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C Tardieu

Publications and source records attributed to C Tardieu.

At least 19 recordsLinked to original sources
PubMed2006

Relationship between formation of the femoral bicondylar angle and trochlear shape: independence of diaphyseal and epiphyseal growth.

During hominin evolution, an increase in the femoral bicondylar angle was the initial change that led to selection for protuberance of the lateral trochlear lip and the elliptical profile of the lateral condyle. No correlation is found during ontogeny between the degree of femoral obliquity and of the prominence of the lateral trochlear lip. Might there be a relationship with the elliptical profile of the lateral condyle? On intact femoral diaphyses of juvenile humans and great apes, we compared the anteroposterior length of the lateral and medial sides of the distal metaphysis. The two diaphyseal pillars remain equal during postnatal growth in great apes, while the growth of the lateral pillar far exceeds that of the medial pillar in humans. Increase in bicondylar angle is correlated with disproportionate anteroposterior lengthening of the lateral pillar. The increased anteroposterior length of the lateral side of the metaphysis would contribute to increasing the radius of the curvature of the lateral condyle, but not to the projection of the lateral trochlear lip. The similar neonatal and adult femoro-patellar joint shape in humans prompted an assessment of the similarity during growth of the entire neonatal and adult epiphyses. We showed that the entire epiphysis undergoes drastic changes in proportions during postnatal growth. Finally, we emphasize the need to distinguish the cartilaginous phenotype and the ossified phenotype of the distal femoral epiphysis (and of any epiphysis) during postnatal growth. This crucial distinction applies to most postcranial bones, for they almost all develop following the process of endochondral ossification.

Adaptation, Physiological↗
PubMed2005

Sagittal alignment of spine and pelvis regulated by pelvic incidence: standard values and prediction of lordosis.

Pelvis and spinal curves were studied with an angular parameter typical of pelvis morphology: pelvic incidence. A significant chain of correlations between positional pelvic and spinal parameters and incidence is known. This study investigated standards of incidence and a predictive equation of lordosis from selective pelvic and spinal individual parameters. One hundred and forty nine (78 men and 71 women) healthy adults, aged 19-50 years, with no spinal disorders, were included and had a full-spine lateral X-ray in a standardised upright position. Computerised technology was used for the measurement of angular parameters. Mean-deviation section of each parameter and Pearson correlation test were calculated. A multivariate selection algorithm was running with the lordosis (predicted variable) and the other spinal and pelvic parameters (predictor variables), to determine the best sets of predictors to include in the model. A low incidence (<44 degrees ) decreased sacral-slope and the lordosis is flattened. A high incidence (>62 degrees ) increased sacral-slope and the lordosis is more pronounced. Lordosis predictive equation is based on incidence, kyphosis, sacral-slope and +/-T9 tilt. The confidence limits and the residuals (the difference between measured and predicted lordosis) assessed the predicted lordosis accuracy of the model: respectively, +/-1.65 and 2.41 degrees with the 4-item model; +/-1.73 and 3.62 degrees with the 3-item model. The ability of the functional spine-pelvis unit to search for a sagittal balance depended both on the incidence and on the variation section of the other positional parameters. Incidence gave an adaptation potential at two levels of positional compensation: overlying state (kyphosis, T9 tilt), underlying state (sacral slope, pelvic tilt). The biomechanical and clinical conditions of the standing posture (as in scoliosis, low back pain, spondylisthesis, spine surgery, obesity and postural impairments) can be studied by comparing the measured lordosis with the predicted lordosis.

Adult↗
PubMed2003

[Anatomic study of the anterior patellar groove in the fetal period].

PURPOSE OF THE STUDY: We performed a biometric analysis of the femoral trochlea in the fetus and compared our findings with those observed in adults in order to search for correlations with other biometric parameters of the femur. MATERIAL AND METHOD: Twenty-two fetuses (44 knees) conserved in formol and free of known orthopedic disease were studied. Fetal age ranged from 26 to 40 weeks. After anatomic dissection, digitalized images were used to obtain angle measurements with a dedicated software. Measurements made on the distal epiphyseal view were: anteroposterior dimension of the condyles, medial and lateral protrusion of the trochlear borders, difference in condyle height, length of the trochleal borders, alpha angle of the trochlear groove, trochlear slope. Measurements made on the AP femoral view were: femoral anteversion, length of the femoral neck, neck-shaft angle. Spearman's test was used to search for correlations. Results were compared with measurements obtained under the same conditions in a series of 32 adult knees published by Wanner. RESULTS: The trochlear alpha angle was 148 degrees (coefficient of variation 4%). The angle was greater than 150 degrees for 18 trochleae. The lateral border of the trochela was higher than the medial border in 37 of the 44 knees. There was no correlation with age and gender. Femoral anteversion was 27.01 degrees, with a high coefficient of variation (46%), and no correlation with the trochlear alpha angle. Comparison with measurements made on the adult knees revealed no significant difference. DISCUSSION: This is the first report of statistically significant biometric data of the fetal trochlea. The morphology of the lower femur observed during the third trimester of fetal live is the same as observed in adults. Morphological changes in the proximal femur occurring during growth do not appear to modify the morphology of the distal femur. The asymmetrical ingression of the patella into the trochlea, characteristic of modern man, is considered to result from bipedalism. Our study would suggest that the anatomic characteristics of the trochlea could have been integrated into the genoma during the course of evolution. This would be in favor of a genetic origin of trochlear dysplasia.

Adult↗
PubMed2002

Development of the femoral bicondylar angle in hominid bipedalism.

The bicondylar angle is the angle between the diaphysis of the femur and a line perpendicular to the infracondylar plane. The presence of a femoral bicondylar angle in Australopithecus afarensis indicates that these 3.5-million-year-old hominids were bipedal. Many studies have linked the formation of the femoral bicondylar angle with bipedality, but the mechanism for the formation of the angle is poorly understood. Mechanical factors, such as stresses and strains, influence the growth process. In particular, previous studies have demonstrated that hydrostatic compressive stress inhibits growth and ossification, and octahedral shear stress promotes growth and ossification. In this study we implemented these mechanobiological principles in a three-dimensional finite-element model of the distal femur. We applied loading conditions to the model to simulate loading during the single-leg stance phase of bipedal gait. The stresses in the physis of the distal femur that result from bipedal loading conditions promote growth and ossification more on the medial side than on the lateral side of the femur, forming the bicondylar angle. This model explains the presence of the bicondylar angle in hominid bipedalism and also the ontogenetic development of the bicondylar angle in growing children. The mechanobiological relationship between endochondral ossification and mechanical loading provides valuable insight into bone development and morphology.

Animals↗
PubMed2001

[The origin of femoral trochlear dysplasia: comparative anatomy, evolution, and growth of the patellofemoral joint].

We performed a comparative analysis of the femoropatellar morphology examining the evolutionary aspects to search for the origin of trochelar dysplasia. Trochlear dysplasia is frequent in the human population and, when associated with morphological and positional abnormalities of the patella, can lead to patellar pain syndrome in minor cases or patellar dislocation in severe cases. There is no strict relationship between the observed anomalies and clinical expression. The shape of the articular surfaces is variable in mammals depending on their type of locomotion: unguligrade, digitigrade, plantigrade. In greater apes, the femoral diaphysis is straight and the trochlea is flat and symmetrical. The patella does not tend to dislocate laterally since the knee under load is always flexed. In human adults, the femoral diaphysis has a valgus obliquity angle of 8 degrees to 10 degrees. Consequently, the trochlea has a deepened sulcus and an elevated lateral lip, avoiding lateral patellar dislocation, especially during initial knee flexion. In the human newborn, the femoral diaphysis is vertical. As the child starts walking, the femoral obliquity angle develops between 1 and 7 years of age, inducing a secondary valgus of the extensor apparatus. This obliquity does not develop in non-walking children. Fossil femurs of australopithecus demonstrate that a high obliquity angle had appeared more than 3 million years ago, but also exhibit a poorly deepened trochlea and a slight elevation of the lateral facet. At 1.8 million years, the fossils have the oblique diaphysis, the strongly deepened sulcus and the strongly elevated lateral facet. The obliquity angle of the femoral diaphysis is the leading feature which initiated the later modifications of the patellofemoral joint that over 3 million years were never inscribed in the human genoma. Lateral trochleal lip and deep sulcus are features that were first acquired, then once selected, genetically assimilated, and now appear on the fetal cartilaginous epiphysis.

Adult↗
PubMed1999

Ontogeny and phylogeny of femoro-tibial characters in humans and hominid fossils: functional influence and genetic determinism.

Three different human femoro-tibial characters are selected as functionally relevant and derived hominid characters: femoral bicondylar angle, shape of the femoral distal epiphysis, and the tibial insertion of the lateral meniscus. The timing and mode of formation of these characters are investigated during human ontogeny and are shown to differ considerably. The available hominid fossils (Australopithecus afarensis and early Homo) are interpreted in the light of this ontogenetic analysis with the conclusion that, during hominid evolution, different modes of selection of these features must have occurred. In modern humans, the femoral bicondylar angle proves to be an epigenetic functional feature, which develops during early childhood growth. It is present in all australopithecines and we suggest that it developed following a change in their locomotor behavior and not upon a genomic change: the early practice of bipedal walking, with adducted knee joints, in the locomotor repertoire of infant australopithecines, was sufficient to promote this angle. Later in hominid evolution, the knee joint evolved from having a single insertion of the lateral meniscus on the tibia to a double one. While Australopithecus afarensis exhibits a single insertion, early Homo clearly exhibits a double insertion of the lateral meniscus on the tibia. The double insertion restricts the mobility of the meniscus on the tibial plateau, indicating a habitual practice of full extension movements of the knee joint. Among modern humans, the posterior insertion of the lateral meniscus appears early in fetal life. Consequently in early Homo, this new selected feature developed directly as a result of a genomic change. The derived shape of human distal femoral epiphysis includes a prominence of the lateral lip of the femoral trochlea, an elliptical profile of the lateral condyle, and an anteroposterior lengthening of the epiphysis. Analysis of human fetal and neonatal distal epiphyses shows that the prominence of the lateral lip of the trochlea arises before any use, and thus appears to be genetically determined. However, the postnatal development of this joint shows that this feature is also modified epigenetically by use. It is argued that the hominid femoro-patellar joint would have been reshaped following the process of genetic assimilation (Waddington [1942] Nature 3811:563-565). The prominence of the lateral lip of the femoral trochlea was probably selected following a two-staged process-first epigenetic, then genetic. Far from being a Lamarckian explanation, this concept applies precisely to adaptive characters that are induced by an external stimulus during a single lifetime and are replaced through natural selection by genetically based equivalent characters. The nature of the structures involved in the studied features is shown to be an important parameter determining their mode of development and selection.

Adaptation, Physiological↗
PubMed1999

Low-energy He/Ne laser in the prevention of radiation-induced mucositis. A multicenter phase III randomized study in patients with head and neck cancer.

Use of the low-energy helium-neon laser (LEL) appears to be a simple atraumatic technique for the prevention and treatment of mucositis of various origins. Preliminary findings, and significant results obtained for chemotherapy-induced mucositis in a previous phase III study, prompted a randomized multicenter double-blind trial to evaluate LEL in the prevention of acute radiation-induced stomatitis. Irradiation by LEL corresponds to local application of a high-photon-density monochromatic light source. Activation of epithelial healing for LEL-treated surfaces, the most commonly recognized effect, has been confirmed by numerous in vitro studies. The mechanism of action at a molecular and enzymatic level is presently being studied. From September 1994 to March 1998, 30 patients were randomized. Technical specification: 60 mW (25 mW at Reims, 1 patient), He-Ne, wavelength 632.8 nm. The trial was open to patients with carcinoma of the oropharynx, hypopharynx and oral cavity, treated by radiotherapy alone (65 Gy at a rate of 2 Gy/fraction, 5 fractions per week) without prior surgery or concomitant chemotherapy. The malignant tumor had to be located outside the tested laser application areas (9 points): posterior third of the internal surfaces of the cheeks, soft palate and anterior tonsillar pillars. Patients were randomized to LEL or placebo light treatment, starting on the first day of radiotherapy and before each session. The treatment time (t) for each application point was given by the equation : t(s)= energy (J/cm2) x surface (cm2)/Power (W). Objective assessment of the degree of mucositis was recorded weekly by a physician blinded to the type of treatment, using the WHO scale for grading of mucositis and a segmented visual analogue scale for pain evaluation. Protocol feasibility and compliance were excellent. Grade 3 mucositis occured with a frequency of 35.2% without LEL and of 7.6% with LEL (P<0.01). The frequency of "severe pain" (grade 3) was 23.8% without LEL, falling to 1.9% with LEL (P<0.05). Pain relief was significantly reduced throughout the treatment period (weeks 2-7). LEL therapy is capable of reducing the severity and duration of oral mucositis associated with radiation therapy. In addition, there is a tremendous potential for using LEL in combined treatment protocols utilizing concomitant chemotherapy and radiotherapy.

Adult↗
PubMed1998

Short adolescence in early hominids: infantile and adolescent growth of the human femur.

Did the first hominids have a short developmental period similar to that of the great apes or a longer period closer to that of modern humans? Evidence from studies on dental and facial growth favors the first point of view. Additional evidence presented in this report is provided by a morphogenetic analysis of the lower limb. Some morphological modifications undergone by the human femur during infantile and adolescent growth are shown to be excellent markers of different developmental stages. The angular remodelling of the femoral diaphysis, which results in femoral bicondylar angle, is a marker of infancy, while the reshaping of the distal femoral epiphysis is a marker of adolescence. This reshaping of the bony epiphysis consists of the strong projection of the external lip of the femoral trochlea, the increase of the radius of curvature of the external condyle, and the anteroposterior lengthening of the whole epiphysis. The growth spurt in linear dimensions of the femur, characteristic of human adolescence, is shown to be associated with qualitative changes of the distal femoral epiphysis engendered by the late closure of the distal epiphysis. The femur of the first hominids (Australopithecus afarensis) shows only features of infantile growth, whereas characters of both precocious and later growth are typical of later hominids (Homo). The absence of the derived epiphyseal features in Australopithecus would be linked to their early epiphyseal closure and short adolescent growth period; their presence in Homo would have been promoted by their delayed epiphyseal closure and prolonged adolescent growth period. The transition from Australopithecus to Homo appears to have involved a heterochronic process of time hypermorphosis (Gould, [1977], Ontogeny and Phylogeny [Cambridge: Harvard University Press]) in which the size of the femur increases, the epiphysis is modified, and the period of peripubertal growth is prolonged. The shape of the distal epiphyses of KNM-WT 15000, an immature Homo erectus (Brown et al. [1985] Nature 316:788-792), lies clearly within the range of modern human adolescents. In contradiction to Smith's ([1993] in A. Walker and R. Leakey [eds.]: The Nariokotome Homo erectus Skeleton [Cambridge: Harvard University Press], pp. 195-220) hypothetical reconstruction of life span of Homo erectus, we infer that a growth spurt had begun with Homo erectus but was probably less pronounced and of shorter duration than in modern humans. Our findings on the femur are consistent with studies of the growth on the hominid pelvis (Berge [1996] in LF Marcus, M Corti, A Loy, G Naylor, and DE Slice [eds.]: Advances in Morphometrics [Chicago: Plenum Publishing Corp.], pp. 441-448). It is suggested that the lengthening of the adolescent growth period, from Australopithecus to Homo, would have been also associated with the shape changes of the pelvis and with the lengthening of the lower limbs.

Adolescent↗
PubMed1997

Low energy Helium-Neon laser in the prevention of oral mucositis in patients undergoing bone marrow transplant: results of a double blind randomized trial.

PURPOSE: To evaluate the efficiency of Helium-Neon (He-Ne) laser in the prevention of oral mucositis induced by high dose chemoradiotherapy before autologous bone marrow transplantation (BMT). METHODS AND MATERIALS: Between 1993 and 1995, 30 consecutive patients receiving an autologous peripheral stem-cell or bone marrow transplant (BMT) after high dose chemoradiotherapy were randomized to possibly receive prophylactic laser to the oral mucosa after giving informed consent. Chemotherapy consisted of cyclophosphamide, 60 mg/kg intravenously (I.V.) on day (d)-5 and d-4 in 27 cases, or melphalan 140 mg/kg I.V. on d-4 in three cases. Total body irradiation (TBI) consisted of 12 Gy midplane dose in six fractions (4 Gy/day for three days). He-Ne laser (632.8 nm wavelength, power 60 mW) applications were performed daily from d-5 to d-1 on five anatomic sites of the oral mucosa. Oral examination was performed daily from d0 to d + 20. Mucositis was scored according to an oral exam guide with a 16 item scale of which four were assessed by the patients themselves. Mean daily self assessment scores for oral pain, ability to swallow and oral dryness were measured. A daily mucositis index (DMI) and a cumulative oral mucositis score (COMS) were established. Requirement for narcotics and parenteral nutrition was recorded. RESULTS: The COMS was significantly reduced among laser treated (L+) patients (p = 0.04). The improvement of DMI in L+ patients was also statistically significant (p < 0.05) from d + 2 to d + 7. Occurrence and duration of grade III oral mucositis were reduced in L+ patients (p = 0.01). Laser applications reduced oral pain as assessed by patients (p = 0.05) and L+ patients required less morphine (p = 0.05). Xerostomia and ability to swallow were improved among the L+ patients (p = 0.005 and p = 0.01, respectively). Requirement for parenteral nutrition was not reduced (p = NS). CONCLUSION: Helium-Neon laser treatment was well tolerated, feasible in all cases, and reduced high dose chemoradiotherapy-induced oral mucositis. Optimal laser treatment schedules still needs to be defined.

Adolescent↗
PubMed1997

Helium-neon laser irradiation is not a stressful treatment: a study on heat-shock protein (HSP70) level.

BACKGROUND AND OBJECTIVE: Helium-neon (He-Ne) laser irradiation has been clinically used to reduce chemotherapy-induced mucositis. This work was designed to find out if this treatment is stressful at the cellular level by studying its effects on the level of the stress-inducible heat shock proteins. STUDY DESIGN/MATERIALS AND METHODS: Human desmodontal and mouse L929 fibroblasts were irradiated using a 60 mW laser by a single application of 1.5 and 3J/cm2 in continuous mode. Heat shock protein level was studied by gel electrophoresis and Western blotting using monoclonal antibodies. RESULTS: He-Ne treatment does not induce heat shock protein synthesis in human desmodontal nor in mouse fibroblasts at the energy densities used in this study. CONCLUSIONS: These results indicate that the treatment is not stressful at the cellular level.

Animals↗
PubMed1997

Comparison of the intraosseous biocompatibility of Dyract and Super EBA.

The purpose of this study was to compare the intraosseous biocompatibility of Dyract, a new hydrophilic glass-ionomer cement, to that of Super EBA. Twenty-four New Zealand rabbits were anesthetized, one leg was shaved, the femur exposed, and two holes were drilled through the cortical plate. The materials were loaded into silicone carriers and inserted into the femur. Half of the rabbits were killed 4 weeks after implantation and the other half at 12 weeks and the femurs were prepared using standard histological procedures. The tissue reactions were graded from none to severe. At 4 weeks both materials showed slight to moderate reactions, characterized by the presence of fibrous tissue interposition and inflammatory cells. At 12 weeks, bone healing had occurred, despite the persistence of some fibrous tissue interposition, and the reactions were classified as slight. At both observation periods, statistical analysis failed to show any difference between the two materials indicating that Dyract and Super EBA had similar intraosseous biocompatibility.

Animals↗
PubMed1997

In vitro cytotoxicity of dental adhesive systems under simulated pulpal pressure.

OBJECTIVES: Most of the devices used to evaluate the cytotoxicity of resin-based composites in vitro use a dentin barrier test. However, it is difficult to obtain the number of freshly extracted teeth, all on the same day, that is necessary for powerful statistical analysis. Tooth cryopreservation provides a way to build up a supply of teeth. This in vitro study compared cryopreserved teeth and freshly extracted teeth in an evaluation of the cytotoxicity of resin-based composites. In addition, this study also evaluated the effects of pulsatile pressure and the importance of dentin permeability on the cytotoxic response to bonding resins. METHODS: Forty freshly extracted and forty cryopreserved third molars were used. A standardized Class I cavity was prepared within the dentin. The hydraulic conductance of each tooth was recorded. The cavities were filled either with Scotchbond Multi-Purpose Plus and Z 100 (3M Dental Products) or with Optibond and Herculite (Kerr). A plexiglas device was designed to permit 24 h long contact between culture medium and the roof of the pulp chamber while a pulsatile pulpal pressure was simulated. The viability of L 929 cells cultured with a control medium and evaluated by an MTT assay was compared to that of L 929 cells cultured with medium which remained for 24 h in contact with the pulp chamber of restored teeth. A three-way ANOVA was used to compare the cytotoxicity among the different groups. A simple least-squares linear regression was used to seek a relationship between the hydraulic conductance of dentin and the cytotoxicity of composite restorative materials. RESULTS: No significant differences in cytotoxicity were found between the freshly extracted teeth and the cryopreserved teeth (p = 0.53). The cytotoxicity of the resin adhesives was statistically higher when a pulsatile pulpal pressure was simulated (p = 0.04). A significant relationship was found between the hydraulic conductance of dentin and the cytotoxicity of resin-based composites (p = 0.02). SIGNIFICANCE: Cryopreserved teeth can be used for in vitro evaluation of the cytotoxicity of resin adhesives. Pulsatile pulpal pressure simulations increased the in vitro cytotoxicity of the tested materials.

Adult↗
PubMed1997

Evolution of the angle of obliquity of the femoral diaphysis during growth--correlations.

Numerous studies of the bicondylar angle of the adult femur have been carried out in human anatomy, paleoanthropology and primatology. The aim of this paper is to study the evolution of this angle in relation to age and acquisition of walking in young children. Seventy-seven radiographs of children, ranging from 5 months to 17 years postnatally, and of four dead newborn were analysed. The measurements concern the bicondylar angle (A.O.F.), the collo-diaphyseal angle (A.C.D.), the length of the femoral neck (L.N.) and of the femur (L.F.) and the interacetabular distance (D.I.A.). Some children were x-rayed at different ages, which permits a longitudinal as well cross-sectional study. The results show that there is no sexual dimorphism and that the increase in the angle is closely related to the age of the child. The bicondylar angle starts at 0 degree at birth and then increases progressively with growth to reach adult values of at least 6 degrees-8 degrees between 4 and 8 years postnatally. In adults, the mean values are between 8 degrees and 11 degrees and the maximum range is between 6 degrees and 14 degrees. The obliquity angle corresponds to an angular remodeling of the femoral diaphysis, which is independent of the growth and shape of the distal femoral epiphysis. The tibio-femoral angle measures the evolution of a physiologic phenomenon, from the load "in varus" to the load "in valgus" of the lower limb. It is linked with the bicondylar angle but is different from it.

Adolescent↗
PubMed1996

Quantitative scale of oral mucositis associated with autologous bone marrow transplantation.

Acute oral complications are serious and disabling secondary effects for patients undergoing cancer therapy. Therefore, the authors wanted to develop a sensitive and specific method to measure oral mucosal changes associated with autologous with autologous bone marrow transplantation. 14 patients, all volunteers, 18-56 years old, receiving conditioning regimens of cyclophosphamide and total body irradiation were included. The clinical changes of the oral mucosa and functional modifications were scored daily, over 21 days with a 16 item scale, ranging from 0 to 3. A daily index of mucositis (DIM) was established by adding the scores obtained for the 16 items and a cumulative score of oral mucositis was obtained by the addition of the 21 DIM for assessing the severity of oral mucositis throughout its duration. The internal consistency measures (Chronbach alpha) were strong (range 0.80-0.97). A scale of equivalence, pre-established in comparison with pre-existing general mucositis rating scales, permitted a day by day simple classification in a 4-grade scale, to be obtained. Support for the validity of the suggested scale is presented. This scale may help to improve the study of oral complications of cancer therapy.

Adolescent↗
PubMed1996

Ontogeny of the knee joint in humans, great apes and fossil hominids: pelvi-femoral relationships during postnatal growth in humans.

Results of a study of the femoral bicondylar angle in adult and juvenile humans and great apes are presented. These results raise the question of whether or not the measurement reference of this angle is valid. This is because humans and great apes have a very different growth process of the distal epiphyseal suture of the femur during the period between birth and adulthood. The approximately 3 million years old juvenile femoral diaphyses attributed to Australopithecus afarensis (AL 333-110 and AL 333-111) were also studied. These specimens show an insertion of the diaphysis into the epiphysis of the simplified type typical of modern humans. This region is more convoluted in nonhuman anthropoids. Pelvifemoral interrelations are investigated through both longitudinal and cross-sectional radiographic studies of 23 human children. Growth changes in bicondylar and collo-diaphyseal angles, total femoral and femoral neck lengths, and interacetabular distance are correlated with age and to each other. These results are used to demonstrate the distinctive features of the Australopithecus afarensis fossil, AL 288-1.

Adult↗
PubMed1996

Biomechanical reasons for the divergent morphology of the knee joint and the distal epiphyseal suture in hominoids.

The obliquity of the femoral diaphysis accounts for the valgus position of the human knee joint and reduces bending moments in the frontal plane. A high angle of obliquity is considered a hallmark of hominid bipedality, but its functional importance has rarely been identified correctly. A biostatic investigation of the knee joint in various realistic positions unveils resultant joint forces which do not deviate greatly from the long axis of the femoral shaft. This is due to the length of the femur and to the shortness of the human foot. The flat epiphyseal suture is more or less perpendicular to these joint forces, and the equal size of the femoral condyles reflects the even distribution of forces between them. In great apes the resultant forces acting in the knee joint vary considerably in dependence on the degree of flexion and rotation of the knee joint. The resultant joint force may be line with the femur shaft or diverge. The epiphyseal surfaces offer facets to all joint forces found in the course of the study. Due to the pronounced varus position of the knee joint, the joint itself and the adjacent part of the femur are under medially concave bending moments, which lead to higher compressive forces at the medial than at the lateral condyle. The enlarged medial condyle allows the distribution of medially displaced joint forces over a relatively large area, and the elliptic cross-section yields high bending resistance in the frontal plane. A human-like angle of obliquity is present in the early australopithecines, the values being mostly within the range of variation of children. The valgus position of the australopithecine knee joint is considered to be a functional, and epigenetic consequence of habitual bipedality. It is particularly pronounced because of the short length of the femur and the great bitrochanteric width.

Animals↗
PubMed1994

Early ontogeny of the human femoral bicondylar angle.

The presence of a femoral bicondylar angle consistently and significantly greater than 0 degrees has been a hallmark of hominid bipedality, but its pattern of development has not been documented. We have therefore compiled cross-sectional data on the development of the articular bicondylar angle for a clinical sample of modern humans and of the metaphyseal bicondylar angle for two Recent human skeletal samples, one predominantly European in origin and the other Amerindian. All three samples exhibit a pattern of a bicondylar angle of 0 degrees at birth and then a steady average increase in the angle from late in the first year postnatal, through infancy; and into the juvenile years. The two skeletal samples reach low adult values by approximately 4 years postnatal, whereas the clinical sample with a lowered activity level appears to attain consistent adult values slightly later (approximately 6 years postnatal). In addition, two modern human individuals, one nonambulatory and the other minimally ambulatory, show no and little development, respectively, of a bicondylar angle. These data, in conjunction with clinical and experimental observations on the potential and form of angular changes during epiphyseal growth, establish a high degree of potential for plasticity in the development of the human bicondylar angle and the direct association of a bipedal locomotion and (especially) posture with the developmental emergence of a human femoral bicondylar angle.

Adolescent↗