Biomechanics of the first ray. Part II: Metatarsus primus varus as a cause of hypermobility. A three-dimensional kinematic analysis in a cadaver model

Immediate effect of hallux valgus surgery on the biomechanical behavior of the first ray

BACKGROUND

The surgical treatment of hallux valgus (HV) deformity has been the subject of countless publications but few focus on the altered windlass mechanism or analyze the biomechanical behavior immediately after surgery.

METHODS

Patients treated for HV between January and March 2023 were included. The surgery consisted of a L-reverse first metatarsal osteotomy. To analyze the windlass mechanism we record two different measurements; the isolated first metatarsophalangeal joint (MTPJ) dorsiflexion angle (IDA) and dynamic plantarization of the first metatarsal head when performing first MTPJ dorsiflexion imprinting a mark on a modeling foam.

RESULTS

A total of 30 patients diagnosed with symptomatic HV were included. In all patients, a change in the IDA angle was evident, being overall statistically significant. About modeling foam imprinted mark, all measurements, in all planes of space, had a clear tendency to increase, which turned out to be statistically significant (p < 0.001).

CONCLUSIONS

An altered windlass mechanism may be successfully recovered immediately after hallux valgus deformity surgery. This could be evinced by an indirect measurement analyzing the imprint of the head of the first metatarsal in a modeling foam and the IDA.

LEVELS OF EVIDENCE II

None.

Special Considerations in Podiatric Science: Translational Research, Cadavers, Gait Analysis, Dermatology, and Databases

The objective of this article is to provide a brief overview of the critical analysis and design of unique and perhaps less common methodologies in podiatric science. These include basic science translational designs, cadaveric investigations, gait analyses, dermatologic studies, and database analysis. The relative advantages, disadvantages, and inherent limitations are reviewed with an intention to improve the interpretation of results and advance future foot and ankle scientific endeavors.

Midfoot width changes after first metatarsal osteotomy in hallux valgus surgery: A biomechanical effect?

Hallux valgus is a challenging pathology characterized by a valgus deformity in the metatarsophalangeal area of the first ray. The aim of this study was to analyze the influence of first metatarsal osteotomy on the relationship between midfoot bones in patients with hallux valgus. The sample consisted of patients from the orthopedics and traumatology outpatient clinic who underwent surgical treatment for hallux valgus. Preoperative and postoperative X-rays were compared regarding the width of the midfoot and the tarsometatarsal joint. The sample consisted of 17 women, with 22 feet assessed in each group. The distance from the medial cuneiform to the cuboid, the distance from the intermediate cuneiform to the cuboid, the distance between the first and fifth metatarsals, and the distance between the second and fifth metatarsals reduced significantly between pre- and postoperative assessments. Hallux valgus correction through osteotomy of the first metatarsal leads to a structural change in the midfoot. Further studies should determine whether these changes persist over time.

Medial sesamoid position in moderate to severe hallux valgus: Correlation between three radiographic measurements

BACKGROUND

In hallux valgus surgery, it is essential to accurately assess the position of the sesamoids both pre- and postoperatively. Weight-bearing foot anteroposterior, tangential sesamoid, and semi-weight-bearing computed tomography axial views are radiographic methods used to assess the medial sesamoid position. This study aimed to measure the medial sesamoid position and evaluate the correlation between these three radiographic methods.

METHODS

This retrospective study comprised 59 feet from 49 patients who underwent hallux valgus surgery. The mean age of patients was 54.6 (range, 22-70) years. We took preoperative and postoperative measurements using the weight-bearing anteroposterior, tangential sesamoid, and semi-weight-bearing computed tomography axial views to assess the medial sesamoid position.

RESULTS

The mean grades of the medial sesamoid position preoperatively and 6 months postoperatively were 2.5 and 0.8, 1.6 and 0.4, and 1.3 and 0.3 points based on the anteroposterior, tangential sesamoid, and computed tomography axial views, respectively (P < 0.001). Preoperatively, there was a strong positive correlation between the computed tomography axial and tangential sesamoid views (P < 0.001, r = 0.645) and anteroposterior and computed tomography axial views (P < 0.001, r = 0.468). In contrast, the tangential sesamoid and anteroposterior views showed a weak positive correlation (P = 0.03, r = 0.283). Six months postoperatively, there was a positive correlation between the computed tomography axial and tangential sesamoid views (P < 0.001, r = 0.473), anteroposterior and computed tomography axial views (P < 0.001, r = 0.470), and tangential sesamoid and anteroposterior views (P < 0.001, r = 0.480).

CONCLUSIONS

We observed that the anteroposterior view exhibited a higher degree of medial sesamoid position displacement than the computed tomography axial and tangential sesamoid views. For the preoperative evaluation of the medial sesamoid position, the correlation between the computed tomography axial and tangential sesamoid views was stronger than that between the tangential sesamoid and anteroposterior views. However, all three views showed strong correlations postoperatively.

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.

Is there a tolerance for extension of the first metatarsal after the Lapidus procedure? A clinical, functional, and hindfoot radiographic analysis

PURPOSE

Based on the tripod concept of load distribution, our study aimed to evaluate whether a slight extension of first metatarsal (M1) that may occur after the Lapidus procedure (LP) could alter the radiographic measurements of the hindfoot and influence clinical and functional outcomes.

METHODS

Twenty-five patients (27 feet) were reviewed. Hindfoot radiographic analysis was based on seven measurements. Clinical and functional outcomes were evaluated with self-reported questionnaires. Transfer metatarsalgia was also assessed. Correlation analysis was performed according to variations of the studied variables.

RESULTS

The average extension of the M1 was 4.26 degrees (p < 0.001). None of the hindfoot radiographic measurements changed significantly (p = 0.13, p = 0.50, p = 0.19, p = 0.70, p = 0.11, p = 0.36, p = 0.83). Patients improved on most questionnaires (p < 0.001). None presented transfer metatarsalgia. No correlation between M1 extension and clinical and functional outcomes was found.

CONCLUSION

Possibly there is a tolerance of M1 extension in which it does not alter the radiographic measurements of the hindfoot, overload the lesser metatarsals, or compromise clinical and functional outcomes.

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.

Addressing Medial Column Instability in Flatfoot Deformity

A stable medial column is important to the normal function of the foot and ankle. Medial column instability and forefoot varus can result in compensatory hindfoot motion leading to stress along the medial soft-tissue structures. Medial column stabilization should therefore be considered when (1) forefoot varus deformity is identified following hindfoot realignment; (2) pronounced medial column instability is present, even in the absence of forefoot varus; and (3) when degenerative changes are present within the medial column articulations. Common surgical procedures include arthrodesis of the talonavicular joint, naviculocuneiform joint, and first tarsometatarsal joint, as well as osteotomy of the medial cuneiform (Cotton osteotomy).

First Tarsometatarsal Joint Arthrodesis for Hallux Valgus With and Without Intermetatarsal Screw Fixation: A Comparison of Correction and Maintenance of Correction

Tarsometatarsal joint arthrodesis is a commonly accepted procedure for hallux valgus associated with severe deformity and first ray hypermobility or medial column instability. This study evaluates the correction of hallux valgus deformity and the maintenance of correction with and without the use of a stabilization screw between the first and second metatarsal bases. Through retrospective review of first tarsometatarsal joint arthrodesis within our institution we evaluated 63 patients. Twenty-seven patients did not have a first to second metatarsal base screw and were placed into the no screw cohort. Thirty-six patients did have a first to second metatarsal base screw and were placed into the screw cohort. This study population had an osseous union rate of 95%. Clinical and radiographic recurrence occurred in 5 of 63 patients (8%). At 1-y postop the measurements demonstrated that the screw cohort had an average intermetatarsal angle correction of 11.6 degrees while the no screw cohort had an average correction of 7.8 degrees. Additionally, at 1-y postop the screw cohort had greater maintenance of the intermetatarsal angle correction with an average change of 0.5 degrees compared to 2.3 degrees in the no screw cohort. We conclude that the addition of the stabilization screw improves the first tarsometatarsal joint arthrodesis construct resulting in a greater degree of realignment and maintenance of correction.

Intraoperative Technical Tips to Improve Fusion Between the First and Second Metatarsals in the Original Lapidus Procedure

The modified Lapidus procedure (MLP), which consists of fusion between the first metatarsal (M1) and medial cuneiform, has been widely performed with satisfactory clinical outcomes, but it has a variable nonunion rate ranging between 4% and 10% and loss of correction in up to 5.8% of the cases. Excessive motion around the site of tarsometatarsal arthrodesis, specially at the intercuneiform joint, is probably the reason. The original Lapidus procedure (OLP), which includes fusion of the M1 to second metatarsal (M2), may be beneficial in preventing nonunion and recurrence. The objective of this study was to describe intraoperative technical tips in the OLP to improve M1 to M2 fusion, which may prevent complications. Since the Lapidus procedure continues to gain popularity, it is the authors opinion that the OLP requires special attention because it is a more technically demanding surgery compared to the MLP.Level of Evidence: Level V: Expert opinion.

Correlation of first metatarsal sagittal alignment with clinical and functional outcomes following the Lapidus procedure

BACKGROUND

The purpose of this study was to evaluate the effect of the variation of the first metatarsal (M1) sagittal alignment after the Lapidus procedure (LP) on clinical and functional outcomes, and transfer metatarsalgia.

METHODS

Twenty-nine patients who underwent a LP, with a mean follow-up of 20 months, were reviewed. Radiographic, clinical and functional measurements were compared. Clinical and functional questionnaires applied were the visual analogue scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS) scale, lower extremity functional scale (LEFS) and SF-12, which is divided in physical (PCS-12) and mental-health (MCS-12) scales. Radiographic analysis of M1 sagittal alignment was based on the first metatarsal declination angle (FMDA) and Meary Angle (MA). Intermetatarsal angle (IMA) and hallux valgus angle (HVA) were also measured.

RESULTS

FMDA, IMA and HVA showed significant variation, but MA did not. Clinical and functional improvements were observed, except in MCS-12. No patient developed transfer metatarsalgia. A direct correlation was found between Δ-FMDA with Δ-PCS-12 and Δ-LEFS, meaning that excessive M1 dorsiflexion as measured by FMDA led to a decrease in PCS-12 and LEFS. Patients with Δ-FMDA of up to 3.2° of dorsiflexion were those who had significant improvements.

CONCLUSION

Dorsiflexion of M1 can lead to decreased outcomes as measured by PCS-12 and LEFS. However, satisfactory outcomes can be obtained even with some dorsal deviation of the M1.

LEVEL OF EVIDENCE

IV, retrospective case series.

A Prospective Study Comparing the Efficacy of Local Injection of Platelet-Rich Plasma (PRP) vs Methylprednisolone in Plantar Fasciitis

Introduction

Plantar fasciitis is a common musculoskeletal problem in Orthopaedic practice. Heel pain caused due to plantar fasciitis, if persistent, can cause distress to the patient, so the correct intervention at the right time is needed. Plantar fasciitis is also common in the rural population.

Objectives

To compare the efficacy of local injection of platelet-rich plasma (PRP) and corticosteroid (CS) (methylprednisolone) in patients with chronic plantar fasciitis, and to evaluate the safety, side effect and complications of two different modalities of treatment.

Materials and methods

The study period was between August 2018 and September 2020. After obtaining proper written consent, 110 patients, who were above the age of 18 years and suffering from plantar fasciitis for more than three months, were included in the study. The patient characteristics including gender, age, weight, history of heel pain, duration of symptoms and types of prior treatment were noted. All the 110 patients were subjected to four parameter assessments before administration of the PRP/CS injections. Out of the 110 patients, 55 patients received PRP injection and 55 received CS - 2 ml (40 mg) methylprednisolone with 2 ml of sterile water injections. Post administration of injections, the patients' clinical, radiological, subjective and functional outcomes were assessed at the first, third and sixth month by using the Visual Analog Scale (VAS), Foot and Ankle Outcome Instrument Core Scale (FAI), Roles and Maudsley Scores (RMS), American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hind foot scale and ultrasonogram of plantar fascia thickness.

Discussion

In this study, 110 patients were screened and evaluated. Out of these 110 patients, five patients who received PRP and five who received CS were lost for follow-up. Out of the 110 patients, 59 were females and 41 were males. The majority of the patients were in the BMI range of 18.5 to 24.9, with a mean BMI of 23.6. Comparing the results in both the groups reflected an improvement in the group of patients who received PRP injections. Two patients had post-operative complications (superficial infection) in the PRP injection group, while 10 patients had post-procedure complications (five patients developed superficial infections, three patients developed skin depigmentation, and two patients had atrophy of fat pad) in the corticosteroid injections (CSI) group. Infections subsided in all the patients as observed during subsequent follow-up.

Conclusion

This study shows that PRP administration is a good method of managing patients suffering from chronic plantar fasciitis, presenting with some discomfort following activity, with more than three months of symptoms and with a VAS score of more than 6 and plantar fascia thickness of 5 mm and failed conservative management. This is evidenced by a comparison of AOFAS, FAI score and thickness of plantar fascia using an ultrasonogram before and after the procedure. This study reflects better treatment outcomes with PRP injection compared to local steroid infiltration. This is the largest series of cases studied compared to other previously available studies in the literature. PRP injections may thus be used as a superior alternative to the already available treatments for chronic heel pain.

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.

Is first metatarsal shortening correlated with clinical and functional outcomes following the Lapidus procedure?

OBJECTIVE

To correlate first metatarsal (M1) shortening with transfer metatarsalgia, and clinical and functional outcomes in patients who underwent the Lapidus procedure (LP).

MATERIALS AND METHODS

A retrospective review of 29 patients who were submitted to the LP for HV correction. The average follow-up was 20 months. M1 length was analyzed using the Relative First Metatarsal Length (RML) measurement. Intermetatarsal angle (IMA) and hallux valgus angle (HVA) were also measured. Clinical and functional analyses were based on the visual analogue scale (VAS), Lower Extremity Functional Scale (LEFS), and Short-form 12 (SF-12) health survey. SF-12 is divided into physical (PCS-12) and mental health (MCS-12) composite scales. Transfer metatarsalgia was diagnosed by the clinical exam. Radiographic, clinical, and functional outcomes were compared using paired Wilcoxon's and Student's t tests. Inter-observer reliability of RML measures was calculated using Intraclass Correlation Coefficients (ICC). The correlation between RML and the clinical and functional questionnaires was assessed with the Spearman's Rho test.

RESULTS

There was a significant M1 shortening of 2.3 mm (p < 0.05), with mean preoperative RML of 3 mm and mean post-operative of 5.3 mm. None of the patients evolved with transfer metatarsalgia. ICC of the RML measures presented excellent reliability. IMA and HVA showed improvements (p < 0.05). Clinical and functional improvements were observed in all questionnaires applied, except in the MCS-12. In the linear regression, RML was inversely correlated to LEFS (p < 0.05), which means that LEFS scores increased as RML measurements decreased.

CONCLUSION

The present study demonstrated that M1 shortening led to a decreased LEFS following the LP.

The Realign-Resect Arthrodesis Technique

During traditional fusion procedures surgeons initially perform a joint resection and then the structures are realigned for correction of deformity. The procedure described herein by the author reverses this traditional surgical approach by first realigning the joint to correct deformity, then after achieving a corrected alignment, joint resection is performed in parallel without wedging. Realigning deformity as an initial step creates the conditions for an in-situ fusion wherein the deformity is corrected simultaneously with parallel bone resection. The purpose of this paper is to review the advantages and technical aspects of a realignment arthrodesis technique in which joint resection begins with the foot in the corrected position. This approach to joint fusion has been shown to simplify bone resection, eliminate post-resection adjustments, create full apposition of fusion surfaces, reliably correct deformity, and result in solid arthrodesis. The technique provides for immediate correction of deformity and is amenable for conditions that require either minimal or significant segmental shortening. There are many areas where the "Realign-resect" approach to joint fusion would be well suited. Full implementation of this technique may be particularly useful to the surgeon who does not have seasoned assistants in the operating room.

Effect of the First Tarsometatarsal (Modified Lapidus) Arthrodesis on Hindfoot Alignment

The purpose of this study is to demonstrate the effect of first tarsometatarsal (modified Lapidus) arthrodesis on hindfoot alignment. We reviewed the radiographs of 39 patients, 40 feet (16 right feet and 24 left feet in 6 males and 34 females; mean age 43 years) who underwent hallux valgus reconstruction and isolated first tarsometatarsal arthrodesis. Patients who had ancillary osseous procedures were excluded from the study, with the exception of proximal phalangeal osteotomy to address hallux interphalangeus. The mean time to follow up was 33.78 weeks (8.45 months), median 21.5 weeks. Statistically significant differences were found between preoperative and postoperative measurements for talar declination (-3.3 ± 3.5), lateral talocalcaneal angle (-3.1 ± 3.9), lateral Meary's angle (-4.2 ± 4.9), medial cuneiform height (3.5 ± 4.6), medial cuneiform to fifth metatarsal distance (4.7 ± 4.5), AP talocalcaneal angle (-2.8 ± 5.3), and percentage of talar head uncovering (-6.6 ± 7.6). Our results suggest that first tarsometatarsal arthrodesis can affect hindfoot alignment on AP and lateral radiographs.

First ray alignment in Lapidus arthrodesis - Effect on plantar pressure distribution and the occurrence of metatarsalgia

BACKGROUND

Lapidus arthrodesis is an established treatment option for severe hallux valgus deformity especially in patients suffering from instability of the first tarsometatarsal joint. Surgery related metatarsalgia is known to be associated with persistent elevation of the first ray after realignment surgery. Nevertheless, detailed information on ideal positioning of the first ray in Lapidus surgery is missing so far. This study was designed to determine any correlations between radiographic and pedobarographic outcome following the Lapidus procedure with regard to clinical outcome and the occurrence of metatarsalgia.

METHODS

Thirty feet (28 patients) after Lapidus surgery were available for follow-up at 42.5±21.0 months. All subjects had radiographic and pedobarographic evaluation of the operated foot and patient satisfaction was recorded using questionnaires.

RESULTS

Metatarsalgia was associated with a poorer outcome in FADI and AOFAS scores (p<0.005). A lateral shift of plantar pressure distribution to the third metatarsal head in these cases could be observed. Although Lapidus surgery resulted in significant shortening of the first metatarsal, no correlation to the occurrence of metatarsalgia was detectable. Likewise, axial plane malalignment showed no influence, whereas elevation of the first ray was highly correlated to surgery related metatarsalgia (p=0.007). Subjects suffering from metatarsalgia had a higher BMI (body mass index), but its effect on metatarsalgia turned out not to be significant (p=0.090).

CONCLUSION

In Lapidus surgery realignment of the first metatarsal in the sagittal plane seems to be decisive for good clinical outcome. Failing to plantarflex the arthrodesis resulted in a lateral shift of plantar loading with overload of the lesser metatarsals and the occurrence of metatarsalgia.

A Narrative Review on the Tests Used in Biomechanical Functional Assessment of the Foot and Leg: Diagnostic Tests of Deformities and Compensations

BACKGROUND

To date, scientific literature has not as yet come up with any review showing the diagnostic tests used for functional assessment of the foot and leg.

METHODS

A literature review was conducted of electronic databases (MEDLINE, PEDro, DOAJ, BioMed Central, PLOS, and Centre for Reviews and Dissemination at the University of York) up to December 8, 2018. The biomechanical tests, which have adequate supportive literature, were divided into qualitative tests that provide a dichotomy/trichotomy-type answer to clinical diagnostic questions; semiquantitative tests that provide numerical data to clinical diagnostic questions; and quantitative tests that record continuous numerical data (in analogue or digital form).

RESULTS

These tests produce a useful functional evaluation model of the foot and leg for different purposes: evaluation of lower limb deficits or abnormalities in healthy patients and in athletes (in sports or other physical activities); assessment of tissue stress syndromes caused by pathomechanics; evaluation of lower limb deficits or abnormalities in rheumatic disease and diabetic foot patients; and to determine the appropriate functional or semifunctional foot orthotic therapy and therapeutic path used in gait rehabilitation.

CONCLUSIONS

Many of these tests have adequate diagnostic reliability and reproducibility and therefore can be considered diagnostic. Few of these are validated, and some have initiated the validation process by determining their sensitivity and specificity. The widespread use of these tools in clinical practice (diagnosis of function) lacks scientific evidence and in-depth analysis of their limitations.

Analysis of Shortening and Elevation of the First Ray With Instrumented Triplane First Tarsometatarsal Arthrodesis

BACKGROUND

The Lapidus procedure using planar saw resection has often been criticized for complications related to excessive shortening and elevation of the first ray. The goal of this study was to assess the amount of shortening that occurs when using a cutting guide for controlled saw resection of the first tarsometatarsal (TMT) joint surfaces, along with assessment of deformity correction in all 3 anatomic planes.

METHODS

A prospective multicenter study with IRB approval included 35 hallux valgus subjects evaluated at baseline and 6 months following instrumented triplane first TMT arthrodesis without lesser metatarsal osteotomies.

RESULTS

The average first ray bone segment length loss was 3.1 mm (95% confidence interval [CI] 2.4-3.7) in the anteroposterior (AP) radiographic assessment and 2.4 mm (95% CI 1.7-3.1) in the sagittal plane. The mean preoperative radiographic measurements were 1.7 degrees (dorsiflexion) for sagittal plane angle, 13.8 degrees for intermetatarsal angle (IMA), and 5.1 for tibial sesamoid position (TSP). Improvements were seen postoperatively for all measures with a mean difference of -0.2 degrees (95% CI -1.0 to 0.6) for sagittal plane angle, -9.2 degrees (95% CI -10.1 to -8.3 degrees) for IMA, and -3.5 (95% CI -4.0 to -3.1) for TSP. Five of the patients reported lesser metatarsal pain preoperatively, and no patients complained of lesser metatarsalgia at 6-month follow-up.

CONCLUSIONS

Minimal length loss of the first ray can be expected following instrumented triplane TMT arthrodesis while achieving full 3-dimensional deformity correction and reducing the risk of lesser metatarsalgia.

LEVEL OF EVIDENCE

Level II, prospective 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)

Hypermobility in Hallux Valgus

The interaction between hypermobility and hallux valgus remains both contemporary and incendiary. The difficulty in setting clinical and radiological parameters to diagnose and the complexity of questions that circumnutate the philosophy among etiology and denouement, fires up the debate regarding these conditions. Outcomes among procedures that address or neglect ray instability are still used as argument for any group of believers or nonbelievers. Through proving the true existence of hypermobility and its relationship with bunions, our colleges and professors have produced an incredible amount of excellent data that helped us better comprehend the hallux valgus syndrome in a general manner.

Medial Column Biomechanics: Nonsurgical and Surgical Implications

Understanding of medial column biomechanics is paramount to a successful outcome in both conservative and surgical treatment. Dysfunctions of the dynamic stabilizers as well as the static stabilizers of the medial column play a role in pathomechanics. Conservative options for addressing the medial column include custom foot orthotics and bracing. Options for addressing the medial column surgically with the goal to restore a stable tripod configuration, include first tarsometatarsal joint arthrodesis, opening plantarflexory medial cuneiform osteotomy, and naviculocuneiform arthrodesis.

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.

Properties and Function of the Flexor Hallucis Capsularis Interphalangeus Tendon

INTRODUCTION

The fibrocartilagenous plantar plates of the forefoot are biomechanically important, forming the primary distal attachment for the plantar aponeurosis. They are integral to the function of the windlass mechanism in supporting the arches of the foot in gait. Dissection of the cadaveric hallux revealed an organised sagittal thickening of the dorsal side of the flexor hallucis longus (FHL) sheath, which attached the interphalangeal plantar plate to the metatarsophalangeal (MTP) plantar plate. A description of a similar structure was made in 1984 when it was termed the flexor hallucis capsularis interphalangeus (FHCI) - however, it has not been researched since, and we aim to study it further and identify its characteristics.

METHOD

Eight specimens were dissected from four cadavers. Two were stained and examined under magnification in both polarized and non polarized light. The remaining 6 were subjected to micrometer testing of their tensile properties.

RESULTS

Both the histological features and mechanical properties were consistent with tendon; with cross sectional area, ultimate tensile strength and stiffness varying between specimens.

CONCLUSIONS

Based on its location and properties, the FHCI tendon may be involved in limiting dorsiflexion of the first MTP joint and could have clinical relevance in pathological processes around both the first and second MTP joints. Clin. Anat., 33:689-695, 2020. © 2019 Wiley Periodicals, Inc.

Hallux Valgus

Hallux valgus is a common condition that results from a complex positional deformity of the first ray. The bunion or medial prominence that results from the lateral deviation and pronation of the hallux is only one component of the 3-dimensional deformity. Hallux valgus can lead to considerable pain and altered joint mechanics. The precise biomechanical etiology remains under debate. Predisposing factors include female sex, age, constricting footwear, and family history. Metatarsus adductus, equinus contracture, hammertoe deformity, and pes planus often coexist with hallux valgus. Nonoperative treatment involves patient education, shoe modifications, toe pads and positioning devices, and activity modifications. Surgery is considered in patients who fail nonoperative treatment with the goal of pain relief, correction of the deformity, improved first ray stability, and improved quality of life. More than 100 different procedures have been described to treat hallux valgus; they include combinations of soft tissue balancing, metatarsal osteotomies, and fusion of either the metatarsophalangeal (MTP) or tarsometatarsal (TMT) joint. The choice of procedures depends on the severity and location of the deformity as well as surgeon preference. Recent advances in operative techniques include minimally invasive surgery and correction of rotational deformity.

First ray mobility and posterior tibial tendon dysfunction (PTTD) in persons with flatfoot: A case control study

BACKGROUND

While posterior tibial tendon dysfunction (PTTD) commonly presents with flat feet and has been thought to be associated with first ray mobility, many flat-footed individuals are asymptomatic and do not experience any symptoms of PTTD. Thus, there is a need to control for foot type when studying factors related to PTTD. This study aimed to clarify if first ray mobility differed between flat-footed individuals with and without symptoms of PTTD. It was hypothesized that PTTD patients would display higher mobility of the first ray than asymptomatic flat-footed controls.

METHODS

Given that PTTD patients were often flat-footed, asymptomatic flat-footed individuals were chosen as controls to remove flatfoot as a potential confounding factor. We recruited 32 flat-footed subjects, of which 16 exhibiting PTTD symptoms and 16 asymptomatic controls matched for age, sex and body mass index. First ray mobility was assessed using subjective classification ("stiff", "normal" or "hypermobile") and maximum dorsal displacement using a ruler indicator. Mann-Whitney U was used to test for between-groups differences.

RESULTS

Subjective classification was similar between PTTD and control groups (both groups: 38% "normal" joint mobility). No significant differences were found between PTTD patients and asymptomatic controls in first ray displacement [median (IQR), PTTD: 6.00 (1.75) mm; control: 6.00 (1.00) mm; P=.31].

CONCLUSIONS

First ray mobility was not associated with PTTD in flat-footed persons. When evaluating symptoms of PTTD, clinicians should pay attention to factors other than first ray mobility.

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.

Effect of First Tarsometatarsal Joint Derotational Arthrodesis on First Ray Dynamic Stability Compared to Distal Chevron Osteotomy

BACKGROUND

Hallux valgus alters gait, compromising first ray stability and function of the windlass mechanism at the late stance. Hallux valgus correction should restore the stability of the first metatarsal. Comparative studies reporting the impact of different hallux valgus correction methods on gait are rare. We report the results of a case-control study between distal chevron osteotomy and first tarsometatarsal joint derotational arthrodesis (FTJDA).

METHODS

Two previously studied hallux valgus cohorts were matched: distal chevron osteotomy and FTJDA. Seventy-seven feet that underwent distal chevron osteotomy (chevron group) and 76 feet that underwent FTJDA (FTJDA group) were available for follow-up, with a mean of 7.9 years (range, 5.8-9.4 years) and 5.1 years (range, 3.0-8.3 years), respectively. Matching criteria were the hallux valgus angle (HVA) and a follow-up time difference of a maximum 24 months. Two matches were made: according to the preoperative HVA and the HVA at late follow-up. Matching provided 30 and 31 pairs, respectively. Relative impulses (%) of the first toe (T1) and metatarsal heads 1 to 5 (MTH1-5), weightbearing radiographs, and American Orthopaedic Foot & Ankle Society (AOFAS) (hallux metatarsophalangeal-interphalangeal [MTP-IP]) scores were studied.

RESULTS

The relative impulse of MTH1 was higher in the FTJDA group, whereas a central dynamic loading pattern was seen in the chevron group. This result remained when relative impulses were analyzed according to the postoperative HVA. The mean difference in the HVA at follow-up was 6.2 degrees (95% confidence interval, 3.0-9.5; P = .001) in favor of the FTJDA group.

CONCLUSION

The dynamic loading capacity of MTH1 was higher in the FTJDA group in comparison to the chevron group. The follow-up HVA remained better in the FTJDA group.

LEVEL OF EVIDENCE

Level III, case-control study.

Stability of Lisfranc injury fixation in Thiel Cadavers: Is routine fixation of the 1st and 3rd tarsometatarsal joint necessary?

BACKGROUND

There is debate as to whether a home run screw (medial cuneiform to 2nd metatarsal base) combined with k-wire fixation of the 4th & 5th tarsometatarsal joints is sufficient to stabilise Lisfranc injuries or if fixation of the 1st and 3rd tarsometatarsal joints is also required. Unlike the 2nd, 4th and 5th tarsometatarsal joints, stabilisation of the 1st and 3rd requires either intra-articular screw or an extra-articular plate which risk causing chondrolysis and/or osteoarthritis. The aims of this cadaveric study were to determine if routine fixation of the 1st and 3rd tarsometatarsal joints is necessary and to determine if a distal to proximal home run screw is adequate.

METHODS

Using 8 Theil-embalmed specimens, measurements of tarsometatarsal joint dorsal displacement at each ray (1st-5th) and 1st-2nd metatarsal gaping were made during simulated weight bearing with sequential ligamentous injury and stabilisation to determine the contribution of anatomical structures and fixation to stability.

RESULTS

At baseline, mean dorsal tarsometatarsal joint displacement of the intact specimens during simulated weight bearing (mm) was: 1st: 0.14, 2nd: 0.1, 3rd:0, 4th: 0, 5th: 0.14. The 1st-2nd intermetatarsal gap was 0mm. After transection of the Lisfranc ligament only, there was 1st-2nd intermetatarsal gaping (mean 4.5mm), but no increased dorsal displacement. After additional transection of all the tarsometatarsal joint ligaments, dorsal displacement increased at all joints (1st: 4.5, 2nd: 5.1, 3rd: 3.6, 4th: 2, 5th: 1.3). Stabilisation with the home run screw and 4th and 5th ray k-wires virtually eliminated all displacement. Further transection of the inter-metatarsal ligaments increased mean dorsal displacement of the 3rd ray to 2.5mm. K-wire fixation of the 3rd ray completely eliminated dorsal displacement.

CONCLUSIONS

The results of this cadaveric study suggest that stabilising the medial cuneiform to the 2nd metatarsal base combined with stabilisation of the 4th and 5th tarsometatarsal joints with K-wires will stabilise the 1st and 3rd tarsometatarsal joints if the inter-metatarsal ligaments are intact. Thus 3rd TMTJ stability should be checked after stabilising the 2nd and 4/5th. Provided the intermetatarsal ligaments (3rd-4th) are intact, the 3rd ray does not need to be routinely stabilised.

Loading pattern of postoperative hallux valgus feet with and without transfer metatarsalgia: a case control study

Background

Postoperative transfer metatarsalgia is a common complication after hallux valgus surgeries. Shortening of the first metatarsal is traditionally thought to be the primary cause of it. However, we speculate the abnormal loading pattern during gait is the real reason. This study is to determine specific differences in the loading patterns between reconstructive hallux valgus (HV) feet with and without postoperative transfer metatarsalgia, so as to find risky loading characteristics of this complication.

Methods

Thirty feet with postoperative transfer metatarsalgia were recruited as pain group, while another 30 postoperative feet without pain as controls. All participants were asked to walk barefoot at self-selected speed through a plantar force measuring plate (Rs-Scan Inc.) for three times. Certain plantar load variables were recorded or calculated, and their differences between two groups were compared.

Results

For pain group, the maximum plantar force and force time integral of the first metatarsal decrease significantly; the force time integral of the central rays (second plus third metatarsal) does not significantly differ with that in the controls, but their cumulative load percentage to the whole foot is higher. In pain group, the time point when central rays reached their peak force during the push-off is significantly later than that in controls. And the regional instant load percentage at this moment presented significantly higher for central rays, while significantly lower for the first metatarsal and the hallux compared to the controls.

Conclusions

For hallux valgus feet with postoperative metatarsalgia, the load function of the first metatarsal is obviously impaired. But for central rays, indicative difference is not reflected in either peak or cumulative load during the gait cycle, but in the instant load distribution when central rays reach their peak load. So we can conclude that whether the remaining regions can adequately share certain load during walking, especially around the time metatarsalgia often occurs, plays an unnegligible role. So surgeons should pay more attention to reconstruct a foot where load can be evenly distributed.

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.

Metatarsus Primus Varus Correction

We present a discussion on the use of proximal first-ray osteotomies in the surgical treatment for hallux valgus as a valid option compared with first-tarsometatarsal arthrodesis. Recent and historical literature tells us that stability of the first ray is a function of the alignment and reestablishment of retrograde stabilizing forces at the first tarsometatarsal joint. This realignment and stabilization may be accomplished with the use of distal soft tissue and proximal osteotomy procedures.

The radiographic effects of the scarf bunionectomy on rearfoot alignment

STATEMENT OF PURPOSE

Excessive pronation of the rearfoot has been implicated as a destabilizing force in the progression of hallux abducto valgus. Although the scarf bunionectomy has been shown to effectively correct the intermetatarsal angle associated with hallux valgus deformity, its effect on the rearfoot has yet to be established. The purpose of this case series is to demonstrate the effect of the scarf bunionectomy on rearfoot alignment.

METHODOLOGY

Medical records were reviewed to isolate patients who underwent unilateral or bilateral scarf bunionectomies (with or without akin osteotomy) who had complete medical records, follow-up of at least 12 months, and met the inclusion/exclusion criteria. Preoperative and postoperative radiographic measurements were analyzed at various postoperative time intervals. Standard deviations and statistical significance was obtained.

RESULTS

One hundred feet (71 patients) were included in this analysis. The long-term results of this study highlighted the scarf osteotomy's ability to affect the medial longitudinal arch by decreasing the intermetatarsal angle and lateral talar-first metatarsal angle. The talar declination and calcaneal inclination angle were not significantly altered with the scarf bunionectomy.

CONCLUSION

This case series demonstrates that the scarf bunionectomy had significant effect on radiographic alignment of the bunion deformity and medial longitudinal arch over time. However, its effect on the rearfoot position was not statistically significant.

LEVELS OF EVIDENCE

Therapeutic, Level IV: Case Series.

Intraoperative evaluation of medial intercuneiform instability after Lapidus arthrodesis: intercuneiform hook test

The presence of intercuneiform instability is not routinely inspected within the overall surgical management of hallux valgus and has therefore been underreported as a potential cause of recurrence. We sought to demonstrate the incidence of this unique type of proximal instability to state its potential importance in the correction and definitive management of hallux valgus in patients with moderate to severe intermetatarsal angles with superimposed hypermobility. A total of 34 patients underwent 38 tarsometatarsal arthrodeses for hallux valgus correction and were retrospectively reviewed for 36 months from May 2007 to May 2010. The incidence of intercuneiform instability was 73.68% and was determined by the findings of the intraoperative "hook" test. The high rate of proximal instability could warrant consideration for routine intermetatarsal arthrodesis as a component of this procedure. A technique for evaluating the presence of intercuneiform instability after Lapidus arthrodesis is also presented.

Biomechanics of first ray hypermobility: An investigation on joint force during walking using finite element analysis

Hypermobility of the first ray is suggested to contribute to hallux valgus. The investigation of first ray hypermobility focused on the mobility and range of motion that based on manual examination. The load transfer mechanism of the first ray is important to understand the development and pathomechanism of hallux valgus. In this study, we investigated the immediate effect of the joint hypermobility on the metatarsocuneiform and metatarsophalangeal joint loading through a reduction of the stiffness of the foot ligaments. A three-dimensional foot model was constructed from a female aged 28 via MRI. All foot and ankle bones, including two sesamoids and the encapsulated bulk tissue were modeled as 3D solid parts, linking with ligaments of shell elements and muscles connectors. The stance phase of walking was simulated by the boundary and loading conditions obtained from gait analysis of the same subject. Compared with the normal foot, the hypermobile foot had higher resultant metatarsocuneiform and metatarsophalangeal joint forces. The increases accounted for 18.6% and 3.9% body weight. There was also an abrupt change of metatarsocuneiform joint force in the medial-lateral direction. The predicted results represented possible risk of joint problems and metatarsus primus varus.

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.

Scarf osteotomy

The term scarf osteotomy was first used by Weil when presenting his results from more than 1000 cases. Scarf is a carpentry term describing beveling the ends of 2 pieces of wood and securely fastening them so that they overlap to create one continuous piece. This technique was popularized by Weil and Barouk as a versatile method of correcting hallux valgus while maintaining the blood supply to the metatarsal head. It also has rigid fixation, allowing early mobilization. This article addresses the surgical technique of the scarf osteotomy together with the results and complications of hallux valgus correction.

Immediate weightbearing after Lapidus arthrodesis with external fixation

A common surgical treatment of severe hallux abductovalgus deformity with coincident first ray hypermobility is metatarsal-cuneiform fusion or Lapidus procedure. The aim of the present study was to illustrate a reliable and novel method of fixation for Lapidus fusion using an external fixation device through a retrospective cohort investigation of consecutive patients. Twenty Lapidus fusions were performed in 19 patients, including 17 females (89.47%) and 2 males (10.53%). The mean age at surgery was 41 (range 20 to 64) years. The patients were evaluated clinically and radiographically pre- and postoperatively. The mean duration in the fixator was 12 (range 3 to 34) weeks. The mean interval to radiographic union was 9.2 (range 4.7 to 30.7) weeks in 18 of 20 feet (90%) and 2 (10%) were designated as nonunion. The mean follow-up period was 37 (range 5.6 to 211.1) weeks. The most common complication was pin tract infection in 5 patients (6 feet) and was treated with oral antibiotics; only 1 foot required early hardware removal. According to the visual analog scale, the mean patient pain score decreased significantly from 8.2 ± 2.7 to 0.83 ± 0.98 postoperatively (p < .001). Our results highlight that immediate weightbearing after Lapidus fusion with external fixation is a viable treatment option for the correction of severe hallux abductovalgus with associated hypermobility.

First metatarsal base osteotomies for hallux abducto valgus deformities

Proximal first metatarsal osteotomies have historically been associated with and limited to treatment of severe hallux valgus deformities. These procedures are powerful in deformity correction and overall realignment of first ray function because of their ability to correct closer to the deformity's origin. When considering all factors in bunion correction, they are good options for correction of a wide range of hallux abducto valgus deformities. This article discusses the use of proximal metatarsal osteotomies for correction of hallux valgus deformity, techniques to facilitate optimal outcome, and common complications of these osteotomies.

Correction of frontal plane rotation of sesamoid apparatus during the Lapidus procedure: a novel approach

The Lapidus procedure affords correction of a multitude of first ray pathologic entities. When reconstructing the first ray using the Lapidus procedure, the relocation of the first metatarsal over the sesamoid bones with frontal plane rotation should be considered one of the key components. In the present technical report, we have described a bunion correction with emphasis on sesamoid reduction through indirect frontal plane manipulation. Our technique, borne from applied basic anatomy of the first metatarsophalangeal joint, uses intact soft tissues about the first metatarsophalangeal joint to reduce subluxed or dislocated sesamoids.

First tarsometatarsal joint derotational arthrodesis--a new operative technique for flexible hallux valgus without touching the first metatarsophalangeal joint

No operative technique for hallux valgus has been introduced in which the first metatarsophalangeal joint is not touched. We report the first tarsometatarsal joint derotational arthrodesis in which we mimic the function of the peroneus longus tendon without involving the first metatarsophalangeal joint, allowing function of the windlass mechanism without interference. We treated 66 patients (62 women and 4 men) with 84 flexible hallux valgus feet using our new operative technique. Preoperative and postoperative follow-up weightbearing radiographs were evaluated. Most patients had a pronation type foot (78%) preoperatively, and mean correction in hallux valgus and intermetatarsal angle was 20° and 9°, respectively (p < .001). The LaPorta classification showed a median change of 2.5 U (p < .001). We have described a new operative technique for flexible hallux valgus. The first tarsometatarsal joint derotational arthrodesis showed notable correction angles in hallux valgus, although the first metatarsophalangeal joint was left intact.

Hallux valgus and hypermobility of the first ray: facts and fiction

The aetiology of hallux valgus with regard to stability of the first metatarsocuneiform joint has historically been subject to much debate. Associations between the magnitude of the intermetatarsal angle and the hallux valgus angle have previously been established. Metatarsocuneiform joint coronal plane mobility is necessary for a concomitant increase in both of these angles. Although metatarsocuneiform joint hypermobility has been implicated in the development of a hallux valgus deformity, isolated sagittal plane instability has thus far not been proven to be a definitive cause.

Hypermobility of the first metatarsal bone in patients with rheumatoid arthritis treated by Lapidus procedure

Background

Foot deformities and related problems of the forefoot are very common in patients with rheumatoid arthritis. The laxity of the medial cuneometatarsal joint and its synovitis are important factors in the development of forefoot deformity. The impaired joint causes the first metatarsal bone to become unstable in the frontal and sagittal planes. In this retrospective study we evaluated data of patients with rheumatoid arthritis who underwent Lapidus procedure. We evaluated the role of the instability in a group of patients, focusing mainly on the clinical symptoms and X-ray signs of the instability.

Methods

The study group included 125 patients with rheumatoid arthritis. The indications of the Lapidus procedure were a hallux valgus deformity greater than 15 degrees and varus deformity of the first metatarsal bone with the intermetatarsal angle greater than 15 degrees on anterio-posterior weight-bearing X-ray.

Results

Data of 143 Lapidus procedures of 125 patients with rheumatoid arthritis, who underwent surgery between 2004 and 2010 was evaluated. Signs and symptoms of the first metatarsal bone instability was found in 92 feet (64.3%) in our group. The AOFAS score was 48.6 before and 87.6 six months after the foot reconstruction. Nonunion of the medial cuneometatarsal joint arthrodesis on X-rays occurred in seven feet (4.9%).

Conclusion

The Lapidus procedure provides the possibility to correct the first metatarsal bone varus position and its instability, as well as providing the possibility to achieve a painless foot for walking. We recommend using the procedure as a preventive surgery in poorly symptomatic patients with rheumatoid arthritis in case of the first metatarsal bone hypermobility.

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.

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.