Cardan angle rotation sequence effects on first‐metatarsophalangeal joint kinematics: implications for measuring hallux valgus deformity

Abstract

BackgroundThere currently are no recommended standards for reporting kinematics of the first-metatarsophalangeal joint. This study compared 2 different rotation sequences of Cardan angles, with implications for understanding the measurement of hallux valgus deformity.MethodsThirty-one women (19 hallux valgus; 12 controls) participated. All were scanned in an open-upright magnetic resonance scanner, their foot posed to simulate the gait conditions of midstance, heel-off, and terminal stance. Using computer processes, selected tarsals were reconstructed into virtual bone models and embedded with principal-axes coordinate systems, from which the rotation matrix between the hallux and first metatarsal was decomposed into Cardan angles. Joint angles were then compared using a within factors (rotation sequence and gait condition) repeated-measures analysis of variance (ANOVA).ResultsOnly the transverse plane-first sequence consistently output incremental increases of dorsiflexion and abduction across gait events in both groups. There was an interaction (F ≥ 25.1; p < 0.001). Follow-up comparisons revealed angles were different (p < 0.05) at terminal stance.ConclusionsDifferent rotation sequences yield different results. Extracting the first rotation in the transverse plane allows for the resting alignment of the hallux to deviate from the sagittal plane. Therefore, representing first-metatarsophalangeal joint kinematics with the transverse plane-first rotation sequence may be preferred, especially in cases of hallux valgus deformity.

An Imaged-Based Three-Dimensional Study of First Metatarsal Protrusion Distance in Women with and Without Hallux Valgus

“…44 This research had further limitations. The group size was kept small 9,29,31 due to the high cost of MR imaging. This limited the generalizability of the results, and reduced the power of statistical tests to detect group differences.…”

“…Further details of the scanning protocol have been reported elsewhere. 9,29,31 Images were imported into Mimics 17.01 (Materialise, Leuven, Belgium) software for reconstruction. The virtual bone models displayed for analysis in this study were the first metatarsal, second metatarsal, and navicular.…”

“…The virtual bone models displayed for analysis in this study were the first metatarsal, second metatarsal, and navicular. Additional bones were reconstructed for analysis in previous work, 9,29,31 and the hallux angle and intermetatarsal angles were quantified ( Table 1). The size of these two Figure 1.…”

“…19 Critical to the measurement of MPD, the first metatarsal, second metatarsal, and navicular were each embedded with a principal axis coordinate system. 34 The orthogonal coordinate systems defined the spatial orientation of the bone models, 9,29,31 such that the longitudinal axis ( Fig. 1) of the coordinate system located the distal most point of each bone.…”

“…7 The principle underlying this area of research is that when the first metatarsal protrudes distal to the second metatarsal, the load carried by the hallux is increased. 8 This increase in load, the trajectory of the center of pressure, 9 and the compression of shoewear during gait propulsion 5,10 culminates to push the hallux laterally into valgus deformity. A meta-analysis by Nix et al 11 evaluated the literature reporting first metatarsal protrusion in patients with hallux valgus.…”