33rd Annual Scientific Meeting proceedings

Introduction
Arthroscopic guided injection of corticosteroids into the fibrous lining of subchondral bone cystsinvolving the medial femoral condyle (MFC) is a well-recognised procedure. The technique is perceived as effective with a rapid return to athletic function. Outcome following treatment in a UK TB racehorse population has not been reported. 

Materials and methods
Medical records were searched for thoroughbred horses intended for racing with MFC cysts treated by arthroscopic-guided injection between 2011-2021. Follow up was obtained via medical records, performance data was obtained from www.racingpost.co.uk. Horses with <1 year follow-up and those undergoing concurrent treatments were excluded.  

Results
Criteria was met by 46 horses undergoing a total of 51 surgical procedures. Data included 15 yearlings, 28 x2 year olds 7 x 3 year olds and 1 horses >4 yrs.  27 cases were female, 25 male.  Forty-five cases presented with lameness. Cysts were unilateral in 34 cases (27RH ,7 LH) and bilateral in 17 cases. Mean grade of cyst treated was 4 (Sanschi et al, 2014). Treatment entailed either 10-20mg Triamcinolone Acetate (43 cases) or 80-120mg Methylprednisolone (8 cases) per site. Seven horses had raced prior to surgery, 32 horses had a race start following surgery (62%) at a mean of 303 days post-surgery (24-861), 234 days when only horses >1 at the time of surgery were included.

Conclusions
Arthroscopic medication of MFC cysts in UK TB horses allows the majority of horses to return to racing.  Median time to racing was longer than that reported for soundness following transcortical screw placement.