Knee radiosynovectomy with ¹⁵³Sm-hydroxyapatite compared to ⁹⁰Y-hydroxyapatite: initial results of a prospective...

Radiosynovectomy (RS) with ⁹⁰Y-hydroxyapatite (⁹⁰Y-HyA) aims to control knee hemarthrosis in hemophiliac patients to prevent secondary arthropathy. However, knee RS using ¹⁵³Sm-hydroxyapatite (¹⁵³Sm-HyA) is considered less suitable due to the lower average soft tissue range and energy of ¹⁵³Sm for large joints, such as the knees.

The objective of this investigation was to assess the efficacy and safety of knee RS with ¹⁵³Sm-HyA, compared to ⁹⁰Y-HyA.

Forty patients were prospectively assigned to undergo knee RS with ¹⁵³Sm-HyA (n = 19) or with ⁹⁰Y-HyA (n = 21). The frequency of hemarthrosis episodes before and after treatment were compared.

After six months of knee RS, ¹⁵³Sm-HyA and ⁹⁰Y-HyA promoted a similar reduction of hemarthrosis episodes (50% and 66.7%, respectively). However, after 12 months of knee RS, the reduction of hemarthrosis episodes was significantly (p = 0.037) higher using ¹⁵³Sm-HyA (87.5%) compared to ⁹⁰Y-HyA (50.0%). This discrepancy was more pronounced (p = 0.002) for ¹⁵³Sm-HyA compared to ⁹⁰Y-HyA in adults/adolescents.

Knee radiosynovectomy with ¹⁵³Sm-HyA is safe, reduces hemarthrosis episodes after 12 months of treatments, especially in adults/adolescents and even with grades III/IV arthropathy, similar to ⁹⁰Y-HyA. ⁹⁰Y-HyA seems to promote better hemarthrosis control in small children.