Mike Reinold - Solving the PF Mystery

8/3/2019 Mike Reinold - Solving the PF Mystery

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MikeReinold.com - Page 1

Michael M. Reinold, PT, DPT, SCS, ATC, CSCS

MikeReinold.com


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Solving the Patellofemoral Mystery


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
http://mikereinold.com/http://mikereinold.com/


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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,


Welcome to my new

eBook dedicated to evaluating

and treating the patellofemoral

joint.



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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.
http://astore.amazon.com/mikereicom-20/detail/0781740819http://astore.amazon.com/mikereicom-20/detail/0781740819http://astore.amazon.com/mikereicom-20/detail/0781740819http://astore.amazon.com/mikereicom-20/detail/0781740819http://astore.amazon.com/mikereicom-20/detail/0781740819


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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
http://www.ncbi.nlm.nih.gov/pubmed/9809279?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVLinkOuthttp://www.ncbi.nlm.nih.gov/pubmed/9809279?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVLinkOuthttp://www.ncbi.nlm.nih.gov/pubmed/9809279?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVLinkOuthttp://www.ncbi.nlm.nih.gov/pubmed/9809279?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVLinkOuthttp://lh6.ggpht.com/_BsgqbRhgCnQ/Sg4lnJojl4I/AAAAAAAAAgw/bt-dninmFN0/s1600-h/image7.pnghttp://www.ncbi.nlm.nih.gov/pubmed/9809279?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVLinkOuthttp://www.ncbi.nlm.nih.gov/pubmed/9809279?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVLinkOut


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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.
http://dx.doi.org/9809279http://dx.doi.org/9809279http://dx.doi.org/9809279http://dx.doi.org/9809279


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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_RVDocSum


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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
http://www.advancedceu.com/Webinars.htmlhttp://www.advancedceu.com/Webinars.htmlhttp://www.advancedceu.com/Webinars.html


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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.
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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_RVDocSum


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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
http://www.mikereinold.com/2009/06/biomechanics-of-patellofemoral.htmlhttp://www.mikereinold.com/2009/06/biomechanics-of-patellofemoral.htmlhttp://www.mikereinold.com/2009/06/biomechanics-of-patellofemoral.htmlhttp://www.mikereinold.com/2009/05/classification-of-patellofemoral-pain.htmlhttp://www.mikereinold.com/2009/05/classification-of-patellofemoral-pain.htmlhttp://www.mikereinold.com/2009/05/classification-of-patellofemoral-pain.htmlhttp://dx.doi.org/14669959http://dx.doi.org/14669959http://dx.doi.org/14669959http://dx.doi.org/14669959http://www.mikereinold.com/2009/05/classification-of-patellofemoral-pain.htmlhttp://www.mikereinold.com/2009/06/biomechanics-of-patellofemoral.html


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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!

Mike Reinold - Solving the PF Mystery

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Transcript of Mike Reinold - Solving the PF Mystery