Midcarpal instability is a common but infrequently diagnosed cause of chronic wrist pain. The purpose of this project was to develop a treatment algorithm for this condition. 16 wrists (15 patients: 9 female, 6 WCB, average age 27 y) with generalized wrist pain (average duration 24 mo) and a positive provocative test for midcarpal instability were treated with a cast or splint full time for 6-8 weeks +/- antiinflammatory medications. Although all patients obtained at least partial relief with immobilization, significant symptoms quickly returned with mobilization. An anatomically based surgical procedure was developed to achieve ligamentodesis and capsular plication in the four-corner triquetrum-hamate-capitate-lunate region to stabilize the midcarpal joint. Follow-up (av. 8 mo, range 4-15 mo) showed a 37% increase in grip strength, and a significant improvement in wrist scores and patient satisfaction. All patients had decreased pain at follow-up. Functional scores improved in most patients, but 3 remained the same due to decreased range of motion. WCB patients, those who sustained major trauma and had multiple diagnoses in addition to midcarpal instability, had a poorer outcome; instability has recurred in one such patient. To date, this procedure has been highly successful in patients with ligament laxity and a history of minor or repetitive trauma.