Distal Metatarsal Articular Angle in Hallux Valgus Deformity. Fact or Fiction? A 3-Dimensional Weightbearing CT Assessment

Abstract

Background The Distal Metatarsal Articular Angle (DMAA) was previously described as an increase in valgus deformity of the distal articular surface of the first metatarsal (M1) in hallux valgus (HV). Several studies have reported poor reliability of this measurement. Some authors have even called into question its existence and consider it to be the consequence of M1 pronation resulting in projection of the round-shaped lateral edge of M1 head. Our study aimed to compare the DMAA in HV and control populations, before and after computer correction of M1 pronation and plantarflexion with a dedicated weightbearing CT (WBCT) software. We hypothesized that after computerized correction, DMAA will not be increased in HV compared to controls. Methods: We performed a retrospective case-control study including 36 HV and 20 control feet. In both groups, DMAA was measured as initially described on conventional radiographs (XR-DMAA) and WBCT by measuring the angle between the distal articular surface and the longitudinal axis of M1. Then, the DMAA was measured after computerized correction of M1 plantarflexion and coronal plane rotation using the α angle (3d-DMAA). Results: The XR-DMAA and the 3d-DMAA showed higher significant mean values in HV group compared to controls (respectively 25.9 ± 7.3 vs 7.6 ± 4.2 degrees, P < .001, and 11.9 ± 4.9 vs 3.3 ± 2.9 degrees, P < .001). Comparing a small subset of precorrected juvenile HV (n=8) and nonjuvenile HV (n=28) demonstrated no significant difference in the measure DMAA values. On the other hand, the α angle was significantly higher in the juvenile HV group (21.6 ± 9.9 and 11.4 ± 3.7 degrees; P = .0046). Conclusion: Although the valgus deformity of M1 distal articular surface in HV is overestimated on conventional radiographs, comparing to controls showed that an 8.6 degrees increase remained after confounding factors’ correction. Clinical Relevance: After pronation computerized correction, an increase in valgus of M1 distal articular surface was still present in HV compared to controls. Level of Evidence: Level III, retrospective case-control study.

Coronal Plane Rotation of the Medial Column in Hallux Valgus: A Retrospective Case-Control Study

“…We previously reported an increase in M1 head pronation relative to the ground in HV patients. 7 In the present study, individual measurements of the rotation of the bones composing the medial column revealed an increase in pronation of M1 intrinsic torsion and first tarsometatarsal joint position in HV compared with controls, confirming our hypothesis. This pronation was paradoxically and partially counterbalanced by an increase in supination of the first naviculocuneiform joint.…”

“…This was a retrospective case-control study, approved by the institutional review board (IRB 201904825), that used the same cohort of our previous article, including 36 HV and 20 control feet (matched for gender age and body mass index). 7 We previously performed and published a cadaveric study to assess the relevance and the accuracy of several weightbearing CT coronal plane rotation measurements throughout the medial column of the foot. 4 In this study, coronal rotational profiles of the navicular, medial cuneiform, M1 at base and midshaft levels, as well as the metatarsal pronation angle and α angles were established.…”

Minimally Invasive Chevron-Akin for Correction of Moderate and Severe Hallux Valgus Deformities: Clinical and Radiologic Outcomes With a Minimum 2-Year Follow-up

“…There is growing interest in the use of minimally invasive surgical techniques (MIS) for the treatment of hallux valgus (HV), with an increasing number of published studies including clinical series, radiologic validations, cadaveric studies, comparative studies, and technical reports on MIS techniques. 1,4,[8][9][10][15][16][17][18][19][20][21]23,[26][27][28][29][30][31][32][33][34][35][36][39][40][41][42][43]45,55,[59][60][61][62][63][64]66,70 Five recent systematic reviews concluded that MIS is a safe and reliable technique for hallux valgus correction. 6,11,28,44,65 Among the procedures to treat HV, the distal chevron metatarsal osteotomy was first described in 1962 and remains a widely accepted technique.…”

Side-to-Side Difference of Metatarsal Rotation in Normal Individuals

“…[5][6][7]10 It has been shown that there are significantly higher levels of first metatarsal pronation in feet with hallux valgus deformity as compared to controls. 3 Further, it has been shown that correction of pronation in hallux valgus results in significantly improved PROMIS physical function scales and reduced recurrence rates compared to no correction of rotation in the coronal plane. 1 Therefore, addressing first metatarsal pronation is an area of topical interest as it may improve outcomes in operative correction of hallux valgus.…”