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BACKGROUND AND PURPOSE: Patellofemoral joint problems are the most common overuse injury of the lower extremity, and altered femoral or hip rotation may play a role in patellofemoral pain. The purpose of this case report is to describe the evaluation of and intervention for a patient with asymmetrical hip rotation and patellofemoral pain.
CASE DESCRIPTION: The patient was a 15-year-old girl with an 8-month history of anterior right knee pain, without known trauma or injury. Prior to intervention, her score on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was 24%. Right hip medial (internal) rotation was less than left hip medial rotation, and manual muscle testing showed weakness of the right hip internal rotator and abductor muscles. The intervention was aimed at increasing right hip medial rotation, improving right hip muscle strength (eg, the muscle force exerted by a muscle or a group of muscles to overcome a resistance), and eliminating anterior right knee pain.
OUTCOMES: After 6 visits (14 days), passive left and right hip medial rotations were symmetrical, and her right hip internal rotator and abductor muscle grades were Good plus. Her WOMAC score was 0%.
DISCUSSION: The patient had right patellofemoral pain and an uncommon pattern of asymmetrical hip rotation, with diminished hip medial rotation and excessive hip lateral (external) rotation on the right side. The patient's outcomes suggest that femoral or hip joint asymmetry may be related to patellofemoral joint pain.
A lot of work has been done recently on proximal control issues on PFPS ... it not all about foot orthoses and distal control issues.
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
I don't think this anything any of us didn't already know. Cibulka has a long history of looking at asymmetrical hip ROM and its effects on LBP and SI jt dysfunction and has quite extensively covered the topic. Only this time he looked at a case of PFD, with what he reports as an unusual pattern of restricted medial(internal) movement. No big deal. Take home message, hip ROM can influence knee symptoms. Not rocket science.
I was just cheking the refs on that paper an found this one from Chris Powers --- i missed it previously:
Foot Ankle Int. 2002 Jul;23(7):634-40 Comparison of foot pronation and lower extremity rotation in persons with and without patellofemoral pain.
Powers CM, Chen PY, Reischl SF, Perry J.
Abnormal foot pronation and subsequent rotation of the lower extremity has been hypothesized as being contributory to patellofemoral pain (PFP). The purpose of this study was to test the hypothesis that subjects with PFP would exhibit larger degrees of foot pronation, tibia internal rotation, and femoral internal rotation compared to individuals without PFP. Twenty-four female subjects with a diagnosis of PFP and 17 female subjects without PFP participated. Three-dimensional kinematics of the foot, tibia, and femur segments were recorded during self-selected free-walking trials using a six-camera motion analysis system (VICON). No group differences were found with respect to the magnitude and timing of peak foot pronation and tibia rotation. However, the PFP group demonstrated significantly less femur internal rotation compared the comparison group. These results do not support the hypothesis that individuals with PFP demonstrate excessive foot pronation or tibial internal rotation compared to nonpainful individuals. The finding of decreased internal rotation in the PFP group suggests that this motion may be a compensatory strategy to reduce the quadriceps angle.
__________________ Craig Payne
__________________________________________________ ___________________________________ Follow me on Twitter | Run Junkie God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
Tibia and rearfoot motion and ground reaction forces in subjects with patellofemoral pain syndrome during walking. Gait Posture. 2006 Feb 14;
Authors: Levinger P, Gilleard W
Abnormal subtalar joint function and the consequent rotation of the tibia during walking are thought to contribute to patellofemoral pain syndrome (PFPS). The purpose of this study was to measure rearfoot and tibia motion, and the ground reaction force (GRF) during the stance phase of walking in subjects with PFPS and compare them to healthy subjects. A four camera motion analysis system with a single force plate was used to investigate rearfoot motion relative to the tibia in three planes, the tibial transverse plane rotation and the GRF during the stance phase of walking in 13 female subjects diagnosed with PFPS and 14 healthy females. Analysis showed significantly delayed peak rearfoot eversion (p=0.02), and earlier occurrence of peak dorsiflexion (p=0.02) for the PFPS group. Furthermore, significantly lower peak medial GRF (p=0.03), minimum vertical GRF trough (p=0.02) and the second vertical GRF peak (p=0.01) were found in the PFPS group. Tibial transverse rotation was not shown to be different in PFPS subjects. However, there was prolonged rearfoot eversion during the stance phase of walking. The earlier appearance of rearfoot dorsiflexion as well as the lower GRFs indicate altered propulsive function of the foot during supination.
Background: Previous literature has associated hip weakness with patellofemoral pain syndrome.
Hypothesis: Improvements in hip strength and flexibility are associated with a decrease in patellofemoral pain.
Study Design: Cohort study; Level of evidence, 2.
Methods: Thirty-five patients with patellofemoral pain syndrome, aged 33 +mn; 16 years (29 women, 6 men; 43 knees), were evaluated and placed on a 6-week treatment program. Hip flexion, abduction, and adduction strengths, Thomas and Ober test results, and visual analog scale scores for pain with activities of daily living as well as with exercise were documented on initial evaluation and again 6 weeks later. Treatment consisted of strength and flexibility exercises primarily focusing on the hip.
Results: Hip flexion strength improved by 35% +mn; 8.4% in 26 lower extremities treated successfully, compared with –1.8% +mn; 3.5% in 17 lower extremities with an unsuccessful outcome (P < .001). Before treatment, there were positive Ober test results in 39 of 43 lower extremities; positive Thomas test results were seen in 31 of 43 lower extremities. A successful outcome with a concurrent normalized Ober test result was seen in 83% (20/24) of lower extremities, and successful outcomes with normalized Thomas test results were seen in 80% (16/20) of lower extremities. A combination of improved hip flexion strength (> 20%) as well as normal Ober and Thomas test results was seen in 93% of successfully treated cases (14/15 lower extremities), compared with 0% success (0/5 lower extremities) if there was no change in hip flexion strength (< 20%) and if Ober and Thomas test results remained positive.
Conclusions: Improvements in hip flexion strength combined with increased iliotibial band and iliopsoas flexibility were associated with excellent results in patients with patellofemoral pain syndrome
Well the tissue stress folks would say that you are looking at position and not moment or force. I have not been really happy with the pronation/ internal rotation theory of patella femoral pain. Transverse plane torque would be a key variable to look at. The idea is that the tibia is internally rotated relative to the femur. A difficult measure and still not torqure. For, me the jury is still out.
Hip Muscle Activity is Altered in Patellofemoral Pain: Clinical Implications
Crossley, Kay M.; Bryant, Adam; Cowan, Sallie
PURPOSE: It is commonly accepted that the aetiology of patellofemoral pain is mutifactorial. While many individuals have altered muscle function locally at the tibiofemoral or patellofemoral joints, it has been recognized by clinicians that hip muscle function (strength or co-ordination) may be impaired in individuals with patellofemoral pain. This study aimed to investigate whether individuals with patellofemoral pain have altered hip muscle function compared with their healthy counterparts. A further aim was to establish whether a simple clinical assessment of the single leg squat could identify individuals with altered hip muscle function
METHODS: Fifteen individuals with and without patellofemoral pain were recruited for this project. The electromyographic (EMG) of the gluteus medius muscles were collected during a stair stepping visual choice reaction time task. Anterior gluteus medius (AGM) was collected using surface electrodes, while posterior gluteus medius (PGM) was collected using fine wire electrodes. The onset of EMG activity of the gluteal muscles was assessed. Trunk side bend, hip external rotation and abduction torque were collected using a hand-held Nicholas Manual Muscle tester (model). The single leg squat performance was assessed by a panel of four experienced physical therapists. These clinicians reviewed a digital video recording of the participant performing five consecutive single leg squats. After reviewing the participants independently, the clinicians reached consensus on whether the participant could be graded as “good” or “poor”. Those participants who were classified as neither good nor poor were excluded from this analysis
RESULTS: Individuals with patellofemoral pain exhibited a later onset of both hip muscles (AGM and PGM) (p <0.05) than the healthy individuals. Interestingly, this alteration in the temporal control of the hip muscles was not associated with a deficit in hip muscle strength (p >0.05). Furthermore, individuals with poor performance on the clinical assessment of the single leg squat exhibited a delayed onset of the AGM and PGM.
CONCLUSIONS: Onsets of the AGM and PGM EMG is delayed in many individuals with patellofemoral pain. Furthermore, a simple clinical assessment tool is able to identify which individuals exhibit these temporal disruptions in hip muscle activity. In such individuals, clinicians should consider including an appropriate rehabilitation strategy
STUDY DESIGN: Cross-sectional. OBJECTIVES: To investigate whether females seeking physical therapy treatment for unilateral patellofemoral pain syndrome (PFPS) exhibit deficiencies in hip strength compared to a control group.
BACKGROUND: Decreased hip strength may be associated with poor control of lower extremity motion during weight-bearing activities, leading to abnormal patellofemoral motions and pain. Previous studies exploring the presence of hip strength impairments in subjects with PFPS have reported conflicting results.
METHODS AND MEASURES: Twenty females, aged 12 to 35 years, participated in the study. Ten subjects with unilateral PFPS were compared to 10 control subjects with no known knee pathologies. Hip abduction, extension, and external rotation strength were tested using a handheld dynamometer. A limb symmetry index (LSI) was used to quantify physical performance for all tests.
RESULTS: The symptomatic limbs of subjects with PFPS exhibited impairments in hip strength for all variables tested. LSI values in subjects with PFPS (range, 71%-79%) were significantly lower than those in control subjects (range, 93%-101%) (P< or =.007). A secondary analysis of data normalized to body mass demonstrated that the symptomatic limbs of subjects with PFPS had 52% less hip extension strength (P<.001), 27% less hip abduction strength (P = .007), and 30% less hip external rotation strength (P= .004) when compared to the weaker limbs of control subjects.
CONCLUSION: Females aged 12 to 35 presenting with unilateral PFPS demonstrate significant impairments in hip strength compared to control subjects when LSI values or body mass normalized values are used to quantify physical performance of the symptomatic limb.
PURPOSE: Decreased hip strength has been theorized to contribute to the development of patellofemoral pain. The purpose of this study was to test for strength differences of six hip muscle groups in collegiate female athletes diagnosed with unilateral patellofemoral pain compared with the unaffected leg and noninjured sport-matched controls.
METHODS: At four Division III schools, all collegiate female athletes experiencing unilateral patellofemoral pain were recruited during the 2004-2005 academic school year. The athletes were diagnosed with patellofemoral pain by sports medicine-trained family physicians or orthopedic surgeons. Hip strength of six different muscle groups was tested using a handheld dynamometer. The highest value of two trials was used, and strength values were normalized to body weight. The measurements from the injured leg were compared with the uninvolved leg and also with uninjured control subjects matched for sport.
RESULTS: Thirteen athletes were diagnosed with unilateral patellofemoral pain. The injured-side hip abductor (P = 0.003) and external rotator muscle groups (P = 0.049) were significantly weaker than the noninjured sides. There were no significant differences in the other hip muscles tested. In addition, the injured legs were significantly weaker in five of the six hip muscle groups compared with the control group.
CONCLUSIONS: The results of this study show that hip abductors and external rotators were significantly weaker between the injured and unaffected legs of the injured athletes. In addition, injured collegiate female athletes exhibited global hip weakness compared with age- and sport-matched asymptomatic controls. Screening for hip muscle weakness and adding strengthening exercises to the affected hip muscles may be important factors in managing female athletes with patellofemoral pain.
"Tibial transverse rotation was not shown to be different in PFPS subjects. However, there was prolonged rearfoot eversion during the stance phase of walking. The earlier appearance of rearfoot dorsiflexion as well as the lower GRFs indicate altered propulsive function of the foot during supination. "
Now this is something that makes perfect sense to me. It encompasses the paper that Craig P. listed and it's findings and includes some references to the timing of eversion during stance phase.
It is amazing to me that anyone would still think that the amount of measured in- or eversion of the heel, or internal rotation of the tibia would really matter. No matter the patient, they will usually fully pronate as much as their joints will allow. It is not a matter of what position they get to, but how long they stay in that position that really matters. This paper seems to verify that issue, to me at least.
I do not find it surprising that there would be a limitation of hip ROM either as this is often a compensation brought on by a stoppage of foot motion or rotation as recorded.
Call it a chicken / egg scenario if you like, but if you do not control for the pathologic foot function, your outcomes will rarely hold just by focusing on the hip musculature alone. IMHO!
STUDY DESIGN: Cross-sectional experimental laboratory study.
OBJECTIVES: To investigate the relationships between hip strength and hip kinematics, and between arch structure and knee kinematics during prolonged treadmill running in runners with and without patellofemoral pain syndrome (PFPS).
BACKGROUND: Hip weakness can lead to excessive femoral motions that adversely affect patellofemoral joint mechanics. Similarly, foot mechanics, which are influenced by foot structure, are also known to influence patellofemoral joint mechanics. Thus, proximal and distal factors should be considered when studying individuals with PFPS.
METHODS AND MEASURES: Twenty recreational runners with PFPS (5 male, 15 female) and 20 matched uninjured runners participated in the study. Hip abduction and hip external rotation isometric strength measurements were collected before and after a prolonged run, while the arch height index was recorded on all runners before the run. Lower extremity kinematic data were collected at the beginning and end of the run. Two-way repeated-measures analyses of variance (ANOVAs) were used for analysis.
RESULTS: Both groups displayed decreases in hip abductor and external rotator strengths at the end of the run. The PFPS group displayed significantly lower hip abduction strength [(kg x cm)/body mass] compared to controls (PFPS group: begin 15.3, end 13.5; uninjured group: begin 17.3, end 15.4). At the end of the run, the level of association between hip abduction strength and the peak hip adduction angle for the PFPS group was statistically significant, indicating a strong relationship (r = -0.74). No other associations with hip strength were observed in either group. Arch height did not differ between groups and no significant association was observed between arch height and peak knee adduction angle during running.
CONCLUSIONS: Runners with PFPS displayed weaker hip abductor muscles that were associated with an increase in hip adduction during running. This relationship became more pronounced at the end of the run.
Background: Recent studies have suggested that excessive hip internal rotation during dynamic tasks may be associated with patellofemoral pain. Although diminished hip-muscle strength and altered femoral morphologic characteristics have been implicated in abnormal hip rotation in persons with patellofemoral pain, no study has confirmed this hypothesis.
Hypothesis: Women with patellofemoral pain would demonstrate increased average hip internal rotation, decreased hip-muscle performance, and abnormal femoral shape compared with controls. Furthermore, measures of hip strength and femoral shape are predictive of average hip internal rotation during running.
Study Design: Cross-sectional study; Level of evidence, 3.
Methods: Nineteen women with patellofemoral pain and 19 pain-free controls participated. Lower extremity kinematics during running, hip-muscle performance, and femoral morphologic characteristics on magnetic resonance imaging were quantified. Independent t tests were used to assess group differences. Stepwise linear regression was used to determine whether measures of strength and/or structure were predictive of average hip internal rotation during running.
Results: Participants with patellofemoral pain demonstrated significantly greater average hip internal rotation (8.2° ± 6.6° vs 0.3° ± 3.6°; P < .001), reduced hip-muscle strength in 8 of 10 hip strength measurements, and greater femoral inclination (132.8° ± 5.2° vs 128.4° ± 5.0°; P = .011) compared with controls. Stepwise regression revealed that isotonic hip extension endurance was the only predictor of average hip internal rotation (r = –.451; P = .004).
Conclusion: Abnormal hip kinematics in women with patellofemoral pain appears to be the result of diminished hip-muscle performance as opposed to altered femoral structure. The results suggest that assessment of hip-muscle performance should be considered in the evaluation and treatment of patellofemoral joint dysfunction.
Tight lateral structures have been implicated in subjects presenting with patellofemoral pain syndrome (PFPS). It has been proposed that a tight iliotibial band (ITB) through its attachment of the lateral retinaculum into the patella could cause lateral patella tracking, patella tilt and compression.
Twelve subjects presenting with PFPS were compared with 12 matched control subjects. Hip adduction was measured using the Ober test in each subject as an indirect measure of ITB length. The mean values for hip adduction in the control group were 21.4 (±4.9) and 20.3 (±3.8) degrees in the left and right legs, respectively, and in the PFPS group, 17.3 (±6.1) and 14.9 (±4.2) degrees in the non-painful leg and painful leg, respectively. One way analysis of variance (ANOVA) revealed a highly significant difference between groups (F = 4.485, p = 0.008) and post-hoc analysis showed a significant difference between the painful leg in the PFPS group and the left and right legs in the control group, p = 0.002 and 0.009, respectively.
The results from this study show that subjects presenting with PFPS do have a tighter ITB. Future work should investigate this observation prospectively in order to determine whether a tight ITB is the cause or effect of PFPS.
Re: Patellofemoral pain and asymmetrical hip rotation
Press Release: Hip exercises found effective at reducing, eliminating common knee pain in runners.
A twice weekly hip strengthening regimen performed for six weeks proved surprisingly effective at reducing -- and in some cases eliminating -- knee pain referred to as patellofemoral pain (PFP) in female runners. The study by Tracy Dierks, assistant professor in the Department of Physical Therapy at Indiana University-Purdue University Indianapolis, was based on the theory that stronger hips would correct running form errors that contribute to PFP, even though study participants were given no instruction in gait training. The study used a pain scale of 0 to 10, with 3 representing the onset of pain and 7 representing very strong pain -- the point at which the runners normally stop running because the pain is too great. The injured runners began the six-week trial registering pain of 7 when they ran on a treadmill and finished the study period registering pain levels of 2 or lower; i.e. no onset of pain. "I wasn't expecting such huge reductions, to be honest," Dierks said. "We've had a couple of runners who have been at level 2, but the overwhelming majority have been a 2 or below."
About PFP and the study:
* PFP, one of the most common running injuries, is caused when the thigh bone rubs against the back of the knee cap. Runners with PFP typically do not feel pain when they begin running, but once the pain begins, it gets increasingly worse. Once they stop running, the pain goes away almost immediately. Dierks said studies indicate PFP essentially wears away cartilage and can have the same effect as osteoarthritis. His study participants showed many of the classic signs of PFP, the most prominent being their knees collapsing inward when running or doing a squat exercise move.
* The pilot study thus far involved five runners and a control group that comprised another four runners. Hip strength measurements were taken before and after the runners in the control group maintained their normal running schedule for six weeks. Hip strength measurements were taken for all of the runners before and after the next six-week period in which they all performed the hip-strengthening exercises. The exercises, performed twice a week for around 30 to 45 minutes, involved single-leg squats and exercises with a resistance band, all exercises that can be performed at home. This study is part of an ongoing study involving hip exercises and PFP pain, with 11 runners successfully using the intervention. Dierks said he plans to seek funding to test the exercises on a larger group of runners.
* Earlier research had focused on the feet as a possible root of PFP, with studies only recently looking more closely at the hips. Dierks said studies have found an association between PFP in women and weak hips, but his study is the first to test a possible treatment. He noted that PFP is considered "multi-factorial," so his study is examining one of several possible causes of the pain.
Background Patellofemoral pain syndrome (PFPS) is the most common overuse injury in runners. Recent research suggests that hip mechanics play a role in the development of this syndrome. Currently, there are no treatments that directly address the atypical mechanics associated with this injury.
Objective The purpose of this study was to determine whether gait retraining using real-time feedback improves hip mechanics and reduces pain in subjects with PFPS.
Methods Ten runners with PFPS participated in this study. Real-time kinematic feedback of hip adduction (HADD) during stance was provided to the subjects as they ran on a treadmill. Subjects completed a total of eight training sessions. Feedback was gradually removed over the last four sessions. Variables of interest included peak HADD, hip internal rotation (HIR), contralateral pelvic drop, as well as pain on a verbal analogue scale and the lower-extremity function index. We also assessed HADD, HIR and contralateral pelvic drop during a single leg squat. Comparisons of variables of interest were made between the initial, final and 1-month follow-up visit.
Results Following the gait retraining, there was a significant reduction in HADD and contralateral pelvic drop while running. Although not statistically significant, HIR decreased by 23% following gait retraining. The 18% reduction in HADD during a single leg squat was very close to significant. There were also significant improvements in pain and function. Subjects were able to maintain their improvements in running mechanics, pain and function at a 1-month follow-up. An unexpected benefit of the retraining was an 18% and 20% reduction in instantaneous and average vertical load rates, respectively.
Conclusions Gait retraining in individuals with PFPS resulted in a significant improvement of hip mechanics that was associated with a reduction in pain and improvements in function. These results suggest that interventions for PFPS should focus on addressing the underlying mechanics associated with this injury. The reduction in vertical load rates may be protective for the knee and reduce the risk for other running-related injuries.
STUDY DESIGN: Cross-sectional case control design.
BACKGROUND: Although the etiology of patellofemoral pain syndrome (PFPS) is not completely understood, there is some evidence to suggest that hip position during weight bearing activities contributes to the disorder.
OBJECTIVE: To compare the knee and hip motions (and their coordination) during stair stepping in female athletes with and without PFPS.
METHODS: Two groups of female recreational athletes, 1 group with PFPS (n=10) and the other without (n=10 control subjects) were tested. All subjects ascended and descended stairs (condition) at 2 speeds (self-selected comfortable and taxing, defined as 20% faster than the comfortable speed) while the knee and hip angles were measured with a magnetic-based kinematic data acquisition system. Angle-angle diagrams were used to examine the relationship between flexion/extension of the knee and flexion/extension, adduction/abduction, and internal/external rotation of the hip. The angle of the knee and the 3 angles of the hip at foot contact on the third step were compared between groups by means of 3-way analyses of variance (ANOVA) with repeated measures on speed and condition.
RESULTS: Group by speed interaction for knee angle was significant, with knee flexion being greater for the PFPS group for stair ascent and descent at a comfortable speed. Both the angle-angle diagrams and ANOVA demonstrated greater adduction and internal rotation of the hip in the individuals with PFPS compared to control subjects during stair descent.
CONCLUSION: Compared to control subjects, females with PFPS descend stairs with the knee in a more flexed position and have the hip in a more adducted and internally rotated position, at foot contact during stair stepping at a comfortable speed.
BACKGROUND: Proximal factors have been proposed to influence the biomechanics of the patellofemoral joint. A delayed or diminished gluteus medius (GM) activation, before the foot contact on the ground during functional activities could lead to excessive femur adduction and internal rotation and be associated with anterior knee pain (AKP). There are few studies on this topic and the results were inconclusive, therefore, it is necessary to investigate the GM preactivation pattern during functional activities.
OBJECTIVE: To compare the GM electromyographic (EMG) preactivation pattern during walking, descending stairs and in single leg jump task in women with and without AKP.
METHODS: Nine women clinically diagnosed with AKP and ten control subjects with no history of knee injury participated in this study. We evaluated GM EMG linear envelope before the foot contact on the ground during walking and GM onset time and EMG linear envelope during descending stairs as well as in a single leg vertical jump. Mann-Whitney U tests were used to determine the between-group differences in GM EMG preactivation pattern.
RESULTS: No between-group differences were observed in GM linear envelope during walking (P=0.41), GM onset time and linear envelope during descending stairs (P=0.17 and P=0.15) and single leg jump (P=0.81 and P=0.33).
CONCLUSIONS: Women with AKP did not demonstrated altered GM preactivation pattern during functional weight bearing activities. Our results did not support the hypothesis that poor GM preactivation pattern could be associated with AKP.
Background: Hip muscle weakness has been proposed to contribute to patellofemoral malalignment and the development of the patellofemoral dysfunction syndrome (PFDS). However, from the retrospective studies that have addressed this issue, it is still unclear if hip muscle weakness is a cause or a consequence of PFDS.
Purpose: This study was undertaken to investigate if hip muscle weakness is a predisposing factor for the development of PFDS.
Study Design: Cohort study (prognosis); Level of evidence, 2.
Methods: Before the start of a 10-week “start to run” program, the isometric strength of the hip flexor, extensor, abductor, adductor, and external and internal rotator muscles was measured in 77 healthy female novice runners. During the 10-week training period, patellofemoral pain was diagnosed and registered by an orthopaedic surgeon.
Results: Statistical analysis revealed that there was no significant difference in strength of any of the assessed hip muscle groups between the runners who did and did not develop PFDS. Logistic regression analysis did not identify a deviation in strength of any of the assessed hip muscle groups as a risk factor for PFDS.
Conclusion: The findings of this study suggest that isometric hip muscle strength might not be a predisposing factor for the development of PFDS.
Hip strengthening exercises performed by female runners not only significantly reduced patellofemoral pain -- a common knee pain experienced by runners -- but they also improved the runners' gaits, according to Indiana University motion analysis expert Tracy Dierks.
"The results indicate that the strengthening intervention was successful in reducing pain, which corresponded to improved mechanics," said Dierks, associate professor of physical therapy in the School of Health and Rehabilitation Sciences at Indiana University-Purdue University Indianapolis. "The leg was going through more motion, suggesting that the (pain) guarding mechanism was reduced, and coordination or control of many of these peak or maximum angles in the leg were improved in that they were getting closer to occurring at the same time."
Only in recent years have researchers begun studying the hips as a possible contributor to patellofemoral pain (PFP). This study is the first to focus on hip strength and gait changes during prolonged running. Dierks, director of the Motion Analysis Research Laboratory at IUPUI, discussed his findings on Wednesday at the American College of Sports Medicine annual meeting in Denver.
The runners in Dierks' study received no training or coaching on proper running form, which makes the improvements more notable. The improvements in mechanics resembled those of uninjured runners, when muscles, joints and limbs move economically and in synch with each other.
About the study
The study involved four runners and a control group comprised of another four runners. Hip strength measurements and kinematic data -- minute measurements of how the women's hips, knees and shin bones moved and rotated while they ran -- were taken before and after the runners in the control group maintained their normal running schedule for six weeks. The measurements were repeated for all of the runners before and after the next six-week period in which they all performed the hip-strengthening exercises.
The exercises, performed twice a week for around 30 to 45 minutes, involved single-leg squats and exercises with a resistance band, all exercises that can be performed at home. This study is part of an ongoing study involving hip exercises and PFP pain, with 10 runners successfully using the intervention.
After the six-week program, the movement of the hips and knees in relation to each other improved for both groups of runners, demonstrating increases in joint angles between the foot, shin and thigh.
The study used a pain scale of zero to 10, with 3 representing the onset of pain and 7 representing very strong pain -- the point at which the runners normally stop running because the pain is too great. The injured runners began the six-week trial registering pain of 7 when they ran on a treadmill and finished the study period registering pain levels of 2 or lower; i.e. no onset of pain.
PFP, one of the most common running injuries, is caused when the thigh bone rubs against the back of the knee cap. Runners with PFP typically do not feel pain when they begin running, but once the pain begins, it gets increasingly worse. Once they stop running, the pain goes away almost immediately. Dierks said studies indicate PFP essentially wears away cartilage and can have the same effect as osteoarthritis. His study participants showed many of the classic signs of PFP, the most prominent being their knees collapsing inward when running or doing a squat exercise move.
Co-authors of "The Effect Of Hip Muscle Strengthening On Pain and Running Mechanics In Females With Patellofemoral Pain" are Rebecca L. Phipps, Ryan E. Cardinal, Peter A. Altenburger, IUPUI.
Re: Patellofemoral pain and asymmetrical hip rotation
Hip Strengthening Prior to Functional Exercises Reduces Pain Sooner Than Quadriceps Strengthening in Females With Patellofemoral Pain Syndrome: A Randomized Clinical Trial
Kimberly L. Dolak, Carrie Silkman, Jennifer Medina McKeon, Robert G. Hosey, Christian Lattermann, Timothy L. Uhl J Orthop Sports Phys Ther 2011;41(8):560-570
STUDY DESIGN: Randomized clinical trial.
OBJECTIVES: To determine if females with patellofemoral pain syndrome (PFPS) who perform hip strengthening prior to functional exercises demonstrate greater improvements than females who perform quadriceps strengthening prior to the same functional exercises.
BACKGROUND: Although PFPS has previously been attributed to quadriceps dysfunction, more recent research has linked this condition to impairment of the hip musculature. Lower extremity strengthening has been deemed an effective intervention. However, research has often examined weight-bearing exercises, making it unclear if increased strength in the hip, quadriceps, or both is beneficial.
METHODS: Thirty-three females with PFPS performed either initial hip strengthening (hip group) or initial quadriceps strengthening (quad group) for 4 weeks, prior to 4 weeks of a similar program of functional weight-bearing exercises. Self-reported pain, function, and functional strength were measured. Isometric strength was assessed for hip abductors, external rotators, and knee extensors. A mixed-model analysis of variance was used to determine group differences over time.
RESULTS: After 4 weeks, there was less mean ± SD pain in the hip group (2.4 ± 2.0) than in the quad group (4.1 ± 2.5) (P = .035). From baseline to 8 weeks, the hip group demonstrated a 21% increase (P<.001) in hip abductor strength, while that remained unchanged in the quad group. All participants demonstrated improved subjective function (P<.006), objective function (P<.001), and hip external rotator strength (P = .004) from baseline to testing at 8 weeks.
CONCLUSION: Both rehabilitation approaches improved function and reduced pain. For patients with PFPS, initial hip strengthening may allow an earlier dissipation of pain than exercises focused on the quadriceps
Female runners have a high incidence of developing patellofemoral pain. Abnormal mechanics are thought to be an important contributing factor to patellofemoral pain. However, the contribution of abnormal trunk, hip, and foot mechanics to the development of patellofemoral pain within this cohort remains elusive. Therefore the aim of this study was to determine if significant differences during running exist in hip, trunk and foot kinematics between females with and without patellofemoral pain.
32 female runners (16 patellofemoral pain, 16 healthy control) participated in this study. All individuals underwent an instrumented gait analysis. Between-group comparisons were made for hip adduction, hip internal rotation, contra-lateral pelvic drop, contra-lateral trunk lean, rearfoot eversion, tibial internal rotation, as well as forefoot dorsiflexion and abduction
The patellofemoral pain group had significantly greater peak hip adduction and hip internal rotation. No differences in contra-lateral pelvic drop were found. A trend towards reduced contra-lateral trunk lean was found in the patellofemoral pain group. No significant differences were found in any of the rearfoot or forefoot variables but significantly greater shank internal rotation was found in the patellofemoral pain group.
We found greater hip adduction, hip internal rotation and shank internal rotation in female runners with patellofemoral pain. We also found less contra-lateral trunk lean in the patellofemoral pain group. This may be a potential compensatory mechanism for the poor hip control seen. Rehabilitation programs that correct abnormal hip and shank kinematics are warranted in this population.
Context: Quadriceps weakness and inhibition are impairments associated with patellofemoral pain syndrome (PFPS). Lumbopelvic joint manipulation has been shown to improve quadriceps force output and inhibition, but the duration of the effect is unknown.
Objective: To determine whether quadriceps strength and activation are increased and maintained for 1 hour after high-grade or low-grade joint mobilization or manipulation applied at the lumbopelvic region in people with PFPS.
Design: Randomized controlled clinical trial.
Setting: University laboratory.
Patients or Other Participants: Forty-eight people with PFPS (age = 24.6 ± 8.9 years, height = 174.3 ± 11.2 cm, mass = 78.4 ± 16.8kg) participated.
Intervention(s): Participants were randomized to 1 of 3 groups: lumbopelvic joint manipulation (grade V), side-lying lumbar midrange flexion and extension passive range of motion (grade II) for 1 minute, or prone extension on the elbows for 3 minutes.
Main Outcome Measure(s): Quadriceps force and activation were measured using the burst superimposition technique during a seated isometric knee extension task. A 2-way repeated-measures analysis of variance was performed to compare changes in quadriceps force and activation among groups over time (before intervention and at 0, 20, 40, and 60 minutes after intervention).
Results: We found no differences in quadriceps force output (F5.33,101.18 = 0.65, P = .67) or central activation ratio (F4.84,92.03 = 0.38, P = .86) values among groups after intervention. When groups were pooled, we found differences across time for quadriceps force (F2.66,101.18 = 5.03, P = .004) and activation (F2.42,92.03 = 3.85, P = .02). Quadriceps force was not different at 0 minutes after intervention (t40 = 1.68, P = .10), but it decreased at 20 (t40 = 2.16, P = .04), 40 (t40 = 2.87, P = .01) and 60 (t40 = 3.04, P = .004) minutes after intervention. All groups demonstrated decreased quadriceps activation at 0 minutes after intervention (t40 = 4.17, P < .001), but subsequent measures were not different from preintervention levels (t40 range, 1.53-1.83, P > .09).
Conclusions: Interventions directed at the lumbopelvic region did not have immediate effects on quadriceps force output or activation. Muscle fatigue might have contributed to decreased force output and activation over 1 hour of testing.
Re: Patellofemoral pain and asymmetrical hip rotation
The influence of heel height on patellofemoral joint kinetics during walking.
Ho KY, Blanchette MG, Powers CM. Gait Posture. 2012 Apr 18.
Although wearing high-heeled shoes has long been considered a risk factor for the development for patellofemoral pain (PFP) in women, patellofemoral joint kinetics during high-heeled gait has not been examined. The purpose of this study was to determine if heel height increases patellofemoral joint loading during walking. Eleven healthy women (mean age 25.0±3.1 yrs) participated. Lower extremity kinematics and kinetics were obtained under 3 different shoe conditions: low heel (1.27cm), medium heel (6.35cm), and high heel (9.53cm). Patellofemoral joint stress was estimated using a previously described biomechanical model. Model outputs included patellofemoral joint reaction force, patellofemoral joint stress and utilized contact area as a function of the gait cycle. One-way ANOVAs with repeated measures were used to compare the model outputs and knee joint angles among the 3 shoe conditions. Peak patellofemoral joint stress was found to increase significantly (p=0.002) with increasing heel height (low heel: 1.9±0.7MPa, medium heel: 2.6±1.2MPa, and high heel: 3.6±1.5MPa). The increased patellofemoral joint stress was mainly driven by an increase in joint reaction force owing to higher knee extensor moments and knee flexion angles. Our findings support the premise that wearing high-heeled shoes may be a contributing factor with respect to the development of PFP.
Re: Patellofemoral pain and asymmetrical hip rotation
Joint Range of Motion and Patellofemoral Pain in Dancers.
Steinberg N, Siev-Ner I, Peleg S, Dar G, Masharawi Y, Zeev A, Hershkovitz I. Int J Sports Med. 2012 May 4.
The aim of the present study was to determine the association between joint range of motion (ROM) and patellofemoral pain syndrome (PFPS) in young female dancers. The study population included 1 359 female dancers, aged 8-20 years. All dancers were clinically examined for current PFPS, and their joint ROM was measured at the lumbar spine and the lower extremities. 321 of the 1 359 dancers (23.6%) experienced PFPS. Prevalence of the syndrome increased with the dancer's age (p<0.001). Dancers with hypo ROM in hip external rotation, ankle plantar-flexion, ankle/foot pointe, hip abduction, hip extension, and limited hamstrings and lumbar spine were significantly less prone to developing PFPS compared to dancers with average ROM: 19.2% vs. 26.2% (p=0.014); 13.7% vs. 26.1% (p<0.001); 12.2% vs. 26.2% (p<0.001); 10.0% vs. 25.3% (p<0.001); 12.6% vs. 24.2% (p<0.001); and 9.3% vs. 28.2% (p<0.001), respectively. The group with the smallest prevalence of PFPS (10.2%) manifested restricted ROM at both the hip and ankle/foot joints. Dancers with decreased hip and ankle/foot joints ROM are less prone to develop PFPS. When making an association between joint ROM and injuries, not only the ROM at the targeted joint should be considered, but also the ROM at neighboring joints.