Different pain responses to distinct levels of physical activity in women with patellofemoral pain

The influence of pain exacerbation on rear foot eversion and plantar pressure symmetry in women with patellofemoral pain: a cross sectional study

BACKGROUND

The patellofemoral joint (PFJ) stress as a primary mechanical stimulus in the patellofemoral pain (PFP) etiology is affected by plantar pressure symmetry. This study evaluated how pain exacerbation affects rear foot eversion and plantar pressure distribution symmetry.

METHOD

Sixty women with PFP participated in this study. Pain intensity, rear foot eversion, and plantar pressure were evaluated in the two conditions with and without pain exacerbation during double-leg squats. The MANOVA test was used to compare pain intensity, rear foot eversion, and plantar pressure symmetry between the two conditions. The Pearson correlation was used to evaluate the relationship between the pain intensity with the rear foot eversion and the plantar pressure symmetry.

RESULTS

The comparison between the two conditions showed a significant difference in pain intensity (P < 0.001, η2 = 0.623), rear foot eversion (P < 0.001, η2 = 0.485), plantar pressure distribution symmetry of the right-left foot (P < 0.001, η2 = 0.438), forefoot and rear-foot of the right foot (P < 0.001, η2 = 0.607), and forefoot and rear-foot of the left foot (P < 0.001, η2 = 0.548). An excellent correlation was observed between the pain intensity with rear foot eversion (P < 0.001, r = 0.835) and plantar pressure distribution symmetry of the right-left foot (P < 0.001, r = 0.812), forefoot and rear-foot of the right foot (P < 0.001, r = 0.834), and forefoot and rear-foot of the left foot (P < 0.001, r = 0.811).

CONCLUSIONS

After the pain exacerbation, the rear foot eversion was greater, and plantar pressure asymmetrical was observed, which can help in the development of PFP severity.

Physical Activity Variability in Patellofemoral Pain: Relationships With Clinical and Psychological Outcomes

OBJECTIVES

To (1) compare physical activity variability between individuals with patellofemoral pain (PFP) and pain-free individuals and (2) evaluate the relationships of physical activity variability with pain severity, symptom duration, disability, and pain catastrophizing in PFP cohorts.

DESIGN

Cross-sectional case-control study.

SETTING

University research laboratory.

PARTICIPANTS

Individuals with PFP (N=34) and pain-free individuals (N=34) aged 18 to 40 years.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

We assessed physical activity (daily steps and moderate-to-vigorous physical activity [MVPA]) over a period of 14 consecutive days using a triaxial accelerometer. Variability (coefficient of variation) for daily steps and MVPA was calculated, where higher coefficient of variation values indicate greater physical activity variability. We evaluated pain severity (numeric pain rating scale), symptom duration (months), disability (Knee Injury and Osteoarthritis Outcome Score-Patellofemoral subscale), and pain catastrophizing (Pain Catastrophizing Scale). Independent t tests or Mann-Whitney U tests evaluated group differences in physical activity variability. Spearman ρ correlation coefficients were calculated to determine the relationships of physical activity variability with pain severity, symptom duration, disability, and pain catastrophizing in PFP cohorts. Correlation coefficients were interpreted as weak (<0.40), moderate (0.40-0.70), and strong (>0.70).

RESULTS

Age, height, and mass did not differ between individuals with PFP and pain-free individuals (P>.05). Individuals with PFP displayed greater variability in daily steps (P<.001) and MVPA (P=.001) compared to pain-free individuals. In individuals with PFP, greater variability in daily steps was moderately related to higher pain severity (ρ=0.41, P=.016), while greater variability in MVPA was weakly related to higher pain severity (ρ=0.36, P=.037).

CONCLUSIONS

Individuals with PFP demonstrated greater variability in physical activity compared to pain-free individuals, which positively related to more severe pain. Future PFP research should explore the underlying factors contributing to increased physical activity variability and their potential implications for pain management.

Influence of Pain, Risk Factors, and Functional Ability on Physical Activity Levels in Women with Anterior Knee Pain: A Cross-Sectional Study

Background and Objectives: Anterior knee pain (AKP) refers to chronic prepatellar pain and is one of the most common knee complaints in physically active women. This condition can significantly affect daily activities and overall quality of life. This study aims to assess the impact of pain, risk factors, and functional ability on different levels of physical activity (comparing low versus moderate activity) in women with AKP. Materials and Methods: This cross-sectional study involved fifty-six women diagnosed with AKP (aged 20-45 years) who were equally allocated into low and moderate physical activity groups. Their AKP and functional ability were assessed using the visual analog scale (VAS) and double squats and step-down tests, respectively. Possible risk factors were assessed using the Q-angle, modified Thomas test, sit and reach test, and patellar glide test. A person's correlation coefficient and independent t-tests were used to determine the relationship and the differences between these variables while keeping the confidence interval level at 95%. Result: Women with moderate activity levels showed significantly higher scores on the VAS than those with low activity levels (p = 0.040). However, both groups had no significant difference in their functional ability or potential risk factors (p > 0.05). Additionally, their functional ability (double squat) showed a positive association with hamstring flexibility (Pearson correlation coefficient [r]:0.3; p = 0.006). Conclusions: Women with AKP who were engaged in moderate physical activity experienced higher levels of pain compared to those with low activity levels. These findings underscore the urgent need for further investigation into different levels of physical activity to develop appropriate prevention and treatment strategies for women with AKP.

Physical Activity Levels in Persons With Patellofemoral Pain: A Systematic Review and Meta-analysis

CONTEXT

Pain and symptoms of patellofemoral pain (PFP) are often exacerbated during daily activities, which may result in reduced overall physical activity levels.

OBJECTIVE

To summarize the evidence for physical activity levels among persons with PFP compared with pain-free controls.

DATA SOURCES

PubMed, Embase, CINHAL, Cochrane Library, and SPORTDiscus were searched from January 1, 2000 to February 22, 2024.

STUDY SELECTION

Peer-reviewed studies published in English that measured physical activity subjectively or objectively in persons with PFP and pain-free controls.

STUDY DESIGN

Systematic review with meta-analysis.

LEVEL OF EVIDENCE

Level 1.

DATA EXTRACTION

Standardized mean difference (SMD) with 95% CI are reported based on Hedges' g effect sizes.

RESULTS

From 23,745 records, 41 studies met the eligibility criteria. There was high-to-moderate-certainty evidence that persons with PFP reported higher physical activity levels compared with pain-free controls using the International Physical Activity Questionnaire (SMD, 0.27; 95% CI 0.03, 0.51), whereas lower physical activity levels compared with pain-free controls using the Tegner Activity Scale (SMD, -0.31; 95% CI -0.57, -0.04). There was low-to-moderate-certainty evidence that there was no group difference in physical activity levels using the Baecke Physical Activity Questionnaire (SMD, 0.17; 95% CI -0.09, 0.44) or self-reported sports participation duration (SMD, -0.46; 95% CI -0.98, 0.05). There was high-certainty evidence that runners with PFP reported shorter running distances compared with pain-free runners (SMD, -0.36, 95% CI -0.57, -0.14). No data pooling was possible for objectively measured physical activity levels due to device heterogeneity (ie, different algorithms used to quantify the intensity of physical activity).

CONCLUSION

Self-reported physical activity levels among persons with PFP were inconsistent depending on the physical activity measurement tool used or which specific physical activity was measured. Clinicians should integrate multiple physical activity assessment tools to determine the extent to which PFP influences physical activity levels.

TRIAL REGISTRATION

PROSPERO #CRD42022314598.

Effects of pain exacerbation on postural control in women with patellofemoral pain during single leg squat: a cross-sectional study

BACKGROUND

The center of pressure (COP) excursion parameters are recognized as risk factors for the etiology and development of patellofemoral pain (PFP). The purpose of the present study measures the effect of pain exacerbation on COP excursion, and the correlation between pain intensity and COP excursion in women with PFP during single leg squat (SLS).

METHODS

Sixty patients with PFP participated in this cross-sectional study. The outcome measures were included pain intensity and COP excursion which evaluated in pre and post pain exacerbation during SLS. The COP parameters were evaluated during single leg squat in 60° of knee flexion. A paired t-test and MANOVA was used to compare pain intensity and COP excursion between the two conditions, respectively. Furthermore, A Pearson's correlation matrix was used to examine the relationship between pain intensity with COP excursion.

RESULTS

Statistical analysis showed that pain intensity (t = - 16.655, p < 0.001) and COP excursion (Wilks' Lambda = 0.225, p < 0.001) with medium effect size increased after PFJ loading. In addition, an excellent positive correlation was observed between increased in pain intensity and COP excursion (P < 0.001, r > 0.80).

CONCLUSION

After PFJ loading, women with PFP presented increases in the pain intensity, COP excursions, and sway velocity. In addition, there was an association between the increase in pain intensity and COP excursions. Clinicians aiming to improve postural control of patients with PFP could use kinesio taping as a short-term intervention and balance training to improvements in postural control at medium and long-term. Furthermore, emphasizing psychological factors to reducing kinesiophobia can be useful to restoring proper movement pattern, reducing pain and improving symptoms.

Relationship between exacerbating patellofemoral pain and dynamic knee valgus in females with patellofemoral pain after a patellofemoral joint loading protocol: A cross-sectional

OBJECTIVE

The aim of the present study is to 1) the effect of exacerbating patellofemoral pain (PFP) on dynamic knee valgus (DKV) 2) the relationship between exacerbating PFP and DKV in females with patellofemoral pain.

DESIGN

Cross-sectional study.

METHODS

Sixty women with PFP were recruited from the orthopedic clinics. We evaluated pain intensity and DKV in two conditions without (condition 1) and with (condition 2) PFJ loading during the single-leg squat (SLS) task. The MANOVA test was used to compare pain intensity and DKV angle between the two conditions. Furthermore, the Pearson correlation was used to examine the correlation between pain intensity with DKV angle.

RESULTS

The MANOVA analysis showed that pain intensity (P < 0.000, η2 = 0.623) and DKV angle (P < 0.000, η2 = 0.544) with a medium effect size significantly increased after PFJ loading. Furthermore, an excellent positive correlation was observed between an increase in pain intensity and DKV angle (P < 0.000, r = 0.840).

CONCLUSION

It seems that after the PFJ loading protocol and the subsequent pain exacerbation, the neuromuscular biomechanics of the lower limb are deficits. As a result, the stabilizing muscles activation decreases and increases the lower limb movement in the frontal plane.

Effects of an online program including mindfulness, exercise therapy and patient education compared to online exercise therapy and patient education for people with Patellofemoral Pain: protocol for a randomized clinical trial

BACKGROUND

Patellofemoral pain (PFP) is a common knee disorder that causes persistent pain, lower self-reported function and quality of life. People with PFP also present with altered psychological factors, which are associated with higher levels of pain and dysfunction. Mindfulness-based interventions (MBI) generally consist of meditative practices developed to provide a holistic approach to chronic conditions. However, the effects of MBI on clinical and psychological outcomes for people with PFP remains understudied.

METHODS

This assessor-blinded, parallel, two-arm randomized clinical trial aims to investigate the effects of adding an 8-week online MBI program to exercise therapy and patient education on clinical and psychological factors for people with PFP. We also aim to investigate whether psychological factors mediate changes in pain and function. Sixty-two participants with PFP will be recruited and randomized into one of two treatment groups (Mindfulness or Control group). Both groups will receive an 8-week intervention involving exercise therapy and education delivered through an online platform. The Mindfulness group will additionally receive a MBI component including formal and informal practices. Outcomes will be assessed online at baseline, intervention endpoint (follow-up 1) and 12 months after intervention completion (follow-up 2). Comparisons between groups will be performed at all time points with linear mixed models. A mediation analysis will be performed using a 3-variable framework.

DISCUSSION

Exercise therapy and patient education are considered the "best management" options for PFP. However, unsatisfactory long-term prognosis remains an issue. It is known that people with PFP present with altered psychological factors, which should be considered during the evaluation and treatment of people with PFP. Adding a MBI to the current best treatment for PFP may improve short and long-term effects by addressing the underlying psychological factors.

TRIAL REGISTRATION

Registro Brasileiro de Ensaios Clínicos (ReBEC) RBR-4yhbqwk, registered in April 6, 2021.

Body fat and skeletal muscle mass, but not body mass index, are associated with pressure hyperalgesia in young adults with patellofemoral pain

BACKGROUND

Young adults with patellofemoral pain (PFP) have a high prevalence of being overweight or obese, which is associated with impaired lower limb function and muscle weakness. However, the impact of being overweight or obese on pain sensitivity has not been explored.

OBJECTIVES

We investigated the association between body fat, skeletal muscle mass, and body mass index (BMI) with pressure hyperalgesia and self-reported pain in young adults with PFP.

METHODS

114 adults with PFP (24 ± 5 years old, 62% women) were recruited. Demographics and self-reported pain (current and worst knee pain intensity in the previous month - 0-100 mm visual analog scale) were recorded. Body fat and skeletal muscle mass were measured using bioelectrical impedance. Pressure hyperalgesia was measured using a handheld algometer (pressure pain threshold) at three sites: center of patella of the painful knee, ipsilateral tibialis anterior, and contralateral upper limb. The association between body fat, skeletal muscle mass, and BMI with pressure hyperalgesia and self-reported pain were investigated using partial correlations and hierarchical regression models (adjusted for sex, bilateral pain, and symptoms duration).

RESULTS

Higher body fat and lower skeletal muscle mass were associated with local, spread, and widespread pressure hyperalgesia (ΔR²=0.09 to 0.17, p ≤ 0.001; ΔR²=0.14 to 0.26, p<0.001, respectively), and higher current self-reported pain (ΔR²=0.10, p<0.001; ΔR²=0.06, p = 0.007, respectively). Higher BMI was associated with higher current self-reported pain (ΔR²=0.10, p = 0.001), but not with any measures of pressure hyperalgesia (p>0.05).

CONCLUSION

Higher body fat and lower skeletal muscle mass help to explain local, spread, and widespread pressure hyperalgesia, and self-reported pain in people with PFP. BMI only helps to explain self-reported pain. These factors should be considered when assessing people with PFP and developing their management plan, but caution should be taken as the strength of association was generally low.

Pain Variability and Subjective Function in Individuals With Patellofemoral Pain: A Short Report

Individuals with patellofemoral pain (PFP) experience discomfort during various functional activities. Long-term pain is a common consequence of PFP, yet little is known about daily pain variability. Our study consisted of 25 individuals with PFP who completed the Anterior Knee Pain Scale (AKPS) and recorded their daily pain over 10 days. Pain was evaluated using 2 measures of intensity (baseline pain, 10-day average pain) and 2 measures of variability (mean square of successive differences, probability of acute change). Associations between AKPS and the 4 pain measures were calculated with Pearson correlations. We calculated a linear regression to examine the amount of variance in the AKPS explained by the 4 pain measures. Greater mean square of successive differences values were moderately associated with lesser AKPS scores (r = -0.648, P < .001). Mean square of successive differences and 10-day averaged pain were the strongest predictors of AKPS (R2 = 0.565, P < .001). Pain variability provided a unique perspective on the pain experience and predicted patient-oriented function in individuals with PFP.

Impaired Isometric, Concentric, and Eccentric Rate of Torque Development at the Hip and Knee in Patellofemoral Pain

ABSTRACT

Ferreira, AS, de Oliveira Silva, D, Barton, CJ, Briani, RV, Taborda, B, Pazzinatto, MF, and de Azevedo, FM. Impaired isometric, concentric, and eccentric rate of torque development at the hip and knee in patellofemoral pain. J Strength Cond Res 35(9): 2492-2497, 2021-The aims of this study were to compare maximal muscle strength and rate of torque development (RTD) of knee extensor and hip abductor during isometric, concentric, and eccentric contractions between women with and without patellofemoral pain (PFP). Thirty-eight women with PFP (PFPG) and 38 pain-free women (CG) participated in this study. Isometric, concentric, and eccentric maximal torque and RTD of knee extensor and hip abductor were assessed using an isokinetic dynamometer. Rate of torque development was calculated as the change in torque over the change in time from torque onset to 30, 60, and 90% of the maximal torque (RTD30%, RTD60%, and RTD90%) during isometric, concentric, and eccentric contractions. PFPG had lower isometric, concentric, and eccentric knee extensor maximal torque (29.9, 28.3, and 26.7%) compared with the CG. For knee extensor RTD, PFPG had slower isometric RTD30% (17.8%), RTD60% (21.5%), and RTD90% (23.4%); slower concentric RTD30% (35.7%), RTD60% (29.3%), and RTD90% (28.2%); and slower eccentric RTD30% (20.5%), RTD60% (25.2%), and RTD90% (22.5%) compared with the CG. PFPG had lower isometric, concentric, and eccentric hip abductor maximal torque (28.3, 21.8, and 17%) compared with the CG. For hip abductor RTD, PFPG had slower isometric RTD30% (32.6%), RTD60% (31.1%), and RTD90% (25.4%); slower concentric RTD90% (11.5%); and slower eccentric RTD30% (19.8%), RTD60% (26.4%), and RTD90% (24%) compared with the CG. In conclusion, women with PFP presented deficits in both maximal strength and RTD of knee extensor and hip abductor during isometric, concentric, and eccentric contractions, which highlight the potential importance of addressing different aspects of muscle function through exercise therapy.

Knee flexor strength, rate of torque development and flexibility in women and men with patellofemoral pain: Relationship with pain and the performance in the single leg bridge test

OBJECTIVES

To investigate the relationship between: (1) knee flexor strength, rate of torque development (RTD), and flexibility with pain level; (2) knee flexor strength and RTD with the performance in the single leg bridge test (SLBT) in women and men with patellofemoral pain (PFP).

DESIGN

Cross-sectional.

SETTING

Laboratory-based study.

PARTICIPANTS

39 women and 36 men with PFP.

MAIN OUTCOME MEASURES

Knee flexor strength, RTD, and flexibility; performance in the SLBT, current, and worst pain level.

RESULTS

Moderate to strong significant negative relationships were identified between the current pain level with knee flexor strength (r = -0.57 to -0.34) and flexibility (r = -0.44 to -0.35); and between knee flexor strength and RTD with the performance in the SLBT (r = 0.34 to 0.57) in women and men with PFP. Knee flexor RTD was not related to any pain level and no significant relationships were identified between the worst pain level with knee flexor strength and flexibility in women and men with PFP.

CONCLUSIONS

Our results support the potential value of assessing knee flexor strength and flexibility in women and men with PFP. The SLBT may be a useful tool to assess knee flexor muscle capacity in individuals with PFP in a clinical setting.

Are hip and knee kinematics and training load characteristics relate to pain intensity and physical function level in runners with Patellofemoral Pain?

BACKGROUND

Patellofemoral pain (PFP) is the most common running-related injury. Altered hip and knee kinematics and increases in weekly distance and running pace are often associated with PFP development and exacerbation.

RESEARCH QUESTION

Are altered movements and training load characteristics (weekly distance and running pace) relate to pain intensity or physical function level in runners with PFP?

METHODS

Forty recreational runners with PFP (20 males and 20 females) participated in this cross-sectional observational study. Three-dimensional hip and knee kinematics were quantified during the stance phase of running. Weekly distance was defined as the average weekly kilometers of running and running pace as the average pace of the activity measured as minutes per kilometer. A visual analogue scale was used to evaluate worst knee pain during the last week. The anterior knee pain scale (AKPS) was used to evaluate knee functional score. A Pearson correlation matrix was used to investigate the association between each dependent variable (worst pain in the last week and AKPS score) and the independent variables (knee and hip kinematics, weekly distance and running pace).

RESULTS

There was no significantly correlation between kinematic variables, pain and functional score for both males and females separately and combined. Weekly distance (km/week) was found to positively correlate to pain intensity (r = 0.452; p < 0.05) in females with PFP. A simple linear regression revealed that weekly distance was significant predictor emerged of pain in females with PFP. Females exhibited significantly greater peak hip adduction and hip adduction ROM than the males and males had significantly greater running pace compared to females.

SIGNIFICANCE

Weekly distance should be considered in the clinical context during rehabilitation of PFP in females runners aiming at pain reduction.

Influence of the exacerbation of patellofemoral pain on trunk kinematics and lower limb mechanics during stair negotiation

BACKGROUND

Although it is assumed that the presence of patellofemoral pain (PFP) may result in compensatory behaviors that can alter trunk kinematics and lower limb mechanics, the influence of the exacerbation of patellofemoral pain on trunk kinematics and lower limb mechanics during stair negotiation has not been established.

RESEARCH QUESTION

Does the exacerbation of PFP symptoms lead to altered trunk kinematics and lower limb mechanics during stair negotiation?

METHODS

Three-dimensional kinematics and kinetics were obtained from 45 women with PFP during stair descent and ascent. Data were obtained before and after a pain exacerbation protocol. The variables of interest were peak trunk, hip, and knee flexion, and ankle dorsiflexion; peak hip, and knee extensor, and ankle plantarflexor moments. Paired t-tests were used to compare the variables of interest before and after pain exacerbation.

RESULTS

Following pain exacerbation, there was a decrease in peak knee extensor moment during stair descent (Effect size = -0.68; p = 0.01) and stair ascent (Effect size = -0.56; p = 0.02); as well as in peak ankle dorsiflexion during stair descent (Effect size = -0.33; p = 0.01) and stair ascent (Effect size = -0.30; p = 0.01). An increase in ankle plantarflexor moment during stair descent (Effect size = 0.79; p < 0.01) and stair ascent (Effect size = 0.89; p < 0.01) was also observed. No significant differences were observed for peak trunk, hip, and knee flexion or hip extensor moment (p > 0.05).

SIGNIFICANCE

Our findings show compensatory strategies used by people with PFP in response to symptoms exacerbation that may have a negative impact on knee and ankle mechanics. Our findings also suggest that people with PFP do not seem to change their trunk, hip, and knee flexion or hip extensor moment during stair negotiation in response to symptom exacerbation.

Novel Stepped Care Approach to Provide Education and Exercise Therapy for Patellofemoral Pain: Feasibility Study

Background

Patellofemoral pain (PFP) impairs joint- and health-related quality of life and may be associated with knee osteoarthritis. We developed a novel, 2-phase, stepped-care approach for PFP, combining (1) self-directed web-based education and exercise therapy with (2) physiotherapist-supported education and exercise therapy. Physiotherapy sessions can be provided using 2 different modalities: face-to-face and telerehabilitation.

Objective

This study aims to (1) determine the feasibility of our stepped-care approach, (2) explore patient-reported outcomes following self-directed web-based education and exercise therapy in people with PFP (phase 1), and (3) estimate the differences in treatment effects between face-to-face and telerehabilitation to support further education and exercise therapy (phase 2) in those who had not completely recovered following self-directed care.

Methods

Phase 1 involved 6 weeks of self-directed web-based education and exercise therapy. Phase 2 involved random allocation to a further 12 weeks of physiotherapist-led (up to 8 sessions) education and exercise therapy delivered face-to-face or via telerehabilitation to participants who did not rate themselves as completely recovered following phase 1. Feasibility indicators of process, adherence, and participant retention were collected as primary outcomes alongside patient-reported outcomes on Global Rating of Change and knee pain, disability, knee-related quality of life, pain catastrophism, kinesiophobia, and knee self-efficacy. All participants were assessed at baseline, 6 weeks, and 18 weeks.

Results

A total of 71 participants were screened to identify 35 participants with PFP to enter the study. Overall, 100% (35/35) and 88% (31/35) of the participants were followed up with at 6 and 18 weeks, respectively. In phase 1 of the study, participants accessed the My Knee Cap website for an average of 6 (7.5) days and performed the exercises for an average of 2.5 (3.6) times per week. A total of 20% (7/35) of the participants reported that they had completely recovered at 6 weeks. Furthermore, 93% (26/28) of the participants who were followed up and had not completely recovered at 6 weeks agreed to be enrolled in phase 2. No statistically significant differences were found between the face-to-face and telerehabilitation groups for any outcome. The novel stepped-care approach was associated with marked improvement or complete recovery in 40% (14/35) of the participants following phase 1 and 71% (25/35) of the participants following phase 2.

Conclusions

Self-directed web-based education and exercise therapy for people with PFP is feasible, as noted by the high rate of participant retention and home exercise adherence achieved in this study. Furthermore, 20% (7/35) of people reported complete recovery at 6 weeks. Both face-to-face and telerehabilitation physiotherapy should be considered for those continuing to seek care, as there is no difference in outcomes between these delivery modes. Determining the efficacy of the stepped-care model may help guide more efficient health care for PFP.

Impaired performance of women with patellofemoral pain during functional tests

OBJECTIVE

To compare the performance, reliability, and validity of functional tests between women with and without patellofemoral pain.

METHODS

Twenty women with a diagnosis of patellofemoral pain between 18 and 40 years of age and 20 age-matched pain-free controls participated in the study. All participants performed a set of five function tests: sitting-rising test, sit-to-stand in 30 seconds, stair-climb test, stair descent test, and six-minute step test. To investigate reliability, participants were assessed on two different days, seven days apart, by two independent investigators blinded to the results of the other investigator. Validity was evaluated through associations with the results on the Anterior Knee Pain Scale.

RESULTS

Performance in the tests was worse in women with patellofemoral pain than in the control group for the sit-to-stand in 30 seconds (mean difference [MD] 3.4reps; 95%CI: 0.4, 6.4), stair-climb test (MD: 0.36s; 95%CI: 0.1, 0.63), and six-minute step test (MD: 45reps; 95%CI: 20, 70). No differences were observed for the sitting-rising and stair descent tests. All tests in both groups showed moderate to excellent intra- and inter-rater reliability (intraclass correlation coefficients: 0.61 to 0.91 and 0.72 to 0.96, respectively). Finally, only the results on the sit-to-stand in 30 seconds test correlated with the Anterior Knee Pain Scale (r=0.44, p=0.047) in the patellofemoral pain group.

CONCLUSION

Women with patellofemoral pain present lower performance on some functional tests. Functional tests are reliable in patients with patellofemoral pain, although they are not associated with the results on the Anterior Knee Pain Scale self-questionnaire.

The relationship between urinary C-Telopeptide fragments of type II collagen, knee joint load, pain, and physical function in individuals with medial knee osteoarthritis

OBJECTIVE

Considering the osteoarthritis (OA) model that integrates the biological, mechanical, and structural components of the disease, the present study aimed to investigate the association between urinary C-Telopeptide fragments of type II collagen (uCTX-II), knee joint moments, pain, and physical function in individuals with medial knee OA.

METHODS

Twenty-five subjects radiographically diagnosed with knee OA were recruited. Participants were evaluated through three-dimensional gait analysis, uCTX-II level, the WOMAC pain and physical function scores, and the 40m walk test. The association between these variables was investigated using Pearson's product-moment correlation, followed by a hierarchical linear regression, controlled by OA severity and body mass index (BMI).

RESULTS

No relationship was found between uCTX-II level and knee moments. A significant correlation between uCTX-II level and pain, physical function, and the 40m walk test was found. The hierarchical linear regression controlling for OA severity and BMI showed that uCTX-II level explained 9% of the WOMAC pain score, 27% of the WOMAC physical function score, and 7% of the 40m walk test.

CONCLUSION

Greater uCTX-II level is associated with higher pain and reduced physical function and 40m walk test performance in individuals with medial knee OA.

What are the clinical implications of knee crepitus to individuals with knee osteoarthritis? An observational study with data from the Osteoarthritis Initiative

BACKGROUND

Crepitus is a common clinical feature of knee osteoarthritis. However, the importance of crepitus in the overall clinical presentation of individuals with knee osteoarthritis is unknown.

OBJECTIVE(S)

(A) To compare function, pain and quality of life between individuals with knee osteoarthritis with and without crepitus; (B) to compare whether individuals with knee osteoarthritis in both knees, but crepitus in just one, differ in terms of function pain, and knee strength.

METHODS

Setting: Observational study.

PARTICIPANTS

(A) A total of 584 participants with crepitus who had the same Kellgren-Lawrence grade on both knees were matched for gender, body mass index and Kellgren-Lawrence grade to participants without crepitus on both knees. (B) 361 participants with crepitus in only one knee and with the same Kellgren-Lawrence grade classification on both knees were included.

MAIN OUTCOME MEASURE(S)

A - Self-reported function, pain, quality of life, 20-m walk test and chair-stand test. B -Knee extensor and flexor strength, self-reported function and pain.

RESULTS

A - Individuals with crepitus had lower self-reported function, quality of life and higher pain compared to those without crepitus (3-11%; small effect=0.17-0.41, respectively). No difference was found in objective function between groups. B - Self-reported function was lower in the limb with crepitus compared to the limb without crepitus (15%; trivial effect=0.09). No difference was found in pain and knee strength between-groups.

CONCLUSION(S)

Individuals with knee osteoarthritis and knee crepitus have slightly lower self-reported physical function and knee-related quality of life (small or trivial effect). However, the presence of knee crepitus is not associated with objective function or knee strength.

The influence of sagittal trunk posture on the magnitude and rate of patellofemoral joint stress during stair ascent in asymptomatic females

BACKGROUND

Excessive patellofemoral joint stress (PFJS) is thought to be a contributory factor to patellofemoral pain (PFP). Thus, treatment strategies that minimize PFJS rate and magnitude during painful activities like stair ascent may be useful for optimizing outcomes for PFP patients. Sagittal plane trunk posture has been shown to influence PFJS during running although it is unknown if a similar relationship exists during stair ascent.

RESEARCH QUESTION

Does altering sagittal plane trunk posture affect PFJS rate and/or magnitude during stair ascent?

METHODS

Twenty asymptomatic females (23.4±2.5 yr; height: 164.4±7.9 cm; mass: 63.0±12.2 kg) performed 5 stair ascent trials (96 steps/min) during 3 conditions: self-selected trunk (SS), flexed trunk (FLX), and extended trunk (EXT). Three-dimensional kinematics (200 Hz) and ground reaction forces (2000 Hz) were collected during each trial. A previously described mathematical model was used to calculate PFJS that included subject-specific and non-subject-specific model inputs. Dependent variables included sagittal plane trunk angle, and the rates and magnitudes of PFJS, patellofemoral joint reaction force (PFJRF), and PFJ contact area during the stance phase of stair ascent.

RESULTS

Compared to SS, peak PFJS decreased during FLX (mean difference (MD)=2.6 MPa; p<0.001; 95%CI=2.2 to 2.9; effect size (ES)=5.2) and increased during EXT (MD=-3.3 MPa; p<0.001; 95%CI=-3.9 to -2.6; ES=-3.4). Similarly, PFJS rate decreased during FLX (MD=17.8 MPa/sec; p<0.001; 95%CI=13.6 to 21.9; ES=3.6) and increased during EXT (MD=-14 MPa/sec; 95%CI=-19.4 to -8.7; p<0.001; ES=-2.2).

SIGNIFICANCE

Sagittal plane trunk posture influences PFJS rate and magnitude during stair ascent in asymptomatic females. Increasing and decreasing forward trunk flexion resulted in decreased and increased PFJS respectively. Future studies should examine the effects of these movement strategy modifications on pain and function in patients with PFP.

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.

Relationship between knee abduction moment with patellofemoral joint reaction force, stress and self-reported pain during stair descent in women with patellofemoral pain

BACKGROUND

Increased external knee abduction moment has been proposed as a risk factor for patellofemoral pain. This alteration is thought to be associated with elevated patellofemoral joint reaction force and stress, however these relationships remain poorly explored. Therefore, this study aimed at comparing knee abduction moment parameters (peak, rate of moment development and impulse), patellofemoral joint reaction force and stress of women with patellofemoral pain and pain-free controls during stair descent; and investigating the relationship among these variables with self-reported pain.

METHODS

Kinetic data was obtained by inverse-dynamics equations and a previously reported algorithmic model was used to determine patellofemoral joint reaction force and stress. Participants' worst pain in the last month and pain level during stair descent were evaluated using a visual analogue scale.

FINDINGS

Women with patellofemoral pain presented higher peak, rate of moment development and impulse of the external knee abduction moment, patellofemoral joint reaction force and stress (p = 0.005 to 0.04, effect size = 0.52 to 0.96) during stair descent than pain-free controls. Only knee abduction moment impulse presented positive moderate correlations with worst pain level in the last month (r = 0.53, p < 000.1), pain level during stair descent (r = 0.33, p = 0.042), patellofemoral joint reaction force (r = 0.65, p < 000.1) and stress (r = 0.58, p < 000.1).

INTERPRETATION

These findings indicate that strategies aimed at decreasing external knee abduction moment impulse could reduce the load over the patellofemoral joint and improve pain of women with patellofemoral pain.

Quadriceps neuromuscular function in women with patellofemoral pain: Influences of the type of the task and the level of pain

The present study aimed at investigating whether the neuromuscular system behaves differently (in terms of force and muscle activity generation) as a function of the task being performed (i.e. maximal voluntary efforts vs stair negotiation) and the presence of patellofemoral pain (PFP) and possible influences of pain intensity. Thirty-eight women with (n = 19) and without PFP (n = 19) had their knee strength (extension joint torque) measured during maximal voluntary isometric contractions (MVIC) and electromyography (EMG) data recorded during both MVIC and stair ascent tasks, which were performed before and after a loading protocol designed to exacerbate pain symptoms. Women with PFP displayed lower levels of vastus medialis (p = 0.002) and vastus lateralis (p = 0.032) EMG activation during MVIC assessments. Conversely, the PFP group showed higher levels of vastus medialis muscle activity during stair climbing (p = 0.007), which happened exclusively after the loading protocol. Similarly, women with PFP displayed lower knee extensor torque only during the MVIC tests performed after the loading protocol, which was moderately correlated with the increase in self-reported pain (p = 0.041, r = 0.37), whereas the changes in EMG activity during stair ascent were not correlated with changes in pain intensity (p = 0.215, r = 0.12). These results suggest that, in comparison to pain-free controls, women with PFP display lower levels of quadriceps EMG activation during maximal contractions, but higher activation during dynamic tasks (stair ascent). In addition, the moderate association between the decrease in knee extensor torque and increase in self-reported pain indicates that care should be taken by clinicians during quadriceps strength evaluation in women with PFP, as misleading outcomes may emerge if the intensity of knee pain is not considered during screening. Additionally, rehabilitation strategies should focus on both restoring neuromuscular control and increasing muscle strength.

Knee crepitus is not associated with the occurrence of total knee replacement in knee osteoarthritis - a longitudinal study with data from the Osteoarthritis Initiative

OBJECTIVE(S)

To investigate whether the presence of knee crepitus is associated with the occurrence of total knee replacement (TKR), quality of life and deficits in physical function at long-term.

METHODS

Setting - This observational study uses longitudinal data (up to 4-year follow-up) from the Osteoarthritis Initiative (OAI). Participants - 4566 participants. Main Outcome Measure(s) - Logistic regression models were used to test if baseline knee crepitus is associated with the occurrence of TKR. Linear mixed models with adjustment for confounding variables (age, gender, BMI and Kellgren-Lawrence grade) were used to test the association between baseline knee crepitus and longitudinal changes in the pain, self-reported physical function, quality of life and performance-based function.

RESULTS

The presence of knee crepitus at baseline does not predict the occurrence of TKR at 36 months (p=0.58 and 0.67 for right and left knees, respectively). The crepitus group presented a slightly knee extension strength decline from baseline to 48 months (p=0.03 for the right and 0.01 for the left knee; between group difference=2% for both right [95%CI=-0.12; -0.01] and left knees [95%CI=-0.13; -0.02]).

CONCLUSION

The presence of knee crepitus is not associated with the occurrence of TKR in the following three years. Knee crepitus is associated with slightly declines in knee extension strength, but this does not seem to affect physical function and quality of life at long-term.

Knee crepitus is prevalent in women with patellofemoral pain, but is not related with function, physical activity and pain

OBJECTIVES

(i) To assess the reliability of knee crepitus measures, (ii) to investigate the association between knee crepitus and PFP; (iii) to investigate the relationship between knee crepitus with self-reported function, physical activity and pain.

DESIGN

Cross-sectional.

SETTING

Laboratory-based study.

PARTICIPANTS

165 women with PFP and 158 pain-free women.

MAIN OUTCOME MEASURES

Knee crepitus test, anterior knee pain scale (AKPS) and self-reported worst knee pain in the last month, knee pain after 10 squats and knee pain after 10 stairs climbing.

RESULTS

Knee crepitus clinical test presented high reliability Kappa value for PFP group was 0.860 and for pain-free group was 0.906. There is a significantly greater proportion of those with crepitus in the PFP group than in the pain-free group (OR = 4.19). Knee crepitus had no relationship with function (rpb = 0.03; p = 0.727), physical activity level (rpb = 0.010; p = 0.193), worst pain (rpb = 0.11; p = 0.141), pain climbing stairs (rpb = 0.10; p = 0.194) and pain squatting (rpb = 0.02; p = 0.802).

CONCLUSION

Women who presents knee crepitus have 4 times greater odds to be in a group with PFP compared to those who do not. However, knee crepitus has no relationship with self-reported clinical outcomes of women with PFP.

Association between increase in vertical ground reaction force loading rate and pain level in women with patellofemoral pain after a patellofemoral joint loading protocol

BACKGROUND

The etiology of patellofemoral pain (PFP) is thought to be the result of increased patellofemoral joint (PFJ) load and aberrant lower extremity mechanics, including altered vertical ground reaction forces (VGRF). However, few studies have investigated the association between an increase in pain and VGRF loading rates in the context of PFP. Thus, this study aimed to investigate the immediate effects of PFJ loading on pain and VGRF loading rate, and to see if there is a link between modification of both pain and VGRF loading rate during stair negotiation.

METHODS

Thirty-four women with PFP underwent VGRF analysis during stair negotiation under two conditions: with (condition 2) and without (condition 1) being previously submitted to a PFJ loading protocol in order to or not to exacerbate their knee pain, respectively.

RESULTS

The VGRF loading rates were significantly higher in condition 2 (Mean ± standard deviation (SD)=4.0±0.6N/s) compared to condition 1 (Mean±SD=3.6±0.5N/s) during stair ascent and during stair descent (Mean±SD: condition 1=6.3±1.1N/s; condition 2=7.0±1.4N/s). In addition, VGRF loading rates were higher during stair descent compared to stair ascent in both conditions. There were significant correlations between the increase in pain and VGRF loading rate during both tasks.

CONCLUSION

There seemed to be an important relation between the increase in pain and VGRF loading rates in women with PFP. Based on these findings, interventions aimed at reducing VGRF loading rates are important in the context of PFP.

DO MALES WITH PATELLOFEMORAL PAIN HAVE POSTEROLATERAL HIP MUSCLE WEAKNESS?

BACKGROUND

Patellofemoral pain is common in physically active adults. Females with patellofemoral pain have been shown to have posterolateral hip muscle weakness, but there is a paucity of research examining hip muscle strength in males with patellofemoral pain.

HYPOTHESIS/PURPOSE

The purpose of this study was to examine posterolateral hip muscle strength in males with patellofemoral pain compared to asymptomatic males. It was hypothesized that males with patellofemoral pain would have decreased strength of the hip extensor, hip external rotator, and hip abductor muscles compared to healthy, asymptomatic males.

STUDY DESIGN

Descriptive, cross-sectional.

METHODS

Thirty-six adult males with patellofemoral pain and 36 pain-free males participated in the study. The patellofemoral pain group were required to have retropatellar pain reproduced by activities that loaded the patellofemoral joint (squatting, descending stairs, etc.). Peak isometric torque of the hip extensors, hip external rotators, and hip abductors was measured with an instrumented dynamometer. Torque was normalized by body mass and height. Between-group differences were analyzed with parametric or non-parametric tests, as appropriate. The level of significance was adjusted for multiple comparisons.

RESULTS

Hip extensor torque was significantly reduced in the patellofemoral pain group compared to the control group (p = .0165). No differences were found between groups for the hip external rotators or hip abductors (p > .0167).

CONCLUSION

Males with patellofemoral pain appear to have weakness of the hip extensors, but unlike females with patellofemoral pain, they do not appear to have weakness of the hip abductors or hip external rotators. The findings of this study suggest that muscle strength factors associated with patellofemoral pain in males may be different from muscle strength factors in females. Clinicians examining and designing plans of care for male patients with patellofemoral pain should consider that the hip abductors and hip external rotators may not be weak in men with this condition.

LEVEL OF EVIDENCE

Level 3.

Do hip muscle weakness and dynamic knee valgus matter for the clinical evaluation and decision-making process in patients with patellofemoral pain?

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Hip muscle weakness in PFP patients may be consequence and not the cause of pain.

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Pain and disability may not be associated with kinematics after treatment.

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Hip muscle weakness may have no causal relationship with dynamic knee valgus.

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The mechanical factors that may impair the management of PFP are likely to be overestimated.

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PFP patients should be treated on a biopsychosocial approach.

Background

Patellofemoral pain is a very common musculoskeletal condition. In the last years, evidence regarding this disease increased exponentially. Although widely investigated, this problem still frustrates patients and clinicians for having an unfavorable prognosis. Some gaps still exist in the understanding and managing of patellofemoral pain. Numerous cross-sectional association studies show an association between gluteus muscular strength and dynamic knee valgus in patients with patellofemoral pain. In spite of this biological plausibility, many evidences challenge the direct relationship between these factors. Recent studies have concluded that women with patellofemoral pain show muscular weakness of the hip based on the cross-sectional studies, however prospective studies indicate that hip weakness cannot be considered a risk for development of patellofemoral pain. In addition, some clinical trials have demonstrated that strength training of the gluteal muscles promotes significant improvement in symptoms but not alter the kinematics of the patients with patellofemoral pain. These findings cast doubt on whether the cause of this condition is really being treated, whether all individuals suffering from patellofemoral pain present dynamic knee valgus or if this is a disturbance present in only a subgroup of patients and whether the strengthening of the hip musculature is an option to consider for prevention of patellofemoral pain.

Conclusion

Certainly, more studies should be conducted to clarify the influence of mechanical patterns on this condition, but with the existing evidence so far, the importance given to these issues in the evaluation and clinical decision on treatment of these patients seems questionable. Therefore, this masterclass explores the understanding about patellofemoral pain, highlighting mainly the importance of muscular strength and dynamic knee valgus, as well as other possible factors that must be consider during the evaluation and the decision making in these patients.

Diagnosis and treatment of movement system impairment syndromes

BACKGROUND

Diagnoses and treatments based on movement system impairment syndromes were developed to guide physical therapy treatment.

OBJECTIVES

This masterclass aims to describe the concepts on that are the basis of the syndromes and treatment and to provide the current research on movement system impairment syndromes.

RESULTS

The conceptual basis of the movement system impairment syndromes is that sustained alignment in a non-ideal position and repeated movements in a specific direction are thought to be associated with several musculoskeletal conditions. Classification into movement system impairment syndromes and treatment has been described for all body regions. The classification involves interpreting data from standardized tests of alignments and movements. Treatment is based on correcting the impaired alignment and movement patterns as well as correcting the tissue adaptations associated with the impaired alignment and movement patterns. The reliability and validity of movement system impairment syndromes have been partially tested. Although several case reports involving treatment using the movement system impairment syndromes concept have been published, efficacy of treatment based on movement system impairment syndromes has not been tested in randomized controlled trials, except in people with chronic low back pain.