Quantitative analysis of the locking position of the midtarsal joint

Radiographic measurements of the talus and calcaneus in the adult pes planus foot type

OBJECTIVE

A distinctive feature of the modern human foot is the presence of a medial longitudinal arch when weight-bearing. Although the talus and calcaneus play a major role in the structure and function of the human foot, the association between the morphology of these bones and longitudinal arch height has not been fully investigated. A better understanding of this relationship may assist in the interpretation of pedal remains of fossil hominins, where features of the foot and ankle morphology have been described as providing evidence for the presence of a longitudinal arch.

METHODS

For this study, weight-bearing radiographs of 103 patients from an urban US Level 1 trauma center, taken as part of a clinical examination for medical evaluation, were selected. These radiographs were classified as to foot type by arch height as defined using the calcaneal inclination angle. From this group, 68 radiographs were suitable for linear and angular measurements of the talus and 74 of the calcaneus. The relationships between these measurements and arch height were explored using least squared linear regression analysis.

RESULTS

The results demonstrate that angular measurements of the calcaneus (particularly those that reflect the relationship of the talar articular facets to each other and the tilt of the calcaneocuboid joint to the longitudinal axis of the calcaneus) are predictive of arch height (r² = .29-.44 p ≤ .001). All angular measurements of the talus and all examined linear measurements of both the talus and calcaneus were not predictive of arch height.

DISCUSSION

These results suggest that certain angular measurements of the calcaneus are associated with arch height in the modern human foot. While this information is useful in the interpretation of hominin pedal remains, the relationship of the morphology of these bones, as well as other bones of the foot, to arch height is complex, requiring further investigation.

Biomechanics and Orthotic Treatment of the Adult Acquired Flatfoot

The adult acquired flatfoot deformity resulting from posterior tibial tendon dysfunction is the result of rupture of the posterior tibial tendon as well as key ligaments of the ankle and hindfoot. Kinematic studies have verified certain levels of deformity causing hindfoot eversion, lowering of the medial longitudinal arch and forefoot abduction. The condition is progressive and left untreated will cause significant disability. Bracing with ankle-foot orthoses has shown promising results in arresting progression of deformity and avoiding debilitating surgery. Various types of ankle-foot orthoses have been studied in terms of effects on gait as well as efficacy in treatment.

Using the Biomechanical Examination to Guide Therapy

In trying to explain the myriad of foot deformities and symptoms that have slow onset and/or are considered to be overuse syndromes, clinicians have been trying to develop quantitative examinations to describe the cause of the patient's problems and to better individualize treatment modalities. This type of examination is called a biomechanical examination. This article discusses some of the more common portions of a biomechanical examination of the foot and lower extremity. It will also point out some ways that the information from a biomechanical examination can be applied in clinically treating patients.

The influence of selective arthrodesis on three-dimensional range of motion of hindfoot joint: A cadaveric study

BACKGROUND

The purpose of this study was to measure the three-dimensional range of motion of adjacent, unfused joint or joints after different arthrodesis of hindfoot.

METHODS

Sixteen fresh frozen cadaver feet were immobilized in the non-weight bearing position. The three-dimensional coordinates of markers in tarsal were measured in six directions (involving dorsiflexion-plantarflexion, eversion-inversion, and adduction-abduction) before and after single (involving subtalar joint, talonavicular joint, and calcaneocuboid joint) and double (talonavicular and calcaneocuboid joints) arthrodesis with a three-dimensional coordinate instrument. The range of motion of the joint was calculated with the least square method and matrix transformation.

FINDINGS

We found that the range of motion of joints in all direction was reduced significantly after any combination of selective arthrodesis (all p < 0.001). After arthrodesis of the subtalar joint, the motion of talonavicular joint was reduced by 72%, and that of calcaneocuboid joint by 36%. After arthrodesis of talonavicular joint, the motion of subtalar joint was diminished by 36%, and that of calcaneocuboid joint by 51%. After arthrodesis of calcaneocuboid joint, the motion of subtalar joint was decreased by 21%, and that of talonavicular joint by 42%. After double arthrodesis, the motion of subtalar joint was reduced by 62%.

INTERPRETATION

In single arthrodesis, subtalar arthrodesis had the greatest effect on the motion of unfused joints, and the least was the calcaneocuboid arthrodesis. The motion of the subtalar joint was eliminated more than half after double arthrodesis. The data provide a biomechanical rationale to ascertain the clinical implication of the arthrodesis.

Introduction: Why Are There so Many Different Surgeries for Hallux Valgus?

Hallux valgus is a common pathology of the foot and ankle. Surgical correction of the condition has been described as early as 1836. Since then, numerous different surgical techniques have been documented in the literature. One of the explanations as to why there are so many different surgeries for hallux valgus is the variety of etiologies attributed to causing the condition. This article discusses the etiologies associated with hallux valgus and describes a few of the surgeries commonly used to treat the deformity.

Plantar pressure distribution in a hyperpronated foot before and after intervention with an extraosseous talotarsal stabilization device-a retrospective study

Plantar pressure measurements have long been used by clinicians to provide information regarding potential impairments and disorders of the foot and ankle. Elevations in peak plantar pressures or a poor distribution of these pressures can be an indication of pathomechanics in the foot. Lower extremity deficits such as sensory impairment, foot deformities, limited joint mobility, and reduced plantar tissue thickness have been associated with high plantar pressures. The total pressures, pressure distribution, and peak pressures provide useful information to evaluate the abnormal functioning of the talotarsal joint. Instability of the talotarsal joint can result in excessive forces exerted on the joints and surrounding tissues in the foot that can then lead to dysfunction of the proximal musculoskeletal kinetic chain. In the present study, we performed a retrograde analysis of the pre- and postoperative measurements of the peak plantar pressures, peak forces, and area of contact between the foot and the ground during each phase of the gait cycle for 6 patients (12 feet) who had undergone a bilateral extraosseous talotarsal stabilization procedure using a type II extraosseous talotarsal stabilization device. After the procedure, a significant reduction was seen in the peak pressures (42%) over the entire foot and a significant increase in the contact area (19.7%) between the foot and the floor. This could imply that the extraosseous talotarsal stabilization procedure was effective in stabilizing the talotarsal joint complex, thus eliminating abnormal hindfoot motion and restoring the normal biomechanics of the foot and ankle complex, as indicated by a reduction and realignment of the peak plantar pressures and forces.

Patellofemoral pain: proximal, distal, and local factors, 2nd International Research Retreat

Patellofemoral pain (PFP) is one of the most common lower extremity conditions seen in orthopaedic practice. The mission of the second International Patellofemoral Pain Research Retreat was to bring together scientists and clinicians from around the world who are conducting research aimed at understanding the factors that contribute to the development and, consequently, the treatment of PFP. The format of the 2.5-day retreat included 2 keynote presentations, interspersed with 6 podium and 4 poster sessions. An important element of the retreat was the development of consensus statements that summarized the state of the research in each of the 4 presentation categories. In this supplement, you will find the consensus documents from the meeting, as well as the keynote addresses, schedule, and platform and poster presentation abstracts.

Effect of the posterior tibial and peroneal longus on the mechanical properties of the foot arch

BACKGROUND

The mechanical properties of the foot are controlled by many structures including muscles, tendons, ligaments, tarsal joints and bones. Among them, muscles make the dynamic changes of foot alignment, especially the posterior tibial (PT) and peroneal longus (PL) which contribute to maintaining the foot arch. The purpose of this study was to quantify the effect of PT and PL on the foot mechanical properties.

METHODS

The mechanical properties with a longitudinal load to the tibia was measured in eight cadaveric feet. The measurement was carried out with absence of tendon traction (control), the presence of isolated traction of each tendon of the PT or PL, and finally after simultaneous traction of both tendons.

RESULTS

The bone displacement significantly decreased with tendon traction. The stiffness significantly increased with PT traction compared to control, and significantly decreased with PL traction and with traction of both tendons. Among the four testing conditions, the energy during loading was least with isolated PT traction. The energy dissipation rate was significantly increased with PL traction and with traction on both tendons, whereas no significant difference existed with PT traction compared to control.

CONCLUSIONS

The PT increased the stiffness and reduces the energy stored in the foot. The PT acted to improve the energy efficiency of the load transmission. The PL decreased the stiffness and increased the energy stored.

CLINICAL RELEVANCE

PT and PL muscles affect the foot arch. Excessive or insufficient traction may cause some foot disorders.

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.

Biomechanics and clinical analysis of the adult acquired flatfoot

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

The midtarsal joint locking mechanism

BACKGROUND

The midtarsal joint, consisting of the talo-navicular and the calcaneocuboid joints, is presumed to be responsible for the foot being both flexible and rigid during different parts of the stance phase of gait. However, this mechanism has never been well quantified. This study explores the midtarsal joint locking mechanism by comparing the effect of hindfoot inversion and eversion on midfoot and forefoot mobility.

METHODS

Motion of the tibia, talus, calcaneus, navicular, cuboid and the first, second, and fifth metatarsals were measured in nine cadaver feet using Polhemus Fastrak electromagnetic sensors (EST GmbH and Co. KG, Kaiserslautern, Germany). The talus was fixed to the tibia, and then the forefoot was maximally dorsiflexed, plantarflexed, inverted, and everted, with the hindfoot in maximal eversion and inversion, for a total of eight test positions. The range of motion of the individual bones between maximal forefoot dorsiflexion and plantarflexion and between maximal forefoot inversion and eversion was calculated for the hindfoot in maximal eversion and inversion.

RESULTS

For the range of motion from maximal dorsiflexion to maximal plantarflexion there was significantly increased movement of the first, second, and fifth metatarsals in the sagittal plane (p-value = 0.003, 0.007, and 0.002, respectively) when the calcaneus was maximally everted compared to when the calcaneus was maximally inverted. No significant differences were detected for the range of motion from forefoot inversion to eversion for the two hindfoot positions.

CONCLUSIONS

This study demonstrated that motion in the forefoot is influenced by hindfoot position through the midtarsal joint. Specifically, the sagittal plane range of motion of the metatarsals is increased when the hindfoot is in valgus.

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

Variation in functional stability of the first metatarsocuneiform joint was analyzed between transverse plane deviated (adducted) and corrected first metatarsal positions in a closed kinetic chain model. Six fresh frozen cadaver specimens with intact ankles and feet were fitted with a custom fabricated titanium metatarsal jig, which allowed for manipulation of the first metatarsal in the transverse plane. Specimens were mounted into a custom-made acrylic load frame and axially loaded to 400 N. Radiowave three-dimensional tracking transducers were attached to the following osseous segments: first metatarsal head and base, medial cuneiform, and second metatarsal. A dorsally directed load was applied to the first metatarsal segment and resultant movements were measured. Repeated testing was performed on a transverse deviated and corrected first metatarsal positions with the hallux plantargrade and maximally dorsiflexed to engage the windlass mechanism. With the windlass mechanism engaged and first metatarsal corrected, a 26% increase in first ray plantarflexion occurred from a deviated to a corrected first metatarsal position (p < or = .05). This suggests that the windlass mechanism is more efficient when the first metatarsal, sesamoid apparatus, and hallux position are properly aligned with the orientation of the plantar aponeurosis. Clinically, this may explain the correlation of first ray hypermobility with the progression of bunion severity. Our study validates the earlier work of Hicks and adds additional insight into the functional stability in the medial column of the foot.