To evaluate and compare the clinical and radiographic outcomes of both acute and chronic two-part lesser tuberosity fracture with locked posterior dislocation and analyze the risk factors for the clinical outcomes.Between April 2003 and June 2010, 29 patients received surgical treatment for two-part lesser tuberosity fractures with a locked posterior shoulder dislocation. Eighteen of these patients received modified McLaughlin procedures and were available for both clinical and radiographic evaluation for more than 2 years. All of the 18 patients were male. The average age was (40 ± 11) years (range, 21-58 years). Nine patients had left arms involved while another 9 patients got right side involved, 9 of 18 patients had their dominant side involved. The average time from initial injury to surgery was (40 ± 42)days (range, 4-123 days). The patients received follow-up 3 months, 6 months and 1 year after the operation, and the follow-up was performed once a year. The shoulder range of motion and visual analogue scale (VAS) were recorded at the final follow-up. The functional outcomes were evaluated using University of California-Los Angeles Shoulder Scale (UCLA), Constant Score, and American Shoulder and Elbow Surgeons Shoulder Score (ASES). The degree of humeral head necrosis was analysed according to plain radiographs taken at the final follow-up. The risk factors including patients' age, dominant side involvement and time from injury to surgery on the final clinical outcomes and the degree of humeral head necrosis were also analysed using Pearson correlation analysis and Wilcoxon analysis methods.The mean follow-up period was (38 ± 16) months (range, 24-72 months). All of the patients regained shoulder stability postoperatively. At the final follow-up, the average VAS was 0.6 ± 0.9 (0-3). The average UCLA was 28 ± 4 (23-33). The average Constant was 85 ± 8 (71-96). The average ASES was 83 ± 7 (75-95). The time from injury to surgery was identified as the risk factor regarding UCLA (r = 0.648, P = 0.004), Constant score (r = 0.506, P = 0.032) and ASES score (r = 0.517, P = 0.028).Satisfactory results can be achieved with surgical treatment for lesser tuberosity fractures with locked posterior shoulder dislocations. The time from injury to surgery has a negative impact on the clinical function outcome.