Masamitsu Kido

Load Response of the Tarsal Bones in Patients with Flatfoot Deformity: In Vivo 3D Study

Background: The objective of this study was to evaluate the bone rotation of each joint in the hindfoot and compare the load response in healthy feet with that in flatfeet by analyzing the reconstructive three-dimensional (3D) CT image data during weightbearing. Methods: CT scans of 21 healthy feet and 21 feet with flatfoot deformity were taken in non-load condition followed by full-body weightbearing load condition. The images of the hindfoot bones were reconstructed into 3D models. The volume merge method in three planes was used to calculate the position of the talus relative to the tibia in the tibiotalar joint, the navicular relative to the talus in talonavicular joint, and the calcaneus relative to the talus in the talocalcaneal joint. Results: The talar position difference to the load response relative to the tibia in the tibiotalar joint in a flatfoot was 1.7 degrees more plantarflexed in comparison to that in a healthy foot (p = 0.031). The navicular position difference to the load response relative to the talus in the talonavicular joint was 2.3 degrees more everted (p = 0.0034). The calcaneal position difference to the load response relative to the talus in the talocalcaneal joint was 1.1 degrees more dorsiflexed (p = 0.0060) and 1.7 degrees more everted (p = 0.0018). Conclusion: Referring to previous cadaver study, regarding not only the cadaveric foot, but also the live foot, joint instability occurred in the hindfoot with load in patients with flatfoot. Clinical Relevance: The method used in this study might be applied to clinical analysis of foot diseases such as the staging of flatfoot and to biomechanical analysis to evaluate the effects of foot surgery in the future. Level of Evidence: III

Load response of the medial longitudinal arch in patients with flatfoot deformity: in vivo 3D study.

BACKGROUND The acquisition of flatfoot by an adult is thought to primarily be caused by posterior tibial tendon dysfunction, although some other causes, such as congenital flexible flatfoot or an accessory navicular, may also be responsible. The objective of this study was to evaluate the bone rotation of each joint in the medial longitudinal arch (MLA) and compare the response in healthy feet with that in flat feet by analyzing the reconstructive three-dimensional (3D) CT image data during weightbearing. METHODS CT scans of 20 healthy feet and 24 feet with flatfoot deformity were taken in non-load condition followed by full-body weightbearing condition. Images of the tibia and MLA bones (first metatarsal bone, cuneiforms, navicular, talus, and calcaneus) were reconstructed into 3D models. The volume merge method in three planes was used to calculate the bone-to-bone relative rotations. FINDINGS Under loading conditions, the flatfoot dorsiflexed more in the first tarsometatarsal joint, and everted more in the talonavicular and talocalcaneal joints compared with the healthy foot. The total relative rotation was larger in the flatfoot compared with the healthy foot only in the first tarsometatarsal joint. INTERPRETATION Supporting the MLA in the sagittal direction and the subtalar joint in the coronal direction may be useful for treating flatfoot deformity. The first tarsometatarsal joint may play an important role in diagnosing or treating flatfoot deformity.

A new radiographic view of the hindfoot

BackgroundA new radiographic view was proposed to evaluate the coronal plane alignment of the hindfoot under weightbearing conditions.MethodsWe studied 46 feet of individuals with normal appearing asymptomatic feet. On the antero-posterior roentgenogram using this new method, the line from the top of the sustentaculum tali to the lateral-inferior end of the posterior articular surface of the talus was obtained as the standard line showing varus or valgus of the calcaneus. We defined the angle between the longitudinal axis of the tibia and the standard line as described above as Varus-Valgus angle (V-V angle).ResultsThe mean (±SD) V-V angle of the 46 feet studied was 76.4 (±3.6) degrees.ConclusionThe findings from this study indicate that it is possible to estimate the alignment of the hindfoot quantitatively by comparing individuals to the mean V-V angle that we calculated in our sample, which was 76.4 degrees.

Weight-bearing three-dimensional computed tomography analysis of the forefoot in patients with flatfoot deformity

BACKGROUND The recent classifications for posterior tibial tendon dysfunction (PTTD) stage II are based on forefoot deformity, but there is still no consensus regarding a detailed explanation of the clinical condition. The purposes of this study were to clarify the clinical condition of flatfoot deformity using three-dimensional (3D) computed tomography (CT) imaging under loading on both healthy and flat feet and to compare 3D movement of the forefoot in response to load. METHODS Ten volunteers and 10 PTTD stage II patients with symptomatic flatfoot deformity were examined. CT scans of 20 healthy and 20 flat feet were performed under non-loading and full weight-bearing conditions. Images of the tibia and foot arch bones (talus, calcaneus, navicular, and first and fifth metatarsal bones) were reconstructed into 3D models. Rotations of individual tarsal bone or metatarsal bone were described by the Eulerian angles. RESULTS Compared with healthy feet, flat feet experienced plantarflexion of the fifth metatarsal bone relative to the first metatarsal bone under loading conditions. We defined this phenomenon as synonymous with forefoot varus on the coronal plane. CONCLUSIONS The results of this study have clarified part of the clinical condition of the forefoot in flatfoot deformity and may have applications in basic research of the staging advancement and substage classification of PTTD.

Effect of therapeutic insoles on the medial longitudinal arch in patients with flatfoot deformity: a three-dimensional loading computed tomography study.

BACKGROUND Insoles are frequently used in orthotic therapy as the standard conservative treatment for symptomatic flatfoot deformity to rebuild the arch and stabilize the foot. However, the effectiveness of therapeutic insoles remains unclear. In this study, we assessed the effectiveness of therapeutic insoles for flatfoot deformity using subject-based three-dimensional (3D) computed tomography (CT) models by evaluating the load responses of the bones in the medial longitudinal arch in vivo in 3D. METHODS We studied eight individuals (16 feet) with mild flatfoot deformity. CT scans were performed on both feet under non-loaded and full-body-loaded conditions, first with accessory insoles and then with therapeutic insoles under the same conditions. Three-dimensional CT models were constructed for the tibia and the tarsal and metatarsal bones of the medial longitudinal arch (i.e., first metatarsal bone, cuneiforms, navicular, talus, and calcaneus). The rotational angles between the tarsal bones were calculated under loading with accessory insoles or therapeutic insoles and compared. FINDINGS Compared with the accessory insoles, the therapeutic insoles significantly suppressed the eversion of the talocalcaneal joint. INTERPRETATION This is the first study to precisely verify the usefulness of therapeutic insoles (arch support and inner wedges) in vivo.

Effects of stress-shielding on the dynamic viscoelasticity and ordering of the collagen fibers in rabbit Achilles tendon.

We investigated the effects of stress‐shielding on both viscoelastic properties and microstructure of collagen fibers in the Achilles tendon by proton double‐quantum filtered (1H‐DQF) NMR spectroscopy. The right hind‐limbs of 20 Japanese white rabbits were immobilized for 4 weeks in a cast with the ankle in plantarflexion. Dynamic viscoelasticity of the Achilles tendons was measured using a viscoelastic spectrometer. Proton DQF NMR signals were analyzed to determine the residual dipolar coupling of bound water molecules in the Achilles tendons. Both the dynamic storage modulus (E′) and dynamic loss modulus (E″) decreased significantly in the Achilles tendons of the stress‐shielding group. The results of the 1H‐DQF NMR examination demonstrated significantly reduced residual dipolar coupling in the Achilles tendons of this same group. The disorientation of collagen fibers by stress‐shielding should contribute to degradation of the dynamic storage and loss moduli. The alterations of the collagen fiber orientation that contributed to the function of tendinous tissue can be evaluated by performing an analysis of 1H DQF NMR spectroscopy.

Features of hindfoot 3D kinetics in flat foot in ankle-joint maximal dorsiflexion and plantarflexion

BackgroundIt is difficult to evaluate the kinematics of flat foot from 2D images, and no definitive methods have so far been established to diagnose flat foot. This study evaluated hindfoot kinetics through the progression of posterior tibial tendon dysfunction (PTTD) in patients with stages II and III PTTD flat foot compared with those in normal patients under dorsiflexion and plantarflexion conditions using 3D computed tomography (CT) reconstruction images.MaterialsCT images were taken of 26 normal and 32 flat feet in neutral, plantarflexion, and dorsiflexion positions of the ankle joint, from which 3D virtual models were made of each hindfoot bone. The 3D bone motion of these models was calculated using volume merge methods in three major planes.ResultsTibiotalar-joint motion in ankle-joint plantarflexion became less plantarflexed (normal −41.2°, stage II −33.5°, stage III −25.3°) and less adducted (normal −13.9°, stage II −10.7°, stage III −5.6°) as the stage progressed. Talocalcaneal-joint motion in stage III became more plantarflexed (normal −0.8°, stage II −3.0°, stage III −8.7°) and more adducted (normal −0.3°, stage II −4.7°, stage III −10.3°) as the stage progressed. Talonavicular-joint motion in stage III became more plantarflexed (normal −7.2°, stage II −7.6°, stage III −14.9°) and more adducted (normal 1.0°, stage II −7.3°, stage III −17.9°) as the stage progressed.ConclusionsTibiotalar-joint plantarflexion decreased and talocalcaneal and talonavicular-joint adduction increased in the maximal ankle-joint plantarflexion in stage II in comparison with normal cases. Tibiotalar-joint plantarflexion and adduction were decreased and of the talocalcaneal and talonavicular joints increased in stage III in comparison with stage II cases.

A finite element model of flatfoot (Pes Planus) for improving surgical plan.

Flatfoot is a foot condition caused by the collapse of the medial arch of the foot, and it can result in problems such as severe pain, swelling, abnormal gait, and difficulty walking. Despite being a very common foot deformity, flatfoot is one of the least understood orthopaedic problems, and the opinions regarding its optimal treatment vary widely. In this paper, an FE model of a flatfoot is proposed that is based on CT measurements. Surface meshes of the bones and soft tissue were generated from CT images and then simplified to reduce the node density. A total of 62 ligaments, 9 tendons, and the plantar fascia were modeled manually. Volume meshes of the different components were generated and combined to form the completed flatfoot model. A dynamic FE formulation was derived, and a balanced standing simulation was performed. The model was validated by comparing stress distribution results from the simulation to experimental data.

Tarsal Tunnel Syndrome in Hemodialysis Patients A Case Series

Background: The purpose of our study was to investigate tarsal tunnel syndrome (TTS) arising in patients who have undergone maintenance dialysis at our facility and to evaluate the frequency, pathological characteristics, and diagnosis of TTS. Methods: We evaluated 1011 patients (mean age 65.1 years) undergoing maintenance dialysis from 2000 to 2006 at our hospital. In patients diagnosed with TTS, we examined clinical symptoms and imaging findings. In addition, we evaluated intraoperative findings in patients who had undergone surgery. A follow-up study was conducted for at least 1 year. Results: Five patients (7 ankles) (mean age 57.8 years) were diagnosed as have TTS, with a mean dialysis duration of 23.4 years (range, 7-30 years). With conservative treatment consisting of rest and a steroid injection, 4 ankles showed improvement. Surgery was performed on 3 ankles. Amyloidoma, nodular tumor fragile deposits in the soft tissue or thecal surface, proliferation of the synovial tendon sheath, and thickened joint capsule were recognized in 3 ankles, and a concomitant ganglion was recognized in 1 ankle. Histologically, the deposition of hyaline material was recognized in all tissues, including the walls of the ganglion or joint capsule, by staining to a pale red color using Congo red stain. An immunohistochemical study indicated positive staining by β-2 microglobulin staining. The flexor retinaculum was thin in all cases, with retinaculum-like thickness not found in carpal tunnel syndrome. Conclusions: We believe that the occurrence of TTS in dialysis patients was 0.5%, with a tendency to be more prevalent among patients undergoing maintenance dialysis for 5 or more years. The pathological process of TTS may be different from that of carpal tunnel syndrome. Level of Evidence: Level IV, retrospective case series.

Correlation between the outcome of extracorporeal shockwave therapy and pretreatment MRI findings for chronic plantar fasciitis

Abstract Background. The purpose of this study was to investigate the relationship between magnetic resonance imaging (MRI) findings before extracorporeal shockwave therapy (ESWT) and the treatment outcome of ESWT. Methods. This study examined 50 feet with chronic plantar fasciitis. The scores before ESWT and after a six-month follow-up were investigated using the Japanese Society for Surgery of the Foot (JSSF) Ankle-Hindfoot Scale and the Visual Analog Scale (VAS). MRI before ESWT was used for image evaluation. MRI revealed thickening of the plantar fascia (PF), and an investigation was conducted regarding the findings of a high-signal-intensity area (HSIA) inside the PF, edema near the PF, and bone marrow edema (BME) of the calcaneus. Results. The average JSSF score and VAS score improved significantly at follow-up. In total, 44 feet were noted in the improved group. MRI revealed that the average amounts of PF thickening did not significantly differ between the improved group and the non-improved group. HSIA, edema near the PF, and BME were observed in 36, 41, and 11 feet in the improved group, respectively; and 2, 4, and 2 feet in the non-improved group, respectively. Conclusions. An HSIA in the PF predicted symptom improvement more easily than other MRI findings. Level of Evidence: IV