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Abstract Background Manipulation under anesthesia (MUA) has been recommended for refractory arthrofibrosis after anterior cruciate ligament (ACL) reconstruction. However, the effectiveness of MUA to restore normal kinematics of the arthrofibrotic knee is still unclear. The objective of this study was to evaluate tibiofemoral and patellofemoral kinematics in six degrees-of-freedom (6DOF) in patients with arthrofibrosis before and after MUA. Methods Computed tomography and dual fluoroscopic imaging system were used to assess in vivo knee kinematics. Ten patients (6 women and 4 men; 32.6 ± 6.5y, 168.4 ± 7.8 cm, 61.8 ± 13.2 kg) were included in this study. The tibiofemoral and patellofemoral kinematics in 6DOF were collected before and one year after MUA. A simple analysis of variance was used to evaluate kinematic data of preoperative arthrofibrotic knee, postoperative arthrofibrotic knee, and the contralateral knee. Results The patella in the postoperative arthrofibrotic knee shifted significantly more inferiorly compared to the preoperative knee at 45° (P = 0.010), 60° (P = 0.008), and 75° (P = 0.049) of flexion. The patellar flexion in the postoperative arthrofibrotic knee significantly increased at 45° (P = 0.048), 60° (P = 0.037), and 75° (P = 0.006) of flexion compared to the preoperative arthrofibrotic knee. The patellar tilt was significantly decreased at 60° (P = 0.006) and at 75° (P = 0.037) of knee flexion in the postoperative arthrofibrotic knee compared to the contralateral knee. MUA significantly increased tibial internal rotation angle in the arthrofibrotic knee at 45° (P = 0.047), at 60° (P = 0.033), and at 75° (P = 0.021) of knee flexion. Conclusions MUA could restore normal patellar inferior shift, flexion, and tibial rotation compared to the contralateral side. However, the MUA could not restore normal patellar tilt of the arthrofibrotic knee. This indicated that improvement of patellar tilt should be emphasized in postoperative rehabilitation.

Background: Manipulation under anesthesia (MUA) has been recommended for refractory arthrofibrosis after anterior cruciate ligament (ACL) reconstruction. However, the effectiveness of MUA to restore normal kinematics of the arthrofibrotic knee is still unclear. The objective of this study was to evaluate tibiofemoral and patellofemoral kinematics in six degrees-of-freedom (6DOF) in patients with arthrofibrosis before and after MUA. Methods: Computed tomography and dual fluoroscopic imaging system were used to assess in vivo knee kinematics. Ten patients (6 women and 4 men; 32.6 ± 6.5y, 168.4 ± 7.8 cm, 61.8 ± 13.2 kg) were included in this study. The tibiofemoral and patellofemoral kinematics in 6DOF were collected before and one year after MUA. A simple analysis of variance was used to evaluate kinematic data of preoperative arthrofibrotic knee, postoperative arthrofibrotic knee, and the contralateral knee. Results: The patella in the postoperative arthrofibrotic knee shifted significantly more inferiorly compared to the preoperative knee at 45° (P = 0.010), 60° (P = 0.008), and 75° (P = 0.049) of flexion. The patellar flexion in the postoperative arthrofibrotic knee significantly increased at 45° (P = 0.048), 60° (P = 0.037), and 75° (P = 0.006) of flexion compared to the preoperative arthrofibrotic knee. The patellar tilt was significantly decreased at 60° (P = 0.006) and at 75° (P = 0.037) of knee flexion in the postoperative arthrofibrotic knee compared to the contralateral knee. MUA significantly increased tibial internal rotation angle in the arthrofibrotic knee at 45° (P = 0.047), at 60° (P = 0.033), and at 75° (P = 0.021) of knee flexion. Conclusions: MUA could restore normal patellar inferior shift, flexion, and tibial rotation compared to the contralateral side. However, the MUA could not restore normal patellar tilt of the arthrofibrotic knee. This indicated that improvement of patellar tilt should be emphasized in postoperative rehabilitation. Highlights: The abnormal knee kinematics has been thought to be an important factor contributing to the associated joint degeneration in patients with arthrofibrosis after ACL reconstruction. Despite the effectiveness of MUA in the ROM gains for patients with knee arthrofibrosis, the effectiveness of MUA to restore normal knee kinematics in patients with arthrofibrosis after ACL reconstruction is still unclear. The MUA could restore normal patellar inferior shift, flexion, and tibial rotation. The MUA could not restore normal patellar tilt of the arthrofibrotic knee, indicating that improvement of patellar tilt should be emphasized in postoperative rehabilitation. [ABSTRACT FROM AUTHOR]

Abstract Background This study was aimed to develop a novel dynamic measurement technique for testing the material properties and investigating the effect of continuous compression load on the structural and mechanical properties of human heel pad during actual gait. Methods The dual fluoroscopic imaging system (DFIS) and dynamic foot-ground contact pressure-test plate were used for measuring the material properties, including primary thickness, peak strain, peak stress, elastic modulus, viscous modulus and energy dissipation rate (EDR), both at time zero and following continuous loading. Ten healthy pilot subjects, aged from 23 to 72 (average: 46.5 ± 17.6), were enrolled. A “three-step gait cycle” is performed for all subjects, with the second step striking at a marked position on the force plate with the heel to maintain the location of the tested foot to be in the view of fluoroscopes. The subjects were measured at both relaxed (time-zero group) and fatigue (continuous-loading group) statuses, and the left and right heels were measured using the identical procedures. Results The peak strain, peak stress, elastic modulus, and EDR are similar before and after continuous load, while the viscous modulus was significantly decreased (median: 43.9 vs. 20.37 kPa•s; p

ObjectiveThis study was aimed to compare the material properties of heel pad between diabetes patients and healthy adults, and investigate the impact of compressive loading history and length of diabetes course on the material properties of heel pad.MethodsThe dual fluoroscopic imaging system (DFIS) and dynamic foot-ground contact pressure-test plate were used for measuring the material properties, including primary thickness, peak strain, peak stress, stiffness, viscous modulus and energy dissipation ratio (EDR), both at time zero and following continuous loading. Material properties between healthy adults and DM patients were compared both at time zero and following continuous weight bearing. After then, comparison between time-zero material properties and properties following continuous loading was performed to identify the loading history-dependent biomechanical behaviour of heel pad. Subgroup-based sensitivity analysis was then conducted to investigate the diabetes course (

Background: This study was aimed to develop a novel dynamic measurement technique for testing the material properties and investigating the effect of continuous compression load on the structural and mechanical properties of human heel pad during actual gait.Methods: The dual fluoroscopic imaging system (DFIS) and dynamic foot-ground contact pressure-test plate were used for measuring the material properties, including primary thickness, peak strain, peak stress, elastic modulus, viscous modulus and energy dissipation rate (EDR), both at time zero and following continuous loading. Ten healthy pilot subjects, aged from 23 to 72 (average: 46.5 ± 17.6), were enrolled. A "three-step gait cycle" is performed for all subjects, with the second step striking at a marked position on the force plate with the heel to maintain the location of the tested foot to be in the view of fluoroscopes. The subjects were measured at both relaxed (time-zero group) and fatigue (continuous-loading group) statuses, and the left and right heels were measured using the identical procedures.Results: The peak strain, peak stress, elastic modulus, and EDR are similar before and after continuous load, while the viscous modulus was significantly decreased (median: 43.9 vs. 20.37 kPa•s; p < 0.001) as well as primary thicknesses (median: 15.99 vs. 15.72 mm; p < 0.001). Age is demonstrated to be moderately correlated with the primary thicknesses both at time zero (R = -0.507) and following continuous load (R = -0.607). The peak stress was significantly correlated with the elastic modulus before (R = 0.741) and after continuous load (R = 0.802). The peak strain was correlated with the elastic modulus before (R = -0.765) and after continuous load (R = -0.801). The correlations between the viscous modulus and peak stress/ peak strain are similar to above(R = 0.643, 0.577, - 0.586 and - 0.717 respectively). The viscous modulus is positively correlated with the elastic modulus before (R = 0.821) and after continuous load (R = 0.784).Conclusions: By using dynamic fluoroscopy combined with the plantar pressure plate, the in vivo viscoelastic properties and other data of the heel pad in the actual gait can be obtained. Age was negatively correlated with the primary thickness of heel pad and peak strain, and was positively correlated with viscous modulus. Repetitive loading could decrease the primary thickness of heel pad and viscous modulus. [ABSTRACT FROM AUTHOR]