The three-dimensional kinematics and flexibility characteristics of the human ankle and subtalar joints--Part I: Kinematics

The in-vitro, three dimensional kinematic characteristics of the human ankle and subtalar joint were investigated in this study. The main goals of this investigation were: 1) To determine the range of motion of the foot-shank complex and the associated range of motion of the ankle and subtalar joints; 2) To determine the kinematic coupling characteristics of the foot-shank complex, and 3) To identify the relationship between movements at the ankle and subtalar joints and the resulting motion produced between the foot and the shank. The tests were conducted on fifteen fresh amputated lower limbs and consisted of incrementally displacing the foot with respect to the shank while the motion of the articulating bones was measured through a three dimensional position data acquisition system. The kinematic analysis was based on the helical axis parameters describing the incremental displacements between any two of the three articulating bones and on a joint coordinate system used to describe the relative position between the bones. From the results of this investigation it was concluded that: 1) The range of motion of the foot-shank complex in any direction (dorsiflexion/plantarflexion, inversion/eversion and internal rotation/external rotation) is larger than that of either the ankle joint or the subtalar joint.; 2) Large kinematic coupling values are present at the foot-shank complex in inversion/eversion and in internal rotation/external rotation. However, only a slight amount of coupling was observed to occur in dorsiflexion/plantarflexion.; 3) Neither the ankle joint nor the subtalar joint are acting as ideal hinge joints with a fixed axis of rotation.; 4) Motion of the foot-shank complex in any direction is the result of rotations at both the ankle and the subtalar joints. However, the contribution of the ankle joint to dorsiflexion/plantarflexion of the foot-shank complex is larger than that of the subtalar joint and the contribution of the subtalar joint to inversion/eversion is larger than that of the ankle joint.; 5) The ankle and the subtalar joints have an approximately equal contribution to internal rotation/external rotation movements of the foot-shank complex.     

Magnetic resonance imaging of the ankle joint and foot: possible diagnostic errors

The paper deals with the visualizing study of the ankle joint and foot by MRI and with the problems in the interpretation of magnetic resonance images in health. For this, 50 healthy volunteers without diseases and lesions of the ankle joint and foot were examined. The study was performed by using flexible superficial coils and T1-, T2-, and proton-weighed pulse-sequences in the orthogonal projections. The articular surfaces and cavity of the ankle joint were evaluated. The specific features of visualization of the muscles and tendons of this area and the pattern of fluid under their membranes were explored. The typical location of the "magic corner" phenomenon was revealed. The individual specific features of identification of the ligaments of the ankle joint and foot and plantar aponeurosis were defined. The features of visualization of bones simulating abnormalities were studied. A category of normalcy in the MRI of the ankle joint and foot was formulated.     

An image-based kinematic model of the tibiotalar and subtalar joints and its application to gait analysis in children with Juvenile Idiopathic Arthritis

In vivo estimates of tibiotalar and the subtalar joint kinematics can unveil unique information about gait biomechanics, especially in the presence of musculoskeletal disorders affecting the foot and ankle complex. Previous literature investigated the ankle kinematics on ex vivo data sets, but little has been reported for natural walking, and even less for pathological and juvenile populations. This paper proposes an MRI-based morphological fitting methodology for the personalised definition of the tibiotalar and the subtalar joint axes during gait, and investigated its application to characterise the ankle kinematics in twenty patients affected by Juvenile Idiopathic Arthritis (JIA). The estimated joint axes were in line with in vivo and ex vivo literature data and joint kinematics variation subsequent to inter-operator variability was in the order of 1°. The model allowed to investigate, for the first time in patients with JIA, the functional response to joint impairment. The joint kinematics highlighted changes over time that were consistent with changes in the patient’s clinical pattern and notably varied from patient to patient. The heterogeneous and patient-specific nature of the effects of JIA was confirmed by the absence of a correlation between a semi-quantitative MRI-based impairment score and a variety of investigated joint kinematics indexes. In conclusion, this study showed the feasibility of using MRI and morphological fitting to identify the tibiotalar and subtalar joint axes in a non-invasive patient-specific manner. The proposed methodology represents an innovative and reliable approach to the analysis of the ankle joint kinematics in pathological juvenile populations.     

Functional morphology of the hindlimb in some lacertilia

Based on a global exploration of the hindlimb in some lacertilian species, an equally global functional approach has been undertaken, which led to the concept of the crural mechanism, an integral mechanism comprising the knee joint and the joints between respectively tibia and fibula on the one hand and the astragalocalcaneum on the other. Simple models explain the position of muscles and ligaments in relation to the homonymous rotation of tibia and fibula as well as the relative anterior displacement of fibula in front of the tibia. The linkage of knee and ankle joints appears to be based on those morphological features in both proximal and distal joints, that preclude pure axial rotations of tibia and fibula without deviation of these bones, again in both knee and ankle. The final result appears to be an integral mechanism endowed with one degree of freedom. An attempt has been made to identify the significance of the crural mechanism for function of the hindlimb in sprawling gait.     

Influence of landing on the supination and pronation in the foot joint

The purpose of this study was to measure the changes of supination and pronation in the ankle joint at landing to quantify the influence of shock attenuation during landing. The subjects did two different motions, jumping down on the force platform from posterior and lateral views. The rear view of single foot contact in a jump from height of 30 and 60 cm showed a landing on the inside of the rear part of the foot (pronation) followed after about 0.03 sec by a rolling outward of the foot (supination). The variables describing changes in three angles of the ankle joint indicated that the standing position was more sensitive on the pronation and supination during ground contact.     

Guidelines for selective radiological assessment of inversion ankle injuries.

A prospective study was performed to establish definitive guidelines for selective use of radiography in the assessment of inversion ankle injuries. Five hundred patients were included, representing 3.2% of the workload of the department during the study period. There were 379 soft tissue injuries, 56 malleolar fractures, 40 avulsion fractures, 21 fractures at the base of the fifth metatarsal, and four calcaneal fractures. Multiple logistic regression identified distal fibular tenderness, age, and ability to bear weight as the most important clinical variables in predicting important fractures (p less than 0.001). A policy of requesting x ray examination of only those patients with distal fibular tenderness or inability to bear weight or aged over 60, with a further proviso that no foot radiographs should be obtained, would produce a 60% reduction in ankle radiography in this centre without detriment to patient care.     

Effect of simulated joint instability and bracing on ankle and subtalar joint flexibility

It is clinically challenging to distinguish between ankle and subtalar joints instability in vivo. Understanding the changes in load-displacement at the ankle and subtalar joints after ligament injuries may detect specific changes in joint characteristics that cannot be detected by investigating changes in range of motion alone. The effect of restricting joints end range of motion with ankle braces was already established, but little is known about the effect of an ankle brace on the flexibility of the injured ankle and subtalar joints. Therefore, the purposes of this study were to (1) understand how flexibility is affected at the ankle and subtalar joints after sectioning lateral and intrinsic ligaments during combined sagittal foot position and inversion and during internal rotation and (2) investigate the effect of a semi-rigid ankle brace on the ankle and subtalar joint flexibility. Kinematics and kinetics were collected from nine cadaver feet during inversion through the range of ankle flexion and during internal rotation. Motion was applied with and without a brace on an intact foot and after sequentially sectioning the calcaneofibular ligament (CFL) and the intrinsic ligaments. Segmental flexibility was defined as the slope of the angle-moment curve for each 1 Nm interval. Early flexibility significantly increased at the ankle and subtalar joint after CFL sectioning during inversion. The semi-rigid ankle brace significantly decreased early flexibility at the subtalar joint during inversion and internal rotation for all ligament conditions and at the ankle joint after all ligaments were cut.     

Spiral computed tomography in the diagnosis of ankle and foot injuries

The data on 187 patients with traumatic lesions of the ankle joint and foot were used to analyze the capacities of computed tomography (CT) in the diagnosis of this pathology. The efficiency of CT versus X-ray study was evaluated. Specific guidelines are given to make spital CT. CT is shown to be of the most informative value in the diagnosis of lesions of the tibial plateau, undisplaced fractures of the internal malleolus, small marginal comminuted fractures, and lesions of the distal tibiofibular syndesmosis. There is evidence for that CT plays a dominant role in the diagnosis of lesions of the talus and calcaneus. Emphasis is laid on the great value of secondary multi- and three-dimensional image reconstructions.     

Foot mechanics during the first six years of independent walking

Recognition of the changes during gait that occur normally as a part of growth is essential to prevent mislabeling those changes from adult gait as evidence of gait pathology. Currently, in the literature, the definition of a mature age for ankle joint dynamics is controversial (i.e., between 5 and 10 years). Moreover, the mature age of the metatarsophalangeal (MP) joint, which is essential for the functioning of the foot, has not been defined in the literature. Thus, the objective of the present study explored foot mechanics (ankle and MP joints) in young children to define a mature age of foot function. Forty-two healthy children between 1 and 6 years of age and eight adults were measured during gait. The ground reaction force (GRF), the MP and ankle joint angles, moments, powers, and 3D angles between the joint moment and the joint angular velocity vectors (3D angle α(M.ω)) were processed and compared between four age groups (2, 3.5, 5 and adults). Based on statistical analysis, the MP joint biomechanical parameters were similar between children (older than 2 years) and adults, hinting at a quick maturation of this joint mechanics. The ankle joint parameters and the GRFs (except for the frontal plane) showed an adult-like pattern in 5-year-old children. Some ankle joint parameters, such as the joint power and the 3D angle α(M.ω) still evolved significantly until 3.5 years. Based on these results, it would appear that foot maturation during gait is fully achieved at 5 years.     

足踝部慢性骨髓炎的手术治疗策略

目的:足踝部特殊的解剖结构使其在手术或创伤打击之后易发骨髓炎,本文介绍了足踝部慢性骨髓炎的治疗策略及治疗结果。方法:回顾性分析2010年1月到2015年12月于我科治疗的足踝部慢性骨髓炎患者的临床特点及治疗结果,纳入患者术后随访至少2年,有糖尿病或免疫缺陷者被排除在研究之外。骨髓炎的病因,原发部位,致病菌,是否累及临近关节及骨髓炎复发情况被纳入评估,所有患者术前均进行SPECT/CT检查,用以评估骨髓炎感染的范围以及是否累及临近关节。手术治疗策略包括彻底的病灶清除,去除死腔以及累及关节时进行关节融合等。结果:足踝部慢性骨髓炎最常见的病因是创伤后的开放骨折或脱位,占所有患者的70%。耐甲氧西林金黄色葡萄球菌和铜绿假单胞菌是最常见的致病病原体。在45%的患者中,骨髓炎侵犯邻近关节,所有累及关节患者均进行了关节融合术。平均住院天数为16.5天。20例患者中18例无复发。结论:足踝部慢性骨髓炎发生邻近关节侵犯时,在进行彻底的病灶清除和去除死腔后,进行关节融合可获得良好疗效。     

带线锚钉修复三角韧带损伤的效果及对患者踝关节功能的影响

目的:研究带线锚钉修复三角韧带损伤在踝关节骨折内固定治疗中的作用及对踝关节功能的影响。方法:回顾性分析2012年9月至2016年8月本院收治的72例裸关节骨折并三角韧带损伤患者并且行切开复位钢板置入内固定,及采取带线锚钉内固定方式修复三角韧带损伤视为观察组;另选取同期在本院进行踝关节骨折内固定治疗但不修复三角韧带的72例患者视为对照组。分析患者治疗前、治疗后1个月、3个月、6个月踝关节功能恢复情况,观察患侧内踝间隙和不良反应。结果:观察组在治疗后1个月、3个月、6个月的AOFAS评分显著高于对照组(P0.05)。观察组在治疗后6个月后的患侧内踝间隙显著小于对照组(P0.05)。结论:带线锚钉修复三角韧带损伤在踝关节骨折内固定治疗中,可明显降低患侧内踝间隙距离,可促进患者踝关节功能恢复,无严重不良反应,值得进一步广泛推广使用。     

单侧外固定架对胫腓骨严重开放性骨折的临床疗效

目的:探讨单侧外固定架对不同部位胫腓骨严重开放性骨折的临床治疗效果及关节恢复功能情况。方法:回顾性分析我院自2013年1月至2015年1月共收治胫腓骨严重开放骨折行单侧外固定术治疗患者,根据骨折部位的不同将所有病例分为三组,A组12例,为胫腓骨近端骨折或波及膝关节,固定时需要跨膝关节固定,B组30例,为胫腓骨中段骨折,固定时不跨关节,C组18例,为胫腓骨远端骨折或波及踝关节,固定时需跨踝关节固定。分别对其进行单侧外固定架手术治疗,术后对所有患者骨折愈合情况及膝、踝关节活动度统计,对比观察各组手术疗效。结果:所有手术均获得成功,无不良事件发生,A组下肢功能优良率为83.3%;B组为96.7%;C组为83.3%。下肢功能恢复情况B组与A、C组相比差异具有统计学意义(P0.05),A组与C组相比差异无统计学意义(P0.05)。A组膝、踝关节功能恢复优良率分别为膝66.7%,踝91.7%;B组为膝93.3%,踝96.7%;C组为膝94.4%,踝72.2%。膝关节功能恢复情况A组与B、C组相比差异具有统计学意义(P0.05),B组与C组相比差异无统计学意义(P0.05)。踝关节功能恢复情况C组与A、B组相比差异具有统计学意义(P0.05),A组与B组相比差异无统计学意义(P0.05)。结论:单侧外固定架对不同部位胫腓骨严重开放性骨折的治疗效果良好,关节恢复情况满意,值得临床推广。     

The role of intrinsic muscle flaps of the foot for bone coverage in foot and ankle defects in diabetic and nondiabetic patients

Local muscle flaps, pioneered by Ger in the late 1960s, were extensively used for foot and ankle reconstruction until the late 1970s when, with the evolution of microsurgery, microsurgical free flaps became the reconstructive method of choice. To assess whether the current underuse of local muscle flaps in foot and ankle surgery is justified, the authors identified from the Georgetown Limb Salvage Registry all patients who underwent foot and ankle reconstruction with local muscle flaps and microsurgical free flaps from 1990 through 1998. By protocol, flap coverage was the reconstructive choice for defects with exposed tendons, joints, or bone. Local muscle flaps were selected over free flaps if the defect was small (3 x 6 cm or less) and within reach of the local muscle flap. During the same time frame, the authors performed 45 free flaps (96 percent success rate) in the same areas when the defects were too large or out of reach of local muscle flaps. Thirty-two consecutive patients underwent local muscle flap reconstruction for 19 diabetic wounds and 13 traumatic wounds. All wounds, after debridement, had exposed bone at their base, with osteomyelitis being present in 52 percent of the diabetic wounds and in 70 percent of the nondiabetic wounds. Wounds were located in the hindfoot (47 percent), midfoot (44 percent), and ankle (9 percent). Vascular disease was more prevalent in the diabetic group, in which 42 percent of the affected limbs required revascularization procedures before reconstruction (versus 7 percent in the nondiabetic group). Subsequently, 83 total operations were required to heal the wounds, of which 46 percent were limited to debridement only. Thirty-four pedicled muscle flaps were used: 19 abductor digiti minimi (56 percent), nine abductor hallucis (26 percent), three extensor digitorum brevis (9 percent), two flexor digitorum brevis (6 percent), and one flexor digiti minimi (3 percent). An additional skin graft for complete coverage was required in 18 patients (53 percent). One patient died and one flap developed distal necrosis, for a 96 percent success rate. The complication rate was 26 percent and included patient death, dehiscence, and partial flap or split-thickness skin graft loss. Twenty-nine of the 32 wounds healed. One patient died in the postoperative period; in two others the wounds failed to heal and required below-knee amputations, for an overall limb salvage rate of 91 percent. Diabetes did not significantly affect healing and limb salvage rates. Diabetes, however, did affect healing times (twofold increase), length of stay (2.7 times as long), and long-term survival (63 percent survival in diabetic patients versus 100 percent in the trauma group). Local muscle flaps provide a simpler, less expensive, and successful alternative to microsurgical free flaps for foot and ankle defects that have exposed bone (with or without osteomyelitis), tendon, or joint at their base. Diabetes does not appear to adversely affect the effectiveness of these flaps. Local muscle flaps should remain on the forefront of possible reconstructive options when treating small foot and ankle wounds that have exposed bone, tendon, or joint.     

俯卧位后外侧入路联合内侧切口治疗三踝骨折35 例的临床疗效评价

目的:探讨在俯卧体位下采用后外侧入路联合内侧切口治疗三踝骨折方法的临床疗效及安全性。方法:选择2014年1月~2015年1月在我院治疗并由同一治疗组医生采用俯卧体位下治疗的三踝骨折患者35例,治疗外踝骨折时将钢板置于腓骨后侧或外侧,使用钢板或螺钉对后踝骨折进行固定,2枚拉力螺钉固定内踝。观察术后切口及骨折愈合、踝关节功能恢复情况。术后定期随访,采用AOFAS踝-后足评分标准对踝关节功能进行评价。结果:手术时长50~142 min,平均90 min,1例患者内侧切口出现局部红肿,抬高患肢及定期换药后局部红肿好转,未出现明显切口感染征象。2例病人术后出现足背部麻木,分别在术后6周、9周时消失。随访时间6~18月,平均随访15个月。术后3月X线显示所有病人骨折线模糊,骨痂生长良好,按美国足踝外科协会踝-后足评分系统评分:优28例,良5例,可2例,优良率94.29%。结论:在俯卧体位下采用后外侧切口治疗三踝骨折可一次性复位、固定后踝和外踝骨折,联合内侧切口可在一个体位下完成三踝骨折的手术,缩短手术时间,对软组织破坏少,骨折可获得解剖复位,术后踝关节功能恢复佳,可降低因反复翻身而污染术野的概率。     

Measurement of multi-segment foot joint angles during gait using a wearable system

Usually the measurement of multi-segment foot and ankle complex kinematics is done with stationary motion capture devices which are limited to use in a gait laboratory. This study aimed to propose and validate a wearable system to measure the foot and ankle complex joint angles during gait in daily conditions, and then to investigate its suitability for clinical evaluations. The foot and ankle complex consisted of four segments (shank, hindfoot, forefoot, and toes), with an inertial measurement unit (3D gyroscopes and 3D accelerometers) attached to each segment. The angles between the four segments were calculated in the sagittal, coronal, and transverse planes using a new algorithm combining strap-down integration and detection of low-acceleration instants. To validate the joint angles measured by the wearable system, three subjects walked on a treadmill for five minutes at three different speeds. A camera-based stationary system that used a cluster of markers on each segment was used as a reference. To test the suitability of the system for clinical evaluation, the joint angle ranges were compared between a group of 10 healthy subjects and a group of 12 patients with ankle osteoarthritis, during two 50-m walking trials where the wearable system was attached to each subject. On average, over all joints and walking speeds, the RMS differences and correlation coefficients between the angular curves obtained using the wearable system and the stationary system were 1 deg and 0.93, respectively. Moreover, this system was able to detect significant alteration of foot and ankle function between the group of patients with ankle osteoarthritis and the group of healthy subjects. In conclusion, this wearable system was accurate and suitable for clinical evaluation when used to measure the multi-segment foot and ankle complex kinematics during long-distance walks in daily life conditions.     

Modeling the stance leg in two-dimensional analyses of sprinting: inclusion of the MTP joint affects joint kinetics

Two-dimensional analyses of sprint kinetics are commonly undertaken but often ignore the metatarsalphalangeal (MTP) joint and model the foot as a single segment. Due to the linked-segment nature of inverse dynamics analyses, the aim of this study was to investigate the effect of ignoring the MTP joint on the calculated joint kinetics at the other stance leg joints during sprinting. High-speed video and force platform data were collected from four to five trials for each of three international athletes. Resultant joint moments, powers, and net work at the stance leg joints during the first stance phase after block clearance were calculated using three different foot models. By ignoring the MTP joint, peak extensor moments at the ankle, knee, and hip were on average 35% higher (p < .05 for each athlete), 40% lower (p < .05), and 9% higher (p > .05), respectively, than those calculated with the MTP joint included. Peak ankle and knee joint powers and net work at all joints were also significantly (p < .05) different. By ignoring a genuine MTP joint plantar flexor moment, artificially high peak ankle joint moments are calculated, and these also affect the calculated joint kinetics at the knee.     

A standardized x-ray examination of mandibular fractures

Proceeding from an x-ray examination of 143 patients with mandibular fractures, the most informative methods and projections as well as the order of their use with account of the site of a fracture, were determined. The most informative method in all fracture sites was orthopantomography; panoramic roentgenography was indicated only in fractures of the frontal part. If panoramic tomography cannot be done, roentgenography or electroroentgenography in the frontal-nasal projection is recommended. If panoramic roentgenography cannot be done, extraoral roentgenography is indicated in the diagnosis of fractures of the frontal part of the mandible.     

Influence of kinematic analysis methods on detecting ankle and subtalar joint instability

Patients with subtalar joint instability may be misdiagnosed with ankle instability, which may lead to chronic instability at the subtalar joint. Therefore, it is important to understand the difference in kinematics after ligament sectioning and differentiate the changes in kinematics between ankle and subtalar instability. Three methods may be used to determine the joint kinematics; the Euler angles, the Joint Coordinate System (JCS) and the helical axis (HA). The purpose of this study was to investigate the influence of using either method to detect subtalar and ankle joints instability. 3D kinematics at the ankle and subtalar joint were analyzed on 8 cadaveric specimens while the foot was intact and after sequentially sectioning the anterior talofibular ligament (ATFL), the calcaneofibular ligament (CFL), the cervical ligament and the interosseous talocalcaneal ligament (ITCL). Comparison in kinematics calculated from sensor and anatomical landmarks was conducted as well as the influence of Euler angles and JCS rotation sequence (between ISB recommendation and previous research) on the subtalar joint. All data showed a significant increase in inversion when the ITCL was sectioned. There were differences in the data calculated using sensors coordinate systems vs. anatomic coordinate systems. Anatomic coordinate systems were recommended for these calculations. The Euler angle and JCS gave similar results. Differences in Euler angles and JCS sequence lead to the same conclusion in detecting instability at the ankle and subtalar joint. As expected, the HA detected instability in plantarflexion at the ankle joint and in inversion at the subtalar joint.     

Rationalising requests for x-ray examination of acute ankle injuries.

Radiographs of injured ankles represent about 1 in 50 of all radiological examinations. The notes and radiographs of 100 patients with ankle injuries were reviewed, and the films of a further 93 patients who had ankle fractures treated by immobilisation were also scrutinised to assess the presence of absence of soft tissue swelling over the malleoli. Any accompanying radiographs of the foot requested at the same time were also studied. In 65 of the 100 cases of ankle injury there was no soft tissue swelling, and none of the patients had a major fracture, while 92 of the 93 patients with a major fracture had soft tissue swelling at the level of the malleoli. In 32 of the 100 cases of ankle injury foot radiographs had also been requested, but only three foot injuries were found. If the simple maxim of "No swelling adjacent to a malleolus, no radiographs" were applied radiography of twisted ankles could be reduced by as much as two-thirds. Moreover, if this maxim included the rider "and no routine foot films" the total casualty radiographic work load could be reduced by 8%.