COMPARATIVE STUDY OF TISSUE CULTURE AND USE OF ULTRASOUND ON IMPLANTS IN THE DETECTION OF PROSTHETIC INFECTION

Abstract

Introduction and Objectives: Culture of periprosthetic tissue is the diagnostic treatment of reference in prosthetic infection (sensitivity 65–94%). The use of ultrasound to detach microorganisms attached to the implant may increase sensitivity.

Materials and Methods: We prospectively cultured in different media the ultrasound product of the implants (knee prosthesis, hip, osteosynthesis material (OM) and spine plates and screws) extracted in our center and we obtained 3–5 samples of periimplant tissue to cultivate in each case. The gold standard was the presence of pus, fistulas, acute inflammatory tissue in the histological study or presence of positive cultures with clinical concordance. We also assessed the use of antibiotics prior to surgery.

Results: We assessed 153 cases. Infections: 11 hip, 16 knee, 16 OM and 7 spine plates and screws. Conventional technique: there was a sensitivity of: 63% in hip prosthesis, 56% in knee, 81% OM and 71% in spinal plates and screws with a specificity of 94%, 100%, 98% and 100% respectively. With the use of ultrasound: there was a sensitivity of: 90% hip, 87% knee, 93% OM and 100% spine plates and screws. Specificity: 94%, 100%, 92% and 80% respectively. 13 patients received preoperative antibiotic treatment. With the use of ultrasound 10 were detected, with cultures 7. Both techniques were compared using the Fisher test. Ultrasound was more sensitive when a global prosthetic culture was done (p< 0.001) and in knee prosthesis (p< 0.04). No differences were seen with other implants.

Discussion and Conclusions: Culture after ultrasound had been applied was seen to be more sensitive than culture of conventional tissue. The use of ultrasound was more effective in patients that received prior treatment with antibiotics.