Evaluation of samarium-153 for synovectomy in an osteochondral fragment-induced model of synovitis in horses.
OBJECTIVE
To determine the effects of intraarticular administration of Samarium-153 (153Sm) bound to hydroxyapatite microspheres (153SmM) on an osteochondral chip-induced synovitis.


METHODS
Sixty days after implantation of autogenous osteochondral fragments in the middle carpal and metacarpophalangeal joints, 153SmM was administered into 1 joint of each type. The contralateral joints were used as untreated controls.


METHODS
Fifteen horses without preexisting joint disease were randomly divided into 2 groups (7 in the carpal group, 8 in the metacarpophalangeal group).


METHODS
Horses had osteochondral fragments that were harvested from the lateral ridge of the trochlea of the talus and implanted bilaterally into a middle carpal joint and a metacarpophalangeal joint; the opposite joint type served as a control. Sixty days later, 10 to 15 mCi of 153SmM (20 to 50 microm diam) was injected into the fragment-implanted joints. Three horses were treated with nonradioactive hydroxyapatite fragments. Horses were examined clinically until they were killed 14 or 30 days later. Control and treated joints were examined grossly and microscopically to determine the effects of 153SmM on synovial membrane and cartilage.


RESULTS
Intraarticular 153SmM caused a transient flare with lameness, effusion, and edema for 48 to 72 hours. Implanted osteochondral chips induced a synovitis characterized by variable degrees of joint damage and synovial infiltrate. Use of 153SmM resulted in synovectomy of variable depth and extent.


CONCLUSIONS
Intraarticular 153SmM may be a useful method for synovectomy of inflamed synovial membrane.


CONCLUSIONS
With further testing, radioactive pharmaceuticals might become useful clinical treatments for persistent synovitis not responsive to conventional techniques.
Yarbrough
T B
TB
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis 95616, USA.
Lee
M R
MR
Hornof
W J
WJ
Schumacher
H R
HR
O'Brien
T R
TR
D000704:Analysis of Variance; D000818:Animals; D001672:Biocompatible Materials / Q000627:therapeutic use; D004195:Disease Models, Animal; D017886:Durapatite / Q000627:therapeutic use; D005260:Female; D005552:Forelimb / Q000601:surgery*; D006734:Horse Diseases / Q000188:drug therapy / Q000473:pathology / Q000601:surgery*; D006736:Horses; D007270:Injections, Intra-Articular / Q000662:veterinary; D008297:Male; D008863:Microspheres; D011868:Radioisotopes / Q000008:administration & dosage / Q000627:therapeutic use*; D011897:Random Allocation; D012493:Samarium / Q000008:administration & dosage / Q000627:therapeutic use*; D013585:Synovitis / Q000188:drug therapy / Q000601:surgery / Q000662:veterinary*
D001672:Biocompatible Materials; D011868:Radioisotopes; D012493:Samarium; D017886:Durapatite