A feasibility of ultrasonographic assessment for femoral trochlear depth and articular cartilage thickness in canine cadavers

Abstract

Trochleoplasty or trochlear groove deepening is one of surgical correction techniques for patellar luxation (PL) that
caused cartilage alterations of the distal femur and this technique may not be always necessary. To evaluate trochlear
groove for PL correction preoperative planning, several diagnostic image techniques have been applied. In this study,
ultrasonography (USG) was introduced in the trochlear evaluation as pre-operative planning because it’s user-friendly
and radiationless. USG imaging of 22 distal femurs from small breed of canine cadavers were evaluated for trochlear
groove depth (TGD) and trochlear cartilage thicknesses (CT) at medial condyle (MCCT), femoral groove (FGCT) and
lateral condyle (LCCT), and compared to those of other distal femoral evaluations such as conventional radiography
and/or anatomical appearance observed through stereomicroscope (STR). The results showed that TGD on radiograph
was significantly deeper than those on USG and STR (P = 0.0099 for USG and P = 0.0021 for STR) but TGD on USG and
STR was not significant difference (P > 0.9999). MCCT, FGCT and LCCT were evaluated and compared only between
USG and STR and the results showed that only FGCT between techniques were not significant difference (P = 0.0646).
At the condyles, MCCT and LCCT on USG were significantly thicker than those on STR (P = 0.006 for MCCT and P =
0.0004 for LCCT). In conclusion, USG was a reliable technique for TGD and FGCT evaluations. However, to evaluate
the MCCT and LCCT by USG, CT may be slightly exaggerating. This diagnostic imaging technique could be applied in
clinical practice and further evaluations of bone appearance between the normal and PL dogs should be done.