Diagnosis of periprosthetic loosening of total hip and knee arthroplasty using ⁶⁸Gallium-Zoledronate PET/CT

Purpose: Periprosthetic loosening is a major complication after total hip and knee arthroplasty. Early and accurate diagnosis is essential to choose the right therapeutic path and to avoid further complications. The aim of the study was to evaluate the diagnostic performance of ⁶⁸Gallium-Zoledronate ([⁶⁸Ga]Ga-DOTA^Zol) PET/CT in detecting periprosthetic loosening in total hip (THA) and total knee arthroplasty (TKA).

Methods: This retrospective study included 26 patients with painful prosthesis (THA n = 17; TKA n = 16) and clinical suspicion of periprosthetic loosening, but without a confirmed diagnosis. Patients underwent [⁶⁸Ga]Ga-DOTA^Zol PET/CT at least one year post-implantation. Diagnosis was confirmed through revision surgery or long-term clinical follow-up, with an observation period of at least 6 months. The analysis included both an assessment of the prosthesis as a unit and a separate evaluation of the individual components. Statistical analysis involved calculating sensitivity, specificity and accuracy using SPSS.

Results: Overall, a sensitivity of 77.8%, a specificity of 95.8% and an accuracy of 90.9% were found for detecting periprosthetic loosening, when considering the prosthesis as a unit. Individual component analyses showed a sensitivity of 71.4% and specificity of 96.2%.

Conclusion: The use of [⁶⁸Ga]Ga-DOTA^Zol PET/CT in periprosthetic loosening is a remarkable diagnostic tool and a promising approach. In comparison to established radionuclide tracers, ⁶⁸Gallium-Zoledronate offers notable advantages due to its availability via ⁶⁸Ge/⁶⁸Ga-generators, improving its potential for clinical application.