Assessment of coxofemoral joint laxity in juvenile boerboel dogs using mobile phone goniometry

Abstract

BACKGROUND Canine hip dysplasia (CHD) is closely associated with hip joint laxity (HJL), which is considered as one of the primary precursors to coxofemoral degenerative joint disease. However, the relationship between HJL and hip joint range of motion remains underexplored. OBJECTIVES This study aimed to investigate a correlation between hip joint angles (rotation and abduction) and the laxity index (LI) measured by the Vezzoni Modified Badertscher Distension Device technique (VMBDD) in juvenile boerboels. METHODS Hip joint angles were measured in 33 boerboels (aged 4-12 months) using mobile phone goniometer-based measurements by three independent examiners for abduction, internal, and external rotation. Stress view radiography with the VMBDD method assessed HJL, and LI's correlation with measured angles were examined. Inter-and-intra-operator variability of hip joint angles were also evaluated. RESULTS No significant correlation was found between abduction or internal rotation angles and laxity. However, external rotation demonstrated a weak correlation with laxity (r=0.207, p=0.095). Weight had a significant negative correlation with laxity (r=-0.265, p=0.031). Intra-operator variability ranged from 2.2 to 5.9, with the highest variability noted with internal rotation (4.0 to 5.9). Inter-operator variability ranged from 4.4 to 11.4, with the greatest variability observed in internal and external rotation (11.4 and 10.9, respectively). CONCLUSION Mobile phone goniometry appears unreliable for predicting joint laxity due to high inter- and intra-operator variability with poor repeatability.