Higher failure rate of two-stage revision for infected knee arthroplasties in significantly compromised (host-C) patients

Purpose To evaluate clinical outcomes of two-stage revision arthroplasty for managing infected knee arthroplasties in significantly compromised patients (host-C). Methods This was a prospective consecutive series of two-stage revisions of infected total knee arthroplasties in host-C-type patients with a minimum 2-year follow-up using objective and patient-reported outcome measures. Thirteen consecutive patients were included and prospectively followed with a median 5-year follow-up (range 2-10). Median age was 68 years (range 59-73) at time of initial presentation. All patients were type-C host using McPherson classification system. All patients had primary arthroplasties in situ with confirmed chronic infections; the infecting pathogens were Staphylococcus aureus in 5/13 patients, coagulase-negative Staphylococci in 5/13, and the remaining three patients had mixed growth. All patients underwent two-stage revision protocol. Results At the final follow-up, 9/13 patients were infection free achieving satisfactory outcomes. Two patients had recurrent infections with different organisms and treated with suppressive antibiotics and salvage knee arthrodesis, respectively. Furthermore, two patients had chronic pain and poor functional outcomes with deficient extensor mechanism and significant bone loss; later underwent salvage knee arthrodesis. The preoperative knee society score (median 35.5; range 22-51; n = 10) showed a statistically significant improvement at the final follow-up (median 79.5; range 49-87; n = 10) p < 0.05. Patients reported outcome scores at the final follow-up were WOMAC-knee (median 59.1; range 47.7-94.7; n = 13) and Oxford knee score (median 26; range 11 to 43; n = 13). Conclusion This study highlights the challenge of treating infected knee arthroplasties in physiologically compromised patients with 9/13 (69%) having satisfactory clinical outcomes.