Interrater variability in manual palpation of the medial femorotibial joint of Warmbloods and American Quarter Horses based on experience level

Summary Background Manual palpation of the equine medial femorotibial joint (MFT) is commonly performed during lameness evaluation. Previous studies have shown poor inter‐observer agreement between experienced clinicians and between stifle effusion palpation and ultrasonography. No study has been performed that has evaluated palpation agreement of the MFT based on low to high experience levels nor comparing two different breeds. Objectives To compare inter‐ and intra‐observer agreement between palpation and ultrasound in assessing effusion and joint capsule thickening of the MFT in two breeds. Study design Observational cross‐sectional. Methods Sixteen Quarter Horse and 16 Warmblood MFT were manually palpated for effusion and joint capsule thickening by three faculty members, three house officers and three fourth‐year veterinary students. Ultrasound of the MFT was performed and images were reviewed by a boarded radiologist. Stifle effusion and joint capsule thickening were graded on manual palpation and ultrasound images using 0–5 and binary scales. Interrater reliability was performed with the intraclass correlation coefficient for agreement by means of a 2‐way model. Spearman rank correlation was used to examine associations between palpation scores for each observer and ultrasound scores. Significance was set at p < 0.05. Results Interrater reliability for palpation of MFT effusion and joint capsule thickening was poor between all observers, regardless of experience level. No significant correlation was identified between palpation and ultrasound scores for any observer or between breeds. Main limitations Only two breeds were compared. Participants were chosen based on availability and may not accurately represent all experience levels. Conclusions Palpation of the MFT was highly variable, regardless of experience. Compared to ultrasound, manual palpation had no significant correlation, indicating low accuracy. These results were consistent across all experience levels and breeds, suggesting that palpation alone should not be relied upon to quantify effusion or joint capsule thickening in the MFT.