Patellofemoral Pain Syndrome Group Research Articles

Lumbo-Pelvic-Hip Complex Endurance and Diaphragm Contractility in Females with Patellofemoral Pain Syndrome: A Case-Control Study

Background: The diaphragm muscle constitutes the internal component of the Lumbo-Pelvic-Hip Complex (LPHC), and its stability is suggested to influence lower limb joint function, particularly the alignment of the patellofemoral joint and the tracking path mechanism of the patella. Objectives: To compare the endurance of the LPHC and diaphragm contractility in females with patellofemoral pain syndrome (PFPS) and a healthy control group. Methods: Fifty-six females, including twenty-eight diagnosed with patellofemoral pain syndrome and twenty-eight healthy females matched as controls (aged 15 - 45), were invited to participate in this case-control study. Endurance scores of trunk extensor, flexor, and lateral flexor muscles, endurance ratios, and the percentage of diaphragm muscle contractility using the ultrasonography method were compared between the two groups. Results: The endurance time of trunk flexors and right and left lateral muscle groups in the PFPS group significantly differed compared to the control group (P < 0.05). Diaphragm contractility in both the right (Mean ± SD: 21.82 ± 3.61; P < 0.001) and left (Mean ± SD: 22.92 ± 2.99; P = 0.007) sides was significantly lower in the PFPS group compared to the control group. Conclusions: Lumbo-Pelvic-Hip Complex stability and diaphragm respiratory function and contractility were impaired in females with PFPS.

Sagittal trunk excursion and lumbar repositioning error between female and male patients with patellofemoral pain syndrome.

Patellofemoral pain syndrome (PFPS) is a challenging clinical problem affecting adults, adolescents, and physically active populations. PFPS impacts the patient's trunk kinematics in the frontal plane. Previous studies have found gender-based biomechanical differences in patients with PFPS; however, sagittal trunk kinematics during mini-squats and lumbar proprioception in PFPS have not been studied previously. To investigate sagittal trunk excursion (It is defined as the sagittal trunk flexion angle from the start to the end of the mini squat) during mini-squats as well as lumbar repositioning error between individuals with and without PFPS, and determine gender differences in the outcome variables. A sample of 56 participants aged 18-25 years was enrolled; 30 with PFPS (13 males, 17 females) and 26 asymptomatic controls (11 males, 15 females). The sagittal trunk excursion during mini-squats was examined by two-dimensional (2D) photographic analysis using Surgimap software. Active lumbar flexion repositioning error was assessed using an isokinetic dynamometer. For sagittal trunk excursion, no significant main effect of group was observed (). On the other hand, the main effect was significant for gender (), as was the interaction effect. Compared to the control group, the PFPS group showed significantly () lower sagittal trunk excursion in females than in males during mini-squats. For active lumbar flexion repositioning error, no evidence was found for significant main or interaction effects (). Females with PFPS exhibit a more erect sagittal trunk posture than males during mini-squats. Trunk posture should be considered during weight-bearing activities in PFPS, and gender-specific assessment protocols should be developed.

The Relationship between Patellofemoral Pain Syndrome and Hip Biomechanics: A Systematic Review with Meta-Analysis

(1) Background and purpose: Muscular control and motor function in a patient with Patellofemoral pain syndrome (PFPS) have not yet been investigated systematically. Therefore, this review synthesis the previous results about the association of PFPS with gluteus muscle activation, hip strength, and kinematic characteristic of the hip and knee joint, to deepen understanding of the PFPS etiology and promote the establishment of an effective treatment strategy. (2) Methods: A literature search was conducted from January 2000 to July 2022 in four electronic databases: Medline, Embase, Google scholar, and Scopus. A total of 846 articles were initially identified, and after the screening process based on the inclusion criteria, 12 articles were eventually included. Means and SDs of gluteus medius (GMed), gluteus maximus (GMax), hip strength, and kinematic variation of hip and knee were retrieved from the present study. (3) Results and conclusion: Regarding kinematic variation, moderate evidence indicates that an increased peak hip adduction was found in PFPS groups during running and single leg (SL) squat activities. There is no difference in the GMed and GMax activation levels between the two groups among the vast majority of functional activities. Most importantly, strong evidence suggests that hip strength is weaker in individuals with PFPS, showing less strength of hip external rotation and hip abduction compared to the control group. However, without prospective studies, it is difficult to determine whether hip strength weakness is a cause or a result of PFPS. Therefore, further research is needed to evaluate the hip strength level in identifying individuals most likely to associated with PFPS development is needed.

The relationship between ankle dorsiflexion range of motion, frontal plane projection angle, and patellofemoral pain syndrome

BackgroundAnkle range of motion abnormalities have been often linked with alteration in knee kinematics leading to the development of patellofemoral pain syndrome (PFPS). Literature exploring the relationship between ankle dorsiflexion range of motion (DF ROM) and knee kinematics during functional tasks is scanty. This study aims to assess the relation between ankle DF ROM and frontal plane projection angle (FPPA), one of the knee kinematic variables, in individuals with and without PFPS during a step-down test. MethodsThis is a case-control study in which seventy PFPS patients and other 70 asymptomatic control subjects had their ankle DF ROM measured using an inclinometer with the knee flexed and extended. Their FPPA angles were measured using Kinovea software while doing the step-down test. ResultsWhen the two groups were compared, ankle DF ROM measured with the knee flexed was higher in the control group (33.15 ± 4.96) than in the PFPS group (30.20 ± 6.93) (p = 0.03). In both the PFPS group and the control group, the correlation between FPPA and ankle DF ROM with the knee flexed was statistically insignificant (p = 0.075 and 0.323 respectively). ConclusionDecreased ankle DF ROM can be one of the contributing factors to the development of PFPS in the context of greater dynamic knee valgus.

Effects of Patellofemoral Pain Syndrome on Changes in Dynamic Postural Stability during Landing in Adult Women.

Background This study investigated the effects of lower limb movements on dynamic postural stability (DPS) during drop landing in adult women with patellofemoral pain syndrome (PFPS). Methods Thirty-eight adult women were recruited and divided into two groups, the PFPS group and the control group. The study participants performed a single-leg drop landing from a 30 cm box, and their lower limb movements and DPS were measured. Differences between groups were examined using independent sample t-tests. In addition, stepwise multiple linear regression was used to examine the kinematic parameters that contribute to the DPS. Results The PFPS group had significantly lower hip flexion, internal rotation, knee flexion, ankle external rotation, pelvic oblique, tilt, rotation, and higher hip abduction, knee valgus, and ankle plantarflexion. In terms of DPS, the PFPS group had a significantly higher anteroposterior and a lower mediolateral than that of the control group. In the control group, regression analysis revealed a controlled anteroposterior using knee flexion, while the PFPS group controlled mediolateral through ankle plantarflexion. Conclusions Patients with PFPS experienced more shock on their knee joint during landing than patients in the control group with greater anteroposterior instability and lower mediolateral instability.

Electromyography Activity of Vastus Medialis Obliquus and Vastus Lateralis Muscles During Lower Limb Proprioceptive Neuromuscular Facilitation Patterns in Individuals with and without Patellofemoral Pain Syndrome.

Exercise therapy to strengthen quadriceps muscle is recommended in rehabilitation program for people with patellofemoral pain syndrome (PFPS). This study aimed to investigate the electromyography (EMG) activity of vastus medialis obliquus (VMO), vastus lateralis (VL) and VMO/VL ratio during PNF in individuals with and without PFPS. 26 persons with PFPS and 26 healthy subjects participated to study. All subjects performed PNF patterns (Flexion-Adduction-External Rotation (D1FL), Extension-Adduction-External Rotation (D2EX), D1FL+ load, D2EX+ load) and straight leg raise (SLR). The normalized EMG activity of VMO, VL and VMO/VL ratio were measured and analyzed using repeated measure ANOVA. There were significant main effects of group and exercises for the both VMO and VL (p<0.05). It was found that except SLR and D2EX, in the other motions PFPS group had lower VMO activity compared to healthy group (p<0.05). For VL except SLR, in the other motions PFPS group had lower VL activity too (p<0.05). The PNF patterns activated VMO more than SLR, however it was not significant (p>0.05). Also; there weren't any significant difference between the two groups in VMO/VL activation ratios. Also, performing the PNF patterns with load increased VMO and VL muscles activity significantly (p<0.05). It also found that in PFPS group the VMO/VL ratio values in PNF patterns were significantly more than SLR and the highest VMO/VL ratio value (0.96) was found during D2EX. The PNF patterns due to provide optimal VMO/VL ratio value than SLR and proper balance between these two muscles can be recommended in rehabilitation of individuals with PFPS.

Intra- and Inter-Session Reliability of Methods for Measuring Reaction Time in Participants with and without Patellofemoral Pain Syndrome.

To evaluate the relative and absolute reliability of reaction time measuring methods during different conditions in participants with and without patellofemoral pain syndrome (PFPS). 30 patients with PFPS and 30 healthy controls were recruited in the present study. The upper extremity reaction time, upper extremity error rate, involved and non-involved lower extremity braking reaction times, and involved and non-involved knee extension reaction times were measured. Each condition was repeated three times, 2 sessions with a 5-7 days interval. The intra-session reliability was evaluated in three-trial (A), second- and third-trial (B) modes. In addition, the inter-session reliability was evaluated in mode A, mode B, and best score (C) mode. The result of inter-session reliability of mode A showed that all measurements except upper extremity reaction time in PFPS group showed high to very high relative reliability (ICC: 0.74-0.94). In mode B, all measurements except non-involved knee extension reaction time in PFPS group showed high to very high relative reliability (ICC: 0.71-0.93). In mode C, all measurements showed high to very high relative reliability (ICC: 0.70-0.94) except upper extremity error rate and non-involved knee extension reaction time in PFPS group. The result of intra-session reliability showed that all measurements had high to very high relative reliability (ICC: 0.78-0.94) in mode A. In mode B, all measurements showed high to very high relative reliability (0.78-0.94). The braking time seems more reliable than other reaction time tasks. In addition, the results showed that mode A is more reliable than other modes. The newly designed package is a reliable tool to measure the knee extension reaction time in patients with knee musculoskeletal disorders.

Comparison of Knee Muscle Strength and Ankle Dorsiflexion Range of Motion Between Standing Workers With and Without Patellofemoral Pain Syndrome

Background: Prolonged standing during work causes a lower extremity pain and disorders. Patellofemoral pain syndrome (PFPS) is one of the common diagnoses of the knee pain. Although the etiology of PFPS is not completely understood, it is considered to be multifactorial. Objects: The purpose of this study was to investigate difference in strength of knee muscles, quadriceps:hamstring muscles strength ratio (Q:H ratio), asymmetry ratio of knee muscles strength and dorsiflexion range of motion (ROM) between standing workers with and without PFPS. Methods: Twenty-eight standing workers with PFPS and 26 age-, height-, and weightmatched standing workers without PFPS participated in this study. A tension sensor measured knee muscle strength, and motion sensor measured dorsiflexion ROM. The asymmetry ratio of knee muscles was calculated by a specific formula using the knee muscles strength of the dominant side and the sound side. An independent t-test was used to identify significant differences in the strength, ROM, Q:H ratio, and asymmetry ratio between the PFPS and normal groups. Results: The standing worker with PFPS have significantly lower dorsiflexion ROM (p < 0.000) and higher asymmetry ratio of the hamstring muscles strength (p < 0.000) compare to the standing worker without PFPS. No significant differences were seen in the strength of quadriceps muscle and hamstring muscles, Q:H ratio, and asymmetry ratio of quadriceps muscle strength. Conclusion: There was a significant difference in the asymmetry ratio of the isometric hamstring muscle strength. This finding suggests that the asymmetry ratio of isometric hamstring muscle strength may be more important than measuring only the hamstring muscle strength of the PFPS side. Furthermore, the results of this study showed a significant difference in dorsiflexion ROM between the standing industrial workers with and without PFPS. Dorsiflexion ROM and isometric hamstring muscle strength should be considered when evaluating the subjects with PFPS.

What Is the Effect on Kinesio Taping on Pain and Gait in Patients With Patellofemoral Pain Syndrome?

IntroductionPatellofemoral pain syndrome (PFPS) is one of the leading causes of anterior knee pain treated by orthopedists and physical therapists. This syndrome predominantly affects young, active individuals, and remains a challenging syndrome to manage due to the lack of quantitative diagnostic criteria to monitor during treatment. The etiology of this syndrome is believed to be multifactorial, with the gait and movement patterns of a patient potentially contributing to pain due to increased stress on the knee. In this study, we investigated the gait of participants with PFPS using the GaitRite system (CIR Systems Inc., Clifton, NJ) before and after the application of Kinesio Tape in order to assess the impact of Kinesio Tape on cadence, stance time, and pain.MethodsA convenience sample of 10 participants were recruited for this study, with five participants without PFPS serving as controls, and five with PFPS in the Kinesio Tape group. Participants in the Kinesio Tape groups served as their own internal control, ambulating both before and after taping. All participants ambulated across the GaitRite carpet three times and completed a visual analogue scale pain score for each trip.ResultsThe results of our study found there to be no significant difference in the cadence for gait between the participants without PFPS and participants with PFPS (105.2 seconds vs. 105.1 seconds, p = 0.272), or in the stance time between the control and PFPS group (1.43 seconds vs. 1.44, p = 0.907). Similarly, no significant difference was found in participants with PFPS before and after Kinesio Taping in the cadence and stance times (105.1 seconds vs. 107.4 seconds, p =0.288, and 1.44 vs. 1.40, p = 0.272). There was a significant difference in pain in PFPS participants before and after taping, with a 112.5% reduction in pain reported after taping (3.4 vs. 1.6, p < 0.05).Discussion and conclusionThis study is one of the first studies to utilize the GaitRite system in order to analyze the impact of Kinesio Tape on gait in participants with PFPS. While our study failed to demonstrate a significant difference in the gait of participants with PFPS in comparison to those without PFPS, we did demonstrate a significant reduction in pain after the application of Kinesio Tape. These results suggest other variables addressed by the Kinesio Tape may be causing the pain associated with PFPS.

Patellofemoral Pain Syndrome and Pain Severity Is Associated With Asymmetry of Gluteus Medius Muscle Activation Measured Via Ultrasound

The aim of the study was to determine whether gluteus medius muscle thickness or activation differed between left and right sides and was associated with patellofemoral pain presence or severity. Males and females were recruited and screened by a physiotherapist for inclusion in the control or patellofemoral pain syndrome group. Bilateral measures were obtained for Q angle and gluteus medius muscle thickness at rest and on contraction via standing hip external rotation, using ultrasound. Muscle activation was calculated as the percentage change in muscle thickness on contraction relative to at rest. Patellofemoral pain syndrome participants completed the anterior knee pain scale and a visual analog pain scale. Gluteus medius muscle thickness at rest and on contraction, muscle activation, and Q angle were not different between control (n = 27, 63% female) and patellofemoral pain syndrome (n = 27, 59% female) groups. However, patellofemoral pain syndrome participants had a significantly larger left-right side imbalance in gluteus medius muscle activation than controls (15.9 ± 19.3% vs. 4.4 ± 21.9%, P < 0.05). Among patellofemoral pain syndrome participants, the magnitude of asymmetry of gluteus medius muscle activation was correlated with knee pain score (r = 0.425, P = 0.027). Asymmetry of gluteus medius muscle activation was associated with patellofemoral pain syndrome and pain severity. This is clinically relevant for patellofemoral pain syndrome prevention and treatment, particularly because this was quantifiable using ultrasound.

Classifying individuals with and without patellofemoral pain syndrome using ground force profiles – Development of a method using functional data boosting

BackgroundPredictors of recovery in patellofemoral pain syndrome (PFPS) currently used in prognostic models are scalar in nature, despite many physiological measures originally lying on the functional scale. Traditional modelling techniques cannot harness the potential predictive value of functional physiological variables. Research questionWhat is the classification performance of PFPS status of a statistical model when using functional ground reaction force (GRF) time-series? MethodsThirty-one individuals (control = 17, PFPS = 14) performed maximal countermovement jumps, on two force plates. The three-dimensional components of the GRF profiles were time-normalized between the start of the eccentric phase and take-off, and used as functional predictors. A statistical model was developed using functional data boosting (FDboost), for binary classification of PFPS statuses (control vs PFPS). The area under the Receiver Operating Characteristic curve (AUC) was used to quantify the model’s ability to discriminate the two groups. ResultsThe three predictors of GRF waveform achieved an average out-of-bag AUC of 93.7 %. A 1 % increase in applied medial force reduced the log odds of being in the PFPS group by 0.68 at 87 % of jump cycle. In the AP direction, a 1 % reduction in applied posterior force increased the log odds of being classified as PFPS by 1.10 at 70 % jump cycle. For the vertical GRF, a 1 % increase in applied force reduced the log odds of being classified in the PFPS group by 0.12 at 44 % of the jump cycle. SignificanceUsing simple functional GRF variables collected during functionally relevant task, in conjunction with FDboost, produced clinically interpretable models that retain excellent classification performance in individuals with PFPS. FDboost may be an invaluable tool to be used in longitudinal cohort prognostic studies, especially when scalar and functional predictors are collected.

Electromyographic activity of the quadriceps and gluteus medius muscles during/different straight leg raise and squat exercises in women with patellofemoral pain syndrome

Patellofemoral pain syndrome (PPS) is characterized by anterior knee pain and affects young female adults. Physiotherapy is the most indicated treatment. The objective of the study was to analyze electromyographic activity of the quadriceps and gluteus medius muscles during different open and closed kinetic chain exercises in women with PPS. Twenty-two clinically healthy women and 24 women with symptomatic PPS were assessed through surface electromyography of the quadriceps and gluteus medius during the following exercises: straight leg raise with and without lateral hip rotation; squats; squats with adduction and hip abduction; and squats combined with lateral hip rotation. When comparing the groups, only the quadriceps muscle showed higher activity in the PPS group. In the comparisons between the exercises, in relation to gluteus medius and quadriceps muscle activity, the straight leg raise and straight leg raise with lateral hip rotation exercises showed more activity than squats in both groups. Among the squats, squats with adduction generated more gluteus medius activity in both groups, and no difference was noted among the squats for the quadriceps muscle. Therefore, rehabilitation programs that include exercises such as straight leg raises, straight leg raises with lateral hip rotation, and squats with adduction may be used for PPS patients.

Geometry of Torsional Malalignment Syndrom: Trochlear Dysplasia but not Torsion Predicts Lateral Patellar Instability

Aims and Objectives: To analyze parameters of limb malalignment and patellar tracking in patients with torsional malalignment syndrome presenting with clinical symptoms of either patellofemoral pain or patellar instability. Materials and Methods: Between April 2015 and July 2017, 428 patients were treated for lateral patellar instability (LPD), and 333 patients were treated for patellofemoral pain syndrome (PFPS). Sixty-two patients (14.5%) with patellar instability (LPD group) and 29 patients (8.7%) with patellofemoral pain (PFPS group) had additional torsional malalignment and were included in this study. All patients underwent magnetic resonance imaging assessment of torsional alignment and patellar tracking, including femoral antetorsion, tibial torsion, knee rotation, tibial tuberosity-trochlear groove distance, tibial tuberosity-posterior cruciate ligament distance, Dejour’s classification of trochlear dysplasia, lateral trochlear inclination angle, and patellar height Results: Groups differed significantly in terms of trochlear dysplasia (p&lt;0.001), lateral trochlear inclination angle (p&lt;0.001) and tibial tuberosity-trochlear groove distance (p=0.0167) but did not differ in terms of femoral torsion (LPD group 20.02° +/- 8.8°; PFPS group 20.03° +/- 7.91°; p=0.8545), tibial torsion (LPD group 39.53° +/- 9.23°; PFPS group 41.24° +/- 7.28°; p=0.3616), and knee rotation (LPD group 10.42° +/- 5.16°; PFPS group 8.48° +/- 7.81°; p=0.0163). Only measures of coronal alignment were positively correlated. This was also true for the tibial tuberosity-trochlear groove distance and knee rotation but not for any other parameters of torsional limb alignment. Trochlear dysplasia (type B-D) was identified as the only significant predictor of patellar instability. Conclusion: Torsional malalignment syndrome, represented in this study by two clinical entities - PFPS and LPD - is not characterized by a typical constellation of different malalignment parameters. Between groups, parameters differed significantly only in terms of trochlear dysplasia and the tibial tuberosity-trochlear groove distance, with trochlear dysplasia (type B-D), but not torsion, identified as predictor of lateral patellar instability.

Backward walking alters vastus medialis oblique/vastus lateralis muscle activity ratio in females with patellofemoral pain syndrome.

This study aims to examine the effect of backward walking (BW) and forward walking (FW) on the myoelectric activity ratio of the vastus medialis oblique (VMO)/vastus lateralis (VL) in females with patellofemoral pain syndrome (PFPS). Between September 2016 and December 2016, a total of 40 female participants (mean age 20.9±1.9 years; range, 19 to 26 years) were included in the study. The participants were divided into two groups as those with unilateral PFPS (PFPS group, n=20) and healthy controls (Control group, n=20). Surface electromyography (EMG) from VMO and VL muscles were collected during FW and BW at a speed of 3 km/h using the Myomonitor® IV EMG system. There was a significant increase in the EMG activities of the VMO and VL muscles during BW compared to FW in PFPS and healthy groups (p=0.001). During BW, the VMO activity of PFPS was significantly higher than the healthy controls (p=0.013) without any significant difference in the VL activity (p=0.916). During FW, there was no significant difference in the VMO and VL activities between the groups (p=0.348 and p=0.705), respectively. The VMO/VL ratio of the PFPS group during BW was significantly higher than the FW ratio (p=0.001) without any significant difference between BW and FW of the healthy group (p=0.841). During BW, the ratio of the PFPS group was significantly higher than compared to the healthy controls (p=0.016) without any significant difference between the groups during FW (p=0.100). Our study results show that BW increases the VMO muscle activation and preserve the ideal VMO/VL ratio in PFPS patients. Therefore, clinicians should consider BW training when developing rehabilitation programs for females with PFPS.

Ultrasonographic assessment of quadriceps and patellar tendon thicknesses in patients with patellofemoral pain syndrome

ObjectiveThe aim of this study was to compare ultrasonographically measured quadriceps and patellar tendon thicknesses between Patellofemoral Pain Syndrome (PFPS) patients and age- and gender-matched healthy controls. MethodsAmong patients who presented to physical therapy and rehabilitation outpatient clinic in January–December 2016, 61 volunteers (28 men and 33 women; mean age: 30.79 ± 6.55 years) who were eligible considering the inclusion and exclusion criteria were enrolled. 30 were diagnosed with PFPS, and the remaining were age- and gender-matched healthy volunteers. Mean age was 30.03 ± 5.67 years in healthy subjects and 45.2% were of male gender. The patient group had mean age of 31.57 ± 7.37 years and 46.7% of the patients were male. Q angles were measured at standing, supine and sitting positions. Patellar and femoral tendon thicknesses and areas were measured ultrasonographically. Kujala questionnaire were used to evaluate the functional status of the participants. ResultsNo significant difference was detected between groups regarding profession, educational background, and body mass indices (BMI) (p > 0.05). Q angle values were significantly higher in the patient group when compared to controls at standing (17.03 ± 3.84 vs. 13.87 ± 1.75°, p < 0.001), supine (16.20 ± 3.74 vs. 13.45 ± 1.79°, p = 0.001) and sitting (16.50 ± 3.28 vs. 13.71 ± 1.72°, p < 0.001) positions. Kujala score was significantly lower in the PFPS group when compared to controls (70.57 ± 8.37 vs. 98.58 ± 2.05, p < 0.001). Patellar (0.39 ± 0.08 vs. 0.32 ± 0.05 cm, p < 0.001) and quadriceps (0.64 ± 0.10 vs. 0.52 ± 0.09 cm, p < 0.001) tendon thicknesses were significantly higher in the PFPS group when compared to controls. There was no significant difference between groups regarding patellar tendon areas (p > 0.05). Patellar tendon thickness values of ≥0.35 cm were found to have 66.7% sensitivity and 67.7% specificity for PFPS diagnosis in the ROC curve analysis (area under curve: 0.771, 95% confidence interval: 0.655–0.887, p < 0.001). Quadriceps tendon thickness values of ≥0.54 cm were found to have 80% sensitivity and 71% specificity for PFPS diagnosis in the ROC curve analysis (area under curve: 0.824, 95% confidence interval: 0.710–0.939, p < 0.001). In PFPS patients, quadriceps tendon thickness had significant positive correlation with age (r = 0.405, p = 0.027) and BMI (r = 0.450, p = 0.013); and significant negative correlation with Kujala score (r = −0.441, p = 0.015). In the multivariate regression analysis, quadriceps tendon thickness was independently associated with the presence of PFPS (Exp (B): 3.089, 95% confidence interval: 1.344–7.100, p = 0.008). ConclusionOur study demonstrates that ultrasonographically measured patellar and quadriceps tendon thicknesses are significantly higher in subjects with PFPS and particularly, quadriceps tendon thickness may be used for the diagnosis. Level of EvidenceLevel III, Therapeutic Study.

The effect of shear-wave elastography on functional results and muscle stiffness in patients undergoing non-selective and selective open kinetic chain exercises.

This study aims to assess the effect of shear-wave elastography (SWE) on vastus medialis obliquus (VMO) and vastus lateralis (VL) muscle performances and functional outcomes of patients with patellofemoral pain syndrome (PFPS) undergoing non-selective open kinetic chain exercises (NSOKCE) and selective open kinetic chain exercises (SOKCE). This randomized-controlled clinical trial included a total of 40 patients with PFPS (20 males, 20 females; mean age 46.5±9.8 years, range, 27 to 65 years) and 40 healthy controls (20 males, 20 females; mean age 36.3±11.2 years, range, 23 to 71) between February 2013 and August 2014. The participants in each group were randomized into subgroups according to NSOKCE or SOKCE for six weeks. The VMO and VL muscles were assessed with the SWE, thigh circumferences were measured, and the Visual Analog Scale (VAS) and Lysholm Knee Scale (LKS) scores were obtained. The OKCE alleviated pain, improved LKS scores, and increased the thigh circumference in PFPS patients. While the healthy controls were able to increase the resting muscle tone of their VMO, the patients with PFPS failed in their both knees. Similarly, resting as well as contracted VMO and VL muscles' functions were improved significantly by both NSOKCE and SOKCE in the healthy controls. The NSOKCE improved the VAS scores in the PFPS group. The increase in the muscle mass of the affected sides of PFPS patients were more evident with NSOKCE. Our study results show that NSOKCE planning can be preferred over SOKCE, thanks to its contribution to pain improvement and increase in the thigh circumference in the conservative treatment of PFPS.

Geometry of Torsional Malalignment Syndrome: Trochlear Dysplasia but Not Torsion Predicts Lateral Patellar Instability.

Background:The clinical impact of increased torsion on patellar instability and patellofemoral pain syndrome (PFPS) has been suggested by several studies.Hypothesis:The hypotheses of this study were that (1) torsional malalignment (TM) is characterized by a positive correlation between different malalignment parameters that represent an overall picture of the malalignment syndrome and (2) an increase in overall torsion is the underlying difference between patellar instability and isolated patellofemoral pain.Study Design:Cohort study; Level of evidence, 3.Methods:Between April 2015 and July 2017, a total of 428 patients were treated for lateral patellar dislocation (LPD), and 333 patients were treated for PFPS. Sixty-two patients (14.5%) with patellar instability (LPD group) and 29 patients (8.7%) with patellofemoral pain (PFPS group) had additional TM and were included in this study. All patients underwent magnetic resonance imaging for torsional alignment and patellar tracking, including femoral antetorsion, tibial torsion, knee rotation, tibial tuberosity–trochlear groove (TT-TG) distance, tibial tuberosity–posterior cruciate ligament (TT-PCL) distance, Dejour classification of trochlear dysplasia, lateral trochlear inclination (LTI) angle, and patellar height.Results:The LPD and PFPS groups differed significantly in terms of trochlear dysplasia (P < .001), LTI angle (P < .001), and TT-TG distance (P = .0167) but did not differ in terms of femoral antetorsion (20.02° ± 8.80° vs 20.03° ± 7.91°, respectively; P = .8545), tibial torsion (39.53° ± 9.23° vs 41.24° ± 7.28°, respectively; P = .3616), or knee rotation (10.42° ± 5.16° vs 8.48° ± 7.81°, respectively; P = .0163). Only measures of TT-TG distance and TT-PCL distance and measures of TT-TG distance and knee rotation were positively correlated. Trochlear dysplasia (type B-D) was identified as the only significant predictor of patellar instability.Conclusion:TM in patients with either PFPS or LPD does not appear to be characterized by a fixed constellation of different malalignment parameters. Between groups, the parameters differed significantly only in terms of trochlear dysplasia and the TT-TG distance, and trochlear dysplasia (type B-D) (but not torsion) was identified as a predictor of lateral patellar instability.

Frontal Plane Projection Angle during Step Down Test in Subjects With and Without Patellofemoral Pain Syndrome

AbstractBackground: Patellofemoral Pain (PFP) is considered one of the most common forms of knee pain. Increased frontal-plane knee motion during dynamic activities may play a role in the development of PFP due to alterations in joint loading at the patellofemoral joint and increased stress on the peri-articular structures of the patella.Aim of Study: To determine if there is an alteration of the frontal plane projection angle during step down test in subjects with and without Patellofemoral Pain Syndrome (PFPS).Subjects and Methods: Forty participants, with age be-tween 18-35 years, 20 PFPS and 20 healthy control group. FPPA angle for both groups was measured by digital video camera and was analyzed by kinovea software for motion analysis during performing Step down test.Results: There was no significant difference in the median value of FPPA between the affected side in the PFPS group and the healthy group (p=0.72).Conclusion: PFPS is not linked to altered FFPA during step down task, this finding suggests that assessment of lower extremity kinematics in clinical practice need 3-D motion analysis not only one plane assessment.

Backward walking effects on activation pattern of leg muscles in young females with patellofemoral pain syndrome

Background/Aims: Little is known regarding the activation of knee and hip muscles during backward walking in patellofemoral pain syndrome. This study examineD the effects of backward walking and forward walking on the activation of knee extensors, hip abductors, and adductors in patients with patellofemoral pain syndrome. Methods: A total of 20 females with patellofemoral pain syndrome and 20 age-matched typically healthy female controls participated in this study. Surface electromyography from vastus medialis obliquus, vastus lateralis, gluteus medius, and adductor longus muscles were collected during forward walking and backward walking. Findings: The patellofemoral pain syndrome group had a significantly higher normalised root mean square of the vastus medialis obliquus, vastus lateralis and gluteus medius muscles (P=0.001), without significant difference in adductor longus muscle activity during backward walking versus forward walking (P=0.098). During forward walking, the patellofemoral pain syndrome group showed significantly higher activation of adductor longus muscle (P=0.001) and significantly lower activation of the gluteus medius muscle (P=0.002) compared to the healthy group. During backward walking there was a significant increase in the vastus medialis obliquus and adductor longus muscle activity of the patellofemoral pain syndrome group compared to the control group (P=0.003, 0.001) respectively. Conclusions: Clinicians should consider backward walking training to increase the muscle strength of knee extensors and hip abductors when developing rehabilitation programmes for patients with patellofemoral pain syndrome.

Alterations in energy consumption and plantar pressure distribution during walking in young adults with patellofemoral pain syndrome

ObjectiveThe aim of this study was to determine the alterations of walking energy expenditure and plantar pressure distribution in young adults with patellofemoral pain syndrome (PFPS). MethodsThirty five individuals (mean age: 21.31 ± 1.76) with PFPS constituted the patient group and forty healthy participants (mean age: 21.40 ± 2.11) the control group. Preferred walking speeds (PWS) were determined on the over ground. Individuals walked on a treadmill for 7 min at their PWS and 30% above PWS and oxygen consumption was recorded via a metabolic analyzer. Net oxygen consumption was calculated for each walking trial. Borg scale was applied to assess perceived exertion during walking trial. Plantar pressure distributions were measured by a pedobarography device. Plantar area was subdivided into six zones to evaluate the dynamic plantar pressure data. ResultsThe mean PWS of PFPS and control groups were 4.69 ± 0.51 and 4.52 ± 0.60 km/h, respectively (p > .09). No significant difference was observed in energy expenditure during walking at PWS between 2 groups while oxygen consumption during 30% above PWS was higher in patient group (18.72 ± 3.75 and 16.64 ± 3.27) (p = .007). Net oxygen consumption was also found to be higher in PFPS group (15.12 ± 3.62 and 13.04 ± 3.24) (p = .005). The mean Borg scores were significantly higher in PFPS group at each walking trials (p < .001). No statistically significant difference was found between weight distribution (%) of symptomatic and nonsymptomatic extremity (50.45 ± 3.92% and 49.56 ± 3.93%, respectively) (p = .509). Dynamic pedobarography parameters were not different between 2 groups, and also between symptomatic and nonsymptomatic extremities (p > .05). ConclusionAlthough, rate of perceived exertion and energy expenditure during walking at 30% above PWS are affected negatively in young adults with PFPS, we may speculate that energy consumption and plantar pressure distribution can be compensated by a physiologic adaptation mechanism during walking at PWS. Level of evidenceLevel III, Therapeutic Study.