Submitted by MARCELLA FERRAZ PAZZINATTO null (ferraz_mar@hotmail.com) on 2016-05-13T17:13:57Z No. of bitstreams: 1 Dissertacao_final.pdf: 1372783 bytes, checksum: 82c520a2d6f64d7158d4001c043c712b (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-05-16T16:48:45Z (GMT) No. of bitstreams: 1 pazzinatto_mf_me_prud.pdf: 1372783 bytes, checksum: 82c520a2d6f64d7158d4001c043c712b (MD5) / Made available in DSpace on 2016-05-16T16:48:45Z (GMT). No. of bitstreams: 1 pazzinatto_mf_me_prud.pdf: 1372783 bytes, checksum: 82c520a2d6f64d7158d4001c043c712b (MD5) Previous issue date: 2016-04-29 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A dor femoropatelar (DFP) é considerada um “enigma ortopédico”, e uma das desordens musculoesqueléticas mais desafiadoras para se gerenciar. Isso porque até o presente momento não se tem definição acerca da(s) causa(s) que podem levar a esta desordem. Há mais de duas décadas têm-se investigado a presença de alterações biomecânicas em indivíduos com DFP durante as mais diversas atividades, como corrida, subida e descida de escada, agachamento e salto. Os parâmetros eletromiográficos (EMG) relacionados ao tempo e amplitude de ativação dos músculos vasto lateral (VL) e vasto medial (VM) são frequentemente abordados em estudos com essa população, no entanto, os resultados são controversos e acredita-se que uma das possíveis causas para essa inconsistência seja a característica intermitente dos sintomas. Ou seja, em determinados momentos a dor está presente e em outros não, independente da atividade que esteja sendo desenvolvida. Sabe-se que a dor recorrente pode levar a alterações no mecanismo central de controle da dor gerando respostas exageradas frente a estímulos dolorosos (hiperalgesia). Acredita-se que mulheres com DFP apresentam hiperalgesia tanto local quanto generalizada, no entanto, não se sabe o quanto a presença da dor no momento da avaliação pode alterar esses mecanismos de hiperalgesia. Diante disso, os objetivos gerais desta dissertação foram analisar o quanto a presença da dor afeta a hiperalgesia e os parâmetros EMG em mulheres com DFP, além de determinar pontos de corte para identificar a presença de hiperalgesia em mulheres com DFP. Os parâmetros EMG foram avaliados durante o gesto de subida de escada, e assim como os limiares pressóricos de dor (LPD) e a escala visual analógica (EVA) de dor, foram coletados em dois momentos antes e após um protocolo de esforço da articulação femoropatelar. Este protocolo foi realizado com o intuito de exacerbar os sintomas específicos da DFP e consistiu em 15 subidas de escada com 35% do peso corporal alocado em uma mochila e com ritmo demarcado por um metrônomo (96 degraus/min). Observou-se que mulheres com DFP apresentam LPDs reduzidos em comparação com mulheres assintomáticas e após o protocolo de esforço os LPDs avaliados ao redor do joelho, no grupo com DFP, reduziram significativamente comparado a avaliação prévia, no entanto, não houve diferença no LPD do ponto distante. Os pontos de corte encontrados apresentaram bons valores de acurácia diagnóstica, podendo ser úteis para a prática clínica na discriminação de indivíduos com e sem hiperalgesia. Já quanto aos parâmetros EMG avaliados em mulheres com DFP antes e após o protocolo de esforço, não houve diferença entre o início da ativação dos músculos VM e VL na presença da dor, mas houve aumento na amplitude do sinal EMG do VL e, consequentemente, redução na razão de ativação VM/VL após o protocolo de esforço. De acordo com estes resultados observa-se que a presença da dor é capaz de alterar os mecanismos centrais de modulação da dor, aumentando a hiperalgesia no local da desordem. A confirmação da presença de hiperalgesia local e generalizada em mulheres com DFP é de fundamental importância para traçar estratégias de tratamento, e a definição de pontos de corte capazes de discriminar os indivíduos quanto a presença de hiperalgesia facilita o gerenciamento desta desordem. E curiosamente os tratamentos visando o equilíbrio na ativação dos músculos VM e VL parecem não ser a melhor opção já que esse quesito não sofreu alteração diante do principal sintoma da DFP. / As there is no definition about etiological factors of patellofemoral pain (PFP), it is considered an “orthopaedic enigma” and one of musculoskeletal disorders most challenging to manage. More than two decades, researchers have investigated the presence of biomechanics alteration in individuals with PFP during different activities as run, stair deambulation, squatting and jump. The electromyographic (EMG) parameters related to timing and amplitude of activation of vastus lateralis (VL) and vastus medialis (VM) muscles are often addressed in studies with PFP. However, the results are controversial and a plausible explanation may be the intermitent characteristic of the symptoms. In other words, at certain times the pain is present and not in others, regardless of the activity that is being developed. It is knowing that recurrent pain may result in dysfunctional analgesic control generating exaggerated responses to painful stimuli (hyperalgesia). Women with FPF present local and widespread hyperalgesia, however, it is unknown how the presence of pain at the moment of evaluation may alter the hyperalgesia. Thus, the overall aims were to analyze how the presence of pain affects hyperalgesia and EMG parameters in women with PFP, moreover, to determine cutoff points to identify the presence of hyperalgesia in women with PFP. EMG parameters were evaluated during stair climbing. EMG parameters, pressure pain thresholds (PPTs) and visual analogue scale of pain (VAS) were collected in two conditions: before and after a patellofemoral joint loading protocol. This protocol aimed to arouse the specific symptoms of PFP and it was composed to 15 stair deambulation with 35% of body mass allocated in a backpack and the rhythm was demarcated by a metronome (96 steps/min). The women presented lower PPTs compared to pain free group. After the protocol, the PPTs around the knee decreased, whereas the PPT at a remote site to the knee not changed in women with PFP. The PPT cutoff points presented good capability to discriminate women with and without PFP. There was no difference in VL and VM onset of activation in presence of pain, however, the VL amplitude increased and VM/VL activation ratio decreased after the patellofemoral joint loading protocol. According to these results, the presence of pain changed the central mechanisms of pain modulation, increasing hyperalgesia at the site of the disorder. The cutoff points can guide clinicians towards identifying the presence of local and widespread hyperalgesia in women with PFP. Thus, clinicians may be able to identify which patients would benefit from non-mechanical interventions focusing on components aimed at pain neuroscience education. Interestingly, the treatments aiming to reduce the imbalance between VM and VL muscles do not seem to be the best option insofar as this parameter did not change in the presence of the main symptom of PFP. / FAPESP: 2014/10839-0

Background: Knee pain is a common musculoskeletal complaint with an estimated annual population prevalence of 25% in people aged over 55 years. There are many causes of knee pain though osteoarthritis (OA) is one of the most frequent. Not all people with OA, however, have knee pain. There is discordance between pain intensity and disease severity, the reason for which is unknown. Variation in pain sensitivity may be one possible explanation. Quantitative sensory testing (QST) is a non-invasive technique using non-painful and painful stimuli to assess altered sensitivities in the skin and muscle. Little is known, however, about pain sensitivity in people with knee pain and the role of psychosocial factors in relation to pain sensitivity and pain intensity. Intra-articular steroids are a widely used and effective therapy for knee OA though response to treatment varies in both magnitude and duration of response. Pain sensitivity and/or psychosocial factors may explain some of the variation observed in response to treatment. Aims: To determine whether (i) greater sensitivity to stimuli is associated with higher levels of pain intensity in a population-based sample with knee pain, and whether those associations are mediated by psychosocial factors, (ii) there are changes in QST following intra-articular steroid injections in patients with symptomatic knee OA, and (iii) whether psychosocial factors and sensitivity to stimuli at baseline predict change in pain following intervention. Methods: 72 men and women with knee pain were recruited from a population-based cohort. All had QST assessments and completed a range of questionnaire instruments addressing pain intensity and psychosocial factors. QST assessments (including thermal, mechanical, vibration and pressure) were made at the most affected knee and contralateral forearm. Assessments of tender point count, wind-up ratio and diffuse noxious inhibitory control were also performed. Structural equation modelling was used to determine whether associations between QST measures and pain intensity were mediated by a latent psychosocial factor. In a separate open label trial of intra-articular steroid injections, 32 men and women with symptomatic knee OA underwent QST assessments and also completed questionnaires. The assessments were performed at both knees at the baseline visit (prior to injection) and at a post-injection visit 5-15 days later. Changes in QST were assessed using Wilcoxon matched pairs signed-rank with linear regression used to determine baseline QST predictors of change in pain. Results: In the observational study, mechanical hyperalgesia (tender point count, mechanical pain sensitivity, and allodynia), illness perceptions, catastrophizing and disability scores were positively associated with higher levels of pain intensity. Mediation analyses revealed stronger associations for the indirect effect including a latent psychosocial mediator between measures of mechanical hyperalgesia and global pain, and stronger associations for the direct effect between measures of mechanical hyperalgesia and knee pain. In the intervention study no changes in QST were observed between visits. However, lower baseline mechanical pain thresholds at the injected knee and illness perceptions predicted response to treatment. Conclusion: Illness perceptions and mechanical hyperalgesia can be used to identify subjects experiencing higher levels of global and knee pain intensity, and those who were more likely to respond to intra-articular steroid therapy. Changes in knee pain following intervention with steroid injection are not explained by changes in pain sensitivity.

OBJECTIVE: Patellofemoral Pain Syndrome (PFPS) is the most common diagnosis in patients presenting knee pain (~25%), and one of the most common diagnosis in sports medicine centers. Here we examine believed risk factors in Patellofemoral Pain Syndrome (PFPS) and assess their relationship to PFPS. METHODS: The study was a retrospective study completed at Johns Hopkins Department of Orthopaedic Surgery. All patients, who were referred to physical therapy at Johns Hopkins Rehabilitation Therapy Services Clinic, were diagnosed with PFPS for the first time and were mostly recreational runners. Body mass indexes (BMI) were calculated from weight and height. Pain scores were taken using the visual analog scale. Strength measurements were taken from the left and right leg for the following measurements: hip abduction external rotation, hip abduction, knee extension, and hip extension. Balance measurements were also taken on the left and right sides measuring the postural sway with eyes open and eyes closed. Statistical analysis were accomplished using excel. RESULTS: A total of 23 patients were included in the present study, 9 females and 14 males. BMI's (lb/in^2) for the population was 25.1 (±4.2), males were 26.4 (±3.6) and females were 23.2 (±4.2). Pain scores were 6 (±1.9) out of 10 for the total population, males, and females. The total population had composite hip scores 35.0% and 22.9% for the right and left sides, while the knee extension was 50.7% and 51.7%. All hip scores were below 40 except for right hip ABD/ER in females and lower than knee extension scores in males, females, and total population. The ratio for right eyes closed to open was 34.2 (±62.7) and left eye closed to open was 24.7 (±44.3) for the total population CONCLUSION: This study demonstrated that age and BMI may have an effect on the development of PFPS but no statistical significance was confirmed. Results suggest that hip strength is a better indicator than knee strength in risk associated with PFPS. Balance appears to be more of an indicator of poor hip strength than as a measurement or potential risk factor for PFPS.

Chronic pain is common in the United States, with studies suggesting that pain impacts 20% of adults annually. There are many pharmacological agents used to treat pain, including but not limited to opioids, gabapentin, oral analgesics, and antidepressants as analgesics. Acupuncture has been shown to be effective in reducing musculoskeletal pain, headaches, and chemotherapy-induced nausea and vomiting in adults. Children also suffer from chronic pain, but minimal research has examined the use of acupuncture for treatment of pediatric pain. The purpose of this retrospective chart review is to quantify pain reduction in pediatric joint pain treated with acupuncture. The pain scores prior to first and sixth acupuncture treatment for knee pain were compared for 14 pediatric patients. Daily activity and functions scores were obtained from 6 patients. Our results revealed a statistically significant reduction in median pain score (P=0.002). 47% of our sample reported clinically significant pain reduction (> 30% reduction in pain on numerical rating scale (NRS)) and 60% of individuals with baseline moderate-severe pain reported clinically significant pain reduction. The median interference of pain with daily activity was reduced in 5 of 7 daily activities. Our results suggest that acupuncture might be an effective treatment modality for pediatric knee pain and improving quality of life.

“Excessive” and/or “delayed” subtalar joint (STJ) pronation has been linked to overuse injuries because of its influence on tibial internal rotation (TIR). The transfer of STJ pronation to TIR occurs via the talocrual joint, believed to have limited transverse plane motion. However, studies have shown the talocrural joint to have more transverse plane motion than once believed, therefore it is feasible that the STJ will only influence the motion of the tibia once this motion has been exhausted. Currently, studies evaluating this relationship have focused on peak joint angles and excursion without reference to the amount of motion available at the ankle joint complex (AJC). Therefore the purpose of these studies were to evaluate whether runners with anterior knee pain (AKP) utilize a greater percentage of their available eversion motion (eversion buffer), evaluate the effects of small eversion buffers on coordination, and evaluate the influence of orthotics on those with AKP and with the smallest eversion buffers. This study found healthy and injured runners, for the most part, presented with no significant differences in traditional pronation related variables. The one exception was peak pronation velocity, where injured runners demonstrated faster velocities. On the other hand injured runners had significantly smaller eversion buffers which lead them to change their coordinative pattern earlier during stance. This difference in pattern also caused the intra-individual coupling variability to peak earlier during stance. Orthotics successfully controlled the kinematics of the AJC and increased the eversion buffer of injured runners and in those displaying the smallest buffers. While orthotics successfully influenced the kinematics of the AJC, they did not influence those of the tibia and knee. These changes at the AJC did not have a strong impact on the coordinative patterns of the lower extremity, however demonstrated a trend toward being able to influence the intra-individual coupling variability. In summary, injured runners demonstrated smaller eversion buffers and changed their coordinative pattern earlier during stance. While orthotics successfully increased the eversion buffer, they did not strongly influence coordination variables. Future studies analyzing pronation related variables in injured populations should evaluate them relative to the available motion at the AJC.

People with knee Osteoarthritis (OA) often develop negative psychosocial beliefs like pain catastrophizing and fear avoidance that can interfere with engagement in physical activity and adherence to exercise. This can lead to further pain and disability since exercise and physical activity are the first line treatment for knee OA. Therefore, there is a need for interventions that address negative psychosocial beliefs related to exercise and low adherence along with addressing physical impairments of knee OA. This dissertation examined the safety, feasibility, and acceptability of a novel telehealth mindful exercise intervention for people with knee OA. The mindful exercise intervention trains individuals to incorporate concepts of mindfulness into strengthening exercises recommended for knee OA. The intervention was delivered via telehealth to facilitate access. Study 1 used a decentralized randomized controlled trial (RCT) of mindful exercise (n=21) vs. exercise alone (n=19) in people with knee OA. Mindful exercise was safe with 0 adverse events (vs. 4 in exercise group) and lower use of oral analgesics. The design was feasible for recruitment and retention, but adherence was suboptimal (53% in mindful exercise group) and the cohort was not racially diverse. Participants in the mindful exercise group reported larger clinically meaningful improvements in pain intensity, interference, catastrophizing, quality of life, and global assessment of knee OA compared to the exercise group. Study 2 was to qualitatively determine the acceptability of the mindful exercise intervention. Participants in the mindful exercise group of the RCT (n = 13 of 21) participated in individual interviews that were informed by the Theoretical Framework of Acceptability. Participants valued the content (exercise and mindfulness) and format (telehealth, group) of the intervention. Areas for further refinement included exercise selection and equipment, additional support and education on mindfulness, and greater flexibility with timing and nature of intervention sessions. Study 3 investigated the association between telehealth satisfaction and ehealth literacy in both groups. Participants in this cohort had high ehealth literacy (mean = 31.3 on a 8–40 scale) at baseline and high satisfaction with telehealth (mean = 5.6 on a 1–7 scale) at the end of the intervention. There was no association between ehealth literacy and telehealth satisfaction (R2=0.01, p=0.61). In conclusion, telehealth mindful exercise could be a safe and feasible intervention for people with knee OA. However, further refinement to improve adherence and acceptability are needed prior to efficacy studies.

Yes / When lying supine, due to the reaction force from the mattress acting mostly through the heel, an external knee-extension joint-torque is induced that keeps the knee fully extended. This torque becomes zero if the feet are hung over the end of the support. This study investigated, in patients with knee-osteoarthritis (knee-OA) who routinely sleep supine, whether a change to such a sleeping position would ameliorate the knee pain and associated physical problems they suffer. Patients were recruited (General-Practitioners Centre, UK) over a 9-month period; those eligible (51/70) were randomly allocated to an intervention (65% female; age 71.5 [11.3] yrs; BMI, 29.20 [5.54] kg/m2; knee-OA severity, 20 mild–mod/3 severe) or control group (63% female; age, 68.3 [9.7] yrs; BMI, 28.69 [5.51] kg/m2; knee-OA severity, 17 mild–mod/2 severe). The primary outcome was improvements (0 [worst] to 100 [best]) in knee pain at 3 months and was rated in the Knee-Injury-and-Osteoarthritis-Outcome-Score questionnaire (KOOS). Secondary outcomes were improvements (0–100) in the other four KOOS-subscales. There were no differences between groups in KOOS outcomes at baseline, and there were no changes in KOOS outcomes in the control group at 3 months. Relative to the baseline KOOS values in Knee-Pain (50.1), Symptoms (52.5), Activities-of-Daily-Living (53.8) and Quality-of-Life (31.5), were all seen to improve at 3 months in the intervention group (by between 11.9 and 12.9); however, when comparing to controls, only the improvements in the subscale Activities-of-Daily-Living (which improved by 12.2) were statistically significant. Findings indicate that for those with knee-OA who routinely sleep supine, sleeping with the feet over the end of the mattress (to prevent the knee being pushed into/held in full extension) can help ameliorate the physical problems they suffer.

Previous studies for treating Patellofemoral Pain Syndrome (PFPS) are controversial regarding the effectiveness in alleviating anterior knee pain (AKP). The muscular imbalance between the vastus medialis oblique/vastus lateralis (VMO/VL) may be the underlying mechanical issue causing PFPS. It is hypothesized that Botox can decrease the force production capability of the lateral musculature mechanically similar to surgery. Strengthening the VMO while using Botox treatment can alleviating the muscular imbalance that occurs with subjects with PFPS. A double blind study, having all participants blinded and uninformed of the injection contents, was implemented to test this hypothesis testing three female subjects. Four knees were treated. One subject received the Botox treatment and serially a placebo injection in the other limb. Two other subjects received placebo injections. EMG was executed to evaluate functional testing and the performance of the injections during extension exercises. Electromyography (EMG) data were collected from the muscle groups while the subjects performed forceful knee extension activities on an isokinetic dynamometer. In addition, kinetic jump data and self-reports of pain and activity were collected. Data were collected four times during a 12-week period. The subject who received Botox injections expressed a significant decrease in reported PFP and an increase in daily activities. Botox was safe and effective in eliminating anterior knee pain. The VMO and VL resulted in similar fatigue indices at the completion of the 12- week study. The VMO and VL both resisted fatigue during at week 12.

A dor crônica de joelho secundária a osteoartrite é uma patologia comum com a progressão da idade e que vem aumentando sua prevalência a medida que se elevam a expectativa de vida e os índices de obesidade e sobrepeso. A consequência desses sintomas se reflete de maneira direta sobre a capacidade de realização de atividades diárias, a qualidade do sono e a capacidade laboral do indivíduo. O impacto psicológico, social e econômico da dor crônica de joelho representam um desafio de saúde pública, demandando tratamento eficiente e custo-efetivo. As terapias farmacológicas com frequência apresentam benefício limitado associado a diversos efeitos colaterais. Os procedimentos invasivos não cirúrgicos, como a injeção intraarticular de ácido hialurônico, representam uma alternativa em casos refratários ao tratamento clínico, sendo utilizados como terapia complementar, entretanto apresentam benefício limitado e insuficiente para o controle da dor em casos severos. Os procedimentos cirúrgicos, como a artroplastia total do joelho, habitualmente apresentam resultados satisfatórios na doença avançada, contudo são limitadas pelo seu alto custo, risco cirúrgico inerente e pequena capacidade resolutiva diante da alta prevalência. O bloqueio dos nervos geniculados é uma técnica recentemente descrita, de fácil realização e com mínima invasão necessitando ser estudada para que possa ser aplicada no manejo clínico. Neste estudo foram selecionados pacientes com osteoartrite moderada e severa, que apresentavam dor refratária ao tratamento clínico otimizado. Foram selecionados 16 pacientes e um total de 22 joelhos foram avaliados. Inicialmente todos os pacientes foram submetidos a um pré-teste que avaliava: 1) a intensidade da dor; 2) a qualidade do sono; 3) a capacidade de realização de atividades diárias. Aleatoriamente 2 grupos foram formados, o primeiro submetido ao bloqueio intra-articular e o segundo ao bloqueio dos nervos geniculados. A solução formada por: lidocaína 1% sem vasoconstrictor - 9 mL - 90 mg adicionada de Dexametasona - 1mL - 10 mg era padrão e utilizada nos dois grupos de intervenção. Após um seguimento semanal por 12 semanas consecutivas, os paciente foram reconvocados e submetidos ao outro procedimento proposto, dessa forma todos os pacientes atuaram como o seu próprio controle (desenho de estudo \"crossover\"). Nos seguimentos semanais, assim como no pré-teste, eram avaliados a intensidade da dor, a qualidade do sono e a capacidade de realização de atividades diárias. Os resultados mostraram que o bloqueio intra-articular e o bloqueio dos nervos geniculados apresentam redução importante da dor (p < 0,01), melhora na capacidade de realização de atividades diárias (p < 0,01) e melhora na qualidade do sono (p < 0,01), no entanto não houve diferença significativa no resultado entre os grupos estudados (p > 0,05). Conclui-se que o bloqueio dos nervos geniculados surge como uma alternativa segura, minimamente invasiva e de alta eficácia, apresentando resultados semelhantes ao bloqueio intra-articular. / Chronic pain of the knee secondary to osteoarthritis is a common pathology, progressive with age and which increases its prevalence as life expectancy is raised together with obesity and overweight. A consequence of these symptoms is reflected directly on the capacity of undertaking daily activities, the quality of sleep and the work capacity of each individual. The psychological, social and economic impact of chronic knee pain represents a challenge to public health, demanding efficient treatment at a worthwhile cost. Pharmaceutical therapies frequently present a limited benefit associated with various side effects. Non-surgical invasive procedures such as an injection intra-articular of hyaluronic acid, represents an alternative in refractory cases to clinical treatment, being used as a complementary therapy, however, presenting limited and insufficient benefit for the control of pain in severe cases. Surgical procedures such as complete arthroplasty of the knee, usually presents satisfactory results in patients with an advanced osteoarthritis, but are limited by their high cost, inherent surgical risk and small resolving capability facing a high prevalence. Blocking the genicular nerves is a recently described technique, easily applied by clinical management. Patients were selected in this study with moderate and severe osteoarthritis, with refractory pain in optimized clinical treatment. 16 patients were selected and a total of 22 knees were evaluated. Initially all the patients were submitted to a pre-test which evaluated: 1) the intensity of pain; 2) the quality of sleep; 3) the capacity to undertake daily activities. Two groups were formed randomly, the first submitted to intra-articular blocking and the second to blocking the genicular nerves. A solution of lidocaine 1% without a vasoconstrictor - 9 mL - 90 mg and Dexametasona - 1 mL - 10 mg was standard and used for intervention in both groups. After a weekly appraisal for 12 consecutive weeks, the patients were recalled and submitted to another proposed procedure and in this way all the patients acted as their own control (a \"crossover\" study design). In the following weeks, as also in the pretest, the intensity of pain, the quality of sleep and the capacity of undertaking daily activities were evaluated. The results showed that the intra-articular block and the blocking of the genicular nerves presented an important reduction of pain (p<0,01) but there was no significant difference in the result between the groups studied (p>0,05). It is therefore concluded that the blocking of the genicular nerves appears as a safe alternative, minimally invasive and highly efficient, presenting results similar to the intra-articular blocking.

Study Design: Cross-sectional. Background: Although decreased hip abduction and lateral rotation strength has been found in females with patellofemoral pain syndrome (PFPS), few studies have included males. Aim: To determine if hip abduction and lateral rotation strength is decreased in males with PFPS. Methods: Eight males participated. Isometric hip abduction and external rotation strength was measured with a hand-held dynamometer. Four subjects had unilateral patellofemoral pain (mean age = 26.5 ± 7.5 years) and 4 asymptomatic subjects were controls (mean age = 23 ± 6.4 years). The recorded measurements from the symptomatic legs were compared with the asymptomatic legs, and also with the controls. Results: No significant differences in hip abduction or lateral rotation strength were found between the symptomatic and asymptomatic legs of male subjects with PFPS. The PFPS subjects did not have generally weaker hip strength compared with the asymptomatic controls. Conclusion: Males with PFPS do not appear to have decreased hip abduction and lateral rotation strength. However, the sample size was too small for conclusions to be drawn. This study can be used as a preliminary step in gathering evidence about factors affecting PFPS in males, which may in turn shed light on appropriate clinical treatments.