Audiometric threshold shifts after total knee arthroplasty by using gentamicin-loaded bone cement

Prior research has shown that gentamicin is a commonly used antibiotic in orthopedic procedures due to its broad-spectrum activity. However, the potential for ototoxic effects remains a concern in clinical settings. It was already known that gentamicin can affect auditory function when administered systemically. No prior work had resolved whether local delivery via bone cement reduces this risk. This gap motivated the need to evaluate whether gentamicin-loaded bone cement could lead to temporary or permanent hearing changes. The concern is especially relevant in procedures like total knee arthroplasty where local antibiotic use is routine. Understanding the auditory impact of gentamicin in this context is essential for patient safety. This study aimed to address the uncertainty by comparing outcomes between patients receiving gentamicin-loaded cement and those receiving standard cement.

The aim of the study was to assess whether gentamicin-loaded bone cement leads to audiometric threshold shifts in patients undergoing primary total knee arthroplasty. The study compared patients receiving gentamicin-loaded cement with those receiving standard cement. The motivation was to determine if local antibiotic delivery could reduce the risk of ototoxicity. The researchers focused on detecting any changes in hearing thresholds post-surgery. The study design allowed for a direct comparison between the two groups. The goal was to evaluate the safety of gentamicin in this context. The researchers wanted to know if the observed shifts were temporary or permanent. This investigation is important for orthopedic and audiological practice.

The study was a prospective case-control design involving 40 patients in the gentamicin group and 29 in the control group. All patients underwent primary total knee arthroplasty. The gentamicin group received bone cement loaded with gentamicin. The control group received standard bone cement without gentamicin. Pure-tone audiometric evaluations were conducted preoperatively and on the third postoperative day. Weekly audiometric follow-ups were performed for patients showing threshold shifts. Ototoxicity was defined based on the observed audiometric changes. The study focused on detecting temporary or permanent hearing alterations.

Ototoxicity was diagnosed in 8 of 40 patients (20%) in the gentamicin group. No cases of ototoxicity were observed in the control group. Audiometric threshold shifts were detected in the gentamicin group postoperatively. These shifts were not present in the control group. The observed changes were not permanent in the gentamicin group. Follow-up evaluations showed no lasting hearing effects. Patients with threshold shifts did not report hearing complaints. The study suggests that local gentamicin delivery may lead to temporary auditory changes.

The authors propose that audiometric threshold shifts can occur in patients receiving gentamicin-loaded bone cement. However, these shifts were not permanent in the observed follow-up period. The study suggests that local gentamicin use may lead to temporary auditory effects. No permanent hearing loss was observed in the gentamicin group. The findings highlight the need for audiometric monitoring in such cases. The absence of clinical complaints supports the idea that the changes are not functionally significant. The study does not suggest that gentamicin-loaded cement is unsafe. The results emphasize the importance of close follow-up for early detection.