Metatarsal Pronation in Hallux Valgus Deformity: A Review

Outcome comparison of minimally invasive proximal and distal chevron Akin osteotomies in patients with severe hallux valgus deformity: A randomized prospective study

PURPOSE

To date, the surgical treatment of severe hallux valgus deformity remains challenging despite the various methods presented. This study aimed to compare the effectiveness of minimally invasive distal chevron Akin osteotomies (d-MICA) and minimally invasive proximal chevron Akin osteotomies (p-MICA) in correcting severe hallux valgus deformities.

METHODS

This prospective follow-up study included patients randomly assigned to undergo p-MICA or d-MICA for hallux valgus deformities with a preoperative hallux valgus angle (HVA) ≥ 40° and/or a first to second intermetatarsal angle (IMA) ≥ 16°. After a minimum follow-up period of two years, we compared various clinico-radiographic parameters of patients whose HVA exceeded 15° at the final follow-up.

RESULTS

In the p-MICA and d-MICA groups, seven of 40 cases (17.5%) and 16 of 41 cases (39.0%), respectively, exhibited HVA > 15° at the final follow-up (P = 0.048). The preoperative parameters showed no significant differences. However, at the first weight-bearing assessment, the HVA, IMA, and relative second metatarsal length were significantly smaller, and the distal metatarsal articular angle (DMAA) was greater in the p-MICA group (all P < 0.05) compared with the d-MICA group. Postoperatively, both groups exhibited significant decreases in HVA and IMA at the final follow-up (P < 0.001 for all parameters). The p-MICA group showed no significant changes in DMAA and the relative length of the second metatarsal (P = 0.253 and 0.185, respectively). However, the d-MICA group showed a significant decrease in DMAA (P < 0.001) and an increase in the relative length of the second metatarsal at the final follow-up (P = 0.01).

CONCLUSIONS

p-MICA and d-MICA procedures demonstrated effective correction potential for severe hallux valgus deformities; however, the d-MICA procedure exhibited a notably higher incidence of unsatisfactory correction at the final follow-up than p-MICA. Therefore, d-MICA may be less predictable in achieving successful outcomes than p-MICA in treating severe hallux valgus deformities.

Radiologic and Clinical Outcomes of the Dovetailed Notch Scarf Osteotomy for Correcting the First Metatarsal Pronation in Moderate to Severe Hallux Valgus Deformity: A Comparative Study

BACKGROUND

The traditional scarf osteotomy (TSO) has limited ability to correct the first metatarsal pronation. A novel modification that we refer to as a "dovetailed notch scarf osteotomy" (DNSO) has been developed to enhance the ability to correct coronal plane pronation. The study aimed to observe and compare TSO to DNSO in the treatment of moderate to severe hallux valgus deformity.

METHODS

This retrospective study included 78 feet that had a TSO and 105 feet that had a DNSO. Minimum follow-up was 24 months. Weightbearing computed tomography (WBCT) and weightbearing anterior-posterior (AP) radiographs were taken preoperatively and at the last follow-up. We measured the intermetatarsal angle (IMA), hallux valgus angle, distal metatarsal articular surface angle on AP radiographs and first metatarsal coronal pronation angle (α angle), tibial sesamoid coronal grading, and first metatarsal length on WBCT. Clinical assessment was done using visual analog scale (VAS), American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scale, Foot and Ankle Ability Measure (FAAM), and the 36-Item Short Form Health Survey (SF-36). The occurrence of postoperative complications was also documented.

RESULTS

The DNSO group exhibited a significantly higher correction amount of α angle and IMA (14.3 ± 9.9 and 10.3 ± 4.6 degrees) than the TSO group (8.6 ± 5.9 and 5.4 ± 5.9 degrees) during the final follow-up assessment (P < .05).The DNSO group (10.1 [8.0-12.0] degrees and 4.8 [3.9-5.6] degrees) demonstrated significantly smaller α angle and IMA compared with the TSO group (4.8 [3.9-5.6] degrees and 9.5 [7.5-11.5] degrees) at 24 months postsurgery (P < .05). The postoperative FAAM activities of daily living and SF-36 physical functioning scores were significantly higher in the DNSO group (97.2 ± 3.3 and 95.7 ± 4.4 points) compared with the TSO group (92.3 ± 3.3 and 87.7 ± 8.7 points) (P < .05). Additionally, hallux varus occurred in 1 case in the DNSO group, whereas 4 cases were observed in the TSO group.

CONCLUSION

Two osteotomy methods can effectively correct moderate to severe hallux valgus deformity. Compared with the TSO, the DNSO has stronger correction ability. The most crucial aspect lies in its controllability when correcting first metatarsal pronation and addressing IMA.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Impact of Sesamoid Coverage on Clinical Foot Function Following Fourth-Generation Percutaneous Hallux Valgus Surgery

Background

The impact of pronation and sesamoid coverage on clinical outcomes following percutaneous hallux valgus surgery are not currently known. The aim of this study was to investigate if sesamoid coverage was associated with worse clinical outcomes at 12-month follow-up following percutaneous hallux valgus surgery.

Methods

Retrospective comparative observational study of clinical and radiographic outcomes based on a previously published prospective dataset. Patients were stratified into 3 cohorts based on the degree of sesamoid coverage (normal, mild, or moderate) on 12-month weightbearing radiographs following fourth-generation percutaneous hallux valgus surgery. Primary outcome was a validated patient-reported outcome measure (PROM), the Manchester-Oxford Foot Questionnaire (MOXFQ). Secondary outcomes included Euroqol-5D, VAS Pain, and radiographic deformity correction.

Results

Forty-seven feet underwent primary fourth-generation HV surgery and were stratified into 3 cohorts. There were 19, 16, and 12 feet in the normal, mild, and moderate cohorts respectively. There was no significant difference in either pre- or postoperative foot function (all MOXFQ domains, P > .05) or health-related quality of life (EQ-5D Index or VAS, P > .05). The MOXFQ Index preoperatively was as follows: normal cohort, 56.1 ± 26.9; mild cohort, 54.1 ± 17.9; and severe cohort, 49.6 ± 23.8; and postoperatively was as follows: normal cohort, 15.6 ± 21.5; mild cohort, 11.4 ± 15.5; and severe cohort, 11.4 ± 13.6 (P = .737-.908). There was significantly worse hallux valgus angle (HVA) and intermetatarsal angle (IMA) between the cohorts (P < .01). Although HVA and IMA were corrected to normal parameters following surgery in all cohorts, there was a significantly worse postoperative HVA in the moderate sesamoid coverage (5.3 ± 3.9 vs 7.9 ± 5.3 vs 11.4 ± 3.7, P < .01); however, IMA was not significantly different (3.4 ± 2.2 vs 4.1 ± 2.7 vs 5.2 ± 2.9, P = .168).

Conclusion

This study found that cases where the sesamoids were not reduced had a poorer correction and had worse preoperative deformity. Clinical outcomes and foot function following fourth-generation percutaneous hallux valgus surgery were not affected by sesamoid coverage at the 12-month follow-up. The long-term implications in the difference in radiographic deformity between the 3 cohorts are not known, and further work should explore the relationship of first ray pronation and sesamoid position, particularly with regard to recurrence.

Level of evidence

Level III, retrospective comparative study of prospectively collected data.

Automated decision support for Hallux Valgus treatment options using anteroposterior foot radiographs

BACKGROUND

Assessment of the potential utility of deep learning with subsequent image analysis to automate the measurement of hallux valgus and intermetatarsal angles from radiographs to serve as a preoperative aid in establishing hallux valgus severity for clinical decision-making.

AIM

To investigate the accuracy of automated measurements of angles of hallux valgus from radiographs for further integration with the preoperative planning process.

METHODS

The data comprises 265 consecutive digital anteroposterior weightbearing foot radiographs. 181 radiographs were utilized for training (161) and validating (20) a U-Net neural network to achieve a mean Sørensen–Dice index > 97% on bone segmentation. 84 test radiographs were used for manual (computer assisted) and automated measurements of hallux valgus severity determined by hallux valgus (HVA) and intermetatarsal angles (IMA). The reliability of manual and computer-based measurements was calculated using the interclass correlation coefficient (ICC) and standard error of measurement (SEM). Inter- and intraobserver reliability coefficients were also compared. An operative treatment recommendation was then applied to compare results between automated and manual angle measurements.

RESULTS

Very high reliability was achieved for HVA and IMA between the manual measurements of three independent clinicians. For HVA, the ICC between manual measurements was 0.96-0.99. For IMA, ICC was 0.78-0.95. Comparing manual against automated computer measurement, the reliability was high as well. For HVA, absolute agreement ICC and consistency ICC were 0.97, and SEM was 0.32. For IMA, absolute agreement ICC was 0.75, consistency ICC was 0.89, and SEM was 0.21. Additionally, a strong correlation (0.80) was observed between our approach and traditional clinical adjudication for preoperative planning of hallux valgus, according to an operative treatment algorithm proposed by EFORT.

CONCLUSION

The proposed automated, artificial intelligence assisted determination of hallux valgus angles based on deep learning holds great potential as an accurate and efficient tool, with comparable accuracy to manual measurements by expert clinicians. Our approach can be effectively implemented in clinical practice to determine the angles of hallux valgus from radiographs, classify the deformity severity, streamline preoperative decision-making prior to corrective surgery.

A modified minimally invasive osteotomy for hallux valgus enables reduction of malpositioned sesamoid bones

BACKGROUND

The current minimally invasive distal metatarsal osteotomy for hallux valgus (HV) is V-shaped, which prevents the correction of the rotational metatarsal head deformity and reduction of the sesamoid bones. We sought to determine the optimal method for sesamoid bone reduction during HV surgery.

METHODS

We reviewed the medical records of 53 patients who underwent HV surgery between 2017 and 2019 using one of three techniques: open chevron osteotomy (n = 19), minimally invasive V-shaped osteotomy (n = 18), and a modified straight minimally invasive osteotomy (n = 16). The sesamoid position was graded using the Hardy and Clapham method on weight-bearing radiographs.

RESULTS

When compared to open chevron and V-shaped osteotomies, the modified osteotomy resulted in significantly lower postoperative sesamoid position scores (3.74 ± 1.48, 4.61 ± 1.09, and 1.44 ± 0.81, respectively, P < 0.001). Furthermore, the mean change in postoperative sesamoid position score was greater (P < 0.001).

CONCLUSION

The modified minimally invasive osteotomy was superior to the other two techniques in correcting HV deformity in all planes, including sesamoid reduction.

How Might Consideration of Cell Polarity Affect Daily Therapeutic Practices?A Literature Review:

BACKGROUND

In addition to biochemical gradients and transcriptional networks, cell behaviour is controlled by endogenous bioelectrical signals resulting from the action of ion channels and pumps. Cells are regulated not only by their own membrane resting potential (Vmem) but also by the Vmem of neighbouring cells, establishing networks through electrical synapses known as gap junctions. V mem is the primary factor in producing a polarity that can regulate cell assimilation of various substances. This article aimed to examine how cell polarity can change and how variations in cell polarity may lead to clinical demonstrations.

MATERIALS AND METHODS

Using Cochrane Central, PubMed, Scopus, Web of Science (WOS), and Embase, a comprehensive qualitative literature review was conducted from February 1, 2018, to February 1, 2023, to identify studies addressing bioelectric, cell polarity, and electroceuticals in patients with foot and ankle problems.

RESULTS

Out of 1,281 publications, 27 were included. One study investigated bioelectric wound-healing. Twenty-five studies examined bioelectric nerve cell growth, whereas one study evaluated bioelectricity-induced cellular differentiation in the treatment of arteriopathies.

CONCLUSION

The author of this systematic review support addressing the predisposing factors and healing impediments for a disease, thereby enhancing the healing process and reducing the likelihood of recurrence or parallel conditions. This method of treatment has provided a summary of evidence indicating that cell polarity could be addressed for the treatment and prevention of most if not all, foot and ankle problems. However, owing to the limitations of V mem and bioelectricity measurement and the direct or indirect involvement of genetics and chemical gradients, further studies are required to confirm these results.

Global research trends and hotspots analysis of hallux valgus: A bibliometric analysis from 2004 to 2021

Background

Hallux valgus (HV) is a common foot and ankle surgery disease. The correction of HV deformity relies on a highly challenging surgical treatment. Thus, widely adopted evidence-based clinical guidelines are still needed to guide the selection of the most appropriate interventions. Recently, the study of HV has been growing and scholars are increasingly paying particular attention to this area. However, bibliometric literature remains lacking. Therefore, this study aims to reveal the hotspots and future research trends in HV via bibliometric analysis to fill this knowledge gap.

Methods

Literature related to HV from 2004 to 2021 was retrieved from the Science Citation Index Expanded (SCI-expanded) of the Web of Science Core Collection (WoSCC). Quantitative and qualitative analyses of scientific data are performed using software such as CiteSpace, R-bibliometrix, and VOSviewer.

Results

A total of 1,904 records were identified for analysis. The United States had the most number of published articles and total citations. Thus, the United States has made an essential contribution to the field of HV. Meanwhile, La Trobe University in Australia was the most productive institution. Menz HB and Foot &amp; Ankle International were the most influential authors and the most popular journals among researchers, respectively. In addition, “older people,” “chevron osteotomy,” “Lapidus,” and “hallux rigidus” have always been the hotspots of attention. Changes and developments in the surgery of HV have gained researchers' interest. Future research trends are more focused on “radiographic measurement,” “recurrence,” “outcome,” “rotation,” “pronation,” and “minimally invasive surgery.” Thus, focusing on these subject directions can facilitate academic progress and provide the possibility of better treatments for HV.

Conclusion

This study summarizes the hotspots and trends in the field of HV from 2004 to 2021, which will provide researchers with an updated view of essential information and somehow guide future research.

Sesamoid View Weightbearing Radiography vs Weightbearing Computed Tomography in the Measurement of Metatarsal Pronation Angle

BACKGROUND

First metatarsal pronation angle (MPA) is increasingly relevant in the management of hallux valgus and is assessed on weightbearing computed tomography (WBCT) and sesamoid-view weightbearing radiography (WBR). The purpose of this study is to compare MPA measured by WBCT against WBR to determine if any systematic discrepancy in MPA measurement exists between the 2 modalities.

METHODS

A total of 40 patients with 55 feet were included for study. MPA was measured in all patients by 2 independent readers on both WBCT and WBR with an appropriate washout period between measurement modalities. Mean MPA by WBCT and WBR were analyzed; interobserver reliability was calculated with an intraclass correlation coefficient (ICC) value.

RESULTS

Mean MPA as measured by WBCT was 3.7 ± 7.9 degrees (95% CI, 1.6-5.9; range -11.7 to 20.5). Mean MPA measured on WBR was 3.6 ± 8.4 degrees, (95% CI, 1.4-5.8; range -12.6 to 21.4). There was no difference in MPA as measured by WBCT compared to WBR (P = .529). Interobserver reliability was excellent with an ICC of 0.994 for WBCT and 0.986 for WBR.

CONCLUSION

Measurement of first MPA by WBCT and WBR was not significantly different. In our cohort of patients with and without forefoot pathology, we found that either sesamoid view weightbearing radiographs or weightbearing CT can be used reliably to measure first MPA and will generate similar values.

LEVEL OF EVIDENCE

Level IV, case series.

Investigation on the site of coronal deformities in Hallux valgus

Hallux valgus (HV) is a common foot deformity that is more prevalent in females, characterised by abnormal adduction of the first metatarsal (MT) and valgus deviation of the phalanx on the transverse plane. Increasing evidence indicates that HV is more than a 2D deformity but a 3D one with rotational malalignment. Pronation deformity is seen during clinical examination for HV patients, but the exact origin of this rotational deformity is still unknown. Some attribute it to first tarsometatarsal (TMT) joint rotation, while others attribute it to intra-metatarsal bony torsion. In addition, the correlation between the rotational and transverse plane deformity is inconclusive. Identifying the origin of the rotational deformity will help surgeons choose the optimal surgical procedure while also enhancing our understanding of the pathophysiology of HV. This study aims to (1) develop an objective method for measuring the first MT torsion and first TMT joint rotation; (2) investigate the exact location of the coronal deformity in HV; (3) investigate the relationship between the severity of deformity on the transverse and coronal planes as well as the correlation between deformity severity and foot function/symptoms in HV. Age-matched females with and without HV were recruited at the Foot and Ankle Clinic of the Department of Orthopaedics and Traumatology. Computed tomography was conducted for all subjects with additional weight-bearing dorsal-plantar X-ray examination for HV subjects. Demographic information of all subjects was recorded, with symptoms and functions related to HV evaluated. The intra-class correlation was used to explore the relationship between deformities on different planes and the deformity severity and functional outcomes, respectively. An Independent t-test was used to compare joint rotation and bone torsion degrees. TMT joint rotation is significantly correlated with foot function. HV patients had more TMT joint rotation but not MT torsion compared to normal controls. No relationship was found between the coronal rotation and the 1,2-intermetatarsal angle (IMA) or Hallux valgus angle (HVA) on the transverse plane. Our results indicate that coronal deformities in HV may originate from TMT joint rotation. In addition, the severity of the TMT joint coronal rotation correlates with worse foot function; thus, multi-plane assessment and examination will be necessary for more precise surgical correction.

Association of Hallux Valgus with Degenerative Spinal Diseases: A Population-Based Cohort Study

Background: Although hallux valgus is known to cause lower-back pain, the association between hallux valgus and spinal degenerative disease remains unclear. Methods: A retrospective cohort study was conducted between 1 January 2000 and 31 December 2015 using data from the Longitudinal Health Insurance Database in Taiwan. After propensity score matching for age, sex, and some potential comorbidities, 1000 individuals newly diagnosed with hallux valgus were enrolled in the study group, while 1000 individuals never diagnosed with hallux valgus served as the control group. Both groups were followed up until 2015 to evaluate the incidence of hallux valgus. Kaplan-Meier analysis was used to determine the cumulative incidence of hallux valgus, while the Cox proportional hazard model was adopted to estimate the hazard ratio (HR) and adjusted hazard ratio (aHR) with 95% confidence intervals (CIs). Results: The incidence densities of spinal degeneration in the hallux valgus and non-hallux valgus groups were 73.10 and 42.63 per 1000 person-years, respectively. An increased risk of spinal degenerative changes was associated with hallux valgus (adjusted HR = 1.75, 95% CI = 1.50−2.05). Age- and sex-stratified analyses showed a significantly higher risk of spinal degeneration in the hallux valgus group. Moreover, sub-outcome evaluations revealed significantly higher risks of spondylosis (aHR = 2.01, 95% CI = 1.55−2.61), intervertebral disorder (aHR = 2.27, 95% CI = 1.62−3.17), and spinal stenosis (aHR = 1.24, 95% CI = 1.47−1.76). There was also an increased risk of spinal degenerative change in those with hallux valgus without surgical intervention (aHR = 1.95, 95% CI = 1.66−2.99, p < 0.001). Conclusions: Hallux valgus was associated with increased risk of degenerative spinal changes and other spinal disorders.

Clinical and Radiographic Outcomes of Percutaneous Third-Generation Double First Metatarsal Osteotomy Combined With Closing-Wedge Proximal Phalangeal Osteotomy for Moderate and Severe Hallux Valgus

BACKGROUND

The treatment for severe hallux valgus deformity presents a challenge with high risk of complications. Third generation MIS techniques have increased their publications in recent years. The aim was to compare clinical and radiologic outcomes in moderate and severe cases and report minor and major complications.

METHODS

Retrospective series of cases with prospective data collection of 156 consecutive feet that underwent percutaneous double first metatarsal osteotomy (PEDO) and first phalanx osteotomy between 2008 and 2019 for moderate (hallux valgus angle [HVA] between ≥20 and <40 degrees and/or intermetatarsal angle [IMA] <16 degrees) and severe (HVA ≥40 degrees and/or IMA ≥16 degrees) hallux valgus deformities. Primary outcomes included radiographic and clinical parameters. Secondary outcomes included minor and major complications.

RESULTS

A total of 156 procedures were performed in 128 patients. Mean age was 54.3 years (SD 14.3) (range, 19-82 years), median follow-up was 22.6 months (range, 12-96 months). Radiographic changes pre- to postoperation were as follows: HVA changed from 38.2 (SD 10.1) degrees to 11.2 (SD 8.3) degrees (P < .001), IMA from 14.7 (SD 3.2) degrees to 7.9 (SD 3.7) degrees (P < .001), and distal articular metatarsal angle from 19.7 (SD 6.3) degrees to 8.8 (SD 5.7) degrees (P < .001) after PEDO technique. Clinical changes pre- to postoperation were as follows: American Orthopaedic Foot & Ankle Society ankle-hindfoot scale scores improved from 47.3 (SD 16.5) to 87 (SD 11.6) (P < .001) and visual analog scale scores from 5 (2.7) to 0.9 (1.3) (P < .001). The satisfaction rate was 97% in the total sample. Recurrence rate (HVA ≥20 degrees) was 7.7%. Hallux varus (HVA <0 degrees) occurred in 5.8%, acute osteomyelitis in 1.3%, partial avascular necrosis in 0.6%, screw removal in 0.6%, and reoperation in 1.9%. No nonunion was observed.

CONCLUSION

Clinical and radiographic parameters improved significantly, with a minimum of 12 months of follow-up in moderate and severe hallux valgus. Long experience in percutaneous surgery and specific instruments are needed for this technique. Recurrence was linked to preoperative HVA ≥40 degrees and postoperative tibial sesamoid position; Hallux varus was linked to lateral soft tissue release.

LEVEL OF EVIDENCE

Level IV, case series.

Identification of radiographic characteristics associated with pain in hallux valgus patients: A preliminary machine learning study

Objective

To investigate the association between the structural deformity and foot pain in hallux valgus (HV) patients using a multi-variate pattern analysis (MVPA) approach.

Methods

Plain radiographic metrics were calculated from 36 painful and 36 pain-free HV feet. In analysis 1, univariate analyses were performed to investigate the clinical and radiographic differences between painful and pain-free HV. In analysis 2, we investigated the pattern differences for radiographic metrics between these two groups using a MVPA approach utilizing a support vector machine. In analysis 3, sequential backward selection and exhaustive search were performed as a feature-selection procedure to identify an optimal feature subtype. In analysis 4, hierarchical clustering analysis was used to identify the optimal radiographic HV subtype associated with pain in HV.

Results

We found that: (1) relative to feet with pain-free HV, the painful ones exhibited a higher hallux valgus angle, i.e., the magnitude of distal metatarsal and phalangeal deviation; (2) painful HV could be accurately differentiated from pain-free HV via MVPA. Using sequential backward selection and exhaustive search, a 5-feature subset was identified with optimal performance for classifying HV as either painful or pain-free; and (3) by applying hierarchical clustering analysis, a radiographic subtype with an 80% pain incidence was identified.

Conclusion

The pain in HV is multifactorial and associated with a radiographic pattern measured by various angles on plain radiographs. The combination of hallux valgus angle, inter-phalangeal angle, distal metatarsal articular angle, metatarsal cuneiform angle and metatarsal protrusion distance showed the optimal classification performance between painful and pain-free HV.

Pronation on weightbearing radiographs does not correlate with pronation from weightbearing CT scans

INTRODUCTION

In hallux valgus (HV), first metatarsal pronation is increasingly recognized as an important aspect of the deformity. The purpose of this study was to compare pronation in HV patients determined from the shape of the lateral head of the first metatarsal on AP weightbearing radiographs with pronation calculated from weightbearing CT (WBCT) scans.

METHODS

Patients were included in this study if they had preoperative and 5-month postoperative WBCT scans and corresponding weightbearing AP radiographs of the affected foot. Pronation of the first metatarsal on WBCT scans was measured using a 3D CAD model and the alpha angle and categorized into four groups on radiographs. Association between pronation groups on radiographs and WBCT scans was determined using Spearman correlation coefficients (r_s) and by comparing mean WBCT pronation of the first metatarsal between plain radiograph pronation groups.

RESULTS

Agreement between the two observers' pronation on radiographs was good (k = 0.634) and moderate (k = 0.501), respectively. There was no correlation between radiographic pronation and the 3D CAD model (r_s < 0.15). Preoperatively, there was weak correlation between the alpha angle and the radiographic pronation groups (r_s = 0.371, P = 0.048) although this relationship did not hold postoperatively (r_s = 0.330, P = 0.081). There was no difference in mean pronation calculated on WBCT scans between the plain radiographic groups.

CONCLUSION

Pronation of the first metatarsal measured on weightbearing AP radiographs had moderate interobserver agreement and was only weakly associated with pronation measured from WBCT scans. These results suggest that first metatarsal pronation measured on weightbearing radiographs is not a substitute for pronation measured on WBCT scans.

LEVEL OF EVIDENCE

III, retrospective cohort study.

Repeatability of Weightbearing Computed Tomography Measurement of First Metatarsal Alignment and Rotation

BACKGROUND

Weightbearing computed tomography (WBCT) can be used to assess alignment and rotation of the first metatarsal. It is unknown whether these measures remain consistent on sequential WBCTs in the same patient when a patient's standing position may be different. The aim of this study was to establish the repeatability (test-retest) of measurements of first metatarsal alignment and rotation in patients without forefoot pathology on WBCT.

METHODS

We retrospectively identified 42 feet in 26 patients with sequential WBCT studies less than 12 months apart. Patients with surgery between scans, previous forefoot surgery or hallux rigidus were excluded. Hallux valgus angle (HVA) and intermetatarsal angle (IMA) were measured using digitally reconstructed radiographs. Two methods of calculating metatarsal rotation (metatarsal pronation angle [MPA] and alpha angle) were measured on standardized coronal CT slices. Interobserver agreement and test-retest repeatability were assessed using intraclass correlation coefficients (ICCs). Standard error of measurement (SEM) and minimally detectable change (MDC95) were calculated.

RESULTS

Interobserver agreement was excellent for HVA and IMA (ICC 0.96 and 0.90, respectively) and was good for MPA and alpha angle (ICC 0.81 and 0.80, respectively). There was excellent test-retest repeatability for HVA (ICC=0.90) and good test-retest repeatability for IMA (ICC=0.77). There was excellent test-retest repeatability for MPA (ICC=0.91) and good test-retest repeatability for alpha angle (ICC=0.87). The MDC95 was 4.6 degrees for MPA and 6.1 degrees for alpha angle. Five percent of patients had a difference outside of the MDC95 for the alpha angle, compared with 2% for the MPA.

CONCLUSION

Measurements of first metatarsal alignment and rotation are reliable between assessors and repeatable between sequential WBCTs in patients without forefoot pathology. Subtle differences in patient positioning during image acquisition do not significantly affect measurements, supporting the validity of this method of assessment in longitudinal patient care.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Assessing the Rotation of the First Metatarsal on Computed Tomography Scans: A Systematic Literature Review

BACKGROUND

Hallux valgus is a multiplanar deformity that is often treated on the basis of 2-dimensional (2D) parameters and radiographs. Recurrence rates after surgical correction remain high, and failure to correct pronation of the metatarsal is increasingly stipulated as being part of the problem. Multiple methods of assessing metatarsal pronation have been proposed.

METHODS

We performed a systematic literature review identifying studies that measured metatarsal pronation and torsion on computed tomography (CT) scans. Specific methodology, patient groups, results, and reliability assessments were all reported.

RESULTS

We identified 14 studies that fulfilled the inclusion criteria. Eleven studies measured 2D values on CT scan, and 3 studies used computer-based 3-dimensional (3D) modeling and artificial intelligence systems to help calculate pronation. Metatarsal pronation angle, α angle, sesamoid rotation angle, and measurements for torsion were the most commonly used methods. All angles and measurements were performed as 2D measurements, but the metatarsal pronation angle was also performed with 3D modeling. Reliability and reproducibility of the α angle and metatarsal pronation angle were excellent, despite being performed on studies with small numbers.

CONCLUSION

Multiple methods have been reported to demonstrate first metatarsal pronation on CT, of which the α angle and the metatarsal pronation angle are the most pragmatic and useful in a clinical setting. Further work is needed to further validate the reliability of these measurements in larger series and to identify normal pronation and metatarsal torsion on weightbearing imaging. Further work is required to determine whether addressing pronation reduces recurrence rates and improves outcomes in surgery for hallux valgus.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Prevalence and Predisposing Factors for Recurrence after Hallux Valgus Surgery: A Systematic Review and Meta-Analysis

Recurrence is a frequent and undesirable outcome after hallux valgus (HV) surgery. However, the prevalence of HV recurrence and the pre- and postoperatory factors associated with it have not been adequately studied. This study aimed to quantify the prevalence rate of HV recurrence and to analyze its predisposing factors. MEDLINE and EMBASE databases were systematically searched for observational studies including individuals undergoing HV surgical correction. The random-effects restricted maximum likelihood model was used to estimate the pooled effect size (correlation coefficient (r)). Twenty-three studies were included, yielding a total of 2914 individuals. Pooled prevalence of HV recurrence was 24.86% (95% confidence interval (CI), 19.15 to 30.57, I² = 91.92%, p = 0.00). Preoperative HV angle (HVA) (r = 0.29; 95% CI, 0.14 to 0.43) and preoperative intermetatarsal angle (IMA) (r = 0.13; 95% CI, 0.00 to 0.27) showed a moderate positive relationship with recurrence. Postoperative HVA (r = 0.57; 95% CI, 0.21 to 0.94) and sesamoid position (r = 0.46; 95% CI, 0.31 to 0.60) showed strong relationships with recurrence. In conclusion, preoperative HVA, IMA, and postoperative HVA and sesamoid position are significant risk factors for HV recurrence, and the association of these factors with recurrence is affected by age.

Management of the Tarsometatarsal Joint in the Rotational Correction of Hallux Valgus by the Modified Lapidus Procedure: Intraoperative Technical Tips to Prevent Complications

The modified Lapidus procedure is considered a useful tool for correction of multiplanar deformities in the hallux valgus, including first metatarsal pronation. It offers a greater power of correction compared to most other osteotomies. However, postoperative complications can occur in up to 12% of cases. The aim of this study was to describe intraoperative technical tips in the management of the tarsometatarsal joint during multiplanar correction of severe hallux valgus deformity using the modified Lapidus procedure. It is not the authors' intention to describe a new technique, but to draw attention to intraoperative details in order to prevent complications as nonunion, extension of the first metatarsal and undercorrection of the deformity. Rotational correction of the first metatarsal with adequate bone coaptation of the first metatarsal and the medial cuneiform are the cornerstone for a satisfactory result.Levels of Evidence: Level V, expert opinion.

Symptomatic Medial Bone Excrescence in the Distal Phalanx of the Hallux after the First Metatarsophalangeal Joint Arthrodesis: A Case Report and Radiographic Reviews

Medial bone excrescence at the base of the distal phalanx of the hallux is a common manifestation which is rarely painful. In this case report, we described the first case of the excrescence becoming symptomatic one year after a metatarsophalangeal (MTP) joint arthrodesis of the great toe in a 74-year-old female. The medial bony excrescence which was obscure preoperatively became obvious postoperatively in the anteroposterior foot radiographs. The patient was successfully treated by an excision of the excrescence. In order to clarify the pathology of the excrescence, we reviewed the radiographs with respect to the excrescence before and after hallux surgeries including 97 metatarsal osteotomies and 33 MTP joint arthrodesis. The width of the excrescence measured in the anteroposterior foot radiographs displayed substantial increment one month after the hallux surgeries (osteotomy group: 0.9 ± 0.7 vs. 1.5 ± 0.7 mm, p < 0.01; arthrodesis group: 1.3 ± 0.8 vs. 1.8 ± 1.0 mm, p < 0.01). However, there was no significant difference in the width of the excrescence between one month after surgery and at the most recent follow-up of around 20 months in average after the surgery (osteotomy group: 1.5 ± 0.7 vs. 1.4 ± 0.7 mm, p = 0.62; arthrodesis group: 1.8 ± 1.0 vs. 1.8 ± 0.7 mm, p = 0.37). The present case and our radiographic review suggested that the postoperative medial bony excrescence was not the result of change of position of the preexisting excrescence. The correction of pronation deformity through hallux surgeries could emphasize the medial bony excrescence and cause symptomatic irritation upon shoe contact.

The Assessment of First Metatarsal Rotation in the Normal Adult Population Using Weightbearing Computed Tomography

BACKGROUND

The importance of the rotational profile of the first metatarsal is increasingly recognized in the surgical planning of hallux valgus. However, rotation in the normal population has only been measured in small series. We aimed to identify the normal range of first metatarsal rotation in a large series using weightbearing computed tomography (WBCT).

METHODS

WBCT scans were retrospectively analyzed for 182 normal feet (91 patients). Hallux valgus angle, intermetatarsal angle, anteroposterior/lateral talus-first metatarsal angle, calcaneal pitch, and hindfoot alignment angle were measured using digitally reconstructed radiographs. Patients with abnormal values for any of these measures and those with concomitant pathology, previous surgery, or hallux rigidus were excluded. Final assessment was performed on 126 feet. Metatarsal pronation (MPA) and α angles were measured on standardized coronal computed tomography slices. Pronation was recorded as positive. Intraobserver and interobserver reliability were assessed using intraclass correlation coefficients (ICCs).

RESULTS

Mean MPA was 5.5 ± 5.1 (range, -6 to 25) degrees, and mean α angle was 6.9 ± 5.5 (range, -5 to 22) degrees. When considering the normal range as within 2 standard deviations of the mean, the normal range identified was -5 to 16 degrees for MPA and -4 to 18 degrees for α angle. Interobserver and intraobserver reliability were excellent for both MPA (ICC = 0.80 and 0.97, respectively) and α angle (ICC = 0.83 and 0.95, respectively). There was a moderate positive correlation between MPA and α angle (Pearson coefficient 0.68, P < .001).

CONCLUSION

Metatarsal rotation is variable in normal feet. Normal MPA can be defined as less than 16 degrees, and normal α angle can be defined as less than 18 degrees. Both MPA and α angle are reproducible methods for assessing rotation. Further work is needed to evaluate these angles in patients with deformity and to determine their significance when planning surgical correction of hallux valgus.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Correlation between indirect radiographic parameters of first metatarsal rotation in hallux valgus and values on weight-bearing computed tomography

PURPOSE

To verify if indirect radiographic signs of first metatarsal pronation, determined by the head round sign, correspond to weight-bearing computed tomography (WBCT) measurements.

METHODS

In this case-control retrospective study, we analyzed 26 hallux valgus (HV) feet and 20 controls through conventional radiograph (CR) and WBCT images. Two blinded orthopaedic foot and ankle surgeons performed the measurements. Pronation classification (head roundness), head diameter (HD), traditional HV angles, arthritis, sesamoid positioning, and first metatarsal rotation angle (MRA) (alpha angle) were evaluated. Comparisons were performed by Student's T-test and a multivariate regression was executed. P-values less than 0.05 were considered significant.

RESULTS

Mean values were higher in HV patients than controls when evaluating MRA (11.51 [9.42-13.60] to 4.23 [1.84-6.62], 95%CI), HD (22.35 [21.52-23.18] to 21.01 [20.07-21.96]), and sesamoid rotation angle (SRA) (26.72 [24.09-29.34] to 4.56 [1.63-7.50]). The MRA had a low influence in head roundness classification (R²: 0.15). Changes in the pronation classification were explained chiefly by the sesamoid station (SS) (R²: 0.37), where stations 4 to 7 were found to be strong predictors of roundness classifications 2 and 3.

CONCLUSION

Indirect signs of metatarsal pronation, determined by the head round sign, correlate weakly with the alpha angle measured in WBCT. The presence of arthritis and sesamoids displacement might modify the perception of first head roundness. The influence of MRA in the classification was low, where SS from 4 to 7 was strong predictors of a higher pronation classification.

Outcome of proximal triple derotational metatarsal osteotomy for three-dimensional correction of hallux valgus deformity

PURPOSE

To correct hallux valgus deformities in patients with a greater pronation of the first metatarsal, we designed a novel proximal triple derotational metatarsal osteotomy (PTDMO), which could be used to achieve three-dimensional correction of hallux valgus deformities at the proximal metatarsal level.

METHODS

We prospectively evaluated the radiographic and clinical outcomes of 13 consecutive cases underwent PTDMO between November 2018 and May 2020. The minimum follow-up for inclusion was 12 months. The hallux valgus angle (HVA), first-to-second intermetatarsal angle (IMA), distal metatarsal articular angle (DMAA), relative length of the second metatarsal, and medial sesamoid position on the weight bearing foot anteroposterior radiographs, and the degree of the first metatarsal pronation on forefoot axial radiographs were measured pre-operatively, at six weeks post-operatively, and at the final follow-up. The American Orthopaedic Foot and Ankle Society (AOFAS) score and Foot Ankle Outcome Scores (FAOS) were measured.

RESULTS

In the comparison of pre-operative and final follow-up parameters, HVA, IMA, and DMAA were significantly improved post-operatively (all, P < 0.001). The relative length of the second metatarsal did not differ significantly post-operatively (P = 0.724). The medial sesamoid was significantly reduced (P = 0.01), and the first metatarsal pronation decreased by 10.16° (P = 0.034). Regarding clinical parameters, the AOFAS score and FAOS in all categories significantly improved post-operatively (all, P < 0.001).

CONCLUSION

PTDMO resulted in satisfactory radiographic and clinical outcomes with respect to deformity correction and pain relief, with significant post-operative reduced pronation of the first metatarsal.

A prospective study to compare the operative outcomes of minimally invasive proximal and distal chevron metatarsal osteotomy for moderate-to-severe hallux valgus deformity

PURPOSE

The effectiveness of minimally invasive surgery (MIS)-distal chevron metatarsal osteotomy (DCMO) for the correction of moderate-to-severe hallux valgus deformity is unclear. This study aimed to compare the radiographic and clinical outcomes of our novel MIS-proximal chevron metatarsal osteotomy (PCMO) with those of MIS-DCMO performed during the same timeframe.

METHODS

We prospectively compared the outcomes of patients who underwent MIS-PCMO (n = 20 patients; 22 cases) with those of patients who underwent MIS-DCMO (n = 23 patients; 26 cases) for moderate-to-severe hallux valgus deformity (hallux valgus angle [HVA] ≥ 30° and first-to-second intermetatarsal angle [IMA] ≥ 13°) between June 2017 and January 2019. The minimum follow-up duration for study inclusion was two years. The HVA, IMA, distal metatarsal articular angle (DMAA), relative length of the second metatarsal, medial sesamoid position, and Meary's angle to evaluate the degree of deformity correction and its maintenance were measured pre-operatively and at the final follow-up.

RESULTS

Compared with MIS-DCMO, MIS-PCMO resulted in significantly greater correction of the HVA (P < 0.001) and IMA (P = 0.01), along with Meary's angle improvement (P < 0.001); however, the DMAA worsened (P = 0 .01). Furthermore, a significantly greater change was found in the relative second metatarsal length in the MIS-DCMO group (P = 0.01). No significant between-group differences were noted in the correction of the medial sesamoid position (P = 0.445).

CONCLUSION

Compared with MIS-DCMO, MIS-PCMO can be a better option for correcting moderate-to-severe hallux valgus deformities. However, this technique should be applied carefully when the pre-operative DMAA is already large because the DMAA can become worse post-operatively.

The Rotational Positioning of the Bones in the Medial Column of the Foot: A Weightbearing CT Analysis

BACKGROUND

Malrotation of medial column bones of the foot has been advocated as an important factor in foot conditions such as hallux valgus and progressive collapsing foot deformity. Although stated as a deformity component, variances of normality in the general population are not completely understood. This study intended to describe the rotational profile of all medial column bones using weightbearing computed tomography (WBCT) images in a cohort of patients with different foot and ankle problems.

METHODS

In this retrospective study, 110 feet of 95 consecutive patients that received a WBCT for assessment of different foot and ankle pathologies were included. Measurements were performed by a blinded fellowship-trained orthopedic foot and ankle surgeon. Rotation of the navicular, medial cuneiform, proximal and distal first metatarsal as well as proximal phalanx of the first toe were recorded. Positive values were considered pronation and negative values were considered supination. Rotational profile of each bone/ segment was assessed by ANOVA and comparison between each segment was performed using Wilcoxon Each-Pair analysis. P-values of less than 0.05 were considered significant.

RESULTS

On average, a rotational positioning in pronation (internal rotation) was observed for all medial column bones. The navicular (43.2°, CI 41.1°-45.3°) and the proximal metatarsal (33.9°, CI 31.8°-36.0°) showed the highest mean rotation values. The medial cuneiform presented the lowest mean pronation (6.1°, CI 4.0°-8.3°). Comparison between each bone segment demonstrated statistically significant differences of rotational alignment for the different bones (p<0.0001), with the exception of the distal metatarsal and proximal phalanx, that had similar amounts of pronation. A zig-zag rotational pattern of alignment was observed from proximal to distal, with relative supination/pronation of adjacent medial column bones.

CONCLUSION

The overall rotational profile of medial column bones was found to be in absolute pronation, most pronounced at the navicular and proximal first metatarsal, with significant differences in the amount of pronation when comparing most of the medial column bones. The presented data may be utilized as reference/ baseline values of medial column rotation, supporting future prospective, comparative and controlled studies.Level of Evidence: IV.