Differential Diagnosis for Painful Restricted Movement of the Left Shoulder

Single Most Likely Diagnosis

• Osteoarthritis (OA) of the shoulder: This is the most likely diagnosis given the presence of mild to moderate arthritic changes in the glenohumeral and AC joints, which are consistent with OA. The clinical presentation of painful restricted movement also aligns with OA.

Other Likely Diagnoses

• Adhesive Capsulitis (Frozen Shoulder): Although the X-ray does not specifically show signs of adhesive capsulitis, the clinical presentation of painful restricted movement is a hallmark of this condition. It often occurs in the absence of significant radiographic abnormalities.
• Rotator Cuff Tendinopathy or Tear: While the X-ray does not directly show soft tissue injuries, rotator cuff issues are common causes of shoulder pain and restricted movement. These conditions might not be visible on an X-ray but are likely given the clinical context.
• Acromioclavicular (AC) Joint Arthritis: Given the mention of arthritic changes in the AC joint, isolated AC joint arthritis could be a contributing factor to the patient's symptoms.

Do Not Miss Diagnoses

• Septic Arthritis: Although the X-ray does not show signs of an acute bone injury or obvious soft tissue calcification, septic arthritis is a condition that could present with sudden onset of pain and restricted movement. It is crucial to consider this diagnosis due to its potential for serious complications if not promptly treated.
• Fracture (e.g., Stress or Occult Fracture): The report mentions no acute or healing bone injury, but sometimes fractures can be subtle or not immediately visible on X-ray. It's essential to ensure that no fracture is missed, especially if the clinical suspicion remains high.

Rare Diagnoses

• Avascular Necrosis (AVN) of the Humeral Head: This condition could lead to shoulder pain and restricted movement but would typically require additional imaging (like MRI) for diagnosis. It's less likely given the absence of specific risk factors mentioned, but it remains a possibility.
• Polymyalgia Rheumatica (PMR): This inflammatory condition can cause shoulder pain and stiffness, among other symptoms. While it's less directly related to the radiographic findings, it's a systemic condition that could explain the patient's symptoms, especially in the appropriate clinical context.