Monday, April 17, 2017

After a total shoulder, when is glenoid loosening aseptic?

A man in his mid sixties had a total shoulder for arthritis. Five years afterwards he noted a feeling of instability in his shoulder on active motion. Eight years after the arthroplasty he presented to us for a revision. On exam his shoulder was painful on active and passive motion. A distinct "clunk" could be felt when he flexed his arm. His AP views show a large humeral stem with the head sitting a bit high and perhaps a suspicion of lucency around the glenoid.

His axillary "truth" view showed obvious radiolucent lines around the cement of the keeled glenoid.

At his revision the humeral component was removed; the glenoid was grossly loose. The residual glenoid was smoothed. No glenoid bone grafting was performed. A new humeral component with an anteriorly eccentric humber head was inserted with impaction allografting. The residual glenoid defect is seen on the post operative x-ray.

His culture results, particularly from the glenoid, were positive for Propionibacterium (Cutibacterium) as shown below

Humeral head - 0.1
Humeral stem - no growth
Capsule - no growth
Collar memberane - 1.1
Glenoid cement #1 - 1
Glenoid cement #2 - 1
Glenoid component - 2

He was managed with the red protocol.

Ten months after surgery his shoulder was comfortable and stable, his active range of motion was progressing with PT. His x-rays showed apparent filling-in of the glenoid defect.

Comment: This case suggests the possibility of a Propionibacterium infection localized primarily to the glenoid.  In our practice of revision arthroplasty we usually avoid grafting the glenoid defect. It is of interest that in this case the glenoid surface appears to have reconstituted without grafting.

Our current management of apparently aseptic shoulder arthroplasty failure can be seen in this link


Information about shoulder exercises can be found at this link.

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