Clinical outcomes of bending versus non-bending of the plate hook in acromioclavicular joint dislocation

BACKGROUND: We aimed to assess the effect of plate hook bending in treatment of acromioclavicular (AC) dislocation by analyzing clinical and radiological results according to the angle of the plate hook (APH). METHODS: This was a retrospective, observational, case-control study including 76 patients with acute AC joint dislocation that were divided into two groups according to treatment with bent or unbent plate hook. The visual analog scale (VAS), the American Shoulder and Elbow Surgeons (ASES) shoulder score, and range of motion (ROM) were evaluated as clinical outcomes. Comparative coracoclavicular distance (CCD) was measured to evaluate radiological outcomes. RESULTS: While the VAS and ASES of the bending group at 4 months after surgery were significantly higher (p=0.021 and p=0.019), the VAS and ASES of the bending group at other periods and ROM of the bending group showed no significant difference. The initial CCD decreased from 183.2%±25.4% to 114.3%±18.9% at the final follow-up in the bending group and decreased from 188.2%±34.4% to 119.1%±16.7% in the non-bending group, with no statistical difference (p=0.613). The changes between the initial and post-metal removal CCD were 60.2%±11.2% and 57.3%±10.4%, respectively, with no statistical difference (p=0.241). The non-bending group showed greater subacromial osteolysis (odds ratio, 3.87). Pearson’s coefficients for the correlation between APH and VAS at 4 months after surgery and for that between APH and ASES at 4 months after surgery were 0.74 and –0.63 (p=0.027 and p=0.032), respectively. CONCLUSIONS: The APH was associated with improved postoperative pain and clinical outcomes before implant removal and with reduced complications; therefore, plate hook bending is more useful clinically during plate implantation.