Análisis biomecánico de la continuación prepatelar del cuádriceps / Biomechanical assessment of the prepatellar quadriceps continuation

OBJETIVO Determinar la resistencia máxima a la tracción (RMT) de la continuación prepatelar del cuádriceps (CPC).MATERIALES Y MÉTODOS Se realizó un estudio en cadáveres humanos. Fueron incluidos diez especímenes, en los cuales se utilizaron los tercios proximal y medial de la cortical anterior de la patela para evaluar las propiedades mecánicas de la CPC. En cada espécimen, se estudió un área de sección transversal de 0,2 cm2 (A1) y 1 cm2 (A2). Se aplicó una carga gradual para determinar la RMT.RESULTADOS La mediana de la RMT en el A1 fue de 232,56 N (rango: 141,23 N a 295,33 N) y en el A2 fue de 335,30 N (rango: 216,45 N a 371,40 N). El incremento en la TMR fue significativo entre las 2 áreas (p = 0,006).CONCLUSIÓN El ignificado clínico de este estudio es que la CPC es un tejido fuerte que puede servir de anclaje seguro para reconstrucciones alrededor de la patela. Un área relativamente pequeña tolera al menos 140 N y, a medida que crece el área, también aumenta la RMT.

OBJETIVE To determine the ultimate tensile strength (UTS) of the prepatellar quadriceps continuation (PQC). MATERIALS AND METHODS A human cadaveric study was performed. Ten fresh-frozen specimens were used. The proximal and medial thirds of the anterior cortex of the patella were used to assess the mechanical properties of the PQC. In each specimen, transverse section areas measuring 0.2 cm2 (A1) and 1 cm2 (A2) were studied. A gradual load was applied to determine the UTS. RESULTS The median UTS of A1 was of 232.56 N (range: 141.23 N to 295.33 N), and that of A2 was of 335.30 N (range: 216.45 N to 371.40 N). The increment in UTS was significant between the 2 areas (p » 0.006). CONCLUSION The clinical significance of the present study lies in the fact that it shows that the PQC is a strong tissue that can be a safe anchor for reconstruction around the patella. A relatively small area supports at least 140 N, and, as the area grows, the UTS increases as well.

Effects of Fatigue on Biomechanics of Landing and Sudden Cutting Tasks / 中国运动医学杂志

Objective To determine the effect of fatigue on the risk of anterior cruciate ligament (ACL) injuries using a controlled experiment.Method Thirty-two young male adults were selected.Half of them were asked to complete landing and sudden cutting tasks when feeling fatigue,while the rest were asked to conduct the same tasks without fatigue.Results The results indicated that fatigue led to increased knee flexion and knee rotation of the support leg during the initial landing,It also resulted in significant increase in the peak knee flexion,knee internal rotation angle and knee internal rotation moment during the double support phase.Moreover,the peak value of the knee flexion angle and knee internal rotation angle increased significantly due to fatigue during the single leg support period.Conclusion Being fatigue,people might take the adaptive posture control to decrease the ground shock,which in turn decreases ACL injury risks.However,it can be neutralized by the increase in the rotational angle.

In Vivo Biomechanics Using Dual Orthogonal Fluoroscopy after Posterior Stabilized Total Knee Arthroplasty / 대한정형외과연구학회지

This study investigated the six degrees of freedom (DOF) kinematics and three-dimensional (3D) contact during kneeling after total knee replacement arthroplasty. A total of 16 South Korean female patients (22 knees) after posteriorly stabilized (PS) TKA (LPS-Flex) performed by a single surgeon were randomly recruited. The patients were imaged using a dual fluoroscopic technique while they were kneeling from initial to maximum flexion. The acquired images and 3D models were then used to recreate the in vivo pose of the components Patients flexed their knee, on average, from 107.3degrees to 128.0degrees during the kneeling activity. Changes in kinematics included proximal, medial, posterior translation and varus rotation. Articular contact moved posteriorly by 5.9 mm and 6.4 mm in the medial and lateral compartments, respectively. Contact also moved medially by 3.2 mm and 5.8 mm in the medial and lateral compartments. A decrease in articular contact was observed in both condyles, and lateral condylar lift-off increased with flexion (P=0.0001). The tibiofemoral and cam/post articular contact data acquired in this study further suggest that kneeling may be performed by patients after clinically successful PS TKA who feel comfortable with activity and are free of