Antibiotic-loaded Dissolvable Calcium Sulfate Beads with Cementless TSA for One-stage Revision of Infected Shoulder Arthroplasty

Background:
Treatment of infected shoulder arthroplasty is controversial. To perform single versus two-stage revision is still debatable. Performing two-stage revision involves two surgical procedures, extended damage to the soft tissues and long period of suffering.

The use of antibiotic loaded cement requires the use of cemented implants. Often the use of antibiotic loaded cement beads that require another procedure for removal of the beads.

We introduced a novel technique, using antibiotic-loaded calcium sulfate dissolvable biodegradable beads for single stage revision TSAs with cementless implants.

Aim:
To evaluate the clinical and radiographic outcomes of single stage revision with cementless implants for infected shoulder arthroplasty with the use of these beads.

Design & Methods:
27 patients underwent revision TSA for infection or suspected infection between 2009 – 2020 using antibiotics loaded biodegradable calcium sulfate spheres.

Following removal of the infected implants and meticulous debridement and washout, the biodegradable spheres were inserted into the bones before the re-implantation of cementless new implants. The biodegradable beads were spread in between the soft tissue layers as well.

Demographics, radiographs, and surgery data were prospectively collected. At follow up Constant Score (CS), Subjective Shoulder Value (SSV), range of motion and patient’s satisfaction were recorded. Radiographic analysis was performed in every follow-up.

Results:
Mean age was 66.5 years (50-88 years). Of 27 patients, 25 patients underwent single-stage revision ( 7 TSA to rTSA, 5 resurfacing to rTSA, 3 infected plating to rTSA and 3 resection arthroplasty (post infection) to rTSA).

Only in 2 cases, initial attempt of DAIR (exchange of modular components), one for immediate post-op infection and the other for acute late hematogenic infection failed, and a formal 2-stage revision was successfully performed using the calcium sulfate beads in both cases.

Perioperative cultures grew Propionibacterium acnes; Staphylococcus aureus and Streptococcus Oralis. In some cases, cultures failed to grow an organism, but clinically there was clearly low-grade infection. The follow up ranged from 6 months to 12 years. Infection was successfully eradicated in all, with no recurrence at final follow up. Good function was achieved in all.

On radiographs: all beads resorbed within 3-6 weeks post op. No lucencies around the implants, loosening, subsidence or stress shielding were seen. Good new bone formation was seen were the beads were used to fill bone deficiency.

Conclusion:
The use of dissolvable biodegradable antibiotic-loaded calcium sulfate beads is an effective and practical option in revision TSA for periprosthetic shoulder infections. This new tool enhances our armamentarium and allows us to perform one-stage revision of infected shoulder arthroplasty with Cementless TSA, with excellent outcome and quick recovery for the patient.