Kostas Patras

Follow-up evaluation 2 years after ACL reconstruction with bone-patellar tendon-bone graft shows that excessive tibial rotation persists.

ObjectiveTo investigate in vivo if the increased tibial rotation found in anterior cruciate ligament (ACL)-deficient patients before surgery is restored 2 years after the reconstruction, during 2 high-demanding activities. DesignProspective follow-up study. SettingA gait analysis laboratory. ParticipantsNine subjects with unilateral ACL rupture, reconstructed with a bone–patellar tendon–bone (BPTB) graft, and 10 healthy control subjects. InterventionsAll the ACL-deficient patients underwent a unilateral ACL reconstruction after prereconstruction data acquisition. Main Outcome MeasurementsUsing a 6-camera motion analysis system, kinematics were collected as subjects (1) descended from a stair and, after foot contact, pivoted on the landing leg at 90°; and (2) jumped from a platform, landed with both feet on the ground and, after foot contact, pivoted on the right or left leg at 90° in a similar fashion. The dependent variable examined was the maximum range of motion of tibial rotation during the pivoting period. ResultsFor both activities, no significant differences were found between the control healthy knee and the intact knee of the patient group before and 2 years after the ACL reconstruction. Significant differences were found between the control healthy knee and the affected knee of the patients group for both activities, both before and 2 years after the ACL reconstruction. ConclusionThe increased tibial rotation found in the ACL-deficient knees was not restored with reconstruction using a BPTB graft, even 2 years postoperatively. The authors propose that this excessive tibial rotation over time may lead to further deterioration of the knee resulting from abnormal loading at areas of the cartilage that are not commonly loaded in a healthy knee.

Velocity at Lactate Threshold and Running Economy Must Also be Considered Along With Maximal Oxygen Uptake When Testing Elite Soccer Players During Preseason

Ziogas, GG, Patras, KN, Stergiou, N, and Georgoulis, AD. Velocity at lactate threshold and running economy must also be considered along with maximal oxygen uptake when testing elite soccer players during preseason. J Strength Cond Res 25(2): 414-419, 2011-Maximal oxygen uptake (&OV0312;o2max) has been traditionally used to explain physiologic differences among soccer teams of different ranking. However, other endurance markers may have greater discriminatory ability. The purpose of this study was to examine whether velocity at lactate threshold and running economy can be used to better discriminate endurance characteristics of soccer teams of different levels along with &OV0312;o2max during preseason testing. One hundred twenty-nine professional Greek soccer players participating in the top 3 divisions underwent an incremental treadmill test to exhaustion using expired gas analysis and simultaneous blood lactate measurements. Velocity at lactate threshold was determined using the Dmax method, and running economy was measured at 12 km·h−1. Analyses of variation were used to compare for differences between divisions. Velocity at lactate threshold was the only variable that was statistically different between any 2 divisions. In every comparison, the higher division had the higher velocity at lactate threshold. The &OV0312;o2max was statistically different only between the top 2 divisions. Running economy was statistically different between divisions with similar &OV0312;o2max, with better running economy for the higher division in each comparison. These results indicate that velocity at lactate threshold can be used to better discriminate endurance characteristics of soccer teams of different level along with &OV0312;o2max during preseason testing. Running economy may reveal differences between teams with similar &OV0312;o2max.

The Effect of Anterior Cruciate Ligament Reconstruction on Stride-to-Stride Variability

PURPOSE The purpose of our study was to investigate the functional outcome after anterior cruciate ligament (ACL) reconstruction using bone-patellar tendon-bone (BPTB) and quadrupled semitendinosus and gracilis tendon (ST/G) autografts by evaluating stride-to-stride variability. METHODS Six patients with BPTB and 6 patients with STG ACL reconstruction, 2 years postoperatively, and 6 healthy control subjects walked on a treadmill at a self-selected pace while 2 minutes of continuous kinematic data were recorded with a 6-camera optoelectronic system. Stride-to-stride variability was calculated from the knee flexion/extension data using the nonlinear measure of approximate entropy, which estimates the regularity of movement patterns over time. RESULTS ACL reconstruction affects stride-to-stride variability. Both the BPTB and the ST/G groups had significantly larger approximate entropy values than the healthy controls. No differences were found between the BPTB and the ST/G approximate entropy values. CONCLUSIONS After ACL reconstruction using either BPTB or quadrupled ST/G, there is increased gait variability as compared to healthy individuals. This could be caused by the altered neuromuscular activity found in ACL-reconstructed limbs. LEVEL OF EVIDENCE Level III, case control study.

ACL reconstructed patients with a BPTB graft present an impaired vastus lateralis neuromuscular response during high intensity running

The purpose of the present study was to investigate whether the electromyographic response of the vastus lateralis (VL) muscle in the anterior cruciate ligament (ACL) reconstructed leg is similar to that of the intact contralateral leg and healthy controls, during moderate and high intensity running. Fourteen bone-patellar tendon-bone (BPTB) ACL reconstructed amateur soccer players and fourteen healthy control amateur soccer players volunteered to participate in the study. Electromyographic (EMG) traces from the vastus lateralis (VL) muscle were collected bilaterally, as athletes ran on a treadmill for 10 min on separate occasions, at moderate and high intensity. The dependent variable examined was the EMG amplitude during stance. During the moderate intensity running, EMG amplitude of the VL did not increase with time for any of the tested legs. During the high intensity running, the EMG amplitude of the VL increased significantly with time for the intact (F=6.747, p=0.001) and the control leg (F=4.258, p=0.008), but remained unchanged for the ACL reconstructed leg. During moderate intensity running, there was no difference in the neuromuscular response of the VL in the reconstructed leg compared to the intact and control leg. High intensity running resulted in an impaired neuromuscular response of the VL in the reconstructed leg compared to the intact and control leg. It seems that potential impairments of the neuromuscular response after ACL reconstruction should be tested under high rather than moderate intensity efforts.