Irrigation and Débridement of the Thumb Flexor Sheath for Tenosynovitis—An Anatomic Study for the Optimisation of Surgical Techniques in Cadaveric Specimens

Background: Treatment of a flexor tendon sheath infection of the thumb usually involves prompt surgical irrigation and debridement (ID). There are few descriptions of this procedure despite the unique anatomy of the thumb flexor sheath. The aim of this study was to investigate thumb flexor sheath ID and explore the relevant anatomy. Methods: The current ID technique was performed on eight embalmed cadaveric hands. Coloured latex was injected into the sheath, and the surrounding region was dissected. Outcomes of interest were the distribution of latex, the success of the procedure, and the anatomy of the radial bursa. Results: Latex was successfully injected into all specimens, although A1 pulley stenosis caused significant resistance to flow. Latex filled the radial bursa (four specimens), reached the distal boundary of the transverse carpal ligament (three), or did not pass the A1 pulley (one); in addition, latex was found in the deep spaces of the hand and wrist (five specimens). The radial bursa was located at a median (range) of 33.2 (23.9–34.5) mm proximal to the carpometacarpal joint and at 7.8 (0–14.0) mm distal to the distal border of the pronator quadratus. Conclusion: These findings contribute to the existing body of knowledge on the anatomy of the thumb flexor sheath and radial bursa, and will help guide hand surgeons to perform thorough ID for infection. A modified surgical technique is presented, which may help further inform the treatment of pyogenic flexor tenosynovitis and other serious hand conditions.