolerance
- loss of knee flexion or extension
- instability, swelling or mechanical symptoms
- pain with stairs, squatting or uneven ground
Seek urgent medical assessment
A tense swollen leg, escalating pain, numbness, weakness, absent pulse or suspected compartment syndrome requires emergency assessment.
Clinical evidence
What findings matter?
The file should describe the original fracture pattern and the stable residual. Current alignment, articular congruity, active movement, stability and properly positioned cartilage imaging matter more than hardware alone.
| Record or examination | What it may establish | What it cannot prove alone |
|---|---|---|
| CT and serial X-rays | Define fracture pattern, depression, alignment, union, hardware and later cartilage interval. | Fracture complexity or hardware count does not itself set WPI. |
| Active knee ROM | Records permanent flexion and extension loss under Table 41. | Pain-limited or passive movement is not the impairment calculation. |
| Ligament and neurological examination | Identifies separate residual MCL/LCL/cruciate laxity or nerve injury. | Instability complaints without reproducible findings are insufficient. |
Movement in daily life
How movement affects real activities
Plateau injury can limit flexion for sitting and stairs, extension for stable walking, and tolerance for sustained loading. These functions should be connected to reliable measurements rather than pain descriptions alone.
Knee flexion
Sitting, stairs, kneeling and entering a car.
Table 41 may apply where active flexion loss is the specific residual.
Knee extension
Stable standing, heel strike and efficient walking.
A fixed active extension deficit must be measured consistently.
Alignment and stability
Weight bearing, direction change and uneven ground.
A diagnosis-based residual or separate ligament method may apply if the exact criteria are met.
Threshold injury is a separate question: a verified fracture is not a soft tissue injury and may be non-threshold. WPI remains a separate assessment of permanent impairment.
Part 6 permanent impairment
How is CTP WPI assessed?
Possible methods include Table 64 diagnosis-based estimates, Table 41 active ROM and Table 62 arthritis. Clause 6.71 expressly says a tibial plateau fracture and separate MCL laxity are assessed separately and their WPI values combined.
Measurement rules that apply
- Clauses 6.69 and 6.70 require the method that most specifically addresses the lower-limb impairment. Gait should not replace a joint, nerve, fracture or replacement method that can be applied reliably.
- Clause 6.84 requires active range of motion, a goniometer where clinically indicated and consistent repetitions when reliability is uncertain. Passive movement may inform the examination but does not set the impairment value.
- Clause 6.85 says only the most severe deficit in one direction or axis from the same lower-limb ROM table is rated. Deficits from separate tables may be combined only as the Guidelines permit.
| Method | CTP source | When it is relevant | Important limit |
|---|---|---|---|
| Diagnosis-based fracture estimate | Clauses 6.94-6.97; AMA4 Table 64 | A listed plateau fracture residual with required signs. | Exact row values require a readable AMA4 Chapter 3 table. |
| Knee active ROM | Clauses 6.84-6.85; Table 41 | Reliable permanent flexion or extension loss. | Do not duplicate the same fracture consequence under Table 64. |
| Post-traumatic arthritis | Clauses 6.88-6.92; Table 62 | Measurable articular cartilage interval on properly positioned radiographs. | Cannot combine with ROM, gait, atrophy or strength. |
- Clause 6.71 permits separate assessment of plateau fracture and distinct MCL laxity.
- Use the most specific valid method for each separate impairment.
- Convert any lower-extremity impairment through Table 6.4.
What cannot be combined?
- arthritis with ROM, gait, atrophy or strength
- gait with any other lower-limb evaluation
- fracture and ROM methods for the same residual loss
What does not establish WPI by itself?
- fracture classification alone
- plates or screws
- pain and swelling
- post-operative X-ray without functional findings
Motor accident examples
Depressed plateau fracture with stiffness
The assessor selects the most specific valid fracture or active-ROM method; fixation does not add a separate value.
Plateau fracture with residual MCL laxity
Clause 6.71 allows the genuinely separate fracture and MCL impairments to be assessed before WPI combination.
Claim file preparation
Evidence checklist
Assessment source
Tibial plateau fracture WPI source
Assessment source: Motor Accident Guidelines v10.1 clauses 6.68-6.75, 6.84-6.97 and 6.71; AMA4 Tables 41, 62 and 64; Guidelines Tables 6.4 and 6.5.
Threshold injury: A verified tibial plateau fracture may be non-threshold; WPI is assessed separately under Part 6.
What the assessor checks
- separate fracture and MCL rule
- active ROM
- arthritis radiology
- diagnosis-based estimate
What does not establish the result by itself
- hardware
- pain
- fracture label
- surgery
Official sources
Related NSW CTP guides
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Frequently asked questions
- Does a tibial plateau fracture have fixed WPI?
- No. The assessor applies the most specific valid method to the permanent residual.
- Can a separate MCL injury be added?
- Clause 6.71 expressly permits separate assessment of a plateau fracture and distinct MCL laxity before WPI combination.
- Do plates and screws increase WPI?
- Not by themselves. They document treatment, not a separate impairment.
- How is post-traumatic arthritis assessed?
- Table 62 uses the articular cartilage interval on properly positioned radiographs.
- Can arthritis and knee ROM be combined?
- No. Clause 6.91 prohibits combining the arthritis method with ROM.