## 2 Case Report  
A 56-year-old male patient complained of severe ROM limitations and pain in his right shoulder joint that did not improve. He had a history of a dislocation of the right acromiolacvular joint due to a fall 9 months previously and had undergone open reduction and internal fixation of the joint using a hook plate at another hospital, followed by hardware removal 4 months after the initial surgery. Six months after the removal of the hook plate, he saw no improvement in the persistent stiffness or pain in his shoulder, despite appropriate rehabilitation protocols, including the use of Celebrex oral nonsteroidal anti-inflammatory drugs and physiotherapy. The patient had a history of consuming 40 g of alcohol \(\geq\)five times per week for 25 years but had no history of smoking. He was regularly monitored for chronic hepatitis B and was taking medications for primary hypertension. A postoperative scar was observed on the superior aspect along the distal clavicle and acromion, without definite tenderness, swelling, or redness. Preoperatively, the ROM of the affected shoulder was 90\({}^{\circ}\) for active forward flexion, 90\({}^{\circ}\) for abduction, 40\({}^{\circ}\) for external rotation, and at a sacral level for internal rotation. The passive and active ranges of motion were identical, attributed to the predominant cause of pain being stiffness rather than weakness. The visual analog scale (VAS) score was 4, the American Shoulder and Elbow Surgeons (ASES) score was 51, and the Constant-Murley Score (CMS) was 48. Preoperative shoulder radiographs showed acceptable alignment and joint congruency, with no bony spurs or subchondral lesions. The anteroposterior and axillary views of the shoulder radiograph showed an acceptable status of acromiolacvular joint reduction without arthritic changes. Magnetic resonance imaging (MRI) showed incomplete signal changes in the supraspinatus tendon, without a bony structural abnormality (Figure 1). Given the patient's persistent symptoms, which did not improve, the patient opted for an ACR with informed consent. The ACR was performed in the lateral decubitus position under general anesthesia. The fluid used during the surgery was mixed with 1 mg of epinephrine per 3 L of normal saline, and the water pressure was maintained at 30-50 mmHg using an automatic infuser (10 K Fluid System, ConMed Linvatec, Largo, FL, USA). No abnormalities were observed in the rotator cuff, biceps long-head tendon, or glenohumeral joints upon arthroscopic examination. The ACR was performed according to the regular sequence, starting with the release of the rotator interval, middle glenohumeral ligament, and inferior and posterior capsules using a 3.0 mm 90\({}^{\circ}\) electrocautery device (Arthrocare, Smith & Nephew, Memphis, TN, USA) (Figure 2). After the ACR, the ROM under general anesthesia was defined as 150\({}^{\circ}\) forward flexion, 150\({}^{\circ}\) abduction, at the level of the eighth thoracic vertebral body for internal rotation, and 80\({}^{\circ}\) external rotation. Figure 1: (**A**). Preoperative plain anteroposterior radiograph. Acromioclavicular joint alignment was acceptable with no arthritic changes. The glenohumeral joint showed adequate joint space and congruency. (**B**). Oblique coronal T2 fat-suppressed magnetic resonance imaging (MRI). MRI of the right shoulder showed a thickened axillary pouch with normal hypointense joint capsule. The supraspinatus tendon had high signal variation with intact continuity. Figure 2: Arthroscopic capsular release was performed. (**A**). Release of the thickened middle glenohumeral ligament was performed. (**B**). The inferior capsule was released using a radiofrequency ablation device. (**C**). Engagement synovitis and capsule thickening were observed. At 6-month post-operation, the functional outcomes were reported as a VAS score of 2, an ASES score of 79, and a CMS score of 75.