Shoulder Dysfunction in Parkinson Disease: Review of Clinical, Imaging Findings and Contributing Factors

This study aimed to review shoulder clinical and imaging findings in Parkinson's disease (PD), focusing on the significance of timely diagnosis and management of shoulder dysfunction in PD for the prevention of shoulder-related complications. A bibliographical search was employed, using "Parkinson's" and "Shoulder Dysfunction" as keywords. A Magnetic Resonance Imaging, twenty clinical and three US studies were selected as relevant to shoulder dysfunction in PD. Shoulder pain, frozen shoulder and arm swing asymmetry are the most prevalent clinical findings that may antedate cardinal PD symptoms. Supraspinatus tendon thickening or tearing, adhesive capsulitis, acromioclavicular changes, bursa and joint effusion are common shoulder MRI or US-detected abnormalities in mild or severe PD stages. Fractures due to falls or osteoporosis are secondary shoulder pathologies. Higher ipsilateral Unified Parkinson's Disease Rated Scale (UPDRS) scores, rigidity, tremor, and bradykinesia are associated with frozen shoulder. Disease duration, rigidity, and falls are contributing factors for tendon tears, adhesive capsulitis, and fractures respectively. When common symptoms, such as pain and frozen shoulder are unaccounted for by orthopedic or other local primary pathology, they might indicate underlying early PD. Timely diagnosis and appropriate early management of PD may, in turn, help delay or prevent shoulder-related complications.