Presentation
Known right shoulder arthroplasty. Recent fall and ongoing pain and limitation of motion.
Patient Data
There is a cemented, reverse, right shoulder, total arthroplasty with posterosuperior dislocation of the humeral stem in relation to the glenoid sphere. There is no periprosthetic lucency, intact prosthesis otherwise, with background bony osteopenia, and acromioclavicular degeneration.
There is known colon carcinoma and the tip of the left chemo port is just visible.
There is an overlying clothing artefact and the embroidered description says "DANGER".
Case Discussion
This is a companion case to rID 152014.
This patient has an unusual history of having two arthroplasty dislocations, initially the right shoulder and subsequently the right hip(rID 152014), 5 years apart. There is a background colon carcinoma, however, no obvious bony metastases are noted in the above views and the patient remains in remission.
The case demonstrates the need for multiple or tangential views to fully exclude joint and prosthetic dislocations or subluxations. In the instance of the right shoulder, one can easily be fooled into thinking the prosthesis is non-dislocated or non-subluxed by just reviewing the lateral series and not realizing that this is a reverse shoulder arthroplasty and the humeral stem should be slightly inferior(and slightly lateral) to the glenoid sphere and not superior to it. The supine anteroposterior right shoulder series also suggests a posterosuperior dislocation.