Are there three main subgroups within the patellofemoral pain population? A detailed characterisation study of 127 patients to help develop targeted intervention (TIPPs)

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.

A data mining approach for determining biomechanical adaptations in runners who experienced and recovered from patellofemoral pain syndrome

Patellofemoral pain (PFP) is a common musculoskeletal pain disorder experienced by runners. While biomechanics of those with PFP have been extensively studied, methodological considerations may omit important adaptations exhibited by those experiencing and recovered from pain. Instead of a priori selection of discrete biomechanical variables, a data mining approach was leveraged to account for the high dimensionality of running gait data. Biomechanical data of runners symptomatic for, recovered from, and who had never experienced PFP were collected at the 1st (M1) and 21st (M21) minutes of a treadmill run. Principal component analysis and a logistic regression model were used to classify healthy and symptomatic runners, and a feature ranking process determined the important features. The M1 model achieved an accuracy of 82.76% with features related to knee flexion angle, hip abduction moment and gluteus maximus activation, while the M21 model required an additional nine features to achieve an accuracy of 79.31%. Data for recovered runners were projected onto the models, resulting in five and seven out of twelve symptomatic classifications at M1 and M21, respectively. Following the onset of pain, a greater number of features were required to classify runners with PFP, suggesting they may experience individual pain adaptation strategies.

Quadriceps or hip exercises for patellofemoral pain? A randomised controlled equivalence trial

OBJECTIVE

To assess effectiveness equivalence between two commonly prescribed 12-week exercise programmes targeting either the quadriceps or the hip muscles in patients with patellofemoral pain (PFP).

METHODS

This randomised controlled equivalence trial included patients with a clinical diagnosis of PFP. Participants were randomly assigned to either a 12-week quadriceps-focused exercise (QE) or a hip-focused exercise (HE) programme. The primary outcome was the change in Anterior Knee Pain Scale (AKPS) (0-100) from baseline to 12-week follow-up. Prespecified equivalence margins of ±8 points on the AKPS were chosen to demonstrate comparable effectiveness. Key secondary outcomes were the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire pain, physical function and knee-related quality of life subscales.

RESULTS

200 participants underwent randomisation; 100 assigned to QE and 100 to HE (mean age 27.2 years (SD 6.4); 69% women). The least squares mean changes in AKPS (primary outcome) were 7.6 for QE and 7.0 for HE (difference 0.6 points, 95% CI -2.0 to 3.2; test for equivalence p<0.0001), although neither programme surpassed the minimal clinically important change threshold. None of the group differences in key secondary outcomes exceeded predefined equivalence margins.

CONCLUSION

The 12-week QE and HE protocols provided equivalent improvements in symptoms and function for patients with PFP.

TRIAL REGISTRATION NUMBER

NCT03069547.

Relationship between kinesiophobia, isometric hip and knee torques to pelvic, hip and knee motion during the single-leg drop jump in women with patellofemoral pain: A cross-sectional study

BACKGROUND

Individuals with patellofemoral pain (PFP) have kinesiophobia and hip and knee strength deficits. These factors may be related to kinematic alterations of pelvic, hip and knee during a more demanding functional activity, such as jumping landing. The aim was to investigate the relationships between kinesiophobia and hip/knee torque to pelvic/hip/knee kinematics during the single-leg drop vertical jump in women with PFP.

METHOD

Thirty women with PFP were assessed with Tampa Scale for Kinesiophobia; isokinetic dynamometry of the hip extensor, hip abductor, and knee extensor; and three-dimensional motion analysis system during the single-leg drop vertical jump. A Pearson correlation matrix was used to investigate relationship among variables.

RESULTS

Fair correlations were found between increased kinesiophobia and increased peak hip internal rotation angle (r = 0.43; p = 0.018) as well as between greater peak knee extensor torque and greater peak knee flexion (r = 0.41; p = 0.022). Moderate to good correlation was found between increased peak hip abductor torque and increased peak contralateral pelvic drop (r = 0.52; p = 0.003). No other significant correlations were found between variables.

CONCLUSIONS

Kinesiophobia is associated with hip kinematics, but not with knee kinematics, during the single-leg vertical drop jump in women with PFP. The greater hip abductor torque is associated with greater contralateral pelvic drop. The positive relationship between knee extensor torque and knee flexion indicates that rehabilitation programs involving quadriceps muscle strengthening may assist women with PFP in control knee flexion and improve load absorption during jumping landing.

Adding neuromuscular training to a strengthening program did not produce additional improvement in clinical or kinematic outcomes in women with patellofemoral pain: A blinded randomised controlled trial

BACKGROUND

Patellofemoral pain (PFP) is a knee pain condition with multifactorial aetiology, twice common in women. The recommended conservative treatment is based on strengthening of the core, hip, and knee musculatures. Addition of neuromuscular training to a strengthening protocol might provide further benefits on pain, function, and kinematics in PFP individuals. However, evidence for the effectiveness of this protocol is lacking.

OBJECTIVE

To investigate whether adding neuromuscular training to strengthening program could provide any additional improvements of pain, function, and kinematics in PFP women.

METHODS

71 PFP women were randomly into two groups and submitted to different interventions for 12 weeks. The strengthening group (SG) performed strengthening exercises for the trunk, hip, and knee muscles, while the neuromuscular training group (NMTG) performed the same exercises as SG, plus neuromuscular training from the 4th week onwards. The primary outcomes were pain intensity, function, and 2-D kinematics of the trunk and lower limb. The secondary outcomes were isometric muscle strength and patient satisfaction level. All outcomes were evaluated at 12 weeks, immediately post-treatment.

RESULTS

At 12 weeks, there was no evidence of between-group differences for any outcome, but both interventions provided clinically significant improvements for pain intensity (SG: mean difference -3.9, 95% confidence interval [CI] -5.0, -2.9; NMTG: mean difference -3.1, 95% CI -4.1, -2.0) and function (SG: mean difference 15.3, 95% CI 11.5, 19.2; NMTG: mean difference 16.9, 95% CI 13.2, 20.7).

CONCLUSION

Neuromuscular training did not produce any additional benefits for pain, function, or kinematics at 12 weeks of treatment.

Kinematic and Kinetic Gait Characteristics in People with Patellofemoral Pain: A Systematic Review and Meta-analysis

BACKGROUND

Patellofemoral pain (PFP) is a prevalent knee condition with many proposed biomechanically orientated etiological factors and treatments.

OBJECTIVE

We aimed to systematically review and synthesize the evidence for biomechanical variables (spatiotemporal, kinematic, kinetic) during walking and running in people with PFP compared with pain-free controls, and determine if biomechanical variables contribute to the development of PFP.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

We searched Medline, CINAHL, SPORTDiscus, Embase, and Web of Science from inception to October 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

All study designs (prospective, case-control [± interventional component, provided pre-intervention data were reported for both groups], cross-sectional) comparing spatiotemporal, kinematic, and/or kinetic variables during walking and/or running between people with and without PFP.

RESULTS

We identified 55 studies involving 1300 people with PFP and 1393 pain-free controls. Overall pooled analysis identified that people with PFP had slower gait velocity [moderate evidence, standardized mean difference (SMD) - 0.50, 95% confidence interval (CI) - 0.72, - 0.27], lower cadence (limited evidence, SMD - 0.43, 95% CI - 0.74, - 0.12), and shorter stride length (limited evidence, SMD - 0.46, 95% CI - 0.80, - 0.12). People with PFP also had greater peak contralateral pelvic drop (moderate evidence, SMD - 0.46, 95% CI - 0.90, - 0.03), smaller peak knee flexion angles (moderate evidence, SMD - 0.30, 95% CI - 0.52, - 0.08), and smaller peak knee extension moments (limited evidence, SMD - 0.41, 95% CI - 0.75, - 0.07) compared with controls. Females with PFP had greater peak hip flexion (moderate evidence, SMD 0.83, 95% CI 0.30, 1.36) and rearfoot eversion (limited evidence, SMD 0.59, 95% CI 0.03, 1.14) angles compared to pain-free females. No significant between-group differences were identified for all other biomechanical variables. Data pooling was not possible for prospective studies.

CONCLUSION

A limited number of biomechanical differences exist when comparing people with and without PFP, mostly characterized by small-to-moderate effect sizes. People with PFP ambulate slower, with lower cadence and a shortened stride length, greater contralateral pelvic drop, and lower knee flexion angles and knee extension moments. It is unclear whether these features are present prior to PFP onset or occur as pain-compensatory movement strategies given the lack of prospective data.

TRIAL REGISTRATION

PROSPERO # CRD42019080241.

Toward improved understanding of foot shape, foot posture, and foot biomechanics during running: A narrative review

The current narrative review has explored known associations between foot shape, foot posture, and foot conditions during running. The artificial intelligence was found to be a useful metric of foot posture but was less useful in developing and obese individuals. Care should be taken when using the foot posture index to associate pronation with injury risk, and the Achilles tendon and longitudinal arch angles are required to elucidate the risk. The statistical shape modeling (SSM) may derive learnt information from population-based inference and fill in missing data from personalized information. Bone shapes and tissue morphology have been associated with pathology, gender, age, and height and may develop rapid population-specific foot classifiers. Based on this review, future studies are suggested for 1) tracking the internal multi-segmental foot motion and mapping the biplanar 2D motion to 3D shape motion using the SSM; 2) implementing multivariate machine learning or convolutional neural network to address nonlinear correlations in foot mechanics with shape or posture; 3) standardizing wearable data for rapid prediction of instant mechanics, load accumulation, injury risks and adaptation in foot tissue and bones, and correlation with shapes; 4) analyzing dynamic shape and posture via marker-less and real-time techniques under real-life scenarios for precise evaluation of clinical foot conditions and performance-fit footwear development.

Six Treatments Have Positive Effects at 3 Months for People With Patellofemoral Pain: A Systematic Review With Meta-analysis

OBJECTIVE: To determine the effects of nonsurgical treatments on pain and function in people with patellofemoral pain (PFP). DESIGN: Systematic review with meta-analysis. LITERATURE SEARCH: We searched MEDLINE, Web of Science, and Scopus databases from their inception until May 2022 for interventional randomized controlled trials (RCTs) in people with PFP. STUDY SELECTION CRITERIA: We included RCTs that were scored ≥7 on the PEDro scale. DATA SYNTHESIS: We extracted homogenous pain and function data at short- (≤3 months), medium- (>3 to ≤12 months) and long-term (>12 months) follow-up. Interventions demonstrated primary efficacy if outcomes were superior to sham, placebo, or wait-and-see control. Interventions demonstrated secondary efficacy if outcomes were superior to an intervention with primary efficacy. RESULTS: We included 65 RCTs. Four interventions demonstrated short-term primary efficacy: knee-targeted exercise therapy for pain (standardized mean difference [SMD], 1.16; 95% CI: 0.66, 1.66) and function (SMD, 1.19; 95% CI: 0.51, 1.88), combined interventions for pain (SMD, 0.79; 95% CI: 0.26, 1.29) and function (SMD, 0.98; 95% CI: 0.47, 1.49), foot orthoses for global rating of change (OR = 4.31; 95% CI: 1.48, 12.56), and lower-quadrant manual therapy for function (SMD, 2.30; 95% CI: 1.60, 3.00). Two interventions demonstrated short-term secondary efficacy compared to knee-targeted exercise therapy: hip-and-knee-targeted exercise therapy for pain (SMD, 1.02; 95% CI: 0.58, 1.46) and function (SMD, 1.03; 95% CI: 0.61, 1.45), and knee-targeted exercise therapy and perineural dextrose injection for pain (SMD, 1.34; 95% CI: 0.72, 1.95) and function (SMD, 1.21; 95% CI: 0.60, 1.82). CONCLUSIONS: Six interventions had positive effects at 3 months for people with PFP, with no intervention adequately tested beyond this time point. J Orthop Sports Phys Ther 2022;52(11):750-768. Epub: 8 September 2022. doi:10.2519/jospt.2022.11359.

Prospective comparative study between knee alignment-oriented static and dynamic balance exercise in patellofemoral pain syndrome patients with dynamic knee valgus

Exercise therapy has been reported as an effective treatment method for patellofemoral pain syndrome (PFPS). However, there is a lack of studies regarding the effectiveness of balance exercise in the treatment of patients with PFPS. This study aimed to prospectively compare changes in proprioception, neuromuscular control, knee muscle strength, and patient-reported outcomes between patients with PFPS treated with knee alignment-oriented static balance exercise (SBE) and dynamic balance exercise (DBE). The participants were divided into 2 groups: 17 knee alignment-oriented SBE group and 19 knee alignment-oriented DBE group. Proprioception was assessed by dynamic postural stability using postural stabilometry. Neuromuscular control and knee muscle strength were measured for acceleration time and peak torque in quadriceps muscle using an isokinetic device. Patient-reported outcomes were evaluated using a visual analog scale for pain and the Kujala Anterior Knee Pain Scale. There was greater improvement in dynamic postural stability (0.9 ± 0.3 vs 1.2 ± 0.5; 95% confidence interval [CI]: 0, 0.6; Effect size: 0.72; P = .021) and quadriceps AT (40.5 ± 14.3 vs 54.1 ± 16.9; 95% CI: 2.9, 24.2; Effect size: 0.86; P = .014) in the DBE group compared to the SBE group. Knee alignment-oriented DBE can be more effective in improving dynamic postural stability and quadriceps muscle reaction time compared with the knee alignment-oriented SBE in PFPS patients with dynamic knee valgus.

Reduced Vastus Medialis/Lateralis EMG Ratio in Volleyballers with Chronic Knee Pain on Sports-Specific Surfaces: A Pilot Study

BACKGROUND

Even though chronic knee pain is common in volleyball, neuromuscular imbalance as a potential risk factor has not been investigated in volleyball-specific tasks. The aim of the study was to compare neuromuscular control between healthy and injured players in a clinical jump test and a volleyball-specific jump task in real field conditions.

METHODS

Six athletes with knee pain and nine controls were included. Surface electromyographic data were recorded from the mm. vastus medialis (VM) and lateralis (VL) of both legs. VM/VL activation ratio was calculated from countermovement jump (CMJ) and volleyball spike indoors and on two beach surfaces.

RESULTS

All subjects had pain in the leading leg. Mann-Whitney U Test (M-W-U Test) revealed a significantly lower VM/VL ratio of the leading leg (always affected) of the injured compared with that of the healthy control group for the CMJ and spike jump on all three grounds. Bland-Altman analysis revealed low bias and low difference in standard deviation for the injured leg but high values for the uninvolved leg and healthy controls between tasks and grounds. These results could indicate that neuromuscular control might not adapt too well to different movement tasks and grounds in the injured leg.

CONCLUSION

Athletes with chronic knee pain might have lower VM/VL ratios than controls independent from movement task and ground. Neuromuscular control in injured athletes might be less adaptable to new circumstances. The results of neuromuscular control in laboratory settings might be applicable to field conditions in injured legs but not healthy ones.

The efficacy of a tart cherry drink for the treatment of patellofemoral pain in recreationally active individuals: a placebo randomized control trial

Purpose

This study aimed to explore the efficacy of U.S. Montmorency tart cherry in treating recreationally active individuals with patellofemoral pain.

Methods

Twenty-four recreationally active participants with patellofemoral pain were randomly separated into either placebo (males N = 8, females N = 4, age = 43.30 ± 7.86 yrs, mass = 72.10 ± 17.89 kg, stature = 171.16 ± 10.17, BMI = 24.31 ± 3.75 kg/m2, symptom duration = 30.18 ± 10.90) or Montmorency tart cherry (males N = 9, females N = 3, age = 41.75 ± 7.52 yrs, mass = 76.96 ± 16.64 kg, stature = 173.05 ± 7.63, BMI = 25.53 ± 4.03 kg/m2, symptom duration = 29.73 ± 11.88) groups. Both groups ingested 60 mL of either Montmorency tart cherry concentrate or taste matched placebo daily for 6 weeks. Measures of self-reported pain (KOOS-PF), psychological wellbeing (COOP WONCA), and sleep quality (PSQI) alongside blood biomarkers (C-reactive protein, uric acid, TNF alpha, creatinine, and total antioxidant capacity) and knee biomechanics were quantified at baseline and 6 weeks. Differences between groups were examined using linear mixed-effects models.

Results

There was 1 withdrawal in the cherry and 0 in the placebo group and no adverse events were noted in either condition. The placebo condition exhibited significant improvements (baseline = 67.90 ± 16.18 & 6 weeks = 78.04 ± 14.83) in KOOS-PF scores compared to the tart cherry group (baseline = 67.28 ± 12.55& 6 weeks = 67.55 ± 20.61). No other statistically significant observations were observed.

Conclusion

Tart cherry supplementation as specifically ingested in the current investigation does not appear to be effective in mediating improvements in patellofemoral pain symptoms in recreationally active individuals.

Short foot exercises have additional effects on knee pain, foot biomechanics, and lower extremity muscle strength in patients with patellofemoral pain

BACKGROUND

Patellofemoral pain (PFP) is a common knee problem. The foot posture in a relaxed stance is reported as a distal factor of PFP. However, the effects of short foot exercise (SFE) on the knee and functional factors have not yet been investigated in patients with PFP.

OBJECTIVE

This study aimed to investigate the additional effects of SFE on knee pain, foot biomechanics, and lower extremity muscle strength in patients with PFP following a standard exercise program.

METHODS

Thirty patients with a 'weak and pronated' foot subgroup of PFP were randomized into a control group (ConG, n= 15) and a short foot exercise group (SFEG, n= 15) with concealed allocation and blinded to the group assignment. The program of ConG consisted of hip and knee strengthening and stretching exercises. SFEG program consisted of additional SFE. Both groups performed the supervised training protocol two times per week for 6 weeks. Assessment measures were pain visual analog scale (pVAS), Kujala Patellofemoral Score (KPS), navicular drop test (NDT), rearfoot angle (RA), foot posture index (FPI), and strength tests of the lower extremity muscles.

RESULTS

Both groups displayed decreases in pVAS scores, but it was only significant in favor of SFEG. NDT, RA, and FPI scores decreased in SFEG whereas they increased in ConG. There was a significant group-by-time interaction effect in hip extensor strength and between-group difference was found to be significantly in favor of SFEG.

CONCLUSIONS

An intervention program consisting of additional SFE had positive effects on knee pain, navicular position, and rearfoot posture. An increase in the strength of the hip extensors may also be associated with improved stabilization by SFE.

IMMEDIATE EFFECTS OF SEMI-CUSTOM INSOLES AND STRUCTURED KNEE SLEEVES ON LOWER EXTREMITY KINETICS AND KINEMATICS IN RECREATIONAL MALE ATHLETES WITH PATELLOFEMORAL PAIN

The aim of this experiment was to provide insight into the immediate influence of both semi-custom insoles and knee sleeves in recreational male runners/athletes suffering from patellofemoral pain and also to explore the association between the extent of patellofemoral pain and psychological wellbeing. Experiment 1 examined 17 male recreational runners with patellofemoral pain, in semi-custom insole and no-insole conditions. Experiment 2 examined 13 male recreational athletes with patellofemoral pain, undertaking run, [Formula: see text] cut and single-leg hop movements in knee sleeve and no-sleeve conditions. In both experiments, motion capture and ground reaction forces were collected, allowing kinetics and three-dimensional kinematics to be calculated alongside patellofemoral joint loading quantified using musculoskeletal modeling. In both experiments, patellofemoral pain symptoms were examined using the KOOS patellofemoral pain subscale and psychological wellbeing using the COOP-WONCA questionnaire. The findings from both experiments showed that pain symptoms significantly predicted psychological wellbeing ([Formula: see text] in experiment 1 and [Formula: see text] in experiment 2). Experiment 1 showed that orthoses significantly reduced tibial internal rotation range of motion (no-[Formula: see text] and [Formula: see text]) whilst also increasing the peak knee adduction moment (no-[Formula: see text][Formula: see text]N[Formula: see text]m/kg and [Formula: see text][Formula: see text]N[Formula: see text]m/kg). The findings from experiment 2 revealed that the knee sleeve reduced the peak patellofemoral force (no-[Formula: see text][Formula: see text]BW and [Formula: see text][Formula: see text]BW) in the run movement and the patellofemoral load rate in the cut movement (no-[Formula: see text][Formula: see text]BW/s and [Formula: see text][Formula: see text]BW/s). Overall, the findings confirm that pain symptoms are predictive of psychological wellbeing in recreational male athletes with patellofemoral pain. Furthermore, the findings suggest that both insoles and knee sleeves may provide immediate biomechanical benefits in recreationally active individuals with patellofemoral pain, although when wearing insoles this may be at the expense of an increased knee adduction moment during running.

Patellofemoral kinematics in patellofemoral pain syndrome: The influence of demographic factors

Due to the multifactorial nature of patellofemoral pain, it is often difficult to identify an individual patient's exact cause of pain. Understanding how demographic variability influences these various factors will support improved consensus in regards to the etiology of PF pain. Thus, in this retrospective study, we tested the hypothesis that sex, height, weight, body mass index (BMI), and age influence the determination of between-groups differences in PF kinematics. We included 41 skeletally mature patients with patellofemoral pain and 79 healthy controls. Three-dimensional patellofemoral kinematics were quantified from dynamic magnet resonance images. We ran multiple regression analyses to determine the influence of demographic covariates (age, sex, height, weight, and BMI) on patellofemoral kinematics. Patellar shift was significantly influenced by weight (p = 0.009) and BMI (p = 0.009). Patellar flexion was influenced by height (p = 0.020) and weight (p = 0.040). Patellar tilt and superior displacement were not influence by demographic variables. Age and sex did not influence kinematics. This study supports the hypothesis that demographic parameters influence PF kinematics. The fact that weight, a modifiable measure, influences both patellar shift and flexion has strong implications for future research and clinical interventions. Clinically, weight loss may have a dual benefit of reducing joint stress and maltracking in patients who are overweight and experiencing patellofemoral pain. The influence of key demographics on patellofemoral kinematics, reinforces the clear need to control for population characteristics in future studies. As such, going forward, improved demographic matching between control and patient cohorts or more advanced statistical techniques that compensate for confounding variables are necessary.

An exploration of normative values in New Zealand to inform the Targeted Interventions for Patellofemoral Pain approach

BACKGROUND

The Targeted Interventions for Patellofemoral Pain studies (TIPPs) have identified three subgroups exist in United Kingdom and Turkish patellofemoral pain (PFP) populations: Strong; Weak and Tight; and Weak and Pronated, based on six clinical assessments. The thresholds used to develop the subgrouping algorithms were based on normative values sourced from various populations and countries.

OBJECTIVES

Explore normative scores from the clinical assessments in a singular non-PFP population whilst considering potential differences between ethnicities and sex (primary aim). Revisit inter-rater reliability of each assessment (secondary aim).

DESIGN

Cross-sectional and test-retest.

METHOD

The six assessments; rectus femoris length, gastrocnemius length, patellar mobility, hip abductor strength, quadriceps strength, and Foot Posture index (FPI) were measured in 89 New Zealanders (34% Māori, 45% female). Two raters independently assessed 17 participants to examine inter-rater reliability.

RESULTS

Significant interactions between ethnic group and sex were noted for rectus femoris length and patella mobility. Māori versus European males exhibited greater rectus femoris tightness (p = 0.001). Māori versus European females demonstrated greater patellar mobility (p = 0.002). Females were significantly weaker than males in normalised strength measures (p < 0.001), and had lower FPIs. Mean differences between testers for all measures were small and not significant, except for FPI which had a 2.0 point median difference (p = 0.021).

CONCLUSIONS

Our results indicate that sex is an important factor worth considering within the TIPPs subgrouping approach, more than ethnicity, especially for the normalised strength measures. The sub-optimal reliability of FPI warrant reconsideration of its inclusion within TIPPs.

How effective is an evidence-based exercise intervention in individuals with patellofemoral pain?

OBJECTIVES

Guidelines for a comprehensive rehabilitation programme for patellofemoral pain (PFP) have been developed by international experts. The aim of this study was to analyse the effect of such a rehabilitative exercise programme on pain, function, kinesiophobia, running biomechanics, quadriceps strength and quadriceps muscle inhibition in individuals with PFP.

DESIGN

Observational study.

SETTING

Clinical environment.

PARTICIPANTS

Twenty-seven participants with PFP.

MAIN OUTCOME MEASURES

Symptoms [numeric pain rating scale (NPRS)and the pain subscale of the Knee Injury and Osteoarthritis Outcome Score (KOOS)], function measured by using the KUJALA scale and KOOS, kinesiophobia measured by using the Tampa scale, three-dimensional biomechanical running data, quadriceps isometric, concentric and eccentric strength and arthrogenic muscle inhibition (AMI) were acquired before and after the six-week exercise programme.

RESULTS

Although pain did not significantly improve all patients were pain-free after the six-week exercise programme (NPRS: p = 0.074). Function, kinesiophobia and quadriceps AMI improved significantly after the six-week exercise programme (KUJALA: p = 0.001, KOOS: p = 0.0001, Tampa: p = 0.017, AMI: p = 0.018). Running biomechanics during stance phase did not change after the exercise intervention. Quadriceps strength was not different after the six-week exercise programme (isometric: p = 0.992, concentric: p = 0.075, eccentric: p = 0.351).

CONCLUSION

The results of this study demonstrate that the current exercise recommendations can improve function and kinesiophobia and reduce pain and AMI in individuals with PFP. There is a need for reconsideration of the current exercise guidelines in stronger individuals with PFP.

A Word of Caution for Future Studies in Patellofemoral Pain: A Systematic Review With Meta-analysis

BACKGROUND

Patellar maltracking is widely accepted as an underlying mechanism of patellofemoral pain. However, methodological differences in the literature hinder our ability to generate a universal quantitative definition of pathological patellofemoral kinematics (patellar maltracking) in patellofemoral pain, leaving us unable to determine the cause of patellofemoral pain.

PURPOSE

To systematically review the literature to provide evidence regarding the influence of confounding variables on patellofemoral kinematics.

STUDY DESIGN

Systematic review and random effects meta-analysis of control-case studies.

METHODS

A literature search of case-control studies that evaluated patellofemoral kinematics at or near full extension and were written in English was conducted using Embase, PubMed, Scopus, and Web of Science up to September 2019. Cases were defined as patients with patellofemoral pain. Studies were eliminated if they lacked quantitative findings; had a primary aim to assess therapy efficacy; or included participants with osteoarthritis and/or previous trauma, pathology, or surgery. A quality assessment checklist was employed to evaluate each study. Meta-analyses were conducted to determine the influence of confounding variables on measures of patellofemoral kinematics.

RESULTS

Forty studies met the selection criteria, with quality scores ranging from 13% to 81%. Patient characteristics, data acquisition, and measurement methods were the primary sources of methodological variability. Active quadriceps significantly increased lateral shift (standardized mean difference [SMD]_shift = 0.33; P = .0102) and lateral tilt (SMD_tilt = 0.43; P = .006) maltracking. Individuals with pain secondary to dislocation had greater effect sizes for lateral maltracking than had those with isolated patellofemoral pain (ΔSMD_shift = 0.71, P = .0071; ΔSMD_tilt = 1.38, P = .0055).

CONCLUSION

This review exposed large methodological variability across the literature, which not only hinders the generalization of results, but ultimately mitigates our understanding of the underlying mechanism of patellofemoral pain. Although our meta-analyses support the diagnostic value of maltracking in patellofemoral pain, the numerous distinct methods for measuring maltracking and the limited control for cofounding variables across the literature prohibit defining a single quantitative profile. Compliance with specific standards for anatomic and outcome measures must be addressed by the scientific and clinical community to establish methodological uniformity in this field.

Correlation of pain sensitization with muscle strength and angular kinematics in women with patellofemoral pain

BACKGROUND

Patellofemoral pain has a poor long-term prognosis, which can be explained by a pain sensitization process. The pain sensitization process may be related to the increase of stress in the patellofemoral joint that is already associated with kinematic alterations and weakness in the musculature of the hip and knee.

METHODS

Were compared the pressure pain threshold, temporal summation, conditioned pain modulation, angular kinematics, and muscle strength between 26 patellofemoral pain and 24 asymptomatic women and then correlated pain sensitization variables with biomechanical variables in pain group. The pressure pain threshold was determined on seven points of the knee, tibialis anterior muscle, and elbow. Ten consecutive stimuli were performed for temporal summation, and cold water was used as the conditioning stimulus for conditioned pain modulation. The strength of hip and knee muscles was determined using a manual dynamometer. Three-dimensional kinematics were evaluated during the lateral step down, considering peak and excursion values of the movement and the Movement Deviation Profile.

FINDINGS

The pressure pain threshold of the elbow (2.13 [1.84-2.41] vs. 1.63 [1.25-2] kg/cm²), all sites of the knee were lower, as well as the Movement Deviation Profile was higher (9.33 [9.20-9.46] vs. 12.43 [12.1-12.75]) in the pain group. No difference in temporal summation, conditioned pain modulation, muscle strength and discrete kinematic values were found. No significant correlation was found between the Movement Deviation Profile and pressure pain threshold.

INTERPRETATION

Biomechanical factors, pain processing, and modulation in women with patellofemoral pain, when different from asymptomatic individuals, are not necessarily associated.

Patellofemoral alignment, morphology and structural features are not related to sitting pain in individuals with patellofemoral pain

BACKGROUND

Sitting-related pain is a common feature of patellofemoral pain (PFP). However, little is known regarding features associated with sitting-related PFP. The aim of this study was to determine whether sitting-related PFP is associated with patellofemoral alignment, morphology and structural magnetic resonance imaging (MRI) features of the patellofemoral joint (cartilage lesions, bone marrow lesions, fat pad synovitis).

METHODS

133 individuals with PFP were included from two unique but similar cohorts. Participants were classified into one of three groups based on their response to item 8 of the Anterior Knee Pain Scale: (i) problems with sitting; (ii) sitting pain after exercise; and (iii) no difficulty with sitting. All participants underwent 3T Magnetic Resonance Imaging (MRI) to enable: (i) scoring of structural features of the patellofemoral joint with MRI Osteoarthritis Knee Score (MOAKS); and (ii) patellofemoral alignment and morphology measurements using standardised methods. The association of sitting pain to bony alignment, morphology and MOAKS features were evaluated using multinomial logistic regression (adjusted for age, sex, BMI; reference group = no difficulty with sitting).

RESULTS

82 (61.7%) participants reported problems with sitting, and 24 (18%) participants reported sitting pain after exercise. There were no significant associations between the presence of sitting pain and any morphology, alignment or structural characteristics.

CONCLUSIONS

Findings indicate that PFP related to sitting is not associated with patellofemoral alignment, morphology, or structural MRI features of the patellofemoral joint. Further research to determine mechanisms of sitting-related PFP, and inform targeted treatments, are required.

Short-term effectiveness of an intervention targeting lower limb range of motion on pain and disability in patellofemoral pain patients: A randomized, non-concurrent multiple-baseline study

INTRODUCTION

Patellofemoral pain (PFP) is a common and often long-standing musculoskeletal condition. Evidence of the effectiveness of interventions addressing soft tissue flexibility is conflicting and of inconsistent scientific quality. However, reduced soft tissue flexibility can negatively affect patellofemoral joint kinematics. Lower limb range of motion (LLROM) reflects soft tissue flexibility throughout the kinetic chain. The aim was to evaluate the short-term effectiveness of an intervention targeting LLROM on pain and disability in patients with PFP.

METHODS

A randomized, non-concurrent, multiple-baseline single-case design with a two-week intervention phase and baseline and postintervention phase with varying length was conducted. Eight participants (5 females, 3 males) of age 19(±1.6) years, weekly sports participation 12(±3.1) hours and 17(±14) months symptom duration were included. The Anterior Knee Pain Scale - Dutch Version (AKPS-DV) and the Patient Specific Complaint Scale (PSCS) were administered twice a week. After allocating participants to one of four subgroups of reduced LLROM the intervention was applied. The intervention consisted of soft tissue techniques (mobilization, taping, and stretching).

RESULTS

Participant 3 and 6 showed a medium and small but statistically significant positive effect on the AKPS-DV. Participant 2 showed a large and statistically significant positive effect on the PSCS.

CONCLUSIONS

This study provides moderate evidence that an intervention targeting LLROM in patients with PFP reduces pain and disability in the short-term. Further research is needed to evaluate the long-term effectiveness and optimize individual treatment outcomes.

A New Clustering Method for Knee Movement Impairments using Partitioning Around Medoids Model

Background:

The movement system impairment (MSI) model is a clinical model that can be used for the classification, diagnosis, and treatment of knee impairments. By using the partitioning around medoids (PAM) clustering method, patients can be easily clustered in homogeneous groups through the determination of the most discriminative variables. The present study aimed to reduce the number of clinical examination variables, determine the important variables, and simplify the MSI model using the PAM clustering method.

Methods:

The present cross-sectional study was performed in Shiraz, Iran, during February-December 2018. A total of 209 patients with knee pain were recruited. Patients’ knee, femoral and tibial movement impairments, and the perceived pain level were examined in quiet standing, sitting, walking, partial squatting, single-leg stance (both sides), sit-to-stand transfer, and stair ambulation. The tests were repeated after correction for impairments. Both the pain pattern and the types of impairment were subsequently used in the PAM clustering analysis.

Results:

PAM clustering analysis categorized the patients in two main clusters (valgus and non-valgus) based on the presence or absence of valgus impairment. Secondary analysis of the valgus cluster identified two sub-clusters based on the presence of hypomobility. Analysis of the non-valgus cluster showed four sub-clusters with different characteristics. PAM clustering organized important variables in each analysis and showed that only 23 out of the 41 variables were essential in the sub-clustering of patients with knee pain.

Conclusion:

A new direct knee examination method is introduced for the organization of important discriminative tests, which requires fewer clinical examination variables.

The effects of McConnell patellofemoral joint and tibial internal rotation limitation taping techniques in people with Patellofemoral pain syndrome

BACKGROUND

Taping is frequently used as part of the multi-modal management for patellofemoral pain syndrome (PFPS). McConnell Patellofemoral Joint Taping (PFJT) and Tibial Internal Rotation Limitation Taping (TIRLT) are proposed to be useful adjuncts to the management of PFPS. However, it is unclear if TIRLT offers similar benefits to PFJT, and its effect on pain and lower limb kinematics have not been investigated previously.

RESEARCH QUESTION

What are the effects of TIRLT, PFJT and no taping on perceived pain and lower limb kinematics during a lunge and single leg squat (SLS) in people with PFPS?

METHODS

This cross-sectional study compared the effects of TIRLT, PFJT and no taping, on knee pain and lower limb kinematics during two pain-provoking movements in people with PFPS. Participants with PFPS (n = 23) performed a lunge and SLS under three randomised conditions: TIRLT, PFJT and no taping. The Codamotion system captured and analysed lower limb kinematic data in the sagittal, transverse and coronal planes. Peak knee pain intensity during the movement was assessed using the Numerical Rating Scale (NRS).

RESULTS

Participants reported significantly less pain with the TIRLT and PFJT techniques compared with no tape during the lunge (p = 0.005 and p = 0.011, respectively) and SLS (p= 0.002 and p = 0.001, respectively). There was no evidence of altered lower limb kinematics accompanying pain reductions with either taping technique.

SIGNIFICANCE

Both forms of taping may be useful adjuncts as the short-term benefit of pain relief may enable participation in more active forms of rehabilitation.

Hot and cold knees: exploring differences in patella skin temperature in patients with patellofemoral pain

OBJECTIVES

To investigate the distribution of patella skin temperature (Tsk) measurements and to explore the presence of temperature subgroups in patellofemoral pain (PFP) patients.

DESIGN

Cross-sectional observational study design.

PARTICIPANTS

One dataset of 58 healthy participants and 232 PFP patients from three different datasets.

MAIN OUTCOME MEASURES

Patella skin temperature, measured by physiotherapists using a low cost hand held digital thermometer. The distribution of patella skin temperature was assessed and compared across datasets. To objectively determine the clinically meaningful number of subgroups, we used the average silhouette method. Finite mixture models were then used to examine the presence of PFP temperature subgroups. Receiver operating characteristic curves were used to estimate optimal patella Tsk thresholds for allocation of participants into the identified subgroups.

RESULTS

In contrast to healthy participants, the patella skin temperature had an obvious bimodal distribution with wide dispersion present across all three PFP datasets. The fitted finite mixture model suggested three temperature subgroups (cold, normal and hot) that had been recommended by the average silhouette method with discrimination cut-off thresholds for subgroup membership based on receiver operating curve analysis of Cold=<30.0°C; Normal 30.0-35.2°C; Hot ≥35.2°C.

CONCLUSION

A low cost hand held digital thermometer appears to be a useful clinical tool to identify three PFP temperature subgroups. Further research is recommended to deepen understanding of these clinical findings and to explore the implications to different treatments.

Mulligan Knee Taping Using Both Elastic and Rigid Tape Reduces Pain and Alters Lower Limb Biomechanics in Female Patients With Patellofemoral Pain

Background:

Evidence supports the use of Mulligan knee taping in managing patellofemoral pain (PFP). However, no studies have compared the efficacy of rigid and elastic tape using this technique.

Hypothesis:

Mulligan knee taping applied with both rigid and elastic tape will produce similar reductions in knee pain, hip internal rotation, and knee flexion moments compared with no tape. Elastic tape will also be more comfortable than rigid tape.

Study Design:

Controlled laboratory study.

Methods:

A total of 19 female patients (mean age, 26.5 ± 4.5 years) with PFP performed a self-selected pain provocative task, single-leg squat (SLSq) task, and running task while wearing Mulligan knee taping applied with rigid tape, elastic tape at 100% tension, and no tape. Pain and taping comfort were recorded using 11-point numeric rating scales. An 18-camera motion capture system and in-ground force plates recorded 3-dimensional lower limb kinematics and kinetics for the SLSq and running tasks. Statistical analysis involved a series of repeated-measures analyses of variance. The Wilcoxon signed rank test was used for analyzing taping comfort.

Results:

Compared with no tape, both rigid and elastic tape significantly reduced pain during the pain provocative task (mean difference [MD], –0.97 [95% CI, –1.57 to –0.38] and –1.42 [95% CI, –2.20 to –0.64], respectively), SLSq (MD, –1.26 [95% CI, –2.23 to –0.30] and –1.13 [95% CI, –2.09 to –0.17], respectively), and running tasks (MD, –1.24 [95% CI, –2.11 to –0.37] and –1.16 [95% CI, –1.86 to –0.46], respectively). Elastic tape was significantly more comfortable than rigid tape generally (P = .005) and during activity (P = .022). Compared with no tape, both rigid and elastic tape produced increased knee internal rotation at initial contact during the running task (MD, 5.5° [95% CI, 3.6° to 7.4°] and 5.9° [95% CI, 3.9° to 7.9°], respectively) and at the commencement of knee flexion during the SLSq task (MD, 5.8° [95% CI, 4.5° to 7.0°] and 5.8° [95% CI, 4.1° to 7.4°], respectively), greater peak knee internal rotation during the running (MD, 1.8° [95% CI, 0.4° to 3.3°] and 2.2° [95% CI, 0.9° to 3.6°], respectively) and SLSq tasks (MD, 3.2° [95% CI, 2.1° to 4.3°] and 3.8° [95% CI, 2.3° to 5.2°], respectively), and decreased knee internal rotation range of motion during the running (MD, –3.6° [95% CI, –6.1° to –1.1°] and –3.7° [95% CI, –6.2° to –1.2°], respectively) and SLSq tasks (MD, –2.5° [95% CI, –3.9° to –1.2°] and –2.0° [95% CI, –3.2° to –0.9°], respectively).

Conclusion:

Mulligan knee taping with both rigid and elastic tape reduced pain across all 3 tasks and altered tibiofemoral rotation during the SLSq and running tasks.

Clinical Relevance:

Both taping methods reduced pain and altered lower limb biomechanics. Elastic tape may be chosen clinically for comfort reasons.

The effect of match fatigue in elite badminton players using plantar pressure measurements and the implications to injury mechanisms

The purpose of this study was to investigate the differences in plantar pressure under the lead and trail foot between two lunge tasks to the net in the dominant (LD) and non-dominant (LND) directions, and to explore how fatigue affects the plantar pressure patterns whilst performing movements before and after a competitive match. Peak and mean pressure were measured with the Biofoot-IBV in-shoe system from five repetitions of each task, with sensors positioned under the calcaneus, midfoot and phalanges on the lead and trail foot. Data were collected pre and immediately post-playing an official first national league competition match. The study was conducted with a sample of thirteen first league badminton players. A 2 × 2 repeated ANOVA found significant differences between the two tasks and between pre- and post-match (fatigued state). Players also had different foot pressure distributions for the LD and LND tasks, which indicated a difference in loading strategy. In a fatigued state, the plantar pressure shifted to the medial aspect of the midfoot in the trail limb, indicating a reduction in control and a higher injury risk during non-dominant lunge tasks.

Does foot mobility affect the outcome in the management of patellofemoral pain with foot orthoses versus hip exercises? A randomised clinical trial

Objectives

To test (i) if greater foot pronation (measured as midfoot width mobility) is associated with better outcomes with foot orthoses treatment, compared with hip exercises and (ii) if hip exercises are superior to foot orthoses, irrespective of midfoot width mobility.

Methods

A two-arm parallel, randomised superiority clinical trial was conducted in Australia and Denmark. Participants (18–40 years) were included who reported an insidious onset of knee pain (≥6 weeks duration); ≥3/10 numerical pain rating, that was aggravated by activities (eg, stairs, squatting, running). Participants were stratified by midfoot width mobility (high ≥11 mm change in midfoot width) and site, randomised to foot orthoses or hip exercises and blinded to objectives and stratification. Success was defined a priori as much better or better on a patient-perceived 7-point scale at 12 weeks.

Results

Of 218 stratified and randomised participants, 192 completed 12-week follow-up. This study found no difference in success rates between foot orthoses versus hip exercises in those with high (6/21 vs 9/20; 29% vs 45%, respectively) or low (42/79 vs 37/72; 53% vs 51%) midfoot width mobility. There was no association between midfoot width mobility and treatment outcome (Interaction effect p=0.19). This study found no difference in success rate between foot orthoses versus hip exercises (48/100 vs 46/92; 48% vs 50%).

Conclusion

Midfoot width mobility should not be used to help clinicians decide which patient with patellofemoral pain might benefit most from foot orthoses. Clinicians and patients may consider either foot orthoses or hip exercises in managing patellofemoral pain.

Trial registration number

ACTRN12614000260628.

An exploration of the differences in hip strength, gluteus medius activity, and trunk, pelvis, and lower-limb biomechanics during different functional tasks

The purpose of the study was to explore differences in the coronal biomechanics of the trunk, pelvis, hip, and knee joints, and gluteus medius muscle activity (GMed) during walking and step down from two riser heights. Joint kinematics and kinetics from 20 healthy participants were recorded using a 10-camera Qualisys system and force plates, and GMed EMG was recorded using a Delsys Trigno system. Hip abductor strength was measured using a hand-held dynamometer. Pelvic obliquity and lateral trunk bending excursions were significantly higher in walking than in step-down tasks. Significantly greater knee adduction moments were seen during both step-down tasks compared to level walking with significantly greater GMed activity. However, a significant interaction between side and task was seen for hip adduction moment, with step-down tasks showing lower hip moments than during walking, with greater peak hip moments being more apparent in the dominant limb. This suggests the GMed has a greater stabilizing role during the step-down tasks, although walking required a greater mechanical demand. Health professionals should expect to find less excursion of lateral trunk bending in step-down tasks compared to level walking and consider that GMed has different roles in these two tasks.

Patellofemoral Pain in Adolescents: Understanding Patellofemoral Morphology and Its Relationship to Maltracking

BACKGROUND

Developing bone is highly adaptable and, as such, is susceptible to pathological shape deformation. Thus, it is imperative to quantify if changes in patellofemoral morphology are associated with adolescent-onset patellofemoral pain, as a pathway to improve our understanding of this pain's etiology.

PURPOSE

To quantify and compare patellofemoral morphology in adolescent patients with patellofemoral pain with matched healthy adolescent controls and determine if a relationship exists between patellofemoral shape and kinematics (measured during active flexion-extension).

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Using 3-dimensional static magnetic resonance images acquired during a previous study, we measured patellar, trochlear, and lateral patellar width; trochlear and patellar depth; Wiberg index; patellar-height ratio; lateral trochlear inclination; cartilage length; and lateral femoral shaft length. Student t test was used to compare shape parameters between adolescents with patellofemoral pain and controls. Pearson correlations and stepwise linear regression models were used to explore the relationship among morphology, kinematics (medial-lateral shift/tilt), and pain.

RESULTS

Relative to controls, adolescents with patellofemoral pain had larger sulci (mean ± SD, 6.6 ± 0.7 vs 6.0 ± 1.1 mm; 95% CI, 0.6 mm; P = .043; d = 0.66), lateral patellar width (23.1 ± 2.4 vs 21.4 ± 2.6 mm; 95% CI, 1.6 mm; P = .033; d = 0.70), and patella-trochlear width ratio (1.2 ± 0.1 vs 1.1 ± 0.1; 95% CI, 0.1; P < .001; d = 1.26). Shape correlated with kinematics in both cohorts and in the entire population. In the patellofemoral pain group, lateral shaft length (r = 0.518; P = .019), Wiberg index (r = 0.477; P = .033), and patellar-height ratio (r = -0.582; P = .007) were correlated with medial shift. A moderate correlation existed between patellar-height ratio and lateral patellar tilt (r = 0.527; P = .017). Half of the variation in patellar shift in the patellofemoral pain cohort was explained by the patellar-height ratio and Wiberg index (R² = 0.487; P = .003). Linear correlations with pain were not found.

CONCLUSION

This study provides direct evidence that patellofemoral morphology is altered and influences maltracking in adolescents with patellofemoral pain, highlighting the multifactorial etiology of this pain. Neither morphology nor kinematics (measured during active flexion-extension) correlated with pain. Both increases and decreases in these parameters likely lead to pain, negating a direct linear correlation.

Patellofemoral pain: One year results of a randomized trial comparing hip exercise, knee exercise, or free activity

OBJECTIVE

Extended follow-up of a randomized trial comparing hip-focused exercise, knee-focused exercise, and free physical activity in patellofemoral pain (PFP).

METHODS

A single-blind randomized controlled trial included 112 patients aged 16-40 years (mean 27.6 years) with a clinical diagnosis of PFP ≥3 months (mean 39 months) and pain ≥3/10 on a Visual Analog Scale. Patients were randomized to a 6-week exercise-based intervention consisting of either isolated hip-focused exercises (n = 39), traditional knee-focused exercise (n = 37), or free physical activity (n = 36). All patients received the same patient education. The primary outcome measure was the Anterior Knee Pain Scale (AKPS, 0-100). Secondary outcomes were usual and worst pain, Tampa Scale of Kinesiophobia, Knee Self-Efficacy Score, Euro-Qol (EQ-5D-5L), step-down test, and isometric strength. Blinded observers assessed outcomes at baseline, 3, and 12 months. The study was designed to detect a difference in AKPS >10 at 12 months.

RESULTS

After 1 year, there were no significant between-group differences in any primary or secondary outcomes. Between-group differences for AKPS were as follows: knee versus free physical activity -4.3 (95% CI -12.3 to 3.7); hip versus free physical activity -1.1 (95% CI -8.9 to 6.7); and hip versus Knee 3.2 (95% CI -4.6 to 11.0). The cohort as a whole improved significantly at 3 and 12 months compared to baseline for all measures except for knee extension strength.

CONCLUSION

After 1 year, there was no difference in effectiveness of knee exercise, hip exercise, or free physical activity, when combined with patient education in PFP.

Targeted Treatment Protocol in Patellofemoral Pain: Does Treatment Designed According to Subgroups Improve Clinical Outcomes in Patients Unresponsive to Multimodal Treatment?

BACKGROUND

Targeted intervention for subgroups is a promising approach for the management of patellofemoral pain.

HYPOTHESIS

Treatment designed according to subgroups will improve clinical outcomes in patients unresponsive to multimodal treatment.

STUDY DESIGN

Prospective crossover intervention.

LEVEL OF EVIDENCE

Level 3.

METHODS

Patients with patellofemoral pain (PFP; n = 61; mean age, 27 ± 9 years) were enrolled. Patients with PFP received standard multimodal treatment 3 times a week for 6 weeks. Patients not responding to multimodal treatment were then classified into 1 of 3 subgroups (strong, weak and tight, and weak and pronated foot) using 6 simple clinical tests. They were subsequently administered 6 further weeks of targeted intervention, designed according to subgroup characteristics. Visual analog scale (VAS), perception of recovery scale (PRS), 5-Level European Quality 5 Dimensions (EQ-5D-5L), and self-reported version of the Leeds Assessment of Neuropathic Symptoms and Signs scale (S-LANSS) were used to assess pain, knee function, and quality of life before and after the interventions.

RESULTS

In total, 34% (n = 21) of patients demonstrated recovery after multimodal treatment. However, over 70% (n = 29/40) of nonresponders demonstrated recovery after targeted treatment. The VAS, PRS, S-LANSS, and EQ-5D-5L scores improved significantly after targeted intervention compared with after multimodal treatment (P < 0.001). The VAS score at rest was significantly lower in the "weak and pronated foot" and the "weak and tight" subgroups (P = 0.011 and P = 0.008, respectively). Posttreatment pain intensity on activity was significantly lower in the "strong" subgroup (P = 0.006).

CONCLUSION

Targeted treatment designed according to subgroup characteristics improves clinical outcomes in patients unresponsive to multimodal treatment.

CLINICAL RELEVANCE

Targeted intervention could be easily implemented after 6 simple clinical assessment tests to subgroup patients into 1 of 3 subgroups (strong, weak and tight, and weak and pronated foot). Targeted interventions applied according to the characteristics of these subgroups have more beneficial treatment effects than a current multimodal treatment program.

Patellofemoral Pain

Patellofemoral pain (PFP) is a common musculoskeletal-related condition that is characterized by insidious onset of poorly defined pain, localized to the anterior retropatellar and/or peripatellar region of the knee. The onset of symptoms can be slow or acutely develop with a worsening of pain accompanying lower-limb loading activities (eg, squatting, prolonged sitting, ascending/descending stairs, jumping, or running). Symptoms can restrict participation in physical activity, sports, and work, as well as recur and persist for years. This clinical practice guideline will allow physical therapists and other rehabilitation specialists to stay up to date with evolving PFP knowledge and practices, and help them to make evidence-based treatment decisions. J Orthop Sports Phys Ther. 2019;49(9):CPG1-CPG95. doi:10.2519/jospt.2019.0302.

Toward the Development of Data-Driven Diagnostic Subgroups for People With Patellofemoral Pain Using Modifiable Clinical, Biomechanical, and Imaging Features

BACKGROUND

Unfavorable treatment outcomes for people with patellofemoral pain (PFP) have been attributed to the potential existence of subgroups that respond differently to treatment.

OBJECTIVES

This study aimed to identify subgroups within PFP by combining modifiable clinical, biomechanical, and imaging features and exploring the prognosis of these subgroups.

METHODS

This was a longitudinal cohort study, with baseline cluster analyses. Baseline data were analyzed using a 2-stage cluster analysis; 10 features were analyzed within 4 health domains before being combined at the second stage. Prognosis of the subgroups was assessed at 12 months, with subgroup differences reported as global rating of change and analyzed with an exploratory logistic regression adjusted for known confounders.

RESULTS

Seventy participants were included (mean age, 31 years; 43 [61%] female). Cluster analysis revealed 4 subgroups: "strong," "pronation and malalignment," "weak," and "active and flexible." Descriptively, compared to the strong subgroup (55% favorable), the odds of a favorable outcome were lower in the weak subgroup (31% favorable; adjusted odds ratio [OR] = 0.30; 95% confidence interval [CI]: 0.07, 1.36) and the pronation and malalignment subgroup (50%; OR = 0.64; 95% CI: 0.11, 3.66), and higher in the active and flexible subgroup (63%; OR = 1.24; 95% CI: 0.20, 7.51). After adjustment, compared to the strong subgroup, differences between some subgroups remained substantive, but none were statistically significant.

CONCLUSION

In this relatively small cohort, 4 PFP subgroups were identified that show potentially different outcomes at 12 months. Further research is required to determine whether a stratified treatment approach using these subgroups would improve outcomes for people with PFP.

LEVEL OF EVIDENCE

Diagnosis, level 2b. J Orthop Sports Phys Ther 2019;49(7):536-547. doi:10.2519/jospt.2019.8607.

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.

A proximal progressive resistance training program targeting strength and power is feasible in people with patellofemoral pain

OBJECTIVES

To evaluate the feasibility of a 12-week progressive resistance training program for people with patellofemoral pain (PFP) targeting proximal muscle strength and power; and resulting clinical and muscle capacity outcomes.

DESIGN

Feasibility study.

SETTING

Clinical environment.

PARTICIPANTS

Mixed-sex sample of people with PFP.

MAIN OUTCOME MEASURES

Feasibility outcomes included eligibility, recruitment rate, intervention adherence, and drop-outs. Secondary outcomes included perceived recovery, physical function (AKPS and KOOS-PF), worst pain (VAS-cm), kinesiophobia (Tampa), physical activity (IPAQ), and hip strength (isometric and 10 repetition maximum) and power.

RESULTS

Eleven people, from 36 who responded to advertisements, commenced the program. One participant withdrew. Ten participants who completed the program reported improvement (3 completely recovered; 6 marked; and 1 moderate). Higher AKPS (effect size [ES] = 1.81), improved KOOS-PF (ES = 1.37), and reduced pain (ES = 3.36) occurred alongside increased hip abduction and extension dynamic strength (ES = 2.22 and 1.92, respectively) and power (ES = 0.78 and 0.77, respectively). Isometric strength improved for hip abduction (ES = 0.99), but not hip extension.

CONCLUSION

A 12-week progressive resistance training program targeting proximal muscle strength and power is feasible and associated with moderate-large improvements in pain, function, and hip muscle capacity in people with PFP. Further research evaluating the efficacy of progressive resistance training is warranted.

Effect of patellofemoral pain on foot posture and walking kinematics

Background Excessive pronation has been implicated in patellofemoral pain (PFP) aetiology and foot orthoses are commonly prescribed for PFP patients. Pronation can be assessed using foot posture tests, however, the utility of such tests depends on their association with foot and lower-limb kinematics. Research questions Do PFP participants compared with healthy participants (1) have a more pronated foot measured with static foot tests and a kinematic multi-segmental foot model and (2) is there an association between static foot posture and foot and lower limb kinematics during walking? Methods A case-control study including 22 participants (n = 11 PFP, 5 females per group, aged 24 ± 3 (mean ± SD) years) was conducted. Foot posture measures included Arch Height Ratio, Navicular Drop (ND), and Foot Posture Index. Between-group comparisons of foot posture, segment and joint angle magnitudes, and associations between foot posture and kinematic data during gait were evaluated. Results There were no group differences in foot posture tests and mean joint angles. PFP participants had greater internal rotation of the shank and rearfoot segments, and adduction of the mid- and forefoot in the transverse plane (all p < 0.05). Greater ND was associated with increased forefoot abduction (rho=-0.68, p = 0.02) in healthy participants but no relationships were found between foot posture and kinematics in PFP participants. Significance Foot posture and kinematic data did not indicate excessive pronation in PFP participants questioning the use of orthoses to correct pronation. Larger studies are needed to determine the utility of foot posture tests as indicators of gait abnormalities in PFP.

Effectiveness of Isolated Hip Exercise, Knee Exercise, or Free Physical Activity for Patellofemoral Pain: A Randomized Controlled Trial

BACKGROUND

Exercise for patellofemoral pain (PFP) is traditionally knee focused, targeting quadriceps muscles. In recent years, hip-focused exercise has gained popularity. Patient education is likely an important factor but is underresearched.

PURPOSE

To compare 3 treatment methods for PFP, each combined with patient education: hip-focused exercise, knee-focused exercise, or free physical activity.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A single-blind randomized controlled trial was performed with 112 patients who were 16 to 40 years old (mean, 27.6 years) and had a symptom duration >3 months (mean, 39 months) with a clinical diagnosis of PFP and no radiograph or magnetic resonance evidence of other pathology. Patients were randomized to a 6-week intervention consisting of patient education combined with isolated hip-focused exercise (n = 39), traditional knee-focused exercise (n = 37), or free physical activity (n = 36). The primary outcome was Anterior Knee Pain Scale (0-100) at 3 months. Secondary outcomes were visual analog scale for pain, Tampa Scale for Kinesiophobia, Knee Self-efficacy Scale, EuroQol, step-down, and isometric strength.

RESULTS

There were no between-group differences in any primary or secondary outcomes at 3 months except for hip abduction strength and knee extension strength. Between-group differences at 3 months for Anterior Knee Pain Scale were as follows: knee versus control, 0.2 (95% CI, -5.5 to 6.0); hip versus control, 1.0 (95% CI, -4.6 to 6.6); and hip versus knee, 0.8 (95% CI, -4.8 to 6.4). The whole cohort of patients improved for all outcomes at 3 months except for knee extension strength.

CONCLUSION

The authors found no difference in short-term effectiveness in combining patient education with knee-focused exercise, hip-focused exercise, or free training for patients with PFP.

REGISTRATION

NCT02114294 (ClinicalTrials.gov identifier).

A loaded self-managed exercise programme for patellofemoral pain: a mixed methods feasibility study

BACKGROUND

A novel loaded self-managed exercise programme that includes pain education and self-management strategies may result in better outcomes for people with patellofemoral pain (PFP). However, establishing program feasibility is an essential first step before testing efficacy. The purpose of this study was to evaluate the feasibility and acceptability of conducting a definitive RCT which will evaluate the clinical and cost-effectiveness of a loaded self-managed exercise programme for people with PFP compared with usual physiotherapy.

METHODS

In a mixed methods, pragmatic, randomised controlled feasibility study, 60 participants with PFP (57% female; mean age 29 years) were recruited from a physiotherapy clinic within a large UK teaching hospital. They were randomly allocated to receive either a loaded self-managed exercise programme (n = 30) or usual physiotherapy (n = 30). Feasibility indicators of process, resources, and management were collected through follow-up of standardised questionnaires six months after recruitment and semi-structured interviews with 20 participants and physiotherapists.

RESULTS

Recruitment rate was 5 participants per month; consent rate was 99%; adherence to intervention appointments was 87%; completeness of questionnaire data was 100%; and adherence to intervention delivery was 95%. Three exercise diaries were returned at six months (5%). At six months, 25 questionnaire booklets were returned (9 in the loaded self-managed group, 16 in the usual physiotherapy group), with a total retention rate of 42%. At six months, 56% (5/9) of respondents in the loaded self-managed group and 56% (9/16) in the usual physiotherapy group were classified as 'recovered'. Both groups demonstrated improvements in average pain (VAS), kinesiophobia, pain catastrophizing, general self-efficacy and EQ-5D-5 L from baseline to six months.

CONCLUSION

The results of this feasibility study confirm that it is feasible and acceptable to deliver a loaded self-managed exercise programme to adults with PFP in an NHS physiotherapy outpatient setting. However, between group differences in lost to follow up and poor exercise diary completion mean we are uncertain on some feasibility aspects. These methodological issues need addressing prior to conducting a definitive RCT.

TRIAL REGISTRATION

ISRCTN 35272486 . Registered 19th December 2016.

How does acute pain influence biomechanics and quadriceps function in individuals with patellofemoral pain?

OBJECTIVES

Beside pathophysiological factors, pain is believed to play a crucial role in the progression of patellofemoral pain (PFP). However, the isolated effect of pain on biomechanics and quadriceps function has not been investigated in PFP. Thus, this study aimed to investigate the effect of pain on quadriceps function and lower limb biomechanics in individuals with PFP.

METHODS

Twenty-one individuals with PFP (11 males and 10 females, age: 29.76 ± 6.36 years, height: 1.74 ± 0.09 m, mass: 70.12 ± 8.56 kg) were measured at two different occasions: when not and when experiencing acute pain. Peak quadriceps torque (concentric, eccentric and isometric) and arthrogenic muscle inhibition (AMI) were assessed. Three-dimensional motion analysis and surface electromyography of the quadriceps and hamstring muscles were collected during running, a single-leg-squat and step-down task. The normality was assessed using the Shapiro-Wilk test and a MANOVA was performed at the 95% confidence interval.

RESULTS

AMI increased significantly in acute pain. The net muscle activation of the knee extensors and flexors decreased during running in acute pain. The lower limb biomechanics and the quadriceps torque did not change in acute pain.

DISCUSSION

It appears that even if individuals with PFP experience pain they can still deliver maximal quadriceps contractions and maintain their moving patterns without biomechanical changes. However, the overall reduced activation of the quadriceps and the increased AMI indicate the presence of quadriceps inhibition in acute pain.

COMPARISON OF PATELLA ALIGNMENT AND CARTILAGE BIOMARKERS IN YOUNG ADULT FEMALES WITH AND WITHOUT PATELLOFEMORAL PAIN: A PILOT STUDY

BACKGROUND

Evidence suggests that individuals with patellofemoral pain (PFP) may develop patellofemoral joint osteoarthritis (PFJOA). Limited data exist regarding an absolute association between PFP and PFJOA. Understanding this relationship will support the need for early interventions to manage PFP.

HYPOTHESIS/PURPOSE

This study was conducted to determine if females with PFP have a patella position and cartilage biomarkers similar to individuals with PFJOA. It was hypothesized that females with PFP and excessive patella lateralization would have higher cartilage biomarker levels than controls. It also was hypothesized that a significant association would exist between pain and cartilage biomarker levels in subjects with excessive patella lateralization.

STUDY DESIGN

Single-occasion, cross-sectional, observational.

METHODS

Pain was assessed using a 10-cm visual analog scale (VAS) for activity pain over the previous week. Patella offset position (RAB angle) was measured using diagnostic ultrasound. Urine was collected and cartilage biomarkers quantified by analyzing C-telopeptide fragments of type II collagen (uCTX-II). Independent t-tests were used to determine between-group differences for RAB angle and uCTX-II. Bivariate correlations were used to determine associations between VAS and uCTX-II for females with PFP.

RESULTS

Subjects (age range 20 to 30 years) had similar RAB angles (p = 0.21) and uCTX-II (p = 0.91). A significant association only existed between VAS scores and uCTX-II for females with PFP who had a RAB angle > 13 ° (r = 0.86; p = 0.003). Comparison of uCTX-II in the 25-to-30-year-old females with PFP and excessive patella lateralization in the current study to published normative data showed that this cohort had elevated biomarkers.

CONCLUSION

These findings support that a certain cohort of individuals with PFP have features similar to individuals with confirmed PFJOA (patella lateralization and elevated biomarkers). Additional studies are needed to determine if interventions can reverse not only pain but biomarker levels.

LEVEL OF EVIDENCE

2b (diagnosis).

Higher order thinking about differential diagnosis

BACKGROUND

Differential diagnosis is a systematic process used to identify the proper diagnosis from a set of possible competing diagnoses.

METHODS

The goal of this masterclass is to discuss the higher order thinking components of differential diagnosis.

CONCLUSIONS

For healthcare providers, diagnosis is one of many necessary components during the clinical decision making process and it is hallmarked by differentiation of competing structures for a definitive understanding of the underlying condition. The diagnostic process involves identifying or determining the etiology of a disease or condition through evaluation of patient history, physical examination, and review of laboratory data or diagnostic imaging; and the subsequent descriptive title of that finding. Whereas differential diagnosis is a varied skill set among all healthcare providers, the concept of a diagnosis is equally germane, regardless of one's background. In theory, a diagnosis improves the use of classification tools, improves clarity and communication, provides a trajectory of treatment, improves understanding of a person's prognosis, and in some cases, may be useful for preventative treatments. To achieve these improvements, one must have an understanding of relation of the clinical utility of tests and measures with diagnosis, and how to best implement these findings in clinical practice. This requires a deeper understanding (higher order thinking) of the role of diagnosis in the management of patients.

National Athletic Trainers' Association Position Statement: Management of Individuals With Patellofemoral Pain

OBJECTIVE: 

To present recommendations for athletic trainers and other health care providers regarding the identification of risk factors for and management of individuals with patellofemoral pain (PFP).

BACKGROUND: 

Patellofemoral pain is one of the most common knee diagnoses; however, this condition continues to be one of the most challenging to manage. Recent evidence has suggested that certain risk factors may contribute to the development of PFP. Early identification of risk factors may allow clinicians to develop and implement programs aimed at reducing the incidence of this condition. To date, clinicians have used various treatment strategies that have not necessarily benefitted all patients. Suboptimal outcomes may reflect the need to integrate clinical practice with scientific evidence to facilitate clinical decision making.

RECOMMENDATIONS: 

The recommendations are based on the best available evidence. They are intended to give athletic trainers and other health care professionals a framework for identifying risk factors for and managing patients with PFP.

Two-dimensional frontal plane projection angle can identify subgroups of patellofemoral pain patients who demonstrate dynamic knee valgus

BACKGROUND

Identifying individuals with patellofemoral pain who demonstrate similar modifiable factors including dynamic knee valgus may be useful in establishing subgroups of patients that can undergo individualised management strategies. However, a lack of objective assessment criteria means that the findings are of limited value to clinicians aiming to distinguish between patients with and without altered frontal plane knee kinematics. Therefore, the aim of the study was to investigate dynamic knee valgus in individuals with and without patellofemoral pain by determining frontal plane knee alignment during functional activity.

METHODS

Thirty recreationally active individuals with patellofemoral pain and 30 non-injured individuals had frontal plane knee alignment assessed via two-dimensional analysis of the frontal plane projection angle during single limb stance and single limb squats to 60° of knee flexion.

FINDINGS

Individuals with patellofemoral pain demonstrated excessive frontal plane knee alignment (P = .003; ES = 0.68) compared to uninjured participants during single limb squats. In addition, assessing frontal plane knee alignment using two-dimensional analysis had fair specificity and sensitivity of discriminating patellofemoral pain injury.

INTERPRETATION

Clinical quantification of two-dimensional frontal plane knee alignment may be utilised to subgroup patients with patellofemoral pain that display dynamic knee valgus during single limb squats. Furthermore, this may be a useful clinical tool to determine individuals that may be at risk of developing pain in the future.

Use of an Elastomeric Knee Brace in Patellofemoral Pain Syndrome: Short-Term Results

Purpose  This article verifies the effectiveness of a new brace on patellofemoral pain syndrome (PFPS) in adjunct to a specifically developed rehabilitation program. Methods  Two groups of 30 patients with PFPS were prospectively and randomly allocated to a rehabilitation protocol, with (group A) or without (group B) the use of a specific brace. All the patients were assessed at 3, 6, and 12 months using the disease-specific Kujala scale and a visual analog scale (VAS) for pain; time to return to sport and patient satisfaction with the brace were also recorded. Results  Kujala scale's values showed constant and progressive improvement. The mean score at 6 months was 79.8 ± 6.8 points in group A and 76.8 ± 8.6 in group B, rising at 12 months to 80.9 ± 7.5 in group A and 78.4 ± 8.3 in group B. VAS scores significantly differed ( p  < 0.05) between the two groups at both 6 and 12 months; the score recorded at 12 months was 0.9 ± 1.3 in the brace-treated group and 1.8 ± 1.6 in the controls. The patients who used a brace showed a quicker return to sports and 75% of the patients in this group were satisfied. Conclusion  All the scores improved progressively in both groups. The most significant improvement concerned pain, showing that the brace used in this study may allow a better subjective outcome and a quicker return to sport. Level of Evidence  Level II, prospective randomized controlled trial.

A sequential cognitive and physical approach (SCOPA) for patellofemoral pain: a randomized controlled trial in adolescent patients

Objective:

To compare a sequential treatment algorithm considering psychosocial and physical impairments, with a conventional rehabilitation approach considering only physical impairments in adolescents with patellofemoral pain.

Design:

A randomized, single-blind, controlled study.

Participants:

Fifty-five adolescents (36 females; mean age 14.3 ± 1.8 years).

Interventions:

The sequential cognitive and physical approach (SCOPA) group ( n = 28) was treated based on sequential testing and treatment of activity-related fear, flexibility, kinematics, and strength. The comparator group ( n = 27) was treated with a non-sequential physical impairment–based approach. Both groups received treatment two times a week for up to six weeks.

Measurements:

Function (Anterior Knee Pain Scale), pain (Numeric Pain Rating Scale), and Global Rating of Change were assessed at baseline, three weeks, and six weeks, with a six-month follow-up.

Results:

Both groups had similar function (73.7 ± 9.6) and pain (6.0 ± 2.3) at baseline. A third of individuals with patellofemoral pain demonstrated elevated activity-related fear at baseline. Patients randomized to the SCOPA group had clinically significant greater improvements at six weeks in function (SCOPA, 95.0 ± 7.4 and comparator, 84.8 ± 10.4; mean difference: 10.2, 95% CI: 5.3, 15.1) and pain (SCOPA, 0.9 ± 1.9 and comparator, 2.7 ± 2.1; mean difference: 1.7, 95% CI: 0.5, 2.9). No differences were noted in Global Rating of Change. No between-group differences were noted in any outcome at six-month follow-up.

Conclusion:

The sequential cognitive and physical approach resulted in greater improvements in short-term function and pain. By six months, both groups demonstrated similar clinically significant improvements in all outcomes.