Double blind glucocorticoid controlled trial of samarium-153 particulate hydroxyapatite radiation synovectomy for chronic knee synovitis.
BACKGROUND
Samarium-153 particulate hydroxyapatite (Sm-153 PHYP) is a relatively new radiation synovectomy agent developed for the treatment of chronic synovitis. Although it has been shown that the levels of unwanted extra-articular radiation are lower after intra-articular injection of Sm-153 PHYP than yttrium-90 colloid, its clinical efficacy has not been rigorously studied.


OBJECTIVE
To establish whether Sm-153 PHYP radiation synovectomy results in a clinically useful benefit sustained at one year.


METHODS
In a randomised double blind study, patients received either intra-articular 40 mg triamcinolone hexacetonide alone or 40 mg triamcinolone hexacetonide combined with Sm-153 PHYP in an outpatient clinic.


RESULTS
Sixty patients (28 male, 32 female), median age 51 (18-75) with chronic knee synovitis were studied. Diagnoses included: rheumatoid arthritis (n=29); psoriatic arthritis (n=9); ankylosing spondylitis (n=3); reactive arthritis (n=2); undifferentiated seronegative oligoarthritis (n=13) and miscellaneous inflammatory conditions (n=4). More patients who received Sm-153 PHYP/triamcinolone hexacetonide sustained clinical benefit a year after treatment compared with patients who received corticosteroid alone (12 of 31 (39%) v 6 of 29 (21%), a difference of 18% more patients (95% CI -5% to 41%)) though the difference was not significant (chi(2)=2.31, 0.2>p>0.1, n=60). Despite the variation in injected activity (median 563 MBq, range 218-840 MBq), there was no obvious relation between low levels of injected activity (<555 MBq) and relapse within 12 months of treatment (chi(2) =2.61, 0.2>p>0.1, n=31).


CONCLUSIONS
There was no clear beneficial clinical effect of combined Sm-153 PHYP/triamcinolone hexacetonide injection over triamcinolone hexacetonide alone a year after treatment for chronic knee synovitis.
O'Duffy
E K
EK
Institute of Nuclear Medicine, University College London.
Clunie
G P
GP
Lui
D
D
Edwards
J C
JC
Ell
P J
PJ
D000287:Administration, Topical; D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D002908:Chronic Disease; D003131:Combined Modality Therapy; D004311:Double-Blind Method; D005260:Female; D005938:Glucocorticoids; D006801:Humans; D006882:Hydroxyapatites / Q000627:therapeutic use*; D007719:Knee Joint; D008297:Male; D008875:Middle Aged; D011868:Radioisotopes / Q000627:therapeutic use*; D012493:Samarium / Q000627:therapeutic use*; D013585:Synovitis / Q000532:radiotherapy*; D014222:Triamcinolone Acetonide / Q000031:analogs & derivatives / Q000627:therapeutic use
D000893:Anti-Inflammatory Agents; D005938:Glucocorticoids; D006882:Hydroxyapatites; D011868:Radioisotopes; C091049:samarium hydroxyapatite; D012493:Samarium; D014222:Triamcinolone Acetonide; C005900:triamcinolone hexacetonide