Saturday, February 6, 2016

Periprosthetic shoulder arthroplasty infection - management with exchange arthroplasty

The authors conducted a systematic review comparing the infection eradication rate and functional outcomes after single- or two-stage shoulder exchange arthroplasty with those for permanent spacer implant or resection arthroplasty. They included 8 original articles reporting the results after resection arthroplasty (n = 83), 6 on single-stage exchange (n = 75), 13 on two-stage exchange (n = 142) and 8 papers on permanent spacer (n = 68).

The average infection eradication rate was
86.7 % at a mean follow-up of 39.8 months (SD 20.8) after resection arthroplasty, 
94.7 % at 46.8 months (SD 17.6) after a single-stage exchange, 
90.8 % at 37.9 months (SD 12.8) after two-stage exchange, and 
95.6 % at 31.0 months (SD 9.8) following a permanent spacer implant. 

The difference was not statistically significant (p = 0.650).

Constant scores were
mean 51, SD 13 for patients with single-stage exchange
mean 44, SD 9 for patients undergoing a two-stage exchange (mean 44, SD 9), 
mean 32, SD 7 for resection arthroplasty and
mean 31, SD 9 for permanent spacer implants

Comment: The authors pointed out that this systematic review failed to demonstrate a clear difference in infection eradication and functional improvement between the four treatment modalities for established periprosthetic shoulder infection because of the relatively low number of patients and the methodological limitations of the studies. 

This report does not include some critical data (1) the bacteria responsible for the infections, (2) the details of the single stage exchange (e.g. conversion of a total shoulder to a hemiarthroplasty or to another total shoulder), (3) the antibiotic regimen used, or (4) the way in which 'irradiation of infection' was determined.

Nevertheless, the lack of clear advantage of the more radical approaches (two stage, resection, or permanent spacer), leads us to consider single-stage exchange in most cases.