Surgery Best Option for Open Disclocation of the Thumb Interphalangeal Joint
An open dislocation of the interphalangeal thumb joint (the joint in the middle of the thumb) occurs when there is not only dislocation, but also a wound that exposes the dislocated area. Because of the strength and stability of this thumb joint, this injury isn't common. When doing a search of the medical literature, this is backed up by there being relatively few discussions and descriptions of irreducible dislocation of the joint. Irreducible means the inability to set the joint properly to its pre-injury state.

The authors of this article presented a case of a 32-year-old man who had an open thumb interphalangeal joint dislocation, which was caused by a combination of factors after he twisted and hyperextended his left thumb during an altercation. The thumb had a 2-centimeter cut on top of the joint and his thumb was obviously deformed. The end of the lower bone in the thumb was seen sticking out of the wound. It appeared that the blood circulation was still intact but the patient did say that the top of the thumb felt numb.

The doctors cleaned out the wound and tried to close it using a local anesthetic, which did not work. The patient was then put under a general anesthetic so the surgeon could try to reduce the joint, or put it back into place. This was not successful either so the surgeons extended the wound for a clearer view of the joint and bones. They found that a tendon, the FPL tendon, had moved and was out of place. The surgeons dissected the area and found that the ulnar digital nerve, the nerve that help the thumb move, was wrapped around the end of the bone. The surgeons then untangled the joint and returned it to its natural position alongside the joint. Once this was done, the surgeons could see the volar plate, the "floor" of the joint, which had been jammed into the joint. They were then able to remove the volar plate and the joint then went back into place easily.

The authors wrote that thumb dislocations such as this one can be difficult to treat because of the different structures inside the thumb that can become injured, moved, or trapped when the joint is dislocated. For this reason, surgery is usually the only method that allows for a successful outcome. By opening the thumb further, if necessary, the surgeons may see exactly what is causing the dislocation from being reset and provides room for the area to be corrected.
Samir R. Shah, MD, Randy Bindra, MD, and Justin W. Griffin, BS. Irreducible Dislocation of the Thumb Interphalangeal Joint With Digital Nerve Interposition: Case Report. In Journal of Hand Surgery. March 2010. Vol. 35. No. 3. Pp. 422-424.