Muscle moment arm is a property that associates muscle force with joint moment and is crucial to biomechanical analysis. In musculoskeletal simulations, the accuracy of moment arm is as important as that of muscle force, and calibrating moment arms in a musculoskeletal model requires data from anatomical measurements. Nonetheless, such data are elusive, and the complex relation between moment arm and joint angle can be unclear. Using common techniques in systematic review, we collected a total of 300 moment arm datasets from literature and visualized the muscle moment arm-joint angle relations in the human hip, knee, and ankle. The findings contribute to the analysis of musculoskeletal mechanics and providing reference regarding the experimental design for future moment arm measurements.

The first metatarsophalangeal (MTP) joint plays a crucial role in foot biomechanics, particularly in weight-bearing activities such as walking and running. It is frequently affected by conditions like hallux valgus (HV) and hallux rigidus, with HV impacting approximately 23%-35% of the population. This narrative review explores the embryology, anatomy, and biomechanics of the first MTP joint (MTPJ), highlighting its significance in maintaining foot stability and function. A comprehensive literature search was conducted using PubMed, Scopus, and Google Scholar, analyzing 50 relevant studies, including 12 clinical trials. The joint's complex structure and mechanical demands make it susceptible to degenerative and structural disorders. Studies indicate that 25%-40% of individuals with HV experience significant pain and functional impairment, affecting mobility and quality of life. Biomechanical stress, abnormal gait patterns, and joint instability contribute to disease progression. Understanding the anatomical and biomechanical properties of the first MTPJ is essential for improving diagnostic and therapeutic approaches. Emerging surgical techniques, such as osteotomy and joint resurfacing, show promise in reducing recurrence rates and enhancing long-term outcomes. Further research is needed to refine minimally invasive interventions and optimize treatment strategies for first MTPJ disorders.

Injuries to the first metatarsophalangeal joint are often missed and not adequately treated, resulting in secondary deformities and degenerative arthritis. The particular anatomy of the joint puts mainly soft tissue structures at risk, which is why conditions such as turf toe injury and valgus or varus deformities can occur. Because the sesamoid bones are receiving high pressures, fractures should be considered. Many conditions can be treated conservatively by offloading, immobilization, or taping. Surgical options for high instability, dislocated fractures, or advanced cartilage damage should be recommended.

The paper deals with the torques of external muscles acting on the upper ankle joint under weight-bearing conditions and their importance in diagnosing and treating the human foot. Experimental data were collected and calculations were performed. Based on the experiments with the biomechanical model of the foot and upper ankle joint, it was shown how the changes in the force arms of the external muscles of the foot under weight-bearing conditions, change the torque. The real values of muscle forces and torques of the external muscles of the foot were calculated. Taking into account the distance of the lines of muscle action from the axis of rotation of the upper ankle joint the rotational force of the muscles was calculated. The influence of changing the force arm on the rotational efficiency of the muscle balancing the moment of gravity was shown. Knowledge of muscle torque under weight-bearing conditions is crucial for correctly assessing foot biomechanics. It has been shown that torque (gravitational and muscular), not pure force, is crucial when assessing the rotational capacity of the analyzed joint. A change in the approach to diagnostics and treating paresis or weakness of extrinsic foot muscles was proposed through the manipulation of the distance of their action line from the axis of joint rotation.

First metatarsophalangeal joint sprains or turf toe (TT) injuries occur secondary to forceful hyperextension of the great toe. TT injuries are common among athletes, especially those participating in football, soccer, basketball, dancing, and wrestling. This review summarizes the current treatment modalities, rehabilitation protocols, and return-to-play criteria, as well as performance outcomes of patients who have sustained TT injuries.

Less than 2% of TT injuries require surgery, but those that do are typically grade III injuries with damage to the MTP joint, evidence of bony injury, or severe instability. Rehabilitation protocols following non-operative management consist of 3 phases lasting up to 10 weeks, whereas protocols following operative management consist of 4 phases lasting up 20 weeks. Athletes with low-grade injuries typically achieve their prior level of performance. However, among athletes with higher grade injuries, treated both non-operatively and operatively, about 70% are expected to maintain their level of performance. The treatment protocol, return-to-play criteria, and overall performance outcomes for TT injuries depend on the severity and classification of the initial sprain. For grade I injuries, players may return to play once they experience minimal to no pain with normal weightbearing, traditionally after 3-5 days. For grade II injuries, or partial tears, players typically lose 2-4 weeks of play and may need additional support with taping when returning to play. For grade III injuries, or complete disruption of the plantar plate, athletes lose 4-6 weeks or more depending upon treatment strategy.

To maximize effects of dorsal leaf ankle foot orthoses (AFOs) on gait in people with bilateral plantarflexor weakness, the AFO properties should be matched to the individual. However, how AFO properties interact regarding their effect on gait function is unknown. We studied the interaction of AFO bending stiffness with neutral angle and footplate stiffness on the effect of bending stiffness on walking energy cost, gait kinematics and kinetics in people with plantarflexor weakness by employing predictive simulations. Our simulation framework consisted of a planar 11 degrees of freedom model, containing 11 muscles activated by a reflex-based neuromuscular controller. The controller was optimized by a comprehensive cost function, predominantly minimizing walking energy cost. The AFO bending and footplate stiffness were modelled as torsional springs around the ankle and metatarsal joint. The neutral angle of the AFO was defined as the angle in the sagittal plane at which the moment of the ankle torsional spring was zero. Simulations without AFO and with AFO for 9 bending stiffnesses (0-14 Nm/degree), 3 neutral angles (0-3-6 degrees dorsiflexion) and 3 footplate stiffnesses (0-0.5-2.0 Nm/degree) were performed. When changing neutral angle towards dorsiflexion, a higher AFO bending stiffness minimized energy cost of walking and normalized joint kinematics and kinetics. Footplate stiffness mainly affected MTP joint kinematics and kinetics, while no systematic and only marginal effects on energy cost were found. In conclusion, the interaction of the AFO bending stiffness and neutral angle in bilateral plantarflexor weakness, suggests that these should both be considered together when matching AFO properties to the individual patient.

Dancers are highly vulnerable to injuries due to high dynamic overload, extreme positions and motions, and excessive use. Increased load at the forefoot with jumping and high-impact lands can cause sesamoiditis and stress fractures of the metatarsals. Significant plantarflexion can lead to posterior joint impingement and flexor hallucis longus tendonitis, whereas forced dorsiflexion can cause anterior joint impingement. Most pathologies can be diagnosed on physical examination and various imaging modalities. Treatment should be tailored to the dancers' needs and should begin with a course of conservative therapy with immobilization, physical therapy, and activity cessation.

Capsuloligamentous injury of the first metatarsophalangeal (MTP) joint (eponymously called "turf toe") mostly occurs in athletes and involves acute trauma, whereas tears of the lesser MTP joint plantar plate typically are an attritional-degenerative condition. This article reviews the anatomy, pathophysiology, mechanism and patterns of injury, grading and classification of injury, imaging appearances (pre- and postoperative), and management of first MTP joint capsuloligamentous injuries and lesser MTP joint plantar plate tears. These two distinct pathologies are discussed in separate sections.

There have been a dozen case reports of congenital absence of pedal sesamoid absence. We present the first documented case of congenital bilateral absence of tibial sesamoids with use of magnetic resonance imaging to identify a naturally occurring compensatory aberration of the flexor hallucis brevis. The right foot had bifurcation of the flexor hallucis brevis with one slip blending into the abductor hallucis tendon and capsule and the other slip traversing laterally and attaching to lateral flexor hallucis brevis tendon and fibular sesamoid. On the left foot, the entire flexor hallucis brevis traversed laterally and attached onto the fibular sesamoid and lateral flexor hallucis brevis. The present findings of this patient's anatomical variation could help provide valuable information to prevent known deformities that are the sequalae of a tibial sesamoidectomy.

Lateral hallucal sesamoidectomy is an infrequently performed procedure indicated for patients with sesamoid pathology failing conservative treatment. Concerns exists regarding patient satisfaction, plantar scar pain, hallux malalignment and metatarsophalangeal joint (MTPJ) movement restriction following sesamoidectomy. This study aims to assess patient satisfaction after lateral hallucal sesamoidectomy via the plantar approach.

In this retropective study with prospective follow-up, all patients who underwent lateral hallucal sesamoidectomy between January 2004 and December 2017 were reviewed. Twelve patients (14ft.) were available for final assessment. Outcome measures were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) clinical rating scale and the Self-Reported Foot and Ankle questionnaire (SEFAS). Patients were assessed clinically and radiologically. The average postoperative follow-up was 111.5 months (range 28-177 months).

All patients reported excellent outcome scores with a mean SEFAS score of 46.08 (range 43-48) and a mean AOFAS score of 92.33 (range 78-100) at final follow-up. All twelve patients reported their outcome as being excellent. No malalignment was noted clinically, however, three patients had a noticeable increase in the gap between the hallux and second toe when compared to the contralateral side. Range of motion at the MTPJ was preserved with a mean dorsiflexion of 80.83° (range 70-90°) and a mean plantarflexion was 25.83° (range 0-30°). None of the patients experienced any pain, discomfort or irritation related to the plantar scar. One patient developed neuroma like symptoms in the first web space.

Lateral hallucal sesamoidectomy via a plantar approach is an effective and reliable treatment option as demonstrated by the high levels of patient satisfaction, preservation of function, excellent PROM scores and limited complications in this study.

Level 4.

Background Pathologic conditions of the sesamoids can be a source of disabling pain for patients, particularly during toe-off. Some underlying causes include osteonecrosis, inflammation, arthritis, and fracture. Nonoperative treatment is the initial standard of care, and has demonstrated satisfactory outcomes overall; however, operative management may be indicated in cases of pain refractory to conservative management. Sesamoidectomy is an uncommon procedure with risk of potential complications, but may be warranted in select cases of failed nonoperative treatment. Methods A retrospective chart review was conducted at one institution from 2009 to 2018. Twelve patients diagnosed with fibular sesamoiditis were treated with sesamoidectomy. Baseline patient demographics as well as postoperative outcomes were recorded. Results All 12 patients underwent fibular sesamoidectomy using the plantar approach following which their symptom (pain) resolved. Average follow-up for this cohort was 35 months. Of the sample, two patients experienced transient neuritis, one patient developed a superficial infection, and one had painful postoperative scarring. Hallux varus deformity was not observed in any patients. Conclusion Fibular sesamoidectomy may be a safe, viable procedure for patients with sesamoiditis who fail conservative measures.

Turf toe injuries can be a disabling if not recognized and treated early. A high index of suspicion, based on the mechanism of injury and appropriate imaging, helps in the timely diagnosis. These injuries are frequently known to occur on artificial playing surfaces, because of the increased traction at the shoe-surface interface. Stress and instability testing are key components to assess the need for surgical intervention. Accurate timely diagnosis and treatment can allow full return to physical activities for most athletes, back to their pre-injury level.

Studies have shown that sesamoidectomy provides good clinical outcomes; however, concern exists regarding complications occurring after resection of 1 or both sesamoid bones. The purpose of the present systematic review was to evaluate the current evidence on sesamoidectomy for the treatment of hallux sesamoid disorders. A systematic search of the MEDLINE, Embase, and Cochrane Library databases was performed during October 2017. The included studies were evaluated for the level of evidence and quality of evidence using the Coleman Methodology Score. Variable reporting outcomes data, clinical outcomes, and percentage of patients returning to sports at their previous level were evaluated. Ten studies, totaling 196 feet, were included. The weighted mean patient age was 36.6 ± 11.0 years, and the weighted mean follow-up duration was 45.1 ± 19.3 months. The mean visual analog scale score improved from 6.5 ± 0.3 to 1.2 ± 0.5. The mean postoperative American Orthopaedic Foot and Ankle Society ankle-hindfoot scale score was 92.7 ± 2.7. Six studies demonstrated that 94.4% of patients returned to sports, with 90.0% returning to their previous level, at a mean of 11.8 ± 1.8 weeks. The mean hallux valgus angle increased from 13.1° ± 2.1° preoperatively to 14.8° ± 3.7° postoperatively (p = .470), and the mean intermetatarsal angle increased from 8.7° ± 0.8° to 9.7° ± 0.8° (p = .180). Overall complication rate was 22.5% and the revision rate was 3.0%. The present systematic review has demonstrated that sesamoidectomy for hallux sesamoids disorders yields good clinical outcomes and a high rate of return to sports in the short term, albeit with a high complication rate of 22.5%.

Lesser metatarsal sesamoids are one of the most common accessory bones of the foot and are most commonly seen at the fifth metatarsophalangeal joint. They are rarely seen in other metatarsophalangeal joints. In the literature, there are reports of solitary accessory sesamoid bones seen at lesser metatarsophalangeal joints. We report the case of a 68-year-old woman with lesser metatarsal sesamoids accompanying all of the metatarsophalangeal joints.

Injuries to the foot and ankle are commonly encountered, especially among athletes, and can lead to morbidity if not managed appropriately. Health care professionals must have a firm understanding of injury anatomy, diagnoses, and management. This article provides a review of lateral talus process fractures, os trigonum injuries, Lisfranc injuries, turf toe, navicular stress fractures, and syndesmotic injuries.

Injuries to the great toe are common in athletes. While most are managed nonoperatively and allow return to sports activity, some great toe injuries are highly problematic and can impact function. The purpose of this review is to highlight several specific injuries and disease processes involving the hallux and to detail current recommendations and management options in order to help raise suspicion for injuries that can result in long-term dysfunction.

Toe injuries have been found to represent nearly 10% of injuries presenting to fracture clinics. While most injuries can be treated nonsurgically, there are a number of specific injuries that require a high index of suspicion, careful management, and in some cases, surgical intervention. Injuries detailed in this review include turf toe, traumatic bunion, and hallux and sesamoid fractures. Additional pathologies that are covered include sesamoiditis and sesamoid avascular necrosis as well as hallux rigidus. Appropriate workup and current treatment recommendations are discussed. Injuries to the hallux can result in long-term pain and disability if not properly diagnosed and treated. A high index of suspicion is required.

Stress fractures are common overuse injuries in athletes. They occur during periods of increased training without adequate rest, disrupting normal bone reparative mechanisms. There are a host of intrinsic and extrinsic factors, including biochemical and biomechanical, that put athletes at risk. In most stress fractures, the diagnosis is primarily clinical, with imaging indicated at times, and management focused on symptom-free relative rest with advancement of activity as tolerated. Overall, stress fractures in athletes have an excellent prognosis for return to sport, with little risk of complication. There is a subset of injuries that have a greater risk of fracture progression, delayed healing, and nonunion and are generally more challenging to treat with nonoperative care. Specific locations of high-risk stress fracture include the femoral neck (tension side), patella, anterior tibia, medial malleolus, talus, tarsal navicular, proximal fifth metatarsal, and great toe sesamoids. These sites share a characteristic region of high tensile load and low blood flow. High-risk stress fractures require a more aggressive approach to evaluation, with imaging often necessary, to confirm early and accurate diagnosis and initiate immediate treatment. Treatment consists of nonweight-bearing immobilization, often with a prolonged period away from sport, and a more methodic and careful reintroduction to athletic activity. These stress fractures may require surgical intervention. A high index of suspicion is essential to avoid delayed diagnosis and optimize outcomes in this subset of stress fractures.

Inverse dynamics joint kinetics are often used to infer contributions from underlying groups of muscle-tendon units (MTUs). However, such interpretations are confounded by multiarticular (multi-joint) musculature, which can cause inverse dynamics to over- or under-estimate net MTU power. Misestimation of MTU power could lead to incorrect scientific conclusions, or to empirical estimates that misguide musculoskeletal simulations, assistive device designs, or clinical interventions. The objective of this study was to investigate the degree to which ankle joint power overestimates net plantarflexor MTU power during the Push-off phase of walking, due to the behavior of the flexor digitorum and hallucis longus (FDHL)-multiarticular MTUs crossing the ankle and metatarsophalangeal (toe) joints.

We performed a gait analysis study on six healthy participants, recording ground reaction forces, kinematics, and electromyography (EMG). Empirical data were input into an EMG-driven musculoskeletal model to estimate ankle power. This model enabled us to parse contributions from mono- and multi-articular MTUs, and required only one scaling and one time delay factor for each subject and speed, which were solved for based on empirical data. Net plantarflexing MTU power was computed by the model and quantitatively compared to inverse dynamics ankle power.

The EMG-driven model was able to reproduce inverse dynamics ankle power across a range of gait speeds (R2 ≥ 0.97), while also providing MTU-specific power estimates. We found that FDHL dynamics caused ankle power to slightly overestimate net plantarflexor MTU power, but only by ~2-7%.

During Push-off, FDHL MTU dynamics do not substantially confound the inference of net plantarflexor MTU power from inverse dynamics ankle power. However, other methodological limitations may cause inverse dynamics to overestimate net MTU power; for instance, due to rigid-body foot assumptions. Moving forward, the EMG-driven modeling approach presented could be applied to understand other tasks or larger multiarticular MTUs.

A turf toe injury encompasses a wide spectrum of traumatic problems that occur to the first metatarsophalangeal joint. Most of these injuries are mild and respond well to nonoperative management. However, more severe injuries may require surgical management, including presence of diastasis or retraction of sesamoids, vertical instability, traumatic hallux valgus deformity, chondral injury, loose body, and failed conservative treatment.

To present 3 cases of plantar-plate rupture and turf-toe injury in contact athletes at 1 university and to discuss appropriate diagnosis and treatment algorithms for each case.

Turf toe is a common injury in athletes participating in outdoor cutting sports. However, it has been used as an umbrella term to describe many different injuries of the great toe. In some cases, the injury can be so severe that the plantar plate and sesamoid apparatus may be ruptured. These patients may be better managed with surgery than with traditional nonoperative interventions.

Turf toe, plantar-plate disruption, sesamoid fracture.

For stable injuries in which the plantar plate is not completely disrupted, nonoperative treatment with casting or a stiff-soled shoe, gradual weight bearing, and rehabilitation is the best practice. Unstable injuries require surgical intervention and plantar-plate repair.

Turf toe and injury to the first metatarsophalangeal joint are relatively common injuries in athletes, but few researchers have detailed the operative and nonoperative treatments of plantar-plate disruption in these patients. We examine 3 cases that occurred over 4 seasons on a collegiate football team.

Turf toe represents a wide array of pathologic conditions involving the first metatarsophalangeal joint. Stress and instability testing are key components to assess in determining whether surgical intervention is warranted to restore optimal function. Stiffer-soled shoes or shoes with steel-plate insertions may help to prevent these injuries and are useful tools for protection during the rehabilitation period.

The first metatarsophalangeal (MTP) joint complex is a critical weight-bearing structure important to biomechanics. An acute dorsiflexion injury, named "turf toe," is common among American football and soccer players. "Sesamoiditis" is a name often given for pain arising from the hallux sesamoids in the absence of acute trauma, and may result from a variety of causes. The first MTP joint complex can also be affected by degenerative or inflammatory arthritis, infarct, and infection. This review article will cover the anatomy and biomechanics of the first MTP joint complex, its patterns of injury and pathology, imaging techniques, and management.

First ray function and hallux misalignment after isolated tibial sesamoidectomy have been topics of debate. Although sesamoidectomy has been proved to be effective in the relief of sesamoid pain, many foot and ankle surgeons remain hesitant to perform the procedure fearing a possible joint perturbation. To our knowledge, the present study is the first to evaluate both laboratory and clinical evidence of the association between isolated tibial sesamoidectomy and hallux abducto valgus deformity. The bench study consisted of 10 cadaveric limbs that were dissected and prepared for testing. Controlled valgus loads were applied before and after tibial sesamoidectomy. No significant difference was found in the joint position after sesamoidectomy in both the rectus (p = .36) and the dorsiflexed (p = .062) positions. The clinical evaluation consisted of a retrospective cohort of 5 females; all of whom underwent isolated tibial sesamoidectomy. The pre- and postoperative radiographs and self-reported pain scores (visual analog scale) were compared. None of the patients developed a postoperative hallux abducto valgus deformity. Neither the hallux abductus angle (p = .180) nor the intermetatarsal angle 1-2 (p = .180) changed significantly in the postoperative setting. The visual analog scale pain scores changed from a mean of 6.8 to 1, a significant difference (p = .042). Based on our observations and clinical experience, we believe that isolated tibial sesamoidectomy does not have a significant effect on the position of the first metatarsophalangeal joint when meticulous surgical technique is used to excise the sesamoid. Isolated tibial sesamoidectomy can provide substantial pain relief and appears to be a safe treatment for a variety of conditions affecting the tibial sesamoid.

The Weil oblique distal metatarsal osteotomy is regularly used in the treatment of primary metatarsalgia. The most frequent complication is the floating toe, which occurs in up to 36% of postoperative follow-up. The theory of reducing the plantar flexor mechanism tension associated with the retraction of the dorsal structures during the healing process of the surgical procedure may explain this negative evolution.

This study aimed at assessing the effectiveness of the Tucade dorsal thermoplastic locking orthosis in the prevention of floating toe after Weil osteotomy.

In all, 30 patients with metatarsalgia diagnosis submitted to Weil osteotomy were treated in the postoperative period with the Tucade dorsal thermoplastic locking orthosis.

The floating toe was not observed in this case series. There was 1 case of superficial wound irritation at the dorsal surgical incision and 1 case that evolved with transfer metatarsalgia. Statistical analyses were performed-American Orthopaedic Foot and Ankle Society Scale for lateral toes and extension of the lateral toes-using the t test, and P < .0001 was obtained for comparison of the preoperative and postoperative periods in the population studied.

The Tucade dorsal thermoplastic locking orthosis during the postoperative period of Weil osteotomy proved to be effective in the prevention of floating toes.

Therapeutic Level IV: Case Series.

Multifragmentary sesamoid bones of the hallux have established the concept of sesamoidea multipartita which is explained as a congenital characteristic of these bones. Sesamoid bones although fragmented are often asymptomatic as are, for example fragmented patellae. Evidence shows, however, that fragmentation of sesamoid bones is significantly more frequent in young people active in sports (soccer). The diagnosis of traumatic fractures and subsequent pain and disability is a challenge. Patients often present to physicians relatively late and are, therefore, treated in the acute phase long after onset of pain.

Inquisitive interview of the patient and precise examination together with a detailed radiological investigation (computed tomography) are essential to be able to determine a causal relation to the fragmentation of sesamoid bones. Treatment consists of an anatomical reconstruction of vital bone fragments possibly augmented with an autologous cancellous bone graft after debridement. Surgical approaches are longitudinal medial for the medial sesamoid bone and longitudinal plantar for the lateral sesamoid bone. The means of fixation mostly involves two 1.5 mm screws for optimal mechanical stability.

Disorders of the hallux sesamoids can be a source of considerable pain and disability. Inappropriate or inept removal can lead to further disability and pain. Surgical intervention should only follow careful accurate assessment, appropriate investigation, and failure of conservative treatments.

The prevalence and distribution of the sesamoid bones in the feet has been reported in the literature with a high degree of variability. This systematic review aims to provide a better estimate of the frequency of the sesamoids of the foot and their association with variables such as ancestry, gender, and side. Thirty-seven studies met the inclusion criteria and were submitted for meta-analyses, sensitivity analyses and proportion difference tests, whenever possible. At the metatarsophalangeal (MTP) joint of the hallux, sesamoids were nearly always present. At the interphalangeal (IP) joint, the pooled true estimates of large-sampled studies were: (1) an overall prevalence of 22.4 %, (2) a cadaveric rate at 71.6 %, and (3) a radiological rate (based on X-ray images) of 21.1 %. The pooled partition frequencies of the hallucal medial and lateral sesamoids were 10.7 and 1.3 %, respectively. Bipartism was the most frequent partition type (92 %), followed by tripartism (7.5 %) and quadripartism (0.5 %). Middle Eastern ancestry was associated with significantly lower hallucal partition rate (P < 0.0001) and African ancestry with significantly lower prevalence of the IP sesamoid than all other ethnicities (P < 0.001). Feet with a hallux valgus deformity seemed to be associated with significantly higher rate of partition of the medial sesamoid (odds ratio = 3) than that of the normal feet. The respective values of the pooled true prevalence in adults at the MTP joint for the 2nd, 3rd, 4th and 5th toes were 1.9, 0.32, 0.9 and 13 %, respectively. There was a significantly higher prevalence of tibial sesamoids vs lateral sesamoids, with pooled odds ratio of 34.7, 8, 4.8, and 2.27, respectively. Partition was found in around 10 % of the sesamoids of the 5th MTP joint; no partition was noted in the other toes. For most 2nd-5th MTP joints, European ancestry showed the highest frequency whereas African ancestry showed the lowest; Middle Eastern ancestry was in between. No sesamoids were found at the 4th proximal IP joint and at the 4th and 5th distal IP joints. No sesamoids were found at any IP joint in the feet of Middle Eastern and African populations. The pooled rates of the IP sesamoids of the second and third toes in European populations were 1.2 % for the 2nd proximal, 0.33 % for the second distal and 0.6 % for both IP joints of the third toe. This anatomical meta-analysis yielded results that are likely to be more accurate regarding the rates of the sesamoids in the foot, their laterality and partition. It also provided solid evidence for the genetic basis of the frequency distribution among the different populations.

The absence of both tibial and fibular hallucal sesamoids is an extremely rare condition. It can present as hallux valgus, hallux varus, or metatarsalgia. It can result from primary mesenchymal differentiation failure or an ossification problem. Preoperative magnetic resonance imaging can help to differentiate the problem and assist preoperative planning in the case of surgical correction of the associated hallux valgus deformity.

Leonardo da Vinci (1452-1519), world-renowned Italian renaissance master, is known for his contributions to, and broad interests in science and art. The objective of this work is to demonstrate the extent of his science by applying the use of his concepts to current models of foot and ankle mechanics.

The art and science of Leonardo Da Vinci were extensively analyzed by reviewing his original drawings and hand written notebooks as well as their English translation. Current medical journals including the topics of foot, ankle, and biomechanics were reviewed for modern evidence and application of his concepts. The library of Michigan State University and the electronic library of the Royal Library at Windsor Castle were extensively utilized.

From the depths of Santa Maria Nuova Hospital in Florence and Santo Spirito Hospital in Rome, through his commentary and anatomical drawings of around 30 cadaver dissections he performed, Leonardo da Vinci expressed his concept of foot and ankle anatomy and mechanics. He laid forth concepts, which vary little from current theories including those of proportion, statics and joint stability, sesamoid biomechanics, and structural support of the foot.

Leonardo da Vinci, by combining an interest in anatomy and a gift of genius and artistic ability laid a foundation of foot and ankle anatomy and mechanics that have been applied in modern clinical sciences. Leonardo in this way made important contributions to the practice of foot and ankle orthopedics.

The absence of the hallucal sesamoid is a rare condition. Rarer still is the presentation of adolescent hallux valgus with the absence of both hallucal sesamoid. Seven cases of absence of the tibial sesamoid bone and 3 cases of absence of the fibular sesamoid bone have been found in the literature, and only a single case of bilateral absence of both sesamoid bones with hallux varus has been reported. We would like to present a unique case of bilateral absence of the hallucal sesamoid in an 18-year-old woman with severe adolescent hallux valgus but no other apparent congenital deformity.

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.

The sesamoid complex is located centrally and plantar to the first metatarsal head, where they are imbedded within the plantar plate, which transmits 50% of body weight and more than 300% during push-off, is susceptible to numerous pathologies. These pathologies include sesamoiditis, stress fracture, avascular necrosis, osteochondral fractures, and chondromalacia, and are secondary to these large weight-bearing loads. This article discusses sesamoid conditions and their relationship with hallux limitus, and reviews the conditions that predispose the first metatarsophalangeal joint to osteoarthritic changes.

This article reviews the published literature regarding the surgical approaches to pathologies encountered within the forefoot, including arthroscopic and open techniques, and their treatment. We have demonstrated these surgical approaches with cadavers, to identify the key anatomical landmarks and safe zones for these surgical techniques, to prevent the complications associated with their treatment.

Turf toe injuries and sesamoid injuries are challenging because of the variety of causes that exist as sources of pain. Through a systematic approach to evaluation, injuries to the hallux metatarsophalangeal joint can be diagnosed properly. Correct diagnosis leads to accurate and efficient treatment. If conservative measures fail, operative interventions are available to relieve pain and restore function. With careful surgical technique and appropriate postoperative management, athletes can return to play and efficiently reach their pre-injury level of participation.

Sesamoid disorders are common causes of forefoot pain. Because of the significant mechanical stresses and anatomic variations involved, the sesamoid complex appears to be affected by numerous pathologic processes. These include acute fractures, stress fractures, nonunions, osteonecrosis, chondromalacia, and various inflammatory conditions labeled sesamoiditis. Treatment options include conservative management with orthotics and immobilization, as well as operative interventions that range from fracture/nonunion fixation to various approaches for sesamoidectomy. This article outlines the diagnosis and treatment of these entities and reviews the results of these treatments.

Despite the fact that the hallucal sesamoids play a crucial role in forefoot mechanics, disorders resulting from pathology of these structures are often overlooked or misdiagnosed. Avascular necrosis (AVN) of the hallucal sesamoids is a rare condition that must be differentiated from other pathologies, such as fractures, pseudarthrosis or osteomyelitis. We report on two patients with AVN of the fibular (lateral) hallucal sesamoid (Morbus Renander). In both patients the necrotic part of the fibular sesamoid was excised surgically after failed conservative therapy. The followup was 29 and 26 months. The clinical and radiological results showed a complete relief of pain in both patients without any complications or forefoot deformities. Recent literature and own experiences support non-operative initial management including anti-inflammatory medications, shoe modification and temporary limited weight bearing. If symptoms persist, surgical treatment with excision of the necrotic part of the sesamoid may be an alternative. Consideration by the surgeon should be given to protecting the neurovascular bundle and reattaching intrinsic tendons and ligaments if necessary. Satisfying results can be achieved by surgical removal.

The objective was to relate the incidence of the partition of the hallucal sesamoid bones to the size of the first metatarsal and the hallux valgus deformity.

In a sample of 474 radiographs, the frequency of appearance of bipartite sesamoids was studied. The length and relative protrusion of the first metatarsal, and the hallux abductus angle, were measured and compared between the feet with and without sesamoid partition.

The results showed that 14.6% of the feet studied had at least one partite sesamoid, that the sesamoid most frequently divided was the medial, and that unilateral partition was the most common. No difference was found in the incidence of partite sesamoids between men and women, or between left and right feet.

Protrusion and length of the first metatarsal are greater in feet with partite sesamoids than in feet without this condition. A significantly higher incidence of bipartite medial sesamoid was obtained in feet with hallux valgus compared with normal feet.

Misdiagnosed o sesamoid bone pathology in dancers may result in prolonged pain, disability, and career limitation. A thorough understanding of sesamoid disorders and appropriate treatment facilitates timely recovery. The potential loss of hallux plantar flexion strength consequent to sesamoidectomy is a major consideration for dancers.

An 18-year-old dance student sustained a delayed-union fracture of her lateral (fibular) sesamoid. Treatment included an inductive coupling external bone stimulator with pulsed electromagnetic field, activity, and weight-bearing restrictions, protective padding, strengthening, functional retraining, and progressive return to dance.

Following use of an external bone stimulator for 12 months, the dancer successfully returned to her previous level of dancing. Repeated SF-36 and Dance Functional Outcome System scores confirmed this improvement.

Loss of hallux plantar flexion strength with sesamoid resection can be devastating to a dancer who requires push-off strength for multiple turns and jumps. Treatment with bone stimulation was therefore selected over more invasive measures. The dancer was compliant with systematic functional progression. Improvement, as seen on radiographs and outcome scores, accompanied her full functional recovery.

Functional loss and clinical evidence of hallux malalignment have been reported to follow isolated tibial sesamoidectomy.

Thirty-two patients with isolated tibial sesamoidectomies were identified. Patients with a diagnosis of peripheral neuropathy, diabetes mellitus, inflammatory arthropathy or previous foot surgery were excluded as were patients who had concomitant joint realignment procedures. Twenty patients were available for followup with the Short Form-36 (SF-36), Foot Function Index (FFI) disability scale, visual analog scale (VAS), and questionnaire at an average of 62 (range 10 to 157) months after surgery. Fourteen patients returned for physical examination, radiographs, and pedographic and isokinetic examination.

Physical examination of the 14 patients did not reveal any significant change in clinical alignment, range of motion or tenderness. Preoperative and postoperative comparison radiographs did not reveal significant differences in the intermetatarsal (IM) angle, hallux valgus (HV) angle distal metatarsal articular angle (DMAA), or sesamoid alignment (sesamoid station). Postoperative outcome measurements (VAS, SF36, and FFI) for 20 patients found significant relief of pain and improved functional outcome. Computerized dynamic pedographic measurements (Performance Orthotic) for 12 patients did not reveal any altered plantar pressures in the region of the hallux metatarsophalangeal joint. Isokinetic measurements of ankle plantar flexion push-off strength in eight patients did not reveal significant differences in side-to-side measurements. Eighteen of 20 (90%) patients indicated that they were able to resume all preoperative activities; six (30%) had extreme difficulty or an inability to stand on tip toe, but this did not impact their activities of daily living or their athletic endeavors. Two patients (14.3%) developed transfer metatarsalgia, but only one was symptomatic.

Isolated tibial sesamoidectomy is a safe and effective treatment for recalcitrant tibial sesamoiditis. Hallux malalignment and deformity resulting in functional loss and change in hallux alignment can be avoided by meticulous surgical technique with repair of the soft tissues.

Clinical trial.

To determine the effect of 2 conservative intervention approaches for functional hallux limitus.

Metatarsophalangeal joint (MPJ) sprains are common and can result in long-term sequelae such as persistent pain and loss of range of motion (ROM) secondary to bony proliferation and articular degeneration. It is important to determine the most effective intervention for functional hallux limitus to decrease pain and restore function.

Twenty individuals with first MPJ pain, loss of motion, and weakness participated in the study. All patients received whirlpool, ultrasound, first MPJ mobilizations, calf and hamstring stretching, marble pick-up exercise, cold packs, and electrical stimulation. Ten of the 20 patients (experimental group) also received sesamoid mobilizations, flexor hallucis strengthening exercises, and gait training. Treatment was provided 3 times a week for 4 weeks. Measurements of first MPJ extension ROM, flexor hallucis strength, and subjective pain level were performed on the first and last visits.

Following the 12 therapy sessions, the experimental group achieved significantly greater MPJ extension ROM and flexor hallucis strength and had significantly lower pain levels as compared to the control group (P<.001).

These results suggest that sesamoid mobilization, flexor hallucis strengthening, and gait training should be included in the plan of care when treating an individual with functional hallux limitus.