Frozen shoulder or shoulder stiffness from Parkinson disease?

PURPOSE: To understand the role of camptocormia (increased kyphosis) and postural alteration in Parkinson's disease in the development of shoulder pathology, with a special concern for adhesive capsulitis and shoulder stiffness. METHODS: A preliminary online search was carried out, with combination of keywords including "Parkinson," "Shoulder stiffness," "Frozen shoulder," "Adhesive capsulitis," "Postural alteration," "Camptocormia". The retrieved papers were screened by title and abstract and those considered relevant to the aim of the review were read in full text and included. Relevant information were extracted and reported into text. RESULTS: Due to a severe impairment of posture, patients affected by PD show an increased thoracic kyphosis (camptocormia) and decreased mobility of the trunk that can yield a humeroacromial impingement syndrome and capsulitis, resulting in inflammation of the bursa, shoulder pain and reduction of movement. Furthermore, kinematic of the shoulder is allowed by the combined movement of the humerus, the scapula, the clavicle, the thoracic wall and thoracic spine. The thoracic spine and wall mobility are severely impaired in the parkinsonian patient, thus limiting the shoulder motion. CONCLUSION: The postural alteration observed in PD is the primum movens for shoulder pathology, since anterior tilt of the scapula, which occurs with the increment of thoracic kyphosis, yields to a subacromial impingement. A closed loop is then created, as the rigidity of the shoulder causes further alteration in the posture, which worsens the impingement syndrome and so on.