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Table 1Overview of Diagnosis and Treatment of Anterior Knee Pain Type of Anterior Knee Pain Possible Diagnosis Key Elements of History and Physical Examination Testing Management Constan

Diagnosis and Treatment

Abstract

Anterior knee pain is a frequent clinical problem It provides a common challenge to diagnose and manage Basic science studies have provided insight into the origin of anterior knee pain and refined understanding of the anatomy Clinical evaluation has progressively focused on the contribution of the entire lower extremity to patellofemoral function Nonsurgical management has been refined by the concept of the″envelope of function″and

by increased understanding of the neuromuscular control of the knee Indications for lateral release have been clarified and narrowed Although anteromedial transfer of the tibial tuberosity is helpful in certain circumstances, reports of postoperative fracture have led to less aggressive rehabilitation protocols Chondral resurfacing of the patellofemoral joint and patellofemoral arthroplasty are evolving Emphasis should remain on nonsurgical management, which is sufficient in most patients

The diagnosis and treatment of anterior knee pain is challeng-ing, and the topic has been well reviewed.1-3The term “anterior knee pain” is used to group together a number of different but related pathologic entities The history and physical examination,

complement-ed by imaging studies, are helpful in defining as precisely as possible the origin of the patient’s complaint Pa-tellofemoral symptoms fall into two general categories: instability and pain Overlap of pain and instability does occur, but most often, symp-toms are more directly caused by one or the other

The patient with true patellar in-stability reports that the patella ei-ther dislocated (requiring a reduc-tion) or shifted laterally (partial dislocation with spontaneous reduc-tion) Such injuries are typically as-sociated with weight bearing and torsional trauma It is important not

to confuse patellar instability with reports of the knee “giving way” or buckling Such symptoms typically include the knee collapsing into flexion and are more likely caused

by quadriceps insufficiency second-ary to pain, deconditioning, or sec-ondary joint effusion True patellar instability is a topic separate from the subject of anterior knee pain The origin of anterior knee pain may be patellofemoral when it oc-curs during prolonged knee flexion

or when climbing or descending stairs The pain is often localized in the peripatellar or retropatellar area and may be vague in nature Careful attention to pain diagrams can be helpful in localizing symptoms and

in focusing the physical examina-tion.4Determining whether the pain

is constant, activity related, or sharp and intermittent can help narrow the list of potential diagnoses Table

1 provides an overview of potential

William R Post, MD

Dr Post is in private practice,

Mountaineer Orthopedic Specialists,

LLC, Morgantown, WV.

Neither Dr Post nor the department with

which he is affiliated has received

anything of value from or owns stock in a

commercial company or institution

related directly or indirectly to the

subject of this article.

Reprint requests: Dr Post, Mountaineer

Orthopedic Specialists, LLC, 1197

Pineview Drive, Morgantown, WV

26505.

J Am Acad Orthop Surg

2005;13:534-543

Copyright 2005 by the American

Academy of Orthopaedic Surgeons.

Table 1

Overview of Diagnosis and Treatment of Anterior Knee Pain

Type of Anterior

Knee Pain Possible Diagnosis

Key Elements of History and Physical Examination Testing Management Constant pain,

not

activity-related

Sympathetic mediated pain

Evaluate for signs and symptoms of sympathetic dysfunction

Bone scan Pain management

referral for sympathetic blockade Postoperative

neuroma

Focal tenderness reproducing symptoms, especially over scars

Local anesthetic injection

Neuroma excision

Referred radicular pain

Examine hip, lumbar spine, and saphenous nerve

Radiographs, MRI, bone scan

Determined by primary pathology Symptom

magnification for secondary gain

Careful attention to psychosocial issues

Psychiatric evaluation Psychiatric counseling

Sharp

intermittent

pain

Loose bodies;

unstable chondral pathology

Effusion likely with loose body; differentiate from true patellar instability by history and by examining for patellofemoral ligament laxity

Radiographs, MRI, arthroscopy

Arthroscopy, chondroplasty

Activity-related

pain

Soft-tissue overload without patellar malalignment (eg, patellar tendinitis, quadriceps tendinitis, pathologic plica syndrome, fat pad syndrome, ITB syndrome, early lateral patellar compression syndrome)

Focal tenderness over the involved structure reproducing the symptom;

associated flexibility deficits (eg, prone quadriceps testing, ITB syndrome, lateral retinaculum, hamstring, hip)

MRI (soft-tissue assessment); CT scan when malalignment suspected

Rehabilitation, arthroscopic or open treatment for tendinosis or other specified pathology, lateral release with documented patellar tilt without

instability and minimal chondrosis

Articular tissue overload (eg, posttraumatic chondromalacia

or arthrosis, degenerative arthrosis from chronic malalignment)

Effusion; asymmetric crepitus with passive flexion/extension; pain with direct articular compression in various degrees of flexion

Radiographic assessment: patellar axial; MRI, CT with

or without arthrogram;

injections, bone scan

Rehabilitation, realignment with chondroplasty or resurfacing procedures to unload pathologic lesions, arthroplasty in end-stage conditions

in patients with limited activity level Inflammatory

arthritides, myalgias

Examine other joints and typical systemic symptoms to confirm

Serologic testing Pharmacologic agents

Systemic disease or illness producing weakness and general deconditioning

History of such illness or inactivity, nonspecific examination findings

Rehabilitation and medical treatment for the specific medical condition (eg, thyroid hormone for hypothyroidism)

CT = computed tomography, ITB = iliotibial band, MRI = magnetic resonance imaging

diagnoses that can cause anterior

knee pain as well as suggestions for

physical examination, further

test-ing, and management Accurate

di-agnosis is key to focusing both

surgi-cal and nonsurgisurgi-cal management

Anatomy and

Pathomechanics

Trying to unravel the mysteries of

anterior knee pain begins with

im-proved understanding of the

anato-my Biedert et al5 found that free

nerve endings are concentrated in

the patellar tendon, retinacular

tis-sues, pes anserinus, and, in

particu-lar, the synovial tissues and fat pad

The pain sensitivity of

intra-articular structures was defined by

Dye, who described the sensations

he experienced during arthroscopic

probing of his own knees without

intra-articular anesthesia.6He found

that the fat pad and synovial tissues

were especially sensitive and that

the articular surfaces, menisci, and

ligaments were much less

sensi-tive.6Articular cartilage is aneural,

but subchondral bone has the

poten-tial to generate pain when

overload-ed by serious overlying cartilage

de-ficiency

Other studies have supported a

soft-tissue origin of the pain

Sub-stance P and calcitonin gene–related

peptide, which are

neurotransmit-ters of nociceptive fibers, are

prom-inent in retinacular tissues and in

the fat pad Sanchis-Alfonso et al7

found perivascular proliferation of

nociceptive axons in the retinacular

tissue of patients with anterior knee

pain at the time of realignment

sur-gery Neural growth factor hastens

neural proliferation and can be

in-duced by ischemia.8Higher levels of

neural growth factor also have been

found in the lateral retinaculum of

patients with pain as a primary

com-plaint compared with the levels

found in patients with

patellofemo-ral instability These observations

have led to the hypothesis that

is-chemia of the retinacular tissues

(perhaps caused by tension overload) may induce pathologic neural prolif-eration and pain.9This is one poten-tial mechanism for the occurrence of anterior knee pain provoked by pa-tellar knee flexion

Witonski and Wagrowska-Danielewicz10 reported that sub-stance P–immunoreactive nerve fi-bers are widespread within the soft tissues around the knee These tis-sues include the retinaculum, syn-ovium, fat pad, and, in some circum-stances, bone In patients with anterior knee pain, more nociceptors were found in the fat pad and

medi-al retinaculum than in patients with osteoarthritis or anterior cruciate ligament injury In addition to veri-fying the presence of a rich nerve supply to these soft tissues, these studies support the concept of chronic nerve injury in the soft tis-sues as a source of anterior knee pain

Subchondral bone is also richly innervated Several studies have shown elevated intra-articular pres-sure in the patella to be associated with anterior knee pain Decompres-sion has been tried when pain was provoked by a pain provocation test, which was believed to increase intraosseous pressure Preliminary success has been reported, even though the provocation test did not produce pain in all patients with an-terior knee pain.11,12

Understanding and analysis of pa-tellar tracking has progressed mark-edly, as demonstrated by

Katchburi-an et al.13 Consistent terminology for patella position and patellar tracking are both improving; appre-ciation of the complexity of the mo-tion involved is a necessity (Figure 1) Motions that can be measured in-clude medial and lateral translation

of the patella, axial plane rotation of the patella (ie, tilt), coronal plane ro-tation (ie, patellar spin), and sagittal plane flexion.3In vivo and in vitro studies show that in early flexion, the patella shifts medially 4 to 9 mm

as it is drawn into the trochlea The

patellae generally tilt medially in vitro during early flexion by <4° be-fore beginning to tilt laterally up to

<4° as flexion progresses to 90° In vivo studies of patellar tilt have been less consistent Studies of coronal plane patellar rotation also are not very consistent, but they generally demonstrate that the inferior pole of the patella rotates laterally as knee flexion progresses There is much room for improvement in the clini-cal evaluation of patellar motion As yet, in vivo understanding of patellar tracking is incomplete

Dye et al14 investigated the soft tissues anterior to the patella and found differences compared with tra-ditional anatomic texts Apparently,

a superficial transverse fascial layer exists, with a deeper intermediate oblique aponeurotic layer, both of which are superficial to the deep rec-tus femoris fibers, which are directly applied to the bone of the patella Eckhoff et al15reported that the sul-cus of the trochlea in both normal and osteoarthritic knees is actually slightly lateral to the midplane be-tween the medial and lateral femoral condyles Their finding is contrary to the traditional assumption that the sulcus is in the midline Radio-graphic imaging of the patella dem-onstrated that the geometric center

of the patella was slightly lateral (2.2

± 0.9 mm) to the patellar ridge.16Yet when interpreting imaging studies of the patellofemoral joint, bony con-gruence often may not reflect the real articular congruence Stäubli and colleagues17,18used magnetic res-onance arthrograms to demonstrate that, because of variable thickness of the articular cartilage on the patella, images of bone that appear incongru-ent may actually have excellincongru-ent car-tilage congruity

Clinical Evaluation

It is important to remember that not all anterior knee pain is associated with measurable abnormalities of patellar alignment or individual

an-atomic variations Patellofemoral

malalignment must not be

consid-ered a synonym for anterior knee

pain Measurable malalignment of

the patellofemoral joint may or may

not be a key factor in any specific

patient with anterior knee pain

Studies have failed to be sensitive in

consistently finding radiographic

malalignment in patients with

patel-lofemoral pain.19 Are radiographic

findings (eg, shallow sulcus, patella

alta, lateral tilt angle) pathologic if

the patient is asymptomatic? Or is

the effect of the preexisting

differ-ence in morphology critical only in

the presence of injury, repetitive

overload, or neuromuscular

decom-pensation? There are no definite

an-swers to these questions

Misunderstanding of the

patho-genesis and inappropriate treatment

can occur when all pain is assumed

to be associated with some degree of

patellar malalignment This

as-sumption may result in surgical

re-alignment in patients in whom

alignment may not be the primary problem A well-intentioned opera-tion to realign a normally aligned pa-tellofemoral joint can lead to a poor outcome Imbalances in the extensor mechanism include dynamic and static neuromuscular factors The patellar position on static imaging is only part of the pathophysiology Re-cent literature has pointed out the value of recognizing other causes of patellofemoral pain in patients with normal anatomic alignment, such as patellar or quadriceps tendinitis,20

postoperative neuromas,21 and sa-phenous neuritis.22

The role of the entire leg in the pathogenesis of anterior knee pain has come under increased scrutiny

Witvrouw et al23evaluated 282 ado-lescents (average age, 18.6 years) and noted that 7% to 10% developed pa-tellofemoral pain within 2 years An-thropometric, physical examination, psychological, and

electromyograph-ic data were collected prospectively

to discern which factors would

pre-dict the onset of pain Notable find-ings were decreased quadriceps and gastrocnemius flexibility, increased vastus medialis obliquus (VMO) re-flex response time and delayed VMO firing versus the vastus lateralis, de-creased explosive strength, and in-creased thumb to forearm mobility Factors that did not correlate with the onset of knee pain included alignment (ie, Q angle), psychologi-cal testing, isokinetic strength, and any of the anthropometric data (eg, height, weight) Two important studies found electromyographic dif-ferences, proving that contraction of the vastus lateralis came before the VMO in symptomatic patients com-pared with control subjects.24,25

The hip extensor muscles play a critical role in lower extremity func-tion Zhang et al26found that the hip extensors contribute 25% of the energy absorption during landing When the hip musculature does not absorb its share of the load, other parts of the extremity must

compen-Figure 1

Clinically relevant patellar position relative to the trochlea A, Axial view demonstrating medial and lateral translation and patellar rotation (commonly called tilt) B, Coronal view demonstrating internal and external rotation (commonly called spin) C, Sagittal

view demonstrating flexion (Adapted with permission from Post WR, Teitge R, Amis A: Patellofemoral malalignment: Looking

beyond the viewbox Clin Sports Med 2002;21:521-546.)

sate Deficits in hip strength add to

load on the knee, even independent

of the rotational changes that may

occur in the presence of hip

weak-ness Providing further evidence of

entire extremity involvement, Baker

et al27tested 20 patients with

anteri-or knee pain and found that knee

joint proprioception was abnormal

in both weight-bearing and non–

weight-bearing tests compared with

a control population

Understanding patellofemoral

disorders does require more than a

thorough understanding of anatomy

Dye28defines the envelope of

func-tion as the “range of load that can be

applied across an individual joint in

a given period without

supraphysio-logic overload or structural failure.”

Essentially, an asymptomatic joint

has adequate tissue homeostasis, so

the amount of load applied to the

in-volved joint is successfully handled

When the joint is out of

homeosta-sis, pain results The ability of a joint

to tolerate loading depends on

mul-tiple factors, not just the

radiograph-ic alignment of the joint The

abso-lute amount of loading over time is

an important factor in overuse

inju-ries For example, patients suffering

from anterior knee pain caused by

blunt trauma may have a positive

bone scan (a measure of physiology,

not structure) that resolves over

time as their pain does.29The knee is

out of homeostasis on the bone scan

while it is abnormal, but

homeosta-sis is restored over time Keeping

pa-tients within their pain-free

enve-lope of function, however narrow

that may be, is a key to successful

treatment

For example, a previously

asymp-tomatic middle-aged,

decondition-ed, sedentary, slightly overweight

woman who rapidly increases her

activity by taking a five-mile hike

up a mountain trail may present 10

days later with anterior knee pain, a

small effusion, peripatellar

tender-ness, and a patellar axial radiograph

suggesting mild patellofemoral

ar-throsis with lateral patellar tilt, and

lateral subluxation Her increased activity resulted in loss of joint tis-sue homeostasis Relative rest, pain control, and anti-inflammatory mo-dalities likely would restore her daily function, even in the presence

of her preexisting radiographic

“malalignment.” Acute treatment consists of keeping her within her new envelope of function (ie, activi-ties with low enough load that she

is minimally symptomatic), while working gradually to increase her envelope of function by weight loss, strengthening, and flexibility exer-cises If such a patient does not seek care but rather waits out the pain, she would likely become weaker from the decreased activity level and less flexible from the decrease in activity; also, she might gain weight because of the inactivity

Similarly, patients with systemic illnesses, such as thyroid disorders or cancer, can develop knee pain as their muscle weakness decreases their envelope of function The next time such a patient tries to increase her or his activity level, the envelope

of function is even smaller The pa-tient becomes caught in this cycle and presents much later with a his-tory of chronic knee pain and radio-graphic evidence of malalignment

Rescue from the deconditioned state

is not possible in some patients, and surgery may be necessary Theoreti-cally, a patient who does not respond

to a rehabilitation program has in-curred such a degree of macrostruc-tural damage that the joint cannot return to a homeostatic state Thus, surgical intervention to remove the ongoing focus of inflammation or to realign the patellofemoral joint to decrease pathologic loading would be rational It is important to remember that there are no absolute radio-graphic indications for surgery

Malalignment can be understood

as a situation “where bony align-ment, joint geometry, soft tissue re-straints, neuromuscular control and functional demands combine to pro-duce symptoms as a result of

abnor-mally directed loads which exceed the physiological threshold of the tissues.”3With regard to surgery for realignment, current clinical stan-dards for assessing patellofemoral alignment lack complete informa-tion, such as patellar spin and sagit-tal plane flexion Understanding of the effect of standard realignment procedures on all components of alignment and tracking is currently limited.30 Unfortunately, in vivo understanding of the effect of re-alignment procedures on three-dimensional tracking is even more lacking With increased appreciation

of the pathophysiology of soft-tissue pain comes the consideration that symptomatic relief may occur as a result of cutting certain soft-tissue structures, in addition to (or possibly independent of) any effect that sur-gery may have on macrostructural alignment Even the postoperative period of relative rest and structured rehabilitation may contribute to res-toration of joint homeostasis

Nonsurgical Management

Although controversy exists over the best methods to improve leg strength

in patients with anterior knee pain, the traditional concept of trying to achieve isolated VMO exercise is not supported by extensive and persua-sive recent literature.31One random-ized study evaluated the effects of open kinetic chain exercise (non– weight-bearing) versus closed chain exercise (weight-bearing) in a group

of patients with anterior knee pain.32

Although both types of exercise pro-duced improvements in strength, pain relief, and return to function, the closed chain exercises produced less pain, better triple jump (func-tional improvement), and less sub-jective “clicking.” It would be short-sighted to discard either open or closed chain exercises entirely Several thorough reviews of non-surgical treatment have been pub-lished recently;33,34many are

partic-ularly notable Doucette and

Goble35 reported that 84% of

pa-tients improved after 8 weeks of

quadriceps rehabilitation and

stretching Patellar axial radiographs

demonstrated some improvement

after treatment, although the values

were within previously published

normal limits at both times, and

val-ues were equivalent between the

symptomatic and asymptomatic

knees Long-term (7-year) follow-up

of 49 patients treated with

quadri-ceps exercises, rest, and nonsteroidal

anti-inflammatory drugs showed

that nearly 75% of patients

main-tained improvement from 6 months

to 7 years.36Many factors were

stud-ied, including radiographs, magnetic

resonance imaging, and other

base-line clinical findings, but none

corre-lated with the treatment result.37

Unfortunately, no criteria,

examina-tion, or treatment predicted which

patients would respond well In

par-ticular, patellar taping has generated

much interest, with studies showing

pain relief, alterations in the timing

of VMO contraction, and increased

exercise tolerance.38,39

Although all of these studies

con-firmed that nonsurgical

manage-ment can be successful and shed

light on the nature of the problem,

only very recently has a double-blind

multicenter placebo-controlled trial

of nonsurgical treatment been

re-ported Seventy-one subjects aged

<40 years were randomly assigned to

either a placebo or a treatment

group.40 Subjects were included if

they reported anterior or

retropatel-lar knee pain on at least two of the

following activities: prolonged

sit-ting, stairs, squatsit-ting, running,

kneeling, and hopping/jumping

Pa-tients had symptoms for at least 1

month, an average pain level of 3 on

a 0 to 10 visual analog pain scale,

and insidious onset of symptoms

The treatment group had six weekly

visits involving patellar taping,

quadriceps training with

biofeed-back, gluteal strengthening, and

an-terior hip and hamstring stretching

The placebo group had placebo tap-ing, turned-off ultrasound, and a pla-cebo “medicated gel.” Thirty-five percent of patients in the placebo group believed they were in the ac-tive treatment group When mea-sured by improvement in pain or function, the treatment group

showed statistically (P≤0.04) better improvements compared with the placebo group (which also showed some improvement)

Therefore, a nonsurgical program must include activity modification based on patient history Athletes must modify their training, and ad-justments should be made in work and daily activities for nonathletes

Such modifications are important to get the patient back within his or her envelope of function Particular at-tention also should be paid to flexi-bility, especially of the quadriceps, a common deficit in patients with an-terior knee pain Strengthening must

be done without causing severe pain

Strengthening may often be

facilitat-ed by patellar taping Open or closfacilitat-ed chain exercise programs are individ-ualized to limit pain, which will fa-cilitate regular exercise and effective strengthening Emphasis on hip strengthening has also been very helpful Nonsurgical management should be pursued until both the cli-nician and patient are certain that a plateau has been reached in the

lev-el of pain and function This usually requires at least 3 months of careful and compliant rehabilitation Be-cause very few patients with

anteri-or knee pain do not respond to reha-bilitation, providers would be well advised to carefully reconsider the differential diagnosis when faced with a patient who has not

respond-ed as expectrespond-ed

Surgical Management

Because of the success of nonsurgi-cal management, surgery for

anteri-or knee pain is not necessary in most patients Successful surgical treat-ment requires an accurate diagnosis,

taking particular care to ascertain whether there are symptoms of pa-tellar instability or signs of patel-lofemoral malalignment on physical examination and imaging studies Patients with normal alignment and

no instability may be symptomatic from tendinosis in the quadriceps or patellar tendons, pathologic hyper-trophy and inflammation in the me-dial plica, or less common causes (eg, neuromas) Severe damage to the articular surface of the patella or the trochlea can at times be the isolated cause of symptoms

However, before concluding that the anterior knee pain is caused by chondromalacia of the patella, other causes must be ruled out Isolated le-sions of the articular cartilage of the patellofemoral joint are one of the less common causes of anterior knee pain In such patients, arthroscopic débridement of Outerbridge grade 2 and 3 chondral lesions can be useful

In their review of 36 patients with chondromalacia patellae, Federico and Reider41reported 57.9% good or excellent results in patients with traumatic onset; patients with atrau-matic onset had 41.1% good or ex-cellent results All but four patients thought the surgery was beneficial

In one recent randomized, non-blinded study of a similar group of patients with Outerbridge grade 2 and 3 chondromalacia, bipolar radio-frequency débridement was com-pared with mechanical débridement alone.42Both groups improved at fi-nal 2-year evaluation, but the radio-frequency group scored significantly

better (P = 0.0006) However,

con-cerns remain about the potentially damaging long-term effects of radio-frequency energy on bone and carti-lage.43Although confirmation of the role of radiofrequency chondroplasty will depend on future randomized, blinded studies, these studies41,42 to-gether show the positive value of chondroplasty in carefully selected patients with grade 2 and 3 lesions Lateral release can be effective in treating a well-defined subset of

pa-tients with anterior knee pain, but it

is seldom needed Most patients

with pain and a tight lateral

retinac-ulum can be effectively treated

non-surgically Lateral release may help

by relieving pressure in the lateral

retinaculum, dividing neuromatous

nerves in the lateral retinaculum, or

relieving pressure on the lateral

fac-et of the patella; at present, the exact

mechanism cannot be stated with

certainty The role of lateral release

in managing anterior knee pain has

been clarified in the past 10 years

Several studies have shown that the

ideal candidate is a patient with no

history of patellar instability.44,45

The degree of chondral damage also

seems to be important Aderinto and

Cobb46reported satisfactory results

in only 59% of patients with

ad-vanced patellar arthrosis treated

with lateral release Conversely,

Shea and Fulkerson47reported 92%

good and excellent results after

later-al release when there were no

chon-dral lesions greater than grade 1 and

2 and there was evidence of lateral

tilt on computed tomography

O’Neill48compared the results of

arthroscopic lateral release with

those of open lateral retinacular

lengthening and found slightly

bet-ter results afbet-ter the lengthening

pro-cedure, although chondral damage

was less severe in this group This

study raises the question whether a

lengthening procedure is a good

al-ternative to release The

biomechan-ical effects of lateral release have

been shown to be related to the

length of the release, especially in

the distal direction Although it is

not known with certainty the

clini-cally necessary amount of release,

extending the release distally to the

level of the tibiofemoral joint line

does result in a measurable increase

in patellar mobility.49In a recent

sur-vey of the International

Patellofem-oral Study Group (a group of

clini-cians with special interest and

expertise in patellofemoral

disor-ders), lateral release was an

infre-quently done procedure Indications

for the procedure were anterior knee pain with evidence of a tight lateral retinaculum on physical examina-tion.50

Complications of lateral release can include persistent or worsening pain or instability When present, these complications can make the preoperative symptoms seem minor

Particularly in the setting of a nor-mally aligned patella that has been treated with lateral release, medial subluxation can occur In this situa-tion, an excessive lateral release that included division of the vastus later-alis tendon also should be

suspect-ed Medial subluxation must be suspected clinically in any patient reporting persistent pain after

later-al release.51Symptoms often include

a sense of the patella moving

lateral-ly, a complaint that can mislead cli-nicians The cause of this sensation

is the patella’s momentarily sublux-ating medially out of the trochlea in early flexion, then snapping back lat-erally into the trochlea with further flexion When the clinician fails to recognize this diagnosis and instead interprets the symptoms to be recur-rent lateral subluxation, further pro-cedures, such as tibial tuberosity medial transfer or medial reefing, may be recommended However, such procedures would only worsen the symptoms

Medial patellar subluxation must

be confirmed by clinical examina-tion Two maneuvers have been de-scribed Fulkerson52 recommended pushing the patella medially with the knee in extension, then suddenly flexing the knee When this repro-duces the complaint, medial sublux-ation is likely Nonweiler and DeLee53suggested examining the in-volved knee in a lateral position The involved knee is placed with the lat-eral side up, allowing the involved patella to sag via gravity medially out of the trochlea The patient with medial patellar subluxation will be unable to flex the knee Nonsurgical management can help to confirm this diagnosis if taping or bracing the

patella into a more lateral position decreases symptoms Hughston et

al54 found that 68% of patients re-ported improvement in their func-tional levels and 75% reported sub-jective improvement by attempts at repair or reconstruction of the lateral retinaculum Surgical management

of this condition involves repair or reconstruction of the lateral release defect; although helpful, this is best considered as a salvage procedure Patients with radiographic or ar-throscopic evidence of lateral patel-lar tilt and subluxation who have failed persistent and patient nonsur-gical management can improve sig-nificantly after lateral release and anteromedial tibial tuberosity trans-fer Pidoriano et al55correlated the results of anteromedial tibial tuber-cle transfer with the location of car-tilage lesions on the patella; they found that proximal and global pa-tellar lesions did less well Their findings correlate with laboratory studies showing that anterior tuber-osity transfer, while decreasing over-all load, shifts load

disproportionate-ly to the proximal patella Careful consideration of the location of car-tilage lesions is recommended when contemplating tuberosity transfer, just as one would do with any other osteotomy to avoid transferring load onto articular lesions

Early weight bearing after antero-medial tubercle transfer should be avoided; two series have demon-strated the potential for fracture dur-ing full weight-beardur-ing activities be-tween 4 and 7 weeks.56,57 Based on this information, rehabilitation should include only partial weight bearing until osteotomy healing is complete, both radiographically and clinically One report indicated that two athletes sustained tibial frac-tures while jogging 6 months postop-eratively; this finding is extremely uncommon, however.58

Procedures to restore cartilage in-tegrity to the patellofemoral joint have not met with widespread suc-cess Efforts are ongoing to evaluate

the usefulness of autologous

chon-drocyte implantation and

osteo-chondral transfers Only relatively

small numbers of cartilage-restoring

procedures in the patellofemoral

joint have been reported, and overall

results are mixed Experience has

shown that careful evaluation and

correction of patellofemoral

align-ment must be included.59-62Less

ag-gressive procedures, such as

chon-droplasty, microfracture, or abrasion,

may be equally advantageous and

should be considered first-line

treat-ments.63

Patellofemoral arthroplasty can

be considered in the presence of true

end-stage arthrosis.64-66Resurfacing

of the patellofemoral joint should be

done only in low-demand patients

after very careful clinical evaluation

clearly shows that this articulation

is the sole cause of symptoms A

bone scan may be a helpful

adjunc-tive test in this setting; significant

uptake in the tibiofemoral joint

indi-cates that isolated patellofemoral

ar-throplasty is not appropriate Mont

et al67 suggested total knee

arthro-plasty for patients aged >55 years

with primarily patellofemoral

arthri-tis Special care is needed at the time

of surgery to ensure that the

exten-sor mechanism is well aligned

Sur-geons undertaking patellofemoral

replacement should be very

experi-enced in patellofemoral realignment

procedures and should be prepared to

combine them with arthroplasty as

needed

Summary

Despite the prevalence of anterior

knee pain, much is unknown

regard-ing the etiology, pathomechanics,

and management of the many

caus-es of this symptom To label this set

of disorders as “patellofemoral

syn-drome” is worrisome because it may

deter some clinicians from trying to

reach a more precise diagnosis

Cli-nicians should strive for the greatest

possible degree of diagnostic

accura-cy and specificity to maximize out-comes

A greater understanding of the natural history of different causes of anterior knee pain also would be of great value; learning to predict which lesions progress over time would allow the clinician to treat those lesions more aggressively

Hypotheses regarding potentially is-chemic neurologic changes that may result from excessive soft-tissue ten-sion may produce insight into new treatments Although significant in-sights have been made in the past 10 years regarding the understanding of the pathophysiology, diagnosis, and treatment of anterior knee pain, there is room for improvement in all areas Particularly promising devel-opments include dynamic magnetic resonance imaging and advances in nonsurgical management in treating the entire extremity, with particular emphasis on the key role of the hip muscles in controlling femoral posi-tion Improvements in imaging ar-ticular cartilage may make possible more precise diagnosis of the loca-tion and severity of cartilage lesions;

however, clinicians need to be cau-tious in concluding that the articular cartilage lesion is the cause of symp-toms Clinicians still need to im-prove their understanding of the role and boundaries of surgery in

anteri-or knee pain Currently, nonsurgical management remains the most pre-dictable method of treatment

References

Evidence-based Medicine:

Referenc-es 23, 32, 36, 37, 40, 48, and 63 are level I or II evidence-based studies

1 Fulkerson JP: Patellofemoral pain dis-orders: Evaluation and management.

J Am Acad Orthop Surg 1994;2:124-132.

2 Post WR: Clinical evaluation of pa-tients with patellofemoral disorders.

Arthroscopy1999;15:841-851.

3 Post WR, Teitge R, Amis A:

Patel-lofemoral malalignment: Looking

be-yond the viewbox Clin Sports Med

2002;21:521-546.

4 Post WR, Fulkerson J: Knee pain dia-grams: Correlation with physical ex-amination findings in patients with anterior knee pain. Arthroscopy

1994;10:618-623.

5 Biedert RM, Stauffer E, Friederich NF: Occurrence of free nerve endings in the soft tissue of the knee joint: A

his-tologic investigation Am J Sports

Med1992;20:430-433.

6 Dye SF, Vaupel GL, Dye CC: Con-scious neurosensory mapping of the internal structures of the human knee without intraarticular anesthesia.

Am J Sports Med1998;26:773-777.

7 Sanchis-Alfonso V, Rosello-Sastre E, Monteagudo-Castro C, Esquerdo J: Quantitative analysis of nerve

chang-es in the lateral retinaculum in pa-tients with isolated symptomatic patellofemoral malalignment: A

pre-liminary study Am J Sports Med

1998;26:703-709.

8 Biedert RM, Sanchis-Alfonso V:

Sources of anterior knee pain Clin

Sports Med2002;21:335-347.

9 Sanchis-Alfonso V, Rosello-Sastre E,

Revert F: Neural growth factor expres-sion in the lateral retinaculum in painful patellofemoral malalignment.

Acta Orthop Scand2001;72:146-149.

10 Witonski D, Wagrowska-Danielewicz M: Distribution of substance-P nerve fibers in the knee joint in patients with anterior knee pain syndrome: A

preliminary report Knee Surg Sports

Traumatol Arthrosc1999;7:177-183.

11 Miltner O, Siebert CH, Schneider U,

Niethard FU, Graf J: Patellar hyper-tension syndrome in adolescence: A

three-year follow up Arch Orthop

Trauma Surg2003;123:455-459.

12 Schneider U, Breusch SJ, Thomsen M,

Wenz W, Graf J, Niethard FU: A new concept in the treatment of anterior knee pain: Patellar hypertension syn-drome. Orthopedics 2000;23:581-586.

13 Katchburian MV, Bull AM, Shih YF,

Heatley FW, Amis AA: Measurement

of patellar tracking: Assessment and analysis of the literature. Clin Orthop2003;412:241-259.

14 Dye SF, Campagna-Pinto D, Dye CC,

Shifflett S, Eiman T: Soft-tissue anat-omy anterior to the human patella.

J Bone Joint Surg Am 2003;85:1012-1017.

15 Eckhoff DG, Montgomery WK, Stamm ER, Kilcoyne RF: Location of the femoral sulcus in the

osteoarthrit-ic knee J Arthroplasty

1996;11:163-165.

16 Asano T, Akagi M, Koike K,

Nakamu-ra T: In vivo three-dimensional

patel-lar tracking on the femur Clin

Orthop2003;413:222-232.

17 Staeubli HU, Bosshard C, Porcellini P,

Rauschning W: Magnetic resonance

imaging for articular cartilage:

Cartilage-bone mismatch. Clin

Sports Med2002;21:417-433.

18 Stäubli HU, Dürrenmatt U, Porcellini

B, Rauschning W: Anatomy and

sur-face geometry of the patellofemoral

joint in the axial plane J Bone Joint

Surg Br1999;81:452-458.

19 Laprade J, Culham E: Radiographic

measures in subjects who are

asymp-tomatic and subjects with

patellofem-oral pain syndrome Clin Orthop

2003;414:172-182.

20 Popp JE, Yu JS, Kaeding CC:

Recalci-trant patellar tendinitis: Magnetic

resonance imaging, histologic

evalua-tion, and surgical treatment Am J

Sports Med1997;25:218-222.

21 Kasim N, Fulkerson JP: Resection of

clinically localized segments of

pain-ful retinaculum in the treatment of

selected patients with anterior knee

pain Am J Sports Med

2000;28:811-814.

22 Morganti CM, McFarland EG,

Cosgar-ea AJ: Saphenous neuritis: A poorly

understood cause of medial knee pain.

J Am Acad Orthop Surg

2002;10:130-137.

23 Witvrouw E, Lysens R, Bellemans J,

Cambier D, Vanderstraeten G:

Intrin-sic risk factors for the development of

anterior knee pain in an athletic

pop-ulation: A two-year prospective study.

Am J Sports Med2000;28:480-489.

24 Cowan SM, Bennell KL, Hodges PW,

Crossley KM, McConnell J: Delayed

onset of electromyographic activity of

vastus medialis obliquus relative to

vastus lateralis in subjects with

patel-lofemoral pain syndrome Arch Phys

Med Rehabil2001;82:183-189.

25 Owings TM, Grabiner MD: Motor

control of the vastus medialis oblique

and vastus lateralis muscles is

dis-rupted during eccentric contractions

in subjects with patellofemoral pain.

Am J Sports Med2002;30:483-487.

26 Zhang SN, Bates BT, Dufek JS:

Contri-butions of lower extremity joints to

energy dissipation during landings.

Med Sci Sports Exerc

2000;32:812-819.

27 Baker V, Bennell K, Stillman B,

Cow-an S, Crossley K: Abnormal knee joint

position sense in individuals with

pa-tellofemoral pain syndrome.

J Orthop Res2002;20:208-214.

28 Dye SF: The knee as a biologic

trans-mission with an envelope of function:

A theory Clin Orthop

1996;325:10-18.

29 Dye SF, Boll DA: Radionuclide imag-ing of the patellofemoral joint in young adults with anterior knee pain.

Orthop Clin North Am 1986;17:249-262.

30 Mizuno Y, Kumagai M, Mattessich

SM, et al: Q-angle influences tib-iofemoral and patellofemoral

kine-matics J Orthop Res

2001;19:834-840.

31 Malone T, Davies G, Walsh WM:

Muscular control of the patella Clin

Sports Med2002;21:349-362.

32 Witvrouw E, Lysens R, Bellemans J,

Peers K, Vanderstraeten G: Open ver-sus closed kinetic chain exercises for patellofemoral pain: A prospective,

randomized study Am J Sports Med

2000;28:687-694.

33 Powers CM: Rehabilitation of patel-lofemoral joint disorders: A critical

re-view J Orthop Sports Phys Ther

1998;28:345-354.

34 Crossley K, Bennell K, Green S,

Mc-Connell J: A systematic review of physical interventions for

patellofem-oral pain syndrome Clin J Sport Med

2001;11:103-110.

35 Doucette SA, Goble EM: The effect of exercise on patellar tracking in lateral

patellar compression syndrome Am

J Sports Med1992;20:434-440.

36 Kannus P, Natri A, Paakkala T,

Jarvin-en M: An outcome study of chronic patellofemoral pain syndrome: Seven-year follow-up of patients in a

ran-domized, controlled trial J Bone

Joint Surg Am1999;81:355-363.

37 Natri A, Kannus P, Jarvinen M: Which factors predict the long-term outcome

in chronic patellofemoral pain syn-drome? A 7-yr prospective follow-up

study Med Sci Sports Exerc 1998;30:

1572-1577.

38 Powers CM, Landel R, Sosnick T, et al: The effects of patellar taping on stride characteristics and joint mo-tion in subjects with patellofemoral

pain J Orthop Sports Phys Ther

1997;26:286-291.

39 Cowan SM, Bennell KL, Hodges PW:

Therapeutic patellar taping changes the timing of vasti muscle activation

in people with patellofemoral pain

syndrome Clin J Sport Med 2002;12:

339-347.

40 Crossley K, Bennell K, Green S,

Cowan S, McConnell J: Physical ther-apy for patellofemoral pain: A ran-domized, double-blinded,

placebo-controlled trial Am J Sports Med

2002;30:857-865.

41 Federico DJ, Reider B: Results of

iso-lated patellar debridement for patel-lofemoral pain in patients with

nor-mal patellar alignment Am J Sports

Med1997;25:663-669.

42 Owens BD, Stickles BJ, Balikian P,

Busconi BD: Prospective analysis of radiofrequency versus mechanical de-bridement of isolated patellar

chon-dral lesions Arthroscopy 2002;18:

151-155.

43 Ryan A, Bertone AL, Kaeding CC,

Backstrom KC, Weisbrode SE: The ef-fects of radiofrequency energy treat-ment on chondrocytes and matrix of

fibrillated articular cartilage Am J

Sports Med2003;31:386-391.

44 Betz RR, Magill JT III, Lonergan RP: The percutaneous lateral retinacular

release Am J Sports Med 1987;15:

477-482.

45 Christensen F, Soballe K, Snerum L: Treatment of chondromalacia patel-lae by lateral retinacular release of the

patella Clin Orthop

1988;234:145-147.

46 Aderinto J, Cobb AG: Lateral release

for patellofemoral arthritis

Arthros-copy2002;18:399-403.

47 Shea KP, Fulkerson JP: Preoperative computed tomography scanning and arthroscopy in predicting outcome af-ter lateral retinacular release.

Arthroscopy1992;8:327-334.

48 O’Neill DB: Open lateral retinacular lengthening compared with arthro-scopic release: A prospective,

ran-domized outcome study J Bone Joint

Surg Am1997;79:1759-1769.

49 Marumoto JM, Jordan C, Akins R: A biomechanical comparison of lateral

retinacular releases Am J Sports

Med1995;23:151-155.

50 Fithian DC, Paxton E, Post W, Panni

AS: Lateral retinacular release: A sur-vey of the International

Patellofemo-ral Study Group Arthroscopy 2004;

20:463-468.

51 Fulkerson JP: Diagnosis and

treat-ment of patients with patellofemoral

pain Am J Sports Med

2002;30:447-456.

52 Fulkerson JP: A clinical test for

medi-al patella tracking (medimedi-al

sublux-ation) Tech Orthop 1997;12:144.

53 Nonweiler DE, DeLee JC: The diagno-sis and treatment of medial sublux-ation of the patella after lateral

reti-nacular release Am J Sports Med

1994;22:680-686.

54 Hughston JC, Flandry F, Brinker MR, Terry GC, Mills JC III: Surgical correc-tion of medial subluxacorrec-tion of the

pa-tella Am J Sports Med

1996;24:486-491.

55 Pidoriano AJ, Weinstein RN, Buuck

DA, Fulkerson JP: Correlation of

pa-tellar articular lesions with results

from anteromedial tibial tubercle

transfer Am J Sports Med 1997;25:

533-537.

56 Stetson WB, Friedman MJ, Fulkerson

JP, Cheng M, Buuck D: Fracture of the

proximal tibia with immediate

weightbearing after a Fulkerson

os-teotomy Am J Sports Med 1997;25:

570-574.

57 Bellemans J, Cauwenberghs F, Brys P,

Victor J, Fabry G: Fracture of the

prox-imal tibia after Fulkerson

anterome-dial tibial tubercle transfer: A report

of four cases Am J Sports Med 1998;

26:300-302.

58 Godde S, Rupp S, Dienst M, Seil R,

Kohn D: Fracture of the proximal tibia

six months after Fulkerson

osteoto-my: A report of two cases J Bone

Joint Surg Br2001;83:832-833.

59 Brittberg M, Lindahl A, Nilsson A,

Ohlsson C, Isaksson O, Peterson L:

Treatment of deep cartilage defects in the knee with autologous

chondro-cyte transplantation N Engl J Med

1994;331:889-895.

60 Peterson L, Minas T, Brittberg M,

Nilsson A, Sjogren-Jansson E, Lindahl A: Two- to 9-year outcome after autol-ogous chondrocyte transplantation of

the knee Clin Orthop

2000;374:212-234.

61 Minas T: Autologous chondrocyte

implantation for focal chondral

de-fects of the knee Clin Orthop 2001;

391:S349-S361.

62 Peterson L, Brittberg M, Kiviranta I,

Akerlund EL, Lindahl A: Autologous chondrocyte transplantation: Biome-chanics and long-term durability.

Am J Sports Med2002;30:2-12.

63 Knutsen G, Engebretsen L, Ludvigsen

TC, et al: Autologous chondrocyte

implantation compared with micro-fracture in the knee: A randomized

trial J Bone Joint Surg Am 2004;86:

455-464.

64 Argenson JN, Guillaume JM,

Aubani-ac JM: Is there a plAubani-ace for

patellofem-oral arthroplasty? Clin Orthop 1995;

321:162-167.

65 Kooijman HJ, Driessen AP, van Horn

JR: Long-term results of patellofem-oral arthroplasty: A report of 56 ar-throplasties with 17 years of

follow-up J Bone Joint Surg Br

2003;85:836-840.

66 Krajca-Radcliffe JB, Coker TP: Patel-lofemoral arthroplasty: A 2- to 18-year

followup study Clin Orthop 1996;

330:143-151.

67 Mont MA, Haas S, Mullick T,

Hun-gerford DS: Total knee arthroplasty

for patellofemoral arthritis J Bone

Joint Surg Am2002;84:1977-1981.