CASE A 20-year-old woman presented with painful, snapping extensor pollicis longus (EPL) tendon subluxation and trapeziometacarpal (TMC) joint instability. Hemi-extensor carpi radialis longus (ECRL) tendon autograft stabilized the TMC joint, reconstructing the 1-2 intermetacarpal ligament. The subluxed EPL tendon was centralized over the dorsal first metacarpal by tightening the metacarpophalangeal radial sagittal band and creating a dorsal first metacarpal "neosheath" pulley using ECRL graft remnant. Postoperative rehabilitation included Spica bracing and immediate thumb interphalangeal joint exercises. CONCLUSION The patient's pain due to EPL tendon subluxation and TMC joint instability completely resolved. Postoperative thumb range of motion and function were equivalent to the nonaffected side.
