A high incidence of extensor pollicis brevis insertion into the distal phalanx in rheumatoid arthritis patients who required the surgical reconstruction for thumb boutonnière deformity

Objectives: The aim of the current study was to investigate the pattern of extensor pollicis brevis (EPB) insertion macroscopically and histologically using cadaveric thumbs, and to compare the incidence of different insertions with that of thumb boutonnière deformity in rheumatoid arthritis (RA) patients who required surgical reconstruction.Methods: We examined 103 thumbs of 58 adult cadavers with no evidence of RA, and reviewed the surgical...