Trigger wrist caused by avascular necrosis of the capitate: a case report

Background: Trigger wrist is a rare condition first described by Marti in 1960, and various causes have been reported. The condition mostly occurs with finger flexion and extension, and rarely with flexion and extension of the wrist itself. Avascular necrosis of the capitate is also a rare condition, first described by Jonsson in 1942. While some reports of this condition have been published, little is known about its etiology. Therefore, no established treatment exists. We report a case of trigger wrist caused by avascular necrosis of the capitate. Case presentation: A 16-year-old right-handed male who was a high school handball player was referred to our department from a nearby hospital 5 months after the onset of pain in the dorsal aspect of the right wrist, with an unknown cause. At the previous hospital, imaging findings led to a diagnosis of avascular necrosis of the capitate, and conservative treatment with a wrist brace did not improve the pain. At the initial visit to our department, the patient was noted to have a painful trigger wrist that was brought on by wrist flexion and extension. Preoperative imaging findings led to a diagnosis of trigger wrist caused by capitolunate instability secondary to avascular necrosis of the capitate. We performed a partial excision of the proximal capitate with tendon ball interposition. Two years after surgery, the patient's clinical outcome was favorable, with no recurrence of wrist pain or triggering. Conclusions: Both trigger wrist and avascular necrosis of the capitate are rare disorders. When a patient presents with painful triggering at the wrist, surgeons must bear in mind that avascular necrosis of the capitate may result in this phenomenon. We recommend partial excision of the proximal capitate with tendon ball interposition for the treatment of this lesion.