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

Abstract

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. This was a cadaveric radiographic anatomical study. that involved 20 short-haired domestic adult cats. 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. 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. 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.