(P 294) RISK FACTORS FOR RECURRENCE AND COMPLICATIONS OF CT-GUIDED RADIOFREQUENCY ABLATION FOR THE TREATMENT OF OSTEOID OSTEOMA: A MULTI-INSTITUTIONAL ANALYSIS.

Objective: Radiofrequency ablation (RFA) is the gold standard for treating symptomatic osteoid osteoma (OO), yet risk factors for recurrence and complications remain poorly understood. This study aimed to identify predictors of recurrence and local complications following RFA.

Methods: A retrospective cohort study of OO patients treated with RFA at two academic medical centers between 2010 and 2024 was conducted. Primary outcomes were recurrence—defined as the return of symptoms with radiological confirmation—and post-procedural complications. Secondary outcomes included clinical success (complete pain resolution) and technical success (procedure done according to protocol). Descriptive, univariable, multivariable, and survival analyses were performed, with a sub-analysis of anterior tibial lesions.

Results: A total of 272 patients were included. Median age was 20 years, and 69.5% of patients were male. The most common locations for OO were the femur (41.9%), tibia (26.5%), and foot (11.4%). The median tumor size was 7 mm. Recurrence occurred in 5.5% of cases, with spinal location as a risk factor (odds ratio [OR] = 6.22; p = 0.048). Complications were observed in 4% of patients, with increased risk in females (OR = 5.17; p = 0.01) and those with tibial lesions (OR = 13.23; p = 0.02). In tibial lesions, an anterior approach with the RFA probe was associated with a higher rate of wound infection (100% vs. 0%; p = 0.03).

Conclusion: RFA is a highly effective treatment for OO, with low rates of recurrence and complications. The identified risk factors underscore the need for tailored treatment plans. Furthermore, the anterior tibial approach should consistently incorporate a soft tissue buffer to minimize the risk of wound infection.