[¹⁸F]NaF PET/CT to assess bone healing capacity in orthopaedic trauma surgery: a feasibility study

Evaluation of bone healing potential in cases of delayed union or non-union remains a challenge. This study evaluated the use of [¹⁸F]NaF PET/CT to assess bone healing and its role in guiding clinical decision-making in orthopaedic trauma surgery.

From June 2019 to December 2024, a prospective study was conducted in a level 1 trauma center. The study included 18 patients (20 fractures: 15 non-unions, 5 bone defects) all showing impaired bone healing after initial surgical fracture treatment, who were eligible for revision surgery. Dynamic (first 10 min post-tracer injection) and static (1-hour post-injection) [¹⁸F]NaF PET/CT scans were performed to assess bone healing capacity through qualitative and quantitative analysis. The relationship between scan results and treatment outcome was evaluated.

Increased [¹⁸F]NaF uptake, suggestive for bone healing capacity, was observed in all fractures (20/20). Based on the positive [¹⁸F]NaF PET/CT results, watchful waiting was recommended for all fractures, with two patients preferring surgery. After prolonged watchful waiting, 72% (13/18) showed bone healing progression. Notably, atrophic fractures displayed biological activity, and non-unions demonstrated sustained metabolic activity even beyond 12 months. Most fractures requiring revision surgery (80%, 4/5) needed additional stabilization. Ultimately, [¹⁸F]NaF PET/CT imaging helped to avoid revision surgery in 65% of all fractures (13/20). Uptake pattern analysis suggest that whole-bone uptake could potentially indicate surgical need (χ² = 5.62, p = 0.018). Quantitative assessment provided no additional information.

[¹⁸F]NaF PET/CT imaging provides valuable insights into bone healing potential, especially in non-unions, helping guide clinical decisions and reducing unnecessary surgeries. This study challenges traditional non-union definitions by highlighting the biological activity of both atrophic and hypertrophic fractures.