Beside pathophysiological factors, pain is believed to play a crucial role in the progression of patellofemoral pain (PFP). However, the isolated effect of pain on biomechanics and quadriceps function has not been investigated in PFP. Thus, this study aimed to investigate the effect of pain on quadriceps function and lower limb biomechanics in individuals with PFP. Methods Twenty-one individuals with PFP (11 males and 10 females, age: 29.76 ±6.36 years, height: 1.74 ± 0.09m, mass: 70.12 ±8.56kg) were measured at two different occasions: when not and when experiencing acute pain. Peak quadriceps torque (concentric, eccentric and isometric) and arthrogenic muscle inhibition (AMI) was assessed. Three-dimensional motion analysis and surface electromyography of the quadriceps and hamstrings muscles were collected during running, a single-leg-squat and step-down task. The normality was assessed using the Shapiro-Wilk test and a MANOVA was performed at the 95% confidence interval. Results AMI increased significantly in acute pain. The net muscle activation of the knee extensors and flexors decreased during running in acute pain. The lower limb biomechanics and the quadriceps torque did not change in acute pain. Discussion: It appears that even if individuals with PFP experience pain they can still deliver maximal quadriceps contractions and maintain their moving patterns without biomechanical changes. However, the overall reduced activation of the quadriceps and the increased AMI indicate the presence of quadriceps inhibition in acute pain.

Previous research has reported a prevalence of running related injuries in 25.9% to 72% of all runners. A greater hip internal rotation and adduction during the stance phase in running has been associated with many running related injuries, such as patellofemoral pain. Researchers in the USA designed a treatment device 'the Powers™ strap' to facilitate an external rotation of the femur and to thereby control abnormal hip and knee motion during leisure and sport activities. However, to date no literature exists to demonstrate whether the Powers™ strap is able to reduce hip internal rotation during running. 22 healthy participants, 11 males and 11 females (age: 27.45±4.43 years, height: 1.73±0.06m, mass: 66.77±9.24kg) were asked to run on a 22m track under two conditions: without and with the Powers™ strap. Three-dimensional motion analysis was conducted using ten Qualisys OQUS 7 cameras (Qualisys AB, Sweden) and force data was captured with three AMTI force plates (BP600900, Advanced Mechanical Technology, Inc.USA). Paired sample t-tests were performed at the 95% confidence interval on all lower limb kinematic and kinetic data. The Powers™ strap significantly reduced hip and knee internal rotation throughout the stance phase of running. These results showed that the Powers™ strap has the potential to influence hip motion during running related activities, in doing so this might be beneficial for patients with lower limb injuries. Future research should investigate the influence of the Powers™ strap in subjects who suffer from running related injuries, such as patellofemoral pain.

Background: Abnormal biomechanics, especially hip internal rotation and adduction are known to be associated with patellofemoral pain (PFP). The Powers TM strap was designed to decrease hip internal rotation and to thereby stabilise the patellofemoral joint. Objectives: This study aimed to investigate whether the Powers TM strap influenced pain and lower limb biomechanics during running and squatting in individuals with PFP. Methods: 24 individuals with PFP were recruited using advertisements that were placed at fitness centres. They were asked to perform a single leg squat task (SLS) and to run on an indoor track at their own selected speed during two conditions: with and without the Powers TM strap. Immediate pain was assessed with the numeric pain rating scale. Three-dimensional motion and ground reaction force data were collected with 10 Qualisys cameras and 3 AMTI force plates. Results: Immediate pain was significantly reduced with the Powers TM strap (without the Powers TM strap: 4.04±1.91; with the Powers TM strap: 1.93±2.13). The Powers TM strap condition significantly increased hip external rotation by 4.7° during the stance phase in running and by 2.5° during the single leg squat task. Furthermore, the external knee adduction moment during the SLS and running increased significantly. Conclusion: This study assessed the effect of the Powers™ strap on lower limbs kinematics and kinetics in individual with PFP. The results suggest that the Powers TM strap has the potential to improve abnormal hip motion. Furthermore, the Powers TM strap demonstrated an ability to significantly reduce pain during functional tasks in patients with PFP.

No abstract

Ectopic teeth in the maxilla in eight patients were localised by roentgenstereo-photogrammetry and the findings confirmed at operation. This new method is likely to be useful in dental surgery.

No abstract

Patellofemoral pain (PFP) is the most frequently diagnosed condition in patients with knee complaints. It is a common overuse injury which affects young physically active individuals. Studies revealed that one third of individuals with PFP suffer from persistent complaints, indicating that current treatments fail to prevent the chronicity of symptoms. Contributing muscular factors to PFP, such as weakness, delayed onset of the vasti muscles or flexibility deficits have attained widespread acceptance. However, the failing long-term outcomes reflect the need to provide an update on the evidence of underlying muscular dysfunctional factors in PFP. A review was conducted from research databases: Pubmed, Cochrane, CINAHL, SPORTDiscus, and Web of Science. In total 63 studies with a sample size of 1419 individuals with PFP and 1657 healthy controls, were included. The majority of studies analysed muscle strength by quantifying maximal voluntary contraction (MVC) or investigated muscular activity, by using surface EMG. Muscular dysfunctional factors, such as atrophy, muscular inhibition, fatigue, and flexibility remained understudied and not sufficiently addressed in patients with PFP. Particularly muscular inhibition (MI) is an important underlying mechanism of weakness and EMG alterations, as weakness might not only be caused by a reduced voluntary contraction but also by MI. MI is induced by an inhibitory signal, which is sent by the central nervous system to the muscle resulting in an involuntary inability to recruit all necessary motor units. The treatment approach of an inhibited or weak muscle are entirely different and studies revealed that MI needs to be eliminated before improvements in muscle strength can be achieved. Although MI, fatigue, flexibility and atrophy seem to be important underlying factors in patients with PFP, they remain understudied and require future research in this area.

No abstract