A new approach in the treatment of ultrasound-guided synovial hypertrophy.

Background/aim: Knee osteoarthritis (OA) causes pain and limited movement, negatively impacting daily life in older adults. Hypertrophy and changes in the synovial tissue significantly contribute to the pain. While intraarticular injections are common in OA treatment, specific therapies for hypertrophic tissue are rarely mentioned. This study aimed to evaluate the long-term outcomes of local anesthetic and steroid injections in the knee's intraarticular space and hypertrophic synovial tissue. Materials and methods: Our retrospective study included patients with grade 3 or 4 knee OA diagnosed with ultrasound-guided suprapatellar effusion and synovial hypertrophy. Pain was assessed using a numerical rating pain scale (NRS) and functional capacity was evaluated with the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index. Effusion was first drained from the suprapatellar region using a 22-gauge spinal needle under ultrasound guidance, followed by lavage with 40 mL of 0.9% NaCl solution. A mixture of 10 mL (2 mL triamcinolone hexacetonide, 7 mL of prilocaine, and 1 mL of 0.9% NaCl) was injected intraarticularly, and 6 mL was injected into the hypertrophic synovial tissue. Patients were followed before the injection and at 1, 3, 6, 9, and 12 months after the injection. Results: Analysis of the WOMAC scores and NRS values at 1, 3, 6, 9, and 12 months after the injection revealed statistically significant reductions (p < 0.05). No statistical difference was found between the duration of complaints and WOMAC scores or NRS values (p > 0.05). Ultrasound evaluation indicated regression of the synovial hypertrophy tissue. Conclusion: This injection method, practiced in the treatment of synovial hypertrophy as one of the causes of pain in knee OA, reduced pain and significantly increased functional capacity.