An active 34 year old man presented with pain and limited function of his right shoulder and the x-rays shown below.
After which he returned to full comfortable function for 13 years.
However at 14 years after his ream and run, he presented with a 9 month history of unexplained pain and stiffness of his shoulder. His x-rays at that time were unremarkable, showing no evidence of glenoid wear, erosion, loosening or adaptive changes.
His shoulder was stiff, but not tender or swollen. His white cell count and differential, sedimentation rate, and C reactive protein were all normal. A joint aspiration was not attempted.
He elected a revision surgery with soft issue releases and head exchange. The stem was well fixed; it was scrubbed, but not exchanged. There was minimal joint fluid. A frozen section showed only giant cell reaction and fibrous tissue without neutrophils. Deep tissue specimens and the head explant were sent for aerobic and anaerobic culture. The wound was throughly debrided and irrigated with Betadine and saline; topical vancomycin was applied. After his revision, he was placed on oral Doxycycline.
Three weeks after surgery, his culture results were finalized, documenting a periprosthetic infection:
Joint fluid: No growth
Head explant: 1+ Cutibacterium
Collar membrane: 1+ Cutibacterium
Humeral bone: 1+ Cutibacterium
Biceps tendon: 1+ Cutibacterium
His oral Doxycycline was extended for a total of 12 weeks.
He subsequently made an excellent recovery of comfort and function.
Comment: This case is of interest for serveral reasons: (1) the appearance of a Cutibacterium PJI after a honeymoon of over a decade with excellent shoulder function leaves open the question of the source of these bacteria (were they introduced at the original surgery or did they become introduced later?). (2) the joint fluid did not grow bacteria, while all of the deep tissue and explant cultures did (suggesting that the bacteria were not planktonic, but were in biofilms on tissue and metal – a preoperative fluid aspiration would have been falsely negative). (3) the blood work and the frozen section did not suggest infection (suggesting the value of taking cultures at the time of all revisions, performing a thorough debridement and irrigation, applying topical antibiotics and keeping the patient on oral antibiotics until the results are known). (4) the well fixed stem was left in place to avoid the risk of fracture (only time will tell if the retained stem will give risk to recurrent infection).
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