Aim: This study aimed to assess the outcome of yttrium-90 radiation synovectomy (RS) in patients with knee activated osteoarthritis in a decade follow-up period.
Methods: We prospectively evaluated 52 patients, aged 64 years (42–86 years) of age, with osteoarthritic (Kellgreen–Lawrence grades I–III) knee pain resistant to conventional therapy referred for intraarticular yttrium-90 treatment in 2011, due to synovial inflammation, as demonstrated by early-phase bone scintigraphy. All patients were offered a long-term follow-up to almost a decade after initial treatment at 6, 12, and 60 months and then every year up to 120 months (only 12/52 patients finally managed to fully participate). Treatment outcome was evaluated by assessing the variation of a composite index (CCi) calculated in terms of a patient subjective visual analogue scale (VAS) reporting knee pain in combination with a scoring system of objective clinical and functional parameters at rest and under load (joint edema/hyperthermia, pain in load, flexion, ability to walk, intra-articular therapies after RSO, and knee surgery), ranging from 0 (no change–worsening) to 35 (excellent response).
Results: After first RSO, 21 patients underwent no other intra-articular treatment, with a range of 1 to 6 knee punctures for the rest of patients. The overall response rate for all treated joints was 65% at 12 months and 54% at 120 months (p = not significant). The mean improvement rate for early stage (Kellgreen–Lawrence grade I/II) treated joints was higher than the one achieved by all patients in total.
Conclusion: Yttrium-90 radiation synovectomy exerts a beneficial therapeutic effect in patients suffering of knee synovial inflammation due to osteoarthritis. Long-term results are excellent/good in many patients, almost 10 years after initial therapy, with better results succeeded in the cases of radiological minimal changes (early Kellgreen–Lawrence stage).
