Patellofemoral Pain Syndrome Group Research Articles

Dynamic postural control during step down task in patients with patellofemoral pain syndrome.

[Purpose] This study aimed to examine the differences in dynamic postural control during forward step down (FSD) task in patients with patellofemoral pain syndrome (PFPS). [Participants and Methods] Sixty-eight participants (34 males and 34 females) were divided into the following 2 groups: 34 PFPS patients (17 males and 17 females) and 34 healthy controls (17 males and 17 females). Each participant performed FSD task from a height of 20 cm. A force platform was used to extract the center of pressure parameters during FSD task for calculation of time to stabilization (TTS) in the anterior-posterior (A/P) and medial-lateral (M/L) direction. [Results] PFPS group took longer time to stabilize than the healthy control group in A/P and M/L directions. A main effect for direction was found, and this indicated that the A/P TTS of 8.43 ± 0.79s was longer than the M/L TTS of 5.56 ± 1.95s in healthy participants and A/P TTS of 9.09 ± 0.82s was longer than the M/L TTS of 7.15 ± 2.11s in PFPS. [Conclusion] These findings suggest that dynamic postural control can be affected in PFPS patients.

Analysis of pain, functional capacity, muscular strength and balance in young women with Patellofemoral Pain Syndrome

Abstract Introduction: Patellofemoral Pain Syndrome (PFPS) is associated with anterior knee pain, changes in functional capacity, balance and muscle strength disorders. Objective: To quantify pain, functional capacity, strength in quadriceps (Q), gluteus medium (GM), hip external rotator (ER) muscles and balance in sedentary women with PFPS. Methods: Twenty sedentary women, aged 18 to 25 years, were divided into two groups: PFPS (N=10) and control group (N=10). All the volunteers answered the items of the Visual Analogue Scale (VAS), the Lysholm Knee Score Scale, the Anterior Knee Pain Scale (AKPS), and the Lower Extremity Functional Scale (LEFS). The participants performed the following tests: maximal voluntary isometric contraction measured by dynamometry; postural balance using the Star Excursion Balance Test (SEBT) and a force platform. Statistical analyses were performed using the Shapiro Wilk test, the Mann Whitney U test and Spearman’s correlation coefficient. Data were submitted to SPSS 20 software. Results: The PFPS group presented greater pain, balance impairment and higher average velocity of oscillation; however, no differences were observed in Q, GM and RE muscle strength and in balance analyzed by SEBT. Conclusion: Women with PFPS exhibited greater pain, worse functional capacity and body balance. Moderate correlation between both balance tests suggests the use of SEBT when the force platform is not available, which could facilitate and highlight the importance of clinical diagnosis with regard to postural balance.

Impact on Quality of Life of Patients With Different Knee Pathology and Duration of Rehabilitation

Purpose:Many knee pathologies negatively affects the quality of life of patients. The aim of this study was to determine the relationship between type of pathology, duration of rehabilitation and quality of life.Method:154 (mean age, 34.74 ± 11.8 years, 73 women) patients with meniscectomy, anterior cruciate ligament reconstruction, and patellofemoral pain syndrome treated conservatively were included in the study. The mean follow-up was 14.5 (range, 8-20) months. The patients were divided into 3 groups; meniscectomy group (Group 1; 52 patients; mean age, 37.0 ± 8.9, 27 women), anterior cruciate ligament reconstruction group (Group 2; 47 patients; mean age, 28.6 ± 8.5 years, 11 women) and patellofemoral pain syndrome group (Group 3; 50 patients; mean age, 37.7 ± 13.6, 35 women). Short Form (SF-36) was used to assess the quality of life. One-way ANOVA was used for statistical analysis with the SPSS 20 software. p <0.05 was considered significant.Results:Group 2 was found significantly younger (p=0.001). The SF-36 subscales exept physical role and mental health were different among groups (Table 1). When this difference was analysed, social, physical and mental health were found to be better in Group 2.The Comparison of Quality of Life Among 3 GroupsSF-36Group 1n=50Group 2n=54Group 3n=50pSF-36 (PCS)36,9±10,751,2±42,037,1±10,20,006SF-36 (MCS)46,7±10,348,3±10,143,9±12,40,12SF-36 (PF)60,4±27,376,2±19,556,8±23,30,001SF-36 (RP)43,8±41,645,8±43,838,6±36,90,66SF-36 (BP)41,5±21,765,3±22,542,5±20,40,001SF-36 (GH)55,1±19,674,4±19,254,48±19,60,001SF-36 (VT)55,7±20,161,7±18,849,6±16,90,005SF-36 (SF)53,1±29,467,3±25,365,7±25,30,01SF-36 (RE)75,6±37,967,7±39,755,4±41,10,03SF-36 (MH)61,3±20,170,5±17,557,8±19,80,001Conclusion:Quality of life and function of the patients appears to be significantly better in the anterior cruciate ligament group. Anterior cruciate ligament injury usually affects the younger population and they have higher motivation for treatment. In addition, we believe that patients takes longer rehabilitation program has better qality of life.

Síndrome da dor patelofemoral não altera as características baropodométricas durante a marcha em rampa e escadas

RESUMO Este estudo teve como objetivo avaliar as características baropodométricas durante a fase de apoio da marcha em escadas e rampa de sujeitos com e sem síndrome da dor patelofemoral (SDPF). Participaram 55 indivíduos do gênero feminino, 24 com SDPF (GSDPF) e 31 clinicamente saudáveis (GC), pareados em idade, estatura e massa corporal. Foram avaliadas as variáveis pico de pressão, área de contato e tempo de contato em seis regiões plantares (antepé medial, antepé lateral, médio pé, retropé medial, retropé central e retropé lateral), por meio do sistema Pedar-X, durante a realização de quatro atividades funcionais (subir e descer escadas e rampa). A ordem de realização das avaliações foi randomizada. A intensidade da dor dos sujeitos antes e após as atividades foi avaliada pela Escala Visual Numérica (EVN). Os dados foram analisados por meio da estatística descritiva e inferencial (Testes T-independente, Wilcoxon e ANOVA 2x6), com nível de significância de p≤0,05. Não foram observadas diferenças entre os grupos em relação ao pico de pressão, área de contato e tempo de contato nas seis regiões plantares analisadas durante as quatro atividades funcionais. Houve exacerbação da dor dos sujeitos após a realização das quatro atividades funcionais (p=0,01). Sendo assim, os resultados deste estudo, nas condições experimentais utilizadas, sugerem que não existe um padrão de comportamento em relação às variáveis baropodométricas estudadas que diferencie sujeitos com e sem SDPF durante as atividades de subir e descer escadas e rampa.

"A Comparative Study of Lower Extremity Angles Inpatients with Patello Femoral Pain Syndrome (PFPS)compared to Normal Subjects During Stancephase Of Gait Cycle"

Background: PFPS commonly leads to anterior or retro patellar knee pain. The etiology of PFPS is multi-factorial and various studies have identified abnormal patellar tracking, patellar malalignment, abnormal subtalar motion, decrease in navicular angle as some of the possible factors which might lead to PFPS. This comparative study investigates the lower extremity alignment during stance phase of gait cycle in subjects with and without patellafemoral pain syndrome.Methods: In this experimental study 14 male subjects suffering from PFPS were taken into Group A and 20 asymptomatic male subjects were taken into Group B. Video analysis of both groups were done in anterior, posterior and sagittal view. Still frames of initial contact, mid stance and terminal stance phases of the gait cycle and five angles i.e. standing foot angle, navicular angle, Q angle, A angle and rear foot angle for each of three phases were measured with image tool software.Results: The mean data showed that the standing foot angle, navicular angle, Q angle, A angle were increased in asymptomatic group when compared to the PFPS group in initial contact, mid stance and terminal stance but these increase in angles were not statistically significant. However the increase in rear foot angle in terminal stance of normal subjects compared to PFPS group was statistically significant (p value= 0.047)Conclusion: There exists an association of lower extremity angles with PFPS. Significant difference exists with respect to rear foot angle between PFPS and asymptomatic individuals. Rear foot angle decreases during the terminal stance in the PFPS subjects when compared to asymptomatic subjects

Kinematic and electromyographic analysis in patients with patellofemoral pain syndrome during single leg triple hop test

Possible delays in pre-activation or deficiencies in the activity of the dynamic muscle stabilizers of the knee and hip joints are the most common causes of the patellofemoral pain syndrome (PFPS). The aim of the study was to compare kinematic variables and electromyographic activity of the vastus lateralis, biceps femoris, gluteus maximus and gluteus medius muscles between patients with PFPS and health subjects during the single leg triple hop test (SLTHT). This study included 14 female with PFPS (PFPS group) and 14 female healthy with no history of knee pain (Healthy group). Kinematic and EMG data ware collected through participants performed a single session of the SLTHT. The PFPS group exhibited a significant increase (p<0.05) in the EMG activity of the biceps femoris and vastus lateralis muscles, when compared with the healthy group in pre-activity and during the stance phase. This same result was also found for the vastus lateralis muscle (p<0.05) when analyzing the EMG activity during the eccentric phase of the stance phase. In kinematic analysis, no significant differences were found between the groups. These results indicate that biceps femoris and vastus lateralis muscles mainly during the pre-activation phase and stance phases of the SLTHT are more active in PFPS group among healthy group.

Correlation between anterior knee pain with flexibility muscles hip

Introduction: The patellofemoral pain syndrome (PFPS) is one of the most common affections of the knee joints that has as one of its main functions the human locomotion, while the hip is the largest spherical joint of the human body. Objective: To know the correlation of anterior knee pain with hip flexibility and range of motion (ROM) in female academics. Method: A cross-sectional descriptive study was carried out with a population composed by 40 academics, divided into 2 groups of equal size, one composed by volunteers with PFPS and the other without the syndrome. The volunteers were aged between 18 and 30 years. For flexibility and ROM evaluation was used a fleximeter and a universal goniometer, respectively. Results: After statistical analysis, it was verified that the ROM of the hip abduction was decreased in the PFPS group, probably due to the retraction of the adductor muscles of the hip, or even by the loss of the muscular strength of them. With regard to flexibility, hip flexor muscles were retracted, with a significant difference comparing the group with pain and the group without anterior knee pain. Conclusion: It was shown that there are muscle changes related to flexibility and ROM in the flexor and hip abductor groups, respectively, in the volunteers with presence of Patellofemoral Pain Syndrome.

Intra- and Inter-session Reliability of Static and Dynamic Postural Control in Participants with and without Patellofemoral Pain Syndrome.

To determine the intra- and inter-session reliability of balance performance in people with patellofemoral pain syndrome (PFPS) and matched controls. In this methodological study, single-leg-stance performance of 15 participants with unilateral PFPS and 15 healthy matched controls was assessed using the Biodex Balance System (BBS) under 4 task difficulty levels (static and dynamic, with and without visual feedback). Intra-class correlation coefficients (ICCs), standard errors of measurement, and coefficients of variation were calculated for the overall stability index, anterior-posterior stability index, and medial-lateral stability index. Static and dynamic postural performance during single-leg stance showed moderate to very high reliability in the PFPS group (ICCs=0.53-0.96) and in healthy control participants (ICCs=0.51-0.91). Both measures were more reliable with eyes closed than with eyes open. BBS stability indices appear to have acceptable reliability in people with PFPS, particularly in more challenging conditions, and may be incorporated into the evaluation and rehabilitation of this patient group.

The Effect of Fatigue on the Biomechanics of Recreational Runners with Patellofemoral Pain

Patellofemoral pain syndrome (PFPS) is one of the most common injuries experienced by recreational runners. Pain is often absent at the beginning of activity, but tends to worsen with fatigue during a run. This may be due to the effect of fatigue on the magnitude of activation of muscles responsible for controlling hip and knee biomechanics, thus altering the loading environment of the patellofemoral joint and predisposing to PFPS pathology. PURPOSE: To compare the effects of fatigue on strength and muscle activation during an exhaustive run in female runners with and without PFPS. Kinematic and spatiotemporal variables were also examined as a means to understand the strength and muscle activation differences between groups. METHODS: Five females (33.5 +/-8.8 years of age) with a history of PFPS for > 2 months and five age-matched, healthy control females (32.8 +/-7.4 years of age) ran on a treadmill at a self-selected speed to a pre-determined level of fatigue (Rating of Perceived Exertion=17). Strength of the major hip muscles was measured pre- and post-run using handheld dynamometry. Surface EMG was recorded wirelessly from the following muscles: gluteus medius, tensor fascia lata, rectus femoris, and biceps femoris. EMG as well as kinematic and spatiotemporal data were collected at 3-minute intervals until termination. Comparisons were made between the 0%, 50%, and 100% intervals of the run using separate 2-way ANOVAs, with fatigue as the repeated measure for each variable of interest and post hoc Tukey HSD tests for significant main effects. RESULTS: Hip external rotation (ER) strength was significantly decreased in the PFPS group from pre- to post-run (mean difference = 0.09 Nm/kg, p = 0.045). Females with PFPS also demonstrated increased peak activation of gluteus medius. Peak hip internal rotation (IR) (mean difference = 3.44°, p = 0.291) and adduction (mean difference = 0.84°, p = 0.294) both trended toward an increase in the PFPS group from the beginning to the end of the exhaustive run. CONCLUSIONS: Females with PFPS exhibited decreased strength of hip external rotators following an exhaustive run compared to healthy, age-matched controls, which may be a factor in the increased hip IR angle in this group. EMG analysis revealed increased activation of gluteus medius. Greater activation levels may result in earlier fatigue to hip external rotators, leading to altered hip kinematics and a predisposition to PFPS.

Association between patellofemoral pain syndrome and hip morphology

Background: Patellofemoral pain syndrome (PFPS) is one of the most common conditions in the knee joint, there still unclear etiology.Objective: The objective of this study was to investigate the association of PFPS with the morphology of the hip. Method/Design: Forthis study were evaluated 41 university students aged between 18 and 30 years divided into group with PFPS and control group, inwhich we analyzed the distance from the anterior superior iliac spine (ASIS), length of the lower limbs (LL) away from the patella ASISbilaterally, lateral bending and iliac slope. Results: After data collection and subsequent tabulation, it was found that the group withPFPS showed contralateral iliac increase the pain (p = 0.01), moreover, was also found to the side of prevalence of pain is the side notdominant (p = 0.00). Conclusions: It can be inferred that there is little relationship between the morphological changes of the hip withthe PFPS, as only found a side tilt of the pelvis in volunteer group that reported a previous knee pain.

Effects of femoral rotational taping on pain, lower extremity kinematics, and muscle activation in female patients with patellofemoral pain.

To explore the hip and knee joint kinematics as well as muscle activation between participants with patellofemoral pain syndrome (PFPS) and controls, and to investigate the immediate effect of proximal femoral rotational taping on pain, joint kinematics, and muscle activation during single-leg squat (SLS). Cross-sectional study. Sixteen female participants with PFPS, and eight healthy female controls participated. Three-dimensional hip and patellar kinematics measured by electromagnetic tracking system, hip (gluteus maximus and gluteus medius) and thigh (rectus femoris) muscle activation measured by EMG, and subjective report of pain were recorded during SLS in three randomized conditions of no tape, sham taping, and femoral rotational taping with kinesiotape. Without taping, compared with controls, PFPS group had increased hip adduction angle (23.5±11.3° vs. 15.8±7.3°) during SLS. Additionally, PFPS group exhibited lesser rectus femoris activity during the initial 0-15° of SLS. Application of both femoral rotational and sham tapes reduced pain for PFPS group. Compared with no tape or sham tape, femoral rotational tape significantly shifted the patella into more posterior (1.59±0.83cm in no tape vs. 1.54±0.87cm in sham tape vs. 1.32±0.72cm in femoral rotational tape) and distal (-2.49±0.95cm vs. -2.64±0.80cm vs. -3.11±0.77cm) positions in the PFPS group. Femoral rotational taping could alter patellofemoral kinematics and decrease pain in treatment of young female participants with PFPS.

Muscle Activation Patterns and Patellofemoral Pain in Cyclists

Patellofemoral pain syndrome (PFPS) is pervasive and debilitating in the sport of cycling. Currently, little is known about the underlying mechanism causing patellofemoral pain in cyclists. The purpose of this study was to determine whether temporal differences in the muscle activity of the vastus medialis (VM), vastus lateralis (VL), semitendinosus (ST), and biceps femoris (BF) were correlated to patellofemoral pain in cycling. Ten healthy cyclists (six women and four men, height = 1.74 ± 0.10 cm, weight = 71.9 ± 16.5 kg, cycling experience = 199.5 ± 82 miles · wk(-1)) and seven cyclists with PFPS (one woman and six men, height = 1.84 ± 0.08 cm, weight = 89.8 ± 9.4 kg, cycling experience = 228 ± 51 miles · wk(-1)) volunteered to participate in this study. Each participant completed a 10-min cycling trial during which surface EMG was recorded for the VM, VL, ST, and BF muscles. Sagittal plane knee kinematic data were recorded using an electrogoniometer. An ANOVA revealed no significant difference between groups for the differences in onset times of the VM and VL (P = 0.805). There were significant differences between groups for the differences in offset time of the VM and VL (P = 0.032), the differences in onset time of BF and ST (P < 0.001), and the differences in offset time of the ST and BF (P = 0.024). Root mean square values for BF activity were significantly higher in the PFPS group compared with the control (CTL) group (P < 0.01), and ST values were significantly lower in the PFPS group compared with the CTL group (P < 0.01). Root mean square values for BF were significantly greater than ST activity in the PFPS group (P < 0.01) but not in the CTL group (P > 0.05). The results of this study indicate that trained cyclists with PFPS exhibit altered temporal characteristics in muscle activation patterns compared with trained cyclists without PFPS.

Clinical tests for differentiating between patients with and without patellofemoral pain syndrome

Abstract Patellofemoral pain syndrome (PFPS) is a very common knee condition with various aetiologies. Because of the nebulous factors of the syndrome, physiotherapists often find it difficult to assess and treat these patients. The aim of this study was to identify the clinical assessment tool that can differentiate PFPS patients from patients with other lower limb conditions. Fifty-two patients from the National Health System (26 with PFPS and 26 with other lower limb conditions) took part in this study. They underwent a series of strength, flexibility, and stress tests. Their pain levels were also recorded. The results showed that among the various clinical tests, only the hip flexion component of the Thomas test was able to differentiate between the two groups. In addition, the stress test showed that the PFPS group could not recover their gluteal muscle strength in the same way the group with the other lower limb conditions did. The Lower Extremity Functional Scale was found to be more able to differentiate between the two groups than the Anterior Knee Pain Scale. This study has shown that it is difficult to find specific clinical tests to diagnose PFPS. More research is needed in this important area.

Correlation between Intrinsic Patellofemoral Pain Syndrome in Young Adults and Lower Extremity Biomechanics.

[Purpose] The purpose of this study was to evaluate the correlation between intrinsic patellofemoral pain syndrome (PFPS) in young adults and lower extremity biomechanics. [Subjects] This experiment was carried out with sixty (24 men and 32 women), who are normal university students as subjects. [Methods] All subjects underwent 3 clinical evaluations. For distinguishing the intrinsic PFPS from controls, we used the Modified Functional Index Questionnaire (MFIQ), Clarke’s test and the Eccentric step test. Based on the results of the tests, subjects who were classified as positive for 2 more tests were allocated to the bilateral or unilateral intrinsic PFPS group (n=14), and the others were allocated to the control group (n=42). These two groups were tested for hamstring tightness, foot overpronation, and static Q-angle and dynamic Q-angle. These are the four lower extremity biomechanic, cited as risk factors of patellofemoral pain syndrome. [Results] The over pronation, static Q-angle and the dynamic Q-angle were not significantly different between the two groups. However, the hamstring tightness of the PFPS group was significantly greater than that of the controls. [Conclusion] We examined individuals for intrinsic patellofemoral pain syndrome in young adults and lower extremity biomechanics. We found a strong correlation between intrinsic PFPS and hamstring tightness.

Usefulness of magnetic resonance imaging in the evaluation of patellar malalignment

ObjectivesThe aim of this study is to evaluate the usefulness of magnetic resonance imaging (MRI) at 20° of knee flexion in patients with patellofemoral pain syndrome (PFPS) caused by suspected patellofemoral malalignment (PFM). Materials and methodsFifty MRIs were performed on 25 patients with PFPS secondary to suspected PFM based on clinical examination, and on 25 patients without PFPS (control group). Measurements were made of tibial tuberosity–trochlear groove distance (TTTG) and modified Laurin, Merchant and trochlear angles. The results were analyzed with ANOVA and Fischer's tests. Pearson's correlation coefficients were used to analyze differences between PFPS and control cases. Specificity, sensitivity, positive predictive value and negative predictive value for knee pain were documented. ResultsSignificant differences were observed between PFPS and control groups in TTTG (11.79mm vs. 9.35mm; P=.002), Laurin angle (12.17° vs. 15.56°; P=.05), and trochlear angle (139° vs. 130.02°; P=.049). No differences were found between groups as regards the merchant angle (P=.5). TTTG was 70% predictive of PFPS; however, it was only 53.33% specific, with a sensitivity of 51.61% for PFPS. Laurin angle was 77.78% predictive of PFPS, with a specificity of 92% and a sensitivity of 28%. Trochlear angle was 85.71% predictive of PFPS, with a specificity of 96% and a sensitivity of 24%. ConclusionsMRI can confirm clinically suspected PFPS secondary to malalignment. MRI determination of TTTG, patellar tilt, and trochlear angle correlates positively with clinical diagnosis of PFPS, suggesting that PFPS is caused by subtle malalignment.

Influence of exercises on patellar height in women with patellofemoral pain syndrome.

OBJECTIVE: To evaluate the patellar height of volunteers with and without patellofemoral pain syndrome (PPS) during maximal voluntary isometric contraction (MVIC) in open kinetic chain (OKC) and closed kinetic chain (CKC) exercises. METHODS: Twenty healthy women, and nineteen women with patellofemoral pain syndrome were evaluated and subjected to nuclear magnetic resonance imaging during rest and MVIC in OKC and CKC at 15°, 30°, and 45° knee flexion. The patellar height was assessed by the K-Pacs program,using the Insall-Salvati index. For each exercise and knee position, patellar height was measured three times and the procedure was repeated after seven days. RESULTS: These data did not confirm our hypothesis that OKC exercises promote increased patellar height. CONCLUSION: Patellar height is not associated with PPS and suggests that CKC exercises lead an increased patellar height during knee position at 15º and 45º flexion for the PPS group. Level of Evidence II, Comparative Prospective.

Utilidad de la resonancia magnética en la evaluación del mal alineamiento patelar

ObjectivesThe aim of this study is to evaluate the usefulness of Magnetic Resonance Imaging (MRI) at 20° of knee flexion in patients with patellofemoral pain syndrome (PFPS) caused by suspected patellofemoral malalignment (PFM). Material and methodFifty MRIs were performed on 25 patients with PFPS secondary to suspected PFM based on clinical examination, and on 25 patients without PFPS (control group). Measurements were made of tibial tuberosity-trochlear groove distance (TTTG) and modified Laurin, Merchant and trochlear angles. The results were analyzed with ANOVA and Fischer tests. Pearson correlation coefficients were used to analyze differences between PFPS and control cases. Specificity, sensitivity, positive predictive value and negative predictive value for knee pain were documented. ResultsSignificant differences were observed between PFPS and control groups in TTTG (11.79mm vs. 9.35mm; P=.002), Laurin angle (12.17° vs. 15.56°; P=.05), and trochlear angle (139° vs. 130.02°; P=.049). No differences were found between groups as regards the Merchant angle (P=.5). TTTG was 70% predictive of PFPS; however, it was only 53.33% specific, with a sensitivity of 51.61% for PFPS. Laurin angle was 77.78% predictive of PFPS, with a specificity of 92% and a sensitivity of 28%. Trochlear angle was 85.71% predictive of PFPS, with a specificity of 96% and a sensitivity of 24%. ConclusionsMRI can confirm clinically suspected PFPS secondary to malalignment. MRI determination of TTTG, patellar tilt, and trochlear angle correlates positively with clinical diagnosis of PFPS, suggesting that PFPS is caused by subtle malalignment.

Influência de diferentes tipos de calçado na atividade eletromiográfica do músculo quadríceps de mulheres ao subir e descer degrau

INTRODUÇÃO: A síndrome da dor femoropatelar (SDFP) é caracterizada por dor difusa na região retropatelar, aumentada durante realização de tarefas diárias, tais como subir e descer escadas e ajoelhar. A SDFP tem maior prevalência em mulheres jovens e sua etiologia não é totalmente conhecida. OBJETIVO: Avaliar a influência do uso de diferentes tipos de calçados na atividade dos músculos estabilizadores da patela durante as tarefas de subir e descer degrau. MATERIAIS E MÉTODOS: Participaram do estudo dez mulheres saudáveis e dez mulheres com SDFP. As voluntárias realizaram as tarefas de subir e descer um degrau em três situações: descalças, usando tênis e salto alto de 10 cm. Durante a realização das tarefas, foi registrada com eletrodos superficiais a atividade eletromiográfica dos músculos vasto medial oblíquo (VMO), vasto lateral (VL) e reto femoral (RF). A comparação intergrupos foi realizada com o teste t não pareado; para a análise intragrupo, utilizou-se ANOVA com medidas repetidas e post hoc Tukey, todos com um nível de significância de 5%. RESULTADOS: Os resultados demonstraram, no grupo controle, aumento da atividade do VMO nas tarefas concêntrica e excêntrica realizadas com salto alto. No entanto, no grupo SDFP, a atividade do VMO não foi influenciada em nenhuma das condições testadas. Não foram observadas diferenças estatísticas na razão VMO/VL e no tempo de ativação dos músculos. CONCLUSÃO: Os resultados sugerem que em mulheres assintomáticas uso do calçado de salto alto modificou a atividade de todos os músculos. Entretanto, mulheres com SDFP não apresentaram alterações no VMO.

Is there a relationship between tracking ability, joint position sense, and functional level in patellofemoral pain syndrome?

This prospective cohort study investigated proprioception and motor control changes in patients with patellofemoral pain syndrome (PFPS), and how these changes related to knee function, pain, muscle strength and muscle endurance. The study included 43 women diagnosed with unilateral patellofemoral pain syndrome. Thirty-one healthy women were recruited as control group. Peak quadriceps femoris and hamstring muscle isokinetic torques were recorded at 60 and 180°/s. Joint position sense was tested by active reproduction of joint position during horizontal squat performance. Muscle coordination and motor control ability were tested by a multi-joint lower limb tracking-trajectory test. Muscle endurance was tested using a computerized functional squat system. Severity of pain in during stair ascent/descent, squatting, and prolonged sitting with knees 90° flexed were measured using a 10 category modified visual analogue scale. Functional levels of patients were determined using Kujala patellofemoral scores. Active reproduction of joint position did not differ between PFPS and control groups. However, tracking-trajectory error was significantly higher in PFPS group than control subjects. Hamstring and quadriceps peak isokinetic torque and muscle endurance scores were significantly lower in the PFPS group. Kujala patellofemoral score displayed significant relationships with peak isokinetic quadriceps torque, knee pain, and joint position sense scores. Pain during stair descent, sitting, and quadriceps torque at 180°/s explained 57.7 % of the variation in Kujala patellofemoral score. Although lower extremity joint position sense did not differ between groups, the PFPS group displayed a target-trajectory muscular coordination deficit, decreased muscular endurance, and decreased muscular strength compared to control group subjects. Pain level directly related to motor control performance while joint position sense scores did not. Knee pain and impaired strength related more to functional performance impairment than joint position sense scores in patients with PFPS.

Onset of quadriceps activation and torque variation during stair ascent in individuals with patellofemoral pain

Introduction: Studies have used surface electromyography (EMG) to understand motor recruitment in individuals with patellofemoral pain syndrome (PFPS); however, there is no consensus in the literature. Objective: To understand if, in addition to neuromuscular disorders, there are changes in rotational patterns in individuals with PFPS. Methods: Twenty-two control pain-free subjects and eleven subjects with PFPS were assessed during stair ascent with respect to the onset of muscle activation and percentage of torque variation (PTV). Result: The PFPS group showed previous activation of vastus lateralis (VL) (21.1 ± 58.1ms), while simultaneous activation was observed in the control group (2.8 ± 30.7ms, p=0.01). The groups also showed differences in relation to the PTV (p=0.02): the control group showed greater variation in torque (26.7 ± 35.3%) compared to the PFPS group (17.5 ± 35.9%). Conclusion: People with PFPS have prior activation of VL and lower tendency towards body rotation, which may suggest patellar lateralization.