Biometry of the calcaneocuboid joint: biomechanical implications.

Precise biometric data of calcaneus, cuboid bones and calcaneocuboid joint are not alluded to in textbooks of anatomy. This study focussed on the biometry of 50 calcanei, 30 cuboid dry bones, and anatomical specimens of 21 transverse tarsal joints. Measurement of the length, width, angular orientation, contact surface and radius of curvature, rolling band of the joints surfaces according to the main axes were performed. The results focussed on biometric variations with several morphological types never identified previously. Measurements obtained on dry bones and anatomical specimens with the functions of ligaments were distinguished. The morphology of the calcaneus could explain the results of osteotomy procedures for the treatment of adult flatfoot. A better knowledge of the joint surfaces and biometric data would generate a modeling of the calcaneocuboid joint and function in locking the transverse tarsal joint.

Endopelvic migration of a sternoclavicular K-wire. Case report and review of literature.

We report a unique case, never before published, of sternoclavicular joint fixation K-wire migration to the pelvic region, in a 56 year-old man. Two years previously, sternoclavicular dislocation had been fixed by three wires. A transitory episode of precordial thoracic pain followed by iterative abdominal pain accompanied the migration. Extraction was performed five years later. Scapular K-wire migration is frequent. The proximity of cardiovascular structures may have fatal consequences. This type of internal fixation raises questions, and migration prevention needs to be taken into account. Medical complications and the legal context are major factors leading us to abandon this type of osteosynthesis. Once migration has been diagnosed, the wire should be removed without delay.

Biometry of bone components in the talonavicular joint: a cadaver study.

INTRODUCTION: Exhaustive biometric data of the talus and the navicular bones have not been reported in the classical anatomy treatises. HYPOTHESIS: The radiographic measurements, being variable according to the X-ray beam inclination, have no real value. This biometric analysis aimed to specify the characteristics of the constitutive bone components of the talonavicular joint. MATERIAL AND METHODS: This anatomic study investigated the biometry of the talus and the navicular bones separated from anatomic specimens with no previous disease history from adult subjects whose sex was unknown. It was completed by in situ dissection and evaluation of talonavicular and talocalcaneal joints conducted to gain an understanding of the bone specimens in three dimensions. The measurements were taken using a highly precise measuring tape and a comparator providing the length and the width of the articular surfaces. The comparator determined the surface pattern and the radii of curvature in the two main axes. RESULTS: The results emphasize the variations in the bone specimens. Three morphotypes emerged, which had never been identified before. DISCUSSION AND CONCLUSION: These biometric data make up a database designed to improve clinical exploration. They can be used as landmarks for fundamental comparative research between all the bone structures of the hindfoot and thus provide a logical classification of the different pathological conditions and a reasoned adaptation of therapeutic protocols. LEVEL OF EVIDENCE: Experimental study, level IV.

Chronic ankle instability: biomechanics and pathomechanics of ligaments injury and associated lesions.

The objective of this study was to evaluate the conditions of ankle stability and the morphological and/or lesional factors in sprains that determine when instability becomes chronic. It is based on a review of the literature and the data from the 2008 Sofcot symposium. The biomechanics of the ankle cannot be reduced to a simple flexion-extension movement with one degree of freedom as characterized by the talocrural joint: its function cannot be dissociated from the subtalar joint, allowing the foot to adapt to the ground surface. Functional stability is related to the combination of the particular biometry of the joint surfaces and a multiaxial ligament system. The bone morphology of the talus, shaped like a truncated cone, explains the potential instability in plantar flexion; the radii of curvature of the talar dome have a variable mediolateral distribution: most often the medial radius of curvature is inferior to the lateral radius of curvature (66%), sometimes equal (19%), or inverted (15%). Joint kinematics, combining rotation and slide, can therefore be modulated by the talar morphology, explaining the occurrence of at-risk ankles. Ligament stability relies on the organization in three parts of the lateral collateral ligament and the specific subtalar ligaments: the cervical and the talocalcaneal interosseous ligament. The different injury mechanisms are largely responsible for the sequence of ligament lesions: the most frequent is inversion. The first ligament stabilizers correspond to the cervical and anterior talofibular ligaments; the talocalcaneal ligament, by its oblique orientation, is solicited when there is a dorsal varus-flexion component. In chronic instability, these mechanisms explain the onset of associated lesions (impingement, osteochondral lesions, fibular tendon pathology), which can play a role in instability syndrome. Ligament lesions determine laxity, characteristic of mechanical instability. Functional instability goes along with proprioceptive deficiency. There are postural factors such as varus of the hindfoot that favor instability. Knowledge of all these factors, often associated, will provide a precise lesional assessment and treatment adapted to the instability.

Chronic lateral ankle instability surgical repairs: the long term prospective.

UNLABELLED: The present study sought to assess the clinical and radiological results and long-term joint impact of different techniques of lateral ankle ligament reconstruction. MATERIAL AND METHODS: A multicenter retrospective review was performed on 310 lateral ankle ligament reconstructions, with a mean 13-year-follow-up (minimum FU: 5 years). Male subjects (53%) and sports trauma (78%) predominated. Mean duration of instability was 92 months; mean age at surgery was 28 years. Twenty-eight percent of cases showed subtalar joint involvement. Four classes of surgical technique were distinguished: C1, direct capsular ligamentous complex reattachment; C2, augmented repair; C3, ligamentoplasty using part of the peroneus brevis tendon and C4, ligamentoplasty using the whole peroneus brevis tendon. Clinical and functional assessment used Karlsson and Good-Jones-Livingstone scores; radiologic assessment combined centered AP and lateral views, hindfoot weight-bearing Méary views and dynamic views (manual technique, Telos or self-imposed varus). RESULTS: The majority of results (92%) were satisfactory. The mean Karlsson score of 90 [19-100] (i.e., 87% good and very good results) correlated with the subjective assessment, and did not evolve over time. Postoperative complications (20%), particularly when neurologic, were associated with poorer results. Control X-ray confirmed the very minor progression in degenerative changes, with improved stability; there was, however, no correlation between functional result and residual laxity on X-ray. Unstable and painful ankles showed poorer clinical results and more secondary osteoarthritis. Analysis by class of technique found poorer results in C4-type plasties and poorer control of laxity on X-ray in C1-type tension restoration. DISCUSSION: The present results confirm the interest of lateral ankle ligamentoplasty in the management of instability and protection against secondary osteoarthritis, and of precise lesion assessment (CT-scan/MRI) to adapt surgery to the ligamentary and associated lesions. LEVEL OF EVIDENCE: Level IV. Retrospective therapeutic study.

[Degenerative cartilage changes in metatarsosesamoidal joint and Scarf procedure results for hallux valgus: a prospective study of 100 cases]. / Les lésions cartilagineuses métatarsosésamoïdiennes dans les résultats de l'ostéotomie Scarf: A propos d'une série prospective de 100 cas.

PURPOSE OF THE STUDY: Sesamoid bones of the hallux play a major role in the biomechanics of the metatarsophalangeal complex. Due to the deformations resulting from hallux valgus, the sesamoid system is exposed to abnormal stress forces. Mapping the degenerative cartilage shows the significant prevalence of these lesions and their relation with the anatomic deformation. The purpose of this work was to determine the impact of these metatarsosesamoidal joint changes on the results of Scarf procedure for hallux valgus. MATERIAL AND METHODS: This series included 89 patients (100 feet) who underwent Scarf osteotomy with complementary phalangeal osteotomy. We distinguished two groups in this cohort: 78 cases of surgery not involving the lateral metatarsals (group A), and 22 cases with associated lateral metatarsal osteotomy (group B). Mean follow-up was 2.3 years; minimal follow-up 16 months. The study protocol was prospective, with preoperative and last follow-up radiological and clinical assessment by an independent operator. Joint lesions noted intraoperatively by one senior operator were noted. The clinical work-up included the AOFAS score. A 15 degrees anteroposterior weight-bearing view was used to determine the degree of sesamoid dislocation and measure the following angles: first metatarsophalangeal angle (M1P1), first intermetatarsal space (M1M2), proximal articular set angle (PASA). Eleven zones were described to map the joint surfaces. The statistical analysis was used to search for links between joint lesions and the radiographic and clinical findings. RESULTS: The joint cartilage analysis revealed lesions involving the sesamoid bones in 72 cases, with a preferential involvement of the medial sesamoid bone (67%). The plantar joint surface of the first metatarsal presented lesions in the medial gutter in 72 cases, and in the lateral gutter in 68. Complete absence of the intersesamoid crest was noted in 38%. The metatarsophalangeal compartment presented degenerative lesions in 15 cases. The preoperative assessment noted a positive significant correlation between the AOFAS overall score and the absence of lesions involving the lateral sesamoid bone (p=0.015), between the AOFAS pain score and the absence of lesions involving the lateral sesamoid bone (p=0.022), between the AOFAS pain score and the complete absence of the intersesamoid crest (p=0.001), between the AOFAS deviation score and the absence of lesion involving the lateral gutter (p=0.001), between the M1P1 angle and the absence of an intersesamoid crest (p=0.001). At last follow-up, there was a positive significant correlation between the absence of lesions involving the medial sesamoid bone and a better overall AOFAS score (p=0.014), between absence of a lateral sesamoid lesion and better postoperative sentering of the sesamoids (p=0.014), between the absence of lesion in the medial gutter and a higher postoperative M1P1 angle (p=0.002), between the absence of lesions involving the lateral gutter and more favorable overall AOFAS score (p=0.005) for function (p=0.022), and deviation (p=0.018), between the absence of intersesamoid crest lesions and better radiographic sesamoid recentering (p=0.020). Distinct analysis of groups A and B did not demonstrate a significant difference compared with the overall cohort. Comparison of the two groups only demonstrated three significant differences involving radioclinical parameters. DISCUSSION: Hallux valgus is associated with very frequent metatarsosesamoid lesions. The distribution of these lesions is a function of the anatomic and biomechanical features of the metatarsosesamoid joint surfaces. Lesions to the lateral compartment would be a poor prognostic factor for Scarf procedure.

[Selective dorsal T1-T6 fusion of the thoracic spine and effects on thorax growth: experimental study in prepuberal New Zealand White rabbits]. / Influence de l'arthrodèse vertébrale dorsale sélective T1-T6 sur la croissance thoracique: étude expérimentale chez des lapins New Zealand White prépubertaires.

PURPOSE OF THE STUDY: The purpose of this study is to assess the consequences brought by selective dorsal arthrodesis of thoracic spine (T1-T6) to the growth of spine and thoracic volume in operated and sham-operated New Zealand White rabbits, between prepubertal age and the end of somatic growth, through the study of computerised tomography (CT) scans periodically carried out on them after arthrodesis surgery. MATERIAL AND METHODS: Nine female rabbits were subjected to surgery for selective dorsal arthrodesis of the upper thoracic spine and three were sham-operated. Surgery was performed at age nine weeks, before the onset of puberty. Two "C"-shaped titanium bars were placed beside the spinous processes of the thoracic vertebrae to obtain a selective posterior arthrodesis of the first six thoracic vertebrae. Under general anesthesia, three CT scans were performed, 10 (t1), 55 (t2) and 139 (t3) days after surgery. Measures were obtained by Myrian Pro software for three different groups: group 1 with complete fusion, group 2 with incomplete fusion, group 3 sham-operated. RESULTS: The total dorsal and ventral lengths of thoracic vertebral bodies in the spinal segment T1-T6 was smaller in group 1 and group 2 than in group 3, whereas no differences were observed between the three groups in the T7-T12 segment. The average of the dorsoventral/laterolateral thoracic diameter ratio at fused levels was less than 1 in group 1 as well as in group 2; on the contrary, in group 3 it was greater than 1. The sternum and lung volume grow less. CONCLUSIONS: Vertebral arthrodesis in the treatment of progressive idiopathic scoliosis in prepubertal patients is not ideal, but is still a choice in treating major deformities of the spine. Postoperative assessment of spinal deformity is essential, feasible and recordable through CT scans. Dorsal arthrodesis in prepubertal rabbits changes thoracic growth patterns. In operated rabbits, the dorsoventral thoracic diameter grows more slowly than the laterolateral thoracic diameter. The sternum, the total lengths of thoracic vertebral bodies in the spinal segment T1-T6 and lungs grow less. The Crankshaft phenomenon is evident at the fused vertebral levels where there is a reduction of thoracic kyphosis.

Cortical and trabecular bone distribution in the femoral neck in osteoporosis and osteoarthritis.

The increased hip fragility in osteoporosis has been attributed mainly to a thinning of the cortex. In contrast, hip arthritis (OA) is not associated with increased risk of hip fracture. The purpose of this study was to assess cortical and trabecular bone structures and their possible regional variability in the femoral neck taken from patients who sustained an osteoporotic hip fracture (OP) compared with patients with OA. We compared the distribution of bone in the ultradistal femoral neck in 21 postmenopausal women with OA (mean age: 66+/-7.8 years) and 20 postmenopausal women with an osteoporotic hip fracture (OP) (mean age: 79.5+/-1.9 years). Controlateral hip osteoporosis or osteopenia was confirmed in OP by DEXA (T-score: -2.5+/-0.8 in OP; -0.9+/-1.3 in OA). Histomorphometric parameters of bone structure, architecture and connectivity were measured on sections from the ultradistal part of the femoral neck, divided in 4 quadrants. When compared to OA, cortical thickness was significantly decreased in OP (p<0.0005) but was the highest in the inferior part in both groups. Cortical porosity was higher in OA (13.48+/-1.02 and 8.4+/-1.07% in OA and OP respectively). Compared to OA, the trabecular bone volume was decreased by 50% in OP (p<0.0001) with a diminution of the trabecular number (p<0.01) and thickness (p<0.0001). In parallel, OP group was characterized by a poor connectivity evaluated by the decreased number of nodes (p<0.0001), higher trabecular bone pattern factor (p<0.0001) and greater marrow star volume (p<0.0001). The connectivity was the lowest in the inferior quadrant in OP but not in OA. Our data suggest that in addition to the cortical thinning, the loss of the trabecular bone mass and connectivity plays a role in the skeletal fragility associated with hip fracture. Furthermore, the spatial distribution of the trabeculae differs between OP and OA whereas cortical thinning is homogenous.

[Degenerative changes of the metatarso-sesamoido-phalangeal complex]. / Lésions dégénératives du complexe métatarso-sésamoïdo-phalangien.

OBJECTS: The aim of this work was to determine the frequency and the location of the degenerative lesions of the hallucal metatarsophalangeal joint in an elderly population. Our results help us to precise the anatomic characteristics of that articular complex. METHODS: Our material comprised 21 feet from embalmed cadaver specimens. We studied the morphometrical parameters for the anatomic description of the first metatarsophalangeal joint of the forefoot. After complete dissection, a specific articular zone-mapping was made with a quantitative evaluation of the chondral lesions. MAIN RESULTS: The measurements of the morphometrical parameters were in accordance with the literature data. The sesamoidal chondral lesions were more frequent for the medial sesamoid and at the proximal zone of the articular surface. The plantar metatarsal lesions were very frequent with diffuse or distal groove damage, and crista damage linked to the sesamoidal strap dislocation. The lesions involving the metatarsophalangeal compartment were less frequent and rather at the dorsal zone. CONCLUSIONS: The degenerative lesions of the metatarso-sesamoido-phalangeal complex are nearly systematic in n elderly population. The morphological aspect of these lesions is very characteristic of the articular function and allows us to precise the biomechanic constraints.

[Carpal model and biomechanics]. / Modélisation du carpe osseux et biomécanique.

Carpal morphology and orientation of carpal bones are usually studied on two-plane radiography. Those measurements depend on the incidence of X-ray and on the expertise of physician. A method that eliminates both should improve the accuracy of those measurements. The digital data from computed tomography scans can be use to describe carpal geometry. We defined biometric and angular parameters allowing the study of carpal morphology and bones orientation. From digital data from computed tomography scans software can obtain bone volume, inertia principal axis and volume of ellipsoid of inertia. Bone centroid location and principal axis orientation can be used to study bones orientation. 3D distances ratio between geometry centroid of carpal bones. The measurements allowed by this methodology are numerous. A study of a more consistent series of normal wrists will allow in the future for each quantitative parameter to define the normal range. A comparative study of normal wrists and pathology wrists should allow defining, for each pathology, the most judicious quantitative parameters.

GSB III total elbow replacement in rheumatoid arthritis.

Between 1993 and 2002, 58 GSB III total elbow replacements were implanted in 45 patients with rheumatoid arthritis by the same surgeon. At the most recent follow-up, five patients had died (five elbows) and six (nine elbows) had been lost to follow-up, leaving 44 total elbow replacements in 34 patients available for clinical and radiological review at a mean follow-up of 74 months (25 to 143). There were 26 women and eight men with a mean age at operation of 55.7 years (24 to 77). At the latest follow-up, 31 excellent (70%), six good (14%), three fair (7%) and four poor (9%) results were noted according to the Mayo elbow performance score. Five humeral (11%) and one ulnar (2%) component were loose according to radiological criteria (type III or type IV). Of the 44 prostheses, two (5%) had been revised, one for type-IV humeral loosening after follow-up for ten years and one for fracture of the ulnar component. Seven elbows had post-operative dysfunction of the ulnar nerve, which was transient in five and permanent in two. Despite an increased incidence of loosening with time, the GSB III prosthesis has given favourable mid-term results in patients with rheumatoid arthritis.

[The human body and the computer as pedagogic tools for anatomy: review of the literature]. / Le corps humain et l'informatique comme outils pédagogiques de l'anatomie.

Since the first dissections, the human body has been the main tool for the teaching of anatomy in medical courses. For the last 30 years, university anatomy laboratory dissection has been brought into question and the total hours of anatomy teaching have decreased. In parallel, new technologies have progressed and become more competitive and more attractive than dissection. The aim of this review of the literature was to evaluate the use of the human body as a pedagogic tool compared to today's computer tools. Twenty comparative studies were reviewed. Their analysis showed that the human body remains the main tool in anatomy teaching even if anatomic demonstration (prosection) can replace dissection, and that the computer tools were complementary but not a substitute to dissection.

Study of carpal bone morphology and position in three dimensions by image analysis from computed tomography scans of the wrist.

The morphology and positioning of the carpal bones were studied in three dimensions in 18 normal adults on computed tomography (CT) scans of the wrist. The digital data from each CT scan were processed to extract the carpal bones and to automatically characterize their geometry (geometric centroid, principal axes of inertia) using specific software tools. Biometric and angular parameters were defined for this purpose, and most of these parameters showed a normal distribution. The mean distance between the geometric centroid of the capitate and that of the triquetrum, expressed as a relationship to the length of the first principal axis of inertia of the capitate, was found to be the greatest (157.6%+/-8.4%), whereas the smallest mean distance was between the hamate and triquetrum (91.4%+/-7.3%). In the sagittal plane, the first principal axis of inertia of the bones of the first carpal row projected in front of the vertical axis of the orthogonal reference system, whereas the first principal axis of the capitate projected behind it. Measurements using this methodology are far more numerous than those from standard plain radiographs and have the additional advantage of being independent of the examiner. Future investigations on normal wrists should provide a normal range for each quantitative parameter, and comparative study of normal and pathologic wrist measurements should help to define the most relevant parameters for specific traumatic pathologies of the wrist.

Plagiocephaly: morphometry of skull base asymmetry.

The aim of this study was to perform a morphometric analysis of the skull base to understand the mechanism of asymmetry between malformational and deformational plagiocephaly. Since 1988, we have carried out 102 CT scans with three-dimensional reconstruction of the endocranial side of the skull base. There were 20 cases of malformational plagiocephaly, consisting of 18 unicoronal synostoses (UCS) and two unilambdoid synostoses (ULS), and 82 cases of plagiocephaly without synostosis, made up of 60 cases of frontal plagiocephaly (FP) and 22 of occipital plagiocephaly (OP). The skull base asymmetry was analyzed in three ways: (1) the hemibases and the cranial fossa angles were compared with each other; (2) the structural asymmetry of the chondrocranium was calculated; and (3) the architectural asymmetry was measured in relation to the medio-labyrinthine plane. The skull base asymmetry of malformational plagiocephaly was located in the anterior and middle cranial fossae for UCS and in the posterior and middle cranial fossae for ULS. The asymmetry was the result of a localized structural anomaly of the chondrocranium. The asymmetry of deformational plagiocephaly corresponded to a distortion in relation to the medio-labyrinthine plane while the chondrocranium remained symmetric. The skull base asymmetry of malformational plagiocephaly is secondary to a localized malformation of the chondrocranium, and that of the deformational plagiocephaly is secondary to an architectural deformation.

[Clinico-radiological study of the skull deformation in the plagiocephaly without synostosis]. / Etude clinico-radiologique des déformations du crâne dans les plagiocéphalies sans synostose.

UNLABELLED: The aim of this study was to analyze the mechanism of the skull deformation observed in frontal and occipital plagiocephaly without synostosis. POPULATION AND METHODS: From 1987 to 2001, 96 plagiocephalies without synostosis, 72 males and 24 females, were examined. There were 72 Frontal Plagiocephalies (FP) and 24 Occipital Plagiocephalies (OP). The clinical examination of the neck muscles was performed to find out a torticolis with or without retraction. All patients underwent a 3D CT scan of the skull to exclude a craniostenosis. Cephalic Index (CI) was also calculated. RESULTS: The FP had a torticollis in 89.3% of cases associated with a muscle retraction (54.8%), a tonus asymmetry (16.6%), or in association (28.6%). The skull had a parallelepiped shape and the greater axis was oblique. The CI was 0.85. The OP had a torticollis in 50% of case associated with a retraction (28.6%), a tonus asymmetry (57.1%), or the association (14.3%). The skull had a square shape with an occipital flat and the CI was 0.95. DISCUSSION: The FP and OP are two deformations whose mechanism is different. The FP corresponds to a three plans skull asymmetry secondary to muscle traction on the base of the skull, and the OP corresponds to a posterior localized asymmetry of the skull secondary to compression. CONCLUSION: The traction and/or compression deformation start in utero or in the newborn period and the supine position is an aggravating positional factor.

Biometry of the radial head: biomechanical implications in pronation and supination.

The aim of this study was to perform biometry of the proximal extremity of the radius and to characterize the shape of the radial head. Knowledge of the size and shape of the radial head is necessary for the creation of a radial head prosthesis that is anatomically and biomechanically correct. Twenty-seven measurements, focused on the proximal extremity, were done on 96 radii. The shape of the radial head was determined by the difference between the maximum diameter and the minimum diameter. We considered the shape to be circular when the difference was less than 1 mm, and elliptical when the difference was greater than 1 mm. The shape of the radial head was compared with the neck/diaphysis angle. Fifty-seven percent of radial heads were elliptical and 43% were circular. When the head was elliptical the maximum diameter was 22 mm +/-2.9 and the minimum diameter was 20 mm +/-2.8 ( P<0.001). When the head was circular the maximum diameter was 21.2 mm +/-2.4 and the minimum diameter was 20.4 mm +/-2.4 ( P<0.14). The angle between the neck and the diaphysis varied with regard to the shape of the radial head. It was 166.75 degrees +/-3 for the circular heads and 168.62 degrees +/-3.2 for the elliptical heads ( P<0.01). The biomechanics of the circular shape and the elliptical shape are different, involving an adaptation of the angle between the neck and the radial diaphysis. This difference must be taken in consideration in the design of a radial head prosthesis.

[Interpretation of thoracic radiographs re-examined and corrected with tomodensitometry]. / L'interprétation d'une radiographie thoracique revue et corrigée par la tomodensitométrie.

To our knowledge, conventional chest radiography is not likely to become obsolete or disappear from the daily practice of medical imaging. As such, it is important to insure that chest radiographs are acquired using optimal technique. Evaluation of chest radiograph findings must be comprehensive and the art of reading chest radiographs must be well thought to physicians in training. Chest radiography is characterized by the projection of tridimensional anatomical structures and disease processes onto a two-plane radiographic film. Correlation with cross-sectional data obtained from CT may greatly enhance the understanding and interpretation of conventional chest radiographs. Indeed, review of CT images facilitates anatomical understanding of the segmental and subsegmental anatomy, of the superior segments of the lower lobes and of the three dimensional orientation of the fissures. CT also has improved the understanding of some chest radiography findings. Careful review of findings at chest radiography is helpful to optimize CT acquisition protocols in order to reduce some of the pitfalls of CT and improve detection of specific processes that could otherwise be poorly demonstrated or overlooked. Chest radiographs can sometimes detect diseases or abnormalities that are difficult to demonstrate at CT.