Radiological Evaluation of a Preoperative First Metatarsal Realignment Test for Metatarsus Primus Varus and Hallux Valgus Correction by the Syndesmosis Procedure

Minimally Invasive Chevron Akin: Locking The Metatarsal-Cuneiform Joint

INTRODUCTION

Minimally Invasive Chevron Akin (MICA) can be used to treat hallux valgus (HV) associated with a hypermobility of the first metatarsal-cuneiform joint (1MTCJ). The aim of this study was to perform a radiographic analysis of the MICA, focused on evaluating the 1MTCJ.

METHODS

Forty patients (50 feet) with moderate to severe HV underwent a MICA procedure. Radiographic analysis included hallux valgus angle (HVA), intermetatarsal angles between the first and second rays (IMA), the intermetatarsal angle between the proximal fragment of the osteotomy and the second ray (IAPF) and the distance between a point 3 cm distal from the base of the second metatarsal and a point located at the same height for the first metatarsal base (Dist 1-2). The IAPF was compared with the preoperative IMA, and the other parameters were compared preoperatively and postoperatively. The radiographic complications were also recorded.

RESULTS

Most patients were female (92%). The mean age was 50.4 years (SD = 16.1) and the mean follow-up was 16.1 months (SD = 3.5). The average HVA improved from 32.5° to 7.3°, and the average IMA from 14.2° to 4.2°. The IAPF and Dist1-2 values showed an increase of 4.8° and 4.0 mm respectively. There were no radiographic complications. Conclusion. Minimally invasive Chevron Akin promotes a great correction of the moderate to severe HV conventional parameters and increase the transversal stability of the 1MTCJ fixing this joint as medial as possible.

LEVEL OF EVIDENCE

Level IV, case series.

Minimally Invasive Chevron Akin Osteotomy: Preoperative Planning Using the Radiographic First-Ray Squeeze Test

Background

Recognizing preoperative first-ray hypermobility is important to planning hallux valgus (HV) surgery. A recent study showed the minimally invasive chevron Akin (MICA) osteotomy increased varus displacement of the proximal fragment of the first metatarsal osteotomy. The present study aims to evaluate the ability of the radiographic first-ray squeeze test to predict the varus displacement of the proximal fragment of the first metatarsal osteotomy when performing the MICA procedure.

Methods

A prospective case series of patients with moderate to severe HV who underwent MICA was performed. The HV deformity correction was analyzed by comparing the preoperative and 12-week postoperative hallux valgus angle (HVA) and the intermetatarsal angle between the first and second rays (1-2 IMA). The ability of the radiographic first-ray squeeze test to predict the varus displacement of the first metatarsal was done by comparing the preoperative 1-2 IMA measured in the AP radiographic first-ray squeeze test (IMA-ST) with the intermetatarsal angle between the second metatarsal and the axis of the first metatarsal osteotomy proximal fragment (IAPF) taken 12 weeks postoperatively.

Results

Between July 2022 and May 2023, a total of 39 feet in 28 patients underwent MICA. The mean IMA improved from 13.8 (SD = 2.2) to 3.8 degrees (SD = 1.5) (P < .001), and the mean HVA improved from 27.8 (SD = 6.1) to 4.9 degrees (SD = 2.5) (P < .001). A linear regression analysis revealed that IMA-ST is highly associated with the 12 week assessed IAPF (P < .001).

Conclusion

The preoperative radiographic first-ray squeeze test appears to predict with high fidelity the varus displacement of the proximal fragment of the first metatarsal that can occur after the MICA procedure.Level of Evidence: Level III, prospective cohort study.

Radiographic Assessment of Relationship between Medial Cuneiform Obliquity and Hallux Valgus

The research results are inconsistent that assessing whether the increased obliquity of the distal articular surface of the medial cuneiform leads to an increase in hallux valgus angle. Thus, this study investigated the relationship between distal medial cuneiform obliquity and hallux valgus by measuring various angles in weightbearing anteroposterior radiographs of the foot. In total, 679 feet of 538 patients with the radiographs were included in the study. We measured radiographic parameters including hallux valgus angle, first to second intermetatarsal angle, metatarsus adductus angle, first metatarsus cuneiform angle, distal medial cuneiform angle, and first proximal metatarsal articular angle. The surface morphology (flat or curved) of the first tarsometatarsal joint was also recorded. Our results analysis revealed a weak negative correlation between distal medial cuneiform angle and both hallux valgus angle and first to second intermetatarsal angle, contrary to our assumption. So we believe that distal medial cuneiform angle was relatively constant and it cannot be used as a characteristic angle for quantifying hallux valgus. First metatarsus cuneiform angle was a characteristic indicator of hallux valgus and was positively correlated with its severity (p < .000), indicating that it can be used to measure the size of hallux valgus. It can also be used as a reference factor for the first metatarsal osteotomy in clinical bunion orthopedics. First tarsometatarsal joint morphology was unrelated to hallux valgus, whereas metatarsus adductus angle, and first proximal metatarsal articular angle should be considered in hallux valgus.

The Syndesmosis Procedure Correction of Hallux Valgus Feet Associated With the Metatarsus Adductus Deformity

Metatarsus adductus and hallux valgus are common foot deformities. Corrective surgery of hallux valgus feet with metatarsus adductus deformity can be challenging and experience a high deformity recurrence rate. The purpose of this study was to demonstrate if the syndesmosis procedure can correct such feet satisfactorily without osteotomies and arthrodesis. 75 hallux valgus feet in 45 patients with a Sgarlato's metatarsal adductus angle ≥15° were studied after having undergone the syndesmosis procedure for an average of 20.22 months. Their average preoperative intermetatarsal angle of 12.56° was improved to 6.00° (p < .001) and metatarsophalangeal angle from 35.61° to 23.46° (p < .001) significantly. Their average American Orthopedic Foot and Ankle Society's clinical scores improved significantly from 56.41 to 90.53 points (p < .001). Fifty-five feet (73.33%) had preoperative metatarsal calluses, and all but 3 had a noticeable reduction in severity. Forty-one patients (91.11%) were able to return to their desired activities and footwear. All relevant raw data formed this study, including x-ray and photographic images, were submitted as Supplementary Material for online viewing and reference. Despite the possible intrinsic rigidity of metatarsus adductus forefoot, this study demonstrated that hallux valgus feet with metatarsus adductus deformity could be corrected anatomically and functionally with the soft tissue syndesmosis procedure and without correcting the preexisting metatarsus adductus deformity. This study also supports the notion that the MA deformity accentuates hallux valgus alignment preoperatively and postoperatively, and possibly all feet in general.

[Radiographic study of relationship between medial cuneiform obliquity and simple hallux valgus]

OBJECTIVE

To investigate the relationship between hallux valgus and the indicators associated with medial cuneiform obliquity measured on feet weight-bearing anteroposterior X-ray films.

METHODS

Based on the feet weight-bearing anteroposterior X-ray films taken between January 2018 and February 2021 and met the criteria, the hallux valgus angle (HVA), intermetatarsal angle (IMA), metatarsus adductus angle (MAA), metatarsus cuneiform angle (MCA), distal medial cuneiform angle (DMCA), and proximal metatarsal articular angle (PMAA) were measured and the morphology of the first tarsometatarsal (TMT) were recorded. According to the HVA, the X-ray films were divided into normal group (HVA<15°) and hallux valgus group (HVA≥15°). The gender, age, sides, IMA, MAA, MCA, DMCA, PMAA, and the morphology of TMT were compared between groups. The influencing factors of HVA and IMA were analyzed by multivariate linear regression analysis.

RESULTS

X-ray films of 534 patients (679 feet) met the selection criteria and were included in the study. There were 220 males and 314 females, with an average age of 36 years (mean, 18-82 years). There were 154 cases (168 feet) in the normal group and 403 cases (511 feet) in the hallux valgus group. There were significant differences in gender and age between groups ( P<0.05), and no significant difference in the side ( P>0.05). The IMA, MAA, and MCA in the hallux valgus group were significantly bigger than those in the normal group ( P<0.05); the difference in DMCA between the two groups was not significant ( P>0.05). The TMT morphology of the two groups was mainly curved, and the difference in morphology classification was not significant ( P>0.05). PMAA measurement showed that there were 3 kinds of metatarsal shapes: adductive metatarsal, neutral metatarsal, and abductive metatarsal, the difference in metatarsal shapes between groups was not significant ( P>0.05). The PMAA of abductive metatarsal was significantly bigger in normal group than in hallux valgus group ( P<0.05), there was no significant difference in PMAA of adductive metatarsal between groups ( P>0.05). Multivariate linear regression analysis showed that age, MCA, and DMCA were the influencing factors of HVA ( P<0.05), and age, MAA, MCA, and DMCA were the influencing factors of IMA ( P<0.05).

CONCLUSION

The medial cuneiform obliquity is relatively constant and the DMCA can not be used as the characteristic angle to quantify hallux valgus. The morphology of TMT has no relationship with hallux valgus, while MAA, MCA, and PMAA are all factors to be considered, and MCA can be used as the characteristic angle to quantify hallux valgus.

Correlation between first tarsometatarsal joint mobility and hallux valgus severity

PURPOSE

The mobility of the first tarsometatarsal (TMT1) is said to be correlated to the severity of hallux valgus determined using both clinical and radiographic criteria. The sagittal mobility of the TMT1 joint can be evaluated objectively using a new ultrasound test, which quantifies it in the form of a unitless value (ratio of two measurements). The objective of this study was to describe the relationship between TMT1 mobility on an ultrasound test and hallux valgus severity. Hypothesis TMT1 joint mobility increases with hallux valgus severity.

PATIENTS AND METHODS

Forty-nine feet were included that were being treated for isolated hallux valgus and had no evidence of TMT1 hypermobility based on the dorsal drawer test. For each foot, the presence and intensity of load transfer (LT), the intermetatarsal angle (IMA), and the hallux valgus angle (HVA) were determined. Lastly, TMT1 mobility was evaluated with the ultrasound test.

RESULTS

Clinically, no LT was present in 20 feet; it was present only under M2 in 20 feet and reached at least M3 in the other nine feet. The mean IMA on radiographs was 14.6° and the mean HVA was 34.5°. The value of the ultrasound test was significantly different between the three groups of clinical hallux valgus severity: 1.17 with no LT, 1.31 with isolated M2 LT, and 1.72 when LT was at least at M3. Furthermore, this value was correlated with the IMA but not the HVA.

DISCUSSION

This study revealed a relationship between increased TMT1 mobility and hallux valgus severity based on clinical (LT) and radiographic (IMA) criteria. Thus, our working hypothesis is confirmed. However, there was no correlation between TMT1 mobility and HVA suggesting that this angle is less relevant for determining the severity of the condition. This is consistent with the classical pathophysiological concept of metatarsus primus varus where the hallux valgus originates in a metatarsus varus in the tarsometatarsal area.

CONCLUSION

The severity of hallux valgus is correlated with increased mobility of the TMT1 joint, which appears to have a causal role in this condition.

Normative Distribution of First Metatarsal Axial Rotation

BACKGROUND

First metatarsal (M1) axial rotation is recognized as a clinically relevant component of hallux valgus deformity. Methods to realign the M1 in 3 dimensions have been developed. One goal of these operations is to restore normal rotation of the first ray. The aim of this study is to provide estimates for the normal distribution of M1 rotation in patients without relevant anatomic pathology.

METHODS

Using stringent clinical and radiographic criteria, we evaluated a set of plain radiograph and weightbearing computed tomography (WBCT) images of 62 feet from a consecutive patient database. Subjects included had normal foot alignment without bunion symptoms. M1 rotation of each foot was measured using 2 unique methods (Saltzman et al and Kim et al methods). Measurement of rotation was performed by 2 observers from coronal WBCT images. Mean values and confidence intervals (CIs) of M1 rotation were calculated for each method. Inter- and intraobserver reliability values were also reported.

RESULTS

Mean M1 rotation values of 2.1 degrees (95% CI: 0.9-3.4) and 6.1 degrees (95% CI: 4.4-7.8) were identified using the Saltzman et al and Kim et al methods, respectively. Inter- and intraobserver reliability values were interpreted as excellent for both methods.

CONCLUSION

In this study, we describe the natural distribution of the M1 axial rotation in subjects without bunion or other identifiable bony foot deformities. This information should provide a normative reference for surgeons correcting rotational issues of the first metatarsal.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

First Metatarsal Rotation in Hallux Valgus Deformity

Rotation of the first metatarsal (M1) as a potential etiological factor of hallux valgus (HV) deformity was described relatively early in the description of HV pathoanatomy. However, because biplanar radiographs have been the standard method for imaging HV, clinicians primarily developed measurement methods and corrective operations confined to 2 dimensions, medial-lateral and inferior-superior. Recently, as our understanding of HV pathoanatomy has further developed, aided in part by advanced imaging technology, M1 rotation about its axis ("axial rotation") and its implications for HV deformity and treatment has reemerged. The goal of this review is to summarize M1 rotation in HV from a historical perspective, to present the current understanding of its potential role in the etiology/pathogenesis of HV, and to summarize relevant imaging and operative considerations with respect to M1 rotation.Level of Evidence: Level III, systematic review.

The metatarsaus adductus effect by the syndesmosis procedure for hallux valgus correction

Aims

The purpose of this study is to examine the adductus impact on the second metatarsal by the nonosteotomy nonarthrodesis syndesmosis procedure for the hallux valgus deformity correction, and how it would affect the mechanical function of the forefoot in walking. For correcting the metatarsus primus varus deformity of hallux valgus feet, the syndesmosis procedure binds first metatarsal to the second metatarsal with intermetatarsal cerclage sutures.

Methods

We reviewed clinical records of a single surgical practice from its entire 2014 calendar year. In total, 71 patients (121 surgical feet) qualified for the study with a mean follow-up of 20.3 months (SD 6.2). We measured their metatarsus adductus angle with the Sgarlato’s method (SMAA), and the intermetatarsal angle (IMA) and metatarsophalangeal angle (MPA) with Hardy’s mid axial method. We also assessed their American Orthopaedic Foot & Ankle Society (AOFAS) clinical scale score, and photographic and pedobarographic images for clinical function results.

Results

SMAA increased from preoperative 15.9° (SD 4.9°) to 17.2° (5.0°) (p < 0.001). IMA and MPA corrected from 14.6° (SD 3.3°) and 31.9° (SD 8.0°) to 7.2° (SD 2.2°) and 18.8° (SD 6.4°) (p < 0.001), respectively. AOFAS score improved from 66.8 (SD 12.0) to 96.1 (SD 8.0) points (p < 0.001). Overall, 98% (119/121) of feet with preoperative plantar calluses had them disappeared or noticeably subsided, and 93% (113/121) of feet demonstrated pedobarographic medialization of forefoot force in walking. We reported all complications.

Conclusion

This study, for the first time, reported the previously unknown metatarsus adductus side-effect of the syndesmosis procedure. However, it did not compromise function restoration of the forefoot by evidence of our patients' plantar callus and pedobarographic findings.

Level of Clinical Evidence: III

Cite this article: Bone Jt Open 2021;2(3):174–180.