M.Tech.

Background Patellofemoral pain (PFP) is a common musculoskeletal complaint with inadequate long term outcomes. We aimed to review current evidence relating to tailored interventions, address knowledge gaps concerning how tailoring should best be delivered and establish whether such interventions are feasible. This thesis investigated whether the interaction of hip and foot biomechanics better explains PFP presentation and management, and could be used to inform feasibility studies of delivering tailored interventions for individuals with this recalcitrant condition. Methods Two systematic reviews with meta-analysis identified predictors of conservative management outcomes and the effects and mechanisms of proximal rehabilitation interventions. A reliability study tested a battery of clinical measures, designed to identify biomechanical deficits common in individuals with PFP. An observational study of individuals with PFP investigated possible biomechanical mechanisms of effect for in shoe foot orthoses. A case control study design explored the electromyographic activity of the gluteal region during common rehabilitation exercises. A randomised intervention trial implemented a tailored intervention to determine feasibility. Results Outcome predictors for conservative management are currently at a derivation stage of development. A clinical battery of 14 measures showed good intra and inter rater reliability for the assessment of lower limb biomechanics. Proximal rehabilitation, combined with quadriceps, achieves favourable outcomes in the short and medium term. Gluteal muscle electromyographic activity is comparable between symptomatic and asymptomatic individuals, with specific exercises achieving desired activation patterns. Tailored intervention using biomechanical characteristics, within a randomised trial, is feasible for recruitment and retention. Conclusion Interventions directed proximal and distal to the patellofemoral joint are effective in the management of PFP. Indicators of treatment success are at a derivation stage,with findings from this thesis providing a comprehensive clinical test battery for lower limb biomechanical assessment. Feasibility of a biomechanically determined tailored intervention has been established.with findings from this thesis providing a comprehensive clinical test battery for lower limb biomechanical assessment. Feasibility of a biomechanically determined tailored intervention has been established.

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, in partial fulfillment of the requirements for the degree of Master of Science in Medicine in the field of Biokinetics Johannesburg, 2017 / Background: Patellofemoral pain (PFP) is a common knee complaint associated with pain around the patella. Research has identified altered electromyographic (EMG) activity of the knee muscles in individuals with PFP compared to a healthy population (Briani et al., 2016). Purpose: The purpose of this observational study was to identify the EMG activity of the quadriceps muscle during functional activities in participants experiencing PFP and participants with no PFP. Methods: The onset and sequence timing including the ranking and Q-angle in relation to the rectus femoris (RF), vastus medialis obliquus (VMO) and vastus lateralis (VL) activity was measured with surface EMG in 17 PFP participants and 17 controls during a sit to stand, squat, and step up and step down. Results: The RM-ANOVA discovered a significant difference in the onset of VMO compared to RF muscle between the activities in the PFP group (-0.11 to 0.07 sec; p = 0.03) and the healthy group (-0.18 to -0.03; p = <0.01), as well as the VL compared to the RF muscle in the PFP group (-0.07 to 0.13 sec; p = <0.01). Significant differences were shown comparing the ranking of EMG onset for the quadriceps muscle to each activity in the healthy group (p = <0.01 to 0.04), and in the PFP group for the sit to stand (p = 0.01). Onset of VMO activity was predominantly ranked first in the healthy group (56%) and the VL in the PFP group (44%). A Mann-Whitney U-test shown a significant relationship in the healthy group between the Q-angle and the VMO, VL and RF muscles during the step down activity (r = -0.53 to -0.55; p = 0.02 to 0.03). Conclusion: This study confirms that the quadriceps muscle responds differently to different functional activities in the PFP and healthy population respectively. The healthy group tend to utilize the VMO first, compared to the PFP group with altered onset of quadriceps activation. Furthermore, the greater the Q-angle is, the earlier the onset of quadriceps muscle will be in the healthy group. This relationship was not found in the PFP group. / MT2017

BACKGROUND and AIMS. Patellofemoral pain syndrome (PFPS) is complex and challenging musculoskeletal disorder. Maltracking of the patella is considered to be one of the primary causative factors. Vastus Medialis Oblique (VMO) and Vastus Lateralis (VL) muscle imbalance in terms of EMG magnitude and timed onset is implicated in either initiating or perpetuating the patellofemoral pain (Cowan et al, 2002, Witvrouw et al, 1996). Many physiotherapeutic treatments are aimed at addressing this muscle imbalance despite a lack of evidence confirming or refuting it exists and it's association with pain and function. The ultimate aim of the study was therefore to establish if it is appropriate to continue treating muscle imbalance in patients with clinically defined PFPS. OBJECTIVES. The overall objectives of the study were to establish: 1. If VMO-VL muscle imbalance exists in PFPS patients and if so is it specific to this condition or does a similar VMO-VL muscle imbalance exists in a healthy population? 2. If muscle imbalance does exist is it related to clinical symptoms used as indications of pain syndrome in clinical practice? 3. Is muscle imbalance associated with lower limb muscle physiology i.e. lower limb and quadriceps muscle strength in both fresh and fatigued states. METHODS. The study employed a cross-sectional design. 63 patients with patellofemoral pain syndrome (PFPS) and 63 age/sex matched healthy subjects were recruited and VMO & VL normalised EMG RMS amplitude and time onset differences were assessed during functional and experimental tasks. Additionally, correlations with pain level, functional status, muscular flexibility and biomechanical characteristics of the lower limb were explored. RESULTS. The results revealed that the VMO-VL activation patterns are task specific and most significantly related to functional stepping down task at a fast speed of execution (p=0.000). This interesting link between the type of muscle contraction, the speed of execution and the recruitment pattern of the VMO-VL was also confirmed by the non-functional isokinetic eccentric contraction (p=0.000). Additionally, it is the timing of the VMO-VL activation rather the intensity that is important. Also, a correlation appears to exist between activation pattern and duration of symptoms and knee functional performance (p=0.03) but not with the level of pain. CONCLUSION. The findings of the study suggest that the VMO-VL muscle imbalance does exist in a clinically defined PFPS population. Unlike previous studies however, this thesis suggests that specificity of the functional activities and speed of execution have a significant role to play in the muscular performance and it could be argued that this translates to a role in PFPS. It would therefore seem appropriate to continue addressing and treating this complex and challenging issue with physiotherapeutic interventions but this may need to be targeted to interventions that are tailored to addressing issues in relation to stepping down and at fast speed.

Patellofemoral pain syndrome (PFPS) is one of the most common, but least understood, knee disorders. Fulkerson (1997) believes that pathology may result from an excessive valgus force being applied to the patella. Researchers have historically examined quadriceps strength and neuromuscular activity and knee kinematics. However, results from these works have not provided conclusive answers. Powers (2003) has theorized that other structures can influence knee function, and researchers have shown that PFPS subjects can exhibit hip weakness and demonstrate altered hip kinematics during functional activities. Although they provide preliminary evidence regarding hip influences, investigations that simultaneously examine hip and knee function in PFPS subjects are needed. The primary purpose of this study was to determine functional performance, strength, neuromuscular activity (amplitudes and onset timing differences), and kinematics of the hip and knee for people diagnosed with PFPS. Eighteen females diagnosed with PFPS and 18 asymptomatic female controls participated. Subjects initially completed a 10-cm visual analog scale. Next, they completed two functional performance tests and underwent a strength assessment for the hip abductors, hip external rotators, and knee extensors. Surface electromyography (EMG) electrodes and reflective markers were donned in order to collect EMG and kinematic data during a stair-stepping task. For this purpose, subjects ascended and descended two 20-cm high steps at a standardized rate. Seven PFPS and seven control subjects were retested five to seven days later to establish measurement reliability. A repeated measures analysis of variance was used to determine group differences. Correlation coefficients were calculated to identify associations between pain and dependent measures; intraclass correlation coefficients were calculated to determine measurement reliability for both control and PFPS subjects. Results from this study showed group differences for functional performance, strength, and EMG amplitudes but none for onset timing differences or kinematics. A strong association was found between pain and hip external rotator strength and EMG amplitudes during stair-stepping. Most tests provided reliable measures with repeat testing. PFPS subjects demonstrated quadriceps dysfunction but even greater hip weakness that was correlated more with pain. Contemporary rehabilitation has focused on quadriceps strengthening; however, results from this study support the importance of the hip.

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 5 uppsatser.

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Diss. (sammanfattning) Umeå : Umeå universitet, 2005. / Härtill 4 uppsatser.

Patellofemoral pain syndrome (PFPS) is the most common injury in runners and has a significant female sex bias. Current evidence suggests that several proximal factors, including hip muscle strength, hip muscle activation, and hip kinematics during running, play a large role in the development of PFPS, particularly in females. However, the relationships between these variables are unclear. A better understanding of these relationships in both males and females could help clinicians develop targeted interventions for this syndrome. Thus, this dissertation is comprised of four studies aimed to better understand the relationships between these risk factors. The first study investigated whether there are any relationships between hip muscle strength and hip muscle activation during running. Overall, hip muscle strength and hip muscle activity during running do not appear to be strongly related. The second study used a multiple regression approach to look for predictors of hip adduction and hip internal rotation during running. Sex was a significant predictor in both models, and running speed, static subtalar inversion range of motion, and gluteus maximus amplitude were significant predictors in the hip adduction model. The third study examined the effect of decreasing hip abduction strength on running kinematics and hip muscle EMG. After the fatigue protocol, there were no changes in gluteus medius amplitude or timing, and no changes in hip kinematics during running. However, there were some changes in kinematics, particularly at the trunk, as well as differences in gluteus maximus and tensor fascia latae activation. Finally, the fourth study used an alternative biomechanical method called continuous relative phase (CRP) to investigate the effect of sex and decreasing hip abduction strength on CRP variability at the hip. Decreasing hip abduction strength increased frontal plane CRP variability from 20-40% of stance phase, primarily in females, and females demonstrated less CRP variability than males in the frontal plane and transverse planes. Overall, the results from this study improve our understanding of the relationships between hip strength, hip muscle activation, and hip kinematics during running in both males and females, which may have implications for knee injury rehabilitation strategies. This dissertation includes unpublished co-authored material.