Introduction: Treatment of infected shoulder arthroplasty is still controversial.
This study aimed to evaluate the clinical and radiographic outcomes of revision surgery for infected shoulder arthroplasty with the use of implantable antibiotic-loaded biodegradable beads.
Methods: 5 patients were treated between 2010 – 2017 with revision to reverse total shoulder arthroplasty (rTSA) for periprosthetic shoulder infection using biodegradable calcium sulfate spheres (StimulanÒ, Biocomposites Ltd., Staffordshire, UK), mixed with bacteria specific antibiotics. Following removal of the infected implants and meticulous debridement and washout, the biodegradable spheres were inserted inside the bones before the re-insertion and spread in all tissue layers.
Mean patient age was 68 years (range, 55-78 years). Two patients underwent one-stage revision, one from stemmed anatomic TSA to stemless rTSA, and one from resurfacing to stemless rTSA. Two patients underwent single stage revision from resection arthroplasty (due to infected arthroplasty) to reverse shoulder prosthesis. In one case, initially a one-stage exchange of modular components was attempted but the infection reoccurred, therefore a formal 2-stage revision was performed. Perioperative cultures grew Propionibacterium acnes in 2 cases, Staphylococcus aureus in another 2 cases, whereas in one case cultures failed to demonstrate the presence of any causative organism. Mean follow up was 31.8 months with minimum of 12 months (12m to 63m). Patients were evaluated clinically and radiographically.
Results: In all the patients the infection was successfully eradicated, with no evidence of recurrence. Good function was achieved in all the patients. Mean Constant score improved from 37 before surgery to 71 after surgery (p=0.0006). Active movements improved significantly with forward elevation increased from 78o to 134o (p=0.013); abduction from 74o to 128o (p=0.025); Active external rotation from 31o to 38o (p=0.585). Radiographs at final follow up showed no lucencies around the implants, no evidence of loosening, subsidence or stress shielding.
Conclusion: The use of biodegradable antibiotic-loaded calcium sulfate beads is an effective and practical option in revision surgery for periprosthetic shoulder infections.