Objective To evaluate the open surgical treatment for carpal tunnel syndrome as a risk factor for the development of stenosing tenosynovitis that results in trigger finger and De Quervain disease. Materials and Methods A retrospective study analyzing the medical records of patients submitted to open surgical release of carpal tunnel syndrome between 2010 and 2021 in a secondary- and tertiary-level hospital. The following data were collected: pathological history, duration of the follow-up after the surgical treatment for carpal tunnel syndrome, development of trigger finger or De Quervain tenosynovitis, affected fingers, and the interval between the end of surgery and symptom onset. Results We evaluated 802 patients of both genders and with a mean age of 50.1 (±12.6) years. The mean follow-up was of 13 (±16.4) months. The mean time until the development of trigger finger was of 61.4 months, and of 73.7 months for De Quervain disease. The incidence of development of De Quervain disease was of 4.12%, and for trigger finger it was of 10.2%. The most affected digits were the thumb (47.6%), the middle (24.4%), and the ring finger (8.54%). Age was the only factor that showed an association with the risk of developing trigger finger, with an increase of 2% for each increase in age of 1 year. Conclusion The incidence rates for the development of De Quervain disease (4.12%) and trigger finger (10.2%) after the surgical treatment for carpal tunnel syndrome were like those described in the literature. Only age was a factor that influenced the development of trigger finger.