Peri-Prosthetic Joint Infection of the Knee Causes High Levels of Psychosocial Distress: A Prospective Cohort Study.

Background: Peri-prosthetic joint infection (PJI) is a major complication of knee arthroplasty that can cause long-term disability. In addition to its physical impact, there is a clear psychological burden that has not been measured yet. We hypothesized that the psychosocial burden of PJI can be assessed quantitatively using standardized questionnaires and may be correlated with treatment stage. Methods: Thirty-one patients were enrolled in this longitudinal prospective cohort study from August 2015 to November 2016. Participants had clinically established knee PJI after primary total knee replacement in osteoarthritis according to the Musculoskeletal Infection Society criteria and underwent a standardized two-stage protocol. After explantation of the prosthesis and implantation of a polymethylmethacrylate knee spacer, patients were treated with organism-specific intravenous antibiotics for two weeks, followed by oral antibiotics for four weeks; and then reimplantation was performed in all cases. Psychometrically validated standardized questionnaires were used to measure psychosocial stress via self-assessment at four time points: (1) Before explantation of the prosthesis; (2) after explantation; (3) after the antibiotic treatment before reimplantation; and (4) three months after reimplantation (follow-up). The Patient Health Questionnaire (PHQ)-4, Short Form (SF)-12 (including PSK and KSK), Questions about Life Satisfaction (FLZM) and Fear of Progression (PA-F-KF) (titles and abbreviations in German) scores were interpreted according to cut-off values for depression, fear of progression, anxiety, and quality of life. Results: Eighteen patients (58.1%) showed a PHQ-4 score above the cut-off value for depression at least once, with the highest score before reimplantation (time point 3). On the SF-12, the mean subtest mental scale (PSK) score was 42.6 (± 14.5), and the mean subtest physical scale (KSK) score was 26.9 (± 7.5) over the four time points, which was significantly lower than that of the general German population (PSK 53.1, KSK 44.0; p < 0.05). The SF-12 scores did not change significantly over time. On the FLZ, health was least satisfactory, followed by recreational activities and work. On the PA-F-KF, patients had the greatest fear of being dependent on outside help, drastic medical interventions, and infection progression. The mean PA-F-KF value was 31.24 (± 9.60; values ≥34 are regarded as critical). Conclusion: Peri-prosthetic joint infection is a measurable, relevant psychosocial stressor for patients. Their quality of life and fear of the disease progressing are comparable to those of oncology patients. Routine screening should be conducted to identify affected patients early for appropriate treatment, improving long-term outcomes. Orthopaedic surgeons who treat patients with PJI should initiate by psychologists as well in order to maintain the patient's long-term quality of life.