Extensor pollicis longus tendon rupture as a result of scapholunate dissociation: a case report.

A 39-year-old patient was presented with, to our knowledge, the first ever diagnosed case of extensor pollicis longus (EPL) tendon rupture as a result of scapholunate (S-L) dissociation. Arthroscopic findings showed that the dorsal aspect of the S-L ligament was ruptured and severe synovitis was revealed around the S-L joint. Direct observation revealed synovium at the rupture site of the EPL tendon. After careful resection of this synovium, an aperture in the S-L joint was observed. Thus, it was considered that the synovium in the S-L joint was connected to the rupture site of the EPL tendon, passing through the dorsal capsule of the S-L joint. The ruptured EPL tendon was reconstructed with extensor indicis proprius tendon transfer, and S-L dissociation was treated with a bone-retinaculum-bone autograft taken from the third dorsal compartment region.