## 3 Discussion  
An ACR is a reliable surgical procedure clinically performed in patients with persistent shoulder stiffness. However, the occurrence of osteonecrosis of the humeral head after arthroscopic surgery reflects critical damage to the shoulder joint, necessitating revision surgery [4]. The case presented here involved a patient with predisposing risk factors for osteonecrosis, including a history of chronic alcohol consumption, repeated intra-articular glucocorticoid injections, and previous shoulder surgery. Figure 4: (**A**). Postoperative plain radiograph obtained 21 months post-ACR. (**B**). Oblique coronal T1 fat-suppressed MRI. (**C**). Oblique coronal T2 fat-suppressed MRI shows osteolytic changes in the superomedial humoral head. MRI shows cystic changes in the epiphyseal area, but articular congruity remains preserved. Figure 5: Anteriorposterior radiograph of the shoulder shows articular collapse on the superomedial side of the humeral head at 3-year post-operation. In previous clinical studies, recurrent stiffness and axillary nerve injury have been reported as complications of an ACR [10]. However, postoperative osteonecrosis has not been documented. [PERSON] et al. hypothesized that associated surgical injuries could be caused by knots, the position of the suture anchor at the greater tuberosity or biceps, and the aggressive use of a radiofrequency ablation device [7]. [PERSON] et al. demonstrated that the use of metal or multiple anchors placed at the greater tuberosity injures the anterolateral branch of the anterior circumflex humeral artery (ACHA) [8]. Damage to the arcuate artery can cause osteonecrosis of the humeral head in patients undergoing biceps tenodesis or tenotomy [11]. In our case, the use of radiofrequency ablation may have been associated with the development of osteonecrosis. Circulation to the humeral head is facilitated by anastomoses involving the ACHA, posterior circumflex humeral artery (PCHA), and thoracoacromial artery [9]. The superomedial aspect of the humeral head is particularly prone to osteonecrosis because of compromised arterial perfusion from the interosseous artery, a branch of the ACHA [8]. Given that our patient had undergone previous surgery for acromioclavicular joint dislocation, an iatrogenic injury to the thoracoacromial artery may have occurred [4]. A pseudoaneurysm involving the acromial branch of the thoracoacromial artery near the anterior portal was reported during an arthroscopic rotator cuff repair [4]. Potential injuries to the thoracoacromial artery and ACHA can occur during plate fixation or arthroscopic procedures. Recent research has demonstrated that the PCHA contributes significantly to the blood supply to the interosseous artery of the humeral head [5; 12]. Although the PCHA may remain functional, the combined effects of intra-articular glucocorticoid injections and alcohol consumption may have critical effects, as detailed below. Alcohol induces lipid deposition in osteocytes, increases adipogenesis, and decreases osteogenesis [13]. Alcohol consumption has time- and dose-dependent effects on osteonecrosis [13; 14]. Another clinical study showed that the occurrence of osteonecrosis was associated with a weekly ethanol consumption of \(>\)320 g per week for more than 6 months [13; 14]. In this case report, the patient's consistent alcohol consumption of 40 g \(\geq\)five times per week for 25 years, a time-dependent factor, may have contributed to the development of osteonecrosis. Although hepatitis B is not recognized as a risk factor, its impact on bone quality is notable in the context of liver cirrhosis [13]. The complications of intra-articular steroid injections include septic arthritis, corticosterotid flares, elevated blood glucose levels, tendon rupture, chorioretinopathy, osteonecrosis, chondrocyte, and skin changes [11].