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The Role of Weightbearing Computed Tomography Scan in Hallux Valgus
- Source :
- Foot & Ankle International. 42:287-293
- Publication Year :
- 2020
- Publisher :
- SAGE Publications, 2020.
-
Abstract
- Background: Hyperpronation of the first metatarsal in hallux valgus (HV) is poorly understood by conventional weightbearing radiography. We aimed to evaluate this parameter using weightbearing computed tomography (WBCT) and to understand its association with other standard measurements. Methods: Retrospective evaluation of WBCT and weightbearing radiographs (WBXRs) was performed for 20 patients with HV feet and 20 controls with no such deformity. Axial computed tomography images of both groups were compared for the first metatarsal pronation angle (alpha angle) and tibial sesamoid subluxation (TSS) grades. The HV angle (HVA), first-second intermetatarsal angle (IMA), first metatarsal-medial cuneiform angle (MMCA), Meary’s angle, and calcaneal pitch (CP) angle of the study and control groups were compared on both WBXR and the corresponding 2-dimensional images of WBCT. All measurements were independently performed by 1 musculoskeletal radiology fellow and 1 foot and ankle surgical fellow. Measurements were averaged and interobserver reliability was calculated. Results: The HV group demonstrated significantly higher values for TSS grade ( P < .001) but not for alpha angle ( P = .121) compared with controls. Likewise, significantly elevated HVA and IMA were noted in the HV group on both imaging modalities, while no such differences were observed for the CP angle. Higher MMCA and Meary’s angle in the HV group were evident only on WBXR (MMCA, P = .039; Meary’s, P = .009) but not on WBCT (MMCA, P = .183; Meary’s, P = .171). Among all, the receiver operating characteristic (ROC) curves demonstrated the greatest area under the curve (AUC) for HVA, followed by IMA. The alpha angle performed only just outside the range of chance (AUC, 0.65; 95% CI, 0.52-0.69). The Pearson’s correlations of the alpha angle, in the HV group, revealed a significant linear relationship with TSS grade and with HVA on WBXR, and only trended toward a weak linear relationship with IMA and with HVA on WBCT. Conclusion: The alpha angle, a measure of abnormal hyperpronation of the first metatarsal, was an independent factor that may coexist with other parameters in HV, but in isolation had limited diagnostic utility. “Abnormal” alpha angles were even observed in individuals without HV. Increases in IMA and MMCA were not necessarily associated with similar increases in alpha angle, despite moderate correlations with TSS grade and HVA on WBXR. Nevertheless, the WBCT was a useful method for assessing hyperpronation and guiding surgical management in individual cases. Level of Evidence: Level III, retrospective comparative study.
- Subjects :
- Radiography
Computed tomography
Weight-Bearing
03 medical and health sciences
0302 clinical medicine
medicine
Humans
Pronation
Orthopedics and Sports Medicine
Hallux Valgus
Radionuclide Imaging
Metatarsal Bones
Retrospective Studies
Orthodontics
030222 orthopedics
Tibia
medicine.diagnostic_test
biology
business.industry
First metatarsal
Reproducibility of Results
030229 sport sciences
biology.organism_classification
Calcaneus
Valgus
Surgery
business
Subjects
Details
- ISSN :
- 19447876 and 10711007
- Volume :
- 42
- Database :
- OpenAIRE
- Journal :
- Foot & Ankle International
- Accession number :
- edsair.doi.dedup.....25180e2e8d03fac92b531810e2555184
- Full Text :
- https://doi.org/10.1177/1071100720962398