Good Inter- and Intra-Observer Reliability for Assessment of Radiographic Femoral and Tibial Frontal and Sagittal Planes Joints Angles in Normal Cats

Abstract

Objective The aim of this study was to evaluate the inter- and intra-observer reliability of plain digital radiographs for assessing normal feline femoral and tibial joint reference angles in the sagittal and frontal planes. Study Design This was a cadaveric radiographic anatomical study. that involved 20 short-haired domestic adult cats. Methods Sagittal and frontal plane tibial and femoral joint angles of 40 limbs were measured twice by three observers with different levels of experience. Inter- and intraobserver reliability was determined by the intra-class correlation coefficient (ICC). An ICC > 0.75 was considered high correlation, 0.74 > ICC > 0.60 good correlation, 0.59 > ICC > 0.4 fair correlation and an ICC < 0.40 poor correlation. Results Mean ± standard deviation angles were anatomic lateral proximal femoral angle (aLPFA) 110.6 ± 3.6; anatomic lateral distal femoral angle (aLDFA) 91.9 ± 2.1; mechanical lateral proximal femoral angle; mLPFA (mLPFA) 107.3 ± 3.6; mechanical lateral distal femoral angle (mLDFA) 95.5 ± 1.7; femoral neck anteversion (FNA) 121.9 ± 4.1; anatomical caudal proximal femoral angle (aCPFA) 156.1 ± 3.9; anatomical caudal distal femoral angle (aCDFA) 101.4 ± 1.4; mechanical medial proximal tibial angle (mMPTA) 93.5 ± 1.2; mechanical medial distal tibial angle (mMDTA) 100.5 ± 2.3; mechanical cranial proximal tibial angle (mCrPTA) 113.1 ± 3.2; tibial plateau angle (TPA) 23.1 ± 3.2; mechanical cranial proximal tibial angle (mCrDTA) 86.7 ± 3.1.The intra-observer ICC indicated high correlation for 70% or more of the measurements. The inter-observer agreement among observers was high. These results show that the radiographic method for measuring femoral and tibial joint angles was good or high, except for FNA and mCrDTA. Conclusions This study provides some radiographic anatomical and mechanical joint angles of the femurs and tibias of normal domestic short-haired cats. We found good reliability for both intra- and interobserver measurements.

Comparison of Hindlimb Conformation in Cats with and without Medial Patellar Luxation

“…Alternatively, it could be due to the different measurements obtained with radiography compared to CT. The mean aLDFA in our control group was 91.21 AE 1.69 which was comparable to 91.9 AE 2.1 previously reported in one study, 25 although lower than 93.8 AE 2.5 reported in another. 22 Although both previous studies measured proximal and distal tibial joint angles separately, they did not calculate overall TV.…”

“…Femoral and tibial joint angles have previously been reported in the normal cat but these were measured using radiography. 22 25 The mean AI in our control group was 125.85 ± 2.83 which is higher than the 121.9 ± 4.1 reported previously. 25 This could be due to the variation in breeds included in our study compared to just domestic shorthair being included in the previous study.…”

“…22 25 The mean AI in our control group was 125.85 ± 2.83 which is higher than the 121.9 ± 4.1 reported previously. 25 This could be due to the variation in breeds included in our study compared to just domestic shorthair being included in the previous study. Alternatively, it could be due to the different measurements obtained with radiography compared to CT.…”

“…22 Although both previous studies measured proximal and distal tibial joint angles separately, they did not calculate overall TV. 22,25 Femoral trochanteric angle, AA, DAA, PAA, TT and TTD were also not reported in either previous study. 22,25 This is likely due to the difficulty of measuring these values on conventional two-dimensional radiographs compared to a three-dimensional reconstruction obtained with CT.…”

“…A recent study investigated the normal anatomical angles of the femur and tibia radiographically in normal cats 25 however, this has not yet been established with CT and the effect of femoral and tibial conformation on patellar luxation has not previously been investigated in the cat. The primary aim of this study was to report and compare femoral and tibial conformation in a population of cats with and without medial patellar luxation.…”