Effect of arthroscopic surgery and post-surgical triamcinolone acetonide administration on synovial fluid, serum, urine and kinetic biomarkers in an equine metacarpophalangeal osteochondral injury model

Abstract

Objective- The purpose of this pilot study was to investigate the effects of arthroscopic surgery and post-surgical administration of triamcinolone acetonide (TA) on biomarkers and lameness. Animals- Seven adult Quarter Horses had an osteochondral (OC) fragment arthroscopically created on the first phalanx of one metacarpophalangeal joint (MCPJ). Procedures- Lameness exams, force plate data, SF from both MCPJs, serum, and urine, were collected on weeks 0 (fragment creation), 16 (fragment removal), 17 (1 week post removal), 18 (1 week post injection, 2 weeks post removal) and 20 (3 weeks post injection, 4 weeks post removal). After week 17 fluid collection, horses were randomly divided into 2 intra-articular treatment groups: 10 mg TA (n=4) or 1 ml saline (n=3). Biomarkers of joint metabolism (BAP, CP II, C1,2C, C2C, CTX II, NO, and HMGB1) were evaluated in SF, serum, and/or urine using ELISAs. Repeated measures ANOVAs were used for analysis, significant at P < 0.05. Results- OC fragment creation resulted in collagen degradation as seen by SF increases of CTX II and C2C at week 16 from week 0 (P=0.048 and P<0.001). After TA administration, SF C2C concentrations increased, but CTX II concentrations decreased compared to saline controls (P<0.001). Bone production (SF BAP concentrations) in TA treated horses increased compared to saline controls at week 20 (P=0.028). All horses became more lame at week 17 according to trained observers (P=0.003) and force plate analysis (P=0.007), but by week 20, lameness had returned to pre-OC fragment removal (week 16) levels. There were no significant differences in SF, serum, urine and inflammatory biomarkers. Conclusions and Clinical Relevance- Arthroscopic surgery appears to have no effect on cartilage metabolism with little resultant SF inflammation. TA administration is not indicated after surgery for removal of OC fragments with superficial cartilage damage since collagen degradation increases compared to controls.