Purpose: Osteotomies around the knee have been established as an effective method for treating varus or valgus malalignment associated with other knee pathologies in young and middle-aged patients. There is limited literature regarding the risks and complications based on patient age. The purpose of this study is to determine whether age influences as a risk factor for developing intraoperative and early post-operative complications in patients undergoing osteotomies around the knee. Methods: A consecutive series of patients over 18 years old who underwent distal femoral osteotomy (DFO) or high tibial osteotomy (HTO) with a minimum follow-up period of 90 days were included. Demographic characteristics, surgical technique, intraoperative and post-operative complications up to 90 days were identified. A statistical comparison based on age younger than 55 years or 55 years and older was conducted to determine if patient age acted as a risk factor in the development of complications. Results: A total of 159 osteotomies were included, of which 129 were HTOs. The average age was 46.16 years, and 118 patients were younger than 55 years. Seven hinge fractures were identified as the only intraoperative complication, while the overall early post-operative complication rate was 11.32%. The most frequent was deep venous thrombosis (DVT) in 5.66% of cases, followed by deep infection with a total rate of 2.52%. When performing the subgroup analysis by age, we observed a significantly higher rate of DVT in the group aged 55 years and older (p 0.036) (odds ratio 3.96 95% confidence interval 1.009–15.533; p 0.048); however, no significant differences were observed in the overall complication rate according to the age group of the patients. Conclusions: This study reveals that in patients undergoing osteotomies around the knee, the most common post-operative complication was DVT. The rate of DVT was significantly higher in patients aged 55 years and older, although no differences were observed in the overall complication rate according to the patients' age range. Level of evidence: Level III (retrospective cohort study).