A comparison of two techniques for arthrocentesis of the equine metacarpophalangeal joint.

Because arthrocentesis of the metacarpophalangeal joint through the proximal palmar pouch may induce synovial haemorrhage, this study evaluated arthrocentesis through the lateral collateral sesamoidean ligament. The proximal palmar pouch and collateral sesamoidean ligament approaches were used in contralateral forelimbs to obtain paired initial synovial fluid samples from 16 horses 12 to 15 h before being killed. Synovial fluid samples also were collected from the same joints at necropsy and the subcutis, synovium and articular cartilage were evaluated. Metacarpophalangeal joint arthrocentesis through the collateral seamoidean ligament yielded fewer haemorrhagic synovial fluid samples with less subcutaneous and synovial inflammation, and also yielded 2 ml of synovial fluid more often than arthrocentesis through the proximal palmar pouch.