Genu Varus and Valgus Quantification

Purpose

Assess presence and quantify degree of genu varus or valgus

Tag(s)

Limb length, leg length, discrepancy, lower extremity, scanogram

Panel

Musculoskeletal Panel

Define-AI ID

19050030

Originator

David Sandman
Lead David Sandman

Panel Chair

Jay Patti

Panel Reviewers

Musculoskeletal Panel

License

Creative Commons 4.0 
Status Public Commenting
RadElement Set RDES106
                               

Clinical Implementation


Value Proposition


Malalignment of the knee, either genu varus or valgus, can have clinical implications in both the pediatric and adult populations. Measuring the lower extremity alignment can be a tedious, time-consuming task and prone to both intra-reader and inter-reader variability. Automated measurements of the lower extremities can provide an accurate and reproducible measuring technique and result.

Narrative(s)


65 year old male with severe lateral compartment osteoarthritis of the left knee. Total knee arthroplasty is planned, goals of which include attaining physiologic alignment. Weightbearing long-leg/lower extremity radiographs are ordered as part of the preoperative work-up. An algorithm measures the alignment at the knee, auto-populating the data when a radiologist or other clinician reviews the study.

Workflow Description


Images obtained from the radiography unit are sent to PACS and the AI engine. The images are analyzed by AI. Coordinates of areas of interest are assessed using a measuring tool. Annotated measurements are saved as an image along with a summary of the measurement data set.


Considerations for Dataset Development



Procedures(s)

{Standing/weightbearing long-leg/lower extremity radiographs}

View(s)

{Upright/standing-radiographs}

Sex at Birth

{Male,Female}

Age

[0,90]

Technical Specifications


Inputs

 

DICOM Study

Procedure

Standing/weightbearing long-leg/lower extremity radiographs

Views

AP Views

Data Type

DICOM

Modality

Radiograph

Body Region

Lower Extremity

Anatomic Focus

Hip, thigh, knee, leg , ankle



Primary Outputs


Bilateral qualitative alignment of the knee


RadElement ID

RDE686

Definition

Genu varus, valgus or normal alignment.

Mechanical axis (MA) = line from top of femoral head to mid tibial plafond. If MA medial to intercondylar notch = genu varus.

If MA lateral to intercondylar notch = genu valgus.

If MA within the intercondylar notch = normal alignment.

Data Type

Categorical

Value Set

  • Unknown
  • Normal alignment
  • Genu varus
  • Genu valgus

Units

N/A



Bilateral quantitative alignment of the knee


RadElement ID

RDE684

Definition

Measure genu varus or valgus.

1) Mechanical axis of femur (MAF) = line from top of femoral head through intercondylar notch

2) Tibial axis (TA) = line from intercondylar eminence to mid tibial plafond

3) Angle between continuation of MAF to level of tibia and TA

Data Type

Numeric

Value Set

N/A

Units

Degrees