Acetabular Coverage Area Occupied by the Femoral Head as an Indicator of Hip Congruency

Abstract

Accurate radiographic screening evaluation is essential in the genetic control of canine HD, however, the qualitative assessment of hip congruency introduces some subjectivity, leading to excessive variability in scoring. The main objective of this work was to validate a method-Hip Congruency Index (HCI)-capable of objectively measuring the relationship between the acetabulum and the femoral head and associating it with the level of congruency proposed by the Fédération Cynologique Internationale (FCI), with the aim of incorporating it into a computer vision model that classifies HD autonomously. A total of 200 dogs (400 hips) were randomly selected for the study. All radiographs were scored in five categories by an experienced examiner according to FCI criteria. Two examiners performed HCI measurements on 25 hip radiographs to study intra- and inter-examiner reliability and agreement. Additionally, each examiner measured HCI on their half of the study sample (100 dogs), and the results were compared between FCI categories. The paired t-test and the intraclass correlation coefficient (ICC) showed no evidence of a systematic bias, and there was excellent reliability between the measurements of the two examiners and examiners’ sessions. Hips that were assigned an FCI grade of A (n = 120), B (n = 157), C (n = 68), D (n = 38) and E (n = 17) had a mean HCI of 0.739 ± 0.044, 0.666 ± 0.052, 0.605 ± 0.055, 0.494 ± 0.070 and 0.374 ± 0.122, respectively (ANOVA, p < 0.01). Therefore, these results show that HCI is a parameter capable of estimating hip congruency and has the potential to enrich conventional HD scoring criteria if incorporated into an artificial intelligence algorithm competent in diagnosing HD.

The Role of Femoral Head Size and Femoral Head Coverage in Dogs with and without Hip Dysplasia

“…There is also a strong positive correlation of relative body length with a higher prevalence of CHD in certain dog breeds [ 30 ]. In a recent study, investigators [ 31 ] developed and validated a new index (Hip Congruency Index; HCI) to assess hip joint congruity and to incorporate this parameter into an artificial intelligence algorithm. The CFH was related to the acetabular area, and the resulting index decreased gradually with statistically significant differences between all FCI categories.…”

Femoral Neck Thickness Index as an Indicator of Proximal Femur Bone Modeling

“…We use the FNTi to get around the difficulty that exists in veterinary medicine to use absolute measures in anatomic measurements due to the different sizes of dogs. The relationship between measurements and the size of the femoral head is a strategy that has been successfully used previously for other purposes, such as the hip distraction index (mainly in young animals without severe bone changes) [ 1 , 6 ] and the hip congruency index [ 11 ]. In a previous study, the femoral neck width was related with the femoral neck length to create a widening index [ 31 ].…”

“…In a previous study, the femoral neck width was related with the femoral neck length to create a widening index [ 31 ]. However, this methodology was not followed in this work because we think that the relationship between the length of the femoral neck and the size of the breed is much less studied and used than the diameter of the femoral head [ 6 , 11 ]. As such, there may be greater variability in the length of the femoral neck between breeds of similar sizes, which makes this parameter a less effective ratio measure.…”

“…These include: variability between radiologists’ assessments, which is due to different levels of expertise among radiologists; screening systems that are not yet sufficiently standardized and strict, allowing for some subjectivity; the late appearance of unequivocal pathognomonic radiographic signs, at an age stage in which sometimes the dog has already entered the breeding pool; and the absence of evaluation of potential early hip joint changes in this view [ 8 , 9 , 10 ]. Therefore, the current incidence of CHD highlights the need to introduce new parameters to improve diagnosis, such as the hip congruency index, which has the potential to confer greater objectivity to the assessment of hip congruency, consequently benefiting overall diagnostic and scoring accuracy [ 11 ].…”

Osteoarthritis, adipokines and the translational research potential in small animal patients

“…In addition, the abnormal load distribution due to hip joint laxity will cause malformation and remodeling of the hip. In dogs and cats, this typically leads to a shallow acetabulum, incongruity between acetabulum and femoral head and finally progressive OA ( 76 ). Hip dysplasia typically affects young actively growing animals.…”