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Michael M. Reinold, PT, DPT, SCS, ATC, CSCS
MikeReinold.com
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Solving the Patellofemoral Mystery
Michael M. Reinold, PT, DPT, SCS, ATC, CSCS
Chapter 1: Introduction Solving the patellofemoral mystery
Chapter 2: What causes patellofemoral pain?
Chapter 3: Differential diagnosis of patellofemoral pain
Chapter 4: Principles of patellofemoral joint rehabilitation
Chapter 5: Specific treatment guidelines for patellofemoral pain
Chapter 6: Biomechanics of the patellofemoral joint clinical implications
Chapter 7: Understanding the clinical implications of the kinetic chain: The influence of the hip and foot
on the patellofemoral joint
Chapter 8: Conclusion Have we solved the mystery?
MikeReinold.com
Copyright 2010 Michael Reinold, All Rights Reserved
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Chapter 1
Solving the Patellofemoral Mystery
Disorders of the patellofemoral joint continue to present assome of the most perplexing pathological conditions in
orthopedics and sports medicine. Previously described as
the black hole of orthopedics by Dr. Scott Dye, the
patellofemoral joint continues to cause dysfunction for
patients and confusion for clinicians. Patellofemoral pain
syndrome is often described as a diagnosis that tends to
result in poor outcomes. Despite years of research and
attention to the joint, the vague use of the term
patellofemoral pain syndrome continues to be prevalently abused used to categorize patients. This
becomes evident when analyzing the myriad of surgical and rehabilitative interventions that arecurrently being utilized to alleviate symptoms and restore function in patellofemoral patients. It appears
that a single surgical or rehabilitative approach cannot be efficaciously used to treat patellofemoral
disorders.
In this eBook, we will discuss the evaluation and treatment of the
patellofemoral joint with topics ranging from differential diagnosis
to treatment strategies that can be applied to any rehabilitation or
fitness program. My goal will be to develop an easy to understand
and implement system to treat patellofemoral pain based on an
accurate differential diagnosis and an understanding of the
normal biomechanics of the joint.
Throughout this ebook there will be several links to references on
the internet, anytime you see a blue underlined word or phrase, you can click that for more information.
I hope you enjoy this eBook and look forward to seeing you online soon!
Best,
Michael M. Reinold, PT, DPT, SCS, ATC, CSCS
Welcome to my new
eBook dedicated to evaluating
and treating the patellofemoral
joint.
Michael M. Reinold, PT, DPT, SCS, ATC, CSCS
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Chapter 2
The Source of Patellofemoral Pain
Patellofemoral disorders are often considered the most common knee pathology encountered byorthopedic and sports medicine clinicians. Some sources say that in the general population, 1 out of 4
will likely experience patellofemoral symptoms at some
time in their life. Although patellofemoral disorders
represent a common pathology, there is no consensus on
the optimal management of this condition. This may be
explained, in part, due to the various sources of pain that
may be contributing to the disorder. Unfortunately, terms
such as anterior knee pain and patellofemoral pain have become accepted diagnoses with
treatment often implemented without clear definitions of the underlying pathophysiology. The common
use of such ambiguous and non-specific terms only adds to the confusion regarding optimal care forthese patients.
Rehabilitation programs designed for the patellofemoral patient must match the specific disorder and
dysfunction. Chapter 4 of this series will discuss the differential diagnosis of patellofemoral pain,
however it is important to understand the source of patellofemoral pain in addition to any possible
diagnosis. In recent years, several authors have attempted to provide an explanation for the potential
source of patellofemoral pain.
Dye et al (AJSM 1998)examined the conscious
neurosensory mapping of the lead authors knee during
arthroscopy without intraarticular anesthesia (This in itself
is an amazing study, he literally had his partner scope his
own knee without anesthesia!). The authors rated the
level of conscious awareness from no sensation to severe
pain. These findings were further subdivided based on the
ability to accurately localize the sensation. Palpation to
the anterior synovial tissues, retinaculum, fat pad andcapsule produced moderate to severe pain that was
accurately localized. The insertion sites onto the tibia and
femur of the cruciate ligaments produced poorly localized
moderate to severe pain. Slight to moderate poorly localized sensation was produced at the capsular
margins. No sensation was detected on the patellar articular cartilage even though asymptomatic grade
II and III chondromalacia was noted on the central ridge the patella.
What Causes
Patellofemoral Pain?
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Within the clinical setting, patients often complain of diffuse patellofemoral
pain while undergoing physical examination. The results of this study may
provide an explanation for the vague description of pain that is often
reported by patellofemoral patients; the majority of structures palpated
produced poorly localized sensation.
The implications of this are interesting. It appears that degenerative
changes to the patellofemoral joint, or chondromalacia, was not a source of
pain. The author/subject didnt even know his patella had degenerative
changes. Numerous authors (Chrisman OD: Clin North AM 1986, Dye SF:
Orthop Clin North AM 1986, Fulkerson: Disorders of the Patellofemoral Joint
2004) have also documented that patellofemoral chondromalacia does not
necessarily produce patellofemoral pain. Based on the results of these
studies, it appears that the majority of patellofemoral symptoms may be
originating from the anterior synovial tissues, retinaculum, fat pad and
capsule, rather than from degeneration of the patellofemoral articular
surfaces.
Furthermore, several authors have also postulated that patellofemoral pain may originate in the lateral
retinacular soft tissues. Fulkerson et al (Clin Orthop 1985) performed a histological analysis on lateral
retinacular and underlying synovial tissue of patellofemoral patients biopsied during lateral retinacular
releases. These biopsies were compared to cadaveric specimens and biopsies taken from asymptomatic,
non-patellofemoral patients undergoing surgery to address anterolateral rotary instability. Nerve fibers
originating in the lateral retinaculum appeared enlarged with moderate lose of myelinated fibers in the
patellofemoral patient. The authors state that nerves within the retinaculum may degenerate from the
chronic stretching associate with muscular imbalances around the patellofemoral joint and present as a
potential source of patellofemoral pain.
It appears that the majority of patients complaining of
patellofemoral pain may originate from the surrounding soft
tissues and not from the osseous or articular cartilage
structures.
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Sanchis-Alfonso et al (AJSM 1998) biopsied the lateral
retinaculum of patients undergoing a lateral retinacular
release to address patellofemoral complaints. The authors
found neuromas within the biopsied tissues similar to the
results of Faulkerson et al (Clin Orthop 1985). The authors
reported a direct relationship between the severity of pain
and the severity of neural damage within the lateral
retinaculum; patients presenting with moderate to severe
complaints of pain were found to have the highest number of
nerves and neural area. These findings were further
supported in a follow-up study by Sanchis-Alfonso and
Rosello-Sastre (AJSM 2000). The authors repeated the prior
experiment, noting similar results with the additional finding
of increased levels of substance P within the lateral
retinaculum of patellofemoral patients.
Thus, it appears that the source of pain in patellofemoral patients is multifactoral, with the surrounding
soft tissues showing evidence of localized pain perception and neural adaptations that appear to
contribute to the source of patellofemoral pain.
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Chapter 3
Differential Diagnosis of Patellofemoral Pain
In 1998,one of the most influential rehabilitationpublications of the last 2 decadeswas published on
treatment of the patellofemoral joint. Four of the leaders
and pioneers of sports medicine and orthopedic
rehabilitation Kevin Wilk, George Davies, Bob Mangine,
and Terry Malone - teamed up to develop a classification
system for the differential diagnosis of patellofemoral
pathologies. This manuscript was the first to offer
treatment strategies based on specific diagnoses for
patellofemoral pain. Today, this manuscript still holds
extreme value and if you havent read it, I highlyrecommend finding a copy.
By far the most critical component of treating the
patellofemoral joint is an accurate diagnosis. I will always
challenge me students in this regard find the cause of
their symptoms and STOP using patellofemoral pain as a
diagnosis. At first this can seem like a daunting task as the
true source of patellofemoral pain can be misleading. However, using a classification system to group
types of diagnoses can be extremely helpful in the formation of your treatment program.
Classification of Patellofemoral Pain
Patellar Compression Syndromes
Patellar compressive syndromes are described as pathologies involving excessive compression between
the patella and the trochlea due to tight surround soft tissue. These can result in significant changes to
the articular surfaces of the patella and trochlea over time. This can be broken down into two distinct
types of compression syndromes:
Excessive lateral pressure syndrome (ELPS). ELPS was originally
described as occurring when the patella is overconstrained by soft
tissue tightness, specifically the lateral retinacular tissue. The
patient will exhibit a lateral tilted and/or shifted patella and
decreased medial glide. There is often times medial discomfort as
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the medial retinacular tissue is stretched due to a laterally displaced patella. I often find palpating the
medial patellofemoral ligament elicits a decent amount of discomfort. I believe proximal and distal
influences in the kinetic chain also effect the alignment of the patellofemoral joint and can cause an
ELPS-like syndrome, though through a different mechanism. This should be assessed and is discussed
more below.
Global patellar pressure syndrome (GPPS). GPPS occurs when
there is a general and diffuse medial and lateral soft tissue
tightness that results in the patella being excessively compressed
within the throclea. This is more commonly see after direct
trauma, immobilization due to fracture, or knee surgery with the
development of arthrofibrosis. Have you ever had a patient lose
patella mobility after an ACL reconstruction? This is a good
example of GPPS. These patients may also have decreased superior patellar mobility as the knee is
immobilized in flexion.
Patellar Instability
On the other side of the spectrum is patellar instability, which can
range from an acute dislocation to recurrent instability. On
examination, patients will have excessive patellar mobility laterally.
This is often associated with a shallow trochlea, so many patients
may be predisposed to this condition. I would suspect this with the
patient with chronic subluxations. Also, acute episodes of
subluxation or dislocation may result in rupture of the medial
patellofemoral ligament and subsequent medial pain. Patients with
chronic subluxation usually dont have as much sensitivity medially as
their tissue adapts and/or tears over time.
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Try this perform patellar gliding at 0 degrees of flexion and then again at ~30 degrees of flexion. If the
patella continues to have excessive gliding at 30 degrees, then they likely have a shallow trochlea and
poor static stability. These patients are challenging to treat as the static stability is a primary cause of
their symptoms.
Biomechanical Dysfunction
The knee appears to take a good amount of stress when biomechanical faults are present both
proximally and distally within the kinetic chain. Alterations in foot and ankle mechanics, hip strength,
leg length discrepancy, flexibility deficiencies, and any combination of these factors can have a negative
impact on the forces observed at the patellofemoral joint. Not only can biomechanical dysfunction lead
to increased stress, it can also lead to chronic adaptations over time. Take for example someone with
weak hip external rotation. This could lead to a dynamic inability to control the hip adduction and IR
moment at the knee and cause the femur to rotate into internal rotation during activities. This will
cause the patella shift laterally and can cause articular cartilage and soft tissue changes that will mimic a
typical ELPS patient. You can loosen up the lateral soft tissue but without treating the true cause, the
hip weakness, symptoms will continue to occur.
This will be discussed in greater detail in a later chapter as this is an important factor to consider.
Direct Patellar Trauma
This is my least favorite pathology as I seem to always be a victim of direct
patellar trauma myself. Have you ever hit your knee against a table leg?
Every time I do, and it seems frequent, I think of the acute trauma my
articular cartilage just took! This is also seen with patients falling on their
knee, which is common up here in the northeast during the winter when it
gets icy. Subjective exam should lead you this way, but you may have to
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probe, sometimes patients will forget that they fell 3 weeks ago or not correlate their symptoms with
the incident.
Patients in this classification can include bone bruises, articular cartilage lesions, and even fractures.
Soft Tissue Lesions
There are a few common soft tissue lesions that can occur to the patellofemoral joint. Accurate
diagnosis of these syndromes usually involves direct palpation to these areas and a certain mechanism
of trauma to the area.
Suprapatellar plica syndrome. The plica is an interesting and
debatable structure. I have always been of the belief that plica is very
individual and some people have larger synovial folds than others.
Most common is the suprapatellar plica, which is located medial and
superior to the patella. This structure gets tight against the femoral
condyle as the knee flexes so repetitive activities such as bike riding
can cause this.
IT band friction. Similarly, ITB friction can occur laterally as the
patellar tract of the IT band gets taught against the lateral femoral
condyle during flexion.
Fat pad syndrome. The fat pad of the knee is highly vascularized and
has rich nerve fibers. When a patients falls on their knee, they may
inflame this structure. You can easily palpate on either side of the
patellar tendon and find discomfort. Be sure to assure that you are
not palpating the patellar tendon as treatment for this will vary.
Medial patellofemoral ligament injury. This was previously discussed
above, but realize that any issues with chronic ELPS or patellar
instability will cause MPF ligament pathology.
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Overuse Syndromes
Overuse syndromes include patellar tendonitis and less commonly
quadriceps tendonitis superiorly. Patellar tendonitis most commonly
occurs at the inferior pole of the patella, but may also occur mid-tendon or at the tibial tuberosity. Patients will present with typical
symptoms of a tedonopathy.
Two types of apophysitis can occur in the knee. These are common in
adolescents during growth spurts and in athletes participating in
jumping sports. These can easily be palpated and may be seen Im
not a big fan of naming things after people as they dont offer any
description of what the pathology is so I will use two versions of the
terminology.
Traction apophysitis of the tibial tuberosity (Osgood-Schlatter).
Traction apophysitis of the inferior patellar pole (Sindig-Larsen-Johansson).
As you can see, there are many different pathologies that can occur to the patellofemoral joint. The
above list is not intended to be all-encompassing, but rather to create categories of diagnoses that share
similar treatment guidelines. There are other potential source of PF issues, including neurologic origins
from the lumbar spine or reflex sympathetic dystrophy, however I wanted to keep this discussion
orthopedic. Once I rule out orthopedic issues I will explore other origins and a likely referral back to the
doctor or specialist.
Next time a patient comes to you with a referral stating PFPS or anterior knee pain, I
challenge you to attempt to classify the patient appropriately. Treatments will vary greatly for
each diagnosis. These will be discussed in a future post.
Wilk KE, Davies GJ, Mangine RE, Malone TR. (1998). Patellofemoral disorders: a classification system and clinical guidelines for
nonoperative rehabilitation. JOSPT DOI:9809279
To vaguely classify each patient as patellofemoral pain
syndrome would be doing a disservice to the patient and will
likely not result in optimal outcomes. A clear and accurate
differential diagnosis is by far the most important aspect of
treatin the atellofemoral oint.
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Chapter 4
Principles of Patellofemoral Rehabilitation
Although the key to successful rehabilitation program for patellofemoral pain requires an accuratedifferential diagnosis, there are several principles to patellofemoral rehabilitation that should be
considered when designing any program. Below are what I would consider the 10 key principles of
patellofemoral rehabilitation. They can be used as a backbone to many programs and customized based
on the specific diagnosis.
1. Reduce Swelling
The first principle of patellofemoral rehabilitation is the reduction of swelling. Patellofemoral patients
often present with joint effusion following injury and postoperatively. Chronic edema may also exist due
to repetitive microtrauma of the soft tissues surrounding the patellofemoral joint.
Numerous authors have studied the effect of joint effusion on muscle inhibition. DeAndrade et al (JBJS
1965) were the first to report in the literature that joint distention resulted in quadriceps muscle
inhibition. A progressive decrease in quadriceps activity was noted as the knee exhibited increased
distention. Spencer et al (Archive Phys Med Rehab 1984) found a similar decrease in quadriceps
activation with joint effusion. The authors reported the threshold for inhibition of the vastus medialis to
be approximately 20-30ml of joint effusion and 50-60ml for the rectus femoris and vastus lateralis. This
is really not a lot of fluid, so any amount of effusion is significant. An unpublished study by Bob Mangine
in the 1990s showed that just a 30-40ml increase in fluid to the kneeresulted in almost a 50% drop in quadriceps peak torque.
The reduction in knee joint swelling is crucial to restore normal
quadriceps activity. Treatment options for swelling reduction include
cryotherapy, high-voltage stimulation, and joint compression through
the use of a knee sleeve or compression wrap. I personally really like
the Bauerfeind knee sleeves for knees that have some effusion. In
patients who have undergone a lateral retinacular release, a foam
wedge shaped to form around the lateral patella can be utilized in
conjunction with a wrap to provide patella medialization and increased
compression around the lateral genicular artery. I would not hesitate to
use a knee sleeve or compression wrap to apply constant pressure while
performing everyday activities in an attempt to minimize the
development of further effusion.
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2. Reduce Pain
The second principle of patellofemoral rehabilitation is the reduction of pain. Pain may also play a role in
the inhibition of muscle activity observed with joint effusion. Young et al (MSSE 1983) examined the
electromyographic activity of the quadriceps in the acutely swollen and painful knee. An afferent block
by local anesthesia was produced intraoperatively during medial meniscectomy. Patients in the controlgroup reported significant pain postoperatively and pronounced inhibition of the quadriceps (30-76%).
In contrast, patients with local anesthesia reported minimal pain and only mild quadriceps inhibition (5-
31%).
Pain can be reduced passively through the use of cryotherapy and analgesic medication. Immediately
following injury or surgery, the use of a commercial cold wrap, such as a DonJoy Iceman, can be
extremely beneficial. Passive range of motion may also provide neuromodulation of pain during acute
or exacerbated conditions. Various other therapeutic modalities such as ultrasound and electrical
stimulation may also be used to control pain via the gate control theory if that is your belief.
3. Restore Volitional Muscle Control
The next principle involves reestablishing voluntary control of
muscle activation. Inhibition of the quadriceps muscle is a
common clinical enigma in patellofemoral patients, especially in
the presence of pain and effusion during the acute phases of
rehabilitation immediately following injury or surgery. Electrical
muscle stimulation and biofeedback are often incorporated with
therapeutic exercises to facilitate the active contraction of the
quadriceps musculature.
Snyder-Mackler et al (JBJS 1991) examined the effect of
electrical stimulation on the quadriceps and musculature during
4 weeks of rehabilitation following ACL reconstruction. The
authors noted that the addition of neuromuscular electrical
stimulation to postoperative exercises resulted in stronger
quadriceps and more normal gait patterns than patients
exercising without electrical stimulation. Delitto et al (PT 1988)
and Snyder-Mackler et al (JBJS 1995) reported similar results ofboth the quadriceps and hamstrings using electrical stimulation for a 3-week and 4-week, respectively,
training period following ACL reconstruction.
The use of electrical stimulation and biofeedback on the quadriceps musculature appears to facilitate
the return of muscle activation and may be valuable additions to therapeutic exercises. Clinically, I use
electrical stimulation immediately following injury or surgery while performing isometric and isotonic
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exercises such as quadriceps sets, straight leg raises, hip adduction and abduction, and knee extensions.
I also use this as a maintenance program with many of my athletes with chronic knee issues.
4. Emphasize the Quadriceps
The next principle of patellofemoral rehabilitation is to strengthen the knee extensor musculature.
Some authors have recommended emphasis on enhancing the activation of the VMO in patellofemoral
patients based on reports of isolated VMO insufficiency and asynchronous neuromuscular timing
between the VMO and VL.
While the literature offers conflicting reports on selective recruitment and neuromuscular timing of the
vasti musculature, the VMO may have a greater biomechanical effect on medial stabilization of the
patella than knee extension due to the angle of pull of the muscle fibers at approximately 50-55
degrees. Wilk et al(JOSPT 1998) suggest that the VMO should only be emphasized if the angle of
insertion of the VMO on the patella is in a position
in which it may offer a certain degree of dynamic or
active lateral stabilization. As you can see by the
figure, if the fibers are not aligned in a position to
assist with patellar stabilization, VMO training will
likely not be effective. This orientation of the
muscle fibers will differ from patient to patient and
can be visualized.
Several interventions and exercise modifications
have been advocated to effectively increase theVMO:VL ratio, based mostly on anecdotal
observations. These include hip adduction, internal
tibial rotation, and patellar taping and bracing.
Powers(JOSPT 1998) reports that isolation of VMO
activation may not be possible during exercise,
stating that several studies have shown that
selective VMO function was not found during
quadriceps strengthening exercises, exercises
incorporating hip adduction, or exercises
incorporating internal tibial rotation. Powers alsostates that although the literature offers varying
support for VMO strengthening, successful clinical
results have been found while utilizing this treatment approach.
My belief is that quadriceps strengthening exercises should be incorporated into patellofemoral
rehabilitation programs. Strength deficits of the quadriceps may lead to altered biomechanical
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properties of the patellofemoral and tibiofemoral joints. Any change in quadriceps force on the patella
may modify the resultant force vector produced by the synergistic pull of the quadriceps and patellar
tendons, thus altering contact location and pressure distribution of joint forces. Furthermore, the
quadriceps musculature serves as a shock absorber during weightbearing and joint compression, any
abnormal deviations in quadriceps strength may result in further strain on the patellofemoral and/or
tibiofemoral joint.
In reality, I believe that quadriceps strengthening is very important for patellofemoral rehabilitation, but
many exercises designed to enhance VMO strength or activation may actually be disadvantageous to
the joint. Take for example the classic squeezing of the ball during closed kinetic chain exercises such as
squatting and leg press. This creates an IR and adduction moment at the hip that is now known to be
detrimental to patellofemoral patients. I would actually propose that we work on quadriceps
strengthening without an adduction component and rather emphasize hip adbuction and external
rotation. This can be performed with the use of a piece of exercise band around the patients knees
during these exercises. We will get into this in more detail in an upcoming post in this series.
5. Control the Knee Through the Hip
Again, I dont want to get to much into this as we will spend an
entire chapter on this topic, but the importance of hip strength
cannot be overlooked. Every patellofemoral patient should be
assessed for hip weakness and poor dynamic control of their knee
during functional activities. You will be shocked at how many of
your patients have absolutely no strength outside of the sagittal
plane. It is amazing.
Emphasize the hips ability to eccentrically control the valgus
moment at the knee produced by hip IR and adduction. I cant say
it enough, work on hip abduction and ER. This tip alone will
greatly enhance your patellofemoral outcomes. More on this in
an upcoming chapter.
6. Enhance Soft Tissue Flexibility
Another principle of patellofemoral rehabilitation is the enhancement of joint flexibility with emphasis
on quadriceps, hamstrings, hip adductors, gastrocnemius, and iliotibial band stretching. Any deficit in
flexibility of these areas will cause significant biomechanical faults throughout the kinetic chain.
Rehabilitation should focus on restoring full passive knee extension initially to minimize the
development of a flexed knee posture exhibited by some patients with patellofemoral disorders.
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Ambulating and performing daily activities with a knee flexion contracture may result in increased
patellofemoral joint reaction forces and requires a great deal of motor control to stabilize the knee joint.
Full passive knee extension is important for improved quadriceps activity and also allows the knee to
lock out while standing, thus allowing relaxation of the surrounding musculature.
Restoring full knee flexion is also a significant priority. In postoperative patients, knee flexion is graduallyrestored especially in the presence of an effusion. In non-operative patients, knee flexion is gradually
restored through controlled stretching exercises. The goal of restoring full knee flexion is not merely
reestablishing quadriceps flexibility but improving soft tissue flexibility of the retinacular tissues as well.
Witvrouw et al (AJSM 2000) prospectively studied the risk factors for the development of anterior knee
pain in the athletic population over a 2-year period. A significant difference was noted in the flexibility of
the quadriceps and gastrocnemius muscles between the group of subjects that developed
patellofemoral pain and the control group, suggesting that athletes exhibiting tight musculature may be
at risk for the development of patellofemoral disorders.
7. Improve Soft Tissue Mobility
Soft tissue mobility is another rehabilitation principle that must
be addressed. The goal of rehabilitation is to restore the soft
tissue flexibility of the medial and lateral retinacular and
capsular tissues. This may assist in controlling patellofemoral
joint reaction forces by balancing the soft tissue pliability
medially and laterally, and by correcting a possible tilt or
rotation of the patella. Additionally, patellar mobilizationtechniques should be utilized to restore superior and inferior
patellar mobility as well. Treatment techniques include patellar
mobilizations and the application of patellar tape.
While taping of the patella has received conflicting reports in
the literature regarding its efficacy for correcting biomechanical
deficits of the patella, taping may assist in restoring soft tissue
flexibility by providing a low-load prolonged stretch of the
retinacular tissues. Study after study shows that tape does not
impact patella position or tracking (dont get me wrong there
are some that show that it does, but there are more that says
tape does not). My personal belief is that this is the reason for
a reduction in symptoms with the application of tape.
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Remember that thesource of patellofemoral painmay not be from the articular cartilage but rather
from the retinacular tissue.
The utilization of a brace which imparts a medial glide or force to the patella may also be beneficial.
There are many on the market and I truly have no preference at this time. It seems like a new and
improved brace comes out every 6 months. Preliminary MRI studies have documented the effectivenessof bracing.
8. Enhance Proprioception and Neuromuscular Control
Rehabilitation programs must also include drills designed to restore proprioceptive and neuromuscular
control skills in patellofemoral patients. Proprioception and postural balance training begins
immediately postinjury or postoperatively. Specific drills initially include weight shifting side-to-side,
weight shifting diagonally, mini-squats, and mini-squats on an unstable surface such as a tilt board. As
the patient advances, tilt board squats can be progressed from double leg to single leg.
Perturbations can further be added to challenge the neuromuscular system. Initially, the clinician can
apply manual perturbations. As the patient sustains a vertical squat on a tilt board at 30 degrees of knee
flexion, the clinician adds perturbations by tapping the board with his or her foot.
Ball tosses can be incorporated with manual perturbations to provide additional challenge. The patient
progresses to perform a vertical squat to 30 degrees of knee flexion while performing a chest-pass with
a 3-5 pound weighted ball. The rehabilitation specialist continues to add manual perturbations by
tapping the board. Ball throws are progressed from chest-passes to side-to-side throws, and then
overhead soccer throws. Again, these exercises can be progressed from double-leg to single-leg stance
to further challenge the patients neuromuscular control.
Depending on their sport participation, jump and landing training may also be necessary to teach the
athlete how to avoid detrimental positions.
9. Normalize Gait
Gait training is also a critical component to patellofemoral
rehabilitation. A variety of factors contribute to antalgic and
inefficient gait patterns including joint effusion, pain, soft
tissue tightness, and scar tissue formation.
Strategies used to minimize the flexed knee gait pattern that is
commonly exhibited by patellofemoral patients include
minimizing joint effusion and enhancing sift tissue flexibility,
particularly the hamstring and gastrocnemius musculature.
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Specific techniques include retrograde walking over cones. This particular exercise requires adequate
quadriceps control and involves the patient ambulating while high stepping over successive cones. As
the patient moves backward, the foot strikes the ground in a toe to heel pattern to produce an
extension moment at the knee.
10. Gradually Progress Back to Activities
Lastly, as the patellofemoral patient progresses through the rehabilitation program, emphasis should
shift towards functional activities that replicate activities specific to each patient. The rate of
progression with functional activities is dictated by the patients unique tolerance to the activities.
Exercise must be performed at a tolerable level without overstressing the healing tissues. Pathological
loading that produces detrimental stress on the patellofemoral joint should be avoided to prevent
exacerbations of symptoms. Functional stresses are gradually increased leading to a steady return to
function. The functional progression of activities should follow a progressive and sequential order toensure proper amounts of stress are applied to facilitate healing without producing disadvantageous
forces.
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Chapter 5
Specific treatment guidelines for patellofemoral pain
Now that we have spent some time discussing thedifferential diagnosis of patellofemoral painand
principles of patellofemoral rehabilitation, we can move on to discussing specific treatment strategies
for each of the differential diagnoses we previously discussed. If you have not read chapter 3 of this
series on theclassification of patellofemoral pain, you may want to go back as the following
suggestions are based on that information.
Specific Treatment Based on an Accurate Diagnosis
Patellar Compression Syndromes
In general, the main goals of treating a patient with a compression syndrome is to loosen the restrictions
and minimize the subsequent inflammation. These are the patients that respond well to what I call a
loss of motion protocol:
Heat/whirlpool to warm up the tissue and prepare for treatment
Continuous ultrasound to tight area. We can argue about the efficacy of US but I think this is a
good time for its use. I am aggressive - continuous, jack it up to 2.0 and keep the area small, of course
use patient tolerance as a guideline!
Soft tissue massage progressing to aggressive massager or friction as inflammation subsides.
Specific trigger point and muscle energy techniques can be helpful as well, especially in the patient with
tight hips that are contributing to ELPS.
Remember, if you take one thing away from this eBook,
treatment should be based on an accurate diagnosis!
Diagnosing someone with patellofemoral pain syndrome is like
giving upand saying you dont know what is wrong with theatient!
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Patellofemoral joint mobilization in whatever direction
is needed
For a patient with ELPS, I would consider trying patellar
taping. I dont use this to really change the alignment or
biomechanics of the patellofemoral joint, study after studyshows this does not happen with tape. I do however believe
that the tape can be applied to potentially cause a low-load,
long-duration stretch of the soft tissue/retinaculum around
the knee. Remember, that stress and tension of the surround
tissue may be thecause of patellofemoral pain.
Generalized stretching of the lower extremity with
specific emphasis on tight structures impacting the PF joint
(i.e. the IT band).
As with anything else related to the patellofemoral joint, look
at the hip and foot to see if any biomechanical factors are contributing to lateral tightness of the knee.
There are also some things that should be avoidedin these patients:
Bike riding it is just going to compress the PJ joint and cause more symptoms
Exercises with high PF joint reaction forces, such as knee extension. Again, just going to cause
more compression and more irritation.
In the patient with global compression syndrome, I would recommend you avoid taping. Again, just
going to cause undue compression.
In general, I would be conservative in strengthening exercises for the global compression patient.
Straight leg raises, pool work, and other basic exercises should be enough while you loosen up the soft
tissue.
Patellar Instability
The treatment for patellar instability depends on the chronicity of symptoms. For acute episodes,
treatment will revolve around the damage control, or settling down the acute effusion and trauma
associated with the incident.
For the later phases of acute instability or those with chronic recurrent instability, we are basically
dealing with a lack of static stability from the osseous and ligamentous structures of the knee. Thus,
treatment should focus on enhancing stability in two ways:
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Enhance static stability. If this is an anatomical issue, this may be
difficult if not impossible. This is the perfect patient for a patellofemoral
brace. While a general donut knee sleeve or some of the older
patellofemoral braces may be enough for some patients, there are a lot of
newer and more advanced bracing. I have used the DonJoy Tru-Pull brace
with success. What types of braces have you tried and preferred?
Enhance dynamic stability. This is the general long term goal for these
patients. It starts with enhancing strength and progresses to
neuromuscular control exercises. This in itself is a lengthy topic, but I
recommend you check out a DVD of theprinciples of neuromuscular
control during knee treatmentthat Kevin Wilk and I have produced
(more information here from AdvancedCEU). This will include dynamic
stability of the entire lower extremity as any weakness in the kinetic chain
could cause an excessive lateral stress on the patellofemoral joint. More to
come on this in a future chapter in this eBook.
Biomechanical Dysfunction
As previously stated in my post on theclassification of patellofemoral
pain, the knee appears to take a good amount of stress when
biomechanical faults are present both proximally and distally within the
kinetic chain. Alterations in foot and ankle mechanics, hip strength, leg
length discrepancy, flexibility deficiencies, and any combination of thesefactors can have a negative impact on the forces observed at the
patellofemoral joint. Not only can biomechanical dysfunction lead to
increased stress, it can also lead to chronic adaptations over time. Take
for example someone with weak hip external rotation. This could lead to
a dynamic inability to control the hip adduction and IR moment at the
knee and cause the femur to rotate into internal rotation during
activities. This will cause the patella shift laterally and can cause
articular cartilage and soft tissue changes that will mimic a typical ELPS
patient. You can loosen up the lateral soft tissue but without treating
the true cause, the hip weakness, symptoms will continue to occur.
This will be discussed in greater detail in a future chapter in this eBook as this is an important factor to
consider.
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Direct Patellar Trauma
Ouch, I hate even thinking about direct patellar trauma. My knee hurts just thinking of it! With this
pathology, we are worried about either a patellar fracture or articular cartilage damage.
Once the initial trauma subsides, treatment should attempt to enhance cartilage healing. This means
frequent ROM of the knee. In addition to standard PROM, this can be in the form of a bike, if minimal
resistance is applied. You do not want to compress too much but a little bit of motion is better for
cartilage healing. I also like the pool for these patients if possible. Youll have to limit patellofemoral
joint reaction forces with exercises but this should subside with time.
If symptoms do not resolve, the patient should be sent back to their doctor for further evaluation to rule
out a fracture or an OCD type cartilage lesion.
Soft Tissue Lesions
Treatment of soft tissue lesions to the plica, IT band, fat pad, or medial patellofemoral ligament involves
an understanding of the basicprinciples of patellofemoral pain rehabilitation, but there are a few
things to consider as well. In general, you should stop the activity that is causing the irritation and avoid
direct pressure on that area, so no transverse friction massage initially. This may be appropriate when
chronic to stimulate healing, but in my experience this tends to make things worse for soft tissue
lesions. I have found that direct anti-inflammatory modalities, such as an iontopatch, is helpful for these
superficial areas of inflammation. Other treatment strategies for
specific lesions include:
Suprapatellar plica syndrome. The plica will get stressed over
the medial femoral condyle with knee flexion, so avoid activities
with repetitive flexion, such as bike riding and running.
IT band friction. Similarly to above but with the lateral femoral
condyle. Lengthening massage to the IT band has been helpful in
my practice.
Fat pad syndrome. The patient should avoid excessive
quadriceps activities, especially if this causes irritation to the fat pad
as the patellar tendon can compress the area when contracting the
quad.
Medial patellofemoral ligament injury. These patients should
actually have treatment similar to the ELPS patient above. A brace to control lateral patellar translation
may be helpful too.
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Overuse Syndromes
Overuse syndromes include tendonopathy to the patellar
tendon, and less commonly quadriceps tendonitis
superiorly, and apophysitis of the tibial tuberosity orinferior patellar pole.
For tendonopathy, treatment begins with assessing the
chronicity of symptoms. If acute, reduce inflammation
and restore strength and flexibility. I hate to be vague,
but I doubt youll see a lot of patients that are this acute.
Realistically, people put off treatment for months and
end up with chronic tendonosis. This is another lengthy
topic, but the key here is that the patellar tendon is not
actually inflamed, it is degenerative due to a lack of
healing blood supply (that is why the surgery for this is
debridement to stimulate healing). Thus, traditional
treatment to reduce inflammation is not going to work.
In a way, you need to induce a certain amount of trauma, such as with transverse friction massage. I
also recommend that general orthopedic patients need to feel about a 3-4/10 on a pain scale during
exercises to actually stimulate healing. Any less and you probably arent stressing the area enough and
any more and you may overloading.
Apophysitis of the tibial tuberosity or inferior patellar pole can be a pretty limiting pathology. The
two best treatments are time and avoiding the activity that causes symptoms. That means many youth
injuries will need to take some time off from basketball, or whatever may be causing their symptoms, as
their body grows and the symptoms resolve. Treatment is basically to reduce symptoms, there isnt
much you can do to actually heal the injury.
Now that we have discussed the basic principles of patellofemoral rehabilitation and some specific
treatment guidelines for various diagnoses, you should have a good basis to improve the care of your
patients. The principles discussed so far are extremely important to understand and apply to each
patient to assure you are optimizing your treatments and enhancing your outcomes. The next two
chapters in this eBook will take treatments one step further as we talk about the biomechanics of thepatellofemoral joint during exercises and the influence of the kinetic chain on the patellofemoral joint.
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Chapter 7
Biomechanics of the patellofemoral joint clinical implications
As we continue our journey through the diagnosis and treatment of patellofemoral injuries, it is time toshift gears from the basic principles of care and discuss our final two topics the biomechanics of the
patellofemoral joint itself and the biomechanical influence of the kinetic chain on the patellofemoral
joint. To me, these are two extremely important topics that are often not addressed as much as they
should.
Articulation of the Patellofemoral Joint
The patella really is an amazing bone in our body. Did you realize that the artiuclar cartilage on the
undersurface of the patella is the thickest in the body? That really is amazing and shows just how much
force is applied to the joint. Take a look at the picture on the right, notice how thick the cartilage is in
comparison to the bone?
When rehabilitating a patient with a known lesion of the patellofemoral joint, it its important tounderstand the joint arthrokinematics. Articulation between the inferior margin of the patella and the
femur begins at approximately 10 20 degrees of knee flexion. The patella does not articulate with the
trochlea near terminal knee extension. As the knee proceeds into greater degrees of knee flexion, the
contact area of the patellofemoral joint moves proximally along the patella and posterior along the
condyles.
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This is an important concept to understand and emphasizes the importance of good communication
between the physician and rehabilitation specialist. If we know the specific area of articulation, we can
work around that area, otherwise we dont know when a lesion will articulate and will have to be more
conservative.
Contact Area of the Patellofemoral Joint
In addition to understanding when the patellofemoral articulates, it is important to discuss the area of
contact. Obviously, contact between the patella and trochlea that covers a larger surface area will
distribute the load over a greater area. This is a driving factor in exercise selection and will be talked
about below. At 30 degrees, the area of patellofemoral contact is approximately 2.0cm2. The area of
contact gradually increases as the knee is flexed. At 90 degrees of knee flexion contact area triples,
increasing up to 6.0cm2. As you can see, The contact area initially is small and gradually increases as the
joint become more congruent.
Alterations in Q-angle are often associated with patellofemoral disorders and may alter the contact
areas and thus the amount of joint reaction forces of the patellofemoral joint.Huberti and Hayes
examined the in vitro patellofemoral contact pressures at various degrees of knee flexion from 20 120
degrees. Maximum contact area occurred at 90 degrees of knee flexion and was estimated to be 6.5
times body weight. A increase or
decrease in Q-angle of 10 degrees
resulted in increased maximum
contact pressure and a smaller
total area of contact throughout
the range of motion. This
information may be applied when
prescribing rehabilitation
interventions so that exercises are
performed in ranges of motion
that place minimal strain on
damaged structures.
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Patellofemoral Joint Reaction Forces
Patellofemoral joint reaction forces are observed during all movements of the knee. Often times, it is
the goal of rehabilitation to exercise the lower extremity while minimizing patellofemoral joint reaction
forces. Forces occur from a combination of:
Articulation and contact area
Resultant force vector between the quadriceps and patellar tendon
Muscle contraction
We have already discussed the articulation and contact area. Again, joint forces are reduced when
distributed over a large surface area. When we discuss lever arms, remember that the patellas true
function is to increase the mechanical advantage of the quadriceps muscle. Take a look at the diagram
below, notice how the resultant force (red arrow) vector increases as the knee flexes and the line of pull
from the quadriceps and patellar tendons causes a more compressive force?
I wish it were that simple and we could say that joint reaction forces are always highest as the knee
flexes. Unfortunately, we have to take muscle contraction into consideration as well. The quadriceps isdesigned to cause compression of the patellofemoral joint. The force of the quadriceps is greatest at
terminal knee extension, that is why patients with patellectomies have such a difficult time extending
their knees, they lost the biomechanical advantage of the patella and cannot produce enough
quadriceps force to fully extend the knee.
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Now put the contact area together with the quadriceps force. The quadriceps provides the greatest
compressive force near extension when the contact area of the patellofemoral joint is smallest. Thus, a
high force on a small area produces considerable patellofemoral joint reaction forces.
To demonstrate just how significant these forces are, take a look at the below table that I put together
from various sources for a 200 pound person. Notice how deep squatting applies close to 4000 lbs offorce to the patellofemoral joint (still want to squat?).
Activity Force % Body Weight Pounds of
Force
Walking 850 N 1/2 x BW 100 lbs
Bike 850 N 1/2 x BW 100 lbs
Stair Ascend 1500 N 3.3 x BW 660 lbs
Stair Descend 4000 N 5 x BW 1000 lbs
Jogging 5000 N 7 x BW 1400 lbs
Squatting 5000 N 7 x BW 1400 lbs
Deep Squatting 15000 N 20 x BW 4000 lbs
Biomechanics of Rehabilitation Exercises
The effectiveness and safety of open kinetic chain (OKC) and closed kinetic chain (CKC) exercises have
been heavily scrutinized in recent years. While CKC exercises replicate functional activities such as
ascending and descending stairs, OKC exercises are often desired for isolated muscle strengthening
when specific muscle weakness is present.
Steinkamp et alanalyzed the patellofemoral joint biomechanics during the leg press and extension
exercises in 20 normal subjects. Patellofemoral joint reaction force, stress, and moments were
calculated during both exercises. From 0 46 degrees of knee flexion, patellofemoral joint reaction
force was less during the CKC leg press. Conversely, from 50 90 degrees of knee flexion, joint reaction
forces were lower during the OKC knee extension exercise. Joint reaction forces were minimal at 90
degrees of knee flexion during the knee extension exercise.
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Escamilla et alobserved the patellofemoral compressive forces during OKC knee extension and CKC leg
press and vertical squat. Results were similar to the findings of Steinkamp et al; OKC knee extension
produced significantly greater forces at angles less than 57 degrees if knee flexion while both CKC
activities produced significantly greater forces at knee angles greater than 85 degrees.
When analyzing the biomechanics of the OKC knee extension, remember the concept from aboveregarding the quadriceps force near extension. Grood et alreported that quadriceps force was greatest
near full knee extension and increased with the addition of external loading. The small patellofemoral
contact area observed near full extension, as previously discussed, and the increased amount of
quadriceps force generated at these angles may make the patellofemoral more susceptible to injury. At
a lower range of motion, the large magnitude of quadriceps is focused onto a more condensed location
on the patella.
My friend Rafael Escamilla has published a few new studies on patellofemoral joint forces during the
lunge and squatting exercises. The first study, publishedin Clinical Biomechanics, demonstrated that
the front and side lunge exercises showed the same pattern of force as the squatting and leg press, with
more force the deeper the lunge. Interestingly, performing the lunge from a split-stance position (not
actually striding to perform the lunge) also showed a decrease in force and should be used initially. His
follow-up studydemonstrated that a longer stride has less force than a shorter stride during the forward
lunge.
Escamilla also analyzedthe patellofemoral joint reaction forces between the wall squat (performed with
feet close to wall and far away from wall) and the single leg squat. Results indicate that the closer your
feet are to the wall, the greater the force during the wall squat exercise. At deeper angles > 60 degrees,
the wall squat produced greater force than the one legged squat. Interesting results that should be
applied to our exercise prescription.
Clinical Implications
When applying the results of Steinkamp(38), Escamilla(39), and Grood(40), it appears that during OKC
knee extension, as the contact area of the patellofemoral joint decreases the force of quadriceps pull
subsequently increases, resulting in a large magnitude of patellofemoral contact stress being applied to
a focal point on the patella. In contrast, during CKC exercises, the quadriceps force increases as the knee
continues into flexion. However, the area of patellofemoral contact also increases as the knee flexes
leading to a wider dissipation of contact stress over a larger surface area.
Recently, Witvrouw et al (41) prospectively studied the efficacy of open and closed kinetic chain
exercises during non-operative patellofemoral rehabilitation. 60 patients were participated in a 5-week
exercise program consisting of either open or closed kinetic chain exercises. Subjective pain scores,
functional ability, quadriceps and hamstring peak torque, and hamstring, quadriceps, and gastrocnemius
flexibility were all recorded prior to and following rehabilitation as well as at 3 months proceeding. Both
http://www.ncbi.nlm.nih.gov/pubmed/9565938?ordinalpos=25&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/9565938?ordinalpos=25&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/6725319?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/6725319?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/18632195?ordinalpos=6&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/18632195?ordinalpos=6&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/18632195?ordinalpos=6&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/18978453?ordinalpos=5&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/18978453?ordinalpos=5&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/19276845?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/19276845?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/19276845?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/18978453?ordinalpos=5&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/18632195?ordinalpos=6&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/6725319?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/9565938?ordinalpos=25&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum8/3/2019 Mike Reinold - Solving the PF Mystery
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treatment groups reported a significant decrease in pain, increase in muscle strength, and increase in
functional performance at 3 months following intervention.
Thus it appears that the use of both open and closed kinetic chain exercises may be used to maximize
outcomes for patellofemoral patients if performed within a safe range of motion. I prescribe the form of
exercise based on the clinical assessment. If CKC exercises are less painful than OKC exercises, than thatform of muscular training is encouraged. Additionally, in postoperative patients, regions of articular
cartilage wear is carefully considered before an exercise program is designed. Most frequently, Ill allow
open kinetic exercises such as knee extension from 90 40 degrees of knee flexion. This range of motion
provides the lowest amount patellofemoral joint reaction forces while exhibiting the greatest amount of
patellofemoral contact area. Closed kinetic chain exercises such as the leg press, vertical squats, lateral
step-ups, and wall squats (slides) are performed initially from 0 to 30 degrees and then progressed to 0
to 60 degrees where patellofemoral joint reaction forces are lowered. As patient symptoms subside, the
ranges of motion that are performed are progressed to allow greater muscle strengthening in larger
ranges. Exercises are progressed based on the patients subjective reports of symptoms and the clinical
assessment of swelling, painful crepitus, and discomfort.
I really enjoy digging deep into the biomechanical factors involved with rehabilitation. You may want to
check out the webinar that I did on the biomechanical implications of patellofemoral rehabilitation. It
discusses a lot of this chapter plus much more included better visualizations and clinical implications for
rehabilitation.
Click here for more information or visit AdvancedCEU.com
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Chapter 7
Understanding the clinical implications of the kinetic chain: The influence of
the hip and foot on the patellofemoral joint
The influence of the kinetic chain on the patellofemoral can not be underestimated. Because the knee is
located mid-way through a weightbearing extremity, it is
vulnerable to excessive force from biomechanical faults
located both proximally and distally to the knee itself.
While forces from the foot and ankle have been
associated with patellofemoral pain for some time now,
the influence of the hip is becoming more of a hot topic
as research has demonstrated significant increases in
forces and injuries originating from biomechanical faultsassociated with the hip. A particular pioneer in this research has beenDr. Christopher Powers from the
University of Southern California. A Pubmed search on Dr. Powers reveals several significant papers on
the topic, specificallyone of my favorites from JOSPTon the influence of the kinetic chain on
patellofemoral biomechanics.
I believe a significant reason why patellofemoral pain has been such a challenging diagnosis in the past
is because we are treating the symptoms, not the cause of the pain, which is many times may be coming
from elsewhere within the kinetic chain.
The Influence of the Hip on Patellofemoral Pain
The influence of the hip on the patellofemoral joint has been well documented over the last decade.
The biomechanical works of Dr. Powers have shown that excessive hip adduction and internal rotation
places the patellofemoral joint in a disadvantageous position.
Unfortunately, our population is dominated by sagittal plane strength and weakness in the coronal and
transverse planes. It seems like it is a normal part of daily living now as the majority of our functional
tasks take place in the sagittal plane. Even more unfortunate is the fact that exercises outside of the
sagittal plane are often neglectedin rehabilitation and strength training programs. This creates a
significant biomechanical disadvantage.
To fully understand the significance of this, imaging the weightbearing knee. When the hip moves into
adduction and internal rotation while the foot is planted, the femur will change position around a
relatively stable patella (there is movement, just using this as an example). It is the reverse concept that
Remember:
Examination of the joints proximal and
distal to the knee is imperative in the
treatment of patellofemoral pain.
http://pt.usc.edu/sublayout.aspx?id=346http://pt.usc.edu/sublayout.aspx?id=346http://pt.usc.edu/sublayout.aspx?id=346http://pt.usc.edu/sublayout.aspx?id=346http://www.ncbi.nlm.nih.gov/pubmed/14669959?ordinalpos=45&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/14669959?ordinalpos=45&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/14669959?ordinalpos=45&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/14669959?ordinalpos=45&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://pt.usc.edu/sublayout.aspx?id=346http://pt.usc.edu/sublayout.aspx?id=346http://pt.usc.edu/sublayout.aspx?id=3468/3/2019 Mike Reinold - Solving the PF Mystery
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is commonly seen in patellofemoral rehabilitation. The movement, or tracking of the patella on the
femur is less relevant in this weightbearing position. It is the movement of the femur on the patella that
is significant. Below is an example of how the femurs moves on the patella in the weightbearing
position, note the patella is fairly stable while the femur rotates internally:
This is likely the mechanism of patellar subluxations and dislocations and the cause of wear and tear of
the joint. Patients often describe an injury that occurs when planting and pivoting or planting on an
unstable surface. The quadriceps contracts to stabilize the knee while the femur is adducted and
internally rotated, resulted in a lateral displacement of the patella in relation to the femur. This can
cause an acute injury as well as degeneration over time.
A recent study byDr. Powers in JOSPTshowed that females with patellofemoral pain had greater hip
rotation during running, jumping, and stepping down. This also leadto subsequent decrease in hip strength. In fact, another study byDr.
Powers group published in AJSMdemonstrated that patellofemoral
pain in women is the results of decreased hip strength not anatomical
variations (wider hips, etc.).
Treatment of these patients requires training the hip to abduct and
externally rotate. Also, it is important to train the hip abductors and
external rotators to isometrically stabilize the knee during sagittal
plane movements and to eccentrically control hip adduction and
internal rotation. A simple test I perform is the step-down exercise. Iam specifically looking for the ability to eccentrically lower the body
in the sagittal plane while preventing the hip from dipping into
adduction and internal rotation. This is harder than it looks and will
often be an issue in your patients. But trust me, overtime this will
improve, and POOF! Your patients patellofemoral pain while
climbing stairs and running will have vanished! You are a genius now,
http://www.ncbi.nlm.nih.gov/pubmed/19131677?ordinalpos=12&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/19131677?ordinalpos=12&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/19131677?ordinalpos=12&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSumhttp://www.ncbi.nlm.nih.gov/pubmed/19098153?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmedhttp://www.ncbi.nlm.nih.gov/pubmed/19098153?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmedhttp://www.ncbi.nlm.nih.gov/pubmed/19098153?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmedhttp://www.ncbi.nlm.nih.gov/pubmed/19098153?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmedhttp://www.ncbi.nlm.nih.gov/pubmed/19098153?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmedhttp://lh4.ggpht.com/_BsgqbRhgCnQ/SkjE98HUVzI/AAAAAAAAAmc/r9TUmg9FwOk/s1600-h/image32.pnghttp://lh4.ggpht.com/_BsgqbRhgCnQ/SkjE98HUVzI/AAAAAAAAAmc/r9TUmg9FwOk/s1600-h/image32.pnghttp://lh4.ggpht.com/_BsgqbRhgCnQ/SkjE98HUVzI/AAAAAAAAAmc/r9TUmg9FwOk/s1600-h/image32.pnghttp://lh4.ggpht.com/_BsgqbRhgCnQ/SkjE98HUVzI/AAAAAAAAAmc/r9TUmg9FwOk/s1600-h/image32.pnghttp://www.ncbi.nlm.nih.gov/pubmed/19098153?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmedhttp://www.ncbi.nlm.nih.gov/pubmed/19098153?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmedhttp://www.ncbi.nlm.nih.gov/pubmed/19098153?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmedhttp://www.ncbi.nlm.nih.gov/pubmed/19131677?ordinalpos=12&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum8/3/2019 Mike Reinold - Solving the PF Mystery
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the last three times she went to rehabilitation elsewhere they perform ultrasound on her knee and had
her squeeze a ball between her knees during mini-squats to strengthen her VMO.
Which brings up a great topic, do you still want to squeeze that ball between your knees and emphasize
hip adduction and internal rotation? I would actually recommend just the opposite. I frequently use a
piece of Theraband (or even those new knee resistance straps that Theraband just started making)around the patients knees during exercise. This will require the patient to isometrically control the hip
from adducting and internally rotating while performing mini-squats, wall squats, leg press, and other
sagittal plane exercises
The Influence of the Foot and Ankle of Patellofemoral Pain
Just as forces located proximal to the knee can have a significant impact on the patellofemoral joint,
forces distal to the knee may also contribute. Treatment for patellofemoral patients should include a
thorough assessment of the foot and ankle to establish biomechanical factors that need to be
addressed. Orthotic fabrication is often necessary, though off-the-shelf orthotics have had some
success in the literature.
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Pronation. Excessive pronation of the foot causes a reciprocal internal rotation moment of the tibia.
This turn increases the resultant Q-angle at the knee. As we previously discussed in our previous post
on thebiomechanics of the patellofemoral joint, an increased Q-angle will cause a greater amount of
force on a more focal portion of the patella. Furthermore, an internal rotation moment of the tibia also
results in internal rotation of the femur and a more laterally displaced patella. This may be a cause of
ELPS as discussed previously when we discussed
thedifferential diagnosis of patellofemoral pain.
Leg Length Discrepancy. I chose to include leg
length discrepancy with the group of distal forces
as the impact of a longer leg length tends to impact
the positioning of the foot and ankle. The longer
leg will tend to have a toe-out and pronated
position to compensate for the longer length.
Supination. Patients labeled as pronators seem
to get all the attention, but excessive supination is
likely just as bad. Not only do you diminish the
foots ability to dissipate force, supination will
result in external rotation of the tibia and more
force to the patella.
You can see that the position of the foot and ankle when the foot hits the ground is important to
evaluate as it will alter the arthrokinematics and patellofemoral joint reaction forces.
It can not be stressed enough that it is imperative that the proximal and distal aspects of the kinetic
chain need to be evaluated and treated in patients with patellofemoral pain. I am sure that youroutcomes will begin to improve by not neglecting this important aspect of treatment.
Powers CM (2003). The Influence of Altered Lower-Extremity Kinematics on Patellofemoral Joint Dysfunction: A Theoretical Perspective J Orthop Sports
Phys Ther DOI: 14669959
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Chapter 8
Have We Solved the Patellofemoral Mystery?
Probably not, but although the patellofemoral joint may still be a complicated area of sports medicine, Ihope that this eBook has helped take the some of the mystery out of patellofemoral pain. In putting the
pieces of this series together, remember to:
Understand the source of patellofemoral pain and realize it might not be from
chondromalacia.
Perform a thorough examination and attempt to identify a specific diagnosis, lets stop using
the term patellofemoral pain and describe the actual diagnosis!
Consider the basic principles of patellofemoral pain rehabilitation, including understanding
the biomechanics of the joint and the biomechanics during exercise.
Look proximal and distal within the kinetic chain to identify a potential true source ofpatellofemoral pain and stop treating the symptoms!
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