Biomechanical factors associated with patellofemoral pain in children and adolescents.

To investigate the biomechanical factors associated with patellofemoral pain in children and adolescents. A cross-sectional, population-based study conducted in Brazil from 2019 to 2023, involving students from public schools. Adjusted prevalence ratios and their respective 95% confidence intervals for the outcome in relation to independent variables were calculated for association analysis, adopting a significance level of 5%. Out of the total of 283 students, 152 were female and 182 were aged between 16 and 18 years old. A positive association was observed between the presence of patellofemoral pain and a poor movement quality in both lower limbs (right side: p = 0.04 and left side: p = 0.04) as well as with dynamic valgus of the left lower limb (p < 0.01). Patellofemoral pain in children and adolescents is associated with poor movement quality in the lower limbs and dynamic valgus of the left lower limb. Actions targeting these biomechanical factors may be crucial for early diagnosis and clinical treatment of this disfunction.

Effects of neuromuscular electrical stimulation on patellofemoral pain: A randomized controlled trial.

INTRODUCTION: Patellofemoral Pain (PFP) is a common dysfunction that can compromise the performance of daily activities. Neuromuscular electrical stimulation (NMES) has been proposed as a complementary tool in the therapeutic approach. OBJECTIVE: To analyze the effects of adding NMES to therapeutic exercises in women with PFP. METHODS: Randomized controlled trial involving 34 women with PFP (mean age 23.8 ± 4.1), randomly assigned to two groups: exercises combined with NMES (ESG) and exercises only (ExG). The ExG followed an exercise protocol, while the ESG performed the same exercises combined with NMES. Interventions were performed twice a week for eight weeks. Primary outcome measures included pain and functional disability, while secondary outcomes encompassed electromyographic activity of the quadriceps and hip abductors, along with isokinetic performance. Assessments were performed before the intervention, after 4 and 8 weeks from the start of the protocol and 8 weeks after the conclusion of the treatment. RESULTS: We did not observe difference between the groups in any of the analyzed variables. Both groups showed a reduction in pain and an improvement in functional disability during intragroup comparisons. CONCLUSION: A reduction in pain and an improvement in functional disability were observed; however, there was no additional effect of NMES. TRIAL REGISTRATION: NCT03918863.

Lower limb muscles' thicknesses are weakly associated with dynamic knee valgus during single-leg squat in women with patellofemoral pain.

INTRODUCTION: Patellofemoral pain (PFP) patients often show an altered lower limb alignment during the single-leg squat (SLS). There is evidence that proximal and distal-to-the-knee muscle alterations can modify the lower limb alignment in PFP patients. However, we observed a lack of studies investigating the possible association between the thickness and strength of proximal and distal-to-the-knee muscles and lower limb alignment during SLS in women with PFP. Therefore, this study aimed to investigate the association between the thickness and strength of lower limb muscles and dynamic knee valgus (DKV) during SLS in women with PFP. METHODS: Cross-sectional study, where fifty-five women with PFP were submitted to the following evaluations: (1) muscle thickness (MT) of Gluteus Medius (GMed), Gluteus Maximus (GMax), Vastus Lateralis (VL), and Tibialis Anterior (TA); (2) isometric peak torque of hip abductors, hip external rotators, knee extensors, and foot inversors; and (3) DKV during SLS. RESULTS: There was a significant negative association between GMax's MT and DKV (r = -0.32; p = 0.01), and between TA's MT and DKV (r = -0.28; p = 0.03). No significant correlations were observed between isometric torques and DKV. Regression analysis found that GMax's MT explained 10% of the DKV's variance during SLS. DISCUSSION: Poor lower limb alignment during SLS is weakly associated with proximal and distal-to-the-knee muscle thicknesses, with no association with isometric torque in PFP women. CONCLUSION: Our results suggest that other factors besides strength and muscle thicknesses may explain and improve lower limb alignment in women with PFP.

Are adjunct treatments effective in improving pain and function when added to exercise therapy in people with patellofemoral pain? A systematic review with meta-analysis and appraisal of the quality of interventions.

OBJECTIVE: To compare the effectiveness of adjunct treatments combined with exercise to exercise alone in people with patellofemoral pain (PFP) and explore the quality of intervention descriptions in randomised controlled trials (RCTs). DESIGN: Systematic review. DATA SOURCES: Seven databases were searched in November 2023. ELIGIBILITY: RCTs that evaluated the effectiveness of any adjunct treatment combined with exercise to exercise alone on self-reported pain and function in people with PFP. RESULTS: We included 45 RCTs (2023 participants), with 25 RCTs (1050 participants) contributing to meta-analyses. Pooled analysis indicated very low-certainty evidence that neuromuscular electrical stimulation or monopolar dielectric diathermy combined with exercise leads to small and large improvements in self-reported pain when compared with exercise alone (standardised mean difference (95% CI)=-0.27 (-0.53 to -0.02) and -2.58 (-4.59 to -0.57), respectively) in the short-term. For self-reported pain and function, very low-certainty evidence indicates that knee taping, whole-body vibration, electromyographic biofeedback and knee brace combined with exercise do not differ from exercise alone. Interventions are poorly described in most RCTs, adjunct treatments scored on average 14/24 and exercise therapy 12/24 in the Template for Intervention Description and Replication checklist. CONCLUSION: Neuromuscular electrical stimulation and monopolar dielectric diathermy combined with exercise seem to improve self-reported pain in people with PFP compared with exercise alone. Knee taping, whole-body vibration, electromyographic biofeedback and knee brace do not offer additional benefits to exercise alone. Most interventions are poorly described, which is detrimental to translating research knowledge into clinical practice. PROSPERO REGISTRATION NUMBER: CRD42020197081.

Validity and Reliability of an Arabic Version of the Survey Instrument for Natural History, Aetiology and Prevalence of Patellofemoral Pain Studies: A Cross-Sectional Study.

BACKGROUND AND OBJECTIVES: Knee pain, specifically patellofemoral pain (PFP), may lead to limitations in physical activity and social participation. Identifying knee pain that is attributed to PFP is not an easy job for healthcare professionals. To overcome this issue, The Survey Instrument for Natural History, Aetiology and Prevalence of Patellofemoral Pain (SNAPPS), which is a self-reporting questionnaire instrument, was designed to identify PFP in many languages. However, the Arabic version of the SNAPPS is not validated yet. This study was performed to assess the validity and reliability of the Arabic version of the SNAPPS (A-SNAPPS). MATERIALS AND METHODS: A cross-sectional study was conducted to achieve the study goals. To assess reliability, 38 participants were asked to complete the A-SNAPPS two times on the same day with a 30 min break in between. Convergent validity of the A-SNAPPS was assessed by exploring the correlations of the SNAPPS total score with the visual analogue scale (VAS) scores, including VAS for usual pain, VAS for worst pain, and VAS for pain during activities such as jumping, running, ascending and descending stairs, and squatting. RESULTS: The validity test findings suggested that SNAPPS has a strong correlation with the VAS during ascending and descending stairs (r = 0.71) and moderate correlations during jumping (r = 0.54) and squatting (r = 0.57). The test-retest reliability ICC was 0.92, indicating a very strong test-retest reliability of the A-SNAPPS. CONCLUSIONS: The A-SNAPPS was cross-culturally adapted and validated, demonstrating very strong reliability.

Effectiveness of Kinesio tape in the treatment of patients with patellofemoral pain syndrome: A systematic review and meta-analysis.

OBJECTIVE: To evaluate the clinical effectiveness of the Kinesio tape in the treatment of patellofemoral pain syndrome (PFPS) by meta-analysis. METHODS: Two investigators independently conducted an electronic literature search to assess the outcomes of intramuscular patches for PFPS. Electronic databases included PubMed, Embase, Web of Science, Cochrane Library, Wanfang Database, Chinese Journal Full Text Database (CNKI), and Wipo Database from November 2023. Extracted inclusion indicators included pain score VAS or NRS, knee function assessment knee pain syndrome (Kujala) score, and knee symptom score Lysholm knee score scale. Data were extracted and then meta-analyzed using Review Manager 5.3 software and Stata 17.0 software. RESULT: Fourteen studies were included, all of which were randomized controlled studies. The results showed that short-term pain relief was superior in the Kinesio tape (KT) group compared with the control group, with a statistically significant difference in the results (MD = -1.54, 95% CI [-2.32, -0.76], P = .0001); medium-term pain relief was superior in the KT group compared with the control group, with a statistically significant difference in the results (MD = -0.84, 95% CI [-1.50, -0.18], P = .01); long-term pain relief in the KT group was better than the control group, with statistically different results (MD = -0.56, 95% CI [-0.98, -0.13], P < .00001). In contrast, there was no significant difference between the KT group and the control group in the assessment of knee function (MD = -0.98, 95% CI [-4.03, 2.06], P = .03), and there was no significant difference between the KT group and the control group in the Lysholm knee score scale score of knee symptoms (MD = 4.18, 95% CI [-6.70, 15.05], P = .45). CONCLUSION: Kinesio taping can effectively relieve the pain of PFPS, but has no significant effect on the improvement of knee joint function and symptoms.

Analysis of lower limb muscle strength characteristics of amateur runners with patellofemoral pain: A cross-sectional study.

To analyze the lower limb muscle strength characteristics of amateur runners with patellofemoral pain (PFP). Sixty amateur runners (30 in the knee pain group, 30 in the control group) underwent measurements of hip abduction strength, knee extension strength, and knee flexion strength. Additionally, the hamstring/quadriceps ratio and limb strength symmetry index were calculated for all participants. Statistical analyses were conducted using linear mixed models. The hip abduction and knee extensors strength of amateur runners with PFP was significantly lower than that of the control group. The hamstring/quadriceps ratio was significantly higher in the male knee pain group compared to the control group, while no significant difference was found between the female knee pain group and the control group. Furthermore, both the hip abduction strength symmetry index and knee extensors symmetry index were significantly lower in the knee pain group compared to the control group. Amateur runners with PFP exhibit distinct lower limb strength characteristics compared to non-knee pain runners. Additionally, differences in lower limb strength characteristics between male and female amateur runners with PFP were observed. These findings emphasize the importance of considering functional and gender differences in PFP rehabilitation training.

Consensus methods in patellofemoral pain: how rigorous are they? A scoping review.

OBJECTIVE: Clinicians treating patients with patellofemoral pain (PFP) rely on consensus statements to make the best practice recommendations in the absence of definitive evidence on how to manage PFP. However, the methods used to generate and assess agreement for these recommendations have not been examined. Our objective was to map the methods used to generate consensus-based recommendations for PFP and apply four novel questions to assess the rigour of consensus development. DESIGN: Scoping review. DATA SOURCES: We searched Medline, SPORTDiscus, CINAHL and Embase from inception to May 2022 to identify consensus-derived statements or practice guidelines on PFP. The Joanna Briggs Institute Manual for Evidence Synthesis was followed to map the existing evidence. We measured the consensus methods based on four sets of questions addressing the panel composition, application of the consensus method chosen, agreement process and the use of evidence mapping. ELIGIBILITY CRITERIA: All consensus statements or clinical guidelines on PFP were considered. RESULTS: Twenty-two PFP consensus statements were identified. Panel composition: 3 of the 22 (14%) consensus groups reported the panellists' experience, 2 (9%) defined a desired level of expertise, 10 (45%) reported panellist sex and only 2 (9%) included a patient. Consensus method: 7 of 22 (32%) reported using an established method of consensus measurement/development. Agreement process: 10 of 22 (45%) reported their consensus threshold and 2 (9%) acknowledged dissenting opinions among the panel. Evidence mapping: 6 of 22 (27%) reported using systematic methods to identify relevant evidence gaps. CONCLUSIONS: PFP consensus panels have lacked diversity and excluded key partners including patients. Consensus statements on PFP frequently fail to use recognised consensus methods, rarely describe how 'agreement' was defined or measured and often neglect to use systematic methods to identify evidence gaps.

Impairments in peroneal muscle size and activation in individuals with patellofemoral pain in weight-bearing position.

BACKGROUND: Patellofemoral pain (PFP) is characterized by chronic pain in the anterior aspect of the knee during loading activities. Many studies investigating muscle morphology changes for individuals with PFP focus on the proximal joints, however, few studies have investigated muscles of the foot and ankle complex. This study aimed to explore the differences in peroneal muscle size and activation between individuals with PFP and healthy controls using ultrasound imaging in weight-bearing. METHODS: A case-control study in a university lab setting was conducted. Thirty individuals with PFP (age: 20.23 ± 3.30 years, mass: 74.70 ± 27.63 kgs, height: 161.32 ± 11.72 cm) and 30 healthy individuals (age: 20.33 ± 3.37 years, mass: 64.02 ± 11.00 kgs, height: 169.31 ± 9.30 cm) participated. Cross-sectional area (CSA) images of the peroneal muscles were taken in non-weight bearing and weight-bearing positions. The functional activation ratio from lying to single-leg standing (SLS) was calculated. RESULTS: There was a statistically significant (p = 0.041) group (PFP, healthy) by position (non-weight-bearing, weight-bearing) interaction for the peroneal muscle CSA with a Cohen's d effect size of 0.2 in non-weight-bearing position and 0.7 in weight-bearing position. The functional activation ratio for the healthy group was significantly more (p = 0.01) than the PFP group. CONCLUSION: Peroneal muscles were found to be smaller in size in those with PFP compared to the healthy subjects in the weight-bearing SLS position. This study found that those with PFP have lower activation of peroneal muscles in functional position.

Assessing quadriceps strength in patellofemoral pain patients: A study on the reliability and validity of a low-cost strain-gauge for clinical practice.

BACKGROUND: Patellofemoral pain (PFP) is a common knee complaint affecting diverse populations both acutely and chronically. Quadriceps muscle weakness is one possible aetiology, but current devices for measuring muscle strength (isokinetic dynamometer [ID] and hand-held dynamometers [HHD]) are frequently too expensive (e.g., ID) or lack reliability (e.g., HHD) for practitioners, especially in under-resourced settings. There is a need to evaluate a low-cost device to manage rehabilitation of people with PFP. METHODS: Isometric quadriceps strength of participants aged 18-35 years (total [n = 33], control group [n = 17] and PFP group [n = 16]) were evaluated on an isokinetic dynamometer and a commercially available strain gauge at baseline and after an 8-week non-standardised intervention. RESULTS: The strain gauge showed high absolute and relative reliability (intraclass correlation coefficient = 0.89-0.99; typical error of measurement = 3.9-10.4%). Clinically meaningful difference scores (12.2-45 Nm) were greater than the typical error of measurement, implying sufficient sensitivity of the strain gauge to measure true changes in isometric quadricep strength. Strong to very strong correlations were evident between the strain gauge and isokinetic dynamometer torque measurements (r = 0.88-0.90, SEE = 0.05-0.07 Nm), but slope values (ß = 0.65-0.77) indicated that torque from the strain gauge was lower than that obtained from the isokinetic dynamometer. An average systematic bias of 16.3-28.8 Nm was evident in favour of the isokinetic dynamometer, with no statistically significant between-group differences apparent between baseline and follow-up testing. CONCLUSION: The present commercially available strain gauge is reliable and sensitive enough to detect clinically meaningful differences in quadriceps strength of both healthy individuals and those with PFP. However, the strain gauge lacks validity and therefore cannot replace isokinetic dynamometry. Given the low cost and excellent reliability, the strain gauge can be a valuable tool to assess quadriceps muscle deficits and track rehabilitation progress in people with PFP.

Pain and disability were related to Y-balance test but not with proprioception acuity and single-leg triple-hop test in patients with patellofemoral pain: A cross-sectional study.

INTRODUCTION: Patellofemoral pain is a common complaint between physically active subjects. Patients with patellofemoral pain present limitations to performing daily activities. Pain could alter proprioceptive acuity and lead to movement impairment. The aim of this study was to investigate the relationship of pain and disability with proprioception acuity and physical performance in patients with patellofemoral pain. METHODS: Forty-eight patients with patellofemoral pain [age 31.15 (5.91) years; 30 (62.50%) males] were recruited. Data collected included pain intensity, pain duration, disability, joint position sense (JPS) test at 20° and 60° of knee flexion, and physical performance tests (Single-Leg Triple-Hop Test and Y- Balance Test). Spearman's rank correlation coefficient (rs) and 95% confidence intervals (CI) were computed to assess the relationship between the variables. RESULTS: Pain intensity was correlated with Y-Balance Test posteromedial component (rs = -0.32, 95%CI = -0.55 to -0.03, p = 0.029) and the composite score (rs = -0.35, 95%CI = -0.58, -0.07, p = 0.015). Pain duration was correlated with Y-Balance Test posterolateral component (rs = -0.23, 95% CI = -0.53 to -0.01, p = 0.047). Disability was correlated with Y-Balance Test posteromedial component (rs = 0.41, 95% CI = 0.14 to 0.62, p = 0.004). Pain and disability were not correlated with JPS and the Single-Leg Triple-Hop Test. CONCLUSION: Pain and disability were related to Y-Balance Test but not to proprioceptive acuity and Single-Leg Triple-Hop Test in patients with patellofemoral pain.

Effect of soft tissue tension around the knee joint on medio-lateral patellar position.

Patellofemoral pain (PFP) is one of the most common sports injuries of the knee joint and has a high persistence and recurrence rate. Medio-lateral patellar position in the knee extension position during contraction is associated with PFP. However, soft tissue tension that most influences the medio-lateral patellar position in the knee extension position during contraction in vivo is unclear. We aimed to clarify the relationship between medio-lateral patellar position and soft tissue tension around the knee joint. Twelve patients with PFP and 20 healthy participants were included. Medio-lateral patellar position and tension of the rectus femoris, vastus lateralis (VL), vastus medialis, iliotibial band (ITB), lateral patellofemoral ligament, and medial patellofemoral ligament were measured during contraction and rest. The tensions of the VL and ITB during contraction and the medio-lateral patellar position at rest were significantly associated with medio-lateral patellar position during contraction (ß = 0.449, 0.354, and 0.393, respectively). In addition, the tension of ITB was significantly associated with the medio-lateral patellar position at rest (ß = 0.646). These relationships were not affected by the presence of PFP. These findings suggest that the patellar position during contraction became more lateral as the tension in the VL and ITB increased, regardless of the presence of PFP. These results may facilitate the prevention and treatment of PFP.

Effect of adding short foot exercise to hip and knee focused exercises in treatment of patients with patellofemoral pain syndrome: a randomized controlled trial.

BACKGROUND: Patellofemoral pain syndrome is considered a common cause of anterior knee pain that could disturb function and limit daily activities. The purpose of the study was to investigate the effect of adding short foot exercise on pain, function, balance, and hip abductors, and quadriceps muscles strength in the treatment of patients with patellofemoral pain syndrome. METHODS: Twenty-eight male and female patients with patellofemoral pain syndrome with age ranged from 18 to 35 years old participated in this study. They were equally and randomly assigned into two groups; the study group which received short foot exercise in addition to hip and knee exercises (n = 14) and thecontrol group which received hip and knee exercises only (n = 14). Participants received their interventions during 6 consecutive weeks (12 sessions). Pain intensity, function, abductors quadriceps muscle strength, and balance were assessed using the Visual Analog Scale, anterior knee pain scale (AKPS), hand-held dynamometer, and the Biodex Balance System respectively. All measurements were taken before and after 6 weeks of intervention in both groups. Multivariate analysis of variance was performed to compare the within and between groups effects for measured variables. RESULTS: The within-group comparison showed significant improvement in pain severity, function, balance, and hip abductors, and quadriceps muscles strength in both groups post-treatment compared with pre-treatment. Between groups analysis, however, showed no significant statistical difference between both groups in all variables, except in pain, function, and mediolateral stability which showed better improvement compared to the control group. CONCLUSIONS: Adding short foot exercise to hip and knee exercises improved pain, function, and mediolateral stability in patients with patellofemoral pain syndrome. TRIAL REGISTRATION: clinicaltrials.gov. NO: NCT05383781. Date 19/ 5/2022.

The effect of high-intensity laser therapy on pain and lower extremity function in patellofemoral pain syndrome: a single-blind randomized controlled trial.

Patellofemoral pain syndrome (PFPS) is a set of symptoms that negatively affect the daily life activities of the individual, leading to functional disability and significant loss of labor, especially in young adults. PFPS is usually due to weakness of the vastus medialis obliquus (VMO) resulting in abnormal patellar tracking and pain. Our study aims to compare the efficacy of high-intensity laser therapy (HILT) on pain and lower extremity function in the treatment of PFPS with different electrophysical agents (EPAs). The study was designed as a single-blind randomized controlled trial. Forty-five people with PFPS (aged 25-45 years) were included in the study. The patients were randomly divided into three groups and a total of ten sessions of treatment were administered to all three groups for 2 weeks, 5 days a week. High-intensity laser (HILT) and exercise program were applied to group 1. Ultrasound (US), transcutaneous electrical nerve stimulation (TENS), and exercise program were applied to group 2. In group 3, US, interferential current (IFC), and exercise program were applied. Both groups underwent three evaluations: pre-treatment, post-treatment, and 12 weeks after treatment. Outcome measures included the visual analog scale for pain severity (VAS), knee flexion range of motion (FROM), Q angle, pain threshold, muscle strength of quadriceps and hamstring, Kujala patellofemoral scoring, lower extremity functional scale (LEFS), and Timed Up and Go Test (TUG). The ANOVA was used for comparing the data of the groups, and two-way repeated measure ANOVA was used to compare at the pre-post and post-intervention 3rd month. The LSD and Bonferroni post hoc tests were also used to identify the between-group differences. Groups 2 and 3 were statistically effective in pain and functionality (p < 0.05). Group 1 was found to be statistically more effective than other groups in reducing pain (95% confidence interval (CI), 0.000/0.000; p = 0.000), increasing knee flexion angle (95% CI, 127.524/135.809; p = 0.000), and increasing lower extremity function (95% CI, 75.970/79.362; p = 0.000). This study indicated that high-intensity laser therapy was found to be a more effective method in the treatment of patellofemoral pain syndrome after 3 months of follow-up compared to US-TENS combination and US-interferential current combination treatments. Also, HILT can be used as an effective method in combination with an appropriate exercise program including vastus medialis strengthening to reduce pain and increase functionality in the patients with PFPS.

Clinical value of questionnaires & physical tests for patellofemoral pain: Validity, reliability and predictive capacity.

OBJECTIVES: To determine the most appropriate method of functional assessment for "patellofemoral pain" (PFP)/"chondromalacia patella" for its diagnostic value, (validity, reliability, sensitivity, specificity, predictive value and clinical applicability); to outline initial interpretations of the questionnaires and their appropriateness, through the cut-off points determined in their scores based on physical test and Magnetic Resonance Imaging (MRI); to establish which methods should be used in conjunction with each other to obtain clinical diagnoses that are robust effective and efficient. METHODS: (1)Intra- and inter-observer reliability and of the relationship among PFP questionnaires/physical tests validated. (2)Predictive capacity of the questionnaires. Subject: 113 knees with PFP, assessed using "Knee-injury-and-Osteoarthritis Outcome-Score-for-Patellofemoral-pain-and-osteoarthritis" (KOOS-PF), "Kujala-Patellofemoral-Score" (KPS), "Victorian-Institute-of-Sports-Assessment-for-Patellar-tendons-questionnaire" (VISA-P), and the physical tests: "patellar-palpation", "patellar-tilt", "patellar-apprehension", "Clarke" and "squat". RESULTS: Questionnaires correlations themselves was 0.78

Patellofemoral pain syndrome in children and adolescents: A cross-sectional study.

OBJECTIVES: To assess the prevalence and associated factors of Patellofemoral Pain Syndrome (PFPS) in children and adolescents. METHOD: A population-based cross-sectional study was conducted with children and adolescents aged 10 to 18 years, who presented a history of peripatellar and/or retropatellar pain, attending elementary or high school in urban public schools in Natal, Brazil. The sample size was calculated based on a minimum outcome prevalence of 22%. RESULTS: A prevalence of 24.7% of PFPS was found. There was a positive association of PFPS with active students (p < 0.01; PR: 2.5; CI: 1.4-4.5), low functional capacity (p < 0.01; PR: 8.0; CI: 5.0-12.8), and those classified as pubertal (p < 0.03; PR: 1.8; CI: 1.0-3.2). CONCLUSION: There was a considerable prevalence of PFPS in children and adolescents, as well as an association between the level of sexual maturation and adjustable determinants, such as the level of physical activity and low functional capacity in this group.

Acute effects of negative heel shoes on perceived pain and knee biomechanical characteristics of runners with patellofemoral pain.

BACKGROUND: To determine the effects of negative heel shoes on perceived pain and knee biomechanical characteristics of runners with patellofemoral pain (PFP) during running. METHODS: Sixteen runners with PFP ran in negative (-11 mm drops) and positive (5 mm drops) heel shoes while visual analog scale (VAS) scores, retroreflective markers, and ground reaction force were acquired by applying a 10-cm VAS, infrared motion capture system, and a three-dimensional force plate. Knee moment, patellofemoral joint stress (PFJS), and other biomechanical parameters during the stance phase were calculated based on inverse dynamics and a biomechanical model of the patellofemoral joint. RESULTS: The foot inclination angle, peak PFJS during the stance phase, patellofemoral joint reaction force, knee extension moment, and quadriceps force at the time of peak PFJS of runners with PFP in negative heel shoes were lower than that in positive heel shoes, no significant difference was found in VAS scores, knee flexion angle, patellofemoral contact area, and quadriceps moment arm at the time of peak PFJS. CONCLUSIONS: Compared to positive heel shoes, running in negative heel shoes decreases peak PFJS in runners with PFP, which may decrease patellofemoral joint loading, thus reducing the possibility of further development of PFP. TRAIL REGISTRATION: Sports Science Experiment Ethics Committee of Beijing Sport University. 2023095H, April 18, 2023 (prospectively registered).

The effect of marathon running on the lower extremity kinematics and muscle activities during walking and running tasks.

Patellofemoral pain syndrome (PFPS) is a common injury among runners, and it is thought that abnormal lower extremity biomechanics contribute to its development. However, the relationship between biomechanical changes after a marathon and PFPS injury remains limited. This study aims to investigate whether differences in knee and hip kinematics and lower extremity muscle activities exist in recreational runners before and after a marathon. Additionally, it aims to explore the relationship between these biomechanical changes and the development of PFPS injury. 12 recreational runners participated in the study. Kinematics and muscle activities of the lower extremity were recorded during walking (5 km/h) and running (10 km/h) tasks within 24 hours before and within 5 hours after a marathon. After the marathon, there was a significant decrease in peak knee flexion (walking: p = 0.006; running: p = 0.006) and an increase in peak hip internal rotation (walking: p = 0.026; running: p = 0.015) during the stance phase of both walking and running compared to before the marathon. The study demonstrates a decrease in knee flexion and an increase in hip internal rotation during the stance phase of gait tasks after completing a marathon, which may increase the risk of developing PFPS injury.

Lumbopelvic manipulation alone versus combined with dry needling in physically active patients with patellofemoral pain syndrome: A randomized clinical trial.

INTRODUCTION: Patellofemoral pain syndrome (PFPS) is prevalent in physically active people. The multifactorial nature of PFPS necessitates multimodal treatment for this condition. The present study aimed to compare the efficacy of lumbopelvic manipulation alone versus manipulation plus dry needling in physically active patients with PFPS. METHOD: Thirty patients (18 women and 12 men) with a diagnosis of PFPS entered this randomized controlled clinical trial and were divided into two groups: lumbopelvic manipulation alone or lumbopelvic manipulation plus dry needling. The interventions were applied for 3 sessions every other day. Dry needling was performed on the quadratus lumborum and gluteus medius muscles. Pain intensity, Kujala score and side-plank time were recorded at baseline, post-intervention and 1 month after the intervention. RESULTS: The results of Friedman's test showed statistically significant differences in pain and function in participants during the study period, and post hoc tests revealed differences between the two groups in behavior of the marginal means (p < 0.001). CONCLUSION: The use of lumbopelvic manipulation plus dry needling in the quadratus lumborum and gluteus medius muscles may be more effective than manipulation alone in alleviating pain and promoting function in physically active patients with PFPS.

The effect of kinetic factors of dynamic knee valgus on patellofemoral pain: A systematic review and meta-analysis.

The speculation of dynamic knee valgus (DKV) correlates with kinetic changes in the frontal plane that increased loading patellofemoral joint (PFJ). Therefore, it is the purpose of this systematic review and meta-analysis study is the effect of kinetic factors DKV on patellofemoral pain (PFP). The search strategy was carried out in the electronic databases of Cochrane Library, PubMed, Springer Link, Science Direct, Scopus. Studies limited to the period 2000 to 2020 were extracted. The quality of study was assessment by modified Downs and Black checklist. Mean and standard deviation were also used to calculate the effect size. There were selected 8 articles for the systematic review and Meta-analysis. The results showed that in PFP patients compared to healthy individuals have increase knee abduction moment (SMD = 0.75; 95% CI = [0.47 to 1.02]) and impulse (SMD = 0.79; 95% CI = [0.50 to 1.07]). Furthermore, PFP patients compared to healthy individuals have decrease onset (SMD = -0.60; 95% CI = [-1.03 to -0.17]) and during (SMD = -0.93; 95% CI = [-1.57 to -0.29]) gluteus medius (GMED); vis-à-vis, PFP patients compared to healthy individuals have increase onset (SMD = 0.10; 95% CI = [-0.34 to 0.54]) and during (SMD = 0.29; 95% CI = [-0.15 to 0.73]) adductors longus (AL). As a result; PFP patients compared to healthy individuals show decrease co-contraction GMED/AL (SMD = -1.03; 95% CI = [-1.83 to -0.24]). The kinetic factors of DKV of leading to PFJ contact area decreases and the loading in a smaller contact area on PFJ in the outer part of the patella. Eventually, this abnormal distribution of contact pressure leads to etiology and osteoarthritis of the PFP.