Hypermobility of the first ray: a critical review of the literature

Lapidus Bunionectomy

Since 1911, the Lapidus procedure for bunionectomy has evolved from a severity-based indication to an anatomic based system. It addresses the hallux valgus deformity at the anatomic center of rotational and angulation and frontal, transverse, and sagittal plane deformities. It has been shown to be predicable in outcomes and has a low recurrence rate versus other bunion procedures.

Controversial Matters of Minimally Invasive Bunion Repair

New minimally invasive bunion surgery for hallux valgus (HV) has received attention in the last few years. A rapid growth in knowledge and techniques has been seen, with many publications, books, and experienced surgeons worldwide. Several variational advancements have emerged with the most common as a percutaneous subcapital osteotomy first metatarsal with long scaffolding minimally invasive (MI) screw placement. MI techniques are a great advancement in the treatment of all HV severities. Supportive literature has demonstrated that MI can achieve equal to better results compared to traditional open surgery, for metrics such as satisfaction, pain, and time to full recovery.

Midterm outcomes of the modified Lapidus arthrodesis using the Phantom® Intramedullary Nail System for the treatment of hallux valgus

BACKGROUND

Lapidus arthrodesis is one of the most commonly used techniques in the correction of moderate and severe hallux valgus. We analyzed the clinical and radiological outcomes after using the Phantom® Lapidus intramedullary nail to find an effective technique with low complications.

METHODS

We retrospectively analyzed data of 52 patients who underwent a modified Lapidus arthrodesis with an intramedullary nail at our center from November 2019 to September 2022. The mean follow-up period was 27 (range, 18-34) months. Clinical results were evaluated using the visual analog scale (VAS), the European Foot and Ankle Society score (EFAS) and the American Orthopaedic Foot and Ankle Society score (AOFAS); three different radiological measures were analyzed.

RESULTS

The mean AOFAS score increased from 44.8 to 82 points. The mean EFAS score increased from 11.2 to 20.1 points. The mean VAS score decreased by 4.7 points. The mean EFAS Sport score was increased from 9.2 (SD 4.6) to 12.6 (SD 5.4) points. The intermetatarsal angle decreased from 15° to 6.9° and the hallux valgus angle by a mean of 17.9°. The forefoot width reduced from 93.6 to 84.7 mm. All results were statistically significant (p < .001). One case of nonunion was recorded. No implant-related complications were observed.

CONCLUSIONS

This device was effective in correcting moderate to severe hallux valgus, with significant patient satisfaction. Its complication rate was not higher than that of other fixation devices. Correct compression of the arthrodesis, absence of extraosseous material, and multidirectional stability are important qualities of this implant for the correct treatment of this pathology.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

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.

What Do Patients Report Regarding Their Real-World Function Following Concurrent Arthrodesis of the First Tarsometatarsal and First Metatarsophalangeal Joints

First metatarsal phalangeal joint and the first Tarsometatarsal arthrodesis have both been used for deformity correction and treatment of pain and arthritis. Concomitant arthrodesis of the first metatarsophalangeal and first tarsometatarsal joints (Double First Ray Arthrodesis) has rarely been described. We surveyed 29 patients who underwent double first-ray arthrodesis for primary or revision correction of hallux valgus. A custom questionnaire was used to assess their activities of daily living and sports activity at a mean follow-up of 19.6 months (median 18.4 months). Secondary endpoints were return to activity, deformity correction, and arthrodesis healing rate. The primary outcomes showed an excellent return to activities of daily living with 96.6% of patients capable of walking as much as they liked after surgery at a normal pace. About 96.6% reported they felt that their surgery was successful, they had no pain, and the loss of motion at the joint fusion sites did not affect their ability to perform daily activities. Protected walking in a fracture boot was initiated at a mean (SD) of 9.8 (9.9) days. Return to an athletic shoe occurred at a mean (SD) of 44.2 (11.7) days. Full unrestricted activity was at a mean (SD) of 105.2 (19.3) days with 65% of the patient group reporting that their recovery was easier than expected. There was 1 nonunion and no other complications. This data set supports the hypothesis that patients undergoing double first-ray arthrodesis can return to activities of daily living and sports with and low complication rate.

The Lapidus Bunionectomy Revolution: Current Concepts and Considerations

Hallux valgus is a common foot deformity in which many surgical techniques have been introduced. Originally, Paul Lapidus detailed a midfoot arthrodesis technique to address the deformity and medial column instability that served as the foundation for the modified Lapidus bunionectomy. The appreciation of the multiplanar nature of hallux valgus deformity continues to evolve and helps to guide the investigation of the ideal surgical correction to yield more predictable results and reduced complications. Various fixation constructs have been used over the years for the Lapidus bunionectomy without a clear superior fixation technique, and literature supports early weight-bearing with each.

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.

Modified Endoscopic Distal Soft Tissue Procedure (mEDSTP) and Arthroscopic Lapidus Arthrodesis for Correction of Severe Hallux Valgus

Hallux valgus is one of the most common forefoot deformities faced by foot and ankle surgeons. Symptomatic deformity usually needs surgical correction. Endoscopic techniques of hallux valgus correction have been reported that are based on the same principle of the classic distal soft tissue procedure. Recently, the technique has been modified to include reconstruction of the medial metatarsosesamoid ligament and augmentation of the intermetatarsal ligament. In severe deformity or the presence of hypermobility or painful degeneration of the first tarsometatarsal joint, Lapidus arthrodesis of the joint is indicated. Arthroscopic Lapidus arthrodesis has been reported to reduce the complications associated with open procedure, including first metatarsal shortening, metatarsal elevatus, and nonunion. In this technical note, the technical details of a combined modified endoscopic distal soft tissue procedure and arthroscopic Lapidus arthrodesis is described. This is a minimally invasive approach for correction of severe hallux valgus deformity, especially that associated with ligamentous laxity.

Evaluation of first ray instability using the double dorsiflexion test: A prospective observational case-controlled study

BACKGROUND

First-Ray (FR) stability allows for foot propulsion in-stance, taking 60% weight. First-ray instability (FRI) is associated with middle column overload, synovitis, deformity and osteoarthritis. Clinical detection can still be challenging. We propose to develop a clinical test that helps identify FRI using two simple manual manoeuvres.

METHODS

10 patients with unilateral FRI were recruited. Unaffected contralateral feet were used as controls. Stringent exclusion criteria were applied including hallux MTP pain, laxity, inflammatory arthropathy and collagen disorders. A Klauemeter directly measured the sagittal plane dorsal first metatarsal head translation of affected vs unaffected feet. Maximum passive proximal phalanx 1st MTP joint dorsiflexion was measured using a video capture and Tracker motion software analysis with and without applying a dorsal force at the 1st metatarsal head using a Newton meter. Proximal phalanx motion was compared in affected vs unaffected feet with and without dorsal metatarsal head force application and compared to direct measurements using the Klaumeter. P value of < 0.05 was considered significant.

RESULTS

FRI feet had dorsal translation greater than 8 mm (median, 11.94; interquartile range [IQR], 10.23-13.81) vs 1.77 for unaffected control feet was (median, 1.77; interquartile range [IQR], 1.23-2.96) using the Klauemeter. The percentage reduction in 1st MTP joint dorsiflexion ROM when applying the double dorsiflexion test FRI (mean reduction of 67.98%) when compared to control feet (mean reduction of 28.44%)(P < 0.01). Receiver operating characteristic (ROC) analysis showed that a 50% reduction in dorsiflexion ROM of 1st MTPJ when performing the double dorsiflexion test achieved a specificity of 100% and sensitivity of 90% (AUC =0.990, 95%CI [0.958-1.000], P > 0.0001).

CONCLUSION

The double dorsiflexion (DDF) is easy to perform with two relatively simple manual manoeuvres that avoids the need for complex instrumented and radiation-based assessment. Greater than 50% decrease in proximal phalanx motion has an over 90% sensitivity in identifying feet with FRI.

LEVEL OF EVIDENCE

This was a prospective case-controlled study of consecutive cases of a level II evidence.

Correlation Analysis Between Clinical Hypermobility Measurement and Radiographic Parameters of the Hallux Valgus Deformity

The finding of "hypermobility" has conventionally been considered as a dichotomous categorical variable in both clinical practice and in the literature. In other words, it is defined as being either "present" or "absent" in patients with hallux valgus. Yet it might be far more likely that this represents a continuous variable described by a bell-shaped distribution. Therefore the objective of this investigation was to consider hypermobility as a continuous variable, and to compare the sagittal plane first ray motion to radiographic parameters commonly used in the evaluation of the hallux valgus deformity by means of correlation analyses. The radiographs and measurements of 86 feet were included and measurement of sagittal plane first ray motion was performed with the validated Klaue device. No statistically significant correlation was observed between the total first ray motion with the first intermetatarsal angle (Pearson correlation coefficient 0.106; p = .333), hallux valgus angle (Pearson correlation coefficient -0.106; p = .330), nor sesamoid position (Pearson correlation coefficient 0.155; p = .157). The results of this investigation uniquely consider measurement of hypermobility as a continuous variable, and find no correlation between first ray sagittal plane motion and radiographic parameters associated with the hallux valgus deformity. These results might indicate that although the concept of hypermobility has traditionally been coupled with presentation of the hallux valgus deformity, this might simply represent the result of a historical confirmation bias.

First Tarsometatarsal Joint Fusion for Hallux Valgus Deformity: A Retrospective Comparison of Two Fixation Constructs Regarding Initial Maintenance of Correction and Complications: Traditional Crossing Screw Fixation Versus Dorsomedial Locking Plate and Intercuneiform Compression Screw

Various fixation constructs exist to address hallux valgus when performing a first tarsometatarsal joint arthrodesis. The goal of this present study is to compare complication rates, and degree and maintenance of angular correction between a dorsomedial locking plate with intercuneiform compression screw construct versus traditional crossing solid screw fixation construct. The plate plus intercuneiform compression screw construct fixation utilized a combined sagittal saw and curette method of joint preparation while the crossed screw fixation group utilized a curette and bur technique. A retrospective review was conducted of consecutive patients who underwent a midfoot fusion using either constructs. Sixty four total feet in 56 patients were enrolled in the study. Twenty four consecutive patients (32 feet) who underwent a midfoot arthrodesis using the locking plate and intercuneiform fixation were fully fused (100%) by 10 weeks postoperatively, with no incidents of nonunion and one deep vein thrombosis event. Thirty two consecutive patients (32 feet) who underwent midfoot arthrodesis with crossing screw fixation had 2 nonunion events, one that was asymptomatic and the other that required a revision midfoot fusion. There was a statistically significant improvement from the pre-operative intermetatarsal angle, hallux abductus angle compared to the 10 week and 1 year radiographs (p < .05) for the entire cohort for both fixation constructs. There was a statistically significant increase in American College of Foot and Ankle Surgery first ray scores from pre-op to 1 year follow-up for both fixation constructs. Overall, the dorsomedial locking plate plus intercuneiform compression screw fixation construct better maintains Intermetatarsal angle (IMA) correction at midterm follow-up compared to the traditional crossing screw construct. Both cohorts overall demonstrate similar fusion rates at 10 weeks, nonunion events, incidences of broken hardware, hardware removal, deep vein thrombosis, neuritis at 1 year postoperatively, and hallux varus.

An Operational Definition of First Ray Hypermobility

BACKGROUND

The first ray (metatarsocuneiform) behaves as a load-bearing strut in supporting weight. Due to its functional importance, stress-testing techniques are used to assess the stability of the first ray and objectify evidence of hypermobility. The test and measurement of first ray hypermobility (FRH) is of interest to clinicians and researchers. The condition itself, however, has proven elusive to diagnose. This article defines FRH for the purpose of improving the consistency by which the diagnosis is made. Currently, the lack of a consensus definition prevents research from determining the incidence rates and prevalence of FRH, a commonly reported medical condition.

THE DEFINITION

Symptomatic FRH presents as dorsal displacement that measures greater than 8 mm, accompanied with signs and symptoms consistent with loading insufficiency of the first ray. The operational definition is objective and if adopted across health care professions, the criterion could become the standard for identifying FRH in patients and research participants.

LEVEL OF EVIDENCE

Level V, expert opinion.

Addressing Transverse Plane Instability in the Modified Lapidus Arthrodesis: A Comparative Study of Screw Versus Suture and Button Fixation Device Technique

The Lapidus arthrodesis is a powerful procedure for the correction of hallux valgus with metatarsus primus varus. Yet, first ray instability may persist despite correction of the primary deformity with 2 crossed screw fixation. A third screw is often utilized as the additional point of fixation for noteworthy residual transverse plane motion, but it is not without potential complications. The suture and button fixation device may be an appropriate alternative to the third screw construct. This retrospective cohort study identified clinical / radiographic outcomes and complication rates following a third point of fixation with either a screw or suture and button fixation device in patients undergoing a modified Lapidus arthrodesis. One surgeon performed all of the Lapidus procedure with a third screw while the other surgeon performed all with a suture and button fixation device. Of 136 consecutive patients who underwent a modified Lapidus arthrodesis, 83 (61%) patients required a third point of fixation for satisfactory stabilization of the first ray. Surgical technique was similar between the 2 surgeons; however, one utilized the suture and button fixation device method (n = 36), while the other used a third screw for fixation (n = 47). Many of the clinical outcomes, radiographic results, and the union rate were similar between the 2 methods. Nineteen (40%) complications occurred in the third screw group compared to 6 (17%) in the suture and button fixation device group. However, the third screw group demonstrated 100% maintenance of deformity correction at 1 year versus 95% in the suture and button fixation device group. Although fixation with a suture and button fixation device was associated with fewer complications, a larger study is necessary to determine if these variations are statistically significant.

Arthroscopic Lapidus Arthrodesis of the First Tarsometatarsal Joint for Treatment of Hallux Valgus Deformity of the Foot

Hypermobility of the first tarsometatarsal joint can associate with different clinical problems, e.g., hallux valgus, hallux elevatus, hallux rigidus, and transverse metatarsalgia or arthritis of the second metarsocuneiform joint. The first tarsometatarsal joint may also contribute to other foot deformities involving the medial foot column. Osteoarthritis of this joint is one of the causes of medial foot pain. Arthrodesis of the first tarsometatarsal joint (modified Lapidus procedure) is indicated for these conditions, which are resistant to conservative treatment. Lapidus arthrodesis has several potential complications, including first metatarsal shortening, metatarsal elevates, and nonunion. Arthroscopic Lapdius arthrodesis has been reported to reduce these complications. In this Technical Note, the technical details of arthroscopic Lapidus arthrodesis is described.

Descriptive Quantitative Analysis of First Metatarsal Sagittal Plane Motion

Evaluation of the sagittal plane motion of the first ray is a commonly accepted physical examination technique performed during the assessment and treatment of the hallux valgus deformity. Excessive or abnormal motion in this location, termed "hypermobility," has also traditionally been strongly associated with surgical decision-making and serves as a widely accepted indication for performance of the first metatarsal-medial cuneiform arthrodesis procedure. The objective of this investigation was to perform an analysis of first ray sagittal plane motion from a large population in order to determine the descriptive quantitative characteristics of the data set. First metatarsal sagittal plane motion was measured from a group of 149 subjects (298 feet) with a Klaue device. The mean total first metatarsal sagittal plane motion was 9.37 ± 2.39 mm (3.97-18.76). The data set was found to demonstrate many of the characteristics of a normally distributed population based on the histogram distribution, skewness (0.651), and kurtosis (0.761). No difference was observed between measurement of total sagittal plane motion between right and left feet (9.13 ± 2.37 mm vs 9.61 ± 2.40 mm; p = .081), nor between male and female subjects (9.29 ± 2.27 mm vs 9.58 ± 2.70 mm; p = .352). No substantial correlation was observed between total sagittal plane motion and subject age (Pearson correlation -0.053; p = .522). Results indicate that first ray sagittal plane motion might be best considered as a continuous variable as opposed to categorical variable, and might help objectify the difference between "normal" and "abnormal" motion.

The Failed Deltoid Ligament in the Valgus Misaligned Ankle-How to Treat?

This article deals with the treatment of a chronically failed deltoid ligament complex in the valgus misaligned ankle. This is a challenging task in every orthopedic foot and ankle surgery. Before embarking on any surgery that relates to the deltoid ligament complex, it is mandatory to analyze any underlying cause that could promote the impairment. Once this is done, it might be of value in considering anatomic reconstructions. The article provides an anatomic reconstruction technique, which should help address the problem.

The Role of Weightbearing Computed Tomography Scan in Hallux Valgus

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.

Hypermobility of the First Ray: the Cinderella of the measurements conventionally assessed for correction of Hallux Valgus

Background and aim of the work:

hypermobility of the first ray (FRH) began to be considered as a pathological entity from Morton’s studies and was associated as a primary cause of hallux valgus (HV). Currently, this relationship is in discussion, and various authors consider FRH as a consequence of the deformity. The purpose of this narrative review is to summarise the most influential publications relating to First Ray Mobility (FRM) to increase knowledge and promote its conventional assessment during clinical practice.

Methods:

papers of the last century were selected to obtain a homogeneous and up-to-date overview of I-MTCJ mobility and HV, as well as their relationship and management.

Results:

in recent years, FRH was studied from a biomechanical and pathophysiologic point of view. There is still not enough data regarding the aetiology of FRM. The higher rate of instability found in HV lacks an explanation of which is the cause and which is the effect. However, the Lapidus arthrodesis is still a valid method in cases of FRH and HV, even if is not rigorously indicated to treat both. When approaching FRH, radiographic or clinical findings are mandatory for the right diagnosis.

Conclusions:

FRM is an important factor that must be considered in routine clinical practice and prior and post HV surgery, as much as the conventional parameters assessed. Surgeons should consider performing I-MTCJ arthrodesis only if strictly necessary, also paying attention to soft tissue balancing. Improving the measurement of FRH could be useful to determine if it is a cause or effect of the HV deformity. (www.actabiomedica.it)

The Lateral Column

Lower extremity biomechanics is the cornerstone of podiatric medicine and surgery. The foot and ankle act as the interface between the ground and proximal segments, mediating internal and external moments Although the medial longitudinal arch has been widely researched, the details of the lateral longitudinal arch are less extensively delineated. The purpose of this review is to analyze the biomechanics of the lateral column as it relates to lower extremity biomechanics and function.

Dynamic First Tarsometatarsal Instability During Gait Evaluated by Pedobarographic Examination in Patients With Hallux Valgus

BACKGROUND

This study aimed to investigate the pedobarographic characteristics of tarsometatarsal instability and to identify factors associated with pedobarographic first tarsometatarsal instability in patients with hallux valgus.

METHODS

Fifty-seven patients (mean age, 59.7 years; standard deviation, 11.4 years; 6 men and 51 women) with a hallux valgus angle (HVA) greater than 15 degrees were included. All patients underwent a pedobarographic examination along with weightbearing anteroposterior (AP) and lateral foot radiography. Radiographic measurements were compared between the 2 groups with and without pedobarographic first tarsometatarsal instability. The association between the radiographic and pedobarographic parameters of the first tarsometatarsal instability was analyzed using the chi-square test. Binary logistic regression analysis was performed to identify significant factors affecting pedobarographic first tarsometatarsal instability.

RESULTS

The HVA (P < .001), intermetatarsal angle (P = .001), and AP talo-first metatarsal angle were significantly different between the pedobarographically stable and unstable tarsometatarsal groups. There was no significant association between radiographic and pedobarographic instability of the first tarsometatarsal joint (P = .924). The HVA was found to be the only significant factor affecting pedobarographic tarsometatarsal joint instability (P = .001).

CONCLUSION

The pedobarographic examination has possible clinical utility in evaluating first tarsometatarsal joint instability in patients with hallux valgus. Patients with a greater HVA should be assessed for the presence of first tarsometatarsal instability, and the necessity of the Lapidus procedure should be considered.

LEVEL OF EVIDENCE

Level III, comparative study.

Measurement of Dorsal First Ray Mobility: A Topical Historical Review and Commentary

Despite evidence that instability of the first ray (first metatarsal and medial cuneiform) alters the loading mechanics of the foot, surprisingly few studies have linked the condition with disorders of the foot. A factor limiting this research is the difficulty associated with measuring first ray mobility (FRM). To quantify dorsal FRM, clinicians and researchers have devised a variety of methods that impose a dorsally directed load, and record displacement. The methods include manual examination, radiographs, mechanical devices, and handheld rulers. Since different methods yield different results; each of these methods is worthy of scrutiny. This article reviews the methods used to quantify dorsal FRM and offers commentary on how the testing procedures could be standardized. The measurement of dorsal FRM informs surgical decisions, orthotic prescriptions, and research design strategies mostly as it pertains to the identification and treatment of first ray hypermobility. This review found sufficient support to recommend continued use of radiographs and mechanical devices for quantifying dorsal displacement, whereas measurements acquired with handheld rulers are prone to the same subjective error attributed to manual examination procedures. Since measures made with radiographs and existing mechanical devices have their own drawbacks, the commentary recommends ideas for standardizing the testing procedure and calls for the development of a next-generation device to measure dorsal FRM. This future device could be modeled after arthrometers that exist and are used to quantify stability at the knee and ankle. Level of Evidence: Level V, expert opinion.

Triplane Hallux Abducto Valgus Classification

One of the most common procedures performed in the foot and ankle is correction of hallux abducto valgus deformity or "bunion surgery." Most foot and ankle surgeons recognize the challenges associated with defining each patient's individual deformity and selecting the optimal procedure for the best long-term results. Using current 2-dimensional algorithms that focus on the severity of the transverse plane deformity, surgical outcomes have varied. In the past 10 years, high recurrence and complication rates for popular procedures have been reported. In the same period, the reported data have elucidated an evolving anatomic understanding of the bunion deformity, with an expansion to 3 dimensions, including the frontal/coronal plane. We present a new classification and approach for the evaluation and procedure selection for bunion surgery. We hope this conceptual treatise on hallux abducto valgus based on clinical consensus and current data will stimulate academic discussion and further research. This anatomic classification is based on the 3-dimensional anatomy of the first ray.

Is it still current to talk about first ray hypermobility?

Since the time of D. Morton in clinical evaluation we talked about the concept of hypermobility as a cause of diseases such as hallux valgus. To date, this concept has been deepened in order to better understand the pathological mechanisms that create deformity, in order to identify the most appropriate prevention and correction procedures. Physics introduced the concept of stiffness, a property that also belongs to the podalic structures. Changing the terminology is difficult, but the knowledge of biomechanics requires the elimination of the term hypermobility because it resultsinconsistent with the physics applied to the foot, in favor of the terms stiffness and compliance. These clarifications make it possible to us to deepen even more specific and timely therapeutic choices, thus reducing the risk of iatrogenic complications which follows interventions on the first ray. (www.actabiomedica.it)

Outcome of the modified Lapidus procedure for hallux valgus deformity during the first year following surgery: A prospective clinical and gait analysis study

BACKGROUND

The modified Lapidus procedure is a surgical option to treat moderate to severe hallux valgus deformity with good radio-clinical outcome. However, comprehensive biomechanical outcome evaluation of this surgery at mid-term follow-up is missing. This study assesses and compares the radio-clinical and gait outcome at 6 and 12 months following modified Lapidus procedure.

METHOD

Ten consecutive female patients with moderate to severe hallux valgus who underwent modified Lapidus procedure participated in the study. Comprehensive gait assessment was performed preoperatively, at 6 and 12 months postoperatively. Gait parameters including spatiotemporal, kinematics and plantar pressure were analyzed using pressure insoles and 3-dimensional inertial sensors. Outcome was evaluated using two clinical questionnaires, i.e. the American Orthopaedic Foot and Ankle Score and the Foot and Ankle Ability Measure, and X-rays.

FINDINGS

Three spatiotemporal, two kinematics, and seven plantar pressure parameters significantly improved between 6 months and 12 months postoperatively. Significant improvement in radiological and clinical outcome was reported at 6 and 12 months. The Foot and Ankle Ability Measure showed non-significant improvement at 12 months.

INTERPRETATION

The outcome of this study is consistent with the previously reported good clinical and radiological results at one year following Lapidus for moderate to severe hallux valgus. Twelve gait parameters demonstrated that outcome improves from 6 months to 12 months postoperative with room for further improvement at long term. The gait outcome in this study confirms the longer rehabilitation period following modified Lapidus procedure. Studies with a larger sample size are required to confirm these findings.

Pilot Study of a 3-Dimensional Method for Analysis of Pronation of the First Metatarsal of Hallux Valgus Patients

BACKGROUND:

The current work sought to quantify pronation of the first metatarsal relative to the second metatarsal and of the proximal phalanx of the great toe relative to the first metatarsal.

METHODS:

Three-dimensional models were reconstructed from weightbearing computed tomography (CT) images (10 hallux valgus, 10 normal). The orientations of bones related to hallux valgus (HV) (ie, the phalanx, first and second metatarsals) were determined from coordinate systems established by selecting landmarks. After determining the hallux valgus and intermetatarsal angles, additional calculations geometrically determined the 3-dimensional (3D) angles using the aeronautical system of yaw-pitch-roll. The 3D geometrically determined angles were compared to the conventional plain radiographic angles.

RESULTS:

HV measurements taken with CT and 3D computer-aided design (3DCAD) geometric methods were the same as measurements taken from plain radiographs (P > .05). The average pronation of the first metatarsal relative to the second metatarsal was 8.2 degrees greater in the hallux valgus group (27.3 degrees) than in the normal group (19.1 degrees) (P = .044). A regression analysis of pronation vs intermetatarsal angle (IMA) was not found to be significant. There was also no correlation between pronation of the great toe and first metatarsal in the HV group.

CONCLUSIONS:

The pronation angle of the first metatarsal relative to the second metatarsal between normal and hallux valgus patients was larger in HV patients but was not well correlated with the IMA.

CLINICAL RELEVANCE:

The findings of this study indicate that pronation may need to be considered in the operative correction of hallux valgus for restoration of normal anatomy.

Static Range of Motion of the First Metatarsal in the Sagittal and Frontal Planes

The first metatarsal and medial cuneiform form an important functional unit in the foot, called “first ray”. The first ray normal range of motion (ROM) is difficult to quantify due to the number of joints that are involved. Several methods have previously been proposed. Controversy exists related to normal movement of the first ray frontal plane accompanying that in the sagittal plane. The objective of this study was to investigate the ROM of the first ray in the sagittal and frontal planes in normal feet. Anterior-posterior radiographs were done of the feet of 40 healthy participants with the first ray in a neutral position, maximally dorsiflexed and maximally plantarflexed. They were digitalized and the distance between the tibial malleolus and the intersesamoid crest in the three positions mentioned was measured. The rotation of the first ray in these three positions was measured. A polynomic function that fits a curve describing the movement observed in the first ray was obtained using the least squares method. ROM of the first ray in the sagittal plane was 6.47 (SD 2.59) mm of dorsiflexion and 6.12 (SD 2.55) mm of plantarflexion. ROM in the frontal plane was 2.69 (SD 4.03) degrees of inversion during the dorsiflexion and 2.97 (SD 2.72) degrees during the plantarflexion. A second-degree equation was obtained, which represents the movement of the first ray. Passive dorsiflexion and plantarflexion of the first ray were accompanied by movements in the frontal plane: 0.45 degrees of movement were produced in the frontal plane for each millimeter of displacement in the sagittal plane. These findings might be useful for the future design of instruments for clinically quantifying first ray mobility.

Can the Syndesmosis Procedure Prevent Metatarsus Primus Varus and Hallux Valgus Deformity Recurrence? A 5-Year Prospective Study

One of the main objectives of hallux valgus surgery is correction of the metatarsus primus varus deformity by osteotomy, arthrodesis, or soft tissue correction. The syndesmosis procedure uses intermetatarsal cerclage sutures to realign the first metatarsal and also induces a syndesmotic bonding between the first and second metatarsals to prevent metatarsus primus varus deformity recurrence. The purpose of the present study was to demonstrate radiologic evidence of the effectiveness of the syndesmosis concept and to identify the incidence and nature of deformity recurrence. A total of 55 feet from 60 consecutive procedures were followed regularly at 6 fixed points for 5 years. The radiologic inclusion criterion was a first intermetatarsal angle >9° or metatarsophalangeal angle >20°. The initial postoperative radiographs showed significant correction of the intermetatarsal angle from a preoperative average of 14.5° to 4.3° (p < .0001). It had increased to 7.0° during the first 6 postoperative months but remained within the normal upper limit of 9° and exhibited no further significant changes for the subsequent 4.5 years (p = .0792). Hallux valgus deformity correction also correlated with metatarsus primus varus deformity correction. Three (5%) second metatarsal stress fractures occurred, and all recovered uneventfully. In conclusion, we have report the findings from a detailed medium long-term follow-up study showing, to the best of our knowledge, for the first time that metatarsus primus varus and hallux valgus deformities can be effectively corrected and maintained using a specific surgical technique. Also included are 6 relevant radiographs and photographs of the included and excluded feet in the online Supplementary Material for reference.

Mobility of the First Ray in Patients With or Without Hallux Valgus Deformity: Systematic Review and Meta-Analysis

The hypermobility theory of the first ray is the reason for the popularization of procedures such as the modified Lapidus procedure involving arthrodesis of the first tarsal-metatarsal joint for correction of hallux valgus deformity. Although many studies have involved motion of the first ray in hallux valgus patients, the presence and clinical significance of hypermobility in the first ray remains controversial. We performed a systematic review and meta-analysis to evaluate the difference in the first ray range of motion between patients with or without hallux valgus deformity. The databases used for the present review included Ovid EMBASE, Ovid MEDLINE, CINAHL, and the Cochrane Database. We searched for comparative studies that had evaluated the motion of the first ray in patients with or without hallux valgus. After screening for inclusion and exclusion criteria, we identified 3 studies that were relevant to our study question. All 3 studies showed more first ray motion in the hallux valgus group. Our quantitative synthesis showed a mean difference in the range of motion of the first ray of 3.62 mm (95% confidence interval 2.26 to 4.98) between those with and without hallux valgus deformity. Thus, we found statistically significantly increased first ray motion in patients with hallux valgus deformity compared with those without hallux valgus deformity. However, the clinical significance of this small amount of increased sagittal plane motion as a response to or a cause of hallux valgus remains unanswered.

Treatment of Progressive First Metatarsophalangeal Hallux Valgus Deformity: A Biomechanically Based Muscle-Strengthening Approach

Synopsis Hallux valgus is a progressive deformity of the first metatarsophalangeal joint that changes the anatomy and biomechanics of the foot. To date, surgery is the only treatment to correct this deformity, though the recurrence rate is as high as 15%. This clinical commentary provides instruction in a strengthening approach for treatment of hallux valgus deformity, by addressing the moment actions of 5 muscles identified as having the ability to counter the hallux valgus process. Unlike surgery, muscle strengthening does not correct the deformity, but, instead, reduces the pain and associated gait impairments that affect the mobility of people who live with the disorder. This review is organized in 4 parts. Part 1 defines the terms of foot motion and posture. Part 2 details the anatomy and biomechanics, and describes how the foot is changed with deformity. Part 3 details the muscles targeted for strengthening; the intrinsics being the abductor hallucis, adductor hallucis, and the flexor hallucis brevis; the extrinsics being the tibialis posterior and fibularis longus. Part 4 instructs the exercise and reviews the related literature. Instructions are given for the short-foot, the toe-spread-out, and the heel-raise exercises. The routine may be performed by almost anyone at home and may be adopted into physical therapist practice, with intent to strengthen the foot muscles as an adjunct to almost any protocol of care, but especially for the treatment of hallux valgus deformity. J Orthop Sports Phys Ther 2016;46(7):596-605. Epub 6 Jun 2016. doi:10.2519/jospt.2016.6704.

Comparison of dorsal and dorsomedial displacement in evaluation of first ray hypermobility in feet with and without hallux valgus

BACKGROUND

Hypermobility of the first ray, a probable primary cause of hallux valgus, has traditionally been evaluated in the dorsal direction only although the first tarso-metatarsal joint allows movement in a dorso-medial direction.

MATERIALS AND METHODS

600 feet, divided according to the presence or absence of hallux valgus, were evaluated for both dorsal and dorso-medial displacement using a Klaue device.

RESULTS

In the control group, the mean first ray displacement was 7.2mm (4.2-11.3) in the dorsal direction (sagittal plane) and 8.3mm (4.0-12.6) in the 45° dorso-medial direction. In the hallux valgus group, the mean first ray mobility was 9.8mm (5.2-14.1) in the dorsal direction compared to a mean of 11.0mm (5.9-16.2) in the 45° dorso-medial direction.

CONCLUSION

It is a paradox that hypermobility of the first ray is measured in only a dorsal (vertical) direction whereas a hallux valgus angle and an intermetatarsal angle are only measured in a transverse plane. Furthermore, the weightbearing foot pronates during gait and the first metatarsal is displaced in a dorsomedial direction rather than a pure dorsal direction. It is suggested that measurement hypermobility of the first ray at a 45° dorso-medial direction is more appropriate.

Mobility of the first metatarsal-cuneiform joint in patients with and without hallux valgus: in vivo three-dimensional analysis using computerized tomography scan

Background

Hallux valgus (HV) deformity is closely correlated to the hypermobility of the first metatarsal-cuneiform joint, but adequate understanding of the three-dimentional (3D) mobility of this joint in normal or HV feet is lacking. This study was conducted to investigate the mobility of the first metatarsal-cuneiform joint in multiple planes during body weight-bearing conditions for both normal and HV patients.

Methods

A total of 10 female volunteers (20 feet) and 10 female HV patients (20 feet) participated in this study. Using a custom-made foot-loading device, computerized tomography (CT) scans of each pair of feet were taken under both unloaded and body weight-bearing conditions. 3D models were reconstructed for the first metatarsal and the medial cuneiform. Rotational and translational motions of the first metatarsal-cuneiform joint in multiple planes from unloaded to loaded conditions were quantitatively evaluated by reverse-engineering software.

Results

During body weight-bearing conditions, the first metatarsal-cuneiform joint in HV feet dorsiflexed at an average of 2.91° (standard deviation, SD 1.71) versus 1.18° (SD 0.47) in controls (t = 4.158, P = 0.001); supinated 2.17° (SD 2.28) versus 0.98° (SD 0.81) in controls (t = 2.080, P = 0.045); and internally rotated 2.65° (SD 2.22) versus 0.96° (SD 0.57) in controls (t = 3.114, P = 0.006). Moreover, the joint in HV feet widened significantly compared with the controls (t = 2.256, P = 0.030) and tended to translate more in the dorsal-plantar direction (t = 1.928, P = 0.063); the translation in the medial-lateral direction was not significantly different between the two groups.

Conclusions

During weight-loading process, the first metatarsal-cuneiform joint turns dorsiflexed, supinated, and internally rotated. For HV feet, hypermobility of the first metatarsal-cuneiform joint can be observed in multiple planes. This study promotes further understanding of the physiological and pathological mobility of the first metatarsal-cuneiform joint.

Effects of the lapidus arthrodesis and chevron bunionectomy on plantar forefoot pressures

Hallux valgus with or without first ray insufficiency has been strongly implicated as a contributing factor in lesser metatarsal overload. The principle goals of a bunionectomy are to relieve the pain, correct the deformity, and restore first metatarsophalangeal joint congruity. Until now, little evidence has been available to assess the effects of bunionectomy procedures on forefoot pressure. The primary aim of the present prospective study was to evaluate the preoperative and postoperative plantar pressures after 2 specific bunionectomies: the chevron bunionectomy and Lapidus arthrodesis. A total of 68 subjects, 34 in each group, were included for radiographic and pedographic evaluation. Both procedures demonstrated radiographic improvements in the mean intermetatarsal and hallux abductus angles. The mean hallux plantar pressure decreased significantly in both procedure groups (p < .001). However, Lapidus group exhibited an increase in the mean fifth metatarsal head plantar pressure (p = .008) and pressure under the fifth metatarsal as a percentage of the total forefoot pressure (p = .01). Furthermore, the pressure under the second metatarsal as a percentage of the total forefoot pressure decreased significantly (p = .01). This study suggests that the Lapidus arthrodesis and chevron bunionectomy both provide correction for hallux valgus deformity, but when comparing forefoot load sharing pressures, the Lapidus arthrodesis appeared to have greater influence on the load sharing distribution of forefoot pressure than did the bunionectomy employing the chevron osteotomy.

Clarification of the anatomic definition of the bunion deformity

Evolution of the terminology applied to the bunion deformity has progressed in parallel with our changing understanding of the deformity itself. Along this path of progression have been multiple terms, sometimes with multiple meanings. Hallux valgus and metatarsus primus varus are 2 of the most common terms for the deformity. Although commonly used, these descriptors can have multiple meanings, and inconsistencies in interpretation can lead to confusion. We propose a more detailed terminology to provide a more accurate description of the entire bunion deformity in 3 planes and for both the hallux and the metatarsal component of the deformity. The term we propose is hallux abducto valgus with metatarsus primus adducto valgus. An accurate understanding of the multiplanar position of the deformed foot is important for planning deformity correction. The descriptors in the terminology proposed will keep in the forefront the aspects of correction required for the first ray and hallux to be returned to an anatomically correct position.

First metatarsophalangeal joint motion in Homo sapiens: theoretical association of two-axis kinematics and specific morphometrics

BACKGROUND

The metatarsal head and proximal phalanx exhibit considerable asymmetry in their shape and geometry, but there is little documentation in the literature regarding the prevalence of structural characteristics that occur in a given population. Although there is a considerable volume of in vivo and in vitro experiments demonstrating first metatarsal inversion around its longitudinal axis with dorsiflexion, little is known regarding the applicability of specific morphometrics to these motions.

METHODS

Nine distinctive osseous characteristics in the metatarsal head and phalanx were selected based on their location, geometry, and perceived functional relationship to previous studies describing metatarsal motion as inversion with dorsiflexion. The prevalences of the chosen characteristics were determined in a cohort of 21 randomly selected skeletal specimens, 19 of which were provided by the anatomical preparation office at the University of California, San Diego, and two of which were in the possession of one of us (M.D.).

RESULTS

The frequency of occurrence of each selected morphological characteristic in this sample and the relevant summary statistics confirm a strong association between the selected features and a conceptual two-axis kinematic model of the metatarsophalangeal joint.

CONCLUSIONS

The selected morphometrics are consistent with inversion of the metatarsal around its longitudinal axis as it dorsiflexes.

Hypermobility of the first ray in patients with planovalgus feet and tarsometatarsal osteoarthritis

BACKGROUND

Hypermobility in the foot is a common observation but difficult to quantify. Primary tarsometatarsal arthritis is less common and its aetiology uncertain. This study introduces a novel means of clinical measurement for range of motion of the medial column and investigates the association between hypermobility, planovalgus foot shape and tarsometatarsal arthritis.

METHOD

32 planovalgus feet with symptomatic tarsometatarsal arthritis were compared with 36 controls. Radiographic angular measurements and arthritic grade were recorded from standing radiographs. Medial column flexion and extension was measured clinically using a validated electronic goniometer.

RESULTS

There was a significant difference in medial column range of motion between the patient and control groups (17±5° compared to 9±3° [P<0.001]).

CONCLUSION

Patients with planovalgus feet and tarsometatarsal osteoarthritis have greater range of motion of the medial column than controls with normal feet when measured using this technique. Recognition of this association may lead to progress in prevention and treatment.

The first tarsometatarsal joint and its association with hallux valgus

Introduction

The aetiology of hallux valgus is almost certainly multifactoral. The biomechanics of the first ray is a common factor to most. There is very little literature examining the anatomy of the proximal metatarsal articular surface and its relationship to hallux valgus deformity.

Methods

We examined 42 feet from 23 specimens in this anatomical dissection study.

Results

This analysis revealed three distinct articular subtypes. Type 1 had one single facet, type 2 had two distinct articular facets, and type 3 had three articular facets one of which was a lateral inferior facet elevated from the first. Type 1 joints occurred exclusively in the hallux valgus specimens, while type 3 joints occurred exclusively in normal specimens. Type 2 joints occurred in both hallux valgus and normal specimens. Another consistent finding in regards to the proximal articular surface of the first metatarsal was the lateral plantar prominence. This prominence possessed its own articular surface in type 3 joints and was significantly flatter in specimens with hallux valgus (p < 0.001) and the angle with the joint was significantly more obtuse (p < 0.001).

Conclusions

We believe the size and acute angle of this prominence gives structural mechanical impedance to movement at the tarsometatarsal joint and thus improves the stability.

A clinically applicable six-segmented foot model

We describe a multi-segmented foot model comprising lower leg, rearfoot, midfoot, lateral forefoot, medial forefoot, and hallux for routine use in a clinical setting. The Ghent Foot Model describes the kinematic patterns of functional units of the foot, especially the midfoot, to investigate patient populations where midfoot deformation or dysfunction is an important feature, for example, rheumatoid arthritis patients. Data were obtained from surface markers by a 6 camera motion capture system at 500 Hz. Ten healthy subjects walked barefoot along a 12 m walkway at self-selected speed. Joint angles (rearfoot to shank, midfoot to rearfoot, lateral and medial forefoot to midfoot, and hallux to medial forefoot) in the sagittal, frontal, and transverse plane are reported according to anatomically based reference frames. These angles were calculated and reported during the foot rollover phases in stance, detected by synchronized plantar pressure measurements. Repeated measurements of each subject revealed low intra-subject variability, varying between 0.7° and 2.3° for the minimum values, between 0.5° and 2.1° for the maximum values, and between 0.8° and 5.8° for the ROM. The described movement patterns were repeatable and consistent with biomechanical and clinical knowledge. As such, the Ghent Foot model permits intersegment, in vivo motion measurement of the foot, which is crucial for both clinical and research applications.

Investigation of first ray mobility during gait by kinematic fluoroscopic imaging--a novel method

Background

It is often suggested that sagittal instability at the first tarso-metatarsal joint level is a primary factor for hallux valgus and that sagittal instability increases with the progression of the deformity. The assessment of the degree of vertical instability is usually made by clinical evaluation while any measurements mostly refer to a static assessment of medial ray mobility (i.e. the plantar/dorsal flexion in the sagittal plane). Testing methods currently available cannot attribute the degree of mobility to the corresponding anatomical joints making up the medial column of the foot. The aim of this study was to develop a technique which allows for a quantification of the in-vivo sagittal mobility of the joints of the medial foot column during the roll-over process under full weight bearing.

Methods

Mobility of first ray bones was investigated by dynamic distortion-free fluoroscopy (25 frames/s) of 14 healthy volunteers and 8 patients with manifested clinical instability of the first ray. A CAD-based evaluation method allowed the determination of mobility and relative displacements and rotations of the first ray bones within the sagittal plane during the stance phase of gait.

Results

Total flexion of the first ray was found to be 13.63 (SD 6.14) mm with the healthy volunteers and 13.06 (SD 8.01) mm with the patients (resolution: 0.245 mm/pixel). The dorsiflexion angle was 5.27 (SD 2.34) degrees in the healthy volunteers and increased to 5.56 (SD 3.37) degrees in the patients. Maximum rotations were found at the naviculo-cuneiform joints and least at the first tarso-metatarsal joint level in both groups.

Conclusions

Dynamic fluoroscopic assessment has been shown to be a valuable tool for characterisation of the kinematics of the joints of the medial foot column during gait.

A significant difference in first ray flexion and angular rotation between the patients and healthy volunteers however could not be found.

The pathogenesis of hallux valgus

The first ray is an inherently unstable axial array that relies on a fine balance between its static (capsule, ligaments, and plantar fascia) and dynamic stabilizers (peroneus longus and small muscles of the foot) to maintain its alignment. In some feet, there is a genetic predisposition for a nonlinear osseous alignment or a laxity of the static stabilizers that disrupts this muscle balance. Poor footwear plays an important role in accelerating the process, but occupation and excessive walking and weight-bearing are unlikely to be notable factors. Many inherent or acquired biomechanical abnormalities are identified in feet with hallux valgus. However, these associations are incomplete and nonlinear. In any patient, a number of factors have come together to cause the hallux valgus. Once this complex pathogenesis is unraveled, a more scientific approach to hallux valgus management will be possible, thereby enabling treatment (conservative or surgical) to be tailored to the individual.

Mobility of the first ray: review article

Since its introduction by Morton in the early 20th century, first metatarsal instability has been debated as a contributing cause of many foot ailments. Given our evolutionary origins, some instability at the first ray seems inevitable. It makes sense that hypermobility could be the pathology leading to the development of various forefoot disorders. The problem is that it has been difficult to prove. Only in the last decade have there been any devices with which to quantify mobility, and each of the devices measures slightly different variables. However, each of these devices has been shown to be consistent and reliable. Excessive mobility of the first ray probably cannot be considered the only "suspect." With disorders such as hallux valgus and metatarsalgia, environment and footwear may play just as important a role as hypermobility. There are some conclusions, though, that can be safely drawn at this point. * We should define the measures of first ray mobility. One recent study has suggested the terms metatarsal elevation and metatarsal translation to describe two different aspects of the problem. * Simple clinical tools may be as useful as more cumbersome research tools for assessing first ray instability. * First ray mobility on average is increased in patients with hallux valgus. * First ray mobility is increased in some patients with transfer metatarsalgia. * Although some studies show increased elevation or mobility of the first ray in hallux rigidus, other studies do not. The burden is on the current generation of foot and ankle practitioners to resolve the debate of its predecessors. By first defining the measures of instability and then applying them to large populations, the role of hypermobility may be better defined. Then we can debate how best to "fix" the problem!

Evaluation and biomechanics of the first ray in the patient with limited motion

Adequate first ray function is essential to healthy human gait. Controversies still exist about aspects of human structure and function and many newer answers and theories have been proposed by a new generation of experts. Examples include the sagittal plane facilitation, tissue stress, and preferred movement pathway theories. This article also presents a summary of how to provide a thorough, detailed, and accurate first ray examination on the individual with limited motion. This article explores functional first ray mechanics in both a theoretic and biomechanical perspective, as well as a practical, hands-on examination perspective.

The unreliability of the intermetatarsal angle in choosing a hallux abducto valgus surgical procedure

Conventional thinking holds that high intermetatarsal and hallux abductus angles (>15° and >25°, respectively) are associated with a hypermobile first ray and require a Lapidus procedure to achieve satisfactory correction for the treatment of hallux valgus. However, normal first ray motion may be misinterpreted as hypermobility, and it is possible to take advantage of this motion to correct some portion of a large hallux abductovalgus deformity with distal procedures, such as the Austin or first metatarsophalangeal joint fusion. We retrospectively examined radiographs of 61 patients with first intermetatarsal and hallux abductus angles greater than 15° and greater than 25°, respectively, who had undergone hallux abductovalgus correction via Lapidus, Austin, or first metatarsophalangeal joint fusion. Preoperative and postoperative radiographic measurements of the intermetatarsal and hallux abductus angles were made. The results revealed no statistically significant differences in the amount of correction achieved by any of the 3 procedures in comparison with the others. We concluded that, given appropriate patient selection, an Austin or first MTPJ fusion could reliably correct large intermetatarsal and hallux abductus angles that, in the hands of many surgeons, are often treated by means of Lapidus arthrodesis.

Hallux valgus and the first metatarsal arch segment: a theoretical biomechanical perspective

Hallux valgus is a progressive foot deformity characterized by a lateral deviation of the hallux with corresponding medial deviation of the first metatarsal. Late-stage changes may render the hallux painful and without functional utility, leading to impaired gait. Various environmental, genetic, and anatomical predispositions have been suggested, but the exact cause of hallux valgus is unknown. Evidence indicates that conservative intervention for hallux valgus provides relief from symptoms but does not reverse deformity. Part 1 of this perspective article reviews the literature describing the anatomy, pathomechanics, and etiology of hallux valgus. Part 2 expands on the biomechanical initiators of hallux valgus attributed to the first metatarsal. Theory is advanced that collapse of the arch with vertical orientation (tilt) of the first metatarsal axis initiates deformity. To counteract the progression of hallux valgus, we use theory to discuss a possible mechanism by which foot orthoses can bolster the arch and reorient the first metatarsal axis horizontally.

Procedure selection for hallux valgus

Selecting the appropriate surgical procedure for the treatment of hallux valgus not always is clear. Every procedure has its merits depending on the individual and circumstances. Correcting pain and deformity, avoiding recurrence, and preserving or re-establishing normal foot function should be the goals of bunion surgery. Although radiographic measurements can be helpful, their weight is not as important as understanding the function of the first ray in each patient. This article attempts to guide procedure selection based on re-establishing normal foot function as much as possible while meeting patients' goals and expectations.

Meta-analysis of first metatarsophalangeal joint implant arthroplasty

Management of late-stage degenerative joint disease of the first metatarsophalangeal joint (MPJ) is a complex topic that is frequently the source of debate among foot and ankle surgeons. Several surgical interventions have been described to treat this condition. One of the most contested of these treatments is implant arthroplasty of the first MPJ. The primary aim of this meta-analysis was to evaluate the clinical benefit of first MPJ implant arthroplasty in regard to patient satisfaction. Reviewers formally trained in meta-analysis abstraction techniques searched databases and indices using medical subject heading terms and other methods to identify all relevant studies published since 1990. Initially, 3874 citations were identified and evaluated for relevance. Abstract screening produced 112 articles to be read in entirety, of which 47 articles studying 3049 procedures with a mean 61.48 (SD 45.03) month follow-up met all prospective inclusion criteria necessary for analysis. Overall crude patient satisfaction following first MPJ implant arthroplasty was 85.7% (95% confidence interval: 82.5%-88.3%). When adjusting for lower quality studies (retrospective, less than 5 years of follow-up, higher percent of patients lost to follow-up), the overall patient satisfaction increased to 94.5% (89.6%-97.2%) in the highest-quality studies. This adjustment also significantly decreased heterogeneity across studies (crude Q = 184.6, high-quality studies Q = 2.053). Additional a priori sources of heterogeneity were evaluated by subgroup analysis and meta-regression. In regards to patient satisfaction, this comprehensive analysis provides supportive evidence to the clinical benefit of first MPJ implant arthroplasties.

LEVEL OF CLINICAL EVIDENCE

1.

Biomechanics and clinical analysis of the adult acquired flatfoot

The adult acquired flatfoot is a deformity that results from the loss of dynamic and static supportive structures of the medial longitudinal arch. The severity of the deformity is dependent upon the role of ligamentous disruption on the hindfoot that can be determined by careful clinical examination. Treatment of the adult flatfoot requires an understanding of the biomechanical effects of deforming forces, tendon dysfunction, ligament disruption, and joint sublaxation.

A critical analysis of Dudley Morton's concept of disordered foot function

The name Morton is associated with a foot structure characterized by a short first metatarsal in comparison with the adjacent second metatarsal. Dudley Morton is credited with recognizing a short first metatarsal as being a primary defect of the foot. Morton, an anatomist, approached his observation from an evolutionary perspective. His theory of disordered foot function was based on the premise that human alignment centered on an "axis of leverage" and around an "axis of balance." Morton concluded that the presence of a short first metatarsal was compounded when the first metatarsal segment was hypermobile. Shortness and hypermobility diminished the capacity of the first metatarsal segment to carry weight, allowed pronation during activity, and led to an overload of the central metatarsals. The term Morton Foot sprang from his teachings. The extensive writings of Morton are commonly cited even today. This study compares Morton's teachings with research published during the last 70 years, which either supports or refutes his claims.