Efficacy of needle and endoscopic lavage on the recuperation of microspheres from the adult equine metacarpo−/metatarsophalangeal joint and digital flexor tendon sheath

Abstract

Objectives: To measure microsphere recovery following needle-through-and-through lavage (NTAT) of the metacarpo−/metatarsophalangeal joint (fetlock) and digital flexor tendon sheath (DFTS) compared to endoscopic lavage (EL).

Study design: Ex vivo experimental study.

Animals: Adult equine cadavers immediately following euthanasia (n = 10).

Methods: Colored 15 μm microspheres (2 million) were injected into fetlock joints and DFTS. Synovial structures were assigned to NTAT or EL groups. Each lavage was performed using 5 L of 0.9% NaCl, sequentially collecting egress fluid for microsphere quantification. Recovery was compared using a full-factorial general linear model.

Results: There was a significant effect of the liter of egress fluid and microsphere recovery in both fetlocks (p <.01) and DFTS (p <.01), with most microspheres recovered in the first 2 L (79%–83%) for both techniques. More microspheres were recovered in the first liter using NTAT than EL (p <.01) in both fetlocks (659 883 ± 20 820 vs. 567 601 ± 24 452) and DFTS (644 341 ± 17 460 vs. 550 637 ± 38 022). No difference in total recovered microspheres was observed between NTAT lavage of fetlock (981 600 ± 46 839) and DFTS (957 419 ± 45 729) across 5 L (p =.88).

Conclusion: Needle-through-and-through lavage was more effective than EL at recovering microspheres in the first liter from cadaveric equine fetlock joints and DFTS. Both techniques demonstrated comparable efficacy between fetlock and DFTS in microsphere recovery following increased lavage volumes.

Clinical significance: Needle-through-and-through lavage (NTAT) is a viable alternative for suspected synovial contamination when EL is delayed or not feasible. This study does not evaluate NTAT's efficacy for treating established sepsis or removing pannus/foreign bodies.