Geometric 3D analyses of the foot and ankle using weight-bearing and non weight-bearing cone-beam CT images: The new standard?

Abstract

We hypothesize that three-dimensional (3D) geometric analyses in weight bearing CT-images of the foot and ankle are more reproducible compared to two-dimensional (2D) analyses. Therefore, we compared 2D and 3D analyses on bones of weight-bearing and non weight-bearing cone-beam CT images of healthy volunteers. Methods: Twenty healthy volunteers (10 male, 10 female, mean age 37.5 years) underwent weight-bearing and non weight-bearing cone-beam CT imaging of both feet. Clinically relevant height and angle measurements were performed in 2D and 3D (for example: cuboid height, calcaneal pitch, talo-calcaneal angle, Meary's angle, intermetatarsal angle). Three-dimensional measurements were obtained using automated software. Intraobserver and inter-observer agreement were evaluated for all 2D measurements. Results: Overall intraclass correlation coefficients (ICC's) were higher than 0.750 for most 2D measurements, ranging from 0.352 to 0.995. Calcaneal pitch, angle between the first metatarsal (MT1) and proximal phalange 1, between the fifth metatarsal (MT5) and the calcaneus and heights of the sesamoid bones, navicular, cuboid and talus decreased during weight-bearing in both 2D and 3D results (p < 0.01). Meary's angle was not statistically different in 2D (p = 0.627) and 3D (p = 0.765). Higher coefficients of variation in 2D geometric analysis parameters (0.27 versus 0.16) indicate that 3D analyses are more precise compared to 2D (p < 0.01). Results of left and right feet are comparable for 2D and 3D analyses. Conclusion: Although 2D and 3D geometrical analyses are fundamentally different, automated 3D analyses are more reproducible and precise compared to 2D analyses. In addition, 3D evaluation better demonstrates differences in bone configurations between weight-bearing and non weight-bearing conditions, which may be of value to demonstrate pathology.

The effect of weight-bearing conditions on toe joint angles in healthy volunteers using weight-bearing CT

“…There was no signi cant difference found in our study of WB condition for most PIPJ and DIPJ angles of the healthy volunteers between nWB and WB conditions. This is different from most MTPJ angles and other joint angles in foot and ankle anatomy, such as the intermetatarsal angle between metatarsal (MT) 1 and MT2 and the angle between MT5 and the ground, which show differences between loading and non-loading [15]. We hypothesized that in individual cases the PIPJ and DIPJ angles would generally become smaller when the foot was loaded.…”

Three-dimensional analysis for quantification of knee joint space width with weight-bearing CT: comparison with non-weight-bearing CT and weight-bearing radiography

“…To the best of our knowledge, this is the first study performing 3D-analyses of the joint space for comparison of the femorotibial JSW of WB-CT and NWB-CT. However, a recent study performed a 3D approach of the foot and ankle for comparison of geometric measurements between WB-CT and NWB-CT 33 . The authors concluded that automated 3D analyses are more precise and reproducible than 2D assessments and better identify differences in bone configurations between WB-CT and NWB-CT 33 .…”

“…However, a recent study performed a 3D approach of the foot and ankle for comparison of geometric measurements between WB-CT and NWB-CT 33 . The authors concluded that automated 3D analyses are more precise and reproducible than 2D assessments and better identify differences in bone configurations between WB-CT and NWB-CT 33 . Furthermore, the femorotibial JSW has been compared previously with manual two-dimensional measurements obtained from a single image at a single position 12,13 .…”

Unique shape variations of hind and midfoot bones in flatfoot subjects—A statistical shape modeling approach

“…Another limitation is that scans were completed in a non‐weightbearing setting when results would have significantly differed in weightbearing (Kiaoka et al, 1998; Kido et al, 2011; de Cesar Netto et al, 2017). Indeed, weightbearing is known to emphasize altered joint configuration in flatfoot conditions, especially increasing the talocalcaneal angle into further valgus (Broos et al, 2021). However, there is not a linear relationship between loading of the foot and foot posture presentation, as the factors observed can non‐linearly increase or decrease (Broos et al, 2021).…”