Cuptomize
Functional THA cup planning · no patient data leaves your browser
Spinopelvic measurement (beta) — derive SS / PT / PI from a lateral film

Pick the posture, then upload that film — each of the four (preop/postop × standing/sitting) keeps its own image, so you can measure all of them. The S1 endplate and femoral head are auto-detected; verify by dragging — SS / PT / PI update live. S1 endplate: 2 points along the sacral (S1) superior endplate. Femoral head: 1–2 points at the femoral-head centre(s) — on a true lateral the heads overlap. Computed so PI = SS + PT. Local only.

Load a lateral film to begin.
Definitions & diagrams — what each abbreviation means

Tap the ⓘ next to any field or result for an inline definition and diagram. Full glossary below.

Image measurement (beta) — derive RI / RA / cup size from a radiograph

Upload an AP pelvis image: the cup is auto-detected and a default teardrop line is placed. Verify by dragging any point — RI / RA update live. Cup rim: ≥5 points around the ellipse. Teardrops: drag the 2 points onto the teardrops. Marker: 2 points spanning the 25 mm sphere (optional, for cup size). All processing is local.

Load an image to begin.
AP-only pelvic-tilt estimate (no lateral film) — estimate only

Schwarz tilt ratio = lesser-pelvis height / obturator-foramen height (neutral ≈ 0.5). Lesser-pelvis height: vertical distance from the top of the sacroiliac (SI) joints down to the upper border of the pubic symphysis. Obturator-foramen height: the maximum vertical height of one obturator foramen. Upload an AP pelvis and place the 2 points for each (drag to refine), or enter the heights manually. Estimate only — lateral radiographs are required for accurate pelvic tilt. All processing is local.

Postoperative comparison — actual cup vs preoperative targets

Uses the case above as the preoperative plan. Enter the actual postoperative cup orientation and sitting SS to compare against the functional safe zone.

AP pelvis — cup
Leave blank to derive from ellipse a/b.
Standing lateral
Sitting lateral
Risk factors