Radiograhic Evaluation of Congenital and Acquired Foot Deformities: Talo-Calcaneal Angles

Purpose

Characterization of congenital and acquired foot deformities on radiographs  

Tag(s)

bilateral foot, foot, x-rays, radiographs,congenital foot, pes,feet, talo-calcaneal angle, weight-bearing 

Panel

Pediatric

Define-AI ID

20010011

Originator

Pediatrics Panel
Lead Viet Le & Alex Towbin

Panel Chair

Steven Blumer

Panel Reviewers

Pediatric Panel

License

Creative Commons 4.0
Status Public Comment
RadElement Set RDES200 

Clinical Implementation


Value Proposition


Multiple angles and measurements can be used to evaluate abnormal development of the foot, but the task of obtaining these can be cumbersome and time-intensive. An automated method for obtaining a series of angle measurements and bony relationships, which can eventually be used to characterize foot deformities, should improve the radiologists’ workflow.

For this use case(s), the focus will first be placed on automating the measurement of a series of different angles and bony associations on foot radiographs, which can then be compiled to determine the presence vs. absence of a foot deformity. If present, our hope is for the algorithm to further diagnose/characterize the specific foot deformity. Ultimately, this may be expanded to include additional modalities, such as CT.

For this particular use case, we will limit our evaluation to measuring the AP talo-calcaneal angle and the lateral talo-calcaneal angle. Additional use cases include the talonavicular axis, intermetatarsal angle, talo-1st metatarsal angle, calcaneal pitch, 1st metatarsophalangeal angle, Meary’s angle, and the tibial-calcaneal angle.

Narrative(s)


3 year-old female presents to the pediatrician with abnormal gait and in-toeing. Bilateral, weight-bearing 3-view foot radiographs are obtained for evaluation of foot deformities.

6 month-old male presents for contractures/abnormal positioning of the feet. Bilateral, 3-view foot simulated weight-bearing radiographs are obtained for evaluation of foot deformities.


Workflow Description


Radiographs of the foot/feet are ordered, obtained, sent to PACS and the algorithm is triggered.


The algorithm delivers the following outputs: AP talo-calcaneal angle, lateral talo-calcaneal angle, normal vs. increased/decreased angle

Considerations for Dataset Development


Procedures

X-ray, Foot

Radiograph, Foot

Gender

Male, Female

Age (years)

0-18

Views

AP, Lateral

Technique

Erect, Weight-bearing or Simulated weight-bearing

Anatomy

Foot

Confounders

Cast, Splint, Brace, Non-weight-bearing, Supine

Technical Specifications


Inputs

 

DICOM Study

Procedure

X-ray, Foot Radiograph

Views

AP, Lateral

Data Type

DICOM

Modality

X-ray

Body Region

Lower Extremity

Anatomic Focus

Foot


Primary Outputs

 

AP Talo-calcaneal Angle   

RadElement ID

RDE1329 

Definition

The angle between the lines drawn down the axis of the talus and the calcaneus on weight-bearing AP foot radiograph.

Data Type

Numeric

Value Set

0-180

Units

Degrees



Lateral Talo-calcaneal Angle       

RadElement ID

RDE1330 

Definition

The angle formed by the intersection of the line bisecting the talus through the body and through the neck and the line along the axis of the plantar border of the calcaneus (or bisecting the calcaneus) on lateral weight-bearing views.

Data Type

Numeric

Value Set

0-180

Units

Degrees


Secondary Outputs 

 

Normal vs. Decreased vs. Increased AP Talo-calcaneal Angle       

RadElement ID

RDE1331 

Definition

Normal range for the AP talo-calcaneal angle is 30 to 45 degrees.

Data Type

Categorical

Value Set

  • Normal

  • Decreased (<30), hindfoot varus

  • Increased (>45), hindfoot valgus

Units

N/A


Normal vs. Decreased vs. Increased Lateral Talo-calcaneal Angle   

RadElement ID

RDE1332 

Definition

Normal range for the lateral talo-calcaneal angle is 30 to 50 degrees.

Data Type

Categorical

Value Set

  • Normal (35-50)

  • Decreased (<35), hindfoot varus

  • Increased (>50), hindfoot valgus

Units

N/A

Future Development Ideas


As mentioned in the Value Proposition, future development ideas include

  • Additional angle measurements

  • Bony relationships in the foot

  • Diagnosis of foot deformities if present (“diagnostic use cases”)

  • Improvement from prior studies if comparisons are available

  • Extrapolation to another imaging modality, such as CT

  • Detection of post-surgical change e.g. mid foot osteotomies and hardware for correction of malalignment.