Functional hallux rigidus and the Achilles-calcaneus-plantar system

First ray mobility in hallux rigidus, hallux valgus, and normal feet based on weightbearing computed tomography and three-dimensional analysis: A case-control study

BACKGROUND

Hallux valgus and hallux rigidus are disorders affecting the first ray and are associated with hypermobility of this structure. This study aimed to investigate the three-dimensional mobility of each joint of the first ray between feet with hallux valgus or hallux rigidus and healthy feet using weightbearing and nonweightbearing computed tomography (CT).

METHODS

This case-control study analyzed 17 feet of 11 healthy volunteers (control group), 16 feet of 16 patients with hallux valgus (HV group), and 16 feet of 11 patients with hallux rigidus (HR group). First, nonweightbearing foot CT imaging was performed in the supine position on a loading device with no load applied, with the legs extended and the ankle in the neutral position. Next, a load equivalent to body weight was applied for weightbearing CT imaging. Distal bone displacement relative to the proximal bone was quantified three-dimensionally under both conditions.

RESULTS

In the HV group, the talonavicular joint showed significantly greater eversion (P = 00.011) compared with the control group and significantly greater dorsiflexion (P = 00.027) and eversion (P < 00.01) compared with the HR group. In the medial cuneiform joint, the HV group showed significantly greater eversion (P < 00.01) and abduction (P = 00.011) than the control group. For the first tarsometatarsal joint, the HV group showed significantly greater dorsiflexion (P = 00.014), inversion (P = 00.028), and adduction (P < 00.01) than the control group, and greater inversion (P < 00.01) and adduction (P < 00.01) than the HR group. Dorsiflexion of the first tarsometatarsal joint was significantly greater in the HR group compared with the control group (P = 00.026).

CONCLUSION

Hypermobility of the first ray appears to be three-dimensional: in hallux valgus, it is centered at the first tarsometatarsal joint, while in hallux rigidus it is mainly in the sagittal plane at the first tarsometatarsal joint only. This difference may explain the different deformities ultimately observed in each condition.

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.

Evaluation of Gait Parameters on Subjects with Hallux Limitus Using an Optogait Sensor System: A Case-Control Study

Background and Objetives: The foot is a part of the body's kinetic chain and needs to be efficient during the entire gait cycle. Electronic Sensor Gait analysis is useful and an important tool within the area of podiatry to assess the physical state of patients that helps the comprehensive intervention in situations where the daily activity is limited. The aim of this research is to evaluate if the presence of a hallux limitus (HL) can alter gait space-time parameters and consequently can affect the take-off phase of the gait and the limitation of the range of motion (ROM) of the hallux. Materials and Methods: A case-control study was designed to verify whether there are alterations in the spatiotemporal parameters of the gait cycle between subjects with structural HL compared to the group of subjects with a normal hallux range. A total of n = 138 participants, cases (68 HL subjects) and healthy controls (70 subjects) were studied using an OptoGait LED sensor system to identify gait imbalances using OptoGait photocell gait analysis sensors. Results: Significant differences were found between the two groups with respect to stride length, gait cycle duration in seconds (for both feet) and for total stride and load response (p < 0.05). Conclusions: The limitation of the Hallux ROM may alter the normal gait patterns measured with an Optogait system. The early identification and treatment of gait disturbances due to HL are important to achieve normal gait physical activity to maintain a healthy lifestyle.

Three-Dimensional Analysis of the Windlass Mechanism Using Weightbearing Computed Tomography in Healthy Volunteers

BACKGROUND

The windlass mechanism (WM) increases the longitudinal arch of the foot via tension of the plantar aponeurosis during dorsiflexion of the metatarsophalangeal (MTP) joint. The purpose of this study was to perform a 3-dimensional evaluation of the displacement of each joint and the height of the navicular during dorsiflexion of the first MTP joint by using weightbearing computed tomography (CT).

METHODS

Participants were 6 men and 8 women with 23 healthy feet. CT of the foot with a load equivalent to the participant's body weight was performed. The first MTP joint was in the neutral position and dorsiflexed 30 degrees. Between the conditions, we measured the (1) rotation of each bone, (2) rotation of the distal bone with respect to the proximal bone at each joint, and (3) height of the navicular.

RESULTS

With respect to the tibia, the calcaneus was at 0.8 ± 0.7 degrees dorsiflexion and 1.4 ± 0.9 degrees inversion, while the talus was at 2.0 ± 1.2 degrees dorsiflexion and 0.1 ± 0.8 degrees eversion. The navicular was at 1.3 ± 1.2 degrees dorsiflexion and 3.2 ± 2.1 degrees inversion, whereas the medial cuneiform was at 0.3 ± 0.6 degrees plantarflexion and 1.3 ± 1.1 degrees inversion. At the talonavicular joint, the navicular was at 0.7 ± 1.3 degrees plantarflexion, whereas at the cuneonavicular joint, the medial cuneiform bone was at 1.4 ± 1.4 degrees plantarflexion. The height of the navicular increased by 1.1 ± 0.6 mm.

CONCLUSION

We 3-dimensionally confirmed the dynamics of WM and found that the calcaneus, navicular, and medial cuneiform moved in all 3 planes. The results suggest that the cuneonavicular joint has the greatest movement among the joints. We believe that these findings will help to elucidate the pathogenesis of WM-related diseases and lead to advances in treatments for pathologies involving the longitudinal arch.

LEVEL OF EVIDENCE

Level IV, case series.

Assessment and Management of Atraumatic First Metatarsophalangeal Joint Pain

Nontraumatic pain in the first metatarsophalangeal joint is frequent and can be debilitating. The metatarsophalangeal joint complex comprises four articulating surfaces including the first metatarsal, the proximal phalanx, and tibial and fibular sesamoids, which are all contained within a synovial capsule. The most common causes of pain are hallux valgus and hallux rigidus. However, other diagnoses, such as functional hallux limitus, sesamoiditis, gout, and inflammatory autoimmune arthritis, need to be considered as well. A systematic approach is key to accurately diagnose the source of pain, which can sometimes be the result of more than one condition. The most important clinical information to obtain is a focused history, meticulous clinical examination based on understanding the precise anatomy and biomechanics of the first metatarsophalangeal joint, and analysis of the relevant imaging. Each pathology has a different treatment algorithm, as such, understanding the pathoanatomy and biomechanics is important in forming an effective treatment plan.

Morton’s Extension on Hallux Rigidus Pathology

Study design, case-control study: Background, Morton’s extension (ME) is a kind of orthotic that has been used as a conservative treatment of painful hallux rigidus (HR) osteoarthritis, but only their effects on first metatarsophalangeal joint (MPJ) mobility and position in healthy subjects have been studied, but not on its applied pulled tension forces neither in subjects with HR. Objectives: This study sought to understand how ME’s orthotics with three different thicknesses could influence the kinematic first MPJ by measuring hallux dorsiflexion using Jack’s test and a digital algometer with a rigid strip anchored to the iron hook’s extremity and comparing subjects with healthy first MPJ mobility to those with HR. We aimed to clarify whether tension values were different between healthy and HR subjects. Methods: Fifty-eight subjects were selected, of whom thirty were included in the case group according to HR criteria and twenty-eight were included in the control group. A digital algometer (FPX®® 25, Wagner Instruments®®, Greenwich, CT, USA) was used to assess the pulled tension values (kgf) of the first MPJ during Jack’s test. Results: The pulled tension values were highly reliable (ICC > 0.963). There were no statistically significant differences between the pulled tension values for the different ME conditions in the case (p = 0.969) or control (p = 0.718) groups. However, as it’s expected, there were statistically significant differences comparing all pulled tension values between case and control group subjects (p < 0.001). Conclusions: Different ME’s thicknesses had no influence on the pulled effort applied during the dorsiflexion Jack’s test between the healthy and HR groups; therefore, it can be prescribed without joint-care danger. In addition, it is proven that there is greater resistance to performing Jack’s test in the HR group than in the healthy group, regardless of ME’s orthotics. Furthermore, it is shown that the digital algometer device is a valid tool to detect the first MPJ restriction and is more reliable than other tests.

Complications of Hallux Rigidus Surgery

Hallux rigidus can be treated with a variety of surgical procedures, including joint preserving techniques, arthrodesis, and arthroplasty. The most commonly reported complications for joint preserving techniques consist of progression of arthritis, continued pain, and transfer metatarsalgia. Although good outcomes have been reported for arthrodesis overall, careful attention must be paid to technique and positioning of the toe to avoid nonunion or malunion. Arthroplasty preserves motion but in the case of failure can present the additional challenge of bone loss. In these scenarios, the authors recommend distraction bone block arthrodesis with structural autograft.

Effects of Novel Inverted Rocker Orthoses for First Metatarsophalangeal Joint on Gastrocnemius Muscle Electromyographic Activity during Running: A Cross-Sectional Pilot Study

BACKGROUND

The mobility of the first metatarsophalangeal joint (I MPTJ) has been related to the proper windlass mechanism and the triceps surae during the heel-off phase of running gait; the orthopedic treatment of the I MPTJ restriction has been made with typical Morton extension orthoses (TMEO). Nowadays it is unclear what effects TMEO or the novel inverted rocker orthoses (NIRO) have on the EMG activity of triceps surae during running.

OBJECTIVE

To compare the TMEO effects versus NIRO on EMG triceps surae on medialis and lateralis gastrocnemius activity during running.

STUDY DESIGN

A cross-sectional pilot study.

METHODS

21 healthy, recreational runners were enrolled in the present research (mean age 31.41 ± 4.33) to run on a treadmill at 9 km/h using aleatory NIRO of 6 mm, NIRO of 8 mm, TMEO of 6 mm, TMEO of 8 mm, and sports shoes only (SO), while the muscular EMG of medial and lateral gastrocnemius activity during 30 s was recorded. Statistical intraclass correlation coefficient (ICC) to test reliability was calculated and the Wilcoxon test of all five different situations were tested.

RESULTS

The reliability of values was almost perfect. Data showed that the gastrocnemius lateralis increased its EMG activity between SO vs. NIRO-8 mm (22.27 ± 2.51 vs. 25.96 ± 4.68 mV, p < 0.05) and SO vs. TMEO-6mm (22.27 ± 2.51 vs. 24.72 ± 5.08 mV, p < 0.05). Regarding gastrocnemius medialis, values showed an EMG notable increase in activity between SO vs. NIRO-6mm (22.93 ± 2.1 vs. 26.44 ± 3.63, p < 0.001), vs. NIRO-8mm (28.89 ± 3.6, p < 0.001), and vs. TMEO-6mm (25.12 ± 3.51, p < 0.05).

CONCLUSIONS

Both TMEO and NIRO have shown an increased EMG of the lateralis and medialis gastrocnemius muscles activity during a full running cycle gait. Clinicians should take into account the present evidence when they want to treat I MTPJ restriction with orthoses, and consider the inherent triceps surae muscular cost relative to running economy.

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.

Mechanical Basis of Metatarsalgia

The 3-rocker mechanism of gait provides a framework to understand why patients have mechanical metatarsal pain and to differentiate between the various types of metatarsalgia. Clinical examination of the patient together with radiological findings allows identification of the type of metatarsalgia and the pathomechanics involved, and the planning of surgical treatment. Second-rocker/nonpropulsive metatarsalgia is related with an abnormal inclination of a metatarsal in the sagittal plane, either anatomic or functional (equinism). Third-rocker/propulsive metatarsalgia is related to an abnormal length of a certain metatarsal with respect to the neighboring metatarsals in the transverse plane.

The Role of Plantar Fascia Tightness in Hallux Limitus: A Biomechanical Analysis

Restriction of greater toe dorsiflexion without degeneration of the first metatarsophalangeal joint is defined as hallux limitus. We assume that in hallux limitus the limitation of greater toe dorsiflexion takes place in the terminal stance phase because of massive tightening of the calf and plantar structures. The current study investigated the role of a tight plantar fascial structure in impairing dorsiflexion of the greater toe. For the purpose of the study, 7 lower limbs from Thiel-fixated human cadavers were evaluated. To simulate double-limb standing stance, the tibia and fibula were mounted on a materials testing machine and constantly loaded with 350N. Additionally, the tendons of the specimens were loaded using a custom-made system. The plantar fascia was fixed to a clamp and tensioned using a threaded bar. Four different tensile forces were then applied to the plantar fascia (approximately 100, 200, 300, and 350 N) and the extension of the first toe was measured. The results show a significant positive correlation between the decrease in extension of the hallux and the tension applied to the plantar fascia reaching a maximum mean decrease of 4.2° (117% compared with the untightened situation) for an applied tension of 364N.

Predictors of Diabetic Foot Reulceration beneath the Hallux

AIMS

To evaluate the factors that predict reulceration beneath the hallux in people with a history of diabetic foot ulceration.

METHODS

A prospective study conducted between January 2012 and December 2014 was performed in a diabetic foot unit to assess the risk factors associated with hallux reulceration. Sixty patients with diabetic neuropathy and a history of previous ulcer were consecutively included. Sociodemographic factors and comorbidities plus the biomechanical and radiographic factors were obtained. Follow-up on participants was conducted every month, and they wore offloading therapeutic footwear and custom-made insoles. Hallux reulceration during the follow-up period was assessed as the main outcome measure in the study.

RESULTS

Patients were followed up during 29 (14.2-64.4) months. Twenty-nine patients (52%) developed a new ulceration: 9 patients (31%) in the hallux and 20 (69%) in other locations. Functional hallux limitus (p = 0.005, 95% CI (2.097-73.128), HR 12.384) and increased body mass index (p = 0.044, 95% CI (1.003-1.272), HR 1.129) were associated with the hallux ulceration-free survival time in the multivariate Cox model.

CONCLUSIONS

Obesity and the presence of functional hallux limitus increase the probability of developing hallux reulceration in patients with diabetic neuropathy and a history of ulcers.

Weightbearing CT Scan Assessment of Foot Alignment in Patients With Hallux Rigidus

BACKGROUND

An association between hallux rigidus and metatarsus primus elevatus (MPE) has been suggested, although there remains no general consensus about the nature of this relationship. Past studies were limited due to inaccuracies of assessing MPE on 2-dimensional radiographs. The aims of this study were to (1) assess and compare foot alignment in patients with and without hallux rigidus using 3-dimensional (3D) reconstructions from weightbearing computed tomography (CT) and (2) assess intraobserver and interobserver reliability of these measurements.

METHODS

A prospective study was performed in 50 consecutive patients with symptomatic hallux rigidus and 50 control patients who underwent a weightbearing CT. Two investigators measured first and second metatarsal declination angles, first and second metatarsal lengths, first to second intermetatarsal angle (IMA), hallux valgus angle (HVA), and foot width on 3D CT reconstructions. Measurements were repeated after 1 month. Student t tests were performed to compare hallux rigidus and control groups. Intraclass and interclass correlation coefficients were calculated to evaluate reliability.

RESULTS

The first to second metatarsal declination ratio was less in patients with hallux rigidus (mean, 0.81) than controls (mean, 0.92; P < .001). Patients with Coughlin and Shurnas grade 3 and 4 hallux rigidus had greater first metatarsal declination than patients with grade 1 and 2 hallux rigidus. Last, IMA was higher (mean, 13 degrees) but HVA was lower (mean, 11 degrees) in patients with hallux rigidus than controls (IMA mean, 12 degrees; HVA mean, 15 degrees; P = .04). Intraobserver (ICC1,1 ≥ 0.93) and interobserver (ICC3,1 ≥ 0.85) reliability were good to excellent for all measured parameters.

CONCLUSIONS

Patients with hallux rigidus had MPE. Patients with grade 3 and 4 hallux rigidus had more MPE than patients with grade 1 and 2 hallux rigidus. There was no clear correlation between hallux rigidus and bunions. Finally, weightbearing CT proved to be a reliable method of assessing all measured parameters.

LEVEL OF EVIDENCE

II, prospective comparative series.

Measuring Joint Flexibility in Hallux Rigidus Using a Novel Flexibility Jig

BACKGROUND

The flexibility of the first metatarsophalangeal (MTP) joint in patients with hallux rigidus (HR) has not been studied. Compared to measuring range of motion alone, measures of joint flexibility provide additional information that may prove useful in the assessment of HR. The purpose of this study was to assess the flexibility of the hallux MTP joint in patients with HR compared to controls using a novel flexibility device.

METHODS

Fifteen patients with Coughlin stage II or III HR and 20 healthy controls were recruited prospectively. Using a custom flexibility jig, each of 2 raters performed a series of seated and standing tests on each subject. Dorsiflexion angle and applied torque were plotted against each other to generate 5 different parameters of flexibility. Differences between (1) HR patients and controls and (2) the sitting and standing testing positions were assessed with t tests. Intrarater test-retest reliability, remove-replace reliability, and interrater reliability were assessed with intraclass correlation coefficients (ICCs).

RESULTS

Patients in the HR group were older than patients in the control group ( P < .001) and had lower maximum dorsiflexion ( P < .001). HR patients were less flexible as measured by 3 of the 5 flexibility parameters: early flexibility (first 25% of motion; P = .027), laxity angle ( P < .001), and torque angle ( P = .002). After controlling for age, only laxity angle differed significantly between HR patients and controls ( P < .001). Generally, patients were more flexible when seated compared to standing, with this effect being more marked in HR patients. All parameters had good or excellent intra- and interrater reliability (ICC ≥ 0.60).

CONCLUSIONS

Hallux MTP joint flexibility was reliably assessed in HR patients using a flexibility device. Patients with HR had decreased flexibility of the hallux MTP joint compared to control patients.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

3D characterisation of the dynamics of foot joints of adults during walking. Gait pattern identification

A detailed description of the kinematics and kinetics of the ankle, midtarsal and metatarsophalangeal joints of the feet of a healthy adult male population during barefoot walking is provided. Plots of the angles and moments in each plane during the stance phase are reported, along with the mean and standard deviation values of 87 different parameters that characterise the 3D dynamics of the foot joints. These parameters were used to check for similarities between subjects through a hierarchical analysis that allowed three different gait patterns to be identified, most of the differences corresponding to the frontal and transverse planes.

Equinus and Lengthening Techniques

Equinus is linked to most lower extremity biomechanically related disorders. Defining equinus as ankle joint dorsiflexion less than 5° of dorsiflexion with the knee extended is the basis for evaluation and management of the deformity. Consistent evaluation methodology using a goniometer with the subtalar joint in neutral position and midtarsal joint supinated while dorsiflexing the ankle with knee extended provides a consistent clinical examination. For equinus deformity with an associated disorder, comprehensive treatment mandates treatment of the equinus deformity. Surgical treatment of equinus offers multiple procedures but the Baumann gastrocnemius recession is preferred based on deformity correction without weakness.

The Split Second Effect: The Mechanism of How Equinus Can Damage the Human Foot and Ankle

We are currently in the process of discovering that many, if not the majority, of the non-traumatic acquired adult foot and ankle problems are caused by a singular etiology: non-neuromuscular equinus or the isolated gastrocnemius contracture. There is no question that this biomechanical association exists and in time much more will be uncovered. There are three basic questions that must be answered: why would our calves tighten as we normally age, how does a tight calf, or equinus, actually cause problems remotely in the foot and ankle, and how do the forces produced by equinus cause so many seemingly unrelated pathologies in the foot and ankle? The purpose of this paper is to address the second question: how does a tight calf mechanically cause problems remotely in the foot and ankle? There has been little evidence in the literature addressing the biomechanical mechanisms by which equinus creates damaging forces upon the foot and ankle, and as a result, a precise, convincing mechanism is still lacking. Thus, the mere concept that equinus has anything to do with foot pathology is generally unknown or disregarded. The split second effect, described here, defines exactly how the silent equinus contracture creates incremental and significant damage and injury to the human foot and ankle resulting in a wide variety of pathological conditions. The split second effect is a dissenting theory based on 30 years of clinical and academic orthopedic foot and ankle experience, keen clinical observation along the way, and review of the developing literature, culminating in examination of many hours of slow motion video of normal and abnormal human gait. To my knowledge, no one has ever described the mechanism in detail this precise.

Accurate Measurement of First Metatarsophalangeal Range of Motion in Patients With Hallux Rigidus

BACKGROUND

The reliability of range of motion (ROM) measurements has not been established for the hallux metatarsophalangeal (MTP) joint in patients with hallux rigidus. The aim of the present study was to prospectively assess the clinical versus radiographic difference in ROM of the arthritic hallux MTP joint.

METHOD

One hundred consecutive patients who presented with any grade of hallux rigidus were included in this prospective study to determine the hallux MTP range of motion. Clinical range of motion using a goniometer and radiographic range of motion on dynamic x-rays was recorded.

RESULTS

The mean difference between clinical and radiographic dorsiflexion was 13 degrees (P < .001). For all measurements, clinical dorsiflexion was equal to or less than radiographically measured dorsiflexion. The difference was significantly greater in patients with a clinical dorsiflexion of less than 30 degrees than in patients with 30 degrees or more. Radiographic measurement of hallux dorsiflexion had an excellent intra- and interobserver reliability.

CONCLUSION

We describe a reliable, reproducible, and straightforward method of measuring hallux MTP ROM that improved upon measuring clinical ROM.

LEVEL OF EVIDENCE

Level II, prospective comparative study.