Bruno Baillon

In vitro biomechanical study of femoral torsion disorders: Effect on femoro-tibial kinematics

BACKGROUND Gonarthrosis is a degenerative disease mainly found in elderly persons. Frontal plane deviations are known to induce lateral and medial gonarthrosis. Nevertheless, patients suffer from gonarthrosis without frontal deviations. Lower limb torsions disorders have been considered as a factor inducing lateral and medial gonarthrosis. This paper reports an in vitro study aiming at quantifying the relationships between experimental femoral torsion disorders and femoro-tibial kinematics. METHODS Five fresh-frozen lower limbs were used. Specimens were fixed on an experimental jig and muscles were loaded. A six-degree-of-freedom Instrumented Spatial Linkage was used to measure femoro-tibial kinematics. Experimental femoral osteotomies were performed to simulate various degrees of medial and lateral torsion. Internal tibial rotation, abduction/adduction and proximo-distal, medio-lateral and antero-posterior translations were measured during knee flexion. FINDINGS Internal tibial rotation and abduction/adduction were significantly influenced (P<0.001) by femoral torsion disorder conditions. Medial femoral torsion increased tibial adduction and decreased internal rotation during knee flexion. Opposite changes were observed during lateral femoral torsion. Concerning translations, medial femoral torsion induced a significant (P<0.05) decrease of medial translation and inversely for lateral femoral torsion. No interactions between femoral torsion disorders and range of motion were observed. INTERPRETATION Our results showed that medial and lateral femoral torsion disorders induced alterations of femoro-tibial kinematics when applied in normally aligned lower limbs. These results highlight a potential clinical relevance of the effect of femoral torsion alterations on knee kinematics that may be related to the development of long-term knee disease.

Modifications de la cinématique du genou et des bras de levier du quadriceps et des ischio-jambiers après ostéotomie tibiale haute « curviplane » de valgisation ou de varisation : Étude in vitro

Resume Les modifications de cinematique du genou, des bras de levier des muscles quadriceps et des ischio-jambiers induites par une deviation en valgus ou en varus du tibia ont ete etudiees sur cinq preparations anatomiques de membres inferieurs non fixes. Une osteotomie tibiale haute « curviplane » a permis d’appliquer des deviations frontales. Deux electrogoniometres a six degres de liberte ont ete utilises pour l’etude des cinematiques. Les excursions tendineuses des muscles etudies ont ete mesurees par des LVDT ( linear variable differential transformer ) et ont permis en combinaison avec les donnees de l’electrogoniometre de calculer les bras de levier musculaires. Nos resultats ont demontre que l’osteotomie « curviplane » engendre une deformation tridimensionnelle du tibia et des modifications significatives des bras de levier du quadriceps et du semi-tendineux. La deviation en varus induit une rotation interne du tibia et de la rotule, inversement pour la valgisation. La deformation en varus ne modifie pas la valeur maximale du bras de levier du quadriceps mais celle-ci survient pour un angle de flexion du genou plus eleve. En outre, la valeur moyenne du bras de levier du muscle semitendinosus est reduite. La deviation en valgus accroit la valeur maximale du bras de levier du quadriceps. La valeur moyenne du bras de levier du muscle semitendinosus est egalement accrue. Les modifications induites par la valgisation seraient donc favorables a la physiologie articulaire du genou.

In vitro biomechanical study of femoral torsion disorders: Effect on moment arms of thigh muscles

BACKGROUND Lower limb torsion disorders have been considered as a factor inducing gonarthrosis and the three-dimensional effect of the surgical correction is not well reported yet. This paper reports an in vitro study aiming at quantifying the relationships between experimental femoral torsion disorders and moment arms of thigh muscles. METHODS Five unembalmed lower limbs were used and fixed on an experimental jig. Muscles were loaded and 6 Linear Variable Differential Transformers were used to measure tendon excursions. Experimental osteotomies were performed to simulate torsions by steps of 6° up to 18°. Moment arms of the main thigh muscles were estimated by the tendon excursion method during knee flexion. FINDINGS Moment arms of the tensor of fascia latae, the gracilis and the semitendinosus were significantly influenced by experimental conditions while the rectus femoris, the biceps femoris and the semimembranosus did not show modifications. Medial femoral torsion decreased the moment arm of both the gracilis and the semimembranosus. Opposite changes were observed during lateral femoral torsion. The moment arm of the tensor of fascia latae decreased significantly after 30° of knee flexion for 18° of medial femoral torsion. INTERPRETATION Our results showed that medial and lateral femoral torsion disorders induced alterations of the moment arms of the muscles located medially to the knee joint when applied in aligned lower limbs. These results highlight a potential clinical relevance of the effect of femoral torsion alterations on moment arms of muscles of the thigh which may be related, with knee kinematics modifications, to the development of long-term knee disease.

In vitro biomechanical study of femoral torsion disorders: effect on tibial proximal epiphyseal cancellous bone deformation

PurposeOsteoarthritis (OA) of the knee is a degenerative disease mainly found in elderly population. Valgus deformity seems to be directly related to lateralised gonarthrosis. Contradictory outcomes of surgical series are published in the literature and report satisfactory and unsatisfactory long-term results. Lower limb torsions disorders have been considered as being another factor inducing gonarthrosis. This paper presents an in vitro study aiming at quantifying the relationships between experimental femoral torsion disorders (medial and lateral) and the deformation of the cancellous bone of the proximal tibial epiphysis (CBTPE).MethodsFive left fresh-frozen lower limbs were used. Specimens were mounted on an experimental jig and muscles were loaded. Six measurement elements, including strain gages, were introduced into CBTPE to measure relative deformation. Experimental osteotomy control was performed using a specially devised system allowing various amplitudes of medial and lateral torsion. CBTPE deformations were measured during knee flexion movement.ResultsIntra-observer reproducibility of CBTPE deformations showed a mean coefficient of multiple correlation of 0.93 and a mean coefficient of variation of 9% for flexion. Intra-specimen repeatability showed a mean RMS difference ranging from 7 to 10% and a mean ICC of 0.98. CBTPE deformations were significantly influenced by femoral torsion disorder conditions and range-of-motion (ROM) for most measurement elements. No interaction between torsion condition and ROM was observed. Globally, CBTPE deformation in the lateral compartment increased during experimental lateral torsion disorder simulation and decreased during medial torsion simulation. The opposite behaviour was observed in the medial compartment. The decrease and/or increase were not always proportional to the degree of femoral torsional disorder simulated.ConclusionExperimental results from this study do not fully agree with previously published clinical observations on the femoral torsion disorder. The present quantified results do not support that medial femoral torsion disorder induces an increased lateral tibial deformation, which could be linked to gonarthrosis observed in this compartment. In summary, our results showed that medial and lateral femoral torsion disorder conditions applied in normally aligned lower limb induced a deformation increase in the medial and in the lateral compartment, respectively.