Background: Predicting which patients will do well with arthroscopic triangular fibrocartilage complex (TFCC) debridement alone or which patients may benefit from arthroscopic debridement and ulnar shortening at the same time can be challenging. In this retrospective cohort study, we aimed to assess the rate and type of complications and reoperations after arthroscopic TFCC debridement. Furthermore, we aimed to identify factors associated with reoperation and specifically ulnar shortening osteotomy (USO) after this procedure. Methods: We included 163 patients who underwent arthroscopic TFCC debridement as a first surgery for treatment of their ulnar-sided wrist pain. Patient charts were manually reviewed, and ulnar variance was measured on preoperative posteroanterior radiographs of the wrist. Bivariate analysis and multivariable logistic regression analysis were performed to identify factors associated with reoperation. Additional subgroup analyses looking at USO after TFCC debridement were performed with Kaplan-Meier analysis and Cox regression survival analysis. Results: We found a complication rate of 14% and a reoperation rate of 19% (most common USO with 10%). Chondromalacia was independently associated with reoperation. Forty percent of patients with a positive ulnar variance later proceeded to USO. A hazard ratio of 1.8 per millimeter of ulnar variance was found. Conclusions: Our data suggest that patients with a positive ulnar variance with frank chondral loss at the time of arthroscopic TFCC debridement may benefit from simultaneous USO.