Magnetization transfer-based 3D visualization of foot peripheral nerves.

PURPOSE: To investigate magnetization transfer (MT) effects as a new source of contrast for imaging and tracking of peripheral foot nerves. MATERIALS AND METHODS: Two sets of 3D spoiled gradient-echo images acquired with and without a saturation pulse were used to generate MT ratio (MTR) maps of 260 μm in-plane resolution for eight volunteers at 3T. Scan parameters were adjusted to minimize signal loss due to T2 dephasing, and a dedicated coil was used to improve the inherently low signal-to-noise ratio of small voxels. Resulting MTR values in foot nerves were compared with those in surrounding muscle tissue. RESULTS: Average MTR values for muscle (45.5 ± 1.4%) and nerve (21.4 ± 3.1%) were significantly different (P < 0.0001). In general, the difference in MTR values was sufficiently large to allow for intensity-based segmentation and tracking of foot nerves in individual subjects. This procedure was termed MT-based 3D visualization. CONCLUSION: The MTR serves as a new source of contrast for imaging of peripheral foot nerves and provides a means for high spatial resolution tracking of these structures. The proposed methodology is directly applicable on standard clinical MR scanners and could be applied to systemic pathologies, such as diabetes.

S'intégrer balle au pied: Le rôle des clubs de foot de migrants en Suisse

L'existence de clubs de foot de migrants favorise-t-elle ou empêche-t-elle le développement de liens sociaux avec les membres de clubs "autochtones" et plus largement avec les autres acteurs du tissu associatif régional ? Les auteurs de l'article portent particulièrement leur attention sur les relations crées et entretenues sur le terrain de jeu, à partir d'une recherche effectuée entre 2009 et 2011 auprès de douze clubs en Suisse. Ils s'intéressent tant à la composition de leurs effectifs, en terme d'origine nationale et culturelle, qu'au rôle de socialisation qu'ils peuvent jouer vis-à-vis de leurs membres et de passeur vers un processus dynamique d'intégration à construire et à assumer.

High-intensity running and plantar-flexor fatigability and plantar-pressure distribution in adolescent runners.

CONTEXT: Fatigue-induced alterations in foot mechanics may lead to structural overload and injury. OBJECTIVES: To investigate how a high-intensity running exercise to exhaustion modifies ankle plantar-flexor and dorsiflexor strength and fatigability, as well as plantar-pressure distribution in adolescent runners. DESIGN: Controlled laboratory study. SETTING: Academy research laboratory. PATIENTS OR OTHER PARTICIPANTS: Eleven male adolescent distance runners (age = 16.9 ± 2.0 years, height = 170.6 ± 10.9 cm, mass = 54.6 ± 8.6 kg) were tested. INTERVENTION(S): All participants performed an exhausting run on a treadmill. An isokinetic plantar-flexor and dorsiflexor maximal-strength test and a fatigue test were performed before and after the exhausting run. Plantar-pressure distribution was assessed at the beginning and end of the exhausting run. MAIN OUTCOME MEASURE(S): We recorded plantar-flexor and dorsiflexor peak torques and calculated the fatigue index. Plantar-pressure measurements were recorded 1 minute after the start of the run and before exhaustion. Plantar variables (ie, mean area, contact time, mean pressure, relative load) were determined for 9 selected regions. RESULTS: Isokinetic peak torques were similar before and after the run in both muscle groups, whereas the fatigue index increased in plantar flexion (28.1%; P = .01) but not in dorsiflexion. For the whole foot, mean pressure decreased from 1 minute to the end (-3.4%; P = .003); however, mean area (9.5%; P = .005) and relative load (7.2%; P = .009) increased under the medial midfoot, and contact time increased under the central forefoot (8.3%; P = .01) and the lesser toes (8.9%; P = .008). CONCLUSIONS: Fatigue resistance in the plantar flexors declined after a high-intensity running bout performed by adolescent male distance runners. This phenomenon was associated with increased loading under the medial arch in the fatigued state but without any excessive pronation.

Efficacy of a hip flexion assist orthosis in adults with hemiparesis after stroke.

Background During gait, the hip flexors generate 40% of the total power. Nevertheless, no device has been tested extensively for clinical purposes to cope with weakness in the hip flexors in patients with stroke. Objective The purpose of this study was to assess the efficacy and safety of a newly developed hip flexion assist orthosis in adult patients with hemiparesis after stroke. Design The study used a prospective, randomized, before-after trial design. The inclusion criteria were hemiparesis resulting from stroke (onset ≥8 weeks); ability to walk, even if with assistance; and hip flexion weakness (Medical Research Council Scale score ≤4).¦METHODS: /b> The main outcome measures were the 10-Meter Walk Test and the Six-Minute Walk Test. Patients also were evaluated with the Trunk Control Test, the Functional Ambulation Categories, the Motricity Index, and hip flexor strength on the Medical Research Council Scale. Sixty-two survivors of stroke were tested in random order with and without the orthosis. Any adverse event associated with its use was recorded.¦RESULTS: /b> Both the Six-Minute Walk Test and the 10-Meter Walk Test scores improved with the use of the orthosis. A significant negative correlation was found for improvement between scores on the 2 main outcome measures with the orthosis and the Functional Ambulation Categories scores. The improvement in Six-Minute Walk Test scores with the orthosis was related inversely to hip flexor strength.¦CONCLUSIONS: /b> The data showed that the use of a hip flexion assist orthosis can improve gait in patients with poststroke hemiparesis, particularly those with more severe walking impairment.

The relationship between fear of falling and foot clearance in older people

Introduction : Fear of falling (FOF) is associated with falls and modifications in gait parameters. Foot clearance during walking is directly linked to tripping and falling. The relationship between FOF and foot Downloaded from http://gerontologist.oxfordjournals.org/ at Université & EPFL Lausanne on January 23, 2013 436 The Gerontological Society of America clearance has never been evaluated. Methods : Participants (N=568, aged 66 to 71 years, 57.2% women) underwent gait parameters measurements using footworn sensors. Specific foot clearance parameters evaluated included maximal and minimal heel and toe clearances and their variability. FOF was assessed using a single question. Results : Overall, 27.4% of the participants reported FOF. Compared to the others, participants with FOF had decreased maximal heel (28.9 vs 30.4 cm, p<.001) and toe clearance (12.5 vs 13.8 cm, p<.001), and decreased minimal toe clearance variability (SD 3.7 vs 4.0 cm, p<.001). Conclusion : These preliminary results suggest a relationship between FOF and foot clearance parameters. Multivariate analyses are underway.

Bone regeneration and stem cells.

?  Introduction ?  Bone fracture healing and healing problems ?  Biomaterial scaffolds and tissue engineering in bone formation -  Bone tissue engineering -  Biomaterial scaffolds -  Synthetic scaffolds -  Micro- and nanostructural properties of scaffolds -  Conclusion ?  Mesenchymal stem cells and osteogenesis -  Bone tissue -  Origin of osteoblasts -  Isolation and characterization of bone marrow derived MSC -  In vitro differentiation of MSC into osteoblast lineage cells -  In vivo differentiation of MSC into bone -  Factors and pathways controlling osteoblast differentiation of hMSC -  Defining the relationship between osteoblast and adipocyte differentiation from MSC -  MSC and sex hormones -  Effect of aging on osteoblastogenesis -  Conclusion ?  Embryonic, foetal and adult stem cells in osteogenesis -  Cell-based therapies for bone -  Specific features of bone cells needed to be advantageous for clinical use -  Development of therapeutic biological agents -  Clinical application concerns -  Conclusion ?  Platelet-rich plasma (PRP), growth factors and osteogenesis -  PRP effects in vitro on the cells involved in bone repair -  PRP effects on osteoblasts -  PRP effects on osteoclasts -  PRP effects on endothelial cells -  PRP effects in vivo on experimental animals -  The clinical use of PRP for bone repair -  Non-union -  Distraction osteogenesis -  Spinal fusion -  Foot and ankle surgery -  Total knee arthroplasty -  Odontostomatology and maxillofacial surgery -  Conclusion ?  Molecular control of osteogenesis -  TGF-β signalling -  FGF signalling -  IGF signalling -  PDGF signalling -  MAPK signalling pathway -  Wnt signalling pathway -  Hedgehog signalling -  Notch signalling -  Ephrin signalling -  Transcription factors regulating osteoblast differentiation -  Conclusion ?  Summary This invited review covers research areas of central importance for orthopaedic and maxillofacial bone tissue repair, including normal fracture healing and healing problems, biomaterial scaffolds for tissue engineering, mesenchymal and foetal stem cells, effects of sex steroids on mesenchymal stem cells, use of platelet-rich plasma for tissue repair, osteogenesis and its molecular markers. A variety of cells in addition to stem cells, as well as advances in materials science to meet specific requirements for bone and soft tissue regeneration by addition of bioactive molecules, are discussed.

Traumatic rupture of both peroneal longus and brevis tendons.

Injuries of peroneal tendons are rare. Diagnosis of traumatic rupture is often late and presents as chronic ankle instability. A case of a complete traumatic rupture of both peroneal longus and brevis tendons with acute clinical and radiological diagnosis is presented. Surgical repair was performed by direct end-to-end suture on the 4th day after trauma, with excellent functional outcome at 1-year follow-up.

Atteintes de la chevill et du tarse postérieur dans les maladies métaboliques

De nombreuses maladies métaboliques peuvent atteindre la cheville et le tarse postérieur. Dans la phase aiguë, la goutte peut toucher l'arrière-pied, la cheville, le médio-tarse ou le tendon calcanéen. Une rougeur intense des tissus souscutanés du dos du pied peut être en rapport avec une inflammation liée à des microtophus sous-cutanés. Un diagnostic de certitude se fait par la mise en évidence de cristaux d'urate de sodium dans le liquide de ponction articulaire ou dans les tissus. L'imagerie par tomodensitométrie ou par échographie peut orienter de façon pratiquement certaine le diagnostic. Le traitement de la goutte de l'arrière-pied fait appel aux antiinflammatoires, aux anti-inflammatoires non stéroïdiens (AINS) et à la colchicine. Dans la phase chronique, un traitement hypo-uricémiant au long terme est à instaurer. L'hémochromatose se manifeste principalement sous forme d'une arthrose, liée souvent à une chondrocalcinose de la cheville et du tarse postérieur. L'enthésopathie hyperostosante diffuse peut causer des talalgies ou des douleurs du fascia plantaire liées à des exostoses. L'hypercholestérolémie familiale provoque souvent des xanthomes tendineux des tendons calcanéens. Des calcifications apatitiques de la région du talon peuvent s'observer, notamment chez des patients en hémodialyse chronique. Numerous metabolic diseases can affect the ankle and the hind-foot. In the acute phase, gout can affect the rear of the foot, the ankle, the mid-foot and the calcaneal (Achilles) tendon. Intense redness of the subcutaneous tissue of the back of the foot can be present in conjunction with inflammation associated with subcutaneous micro-tophaceous deposits. A definitive diagnosis is made by confirming the existence of sodium urate crystals in joint puncture fluid or in tissue. CT scan or ultrasonography images can also be used to provide a fairly definitive diagnosis. Treatment of gout of the rear of the foot requires the use of anti-inflammatory medication, NSAIDs and colchicine. In the chronic phase, long-term hypouricemic therapy is to be used. Haemochromatosis mainly shows in the form of arthritis, often associated with chondrocalcinosis of the ankle and hind-foot. A diffuse hyperostosis enthesopathy can cause talalgia or pain to the plantar fascia associated with exostoses. Familial hypercholesterolaemia often leads to tendinous xanthoma on the calcaneal tendons. Apatitic calcifications to the heel can also be observed, especially undergoing chronic haemodialysis.

Effects of a 5-h hilly running on ankle plantar and dorsal flexor force and fatigability

This study aimed to examine the effects of a 5-h hilly run on ankle plantar (PF) and dorsal flexor (DF) force and fatigability. It was hypothesised that DF fatigue/fatigability would be greater than PF fatigue/fatigability. Eight male trail long distance runners (42.5 ± 5.9 years) were tested for ankle PF and DF maximal voluntary isokinetic contraction strength and fatigue resistance tests (percent decrement score), maximal voluntary and electrically evoked isometric contraction strength before and after the run. Maximal EMG root mean square (RMS(max)) and mean power frequency (MPF) values of the tibialis anterior (TA), gastrocnemius lateralis (GL) and soleus (SOL) EMG activity were calculated. The peak torque of the potentiated high- and low-frequency doublets and the ratio of paired stimulation peak torques at 10 Hz over 100 Hz (Db10:100) were analysed for PF. Maximal voluntary isometric contraction strength of PF decreased from pre- to post-run (-17.0 ± 6.2%; P < 0.05), but no significant decrease was evident for DF (-7.9 ± 6.2%). Maximal voluntary isokinetic contraction strength and fatigue resistance remained unchanged for both PF and DF. RMS(max) SOL during maximal voluntary isometric contraction and RMS(max) TA during maximal voluntary isokinetic contraction were decreased (P < 0.05) after the run. For MPF, a significant decrease for TA (P < 0.05) was found and the ratio Db10:100 decreased for PF (-6.5 ± 6.0%; P < 0.05). In conclusion, significant isometric strength loss was only detected for PF after a 5-h hilly run and was partly due to low-frequency fatigue. This study contradicted the hypothesis that neuromuscular alterations due to prolonged hilly running are predominant for DF.

The isolated talonavicular arthrodesis.

Based on a high percentage of good results, retrospective studies strongly suggest that isolated talonavicular arthrodesis provides efficient pain relief and functional improvement in case of talonavicular arthritis in rheumatoid arthritis, primary or posttraumatic arthritis, flexible acquired flatfoot deformity, residual dorsolateral subluxation of the talonavicular joint after surgical treatment of clubfoot, and some neurologic disorders. However, prospective trials with rigorous methodology are required to establish evidence of efficacy for this procedure. Well-designed biomechanical studies have demonstrated the key role of the talonavicular joint in the complex hindfoot motion and may serve as baseline for further prospective studies.

The characteristics of gait in Charcot-Marie-Tooth disease types I and II.

Certain typical gait characteristics such as foot-drop and foot supination are well described in Charcot-Marie-Tooth disease. These are directly related to the primary disease and due to the weakness of ankle dorsiflexors and everters characteristic of this hereditary neuropathy. We analysed 16 subjects aged 8-52 years old (11 with type I, 5 with type II Charcot-Marie-Tooth disease) using three-dimensional gait analysis and identified kinematic features previously unreported. These patients showed a combination of tight tendo achillei, foot-drop, failure of plantar flexion and increased foot supination, but also presented with excessive internal rotation of the knee and/or tibia, knee hyperextension in stance, excessive external rotation at the hips and decreased hip adduction in stance (typical of a broad based gait). These proximal features could have been an adaptation to or consequence of the disrupted ankle and foot biomechanics, however a direct relation to the neuropathy is also possible since sub-normal muscle power was observed at the proximal levels in most subjects on both manual testing and kinetic analysis. Gait analysis is a useful tool in defining the characteristic gait of patients with Charcot-Marie-Tooth disease.

Changes in leg spring behaviour, plantar loading and foot mobility magnitude induced by an exhaustive treadmill run in adolescent middle-distance runners.

OBJECTIVES: This study aimed to determine adjustments in spring-mass model characteristics, plantar loading and foot mobility induced by an exhaustive run. DESIGN: Within-participants repeated measures. METHODS: Eleven highly-trained adolescent middle-distance runners ran to exhaustion on a treadmill at a constant velocity corresponding to 95% of velocity associated with VO₂max (17.8 ± 1.4 kmh(-1), time to exhaustion=8.8 ± 3.4 min). Contact time obtained from plantar pressure sensors was used to estimate spring-mass model characteristics, which were recorded (during 30 s) 1 min after the start and prior to exhaustion using pressure insoles. Foot mobility magnitude (a composite measure of vertical and medial-lateral mobility of the midfoot) was measured before and after the run. RESULTS: Mean contact area (foot to ground), contact time, peak vertical ground reaction force, centre of mass vertical displacement and leg compression increased significantly with fatigue, while flight time, leg stiffness and mean pressure decreased. Leg stiffness decreased because leg compression increased to a larger extent than peak vertical ground reaction forces. Step length, step frequency and foot mobility magnitude did not change at exhaustion. CONCLUSIONS: The stride pattern of adolescents when running on a treadmill at high constant velocity deteriorates near exhaustion, as evidenced by impaired leg-spring behaviour (leg stiffness) and altered plantar loading.

The scarf osteotomy for the treatment of hallux valgus deformity: a review of 84 cases.

This study reviewed the subjective, clinical and radiological outcome of 71 patients (84 feet) treated by scarf osteotomy for hallux valgus deformity at our institution from 1995 to 1998 with an average follow-up time of 22 months (range, 17 to 48 months). At the time of follow-up, 39% of the patients were very satisfied, 50% were satisfied and 11% were not satisfied. The mean AOFAS score raised significantly from 43 points (14-68) preoperatively to 82 points (39 to 100) at follow-up (p &lt; 0.001). The radiological angles including M1-M2, M1-P1, M1-M5 and DMAA improved significantly (p &lt; 0.001). Among the 16 complications recorded, seven (8%) were minor and nine (11%) required an additional procedure. The scarf osteotomy of the first metatarsal coupled with a lateral soft-tissue release and, in three-quarters of our cases, with a basal closing wedge varisation osteotomy of the first phalanx, resulted in overall high satisfaction rate as well as significant clinical and radiological improvements in our series. Nevertheless, the range of motion of the first MP joint remained low: 30 degrees to 74 degrees in 52 patients (62%) and &lt;30 degrees in four patients (5%). Furthermore, the mobility of the first ray as well as the consequences of the procedure in the sagittal plane need to be assessed more accurately, and this may be achieved by incorporating measurement of the plantar pressures in the forefoot area into the global rating system.