Predictors of clinical response to intraarticular Hylan injections -- a prospective study using synovial fluid measures, clinical outcomes, and magnetic resonance imaging.
OBJECTIVE
To evaluate synovial fluid (SF) and clinical and imaging predictors of clinical response in patients receiving intraarticular Hylan GF-20 injections.


METHODS
Thirty-two patients with mild to moderate osteoarthritis (OA) of the knee [OsteoArthritis Research Society International (OARSI) grades I-II] were followed over 6 months. SF and clinical and radiographic measures were assessed. Patella and tibial cartilage volume and cartilage defect scores were measured at baseline and 6 months using magnetic resonance imaging (MRI). The primary outcome measure was the relationship between SF measures and clinical response as defined by the OARSI-Outcome Measures in Rheumatology Clinical Trials responder criteria for OA ("High improvement" >or= 50% improvement in pain or function; absolute change >or= 20 NU on Western Ontario and McMaster University Osteoarthritis Index questionnaire). Secondary outcomes included MRI outcomes (change in cartilage volume and cartilage defect scores).


RESULTS
Fifteen patients achieved "High improvement." High baseline SF hyaluronic acid (HA) concentration was a statistically significant predictor of clinical response with odds ratio (OR) 6.04 (p < 0.02). HA concentration was divided into tertiles and fitted to a univariate regression model against clinical response. A baseline HA concentration value of > 2 mg/ml provided the greatest tradeoff between sensitivity and specificity with values of 60% and 77%, respectively, a likelihood ratio of 2.55, and OR of 4.88. Baseline clinical and radiological measures did not predict clinical response in this cohort with mild to moderate OA. Nineteen subjects had MRI at both timepoints. No change was noted in cartilage volumes or cartilage defect scores over 6 months. There was no association between baseline HA concentration and baseline cartilage volume.


CONCLUSIONS
Baseline SF HA concentration predicts clinical response in patients receiving intraarticular Hylan. This has implications for the selection of patients who are likely to respond to this therapy.
Anandacoomarasamy
Ananthila
A
Institute of Bone and Joint Research, Royal North Shore Hospital, University of Sydney, Sydney, Australia.
Bagga
Hanish
H
Ding
Changhai
C
Burkhardt
Daniel
D
Sambrook
Philip N
PN
March
Lyn M
LM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001672:Biocompatible Materials / Q000008:administration & dosage*; D002358:Cartilage, Articular / Q000187:drug effects / Q000473:pathology; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000378:metabolism; D007270:Injections, Intra-Articular; D007719:Knee Joint / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000175:diagnosis / Q000188:drug therapy* / Q000378:metabolism; D010146:Pain / Q000188:drug therapy / Q000209:etiology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013582:Synovial Fluid / Q000378:metabolism*; D016896:Treatment Outcome
D001672:Biocompatible Materials; C049816:hylan; D006820:Hyaluronic Acid