Deformity Analysis and Osteotomy Planning

IMAGING PLANE

Each plane has its own image, landmarks and calibration.

PATIENT SIDE

Right/left refers to the patient, not the position on screen.

WORK SCOPE

Axis selectionAnatomical axis: the line joining two diaphyseal section midpoints. In a curved bone, this represents only the selected segment.

Length Calibration

Mark both endpoints of a known length in the image plane.

Reference length (mm)

No calibration · distances in pixels

Show Calibration Landmarks

Mose Circles

ⓘ

Used to determine the center from the femoral head contour.

Edit Circles

Circle radius (px)Circle spacing: 5% of the radius (uncalibrated). Changing the radius preserves the center position.

Femoral head centerPending

Distal femoral centerPending

Proximal tibial centerPending

Talar / ankle centerPending

Anatomical Landmarks

Normal / Reference Axes

Bone

MPTA (°)LDTA (°)

The proximal axis is drawn from the MPTA target and the distal axis from the LDTA target.Targets are adjustable. A single CORA may not be sufficient for multilevel deformity.

Drop your radiograph into the workspace.

Drop or upload a PNG, JPG or single-frame DICOM image to begin.
The image should include the hip, knee and ankle.

Files are not uploaded; processing takes place on this device.

Precision ZoomContrast Brightness

MEASUREMENT RESULTS

Right & left comparison

Measurement	Right	Left
mLDFA	—	—
MPTA	—	—
LDTA	—	—
JLCA	—	—
MADpx	—	—

JLCA is the unsigned acute angle between the two joint lines. No result is calculated for missing or coincident landmarks.

Drawing Elements / Appearance

Global Annotation Font Size

Points

Common point settings

Point sizeOpacityShow point names

General measurements

Select Distance, Free Angle, Free Cobb or Line on the image toolbar.

Measurement Method and References

mLDFA: the lateral angle between the femoral mechanical axis and distal femoral joint line. MPTA: the medial angle between the tibial mechanical axis and plateau line. LDTA: the lateral angle between the tibial axis and plafond line. MAD: the perpendicular distance from the tibial knee center to the hip–ankle line; direction describes the mechanical axis medial or lateral to the knee center.

The femoral head center is calculated from three contour landmarks and adjusted with Mose circles. The distal femoral center is the midpoint of the condylar width limits; the proximal tibial center is the midpoint of the plateau width limits; the ankle center is the midpoint of the talar dome limits. These centers are not marked separately. Distal condylar tips and plateau/plafond joint-line landmarks are kept separate for angular measurements. No joint line is drawn between the talar limits. The anatomical axis joins the outer cortical midpoints at proximal and distal diaphyseal sections; purple denotes anatomical and turquoise/blue mechanical axes. CORA is the intersection of the extended selected shaft axes; parallel axes have no finite CORA.

Paley, Principles of Deformity Correction, Chapter 1, pp. 4–6, Figures 1-5 and 1-6. User reference: Doğru Ölçümler, Akslar–Eksenler Nasıl Çizilir? (Correct Measurements, How to Draw Axes?), slides 13, 15, 23.

Paley & Tetsworth, 1992 · uniapical deformity Paley & Pfeil, 2000 · principles of deformity Fragomen et al., 2017 · AP measurement method

Clinical validation is incomplete. Results depend on manual landmarks, radiograph positioning and projection. Three-dimensional rotation is not assessed.

Measurement
mLDFA (°)
MPTA (°)
LDTA (°)
JLCA (°)
MAD (px)

Plane and Image

IMAGE AND CALIBRATION

Upload PNG, JPG or supported single-frame DICOM images. Switching planes preserves AP/PA and lateral workspaces.

Manual Cobb

Start with+ Add Cobbabove the image.Two endpoints of the first endplate → two endpoints of the second. All four can be edited independently; vertebral level selection is optional.

Mark 6–8 or more superior endplates. Their inclinations yield up to three candidates; each requires physician confirmation and a distal endplate. The estimate is not the final Cobb angle.

Advanced Measurements / Balance

Vertebrae and Shared Landmarks

Vertebral numbering must be confirmed by the physician. Clinically verify levels in transitional anatomy; automatic counting is not provided.

VertebraLandmark

General Tools

Distances are displayed in px when calibration is unavailable.

Visibility / Display

Landmark size ·4.5 pxShow AnglesShow Handles

Classifications

Scores and Classifications

Select a measurement or drag an existing landmark handle.

Coronal · AP/PA

Upload a standing full-spine radiograph.
Place the landmarks; lines and results update together.

PNG · JPG · Uncompressed single-frame DICOM

Precision ZoomShow Landmark NamesBrightnessContrastHandles

Global Annotation Font Size

MEASUREMENT RESULTS0

Completed measurements appear here.

Methodology and References

Measurements are calculated from physician-selected landmarks on 2D radiographs. The SRS/SDSG sagittal convention is positive for kyphosis and negative for lordosis. Lordosis is positive for LL magnitude and PI–LL; anterior is positive for SVA and patient right is positive for coronal distances. The physician verifies the 0–180° Cobb branch. In the Cobb construction, perpendiculars to both endplates meet at one vertex; rotating both directions by 90° preserves the angle. The arc represents the calculated branch, not its 90° complement. The drawing does not verify vertebral selection or acquisition quality.

SRS / SDSG · Radiographic Measurement Manual Le Huec et al. · Geometry of pelvic parameters, 2011 Protopsaltis et al. · T1 pelvic angle, 2014

The project ZIP contains 2D source images, landmarks and calculation records. Processed images are stored instead of raw DICOM pixels; pixel coordinates refer to that layer. Original DICOM dimensions, spacing and orientation are preserved separately.

Clinical validation is incomplete. This version does not provide automatic landmark detection, CT rotation assessment or treatment recommendations.

Drop your radiograph into the workspace.

CUTFORT · Deformity analysis report

Manual Multiplanar Analysis

Two planes, one diagram.

Coronal · AP/PA

CUTFORT · Spinal Deformity Analysis