Aim: The aim of this retrospective study is to assess the effectiveness of surgical intervention for Kienböck’s disease using 4-5 Extensor Compartmental Artery (4-5 ECA) pedicled osseous flap. Method: Patients who underwent 4-5 ECA pedicled bone grafts for Kienböck’s disease between January 2012 and January 2022 were included in the study. The patient files were analyzed retrospectively for age, gender, follow-up time, and complications. Disease staging was performed preoperatively using direct X-ray and MRI, and radiological improvement was evaluated postoperatively using radiography. The functional and clinical assessment was made by comparing preoperative and postoperative VAS, Q-Dash, and Mayo scores. Results: This study included 23 patients (12 female and 11 male) with Kienböck’s disease who underwent 4-5 ECA pedicled bone graft surgery. 13 cases were right side-left side handed while 10 were left-handed. The mean age was 37.5 ± 12.5 years, and the mean follow-up time was 68 months. The mean preoperative Q-Dash score was 78.8 (± 9), the VAS score was 6.5 (±1.2, and the Mayo wrist score was 34.34 (±11.8). The mean postoperative Q-Dash score was 33.1(±10), the VAS score was 2.4 (±1.7), and the Mayo wrist score was 73.9 (±14.5). The differences between preoperative and postoperative Q-DASH scores (p<0.05), VAS scores (p<0.05), and Mayo wrist scores (p<0.05) were statistically significantly improved. Disease progression was observed in only two patients based on the Lichtman Classification in their follow-up radiographs. Conclusion: Our study demonstrates that the surgical treatment of Kienböck’s disease using a 4-5 ECA pedicled osseous flap is a reliable and effective surgical treatment option.