Validation of two simple, objective tools for the assessment of synovial swelling in the equine fetlock region

Abstract

Simple objective assessment tools are essential to monitor the efficacy of therapeutic interventions used in clinical settings. The purpose of present study was to investigate different ways of assessing synovial swelling of the equine fetlock region: tape measure and slide calliper, and to examine the method’s inter- and intra-examiner reliability. The hypotheses were that inter-examiner reliability would be fair and intra-examiner reliability strong. Measurements were performed on both hind limbs, on 16 horses. Palpation was done once for each limb, over the plantar pouch of the fetlock joint and the plantar digital flexor tendon sheath (PDFTS). Tape measure and slide calliper registrations were made, in triplicate by two independent assessors blinded to the measurements, horizontally over the fetlock joint and PDFTS areas, respectively. Intra-class correlation was used to measure inter- and intra-examiner reliability. The inter-examiner reliability was fair for the tape measurement of the plantar pouch of the fetlock joint, and almost perfect for the PDFTS. It was moderate for the slide calliper assessment of the PDFTS and almost perfect for the plantar pouch. The intra-examiner reliability was almost perfect for tape measure and slide calliper assessment, for the plantar pouch and PDFTS, respectively. Our results support our hypothesis and indicate that tape measure and slide calliper measurement of plantar pouch of the fetlock joint and PDFTS can be reliably performed by the same therapist. Slide calliper and circumference tape measures are promising objective techniques for assessing synovial swelling of the equine fetlock region.