¹Center for Musculoskeletal Surgery, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Deutschland
²Istituto Ortopedico Rizzoli, Bologna – Università degli Studi “Alma Mater Studiorum” di Bologna, Bologna, Italien
³Department of Diagnostic and Interventional Radiology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Deutschland
⁴Institute of Biometry and Clinical Epidemiology, Charité – Universitätsmedizin Berlin, Berlin, Deutschland
⁵Julius Wolff Institute, Berlin Institute of Health at Charité – Universitätsmedizin Berlin, Berlin, Deutschland
⁶Berlin Institute of Health Center for Regenerative Therapies, Berlin Institute of Health at Charité – Universitätsmedizin Berlin, Berlin, Deutschland

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Objectives and questions: More than 3.5 million Total Knee Replacements (TKA) are performed annually worldwide, yet approximately 20% of patients continue to experience persistent pain after surgery, with 10% of this pain remaining unexplained. Diagnosing the source of pain in TKA is complex and therapeutic options for unexplained pain are very limited, leading to significant consequences on patients quality of life. Purpose of this study is to evaluate the safety and efficacy of hypervascular Genicular Arteries Embolization (GAE) in reducing chronic pain after TKA. Moreover, this study aims to present a defined diagnostic-therapeutic Rule-out Algorithm for painful TKA in order to select optimal candidates for genicular arterial embolization.

Material and methods: This prospective, single-center pilot study included 28 patients with persistent pain after TKA. All patients were selected after completing a diagnostic rule-out algorithm for other potential causes of pain, thus being classified as having unexplained painful prostheses. Embolization was performed using temporary particles targeting hypervascular regions identified via angiography. Outcomes were assessed at baseline, six weeks, three, six, and twelve months post-procedure using the Knee Injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Patient-Reported Outcomes Measurement Information System (PROMIS). Adverse events were recorded throughout follow-up.

Results: An average of 2.2 ± 0.9 abnormal hyperemic genicular arteries were embolized, with a median volume of 2.6 mL of embolic material used. KOOS Pain scores improved from 39 ± 13 at baseline to 56 ± 25 at six months (P < .05). PROMIS Pain Interference scores decreased from 65 ± 18 to 41 ± 10 at six months (P < .05). KOOS Quality of Life scores improved in 79% of patients at 12 months. Transient skin discoloration occurred in 5 patients (18%).

Discussion and conclusions: Preliminary findings suggest that GAE is a safe and potentially effective treatment for managing chronic unexplained pain after TKA. Moreover, the study highlights the integration of GAE into a diagnostic-therapeutic algorithm for post-TKA pain. Further research with larger, randomized cohorts is recommended to confirm these findings.

Figure 1 [Fig. 1]