RESUMEN
OBJECTIVES: Platelet preparations have become a treatment for soft tissue injuries in horses. This study evaluated a novel filter-based system to concentrate platelets and assesses its value in the treatment of suspensory ligament branch desmitis. METHODS: Filtered platelet concentrate was prepared from 55 ml of venous blood obtained from 21 normal horses. Platelets and white blood cells in whole blood and filtered platelet concentrate were measured, as was platelet activating factor (PAF)-induced platelet-derived growth factor-BB (PDGF-BB) release. Eleven horses with 18 focal acute suspensory ligament branch injuries were treated intra-lesionally with autologous filtered platelet concentrate and evaluated clinically and ultrasonographically for one to three years. RESULTS: The increase in concentration of platelets in the filtered concentrate in comparison with whole blood (6.9 ± 1.9-fold) was significantly greater than the increase in white blood cells (3.8 ± 0.8-fold) (p <0.0001). There was no effect of sex or breed on platelet concentration. Platelets were responsive to PAF with >100-fold higher levels of PDGF release over basal levels. All hypoechoic lesions re-evaluated within three months had resolved. Five of the 11 horses returned to their previous level of work, one was exercising at a lower level, three were retired, one died for unrelated reasons, and one was still convalescing. CLINICAL SIGNIFICANCE: Filtered platelet concentrate was easily and reliably prepared and injected into suspensory ligament branch injuries without short-term complications. This treatment was associated with rapid resolution of ultrasonographic lesions and lameness. Filtered platelet concentrate represents a convenient alternative for the treatment of suspensory ligament branch injuries.