16 - Control Muscular de La Patela

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Muscular control of the patella

Terry Malone, EdD, PT, ATCa,*,George Davies, MEd, PT, ATCb, W. Michael Walsh, MDc

aDepartment of Physical Therapy, University of Kentucky, 900 South Limestone,

Lexington, KY 40536, USAbDepartment of Physical Therapy, University of Wisconsin LaCrosse, LaCrosse, WI 54601, USAcDepartment of Orthopaedics, University of Nebraska Medical Center, Omaha, NE 68118, USA

Although a commonly discussed subject, more misinformation and anecdotal

presentations may exist for muscular strengthening and patellar control than in

nearly any other area of knee rehabilitation. Much of this is the result of the

slow development of appropriate analyses of clinical efficacy in orthopedic

rehabilitation (ie, few published significant clinical outcome studies related to

these patients) but most importantly is related to the complex nature of thepatellofemoral joint and its impact on function. Since the 1950s, generations of

clinicians have been imbued with the concept that knee rehabilitation requires

an emphasis on vastus medialis obliquus strengthening. Some of the early

classic works included sage observations but have been interpreted in a manner

that has led to long lasting misinformation. An interesting example is the work

of Smillie (1962):

The extensor apparatus may be regarded as consisting of two components, the

rectus femoris, vastus lateralis and vastus intermedius, which extend the knee to

within 10 15 degrees of full extension, and the vastus medialis which isselective in action and comes into force in producing the last 1015 degrees of

extension, although it may be used throughout the whole range in overcoming

marked resistance [1].

He also labeled the vastus medialis the key to the knee and espoused it is

the vastus medialis which is almost entirely responsible for the stabilization and

protection of the joint from injury [1].

Lieb and Perry addressed these major points in their anatomic/mechanical

analysis in 1968 [2]. They determined that some of these observations are

related to the thin fascial covering of the vastus medialis, the orientation oflongitudinal and oblique fibers in the medialis, the independent innervation of

0278-5919/02/$ see front matterD 2002, Elsevier Science (USA). All rights reserved.

PII: S 0 2 7 8 - 5 9 1 9 ( 0 2 ) 0 0 0 1 4 - 5

* Corresponding author.

E-mail address:[email protected] (T. Malone).

Clin Sports Med 21 (2002) 349362


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the medialis oblique fibers, and the function of the oblique fibers to align the

patella in the last 10to 15of extension. Most importantly in their conclusions

and summary they delineated that the early atrophy of the medialis indicates thegeneral quadriceps rather than that of a local medialis deficiency and that the

only selective function of the medialis is patellar alignment. Again, the unfor-

tunate interpretation of their work was that terminal extension (the 10 to 15

range of motion) would therefore provide a selective training impetus for the

vastus medialisparticularly the oblique fibers responsible for patellar align-

ment. Fig. 1 presents the generally accepted vasti muscular orientation and

insertional pattern.

Since 1968, many clinicians have invoked the Lieb and Perry article as

being supportive of selective recruitment and exercise. The term VMO (vastusmedialis obliquus) strengthening or emphasis has become synonymous with

patellofemoral exercise prescription. This article is designed to provide the reader

a review of what the peer reviewed literature supports and refutes related to

muscular control of the patella. Statements or concepts will be presented and

discussed in this format.

Muscular innervationneuromuscular drive

The evolution of surface and indwelling electromyography (EMG) has been

vital to our appreciation of muscle function. Computer analyses have dramat-

ically enhanced our ability to interpret and examine quadriceps femoris function.

Where previously raw electrical signals were examined, envelops of potentials

are now rectified, integrated (area under the curve), and manipulated to provide

better recognition and representation of muscle function. Most investigators will

use amplitude as their measured value of muscular output in relation to

demanded action.

It is important to recognize limitations as well as the great value of EMG. Wecan reliably assess muscle onset and cessation of action but must be cautious in

the use/interpretation of amplitude, as reliability is often somewhat inconsistent,

particularly values within an individual often demonstrating significant variation.

Thus, several areas of these analyses deserve comment.

Selective action of the vastus medialis obliquus in terminal extension

As described previously, several investigators provided clinical observationsof what appeared to be direct evidence of the VMO being most active in terminal

extension. The early EMG study of this phenomenon (1971) was again by Lieb

and Perry [3] that refuted these claims. They evaluated the EMG of the

quadriceps (including the VMO) at several positions during maximal isometric

contractions. Using a pattern of correlation between torque/position/EMG ampli-

tude, the quadriceps (including the VMO) was seen to exhibit a stable, consistent

T. Malone et al / Clin Sports Med 21 (2002) 349362350


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Fig. 1. Insertional patterns of the quadriceps femoris (VASTI: VM, vastus medialis; VMO, vastus medialis o


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pattern of recruitment throughout the range of motion with the VMO having the

highest values. Again, this has often been misinterpreted by some as supporting

terminal extension as the exercise of choice for patellofemoral patients.Brownstein et al [4] used a similar methodology to determine the optimal level

of EMG in relationship to torque of the quadriceps. These researchers reported

that peak integrated EMG occurred at approximately 50 for males and 70 for

females during maximal isometric muscle activation. VMO activation was not

maximal in extension but rather lower in the range of motion corresponding to

maximal torque. This is in agreement with Knight et al [5] who showed a

decrease of vastus medialis activity occurred as one moved into extension from a

flexed position. These data support the use of exercise lower in the range of

motion (90

to 60

or 45

) as being more likely to maximally recruit the vastusmedialis (longitudinal and oblique fibers) than terminal extension activities.

It seems that terminal extension is not able to isolate the VMO from the other

quadriceps muscular elements. The clinical observations indicate VMO atrophy

that represents the quadriceps as a whole. Because of the superficial location and

thin fascial covering, the VMO is much more easily palpated and observed.

Terminal extension provides a biomechanically disadvantaged position for the

quadriceps mechanism thus requiring high activity of the muscles in extension

but not in an isolated fashion.

It is our recommendation to view the VMO as the mirror of the quadriceps. Awell-defined VMO represents a strong extensor mechanism. Palpation of a tensed

VMO also enables an estimation of function as the involved extremity nearly

always exhibits a softness or less rigid muscle belly than the maximally tensed

uninvolved extremity.

Isolation of the VMO by way of specific exercise

Numerous investigators have recommended a specific position or pattern of

exercise to selectively challenge the VMO. One of the most commonly cited is theconcept of incorporating hip adduction into the quadriceps-strengthening program.

Hanten and Schulthies [6] examined the effect of maximal isometric contrac-

tions of internal tibial rotation and hip adduction on EMG in the VMO and vastus

lateralis (VL). The EMG amplitude was then normalized by way of comparison

to the maximal voluntary contraction (MVC) values seen during knee extension.

Hip adduction resulted in VMO values that were 61.75% of the MVC during

extension, statistically greater than those seen in the VL (45.63%). There were no

differences in VMO/VL during internal tibial rotation (47% and 45%). This led

these investigators to conclude that the VMO may be selectively strengthenedthrough hip adduction. It must be noted that the authors were speaking of hip

adduction and its resultant overflow creating activity in the VMO (approximately

60% of what one produces with extension).

Others have attempted to incorporate hip adduction with knee extension as a

selective means of training. Andriacchi et al used this combination with dynamic

submaximal efforts that actually demonstrated decreased VMO and VL EMG



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than seen in corresponding static isometric positions of knee extension [7]. Karst

and Jewett [8] asked their subjects to perform a series of quadriceps exercises:

quadriceps setting (QS), straight leg raising (SLR), SLR with hip lateral rotation,and SLR with hip adduction. The greatest quadriceps EMG was seen during QS

and none of the variations provided additional emphasis to the medial/medialis

vasti. Gryzlo et al analyzed five commonly used patellofemoral exercises (SLR,

short arc extension, short arc extension with hamstring cocontraction, squat, and

isometric co-contraction quadriceps/hamstrings) through EMG activity [9]. No

selective actions were seen but increased activity in both (simultaneously) the

medial and lateral vasti was seen in certain positions or actions. Laprade et al

used subjects with and without patellofemoral pain comparing their respective

EMG activity during five isometric exercises [10]. These exercises included kneeextension, hip adduction, adduction with knee extension, internal tibial rotation,

and knee extension with internal tibial rotation. Extension exercises had the

greatest EMG values, no biasing (selective action or demand) of/to the medial

vasti was seen, and no significant patterns of difference (VMO/VL) were seen

between patients and controls. Only 13% of VMO EMG seen in this submaximal

knee extension action was generated during hip adduction, significantly less than

described by the maximal effort study of Hanten and Schulthies.

Mirzabeigi et al examined nine quadriceps-strengthening exercises to deter-

mine if an isolation or emphasis to the VMO could be created [11]. Theseexercises included maximal isometric knee extension (hip neutral, 30 internal

rotation, and 30external rotation); maximal isokinetic knee extension (full range

and terminal 30range of motion); sidelying ipsilateral and contralateral full knee

extension with a 10-pound weight; and stand and jump from a full squat.

Normalized EMG analysis was performed for the VMO, VM, vastus intermedius,

and vastus lateralis through indwelling fine wire. Their results showed high-

integrated EMG amplitude for the medial and lateral portions of the vasti during

specific actions but no selective opportunities for the VMO.

The literature thus does not support that isolated VMO exercises exist.Although adduction of the hip shows overflow to the VMO, it is not sufficient

to provide a strong training level stimulus (greater than 70% of MVC) to this

structure. The VMO and VL are highly active in terminal range of extension.

Most of these exercises have been imbedded in rehabilitation regimens that

have been successful in their overall goal of enabling patellofemoral patients to

return to function following a six to eight week training program. Nonsurgical

care has been effective in our clinical experience in approximately 8085% of

patients presenting with patellofemoral symptoms. Because of this, many of the

purported successes may not be because of the specific concept but rather tothe general improvement of the quadriceps as a whole.

Timing of muscle activation

Several investigators have espoused that there is an alteration of activation

among the components of the quadriceps in patients with patellofemoral pain.

T. Malone et al / Clin Sports Med 21 (2002) 349362 353


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The implication has been that patients have an altered pattern whereby the VMO

is not activated early enough to avoid the lateralization of the patella.

Souza and Gross [12] compared the VMO/VL EMG ratio of controls andpatients with patellofemoral pain during isotonic and isometric conditions. Stair

climbing (isotonic) provided a greater ratio than isometric actions and patients

VMO/VL ratios were lower than ratios among control subjects. They concluded

that patients with patellofemoral pain may have abnormal VMO/VL activation

patterns, and speculated that isotonic patterns of exercise may be more beneficial

than isometric actions.

Voight and Wieder evaluated the reflex response time in the VL and VMO to a

patellar tendon tap [13]. They recruited 41 control subjects and 16 patients with

anterior knee pain and evaluated the reflex latency of the VMO and VL. Theirdata demonstrated that control subjects fired their VMO before the VL, whereas

patients exhibited a reversal of this pattern. They concluded that patellofemoral

pain patients might demonstrate a neurophysiologic motor control imbalance.

Karst and Willett [14] examined the timing of reflex responses of the

quadriceps much like the previous study. EMG signals were recorded following

patellar tendon tap but also in active knee extension in weightbearing and

nonweightbearing positions. There were no significant EMG response differences

for controls versus patients in any of the conditions. These authors explained how

their study differed from the previous study through their use of normalizingresponses related to subject height and other problems perceived with the

relevancy of the previous data. One additional important finding was the lack

of difference during active exercise. The authors pointed out that reflex patterns

might not reflect the active unit.

Powers et al [15] examined the timing and intensity of the vasti EMG activity

during level walking, stair climbing, and walking on ramps. Twenty-six patello-

femoral pain patients and 19 normal control subjects were assessed by way of

fine wire EMG while knee motion was recorded through a motion analysis

system. No differences in the onset or cessation (timing) of muscle activity wereseen; patellofemoral pain patients often exhibited decreased overall EMG

intensity. There were no selective VMO differences compared with VL activity.

It seems that there are no significant differences in timing or VMO/VL

amplitude ratio during active exercise. The early study results supporting differ-

ences has not been duplicated by later investigators.

Although patellofemoral rehabilitation regimens incorporate a variety of

exercises, using those that generate the best responses for each individual

afflicted with patellofemoral pain presents a great challenge for the clinician

and patient. We recommend a process of matching the exercise pattern to the typeof primary problem (classification) with which the patient presents.

What is the impact of pain in the patellofemoral patient?

The classic pattern of pain and effusion resulting in inhibition is vividly

displayed at the patellofemoral joint in relationship to quadriceps activation. The



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work of deAndrade et al linked knee joint distension with significant reflex

inhibition of the quadriceps [16]. It is obvious that pain is similar in effect when

inhibition is observed as demonstrated by Miller et al who found increased VMOEMG through decreased pain measures [17]. Spencer et al provided data

supporting an early response to effusion in the VMO as EMG changes were

seen with 2030 ml of effusion whereas 5060 ml were required to have a

similar effect on the VL [18].

Boucher et al examined the vasti muscle activity in subjects with patellofe-

moral pain [19]. These investigators included Q-angle assessment to enable a

correlation between this and pain, strength, and EMG activity. When they

compared the EMG of the VMO/VL ratio in the five patients with the highest

Q-angles to control subjects, a significant difference was seen at the terminal 15

of extension. This was only in the symptomatic group and was demonstrated only

near extension, as the ratio was not different lower in the range of motion. This

finding is in agreement with Sousa and Gross [12] who found a decrease in

VMO/VL ratio as one moves into extension with patellofemoral pain patients.

Cerny [20] collected IEMG from a series of patellofemoral patients and

controls using a variety of exercise patterns examining the VMO/VL ratio and

pain perception. Although the patients reported a significant decrease in pain by

way of taping during exercise, no alteration was seen in the VMO/VL EMG ratio.

Conway et al [21] documented a similar outcome in patients with anteriorknee pain. These subjects were tested on an isokinetic device concentrically and

eccentrically with significant decreases in pain perception seen during exercise

when modifiers (tape or brace) were used. An increase in strength was seen in the

taped and braced conditions but the increase was not correlated with the level of

pain decrease.

The literature supports the concept of significant inhibition being present with

pain and effusion. Treatments to reduce pain and swelling result in enhanced

strength measurements but no variation of the VMO/VL ratio (no selective

effect). There is some support for a smaller level of effusion affecting the VMOwhile not having an equal effect on the VL.

The rehabilitation regimen must include pain modulation facilitating pain-free

exercises, a requirement for normal recruitment of the vasti. Without such,

normal neuromuscular patterns are not developed (or redeveloped) and long-

term abnormal patterns may be reinforced. A variety of techniques can be used as

outlined in an earlier article in this volume.

What are the effects of taping, foot orthotics, and bracing on the patellofemoral

joint patient?

Jenny McConnell popularized the use of taping the patella to enhance the

patients ability to perform pain-free exercises [22]. The clinician evaluates the

patient related to a variety structures and typically uses tape to place a medial pull

on the patella. Rotation and tilt of the patella are also assessed/addressed. This

activity is then evaluated by comparing the level of pain perceived while



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performing a step up-step down with the untaped condition. McConnell indicates

that this process provides a true long-term solution for these patients [22].

Gilleard et al followed these concepts and evaluated the effects of taping onthe onset of VMO and VL muscle activity in subjects with patellofemoral pain

[23]. Comparison of untaped and taped conditions showed there was no

difference in onset times among untapped subjects, whereas the VMO onset

was earlier in the taped condition during step up and step down tasks. The

investigators indicated the earlier onset of the VMO may be helpful in patellar

control. Further research is needed to determine if it effects patellar position and

if this is beneficial.

Conway et al [21] evaluated a series of 30 patellofemoral pain patients related

to the impact of patellar taping on pain perception and quadriceps eccentric/concentric output. Taping provided a significant increase in eccentric and

concentric outputs compared with the control condition, along with a significant

decrease in pain perception. There was not a strong correlation between the

strength gains and pain decrease, thus indicating other factors were responsible

for these changes.

Gigante et al [24] examined the medialization effect of taping on the patella

through computed tomography (CT). Sixteen females with patellofemoral pain

related to patellar incongruence were examined by way of CT before and after

patellar taping. The results showed no difference in the lateralization of thepatella and thus does not support that passive medial positioning is accomplished

through taping.

Powers evaluated a series of female patellofemoral patients and controls for

patellar motion through kinematic magnetic resonance imaging (KMRI) and vasti

muscle activity by way of EMG [25]. Medial/lateral displacement and tilt of the

patella were measured during resisted knee extension (by way of KMRI) as vasti

EMG was simultaneously collected. The investigators summary indicated

increased VM activity most likely is in response to abnormal patellar kinematics

rather than the cause. This investigator further proposes the role of the femoralsulcus as being an important determinant of patellar kinematics in the last 30of

extension [26].

Kowall et al performed a prospective study of patellar taping compared with a

control group of patients receiving the same treatment without the addition of

taping [27]. These patients were also assessed through vasti EMG during stair

stepping actions; pain (VAS), and strength by way of concentric isokinetic

contractions. Significant increases in EMG amplitude and strength (concentric

peak torque) and reductions in pain were seen in all subjects. No differences in

outcomes were associated with the addition of taping to the procedures. Althoughthere was no specific benefit to the use of tape, it should be recognized that there

were significant improvements for each group demonstrating a successful

rehabilitation regimen.

Bracing has been espoused as assistive in the management of patellofemoral

pain patients, particularly those with a significantly increased lateralization of the

patella. Palumbo evaluated a dynamic patellar brace (medial force application)



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with 93% of 62 patellar pain patients responding positively to its use [28]. Levine

likewise reported a 77% response rate in similar patients using a patellar strap

[29]. Shellock et al [30] evaluated the ability of a dynamic brace to createrealignment of the patella in a patient known to have significant lateral patellar

subluxation. KMRI was able to demonstrate a reduction of lateralization (thus

realignment) and with the brace being used during the patients rehabilitation

regimen successfully. Worrell et al [31] documented similar results examining

taping and bracing by way of MRI and also significant reductions in pain during

their applications.

Conway et al [21] evaluated the Palumbo brace with use in patellofemoral

pain patients and its effect on force output and perceived pain. Patients

demonstrated an immediate significant increase in eccentric quadriceps outputand decrease in pain perception. There was not a correlation between the increase

in torque and the decrease in pain, thus demonstrating other factors play a role in

this process.

Timm [32,33] has published information related to the use of a dynamic

restraint brace in patellofemoral patients with some positive functional and

financial (cost reduction) outcomes. There have not been peer-reviewed pub-

lications duplicating these data.

Hung and Gross [34] evaluated the impact of a 10 lateral or medial wedge

on VMO and VL EMG activity during a single leg partial squat and maximalisometric quadriceps contraction in extension. The normalized EMG showed

greatest activity during the single leg partial squat but there were no differ-

ences with the use of wedges. The investigators conclude that the alterations

seen with the use of wedges may be the result of mechanical factors other than

EMG changes.

There is evidence that the application of patellar taping or a brace significantly

reduces perceived pain and improves quadriceps output. There is limited support

that taping or bracing influences patellar alignment, and if it does occur at all, it is

likely to be only in a few specific patients.Because a decrease in pain perception occurs, the application of tape or brace

can be an assistive measure enabling the inclusion of pain-free exercises. It is

important to recognize the use of these modalities as a means to an end: pain-free

exercise allowing an increase in quadriceps function.

Does the type of exercise or specific modality significantly alter the demand on

the quadriceps?

A variety of exercises have been recommended for the rehabilitation ofpatellofemoral patients. The literature gives many anecdotal and technique driven

answers rather than a large volume of evidence-based practice data. A recent

review of evidence-based practice outcomes related to rehabilitation of the knee

gives the most common documented outcomes to the use of therapeutic exercise

[35]. Thus the use of active exercise was seen to be effective whereas many other

interventions have limited published support. The questions become: (1) is there



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a specific exercise sequence that will be most effective for patellofemoral pain

patients? and (2) are there modalities that can bias the quadriceps response?

Gryzlo et al [9] found the highest EMG levels in the VMO and VL to occur interminal extension, particularly with load (resistance). They also showed the

quadriceps EMG activity increases during ascent from a squat, emphasizing the

concentric action requiring a higher level of EMG. They also showed no selective

action for the VMO. Laprade [10] found similar values with the highest demand

on the VMO and VL occurring at terminal extension in isometric contractions.

Souza and Gross [12] compared patients with patellofemoral pain with a

group of controls for VMO/VL EMG activity in isometric or stair-climbing

activities. They found no true isolated exercises (VMO selective activities) but

did find that patients ratios of VMO/VL were greater during the isotonic stairclimbing than during isometric exercises. This could relate to the closed-chain

pattern, believed by some investigators to enable enhanced VMO and VL

exercise. Witvrouw et al [36] attempted to compare the efficacy of the open

kinetic chain exercise pattern versus the closed kinetic chain pattern in patello-

femoral pain patients. They randomly assigned 60 patellofemoral pain patients to

either an open chain or closed chain program of exercises. These patients

participated in five weeks of rehabilitation with a variety of objective and

subjective outcome measures. Both groups demonstrated significant improve-

ments but there were no differences in the level of improvement between the twoexercise groups. They found significant improvements for both training groups

in quadriceps strength assessment (open chain) as documented with isokinetic

evaluation. The greatest gains were at higher velocities (180, 300 per second).

These data agree with the results of Kowall, [27] who found better results at 180

per second, rather than at 60 per second. This points toward using higher

Table 1

Patellofemoral classifications and specific protocols

Classification Patellar compression

syndromes

Patellar instability Biomechanical dysfunction

Evaluation

features

Excessive pressure,

typically lateral

patellar facet

Abnormal patellar

ligamentous or bony

structures, active/passive

instability

Significant imbalances:

foot, limb length

discrepancies, and

flexibility deficits

Muscular

concepts

Exercise lower in

ROM, minimize

terminal

extension loads

Avoid terminal extension,

exercise lower in

ROM (4590),

Patella in the groove

Treat specifics: orthotics,

inserts (lifts), stretching

(if orthotics: watch out to

not cause limb lengthdiscrepancy by blocking

pronationmay require lift

to other leg



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velocities during training when possible to better simulate function and to reduce

pain and other inhibitory influences.

Sheehy et al [37] examined the vasti EMG activity in the commonly usedstair-climbing activity in patellofemoral pain patients and control subjects. There

were no differences in the ratio between patients and control subjects in any

assessment. They found the peak VMO/VL ratio occurred during ascent

(concentric) with lower values seen in descent (eccentric).

Attempting to predict the effect of exercise on long-term outcome is

difficult. Natri et al [38] performed a prospective seven-year follow-up study

of chronic patellofemoral patients. Their results support the concept that

restoring the quadriceps functional capacity is important in the long-term

success of these patients.Several clinicians and researchers have used biofeedback and electrical

stimulation in treatment programs and research studies to alter quadriceps demand

or response. Draper demonstrated the positive effect of biofeedback as an adjunct

in facilitating the return of quadriceps function following anterior cruciate

ligament (ACL) reconstruction [39]. Her data support the use of biofeedback to

enhance voluntary recruitment of motor units (often referred to as re-education).

Ingersoll and Knight [40] showed patellar medialization (decreased congruence

angle) through the use of VMO biofeedback during quadriceps strengthening

compared with the exercises used alone. Wise et al [41] developed a three-phasesequential protocol culminating in an attempt to use biofeedback to facilitate

VMO activity during functional movements. LeVeau [42] recommended a two-

phase process of attempting to decrease VL activity during quadriceps setting

followed by attempting to enhance VMO. Electrical stimulation has been shown to

assist in muscle activation and medialization of the patella in vivo. Koh et al [43]

Direct patellar

trauma

Soft tissue

lesions

Overuse syndromes Osteochondritis

diseases

Neural disorders

Direct impact

to patella

dashboard

Palpation or

tension pain

about the knee/

patella (plica,

fat pad, bursa)

Tendon (itis/osis)

palpation

of the apophyses

(patella or tibia)

Deep pain,

dissecans of

patella or femur

Pain out

of proportion

Avoid pain

and crepitation,

exercise in

pain-freeROM, partial

ROM isotonics

and isometrics

(above/below

painful area

of contact)

Avoid pain,

decrease

inflammation,

Avoid exercisethat causes

irritation/pain,

isometrics and

selected/partial

ROM isotonics

Avoid acute

painful actions,

quadriceps

program-eccentricemphasis: 10 12

weeks required,

pain modulation,

protect tibia

insertion from

direct impacts

(donut pad)

Gentle quadriceps

strengthening,

pain-free program

Often medial

saphenous nerve,

do it early, early

pain managementis the best

initial option



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showed that through passive electrical stimulation of the VMO a patellar

medialization occurred whereas lateralization occurred during unstimulated active

knee extension. Bohannon [44] found a similar effect, with VMO electricalstimulation providing maintenance of a medial patellar position in a patient

experiencing lateral patellar dislocation.

Although no quadriceps exercise is able to isolate specific portions of the

mechanism, it seems isolation is not required for long-term success. The appro-

priate selection of exercise should be based on signs and symptoms as discerned

during the evaluation. The integration of open and closed chain exercises may be

required for optimal rehabilitation in many patients. The use of biofeedback and

electrical stimulation may provide adjuncts to overall treatment.

Unfortunately, too many clinicians attempt to treat all patellofemoral patientsby way of a single sequence of exercises. This does not work well as the needs of

the patellar subluxating patient are different from those of the patient with an

articular cartilage defect. Most patellofemoral patients have signs and symptoms

that allow them to be grouped or classified, enabling a specific protocol to match

their needs to be applied. We recommend using a classification scheme to provide

an evaluation-based regimen and also better defining outcomes with these

challenging patients [45]. Our system provides the following eight classes with

recommendations for specific rehabilitation: patellar compression syndromes,

patellar instability, biomechanical dysfunction, direct patellar trauma, soft tissuelesions, overuse syndromes, osteochondritis diseases, and neurologic disorders

[45]. This process of evaluation, classification, and specific protocol and applica-

tion is presented in Table 1. It is important that clinicians recognize their level of

success should be 80%+ overall, but not with each of these classes will this be true.

Summary

Patellofemoral patients are among the most common yet most challengingindividuals presenting for orthopedic care. The key word in the previous sentence

is individual. A single protocol of care is not sufficient for these special

individuals. Many concepts have been evaluated through review of the peer-

reviewed literature with the following highlights: (1) the concept of VMO

isolation through specific exercise should no longer be part of our lexicon; (2)

patellofemoral patients improve when they are able to enhance quadriceps

functional patterns by way of pain-free exercise; (3) patellofemoral patients do

not fit into a single box but rather require an evaluation-based classification

and specific interventional pattern.Many of the special techniques used by clinicians in treating these patients

have not been well defined through research and also are lacking in evidence of

clinical efficacy. We also must recognize, however, that good clinical observa-

tions can be the first step in defining what questions should be asked and how

they can be answered. It is vital that we answer the questions without allowing

bad science through dogma and anecdote to prevail. Likewise, we need to be



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diligent in determining our successes and failures through well designed and

implemented clinical and research studies.

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16 - Control Muscular de La Patela