Frontal Plane Biomechanics in Female and Male Participants With and Without Patellofemoral Pain Syndrome

Research Review: Frontal Plane Biomechanics in Females and Males With and Without Patellofemoral Pain Syndrome

By Tristan J. Rodik, M.AT., ATC

Edited By Brent Brookbush, DPT, PT, COMT, MS, PES, CES, CSCS, ACSM H/FS

Original Citation: Nakagawa, T. H., Moriya, E. T. U., Maciel, C. D. and Serrao, F. V. (2012) Frontal plane biomechanics in males and females with and without patellofemoral pain. Medicine and Science in Sports and Exercise, 44(9), 1747-1755. Abstract

Introduction: Altered kinematics, muscle activity, and strength have been correlated with patellofemoral pain syndrome (PFPS) (1-7). However, few studies investigate kinematics and muscle strength and/or muscle activity. This 2012 study investigated differences in kinematics, muscle activity, and muscle strength, and further compared differences between sexes. The findings from this study correlate PFPS with greater hip adduction, knee abduction, contralateral pelvic drop, and trunk lean, as well as less abductor torque and lower gluteus medius activity during functional tasks. Women with PFPS demonstrated larger differences than men.

Study Summary

Study Design	Correlation study
Level of Evidence	III Evidence from non-experimental descriptive studies, such as comparative studies, correlation studies, and case-control studies
Subject Characteristics	Demographics: Female with Patellofemoral Pain Syndrome (PFPS) Age: 22.44 +/- 3.24 Number of participants: 20 Height: 1.66 +/- 0.06 m Mass: 61.61+/- 7.84 kg Symptom Duration: 37.61 +/- 29.21 months Female Control Group Age: 21.94 +/- 2.71 Number of participants: 20 Height: 1.63 +/- 0.05 m Mass: 58.50 +/- 7.05 kg Males with PFPS Age: 23.56 +/- 3.24 Number of Participants: 20 Height: 1.81 +/- 0.05 m Mass: 77.56 +/- 9.17 kg Symptom duration: 30.39 +/- 14.39 months Male Control Group Age: 23.28 +/- 3.98 Number of Participants: 20 Height: 1.78 +/- 0.05 m Mass: 75.39 +/- 10.13 kg Inclusion Criteria (Male and Female PFPS): Recreationally active (participates in aerobic or other athletic activity at least 3x/week) Insidious onset of symptoms Presence of peri- or retro-patellar knee pain during at least two of the following activities: stair ascent or descent running kneeling squatting prolonged sitting jumping isometric quadriceps contraction palpation of medial and/or lateral patellar facet Inclusion Criteria (Male and Female Control Groups): No history of knee injury or pain Exclusion Criteria (All Participants): History of knee surgery History of back, hip or ankle joint injury or pain Patellar instability Symptoms of meniscal or knee ligament injury Neurological condition that affects gait
Methodology	The painful or most painful extremity was tested for all participants Prior to Testing: Participants completed a 5-minute warm-up on a treadmill (walking pace) Electrodes for electromyographic (EMG) analysis were placed along the gluteus medius Maximal voluntary isometric contraction (MVIC) testing was performed on the gluteus medius 1-practice trial, followed by 3-tested trials Each trial required a 5-second duration Electromagnetic tracking sensors were placed along the sternum, sacrum, distal lateral thigh and anteromedial aspect of the proximal tibia Participants then practiced the stepping maneuver Testing: Participants stood with the testing limb on an elevated surface. Participants then lowered themselves until the contralateral heel touched the floor. Once the heel touched the floor, participants raised themselves back to the starting position. A digital metronome set the pace at 15 steps per minute. Step height was set to 10% of each participant's height. Trials were invalid and repeated if participants lost balance.
Data Collection and Analysis	EMG signals were recorded at 2000Hz and detected with DE-3.1 sensors (Delsys, Inc., Boston, MA). Signals were then amplified by a Bagnoli™ eight-channel system (Delsys, Inc.). Raw EMG signals were band-pass filtered at 35-500 Hz and a 60-Hz notch filter was applied. Kinematic data were filtered using a fourth-order zero-lag low-pass Butterworth filter at 6 Hz. Euler angles were calculated using Motion-Monitor™ software. Kinematic and EMG data were reduced using custom MATLAB software (The MathWorks, Natick, MA). Statistical analysis was completed via SPSS software (version 17.0; SPSS, Inc., Chicago, IL). Kinematic data was compared between male and female PFPS participants with a three-way (sex x group x angles) mixed-model ANOVA's. knee flexion angles were set as the repeated measure Hip abductor torque was compared among all groups with a two-way (sex x group) ANOVA Bonferroni-adjusted t-tests assessed pairwise comparisons. Statistical significance was set to a p-value of 0.05.
Outcome Measures	Kinematic variables including: trunk lean, contralateral pelvic drop, hip adduction, and knee abduction. Kinematic variables were captured during the downward phase (15°, 30°, 45°, and 60° of knee flexion) and upward phase (15°, 30°, 45°, and 60° of knee flexion). EMG results were collected for the gluteus medius.
Results	Ipsilateral Trunk Lean Female controls demonstrated greater ipsilateral trunk lean compared to male controls (p = 0.022-0.001). For both sexes, PFPS participants showed greater ipsilateral trunk lean compared to controls in all phases except 15° and 30° of knee flexion (p < 0.001). Contralateral Pelvic Drop During the upward phase only female controls showed a significant decrease in pelvic drop compared with male controls (p = 0.027-0.001). For both sexes PFPS participants revealed greater contralateral pelvic drop during all angles (except 15° and 30° of knee flexion) when compared to controls (p = 0.034-0.001). Hip Adduction Female controls presented greater hip adduction for all angles when compared to male controls (p = 0.02-0.001). During the downward phase, PFPS participants for both sexes demonstrated increased hip adduction at all angles when compared to controls (except for 15° and 30° of knee flexion) (p = 0.021-0.001). Knee Abduction Female controls demonstrated significantly greater knee abduction during the downward and upward phases when compared to male controls (p = 0.007-0.001). For both sexes PFPS participants demonstrated significantly greater knee abduction than controls at all angles (p = 0.013-0.001). Gluteus Medius EMG Female controls showed greater gluteus medius activation at all angles (except 15° and 30° of knee flexion) when compared to male controls (p = 0.008-0.001). For both sexes PFPS participants demonstrated less gluteus medius activation compared to controls at 60° of knee flexion during the upward and downward phase (p = 0.015 and 0.005, respectively). Isometric Hip Abductor Torque Female controls showed less hip abductor torque than male controls (p < 0.001). For both sexes, PFPS participants showed less isometric hip abductor torque than controls (p < 0.001).
Our Conclusions	The findings reveal trends of increased ipsilateral trunk lean, contralateral pelvic drop, hip adduction, and knee abduction in participants with PFPS. Gluteus medius EMG and isometric hip abductor torque were also less in participants with PFPS when compared the control group. Women with PFPS demonstrated larger differences than men.
Researchers' Conclusions	Females with PFPS showed lower isometric hip abductor torque than males with PFPS. This coincided with increased hip adduction and knee abduction during the upward and downward phase of the stepping maneuver, and ipsilateral trunk lean and contralateral pelvic drop during the upward phase. These kinematic and strength variables should be targeted when managing prevention programs for knee injuries.

Biomechanical reflectors on an individual who exhibits excessive knee valgus, ipsilateral trunk lean and contralateral pelvic drop. (Courtesy of: http://www.xavierbarbier.com/online-courses/online-courses/2011/01/27/limportance-de-la-mobilite-de-la-cheville-partie-2/)

Why This Study is Important:

Although several studies have investigated factors correlated with patellofemoral pain syndrome (PFPS) separately, relatively few studies have investigated kinematics, muscle strength, muscle activity and sex differences together. The findings of this study may provide evidence of related factors correlated with PFPS. For example, those with PFPS had greater hip adduction, knee abduction, contralateral pelvic drop and trunk lean during stair decent, which may be explained by the additional findings of decreased gluteus medius activity and abductor strength. Although it may be logical to conclude that a decrease in gluteus medius activity would result in these changes; without a single study documenting all changes in the same participants, the relationships may only be inferred across studies. The addition of direct evidence of related factors correlated with PFPS may aid in better assessment and intervention selection.

How the Findings Apply to Practice:

Hip adduction, knee abduction (Knees Bow In ), contralateral pelvic drop (Trendelenberg Sign ) and trunk lean during a stair decent stepping task (similar to the Eccentric Step Down Test) may be a sign of gluteus medius weakness in those with PFPS. This may be useful during assessment; however, further research is needed to determine the reliability of these signs. Strengthening the glute medius has been shown to reduce pain and improve function in females with PFPS; more research is needed to determine the efficacy for males with PFPS (1, 2, 8-10).

This study had many methodological strengths, including:

Participant demographics were similar among gender-specific groups which should reduce the risk of confounding variables influencing outcomes.
The step down movement provided sufficient stimulus for recreational athletes to elicit signs of dysfunction, and can be easily administered by human movement professionals in various settings.
The position for abductor strength test was similar to the gluteus medius manual muscle testing recommended by the Brookbush Institute. The test is easily implemented improving replicability and applicability of the study.
The study investigated a variety of factors that may contribute to PFPS, allowing for direct correlation and implication of relationships.

Weaknesses that should be noted prior to clinical integration:

The participants were young and recreationally active, limiting the generalizability of the findings.
The stepping maneuver may be too demanding for sedentary, elderly and/or disabled individuals, limiting reproducibility for human movement professionals working with these populations
The electromyographic analysis only tested the gluteus medius and did not include other important muscles (such as the gluteus maximus , biceps femoris , TFL ).
The addition of range of motion measurements may have provided additional insights regarding the movement impairments correlated to PFPS.

How This Study is Related to Brookbush Institute Content:

The Brookbush Institute (BI) uses an integrated approach in addressing Lower Extremity Dysfunction (LED) , Lumbo Pelvic Hip Complex Dysfunction (LPHCD) and Sacroiliac Joint Dysfunction (SIJD) . These dysfunctions often include the impairments noted in this study: ipsilateral trunk lean, contralateral pelvic drop, hip adduction and/or knee abduction. Further, the gluteus medius is noted as under-active, and isolated activation of the gluteus medius is recommended as part of an integrated program. All programs should progress to integrated movement patterns, like stair climbing or step downs. The BI refines integrated exercise selection by considering the role of the Posterior Oblique Subsystem (POS) .

Sample Videos Related to the Research Study Content:

Gluteus Medius Manual Muscle Testing

Glute Activation Circuit

Gluteus Medius Progression (Activation Circuit)

Side Stepping Progressions for Reactive Activation of the Gluteus Medius

Bibliography:

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Glaviano, N. R., Huntsman, S., Dembeck, A., Hart, J. M. and Saliba, S. (2016) Improvements in kinematics, muscle activity and pain during functional tasks in females with patellofemoral pain following a single patterned electrical stimulation treatment. Clinical Biomechanics, 32, 20-27.
Nascimento, L. R., Teixeira-Salmela, L. F., Souza, R. B. and Resende, R. A. (2018) Hip and knee strengthening is more effective than knee strengthening alone for reducine pain and improving activity in individuals with patellofemoral pain: a systematic review with meta-analysis. Journal of Orthopaedic and Sports Physical Therapy, 48(1), 19-31
Carry, P. M., Gala, R., Worster, K., Kanai, S., Miller, N. H., James, D., Provance, A. J. and Carollo, J. J. (2017) Postural stability and kinetic change in subjects with patellofemoral pain after a nine-week hip and core strengthening intervention. International Journal of Sports Physical Therapy, 12(3), 314-323
Dolak, K. L., Silkman, C., Medina McKeon, J., Hosey, R. G., Lattermann, C. and Uhl, T. L. (2011) Hip strengthening prior to functional exercises reduces pain sooner than quadriceps strengthening in females with patellofemoral pain syndrome: a randomized clinical trial. Journal of Orthopaedic and Sports Physical Therapy, 41(8), 560-570

2018 Brent Brookbush

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