Review Question - QID 108971

A 65-year-old man presents to his primary care physician for stiffness in his arm. He has been having trouble combing his hair and reaching objects that are high on the shelf. The patient has a medical history of type 2 diabetes mellitus, obesity, and hypertension. His current medications include metformin, insulin, lisinopril, and hydrochlorothiazide. The patient leads a sedentary life in which he tends to stay home and watch television. He does not engage in any physical or strenuous activity. His temperature is 98.6°F (37°C), blood pressure is 138/85 mmHg, pulse is 75/min, and respirations are 12/min. On physical exam, the patient has decreased passive and active range of motion of his shoulder. The strength of the patient's upper extremity is 4/5 limited by pain. Which of the following is the most likely diagnosis?