Re-evaluating the need for hospitalization following synovectomy using Yttrium-90 silicate

Area of Science:

• Nuclear medicine
• Radiopharmacology
• Rheumatology

Background:

• Yttrium-90 (Y-90) synovectomy is a treatment for inflammatory arthritis (IA) and osteoarthritis (OA) of the knee.
• Understanding Y-90 retention and extra-articular uptake is crucial for optimizing treatment outcomes.

Purpose of the Study:

• To investigate factors influencing Yttrium-90 (Y-90) retained knee activity (RKA) and extra-articular uptake in patients with knee arthritis.
• To compare Y-90 distribution in inflammatory arthritis (IA) versus osteoarthritis (OA) and assess the impact of injection laterality and immobilization.

Main Methods:

• Retrospective analysis of 51 patients undergoing Yttrium-90 (Y-90) synovectomy for knee IA and OA.
• Assessment of retained knee activity (RKA) and extra-articular uptake (lymph nodes, liver) using scintigraphy.
• Correlation with joint inflammation markers (radionuclide blood pool scan, SF white cell count) and treatment parameters (immobilization, intra-articular steroids).

Main Results:

• Decreased RKA and increased extra-articular activity were more common in IA than OA, and after bilateral knee injections.
• Joint inflammation, assessed by radionuclide blood pool scan, correlated with decreased RKA and increased lymph node activity.
• Strict hospital immobilization improved RKA in IA but not in OA; intra-articular steroids had no significant effect.

Conclusions:

• Yttrium-90 (Y-90) synovectomy in OA demonstrates good RKA and low extra-articular uptake.
• Strict immobilization post-Y-90 synovectomy is recommended, especially for IA patients or those with high joint blood flow, to enhance RKA.