The Arabic KOOS is a reliable and valid instrument that can be self-administered to Egyptian patients and provides a valuable basis for research and clinical projects focussing on patient-based assessments in anterior cruciate ligament (ACL), meniscus and combined injures of knee. Further studies to validate the Arabic version of the KOOS using females and elderly population with different knee problems and various educational levels in other Arabic counties are highly recommended.

Background The need to develop screening tests to find athletes who maybe predisposed to knee injuries is of prime importance in order to design individualised intervention programmes. Previous research has found 3D joint kinematics of the hip and knee during a single leg squat (SLS) to be related to those during jogging (Whatman et al., 2011). Thus, further investigation as a potential screening test is warranted. Objective To investigate the relationship between peak 3D kinematic variables during SLS with those occurring during running (RUN) and 90° cutting (CUT) tasks. Design A correlational study. Setting Undertaken in the human performance laboratory at the University of Salford. Participants 15 recreational athletes, 7 males and 8 females, (age 25.2±5.1 years; height 1.6±7.38 m; and mass 67.6 ±10.93 kg) were recruited. Interventions A ten-camera motion analysis system (Qualisys) and a force platform (AMTI) were used to collect kinematic variables during SLS, RUN, & CUT tasks. Visual 3D (C-Motion, USA) was used to process all data. Pearson correlation coefficients were used to evaluate the association between 3D variables among the three tasks. Main outcome measurements Hip and knee joint angles. Result SLS was strongly correlated to run in knee valgus and hip internal rotation (r=0.70 and 0.76, respectively), and showed moderate correlation with knee external rotation (0.42). SLS and CUT were moderate to strongly correlate to each other in knee valgus, knee flexion, and hip internal rotation (r=0.54, 0.69, and 0.54, respectively), and moderately in hip flexion (r=0.38). Discussion The findings of this study provide evidence that performance of SLS relates to performance of other tasks (running and cutting). In those individuals displaying poor motion (excessive angles) during SLS this is likely to be predictive of poor motion during running and cutting, so could negate the need for assessing individuals during these tasks.

Background: Two-dimensional (2D) analysis of knee valgus during common athletic screening tasks such as SLS has been purported to identify individuals who may be at a high-risk of ACL injury. There is limited literature exploring the relationships between joint motion during SLS and other athletic tasks associated with knee joint injuries, in order to evaluate the effectiveness of the SLS to identify athletes with hazardous knee motion in a range of athletic tasks.

Purpose: Self-reported knee instability is highly prevalent in knee osteoarthritis (OA) and affects daily physical function. An association between knee instability and muscle strength has been demonstrated in cross-sectional studies. However, no information is available on change in self-reported knee instability over time and whether change in muscle strength is associated with change in self-reported knee instability. Muscle strength itself is associated with knee joint proprioception and knee pain. Whether these factors are influencing the association between change in muscle strength and change in self-reported instability is unknown. Therefore, the aims of the study were (i) to determine the change in self-reported knee instability over two-year time, and (ii) to study the association between change in muscle strength and change in self-reported knee instability, controlled for the change in proprioception and pain over two-year time in patients with established knee OA. Methods: A total of 201 patients from the Amsterdam Osteoarthritis (AMS-OA) cohort were followed-up during two years. Self-reported knee instability, muscle strength, proprioception, pain and patient characteristics were assessed at baseline and 2 years later. Self-reported knee instability was defined as the sensation of an episode of buckling, shifting or giving way of the knee in the previous three months. Patients reporting knee instability were additionally asked for the number of episodes of instability, whether these episodes concerned the left, right or both knees, if any episodes had resulted in a fall, and the particular activity that induced an episode of instability. Muscle strength of the left and right leg was measured isokinetically (EnKnee, Enraf-Nonius, Rotterdam, Netherlands) at 60 /second. The mean muscle strength (i.e., extension and flexion) per leg was calculated to obtain a measure of overall leg muscle strength (Nm). Joint proprioception was measured as the threshold of detection of passive joint movement. Knee pain over the past week was assessed by an 11 point numeric rating scale (0e10), with higher scores representing more pain. A series of demographic variables were obtained including age, gender, height, weight, and duration of complaints. Difference between baseline and two-year values of self-reported knee instability, muscle strength, proprioception and pain was calculated with Student's t-test or when appropriate with Chi-square test. Linear regression analysis was used to determine the association between the change in knee instability and change in muscle strength. Results: Self-reported knee instability, muscle strength, proprioception and knee pain changed significantly over two-year time (p < .001, respectively). Univariate regression analysis showed that the change in muscle strength was significantly associated with change in knee joint stability, indicating that an increase in muscle strength over time resulted in an improvement in self-reported knee stability. Changes in proprioception and knee pai...

Context: A number of acute and overuse knee pathologies share a mechanism involving a poor dynamic alignment of the limb creating increased stress in the tissues. Inappropriate execution of a correct strategy during landing has been suggested to involve insufficient activity of the hip abductor and external rotator muscles. Limited data describing the relationships between hip-abductor muscle fatigue and hip/knee joint mechanics exists. Objective: To investigate the effect of fatigue of the hip abductor muscles on knee valgus angle. Design: Repeated measures. Participants: 30 asymptomatic subjects: 15 female (age 20.4 ± 1.4, range 18-26 years; height 1.66 m, range 1.60-1.76 m; weight 63.9 kg, range 58-68 kg) and 15 male subjects (age 22 ± 3.2, range 18-28 years; height 1.84 m, range 1.65-1.90 m; weight 82.1 kg, range 69-93 kg). Main Outcome Measures: Knee valgus (frontal plane projection) angle was assessed during a step landing task before and following a fatiguing protocol of the hip abductor muscles involving repeated 10 s maximal isometric contractions of the hip abductor muscles, until strength was recorded as 50 % of preintervention score. Results: Males showed no significant change in knee valgus angle at initial ground contact (p = .9 ES 0.