Knee model from an MRI

An interactive, self-contained model of a left knee, driven by an MRI report. It shows what the kneecap, cartilage and tendons do during walking, running, cycling, home exercises and gym lifts, and lays out a 6-week marathon plan.

Live page: https://saadsaifse.github.io/knee-model-mri/ (dark theme: knee-model.html)

Educational model, not medical advice. The drawings are schematic, not traced from the scan, and the numbers come from published averages (Huberti & Hayes contact areas, a pulley model of the kneecap, a lateral shift calibrated to the MRI). Talk to your physio or doctor before acting on it.

MRI findings modelled

• Mild lateral patellar subluxation (0.8 cm), TT-TG 1.7 cm
• Trace chondromalacia with a tiny full-thickness cartilage defect and subchondral edema on the lateral patellar facet
• Mild quadriceps and patellar tendinosis
• Medial meniscus extrusion without a tear, and a subcentimetre Baker's cyst

Screenshots

Fig 1: patella tracking bench. The kneecap rides in its groove as the knee bends. A gauge reads the outward shift and the stress on the outer facet.

Fig 2: one running stride. A treadmill runner, with the knee shown from the side, from the front and in a cross-section slice. Every view moves with the stride.

Fig 3: cycling saddle height, and Fig 12: single-leg hip thrust (one of 13 figures)

Every figure has hover, a slider and play/pause.

Files

index.html is the page: knee-model-light.html, served on GitHub Pages. knee-model.html is the dark theme. Every html file is standalone, so you can open it straight in a browser.

Earlier drafts are kept for reference: knee.html (walking, running, home exercises), knee-v2.html (adds cycling, gym, cartilage and the marathon) and knee-v3.html (adds the anatomy views and the running stride), each with a -light twin.

Rebuilding

You need Node 18+ and no packages.

node build-v3.mjs --page          # knee-model.html
node build-v3.mjs --page --light  # knee-model-light.html and index.html

• model.mjs holds the biomechanics: quad force, the force between the kneecap and the femur, contact area, lateral shift and facet stress. Every number shown on the pages comes from it.
• bench.mjs, mannequin.mjs, gym.mjs, exercises.mjs and anatomy-knee.mjs hold the geometry and figures.
• page/ holds the prose. v2/ and v3/ hold the prose for the earlier drafts, built without --page.
• vendor/anatomy/ is the isometric drawing kit (MIT, see its LICENSE).