Stride-to-stride variability is altered during backward walking in anterior cruciate ligament deficient patients

Background: Recently backward walking is used by physical therapists to strengthen the hamstring muscles and thus improve the function of the knee joint of anterior cruciate ligament deficient patients. The aim of this study was to examine the stride-to-stride variability of anterior cruciate ligament deficient patients during backward walking. The variation of how a motor behavior emerges in time is best captured by tools derived from nonlinear dynamics, for which the temporal sequence in a series of values is the facet of interest. Methods: Fifteen patients with unilateral anterior cruciate ligament deficiency and eleven healthy controls walked backwards at their self-selected speed on a treadmill while three-dimensional knee kinematics were collected (100 Hz). A nonlinear measure, the largest Lyapunov Exponent was calculated from the resulted knee joint flexion–extension data of both groups to assess the stride-to-stride variability. Findings: Both knees of the deficient patients exhibited significantly lower Lyapunov Exponent values as compared to the healthy control group revealing more rigid movement pattern. The intact knee of the deficient patients showed significantly lower Lyapunov Exponent values as compared to the deficient knee. Interpretation: Anterior cruciate ligament (ACL) deficiency leads to loss of optimal variability regardless of the walking direction (forwards in previous studies or backwards here) as compared to healthy individuals. This could imply diminished functional responsiveness to the environmental demands for both knees of ACL deficient patients which could result in the knees being more susceptible to injury

Knee braces can decrease tibial rotation during pivoting that occurs in high demanding activities

Purpose The purpose of this study was to investigate whether knee braces could effectively decrease tibial rotation during high demanding activities. Methods Using an in vivo three-dimensional kinematic analysis, 21 physically active, healthy, male subjects were evaluated. Each subject performed two tasks that were used extensively in the literature because they combine increased rotational and translational loads on the knee, (1) descending from a stair and subsequent pivoting and (2) landing from a platform and subsequent pivoting under three conditions: (A) wearing a prophylactic brace (braced), (B) wearing a patellofemoral brace (sleeved), and (C) unbraced condition. Results In the first task, tibial rotation during the pivoting phase was significantly decreased in the braced condition as compared to the sleeved condition (P = 0.019) and the non-braced condition (P = 0.002). In the second task, the same variable was significantly decreased in the braced condition as compared to the sleeved (P = 0.001) and the unbraced condition (P \u3c 0.001). The sleeved condition also produced significantly decreased tibial rotation with respect to the unbraced condition (P = 0.021). Conclusions Bracing decreased tibial rotation in activities where increased translational and rotational forces were applied. Because knee braces decreased tibial rotation, they can possibly be used with ACL-reconstructed and ACL-deficient patients to prevent such problems. Level of evidence Case–control study, Level III

COMPARISON OF PHYSIOLOGICAL RESPONSES BETWEEN INTERVAL METHOD, 8V8 AND 4V4 GAMES AND TECHNICAL-TACTICAL EXERCISE IN SOCCER TRAINING

Purpose: Football is a sport that requires strong player demands. During the workout of improving the endurance are used exercises with or without the ball as well as racing games. In the present study we analyzed the burden of 4 different types of exercise(intermittent without the ball, 8v8 game, 4v4 game, and technical exercises) to determine which kind is best suited for improving the specific endurance. Material: The sample was 5 professional players (mean ± SD) of age (26± 2.9 years), height (1.79 ± 0,03m) and body weight (75± 3 kg). Prior to the experiment, a Test to determine the anaerobic threshold was performed. Measurements of lactic acid were made by using the Dr Lange photometer, while heart rate measurements by using POLARFT60 portable heart ratemeters. Results: The assumption of normal distribution was verified using the Kolmogorov-Smirnov test and it was found that in all variables the data follows the normal distribution. For the statistical treatment of the data a Analysis of Variance for repeated measure was used and for the detection of statistically significant differences between the measurement conditions was used the LSD multiple comparison test. The level of significance was defined as p4mmol lactic acid (F(3,12)= 21,331 p<0,05). c) in the min of the heart rate at 3-4 mmol lactic acid (F(3,12)= 3,584, p<0,05) d) in the min of heart rate at 2-3mmol lactic acid (f(3,12= 4,310,p <0,05) and e) averages of the heart rate relative to ANK (F (3,12)= 25,404, p<0,05). Conclusion: It seems that the 4 different types of exercise cause different metabolic processes of lactic acid production as well as different heart rate responses. The intermittent and 4v4 game schedule is better suited to improving the endurance the 8v8 game is suitable for improving aerobic endurance, while technical-tactical exercises do not produce sufficient stimuli to improve endurance but involve speed stimuli

Double fractures of the femur: a review of 16 patients

Background Double ipsilateral femoral fractures account for 1\u20139% of femoral fractures. There is no clear advantage between single or double implant osteosynthesis. We present a series of patients with double ipsilateral femoral fractures, to address the challenges in treatment, namely the implants for osteosynthesis and complications of treatment. Materials and methods We retrospectively studied 16 patients (7 men, 9 women; mean age, 51 years) treated from January 2015 to December 2018. Motor vehicle accidents were the leading cause of injury. Types of fractures were pertrochanteric and shaft (6), pertrochanteric and distal (2), double shaft (3), neck and shaft (2), neck and distal (1), shaft and distal (1), and triple fracture including a pertrochanteric, shaft and distal (1). In five patients, two different implants were used (plate and screws, cannulated hip screws, femoral nail), whereas in 11 patients a long femoral nail was used. Results Fourteen patients experienced union at a mean of 3 months (2\u20136 months). Two patients experienced nonunion: both had plate and screws osteosynthesis. One patient died 15 days after admission from polytrauma and another patient experienced central venous catheter thrombosis and pneumonia. Surgical complications (2 patients) included a thigh skin necrosis, and external fixator pin tract infection/infected non-union. Weight-bearing was delayed in all patients; full weight-bearing was allowed in 11 patients at 4 months postoperatively, and in four patients at 5 months. Conclusion Due to the rarity and the difficulty of standardization of double ipsilateral femoral fractures, there is variable information on the optimal osteosynthesis of the fractures and the outcome of the patients. It seems that closed reduction and long hip nailing is the treatment of choice, with few complications